Thermal laser-assisted balloon angioplasty of the superficial femoral artery: A multicenter review of 602 cases David Rosenthal, M D , Felix A. Pesa, M D , W a r r e n L. Gottsegen, MD, John R. Crew, M D , Charles A. Moss, M D , Robert Walsky, M D , and L. Laszlo Pallos, PhD, Atlanta, Ga., Youngstown, Ohio, Metairie, La., Daly
City, Calif.,
and Emerson, N.J. A multicenter review of 602 procedures was performed to evaluate the effects of thermal laser-assisted balloon angioplasty on the superficial femoral artery. Four hundred thirty-nine (73%) patients underwent laser-assisted balloon angioplasty for claudication, and 163 (27%) underwent the procedure for limb salvage. Two hundred ninety-two laser-assisted balloon angioplasty procedures were performed for multifocal stenotic disease (> 80%) diameter reduction), 258 for total occlusion, and 52 procedures for both superficial femoral artery stenosis and occlusion. The initial recanalization rate was 89% (538/602) depending on the length of the lesion. Success of laser-assisted balloon angioplasty was verified by angioscopy or arteriography, and all patients underwent segmental Doppler studies before discharge and during midterm follow-up extending to 30 months (mean, 11.3 months). Complications occurred in 62 (10%) patients, but only one limb amputation occurred because of a complication related to a laser-assisted balloon angioplasty. Overall, 60O/o.of initially successful procedures have remained patent, but long segment ( > 7 cm) occlusions have fared poorly (25% patency at 30 months). This minimally invasive technology affords the opportunity to treat short segment ( < 7 cm) symptomatic superficial femoral artery occlusive disease with minimal risk. Initial success and midterm patency rates for appropriate lesions appear to make laser-assisted balloon angioplasty a viable adjunct in the treatment of superficial femoral artery occlusive disease. (J VAsc Suvm 1991;14:152-9.)
In the past few years laser angioplasty has progressed from a theoretic concept to a potential clinical adjunct in the treatment of patients with atherosclerotic occlusive disease. The appeal of laser angioplasty lies in its potential for use as an adjunct or alternative for patients who might otherwise not be candidates for arterial reconstructive surgery: that is, patients in poor condition with unfavorable surgical anatomy, or at the other end of the spectrum, young patients with relatively benign symptoms. Because current thermal laser delivery systems create only a small channel in the artery, balloon From Georgia Baptist Medical Center, Atlanta (Dr. Rosenthal), the Ohio Heart Institute, Youngstown (Dr. Pesa), Doctors Hospital of Jefferson, Metairie (Dr. Gottsegen), the San FranciscoHeart Institute,SetonMedicalCenter,DalyCity (Dr. Crew), the Vascular Institute of New Jersey, Emerson (Drs. Moss and Walsky)~ and the Department of Management, Georgia State University(Dr. Pallos), Atlanta. Reprint requests: David Rosenthal, MD, 315 Blvd. N.E., Suite 412, Atlanta, GA 30312. 24/1/29238 152
angioplasty appears necessary to dilate any residual stenosis, thereby allowing sufficient blood flow for symptom relief. 1-2 The purpose of this multicenter study is to evaluate the efficacy, safety, and midterm benefits of thermal laser-assisted balloon angioplasty (LABA) of the superficial femoral artery (SFA). MATERIAL AND METHODS Between September 1986 and January 1989, 584 patients underwent 602 SFA thermal LABA procedures. Seventy-two SFAs were treated at Georgia Baptist Medical Center, Atlanta, Ga., 257 at Ohio Heart Institute, Youngstown, Ohio, 172 at Doctor's Hospital of Jefferson, Metairie, La., 67 at San Francisco Heart Institute, Daly City, Calif., and 34 at the Vascular Institute of New Jersey, Emerson, N.J. Three hundred eighty-two patients were men, and the mean age of all patients was 68 years (range, 37 to 82 years). Three hundred ninety-seven patients (66%) were cigarette smokers, 319 (53%) had coronary artery disease, 307 (51%)(51%) had hy-
Volume 14 Number 2 August 1991
pertension, and 138 (23%) patients had diabetes mellitus. The indications for LABA were intermittent claudication in 439 (73%), rest pain in 115 (19%), and gangrene in 48 (8%) of the 602 limbs treated. Two hundred ninety-two (49%) procedures were performed for multifocal stenotic disease of the SFA ( > 80% arteriographic diameter reduction), 258 for occlusion of the SFA, and 52 for both SFA stenoses and occlusion. Stenotic lesions were classified as < 3 cm, 4 to 7 cm, or > 7 cm in length (Table I). Two hundred eleven LABA procedures were performed by femoral artery cutdown, and 391 were performed via percutaneous arterial puncture. An 8.5F introducer sheath was placed into the superficial femoral or common femoral artery. Under fluoroscopic control, intraoperative arteriography demonstrated the location and extent of the arterial lesion, and a 0.035 inch metallic guide wire was passed to or through the occlusion, whenever possible. If the guide wire initially traversed the lesion, laser angioplasty was commenced with a 2.5 mm probe (Laserprobe; Trimedyne, Inc., Tustin, Cali£). If, however, the lesion could not be crossed with a guide wire, a 2 mm or 2.5 mm Laserprobe was used to create a channel through which the 0.035 inch guide wire could then be passed. Seventy percent (377/538) of the procedures were performed over a guide wire: 40% (87/218) were for occluded, 92% (256/278) for stenotic, and 80% (34/42) for both stenotic and occluded successfully treated SFAs. Five- or 10-second pulses of 8 to 12 W of laser energy from a continuous-wave laser energy source (Trimedyne Inc.) were then delivered, and the Laserprobe was advanced through the lesion with a continuous motion. Repeat arteriography was performed to determine the luminal diameter produced by the Laserprobe and to evaluate distal vessels for possible embolism. The arterial segment was then dilated by conventional balloon angioplasty followed by angioscopy or arteriography to document arterial patency. Laser-assisted balloon angioplastT was deemed successful if the ankle brachial index (ABI) increased by 0.25. During follow-up (range, 1 to 30 months; mean, 11.3 months), SFA patency was assessed by segmental Doppler studies. Laser-assisted balloon angioplasty was considered failed when hemodynamic information indicated closure (ABI < 0.15 of the highest postoperative index). This drop in ABI, however, may be due to progression of disease remote from the LABA site. After LABA the patients were discharged on a regimen of 325 nag aspirin daily. All patients were followed up by office visits
Laser angioplasty of superficial femoral artery
153
Table I. Study group Lesion length Indication (n = 602) SFA Stenoses (292) SFA Occlusions (258) SFA Stenosis and occlusion (52)
< 3 4-7 cm 64 53 3
75 106 18
> 7 cm 153 99 31
every 3 months during the first year and semiannually thereafter. Statistical analysis was performed by the actuarial life-table method to determine patency rates over time.3 RESULTS Laser-assisted balloon angioplasty successfully recanalized 84% (218 of 258) of occludcd SFAs (Table II). This technique also enlarged the luminal diameter of 95% (278 of 292) of stenotic vessels, so that less than 20% residual stenosis remained (Table III). With the use of LABA 80% (42 of 52) of both stenotic and occluded arteries were successfully treated (Table IV). This yielded an overall initial angiographdc success rate of 89% (538 of 602), and there was no significant difference in results between centers. Laser-assisted balloon angioplasty was unsuccessful in 64 (11%) SFAs. Complications related to LABA occurred in 10% (62) of patients and were most frequently noted in heavily calcified, long segment ocduded arteries (Table V). Perforation, the most common complication, occurred in 5% (31) of patients. Six perforations resulted in bleeding that required surgical repair, but the other 25 perforations were inconsequential, and the procedures were successful. After 18 SFA thromboses, only eight remained patent, whereas dissection in seven SFAs necessitated operation in four, with three remaining patent. Embolization occurred in six patients, four underwent thromboembolectomy, but only two remained patent. Because of a thromboembolic complication, operation was necessary in 4% (24) of patients and consisted of above-knee femoropopliteal bypass (14), arterial repair (6), or thromboembolectomy (4). In the entire series only one limb amputation was necessary as a result of a complication related to LABA. This was due to an SFA-popliteal dissection, which resulted in an embolic "shower" to poor quality tibial run-off vessels in a diabetic patient. In follow-up extending to 30 months (mean, 11.3 months; range, 1 to 30 months), 60% of arteries have remained patent, and the patients have remained asymptomatic with improved Doppler indexes
154
Journal of VASCULAR SURGERY
Rosenthal et al.
Table II. Life-table analysis of SFA occlusions having LABA Interval (mo)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
0-0 0-6 6-12 12-18 18-24 24-30
258 218 178 136 117 62
0 19 26 11 18 3
40 21 16 8 29 30
Interval patency rate (%)
CumulatDe patency (%)
Standard error (%)
100 89.9 90.3 93.8 73.1 50.4
100 90.3 87.5 79.0 74.2 54.2
0.0 1.6 2.3 3.1 3.4 4.6
Interval patency rate (%)
Cumulative patency (%)
Standard error (%)
100 92.7 85.9 83.9 79.6 71.9
0.0 1.4 2.0
Table III. Life-table analysis of SFA stenoses having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
0-0 0-6 6-12 12-18 18-24 24-30
292 284 247 214 192 157
0 17 28 12 20 24
14 20 5 lO 15 23
100 92.7 97.6 94.8 90.4 79.1
2.2 2.5 3.0
Table IV. Life-table analysis of both SFA stenoses and occlusions having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
Interval patency rate
Cumulative patency (%)
Standard error (%)
0-0 0-6 6-i2 12-18
52 42 29 21
0 3 6 4
I0 10 2 11
1.000 .75 .92 .4I
I00 75 57 52
0.0 5.7 5.7 7.8
(0.25 _+ 20) (Table VI, Fig. 1). Sixty-four arteries could not be recanalized and were considered initial failures. Two hundred other LABA sites thrombosed during late follow-up, and 137 of these patients underwent above-knee femoropopliteal bypass. One hundred sixteen (85%) of these 137 patients had recurrence of claudication symptoms after failed LABA; more severe symptoms developed in 21 patients (15%), however, after failed LABA (i.e., claudication symptoms developed into rest pain symptoms when the SFA reoccluded). After late failure in patients in whom the initial indication for LABA was limb salvage, 42 in situ femoropopliteal/tibial bypasses were performed for recurrence of limb salvage symptoms. Nine patients had below-knee amputations after late LABA failure; however, these patients were not deemed surgical candidates because of absent tibial runoff when LABA was initially performed for limb salvage. Midterm ( > 30 days) patency was also evaluated in relation to the type of lesion, that is, occlusion (Table II, Fig. 2) versus stenosis (Table III, Fig. 2) or both stenosis and occlusion (Table IV, Fig. 2). In
general, stenosed vessels (Table VII, Fig. 3) remained patent better than occluded vessels (Table VIII, Fig. 4), and short lesions ( < 3 cm) for both SFA stenoses and occlusions remained patent better than longer lesions ( > 7 cm), (Figs. 3 and 4). DISCUSSION The role and benefits of thermal LABA with hot tip laser probe remains controversial. The objective of this multicenter study was to evaluate the safety, efficacy, and midterm results of SFA thermal LABA. Initial cfinical results with thermal LABA suggest that it is a safe technique. 1"2"4's In this review the complication rate associated with LABA was 10% (62 patients), which is similar to other reported rates for femoral LABA. 6-9 Indeed, only one limb amputation occurred as the result ofa LABA complication. This was in a diabetic patient who had an SFApopliteal dissection and subsequent "trashing" of poor quality tibial run-off vessels. Late occlusion of the LABA site did not result in limb loss nor compromise alternative reconstructive operations, because only a short scgment of artery
Volume 14 Number 2 August 1991
Laser angioplas~y of superficialfemoral artery 155
602
100~___ 80 " ~ ' " ~ " " ~ " ~ = ~
.'~RR
-
309
I.-
z60 I.U
o
uJ 4O Q. 20
°0
12
18
24
30
MONTHS Fig. 1. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties. Numbers at intervals indicate arteries at risk.
1O0 r ~ , = 2 ~ I
I I-- 80
oo
~ \
'
o Stenoses • Occlusions • Sten. & Occl.
.
~ a ao
~ ~
1'2
1'8
--
2'4
ab
MONTHS Fig. 2. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties performed for stenoses, occlusions, or stenoses and occlusion. Numbers at intervals indicate arteries at risk. around the angioplasty site thromboses, and the abundant collateral network appears to protect the remaining artery. Nine patients had limb amputations during late follow-up after LABA site thrombosis. These patients, however, had severe infrapopliteal occlusive disease in association with an SFA lesion and were not deemed operative candidates at the time LABA was performed for limb salvage, because no distal tibial vessels were identified to which an in situ vein graft could be placed. LABA was offered as a last hope of salvaging the limb by augmenting collateral flow. During foUow-up, 200 LABAs occluded, and 137 patients underwent above-knee femoropopliteal bypass. One hundred sixteen (85%) of the 137 patients had recurrence of the same claudication symptoms that were present when LABA was performed. Twenty-one patients
Table V. Complications related to LABA (N -- 62) % (No.) Perforation Thrombosis Dissection Embolization
5 3 1 1
(31) (18) (7) (6)
(15%) who required femoropopliteal bypass, however, had worsening of :symptoms when the LABA site reocduded. At repeat arteriography, 10 of these 15 patients had longer segment occlusions than were present when the initial LABA was performed, and five patients had worsening of distal occlusive disease. Another 42 patients had in sire femoro-
Journal of VASCULAR SURGERY
156 Rosenthal et al.
100
I-Z LU
O 80 i"II.U 0,.
• •
6O
0
< 3cm 4-7 cm >7cm
do
1'2
1'8
2'4
a'0
MONTHS
Fig. 3. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties performed for stenoses by lesion length. 100
80 IZ LU
0n-6 0 ILl 13.
• •
40
7cm
,,
2O
I'2
o
1'8
2'4
3'0
MONTHS
Fig. 4. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties performed for occlusions by lesion length. Table VI. Life-table analysis of SFAs having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
0-0 0-6 6-12 12-18 18-24 24-30
602 538 448 365 309 227
0 39 60 27 38 27
64 51 23 29 44 53
popliteal/tibial bypasses performed for recurrence of limb salvage symptoms when the LABA site occluded. The initial indication for LABA in these 42 patients was limb salvage. In general, thrombosis of the LABA site caused the recurrence of symptoms, not limb loss. As with all endovascular (and surgical) techniques, complication rates are directly proportional to the operator's experience. In experienced
Interval patency rate (%) 100 90.2 94.5 91.7 84.8 75.1
Cumulative patency (%)
Standard error (%)
100 90.2 81.3 76.8 70.5 59.8
0.0 1.2 1.6 1.9 2.1 2.5
hands LABA of the SFA appears to be a safe procedure. The overall 30-month cumulative patency rate of 60% in this series is equal to or greater than that reported for conventional SFA balloon angioplasty when evaluated on the basis of type and length of lesion, as well as on the method of data analysis. For example, the 12-month patency rates with short ( < 3
Voiume 14 Number 2 August 1991
Laser angioplasty of superficialfemoral artery 157
Table VII. Life-table analysis of SFA stenoses having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
< 3 cm 0-0 0-6 6-12 12-18 18-24 24-30
64 63 56 45 37 27
0 5 11 6 7 7
0-0 0-6 6-12 12-18 18-24 24-30
75 72 60 47 41 32
> 7 cm 0-0 0-6 6-12 12-18 18-24 24-30
153 143 125 116 108 92
No. of failed LABAs
Interval patency rate (%)
Cumulative patency (%)
Standard error (%)
1 2 0 2 3 5
100 96.6 100 95.2 91.0 78.7
I00 98.4 95.1 95.1 82.5
0.0 1.5 2.7 3.1 4.5 6.6
0 6 12 3 7 8
3 6 1 3 2 5
96,0 91.3 98.1 93.4 94.6 82.1
100 96.0 87.6 86.0 80.3 76,0
0.0 2.2 3.9 4.6 5.5 6.5
0 6 5 3 6 9
10 12 4 5 10 13
93.0 91.4 96.7 95.6 90.4 98.8
100 93.4 85.4 81.7 78.1 70.6
0.0 1.9 2.9 3.2 3.5 3,9
Interval patency rate (%)
Cumulative patency (%)
Standard error (%)
3.2 4.7 6.4 7.8 10.7
90.6
4-7 cm
Table VIII. Life-table analysis of SFA occlusions having LABA Interval (mo)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
< 3 cm 0-0 0-6 6-12 12-18 18-24 24-30
53 50 41 30 23 12
0 6 8 5 6 1
3 3 3 2 5 5
94.0 93.6 91.9 92.7 75.0 56.5
100 94.0 88.0 80.8 74.9 56.2
4-7 cm 0-0 0-6 6-12 12-18 18-24 24-30
106 91 78 64 59 45
0 7 10 3 6 2
15 6 4 2 8 15
86.0 93.1 94.5 96.8 85.7 65.9
100 85.8 75.5 73.1 62.7
0.0 3.3 4.0 4.6 4.9 5.7
>7cm 0-0 0-6 6-12 12-18 18-24 24-30
99 77 59 42 35 13
0 6 8 3 6 0
22 12 9 4 16 10
78.0 83.7 83.6 90.1 50.0 23.0
100 77.7 65.1 54.5 49.1 24.5
0.0 4.1 5.0 5.6 6.0 6.1
cm) stenoses and short occlusions in this series were 95.1% and 88.0%, respectively (Tables VII, VIII). These rates are considerably higher than those obtained in balloon angioplasty series, in which the 12-month patency rates range between 72% and 81% for stenoses and 67% and 93% for short occlusions.~°,~2 The 12-month patency rate for me-
79.9
dium length (4 to 7 cm) occlusions treated with LABA (Table VIII) was 79.9%, and the rate for occlusions longer than 7 cm, was 65.1%, both of which are better than the patency rate for occlusions longer than 3 cm treated by balloon angioplasty (Table IX). 12 Although the patency rates for occlusions longer than 3 cm appear to be better in two of
Journal of VASCULAR SURGERY
158 Rosenthal et al.
Table IX. Twelve-month patency rates for SFA LABA versus balloon angioplasty Sunoses (%)
LABA (n = 292) Balloon Angioplasty Hewcs et al. 1° (N = 50) Murray et al. ix (n = 116) Krepel et al.i2 (n = 127)
< cm
4-7 cm
95.1 85 82.4 83
> 7 cm
< 3 cm
87.6
85.4
(n = 258) 88
79.9
65.1
100 ( 3 cm)
38 23.1
(n = 41) 67 (n = 77) (n = 37)
100 85.9 50 ( > 3 cm)
68 (all occlusions)
Table X. Estimated success rates related to site of lesion ~ Site
Initial recanalization (%)
Mid SFA
70
Diffuse SFA
50-60
Occlusions (%)
Follaw-up patency (%)
60 Stenoses 70% Occlusions 50% 40%
~Values estimated from survey o f the currently available values (published and unpublished data) at 12- to i 8 - m o n t h follow-up visits.*
the balloon angioplasty series, their results are not comparable to ours because they did not consider an SFA "redilitation" for a restenosed or occluded vessel as a failure. I°'I~ Only a randomized prospective trial comparing LABA and balloon angioplasty alone can resolve this controversy. Finally, these and virtually all published results for balloon angioplasty are based on only initially successful angioplasties; inability to cross a lesion or to reduce the angiographic percentage of stenosis is considered a failure, and these procedures are excluded from calculations of long-term patency. The results of LABA in this study are superior to those of SFA balloon angioplasty because all patients, regardless of initial success or failure, were included in the life-table analysis. One possible explanation for the higher patency rates after laser thermal angioplasty is that the laser partially removes the atheromatous lesion and leaves behind a smoother arterial surface. Undue thrombogenesis resulting from thermal injury after laser angioplasty does not seem to be a clinically significant cause of failure) Our study demonstrates that thermal LABA was best suited for the treatment of localized SFA lesions, which inherently limits the number of patients who will benefit from this procedure. The 24.5% patency rate for occlusions longer than 7 cm at 30-month follow-up was poor (Table VIII). Although the study design did not delineate the length of the 99 occlusions longer than 7 cm, data were available indicating that 65 long-term failures had occlusions
4-7 cm
> 7 cm
Table XI. Estimated success rates related to length of lesion s Length of stenoses and occlusions
Initial recanalization
Follow-up patency
(cm)
(%)
(%)
1-3 3-7 7-10 10
85-90 80 70 60
60-70 50-60 45 20-40
"Values estimated from survey o f the currently available vaiues (published and unpublished data) at 12- to 18-month follow-up visits. 8
between 10 and 18 cm. A report by Perler et al. 13 on 47 occluded SFAs treated by thermal LABA demonstrated a patency rate of only 7% at 15-month follow-up. However, 24 of the patients treated had lesions more than 7 cm in length, only small Laserprobes (1 to 2 mm diameter) with very low laser energies (2 to 8 watts) were used. In a recent overview by White and White 8 in the JOURNAL OF VASCULAR SURGERY, the patency values at 12- to 18-month follow-up for thermal LABA, were directly affected bY site and length of arterial stenosis or occlusion (Tables X, XI). These reported initial recanalization and long-term patency rates appear similar to our results. For the best long-term results, it seems a long segment SFA occlusion should be treated by femoropopliteal bypass when symptoms warrant.
This study demonstrates that LABA of the SFA is safe and efficacious. The promising midterm benefits for short segment occlusive lesions warrant further investigation. The most appropriate method to report long-term patency results of endovascular interventional techniques remains controversial. It seems logical, however, to evaluate the durability of LABA once a successful procedure has been accomplished, rather than to evaluate the operator's ability to recanalize an artery. Laser angioplasty is not the panacea many people thought it would be, and it will not revolutionize the
Volume 14 Number 2 August 1991
treatment o f lower extremity arterial occlusive disease. As experience grows and t e c h n o l o g y improves we will learn w h i c h concepts to embrace and w h i c h to disregard, b u t in this study thermal L A B A was m o s t successful in patients with claudication and short segment ( < 7 cm), noncalcific lesions. This will inherently limit the n u m b e r o f patients w h o will currently benefit f r o m flais procedure, but to m o r e t h o r o u g h l y understand and evaluate the role o f L A B A in the treatment o f SFA occlusive disease, a randomized, prospective trial c o m p a r i n g no treatment, balloon angioplasty, and L A B A m u s t be done. Until then, L A B A offers the benefits o f a minimally invasive treatment technique, but careful patient selection is necessary to ensure g o o d results with minimal risks. REFERENCES
1. Seeger IA, Abela GS, Silverman SH. Initial results of laser recanalization in lower extremity arterial reconstruction. J Vase SURG 1989;9:10-6. 2. Sanborn TA, Greenfield AJ, Guben JK, et al. Human percutaneous and intraoperative laser thermal angioplasty: initial cfinical results as an adjunct to balloon angioplasty: I VAsc SURG I987;5:83-90. 3. Dickson WJ, Brown MB, Engleman L, et al. DMDP Statistical Software. Regents University of California, 1985. 4. Cumberland DC, Sanborn TA, Taylor DI, et al. Percutaneous
Laser angioplasty of superficial femoral artery 159
5. 6.
7. 8. 9. 10. 11. 12. 13.
laser thermal angioplasty: initial clinical results with a laserprobe in total peripheral artery occlusions. Lancet 1986;1: 1457-9. Kateen BT, Kaplan JD, Schwarten DM, et al. Complications of "Hot Tip" laser assisted angioplasty [Abstract]. Circulation 1988;78(suppl. II):I1-417. Thomas I-IM, Siragusa V, Bowers JA, et al. Percutaneous laser assisted balloon angioplasty of lower extremity arterial disease in a free standing laboratory. Diagn Ther 1989;16:216-23. Criado FJ, Queral LA, Patten P, et al. Laser angioplasty in the lower extremities: an early surgical experience. J VASCSURG 1990;11:532-5. White RA, White GH. Laser thermal probe recanalization of occluded arteries. J VASCSUING1989;9:598-608. Leachman DR. Hot tip laser angioplasty. A review of the Texas Heart Institute experience. Tex Heart Inst J 1989;16: 207-15. Hewes RC, White R.I, Murray RR, et al. Long-term results of superficial femoral artery angioptasty. MR 1986;146: 1025-9. Murray RR Jr, Hewes RC, White RI Jr, et al. Long-segment femoropopliteal stenoses: is angioplasty a boon or a bust? Radiology 1987;162:473-6. Krepel VM, van Andel GI, van Erp WFM, et al. Percutaneous transluminal angioplasty of the femoropopliteal artery: initial and long-term results. Radiology 1985;156:325-8. Perler BA, Osterman FA, White RI, et al. Percutaneous laser probe femoropopliteal angioplasty: a preliminary experience. J VASe SURG I989;i0:351-7.
Submitted Nov. 13, 1990; accepted March 4, 1991.
City, Calif.,
and Emerson, N.J. A multicenter review of 602 procedures was performed to evaluate the effects of thermal laser-assisted balloon angioplasty on the superficial femoral artery. Four hundred thirty-nine (73%) patients underwent laser-assisted balloon angioplasty for claudication, and 163 (27%) underwent the procedure for limb salvage. Two hundred ninety-two laser-assisted balloon angioplasty procedures were performed for multifocal stenotic disease (> 80%) diameter reduction), 258 for total occlusion, and 52 procedures for both superficial femoral artery stenosis and occlusion. The initial recanalization rate was 89% (538/602) depending on the length of the lesion. Success of laser-assisted balloon angioplasty was verified by angioscopy or arteriography, and all patients underwent segmental Doppler studies before discharge and during midterm follow-up extending to 30 months (mean, 11.3 months). Complications occurred in 62 (10%) patients, but only one limb amputation occurred because of a complication related to a laser-assisted balloon angioplasty. Overall, 60O/o.of initially successful procedures have remained patent, but long segment ( > 7 cm) occlusions have fared poorly (25% patency at 30 months). This minimally invasive technology affords the opportunity to treat short segment ( < 7 cm) symptomatic superficial femoral artery occlusive disease with minimal risk. Initial success and midterm patency rates for appropriate lesions appear to make laser-assisted balloon angioplasty a viable adjunct in the treatment of superficial femoral artery occlusive disease. (J VAsc Suvm 1991;14:152-9.)
In the past few years laser angioplasty has progressed from a theoretic concept to a potential clinical adjunct in the treatment of patients with atherosclerotic occlusive disease. The appeal of laser angioplasty lies in its potential for use as an adjunct or alternative for patients who might otherwise not be candidates for arterial reconstructive surgery: that is, patients in poor condition with unfavorable surgical anatomy, or at the other end of the spectrum, young patients with relatively benign symptoms. Because current thermal laser delivery systems create only a small channel in the artery, balloon From Georgia Baptist Medical Center, Atlanta (Dr. Rosenthal), the Ohio Heart Institute, Youngstown (Dr. Pesa), Doctors Hospital of Jefferson, Metairie (Dr. Gottsegen), the San FranciscoHeart Institute,SetonMedicalCenter,DalyCity (Dr. Crew), the Vascular Institute of New Jersey, Emerson (Drs. Moss and Walsky)~ and the Department of Management, Georgia State University(Dr. Pallos), Atlanta. Reprint requests: David Rosenthal, MD, 315 Blvd. N.E., Suite 412, Atlanta, GA 30312. 24/1/29238 152
angioplasty appears necessary to dilate any residual stenosis, thereby allowing sufficient blood flow for symptom relief. 1-2 The purpose of this multicenter study is to evaluate the efficacy, safety, and midterm benefits of thermal laser-assisted balloon angioplasty (LABA) of the superficial femoral artery (SFA). MATERIAL AND METHODS Between September 1986 and January 1989, 584 patients underwent 602 SFA thermal LABA procedures. Seventy-two SFAs were treated at Georgia Baptist Medical Center, Atlanta, Ga., 257 at Ohio Heart Institute, Youngstown, Ohio, 172 at Doctor's Hospital of Jefferson, Metairie, La., 67 at San Francisco Heart Institute, Daly City, Calif., and 34 at the Vascular Institute of New Jersey, Emerson, N.J. Three hundred eighty-two patients were men, and the mean age of all patients was 68 years (range, 37 to 82 years). Three hundred ninety-seven patients (66%) were cigarette smokers, 319 (53%) had coronary artery disease, 307 (51%)(51%) had hy-
Volume 14 Number 2 August 1991
pertension, and 138 (23%) patients had diabetes mellitus. The indications for LABA were intermittent claudication in 439 (73%), rest pain in 115 (19%), and gangrene in 48 (8%) of the 602 limbs treated. Two hundred ninety-two (49%) procedures were performed for multifocal stenotic disease of the SFA ( > 80% arteriographic diameter reduction), 258 for occlusion of the SFA, and 52 for both SFA stenoses and occlusion. Stenotic lesions were classified as < 3 cm, 4 to 7 cm, or > 7 cm in length (Table I). Two hundred eleven LABA procedures were performed by femoral artery cutdown, and 391 were performed via percutaneous arterial puncture. An 8.5F introducer sheath was placed into the superficial femoral or common femoral artery. Under fluoroscopic control, intraoperative arteriography demonstrated the location and extent of the arterial lesion, and a 0.035 inch metallic guide wire was passed to or through the occlusion, whenever possible. If the guide wire initially traversed the lesion, laser angioplasty was commenced with a 2.5 mm probe (Laserprobe; Trimedyne, Inc., Tustin, Cali£). If, however, the lesion could not be crossed with a guide wire, a 2 mm or 2.5 mm Laserprobe was used to create a channel through which the 0.035 inch guide wire could then be passed. Seventy percent (377/538) of the procedures were performed over a guide wire: 40% (87/218) were for occluded, 92% (256/278) for stenotic, and 80% (34/42) for both stenotic and occluded successfully treated SFAs. Five- or 10-second pulses of 8 to 12 W of laser energy from a continuous-wave laser energy source (Trimedyne Inc.) were then delivered, and the Laserprobe was advanced through the lesion with a continuous motion. Repeat arteriography was performed to determine the luminal diameter produced by the Laserprobe and to evaluate distal vessels for possible embolism. The arterial segment was then dilated by conventional balloon angioplasty followed by angioscopy or arteriography to document arterial patency. Laser-assisted balloon angioplastT was deemed successful if the ankle brachial index (ABI) increased by 0.25. During follow-up (range, 1 to 30 months; mean, 11.3 months), SFA patency was assessed by segmental Doppler studies. Laser-assisted balloon angioplasty was considered failed when hemodynamic information indicated closure (ABI < 0.15 of the highest postoperative index). This drop in ABI, however, may be due to progression of disease remote from the LABA site. After LABA the patients were discharged on a regimen of 325 nag aspirin daily. All patients were followed up by office visits
Laser angioplasty of superficial femoral artery
153
Table I. Study group Lesion length Indication (n = 602) SFA Stenoses (292) SFA Occlusions (258) SFA Stenosis and occlusion (52)
< 3 4-7 cm 64 53 3
75 106 18
> 7 cm 153 99 31
every 3 months during the first year and semiannually thereafter. Statistical analysis was performed by the actuarial life-table method to determine patency rates over time.3 RESULTS Laser-assisted balloon angioplasty successfully recanalized 84% (218 of 258) of occludcd SFAs (Table II). This technique also enlarged the luminal diameter of 95% (278 of 292) of stenotic vessels, so that less than 20% residual stenosis remained (Table III). With the use of LABA 80% (42 of 52) of both stenotic and occluded arteries were successfully treated (Table IV). This yielded an overall initial angiographdc success rate of 89% (538 of 602), and there was no significant difference in results between centers. Laser-assisted balloon angioplasty was unsuccessful in 64 (11%) SFAs. Complications related to LABA occurred in 10% (62) of patients and were most frequently noted in heavily calcified, long segment ocduded arteries (Table V). Perforation, the most common complication, occurred in 5% (31) of patients. Six perforations resulted in bleeding that required surgical repair, but the other 25 perforations were inconsequential, and the procedures were successful. After 18 SFA thromboses, only eight remained patent, whereas dissection in seven SFAs necessitated operation in four, with three remaining patent. Embolization occurred in six patients, four underwent thromboembolectomy, but only two remained patent. Because of a thromboembolic complication, operation was necessary in 4% (24) of patients and consisted of above-knee femoropopliteal bypass (14), arterial repair (6), or thromboembolectomy (4). In the entire series only one limb amputation was necessary as a result of a complication related to LABA. This was due to an SFA-popliteal dissection, which resulted in an embolic "shower" to poor quality tibial run-off vessels in a diabetic patient. In follow-up extending to 30 months (mean, 11.3 months; range, 1 to 30 months), 60% of arteries have remained patent, and the patients have remained asymptomatic with improved Doppler indexes
154
Journal of VASCULAR SURGERY
Rosenthal et al.
Table II. Life-table analysis of SFA occlusions having LABA Interval (mo)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
0-0 0-6 6-12 12-18 18-24 24-30
258 218 178 136 117 62
0 19 26 11 18 3
40 21 16 8 29 30
Interval patency rate (%)
CumulatDe patency (%)
Standard error (%)
100 89.9 90.3 93.8 73.1 50.4
100 90.3 87.5 79.0 74.2 54.2
0.0 1.6 2.3 3.1 3.4 4.6
Interval patency rate (%)
Cumulative patency (%)
Standard error (%)
100 92.7 85.9 83.9 79.6 71.9
0.0 1.4 2.0
Table III. Life-table analysis of SFA stenoses having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
0-0 0-6 6-12 12-18 18-24 24-30
292 284 247 214 192 157
0 17 28 12 20 24
14 20 5 lO 15 23
100 92.7 97.6 94.8 90.4 79.1
2.2 2.5 3.0
Table IV. Life-table analysis of both SFA stenoses and occlusions having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
Interval patency rate
Cumulative patency (%)
Standard error (%)
0-0 0-6 6-i2 12-18
52 42 29 21
0 3 6 4
I0 10 2 11
1.000 .75 .92 .4I
I00 75 57 52
0.0 5.7 5.7 7.8
(0.25 _+ 20) (Table VI, Fig. 1). Sixty-four arteries could not be recanalized and were considered initial failures. Two hundred other LABA sites thrombosed during late follow-up, and 137 of these patients underwent above-knee femoropopliteal bypass. One hundred sixteen (85%) of these 137 patients had recurrence of claudication symptoms after failed LABA; more severe symptoms developed in 21 patients (15%), however, after failed LABA (i.e., claudication symptoms developed into rest pain symptoms when the SFA reoccluded). After late failure in patients in whom the initial indication for LABA was limb salvage, 42 in situ femoropopliteal/tibial bypasses were performed for recurrence of limb salvage symptoms. Nine patients had below-knee amputations after late LABA failure; however, these patients were not deemed surgical candidates because of absent tibial runoff when LABA was initially performed for limb salvage. Midterm ( > 30 days) patency was also evaluated in relation to the type of lesion, that is, occlusion (Table II, Fig. 2) versus stenosis (Table III, Fig. 2) or both stenosis and occlusion (Table IV, Fig. 2). In
general, stenosed vessels (Table VII, Fig. 3) remained patent better than occluded vessels (Table VIII, Fig. 4), and short lesions ( < 3 cm) for both SFA stenoses and occlusions remained patent better than longer lesions ( > 7 cm), (Figs. 3 and 4). DISCUSSION The role and benefits of thermal LABA with hot tip laser probe remains controversial. The objective of this multicenter study was to evaluate the safety, efficacy, and midterm results of SFA thermal LABA. Initial cfinical results with thermal LABA suggest that it is a safe technique. 1"2"4's In this review the complication rate associated with LABA was 10% (62 patients), which is similar to other reported rates for femoral LABA. 6-9 Indeed, only one limb amputation occurred as the result ofa LABA complication. This was in a diabetic patient who had an SFApopliteal dissection and subsequent "trashing" of poor quality tibial run-off vessels. Late occlusion of the LABA site did not result in limb loss nor compromise alternative reconstructive operations, because only a short scgment of artery
Volume 14 Number 2 August 1991
Laser angioplas~y of superficialfemoral artery 155
602
100~___ 80 " ~ ' " ~ " " ~ " ~ = ~
.'~RR
-
309
I.-
z60 I.U
o
uJ 4O Q. 20
°0
12
18
24
30
MONTHS Fig. 1. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties. Numbers at intervals indicate arteries at risk.
1O0 r ~ , = 2 ~ I
I I-- 80
oo
~ \
'
o Stenoses • Occlusions • Sten. & Occl.
.
~ a ao
~ ~
1'2
1'8
--
2'4
ab
MONTHS Fig. 2. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties performed for stenoses, occlusions, or stenoses and occlusion. Numbers at intervals indicate arteries at risk. around the angioplasty site thromboses, and the abundant collateral network appears to protect the remaining artery. Nine patients had limb amputations during late follow-up after LABA site thrombosis. These patients, however, had severe infrapopliteal occlusive disease in association with an SFA lesion and were not deemed operative candidates at the time LABA was performed for limb salvage, because no distal tibial vessels were identified to which an in situ vein graft could be placed. LABA was offered as a last hope of salvaging the limb by augmenting collateral flow. During foUow-up, 200 LABAs occluded, and 137 patients underwent above-knee femoropopliteal bypass. One hundred sixteen (85%) of the 137 patients had recurrence of the same claudication symptoms that were present when LABA was performed. Twenty-one patients
Table V. Complications related to LABA (N -- 62) % (No.) Perforation Thrombosis Dissection Embolization
5 3 1 1
(31) (18) (7) (6)
(15%) who required femoropopliteal bypass, however, had worsening of :symptoms when the LABA site reocduded. At repeat arteriography, 10 of these 15 patients had longer segment occlusions than were present when the initial LABA was performed, and five patients had worsening of distal occlusive disease. Another 42 patients had in sire femoro-
Journal of VASCULAR SURGERY
156 Rosenthal et al.
100
I-Z LU
O 80 i"II.U 0,.
• •
6O
0
< 3cm 4-7 cm >7cm
do
1'2
1'8
2'4
a'0
MONTHS
Fig. 3. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties performed for stenoses by lesion length. 100
80 IZ LU
0n-6 0 ILl 13.
• •
40
7cm
,,
2O
I'2
o
1'8
2'4
3'0
MONTHS
Fig. 4. Cumulative patency of superficial femoral artery laser-assisted balloon angioplasties performed for occlusions by lesion length. Table VI. Life-table analysis of SFAs having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
0-0 0-6 6-12 12-18 18-24 24-30
602 538 448 365 309 227
0 39 60 27 38 27
64 51 23 29 44 53
popliteal/tibial bypasses performed for recurrence of limb salvage symptoms when the LABA site occluded. The initial indication for LABA in these 42 patients was limb salvage. In general, thrombosis of the LABA site caused the recurrence of symptoms, not limb loss. As with all endovascular (and surgical) techniques, complication rates are directly proportional to the operator's experience. In experienced
Interval patency rate (%) 100 90.2 94.5 91.7 84.8 75.1
Cumulative patency (%)
Standard error (%)
100 90.2 81.3 76.8 70.5 59.8
0.0 1.2 1.6 1.9 2.1 2.5
hands LABA of the SFA appears to be a safe procedure. The overall 30-month cumulative patency rate of 60% in this series is equal to or greater than that reported for conventional SFA balloon angioplasty when evaluated on the basis of type and length of lesion, as well as on the method of data analysis. For example, the 12-month patency rates with short ( < 3
Voiume 14 Number 2 August 1991
Laser angioplasty of superficialfemoral artery 157
Table VII. Life-table analysis of SFA stenoses having LABA Interval (too)
No. of SFAs at risk at start
Lost to follow-up
< 3 cm 0-0 0-6 6-12 12-18 18-24 24-30
64 63 56 45 37 27
0 5 11 6 7 7
0-0 0-6 6-12 12-18 18-24 24-30
75 72 60 47 41 32
> 7 cm 0-0 0-6 6-12 12-18 18-24 24-30
153 143 125 116 108 92
No. of failed LABAs
Interval patency rate (%)
Cumulative patency (%)
Standard error (%)
1 2 0 2 3 5
100 96.6 100 95.2 91.0 78.7
I00 98.4 95.1 95.1 82.5
0.0 1.5 2.7 3.1 4.5 6.6
0 6 12 3 7 8
3 6 1 3 2 5
96,0 91.3 98.1 93.4 94.6 82.1
100 96.0 87.6 86.0 80.3 76,0
0.0 2.2 3.9 4.6 5.5 6.5
0 6 5 3 6 9
10 12 4 5 10 13
93.0 91.4 96.7 95.6 90.4 98.8
100 93.4 85.4 81.7 78.1 70.6
0.0 1.9 2.9 3.2 3.5 3,9
Interval patency rate (%)
Cumulative patency (%)
Standard error (%)
3.2 4.7 6.4 7.8 10.7
90.6
4-7 cm
Table VIII. Life-table analysis of SFA occlusions having LABA Interval (mo)
No. of SFAs at risk at start
Lost to follow-up
No. of failed LABAs
< 3 cm 0-0 0-6 6-12 12-18 18-24 24-30
53 50 41 30 23 12
0 6 8 5 6 1
3 3 3 2 5 5
94.0 93.6 91.9 92.7 75.0 56.5
100 94.0 88.0 80.8 74.9 56.2
4-7 cm 0-0 0-6 6-12 12-18 18-24 24-30
106 91 78 64 59 45
0 7 10 3 6 2
15 6 4 2 8 15
86.0 93.1 94.5 96.8 85.7 65.9
100 85.8 75.5 73.1 62.7
0.0 3.3 4.0 4.6 4.9 5.7
>7cm 0-0 0-6 6-12 12-18 18-24 24-30
99 77 59 42 35 13
0 6 8 3 6 0
22 12 9 4 16 10
78.0 83.7 83.6 90.1 50.0 23.0
100 77.7 65.1 54.5 49.1 24.5
0.0 4.1 5.0 5.6 6.0 6.1
cm) stenoses and short occlusions in this series were 95.1% and 88.0%, respectively (Tables VII, VIII). These rates are considerably higher than those obtained in balloon angioplasty series, in which the 12-month patency rates range between 72% and 81% for stenoses and 67% and 93% for short occlusions.~°,~2 The 12-month patency rate for me-
79.9
dium length (4 to 7 cm) occlusions treated with LABA (Table VIII) was 79.9%, and the rate for occlusions longer than 7 cm, was 65.1%, both of which are better than the patency rate for occlusions longer than 3 cm treated by balloon angioplasty (Table IX). 12 Although the patency rates for occlusions longer than 3 cm appear to be better in two of
Journal of VASCULAR SURGERY
158 Rosenthal et al.
Table IX. Twelve-month patency rates for SFA LABA versus balloon angioplasty Sunoses (%)
LABA (n = 292) Balloon Angioplasty Hewcs et al. 1° (N = 50) Murray et al. ix (n = 116) Krepel et al.i2 (n = 127)
< cm
4-7 cm
95.1 85 82.4 83
> 7 cm
< 3 cm
87.6
85.4
(n = 258) 88
79.9
65.1
100 ( 3 cm)
38 23.1
(n = 41) 67 (n = 77) (n = 37)
100 85.9 50 ( > 3 cm)
68 (all occlusions)
Table X. Estimated success rates related to site of lesion ~ Site
Initial recanalization (%)
Mid SFA
70
Diffuse SFA
50-60
Occlusions (%)
Follaw-up patency (%)
60 Stenoses 70% Occlusions 50% 40%
~Values estimated from survey o f the currently available values (published and unpublished data) at 12- to i 8 - m o n t h follow-up visits.*
the balloon angioplasty series, their results are not comparable to ours because they did not consider an SFA "redilitation" for a restenosed or occluded vessel as a failure. I°'I~ Only a randomized prospective trial comparing LABA and balloon angioplasty alone can resolve this controversy. Finally, these and virtually all published results for balloon angioplasty are based on only initially successful angioplasties; inability to cross a lesion or to reduce the angiographic percentage of stenosis is considered a failure, and these procedures are excluded from calculations of long-term patency. The results of LABA in this study are superior to those of SFA balloon angioplasty because all patients, regardless of initial success or failure, were included in the life-table analysis. One possible explanation for the higher patency rates after laser thermal angioplasty is that the laser partially removes the atheromatous lesion and leaves behind a smoother arterial surface. Undue thrombogenesis resulting from thermal injury after laser angioplasty does not seem to be a clinically significant cause of failure) Our study demonstrates that thermal LABA was best suited for the treatment of localized SFA lesions, which inherently limits the number of patients who will benefit from this procedure. The 24.5% patency rate for occlusions longer than 7 cm at 30-month follow-up was poor (Table VIII). Although the study design did not delineate the length of the 99 occlusions longer than 7 cm, data were available indicating that 65 long-term failures had occlusions
4-7 cm
> 7 cm
Table XI. Estimated success rates related to length of lesion s Length of stenoses and occlusions
Initial recanalization
Follow-up patency
(cm)
(%)
(%)
1-3 3-7 7-10 10
85-90 80 70 60
60-70 50-60 45 20-40
"Values estimated from survey o f the currently available vaiues (published and unpublished data) at 12- to 18-month follow-up visits. 8
between 10 and 18 cm. A report by Perler et al. 13 on 47 occluded SFAs treated by thermal LABA demonstrated a patency rate of only 7% at 15-month follow-up. However, 24 of the patients treated had lesions more than 7 cm in length, only small Laserprobes (1 to 2 mm diameter) with very low laser energies (2 to 8 watts) were used. In a recent overview by White and White 8 in the JOURNAL OF VASCULAR SURGERY, the patency values at 12- to 18-month follow-up for thermal LABA, were directly affected bY site and length of arterial stenosis or occlusion (Tables X, XI). These reported initial recanalization and long-term patency rates appear similar to our results. For the best long-term results, it seems a long segment SFA occlusion should be treated by femoropopliteal bypass when symptoms warrant.
This study demonstrates that LABA of the SFA is safe and efficacious. The promising midterm benefits for short segment occlusive lesions warrant further investigation. The most appropriate method to report long-term patency results of endovascular interventional techniques remains controversial. It seems logical, however, to evaluate the durability of LABA once a successful procedure has been accomplished, rather than to evaluate the operator's ability to recanalize an artery. Laser angioplasty is not the panacea many people thought it would be, and it will not revolutionize the
Volume 14 Number 2 August 1991
treatment o f lower extremity arterial occlusive disease. As experience grows and t e c h n o l o g y improves we will learn w h i c h concepts to embrace and w h i c h to disregard, b u t in this study thermal L A B A was m o s t successful in patients with claudication and short segment ( < 7 cm), noncalcific lesions. This will inherently limit the n u m b e r o f patients w h o will currently benefit f r o m flais procedure, but to m o r e t h o r o u g h l y understand and evaluate the role o f L A B A in the treatment o f SFA occlusive disease, a randomized, prospective trial c o m p a r i n g no treatment, balloon angioplasty, and L A B A m u s t be done. Until then, L A B A offers the benefits o f a minimally invasive treatment technique, but careful patient selection is necessary to ensure g o o d results with minimal risks. REFERENCES
1. Seeger IA, Abela GS, Silverman SH. Initial results of laser recanalization in lower extremity arterial reconstruction. J Vase SURG 1989;9:10-6. 2. Sanborn TA, Greenfield AJ, Guben JK, et al. Human percutaneous and intraoperative laser thermal angioplasty: initial cfinical results as an adjunct to balloon angioplasty: I VAsc SURG I987;5:83-90. 3. Dickson WJ, Brown MB, Engleman L, et al. DMDP Statistical Software. Regents University of California, 1985. 4. Cumberland DC, Sanborn TA, Taylor DI, et al. Percutaneous
Laser angioplasty of superficial femoral artery 159
5. 6.
7. 8. 9. 10. 11. 12. 13.
laser thermal angioplasty: initial clinical results with a laserprobe in total peripheral artery occlusions. Lancet 1986;1: 1457-9. Kateen BT, Kaplan JD, Schwarten DM, et al. Complications of "Hot Tip" laser assisted angioplasty [Abstract]. Circulation 1988;78(suppl. II):I1-417. Thomas I-IM, Siragusa V, Bowers JA, et al. Percutaneous laser assisted balloon angioplasty of lower extremity arterial disease in a free standing laboratory. Diagn Ther 1989;16:216-23. Criado FJ, Queral LA, Patten P, et al. Laser angioplasty in the lower extremities: an early surgical experience. J VASCSURG 1990;11:532-5. White RA, White GH. Laser thermal probe recanalization of occluded arteries. J VASCSUING1989;9:598-608. Leachman DR. Hot tip laser angioplasty. A review of the Texas Heart Institute experience. Tex Heart Inst J 1989;16: 207-15. Hewes RC, White R.I, Murray RR, et al. Long-term results of superficial femoral artery angioptasty. MR 1986;146: 1025-9. Murray RR Jr, Hewes RC, White RI Jr, et al. Long-segment femoropopliteal stenoses: is angioplasty a boon or a bust? Radiology 1987;162:473-6. Krepel VM, van Andel GI, van Erp WFM, et al. Percutaneous transluminal angioplasty of the femoropopliteal artery: initial and long-term results. Radiology 1985;156:325-8. Perler BA, Osterman FA, White RI, et al. Percutaneous laser probe femoropopliteal angioplasty: a preliminary experience. J VASe SURG I989;i0:351-7.
Submitted Nov. 13, 1990; accepted March 4, 1991.
