Interventional Peter Claus

E. Huppert, D. Claussen,

MD MD

Stephan

#{149}

H. Duda,

MD

Uwe

Helber,

#{149}

MD

#{149} Karl

Radiology MD

R. Karsch,

Comparison ofPulsed Laser-assisted Angioplasty and Balloon Angioplasty in Femoropopliteal Artery Occlusions’ The authors performed a prospective, comparative study of 96 patients (age, 41-87 years) with femoropopliteal artery occlusions. Laser-assisted angioplasty was performed in 64 patients with 9- and 7-F over-the-wire

multifiber catheters. Supplemental balloon dilation was performed after laser angioplasty. Thirty-two patients underwent excimer laser angioplasty (ELA), and 32 underwent pulsed dye laser angioplasty (DLA). The remaining 32 patients underwent conventional balloon angioplasty (BA). The length of occlusions was 3-10 cm (mean, 6.3 cm). Lesion characteristics in the three patient groups were similar. Technical success rates were 84% for ELA, 78% for pulsed DLA, and 81% for conventional BA. The 1-year clinical success rate was 69% (22 of 32 patients) in the ELA group, 63% (20 of 32 patients) in the pulsed DLA group, and 66% (21 of 32 patients) in the BA group (differences were not signfficant). Laser-assisted angioplasty

with

multifiber artery

catheters

in

femoropopliteal occlusions did not help improve the technical success rate and 1-year clinical success rate when compared with those of conventional BA. Index Arteries, stenosis luminal

terms: Arteries, extremities, 92.128 laser angioplasty, 92.128 #{149} Arteries, or obstruction, 92.721 #{149} Arteries, transangioplasty, 92.128

Radiology

1992;

184:363-367

From the Departments ogy (P.E.H., S.H.D., C.D.C.),

of Diagnostic Cardiovascular

gery (U.H.), and Medicine

(K.R.K.),

I

RadiolSur-

Eberhard-

Karls-University Tuebingen, Hoppe-Seyler-Str 3, D-7400 Tuebingen, Germany. From the 1991 RSNA scientific assembly. Received December 6, 1991; revision requested January 13, 1992; revision received March 2; accepted March 6. Address reprint requests to P.E.H. 0 RSNA, 1992

of atherosclerotic has been demonstrated the use of pulsed excimer

plaques in vitro laser

BLATION

with

energy (1,2) and pulsed dye laser energy (3,4). However, to be of value in clinical

practice,

energy

delivery

should support primary lion or ablate sufficient occlusive pulsed

material. laser light

artery

recanalization

formed fibers

with single in a ball-tipped

(6). Both

devices

per-

to

guide, created only a small pilot channel, and did not improve the rate of successful primary recanalization.

Multifiber catheters containing circularly arranged quartz fibers can be directed

over

a guide

wire

been

used

artery ment sions,

recanalization (7). of femoropopliteal multifiber catheters

proved

successfully

to reduce

and

have

for coronary

the

In the artery have

grade

treatocclubeen

of steno-

ses; however, efficacy was limited because of the size of the catheters (8). For theoretic considerations, ablation of occlusive material before balloon dilation should be of value for improving the technical success rate of recanalization and the long-term dinical outcome. Updates from clinical vascular laser trials show wide variations in technical and clinical success

rates (9). In this prospective,

randomized

study, we evaluated technical results and clinical follow-up data in patients who underwent pulsed laser-assisted angioplasty of femoropopliteal artery occlusions with multifiber catheters and two different pulsed laser systems. The data were compared with those of patients who underwent

conventional (BA).

balloon

MATERIALS From

March

patients

with

angioplasty

AND 1989

underwent

attempted

laser

(DLA)

in 32. Thirty-two conventional

patients

BA;

tients were considered Patients were excluded lesions

in 32 pa-

angioplasty

indicated

these

pa-

the control group. from the study if additional

surgical

or interventional therapy. The patient population consisted of 66 men and 30 women aged 41-87 years (mean plus or minus standard deviation, 67 years ± 13.6). All patients had chronic ischemic

disease

with

a clinical

history

of

at least 4 months. The symptoms were classified according to recommendations by Rutherford (10). The patients had mild (n = 27), moderate (n = 30), or severe (n = 14) intermittent claudication, isch-

emic rest pain (n = 16), and nonhealing ulcers (n = 9). The study was approved by the Institutional Review Board, and written, informed consent was obtained from each patient. The

mean

cm (range, derwent

length

of occlusions

was

3-40 cm) in patients ELA, 6.3 cm (range,

who 3-10

6.2

uncm) in

patients who underwent DLA, and 6.5 cm (range, 3-9 cm) in patients who underwent conventional BA. Lesions were characterized according to the classification system

recommended

Cardiovascular ogy

(11).

by

and

Grade

2a lesions

25 patients

who

underwent

DLA,

the

Society

of

Interventional were

underwent and

Radiolpresent

ELA,

20 who

in

24 who

underwent

conventional BA. Grade 3a lesions were present in seven patients who underwent ELA, eight who underwent DLA, and 12 who underwent conventional BA. The

Q-switched

xenon

excimer laser ing, Germany) 308

nm

with

chloride

(Max 10; Technolas, emits ultraviolet a pulse

width

pulsed

Gr#{228}felflight of

of 60 nsec

at a

repetition rate of 20 Hz and an energy ency of 20 mJ per pulse. The pulsed-dye laser

(MDL

2000;

Candela,

Wayland,

fluMass)

METHODS

to October

angiographically

was

dye

attempted

iliac

bare fibers (5) and configuration

difficult

(ELA)

and

was

quantities of Application of for femoropopliteal

were

gioplasty

tients

recanaliza-

has been

femoropopliteal artery occlusions 3-10 cm long were recruited for this study. After undergoing diagnostic angiography, each patient was randomly assigned into one of three treatment groups. Excimer laser an-

1990,

proved

96

Abbreviations: DLA = dye laser laser angioplasty.

BA = balloon angioplasty,

angioplasty, ELA = excimer

363

delivers green light of 504 nm width of 1.4 i.sec at a frequency

with a pulse of 10 Hz of 60-80 mJ per

Table

and an energy

Technical

fluency

1 of ELk, DLA, and

Results

ELA

Laser light was transmitted via commercially available 9-F and 7-F multifiber catheters

(Cerampotec,

Bonn,

Germany

No. of patients

for

49), and

=

the

in the distal

7-F catheters

were

part of the popliteal

(n = 15). The 9-F catheters 2O0-m quartz fibers, and

wire,

treatment

required

sheaths

who underwent complete LCP No. of patients with partial luminal opening after LCP Percentage of residual stenosis after LCP

used

artery

Energy

9- or 8-F

femoral artery administered.

into

was performed to occlusions. With

the lesions

pulled

with

When

back,

continuous

passes

attempted

until

no further

widening was obtained. The effect pass was evaluated by injecting

contrast

material

via

the

introducer

sheath

after withdrawal of the laser catheter. The number of pulses applied and the time needed for each passage were recorded. Supplemental BA was performed subsequent to all laser procedures to improve vessel patency. Conventional BA was performed

during

0.035-inch

roadmap

guide

catheters

fluoroscopy

wires

(Terumo)

(Medi-tech/Boston

Watertown,

Mass)

with

with

and

5-F

Scientific, balloon

tenally

5,000 U of heparin was intraaradministered. Flushing was per-

formed

via the introducer

solution

of heparin

and

20 mg of vasodilator Germering, tion. (1,000

Germany)

Intravenous

U/h)

saline per

infusion

was

sheath

tolazoline

continued

longer emboli

with

250,000-1 .5 million hours.

Radiology

20/25

(80)

...

14t

54

17t

...

±

±

46±12

±

1.1

22

...

±

3.8

...

36±15 25 (78) 7

35±15 26(81) 6

2 (40)

2 (29)

2(33)

3 (60)

5 (71)

4(67)

5

who required

of 70%

or more.

The

pro-

a residual stenosis of more than 30% persisted in popliteal arteries. Stent insertion into popliteal arteries was not performed. Clinical investigations included determining the ankle-brachial index 1-3 days be-

fore and 3 days

after

angioplasty

and

after

treatment.

12 months

patients,

the

months

after

other

institutions.

Numbers

data

obtained

In three 6 and

angioplasty

were

12

gathered

giographically or a restenosis

as a complete

at

treated

site. after

Changes

in the

angioplasty

and

dur-

follow-up were classified according to the recommendations by Rutherford (10). Clinical improvement was classified as marked (grade 3), moderate (grade 2), or ing

minimal

(grade

1), as defined

of symptoms

and

with

an analysis

with

and changes No change evaluation

the Student

the

cat-

of the was clasof data t test,

for 24 hours

in

lo-

with for

ELA but tients

in parentheses

2

of variance.

RESULTS Primary recanalization of arterial occlusions with a guide wire was successful in 30 of the 32 patients (94%) in the ELA group, 29 of 32 patients (91%) in the DLA group, and 30 of the 32 patients (94%) in the control group. Complete laser catheter passage was successful in 28 of the

(93%)

who

in only

(86%)

are per-

underwent

25 of the

who

29 pa-

underwent

DLA

(difference was not statistically significant). The mean number of laser catheter passes performed was 3.6 in ELA and The

number

of pulses

ap-

plied per millimeter was lower for DLA, and speed of catheter movement across the occlusion was considerably faster in DLA compared with that in ELA (Table 1). Total occlusions persisted after complete laser passes in four of the 28 patients

obstruction

of more than 50% at the

findings

30 patients

2.8 in DLA.

and 3,6,

If symptoms were indicative of a reocclusion, patients underwent repeat angiography. Reocclusion was defined an-

test,

Technical success of recanalization was defined as vessel patency with a restored

#{149}

diameter

was performed

(Priscoline;

4-36

364

(86)

32±12 27 (84)

100 mL of solu-

LU of urokinase

24/28

stenosis

treatment

ankle-brachial index. sifted as 0. Statistical

a

of heparin

was performed

...

5

of residual

cedure was classified as a technical failure if stent insertion was necessary to sustain sufficient perfusion in femoral arteries or if

egory

containing

than 5 cm. In five patients in the peripheral arteries,

cal thrombolysis

(86)

Note.-GWP = guide-wire passage, LCP = laser catheter passage. centages. * Data are presented as mean plus or minus standard deviation. t was statistically significant (P < .05).

clinical

patients with occlusions shorter than 5 cm and for 48 hours in patients with occlusions with

25/29

advance-

(mm!min)*

surgical

previously

diameters

of 5 or 6 mm and balloon lengths of 2-8 cm. Catheters were introduced via 6-F sheaths. All patients received 100 mg of aspirin per day, starting 2 days before angioplasty and continuing for 6 months. During angioplasty,

catheter

laser

No. of patients

luminal

were

energy

were

(93)

emis-

the catheters

was delivered at the same pulse frequency. The repetition rate was 20 Hz in ELA and 10 Hz in DLA. The speed of catheter advancement was slowed if an increased resistance was noriced. Two, four, or a maximum of six luminal of each

28/30

45

No. of technical successes No. of technical failures No. of patients who required

were

ency of laser catheters was calibrated by means of standard power meters (Technolas; Candela). The laser catheters were gently advanced over the wire and of energy.

30(94)

of pulses!

afterBA*

mark road-map fluoroscopy, a torque-controlled steerable guide wire (Terumo, Tokyo) was manipulated across the lesion. Energy flu-

through

(no.

stent insertion

angiography the borders of the

29 (91)

295±24

of ment

superficial

after local anesthetics

Baseline

sion

)*

Percentage

introducer

the

delivery

Speed

Laser-assisted

to be inserted

30 (94)

GWP

No. of patients

contained 19 the 7-F catheters

respectively.

(n=32)

who underwent

successful

contained 12. These fibers were circularly arranged around a central channel suitable to adopt a 0.035-inch and 0.018-inch guide

BA

DLA (n=32)

(n=32)

ELA; Candela for DLA). The 9-F catheters were used in the femoral artery and the proximal part of the popliteal artery (ii

BA

Conventional

pulse.

(14%)

during

ELA

of the 25 patients (Fig 1). The mean

(20%) grade

stenosis after significantly

laser

the

lower than in DLA (54% Subsequent balloon the

grade

of stenosis

and

in five

during DLA of residual procedure

was

in ELA (45% ± 14) ± 17) (P < .05). dilation reduced to a mean

value

of 32% ± 12 in ELA and 36% ± 15 in DLA (Fig 2). The mean grade of residual stenosis in patients who underwent conventional BA was 35% ± 15, which was not significantly different compared with that in the laser groups. Laser-assisted angioplasty was technically successful in 27 of the

32 patients (84%) in the ELA group and 25 of the 32 patients (78%) in the DLA group compared with 26 of the 32 patients (81%) in the control group (differences were not statistically significant). Stents were inserted (Tantalum Strecker; Medi-tech/Boston SdAugust

1992

I Figure

4 , ,%-

1.

excimer

‘ ,

Angiograrns laser

gioplasty.

demonstrate

assistance

failed

in femoral

a, Angiogram

shows

artery

an-

a 4.5-cm-long

occlusion of the right superficial tery in a 60-year-old man with cation (could walk only 50 m).

femoral arsevere claudib, Despite four

complete passes of a 9-F multifiber laser catheter, the vessel is not patent. c, Angiogram obtained after angioplasty with a 6-mm-diameter balloon shows a low-grade residual stenosis

After

and

0.5 to 0.8,

Scale

and

aspect

of distal

the

dissection.

index

patient

could

rose walk

from 300

m.

is in centimeters.

luminal

opening

after

DLA

(Fig

3) but

in none of those who underwent ELA. Five of the 64 patients (8%) in whom laser-assisted angioplasty was attempted developed groin hemato-

, /.

the

BA, the ankle-brachial

#{149}

mas;

one

of those

dergo surgery. Peripheral patients

patients

emboli

during

had

to un-

occurred

in five

supplemental

BA per-

formed after ELA (n = 3) and DLA (n = 2) and were verified with angiography. All patients with emboli were symptomatic, and three were treated successfully with local thrombolysis. Surgical embolectomy of plaque material was performed in the two patients in whom thrombolysis failed. No complication occurred in any patient in the control group. Short-term clinical outcome was similar for all patient groups. The

.:

grades

of improvement

group were (n = 8), and the patients

3 (n 0 (n who

in the

7), 2 (n

=

ELA

14), 1

=

3) (mean,

=

1.8).

underwent

grades

of improvement lows: 3 (n = 4), 2 (n and 0 (n = 5) (mean,

=

In

DLA,

the

were as fol17), 1 (n = 6), 1.6). The grades

of improvement in patients who underwent conventional BA were 3 (n = 5), 2 (n = 18), 1 (n = 7), and 0 (n = 2) (mean, 1.8). No significant differences were seen between data of the three groups (x2 test; P < .5). None of the patients’ clinical condi-

a

sr:.

C

#{149}

lions

deteriorated.

Clinical Figure 2. Angiograms demonstrate successful excimer laser assistance in femoral artery angioplasty. a, Angiogram shows a 6-cm-long occlusion of the right superficial femoral artery in a 58-year-old man with an ankle-brachial index of 0.6 and moderate claudication (could walk only 100 m). b, Angiogram obtained after four passes with a 9-F multifiber laser catheter shows residual stenosis of 30%-50% . c, Angiogram obtained after supplemental 6-mm BA shows sufficient luminal widening. The pain-free walking distance increased to about 3,000 m, and the ankle-brachial index increased to 0.9.

entific)

and

patients plasty

into the femoral arteries in six in whom laser-assisted angiofailed; this was successful in all cases. Stent insertion was not mdicated in five patients in whom laserassisted angioplasty was unsuccessful

wire passages underwent popliteal bypass surgery.

in the

popliteal

Volume

184

artery. #{149} Number

These 2

patients

seven

results Small

patients

are summarized dissections

were angiographically of 20 patients (40%)

with

failed

guide

femoroTechnical

in Table of the arterial

visible who had

months

improvement in 24 of the

wall

in eight partial

(75%)

ELA

tients

(72%)

of the group.

32 patients (75%) in the control Twelve months after angioclinical improvement was still

in the

in 22 of the

in the

ELA

tients

(63%)

group,

Reocclusions

more

frequently

sions

were

located

DLA

32 pa-

group,

and

32 patients

20 of the

in the

of the 32 patients group (differences cally significant).

1.

23 of the

for 6

in the

plasty, present

group,

lasted 32 patients

DLA

(69%)

32 pa-

group,

(66%) were

24

and

21

in the control not statisti-

(n = 17) occurred in all groups if lein the

distal

Radiology

part

of

365

#{149}

the popliteal artery (n = 6), if lesions were longer than 6 cm (n = 8), and if the runoff was markedly reduced (n = 6). Clinical results are shown in Table 2. DISCUSSION The primary goal of performing laser-assisted angioplasty via multifiber catheters during femoropopliteal artery recanalization was to ablate occlusive material before balloon dilation. Technical efficacy of the laser procedure was limited by failure to pass the guide wire (ELA, 6%; DLA, 9%), failure to completely cross lesions with the laser catheter (ELA, 7%; DLA, 14%), and persistence of obstructions after laser-assisted angioplasty

(ELA,

14%;

DLA,

20%).

The

failure to advance laser catheters through occlusions with the over-thewire approach is most likely related to an insufficient ablation process. Recanalization with multifiber catheters combines ablation at the tip of small quartz fibers and a “Dotter effect” by the catheter. About 50% of the front surface of these catheters is made up of optically inactive cladding between fibers (12). Although DLA was performed by emitting a pulse energy four to five times higher than that used in ELA, the rate of insufficient laser catheter passages could not be decreased. Conversely, DLA caused small dissections of the arterial wall. These dissections may have been generated by laser shock waves and mechanical effects of the nontapered multifiber catheters. Dissections have not been reported for DLA with single bare (13) or balltipped fibers (6) or for ELA with multifiber catheters (5,8). There may be many reasons for persistence of vessel obstructions after laser catheter passages. Incompletely removed thrombus and plaque material tend to recoil into the lumen. Dissections caused by laser angioplasty can promote occlusions. If laser catheter passage has been performed along a primarily dissecting course of the guide wire, the risk of reobstruction is increased. Peripheral emboli occurred in five patients who underwent laserassisted angioplasty. Although emboli were not present on angiograms obtamed immediately after laser catheter passages but after subsequent balloon dilation, the lack of emboli in the patients who underwent conventional BA indicates its relationship to the laser procedure. Loose thrombus and plaque material caused by incomplete laser ablation has an inherent 366

Radiology

#{149}

‘

I, Figure

3.

Angiograms

show

DLA

of the

popliteal

artery.

a, Angiogram

shows

4-cm-long

oc-

clusion of the right popliteal artery in a 77-year-old woman with severe claudication (could walk only 30 m) and an ankle-brachial index of 0.3. b, Angiogram obtained after two passes with a 9-F multifiber laser catheter shows only minimal restoration of vessel lumen. c, After four passages with the laser catheter, the grade of residual stenosis was still greater than 70%, and small dissections were visible (arrows). d, After six passes with the laser catheter, the dissections worsened slightly (arrow), with minimal enlargement of the luminal diameter. e, After dilation with a 5-mm-diameter balloon, the diameter of this vessel segment was sufficient. Thereafter, distal popliteal stenosis was treated with BA with a 4-mm-diameter balloon.

Table 2 Clinical Results

of ELA,

DLA, and Conventional

BA

ELA (n

=

BA

DLA

32)

(n

=

32)

(n

=

32)

Grade of improvement

3 d after angioplasty* 1.8 ± 0.8 1.6 ± 0.7 1.8 ± 0.8 No. of clinical successes at 6 mo 24 (75) 23 (72) 24(75) No. of dlinicalsuccesses at 12 mo 22 (69) 20 (62) 21 (66) No. of reocclusions within 12 mo 5 (21) 6 (30) 6(25) Note.-No differences are significant. Numbers in parentheses are percentages. * Influence of angioplasty on clinical status was assessed by determining the mean categoric changes of all procedures according to the classification recommended by Rutherford (11). Data are presented as mean plus or minus standard deviation. t Determmed for the patients who had clinical improvement after technically successfulELA (n = 24), DLA (n = 20), and BA(n = 24).

risk

of embolization

during

supple-

mental BA. The use of lasers prolonged total treatment time 15-60 minutes. Preparation of the catheter and calibration required only a few minutes, whereas catheter passages required most of the additional time. Laser catheter advancement was about five times faster in DLA than in ELA. Because of the lack of a generally accepted objective monitoring of laser ablation, catheter advancement was controlled subjectively by recording resistance manually. Different speeds of recanalization during ELA and DLA are probably due to different ablation rates, which are dependent on energy fluency (14). The types of occlusions treated with laser-assisted angioplasty and conventional BA were not different, according to the classification of the

Society ventional

of Cardiovascular and InterRadiology (11). Under these

circumstances, the mean grades of residual stenoses after the laser process were equivalent during ELA and

DLA, and additional balloon dilation was indispensable in both groups. The mean grades of finally persisting stenoses in the ELA and DLA groups

were

not

different

from

those

after conventional BA. The rate of technical success was similar in all patient groups (78%-84%), and data are comparable to those for conventional BA reported in the literature (range,

74%-91%)

pulsed

laser

catheters

did

(15-20).

assistance not

help

technical success rate BA in femoropopliteal

Thus,

with

multifiber

improve

the

of conventional artery recanali-

zations.

The acute no difference

clinical outcome showed between laser-assisted August

1992

treatment and conventional BA. Analysis of clinical results according to the classification by Rutherford (10) takes into account symptoms and changes

In arteries of the lower limb, the size of percutaneously applicable multifiber catheters can be matched to luminal dimensions, and laser angio-

11.

of the ankle-brachial of clinical improvement dent of the technique nalization but varied

index. The grade was indepenused for recain relation to the

plasty

the

12.

dilation. The conof this therapeutic unproved, and in-

13.

status

of the

vestigation

of the

arteries

lower

limb. After 12-month follow-up, the rate of continued clinical improvement was similar in patients treated with laser-assisted angioplasty (62%-69%)

and in patients who underwent conventional BA (66%). The 1-year clinical success rates of standard BA reported

for

large

series

ranges

continue.

1.

2.

74%

Our study may be criticized because patients underwent repeat angiography only when symptoms

recurred.

Reocciusions

compensated vessel function

tected.

by

improved may have

Therefore,

sion

rates

and

conventional

been

for

that

our ELA

3.

4.

5.

were collateral gone unde-

1-year

(21%),

DLA

BA (25%)

6.

reocclu(30%),

may

have

underestimated.

The

impetus

the treatment ease is the

tency

will

rather sclerotic

for assessing

of arterial hypothesis

be improved

than displacement plaque. Our

lasers

occlusive that vessel

in

7.

dispa-

by removal results

of atheroindicate

8.

that partial ablation of occlusive material with pulsed laser energy by using presently

not

available

improve

results popliteal

Volume

the

techniques

technical

does

184

Number

#{149}

2

9.

or clinical

of subsequent BA in femoroartery occlusions.

be performed

of these

without

systems

should

U

References

from

to 87% (15,17,18,20-22). These data elucidate that pretreatment of femoropopliteal artery occlusions with pulsed laser energy via multifiber catheters did not improve longterm clinical success.

can

need for balloon ceivable advantage modality remains

10.

Grundfest WS, Litvack F, Forrester J, et al. Laser ablation of human atherosclerotic plaque without adjacent tissue injury. J Am Coil Cardiol 1985; 5:929-933. Litvack F, Grundfest WS, Goldenberg T, et al. Pulsed laser angioplasty: wavelength, power and energy dependencies relevant to clinical application. Lasers Surg Med 1988; 8:60-65. Anderson RR, Jaenke KF, Parrish JA. Mechanism of selective vascular changes caused by dye lasers. Lasers Surg Med 1983; 3:211-215. Prince MR. Deutsch TF, Shapiro AH, et al. Selective ablation of atheromas using a flashlamp-excited dye laser at 465 nm. Proc Natl Acad Sci USA 1986; 83:7064-7068. Litvack F, Grundfest WS, Adler L, et al. Percutaneous excimer-laser and excimerlaser-assisted angioplasty of the lower extremities: results of initial clinical trial. Radiology 1989; 172:331-335. Murray A, Mitchell DC, Grasty M, Wood RFM, Edwards DH, Basu R. Peripheral laser angioplasty with pulsed dye laser and bail-tipped optical fibers. Lancet 1989; 2:1471-1474. Karsch KR, Haase KK, Voelker W, Baumbach A, Mauser M, Seipel L. Percutaneous coronary excimer laser angioplasty in patients with stable and unstable angina pectoris. Circulation 1990; 81:1849-1859. Huppert PE, Duda SH, Seboldt H, Karsch KR, Claussen CD. Periphere excimer-laserangioplastie: indikationen, methode und klinische ergebnisse. Dtsch Med Wochenschr 1991; 116:161-167. Bonn J. Clinical utility of laser recanalization in occluded peripheral arteries. Radiology 1991; 178:323-325. Rutherford RB. Standards for evaluating results of interventional therapy for peripheral vascular disease. Circulation 1991; 83(suppl 1):6-11.

14.

15.

Standards of Practice Committee of the Society of Cardiovascular and Interventional Radiology. Guidelines for percutaneous transluminal angioplasty. JVIR 1990; 1:5-15. Duda SH, Karsch KR, Haase KK, Huppert PE, Claussen CD. Laser ring catheters in excimer laser angioplasty. Radiology 1990; 175:269-270. Leon MB, Almagor Y, Bartorelli AL, et at. Fluorescence-guided laser-assisted balloon angioplasty in patients with femoropopliteal occlusions. Circulation 1990; 81:143155. Duda SH, Huppert PE, Arndt V, et at. In vitro and clinical feasibility study with an over-the-wire delivery system for pulsed dye laser angioplasty. JVIR 1992; 3:59-65. Martin EC, Fankuchen El, Karlson KB, et at. Angioplasty for femoral artery occlusion: comparison with surgery. AJR 1981; 137:915-919.

16.

17.

18.

19.

20.

21.

22.

Lu CT, Zarins CK, Yang CF. Sottiurai V. Long-segment arterial occlusion: percutaneous transluminal angioplasty. AJR 1982; 138:119-122. Murray RRJr, Hewes RC, White RI, et at. Long-segment femoropopliteal stenoses: is angioplasty a boon or a bust? Radiology 1987; 162:473-476. Krepel VM, van Andel HJ, van Erp WFM, Breslau BJ. Percutaneous transluminal angioplasty of the femoropoptiteal artery: initial and long-term results. Radiology 1985; 165:325-328. Morgenstern BR, Getrajdman GI, Laffey KJ, Bixon R, Martin EC. Total occlusions of the femoropopliteal artery: high technical success rate of conventional balloon angioplasty. Radiology 1989; 172:937-940. Hewes RC, White RI, Murray RR, et at. Long-term results of superficial femoral artery angioplasty. AJR 1986; 146:10251029. Johnston W, Rae M, Hogg-Johnston SA, et at. 5-year results of a prospective study of percutaneous transluminal angioplasty. Ann Surg 1987; 206:403-413. Zeitler E. Percutaneous dilatation and recanatization of iliac and femoral arteries. Cardiovasc Intervent Radiol 1980; 3:207212.

Radiology

367

#{149}