ANGIOLOGY The Journal
of Yascular Diseases
in Endovascular Surgery: Recent Technical Advances to Enhance Intervention Selection and Failure Analysis
Angioscopy
Edward B. Diethrich, M.D., F.A.C.A., F.I.C.A. Boris Yoffe, M.D. J.J. Kiessling, M.D. Osvaldo Santiago, M.D. Ilhan Bahadir, M.D. Larry A. Stern, M.D. and Daniel Lavine, M.D.* PHOENIX, ARIZONA
Abstract Recent technical and procedural modifications have greatly enhanced the usefulness of angioscopy during angioplasty. A pulsed irrigation system, proximal and distal blood flow control by pressure, and attention to sheath/vessel diameter ratio were incorporated into a study in which angioscopy was used for pretreatment assessment in 23 patients with symptomatic peripheral vascular disease presenting for initial (8 patients) evaluation or repeat treatment (15 patients) following a previous vascular procedure. Twenty-five lesions were examined with a 2.3 mm flexible angioscope equipped with an irrigating lumen; there were no
complications attributable to angioscopy. The angioscope was useful in the characterization of lesions for selection of the recanalization technique. Lesions more amenable to initial atherectomy were visualized in 12 patients; 7 occlusions were successfully treated with laser/balloon angioplasty, with angioscopy assisting in probe and/or wire passage in 4 cases. Three late reocclusions were identified angioscopically as due solely to thrombosis, indicating the need for thrombolytic therapy. Angioscopy also identified 4 cases of incomplete recanalization despite a satisfactory arteriographic image. Angioscopy was also used to evaluate stenotic lesions unaccompanied by thrombus formation in patients previously treated with laser-assisted angioplasty. Histologic evaluation of the biopsied plaques identified intimal hyperplasia as the etiology, matching identically similar specimens harvested from a lesion treated with balloon dilation only. From the Department of Cardiovascular Surgery, Arizona Heart Institute, the Cardiovascular Center Hospital-Phoenix, and the *Department of Pathology, Humana Hospital-Phoenix, Phoenix, Arizona. Presented at the International
of Excellence at Humana
Congress III: Lasers, Stents and Interventions in Vascular Disease, Scottsdale, Arizona, February, 1990.
1
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2 Introduction The treatment of vascular occlusive disease has undergone a revolution in just a few short years. Endovascular techniques for recanalization have proliferated in a frenzied atmosphere of excitement shared by cardiologists, radiologists, and many vascular surgeons. Paralleling this development in therapeutic technology has been the pursuit of devices to keep pace with the demands for enhanced intraluminal diagnosis and monitoring.
With recent advances in endoscopy, fiberoptic technology, and miniaturization, interventionists and vascular surgeons have a fascinating new array of angioscopes that embody and effectively meed today’s trends toward direct visualization and percutaneous
application. As a technique, angioscopy is certainly not new, having been proposed and experimented with for more than sixty-five years. 1-2 The technological explosion that began in the late 1970S3-9 with the birth of usable vascular endoscopes has brought forth angioscopes sufficiently small and flexible to perform adequately in small-caliber catheters suitable for percutaneous insertion. Coupled with lower costs and disposable devices, the routine use of angioscopes is now practical. 10-15 In spite of these device improvements, however, maintaining a blood-free field of observation has continued to plague many investigators. A recently developed volume/pressure-controlled infusion pump was used in this study to provide optimum evacuation of blood with the lowest irrigant volume. Moreover, three additional maneuvers were incorporated into the technique to further reduce blood flow into the field. First, whenever practical, the percutaneous introducer sheath was sized as closely as possible to the caliber of the superficial femoral artery, thereby reducing flow around the sheath. Second, a blood pressure cuff was placed blow the knee and inflated whenever an observation was made, to lessen retrograde collateral flow. Lastly, manual compression was applied at the level of the common femoral or external iliac artery at the inguinal ligament to block inflow. The combination of these three procedures with the pulsed irrigating solution provided consistently favorable angioscopic images. Utilizing these improved imaging techniques, a study was designed to evaluate angioscofor its usefulness in the selection of appropriate vascular interventions based on visualipy zation of the specific lesion pathology. Additionally, the angioscope was used to correlate direct observations with histologic study of restenotic lesions secondary to laser-assisted angioplasty in patients undergoing retreatment. Materials and Methods
Twenty-three patients (15 men, 8 women) with an average age of sixty-seven years (range fifty-one to eighty) were evaluated for symptoms of disabling claudication (18, 780/o) or rest pain (5 , 22 070 ) . Eleven patients (48 ~70 ) had concomitant coronary artery disease, 7 (30Vo) were hypertensive, and 8 (35070) had diabetes mellitus. Fifteen patients were presenting for failure of previous vascular procedures in the lower limbs (balloon angioplasty : 4; laser-assisted angioplasty: 9; atherectomy: 1; and bypass surgery: 1). Both percutaneous and intraoperative angioscopy were performed using 2.3 or 3.0 mm
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
3
FIG. 1. The 2.3
(right) and 3.0 (left) disposable angioscopes for percutaneous and intraoperative intraluminal viewing. mm
disposable angioscopes (Figure 1). A medical video color monitor with hardcopy documentation available through a videorecorder was used for angioscopic display. An angioscopy irrigation system (Figure 2) provided computer-assisted, pulsed irrigation and image storage to maximize visibility with minimal flush volume. Heparinized (1 unit/mL) saline was delivered under 300 mmHg pressure at preset pulse durations (range: 0.5 to 20 seconds) on demand via a foot pedal. Notably, this infusion system was able to limit the saline bolus to a volume sufficient to clear the vessel a distance equal to the scope’s focal length to avoid fluid overload. (Generally, no more than 500 mL of irrigant were infused during the entire observation period.) Further, synchronization of the flushing with image capture for the digitized output allowed both freeze-frame and real-time imaging. For percutaneous access, the common femoral artery was punctured with an 18 gauge Potts-Cournard needle for insertion of a 0.035-inch guidewire followed by a 9 Fr introducer and appropriately sized sheath. Contrast injection confirmed adequate sheath placement prior to angioscopy. To assist in obtaining a clear field of observation, blood flow was inhibited as much as possible. Vascular clamps controlled proximal flow during intraoperative angioscopy. In percutaneous cases, the sheath was sized as nearly as possible to the artery’s diameter to provide adequate proximal control, but manual compression of the common femoral or external iliac artery was sometimes necessary (Figure 3). Retrograde flow in either case was reduced by a pressure cuff placed below the knee and inflated during periods of observation.
patients with failed previous interventions underwent endovascular biopsy of their recurrent lesions using a directional atherectomy catheter for correlation of the visual image with histologic identification of the restenosis. Lesions treated with laser energy were compared with plaque samples from balloon-dilated vessels. In these patients, the stenotic lesion was identified by the angioscope. The atherectomy catheter was then passed down the sheath and, under fluoroscopic control, positioned at the lesion. With the stabilizing balloon inflated, three passes of the cutting mechanism Five
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
4
FIG. 2. The
angiocopy irrigation
system delivers pressured, volumecontrolled pulses of heparinized saline to clear the field of observation
during angioscopy.
made. Three additional samplings were taken from the same lesion by deflating the balloon and rotating the atherectomy catheter 90 ° until four samples around the circumference of the lesion had been collected. The specimens were fixed in formalin and sent for histologic examination. The tissues were processed, sectioned, and stained with hematoxylin and eosin for examination by the pathologist.
were
Results A total of 25 vessels in the 23 patients were examined for evaluation of existing disease and treatment selection. Fourteen patients in this group were being evaluated for return of symptoms following previous vascular interventions; half of these patients had undergone bilateral treatments, but only 1 presented with recurrent symptoms in both limbs. One additional retreatment patient presented with a polytetrafluoroethylene (PTFE) graft that had occluded. The remaining 8 patients (1 with bilateral lesions) were undergo-
ing initial
treatment.
In the primary treatment group,
angioscopy was useful in the selection of the appropriwith bilateral lesions) were treated with laser-assisted patients (1 angioplasty, the angioscope being used to visualize diffuse lesions appropriate for that modality. In 3 patients, the angioscopic image identified concentric lesions amenable to Transluminal Endarterectomy Catheter (TEC) atherectomy.
ate intervention. Three
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
5
FIG. 3. Clear
viewing fields for
be maintained by angioscopy combining the pulsed infusion system with pressure control of proximal and distal collateral blood flow. For percutaneous angioscopy, a sheath (B), sized to approximate the vessel’s diameter, controls inflow with the help of manual compression (A) on the common femoral or external iliac artery. A below-knee pressure cuff (C) is inflated during observation periods to inhibit retrograde flow. can
In another 2
patients, thrombosis was discovered in the popliteal arteries. Following thrombolysis was a bolus dose (250,000 units) of urokinase, the angioscope was reintroduced. In 1, the stenotic lesion was lying at the branching of the posterior tibial artery and, in the other, in the popliteal artery itself. After balloon dilation, heparin (500 units/hr) and urokinase (90,000 units/hr) were infused through separate catheters at the clot site until all thrombi were completely lysed, as assessed via the angioscope. In 1 of these patients undergoing a primary laser-assisted angioplasty, the completion angioscopic image detected a perforation of the superficial femoral artery (SFA) in the adductor canal caused by the unguided hybrid probe. With the help of the angioscope, a wire was passed beyond the area of perforation to enlarge the remaining SFA and popliteal lesions via balloon. Among the 15 patients with previous vascular therapy, the angioscope assisted in the selection of appropriate treatment: 3 occlusions were treated with thrombolysis alone when the angioscope detected no significant restenosis. One occluded vessel was dilated only; another 2 patients with a total of 3 lesions were atherectomized prior to balloon dilation. Five patients were treated with atherectomy alone; 1 other was recanalized with atherectomy and laser-assisted angioplasty. The 1 PTFE graft occlusion was opened with the combined laser/balloon treatment. Only 2 patients were released. The directional atherectomy catheter was used following angioscopy to obtain biopsies of the recurrent lesions in 4 patients who had been treated initially with laser-assisted angioplasty. Tissue was also excised for histologic comparison from 1 patient with an iliac artery lesion that had balloon angioplasty only prior to endovascular stenting. Patholog-
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6 ic evaluation of the restenotic materials from the laser-treated patients identified intimal hyperplasia as the primary cause of restenosis in all biopsy specimens. This matched histologically with the restenotic material taken from the balloon-treated artery (Figure 4). No complications related to the use of the angioscope were encountered in this group of patients, and the device performed satisfactorily, particularly with the technical modifications introduced into the angioscopy program.
Discussion
Today’s proliferation of intraluminally applied recanalization techniques has supplied increasing justification for quick, simple, reproducible angioscopic documentation of their results and/or complications. Moreover, the complementary advantages of threedimensional angioscopy to planar arteriography have become well known, particularly in the identification of thrombus, ulceration, dissection, flaps, and hemorrhage.l4 However, another aspect of angioscopic visualization needs to be explored: the expansion of its diagnostic capabilities to pretreatment use for intervention selection. This obvious boon to more precise disease treatment has been available to vascular surgeons for some time, though it has been relatively ignored.&dquo; Because the first smalldiameter angioscopes were evaluated intraoperatively, surgeons took advantage of this bird’s-eye view to check anastomotic sites for suture abnormalities or intimal flaps, 14’11 to assess venous valvotomies on in situ bypass veins,I7,18 to verify the satisfactory performance of endarterectomies,’9 and to monitor thromboembolectomy for more efficacious balloon placement and enhanced removal of adherent thrombus.2o,21 They did not immediately perceive the angioscope’s potential as a preoperative therapeutic tool. Once angioscopes had been sufficiently miniaturized, percutaneous application became feasible .22,2’ Although some investigators have attested to the viability of this percutaneous diagnostic technique in both the peripheral and coronary arteries,22-25 the novelty of this exciting on-the-spot viewing and the interventionist’s somewhat obstinate preference for standard arteriographic imaging have hindered the definition of indications for its use by the very physicians who would benefit most. We began using angioscopy as a curiosity during vascular surgery for evaluation of laser-assisted angioplasty. We soon found, however, that it provided such a superior definition of therapeutic results over contrast imaging that we incorporated it as part of our routine evaluation procedures in peripheral angioplasty and atherectomy. It then occurred to us that we were overlooking several obvious advantages of the device. One was preoperative assessment for the identification of lesion pathology more accurate than that available from the preoperative arteriogram. In the series of patients we report here, the angioscope allowed us to determine that thrombosis alone and not atherosclerotic plaque was responsible for late reocclusion in former angioplasty patients, saving these patients the usually requisite balloon dilation following thrombolysis. Another important aspect to this lesion identification was the ability to determine whether or not stenotic lesions would be amenable to laser ablation, balloon dilation, or atherectomy. Eccentric stenotic lesions are not usually applicable to laser ablation be-
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7
FtG. 4. Biopsy specimens harvested by atherectomy from (A) a balloon-dilated artery and (B) an artery treated with laser-assisted angioplasty. The specimens show identical intimal hyperplasia.
probe follows the contour of the plaque, doing little to debulk the lesion. In these cases, atherectomy or dilation is more efficacious. Similarly, less significant stenotic plaques identified angioscopically following preliminary thrombolysis for occlusion may be sufficiently treated by dilation alone. As an assessment tool following an intervention (laser or atherectomy), angioscopy showed residual plaque that looked nearly untouched by the intervention despite the arteriographic appearance of a satisfactory luminal channel. From this, we could then select further methods that would sufficiently recanalize the artery to our visual satisfaction. We also found the angioscope particularly helpful as a guidance tool. In the larger arteries, both the angioscope and the laser probe or wire could be inserted simultaneously. The angioscope let us see the central channel of even the tightest stenoses for proper passage of the probe. We found the visual assistance for wire guidance valuable when approaching collaterals to keep the wire in the selected lumen. cause
the
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8 In cases of perforation, as was seen in 1 patient from this series, the angioscope assisted in the safe guidance of a wire past the intimal injury on which the wire might have snagged. In this way, further distal treatment could be accomplished without having to abandon the entire recanalization effort, as had been necessary in the past. Of course, all this intraprocedural monitoring assistance was accomplished without increasing the radiation dosage to the patient and staff. Another important use of the angioscope in this series of patients was to assist in the evaluation of restenosis. Because there exists some question of whether the etiology of restenosis after balloon dilation differs from that responsible for restenosis following laser angioplasty, we used the angioscope in a small cohort of patients to identify restenotic lesions without attendant thrombus that could be biopsied for histologic examination. The directional atherectomy catheter is the only recanalization device that cuts away and captures atherosclerotic material, making it ideal for biopsies.26 From several samplings of laser-treated vessels, we found the restenosis to arise from intimal hyperplasia identical to that seen in a lesion treated by balloon dilation only. While it is true that the laser-treated lesions had been dilated subsequent to laser ablation, there was no change in the mechanism of restenosis. It is feasible then to suppose that any injury to the lumen from the tandem treatments was solely related to the balloon, at least in these instances. Of course, it is equally likely that laser treatment induces the same type of intimal hyperplasia. Further evaluation on this point will require specimen samples from restenotic lesions that underwent sole laser therapy, a relatively uncommon occurrence.
Complications with the angioscope have been reported as arterial damage (plaque disruption, perforation), spasm, thrombosis/embolism, and fluid overload&dquo;; however, we encountered no complications attributable to the angioscopic technique. Notably, there was no instance of spasm even as the smaller arteries were approached. Percutaneous angioscopy, which we use whenever feasible, offers several benefits in addition to its diagnostic advantages. First, it does not require the use of contrast material. This makes it quite valuable for diagnosis in patients with demonstrated or suspected allergy to dye. No radiation is involved, an obvious advantage in itself as noted above. The percutaneous access makes it simple to insert without the need for arterial cutdown. Used routinely, we found angioscopy in either mode added no more than ten to fifteen minutes to any procedure. Technically, clear fields are simpler to maintain in the limb arteries with the pulsed infusion pump and suppression of antegrade and retrograde blood flow. Usually the sheath is a sufficient impediment to inflow for percutaneous procedures, but on occasion, the femoral artery must be manually compressed. Retrograde flow is controllable with inflation of the below-knee pressure cuff during observation periods. Moreover, irrigant volume during viewing was markedly reduced with the system’s synchronized pulse administration feature. However, the inability to maintain a clear field in the large-diameter iliac arteries during retrograde passage without contralaterally applied balloon occlusion still precludes the angioscope’s usefulness in this area on a routine basis.
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9
Steerability of the angioscope, which has been a problem in the past, particularly with the longer catheters, is still not perfect. Wire guidance is of use to maintain the optical tip in coaxial alignment for angioscopes equipped with a suitable channel, but we have found that torqueing and retracting the catheter are usually sufficient to reestablish the central position of the flexible percutaneous models. Conclusion
Despite the few technical problems that remain to be solved, we are convinced that angioscopy is a valuable complement to arteriography in both its diagnostic and therapeutic modes, and we recommend its routine inclusion in any intervention program. Edward B. Diethrich, M.D., F.A. C.A., F.I.C.A. Arizona Heart Institute PO Box 10, 000 Phoenix, AZ 85064
References 1. Cutler EC, Levine A, Beck CS: The surgical treatment of mitral stenosis: Experimental and clinical studies. Arch Surg 9:689-821, 1924. 2. Greenstone SM, Shore JM, Heringman EC, et al: Arterial endoscopy (arterioscopy). Arch Surg 93:811-812, 1966. 3. Crispin HA, Van Baarle AF: Intravascular observation and surgery using the flexible fiberscope. Lancet 1:750-751, 1973. 4. Vollmar JF, Storz LW: Vascular endoscopy: Possibilities and limits of its clinical application. Surg Clin North Am 54:111-122, 1974. 5. Towne JB, Berhard VM: Vascular endoscopy: Useful tool or interesting toy. Surgery 82:415-419, 1977. 6. Tanabe T, Yokota A, Sugie S: Cardiovascular endoscopy : Development and clinical application. Surgery 87:375-379, 1980. 7. Moser KM, Shure D, Harrell JH, et al: Angioscopic visualization of pulmonary emboli. Chest 77:198-201, 1980. 8. Spears JR, Marais HJ, Serur J, et al: In vivo coronary angioscopy. J Am Coll Cardiol 1:1311-1314, 1983. 9. Lee G, Ikeda RM, Stobbe D, et al: Laser irradiation of human atherosclerotic obstructive disease: Simultaneous visualization and vaporization achieved by a dual fiberoptic catheter. Am Heart J 105:163-164, 1983. 10. Seeger JM, Abela GS: Angioscopy as an adjunct to arterial reconstructive surgery. A preliminary report. J Vasc Surg 4:315-320, 1986. 11. Abela GS, Seeger JM, Barbieri E, et al: Laser angioplasty with angioscopic guidance in humans. J Am Coll Cardiol 8:184-192, 1986.
12. White GH, White RA, Kopchok GE, et al: Intraoperative video angioscopy compared with arteriography during peripheral vascular operations. J Vasc Surg 6:488-495, 1987. 13. White GH: Angioscopy and lasers in cardiovascular surgery: Current applications and future prospects. Aust NZ J Surg 58:271-274, 1988. 14. Grundfest WS, Litvak F, Glick D, et al: Intraoperative decisions based on angioscopy in peripheral vascular surgery. Circulation 78(suppl I):I-13-1-17, 1988. 15. White GH, White RA, eds: Angioscopy: Vascular and Coronary Applications. Chicago: Year Book, 1989. 16. Crew J: Angioscopy for in situ bypass grafting. In: Angioscopy: Vascular and Coronary Applications, ed. by Chicago: Year Book, 1980, pp 65-71. 17. Mehigan JT: Angioscopic preparation of the in situ saphenous vein or arterial bypass: Technical considerations. In: Angioscopy: Vascular amd Coronary Applications, ed. by White GH, White RA, Chicago: Year Book 1989, pp 72-75. 18. Chin AK, Fogarty TJ: Specialized techniques of angioscopic valvulotomy for in situ vein bypass. In: Angioscopy : Vascular and Coronary Applications ed. by White GH, White RA. Chicago: Year Book, 1989, pp 76-83. 19. Mehigan JT: Carotid angioscopy. In: Angioscopy: Vascular and Coronary Applications, ed. by White GH, White RA. Chicago: Year Book, 1989, pp 84-88. 20. White GH: Angioscopic thromboembolectomy. In: Angioscopy: Vascular and Coronary Applications, ed. by White GH, White RA. Chicago: Year Book, 1989, pp 123-138.
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10 Kopchok GE, et al: Angioscopic thromboembolectomy: Preliminary obser-
21. White GH, White RA,
vations with a recent technique. J Vasc Surg 7:318-325, 1988. 22. Beck A: Percutaneous angioscopy. First reports on percutaneous transluminal angioplasty and local lysis under angioscopic conditions. Radiology 27:555-559. 1987. 23. Beck A, Reinbold WD, Blum U, et al: Clinical application of percutaneous transluminal angioscopy. Herz 13:392-399, 1988. 24. Ramee SR, White CJ: Percutaneous coronary angioscopy. In: Angioscopy: Vascular and Coronary Applications, ed. by White GH, White RA. Chicago : Year Book, 1989, pp 161-169.
25. Uchida Y, Hasegawa K, Kawamura K, et al: Angioscopic observation of the coronary luminal changes induced by percuraneous transluminal coronary angioplasty. Am Heart J 117:769-776, 1989. 26. Dorros G, Lewin RF, Sachdev N, et al: Percutaneous atherectomy of occlusive peripheral vascular disease : Stenoses and/or occlusions. Cathet Cardiovasc Diag 18:1-6, 1989. 27. Wilson SE: Angioscopy: indications, applications, and complications. In: Angioscopy: Vascular and Coronary Applications, ed. by White GH, White RA. Chicago: Year Book, 1989, pp 37-44.
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
of Yascular Diseases
in Endovascular Surgery: Recent Technical Advances to Enhance Intervention Selection and Failure Analysis
Angioscopy
Edward B. Diethrich, M.D., F.A.C.A., F.I.C.A. Boris Yoffe, M.D. J.J. Kiessling, M.D. Osvaldo Santiago, M.D. Ilhan Bahadir, M.D. Larry A. Stern, M.D. and Daniel Lavine, M.D.* PHOENIX, ARIZONA
Abstract Recent technical and procedural modifications have greatly enhanced the usefulness of angioscopy during angioplasty. A pulsed irrigation system, proximal and distal blood flow control by pressure, and attention to sheath/vessel diameter ratio were incorporated into a study in which angioscopy was used for pretreatment assessment in 23 patients with symptomatic peripheral vascular disease presenting for initial (8 patients) evaluation or repeat treatment (15 patients) following a previous vascular procedure. Twenty-five lesions were examined with a 2.3 mm flexible angioscope equipped with an irrigating lumen; there were no
complications attributable to angioscopy. The angioscope was useful in the characterization of lesions for selection of the recanalization technique. Lesions more amenable to initial atherectomy were visualized in 12 patients; 7 occlusions were successfully treated with laser/balloon angioplasty, with angioscopy assisting in probe and/or wire passage in 4 cases. Three late reocclusions were identified angioscopically as due solely to thrombosis, indicating the need for thrombolytic therapy. Angioscopy also identified 4 cases of incomplete recanalization despite a satisfactory arteriographic image. Angioscopy was also used to evaluate stenotic lesions unaccompanied by thrombus formation in patients previously treated with laser-assisted angioplasty. Histologic evaluation of the biopsied plaques identified intimal hyperplasia as the etiology, matching identically similar specimens harvested from a lesion treated with balloon dilation only. From the Department of Cardiovascular Surgery, Arizona Heart Institute, the Cardiovascular Center Hospital-Phoenix, and the *Department of Pathology, Humana Hospital-Phoenix, Phoenix, Arizona. Presented at the International
of Excellence at Humana
Congress III: Lasers, Stents and Interventions in Vascular Disease, Scottsdale, Arizona, February, 1990.
1
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
2 Introduction The treatment of vascular occlusive disease has undergone a revolution in just a few short years. Endovascular techniques for recanalization have proliferated in a frenzied atmosphere of excitement shared by cardiologists, radiologists, and many vascular surgeons. Paralleling this development in therapeutic technology has been the pursuit of devices to keep pace with the demands for enhanced intraluminal diagnosis and monitoring.
With recent advances in endoscopy, fiberoptic technology, and miniaturization, interventionists and vascular surgeons have a fascinating new array of angioscopes that embody and effectively meed today’s trends toward direct visualization and percutaneous
application. As a technique, angioscopy is certainly not new, having been proposed and experimented with for more than sixty-five years. 1-2 The technological explosion that began in the late 1970S3-9 with the birth of usable vascular endoscopes has brought forth angioscopes sufficiently small and flexible to perform adequately in small-caliber catheters suitable for percutaneous insertion. Coupled with lower costs and disposable devices, the routine use of angioscopes is now practical. 10-15 In spite of these device improvements, however, maintaining a blood-free field of observation has continued to plague many investigators. A recently developed volume/pressure-controlled infusion pump was used in this study to provide optimum evacuation of blood with the lowest irrigant volume. Moreover, three additional maneuvers were incorporated into the technique to further reduce blood flow into the field. First, whenever practical, the percutaneous introducer sheath was sized as closely as possible to the caliber of the superficial femoral artery, thereby reducing flow around the sheath. Second, a blood pressure cuff was placed blow the knee and inflated whenever an observation was made, to lessen retrograde collateral flow. Lastly, manual compression was applied at the level of the common femoral or external iliac artery at the inguinal ligament to block inflow. The combination of these three procedures with the pulsed irrigating solution provided consistently favorable angioscopic images. Utilizing these improved imaging techniques, a study was designed to evaluate angioscofor its usefulness in the selection of appropriate vascular interventions based on visualipy zation of the specific lesion pathology. Additionally, the angioscope was used to correlate direct observations with histologic study of restenotic lesions secondary to laser-assisted angioplasty in patients undergoing retreatment. Materials and Methods
Twenty-three patients (15 men, 8 women) with an average age of sixty-seven years (range fifty-one to eighty) were evaluated for symptoms of disabling claudication (18, 780/o) or rest pain (5 , 22 070 ) . Eleven patients (48 ~70 ) had concomitant coronary artery disease, 7 (30Vo) were hypertensive, and 8 (35070) had diabetes mellitus. Fifteen patients were presenting for failure of previous vascular procedures in the lower limbs (balloon angioplasty : 4; laser-assisted angioplasty: 9; atherectomy: 1; and bypass surgery: 1). Both percutaneous and intraoperative angioscopy were performed using 2.3 or 3.0 mm
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
3
FIG. 1. The 2.3
(right) and 3.0 (left) disposable angioscopes for percutaneous and intraoperative intraluminal viewing. mm
disposable angioscopes (Figure 1). A medical video color monitor with hardcopy documentation available through a videorecorder was used for angioscopic display. An angioscopy irrigation system (Figure 2) provided computer-assisted, pulsed irrigation and image storage to maximize visibility with minimal flush volume. Heparinized (1 unit/mL) saline was delivered under 300 mmHg pressure at preset pulse durations (range: 0.5 to 20 seconds) on demand via a foot pedal. Notably, this infusion system was able to limit the saline bolus to a volume sufficient to clear the vessel a distance equal to the scope’s focal length to avoid fluid overload. (Generally, no more than 500 mL of irrigant were infused during the entire observation period.) Further, synchronization of the flushing with image capture for the digitized output allowed both freeze-frame and real-time imaging. For percutaneous access, the common femoral artery was punctured with an 18 gauge Potts-Cournard needle for insertion of a 0.035-inch guidewire followed by a 9 Fr introducer and appropriately sized sheath. Contrast injection confirmed adequate sheath placement prior to angioscopy. To assist in obtaining a clear field of observation, blood flow was inhibited as much as possible. Vascular clamps controlled proximal flow during intraoperative angioscopy. In percutaneous cases, the sheath was sized as nearly as possible to the artery’s diameter to provide adequate proximal control, but manual compression of the common femoral or external iliac artery was sometimes necessary (Figure 3). Retrograde flow in either case was reduced by a pressure cuff placed below the knee and inflated during periods of observation.
patients with failed previous interventions underwent endovascular biopsy of their recurrent lesions using a directional atherectomy catheter for correlation of the visual image with histologic identification of the restenosis. Lesions treated with laser energy were compared with plaque samples from balloon-dilated vessels. In these patients, the stenotic lesion was identified by the angioscope. The atherectomy catheter was then passed down the sheath and, under fluoroscopic control, positioned at the lesion. With the stabilizing balloon inflated, three passes of the cutting mechanism Five
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
4
FIG. 2. The
angiocopy irrigation
system delivers pressured, volumecontrolled pulses of heparinized saline to clear the field of observation
during angioscopy.
made. Three additional samplings were taken from the same lesion by deflating the balloon and rotating the atherectomy catheter 90 ° until four samples around the circumference of the lesion had been collected. The specimens were fixed in formalin and sent for histologic examination. The tissues were processed, sectioned, and stained with hematoxylin and eosin for examination by the pathologist.
were
Results A total of 25 vessels in the 23 patients were examined for evaluation of existing disease and treatment selection. Fourteen patients in this group were being evaluated for return of symptoms following previous vascular interventions; half of these patients had undergone bilateral treatments, but only 1 presented with recurrent symptoms in both limbs. One additional retreatment patient presented with a polytetrafluoroethylene (PTFE) graft that had occluded. The remaining 8 patients (1 with bilateral lesions) were undergo-
ing initial
treatment.
In the primary treatment group,
angioscopy was useful in the selection of the appropriwith bilateral lesions) were treated with laser-assisted patients (1 angioplasty, the angioscope being used to visualize diffuse lesions appropriate for that modality. In 3 patients, the angioscopic image identified concentric lesions amenable to Transluminal Endarterectomy Catheter (TEC) atherectomy.
ate intervention. Three
Downloaded from ang.sagepub.com at Freie Universitaet Berlin on May 14, 2015
5
FIG. 3. Clear
viewing fields for
be maintained by angioscopy combining the pulsed infusion system with pressure control of proximal and distal collateral blood flow. For percutaneous angioscopy, a sheath (B), sized to approximate the vessel’s diameter, controls inflow with the help of manual compression (A) on the common femoral or external iliac artery. A below-knee pressure cuff (C) is inflated during observation periods to inhibit retrograde flow. can
In another 2
patients, thrombosis was discovered in the popliteal arteries. Following thrombolysis was a bolus dose (250,000 units) of urokinase, the angioscope was reintroduced. In 1, the stenotic lesion was lying at the branching of the posterior tibial artery and, in the other, in the popliteal artery itself. After balloon dilation, heparin (500 units/hr) and urokinase (90,000 units/hr) were infused through separate catheters at the clot site until all thrombi were completely lysed, as assessed via the angioscope. In 1 of these patients undergoing a primary laser-assisted angioplasty, the completion angioscopic image detected a perforation of the superficial femoral artery (SFA) in the adductor canal caused by the unguided hybrid probe. With the help of the angioscope, a wire was passed beyond the area of perforation to enlarge the remaining SFA and popliteal lesions via balloon. Among the 15 patients with previous vascular therapy, the angioscope assisted in the selection of appropriate treatment: 3 occlusions were treated with thrombolysis alone when the angioscope detected no significant restenosis. One occluded vessel was dilated only; another 2 patients with a total of 3 lesions were atherectomized prior to balloon dilation. Five patients were treated with atherectomy alone; 1 other was recanalized with atherectomy and laser-assisted angioplasty. The 1 PTFE graft occlusion was opened with the combined laser/balloon treatment. Only 2 patients were released. The directional atherectomy catheter was used following angioscopy to obtain biopsies of the recurrent lesions in 4 patients who had been treated initially with laser-assisted angioplasty. Tissue was also excised for histologic comparison from 1 patient with an iliac artery lesion that had balloon angioplasty only prior to endovascular stenting. Patholog-
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6 ic evaluation of the restenotic materials from the laser-treated patients identified intimal hyperplasia as the primary cause of restenosis in all biopsy specimens. This matched histologically with the restenotic material taken from the balloon-treated artery (Figure 4). No complications related to the use of the angioscope were encountered in this group of patients, and the device performed satisfactorily, particularly with the technical modifications introduced into the angioscopy program.
Discussion
Today’s proliferation of intraluminally applied recanalization techniques has supplied increasing justification for quick, simple, reproducible angioscopic documentation of their results and/or complications. Moreover, the complementary advantages of threedimensional angioscopy to planar arteriography have become well known, particularly in the identification of thrombus, ulceration, dissection, flaps, and hemorrhage.l4 However, another aspect of angioscopic visualization needs to be explored: the expansion of its diagnostic capabilities to pretreatment use for intervention selection. This obvious boon to more precise disease treatment has been available to vascular surgeons for some time, though it has been relatively ignored.&dquo; Because the first smalldiameter angioscopes were evaluated intraoperatively, surgeons took advantage of this bird’s-eye view to check anastomotic sites for suture abnormalities or intimal flaps, 14’11 to assess venous valvotomies on in situ bypass veins,I7,18 to verify the satisfactory performance of endarterectomies,’9 and to monitor thromboembolectomy for more efficacious balloon placement and enhanced removal of adherent thrombus.2o,21 They did not immediately perceive the angioscope’s potential as a preoperative therapeutic tool. Once angioscopes had been sufficiently miniaturized, percutaneous application became feasible .22,2’ Although some investigators have attested to the viability of this percutaneous diagnostic technique in both the peripheral and coronary arteries,22-25 the novelty of this exciting on-the-spot viewing and the interventionist’s somewhat obstinate preference for standard arteriographic imaging have hindered the definition of indications for its use by the very physicians who would benefit most. We began using angioscopy as a curiosity during vascular surgery for evaluation of laser-assisted angioplasty. We soon found, however, that it provided such a superior definition of therapeutic results over contrast imaging that we incorporated it as part of our routine evaluation procedures in peripheral angioplasty and atherectomy. It then occurred to us that we were overlooking several obvious advantages of the device. One was preoperative assessment for the identification of lesion pathology more accurate than that available from the preoperative arteriogram. In the series of patients we report here, the angioscope allowed us to determine that thrombosis alone and not atherosclerotic plaque was responsible for late reocclusion in former angioplasty patients, saving these patients the usually requisite balloon dilation following thrombolysis. Another important aspect to this lesion identification was the ability to determine whether or not stenotic lesions would be amenable to laser ablation, balloon dilation, or atherectomy. Eccentric stenotic lesions are not usually applicable to laser ablation be-
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7
FtG. 4. Biopsy specimens harvested by atherectomy from (A) a balloon-dilated artery and (B) an artery treated with laser-assisted angioplasty. The specimens show identical intimal hyperplasia.
probe follows the contour of the plaque, doing little to debulk the lesion. In these cases, atherectomy or dilation is more efficacious. Similarly, less significant stenotic plaques identified angioscopically following preliminary thrombolysis for occlusion may be sufficiently treated by dilation alone. As an assessment tool following an intervention (laser or atherectomy), angioscopy showed residual plaque that looked nearly untouched by the intervention despite the arteriographic appearance of a satisfactory luminal channel. From this, we could then select further methods that would sufficiently recanalize the artery to our visual satisfaction. We also found the angioscope particularly helpful as a guidance tool. In the larger arteries, both the angioscope and the laser probe or wire could be inserted simultaneously. The angioscope let us see the central channel of even the tightest stenoses for proper passage of the probe. We found the visual assistance for wire guidance valuable when approaching collaterals to keep the wire in the selected lumen. cause
the
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8 In cases of perforation, as was seen in 1 patient from this series, the angioscope assisted in the safe guidance of a wire past the intimal injury on which the wire might have snagged. In this way, further distal treatment could be accomplished without having to abandon the entire recanalization effort, as had been necessary in the past. Of course, all this intraprocedural monitoring assistance was accomplished without increasing the radiation dosage to the patient and staff. Another important use of the angioscope in this series of patients was to assist in the evaluation of restenosis. Because there exists some question of whether the etiology of restenosis after balloon dilation differs from that responsible for restenosis following laser angioplasty, we used the angioscope in a small cohort of patients to identify restenotic lesions without attendant thrombus that could be biopsied for histologic examination. The directional atherectomy catheter is the only recanalization device that cuts away and captures atherosclerotic material, making it ideal for biopsies.26 From several samplings of laser-treated vessels, we found the restenosis to arise from intimal hyperplasia identical to that seen in a lesion treated by balloon dilation only. While it is true that the laser-treated lesions had been dilated subsequent to laser ablation, there was no change in the mechanism of restenosis. It is feasible then to suppose that any injury to the lumen from the tandem treatments was solely related to the balloon, at least in these instances. Of course, it is equally likely that laser treatment induces the same type of intimal hyperplasia. Further evaluation on this point will require specimen samples from restenotic lesions that underwent sole laser therapy, a relatively uncommon occurrence.
Complications with the angioscope have been reported as arterial damage (plaque disruption, perforation), spasm, thrombosis/embolism, and fluid overload&dquo;; however, we encountered no complications attributable to the angioscopic technique. Notably, there was no instance of spasm even as the smaller arteries were approached. Percutaneous angioscopy, which we use whenever feasible, offers several benefits in addition to its diagnostic advantages. First, it does not require the use of contrast material. This makes it quite valuable for diagnosis in patients with demonstrated or suspected allergy to dye. No radiation is involved, an obvious advantage in itself as noted above. The percutaneous access makes it simple to insert without the need for arterial cutdown. Used routinely, we found angioscopy in either mode added no more than ten to fifteen minutes to any procedure. Technically, clear fields are simpler to maintain in the limb arteries with the pulsed infusion pump and suppression of antegrade and retrograde blood flow. Usually the sheath is a sufficient impediment to inflow for percutaneous procedures, but on occasion, the femoral artery must be manually compressed. Retrograde flow is controllable with inflation of the below-knee pressure cuff during observation periods. Moreover, irrigant volume during viewing was markedly reduced with the system’s synchronized pulse administration feature. However, the inability to maintain a clear field in the large-diameter iliac arteries during retrograde passage without contralaterally applied balloon occlusion still precludes the angioscope’s usefulness in this area on a routine basis.
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9
Steerability of the angioscope, which has been a problem in the past, particularly with the longer catheters, is still not perfect. Wire guidance is of use to maintain the optical tip in coaxial alignment for angioscopes equipped with a suitable channel, but we have found that torqueing and retracting the catheter are usually sufficient to reestablish the central position of the flexible percutaneous models. Conclusion
Despite the few technical problems that remain to be solved, we are convinced that angioscopy is a valuable complement to arteriography in both its diagnostic and therapeutic modes, and we recommend its routine inclusion in any intervention program. Edward B. Diethrich, M.D., F.A. C.A., F.I.C.A. Arizona Heart Institute PO Box 10, 000 Phoenix, AZ 85064
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