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Initial results and subsequent outcome of laser thermal-assisted balloon angioplasty of 56 consecutive femoropopliteal lesions
Initial Results and Subsequent Outcome of Laser Thermal-Assisted Balloon Angioplasty of 56 Consecutive Femoropopliteal Lesions Richard L. Feinberg, MD, Jock R. Wheeler, MD, Roger T. Gregory, MD, Stanley O. Snyder, Jr., MD, Robert G. Gayle, MD, F. Noel Parent III, MD, Norfolk,Virginia
Laser thermal-assisted balloon angioplasty (LABA) was prospectively applied in the treatment of 56 atherosclerotic femoropopliteal occlusive lesions in 51 consecutive patients. All procedures were performed in the operating room using a neodyniurn:yttrium-aluminum-garnet (Nd:YAG) laser source, and patients were evaluated for immediate and long-term hemodynamic and clinical improvement. Technically successful recanalization was achieved in 82% of cases, with 57% of all patients (32 of 56) obtaining early hemodynamic and clinical improvement. Long-term clinical success (by life-table analysis) was obtained by only 22.5% at 6 months, and only 13.5% at 12 months. Patients presenting with intermittent claudication did significantly better than those presenting for limb salvage (p = 0.01 ), and trends toward improved outcome were noted for short versus long lesions as well as for patients with "good" versus "poor" distal runoff (NS). Procedure-related morbidity occurred in 14%, and there was one peri-procedural mortality (1.8%). We conclude that the use of LABA is associated with long-term clinical success in only a small proportion of patients, and that widespread clinical application of this technique is not indicated at the present time.
and are being increasingly employed as an alternative to either balloon dilatation alone (porcutanecus transluminal angioplasty, PTA) or formal surgical rcvascularization. Recent reports from a variety of institutions,however, have begun to catalogue more sobering experiences with laser thermal-assisted balloon angioplasty ( L A B A ) as its indications have expanded and as periods of followup observation have been extended [3-7]. Despite the new wave of caution that has arisen in the face of these controversial results,L A B A continues to hold appeal as a potential means of extending the applicabilityof balloon dilatation in selected patients. W e now report the results of our experience utilizing L A B A as the primary therapeutic modality in the treatment of 56 fcmoropopliteal segment lesions.
PATIENTS AND METHODS During the period from April 1, 1988 through July 31, 1989, 51 patients underwent 56 LABA procedures at the Eastern Virginia Graduate School of Medicine Affiliated Hospitals as the primary mode of therapy for symptomatic chronic lower-extremity ischemia. All patients had initially been referred to the Vascular Surgical Service for evaluation of significant, long-standing lower-extremity ischemic symptoms. Following standard noninvasive arterial assessment and lower-extremity arteriography, those patients believed to have hemodynamically significant obstructive lesions of the femoropopliteal segment were approached for participation. Informed consent was obtained from 51 patients, who comprise the group reported herein. The patients ranged in age from 40 to 88 years (mean: 67.2 years). There were 27 men and 24 women, with 3 patients undergoing bilateral procedures and 2 receiving ince Sanborn and co-workers' [1 ] initial report of the repeat procedures for recurrent occlusion following a prein'st FDA-approved trial of laser-assisted peripheral viously successful ipsilateral LABA (56 total procearterial angioplasty in humans, lasers have rapidly at- dures). tained widespread public acceptance as a breakthrough Associated risk factors for arterialdisease were comalternative in the treatment of atherosclerotic occlusive mon, with hypertension and cigarette smoking the two disease. Spurred by encouraging results from a few early most commonly identified (65% and 61%, respectively). series in which hot-tip laser angioplasty was applied to Diabetes mellitus was present in 36% of patients, and a relatively few patients with minimal follow-up [1,2], fi- history of hyl~rcholestcrolemia was documented in 7%. beroptic laser systems have been aggressively marketed Sixty-two percent of patients in this study underwent L A B A for severe,disabling intermittent claudication. All such patients gave a history of the onset of typical leg From the Divisionof Vascular Surgery,Eastern VirginiaGraduate symptoms with less than two blocks' walking, had underSchoolof Medicine,Norfolk,Virginia. Requestsforreprintsshouldbc addressedto Richard L. Feinbcrg, gone a minimum of 6 months of conservative therapy, MD, Divisionof VascularSurgery,EasternVirginiaGraduate School and were otherwise considered candidates for elective ofMedicine,250 W. BrambletonAvenue,Suite101,Norfolk,Virginia surgical revascularization. The remainder of the proce23510. Presentedat the 18thAnnualMeetingof the Societyfor Clinical dures (38%) were performed for threatened limb loss, VascularSurgery,PalmDesert,California,March7-1 l, 1990. with rest pain in I l limbs and ischemic ulceration or
S
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gangrene present in 10. The mean pretreatment anldebrachial index (ABI) for all patients was 0.53 4- 0.14 (range: 0 to 0.85). Thirty-four (61%) of all lesions undergoing LABA consisted of complete arterial occlusionS, while 22 (39%) were high-grade stenoses judged angiographically to consist of greater than 70% diameter reduction. Lesions ranged from 2 cm to greater than 25 cm in length. Twenty of the lesions treated (36%) were less than 5 cm in length and were considered short lesions, while 19 (34%) ranged from 5 to 14 cm (medium) and 17 (30%) measured 15 cm or greater (long). Distal runoff, determined by the number of angiographically demonstrated patent infrapopliteal vessels continuous to the ankle, is listed in Table I. Nineteen patients (37%) had undergone one or more previous vascular reconstructive procedures (n -- 23), 7 of which had been performed on the ipsilateral and 16 on the contralateral extremity. Additionally, 13 LABA procedures (23%) were performed in conjunction with a concomitant procedure to augment inflow. These procedures included common femoral endarterectomy (with or without patch angioplasty) in five patients, iliac artery PTA in four patients, aortohifemoral bypass in two patients, femoro-femoral bypass in one patient, and ipsilateral iliac artery aneurysm repair in one patient. The laser system used throughout this series consisted of a 60-W n e o d y n i u m : y t t r i u m - a l u m i n u m - g a r n e t (Nd:YAG) laser energy source coupled to a sterile, disposable fiberoptic probe with a metal alloy cap (2.0- to 2.5-mm diameter) affixed at the distal end of the fiber. In accordance with the protocol developed for this series, all procedures were performed in the operating suite, with the necessary materials and personnel available and ready to proceed to immediate bypass grafting in the event of an unsuccessful or deleterious LABA attempt. In 10 cases, arterial cannulation was obtained via percutaneous arterial puncture utilizing the Seldinger technique. In the 46 remaining procedures, arterial access was achieved by means of direct surgical cutdown, either because of failed percutaneous attempts (n = 10) or due to individual operator preference (n = 36). Upon successful arterial cannulation, patients received an anticoagulant consisting of intravenously administered heparin (75 to 100 units/kg). Utilizing intra-arterial contrast administration to delineate the proximal extent of the obstruction, attempts were made in all cases to traverse the lesion with a slippery "eel" wire prior to passage of the laser probe. The fiberoptic laser probe was advanced through an 8.5F introducer sheath and down the superficial femoral artery to the point of the lesion, with small amounts of contrast administered at intervals to verify positioning. Five- to 10-second pulses of 12 to 14 W of Nd:YAG laser energy were used to heat the metallic probe, which was then advanced through the lesion with a continuous toand-fro motion under constant fluoroscopic surveillance. Probe passage was continued until successful recanalization was documented angiographically, further probe progress was believed to be impossible, or vessel perforation rendered additional manipulation too hazardous.
TABLE I
Patent Infrapopllteal Runoff Vessels in Extremities Undergoing LABA No. of Patent Runoff Vessels
No. of Patients (%)
0 1 2 3
4 (7) 17 (30) 17 (30) 18 (32)
Following all successful re,canalizations, standard balloon dilatation (utilizing balloons 5 to 6 mm in diameter) was performed to create a wider channel than that resulting from passage of the 2.0- to 2.5-mm probes alone. Completion arteriography was performed following balloon dilatation in all cases and was used in evaluating results. Upon completion of the procedure, all patients were maintained on a low-dose heparin infusion for 24 hours, after which antiplatelet therapy was instituted with aspirin, 325 mg daily, and was continued throughout the follow-up period. Patients were seen within 1 month of hospital discharge and then subsequently at 2 to 3 months and 6, 9, and 12 months postoperatively. For those patients followed beyond 1 year, office visits averaged every 3 to 6 months thereafter. At all follow-up evaluations, a thorough history and physical examination were performed and ABIs were recorded for each patient. Each LABA procedure was evaluated on the basis of technical, hemodynamic, and clinical success or failure. Procedures were determined to have been technically successful on the basis of completion arteriography if either a continuous, patent channel was reestablished in a previously occluded artery, or improvement in luminal diameter to less than 50% residual stenosis was noted in a previously tightly stenotic arterial segment. LABA was categorized a hemodynamic success if posttreatment ABI measurements documented an increase of 0.15 or greater over the pretreatment index. A procedure was considered a clinical success if there was subjective improvement recorded in a patient's baseline claudication pattern or documented healing of ischemic lesions. Assessment of long-term cumulative clinical patency was performed by Kaplan-Meier life-table analysis, with procedures judged a failure if there was subsequent decrement of a prior hemodynamic improvement or if deterioration of the clinical status of a treated extremity was identified. Comparison of life-table patency curves was performed by means of the Mantel-Haenszel log-rank test. RESULTS Follow-up ranged from 3 days to 16.5 months (mean: 8.6 4- 4.2 months). Technical success was achieved in 46 of 56 LABA attempts (82%), with immediate hemodynamic success obtained in 32 of 46 (70%) technically successful procedures, for an overall hemodynamic success rate of 57% (32 of 56 attempts). Life-table depiction of long-term cumulative clinical success for all patients, as well as for initially successful procedures only, is reprr
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sentcd in Figure 1. Exclusion of immediate technical failures in construction of the life tables resulted in an adjusted 1-year success rate of 24% compared with 13.5% when all patients are considered. Specific subgroup analysis revealed no significant outcome advantage based on the presence or absence of individual risk factors (diabetes, hypertension, or tobacco use) nor on the basis of a history of prior vascular interventions. Among the 35 patients presenting with intermittent claudication as their indication for intervention, initial technical and hemodynamic success was achieved in 24 (69%) compared with an initial technical/hemodynamic suec~s rate of 38% (8 of 21 patients) among those presenting for limb salvage. Figure 2 depicts the life-table curves for these two groups, demonstrating 6- and 12month cumulative clinical success rates of 37% and 22%, respectively, for patients with intermittent claudication and 0% at both 6 and 12 months for patients presenting for limb salvage (p -- 0.01). Twenty-three of 34 complete occlusions were successfully recanalized (68%), while 22 of 22 tight stcnoscs achieved initial technical/hemodynamic success (100%) following LABA. There was no statistically significant difference between these two groups with regard to longterm success (p >0.6). Short lesions (less than 5 cm) appeared to fare better than long lesions (greater than 15 cm), with 16 of 20 (80%) of the former achieving initial technical/hemodynamic success, compared with only 4 of 17 (24%) initial successes among the latter. Life-table comparison of long-term success between these groups demonstrated a trend in favor of short lesions that did not attain statistical significance (p -- 0.09). LABA met with initial technical/hemodynamic success in 9 of 21 (43%) patients categorized as having poor 168
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distal runoff (either an isolated popliteal segment or a single patent infrapopliteal vessel) compared with 23 of 35 initial successes (66%) among patients with good runoff (2 or 3 patent infrapoplitcal vessels). This trend favoring the group with good runoff also failed to attain statistical significance (p -- 0.08). Eight complications of LABA were recorded during the course of the study, yielding a procedure-related morbidity rate of 14%. Complications included three intimal dissections, two vessel perforations, and one instance each of groin hematoma, lymphoccle, and wound infection. In only two cases was operative intervention required, once for intimal dissection and once for the groin lymphoccle that had failed to respond to nonoperative measures. Three extremities treated by LABA ultimately required major amputation (two below-knee, one above-knee); two of these patients had refused formal vascular reconstruction following failed LABA, and one patient underwent distal bypass grafting with eventual graft occlusion and subsequent amputation. All three amputations occurred in patients presenting with ischemic tissue loss. Fourteen patients underwent immediate surgical revascularization at the time of a failed LABA, and 15 additional patients required 1 or more vascular reconstructions during the follow-up period at a mean of 2.9 months following the initial procedure. One patient died within 30 days of LABA, yielding a peri-procedural mortality rate of 1.8%. COMMENTS Since Sanborn and co-workers [1] first reported initial hemodynamic and clinical success in 12 of 15 patients (80%) treated with a hot-tip catheter for femoropopliteal segment lesions, numerous investigators have reported varying rates of success with the use of LABA [2-7].
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With expanded indications and longer-term follow-up, a diminution of success rates has been documented [5], with two recent reports demonstrating 12-month cumulative patency rates of 29% and 32% [6,7]. In the present series, successful recanalization was achieved in 82% of extremities with LABA, resulting in short-term hemodynamic and clinical success in 57% of cases overall. However, life-table analysis of the subsequent fate of LABA-treated arteries revealed an abrupt occurrence of early failure, with 6- and 12-month cumulative clinical patency rates a dismal 23% and 14%, respectively, with a mean time to restenosis of 2.7 months. These results, both initial as well as long-term, are consistent with those recently reported by other authors and compare unfavorably with results reported for PTA alone in the treatment of similar lesions [8,9]. Indication for treatment was the only factor that reliably correlated with the likelihood of a successful outcome of LABA in this series; patients presenting for treatment of intermittent claudication achieved significantly better succ~s rates than those presenting for limb salvage (p = 0.01). Two additional factors appeared to correlate with a successful result: patients with shorter lesions seemed to fare better than those with long lesions (p = 0.09), and patients with good distal runoff were likelier to achieve long-term success following LABA than were those with poor runoff (p = 0.08). Unfortunately, neither of these trends attained statistical significance. When considered together, these factors indicate that patients most likely to obtain a satisfactory result from LABA would be those with discrete, short-segment lesions, two- or three-vessel outflow, and milder symptoms, representing an overall less advanced degree of ischemia. It remains to be seen whether LABA, applied to a group of patients with these characteristics, would consistently achieve satisfactory patency rates. A prospective, randomized trial comparing LABA with PTA in such a patient population is required to determine What role laser-thermal techniques should play in the future. A disquieting observation regarding LABA is the aggressive tendency to early restenosis seen in this and other recent series. Studies in animal models over short time intervals have demonstrated larger residual lumina and lower rates of restenosis among arteries subjected to laser-thermal probe recanalization compared with those undergoing balloon angioplasty [10]. Other studies, however, have consistently documented histopathologic evidence of intimal and medial burn injury in arteries subjected to laser-thermal recanalization, with charring and vacuolization involving the inner layers of the arterial wall and a subsequent fibrocellular proliferative ingrowth [11-14]. Laser-induced thermal injury of the arterial wall, transmitted across the atheroma and eliciting a hyperplastic cellular response, may indeed account for the discouraging propensity to restenosis observed within 2 to 3 months in this and other clinical trials. On the basis of our experience, as well as that recently reported by others, we believe that the growing body of clinical data does not support the routine use of LABA in the treatment of peripheral arterial occlusive disease, and
that these techniques remain investigational in nature at the present time. We were able to identify a subset of patients--those with minimal lesions, good runoff, and mild ischemic symptoms--who appear to comprise the group most likely, if any, to benefit from the use of LABA. Whether this technique will seriously challenge PTA as the superior method of treatment for this select group of patients must await a prospective, randomized evaluation of these two modalities. There is no evidence, at present, to support the use of LABA as an alternative mode of therapy in patients requiring formal infrainguinal bypass grafting for the treatment of more advanced cases of chronic lower-extremity ischemia. REFERENCES 1. SanbornTA, Greenfield AJ, Guben JK, Menzoian JO, LoGerfo FW. Human pereutaneous and intraoperative laser thermal angioplasty: initial clinical results as an adjunct to balloon angioplasty. J Vase Surg 1987; 5: 83-90. 2. McCowan TC, Ferris EJ, Barnes RW, Baker ML. Laser thermal angioplasty for the treatment of obstruction of the distal superficial femoral or popliteal arteries. AJR 1988; 150:1169-73. 3. Matsumoto T, Okamura T, Rajyaguru V. Laser arterial disobstrnctive procedures in 148 lower extremities. J Vase Surg 1989; 10: 169-77. 4. Seeger JM, Abela GS, Silverman SH, Jablonski SK. Initial results of laser recanalization in lower extremity arterial reconstruction. J Vase Surg 1989; 9: 10-7. 5. Wright JG, Belkin M, Greenfield AJ, Guben JK, Sanborn TA, Menzoian JO. Laser angioplasty for limb salvage: observations on early results. J Vase Surg 1989; 10: 29-38. 6. Perler BA, Osterman FA, White RI, Williams GM. Percutaneous laser probe femoropopliteal angioplasty: a preliminary experience. J Vase Surg 1989; 10: 351-7. 7. Harrington ME, Schwartz ME, Sanborn TA, et al. Expanded indications for laser-assisted balloon angioplasty in peripheral arterial disease. J Vase Surg 1990; 11: 146-55. 8. Krepel VM, van Andel GJ, van Erp WF, Breslau PJ. Percutaneous transluminal angioplasty of the femoropepliteal artery: initial and long-term results. Radiology 1985; 156: 325-8. 9. Hewes RC, White RI, Murray RR, et al. Long-term results of superficial femoral artery angioplasty. AJR 1986; 146: 1025-9. 10. Sanborn TA, Haudensehild CC, Garber GR, Ryan TJ, Faxon DP. Angiographic and histologic consequences of laser thermal angioplasty: comparison with balloon angioplasty. Circulation 1987; 75: 1281-6. 11. Sanborn TA, Faxon DP, Haudenschild CC, Ryan TJ. Experimental angioplasty: circumferential distribution of laser thermal energy with a laser probe. J Am Coil Cardiol 1985; 5: 934-8. 12. Gerrity RG, Loop FD, Golding LA, Ehrhart LA, Argenyi ZB. Arterial response to laser operation for removal of atherosclerotic plaques. J Thorac Cardiovasc Surg 1983; 85: 409-21. 13. Gesehwind H, Fabre M, Chaitman BR, et al. Histopathology after Nd-YAG laser percutaneous transluminal angioplasty of peripheral arteries. J Am Coil Cardiol 1986; 8: 1089-95. 14. Grundfest WS, Litvack F, Forrester JS, et aL Laser ablation of human atherosclerotic plaque without adjacent tissue injury. J Am Coil Cardiol 1985; 5: 929-33.
DISCUSSION John u White (Philadelphia, PA): Dr. Feinberg, were all lesions traversed by the guide wire prior to the use of the laser, and did the success or failure of the procedure depend on successful crossing of the lesion by the guide wire? In terms of lesion location, did you find that mid-body
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superficial femoral artery lesions were more easily crossed with the guide wire and more successfully treated than orificial stenoses or stenoses of Hunter's canal, which often can be difficult to dilate with the balloon? What were the long-term results for the calcific lesions after dilation? Is this related to the possibility that the cracked calelfic shell can stent open the lumen? In patients who have elaudication with short lesions and good runoff, those who had the most favorable prognosis, what were the long-term results of the new technology? I am concerned about your statement that this technology may be suitable for patients who are poor surgical risks. We have confined the use of this technology to those patients who are excellent surgical risks so that they may be treated without excessive morbidity or mortality should unforeseen complications arise. What are your future plans for this technology, and what type of patient will you be willing to treat with it? Richard Feinberg (closing): Dr. White, in the 34 patients with completely occlusive lesions, we were able to traverse 19 lesions with the guidewirr while 15 could not be crossed. Of these latter 15 lesions, 10 were successfully opened with the laser. As to the locations of the lesions, we excluded orificial lesions since they have been shown
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previously to be the least amenable to therapy. We addressed only mid-body and Hunter's canal lesions of the superficial femoral artery. We do not have any long-term data regarding durability of repair in calcific lesions. Regarding the long-term results in patients with the most favorable characteristics, i.e., claudication, short lesions, and good run-off, I would point out that all three of these factors were present in each of our long-term successes. We had mixed feelings regarding the use of this technique in patients who had limb-threatening ischemia but were poor surgical risks. While we believe that most such patients can, in fact, tolerate formal surgical reconstruction, we felt that a limited exposure of the femoral artery in the groin under local anesthesia would allow a laser angioplasty to be carried out with minimal morbidity and mortality. At the present time, we have stopped using LABA because we consider the extremely high rate of early restenosis to be prohibitive, and we believe that PTA alone is sufficient for lesions that can be traversed with a guidewire. We continue to view with optimism the current development of nonthermal lasing systems, particularly the pulsed ultraviolet lasers, as an alternate means of performing rexanalization with less trauma to the arterial wall.
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Laser thermal-assisted balloon angioplasty (LABA) was prospectively applied in the treatment of 56 atherosclerotic femoropopliteal occlusive lesions in 51 consecutive patients. All procedures were performed in the operating room using a neodyniurn:yttrium-aluminum-garnet (Nd:YAG) laser source, and patients were evaluated for immediate and long-term hemodynamic and clinical improvement. Technically successful recanalization was achieved in 82% of cases, with 57% of all patients (32 of 56) obtaining early hemodynamic and clinical improvement. Long-term clinical success (by life-table analysis) was obtained by only 22.5% at 6 months, and only 13.5% at 12 months. Patients presenting with intermittent claudication did significantly better than those presenting for limb salvage (p = 0.01 ), and trends toward improved outcome were noted for short versus long lesions as well as for patients with "good" versus "poor" distal runoff (NS). Procedure-related morbidity occurred in 14%, and there was one peri-procedural mortality (1.8%). We conclude that the use of LABA is associated with long-term clinical success in only a small proportion of patients, and that widespread clinical application of this technique is not indicated at the present time.
and are being increasingly employed as an alternative to either balloon dilatation alone (porcutanecus transluminal angioplasty, PTA) or formal surgical rcvascularization. Recent reports from a variety of institutions,however, have begun to catalogue more sobering experiences with laser thermal-assisted balloon angioplasty ( L A B A ) as its indications have expanded and as periods of followup observation have been extended [3-7]. Despite the new wave of caution that has arisen in the face of these controversial results,L A B A continues to hold appeal as a potential means of extending the applicabilityof balloon dilatation in selected patients. W e now report the results of our experience utilizing L A B A as the primary therapeutic modality in the treatment of 56 fcmoropopliteal segment lesions.
PATIENTS AND METHODS During the period from April 1, 1988 through July 31, 1989, 51 patients underwent 56 LABA procedures at the Eastern Virginia Graduate School of Medicine Affiliated Hospitals as the primary mode of therapy for symptomatic chronic lower-extremity ischemia. All patients had initially been referred to the Vascular Surgical Service for evaluation of significant, long-standing lower-extremity ischemic symptoms. Following standard noninvasive arterial assessment and lower-extremity arteriography, those patients believed to have hemodynamically significant obstructive lesions of the femoropopliteal segment were approached for participation. Informed consent was obtained from 51 patients, who comprise the group reported herein. The patients ranged in age from 40 to 88 years (mean: 67.2 years). There were 27 men and 24 women, with 3 patients undergoing bilateral procedures and 2 receiving ince Sanborn and co-workers' [1 ] initial report of the repeat procedures for recurrent occlusion following a prein'st FDA-approved trial of laser-assisted peripheral viously successful ipsilateral LABA (56 total procearterial angioplasty in humans, lasers have rapidly at- dures). tained widespread public acceptance as a breakthrough Associated risk factors for arterialdisease were comalternative in the treatment of atherosclerotic occlusive mon, with hypertension and cigarette smoking the two disease. Spurred by encouraging results from a few early most commonly identified (65% and 61%, respectively). series in which hot-tip laser angioplasty was applied to Diabetes mellitus was present in 36% of patients, and a relatively few patients with minimal follow-up [1,2], fi- history of hyl~rcholestcrolemia was documented in 7%. beroptic laser systems have been aggressively marketed Sixty-two percent of patients in this study underwent L A B A for severe,disabling intermittent claudication. All such patients gave a history of the onset of typical leg From the Divisionof Vascular Surgery,Eastern VirginiaGraduate symptoms with less than two blocks' walking, had underSchoolof Medicine,Norfolk,Virginia. Requestsforreprintsshouldbc addressedto Richard L. Feinbcrg, gone a minimum of 6 months of conservative therapy, MD, Divisionof VascularSurgery,EasternVirginiaGraduate School and were otherwise considered candidates for elective ofMedicine,250 W. BrambletonAvenue,Suite101,Norfolk,Virginia surgical revascularization. The remainder of the proce23510. Presentedat the 18thAnnualMeetingof the Societyfor Clinical dures (38%) were performed for threatened limb loss, VascularSurgery,PalmDesert,California,March7-1 l, 1990. with rest pain in I l limbs and ischemic ulceration or
S
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gangrene present in 10. The mean pretreatment anldebrachial index (ABI) for all patients was 0.53 4- 0.14 (range: 0 to 0.85). Thirty-four (61%) of all lesions undergoing LABA consisted of complete arterial occlusionS, while 22 (39%) were high-grade stenoses judged angiographically to consist of greater than 70% diameter reduction. Lesions ranged from 2 cm to greater than 25 cm in length. Twenty of the lesions treated (36%) were less than 5 cm in length and were considered short lesions, while 19 (34%) ranged from 5 to 14 cm (medium) and 17 (30%) measured 15 cm or greater (long). Distal runoff, determined by the number of angiographically demonstrated patent infrapopliteal vessels continuous to the ankle, is listed in Table I. Nineteen patients (37%) had undergone one or more previous vascular reconstructive procedures (n -- 23), 7 of which had been performed on the ipsilateral and 16 on the contralateral extremity. Additionally, 13 LABA procedures (23%) were performed in conjunction with a concomitant procedure to augment inflow. These procedures included common femoral endarterectomy (with or without patch angioplasty) in five patients, iliac artery PTA in four patients, aortohifemoral bypass in two patients, femoro-femoral bypass in one patient, and ipsilateral iliac artery aneurysm repair in one patient. The laser system used throughout this series consisted of a 60-W n e o d y n i u m : y t t r i u m - a l u m i n u m - g a r n e t (Nd:YAG) laser energy source coupled to a sterile, disposable fiberoptic probe with a metal alloy cap (2.0- to 2.5-mm diameter) affixed at the distal end of the fiber. In accordance with the protocol developed for this series, all procedures were performed in the operating suite, with the necessary materials and personnel available and ready to proceed to immediate bypass grafting in the event of an unsuccessful or deleterious LABA attempt. In 10 cases, arterial cannulation was obtained via percutaneous arterial puncture utilizing the Seldinger technique. In the 46 remaining procedures, arterial access was achieved by means of direct surgical cutdown, either because of failed percutaneous attempts (n = 10) or due to individual operator preference (n = 36). Upon successful arterial cannulation, patients received an anticoagulant consisting of intravenously administered heparin (75 to 100 units/kg). Utilizing intra-arterial contrast administration to delineate the proximal extent of the obstruction, attempts were made in all cases to traverse the lesion with a slippery "eel" wire prior to passage of the laser probe. The fiberoptic laser probe was advanced through an 8.5F introducer sheath and down the superficial femoral artery to the point of the lesion, with small amounts of contrast administered at intervals to verify positioning. Five- to 10-second pulses of 12 to 14 W of Nd:YAG laser energy were used to heat the metallic probe, which was then advanced through the lesion with a continuous toand-fro motion under constant fluoroscopic surveillance. Probe passage was continued until successful recanalization was documented angiographically, further probe progress was believed to be impossible, or vessel perforation rendered additional manipulation too hazardous.
TABLE I
Patent Infrapopllteal Runoff Vessels in Extremities Undergoing LABA No. of Patent Runoff Vessels
No. of Patients (%)
0 1 2 3
4 (7) 17 (30) 17 (30) 18 (32)
Following all successful re,canalizations, standard balloon dilatation (utilizing balloons 5 to 6 mm in diameter) was performed to create a wider channel than that resulting from passage of the 2.0- to 2.5-mm probes alone. Completion arteriography was performed following balloon dilatation in all cases and was used in evaluating results. Upon completion of the procedure, all patients were maintained on a low-dose heparin infusion for 24 hours, after which antiplatelet therapy was instituted with aspirin, 325 mg daily, and was continued throughout the follow-up period. Patients were seen within 1 month of hospital discharge and then subsequently at 2 to 3 months and 6, 9, and 12 months postoperatively. For those patients followed beyond 1 year, office visits averaged every 3 to 6 months thereafter. At all follow-up evaluations, a thorough history and physical examination were performed and ABIs were recorded for each patient. Each LABA procedure was evaluated on the basis of technical, hemodynamic, and clinical success or failure. Procedures were determined to have been technically successful on the basis of completion arteriography if either a continuous, patent channel was reestablished in a previously occluded artery, or improvement in luminal diameter to less than 50% residual stenosis was noted in a previously tightly stenotic arterial segment. LABA was categorized a hemodynamic success if posttreatment ABI measurements documented an increase of 0.15 or greater over the pretreatment index. A procedure was considered a clinical success if there was subjective improvement recorded in a patient's baseline claudication pattern or documented healing of ischemic lesions. Assessment of long-term cumulative clinical patency was performed by Kaplan-Meier life-table analysis, with procedures judged a failure if there was subsequent decrement of a prior hemodynamic improvement or if deterioration of the clinical status of a treated extremity was identified. Comparison of life-table patency curves was performed by means of the Mantel-Haenszel log-rank test. RESULTS Follow-up ranged from 3 days to 16.5 months (mean: 8.6 4- 4.2 months). Technical success was achieved in 46 of 56 LABA attempts (82%), with immediate hemodynamic success obtained in 32 of 46 (70%) technically successful procedures, for an overall hemodynamic success rate of 57% (32 of 56 attempts). Life-table depiction of long-term cumulative clinical success for all patients, as well as for initially successful procedures only, is reprr
THE AMERICAN JOURNAL OF SURGERY
VOLUME 160
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167
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Months Figure 1. Cumulative clinical success of LABA for all patients (squares) and for initially successful procedures only (dots). Numbers in parentheses represent patients at risk for each time interval.
sentcd in Figure 1. Exclusion of immediate technical failures in construction of the life tables resulted in an adjusted 1-year success rate of 24% compared with 13.5% when all patients are considered. Specific subgroup analysis revealed no significant outcome advantage based on the presence or absence of individual risk factors (diabetes, hypertension, or tobacco use) nor on the basis of a history of prior vascular interventions. Among the 35 patients presenting with intermittent claudication as their indication for intervention, initial technical and hemodynamic success was achieved in 24 (69%) compared with an initial technical/hemodynamic suec~s rate of 38% (8 of 21 patients) among those presenting for limb salvage. Figure 2 depicts the life-table curves for these two groups, demonstrating 6- and 12month cumulative clinical success rates of 37% and 22%, respectively, for patients with intermittent claudication and 0% at both 6 and 12 months for patients presenting for limb salvage (p -- 0.01). Twenty-three of 34 complete occlusions were successfully recanalized (68%), while 22 of 22 tight stcnoscs achieved initial technical/hemodynamic success (100%) following LABA. There was no statistically significant difference between these two groups with regard to longterm success (p >0.6). Short lesions (less than 5 cm) appeared to fare better than long lesions (greater than 15 cm), with 16 of 20 (80%) of the former achieving initial technical/hemodynamic success, compared with only 4 of 17 (24%) initial successes among the latter. Life-table comparison of long-term success between these groups demonstrated a trend in favor of short lesions that did not attain statistical significance (p -- 0.09). LABA met with initial technical/hemodynamic success in 9 of 21 (43%) patients categorized as having poor 168
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distal runoff (either an isolated popliteal segment or a single patent infrapopliteal vessel) compared with 23 of 35 initial successes (66%) among patients with good runoff (2 or 3 patent infrapoplitcal vessels). This trend favoring the group with good runoff also failed to attain statistical significance (p -- 0.08). Eight complications of LABA were recorded during the course of the study, yielding a procedure-related morbidity rate of 14%. Complications included three intimal dissections, two vessel perforations, and one instance each of groin hematoma, lymphoccle, and wound infection. In only two cases was operative intervention required, once for intimal dissection and once for the groin lymphoccle that had failed to respond to nonoperative measures. Three extremities treated by LABA ultimately required major amputation (two below-knee, one above-knee); two of these patients had refused formal vascular reconstruction following failed LABA, and one patient underwent distal bypass grafting with eventual graft occlusion and subsequent amputation. All three amputations occurred in patients presenting with ischemic tissue loss. Fourteen patients underwent immediate surgical revascularization at the time of a failed LABA, and 15 additional patients required 1 or more vascular reconstructions during the follow-up period at a mean of 2.9 months following the initial procedure. One patient died within 30 days of LABA, yielding a peri-procedural mortality rate of 1.8%. COMMENTS Since Sanborn and co-workers [1] first reported initial hemodynamic and clinical success in 12 of 15 patients (80%) treated with a hot-tip catheter for femoropopliteal segment lesions, numerous investigators have reported varying rates of success with the use of LABA [2-7].
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With expanded indications and longer-term follow-up, a diminution of success rates has been documented [5], with two recent reports demonstrating 12-month cumulative patency rates of 29% and 32% [6,7]. In the present series, successful recanalization was achieved in 82% of extremities with LABA, resulting in short-term hemodynamic and clinical success in 57% of cases overall. However, life-table analysis of the subsequent fate of LABA-treated arteries revealed an abrupt occurrence of early failure, with 6- and 12-month cumulative clinical patency rates a dismal 23% and 14%, respectively, with a mean time to restenosis of 2.7 months. These results, both initial as well as long-term, are consistent with those recently reported by other authors and compare unfavorably with results reported for PTA alone in the treatment of similar lesions [8,9]. Indication for treatment was the only factor that reliably correlated with the likelihood of a successful outcome of LABA in this series; patients presenting for treatment of intermittent claudication achieved significantly better succ~s rates than those presenting for limb salvage (p = 0.01). Two additional factors appeared to correlate with a successful result: patients with shorter lesions seemed to fare better than those with long lesions (p = 0.09), and patients with good distal runoff were likelier to achieve long-term success following LABA than were those with poor runoff (p = 0.08). Unfortunately, neither of these trends attained statistical significance. When considered together, these factors indicate that patients most likely to obtain a satisfactory result from LABA would be those with discrete, short-segment lesions, two- or three-vessel outflow, and milder symptoms, representing an overall less advanced degree of ischemia. It remains to be seen whether LABA, applied to a group of patients with these characteristics, would consistently achieve satisfactory patency rates. A prospective, randomized trial comparing LABA with PTA in such a patient population is required to determine What role laser-thermal techniques should play in the future. A disquieting observation regarding LABA is the aggressive tendency to early restenosis seen in this and other recent series. Studies in animal models over short time intervals have demonstrated larger residual lumina and lower rates of restenosis among arteries subjected to laser-thermal probe recanalization compared with those undergoing balloon angioplasty [10]. Other studies, however, have consistently documented histopathologic evidence of intimal and medial burn injury in arteries subjected to laser-thermal recanalization, with charring and vacuolization involving the inner layers of the arterial wall and a subsequent fibrocellular proliferative ingrowth [11-14]. Laser-induced thermal injury of the arterial wall, transmitted across the atheroma and eliciting a hyperplastic cellular response, may indeed account for the discouraging propensity to restenosis observed within 2 to 3 months in this and other clinical trials. On the basis of our experience, as well as that recently reported by others, we believe that the growing body of clinical data does not support the routine use of LABA in the treatment of peripheral arterial occlusive disease, and
that these techniques remain investigational in nature at the present time. We were able to identify a subset of patients--those with minimal lesions, good runoff, and mild ischemic symptoms--who appear to comprise the group most likely, if any, to benefit from the use of LABA. Whether this technique will seriously challenge PTA as the superior method of treatment for this select group of patients must await a prospective, randomized evaluation of these two modalities. There is no evidence, at present, to support the use of LABA as an alternative mode of therapy in patients requiring formal infrainguinal bypass grafting for the treatment of more advanced cases of chronic lower-extremity ischemia. REFERENCES 1. SanbornTA, Greenfield AJ, Guben JK, Menzoian JO, LoGerfo FW. Human pereutaneous and intraoperative laser thermal angioplasty: initial clinical results as an adjunct to balloon angioplasty. J Vase Surg 1987; 5: 83-90. 2. McCowan TC, Ferris EJ, Barnes RW, Baker ML. Laser thermal angioplasty for the treatment of obstruction of the distal superficial femoral or popliteal arteries. AJR 1988; 150:1169-73. 3. Matsumoto T, Okamura T, Rajyaguru V. Laser arterial disobstrnctive procedures in 148 lower extremities. J Vase Surg 1989; 10: 169-77. 4. Seeger JM, Abela GS, Silverman SH, Jablonski SK. Initial results of laser recanalization in lower extremity arterial reconstruction. J Vase Surg 1989; 9: 10-7. 5. Wright JG, Belkin M, Greenfield AJ, Guben JK, Sanborn TA, Menzoian JO. Laser angioplasty for limb salvage: observations on early results. J Vase Surg 1989; 10: 29-38. 6. Perler BA, Osterman FA, White RI, Williams GM. Percutaneous laser probe femoropopliteal angioplasty: a preliminary experience. J Vase Surg 1989; 10: 351-7. 7. Harrington ME, Schwartz ME, Sanborn TA, et al. Expanded indications for laser-assisted balloon angioplasty in peripheral arterial disease. J Vase Surg 1990; 11: 146-55. 8. Krepel VM, van Andel GJ, van Erp WF, Breslau PJ. Percutaneous transluminal angioplasty of the femoropepliteal artery: initial and long-term results. Radiology 1985; 156: 325-8. 9. Hewes RC, White RI, Murray RR, et al. Long-term results of superficial femoral artery angioplasty. AJR 1986; 146: 1025-9. 10. Sanborn TA, Haudensehild CC, Garber GR, Ryan TJ, Faxon DP. Angiographic and histologic consequences of laser thermal angioplasty: comparison with balloon angioplasty. Circulation 1987; 75: 1281-6. 11. Sanborn TA, Faxon DP, Haudenschild CC, Ryan TJ. Experimental angioplasty: circumferential distribution of laser thermal energy with a laser probe. J Am Coil Cardiol 1985; 5: 934-8. 12. Gerrity RG, Loop FD, Golding LA, Ehrhart LA, Argenyi ZB. Arterial response to laser operation for removal of atherosclerotic plaques. J Thorac Cardiovasc Surg 1983; 85: 409-21. 13. Gesehwind H, Fabre M, Chaitman BR, et al. Histopathology after Nd-YAG laser percutaneous transluminal angioplasty of peripheral arteries. J Am Coil Cardiol 1986; 8: 1089-95. 14. Grundfest WS, Litvack F, Forrester JS, et aL Laser ablation of human atherosclerotic plaque without adjacent tissue injury. J Am Coil Cardiol 1985; 5: 929-33.
DISCUSSION John u White (Philadelphia, PA): Dr. Feinberg, were all lesions traversed by the guide wire prior to the use of the laser, and did the success or failure of the procedure depend on successful crossing of the lesion by the guide wire? In terms of lesion location, did you find that mid-body
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superficial femoral artery lesions were more easily crossed with the guide wire and more successfully treated than orificial stenoses or stenoses of Hunter's canal, which often can be difficult to dilate with the balloon? What were the long-term results for the calcific lesions after dilation? Is this related to the possibility that the cracked calelfic shell can stent open the lumen? In patients who have elaudication with short lesions and good runoff, those who had the most favorable prognosis, what were the long-term results of the new technology? I am concerned about your statement that this technology may be suitable for patients who are poor surgical risks. We have confined the use of this technology to those patients who are excellent surgical risks so that they may be treated without excessive morbidity or mortality should unforeseen complications arise. What are your future plans for this technology, and what type of patient will you be willing to treat with it? Richard Feinberg (closing): Dr. White, in the 34 patients with completely occlusive lesions, we were able to traverse 19 lesions with the guidewirr while 15 could not be crossed. Of these latter 15 lesions, 10 were successfully opened with the laser. As to the locations of the lesions, we excluded orificial lesions since they have been shown
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previously to be the least amenable to therapy. We addressed only mid-body and Hunter's canal lesions of the superficial femoral artery. We do not have any long-term data regarding durability of repair in calcific lesions. Regarding the long-term results in patients with the most favorable characteristics, i.e., claudication, short lesions, and good run-off, I would point out that all three of these factors were present in each of our long-term successes. We had mixed feelings regarding the use of this technique in patients who had limb-threatening ischemia but were poor surgical risks. While we believe that most such patients can, in fact, tolerate formal surgical reconstruction, we felt that a limited exposure of the femoral artery in the groin under local anesthesia would allow a laser angioplasty to be carried out with minimal morbidity and mortality. At the present time, we have stopped using LABA because we consider the extremely high rate of early restenosis to be prohibitive, and we believe that PTA alone is sufficient for lesions that can be traversed with a guidewire. We continue to view with optimism the current development of nonthermal lasing systems, particularly the pulsed ultraviolet lasers, as an alternate means of performing rexanalization with less trauma to the arterial wall.
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