411 CLINICAL INVESTIGATION Subintimal Angioplasty of Isolated Infragenicular Vessels in Lower Limb Ischemia: Long-term Results Hemant Ingle, MS, FRCS; Ahktar Nasim, MD, FRCS; Amman Bolia, FRCR; Guy Fishwick, FRCR*; Ross Naylor,MD, FRCS; Peter R.F.Bell, MD, FRCS; and Matthew M. Thompson, MD, FRCS Departments of Surgery and *Radiology, Leicester Royal Infirmary, Leicester, England, UK Purpose: To assess the outcome of subintimal angioplasty in treating isolated infragenicular arterial disease in patients with severe lower limb ischemia. Methods: A retrospective study reviewed 67 consecutive patients (39 men; mean age 76 years, range 41 96) who underwent infragenicular subintimal angioplasty between March 1997 and May 2000 for ischemia in 70 limbs. The median length of occlusion was 6cm (range 1 10) in the below-knee popliteal arteries, 4cm (range 1 4) in the tibioperoneal trunk, 21 cm (range 1 35) in the anterior tibial artery,10 (1 30)intheposteriortibialartery, and 5 (range 1 20) in the peroneal artery. Results: The technical and clinical success rates were 86% and 80%, respectively. In the 10 (14%) patients with a technical failure, 3 underwent successful bypass, 4 had an amputation, 1 had a lumbar sympathectomy, and 2 were treated conservatively. Of the 4 (6%) limbs that did not achieve clinical success, 2 patients required femorodistal bypass and their ulcers improved; in the other 2, ulcerations did not heal completely. The cumulative limb salvage rate and freedom from critical limb ischemia (CLI) quantified by Kaplan-Meier life-table analysis were 94% and 84% at 36 months. Mortality rates were 19% at 1 year, 43% at 2 years, and 51% at 3 years. In a subgroup analysis, the rate of CLI was significantly lower in nondiabetics (4%) and than in diabetics (24%, p0.02), but neither survival nor amputation rates were significantly different. Conclusions: Subintimal angioplasty is a safe and effective procedure for treating isolated crural vessels in patients with severe lower limb ischemia. J Endovasc Ther Key words: crural arteries, balloon dilation, chronic limb ischemia, survival Twenty-seven percent of patients with severe limb ischemia have infragenicular disease. 1 Below-knee occlusive disease is more prevalent in diabetics (36% 49%) 2,3 and is also a common feature in patients with Buerger s disease. 4 Prior to the widespread adoption of endovascular techniques, these patients were treated either conservatively or underwent popliteal-pedal bypass. In general, results of bypass surgery have been relatively poor, with a 2-year primary patency rate of 55% and a 12% amputation rate. 5 Even after angioplasty became a well established therapy, it was often deemed unsuitable in the infragenicular vessels because of their small caliber, tendency to develop spasm, and in failed cases, a poorer surgical outcome. 6,7 A little over a decade ago, the technique of subintimal angioplasty was first tried with good success in the femoropopliteal seg- Address for correspondence and reprints: Mr. M.M. Thompson, MD, FRCS, Consultant Vascular and Endovascular Surgeon, Clinical Sciences Building, Leicester Royal Infirmary, Leicester LE2 7LX, England, UK. Fax: 44-116-2523179; E-mail: MattT11@aol.com 2002 by the INTERNATIONAL SOCIETY OF ENDOVASCULAR SPECIALISTS Available at www.jevt.org
412 SUBINTIMAL ANGIOPLASTY ment. 8 In the last few years, it has been increasingly applied to infragenicular disease. 9 11 The aim of this study was to evaluate the outcome of isolated infragenicular subintimal angioplasty with reference to technical success and limb salvage. METHODS All patients with chronic lower limb ischemia who underwent isolated subintimal angioplasty of the infragenicular vessels between March 1997 and May 2000 were identified from the vascular audit database and angiography records. Patient records were scrutinized to gather data concerning patient demographics, presentation, angiographic findings, outcome of angioplasty, and longterm follow-up. The length of the arterial occlusion was determined from angiograms taken at the time of the procedure. Sixty-seven patients (39 men; mean age 76 years, range 41 96) with ischemia affecting 70 limbs were identified. Six (9%) patients had severe claudication, 21 (31%) suffered rest pain, 34 (51%) presented with ulceration, and 6 (9%) had gangrene. Thirty-nine (58%) were current or ex-smokers. Coexisting medical conditions included hypertension (54%), ischemic heart disease (49%), diabetes mellitus (46%), and cerebrovascular disease (15%). In addition to 2 patients with bilateral disease, 1 patient underwent repeat angioplasty after 14 months. All patients had a duplex scan of their lower limb vasculature prior to angioplasty; isolated atherosclerotic occlusion of below-knee popliteal, tibioperoneal trunk, or crural vessels was detected in all patients, but none of the study cohort had significant disease in the iliac or superficial femoral arteries (SFA). (Patients who had long SFA occlusions going into the infragenicular segments were excluded from the study.) No patients in the cohort fulfilled the clinical or radiological criteria for Buerger s disease. 4,12 The median length of occlusion was 6cm(range 1 10) in the below-knee popliteal arteries, 4cm(range 1 4) in the tibioperoneal trunk, 21 c m(range 1 35) in the anterior tibial artery, 10 (1 30) in the posterior tibial artery, and 5 (range 1 20) in the peroneal artery. Figure 1Angiogram showing an occlusion (between arrows) of the anterior tibial artery, tibioperoneal trunk, and peroneal artery before (A) and after (B) subintimal angioplasty. The point of reentry (distal arrow in B) in the anterior tibial artery is almost 25 cm from the origin of the occlusion. Subintimal Angioplasty The subintimal technique was identical to that described in previous publications. 8 11,14 16 The pattern of wire loop advancement in occluded vessels and re-entry in the lumen further down the vessel confirmed the subintimal technique (Figs. 1 and 2). The pretreatment aim was to restore antegrade flow in at least 1 crural artery. Occasionally, with favorable procedural criteria, several vessels were recanalized. All
SUBINTIMAL ANGIOPLASTY 413 Technical success was defined as satisfactory recanalization of at least 1 crural vessel, with antegrade flow into the pedal arch at the end of the procedure. Clinical success referred to resolution of claudication or rest pain and healing of ulcers with no or only minor amputations at 6 weeks. In our center, patients with successful angioplasty do not undergo routine vascular laboratory studies during follow-up. Postintervention ankle pressures or duplex scans were therefore not available. All patients, their relatives, or their general practitioners were contacted in November 2000 and were questioned about symptom recurrence. Limb salvage, freedom from critical limb ischemia (CLI), and survival rates were calculated by means of Kaplan Meier life-table analysis. 13 Figure 2Angiogram showing the occlusion (upper arrows) of the popliteal artery just below the knee before (A) and after (B) subintimal angioplasty. Lower arrows mark the points of re-entry in the peroneal and posterior tibial arteries. patients who could tolerate aspirin were sent home on this medication (75 mg). Definitions and Statistical Analysis RESULTS Angioplasty was successful in a single vessel in 20 limbs (29%), in 2 vessels in 15 limbs (21%), and in 3 vessels in 25 limbs (36%), for a technical success rate of 86%. Of the 5 (7%) intraprocedural perforations, 2 were self-limiting and 3 were coil embolized. In the postangioplasty period, there were 4 (6%) groin hematomas, which were managed conservatively. All 10 patients who had a technical failure demonstrated no clinical improvement (Fig. 3). Two patients developed acute limb ischemia as a complication of the procedure. One underwent successful bypass and the other had a major lower limb amputation. Of the remaining 8 patients, 2 underwent successful bypass, 3 had an amputation, 1 had a lumbar sympathectomy, and 2 were treated conservatively. In addition, 4 (6%) limbs that underwent subintimal angioplasty with a good radiological result did not achieve clinical success. Two patients required femorodistal bypass and their ulcers improved; in the other 2, they failed to heal completely. Total clinical success was 80%. No patients were lost to follow-up, but 26 died during the observation period (1 within 30 days of the procedure from multiple organ failure). At 3 years, 49% of patients were alive (Fig. 4). Life-table analysis also revealed that limb salvage was 94% at 6 months and remained at that level for 3 years. At 6 months, 84% had freedom from severe limb ischemia, which was sustained until the end of the study. Of the 31 (46%) diabetics in the study, 2 were diet controlled, 14 were treated with oral hypoglycemic agents, and 15 were insulin dependent. In this diabetic group, there were 4 technical failures that resulted in 1 bypass, 2 amputations, and 1 lumbar sympathectomy. There were also 2 clinical failures, which gave a clinical success rate in diabetics of 81%. Nei-
414 SUBINTIMAL ANGIOPLASTY Figure 3Schematic illustrating the results of crural subintimal angioplasty in 67 patients with chronic lower limb ischemia. ther technical nor clinical success rates differed in diabetic patients when compared to nondiabetics. In patients without diabetes, survival at the end of 3 years was 49% compared to 51% in diabetics (Fig. 5, p0.79). The rate of CLI (Fig. 6) was significantly lower in nondiabetics (4%) than in diabetics (24%, p0.02). This higher CLI rate did not convert into a significantly higher amputation rate, however (4% in nondiabetics versus 10% in diabetics, p0.26) (Fig. 7). DISCUSSION Figure 4Kaplan-Meier life-table analysis demonstrating survival, cumulative limb salvage, and cumulative freedom from severe limb ischemia at 12, 24, and 36 months in the 67-patient cohort. Until recently, patients with infragenicular arterial disease were treated conservatively or with popliteal-pedal bypass surgery. However, Biancari et al. 5 showed that although the 1-month patency rate after bypass surgery for CLI was 87%, it dropped to 55% after 2 years. Nicoloff et al. 17 also reported that only 14% of their patients who had limb salvage surgery achieved the ideal result of an uncomplicated operation with long-term symptom relief, preservation of functional status, and no recurrence or repeat surgery. Dotter and Judkin 18 first attempted percutaneous transluminal angioplasty (PTA) of crural vessels in 1964. More reports followed, 19,20 but most of these procedures were performed in association with SFA dilation; isolated PTA of
SUBINTIMAL ANGIOPLASTY 415 Figure 5Kaplan-Meier life-table analysis demonstrating the cumulative survival of diabetic versus nondiabetic patients (p0.79). Figure 6Kaplan-Meier life-table analysis demonstrating the cumulative freedom from critical limb ischemia (CLI) in diabetic versus nondiabetic patients (p0.02). Figure 7Kaplan-Meier life-table analysis demonstrating the cumulative limb salvage in diabetic versus nondiabetic patients (p0.26). crural arteries was rare. Schwarten et al. 7 reported an 86% limb salvage rate 2 years following below-knee PTA, but because of the small caliber of crural vessels and their tendency to develop spasm, PTA was mainly recommended for limb salvage. 6 The technique of subintimal angioplasty, which was first described by Bolia et al. 8 in SFA occlusions, has since been studied by several authors in other lower limb vessels. 10,11,14 A technical success rate of 74% to 81% has been reported for occlusions 10 cm in length. In this procedure, the subintimal plane is the path of least resistance; as the occlusion is traversed in an extraluminal plane, the lumen is not restricted by the original diameter of the artery. 21 Endovascular ultrasonography has shown that the compressed lumen is situated eccentrically, and the new lumen is wider than before. 15 In the present study of infragenicular arterial disease, 91% of patients had rest pain, ulceration, or gangrene. While no other reports of subintimal angioplasty on isolated crural vessels are available for comparison, our limb salvage rate and freedom from severe limb ischemia were 94% and 83%, respectively, at the end of 1 year and remained the same at 3 years. This compares favorably to poplitealpedal bypass, where limb salvage rates of 97%, 88%, and 88% for 1 month, 1 year, and 2 years have been described. 5 In spite of the distal nature of the angioplasty, only 2 (3%) patients developed acute ischemia as a complication of the procedure; 1 underwent successful bypass, but the other limb could not be salvaged. In the other 8 failed cases, there was no symptomatic deterioration. Four of these patients underwent successful bypass, which reaffirms the observation made by one of us (P.R.B.) that technical failure of subintimal angioplasty does not preclude conventional surgery. 22 Our rate of amputations among failed cases also is in agreement with the literature of infrapopliteal PTA; Bakal et al. 23 reported that almost half of their unsuccessful angioplasty cases underwent major amputation. Diabetics have a propensity for microvascular disease, and the presence of diabetes mellitus is an adverse prognostic factor in pa-
416 SUBINTIMAL ANGIOPLASTY tients suffering with peripheral vascular disease. 24 More than 50% of lower extremity amputations occur in patients with diabetes. 25 In our study, the difference in mortality was not significant, but the rate of CLI was much higher in diabetics than nondiabetics. Nevertheless, the rate of amputation was not significantly different between diabetics and nondiabetics. The current study has demonstrated that subintimal angioplasty may be effectively used as a first line treatment for patients with severe lower limb ischemia and distal vessel occlusion in centers with extensive experience of the technique. However, further studies will be required to determine the patency of the technique in other centers before widespread application can be recommended. REFERENCES 1. Haimovici H. Patterns of arteriosclerotic lesions of the lower extremity. Arch Surg. 1967;95:918 933. 2. Tordoir JH, van der Plas JP, Jacobs MJ, et al. Factors determining the outcome of crural and pedal revascularisation for critical limb ischaemia. Eur J Vasc Surg. 1993;7:82 86. 3. Arora S, LoGerfo FW. Lower extremity macrovascular disease in diabetes. J Am Podiatr Med Assoc. 1997;87:327 331. 4. Shionoya S. Diagnostic criteria of Buerger s disease. Int J Cardiol. 1998;66(suppl):S243 247. 5. Biancari F, Kantonen I, Alback A, et al. Poplitealto-distal bypass grafts for critical leg ischaemia. J Cardiovasc Surg (Torino). 2000;41:281 286. 6. Zeitler E, Schoop W, Zahnow W. The treatment of occlusive arterial disease by transluminal catheter angioplasty. Radiology. 1971;99:19 26. 7. Schwarten DE, Cutcliff WB. Arterial occlusive disease below the knee: treatment with percutaneous transluminal angioplasty performed with low-profile catheters and steerable guide wires. Radiology. 1988;169:71 74. 8. Bolia A, Miles KA, Brennan J, et al. Percutaneous transluminal angioplasty of occlusions of the femoral and popliteal arteries by subintimal dissection. Cardiovasc Intervent Radiol. 1990;13:357 363. 9. Nydahl S, Hartshorne T, Bell PR, et al. Subintimal angioplasty of infrapopliteal occlusions in critically ischaemic limbs. Eur J Vasc Endovasc Surg. 1997;14:212 216. 10. Vraux H, Hammer F, Verhelst R, et al. Subintimal angioplasty of tibial vessel occlusions in the treatment of critical limb ischaemia: midterm results. Eur J Vasc Endovasc Surg. 2000; 20:441 446. 11. Reekers JA, Bolia A. Percutaneous intentional extraluminal (subintimal) recanalization: how to do it yourself. Eur J Radiol. 1998;28:192 198. 12. Suzuki S, Yamada I, Himeno Y. Angiographic findings in Buerger disease. Int J Cardiol. 1996; 54(suppl):S189 195. 13. Andersen PK. Survival analysis 1982 1991: the second decade of the proportional hazards regression model. Stat Med. 1991;10:1931 1941. 14. McCarthy RN, Neery W, Roobottom C, et al. Short-term results of femoropopliteal subintimal angioplasty. Br J Surg. 2000:87:1361 1365. 15. London NJ, Srinivasan R, Naylor AR, et al. Subintimal angioplasty of femoropopliteal artery occlusions: the long-term results. Eur J Vasc Surg. 1994;8:148 155. 16. Reekers JA, Kromhout JG, Jacobs MJ. Percutaneous intentional extraluminal recanalisation of the femoropopliteal artery. Eur J Vasc Surg. 1994;8:723 728. 17. Nicoloff AD, Taylor LMJ, McLafferty RB, et al. Patient recovery after infrainguinal bypass grafting for limb salvage. J Vasc Surg. 1998;27: 256 266. 18. Dotter CT, Judkins MP. Transluminal treatment of arteriosclerotic obstruction. Circulation. 1964;30:654 656. 19. Dorros G, Lewin RF, Jamnadas P, et al. Belowthe-knee angioplasty: tibioperoneal vessels, the acute outcome. Cathet Cardiovasc Diagn. 1990;19:170 178. 20. Isner JM, Rosenfield K. Redefining the treatment of peripheral artery disease. Role of percutaneous revascularization. Circulation. 1993; 88(Pt 1):1534 1557. 21. Moore WS, Ahn SS. Techniques of percutaneous balloon angioplasty including aortoiliac and femoropopliteal systems: indications, results and complications. In: Moore WS, Ahn SS, eds. Endovascular Surgery, Philadelphia: WB Saunders; 1989:163 208. 22. Bell PR. The clinical impact of the Pier technique. Eur J Radiol. 1998;28:189 191. 23. Bakal CW, Cynamon J, Sprayregen S. Infrapopliteal percutaneous transluminal angioplasty: what we know. Radiology. 1996;200:36 43. 24. McDaniel MD, Cronenwett JL. Basic data related to the natural history of intermittent claudication. Ann Vasc Surg. 1989;3:273 277. 25. Spollett GR. Preventing amputations in the diabetic population. Nurs Clin North Am. 1998; 33:629 641.