Endovascular-First Strategy in Patients with Critical Limb Ischemia

Introduction

Surgical bypass is considered the gold standard for the treatment of patients with chronic severe lower extremity ischemia.^1,2 However, the 5-year limb salvage rates reported as high as 80% in single center/surgeon series have not been reproduced in multicenter studies or national registries.^1,3,4 Often, these are extensive surgeries being performed in a mostly elderly patient population with multiple comorbidities. This has an impact on functional outcome. Only 45% of patients under going infrainguinal bypass reported feeling “back to normal” at 6 months.⁵ Recent advances in endovascular technology, coupled with the perception of associated lower morbidity and mortality has made the percutaneous treatment of severe lower extremity ischemia more attractive in recent years. At our institution we adopted an “endovascular-first” strategy in the management of patients with chronic severe lower extremity ischemia regardless of their age or comorbidities. The goal of this study was to evaluate the treatment outcomes of this approach in all patients presenting to our institution with chronic severe lower extremity ischemia.

Materials and Methods

The study is a retrospective analysis of 29 consecutive patients with infrainguinal occlusive disease manifesting as severe chronic ischemia (33 limbs) who were treated with a combination of endovascular techniques over 26 months (October 2003 to December 2005). The decision to treat using endovascular techniques was based upon clinical examination, diagnostic imaging and at the discretion of the interventionalist. Patients who had treatment of isolated suprainguinal lesions were excluded. Also excluded were patients presenting with acute ischemia or a functionally useless limb.

Endovascular Techniques

All procedures were performed in a dedicated interventional suite or a hybrid endovascular operating room. Diagnostic imaging was performed either prior to the procedure using gadolinium-enhanced magnetic resonance angiography or at the same time as the intervention using iodinated contrast. TransAtlantic Inter-Society Consensus (TASC) classification was used to categorize the limbs’ morphologic arterial lesions. Either an antegrade or retrograde common femoral approach was used for arterial access. Heparin anticoagulation was used to obtain an activated clotting time of > 200 seconds throughout the procedure. Superficial femoral artery lesions were crossed using an angled 0.035 hydrophilic wires. Popliteal and infrapopliteal lesions were crossed using 0.014 hydrophilic wires. Superficial femoral artery lesions underwent angioplasty and primary stenting with either Smart Stents (Cordis, Warren, New Jersey) or Viabahn stent grafts (WL Gore & Assoc. Flagstaff, Arizona). Popliteal and infrapopliteal lesions underwent either balloon angioplasty, Clirpath Excimer laser angioplasty (Spectranetics, Colorado Springs, Colorado) or SilverHawk atherectomy (Foxhollow, Redwood, California) or a combination of the above. Intraprocedural angiographic data were recorded for later analysis. Post-procedure all patients were treated with 300mg clopidogrel if not previously prescribed, and maintained on 75 mg/day for a minimum of 6 weeks.

Follow-up

Follow-up consisted of gradation of symptoms, physical examination and non-invasive measurements including ankle brachial indices and pulse volume recordings. Patients were seen within one month of the procedure, then every 6 months thereafter.

Definitions

Technical success was defined as the ability to obtain in-line arterial flow into the foot with less than a 20% residual stenosis using percutaneous techniques. Clinical success was defined as the resolution of rest pain or healing of an ulcer or amputation site. Limb salvage was defined as the ability to avoid major level amputation (below or above knee).

Statistics

Data were entered into an Excel spreadsheet (Microsoft, Inc, Redmond, Washington). Data were transferred into SPSS software (SPSS, Inc, Chicago, Illinois) for statistical analysis.

Results

Thirty three limbs in 29 male patients were treated over a period of 25 months. The mean age was 67.1 years (range, 48–82 years). All patients were male. Patient demographics and clinical presentation are summarized in Tables 1 and 2. The mean length of follow-up was 11.4 months (range, 2–23 months). Indications for intervention included claudication (Fontaine II) in 2 limbs, rest pain (Fontaine III) in 10 limbs, and digital ulceration or gangrene (Fontaine IV) in 21 limbs. The patients’ lesions were categorized by TASC classification: A, n = 10; B, n = 1; C, n = 5; D, n = 15. Of the interventions, twenty were isolated to the superficial femoral artery and thirteen were multilevel (Table 3). Technical success as defined by the ability to obtain in-line arterial flow into the foot with less than a 20% residual stenosis was achieved in 31 limbs (93%). Of the two technical failures, one of the procedures was prematurely aborted due to acute respiratory failure secondary to oversedation. Because of the patients’ poor overall medical condition, a further attempt at revascularization was not attempted. The other technical failure was due to the inability to completely cross the lesion with a wire. Intra-procedural complications included clinically significant embolization (n = 2, successfully treated by intraprocedural thrombolysis) and acute respiratory failure (n = 1). Post-procedure complications included puncture site pseudoaneurysm necessitating operative repair (n = 1), and self-limiting acute renal failure (n = 1). Two patients (6.9%) died within 30 days post procedure of cardiac-related events. Target lesion reintervention was necessary in 4 limbs (12.9%) at an average of 4.25 months from initial treatment. Three of these patients had in-stent restenosis, and one had in-stent thrombosis, all of which were treated using endovascular techniques. Over the course of the study, 5 patients (17%) died. Of those patients who had a technically successful procedure, 5 underwent a major level amputation during the follow-up period. The limb salvage rate was 83.9%. Clinical success as defined by the resolution of rest pain or healing of an ulcer or amputation site was documented in 83.9%. In patients who had a technically successful intervention and then went on to have limb loss, the mean time to amputation was 7.2 months. The presence of infrapopliteal disease correlated with a higher rate of limb loss than suprapopliteal disease (p Conclusions Lower extremity bypass grafting is the traditional first choice modality of therapy for patients with presenting CLI. However, infrainguinal bypass surgery is often associated with high periprocedural morbidity, prolonged recovery, and multiple reoperations.^6,7 Percutaneous interventions for CLI have therefore been typically reserved for patients with comorbid conditions at increased surgical risk. Several groups have demonstrated that an “endovascular-first” approach can produce comparable limb salvage rates to surgery.^8,9 This has been demonstrated in the BASIL trial.¹⁰ The “endovascular-first” approach has advantages of being associated with lower morbidity and mortality, shorter hospitalization times and can be repeated. Furthermore, endovascular procedures do not compromise the potential for subsequent surgical revascularization. The LACI investigators achieved good limb salvage rates with the use of laser-assisted angioplasty in their registry.¹¹ However, we found poorer results with use of this modality for revascularization. This may be due to the confounding factor of the predominant use of laser for infrapopliteal disease in our group. An interesting paradoxical observation in this study was that no statistical difference in limb salvage rates based upon clinical presentation or TASC classification, but the presence of infrapopliteal disease did correlate with a higher rate of limb loss. In conclusion, our results add support that an “endovascular-first” strategy can yield good limb salvage rates in patients with advanced lower extremity limb ischemia regardless of their associated comorbidities.