The only randomized clinical trial comparing open bypass to endovascular interventions for CLI is the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial [9, 11, 14]. This was a prospective multicenter study sponsored by United Kingdom National Institute of Health Research Technology Assessment Program and included patients with severe limb ischemia which is a less stringent definition of ischemia that does not include ankle or toe pressure thresholds. To be enrolled in BASIL, patients had to be suitable for either open surgery or endovascular intervention and were randomized to a bypass surgery first or balloon angioplasty first strategy. Primary endpoints were amputation free survival (AFS), overall survival, heath-related QOL, and cost-effective use of hospital resources. In the initial year, surgery was associated with lower rate of early failure and reintervention, while having similar perioperative mortality, and higher perioperative morbidity [11]. Initial analysis of this trial showed that there was no significant difference in AFS at 1 and 3 years (68 % and 57 % for surgery and 71 % and 52 % for angioplasty first) [11]. Surgery was associated with significantly more morbidity and perioperative complications (57 % vs. 41 %, difference 15.5 %, 95 % CI 5.8–24.8). Most of these events were infections, wound complications, and cardiovascular events. Post-hoc survival curve analysis showed a reduced hazard in amputation-free survival (HR 0.37, 95 % CI 0.17–0.77, p = 0.008) and all-cause mortality (0.34, 95 % CI 0.17–0.71, p = 0.004) for surgery compared to angioplasty among patients who survived more than 2 years [11].

Long term follow up revealed that the surgery first strategy was associated with a lower hazard for amputation free survival (HR 0.85; 95 % CI 0.50–1.07; p = 0.108) and improved overall survival (HR 0.61; 95 % CI 0.50–0.75; p = 0.009) [14]. Furthermore, patients who underwent bypass surgery after an initial failed angioplasty had significantly worse outcomes than those who underwent bypass as the initial therapy, highlighting the potential negative implications of an endovascular-first approach. Surgical patients treated with vein bypass had significantly higher amputation free survival compared to those treated with prosthetic grafts [14, 15]. Soga et al. performed a retrospective review of CLI patients over a 6 year period at 14 centers in Japan [12]. These authors compared initial treatment using bypass versus endovascular therapy. Amputation free survival, limb salvage, overall survival and major adverse cardiac events were not different between the two groups, overall and when adjusted for covariates. Freedom from major adverse limb events (HR, 0.66; 95 % CI: 0.47–0.92, P = 0.01) and major adverse cardiovascular and limb events (HR, 0.75; 95 % CI: 0.58–0.97, P = 0.02) were lower in the endovascular therapy group. Trans-Atlantic Intersociety Consensus (TASC) II classification, lesion length and percent stenosis were all recorded in this study. However multivariate analysis was based on comorbidities alone and did not include anatomical characteristics. Bypass was used to treat significantly more TASC II D lesions as well as longer, more stenotic, and more chronic total occlusions than endovascular therapy, thus potentially skewing results.

Dosluoglu et al. performed a retrospective single center analysis of patients undergoing infrainguinal revascularization for CLI to assess patient characteristics and outcomes. Patients in the endovascular group were older, had more diabetes, tissue loss, and renal insufficiency. The open group had a higher level of infrapopliteal revascularization. The 30 day mortality was higher in the open group (6 % vs. 2.8 %), however this did not reach statistical significance (P = .079). There was no difference in AFS, overall survival, or primary patency. Secondary patency and primary assisted patency were higher with endovascular interventions. However, in this study the endovascular patients had less extensive disease therefore a side by side comparison cannot be accurately assessed. The open group had 99 % TASC II D lesions and the endovascular group has 52 % TASC II D lesions. TASC II classification was not adjusted for in multivariate analysis.

Korhonen and colleagues performed a single center retrospective study comparing AFS between endovascular interventions and bypass [17]. Patients undergoing endovascular therapy had lower AFS (42 % vs. 53.7 %, p = .003) and freedom from surgical re-intervention (86.2 % and 94.3 %, P</001). Propensity score analysis showed that leg salvage and freedom from surgical re-intervention were worse after endovascular therapy than after bypass (among the 241 propensity score-matched pairs, 74.3 % vs. 88.2 %, p = 0.031, and 86.1 % vs. 89.8 %, p = 0.025, respectively). Differences in survival, AFS and freedom from any re-intervention were not observed. The same group then published their data in octogenarians. The propensity match scored two cohorts based on comorbidities, indications, and vessel involvement for patient greater than 80 years old with CLI [16]. The endovascular cohort at 2 years had a higher AFS (53 % vs. 44.9 %, P = .005) and bypass surgery was an independent factor in decreased AFS (RR 1.55, 95 % CI 1.24–1.93). However propensity scoring did not take into account the extent of disease, occlusive vs. stenotic lesions, lesion length, and TASC II making direct comparison difficult.

Healthcare QOL was assessed using the Vascular Quality of Life Questionnaire (VascuQol) that specifically assesses pain, symptoms, activities, social, and emotional wellbeing. The generic Short Form 36 (SF-36) health survey and utility scores from the EuroQoL 5-D (EQ-5D) were also used. The BASIL trial did not find significant differences in the QOL between the two treatment strategies [9]. The methodology of the BASIL trial has been criticized on numerous fronts [16]. First, the trial limited allowable procedures in their endovascular cohort to angioplasty alone, which does not represent current management strategy. Exclusion of tools in the armamentarium of the endovascular specialist, such as stents, both biases the trial results and severely limits their generalizability. Second, AFS is significantly flawed as a primary endpoint to compare revascularization strategies as it both overemphasizes non-treatment-related mortality and underemphasizes limb-related events specifically attributable to treatment modality. Third, the study did not address the influence of anatomic patterns of disease on outcome. Fourth, the trial did not include any assessment of the hemodynamic success or failure of the treatment arms, a significant omission given the importance of objectively measuring treatment-related changes in perfusion in patients with CLI [9, 11, 14, 15].

Vogel and colleagues looked at changes in functional status in elderly patients treated with bypass and endovascular interventions by linking Medicare inpatient claims with nursing home assessment data [10]. A functional impairment score, based on need for assistance with activities of daily living, was calculated pre-procedurally, post-procedurally and at 6 months. Both patient groups demonstrated a decrease in their functional status, corresponding to the severity of their disease, in the immediate post-operative period. The less invasive endovascular procedure did not result in less impairment of functional status. Other factors that impaired long-term functional status post-procedure were female gender and poor baseline cognitive and functional ability. Recovery rates at 6 months were higher in the bypass than in the endovascular group. This is an analysis comparing large administrative databases and has limitations. Although the pre-operative functional status was similar, the severity of disease and details of the reconstruction were unclear. Furthermore, patients who were readmitted and those who had concurrent amputations were excluded.

When looking at QOL broken down into different categories, a retrospective survey sent out to patients after open and endovascular interventions revealed no difference between endovascular and open surgery post-procedure in patients [4]. However, compared to age and gender matched cohorts, patients undergoing open vascular surgery overall scored considerably lower for every variable. The largest differences seen in mobility, breathing, sleeping, discomfort, vitality, and sexual activity. Surgical patients were also less likely to have social support, more likely to have walking limitations, worse Geriatric Depression and Life Satisfaction scores, and a poorer perception of health.