BASIL-3 Trial Overview
The BASIL-3 trial does not exist in the provided evidence; however, the BASIL-2 trial (2023) represents the most recent and highest-quality evidence, demonstrating that a best endovascular treatment first strategy results in superior amputation-free survival compared to vein bypass first for patients with chronic limb-threatening ischemia requiring infra-popliteal revascularization. 1
Key Findings from BASIL-2 (2023)
The BASIL-2 trial fundamentally challenges earlier recommendations based on the original BASIL trial from 2005-2011:
Best endovascular treatment first was associated with better amputation-free survival (adjusted HR 1.35 for vein bypass, 95% CI 1.02-1.80; p=0.037), meaning vein bypass first had 35% higher risk of amputation or death 1
The survival benefit was driven primarily by lower mortality in the best endovascular treatment group (53% died in vein bypass group vs 45% in endovascular group; adjusted HR 1.37,95% CI 1.00-1.87) 1
Cardiovascular and respiratory events were the most common causes of death in both groups, occurring within 30 days of first revascularization and throughout follow-up 1
Treatment Algorithm Based on Current Evidence
For Chronic Limb-Threatening Ischemia Requiring Infra-Popliteal Revascularization:
First-Line Strategy:
- Initiate with best endovascular treatment (plain balloon angioplasty with selective use of plain or drug-eluting stents) for patients requiring infra-popliteal ± additional proximal infra-inguinal revascularization 1
Historical Context: Original BASIL Trial (2005-2011)
The earlier BASIL trial findings, which informed 2011 ACC/AHA guidelines, showed different results:
No overall difference in amputation-free survival or overall survival between bypass-first and angioplasty-first strategies at 2.5 years 2
For patients surviving ≥2 years, bypass surgery-first was associated with 7.3 months increased overall survival (95% CI 1.2-13.4 months; p=0.02) and trend toward 5.9 months improved amputation-free survival (95% CI -0.2 to 12.0 months; p=0.06) 2
Bypass surgery-first was one-third more expensive and associated with higher initial morbidity than angioplasty-first 2
Critical Differences Between BASIL and BASIL-2
The BASIL-2 trial contradicts the original BASIL findings, representing a paradigm shift:
BASIL-2 specifically focused on infra-popliteal disease (below-knee), whereas original BASIL included infrainguinal disease more broadly 1
BASIL-2 used "best endovascular treatment" (including drug-eluting technology when appropriate), not just plain balloon angioplasty 1
BASIL-2 enrolled patients between 2014-2020, reflecting modern endovascular techniques and perioperative care 1
The mortality difference favoring endovascular treatment in BASIL-2 suggests that the surgical stress of bypass may be particularly detrimental in this high-risk population 1
2011 ACC/AHA Guideline Recommendations (Now Outdated)
These recommendations were based on the original BASIL trial and should be reconsidered in light of BASIL-2:
For life expectancy ≤2 years or no autogenous vein available: Balloon angioplasty is reasonable as initial procedure (Level of Evidence B) 2
For life expectancy >2 years with autogenous vein available: Bypass surgery is reasonable as initial treatment (Level of Evidence B) 2
Clinical Implications and Caveats
Important considerations when applying BASIL-2 findings:
The survival benefit in BASIL-2's endovascular group challenges the life expectancy-based algorithm from 2011 guidelines, suggesting endovascular-first may be preferable regardless of predicted survival 1
Prosthetic bypass grafts performed poorly in the original BASIL trial, with outcomes worse than vein bypass 2, 3
Failed endovascular interventions followed by bypass surgery had worse outcomes than primary bypass in original BASIL, suggesting the importance of appropriate initial treatment selection 3
Most vein bypasses in BASIL-2 originated from common or superficial femoral arteries using great saphenous vein 1
Most endovascular interventions comprised plain balloon angioplasty with selective stenting 1
Common Pitfalls to Avoid
Do not delay endovascular treatment in favor of bypass based solely on life expectancy >2 years, as BASIL-2 shows superior outcomes with endovascular-first approach 1
Do not use prosthetic conduits when vein is unavailable without considering endovascular options first, given poor prosthetic bypass outcomes 2, 3
Do not perform bypass after failed endovascular intervention without recognizing this carries worse prognosis than primary bypass 3
Recognize that cardiovascular and respiratory complications drive mortality in both treatment groups, emphasizing need for medical optimization 1