Impact of Bypass Flow Assessment on Long-Term Outcomes in Patients with Chronic Limb-Threatening Ischemia

Area of Science:

• Vascular Surgery
• Medical Devices
• Clinical Outcomes Research

Background:

• Chronic limb-threatening ischemia (CLTI) necessitates complex surgical interventions.
• Below-the-knee (BTK) vein bypass surgery is a critical treatment for CLTI.
• Intraoperative graft assessment is vital for long-term success.

Purpose of the Study:

• To evaluate the impact of graft flow measurements on long-term clinical outcomes.
• To determine the prognostic value of transit time flow meter (TTFM) parameters in BTK vein bypass surgery for CLTI patients.
• To identify specific TTFM thresholds associated with adverse outcomes.

Main Methods:

• Retrospective analysis of 249 CLTI patients undergoing BTK vein bypass surgery.
• Graft flow assessed using TTFM at the end of the procedure.
• Patients categorized into four groups based on mean (<100 ml/min) and diastolic (<40 ml/min) graft flow.
• Primary endpoints: major adverse limb event (MALE) and primary graft patency.

Main Results:

• A subgroup with mean graft flow <100 ml/min and diastolic graft flow <40 ml/min exhibited the highest MALE rates.
• The same subgroup demonstrated the poorest primary graft patency.
• Statistical significance was confirmed for both MALE and graft patency outcomes (P < 0.01).

Conclusions:

• TTFM-derived graft flow parameters are significant predictors of long-term outcomes in CLTI patients undergoing BTK bypass.
• Mean graft flow <100 ml/min combined with diastolic graft flow <40 ml/min indicates a high risk for poor graft function and limb events.
• These findings underscore the importance of intraoperative TTFM assessment for optimizing surgical strategy and patient management.