Comparison of long-term results of lower limb bypass grafts using autogenous vein and prosthetic grafts

Abstract

Purpose: Infra-inguinal revascularisation surgeries performed locally involve either an autogenous vein or a prosthetic graft as a conduit. Local follow-up of patients post-operatively includes surveillance ultrasound scans for patients with an autogenous bypass graft compared to a single ultrasound scan one week post-operatively for patients with a prosthetic graft. The literature indicated conflicting studies with regards to the effectiveness of ultrasound surveillance for prosthetic bypass grafts after infra-inguinal revascularisation.

Objectives: To compare patency rates and subsequent success rates of prosthetic bypass grafts when compared to autogenous vein grafts, of a cohort of patients who had undergone infrainguinal bypass surgery at a local general hospital in Malta. Another objective was to evaluate whether more regular follow-up ultrasound scans may be useful for patients undergoing revascularisation using a prosthetic bypass graft.

Methodology: The study adopted a quantitative, descriptive, non-experimental research design that involved the collection of retrospective and prospective data. The sampled population comprised of 120 patients (62 prosthetic and 58 autogenous) who had undergone infrainguinal bypass revascularisation between 2008 and 2018 at a general hospital in Malta. Patients with a prosthetic bypass graft were prospectively recruited for a duplex ultrasound scan, during which measurements were taken to determine graft patency at a given postoperative date. Retrospective data pertaining to a cohort of patients who had underwent ultrasound surveillance for autogenous bypass revascularisation was also collected. Attention was taken to ensure that both cohorts comprised of patients with similar characteristics, so as to allow better comparison of findings. A Kaplan-Meier curve was used to demonstrate patency rates in the two groups of subjects in the study.

Results: No significant differences were observed with respect to demographic data and risk factors between the two groups. Long-term patency results were found to be statistically significant (p = <0.001), with prosthetic grafts demonstrating overall patency rates of 40.3%, while that of autogenous grafts being 82.7%. Primary patency of prosthetic and autogenous grafts were 35.5% vs 53.4%, primary-assisted 37.1% vs 81.0% and secondary patency 40.3% vs 82.7% respectively, over a mean follow-up period of 1.7 years for prosthetic and 3.5 years for autogenous grafts. Major amputations were required in 17.7% of patients with a prosthetic graft compared to 0% of patients with an autogenous graft.

Conclusion: The findings from this small scale study indicate that autogenous bypass grafts had superior long-term patency results and therefore remain the conduit of choice for revascularisation procedures. Graft occlusion and limb loss was significantly greater in patients with a prosthetic graft. Further research is required to determine whether ultrasound surveillance scans in patients with prosthetic grafts would improve patency rates.