Impact of Preoperative Body Mass Index on Long-term Survival, Quality of Life, and Functional Outcomes after Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension: Results from the UK National Cohort.

Abstract

BACKGROUND Previous studies have demonstrated the safety of pulmonary endarterectomy (PEA) in all body mass index (BMI) strata. However, long-term survival and patient-reported quality of life outcome measures by BMI strata remain unknown. We sought to examine the impact of preoperative BMI on long-term survival, quality of life, and functional outcomes for patients undergoing PEA for chronic thromboembolic pulmonary hypertension (CTEPH). METHODS Retrospective review of 2004 patients from the UK National Cohort between 2007 and 2021 undergoing PEA for CTEPH (mPAP>20 mmHg and PVR>160 dynes). Patients were stratified into BMI<20, 20-29, 30-39, 40-49, and 50+. All-cause mortality was the primary outcome measure. Secondary outcome measures were 3-6 month postoperative hemodynamics, 6-minute walk distance (6MWD), New York Heart Association (NYHA) class, and Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR) scores. Kruskal-Wallis, ANOVA, and Kaplan Meier Estimate were used for comparisons. RESULTS Postoperative hemodynamics and 6MWD at 3-6 months were similar across BMI strata. However, patients with BMI 50+ reported the highest incidence of post-operative NYHA III/IV limitation (53.3%, p<0.001) and the highest residual symptom burden by CAMPHOR (p<0.001). Overall 5-year survival was lowest in patients with BMI 50+ (70.2%) and BMI<20 (73.4%), whilst highest in BMI 30-39 (88.2%, p=0.008). 10-year Kaplan-Meier Estimates predicted lowest survival in BMI 50+ and BMI<20. CONCLUSION PEA remains safe and effective for all patients regardless of BMI. Despite similar hemodynamic outcomes, patients with BMI 50+ are at greatest risk of long-term all-cause mortality and patients with BMI 50+ experience residual symptomatic limitation.