Impact of body mass index on an initial minimally invasive aortic valve program.

Background: In obese patients, minimally invasive aortic valve replacement (MIS-AVR) presents challenges, and the risk of patient-prosthesis mismatch (PPM) is elevated. This retrospective single-center study evaluates the impact of body mass index (BMI) on the outcome of an initial MIS-AVR program.

Material And Methods: 307 patients underwent MIS-AVR between 01/2013-12/2015, the initial phase of our MIS-AVR program. They were divided into normal/overweight (BMI<30 kg/m2) vs obese patients (BMI≥30 kg/m2). Primary endpoints included 30-day and two-year mortality and stroke. Secondary endpoints comprised type-3 bleeding, PPM, paravalvular leakage, wound healing disorders, and pacemaker rates.

Results: 191 patients exhibited a BMI<30 kg/m2, while 116 patients had a BMI≥30 kg/m2. The BMI-groups did not differ in baseline characteristics, excepting a higher peripheral arterial disease incidence among obese patients (15.7% vs 26.7%; p=0.01). Aortic clamp-time (75±29min vs 87±37min; p=0.001), cardiopulmonary bypass- (104±36min vs 124±56min; p=0.0002) and ventilation times (26±6h vs 44±8h; p=0.03) were longer in obese patients. They demonstrated a higher risk for bleeding (2.6% vs 9.5%; p=0.008) but lower pacemaker rates (9% vs. 3%; p=0.02). PPM, paravalvular leakage and WHD exhibited no group differences. 30-day mortality (4.7% vs. 3.4%) and stroke rates (2% vs. 2.6%), as well as two-year mortality (12.6% vs. 11.2%) and stroke rates (2.1% vs. 2.6%), revealed no BMI-related differences.

Conclusion: In the initial phase of a MIS-AVR program, the 30-day mortality may be elevated. Despite longer operative times and an increased risk for bleeding in obese patients, no influence of BMI on postoperative morbidity, mortality, or stroke rates was observed.