Impact of Body Mass Index on the Initial Phase of a Minimally Invasive Aortic Valve Program.

Background:  In obese patients, minimally invasive surgical 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:  A total of 307 patients underwent MIS-AVR between January 2013 and December 2015, the initial phase of our MIS-AVR program. They were divided into normal/overweight (BMI <30 kg/m²) versus obese patients (BMI ≥30 kg/m²). Primary endpoints included 30-day and 2-year mortality and stroke. Secondary endpoints comprised type 3 bleeding, PPM, paravalvular leakage, wound healing disorders (WHDs), and pacemaker rates.

Results:  In all 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 ± 29 min vs. 87 ± 37 min; p = 0.001), cardiopulmonary bypass (104 ± 36 min vs. 124 ± 56 min; p = 0.0002), and ventilation times (26 ± 6 h vs. 44 ± 8 h; 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. No BMI-related differences revealed in 30-day mortality (4.7% vs. 3.4%) and stroke rates (2% vs. 2.6%), as well as 2-year mortality (12.6% vs. 11.2%) and stroke rates (2.1% vs. 2.6%).

Conclusion:  In the initial phase of an 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.