Impact of obesity on long-term survival after aortic valve replacement with a small prosthesis

Abstract

Although many studies have evaluated the impact of obesity on various medical treatments, it is not known whether obesity is related to late mortality with implantation of small aortic prostheses. This study evaluated the effect of obesity on the late survival of patients after aortic valve replacement (AVR) with implantation of a small aortic prosthesis (size ≤ 21 mm). From January 1998 to December 2008, 307 patients in our institution who underwent primary AVR with smaller prostheses survived 30 days after surgery. Patients were categorized as normal weight if body mass index (BMI) was <24 kg/m(2), overweight if BMI 24-27.9 kg/m(2) and obese if BMI ≥ 28 kg/m(2). Data of the New York Heart Association (NYHA) functional classification, left ventricular ejection fraction (LVEF), effective orifice area index (EOAI) and left ventricular mass index of the patients were collected at the third month, sixth month, first year, third year, fifth year and eighth year after operation. By multivariable analysis, obesity was a significant independent factor of late mortality (hazard ratio: 1.62; P = 0.01). The obese and overweight groups of patients exhibited lower survival (P < 0.001) and a higher proportion in NYHA Class III/IV (P < 0.01) compared with the normal group. A lower EOAI and higher left ventricular mass index were found in the obese and overweight groups, but we saw no significant variance in LVEF among the three groups. Obesity is associated with increased late mortality of patients after AVR with implantation of small aortic prosthesis. Obesity or/and overweight may also affect the NYHA classification, even in the longer term. EOAI should be improved where possible, as it may reduce late mortality and improve quality of life in obese or overweight patients.