Underweight and obesity represent classical risk factors for adverse outcome in patients treated for cardiovascular disease.

The current analysis examines the impact of underweight, overweight and obesity on intra-hospital, short and long-term outcomes in patients treated by MitraClip therapy.

From August 2010 until July 2013, 799 patients (age 75.3 ± 8.6 years, male gender 60.7%, median logistic EuroSCORE 20% [12; 31], functional mitral regurgitation (MR): 69.3%) were prospectively enrolled into the multicenter German Transcatheter Mitral Valve Interventions registry. Patients were stratified according to body mass index (BMI) into 4 groups: BMI <20 kg/m² (underweight), BMI 20.0 to <25.0 kg/m² (normal weight, reference group), BMI 25.0 to <30.0 kg/m² (overweight) and BMI ≥30 kg/m² (obese).

Significant increased rates of procedural failure, transfusion/bleeding, sepsis or multiorgan failure and low cardiac output failure were found for underweight patients only. Kaplan–Meier survival curves demonstrated inferior survival for underweight patients, but comparable outcomes for all other patients (global log rank test, P < .01). Multivariable Cox-regression analysis (adjusted for age, gender, creatinine ≥1.5 mg/dL, diabetes, left ventricular ejection fraction <30% and chronic obstructive pulmonary disease) confirmed underweight (as compared to normal weight) as an independent risk factor of death (hazard ratio [HR]: 1.58, 95% confidence interval (CI): 1.01-2.46, P = .044) and overweight as protective against death (HR: 0.71; 95%-CI: 0.55–0.93; P = .011).

Compared to other weight groups, underweight patients undergoing MitraClip implantation are exposed to increased rates of procedural failure, bleeding and low cardiac output as well as increased short- and long-term mortality rates and should therefore be carefully discussed in the heart-team.