Cardiac adaptation to obesity and hypertension after heart transplantation.

Obesity and hypertension frequently develop after heart transplantation. The cardiac adaptation to obesity and hypertension was studied by determining hemodynamic and echocardiographic indexes in 10 obese hypertensive patients (body mass index greater than or equal to 27.8 kg/m2 in men or greater than or equal to 27.3 kg/m2 in women) matched by mean arterial pressure, age and gender with 10 nonobese hypertensive patients 1 year after cardiac transplantation. Cardiac output was 30% greater (p less than 0.02) and systemic vascular resistance 25% lower (p less than 0.01) in the obese than in the nonobese patients. Right ventricular systolic and pulmonary artery systolic, diastolic and mean pressures were also significantly higher (p less than 0.05) in the obese patients. Left ventricular end-diastolic diameter was 25% greater (p less than 0.05), left ventricular mass 28% greater (p less than 0.02) and left ventricular end-diastolic volume 20% higher (p less than 0.01) in the obese subjects. Left ventricular ejection fraction was significantly lower in the obese than in the nonobese subjects (34% vs. 51%, p less than 0.05). These results indicate that the cardiac adaptation to obesity and hypertension after heart transplantation consists of left ventricular dilation and an increase in left ventricular mass associated with an increased cardiac output and lower peripheral vascular resistance. These adaptive changes that occur in obese hypertensive patients after heart transplantation might increase the long-term risk of graft failure, as suggested by their lower left ventricular ejection fraction 1 year after transplantation.