VENTRICULAR-ARTERIAL COUPLING IN CARDIAC TRANSPLANTATION: DETERMINING FACTORS AND PROGNOSTIC ROLE

Background: In transplanted heart patients, adaptation of the new heart to a different afterload to which it has been exposed in the donor’s body may bring some consequences on graft function. Usually, ejection fraction (EF) assesses graft performance and when its value is below normal ranges it is known to imply poor prognosis. Nevertheless, even in range of normality some patients have worse outcome than others. In this group of patients, we aimed to study ventricular arterial coupling (VAC) as another tool to assess prognosis because it reflects the interaction between the heart and the arterial system through the ratio arterial elastance (Ea), as an expression of arterial afterload, and end-systolic elastance (Ees) expressing left ventricle contractility. Aim: The goal is to create a statistical model using clinical, echocardiographic and VAC derived parameters to determine prognosis in heart transplanted (HT) patients. Methods: The study was conducted in HT patients with normal EF, no graft rejection, no cardiac allograft vasculopathy and had survived first year after surgery. Clinical, echocardiographic and pressure-volume derived parameters were gathered 1 year after transplantation and during a 30-year follow-up until death. VAC and other pressure-volume derived parameters were measured with a noninvasive method. Survival predictors were analyzed with univariate and multivariate Cox analyzes. Results: HT patients were coupled compared to controls but with higher Ea and Ees. Uncoupled hearts were mainly due to impaired contractility. Male patients and patients with higher end-systolic and end-diastolic volumes were associated with higher mortality, they were also proportionally associated with higher VAC values. Patients with VAC >0.59, Ea >4mmHg, Ees ≤6.75mmHg/ml had a worse long-term prognosis (p= 0.02). Ea and Ees also showed to be independent mortality prognostic factors (p= 0.02 and 0.001 respectively). Conclusions: VAC predicts long-term outcomes in transplanted heart patients only as a univariate variable, however, Ea and Ees when studied separately proved to be independent prognostic risk factors. These parameters are particularly useful since they can be easily determined with simple calculations and echocardiographic measurements that are routinely evaluated by cardiologists.