Can Echocardiographic Evaluation of Cardiopulmonary Hemodynamics Decrease Right Heart Catheterizations in End-Stage Heart Failure Patients Awaiting Transplantation?

Abstract

Candidacy for heart transplantation is influenced by the severity of pulmonary hypertension. In this study, invasive hemodynamics from right-sided cardiac catheterization were compared with values obtained by validated equations from Doppler 2-dimensional transthoracic echocardiography. This prospective study was conducted in 40 patients with end-stage heart failure evaluated for heart transplantation or ventricular assist device implantation. Transthoracic echocardiography and right-sided cardiac catheterization were performed within 4 hours. From continuous-wave Doppler of the tricuspid regurgitation jet, pulmonary artery systolic pressure was calculated as the peak gradient across the tricuspid valve plus right atrial pressure estimated from inferior vena cava filling. Mean pulmonary artery pressure was calculated as (0.61 × pulmonary artery systolic pressure) + 2. Pulmonary vascular resistance (PVR) was calculated as (tricuspid regurgitation velocity/right ventricular outflow tract time-velocity integral × 10) + 0.16. Pulmonary capillary wedge pressure was calculated as 1.91 + (1.24 × E/E'). Pearson's correlation and Bland-Altman analysis of mean differences between echocardiographic and right-sided cardiac catheterization measurements were statistically significant for all hemodynamic parameters (pulmonary artery systolic pressure: r = 0.82, p < 0.05, mean difference 3.1 mm Hg, 95% confidence interval [CI] -0.2 to 6.3; mean pulmonary artery pressure: r = 0.80, p < 0.05, mean difference 2.5 mm Hg, 95% CI 0.3 to 4.6; PVR: r = 0.52, p < 0.05, mean difference 0.8 Wood units, 95% CI 0.3 to 1.4; pulmonary capillary wedge pressure: r = 0.65, p < 0.05, mean difference 2.2 mm Hg, 95% CI 0.1 to 4.3). Compared with right-sided cardiac catheterization, PVR by Doppler echocardiography identified all patients with PVR > 4 Wood units (n = 4), 73% of patients with PVR <2 Wood units (n = 8), and 52% of patients with PVR from 2 to 4 Wood units (n = 10). In conclusion, echocardiographic estimation of cardiopulmonary hemodynamics is reliable in patients with end-stage cardiomyopathy. The noninvasive assessment of hemodynamics by echocardiography may be able to decrease the number of serial right-sided cardiac catheterizations in selected patients awaiting heart transplantation. However, in patients with borderline PVR, right-sided cardiac catheterization is indicated to assess eligibility for transplantation.