Background: Pulmonary hypertension is a clinically useful predictor of death in patients with heart failure. Whether pulmonary hypertension has the same prognostic value among specific underlying causes of cardiomyopathy is unknown. Using a diverse cohort of cardiomyopathy patients, we tested the hypotheses that (1) elevated mean pulmonary arterial pressure is the most important hemodynamic predictor of death and (2) the prognostic value of mean pulmonary pressure varies among different cardiomyopathies.
Methods and results: Patients (n=1134) with new cardiomyopathy were prospectively assigned a specific diagnosis on the basis of clinical evaluation and endomyocardial biopsy. All patients underwent right heart catheterization at baseline and were followed for an average of 4.4 years. In multivariate Cox models that allowed for nonlinear relations between hemodynamics and death, mean systemic pressure (mSP) and mean pulmonary arterial pressure (mPA) emerged as the most important hemodynamic predictors of death. Moreover, there was a statistically significant positive interaction between mPA and the diagnosis of myocarditis. For each 5-mm Hg increase in baseline mSP, mortality rates decreased with relative hazard (RH) of 0.89 (0.86 to 0.92). For a 5-mm Hg increase in baseline mPA, mortality rates increased in patients who did not carry the diagnosis of myocarditis with RH 1.23 (1.17 to 1.29); among patients with myocarditis, mortality rates increased substantially with RH of 1.85 (1.50 to 2.29; P<0.001 for interaction).
Conclusions: Baseline mPA is particularly important for stratifying risk in myocarditis. These findings suggest that secondary pulmonary hypertension may have different biological features in myocarditis and that patients with pulmonary hypertension and myocarditis should be targeted for aggressive medical therapy.