Of 531 patients screened by echocardiography, 84 (15.8%) underwent RHC. Right heart catheterization was performed in 81 of 243 patients with a TRV of 2.5 m/s or greater, 67 of 128 with a TRV of 2.8 m/s or greater, 58 of 88 with a TRV of 3 m/s or greater, and 56 of 63 with both a TRV of 2.8 m/s or greater and a 6-minute walk distance of less than 500 m. Fifty-five patients had pulmonary hypertension (65.5% of those who underwent RHC and 10.4% of the total population) and 29 did not. Patients with pulmonary hypertension were older than those who did not undergo RHC and had lower levels of hematocrit and higher serum levels of lactate dehydrogenase, aspartate aminotransferase, direct bilirubin, and ferritin (). Patients with pulmonary hypertension demonstrated significantly abnormal cardiopulmonary markers and exercise capacity.
Clinical Characteristics of Patients With Sickle Cell Disease by Pulmonary Hypertension Status
The median follow-up time since enrollment was 4.4 years, with a maximum of 9.6 years. A total of 73 deaths were observed. The overall mortality was worse in the pulmonary hypertension group (20 deaths, 6-year mortality of 37% [95% CI, 20%–50%]) than in either the group without pulmonary hypertension (3 deaths, 6-year mortality of 13% [95% CI, 0%–26%]; age-adjusted HR, 3.43 [95% CI, 1.02–11.55]; P = .047) or the group without RHC (50 deaths, 6-year mortality of 17% [95% CI, 12%–21%]; age-adjusted HR, 2.14 [95% CI, 1.25–3.67]; P = .006) (, part A). Estimated median survival time was 6.8 years after ascertainment of pulmonary hypertension. Patients with SCD and pulmonary hypertension also died at a younger age than the group without RHC (, part B).
Kaplan-Meier Estimates of Survival for Patients With Sickle Cell Disease by Pulmonary Hypertension Status