The Prognostic Value of Follow-up Hemodynamic Variables After Initial Management in Pulmonary Arterial Hypertension
Background—Hemodynamic variables, such as cardiac index and right atrial pressure (RAP), have consistently been associated with survival in pulmonary arterial hypertension (PAH) at the time of diagnosis. Recent studies have suggested pulmonary arterial compliance (PCa) may also predict prognosis in PAH. The prognostic importance of hemodynamic values achieved after treatment initiation is less well established.
Methods—Our objective was to evaluate the prognostic importance of clinical and hemodynamic variables during follow-up, including PCa, after initial management in PAH. We evaluated incident patients with idiopathic, drug and toxin-induced or heritable PAH enrolled in the French pulmonary hypertension registry between 2006-2016 who had a follow-up right heart catheterization (RHC). The primary outcome was death or lung transplantation. We used stepwise Cox regression and receiver-operating characteristic analysis to assess variables obtained at baseline and at first follow-up RHC.
Results—Of 981 patients, a primary outcome occurred in 331 patients (33.7%) over a median follow-up duration of 2.8 years (IQR25-75% 1.1-4.6). In a multivariable model considering only baseline variables, no hemodynamic variables independently predicted prognosis. Median time to first follow-up RHC was 4.6 months (3.7-7.8). At first follow-up RHC (n=763), New York Heart Association (NYHA) functional class, 6-minute walk distance (6MWD), stroke volume index (SVI), and right atrial pressure (RAP) were independently associated with death or lung transplantation, adjusted for age, gender, and etiology of PAH. PCa did not independently predict outcomes at baseline or during follow-up. The adjusted hazard ratio for SVI was 1.28 (95%CI 1.11-1.49, p<0.01) per 10 mL/m2 decrease, and for RAP was 1.05 (95%CI 1.02-1.09, p<0.01) per mmHg increase. Among patients who had 2 (n=355) or 3 (n=193) low-risk prognostic features at follow-up, including a cardiac index ≥ 2.5 L/min/m2, 6MWD > 440 m and either NYHA I or II functional class, lower SVI was still associated with higher rates of death or lung transplantation (p<0.01).
Conclusions—SVI and RAP were the hemodynamic variables independently associated with death or lung transplantation at first follow-up RHC after initial PAH treatment. These findings suggest that the SVI could be a more appropriate treatment target than the cardiac index in PAH.
- Received May 16, 2017.
- Revision received October 4, 2017.
- Accepted October 11, 2017.