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mPAP/CO relationship predicts PAH transplant-free survival

The relationship between mean pulmonary arterial pressure to cardiac output during supine incremental exercise was a predictive factor in transplant-free survival among patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, according to recent research.

“This study demonstrated that [mean pulmonary arterial pressure to cardiac output (mPAP/CO)] relationship during exercise [right heart catheterization] computed as multipoint linear regression and simple two-point slope are predictive for transplant-free survival in a collective of patients with [pulmonary arterial hypertension] or distal [chronic thromboembolic pulmonary hypertension (CTEPH)],” Elisabeth Domenica Hasler, MD, of the Pulmonary Clinic at University Hospital Zurich in Switzerland, and colleagues wrote. “The fact that a steep pressure-flow relationship during exercise was not only a predictor of transplant-free survival but also correlated to patients’ relevant outcomes such as [quality of life], [WHO-functional class (WHO-FC)] and exercise capacity may indicate that pressure-flow relationship has the potential to serve as prognostic and outcome parameter in the management of PH patients and potentially clinical trials.”

Hasler and colleagues evaluated the hemodynamic data by right heart catheter in 70 patients (mean age, 65 years) with either PAH (n = 54) or CTEPH (n= 16) both at rest and during a period of supine incremental exercise, according to the abstract. They used Kaplan-Meier and Cox-regression analyses to analyze the rate of transplant-free survival and predictive value of hemodynamics, respectively.

After a median observational period of 610 days, the researchers found that transplant-free survival was 89% at 1 year, 81% at 3 years, 71% at 5 years and 59% at 7 years, according to the abstract. Overall, 14% of patients (10 patients) died and 4% (3 patients) received transplants. Hasler and colleagues found factors such as age, 6-minute walk distance, mixed-venous sulfur dioxide and WHO-functional class impacted transplant-free survival; however, resting hemodynamics were not a factor that predicted transplant-free survival. Specifically, mPAP/CO had an area under the curve of 0.802 (95% CI, 0.66-0.95) that predicted 3-year transplant survival.

During exercise, researchers noted factors such as mPAP/CO (HR = 1.02; 95% CI, 1.01-1.03), maximal workload (HR = 0.94; 95% CI, 0.89-0.99), peak cardiac index (HR = 0.51; 95% CI, 0.27-0.95) and cardiac index change (HR = 0.25; 95% CI, 0.06-0.94) predicted survival, according to the abstract. – by Jeff Craven

Disclosure: Hasler reports no relevant financial disclosures. One researcher reports paid support from Actelion SA, Bayer SA, Orpha Swiss SA. Please see the full study for a list of all other researchers’ relevant financial disclosures.