Cardiac Performance During Exercise Predicts PAH Patient Outcome
Evaluating pulmonary arterial hypertension patients for heart performance parameters during exercise shortly after diagnosis allows for a good indication of the chance of survival for the patient, as noted in a study published in European Respiratory Journal. The team from France who published the study investigated 55 patients with idiopathic, familial, or anorexigen-associated pulmonary arterial hypertension.
The researchers were interested in exercise cardiac index and New York Heart Association (NYHA) functional class as the haemodynamic exercise variables and six-minute walking distance and survival as the prognostic variables. Cardiac index is a measure of cardiac output compared to body surface area. Normal measures at rest are 2.6-4.2 L/min/square meter, and 1.8 L/min/square meter indicates a problem. NYHA functional class categorizes individuals into one of four classes based on the severity of symptoms during physical activity. The lower the classification, the better (less/no pain or fatigue) cardiac disease patients feel when exercising.
Baseline evaluations showed exercise cardiac index decreased with an increase in NYHA functional class, but there was no difference in resting cardiac index across groups. All 55 patients were treated for their pulmonary arterial hypertension and 20 were re-evaluated three-to-five months later. Thereafter, all 55 patients were evaluated every three-to-six months.
Monitoring the patients over time, the researchers found six-minute walking distance improved as exercise cardiac index increased. In terms of survival, the best predictor was again exercise cardiac index. At the final evaluation time, 25 patients had succumbed to the disease. Survival rates were 87%, 81%, and 69% after one, two, and three years, respectively.
Lead author Ari Chaouat concluded that “change in pulmonary haemodynamics during exercise is an important tool for assessing disease severity and may help devise optimal treat-to-target strategies.” If patients have poor cardiac performance, a more aggressive strategy to treat their pulmonary arterial hypertension may be warranted.