Published Online
on May 13, 2009

A more recent version of this article appeared on July 1, 2009

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Original Article

Value of Exercise Treadmill Testing in the Risk Stratification of Patients with Pulmonary Hypertension

Sanjiv J. Shah¹; Thenappan Thenappan²; James Sur²; Stuart Rich²; Stephen L. Archer² and Mardi Gomberg-Maitland^2,3

¹ Northwestern University Feinberg School of Medicine, Chicago, IL;
² University of Chicago, Chicago, IL

http://www.medicine.northwestern.edu/scripts/bio.pl?pid=5822

³ E-mail: mgomberg{at}medicine.bsd.uchicago.edu

Background—The ability of the Naughton-Balke exercise treadmill test (ETT), an objective indicator of exercise capacity, to predict abnormal hemodynamics and mortality in pulmonary hypertension (PH) is unknown.

Methods and Results—We performed a cohort study of 603 patients with PH from 1982-2006, and studied the utility of ETT as a predictor of abnormal hemodynamics and death. We used multivariable linear regression to determine whether exercise capacity, measured in metabolic equivalents (METs), was associated with abnormal hemodynamics, and we used a Cox proportional hazards model to determine whether decreased exercise capacity predicted death. Mean age was 50±15 years, 76% were female, 63% had World Health Organization (WHO) Category I pulmonary arterial hypertension, and 23% were WHO functional class I-II. Mean exercise capacity was 3.7±2.2 METs. Decreased exercise capacity was independently associated with elevated right atrial and mean pulmonary artery pressure, decreased cardiac index, and increased pulmonary vascular resistance. During median follow-up of 4.6 years, 36% of the patients died. Decreased exercise capacity was associated with mortality (multivariable HR 1.18, 95% CI 1.01-1.37 for each 1-MET decrease in exercise capacity, p=0.031; p=0.052 after adjusting for invasive hemodynamic variables). Decreased exercise capacity also predicted mortality in functional class I-II patients, 24% of whom died (HR 1.53, 95% CI 1.04-2.26 for each 1-MET decrease in exercise capacity, p=0.032), although this association did not persist after adjusting for invasive hemodynamic variables (p=0.63).

Conclusions—Reduced exercise capacity on ETT is associated with worse hemodynamics, and is a predictor of mortality in patients with PH.

Key Words: exercise • hemodynamics • mortality • pulmonary hypertension