Six-Minute Walk Test Predictive for Pulmonary Hypertension
6MW stress echocardiography noninvasively predicts PH development in connective tissue disease
TUESDAY, July 21, 2015 (HealthDay News) -- The six-minute walk (6MW) stress echocardiography test is prognostic for development of pulmonary hypertension (PH) in connective tissue disease (CTD), according to a study published in the July 28 issue of the Journal of the American College of Cardiology.
Kenya Kusunose, M.D., Ph.D., from the Tokushima University Hospital in Japan, and colleagues performed 6MW stress echocardiographic studies in 78 CTD patients at baseline and follow-up. For five years, patients underwent annual echocardiographic follow-up studies.
The researchers found that 16 patients reached the clinical end point of PH development and none died during a median follow-up period of 32 months. In all 16 patients, PH was confirmed by right heart catheterization. Correlations were seen for development of PH with 6MW distance (hazard ratio [HR], 0.99; P = 0.010), early diastolic tricuspid annulus motion velocity (HR, 0.79; P = 0.025), and absolute difference in mean pulmonary artery pressure (ΔmPAP)/absolute difference in cardiac output (ΔQ) (HR, 1.10; P = 0.005). A model on the basis of 6MW distance was improved by ΔmPAP/ΔQ (chi-square: 6.6 to 14.4; P = 0.019). The best cutoff value of ΔmPAP/ΔQ for predicting PH development was >3.3 mm Hg/l/min.
"The 6MW stress echocardiography noninvasively provides an incremental prognostic value of PH development in CTD," the authors write. "Larger multicenter studies are warranted to confirm the result."