A total of 66 patients with SLE with or without PAH and 30 healthy control subjects were enrolled. Controls were age-matched to patients with SLE and without PAH. All patients completed the 6-minute walking distance (6MWD) test and underwent standard echocardiography. Tricuspid FPV was measured in the modified parasternal short-axis view using the color M-mode technique. PAH was defined as PASP > 35 mm Hg using the tricuspid regurgitant method.
Patients with SLE and PAH had significantly lower tricuspid FPVs and 6MWDs than patients in the other 2 groups (both P values < .001). Tricuspid FPV was well correlated with 6MWD (r = 0.748, P < .001). In multivariate analysis, right atrial pressure was the only independent factor affecting tricuspid FPV (R2 = 0.394, P < .001), and 6MWD was affected only by tricuspid FPV and PASP (R2 = 0.629, P < .001). Patients with SLE who had been readmitted had lower tricuspid FPVs than those who had not (P = .035). Furthermore, FPV ?35.4 cm/s predicted 6MWD ?350 m and a lower 1-year readmission rate with good sensitivity and specificity.
The tricuspid FPV technique provides a simple method for predicting exercise tolerance, the severity of PAH, and readmission among patients with SLE.