Background Connective tissue disease (CTD)-associated pulmonary arterial hypertension (PAH), particular in systemic sclerosis (SSc), has lower survival than idiopathic PAH.(1) Additionally, CTD often develops left ventricular (LV) dysfunction.(2) Exercise Doppler echocardiography is useful for diagnosis subclinical early stage pulmonary hypertension (PH).(3)
Objectives To evaluate a validity of exercise Doppler echocardiography for predicting early-stage and borderline PH in CTD patients and to create a formula for estimating mean pulmonary arterial pressure (mPAP) based on exercise Doppler echocardiography for CTD patients.
Methods A total of 231 patients with CTD having either dyspnea or lower carbon monoxide diffusing capacity (DLCO) was performed Doppler echocardiography before and after exercise with the Master’s double two-step. Right-sided heart catheterization (RHC) was recommended in 68 patients (29.4%) who had >45mmHg of tricuspid regurgitation pressure gradient (TRPG) just after exercise Doppler echocardiography (57 patients) or who had unexplained dyspnea or <40% of DLCO (11 patients). RHC was undergone in 32 CTD patients (47.1%). The diagnostic value of exercise Doppler echocardiography was quantified in 32 CTD patients against data obtained from RHC.
Results The 32 patients were consisted of 23 with SSc, 3 with systemic lupus erythematosus, 2 with primary Sjogren syndrome, 3 with mixed connective tissue disease and 1 with dermatomyositis. Mean age (SD) was 60.8 (13.1). Among the 32 patients, 6 patients (18.8%) had borderline PAH and 5 (15.6%) had manifest PAH by Dana Point classification. Notably, 5 patients (15.6%) had >15 mmHg of pulmonary capillary wedge pressure (PCWP) suggesting pulmonary venous hypertension (PVH) from LV dysfunction. TRPG at 3 minutes explained 53% of the variability in the mPAP (r2 =0.5305, P<0.0001), which was higher than TRPG at rest (r2 =0.1860, P=0.0137) or TRPG measured just after the exercise (r2 =0.4673, P<0.0001). We derived a formula for the estimated mPAP =0.551+0.384*TRPG (post 3 minutes) (r2 =0.530, P<0.0001). The proposed formula for estimating mPAP derived from exercise Doppler echocardiography showed good correlation with mPAP by RHC (Spearman r =0.6806, p<0.0001). Receiver operating characteristic curve analysis showed the area under curve by the estimated mPAP was 0.821 (95% CI 0.668-0.975) and the estimated >17.5 mmHg of mPAP by the formula predicted borderline or manifest PH with sensitivity of 86.7% and specificity of 71.4%.
Conclusions Exercise Dopper echocardiography was useful to predict mPAP in the early PH with good sensitivity and specificity. The causes of PH in CTD are heterogeneous. PHC is needed to confirm the diagnosis of PAH and PVH. The validity of the formula should be assessed with another cohort.
Le Pavec J et al. Systemic sclerosis-associated pulmonary arterial hypertension. Am J Respir Crit Care Med, 2010; 181: 1285.
Saggar R et al. Exercise-induced pulmonary hypertension associated with systemic sclerosis. Four distinct entities. Arthritis rheum, 2010; 62: 3741.
Lindqvist P et al. Echocardiography based estimation of pulmonary vascular resistance in patients with pulmonary hypertension: a simultaneous Doppler echocardiography and cardiac catheterization study. Eur J Echocardiography, 2011; 12: 961.
Disclosure of Interest None Declared