Background Early identification and treatment of pulmonary arterial hypertension (PAH) may improve survival of connective tissue diseases (CTD) such as scleroderma (SSc).(1) Exercise Doppler echocardiography helps to select patients who need right-sided heart catheterization (RHC) and therapeutic introduction.(2) Last year we have introduced a formula for estimating mean pulmonary arterial pressure (mPAP) using exercise Doppler echocardiography for CTD patients.(3)
Objectives To construct an applicable formula for selecting CTD patients with early phase of pulmonary hypertension (PH) who need RHC based on the results of their exercise Doppler echocardiography.
Methods A total of 231 CTD patients having either dyspnea or lower carbon monoxide diffusing capacity (DLCO) were performed Doppler echocardiography before and after exercise with the Master’s double two-step. RHC was recommended in 68 patients (29.4%) who had >45mmHg of tricuspid regurgitation pressure gradient (TRPG) just after exercise Doppler echocardiography or who had unexplained dyspnea or <40% of DLCO, and 32 patients (47.1%) (72% were SSc) agreed to undergo RHC. We derived a formula estimating mPAP using the data from the 32 patients and validated the formula with the additional 16 CTD patients (75% were SSc).
Results The 32 CTD patients for the derivation consisted of 6 (18.8%) with borderline PH and 5 (15.6%) with manifest PH by Dana Point classification. TRPG measured 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). The formula we have derived for estimating borderline or manifest PH was the following: estimated mPAP = 0.551+0.384 x TRPG (post 3 minutes) (r2 = 0.530, P <0.0001).
Applying the formula to the validation cohort of 16 CTD patients with borderline PH (n = 3) and manifest PH (n = 5), whose age and sex did not significantly differ from the derivation group, gave a good correlation between the estimated mPAP and actual mPAP by RHC (Spearman r =0.7646, p =0.0006). In receiver operating characteristic, the area under the curve was 0.841. Using an estimated threshold of 15.5 mmHg for diagnosis of borderline and manifest PH, the sensitivity and specificity were 88.9% and 57.1%, respectively.
Conclusions We derived and validated the formula using exercise Doppler echocardiography for estimating mPAP. The provided formula would help the selection of candidate patients for RHC and early detection of PH in CTD patients.
Nihyyanova SI et al. Improved survival in systemic sclerosis is associated with better ascertainment of internal organ disease: a retrospective cohort study. QJM, 2010; 103: 109.
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.
Yamasaki Y et al. Detection of borderline pulmonary hypertension using exercise Doppler echocardiography in patients with connective tissue diseases. EULAR 2012.
Disclosure of Interest None Declared