Right ventricular stroke work index by echocardiography in adult patients with pulmonary arterial hypertension

Background In adult patients with pulmonary arterial hypertension (PAH), right ventricular (RV) failure may worsen rapidly, resulting in a poor prognosis. In this population, non-invasive assessment of RV function is challenging. RV stroke work index (RVSWI) measured by right heart catheterization (RHC) represents a promising index for RV function. The aim of the present study was to comprehensively evaluate non-invasive measures to calculate RVSWI derived by echocardiography (RVSWI ECHO ) using RHC (RVSWI RHC ) as a reference in adult PAH patients. Methods Retrospectively, 54 consecutive treatment naïve patients with PAH (65 ± 13 years, 36 women) were analyzed. Echocardiography and RHC were performed within a median of 1 day [IQR 0–1 days]. RVSWI RHC was calculated as: (mean pulmonary arterial pressure (mPAP)—mean right atrial pressure (mRAP)) x stroke volume index (SVI) RHC . Four methods for RVSWI ECHO were evaluated: RVSWI ECHO-1 = Tricuspid regurgitant maximum pressure gradient (TR maxPG ) x SVI ECHO , RVSWI ECHO-2 = (TR maxPG -mRAP ECHO ) x SVI ECHO , RVSWI ECHO-3 = TR mean gradient (TR meanPG ) x SVI ECHO and RVSWI ECHO-4 = (TR meanPG –mRAP ECHO ) x SVI ECHO . Estimation of mRAP ECHO was derived from inferior vena cava diameter. Results RVSWI RHC was 1132 ± 352 mmHg*mL*m −2 . In comparison with RVSWI RHC in absolute values, RVSWI ECHO-1 and RVSWI ECHO-2 was significantly higher ( p < 0.001), whereas RVSWI ECHO-4 was lower ( p < 0.001). No difference was shown for RVSWI ECHO-3 ( p = 0.304). The strongest correlation, with RVSWI RHC , was demonstrated for RVSWI ECHO-2 (r = 0.78, p < 0.001) and RVSWI ECHO-1 ( r = 0.75, p < 0.001). RVSWI ECHO-3 and RVSWI ECHO-4 had moderate correlation (r = 0.66 and r = 0.69, p < 0.001 for all). A good agreement (ICC) was demonstrated for RVSWI ECHO-3 (ICC = 0.80, 95% CI 0.64–0.88, p < 0.001), a moderate for RVSWI ECHO-4 (ICC = 0.73 , 95% CI 0.27–0.87, p < 0.001) and RVSWI ECHO-2 (ICC = 0.55, 95% CI − 0.21–0.83, p < 0.001). A poor ICC was demonstrated for RVSWI ECHO-1 (ICC = 0.45, 95% CI − 0.18–0.77, p < 0.001). Agreement of absolute values for RVSWI ECHO-1 was − 772 ± 385 (− 50 ± 20%) mmHg*mL*m −2 , RVSWI ECHO-2 − 600 ± 339 (-41 ± 20%) mmHg*mL*m −2 , RVSWI ECHO-3 42 ± 286 (5 ± 25%) mmHg*mL*m −2 and for RVSWI ECHO-4 214 ± 273 (23 ± 27%) mmHg*mL*m −2 . Conclusion The correlation with RVSWI RHC was moderate to strong for all echocardiographic measures, whereas only RVSWI ECHO-3 displayed high concordance of absolute values. The results, however, suggest that RVSWI ECHO-1 or RVSWI ECHO-3 could be the preferable echocardiographic methods. Prospective studies are warranted to evaluate the clinical utility of such measures in relation to treatment response, risk stratification and prognosis in patients with PAH.