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 (RVSWIECHO) using RHC (RVSWIRHC) 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]. RVSWIRHCwas calculated as: (mean pulmonary arterial pressure (mPAP)—mean right atrial pressure (mRAP)) x stroke volume index (SVI)RHC. Four methods for RVSWIECHOwere evaluated: RVSWIECHO-1 = Tricuspid regurgitant maximum pressure gradient (TRmaxPG) x SVIECHO, RVSWIECHO-2 = (TRmaxPG-mRAPECHO) x SVIECHO, RVSWIECHO-3 = TR mean gradient (TRmeanPG) x SVIECHOand RVSWIECHO-4 = (TRmeanPG–mRAPECHO) x SVIECHO. Estimation of mRAPECHOwas derived from inferior vena cava diameter. Results RVSWIRHCwas 1132 ± 352 mmHg*mL*m−2. In comparison with RVSWIRHCin absolute values, RVSWIECHO-1and RVSWIECHO-2was significantly higher (p < 0.001), whereas RVSWIECHO-4was lower (p < 0.001). No difference was shown for RVSWIECHO-3(p = 0.304). The strongest correlation, with RVSWIRHC, was demonstrated for RVSWIECHO-2(r = 0.78,p < 0.001) and RVSWIECHO-1( r = 0.75,p < 0.001). RVSWIECHO-3and RVSWIECHO-4had moderate correlation (r = 0.66 and r = 0.69,p < 0.001 for all). A good agreement (ICC) was demonstrated for RVSWIECHO-3(ICC = 0.80, 95% CI 0.64–0.88,p < 0.001), a moderate for RVSWIECHO-4(ICC = 0.73,95% CI 0.27–0.87,p < 0.001) and RVSWIECHO-2(ICC = 0.55, 95% CI − 0.21–0.83,p < 0.001). A poor ICC was demonstrated for RVSWIECHO-1(ICC = 0.45, 95% CI − 0.18–0.77,p < 0.001). Agreement of absolute values for RVSWIECHO-1was − 772 ± 385 (− 50 ± 20%) mmHg*mL*m−2, RVSWIECHO-2− 600 ± 339 (-41 ± 20%) mmHg*mL*m−2, RVSWIECHO-342 ± 286 (5 ± 25%) mmHg*mL*m−2and for RVSWIECHO-4214 ± 273 (23 ± 27%) mmHg*mL*m−2. Conclusion The correlation with RVSWIRHCwas moderate to strong for all echocardiographic measures, whereas only RVSWIECHO-3displayed high concordance of absolute values. The results, however, suggest that RVSWIECHO-1or RVSWIECHO-3could 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.