Additional role of echocardiogram in pulmonary arterial hypertension risk stratification according to current ESC/ERS guidelines

Abstract

Abstract Background Current pulmonary hypertension (PH) guidelines stratify the risk of patients with pulmonary arterial hypertension (PAH) using a multiparametric approach. A simplified risk table has been recently proposed and validated without including echocardiographic parameters. Purpose We evaluate the additional role of echocardiogram in PAH risk stratification using the recently proposed simplified risk table in patients with idiopathic/heritable (I/H) PAH and PAH associated with connective tissue disease (CTD) and congenital heart disease (CHD). Methods All patients with I/H-PAH, CTD-PAH and CHD-PAH referred to a single centre were included from 2003 to 2017. All patients were treated according to PH guidelines. The simplified risk assessment considered the following criteria: WHO functional class, 6-min walking distance, right atrial (RA) pressure or brain natriuretic peptide (BNP) plasma levels and cardiac index (CI) or mixed venous oxygen saturation (SvO2). For the last 2 criteria the worst parameter was chosen. Risk strata were defined as: Low risk= at least 3 low risk and no high-risk criteria; High risk= at least 2 high risk criteria including CI or SvO2; Intermediate risk= definitions of low or high risk not fulfilled. Then we performed a Cox analysis to evaluate the independent echocardiographic predictors of survival that were subsequently added to the simplified risk table to test their additional role in ameliorating risk stratification. Results 461 treatment-naïve patients were enrolled. Echocardiographic independent predictors of prognosis were the severity of tricuspid regurgitation [HR (95% CI) = 1.013 (1.006–1.021); p-value = 0.001], right atrial area [HR (95% CI) = 1.028 (1.012–1.045); p-value = 0.001] and the presence of pericardial effusion [HR (95% CI) = 1.533 (1.142–2.057); p-value= 0.004]. Only RA area significantly ameliorate the risk stratification power of the recently validated simplified PAH risk table (likelihood ratio chi2 increased from 63.8 to 68.1, likelihood ratio test = 0.039). Due to the significant correlation between RA area and both RA pressure (r=0.470; p<0.001) and BNP (r=0.372; p=0.004), we elaborate a second risk table in which RA area (utilizing the cut-offs proposed by the current PH guidelines) was considered together within the criteria including RA pressure and BNP (the worst parameter of the 3 was considered). Considering the second risk table including RA area the risk stratification power significantly improved (likelihood ratio chi2 increased from 63.8 to 72.7, AIC/BIC decreased from 1956/1964 to 1947/1955). Conclusions Echocardiographic RA area significantly improve the risk discrimination power of the recently proposed simplified risk table for patients with PAH. Funding Acknowledgement Type of funding source: None