Precapillary pulmonary hypertension: RVOT systolic flow profile as a usuful tool

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction In patients (pts) with pulmonary hypertension (PH), right ventricular outflow tract (RVOT) systolic Doppler flow envelope is frequently abnormal, showing a mid-systolic notch that suggests elevation of pulmonary vascular resistance (PVR). Recent studies have demonstrated that other parameters, such as time-to-notch, may be indicators of elevated pulmonary artery pressures (PAP) and disease severity, conveying an important prognostic value. Purpose To evaluate the correlation between RVOT systolic flow morphology and hemodynamic parameters in pts with PH. Methods Retrospective, single-center study of consecutive pts diagnosed with pulmonary arterial hypertension (PAH) and chronic thromboembolic PH (CTEPH). We included pts who performed right heart catheterization (RHC) and transthoracic echocardiogram (TTE) within a six month period. RVOT systolic Doppler flow envelope was analyzed by measuring the ejection time (ET), time-to-notch (TN), pulmonary acceleration time (PAT), deceleration slope, pre- and post-notching velocity peak. Clinical, epidemiological, TTE and RHC data were recorded. For statistical analysis, Student's T tests, Chi-square and non-parametric tests were performed when appropriate. Results We included 79 pts, 42 with PAH (53%) and 37 with CTEPH (47%). 52 pts were women (66%) with a mean age of 58.06 ± 15.3 years. The mean follow-up (FUP) was 3.6±2.8 years. Most pts (92.3%) were symptomatic with a WHO functional status of II or III, despite specific PH treatment (69.4% PDE5 inhibitors, 63% endothelin receptor antagonists). In our analysis a higher TN correlated negatively with hemodynamic parameters such as mPAP (p = 0.02), PVR (p = 0.015), and mean right atrial pressure (mRAP), (p = 0.02). Similarly, pts with higher ET showed lower mPAP and sPAP in right ventricular catheterization (p = 0.044, p = 0.05 respectively). As previously reported, lower PAT showed a positive association with sPAP (p = 0.008), pulse pressure in pulmonary artery (p = 0.028), mRAP (p = 0.022), cardiac index (p = 0.01) and pulmonary vascular resistance (p = 0.04). When attempting to stratify TN and ET we noted a positive correlation with higher COMPERA score during FUP and lower clinical events, despite lack of clear statistical significance (p = 0.1). Regarding the remaining RVOT flow variables no statistically significant correlations were found. Conclusion This study shows that TN and ET accurately correlate with PAP and PVR, mirroring disease severity. Therefore, RVOT systolic flow profile is a non-invasive parameter that can be used as a valid tool when evaluating patients with PH.