Role of echocardiography to avoid misclassification of pulmonary hypertension associated with left heart disease as precapillary pulmonary hypertension
Authors: Janssen B , Trujillo P , Grignola Rial J 
Published: October 2021

Abstract

Background
The proportion of patients (pts) diagnosed with pulmonary arterial hypertension (PAH) at a more advanced age and/or with more risk factors for left ventricular diastolic dysfunction is increasing. Therefore, it can be challenging to differentiate PH associated with left heart disease (PH-LHD, PHpost) from other precapillary forms of PH (PHpre).

Purpose
We analyzed the performance of the Opotowsky (OS), D'Alto (DS), and simplified D'Alto (sDS) echocardiographic scores according to the pretest probability (before right heart catheterization – RHC) of PH-LHD in pts with suspected PH submitted to RHC to identify the hemodynamic phenotype.

Methods
37 consecutive stable pts (3/2018–3/2020) with a tricuspid regurgitation peak velocity &gt;2.8 m/s were prospectively included (21F, 49±17 yrs). Blinded transthoracic echocardiography was performed within 2 hours of RHC. We assessed OS (−2 to 2 points) and DS/sDS (0 to 34/7 points). We estimated cardiac index (thermodilution) and hemodynamic parameters using standard formulas. If PA occlusion pressure (PAOP) cannot properly be measured at end-expiration, we assessed left ventricular end-diastolic pressure (LVEDP). PH was defined as a mean PA pressure (mPAP) ≥25 mmHg. PAOP/LVEDP &gt;15 mmHg defined PHpost. If the PAOP/LVEDP was between 13–15 mmHg in an I pt, a volume challenge was done. We categorized pts according to the pretest probability of PH-LHD proposed in the 6th WSPH based on the combination of 7 noninvasive variables (age, presence of CV comorbidities, presence of current or paroxysmal atrial fibrillation, prior cardiac intervention, presence of structural LHD, presence of left bundle branch/LV hypertrophy or RV strain in ECG, presence of left atrial dilatation/grade &gt;2 mitral flow in Echo). The individual average probability was calculated by assigning a score of 1, 2, and 3 for each variable (1 = low (L), 2 = intermediate (I), and 3 = high (H) probability) rounding the average of the sum of values allocated for each variable to the nearest integer. Nonparametric ROC plots assessed the performance of echo-scores.

Results
All pts had PH. 19 pts showed PHpost, 10/19 with PVR &gt;3Wu (Combined PHpost). All scores were lower in PHpost compared to PHpre pts (p&lt;0.05) (Table 1). ROC area was &gt;0.9 with a similar Youden index (0.83) among the three scores (p&lt;0.05) (Figure 1). 17 PHpost with H pts were correctly identified by all scores (94–100%). In 15 PHpre with L pts OS performed better than DS/sDS (93 vs. 80%). In 3 PHpre and 2 PHpost with I pts, DS/sDS performed better than OS (100 vs. 80%).

Conclusion
The use of simple echo-scores could facilitate the screening of the hemodynamic phenotype in pts with PH, regardless of the pretest probability of PH-LHD. D'Alto scores might have some advantage compared to OS to classify the intermediate pretest probability of PH pts correctly.

Funding Acknowledgement
Type of funding sources: Public hospital(s). Main funding source(s): Centro Cardiovascular Universitario. Hospital de Clínicas. Facultad de Medicina. Universidad de la República Table 1. Echo & Hemodynamic DataFigure 1. ROC curves of Echo scores