Is pulmonary vascular resistance index better than pulmonary vascular resistance in predicting outcomes in pulmonary arterial hypertension?

Geometric remodeling of tricuspid valve in pulmonary hypertension and its correlation with pulmonary hypertension severity: a prospectively case-control study using four-dimensional automatic tricuspid valve quantification technology

Background

Evaluation of the tricuspid valve (TV) is crucial for clinical decision making and post-treatment follow-up in pulmonary hypertension (PH) patients. However, little is known about 4-dimensional (4D) TV geometric remodeling in patients with PH. The aim of this study was to examine the 4D geometry of the TV in PH and its correlation with PH severity.

Methods

A total of 74 PH patients with mean pulmonary arterial pressure >25 mmHg and 15 age- and gender-matched healthy individuals were consecutively included from September 2017 to December 2018 in National Center for Cardiovascular Diseases, Fuwai Hospital. All participants underwent 2-dimensional (2D) and 4D transthoracic echocardiography and PH patients underwent right heart catheterization (RHC) within 48 hours of echocardiography. TV geometry was analyzed using a dedicated 4D echocardiography from the right ventricular-focused apical view.

Results

Compared with controls, PH patients had significantly larger 4D tricuspid annular (TA) and TV tenting sizes except in the 2-chamber diameter. In high-quality image cases, maximal tenting height (MTH), coaptation point height, tenting volume and 4-chamber diameter had good or moderate correlation with PH severity graded according to RHC mean pulmonary artery pressure (r=0.705, r=0.644, r=0.602, r=0.472, respectively; P<0.001 for all). In multivariable linear regression analysis, PH severity was independently associated with coaptation point height (F=18.070, P<0.001 with an R2=0.647) and MTH (F=25.576, P<0.001 with an R2=0.378). Among all 4D TV parameters, MTH had the highest area under the receiver operating characteristic (ROC) curve (AUC) in high-quality image cases [AUC =0.857, 95% confidence interval (CI): 0.743-0.972; P<0.001], comparable to echocardiographic systolic pulmonary arterial pressure (AUC =0.847, 95% CI: 0.733-0.961; P<0.001).

Conclusions

In PH, TV geometric remodeling occurs mainly in TA septal-lateral dimension and TV tenting height. Worsening PH is an independent determinant of TV coaptation point height and MTH, not TA size. MTH shows a great diagnostic potential to detect severe PH.

Impact on Pulmonary Hypertension Hemodynamic Classification Based on the Methodology Used to Measure Pulmonary Artery Wedge Pressure and Cardiac Output

Rationale: Guidelines recommend using end-expiration pulmonary pressure measurements to determine the hemodynamic subgroups in pulmonary hypertension. Pulmonary artery wedge pressure (PAWP) determinations averaged across the respiratory cycle (PAWPav) instead of PAWP at end-expiration (PAWPee) and cardiac output (CO) measured by Fick (COFick) instead of thermodilution (COTD) may affect the hemodynamic classification of pulmonary hypertension. Objectives: To assess the impact on the pulmonary hypertension hemodynamic classification of the use of PAWPee versus PAWPav as well as COFick versus COTD. Methods: This was a single-center retrospective study of consecutive patients (n = 151) who underwent right heart catheterization with COTD, COFick, PAWPee, and PAWPav. A secondary cohort consisted of consecutive patients (n = 71) who had mean pulmonary artery pressure at end-expiration (mPAPee) and mPAP averaged across the respiratory cycle (mPAPav) measured, as well as PAWPee and PAWPav. Results: The PAWPee and PAWPav were 16.8 ± 6.4 and 15.1 ± 6.8 mm Hg, respectively, with a mean difference of 1.7 ± 2.1 mm Hg. The COTD and COFick determinations were 5.0 ± 2.4 and 5.3 ± 2.5 L/min, respectively, with a mean difference of -0.4 ± 1.3 L/min. The hemodynamic group distribution was significantly different when using PAWPee versus PAWPav, when using either COTD or COFick (P < 0.001 for both comparisons), and these results were consistent in our secondary cohort. The pulmonary hypertension hemodynamic group distribution was not significantly different between COTD and COFick when using either PAWPee or PAWPav. Conclusions: The methodology used to measure PAWP, either at end-expiration or averaged across the respiratory cycle, significantly impacts the hemodynamic classification of pulmonary hypertension.

Pulmonary hypertension due to high cardiac output

Pulmonary hypertension (PH) is usually associated with a normal or decreased cardiac output (CO). Less commonly, PH can occur in the context of a hyperdynamic circulation, characterized by high CO (>8 L/min) and/or cardiac index ≥4 L/min/m² in the setting of a decreased systemic vascular resistance. PH due to high CO can occur due to multiple conditions and in general remains understudied. In this review article we describe the pathophysiology, etiology, diagnosis, hemodynamic characteristics, and management of PH in the setting of high CO. It is important to recognize this distinct entity as PH tends to improve with treatment of the underlying etiology and PH specific therapies may worsen the hemodynamic state.