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The following is a summary of “iCPET Calculator: A Web‐Based Application to Standardize the Calculation of Alpha Distensibility in Patients With Pulmonary Arterial Hypertension,” published in the October 2023 issue of Cardiology by Elliott et al.
Pulmonary vascular distensibility holds significance in assessing proper ventricular function and prognosis in individuals experiencing unexplained dyspnea and pulmonary hypertension. The alpha distensibility coefficient is derived from nonlinear pressure-flow analyses and serves as a crucial metric. This study aimed to develop and validate a user-friendly tool to streamline the analysis of exercise-related hemodynamics, including distensibility, and investigate alterations in distensibility post-treatment among pulmonary arterial hypertension patients.
Participants from the University of Arizona Pulmonary Hypertension (UA PH) registry underwent exercise right heart catheterization and were categorized into pulmonary arterial hypertension, comparator, and control groups. Assessment of right ventricular function involved quantifying the coupling ratio and diastolic stiffness. Prototypes of the invasive cardiopulmonary exercise testing (iCPET) calculator were created using Matlab, Python, and RShiny to analyze exercise-related hemodynamics and alpha distensibility coefficient (α – %/mm Hg) from multipoint pressure-flow plots. Interclass correlation coefficients were computed to gauge interplatform and interobserver variability in alpha values, revealing no significant bias in intraplatform (Matlab vs. RShiny; intraclass correlation coefficient: 0.996) or interobserver (intraclass correlation coefficient: 0.982) comparisons. Following treatment, the pulmonary arterial hypertension group exhibited a significant decrease (P<0.05) in afterload without concurrent changes in alpha distensibility.
Conversely, the comparator group showed no pressure, resistance, or alpha distensibility alterations. Moreover, no substantial modifications in RV diastolic stiffness were observed during the follow-up period.
The iCPET calculator’s interactive interface facilitates standardized exploration of alpha distensibility. The absence of significant changes in alpha distensibility during follow-up suggests its lesser adaptability in patients grappling with long-standing pulmonary arterial hypertension.
Source: ahajournals.org/doi/10.1161/JAHA.123.029667
