C66-16 Evaluating Non-invasive Predictors of Pre- and Post-capillary Pulmonary Hypertension

Rationale Pulmonary hypertension (PH) is a condition in which elevated pulmonary arterial pressure leads to significant morbidity and mortality. Etiology can be categorized as pre-capillary due to dysfunction within the arterial vasculature, post-capillary due to increased left-sided cardiac pressure, or mixed. While diagnosis of pre-capillary PH leads to treatment with PH-specific vasodilatory medications, a diagnosis of post-capillary PH is unlikely to change management as therapy is directed at underlying left-sided cardiac dysfunction. Diagnosis and classification of PH is dependent on right heart catheterization (RHC), but this procedure is invasive and may be unavailable in many healthcare settings. Thus, evaluating the ability of non-invasive tests to predict the presence of pre-capillary versus post-capillary PH may determine whether pursuing RHC will be beneficial. Methods We retrospectively collected data for all patients that underwent RHC at our facility confirming a diagnosis of PH over the past two years, which included 79 patients. We classified patients as pre-capillary, post-capillary, or mixed PH per 2022 ERS guidelines. Given a low sample size, post-capillary and mixed PH were combined into a single group for analysis. We analyzed clinical parameters, serum biomarkers, and echocardiographic measurements to evaluate their ability to discriminate pre-capillary from mixed or post-capillary PH using logistic regression models. Two-tailed p < .05 was used to indicate statistical significance. Results Of the 79 patients, 58.2% had pre-capillary PH whereas 41.8% had post-capillary or mixed PH. Each 10% increase in percent-predicted distance on six-minute walk testing (6MWT) was associated with 52% greater odds of post-capillary or mixed PH (95% CI: 3% to 124%, p = .037) and each 0.1-unit higher mitral E/A ratio was associated with 15% greater odds of post-capillary or mixed PH (95% CI: 1% to 32%, p = .043). We found non-statistically significant trends towards pre-capillary PH with higher tricuspid regurgitation (TR) velocity and abnormal tricuspid annular plane systolic excursion (TAPSE). Conclusion Our results suggest non-invasive testing may have utility in predicting the presence of pre-capillary versus post-capillary or mixed PH. Lower percent-predicted on 6MWT suggests pre-capillary PH and thus may indicate benefit in pursuing RHC and initiation of PH-specific therapy. Conversely, diastolic dysfunction as indicated by a higher E/A ratio suggests initial therapy be directed at left-sided cardiac disease before pursuing invasive testing with RHC. The trend towards higher TR velocity and abnormal TAPSE in pre-capillary PH may have lacked statistical significance due to our study’s small sample size limiting its power. This abstract is funded by: None