Abstract 15290: 4D-flow MRI Intracardiac Flow Hemodynamic Patterns Can Phenotype Different Subtypes of Pulmonary Hypertension

Abstract

Introduction: Idiopathic Pulmonary Arterial Hypertension (PH-Type I) and PH due to pulmonary disease (PH-Type III) arise from different pathophysiologic processes, yet they both culminate in increased right ventricular (RV) afterload and eventual RV failure. Previous work has demonstrated that 4D-Flow MRI-derived intracardiac vorticity (ω) correlates with markers of ventricular interdependency and diastolic dysfunction in PH. However, no investigation has attempted to use both ω and standard markers of ventricular function to phenotype PH subgroups. Hypothesis: 4D-Flow MRI can detect differences in diastolic dysfunction that make it possible to phenotype patients with Type I and Type III PH. Methods: Type I PH patients (n=12, mean age 61yrs), Type III PH patients (n=15, mean age 63yrs), and healthy controls (n=10, mean age 58yrs) underwent standard cardiac MRI as well as 4D-Flow MRI to determine RV intracardiac flow markers including early (ω-E) and late (ω-A) diastolic vorticity. Standard MRI-based RV and LV size and function markers were also collected. Results: ω-E was decreased in the Type I PH group compared to the Type III PH group (P=0.035) and to controls (P<0.001). There was no difference in ω-E between the Type III group and controls (P=0.216). RVEF was decreased in both the Type I (P<0.001) and Type III (P=0.012) group compared to controls. There was no difference in RVEF between the Type I and Type III groups (P=0.917). RVEDV was increased in both the Type I (P=0.008) and Type III (P=0.006) groups compared to controls. No significant differences were noted between groups when assessing (ω-A) and other RV or LV standard volume and functional indices. Conclusion: Our results indicate that 4D-Flow MRI can distinguish among different PH subtypes using intracardiac diastolic vorticity. Comparative studies with standard echocardiography and catheterization are necessary to assess the sensitivity of 4D-Flow MRI to detect diastolic dysfunction.