PURPOSE: Despite recent advances in the successful treatment of pulmonary hypertension (PH), non-invasive diagnosis of this disorder remains a challenge. Right heart catheterization (RHC), which directly measures pulmonary artery pressure, is necessary to definitively establish the diagnosis. Clinicians frequently utilize physical examination and echocardiography to diagnose PH without subjecting patients to an invasive procedure; this, however, has proved inferior to RHC. We seek to establish a novel diagnostic parameter utilizing cardiac magnetic resonance imaging (MRI) to diagnose PH.
METHODS: We retrospectively reviewed charts of patients (n=39) who have had (within a one month period) a cardiac MRI, a RHC and a 2D-echocardiogram in the last five years. We investigated the relationship of various MRI parameters to the mean pulmonary artery pressure achieved by RHC.
RESULTS: The Laith Index (LI), which is the ventricular mass index multiplied by the atrial size index showed a statistically significant difference in patients with and without PH. The LI was 0.44 and 0.17 in patients with and without PH, respectively (p=0.021). Among subjects with a pulmonary capillary wedge pressure (PCWP) < 18mmHg, the LI approached significance (0.81 vs 0.17, p=0.067). A LI of 0.24 was more sensitive (75%) but less specific (45%) than 2D-echocardiography (67% for each) in diagnosing PH in all patients. In patients with PCWP < 18, the LI was more sensitive (79%) and more specific (75%) in diagnosing PH than 2D-echocardiogram (71% for each).
CONCLUSIONS: The cardiac MRI derived LI was significantly different in patients with and without PH. In patients with PCWP less than 18, it was more sensitive and specific than echocardiography in diagnosing PH.
CLINICAL IMPLICATIONS: Cardiac MRI may serve as a reliable noninvasive tool in the diagnosis of PH. While the LI showed promise in our study group, we hypothesize that its utility may be even more marked in the subgroup of patients excluding group II PH (left-sided heart disease). The lack of sufficient number of subjects in this subgroup limits our findings.
DISCLOSURE: The following authors have nothing to disclose: Ahmad Abdelwahed, Emile Klada, Pramil Vaghasia, Hary Suseelan, Nripen Dontineni, Bassem Phillip, John Heitner, Jeremy Weingarten
No Product/Research Disclosure Information