January 14, 2019
Elevated levels of myocardial native T1, a noninvasive cardiovascular magnetic resonance (CMR) marker, are associated with increased interventricular septal angle in patients with pulmonary hypertension (PH), according to a study published in the Journal of Cardiovascular Magnetic Resonance.
Data from 490 patients who underwent clinical 1.5 T CMR evaluation were collected retrospectively and included in the analysis. Patients had either PH (n=369), PH as a result of left heart disease (n=39), or no PH (n=82). In addition, researchers recruited a total of 25 healthy individuals for comparative analyses. A Modified Look-Locker Inversion Recovery (MOLLI) sequence was used for T1 mapping, and a multivariate Cox proportional hazards regression analysis was used to evaluate T1 prognostic value in patients with pulmonary arterial hypertension (PAH).
Higher T1 in the right ventricular insertion point was observed in patients with PAH compared with patients without PAH and healthy controls (patients with PH: 1065±86 ms vs patients without PH: 1017±69 ms and healthy controls: 943±52 ms; P <.001). The right ventricular insertion point was effective for distinguishing between patients with PH and healthy individuals (area under the curve=0.863), but it could not distinguish between patients with PH and without PH (area under the curve=0.654).
Several factors assessed during the study, including septal angle, right ventricle insertion point, and left ventricular wall, were not reliable predictors of overall mortality (P =.552, P =.688, and P =.258, respectively). The only predictor of T1 in patients with PH was systolic interventricular septal angle (P <.001).
The lack of CMR data for some patients, the relatively short follow-up period, and the lack of investigation into the association between T1 and late gadolinium enhancement in the right ventricular insertion points were potential limitations cited by the researchers.
The findings that the “interventricular septal angle independently predicted [right ventricular] insertion point T1 in patients with PAH” suggest “that regional elevation in the [right ventricular] insertion point may be linked to increased stress on the interventricular septal wall.”
Saunders LC, Johns CS, Stewart NJ, et al. Diagnostic and prognostic significance of cardiovascular magnetic resonance native myocardial T1 mapping in patients with pulmonary hypertension. J Cardiovasc Magn Reson. 2018;20(1):78.