Cardiac MRI identifies raised LV filling pressure; predictive of survival in suspected HF
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Cardiac MRI demonstrated superiority to transthoracic echocardiography in identifying elevated left ventricular filling pressure among patients with suspected HF presenting with breathlessness, researchers reported.
Additionally, cardiac MRI-derived pulmonary capillary wedge pressure — the metric researchers used as reference for LV filling pressure — was found to have similar prognostic value in predicting survival compared with right heart catheterization-measured pulmonary capillary wedge pressure, according to data published in European Heart Journal.
“At a population level, the invasive strategy is not feasible to diagnose and monitor treatment progress in patients with HF. Hence, noninvasive methods are preferred and as such, transthoracic echocardiography (TTE) is the mainstay of initial LV filling pressure assessment,” Pankaj Garg, MD, PhD, MRCP(UK), FESC, associate professor in cardiovascular medicine at the University of East Anglia and honorary consultant cardiologist at Norfolk University Hospital and Norwich University Hospitals, U.K., and colleagues wrote. “Cardiac magnetic resonance (CMR) imaging has emerged as an important imaging tool for clarification of etiology of HF and further sub-phenotyping. The main benefit of CMR is its enhanced precision in functional and volumetric assessment. Currently, there is no CMR model available that predicts LV filling pressure. It also remains unclear if such a CMR model will offer any prognostic advantage.”
Researchers therefore assessed the utility of cardiac MRI to estimate LV filling pressure in patients with suspected HF as well as the prognostic efficacy of MRI-derived LV filling pressure to predict survival.
For this study, researchers enrolled 835 patients (mean age, 65 years; 40% men) who presented with breathlessness and subsequently underwent right heart catheterization and cardiac MRI, each imaging test done within 24 hours of the other. A smaller validation cohort of 127 patients also underwent TTE. The primary endpoint was death.
Right heart catheterization-measured pulmonary capillary wedge pressure, defined as 15 mm Hg or more, was used as a reference for LV filling pressure.
Cardiac MRI vs. TTE in suspected HF
In the derivation cohort of 708 patients with suspected HF who underwent right heart catheterization and cardiac MRI, the two MRI metrics associated with right heart catheterization-measured pulmonary capillary wedge pressure were LV mass and left atrial volume.
When researchers applied these metrics to the validation cohort, the correlation coefficient between right heart catheterization-measured pulmonary capillary wedge pressure and cardiac MRI-derived pulmonary capillary wedge pressure was 0.55 (95% CI, 0.41-0.66; P < .0001).
Compared with TTE, cardiac MRI-derived pulmonary capillary wedge pressure was superior in classifying patients with normal or raised filling pressures (76% vs. 25%), according to the study.
Prognostic value of cardiac MRI
MRI-derived pulmonary capillary wedge pressure was associated with an increased risk for death (HR = 1.77; P < .001) and was comparable to right heart catheterization-measured pulmonary capillary wedge pressure in predicting 7-year survival (35% vs. 37%; X2 = .41; P = .52).
“This CMR LV filling pressure model can easily be incorporated into routine clinical workflows. Volumetric and functional assessment by CMR is rapidly moving from manual segmentation, which takes considerable time and effort, to automated segmentation using artificial intelligence. Our proposed CMR-modeled pulmonary capillary wedge pressure can be generated almost instantaneously once the CMR-derived LV and left atrial volumetric assessments have been made,” the researchers wrote. “Future studies are warranted to investigate not only the emerging complementary role of CMR to estimate LV filling pressure but also the incremental role of advanced echocardiographic methods in routine estimation of LV filling pressure.”
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