Cardiovascular magnetic resonance (CMR) imaging of right ventricular (RV) function during exercise effectively risk stratifies patients with pulmonary arterial hypertension (PAH) according to RV inotropic reserve, according to study results published in the Journal of Heart and Lung Transplantation.
A total of 20 patients with PAH underwent RV and left ventricular end-diastolic volume and end-systolic volume, stroke volume (SV), and cardiac output assessments using CMR imaging during rest and during exercise.
Patients included in the study were deemed to be at low risk for mortality. Imaging was performed at 6-month intervals, resulting in a total of 44 scans. The investigators compared exercise measurements with resting cardiac conditions and clinical assessment.
The SV response to exercise was between −23 mL to +24 mL (normally distributed; mean 0±12 mL). During exercise, a larger RV end-diastolic volume was associated with reduced SV (7-mL reduction in SV/100 mL RV increased volume).
World Health Organization Functional Class (WHO FC) II correlated with reduced SV during ergometer exercise. In addition, WHO FC I correlated with increased SV (WHO FC I increase of 7%; P <.001 and WHO FC II decrease of 8%; P =.02; difference between FCs, P <.001).
Study limitations included the small sample size, the lack of exercise testing before exercise CMR imaging, and the inclusion of only patients at low risk for PAH.
“Cardiac response during exercise CMR is related to established measurements of morbidity and mortality, as demonstrated in RV dilation and reduced SV during exercise,” the researchers concluded. “SV response during exercise may be useful for future risk evaluation in patients with PAH.”
Göransson C, Vejlstrup N, Carlsen J. Exercise cardiovascular magnetic resonance imaging allows differentiation of low-risk pulmonary arterial hypertension [published online January 25, 2019]. J Heart Lung Transplant. doi:10.1016/j.healun.2019.01.1305