Pulmonary hyperinflation reduction improves cardiac measures in severe emphysema
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Decreasing pulmonary hyperinflation using bronchoscopic lung volume reduction improved cardiac preload, contractility and output in a cohort of patients with emphysema, according to study findings.
“This is the first study to extensively assess cardiac function after bronchoscopic lung volume reduction (BLVR) with endobronchial valves,” Marieke C. van der Molen, MD, study investigator and PhD candidate at University of Groningen in Groningen, the Netherlands, told Healio.
According to van der Molen, emphysema severity in patients with COPD has repeatedly been associated with decreased cardiac chamber sizes.
“The presence of concomitant heart failure strongly impacts morbidity and mortality in this patient group,” she said.
Van der Molen and colleagues posited that hyperinflation reduction would enhance cardiac preload in patients with severe emphysema, and they evaluated whether the treatment would result in elevated pulmonary artery pressures due to pulmonary vascular bed reduction.
The researchers enrolled 24 patients with emphysema and severe hyperinflation, which was defined as a baseline residual volume greater than 175% of predicted; all patients were eligible for BLVR with endobronchial valves. Researchers acquired cardiac MRI 1 day before treatment and at 8-week follow-up.
Cardiac preload — measured by the right ventricle end-diastolic volume index — served as the primary endpoint. Secondary endpoints included end-diastolic and end-systolic volumes of the right ventricle, left atrium and left ventricle; pulmonary artery pressures; cardiac output; ejection fraction; and strain.
The results, published in American Journal of Respiratory and Critical Care Medicine, showed significant improvements at follow-up in right ventricle end-diastolic volume index (+ 7.9 mL/m2; P = .001), as well as increases in stroke volumes (right ventricle, + 6.4 mL; P = .026; left ventricle, + 12.6 mL; P = .01).
From baseline to 8-week follow-up researchers observed higher ejection fractions (left atrium, 59.94% ± 12.23 vs. 65.45% ± 13.64; P = .013; left ventricle, 62.87% ± 7.32 vs. 66.46% ± 8.7; P = .032) and global strain measurements (left atrium, –23.55% ± 7.41 vs. –27.48% ± 6.9; P = .019; right ventricle, –22.54% ± 5.02 vs. –24.78% ± 6.01; P = .014; left ventricle, –25.85% ± 6.38 vs. –27.77 ± 6; P = .045).
Researchers also observed quality-of-life improvements, based on St. George’s Respiratory Questionnaire (–18.2 points; P < .001).
Despite increases in cardiac output (+ 0.9 L/min; P = .007) and increases in blood flow leading to higher aortic peak flow velocity, peak pressure gradient and mean pressure gradient, as well as greater arterial stiffness of the aorta, researchers did not observe changes in pulmonary artery pressures.
“We found that a reduction in hyperinflation results in improvements in cardiac preload and cardiac output, and this study shows that the enhanced cardiac preload results in improved cardiac contractility,” van der Molen said. “Therefore, these results suggest that heart failure is at least partially reversible in this patient group and elucidate the interaction between hyperinflation and cardiac function.
“Furthermore, this study assessed change in pulmonary artery pressure after BLVR in patients without pulmonary hypertension, and we showed that BLVR is not associated with a risk for pulmonary hypertension.,” van der Molen added.