The relationship between inspiratory muscle strength and exercise tolerance in patients with coronary heart disease.

Abstract

Background: There has been insufficient research on the assessment of exercise capacity in patients with coronary heart disease (CHD) following percutaneous coronary intervention (PCI) who exhibit inspiratory muscle weakness (IMW).

Methods: A retrospective cohort study involving CHD patients who underwent PCI at Peking University Third Hospital Heart Rehabilitation Center between January 2019 and December 2021 was conducted. Patients who had undergone inspiratory muscle testing and cardiopulmonary exercise testing (CPET) were included, and their clinical data were collected and analyzed.

Results: A total of 571 post-PCI CHD patients were included in the study. The average age was 60.8 ± 4.3 years, and 479 male patients (83.9%) were included. The average maximal inspiratory pressure (MIP) of the enrolled patients was 90.7 ± 26.1 cm H₂O, with 56 patients (9.8%) presenting with IMW. The IMW group had lower peak oxygen uptake (VO₂peak) (17.4 ± 4.2 vs. 19.3 ± 5.1 ml/min/kg, P < 0.001) and oxygen uptake efficiency slopes (OUES) (1464.7 ± 368.5 vs. 1619.2 ± 400.4, P=0.004). MIP correlated with VO₂peak (r = 0.719, P < 0.001) and OUES (r = 0.622, P < 0.001). Multivariate regression analysis revealed that VO₂peak (OR = 0.917, 95% CI = 0.858 ~ 0.980) and history of chronic obstructive pulmonary disease (COPD) (OR = 1.705, 95% CI = 0.934 ~ 3.112) were independent risk factors for IMW.

Conclusions: After PCI, CHD patients exhibiting IMW, especially those with comorbid COPD, demonstrated reduced exercise tolerance and oxygen uptake efficiency.