1000 Section - Prospective Study on Changes in Maximal Inspiratory Pressure (MIP) Following a Cardiac Rehabilitation Program in a Cohort of Spanish Patients

Objectives : The primary objective of this study was to evaluate changes in maximal inspiratory pressure (MIP) in patients participating in a cardiac rehabilitation (CR) program at a tertiary care center. Secondary objectives included: (1) determining the relationship between MIP improvement and changes in functional capacity assessed by ergometry; (2) examining the association between MIP variation and dyspnea severity; (3) analyzing the influence of adherence to CR on respiratory muscle outcomes; and (4) exploring correlations between MIP changes and body composition parameters obtained through bioimpedance analysis. An additional objective was to assess whether MIP could serve as a complementary functional biomarker within CR monitoring.

Design: This prospective observational study included adults ( >18 years) referred to the CR program at Hospital General Universitario Gregorio Marañón. Exclusion criteria were cognitive impairment, language barriers, or previous respiratory rehabilitation. MIP was measured at baseline and at program completion, and compared against predicted values using the Black–Hyatt equation. Additional variables collected included dyspnea (mMRC), exercise capacity (ergometry), anthropometrics, body composition by bioimpedance, and program adherence.

Results: Up to 160 patients were eligible for inclusion. Preliminary findings show a significant increase in MIP following CR, with improvements frequently reaching the predefined threshold for clinical relevance. MIP gains were positively associated with enhanced exercise performance and decreased dyspnea scores. Patients demonstrating higher program adherence and presenting lower baseline cardiovascular risk exhibited the greatest respiratory muscle strength improvements. No major adverse events related to inspiratory assessments were observed.

Conclusion: CR appears to produce meaningful improvements in inspiratory muscle strength, as reflected by significant increases in MIP. These changes correlate with functional and symptomatic benefits, suggesting that MIP could serve as a valuable complementary biomarker within CR evaluation protocols. Systematic incorporation of respiratory muscle assessment may contribute to more comprehensive patient profiling and optimized rehabilitation planning.