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Correlation between coronary microvascular dysfunction and cardiorespiratory fitness in patients with ST-segment
Jinglin Li1, Wei Zhao1,2,3,4, Zhenyu Tian1
1Department of Cardiology and Institute of Vascular Medicine, Peking University Third Hospital, Beijing, 100191, China.
Insights
Cardiopulmonary exercise testing (CPET) reveals significant myocardial ischemia in patients with coronary microvascular dysfunction (CMD) after ST-elevation myocardial infarction (STEMI). Elevated microcirculatory resistance (AccuIMR) independently predicts reduced exercise capacity and ECG changes.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Coronary microvascular dysfunction (CMD) is increasingly recognized in ST-elevation myocardial infarction (STEMI) patients.
- Assessing CMD noninvasively after primary percutaneous coronary intervention (PCI) is crucial for understanding long-term outcomes.
Purpose of the Study:
- To investigate the relationship between cardiopulmonary exercise testing (CPET) parameters and coronary microvascular dysfunction (CMD).
- To evaluate the utility of a novel angiography-based index of microcirculatory resistance (AccuIMR) in identifying CMD post-STEMI.
Main Methods:
- Retrospective analysis of 418 STEMI patients who underwent primary PCI with complete revascularization.
- Calculation of culprit vessel AccuIMR post-PCI and subsequent CPET.
- Correlation and multivariable logistic regression analyses to assess relationships between AccuIMR, CPET parameters, and ischemia indicators.
Main Results:
- 157 patients (37.6%) exhibited elevated AccuIMR, indicating CMD.
- Patients with CMD (elevated AccuIMR) had significantly lower LVEF, VO2peak, and peak O2-pulse, and a worse VE/VCO2 slope compared to the Non-CMD group.
- AccuIMR was an independent predictor of reduced VO2peak, elevated VE/VCO2 slope, and noninvasively detectable myocardial ischemia indicators like positive ECG results and early O2-pulse flattening.
Conclusions:
- Elevated AccuIMR post-STEMI is associated with impaired exercise capacity and noninvasively detectable myocardial ischemia.
- CPET parameters, particularly VO2peak and VE/VCO2 slope, are significantly correlated with AccuIMR.
- AccuIMR serves as an independent predictor of myocardial ischemia in STEMI patients, highlighting the importance of assessing microvascular function.
Abstract:
We retrospectively investigated the relationship between cardiopulmonary exercise testing (CPET) parameters and coronary microvascular dysfunction (CMD) using a novel angiography-based index of microcirculatory resistance (AccuIMR) in patients with ST-elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI) with complete revascularization. In 418 patients, the culprit vessel AccuIMR was calculated after successful primary PCI. CPET was conducted 44.04 ± 19.28 days after primary PCI. Overall, 157 patients (37.6%) showed elevated AccuIMR (> 40 U) in the culprit vessels. The LVEF was significantly lower in the CMD group than in the Non-CMD group. The CMD group showed worse results in VO2peak, peak O2-pulse, and VE/VCO2 slope than the Non-CMD group. Spearman correlation analysis suggested that VO2peak (r = -0.354), peak O2-pulse (r = -0.385) and VE/VCO2 slope (r = 0.294) had significant linear correlations with AccuIMR (P < 0.001). Multivariable logistic regression analysis showed that AccuIMR was the independent predictor of reduced VO2peak and elevated VE/VCO2 slope. The proportions of positive and equivocal ECG results and early O2-pulse flattening in the CMD group were significantly higher than those in the Non-CMD group, and AccuIMR was the only independent predictor of these ischemia-relating indicators, suggesting that patients with CMD had significant noninvasively detectable myocardial ischemia.
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