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Index of microcirculatory resistance predicts long term cardiac systolic function in patients with STEMI undergoing
1Department of Cardiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, 210008, China.
Background:
To evaluate the predictive value of the index of microcirculatory resistance (IMR) for long-term cardiac systolic function after primary percutaneous coronary intervention (pPCI) in patients with acute anterior wall ST-segment elevation myocardial infarction (STEMI).
Methods:
A total of 53 acute anterior wall STEMI patients were included and followed up within 1-year. IMR was measured to evaluate the immediate intraoperative reperfusion. IMR > 40 U was defined as the high IMR group and ≤ 40 U was defined as the low IMR group. Left ventricular ejection fraction (LVEF) was measured by echocardiography at 24 h, 1 month, 3 months, and 1 year after PCI to analyze the correlation between IMR and cardiac systolic function. Heart failure was estimated according to classification within one year.
Results:
The ratio of TMPG (TIMI myocardial perfusion grade) 3 (85.7% vs. 52%, p = 0.015) and STR (ST-segment resolution) > 70% (82.1% vs. 48%, p = 0.019) were significantly higher in the low IMR group. The LVEF in the low IMR group was significantly higher than that in the high IMR group at 3 months (43.06 ± 2.63% vs. 40.20 ± 2.67%, p < 0.001) and 1 year (44.16 ± 2.40% vs. 40.13 ± 3.48%, p < 0.001). IMR was negatively correlated with LVEF at 3 months (r = - 0.1014, p = 0.0040) and 1 year (r = - 0.1754, p < 0.0001).
Conclusions:
The IMR showed significant negative correlation with the LVEF value after primary PCI. The high IMR is a strong predictor of heart failure within 1 year after anterior myocardial infarction.
