Impact of Coronary Microvascular Dysfunction on Myocardial Strain in Patients with Heart Failure and Preserved Ejection Fraction.

Background: This research aimed to evaluate the role of coronary microvascular dysfunction in alteration of left ventricular (LV) myocardial deformation.

Materials and methods: This observational study involved 50 patients with LV ejection fraction (LVEF) >50% and coronary microvascular dysfunction (diagnosed by coronary angiography). TIMI frame count (TFC) was calculated for each patient. They were classified into 2 groups: 30 patients with heart failure and preserved ejection fraction (HFpEF) (cases group) and 20 patients without HF (control group). Speckle tracking echocardiography was used to evaluate LV deformation.

Results: The mean age of the studied patients was 58.8 ± 8 years. The frequency of diabetes mellitus, hypertension, and dyslipidemia were significantly higher in cases than controls. Cases had significant higher BMI (30 ± 4.48 vs. 27.3 ± 3.94 kg/m², P=0.029). The total TFC in cases was 97.1 ± 22.9 and in controls was 79 ± 18.5, and this difference was statistically significant (P=0.005). Significantly decreased LV global strain was observed in HFpEF cases than in controls (-17.6 ± 2.14 % versus -19.5 ± 1.98%, P < 0.001). In cases with a higher TFC, the LV global strain decrease was more pronounced. There was a significant correlation between the LV global strain and total TFC (r=-0.470 and P=0.009).

Conclusion: Patients with HFpEF exhibited higher total TFC reflecting more affected coronary microvasculature. Those patients had reduced LV global strain. Coronary microvascular dysfunction probably leads to alteration of myocardial performance.