Abstract
Background: With modern diagnostic tools, incidence ischemia with no obstructive coronary atherosclerosis (INOCA) and heart failure with preserved ejection fraction (HFpEF) are found to be much higher than previously believed, and-as they lead to adverse cardiovascular outcomes-their causes and development are subjects of ongoing research. There is growing evidence that coronary microvascular dysfunction might be the underlying cause of both INOCA and HFpEF. Methods: In 65 patients with effort angina but no obstructive coronary artery disease, the index of microvascular resistance and coronary flow reserve were measured invasively in the LAD. The echocardiographic parameters, including left atrial strain, left ventricular strain, and indices of left ventricular diastolic dysfunction, were compared between two groups of patients: those with normal coronary microcirculation parameters and those with impaired coronary microvascular function. Results: Patients with coronary microvascular dysfunction had higher a E/E' index than those with normal microvessel reactivity. This finding was further confirmed by ROC analysis. The groups did not differ significantly in values of other echocardiographic parameters, including the left ventricular and left atrial strain. The prevalence of classical cardiovascular risk factors was similar in both groups. Conclusions: The coexistence of impaired coronary microvascular function with moderately elevated left ventricular filling pressures might correspond to the co-development of early stages of coronary microvascular dysfunction and HFpEF.