The Role of Aortic Stiffness Parameters in Evaluating Myocardial Ischemia

BACKGROUND: Arterial stiffness is a process resulting in deterioration of hemodynamic function of the aorta, a decrease in its compliance and elasticity, caused by the proportional change of components of the extracellular matrix. Although many researches have been done to determine the etiologies of myocardial ischemia in the absence of obstructive coronary artery disease, none of them has investigated the relation between the parameters of aortic stiffness and the myocardial ischemia documented by the exercise stress test. The present cross-sectional study aimed to investigate the difference of aortic stiffness parameters between the groups separated by exercise stress test result as positive and negative ischemic findings in the absence of obstructive coronary artery disease. METHODS: The present study included 79 patients who were admitted to Istanbul Faculty of Medicine, Department of Cardiology with complaint of chest pain. Forty patients (21 women and 19 men) have ischemic findings on the exercise electrocardiography (ECG) test and 39 patients (20 women and 19 men) have normal exercise ECG results. The patients who have positive exercise ECG findings underwent coronary angiography and all the patients had non-obstructive coronary artery disease. Demographic features (age, sex and comorbidities) were statistically similar between the groups. Aortic stiffness measurements (pulse wave velocity, pulse pressure, aortic augmented pressure, augmentation index, systolic pressure-time index, diastolic pressure-time index and subendocardial viability ratio) were done with tonometric methods. RESULTS: There was no significant difference between the two groups in terms of the aortic stiffness parameters. Systolic blood pressure (P = 0.33), diastolic blood pressure (P = 0.24), pulse pressure (P = 0.60), systolic pressure-time index (P = 0.10), diastolic pressure-time index (P = 0.91), subendocardial viability ratio (P = 0.19), aortic augmented pressure (P = 0.87), augmentation index (P = 0.58) and pulse wave velocity (P = 0.56) were detected between the two groups. Biochemical parameters were found similar between the two groups. Only low-density lipoprotein levels were slightly higher in patients with negative exercise stress test result (139 vs. 123 mg/dL, P = 0.02). CONCLUSION: There is no finding supporting that the aortic stiffness identifies the patients with non-obstructive coronary artery disease but with signs of myocardial ischemia and further investigation of other causes of myocardial ischemia is required.