Increased arterial stiffness in patients with ischemia and no obstructive coronary artery disease

Abstract

Abstract Introduction Recent studies have shown that patients with angina pectoris and no obstructive coronary artery disease are a heterogeneous population with an elevated risk of major adverse cardiovascular events. The current literature lacks evidence regarding the possible association between arterial stiffness and coronary microvascular dysfunction (CMD). Purpose The aim of this study is to determine whether arterial stiffness is increased among patients with CMD compared to hypertensive control group. Methods We examined 25 patients [10 female, 40%, mean age: 60.7±9.6 years, mean office blood pressure (BP) : 141/88±17/9 mmHg] and 35 CMD patients (22 female, 63%, mean age : 62.4±4.9 years, average office BP: 129/79±15/10 mmHg). In the group of patients with chronic angina, CMD was defined by a standardized systematic protocol in which coronary flow reserve (CFR) and index of microvascular resistance (IMR) were measured in the left anterior descending coronary artery using a temperature/pressure sensor-tipped guidewire. In addition, in all participants, arterial stiffness was assessed using aortic augmentation index (AIx), derived from the analysis of central pulse waveforms, recorded by applanation tonometry directly from the radial artery. Results In the CMD group, mean CFR and IMR were 1.3±0.9 and 45.7±35, respectively. Out of the 35 CMD patients with abnormal CFR 12 of them (34%) had a normal value of IMR, indicating functional microvascular dysfunction. On the other hand, 23 patients (66%) had an abnormal IMR, indicating structural microvascular dysfunction. In CMD group compared to asymptomatic controls, AIx was found significantly higher (35.6±10.5 vs 25.1±12.1%, p=0.03). This difference in AIx between groups was found to be statistically significant after adjustment for age, gender and levels of BP (p<0.05). Moreover, no significant differences were found in body mass index, renal function, history of dyslipidemia, diabetes mellitus and smoking status between the two groups (p=NS for all). Conclusion CMD patients are characterized by increased arterial stiffness in comparison with asymptomatic controls, independently of demographic and hemodynamic confounders. These results indicate that impairment of the microvasculature is associated with large artery stiffening. Thus, potential clinical benefit could be derived from specific therapies targeting AIx in patients with CMD.