Impaired peripheral microvascular reactivity in patients with nonobstructive coronary artery disease

OBJECTIVE: This study aimed to determine whether peripheral microvascular reactivity is impaired in patients with nonobstructive coronary artery disease (NOCAD).

METHODS: Stable patients presenting with angina were recruited and, based on results from coronary angiography, were categorized into OCAD (coronary stenosis of ≥50%) and NOCAD (stenosis <50%) groups. A control group with no history of angina was also recruited. Forearm skin microvascular reactivity was measured using the laser Doppler blood perfusion monitor and the process of postocclusive skin reactive hyperemia (PORH).

RESULTS: Patients were categorized into OCAD (n = 42), NOCAD (n = 40), and control (n = 39) groups. Compared with the control group, the PORH perfusion percent change (PORH% change) was significantly lower in the OCAD and NOCAD groups. No significant differences were noted between the OCAD and NOCAD groups. Additionally, the NOCAD group without any coronary obstruction takes a longer time to reach peak perfusion and had lower PORH% change compared with the nonangina control group.

CONCLUSION: Angina patients with NOCAD have microvascular dysfunction as demonstrated by reduced magnitude of reperfusion with an ischemic stimulus. NOCAD patients without coronary obstruction also displayed a slower response to reperfusion.