Hyperventilation combined with exercise stress echocardiography identified microvascular dysfunction and inadequate coronary flow reserve in a patient with CMD.
Does combined hyperventilation and exercise stress echocardiography, along with CMR, effectively detect coronary microvascular dysfunction in a patient with ANOCA?
Hyperventilation stress echocardiography combined with CMR is a practical and effective non-invasive diagnostic approach for detecting coronary microvascular dysfunction in patients with ANOCA when invasive testing is not performed.
Introduction: Coronary microvascular dysfunction (CMD) causes angina in patients with non-obstructive coronary arteries (ANOCA) due to structural and functional microcirculation abnormalities. Although invasive testing is the gold standard, its use is limited. Non-invasive methods like hyperventilation combined with exercise stress echocardiography offer practical, accessible assessment of coronary vasomotor function and CMD detection. Case report: We present a case of a 55-year-old woman with longstanding exertional chest pain, fatigue, and dyspnea, who remained undiagnosed despite normal findings on coronary CT and invasive angiography. Invasive testing with acetylcholine was not performed. Due to persistent symptoms, she underwent non-invasive evaluation using a combined hyperventilation and exercise stress echocardiography protocol. The test revealed a drop in coronary flow velocity after hyperventilation and inadequate coronary flow velocity reserve (CFVR 2) at peak exercise, with accompanying ST depression and subtle wall motion abnormalities-indicative of microvascular vasospasm. Cardiac magnetic resonance imaging (CMR) using adenosine and hyperventilation protocols confirmed widespread subendocardial perfusion defects, supporting a diagnosis of mixed-type CMD with both functional and structural components. Treatment with a calcium channel blocker, ranolazine, and statin led to marked symptom improvement. Conclusion: This case highlights the diagnostic value of non-invasive methods-particularly hyperventilation stress echocardiographic test, further confirmed by CMR.
Dedić et al. (2025) studied this question. Hyperventilation combined with exercise stress echocardiography identified microvascular dysfunction and inadequate coronary flow reserve in a patient with CMD.