Microvascular Vasospasm Diagnosis and Management

Diagnostic Criteria

The European Society of Cardiology recommends classifying microvascular dysfunction into two categories based on vasoreactivity testing: abnormal vasodilation (structural) and abnormal vasoconstriction (functional), with your patient having isolated abnormal vasoconstriction without structural disease 1, 2, 3
Microvascular spasm is diagnosed when acetylcholine provokes symptoms and ischemic ECG changes with <90% epicardial lumen reduction on angiography, distinguishing it from epicardial vasospasm 1, 2, 3

Adenosine is an endothelium-independent vasodilator that directly relaxes vascular smooth muscle, bypassing endothelial function, while acetylcholine is an endothelium-dependent vasodilator requiring intact endothelial function to release nitric oxide and cause vasodilation 1, 2, 4
The elevated resistance with acetylcholine compared to adenosine indicates functional rather than structural microvascular disease 1, 2

The European Society of Cardiology guidelines suggest that calcium channel blockers, particularly non-dihydropyridines like diltiazem or verapamil, are first-line therapy for microvascular vasospasm 5
Beta-blockers are absolutely contraindicated in vasospastic angina because they leave alpha-mediated vasoconstriction unopposed, potentially precipitating severe spasm 5, 6
ACE inhibitors and statins should be initiated to improve endothelial function regardless of blood pressure or lipid levels 5, 6