Management of Coronary Microvascular Dysfunction

Guideline-Based Treatment Algorithm

The European Society of Cardiology recommends adding ranolazine to a patient's current regimen of nebivolol and amlodipine for coronary microvascular dysfunction, particularly in cases of inadequate symptom control on dual first-line therapy 1, 2
The combination of a beta-blocker with a dihydropyridine CCB like amlodipine is specifically recommended as appropriate for most patients with chronic coronary syndromes 1
The 2024 ESC guidelines provide a Class IIa, Level B recommendation that "long-acting nitrates or ranolazine should be considered as add-on therapy in patients with inadequate control of symptoms while on treatment with beta-blockers and/or CCBs" 1, 2

Ranolazine works through a unique mechanism—inhibiting the late inward sodium current—which reduces intracellular calcium overload during ischemia without affecting heart rate or blood pressure 4, 5
Ranolazine and trimetazidine are specifically recommended for patients with microvascular angina according to the ESC guidelines 1

Ranolazine prolongs the QTc interval in a dose-dependent manner, and a baseline ECG should be obtained before starting ranolazine 4
Common side effects of ranolazine include constipation, nausea, dizziness, and headache, which are generally mild and do not require discontinuation 4

Ranolazine is purely a symptomatic therapy and does not improve cardiovascular outcomes (mortality or MI), as shown in the MERLIN-TIMI 36 trial of 6,560 patients with NSTE-ACS 4, 5

Long-acting nitrates (isosorbide mononitrate) are an equally valid Class IIa recommendation for add-on therapy in cases where ranolazine fails to adequately control symptoms 1, 2
Trimetazidine (Class IIb recommendation) may be considered, particularly if the patient develops hypotension, as it has no hemodynamic effects 1, 6