Cardiac syndrome X
ICD-10 I20.9 · ICD-11 BA86

Treatment of Cardiac Syndrome X in Microvascular Angina with Reduced Coronary Flow Reserve (CFR <2.5)

This protocol applies to patients with Cardiac syndrome X presenting with microvascular angina and objective evidence of microcirculatory dysfunction — characterised by a reduced coronary flow reserve and an elevated index of microcirculatory resistance.

Clinical Scenario
  • Microvascular angina
  • Coronary flow reserve (CFR) <2.5 — indicating an abnormal microcirculatory response in non-obstructive coronary artery disease
  • Index of microcirculatory resistance (IMR) ≥25 — consistent with microvascular dysfunction
Treatment Approach (partial overview)

Antianginal therapy — including agents from the beta-blocker or calcium channel blocker class — forms the basis of first-line management in this specific presentation; the complete regimen and all combination strategies are in the full protocol.

Treatment Goals
  • Improvement in exercise time
  • Control of anginal symptoms
Instant Access to Structured Evidence-Based Regimens
References
DOI: 10.1093/eurheartj/ehae177
  • In patients with MVA and reduced CFR and/or increased IMR (which may reflect arteriolar remodelling), beta-blockers, CCBs, ranolazine, and ACE-Is are used.
  • A Doppler-derived CFR of <2.5 in non-obstructive CAD indicates an abnormal microcirculatory response corresponding to a thermodilution-derived CFR of <2.5.
  • An increased IMR (≥25) indicates microvascular dysfunction.
  • In these patients, anti-ischaemic therapy with amlodipine or ranolazine resulted in a significant improvement in exercise time.
  • First-line therapy can also be combined with ranolazine, an antianginal agent that improves myocyte relaxation and ventricular compliance by decreasing sodium and calcium overload.
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