Table 2

Therapeutic studies in patients with syndrome X or INOCA and those with confirmed CMD

Drug classSyndrome X/INOCA populationCMD population
First-line antianginal agents
 Beta blocker Randomised double-blind crossover studies—reduced angina, less ST depression episodes, improved markers of endothelial function 41 Not tested in this population
 Calcium channel blockers Reduced angina, increased exercise time 42 Only single dose of intravenous diltiazem tested did not improve CFR immediately43
 Nitrates Reduced ischaemic threshold to exercise or rapid pacing 44 Not tested in this population
Second-line antianginal agents
 NicorandilNot tested Increased ischaemic threshold (using CFR <3.0 as CMD inclusion) 45
 RanolazineContradictory, improved or unchanged symptoms46 Improved symptoms and reduced coronary microvascular resistance measured invasively (using CFR<2.5 or IMR>20 U as CMD inclusion) 47
Disease-modifying agents
 ACE inhibitors Increased exercise duration, ischaemic threshold, endothelial function and CFR 48 Improved CFR at 16 weeks (using CFR<3.0 as CMD inclusion) 49
 Statins Improved symptoms, exercise tolerance and endothelial function 50 Improved coronary ACh CFR after 6 months treatment (using ACh CFR <1.5 as CMD inclusion) 32
  • Green text emphasises improvement with medication and red text emphasises deterioration with medication.

  • CFR, coronary flow reserve; CMD, coronary microvascular dysfunction; INOCA, ischaemia with no obstructive coronary arteries.