Background: The optimal treatment for microvascular angina (MVA) remains to be established.
Purpose and methods: The aim of study was to assess the effects of trimetazidine (TMZ) in patients with MVA. 60 symptomatic patients with MVA were randomized into 2 groups: the “TMZ” received standard medical therapy (β/calcium channel blockers, statins, antiplatelets, long-acting nitrates) and TMZ 35 mg bid for 3 months (M3), the control group (CG) received only the standard therapy. readmill test (TT), response in myocardial blood flow (MBF) and reserve of the endothelium-dependent vasodilation (REDV) to cold pressor testing (CPT) in the left anterior descending artery (LAD), left circumflex artery (LCx), and right coronary artery (RCA) assessed by 13N-ammonia positron emission tomography (PET), measurement of the reactive hyperemia index (RHI) by peripheral arterial tonometry, assessments of quality of life (QOL) and pain with the Seattle Angina Questionnaire (SAQ), measurement of circulating endothelial cells (CECs), serum endothelin-1 level (ET-1), and total antioxidant status (TOS) were carried out at baseline (M0) and after M3 of treatment.
Results: Both groups were similar at baseline. At M3, 26.7% of patients in the TMZ group and 83.3% of patients in the CG (P<0.05) had a positive TT. TMZ treatment was associated with improvements in all SAQ scores. At the M3 follow-up, 40% of patients in the TMZ group were angina-free, 33.3% had class I angina, and 26.7% had class II angina (P<0.05), while there were no significant changes in angina class in the CG. Response of MBF and REDV to CPT significantly improved in the TMZ group in all arteries compared with baseline and with the CG at M3. TMZ group M0 vs M3 (LAD MBFa CPT 86.2±29.7; REDVb -1.8 [-20.5; 17.6] vs 129.5±41.0; 49.0 [30.9; 57.8] P<0.001); (LCX MBFa CPT 93.3±30.5; REDVb -1.2 [-20.5; 17.4] vs 131.7±32.7; 40.0 [27.7; 62.7] P<0.001); (RCA MBFa CPT 91.3±30.4; REDVb -8.5 [-20.0; 17.8] vs 135.9±41.1; 39.0 [28.2; 62.4] P<0.001). CG group M0 vs M3 (LAD MBFa CPT 89.8±30.6; REDVb -2.1 [-28.6; 17.6] vs 99±32.5; -3.3 [-20.5; 16.0] P>0.05); (LCX MBFa CPT 98.6±33; REDVb 1.8 [-19.5; 19.3] vs 97.9±30; -7.4 [-15.3; 16.6] P>0.05); (RCA MBFa CPT 94.7±34.4; REDVb -8.5 [-20.0; 18.8] vs 105.2±49.6; -15.7 [-29.6; 18.5] P>0.05). aMBF value is mean ± SD, mL/100g/min; bREDV, % = (MBF CPT - MBF at rest)/MBF at rest x 100%; P-value between groups at M3 <0.01. In the TMZ group the RHI improved (1.44±0.14 at M0 vs 1.73±0.18 at M3; P<0.001), ET-1 levels decreased (2.407 [1.259; 4.689] vs 1.454 [0.850; 2.527] fmol/L; P=0.024), the number of circulating CECs decreased (17±10 cells/3x105 vs 9±5 cells/3x105 leucocytes; P<0.001), and the TOS increased (261.13±47.21 vs 323.14±115.99 μmol/L; P<0.001).
Conclusion: In patients with MVA, adding TMZ to the standard treatment improves symptoms, QOL, and exercise tolerance by improving myocardial perfusion and endothelial function.