A randomized, triple-blind trial of cardiac shock-wave therapy on exercise tolerance and symptoms in patients with stable angina pectoris

Background Despite major advances in managing coronary artery disease and continuous research on alternative techniques to enhance myocardial perfusion and reduce symptoms, coronary artery disease is still one of the leading causes of adult disability worldwide. Cardiac shock-wave therapy (CSWT) has shown promising results in the amelioration of myocardial ischemia in experimental studies; however, clinical results are limited to single-center, mostly uncontrolled and underpowered trials. The current study aimed to evaluate whether CSWT can improve exercise tolerance and relieve angina symptoms in addition to optimal medical treatment in patients with stable angina. Participants and methods A prospective, randomized, triple blind, sham-procedure-controlled study was carried out. The primary endpoint was total exercise duration in the modified Bruce treadmill test at the 6-month follow-up. The secondary endpoints were changes in ST-segment depression during the treadmill test, angina symptoms during the treadmill test, number of angina attacks per week, number of sublingual nitroglycerin consumption per week, Canadian Cardiovascular Society angina functional class, and the Seattle Angina Questionnaire score at the 6-month follow-up. Patients were randomized at a 1 : 1 ratio to optimal medical plus cardiac shock-wave therapy (OMT+CSWT) and optimal medical therapy with sham procedure (OMT+placebo) groups. Results The mean exercise time improved in both study arms – CSWT and placebo treatment – at the 3- and 6-month follow-up, without a significant difference between groups. The magnitude and frequency of peak exercise ST-segment depression reduced significantly in the CSWT+OMT group compared with the OMT+placebo group at the 6-month follow-up (51.4 vs. 90.6%, P=0.001). Percentage of angina-free patients increased progressively in both groups throughout the study. The Seattle Angina Questionnaire scores improved significantly in both arms for four of five domains at the 3- and the 6-month follow-up. Numerically, although insignificant, the decrease in the number of angina episodes was more prominent in the OMT+CSWT group compared with the OMT+placebo group. Conclusion The total exercise duration in the modified Bruce treadmill test at the 6-month follow-up did not differ significantly in patients treated with CSWT compared with optimal medical therapy alone. In addition, CSWT exerted a neutral effect on the quality of life and level of angina.