Shock-Wave Therapy Improves Myocardial Blood Flow Reserve in Patients with Refractory Angina: Evaluation by Real-Time Myocardial Perfusion Echocardiography.

BACKGROUND: Cardiac shock-wave therapy (CSWT) has been demonstrated as an option for the treatment of patients with refractory angina (RA), promoting immediate vasodilatory effects and, in the long-term, neoangiogenic effects that would be responsible for reducing the myocardial ischemic load. The aim of this study was to determine the effects of CSWT on myocardial blood flow reserve (MBFR) assessed by quantitative real-time myocardial perfusion echocardiography in patients with RA. METHODS: Fifteen patients (mean age 61.5 ± 12.8 years) with RA who underwent CSWT during nine sessions, over 3 months of treatment, were prospectively studied. A total of 32 myocardial segments with ischemia were treated, while another 31 did not receive therapy because of technical limitations. Myocardial perfusion was evaluated at rest and after dipyridamole stress (0.84 mg/kg) before and 6 months after CSWT, using quantitative real-time myocardial perfusion echocardiography. Clinical effects were evaluated using Canadian Cardiovascular Society grading of angina and the Seattle Angina Questionnaire. RESULTS: The ischemic segments treated with CSWT had increased MBFR (from 1.33 ± 0.22 to 1.74 ± 0.29, P < .001), a benefit that was not observed in untreated ischemic segments (1.51 ± 0.29 vs 1.54 ± 0.28, P = .47). Patients demonstrated increased global MBFR (from 1.78 ± 0.54 to 1.89 ± 0.49, P = .017). Semiquantitative single-photon emission computed tomographic analysis of the treated ischemic segments revealed a score reduction from 2.10 ± 0.87 to 1.68 ± 1.19 (P = .024). There was improvement in Canadian Cardiovascular Society score (from 3.20 ± 0.56 to 1.93 ± 0.70, P < .05) and in Seattle Angina Questionnaire score (from 42.3 ± 12.99 to 71.2 ± 14.29, P < .05). No major cardiovascular events were recorded during follow-up. CONCLUSIONS: CSWT improved MBFR in ischemic segments, as demonstrated by quantitative real-time myocardial perfusion echocardiography. These results suggest that CSWT has the potential to increase myocardial blood flow, with an impact on symptoms and quality of life in patients with RA.