A Safety And Efficiency Evaluation And Methodological Outline Of Extracorporeal Cardiac Shock Wave Therapy(CSWT) For Treatment Of Coronary Artery Disease

Coronary artery disease (CAD) is recognized as a leading cause of adult mortality worldwide. Current therapies in the treatment of CAD include drug interventions, percutaneous coronary intervention (PCI), coronary artery bypass graft (CABG) and transmyocardial laser revascularization (TMR). However, these approaches are invasive and often inadequate in the treatment of advanced CAD and are associated with serious cardiovascular risks and complications. Elevated patient risk factors including increased age and co-morbidities such as hypertension and diabetes may further limit treatment options. Prognosis for patients diagnosed with end stage CAD without indication of PCI or CABG surgery is poor. Thus, it is critical to note that a large number of CAD patients continue to experience angina, decreased exercise tolerance and the risk of sudden death. Understandably, there is need for a safe and effective, noninvasive approach toward the treatment of CAD. Cardiac shock wave therapy (CSWT) is a novel, noninvasive intervention that can ameliorate myocardial ischemia and improve cardiac function. To further investigate the potential benefits of CSWT we performed a preliminary study of CSWT administered regularly over a 12 month period in 41 patients with advanced CAD. Patients were clinically assessed before initiation and at 3 month,6 month and 12 month following completion of the CSWT treatment program.Purpose. To evaluate the feasibility and efficiency of CSWT for treatment of CAD and to establish the inclusion and exclusion criteria and summarize the methodological outlines of CSWT in China. Methods. Fifty-five patients with 1-16 years history of chronic angina pectoris admitted to the Cardiology Department from August 2008 to December 2009 were enrolled in this study. All patients received standard medical treatment and the CSWT procedure was explained to each patient. Patients were divided group A and group B. twenty patients in group A,18 males, ranged from 55-70 years were applied 9 sessions on 35 segments within 3 month. Twenty-one patients in group B,17 males, ranged from 41-79 years were applied 9 sessions on 35 segments within 1 month. Fourteen patients in group C,12 males, ranged from 55-81 years were enrolled as medical-controlled group. The reasons for hospitalization included repeated episodes of chest tightness, shortness of breath, and fatigue after PCI/CABG. Exclusion criteria were absence of the inclusion criteria, acute myocardial infarction (AMI) with 1 month, uncontrolled heart failure, severe chronic obstructive pulmonary disease. Prior to initiation of CSWT, all patients received Dobutamine stress echocardiography (DSE) and 99mTc-MIBI myocardial perfusion imaging(MPI) at rest and stress state to identify areas of ischemic myocardium. Treadmill and Holter were performed to assess the exercise tolerance and ischemic threshold. Under the guidance of echocardiography, we applied shock wave in R-wave-triggered manner with low energy(0.09mJ/mm2) at 200 shoots/spot for 9 spots (-l--0-+1 combination). During the procedure, ECG, blood pressure, breathing, and blood oxygen saturation were concurrently monitored and vital signs and symptoms including palpitations, chest pain, breathing difficulty, and dizziness were closely inquired. We followed-up all patients at 3 month,6 month and 12 month after 1st time therapy and enzyme markers of myocardial, liver and renal injury were measured prior to CSWT and at 3 times,9 times following completion of CSWT. The efficacy of CSWT was assessed using the Canada Cardiovascular Society (CCS) angina scale, NYHA class, SAQ scale (angina),6-min walk test (6MWT) and nitroglycerin dose. Myocardial perfusion, regional myocardium function and wall motion were evaluated by MPI, peak systolic strain rate (PSSR) and M-mode measure at rest and Dob stress state. The left ventricular ejection fraction (LVEF), end-diastolic volume (EDV)and end-systolic volume(ESV) were measured by Simpson method.Results. A total of 94 viable ischemic myocardial segments were identified by stress MPI and SE。Forty-one patients with 70 ischemic segments underwent the CSWT without procedural complications or adverse effects. Patients did not experience any serious cardiovascular health complications (heart failure, bleeding, thrombosis, shock or death) either during or after CSWT. At 6 month follow-up, one died because of serious heart failure not related to CSWT and two CABG patients received the stent implantation because of refractory angina pectoris. There was ECG changing from T wave inversion to positive T wave after 3 times CSWT and stay the course of 12 month. Plasma levels of enzyme markers had no significant difference before and after CSWT. CSWT significantly improved symptoms, as evaluated by NYHA, CCS class score, SAQ score,6MWT and the use of nitroglycerin. Also, CSWT improved myocardial perfusion and regional myocardium function as evaluated by MPI and PSSR both at rest and stress. 65.71% segments have a mild improvement in MPI of 70 ischemic segments. The exercise tolerance and ischemic threshold were increased significantly measured by treadmill and Holter. There was a evident decrease in the number of ventricular premature in group A and the number of atrial premature in group B. Whereas, group C had little difference, even had a malignant tendency in EDV and ESV following 3,6 and 12 month. And many indicators improved preferably and lasted longer in group A compared with group B.Conclusions.1. We provide scientific basis of CSWT for the first time in China.2. CSWT is a safe and effective non-invasive intervention in the management of patients with CAD.3. Indications and contraindications of CSWT in China are concluded, not only for refractory CAD, but also for those chronic pectoris which are reluctant or have no condition to undergo the invasive therapy.4. DSE combined with MPI is a preferable method to locate the viable ischemic myocardial segments and guarantees the accuracy and effect of CSWT.5.9 sessions CSWT within 3 month have an advantage over the same times within 1 month. Maybe the expanded treatment areas like 20-40 spots each time can make better results. Unless there is an ischemic evidence, it is no need to repeat CSWT frequently.