Refractory angina pectoris. Patient characteristics, safety and long-term effects of spinal cord stimulation

Abstract: Refractory angina pectoris has been defined as severe angina pectoris due to coronary artery disease which cannot be controlled by conventional pharmacological or surgical therapy. The epidemiology of this condition is virtually unknown. During the last decades, additional treatment options have been developed for this condition. One of these is spinal cord stimulation (SCS), which has been used for approximately 20 years as an additional symptom-relieving treatment for patients with severe angina pectoris. SCS has an anti-ischaemic effect and has been shown to be a safe and effective treatment modality. The occurrence of refractory angina pectoris among patients who had undergone coronary angiography was assessed in a defined geographic area. In order to characterise the patients with regard to concurrent diseases, treatment, functional class, quality of life, morbidity and fatality, the refractory angina patients were compared with patients with severe angina pectoris who were accepted for revascularisation. Within three years, 146 patients were identified, comprising 2.1% of all patients undergoing coronary angiography due to stable angina pectoris. The patients with refractory angina pectoris had more severe cardiac disease as well as coronary artery disease than the patients in the revascularisation group. Some of the patients in the refractory group appear to be in a fairly good condition with regard to extracardiac diseases but there is a subpopulation in the refractory group with severe cardiac as well as extracardiac diseases. The main reasons for rejection for revascularisation were unsuitable coronary anatomy and a potential risk of damaging existing grafts. After one year of follow-up the refractory patients had a higher fatality rate but a lower frequency of cerebrovascular morbidity than the revascularisation group. The refractory patients had more severe angina and lower quality of life with regard to physical function and impact of angina symptoms, compared with the revascularisation group. However, the mental health of the refractory patients was not affected compared with the revascularisation group. The patients in the so-called ESBY study (Electrical Stimulation versus Coronary Bypass Surgery in Severe Angina Pectoris, a randomised comparison of SCS and coronary artery bypass grafting (CABG) in 104 patients with severe angina pectoris and increased surgical risk) were followed up with regard to neurological and neuropsychological complications, morbidity and cost-effectiveness. There were more patients in the CABG group who developed neurological and neuropsychological complications than in the SCS group. Furthermore, presence of deep white matter disease on cerebral magnetic resonance imaging was shown to be a predictor of cerebrovascular complications after CABG. During two years of follow-up, health care costs and cardiac morbidity was lower in the SCS group than in the CABG group. However, the groups did not differ with regard to mortality or causes of death. There were no serious complications related to the SCS treatment. CONCLUSION Refractory angina pectoris appears to be a considerable problem. This patient group has a high fatality rate and low quality of life compared with revascularised patients. SCS, which is one of the recommended treatment option for these patients, was found to be safe (in terms of mortality, morbidity and absence of serious complications) and effective (in terms of symptom relief and cost-effectiveness) during long-term treatment. Furthermore, presence of deep white matter disease on cerebral magnetic resonance imaging seems to be a predictor of cerebrovascular complications after CABG.