Initial and long-term effects of enhanced external counterpulsation in patients with refractory angina pectoris

Abstract: Symptom relief through spinal cord stimulation (SCS) based on the gate-control theory and enhanced external counterpulsation (EECP) through improved coronary perfusion is two treatments in angina pectoris refractory to medication and surgery. The overall aim was to evaluate and compare the initial and longterm effects, utilization and cost of EECP compared to SCS. The effects were also compared to the effects of retained medical treatment in groups of controls and age-matched healthy people. Study I included 153 consecutive patients treated with either SCS, EECP or retained pharmacy. The anginal status was registered by Canadian Cardiovascular Society (CCS) class and weekly sublingual glyceryl trinitrate (GTN) use at baseline, 6 and 12 months after treatment. Study II comprised 153 consecutive patients receiving EECP or not. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP) and heart rate were measured at baseline, post-EECP and at a 12 month follow-up. Study III included data from 73 patients drawn from the PASiS, a register of healthcare consumption and costs. Data were merged with CCS class following SCS and EECP respectively. Study IV comprised 20 patients randomized to EECP or not. Laser Doppler with iontophoresis, hemodynamics and blood samples were used to collect data concerning cutaneous microcirculation. The data were compared to 20 age-matched healthy controls. CCS class decreased after SCS and EECP compared to medically treated controls. EECP was slightly better than SCS. Thus EECP can be used as an alternative treatment for patients who do not responde to electrical stimulation. Both treatments lowered GTN compared to the controls. EECP altered the blood pressure. A decrease was more common than in the controls, where an increase was more common. EECP patients with decreased blood pressure had a higher baseline MAP, SBP and DBP compared to those increasing. Blood pressure responses did not persist at the follow-up. Acute hospitalisations and costs for patients undergoing SCS and EECP decreased in the first and second years of follow-up respectively. EECP showed an association between hospital admissions and improved CCS class. Reduced responsiveness in the refractory angina patient’s cutaneous microcirculation to acetylcholine, sodium nitroprusside and to heat was seen as compared to healthy controls. Although EECP reduced the CCS class this was not associated with an improvement in responsiveness of the cutaneous microcirculation. EECP corresponded positively in reducing the plasma level of sIL-2 receptor as a marker of inflammatory activity. This reduction was paralleled by decreases in CCS class.