Coronary Sinus Reducing Stent for the Treatment of Refractory Angina Pectoris: A Health Technology Assessment

AIM: To summarize the evidence on the clinical effectiveness and safety of coronary sinus reducing stent (CSRS) therapy in refractory angina pectoris (AP) patients. METHODS: We performed a systematic literature search in common databases (n=4). The evidence obtained was summarized according to GRADE methodology. A health technology assessment (HTA) was conducted using the HTA Core Model(®) for Rapid Relative Effectiveness Assessment. Primary outcomes for the clinical effectiveness domain were the proportion of patients with improvement in two or more Canadian Cardiovascular Society (CCS) angina score classes, overall mean reduction of CCS class, and Seattle Angina Questionnaire (SAQ) quality of life (QoL) score improvement. Outcomes for the safety domain were adverse device effects (ADEs) and serious adverse device effects (SADEs). RESULTS: One randomized controlled trial (RCT) was identified. Outcomes that showed statistically significant differences between CSRS and sham treatment (in favor of CSRS) were CCS angina score improvement of one or two classes, overall mean reduction of CCS class, and SAQ QoL score improvement. Concerning safety, the sham-controlled trial data indicate that there were fewer SADEs in the intervention group (19%) than in the control group (46%). SADEs reported in observation studies ranged from none to 30%. The most frequently reported SADEs were death and stable angina. In the RCT, the only case of death occurred in the control group. Concerning clinical effectiveness, the risk of bias (RoB) was rated to be low, and concerning safety, the RoB was rated to range from low to moderate. As assessed by GRADE, the overall strength of evidence for effectiveness and safety was moderate. Internal and external validity of the evidence base were low. CONCLUSION: Even though the current evidence indicates that the assessed technology, CSRS, is potentially more effective than sham intervention for refractory AP patients, the lack of internal validity of the studies undermines the partially positive results.