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Coronary sinus Reducer implantation results in improved oxygen kinetics at cardiopulmonary exercise test in patients with refractory angina.

AIMS
Refractory angina is still a major public health problem. The Coronary Sinus Reducer (CSR) has recently been introduced as an alternative treatment to reduce symptoms in these patients. Aim of this study is to investigate objective improvements in effort tolerance and oxygen kinetics as assessed by cardiopulmonary exercise testing (CPET) in patients suffering from refractory angina undergoing CSR implantation.


METHODS AND RESULTS
In this multicentre prospective study, patients with chronic refractory angina undergoing CSR implantation were scheduled for CPET before the index procedure and at 6-month follow-up. Main endpoints of this analysis were improvements in VO 2 max and in VO 2 at anaerobic threshold (AT). Clinical events and improvements in symptoms were also recorded. A total of 37 patients formed the study population. CSR implantation procedure was successful and without complications in all. At follow-up CPET significant improvement in VO 2 max (+0.97 ml/kg/min [+11.3%], 12.2±3.6 ml/kg/min at baseline vs 13.2±3.7 ml/kg/min, p=0.026), and workload (+12.9[+34%]; 68±28 W vs 81±49W, p=0.05) were observed, with non-significant differences in VO 2 at AT (9.84±3.4 ml/kg/min vs 10.74±3.05 ml/kg/min, p=0.06). Canadian Cardiovascular Society (CCS) grade improved from a mean of 3.2±0.5 to 1.6±0.8 (p<0.01), and significant benefits in all Seattle Angina Questionnaire variables were shown.


CONCLUSIONS
In patients with obstructive coronary artery disease suffering from refractory angina, the implantation of CSR was associated with objective improvement in exercise capacity and oxygen kinetics at CPET, suggesting a possible reduction of myocardial ischemia.