A first-in-man study of percutaneous myocardial cryotreatment in nonrevascularizable patients with refractory angina

To evaluate the safety and feasibility of myocardial cryotreatment for patients with coronary artery disease (CAD) and severe angina refractory to standard treatment.

Innovative myocardial revascularization strategies are needed for patients with CAD and severe angina uncontrolled by conventional methods. Preclinical data have demonstrated that cryotherapy can induce myocardial neovascularization through arteriogenesis.

This was a two center, nonrandomized, study that enrolled 20 patients. All patients had CAD and severe angina (CCS Angina Class III or IV). Safety was the primary endpoint. Treatment involved 8-10 intramyocardial cryoapplications (at < or = -50 degrees C), for 2 min by a specially designed percutaneous catheter at an identified ischemic area of the myocardium. Primary endpoint was safety, with secondary endpoints of angina severity, exercise tolerance, quality of life, and myocardial perfusion assessed by radionuclide scintigraphy.

The procedure was successful in 19 patients. There were three device-related events, a pericardial tamponade requiring pericardiocenetesis, a clinically nonsignificant pericardial effusion, and an episode of ventricular tachycardia requiring cardioversion in one patient. Complete 12-month follow-up was obtained in 16 patients. Significant reduction in CCS angina scores and significant improvements in both exercise tolerance and quality of life (P < 0.05) were seen at 6 and 12-month follow-up. Although no significant differences were observed in myocardial perfusion in the overall group, marked improvement was detected in 8 (42%) patients.

Cryotreatment is feasible and safe in patients with severe angina refractory to standard management. Early efficacy results are encouraging and further clinical study is warranted.