Novadaq SPY: intraoperative quality assessment in off-pump coronary artery bypass grafting

Off-pump coronary artery bypass grafting may decrease operative morbidity when compared to on-pump bypass grafting; however, it is technically demanding and thus quality control is essential. This study assesses the clinical feasibility of a new, indocyanine green (ICG)-based imaging system (SPY; Novadaq Technologies; Toronto, ON, Canada) to monitor the quality of anastomoses and grafts in off-pump revascularization.

Thirty-eight consecutive patients undergoing nonemergent coronary artery bypass grafting without the use of extracorporeal circulation at two Swiss cardiac surgery clinics were included. On completion of bypass grafts, the quality of the grafts was assessed using the ICG-based imaging system. The imaging device comprises an 806-nm laser light source that is used to cause ICG to fluoresce and a near infrared-sensitive charged couple device videocamera that is used to capture the fluorescence images. ICG was administered through the central venous line, and images were acquired during the first pass of the ICG through the field of view. Graft flow (qualitative) and the quality of the grafts and anastomoses were assessed intraoperatively.

Between March 2002 and September 2002, a total of 38 patients (26 men and 12 women; mean +/- SD age, 64.6 +/- 10.5 years; body mass index, 27.1 +/- 2.9) underwent surgery and imaging at two institutions. One hundred seven of 124 grafts (45 arteries and 62 veins) were analyzed. Seventeen grafts could not be assessed due to difficulties in positioning. The imaging system was easy to handle, and no adverse reactions to ICG were observed. Four of the 107 grafts imaged required revision (three anastomotic constrictions and one graft dissection). Each imaging sequence required approximately 1.25 to 2.5 mg of ICG. The images were equivalent to angiography without the need for radiographs and catheter insertion. In addition, the course of coronaries that would otherwise be difficult to locate in obese patients could be detected using the imaging system. Biochemical and ECG data demonstrated an absence of intraoperative or postoperative myocardial damage, and no liver enzyme elevation or renal dysfunction.

This study supports the clinical utility of a ICG-based imaging system for the assessment of the quality of bypass grafts, which appears to be safe and simple to use.