Echocardiographic identification of iatrogenic injury of the circumflex artery during minimally invasive mitral valve repair

Abstract

Background: Injury to the circumflex artery after mitral valve (MV) repair or replacement is a recognized complication of this procedure. We designed an echocardiographic method to visualize the course and flow of the circumflex artery, to detect iatrogenic injury to this structure intraoperatively, as well as to predict the coronary dominance pattern in MV surgery patients.

Methods: After Ethics Committee approval, a prospective study was undertaken in 110 patients undergoing minimal invasive MV repair. Intraoperative transesophageal echocardiography was used to visualize the circumflex artery using a combination of B-mode imaging and color Doppler with different Nyquist limits. The course of the circumflex artery and the coronary sinus and their corresponding diameters were documented at the proximal and distal ends of both vessels. Preoperative angiographic data were used to determine the coronary dominance type.

Results: The course of the circumflex artery could be detected proximally in 109 patients (99%), to the point of intersection with the coronary sinus in 99 patients (90%), and distal to this intersection in 95 patients (86%) using our technique. Three patients had evidence of iatrogenic aliasing (circumflex stenosis) or "no flow" (circumflex occlusion) on transesophageal echocardiography examination after repair and therefore underwent surgical or percutaneous correction. All 3 of these patients had an uncomplicated postoperative course thereafter with no evidence of perioperative myocardial infarction. All remaining patients with normal circumflex examinations after repair did not show any clinical evidence of myocardial infarction or unstable hemodynamics postoperatively. The 95% confidence interval for the diameter of the proximal circumflex artery was 4.5 mm to 5.6 mm for the left dominant type patients and 3.8 mm to 4.2 mm for the right dominant and balanced type patients (p = 0.01).

Conclusions: The early recognition of iatrogenic injury of the circumflex artery is feasible with intraoperative transesophageal echocardiography examination, and may lead to treatment before extensive myocardial infarction occurs. We suggest that visualization of the circumflex artery with our technique should be performed more frequently in patients undergoing MV surgery.