Atrial fibrillation (AF) is commonly seen in patients with mitral regurgitation (MR). Mitral valve (MV) repair with simultaneous atrial ablation for the management of AF is the preferred method of treatment for MR associated with AF. There have been several reports of injury to the right or circumflex coronary artery (CxA) during MV surgery or with atrial ablation procedures.^1–3 To our knowledge, this is the first report of injury to the CxA during a minimally invasive MV repair combined with left atrial ablation. This case illustrates collaborative work between interventional cardiologists and cardiac surgeons to manage a complex cardiac problem that resulted in an excellent patient outcome.

       Case Report. A 75-year-old Caucasian male with a history of severe MR and AF was evaluated by angiography and was found to have no significant coronary artery disease. Transesophageal echocardiography (TEE) showed severe MR with a flail P2 segment. He had a reduced ejection fraction of 30–35% with a dilated left ventricle. The patient’s operative plan was to undergo minimally invasive MV repair with concurrent left atrial cryo-MAZE procedure.
       The patient underwent minimally invasive MV repair with P2 resection and insertion of a 34 mm Cosgrove

Figure 1. Angiogram showing total occlusion at the mid portion of the atrioventricular groove circumflex artery.

Annuloplasty Band (Edwards Lifesciences, LCC, Irvine, California). The Surgi-Frost^® device (ATS Medical, Inc., Minneapolis, Minnesota) was used to perform left atrial cryo-MAZE. Each lesion was created for 2 minutes to a temperature of -150°C. The following lesions were created: three endocardial lesions encircling the pulmonary veins, another from the pulmonary vein lesion set to the P3 segment of the MV, and one epicardial lesion along the coronary sinus. This was followed by over-sewing of the left atrial appendage. After reperfusion was established, TEE showed good wall motion with an ejection fraction of 40%. The patient was weaned successfully from cardiopulmonary bypass (CPB). On closing the incision, the patient developed hypotension requiring inotropic support. His electrocardiogram (ECG) showed ST elevations in the inferior and lateral leads. The TEE now showed new inferolateral hypokinesia. The patient was immediately transferred to the cardiac catheterization laboratory where coronary angiography showed total occlusion at the mid-segment of the atrio-ventricular groove CxA (Figure 1). Angioplasty using a Voyager™ RX 3.5 x 20 mm balloon (Guidant Corp., Indianapolis, Indiana) was performed (Figure 2), resulting in suboptimal blood flow. Intravascular ultrasound (IVUS) of the CxA was done after balloon angioplasty, which showed an extramural hematoma compressing the CxA (Figure 3). A Vision^® 3 x 15 mm stent (Guidant) was then deployed, resulting in the reestablishment of flow. Follow-up IVUS showed increased vessel area with suboptimal apposition of the stent within the vessel wall (Figure 4). Therefore, another inflation at higher atmospheric pressure with a Voyager RX 3.5 x 12 mm balloon was done inside the stent. The final angiogram of the left coronary system showed TIMI 3 flow with no evidence of dissection or

Figure 2. Post-angioplasty blood flow. Poor flow noted in the circumflex artery. Note the suture line is in close proximity to the circumflex artery.

extravasations of contrast (Figure 5). The ST-segment elevation decreased significantly, and his blood pressure showed marked improvement. An Intra-aortic balloon pump (IABP) was placed, and the patient was transferred to the intensive care unit. On postoperative day three, a transthoracic echocardiogram was performed which demonstrated an ejection fraction of 50–55% with no wall motion abnormalities. The patient’s postoperative course was complicated only by dysphagia. His upper endoscopy was negative for esophageal mass or stricture. After failing multiple swallow studies, a percutaneous endoscopic gastrostomy tube was placed. The patient was discharged and in his follow-up visit six weeks

Figure 3. IVUS post-balloon angioplasty showing extra mural hematoma. Soft tissue density with extrinsic compression of the circumflex artery with no evidence of atherosclerosis.

later, he was tolerating oral feedings with the gastrostomy tube removed.

       Discussion. As it traverses in the AV groove, the left CxA anatomically lies in close proximity to the posterior MV annulus, especially around the P1 segment. Therefore, the CxA could be injured while placing annuloplasty band sutures or more commonly after extreme decalcification of the posterior annulus and MV replacement.^4,5 This injury occurs secondary to placement of one of the sutures through the CxA or by direct compression by the prosthetic valve. In addition, the CxA has reported to be injured during AF ablation procedures with the many different energy sources.^3,6 To our knowledge, this is the first reported case of CxA injury after a minimally invasive combined MV repair and left atrial cryo-MAZE procedure.
       In our case, it is difficult to determine whether the placement of the annular sutures or the cryoablation that was responsible for the CxA injury. We believe that it is more likely that one of the sutures around the P1 segment of the posterior MV leaflet partially injured the CxA wall or a small branch, causing an external hematoma with resulting compression of the CxA. IVUS also demonstrated an external hematoma, suggesting an injury to a small branch with the hematoma compressing the CxA.

Figure 4. IVUS showing the stent in the circumflex artery with increased vessel circumference.

       As the injury was in the proximal CxA in the AV groove, injury with the cryo-probe is unlikely, since none of the lesions are placed in close proximity to the proximal CxA. The endocardial lesion from the pulmonary vein isolation lesion set to the posterior mitral annulus could cause CxA injury. However, to prevent this injury from occurring, we aim the probe to the P3 segment of the posterior MV, away from the CxA.
       Management of this type of injury is controversial. The first step is prompt recognition of the injury. Complete occlusion of the CxA usually presents as inability to wean the patient from cardiopulmonary bypass. However, if there is partial occlusion, as in this case, lateral wall ischemia is present. Intraoperative TEE is extremely helpful to determine wall motion abnormalities. In addition, ECG changes are also usually observed in the lateral leads. In our case, both ECG and TEE suggested ischemic changes in the left ventricular

Figure 5. Final result showing TIMI III flow in the circumflex artery.

myocardium supplied by the CxA. We believe that the management at this point depends on the patient’s hemodynamic status. An IABP is helpful in this situation to improve or maintain adequate hemodynamics. If the patient is stable hemodynamically, we advocate a catheter-based intervention. In the future, when hybrid operating suites are available, this type of event could be managed entirely in the operating room, expediting the diagnosis and intervention for this potentially lethal injury.
       This case demonstrates how a team approach between surgeons, anesthesiologists and cardiologists results in the prompt recognition and management of a complex problem, rendering an excellent outcome.
Conclusion. The most challenging aspect of hybrid cardiac surgery is to establish very close cooperation between cardiac surgeons and interventional cardiologists. Interventional cardiologists and the surgeons can work as a team to identify patients who could be effectively treated by the use of hybrid open and endoscopic techniques.