DISCUSSION
We herein presented a case of iatrogenic occlusion in the LCX after MVR, resolved with medical treatment. The LCX is located near the commissure of the mitral valve, and the coronary sinus is adjacent to the annulus of the posterior mitral valve leaflet; both vessels lie within the left atrioventricular groove. (3, 4) The LCX courses along the left atrioventricular groove; it ends near the margin of the LV in 85% to 95% of individuals, whereas it continues to the crux of the heart to develop the posterior descending artery (the dominant left coronary artery) in 5% to 15%. (3) Suggested mechanisms of injury to the epicardial coronary vessel following MVR include air embolism, the encirclement of the artery by suture, coronary spasm, the use of oversized prosthetic valves, the excessive removal of the anterior leaflet, and the close proximity of the LCX to the mitral annulus, especially in the left dominant ones. (2, 3, 8) The mechanism of injury, in our patient, was probably the pressure of the prosthetic valve onto the LCX, resulting in the occlusion of the artery. In such cases, symptom onset is usually intraoperative or immediately after surgery and common presentations are ventricular tachycardia or arrhythmia, ECG changes, elevated cardiac biomarkers such as troponin, and new wall motion abnormalities. (1, 9) Our case presented with ventricular tachycardia a few hours after surgery, with ST-segment changes in the inferior leads during tachycardia and an elevated level of troponin (1389 ng/L). Imaging can identify the cause of ventricular tachycardia, and angiography helps to evaluate the location of the injury and whether any further invasive procedure is required. (4, 10, 11) The hemodynamic stability of our patient enabled us to identify the presence and extent of the coronary lesion via angiography. (3)
There are only a few methods that are favored for the treatment of LCX injury, (9) with the choices limited to either redo surgery aimed at removing the prosthetic valve for replacement with a smaller one or aortocoronary bypass grafting onto the LCX distal to the site of the injury.(12) Initially, we performed PCI on our patient for stent implantation, which proved unsuccessful. Subsequently, of the 2 options of either valve removal for LCX revascularization followed by MVR or conservative medical treatment, we decided that, given the exigencies of time, the latter would be more advisable.