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.