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OBJECTIVE: To acquire a detailed awareness of the anatomical relationship between circumflex coronary artery (CX) and mitral valve annulus (MVA), in order to identify potentially high risk anatomy, prior mitral valve surgery.
METHODS: From August 2015 to October 2016, 64 consecutive patients, electively referred for mitral valve surgery, underwent pre-operative multi-slice coronary computed tomography angiography (CCTA), with volume-rendered 3-dimensional and retrospective gated acquisition. The posterior portion of the mitral annulus was delineated using five main zones, which were numbered from 1 to 5 in anticlockwise direction: zones 1 and 5 were at level of antero-lateral and postero-medial commissures respectively, zone 2 was between zone 1 and the middle posterior annulus-zone 3- and zone 4 was between zones 3 and 5. High risk anatomy was arbitrarily defined as any zone where the CX-MVA distance was<3mm. CCTA’s data were integrated with those from preoperative coronary angiogram and 3-dimensional Transoesophageal Echocardiography (3D-TOE).
RESULTS: Right dominance was observed in 52 patients (81.25%), left dominance in 8 patients (12.5%) and balanced dominance in 4 patients (6.25%). The shortest CX-MVA distance was at Zone 1 (5.08 ± 3.28 mm). 18 patients were identified as high risk anatomy (mean distance at zone 1: 1.55 ± 0.77mm). Statistical difference was observed between zone 1 and all the zones (p<0.05). Left dominant and codominant coronary anatomy demonstrated a closer CX-MVA relationship and a statistical significance was seen at all the zones (p<0.05).
CONCLUSIONS: Preoperative knowledge of the anatomical relationships between MVA and CX, may be a useful tool to identify patients at potentially high-risk of CX flow disturbance during mitral valve surgery.