Abstract 746: Evaluation Of The Coronary Flow Between The Left And The Right Coronary Network In Patients With Triple Vessel Disease With Chronically Occluded Right Coronary Artery
Objective: The aim of this study was the evaluation of collateral blood flow (CBF) in the case of patient with 3-vessel disease and chronic occlusion of the right coronary artery undergoing surgical complete revascularization with off pump technique (Left Internal Thoracic Artery (LITA) to Left Anterior Descending Artery (LAD), Right Internal Thoracic Artery (RITA) to Left Circumflex Branch (LCx) and venous graft to Right Coronary Artery (RCA)). We attempted to assess the relationship between the left graft flows and collateral blood flow.
Methods: Twenty-one patients were included in this study: 19 males and 2 females, mean age 62.3±2.1 years, mean LVEF 56±2.8%. Nine patients had a previous history of myocardial infarct (MI). Preoperative Rentrop score was 1, 2 or 3 in respectively 4, 6 and 11 patients. We measured the transit time flow (Flowmeter MediStim®, Oslo, Norway) through the left coronary grafts (LITA and RITA) before and after unclamping the RCA bypass.
Results: Unclamping of the right coronary artery bypass graft was associated with 3.35±1.13 ml/min decrease in flow across the LITA (p = 0.01). The mean LITA flow among patients with previous MI was lower than in patients without MI (28±4ml/min; 48±10ml/min) (p=0.18). A correlation was observed between the LITA flow and LVEF (r=0.48, p=0.02) but not between RITA flow and LVEF (p=0.15). Unclamping of the right coronary artery bypass graft was associated with 5.89±1.59 ml/min decrease in flow across the RITA (p = 0.0017). This variation of flow was more important among patients Rentrop 3 compared to patients Rentrop 1 and 2 (p=0.03). No significant difference was found between the flow decrease across LITA and RITA in patients with or without preoperative infarction.
Conclusion: This study suggested that CBF to the occluded RCA is more provided by LCX and probably that its origin is upstream to stenoses in left coronary network. These small variations of flow observed in left grafts suggest that the collateral flow provided by these grafts is too low to avoid right coronary artery bypass in case of chronically occluded RCA.