Intraoperative transit-time flowmetry in patients undergoing coronary surgery to determine relationships between graft flow and patency and prior coronary interventions and flow demand: a retrospective study

Bypass Grafting to Circumflex: Left Internal Thoracic Artery versus Saphenous Vein

BACKGROUND

This study aimed to compare the short- and long-term outcomes of saphenous vein grafts (SVGs) and in situ left internal thoracic artery (LITA) grafts to the left circumflex artery (LCX) territory.

METHODS

This study included 678 patients who underwent LITA-left anterior descending (LAD) + SVG-LCX grafts and 286 patients who underwent right internal thoracic artery (RITA)-LAD + in situ LITA-LCX grafts from January 2002 to December 2020. Short-term and long-term clinical outcomes were compared using inverse probability of treatment weighting adjustment to reduce selection bias.

RESULTS

In-hospital mortality was significantly higher for the SVG-LCX group (p = 0.008), whereas deep sternal wound infection was significantly higher in the LITA-LCX group (p = 0.013).Survival rates at 5 and 10 years were 83.12 and 71.45% in the SVG-LCX group, whereas 75.24 and 65.54% in the LITA-LCX group (log-rank p = 0.114). Rates of freedom from cardiac events at 5 and 10 years were 92.82 and 85.24% in the SVG-LCX group, whereas 94.89 and 89.46% in the LITA-LCX group (log-rank p = 0.179).Univariate and multivariate logistic regression analysis showed that proximal severe stenosis was significantly protective against graft dysfunction before discharge (odds ratio, 0.43; 95% confidence interval, 0.23-0.81).

CONCLUSION

Deep sternal wound infection was significantly higher for LITA to LCX bypass whereas in-hospital mortality was higher for SVG to LCX. In situ LITA to LCX bypass grafting exhibited similar long-term outcomes with SVG to LCX bypass grafting in adjusted patient cohorts. Proximal severe stenosis of LCX was protective against graft dysfunction.

Intraoperative Assessment of Coronary Resistances: A New Quality Marker and Potential Tool to Predict Early Graft Failure after Coronary Artery Bypass Grafting?

Intraoperative assessment of graft patency is pivotal for successful coronary revascularization. In the present study we aimed to propose a new, easy to perform tool to assess anastomotic quality intraoperatively, and to investigate its potential reliability in predicting early graft failure. Intraoperative graft flowmetry of 63 consecutive patients undergoing CABG were prospectively collected. Transit time flowmetry and its derivatives were recorded. Coronary resistances were calculated according to Hagen–Poiseuille equation both during cardioplegic arrest and after withdrawal from cardiopulmonary bypass. Angiographic evidence of graft occlusion at follow-up was cross-checked with intraoperative recordings. After a mean follow-up of 10.4 ± 6.0 months, 22 grafts were studied, and occlusion was documented in five (22.7%). Occluded grafts showed lower flows and higher resistances recorded during aortic cross-clamping. Coronary resistances, recorded during aortic cross-clamping, greater than 2.0 mmHg/mL/min, showed a sensitivity of 80% and a specificity of 100% to predict graft failure. We propose the routine recording of coronary resistances during aortic cross-clamping as an additional tool to overcome the acknowledged limitation of TTF to predict graft occlusion at 1 year.