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Operative flow measurements and coronary bypass graft patency
Insights
Intraoperative blood flow in aorta-coronary artery saphenous vein grafts predicts graft patency. Low basal flow (<40 ml/min) significantly increases early and late graft failure rates.
Area of Science:
- Cardiovascular Surgery
- Vascular Grafting
- Surgical Outcomes
Background:
- Aorta-coronary artery saphenous vein grafts are crucial for myocardial revascularization.
- Graft failure remains a significant challenge in long-term patient outcomes.
- Predictive factors for graft patency require further elucidation.
Purpose of the Study:
- To assess factors influencing the failure of aorta-coronary artery saphenous vein grafts.
- To correlate intraoperative flow measurements with early and late graft patency.
- To evaluate the utility of vasodilatory maneuvers in predicting graft fate.
Main Methods:
- Postoperative angiography at one week and one year in 142 patients (310 grafts).
- Correlation of intraoperative basal flow and reactive hyperemia with graft patency.
- Assessment of papaverine-induced flow increase in relation to graft closure.
Main Results:
- Overall graft patency was 85.5% early and 76.8% at one year.
- Grafts with basal flow <20 ml/min had a 63% cumulative closure rate.
- Grafts with basal flow <40 ml/min showed a 36% cumulative failure rate.
- Absence of reactive hyperemia and low papaverine-induced flow increase were associated with higher closure rates.
Conclusions:
- Intraoperative basal flow measurements are valuable predictors of aorta-coronary artery vein bypass graft fate.
- Low intraoperative basal flow is strongly associated with increased early and late graft failure.
- Vasodilatory maneuvers provide limited additional predictive information compared to basal flow.
Abstract:
Early (one week) and late (one year) postoperative angiography was performed in 142 patients having 310 grafts (117 right coronary artery [RCA], 134 left anterior descending [LAD], and 59 circumflex coronary artery [CCA]) to assess the factors responsible for failure of aorta-coronary artery saphenous vein grafts. Early catheterization revealed an 85.5 per cent patency rate with similar rates for each artery (RCA 88 per cent, LAD 85 per cent, and CCA 81 per cent). At one year 238 grafts remained patent, for a cumulative patency rate of 76.8 per cent with a similar distribution for each vessel (RCA 75 per cent, LAD 78 per cent, and CCA 76 per cent). Intraoperative flow measurements were correlated with early and late patency. Grafts with a basal flow less than 20 ml. per minute have a 42 per cent early closure rate and a 21 per cent late closure rate (cumulative 63 per cent). A basal flow of less than 40 ml. per minute was associated with a 25 per cent early failure and an 11 per cent late failure rate (cumulative 36 per cent). Basal flow at levels greater than 40 ml. per minute was not associated with an increased probability of graft closure. Absence of reactive hyperemia (30 second graft occlusion) was associated with a 19 per cent probability of early closure and a 31 per cent probability of cumulative thrombosis. A papaverine-induced flow increase (15 mg. given into the graft) of less than 100 per cent over basal flow gave a 20 per cent probability of early failure and 30 per cent probability of cumulative closure. Thus intraoperative basal flow measurements are of predictive value in determining the fate of aorta-coronary artery vein bypass grafts, and vasodilatory maneuvers provide little additional information.