Coronary bypass graft fate: angiographic grading of 1400 consecutive grafts early after operation and of 1132 after one year

Early and late patency of aortocoronary vein grafts

Early patency (two weeks) of 331 aortocoronary vein grafts was 89%. Late patency (one year) of 122 restudied grafts was 80%. A cumulative one year patency of 72% was calculated. Patency was similar for SV grafts, sutured distal to stenosis and segmental obstruction. Early patency was significantly decreased when the peroperative graft blood flow was 20 ml/min or less or the diameter of the recipient coronary artery was smaller than 1.5 mm. Cumulative one year patency was lower in symptomatic patients (54%) than in those who underwent consecutive reevaluation (80%). There was a trend towards improved patency rates for graft anastomosed to the left anterior descending coronary artery and grafts without pre-existing pathological changes. Patient parameters, such as at operation, sex, smoking habits, hypertension, lipid abnormalities, diabetes, previous myocardial infarction or depressed left ventricular function, had no bearing on patency. Graft failure occurring, despite refined surgical technique, is usually due to pathological changes of the vein graft per se or the recipient coronary artery and its vascular bed.

Prospective angiographic assessment of factors affecting early patency of saphenous vein-coronary artery bypass grafts

Between November 1977 and September 1978, early post-operative angiography was performed in 50 of 53 consecutive patients undergoing coronary artery bypass surgery. An average of 2.4 grafts per patient were applied. The overall patency rate was 82% and was not affected by the degree of proximal native vessel stenosis. Grafts to circumflex marginal vessels had a significantly lower (P < 0.05) patency rate (72%) than grafts to the left anterior descending (84%) and its diagonal branches (85%), or to the right coronary artery (90%). Ten single grafts were applied and all were patent. Forty-nine of the 50 patients had at least one patent graft. Fifty-three per cent of the grafts were considered of excellent quality and 25% patent but of fair quality only. There was a 100% patency rate for vessels of 2 mm diameter or more, which is significantly better (P < 0.01) than for vessels of 1-2 mm diameter (78%) or for vessels of less than 1 mm diameter (50%). There was a suggestion of a lower patency rate (74%) for vessels with evidence of distal disease, compared with vessels without such disease (85%). An assessment of the overall quality of the recipient vessel was made, taking both diameter and disease into account. This showed improved results for better quality vessels in terms of graft patency (P < 0.1) and graft quality (P < 0.05).

Failure of antiplatelet and anticoagulant therapy to improve patency of grafts after coronary-artery bypass: a controlled, randomized study

Fifty patients who underwent aortocoronary saphenous-vein bypass-graft surgery were randomly assigned to one of three groups to determine the effects of antiplatelet or anticoagulant therapy on graft patency. Twenty-four patients served as controls; 13 patients received aspirin (325 mg three times a day) and dipyridamole (75 mg three times a day); and 13 patients received closely regulated warfarin therapy. Medications were begun on the third post-operative day. Six months after surgery, all patients underwent coronary angiography to assess graft patency. There were no statistically significant differences between groups in various clinical, hemodynamic and angios, 27 of 33 grafts (82 per cent) with aspirin and dipyridamole and 29 of 37 grafts (78 per cent) with warfarin (P less than 0.5), all patients had at least one patent graft. Postoperative treatment either with aspirin and dipyridamole or with warfarin failed to improve the patency of the grafts.