Long term follow-up after coronary artery bypass graft surgery. Progression and regression of disease in native coronary circulation and bypass grafts

Angiographically demonstrable changes in bypass status and their relation to the disease in the native coronary circulation were studied in 221 patients one year and three years after coronary artery bypass graft surgery. The extent of coronary artery disease was scored according to the recommendations of the American Heart Aassociation and quantified following the method of Leaman. Patency of 570 grafts at one year was 79.6% and at three years 76.5%. The majority of grafts (83.5%) showed no change from one year to three years, 11.4% showed progression in disease, and 5.1% showed regression. The majority of grafts which occlude do so in the first year after surgery. After the first year, the graft attrition rate is 1.6% of grafts per year. The coronary score (0, no disease; >30, serious three vessel disease) before surgery was 14.2 ± 1.92 (mean ± 95% confidence) and dropped to 5.3 ± 0.76 at one year when corrected for patent grafts. The coronary score remains greater than zero because of early graft closure and/or untreated lesions. By three years the corrected coronary score increased to 7.2 ± 1.06 primarily because of progression of disease in the native coronary circulation. Two subgroups, formed on the basis of agina pectoris at three years, showed that progression of disease in the native circulation was identival, but that return of angina was highly correlated with whether or not this disease occurred in segments perfused by patent grafts. Those factors known to be risk factors for coronary artery disease do not appear to have a bearing on progression or regression of disease in the graft, not does the extent of coronary artery disease at the time of surgery correlate with eventual graft patency.