Results
During the study period, 2978 cases of cardiac surgery were performed in our institution, of which 707 cases were identified as isolated CABG (687 cases (97.2%) were off- pump). Of these, 94 cases were >80 years old at the time of surgery. Table 1 shows the pre-operative characteristics of the 613 cases in the young group and 94 cases in the old group. The old group showed a higher proportion of females, smaller body size and lower frequencies of diabetes, dyslipidemia and smoking history compared to the young group. The older group displayed lower renal function and higher frequency of anemia compared to the young group. Euroscore II and Clinical Frailty Scale were significantly higher in the old group than in the young group. The old group displayed a higher frequency of left main trunk disease than the young group, but pre-operative echocardiographic findings were broadly comparable. Table 2 shows the operative results. The old group had a shorter operative time, lower frequency in the usage of right internal thoracic arteries (ITAs), and a greater frequency of transfusion than the young group. The number of distal anastomoses was identical between groups. Cardiopulmonary bypass was used for 3.3% of cases in the young group, whereas all cases in the old group were treated using OPCAB, as intended. Graft patency rate was 97.0% in the young group and 96.2% in the old group. Post-operative hospitalization was longer in the old group, but ventilator time and stay in the intensive care unit were comparable between groups. Eighty of 94 old patients (85.1%) were discharged to home. Fourteen patients were transferred to another hospital, with 13 for further rehabilitation, and 1 for treatment of cerebral infarction. Operative/in-hospital death rates were very low in both groups (young group, 0.5%; old group, 0%).
The old group required temporary post-operative hemodialysis and suffered atrial fibrillation more frequently than the young group, but no significant differences were seen in other morbidities, including re-intubation, re-exploration, mediastinitis or cerebral infarction.
The collection rate for follow-up data was 100%, with a mean follow-up of 1318 days (range, 40–4309 days). Figure 1 shows the survival curve for all-cause death. Actual 1-, 3-, and 5-year survival rates were 92.1%, 81.2% and 68.3%, respectively. Twenty-eight deaths occurred during the observational period. Leading causes of late death were infection, including pneumonia (n=7). Other causes of death were heart failure in 5 cases, neurological and natural death (death from old age) in 4 cases each, cancer in 3 cases and renal failure in 2 cases.