Early and medium-term results after on-pump and off-pump coronary artery surgery: a propensity score analysis

BACKGROUND: Comparative publications on beating-heart off-pump coronary artery bypass grafting (OPCAB) surgery versus conventional coronary artery bypass grafting (CCAB) surgery frequently do not offer conclusive information because of investigator bias. METHODS: Trying to eliminate this problem, a propensity score analysis of the data of all CCAB patients (n = 517) and OPCAB patients (n = 133) operated on by the same surgeons during the same time period (1998 to 2001) was applied. After matching patients with similar propensity score values, 97 CCAB patients and 72 OPCAB patients entered the final analysis. RESULTS: Early results were similar in both groups: the 30-day mortality reached 1.4% in the CCAB group and 2.8% in the OPCAB group; strokes did not happen. Perioperative myocardial infarctions occurred in 4.1% of the CCAB patients and 4.3% of the OPCAB patients. Drainage blood loss in the first 24 hours after surgery (830 +/- 687 mL, CCAB group; and 909 +/- 678 mL, OPCAB group) was similar (p = 0.06) in both groups. Medium term results (freedom from percutaneous transluminal coronary angioplasty or reoperation, freedom from myocardial infarction, freedom from stroke, and the quality of life) also were not significantly different between the off-pump and on-pump groups after a mean follow-up of 27 +/- 11 months. CONCLUSIONS: Our results suggest that elective-surgery patients with coronary artery disease can be operated on either on-pump or off-pump with the same early and late mortality and morbidity.     

Early neuropsychological dysfunction in elderly high-risk patients after on-pump and off-pump coronary bypass surgery

Purpose Advanced age is associated with systemic atherosclerosis and is a risk factor for neurological dysfunction after coronary artery bypass grafting (CABG). However, few studies have investigated early neurological dysfunction after off-pump CABG in elderly patients. Methods Data were collected prospectively on 218 patients (≥60 years) who underwent elective off-pump (n = 89) or on-pump CABG (n = 129). Four cognitive tests were performed preoperatively and 1 week postoperatively. Neuropsychological (NP) dysfunction was defined as a decrease in an individual's performance in more than two tests of at least 20% from baseline. We compared the incidence of NP dysfunction, stroke, graft patency grading, and systemic atherosclerosis between patients who underwent off-pump and on-pump CABG. Results Off-pump patients were more likely to have a history of cerebrovascular disease, peripheral vascular disease, smoking, multiple cerebral infarctions, and severe aortic atherosclerosis. None of the off-pump and three on-pump patients suffered intraoperative strokes (P = 0.27). The incidence of NP dysfunction was 11.2% in the off-pump group and 22.5% in the on-pump group, (P = 0.02). Multivariate analysis revealed that NP dysfunction was associated with cardiopulmonary bypass (CPB) and multiple cerebral infarctions. The off-pump group had fewer vessels grafted (2.4 vs 3.4; P < 0.01), and a higher rate of stenosis (>50%) and occlusion of the grafted vessels (13.0% vs 7.4%; P = 0.01) than the on-pump group. Conclusion Off-pump CABG reduced postoperative NP dysfunction in elderly patients with severe systemic atherosclerosis compared to on-pump CABG.     

Comparison of cerebral embolization during off-pump and on-pump coronary artery bypass surgery

BACKGROUND: Coronary artery bypass surgery with cardiopulmonary bypass carries a significant risk of perioperative brain injury. At least 1% to 5% will suffer a stroke, and at 3-months postoperatively approximately 30% are reported to have cognitive impairment assessed by neuropsychologic testing. In off-pump surgery cardiopulmonary bypass is not used and instrumentation on the ascending aorta is reduced. The main aim of this study was to assess if off-pump surgery reduces intraoperative cerebral embolization. METHODS: This was a prospective and randomized study of two comparable groups with regard to age, sex, years of education, preoperative cognitive functioning, and surgical characteristics. Fifty-two patients (29 off-pump) were monitored by the use of transcranial Doppler ultrasound for cerebral microembolization during surgery. Preoperative and postoperative clinical, cerebral magnetic resonance imaging, and neuropsychologic examinations were also carried out. RESULTS: There was a significant reduction in the number of cerebral microemboli during off-pump compared with on-pump surgery (16.3 [range 0 to 131] versus 90.0 [range 15 to 274], p < 0.0001). No significant difference with regard to the incidence of neuropsychologic performance (decline in 29% off-pump, 35% on-pump) or neuroradiologic findings at 3 months was found, and there was no association between the number of cerebral microemboli and cognitive outcome. CONCLUSIONS: This study clearly demonstrates that off-pump surgery leads to a reduction in intraoperative cerebral microembolization. A significant reduction in the number of off-pump patients with cognitive decline or ischemic brain lesions on cerebral magnetic resonance imaging could not be demonstrated in this relatively small patient population.     

Transit time flow measurement in on-pump and off-pump coronary artery surgery

OBJECTIVE: Transit time flow measurement is frequently used during coronary artery bypass with and without cardiopulmonary bypass to detect graft dysfunction resulting from technical errors. METHODS: Intraoperative transit time flow measurement measurements of 896 patients requiring surgery for double- or triple-vessel disease were reviewed retrospectively. Six-hundred and ninety-five patients were operated on-pump (Group A: coronary artery bypass with cardiopulmonary bypass), and 201 patients off-pump (Group B: coronary artery bypass without cardiopulmonary bypass). Transit time flow measurement measurements were analyzed for mean flow (mL/min). In total, measurements of 2247 grafts were analyzed. RESULTS: Transit time flow measurement flows were lower in coronary artery bypass without cardiopulmonary bypass patients (left internal thoracic artery to left anterior descending artery: Group A, 37 [31, 40] mL/min vs Group B, 24 [20, 26] mL/min; saphenous vein graft to left anterior descending artery: Group A, 46.5 [40, 56] mL/min vs Group B, 21 [14, 57] mL/min. Troponin I release was reduced in the coronary artery bypass without cardiopulmonary bypass patients, with median values of 7.8 [7.0, 8.3] microg/L in Group A and 1.2 [0.9, 2.3] microg/L in Group B. CONCLUSION: Evaluation of transit time flow measurement is valuable in determining coronary graft patency after coronary artery bypass with cardiopulmonary bypass and coronary artery bypass without cardiopulmonary bypass. Decreased troponin I release suggests a myocardial benefit of coronary artery bypass without cardiopulmonary bypass compared to coronary artery bypass with cardiopulmonary bypass, although the intraoperative transit time flow measurement flow measurements are markedly lower.     

Benefit to quality of life after off-pump versus on-pump coronary bypass surgery

BACKGROUND: Whether the clinical outcome of off-pump coronary artery bypass graft (OPCABG) surgery is superior to on-pump coronary artery bypass graft (CABG) surgery is still a matter of debate. However with the considerable reduction of mortality associated with CABG surgery in recent years, more subtle outcome indicators such as quality of life (QOL) become more important. The aim of this study was to compare midterm QOL after OPCABG with that after CABG procedures and with an age- and sex-matched standard population. METHODS: Quality of life was assessed using the Short-Form 36 Health Survey Questionnaire for 504 consecutive patients after CABG (n = 438) and OPCABG (n = 66) operated on between June 1999 and November 2000 at our institution. RESULTS: Except for single-vessel disease, which was more frequent in OPCABG compared with CABG procedures (13.6% versus 6.8%; p <0.01), the preoperative variables were similar. Median EuroSCORE (European System for Cardiac Operative Risk Evaluation) was 3.2 +/- 1.3 in the CABG group compared with 3.0 +/- 0.8 in the OPCABG group (p = not significant). After a mean follow-up of 10.8 +/- 0.5 months physical role function (73.5 +/- 38.3 versus 45.3 +/- 41.6; p <0.01) and emotional role function (75.3 +/- 40.3 versus 61.0 +/- 43.9; p <0.01) were significantly better in OPCABG than in CABG patients. Compared with a standard population, OPCABG patients were significantly impaired in emotional role function and CABG patients in physical and emotional role function. CONCLUSIONS: Midterm QOL after myocardial revascularization is fairly well preserved compared with an age- and sex-matched standard population and is superior after OPCABG compared with CABG. Whether this is only due to avoidance of cardiopulmonary bypass remains to be elucidated.