Randomized Comparison of Off-Pump and On-Pump Multivessel Coronary-Artery Bypass Surgery - Off-Pump vs. On-Pump Multivessel Coronary-Artery Bypass Surgery

Description:

The goal of the trial was to compare graft patency and clinical outcomes of coronary-artery bypass surgery without cardiopulmonary bypass and cardiac arrest ("off pump") versus conventional "on-pump" surgery.

Study Design

Study Design:

Patients Enrolled: 104
Mean Follow Up: Three months
Mean Patient Age: Mean age 63 years
Female: 13

Patient Populations:

Isolated, first-time coronary-artery surgery requiring at least three grafts

Exclusions:

Age <30 years or >80 years; indication for additional surgical procedures; documented stroke within the preceding six months; carotid-artery stenosis >70%; documented myocardial infarction in the preceding three months; poor left ventricular function, with an ejection fraction <20%; pregnancy and breast feeding; inability to provide written informed consent; and history of complications after diagnostic angiography

Drug/Procedures Used:

Patients requiring at least three grafts were randomized to on-pump coronary-artery bypass grafting (n=50) or off-pump surgery (n=54). Surgery was performed by one of two surgeons at the site. Randomization was stratified according to the surgeon to ensure a balance in the number of each type of procedure performed by the surgeon. Angiographic follow-up was performed at three months.

Concomitant Medications:

A standardized anesthetic protocol was used in all patients.

Principal Findings:

The number of grafts received in each arm did not differ: 3.4 grafts in the on-pump group versus 3.1 in the off-pump group, p=0.41. Median postoperative length of stay did not differ between the groups (seven days in each group, p=0.08).

Troponin T levels were higher in the on-pump group versus the off-pump group at six and 12 hours postoperatively (p<0.001 for each), but there was no difference by 24 hours. The area under the curve of troponin T levels was higher during the first 72 hours in the on-pump group than in the off-pump group (30.96 hr/7•µg/l vs. 19.33 hr•µg/l, p=0.02).

At three-month angiographic follow-up, more grafts were patent in the on-pump group (98%, 127/130) compared with the off-pump group (88%, 114/130, p=0.002). The patency rate was higher for all graft territories in the on-pump group than in the off-pump group (right coronary artery p=0.01; left anterior descending artery p=0.07).

There was no difference in minimum lumen diameter (1.63 mm with on-pump vs. 1.46 mm with off-pump, p=0.37), but percent stenosis trended higher in the off-pump group (21.19% vs. 34.67%, p=0.06). No patients died in either arm, and there was no difference in adverse events (two in the on-pump group vs. one in the off-pump group, p=0.50).

Interpretation:

Among patients undergoing coronary-artery bypass surgery requiring at least three grafts, performing surgery without cardiopulmonary bypass ("off pump") was associated with a lower patency rate at three-month angiographic follow-up compared with conventional "on-pump" surgery.

Prior studies have demonstrated a shorter length of stay, reduced need for transfusion, and less atrial fibrillation in patients who undergo off-pump surgery. However, the issue of graft patency with on- versus off-pump surgery had not been extensively studied, particularly in the setting of multivessel disease.

Off-pump surgery was associated with lower troponin levels in the immediate postoperative period, suggesting less myocardial injury, but these differences dissipated by 24 hours. While randomized, it should be noted that the study was conducted at a single site by two surgeons.

References:

Khan NE, De Souza A, Mister R, et al. A randomized comparison of off-pump and on-pump multivessel coronary-artery bypass surgery. N Engl J Med 2004;350:21-8.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias

Keywords: Follow-Up Studies, Coronary Artery Bypass, Off-Pump, Troponin T, Coronary Disease, Atrial Fibrillation, Constriction, Pathologic, Heart Arrest, Cardiopulmonary Bypass, Coronary Vessels, Length of Stay


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