The goal of the trial was to evaluate one-year angiographic patency of bypass grafts done on the beating heart (off-pump) compared with conventional bypass surgery (on-pump).

Study Design

Study Design:

Patients Enrolled: 400
Mean Follow Up: One year
Mean Patient Age: Mean age 62 years

Patient Populations:

Clinically and angiographically suitable for grafting


Valvular disease, aortic aneurysm, ST elevation MI

Primary Endpoints:

Death/MI/stroke/hemodialysis within 30 days

Drug/Procedures Used:

Consecutive, nonselective cardiac surgery patients at a single center were randomized to either on-pump (n=192) or off-pump (n=208). Crossover was allowed at the discretion of the investigator. Coronary angiography was performed early (3-7 days after surgery) and late (at one year) in 255 patients. Four surgeons performed the operations at the center.

Principal Findings:

After crossovers, 203 patients were treated with on-pump bypass and 185 patients were treated with off-pump bypass, with one-year angiography performed in 132 and 123 patients, respectively. Early (3-7 days) postoperative arterial graft patency was 100% in both groups. Early patency of saphenous vein grafts was 92% in each group. At one-year follow-up, arterial graft patency was 91% in each group. There was no significant difference in saphenous vein graft patency (59% for on-pump vs. 49% for off-pump, p=NS).

Hospital length of stay was 6.8 days in the on-pump group and 5.8 days in the off-pump group (p=NS). Costs were lower in the off-pump group (3,777 Euros vs. 5,7575 Euros). There was no difference in the composite endpoint of death/MI/stroke/hemodialysis when analyzed by intent-to-treat (4.9% for on-pump vs. 2.9% for off-pump, p=NS), but when analyzed "as treated," patients in the off-pump group tended to have a lower event rate (5.2% vs 1.7%).


Among a nonselected, consecutive cohort of patients undergoing cardiac bypass surgery, use of off-pump bypass surgery was associated with similar early and one-year arterial graft patency and saphenous vein graft patency compared with conventional, on-pump surgery and no difference in the clinical composite endpoint of death, myocardial infarction (MI), stroke, or hemodialysis, although the overall event rates were low. These data differ from another randomized study by Khan NE, et al., who reported lower rates of graft patency at three months in patients undergoing off-pump bypass surgery (88% vs. 98%, p=0.002).

Overall arterial patency rates in the present trial were high at one year, while saphenous vein graft patency was relatively low. The single study design of the trial should be noted as a limitation of the trial, with only four surgeons performing the operations, with approximately one year of off-pump surgical experience each.


Straka Z, et al. Off-pump versus on-pump coronary surgery: final results from a prospective randomized study PRAGUE-4. Ann Thorac Surg. 2004;77:789-793.

Widimsky P, et al. One-Year Coronary Bypass Graft Patency: A Randomized Comparison Between Off-Pump and On-Pump Surgery Angiographic Results of the PRAGUE-4 Trial. Circulation. 2004;110:3418-3423.

Presented by Dr. Petr Widimsky at the American College of Cardiology Annual Scientific Session, March 2004.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: Renal Dialysis, Myocardial Infarction, Stroke, Follow-Up Studies, Cross-Over Studies, Coronary Angiography, Saphenous Vein, Length of Stay

< Back to Listings