Coronary Bypass Grafting With Minimal Extracorporeal Circulation System Versus Off-Pump Coronary Surgery - Coronary Bypass Grafting With Minimal Extracorporeal Circulation System Versus Off-Pump Coronary Surgery

Description:

The goal of the trial was to evaluate minimal extracorporeal circulation system (MECC) compared with off-pump coronary revascularization (OPCABG) for patients undergoing coronary bypass surgery.

Study Design

Study Design:

Patients Screened: 394
Patients Enrolled: 300
Mean Follow Up: 1 year
Mean Patient Age: Mean age 66 years
Female: 26

Patient Populations:

Scheduled for elective isolated myocardial revascularization performed via full median sternotomy and judged technically suitable for both OPCABG and MECC; indication for coronary surgery based on current published guidelines.

Exclusions:

Documented preoperative systemic proinflammatory status and/or steroid administration within 6 months before surgery; single-vessel disease.

Drug/Procedures Used:

Patients were randomized to either off-pump surgery (OPCABG group; n = 150) or minimal extracorporeal circulation (MECC group; n = 150). MECC is a fully heparinized, closed-loop circuit designed to minimize blood-air contact (absence of cardiotomy reservoir).

Principal Findings:

Operative characteristics were similar between groups, with a mean of 3.25 grafts per patient in the MECC group and 3.08 grafts per patient in the OPCABG group. Total operative time was slightly longer in the MECC group (mean 287 minutes vs. 256 minutes, p = 0.027), with a mean CPB time of 86.5 minutes in the MECC group. There were 5 patients who had difficulty weaning from extracorporeal circulation in the MECC group, requiring reinstitution of the MECC circuit and maximal inotropic support; there were 2 patients in the OPCABG group requiring an intra-aortic balloon pump.

Peri-procedural complications did not differ between the MECC and OPCABG groups, including similar ICU stays (mean 19.1 hours vs. 17.6 hours, p = 0.078), hospital stays (7.9 vs. 7.7 days), and 30 day mortality (n = 2 vs. n = 3), respectively. The mean reduction in hematocrit was 7.8% in the MECC group and 6.7% in the OPCABG group (p = 0.18). There was no difference in peak release of the inflammatory marker interleukin-6 between the MECC and OPCABG groups (181 vs. 167.2 pg/mL, p = 0.14), nor was there a difference in peak creatine kinase (326 vs. 419.3 mg/dL, p = 0.28). Peak S-100 protein, a marker of brain injury, trended higher in the MECC group (0.29 vs. 0.13 pg/mL, p = 0.058).

Clinical results were similar between the groups at 1 year, with a mortality rate of 2.7% in the MECC group and 3.4% in the OPCABG group (p = 0.99). There were 2 patients with recurrence of angina at 1 year in the MECC group and 5 patients in the OPCABG group. Presence of residual perfusion defect on myocardial nuclear scan trended to be less frequent in the MECC group (2% vs. 6%, p = 0.14; odds ratio 0.32, 95% CI 0.07-1.32). The 12 patients with a residual perfusion defect on myocardial nuclear scan underwent coronary angiography, with presence of occluded or severely stenotic coronary grafts in 3 and 6 patients, respectively (p = 0.33).

Interpretation:

Among patients undergoing coronary bypass surgery, use of minimal extracorporeal circulation system (MECC) was associated with similar peri-operative and 1 year results compared with off-pump coronary revascularization (OPCABG).

MECC has been suggested as an alternative method to reduce inflammatory activation and potentially reduced the need for blood transfusions associated with bypass surgery. A prior study compared MECC with traditional cardiopulmonary bypass surgery and showed large reductions in systemic inflammatory reaction. While the present study showed similar outcomes with MECC vs. OPCABG, the trial was small and underpowered to evaluate clinical events. Several studies have shown improved short term clinical outcomes with OPCABG versus traditional cardiopulmonary bypass surgery, but a higher need for long-term repeat revascularization with OPCABG, possibly due to fewer grafts placed or a higher rate of vein graft failure with OPCABG. The present study suggests cardiopulmonary bypass surgery with MECC may provide an additional alternative to OPCABG, but larger studies are needed to evaluate the clinical impact of these two surgical approaches.

References:

Mazzei V, et al. Prospective Randomized Comparison of Coronary Bypass Grafting With Minimal Extracorporeal Circulation System (MECC) Versus Off-Pump Coronary Surgery. Circulation. 2007;116:1761-7.

Clinical Topics: Cardiac Surgery, Dyslipidemia, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Atherosclerotic Disease (CAD/PAD), Lipid Metabolism, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging

Keywords: S100 Proteins, Operative Time, Coronary Artery Disease, Sternotomy, Weaning, Creatine Kinase, Interleukin-6, Extracorporeal Circulation, Length of Stay, Blood Transfusion, Hematocrit, Coronary Angiography, Brain Injuries, Cardiopulmonary Bypass, Coronary Artery Bypass


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