Summary
Although coronary artery bypass grafting (CABG) is usually performed with the use of cardiopulmonary bypass (on-pump CABG), CABG without bypass (off-pump CABG) might reduce the number of major adverse events related to the heart-lung machine and improve outcomes. Investigators discussed the results of 3 studies - the GOPCABE study [Diegeler A et al. N Engl J Med 2013, CORONARY study [Lamy A et al. N Engl J Med 2013], and the PRAGUE 6 trial [NCT00606372] - that tested this hypothesis.
- Cardiology Clinical Trials
- Interventional Techniques & Devices
- Cardiology Clinical Trials
- Interventional Techniques & Devices
- Cardiology
Although coronary artery bypass grafting (CABG) is usually performed with the use of cardiopulmonary bypass (on-pump CABG), CABG without bypass (off-pump CABG) might reduce the number of major adverse events related to the heart-lung machine (MACCRE) and improve outcomes. Investigators discussed the results of 3 studies that tested this hypothesis.
GERMAN OFF-PUMP CORONARY ARTERY BYPASS IN THE ELDERLY [GOPCABE] STUDY
Anno Diegeler, MD, PhD, University of Leipzig/Herz-und Gefässklinik GmbH, Abteilung Herzchirurgie, Bad Neustadt, Germany, presented the results of the GOPCABE study [Diegeler A et al. N Engl J Med 2013], which showed no significant difference in clinical outcome between the 2 approaches at 30 days and at 12 months.
In GOPCABE, patients aged ≥75 years who were scheduled for elective first-time CABG were randomly assigned to off-pump (n=1271) or on-pump surgery (n=1268). The primary endpoint was a composite of death, myocardial infarction (MI), additional revascularization, stroke, and new onset renal replacement therapy 30 days after surgery.
At 30 days, the primary composite endpoint was not significantly different between the 2 treatments (7.8% for off-pump vs 8.2% for on-pump; OR, 0.95; 95% CI, 0.71 to 1.28; p=0.74). Of the components of the primary endpoint, only the repeat revascularization rate was significantly different and favored the traditional on-pump technique (1.3% vs 0.4%, respectively; p=0.04).
The investigators noted no significant differences between the 2 groups for the primary composite endpoint or repeat revascularization at 12 months. The results were similar in a per-protocol analysis that excluded the 177 patients who had crossed over from their assigned treatment to the other treatment. A potential limitation of this study was that it was a modified intent-to-treat analysis and only local data confirmation was performed.
CORONARY ARTERY BYPASS SURGERY OFF- OR ON-PUMP REVASCULARIZATION [CORONARY] STUDY
André Lamy, MD, MHSc, McMaster University, Hamilton, Ontario, Canada, reported the 1-year results of the CORONARY study [Lamy A et al. N Engl J Med 2013]. The 30-day results have been previously published [Lamy A et al. N Engl J Med 2012]. As with GOPCABE, the investigators found no significant differences in the primary composite outcome or in the occurrence of major clinical events between the 2 groups.
The study was conducted in 4752 patients (aged ≥70 years or younger patients with risk factors) from 79 sites in 19 countries. It utilized a surgical expertise-based design, whereby only surgeons considered to have expertise in the specific type of surgery were assigned to perform that procedure. Patients were randomly assigned to off-pump (n=2375) or on-pump CABG (n=2377). Clinical outcomes were assessed at 1 year. Quality of life and cognitive function were assessed at discharge, 30 days, and 1 year.
The primary composite endpoint (death, nonfatal stroke, nonfatal MI, or nonfatal new renal failure requiring dialysis) was not significantly different between off-pump (12.1%) and on-pump procedures (13.3%; HR, 0.91; 95% CI, 0.77 to 1.07; p=0.24). There were no individual differences between the 2 groups in the primary endpoint components, rate of revascularization procedures, quality of life, neurocognitive functions, or in any of the subgroup analyses.
The authors noted that, based on mid-term results, both procedures are reasonable options when in experienced hands.
ON-PUMP VERSUS OFF-PUMP CABG IN HIGH-RISK PATIENTS EUROSCORE 6+ [PRAGUE6] STUDY
The PRAGUE 6 trial [NCT00606372] results indicated that off-pump surgery in high-risk patients is associated with a lower incidence of serious complications and is a safer way of direct revascularization in these patients. Jan Hlavicka, MD, Kralovske Vinohrady University Hospital, Prague, Czech Republic, presented the findings of this prospective, randomized, single center, intention-to-treat assessment study.
The primary endpoint was the composite of death, MI, stroke, and new renal failure requiring hemodialysis at 30 days post operation. Patients were mean age 74 years with a mean additive EuroSCORE (Table 1) of 7.7; approximately 64% of the 206 enrolled patients had a recent MI. A total of 206 patients were randomly assigned to off-pump (n=98) or on-pump CABG (n=108).
EuroSCORE Risk Assessment Criteria
At 30 days, the primary composite endpoint was significantly lower in the off-pump (9.2%) versus on-pump group (20.6%; HR, 0.41; 95% CI, 0.19 to 0.91; p=0.028; Figure 1), driven exclusively by a nearly 3-fold increase in the rate of MI between the off-pump and on-pump groups (4.1% vs 12.1%; HR, 0.32; 95% CI, 0.11 to 0.99; p=0.048). Off-pump patients tended to have a lower incidence of secondary endpoints (eg, need for red blood cell transfusion and re-exploration for bleeding or tamponade). Study limitations included the small number of patients, single-center design, use of only 5 surgeons, and short-term (30-day follow-up) results.
Incidence of Combined Primary Endpoint During First 30 Days
Reproduced with permission from Hlavicka, MD.
Taken together, the conflicting results of these 3 studies (2 showed no difference, 1 favored off-pump CABG) indicate a need for larger, well-controlled studies with longer follow-up. Of particular interest is whether there are patients for whom one approach may be safer than the other.
- © 2013 MD Conference Express®
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