Surgical Management of Arterial Revascularization Therapies - SMART

Description:

The goal of the trial was to compare outcomes of coronary artery bypass surgery (CABG) without cardiopulmonary bypass (CPB) ("off-pump") versus conventional "on-pump" surgery.

Study Design

Study Design:

Patients Screened: 465
Patients Enrolled: 200
Mean Follow Up: One year
Mean Patient Age: Mean age 62 years
Female: 23

Exclusions:

Patients were not excluded for any pattern of coronary artery disease, ventricular dysfunction, or any other comorbidity. The only exclusion criteria were cardiogenic shock requiring emergency surgery or preoperative intra-aortic balloon pump.

Primary Endpoints:

Graft patency prior to hospital discharge and at one year

Secondary Endpoints:

Clinical and health-related quality-of-life outcomes and costs during one-year follow-up

Drug/Procedures Used:

Patients requiring CABG were randomized to have the procedure performed on-pump (n=99) or off-pump (n=98). The study was conducted at a single center by a single surgeon. Patients were not excluded for any pattern of coronary artery disease, ventricular dysfunction, or any other comorbidity.

Principal Findings:

Baseline characteristics were similar in both groups, with 33% diabetics and 48% ejection fraction ≤55%.

There was no difference in early (30-day) graft patency in arterial conduits (100% for off-pump and 99.2% for on-pump, p=0.99) or venous conduits (98.4% vs. 96.7%, respectively, p=0.48). Overall patency rates were 99.0% and 97.7%, respectively (p=0.22).

The primary endpoint of graft patency at one year did not differ between groups (93.6% for off-pump vs. 95.8% for on-pump, absolute difference, –2.2%; 95% confidence interval [CI] –6.1% to 1.7%; p=0.27). Patency rates were similar between groups in both arterial conduits (94.1% for off-pump and 98.1% for on-pump, p=0.26) and venous conduits (93.3% vs. 94.2%, respectively, p=0.93). Rates were also similar between surgery groups in each of the graft locations (left anterior descending, right coronary artery, and left circumflex coronary artery).

There were no significant differences in death, stroke, myocardial infarction, angina, or reintervention at 30 days or from 30 days to one year. Health-related quality-of-life measures were similar between groups at one-year follow-up, with the exception of the social function scale in the SF-36 questionnaire, which was better in the off-pump group (11.6 for off-pump vs. 6.02 for on-pump, p=0.049).

Costs per patient were lower for the off-pump group at hospital discharge ($18,796 for off-pump vs. $21,068 for on-pump, difference $2,272, 95% CI $755-$3,732, p=0.002) and trended lower at one year ($22,837 for off-pump vs. $24,792 for on-pump, difference $1,955, 95% CI –$766 to $4,727, p=0.08).

Interpretation:

Among patients with coronary artery disease undergoing CABG, there was no difference in early or late patency between patients randomized to "on-pump" or "off-pump" surgery. Clinical event rates also did not differ, but costs were lower in the off-pump group.

Several recent studies have addressed the issue of bypass surgery with or without CPB, and results have been mixed. In a study by Khan et al., graft patency was actually lower in the off-pump group than the on-pump group.

The present study was conducted by a single surgeon. It is unknown if similar results would be obtained by other surgeons and how operator experience and skill may have contributed to the results.

References:

Puskas JD, Williams WH, Mahoney EM, et al. Off-pump vs conventional coronary artery bypass grafting: early and 1-year graft patency, cost, and quality-of-life outcomes: a randomized trial. JAMA 2004;291:1841-9.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Interventions and Coronary Artery Disease

Keywords: Stroke, Myocardial Infarction, Coronary Artery Disease, Ventricular Dysfunction, Follow-Up Studies, Human Rights, Comorbidity, Questionnaires, Cardiopulmonary Bypass, Confidence Intervals, Coronary Artery Bypass, Diabetes Mellitus


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