Randomized Comparison of Minimally Invasive Direct Coronary Artery Bypass Surgery Versus Sirolimus-Eluting Stenting in Isolated Proximal Left Anterior Descending Coronary Artery Stenosis - MIDCAB Versus SES in Proximal LAD Lesions

Description:

Randomized trials in patients with isolated proximal left anterior descending (LAD) lesions suggest that minimally invasive direct coronary artery bypass (MIDCAB) surgery with the left internal mammary artery (LIMA) as bypass graft is superior to percutaneous coronary intervention (PCI) with bare-metal stents (BMS), predominantly due to a significant reduction in reintervention. Sirolimus-eluting stents (SES) are considered superior to BMS in preventing restenosis. Hence, the current trial sought to establish the noninferiority of SES compared with MIDCAB in patients with isolated proximal LAD stenosis.

Hypothesis:

SES would be noninferior compared with MIDCAB in patients with isolated proximal LAD stenosis.

Study Design

Study Design:

Patients Screened: 213
Patients Enrolled: 130
Mean Follow Up: 1 year
Mean Patient Age: 66 years
Female: 30
Mean Ejection Fraction: 65%

Patient Populations:

  • Age >18 years
  • Isolated proximal LAD stenosis >50% (between origin of left circumflex artery and first septal perforator)
  • Symptomatic
  • Presence of myocardial ischemia

Exclusions:

  • Acute coronary syndrome
  • Additional valvular heart disease requiring surgical intervention
  • Previous interventional or surgical treatment for coronary artery disease or valvular heart disease
  • Severe peripheral vascular disease
  • Significant carotid disease needing treatment
  • End-stage renal disease on hemodialysis
  • Overt congestive heart failure
  • Upper gastrointestinal bleeding <4 weeks
  • Contraindication to antiplatelet therapy
  • Diseases with limited life expectancy
  • Extreme obesity

Angiographic:
  • Total occlusions
  • Involvement of left main trunk
  • Stenosis of first diagonal branch
  • Intramyocardial course of LAD
  • Stenosis extending over a major diagonal branch
  • Stenosis at any other location requiring treatment

Primary Endpoints:

  • MACE (cardiovascular death, myocardial infarction [MI], TVR) at 12 months

Secondary Endpoints:

  • Cardiovascular death at 12 months
  • MI at 12 months
  • TVR at 12 months
  • Periprocedural adverse events at 30 days
  • Clinical status according to Canadian Cardiovascular Society classification
  • Physical exercise capacity on stress test
  • Quality of life

Drug/Procedures Used:

A consensus on patient eligibility had to be obtained from both the cardiac surgeon and the cardiologist before randomization. PCI was performed with SES using the femoral approach. High pressure stenting was the preferred strategy. Antiplatelet therapy was started the day before stenting with aspirin (at least 100 mg/day, subsequently 100 mg/day indefinitely) and clopidogrel (600 mg orally, followed by 75 mg/day for at least 12 months). During the procedure, unfractionated heparin (60 U/kg body weight) was administered. MIDCAB was performed under general anesthesia with a left anterolateral minithoractomy. The LIMA was harvested under direct vision and divided distally. Antiplatelet therapy consisted of aspirin 100 mg/day indefinitely.

Concomitant Medications:

Aspirin (100%), statins (98%), angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker (98.5%), beta-blockers (98%), and clopidogrel (100% PCI, 34% CABG)

Principal Findings:

A total of 130 patients were randomized, 65 to each arm. Baseline characteristics were fairly similar. About 26.5% of the patients had diabetes, and 16% were current smokers. Prior MI was noted in about 23% of the patients. Median interval to PCI and MIDCAB following randomization was 1 and 2 days, respectively. Only two patients crossed over from the MIDCAB arm to PCI—one patient received a saphenous vein graft rather than a LIMA, and in four patients, conversion to full open sternotomy was necessary. Three patients in the SES arm received BMS.

The mean lesion length was about 12 mm. About 22% of these lesions were calcified. Periprocedural complications were significantly lower in the SES arm compared with MIDCAB (3.1% vs. 16.9%, p = 0.02). Median hospital length of stay was also significantly lower in the PCI arm (3 vs. 13 days, p < 0.001).

In the intention-to-treat analysis, the incidence of major adverse cardiac events (MACE) was similar between the two arms (7.7% vs. 7.7%, p = 0.03 for noninferiority). No cardiac deaths were noted in either arm. MI within 30 days was lower in the SES arm (1.5% vs. 7.7%, p < 0.001 for noninferiority). Target vessel revascularization (TVR) was more common in the SES arm, but did not meet criteria for noninferiority (6.2% vs. 0%, p for noninferiority = 0.21). Patients in both arms showed significant improvement from baseline in clinical symptoms and quality of life; however, there was no difference between the two arms.

Interpretation:

The results of this small, single-center, randomized, controlled trial indicate that PCI with SES is noninferior to MIDCAB with LIMA to the LAD at 1 year. Despite the use of DES, the rate of TVR was still higher in the PCI group compared with CABG, which is similar to that noted in the recent SYNTAX trial.

These results are interesting, but need to be replicated by larger multicenter studies. Moreover, the low incidence of MACE noted in this trial may not be replicable in smaller community-based practices.

References:

Thiele H, Neumann-Schniedewind P, Jacobs S, et al. Randomized comparison of minimally invasive direct coronary artery bypass surgery versus sirolimus-eluting stenting in isolated proximal left anterior descending coronary artery stenosis. J Am Coll Cardiol 2009;53:2324-31.

Clinical Topics: Anticoagulation Management, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Atherosclerotic Disease (CAD/PAD), Aortic Surgery, Interventions and Coronary Artery Disease

Keywords: Coronary Artery Disease, Sternotomy, Body Weight, Heparin, Ticlopidine, Sirolimus, Constriction, Pathologic, Percutaneous Coronary Intervention, Stents, Quality of Life, Saphenous Vein, Mammary Arteries, Coronary Artery Bypass, Diabetes Mellitus


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