Complete Revascularization Via Inferior Part-sternotomy

Coronary artery bypass grafting (CABG) has always been the gold standard for surgical treatment of coronary artery disease (CAD), especially for left main (LM) coronary disease, patients with high SYNTAX scores, and diabetes mellitus. By minimally invasive strategy, patients recover significantly faster in the early post-operative period. However, a prospective randomized controlled trials is needed to compare the ratios of complete revascularization between inferior part-sternotomy CABG and full median sternotomy CABG.

Objectives:

To verify the effectiveness and safety of minimally invasive coronary artery bypass grafting for complete revascularization of multivessel coronary artery disease via inferior part-sternotomy.

Study design:

This is a prospective, multicenter, open-label, randomized controlled trial. We aim to randomize 260 patients undergoing isolated CABG to compare the ratios of complete revascularization between inferior part-sternotomy CABG and full median sternotomy CABG from 9 hospitals in China. We consecutively screen patients during the study enrollment period and seek informed consent from all eligible patients. Patients who give informed consent are randomly assigned to undergo inferior part-sternotomy CABG or full median sternotomy CABG by a central randomization system. An expert group composed of three doctors with CABG qualifications will develop a plan achieving complete revascularization by coronary angiography images before the operation, including the number and location of proximal and distal anastomoses. The actual bypass procedure will be recorded and compared with the preoperative plan. We will follow-up participants until 10 years after the operation. To reduce the variation among surgeons, we require that all CABG are performed by qualified surgeons. The surgeons in this study needs to have experience in at least 100 cases of full median sternotomy CABG, and at least 5 cases of inferior part-sternotomy CABG.The ethics committees at all 9 participating hospitals approved this study.

Randomization A web-based central randomization system incorporated in the registration system is used for allocation (http://ccsr.cvs-china.com/). The randomization code with fixed block size is generated by SAS. Randomization is stratified by investigation center. When an eligible patient gives informed consent, the investigator logs in to the randomization webpage and obtain the random number along with treatment group (Inferior part-sternotomy or Full median sternotomy group) automatically distributed by the system after the basic patient information be confirmed. The statistician responsible for the randomization code and the staff who develops the Interactive Web-based Response (IWR) system are independent of each other.

Intervention Surgical procedure.The patient is placed in the supine position. Standard intubation and hemodynamic monitoring are used. Heparinization is standardized for on-pump CABG. The surgeon is given discretion to ensure that his choice in surgery would ensure the patient´s safety (including which graft to use or the choice of anatomic regions to revascularize). The surgeries are performed with the usual methods of cardiopulmonary bypass (CPB) with aortic cross-clamp technique. Myocardial protection strategies include blood cardioplegia and moderate hypothermia. For both types of surgeries, an excellent exposure is required.

Inferior part-sternotomy CABG.A sternal saw is used to split the sternum from the xiphoid process to the second intercostal space where the sternum is partially transected by turning the saw rightward. Remaining coronary bypassing techniques are same in both groups according to clinical practice and preference of the operator.

Full median sternotomy CABG. A midline skin incision is made over the sternum, starting from the sternal angle and extending slightly beyond the xiphoid process. The sternum is fully split by a sternal saw.

Medication. All participants are prescribed dual antiplatelet therapy with aspirin 100 mg plus clopidogrel 75 mg daily from the first day post-CABG until 3 months post-operation. Prescription of other concomitant medications such as β-blockers, statins, and antihypertensive agents is determined by local surgeons according to ACC/AHA guidelines.

The trial data will be analyzed on an intention-to-treat basis with patients included in the groups assigned at randomization, irrespective of future management and events.Demographic and clinical variables will be summarized as means (SDs) for continuous and counts (percentages) for categorical variables. Comparisons across the groups will be performed using a 2-tailed unpaired t test for continuous variables and the Pearson's χ2 test for categorical variables. A P value of less than 0.05 will be considered as statistically significant for all analyses.

Clinical events committee. All clinical events including myocardial infarction, stroke, target lesion revascularization, and death will undergo central adjudication by an independent clinical events committee (CEC).

• The harvest time of left Internal mammary artery (LIMA) [Time frame: During surgery]
• Aortic cross-clamp time [Time frame: During surgery]
• Overall operation time [Time frame: During surgery]
• Intraoperative real-time blood flow at each anastomosis [Time frame: During surgery]
• The total amount of postoperative chest tube drainage [Time frame: Up to 4 weeks]
• The graft patency rate by CTA at 5-7 days, 1 year, 3 years, 5 years, and 10 years after surgery [Time frame: 1week after the surgery；10 years after surgery]
• The rate of major adverse cardiac or cerebrovascular events (MACCE) at 5-7 days, 1 year, 3 years, 5 years, and 10 years after surgery [Time frame: 1week after the surgery；10 years after surgery]