Full Sternotomy vs Mini-sternotomy for Ascending Aortic Pathology

1. Relevance of the study Hemiarch repair is an effective treatment for patients with ascending aortic aneurysm (AAR). All aortic procedures are routinely performed from full mean sternotomy but nowadays this standard could be performed via minimally invasive approach as well. There are some data that mini-J sternotomy is associated with less blood loss and blood products transfusion, improved lung function and eliminates wound complications risks. The aim of this study was to assess the morbidity and mortality after hemiarch repair via full or J-shaped mini-sternotomy. 2. Patients and methods Patients who will undergo hemiarch repair procedure via full sternotomy (FS group) will be compared with patients who will receive hemiarch repair via J-shaped mini-sternotomy (MS group). Baseline characteristics including preoperative clinical status, details on surgery, and postoperative outcomes will be compared between these groups. Follow-up data will be recorded.

Imaging All aortic measurements will be assessed by electrocardiography-gated computed tomographic angiography. Postoperative computed tomography of the aorta will be performed within 2 weeks after surgery. Analysis will be performed using 64-slice scanner Discovery NM-CT 570c (GE Healthcare, Milwaukee, WI, USA) with spatial resolution of the angiographic phase ranging from 0.6 to 1.25 mm. All measurements will be taken always in the plane perpendicular to the manually corrected local aortic centre line. Ascending aortic diameter will be measured at the level of the pulmonary artery bifurcation. The maximum aortic diameter (mm) will be measured from the outer contours of the aortic wall. All images will be independently assessed by two experienced cardiologists.

Surgical technique The hemiarch repair is performed via a full sternotomy or J-shaped mini-sternotomy under mild-to-moderate hypothermia (28-30°C) and antegrade cerebral perfusion through the innominate artery with side graft. The distal aortic anastomosis is performed using an open anastomosis fashion and involved resection of the inferior portion of the aortic arch from the base of the innominate artery to the projection of the origin of the left subclavian artery. Near infrared spectroscopy (Invos 5100, Somanetics Corp., USA) is used for cerebral monitoring during the operation. When the target temperature is achieved, lower body circulatory arrest with antegrade cerebral perfusion is initiated. The distal aortic anastomosis is performed with a running 4/0 polypropylene suture with a Dacron graft. Proximal aortic reconstruction including Bentall procedure, David procedure, proximal aortic anastomosis, etc. are performed during the rewarming period. The patient is weaned from cardiopulmonary bypass when the body temperature reached 36°C. The sequence of the surgical steps during the operation are the same for all patients.

Follow-up Follow-up will be performed according to the institutional database supplemented by individual patient records. Data will be obtained via medical records of clinical encounters or phone calls with patients and/or relatives. Postoperative computed tomographic scans will be performed upon discharge, at 12 months from the last procedure and at 60 months thereafter.

• Delirium (percent) [Time frame: Perioperative/Periprocedural]
• Transient ischemic attack (percent) [Time frame: Perioperative/Periprocedural]
• Stroke (percent) [Time frame: during follow-up time - 60 months]
• Respiratory failure (percent) [Time frame: Perioperative/Periprocedural]
• New arrythmia (percent) [Time frame: during follow-up time - 60 months]
• Pericardial effusion (percent) [Time frame: Perioperative/Periprocedural]
• Heart failure (percent) [Time frame: during follow-up time - 60 months]
• Myocardial infarction (percent) [Time frame: during follow-up time - 60 months]
• Systemic embolism (percent) [Time frame: during follow-up time - 60 months]
• Acute kidney injury requiring renal replacement therapy (percent) [Time frame: during follow-up time - 60 months]
• Re-exploration rate (percent) [Time frame: during follow-up time - 60 months]