Between January 2003 and March 2019, 74 patients aged older than 75 years underwent elective TAR for arch aneurysm at Yokohama City University Medical Center. We excluded emergency cases of type A acute aortic dissection and aortic rupture and cases of redo aortic surgery for ascending aorta and aortic arch. Patients who underwent emergency surgery for aortic dissection or rupture of the aorta were not included because these conditions might have preoperative influence on the brain. Preoperatively, magnetic resonance imaging (MRI) or head computed tomography (CT), MR angiography (MRA), and carotid ultrasound were conducted to assess the brain, cerebral circulation, and the neck vessels, respectively.
We have been performing ICP during TAR since 2010. Until 2009, TAR was performed with conventional selective cerebral perfusion, in which the cannulae were directly inserted from the inside of the aorta after systemic perfusion cooling via various arterial cannulations.
All patients (n = 74) were divided into two groups according to the brain protection method used: the ICP method (ICP group, n = 46) and the SCP method (non-ICP group, n = 28).
Set-up during the ICP procedure
The bilateral axillary arteries were exposed before sternotomy. A 9-mm Dacron graft was anastomosed to the bilateral axillary arteries for systemic perfusion. After median sternotomy, bi-caval venous drainage was performed. The left common carotid artery (LCCA) was exposed without touching the aorta. The LCCA was proximally clamped and dissected, and a 12-Fr balloon-tipped cannula with a pressure monitor was inserted immediately. Extracorporeal circulation via the bilateral axillary artery and selective perfusion to the LCCA were simultaneously started. Separate roller pump was used to regulate the blood flow to LCCA. The mean pressure at the radial artery and LCCA were monitored and controlled between 40 and 70 mmHg. Circulatory arrest was induced at rectal temperature of 25°C. The brachiocephalic artery and left subclavian artery were clamped. ICP was immediately completed with blood flow through the bilateral axillary arteries and the LCCA (Figure 1).
Set-up during the non-ICP procedure
Systemic perfusion was achieved via the bilateral axillary and femoral arteries (n = 13), right axillary and femoral arteries (n = 5), bilateral axillary artery (n = 5), ascending aorta (n = 4), and ascending aorta and the bilateral axillary artery (n = 1).
With perfusion via the ascending aorta or the right axillary artery, the selective cerebral perfusion canulae were directly inserted from the inside of the aorta after circulatory arrest. When the bilateral axially arteries were used, the brachiocephalic artery and the left subclavian artery were clamped just after circulatory arrest, and the cerebral perfusion cannula was directed into the left carotid artery.
Neurological diagnosis
The postoperative neurological symptoms based on the clinical records were retrospectively reviewed. Postoperatively, intensivists checked the neurologic state of the patients every day in the intensive care unit. For symptomatic patients, the Department of Neurology was always consulted, and neurologists completed a neurological examination via CT scan in symptomatic patients. Postoperative cerebral infarction was defined as the persistence of permanent neurological dysfunction at discharge, which was accepted with the image and diagnosed by a neurologist. Transient neurologic dysfunction, which includes delirium, transient ischemic attack, and any neurologic dysfunction that was not judged as postoperative cerebral infarctions, was not assessed in this study.
Definitions
Cerebrovascular and carotid abnormality was defined as a carotid artery stenosis diagnosed via carotid ultrasound, which revealed >70% of stenosis in the area, or the occluded lesion of carotid or vertebral arteries and circle of Willis diagnosed by MRA. Previous stroke was defined as the preoperative clinical history of cerebrovascular disease that did not include transit ischemic attack.
Statistical analysis
Continuous data were expressed as median and interquartile range (25th–75th percentile). Discrete data were shown as counts and percentage. Continuous variables were compared with the Mann–Whitney U test, and categorical variables were compared with Pearson Χ2 test or Fisher exact test. Kaplan–Meier analysis was performed to calculate survival.