Oxygen Delivery During Retrograde Cerebral Perfusion in Humans

Cerebral protection using deep hypothermic circulatory arrest versus retrograde cerebral perfusion for aortic hemiarch reconstruction

BACKGROUND

With evolutions in technique, recent data encourage the use of cerebral perfusion during aortic arch repair. However, a randomized data have demonstrated higher rates of neurologic injury according to MRI lesions using antegrade cerebral perfusion during hemiarch reconstruction.

METHODS

This was a retrospective review of two institutional aortic center databases to identify adult patients who underwent aortic hemiarch reconstruction for elective aortic aneurysm or acute type A aortic dissection. Patients were stratified according to cerebral protection method: (1) deep hypothermic circulatory arrest (DHCA) group versus (2) DHCA/retrograde cerebral perfusion (RCP) group.

RESULTS

A total of 320 patients and 245 patients underwent hemiarch reconstruction for aortic aneurysm electively and aortic dissection, respectively. In aneurysmal pathology, the DHCA group included 133 patients and the DHCA/RCP group included 187 patients. Operative mortality was 0.8% in the DHCA group and 2.7% in the DHCA/RCP group (p = 0.41). Kaplan-Meier survival estimates revealed comparable 2-year survival (p = 0.14). In dissection, 43 patients and 202 patients were included in the DHCA group and the DHCA/RCP group, respectively. Operative mortality was equivalent between the two groups (11.6% in the DHCA group and 9.4% in the DHCA/RCP group, p = 0.58). Long-term survival was similar at 2 years between the groups (p = 0.06). Multivariable analysis showed cerebral perfusion strategy was not associated with the composite outcome of operative mortality and stroke.

CONCLUSIONS

In treating both elective and acute ascending aortic pathologies with hemiarch reconstruction, both DHCA alone or in combination with RCP yield comparable results.

Cerebral protection strategies in aortic arch surgery: A network meta-analysis

OBJECTIVE

Cerebral protection for aortic arch surgery has been widely studied, but comparisons of all the available strategies have rarely been performed. We performed direct and indirect comparisons of antegrade cerebral perfusion, retrograde cerebral perfusion, and deep hypothermic circulatory arrest in a network meta-analysis.

METHODS

After a systematic literature search, studies comparing any combination of antegrade cerebral perfusion, retrograde cerebral perfusion, and deep hypothermic circulatory arrest were included, and a frequentist network meta-analysis was performed using the generic inverse variance method. The primary outcomes were postoperative stroke and operative mortality. Secondary outcomes were postoperative transient neurologic deficits, myocardial infarction, respiratory complications, and renal failure.

RESULTS

A total of 68 studies were included with a total of 26,968 patients. Compared with deep hypothermic circulatory arrest, both antegrade cerebral perfusion and retrograde cerebral perfusion were associated with significantly lower postoperative stroke and operative mortality rates: antegrade cerebral perfusion (odds ratio [OR], 0.62; 95% confidence interval [CI], 0.51-0.75; and OR, 0.63, 95% CI, 0.51-0.76, respectively) and retrograde cerebral perfusion (OR, 0.66; 95% CI, 0.54-0.82; and OR, 0.57; 95% CI, 0.45-0.71, respectively). Antegrade cerebral perfusion and retrograde cerebral perfusion were associated with similar incidence of primary outcomes. No difference among the 3 techniques was found in secondary outcomes. At meta-regression, circulatory arrest duration correlated with the neuroprotective effect of antegrade cerebral perfusion and retrograde cerebral perfusion compared with deep hypothermic circulatory arrest. Unilateral or bilateral antegrade cerebral perfusion and arrest temperature did not influence the results.

CONCLUSIONS

Antegrade cerebral perfusion and retrograde cerebral perfusion are associated with better postoperative outcomes compared with deep hypothermic circulatory arrest, and the relative benefit increases with the duration of the circulatory arrest. No differences between antegrade cerebral perfusion and retrograde cerebral perfusion were found for all the explored outcomes.

Central Nervous System Protection in Cardiac Surgery

Neurological dysfunction and stroke following cardiac surgery and thoracic surgery requiring hypothermic circulatory arrest is a well-defined problem. The original studies in CABG patients identified risk factors, such as prior stroke and lower educational level. There is older evidence suggesting that higher perfusion pressures during cardiopulmonary bypass are helpful. Hyperthermia during rewarming on cardiopulmonary bypass and postoperative hyperthermia have been associated with adverse cognitive outcomes. Glucose management intraoperatively remains controversial, but most now advocate for moderate glucose control using insulin, if required. The subset of patients having thoracic aortic surgery requiring periods of aortic discontinuity are particularly problematic. A cerebral protection strategy should be determined, and this may include hypothermic circulatory arrest, selective cerebral perfusion, or retrograde cerebral perfusion. All of these techniques have been associated with good surgical outcomes, but there is little information on cognitive outcomes of thoracic aortic surgery.