Deep Hypothermic Circulatory Arrest With Retrograde Cerebral Perfusion: How Long Is Safe?

BACKGROUND: Cerebral protection strategies during proximal aortic repair remains controversial due to lack of evidence and large patient cohort studies. We herein evaluated our 3-decade experience using hypothermic circulatory arrest with retrograde cerebral perfusion (DHCA/RCP) to evaluate for its safety and safe duration during proximal aortic repair. METHODS: All proximal aortic repairs using DHCA/RCP from January 1991 to December 2020 performed at our institution were included in the analyses. Perioperative variables were evaluated for mortality and cerebrovascular accident (CVA; combined stroke and transient ischemic attack). RESULTS: In all, 1429 repairs were performed using DHCA/RCP. Of these, 464 (32%) were acute aortic dissection and 297 (21%) were resternotomy. The median age was 61 years (interquartile range 50-70 years). Operative mortality was 8.9% and CVA occurred in 8.4% (stroke 7.8%, transient ischemic attack 0.6%). There was a linear relationship between the RCP time and the incidence of immediate postoperative CVA. Incidence of CVA was less than 5% when RCP time was less than 20 minutes, 6.3% at 30 minutes, and 11.5% at 60 minutes. Multivariable analysis demonstrated acute type A aortic dissection (odds ratio 2.58, 95% CI1.49-4.48, P = .001) was the only predictor for postoperative CVA but RCP time was not (odds ratio 0.991, 95% CI 0.962-1.02, P = .527). CONCLUSIONS: DHCA/RCA provided satisfactory outcomes after proximal aortic operations. The safe duration of RCP with DHCA was up to 30 minutes in our experience. When the circulatory arrest time is expected to exceed 60 minutes, other adjuncts for cerebral protection should be recommended.

Rapid cooling is a safe technique in patients undergoing circulatory arrest for aortic repair.

Objective: To evaluate our institutional experience with rapid cooling for hypothermic circulatory arrest in proximal aortic repair. Methods: We retrospectively reviewed data from 2171 patients who underwent proximal aortic surgery requiring hypothermic circulatory arrest between 1991 and 2020. Cooling times were divided into quartiles and clinical outcome event rates were compared across quartiles using contingency table methods. Incremental effect of cooling time was assessed in the context of other perfusion time variables using multiple logistic regression analysis. Results: Median age was 61 years (interquartile range, 49-70 years) and 34.1% of patients were women. The procedure was emergent in 33.5% of patients, 22.9% had a previous sternotomy. The median circulatory arrest time was 22 minutes, with retrograde cerebral perfusion used in 94% of cases. Median cardiopulmonary bypass time was 149 minutes, with an aortic crossclamp time of 90 minutes. Patients were cooled to deep hypothermia. The first quartile had cooling times ranging from 5 to 13 minutes, second 14 to 18 minutes, third 19-23 minutes, and fourth 24-81 minutes. Overall, 30-day mortality was 9.4%, and was not significantly different across quartiles. There was a statistically significant trend toward lower rates of postoperative encephalopathy, gastrointestinal complications, and respiratory failure with shorter cooling times (P < .001, .006, and < .001, respectively). There was no significant difference in rates of postoperative stroke or dialysis. Conclusions: Rapid cooling can be performed safely in patients undergoing aortic surgery requiring circulatory arrest without increasing mortality or stroke. There were significantly lower rates of coagulopathy, respiratory failure, and postoperative encephalopathy with shorter cooling times.