Original article
Adult cardiac
Cerebral Circulation During Retrograde Cerebral Perfusion: Evaluation Using Laser Speckle Flowgraphy

https://doi.org/10.1016/j.athoracsur.2018.11.067Get rights and content

Background

The cerebroprotective effect of retrograde cerebral perfusion (RCP) and selective antegrade cerebral perfusion (SCP) still remains controversial. Laser speckle flowgraphy has shown much promise for novel perioperative neuromonitoring by assessing blood flow of the optic nerve head. This study aimed to evaluate the cerebral microcirculation in humans using laser speckle flowgraphy during simple circulatory arrest, RCP, and SCP under moderate hypothermia and to investigate whether RCP under moderate hypothermia is a reliable method of cerebral protection.

Methods

A total of 23 consecutive patients who underwent a scheduled aortic arch or hemiarch surgical procedure on thoracic aorta aneurysm were enrolled. The laser speckle flowgraphy measurement that calculates mean blur ratio, a parameter of cerebral circulation, was obtained 6 times: after induction of anesthesia, baseline (T1), after initiation of cardiopulmonary bypass with cardiac arrest (T2), simple circulatory arrest (T3), RCP (T4), SCP (T5), and after the termination of cardiopulmonary bypass (T6).

Results

Both mean blur ratios of simple circulatory arrest and RCP were significantly decreased compared with baseline. In contrast, no significant differences were observed between simple circulatory arrest and RCP. The mean blur ratio of SCP was significantly increased compared with both simple circulatory arrest and RCP.

Conclusions

In conclusion, no significant difference was observed in the cerebral circulation between RCP and simple circulatory arrest without adjunctive strategy under moderate hypothermia. In contrast, the cerebral circulation during SCP was significantly higher than simple circulatory arrest and RCP. These results suggest that cerebral microcirculation may not be adequate during RCP compared with SCP under moderate hypothermia.

Section snippets

Study Design

This was a single-center, prospective, observational study. The study protocol was approved by the Asahikawa Medical University Research Ethics Committee (approval number: 15102) and was registered as a clinical trial (UMIN000034259). Written informed consent was obtained from all patients.

Inclusion Criteria

Consecutive patients who underwent scheduled aortic arch repair for aneurysm were enrolled. The candidates were screened for eligibility for participation in the study through preoperative assessment.

Study Population and Surgical Outcome

Table 1 shows a summary of the patients’ backgrounds. A total of 28 consecutive patients were enrolled. Preoperative magnetic resonance imaging and computed tomographic scans indicated atherosclerotic lesions in the internal carotid artery in 3 patients. One patient had change of operative procedure or SCP methods. As a result, 23 patients were analyzed. Twelve and 11 patients underwent total arch replacement and hemiarch replacement, respectively. The 30-day mortality rate was 0%; 1 patient

Comment

To the best of our knowledge, this is the first study to estimate ONH blood flow during RCP in thoracic aorta surgery using LSFG to monitor the cerebral circulation. The results of our study demonstrated that the cerebral microcirculation during RCP detected by LSFG was similar to moderate HCA without adjunctive strategy. Moreover, the cerebral microcirculation during SCP was significantly higher compared with simple circulatory arrest and RCP under moderate hypothermia.

A retrospective

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