Modified Technique for Retrograde Cerebral Perfusion during Hemiarch Aortic Replacement

Background Uncertainty remains regarding the optimal method of brain protection for procedures that require repair or replacement of the aortic arch. We examined the early outcomes of a technique for brain protection in patients undergoing partial aortic arch (hemiarch) replacement that involves deep hypothermic circulatory arrest (DHCA) and retrograde cerebral perfusion (RCP) of cold blood from the superior vena cava toward the end of the arrest interval. Methods During a recent 15-year interval, 520 patients underwent elective or urgent/emergent ascending aortic and hemiarch replacement as an isolated (47 patients) or combined (473 patients) procedure employing DHCA (mean nasopharyngeal temperature at circulatory arrest, 17.1°C and mean duration, 19.3 minutes) supplemented with RCP of cold blood from the superior vena cava toward the end of the arrest interval (mean, 6.7 minutes). The mean age of the patients was 59.5 years, and 65% were male. Results The in-hospital and 30-day mortality rates were 1.2% (six patients). Seven patients (1.4%) sustained a stroke and 19 patients (3.7%) had transient neurologic dysfunction that completely resolved by the time of hospital discharge. Four patients (0.77%) developed postoperative renal failure requiring dialysis. Twenty-one patients (4%) required ventilator support for >48 hours and five patients (0.96%) required a tracheostomy. The median hospital length of stay was 6 days. Conclusion DHCA with a brief interval of RCP is a safe and effective technique for brain protection during hemiarch aortic replacement. RCP reduces the duration of brain ischemia and permits removal of particulate matter and air from the arterial circulation.

Diffuse correlation spectroscopy used to monitor cerebral blood flow during adult hypothermic circulatory arrests

Real-time noninvasive monitoring of cerebral blood flow during surgery could improve the morbidity and mortality rates associated with hypothermic circulatory arrests (HCA) in adult cardiac patients. In this study, we used a combined frequency domain near-infrared spectroscopy (FDNIRS) and diffuse correlation spectroscopy (DCS) system to measure cerebral oxygen saturation (SO2) and an index of blood flow (CBFi) in 12 adults going under cardiac surgery with HCA. Our measurements revealed that a negligible amount of blood is delivered to the brain during HCA with retrograde cerebral perfusion (RCP), indistinguishable from HCA-only cases (CBFi drops of 91% ± 3% and 96% ± 2%, respectively) and that CBFi drops for both are significantly higher than drops during HCA with antegrade cerebral perfusion (ACP) (p = 0.003). We conclude that FDNIRS-DCS can be a powerful tool to optimize cerebral perfusion, and that RCP needs to be further examined to confirm its efficacy, or lack thereof.

Total body retrograde perfusion during hypothermic circulatory arrest is unsafe

Retrograde cerebral perfusion and retrograde inferior vena cava perfusion at a pressure of 25 mmHg can protect brain and visceral organs during hypothermic circulatory arrest. Total body retrograde perfusion has been proposed as an alternative during aortic arch surgery. We describe two patients who received total body retrograde perfusion during hemi-arch replacement. The procedure had to be terminated at 8 and 15 minutes due to severe fluid retention and decline in cerebral oxygen saturation. Delirium occurred in one patient after surgery. We concluded that total body retrograde perfusion may be associated with high risk of hypoperfusion and should not be recommended.