Long-Term Survival and Quality of Life After Hypothermic Circulatory Arrest in Aortic Surgery

Optimization of Hypothermic Protocols for Neurocognitive Preservation in Aortic Arch Surgery: A Literature Review

Shifts from deep to moderate hypothermic circulatory arrest (HCA) in aortic arch surgery necessitate an examination of their differential impacts on neurocognitive functions, especially structured verbal memory, given its significance for patient recovery and quality of life. This study evaluates and synthesizes evidence on the effects of deep (≤20.0 °C), low-moderate (20.1-24.0 °C), and high-moderate (24.1-28.0 °C) hypothermic temperatures on structured verbal memory preservation and overall cognitive health in patients undergoing aortic arch surgery. We evaluated the latest literature from major medical databases such as PubMed and Scopus, focusing on research from 2020 to 2024, to gather comprehensive insights into the current landscape of temperature management during HCA. This comparative analysis highlights the viability of moderate hypothermia (20.1-28.0 °C), supported by recent trials and observational studies, as a method to achieve comparable neuroprotection with fewer complications than traditional deep hypothermia. Notably, low-moderate and high-moderate temperatures have been shown to support substantial survival rates, with impacts on structured verbal memory preservation that necessitate careful selection based on individual surgical risks and patient profiles. The findings advocate for a nuanced approach to selecting hypothermic protocols in aortic arch surgeries, emphasizing the importance of tailoring temperature management to optimize neurocognitive outcomes and patient recovery. This study fills a critical gap in the literature by providing evidence-based recommendations for temperature ranges during HCA, calling for ongoing updates to clinical guidelines and further research to refine these recommendations. The implications of temperature on survival rates, complications, and success rates underpin the necessity for evolving cardiopulmonary bypass techniques and cerebral perfusion strategies to enhance patient outcomes in complex cardiovascular procedures.

Use of duplex echoencephalography to evaluate brain death in children: A novel approach to the diagnosis

BACKGROUND AND PURPOSE

Brain death is defined as the irreversible cessation of brain function with a known etiology. This study aims to establish the value of duplex echoencephalography (DEG) in children fulfilling clinical brain death diagnostic criteria.

METHODS

DEG must show intracranial brain structures. Power Doppler is used to assess venous flow when feasible. Color Doppler patterns in all major arteries are assessed. Spectral analysis of arterial flow is divided into four grades: grade 1: inverted flow during entire diastole with time average peak velocity (TAPV) less or equal to zero; grade 2: disappearance of the inverted diastolic flow at the end of diastole; grade 3: oscillating pattern in early diastole; and grade 4: no diastolic flow with systolic blip. To fulfill diagnosis of brain death, brain perfusion must be lost for 30 minutes.

RESULTS

DEG is performed in 41 pediatric patients. In infants, loss of venous flow occurs regardless of the etiology. Grade 1 is the most common arterial color flow pattern and TAPV is always below zero. A pulsatile color flow is associated with three other types of flow patterns (grades 2-4). TAPV is not calculated, when there is loss of diastolic flow. Diagnosis of brain death is validated using nuclear brain scan in 4 patients. Two have a grade 1 flow pattern, while the other two have a grade 4 flow pattern.

CONCLUSIONS

In children, DEG following a strict protocol can be used to confirm diagnosis of brain death in the appropriate clinical setting.

Effect of moderate hypothermic circulatory arrest on neurological outcomes in elderly patients undergoing replacement of the thoracic aorta

BACKGROUND

Various studies evaluated the relationship between hypothermic circulatory arrest and neurological outcome in patients undergoing replacement of ascending aorta. The current analysis focuses on the effect of moderate hypothermic circulatory arrest (MHCA) on elderly patients. The aim of our study was to evaluate the impact of MHCA on neurological outcomes in elderly patients undergoing replacement of the ascending aorta.

RESULTS

We retrospectively analyzed 905 consecutive patients, who underwent elective replacement of ascending aorta in MHCA (24 ± 2 °C, nasopharyngeal) between 2001 and 2015. Patients with acute aortic dissection were excluded from this study. Patients were divided into two groups: those aged 75 years and older (elderly group 22.4%, n = 203) and those younger than 75 years (younger group 77.6%, n = 702). The average age was 63.2 ± 10.2 in the young group vs. 78.7 ± 3.0 years in elderly group (p < 0.001). The elderly group had a significantly higher EuroSCORE II [26.7% (18.1, 36.3) vs. 11.6% (7.4, 19.9); p < 0.001)]. The incidence of coronary heart disease (49.8% vs. 35.6%, p < 0.001) and chronic renal failure (17.2% vs. 9.1%, p = 0.001) was significantly higher in the elderly group. Intraoperatively, the time of MHCA [14 min (12, 17) vs. 15 min (12, 18); p = 0.42], cardiopulmonary bypass [139 min (110, 183) vs. 144 min (113, 189); p = 0.225], and cross-clamping [91 min (63, 116) vs. 92 min (65, 127); p = 0.348] was similar in both groups. Postoperatively, a higher incidence of delirium was significantly reported in the elderly group (24.1% vs. 9.0%, p < 0.001). However, there was no significant difference regarding neurological complications between both groups. A 30-day mortality was acceptable for the elderly group, but significantly higher compared with the younger group (7.1% vs. 3.5%, p = 0.031).

CONCLUSIONS

Our study suggests that surgical replacement of the ascending aorta in MHCA can also be applied safely in elderly patients without increasing the risk of severe neurological complications.