"Drum Tower Hospital" strategy for acute type A aortic dissection with coma

OVERVIEW

Acute type A aortic dissection (ATAAD) with persistent coma is a life-threatening condition associated with high mortality and poor neurological outcomes. The optimal timing for surgical intervention in these patients remains uncertain, and many patients are not eligible for surgery due to their poor prognosis.

DESCRIPTION

In this case, a 53-year-old man with hypertension presented to the emergency department in a coma that had lasted for 9 hours. The patient was diagnosed with ATAAD and underwent the "Drum Tower Hospital" strategy, which involved preoperative assessments, including computed tomography angiography (CTA) and quantitative electroencephalogram (qEEG) monitoring. Surgical interventions, such as emergency stenting and aortic replacement, were performed to restore blood flow and repair the aorta. Postoperative monitoring, including qEEG, showed improvements in brain function. Despite the patient experiencing hemiplegia and a neurological deficit, the "Drum Tower Hospital" strategy, guided by comprehensive brain assessments, showed promise in managing ATAAD with coma. However, further research is needed to establish effective treatment strategies for these patients. Overall, ATAAD with persistent coma is a critical condition with limited treatment options. The "Drum Tower Hospital" strategy, supported by multimodal brain assessment, offers a potential approach to improve outcomes in these patients.

Cerebral Perfusion and Neuromonitoring during Complex Aortic Arch Surgery: A Narrative Review

Complex ascending and aortic arch surgery requires the implementation of different cerebral protection strategies to avoid or limit the probability of intraoperative brain damage during circulatory arrest. The etiology of the damage is multifactorial, involving cerebral embolism, hypoperfusion, hypoxia and inflammatory response. These protective strategies include the use of deep or moderate hypothermia to reduce the cerebral oxygen consumption, allowing the toleration of a variable period of absence of cerebral blood flow, and the use of different cerebral perfusion techniques, both anterograde and retrograde, on top of hypothermia, to avoid any period of intraoperative brain ischemia. In this narrative review, the pathophysiology of cerebral damage during aortic surgery is described. The different options for brain protection, including hypothermia, anterograde or retrograde cerebral perfusion, are also analyzed, with a critical review of the advantages and limitations under a technical point of view. Finally, the current systems of intraoperative brain monitoring are also discussed.

Analysis of risk factors of cerebral complications after Stanford type A aortic dissection involving arch surgery

OBJECTIVE

To explore the risk factors of cerebral neurological complications after surgery for Stanford type A aortic arch surgery.

METHODS

One hundred sixteen patients who received Stanford type A aortic dissection from January 2012 to December 2019 were recruited. All patients received surgery under deep hypothermic circulatory arrest (DHCA) and general anesthesia. They were grouped by degree of postoperative cerebral neurological complication. The related factors of cerebral neurological complications were analyzed by single-factor analysis and multi-factor logistic regression.

RESULTS

Postoperative neurological complications were observed in 31 cases (26.72 %). Two groups were identified: permanent neurological dysfunction (PND) was observed in seven cases, and temporary neurological dysfunction (TND) was observed in 24 cases. In-hospital mortality was 9.48 % (11/116), with six in the cerebral complication groups and five in the non-complication group. Single-factor analysis showed the associated factors were age, stroke history, carotid plaque or stenosis, emergency surgery, renal dysfunction, hypotension, aortic clamping time, deep hypothermic circulatory arrest time, postoperative hypoxemia, postoperative low cardiac output and plasma transfusion >800 ml, and erythrocyte suspension transfusion >6 U. Multi-factor logistic analysis showed the independent predictive factors were DHCA time >40 min, plasma transfusion >800 ml, erythrocyte suspension transfusion >6 U, history of stroke, and carotid plaque or stenosis.

CONCLUSION

The factors independently associated with neurological complications are DHCA time >40 min, plasma transfusion >800 ml, erythrocyte suspension transfusion >6 U, history of stroke, and carotid plaque or stenosis. Our findings suggest that patients with these risk factors should receive intervention during treatment to reduce cerebral neurological complications.

The History of Deep Hypothermic Circulatory Arrest in Thoracic Aortic Surgery

Depending on the extent of aortic disease and surgical repair required, thoracic aortic surgery often involves periods of reduced cerebral perfusion. Historically, this resulted in detrimental neurological dysfunction, and high risk of mortality and morbidity. Over the last half century, rapid improvements have revolutionized aortic surgery. Among these, deep hypothermic circulatory arrest (DHCA) has drastically reduced the risk of mortality and morbidity following surgery on the thoracic aorta. This progress was facilitated by experimental pioneers such as Bigelow, who studied reduced oxygen expenditure consequent on induction of hypothermia in dogs. These encouraging findings led to trials in human cardiac surgery by Lewis in 1952 and further made possible the first successful aortic arch replacement by Denton Cooley and Michael De Bakey. Modern day surgery has come a long way from the use of immersion of the patient in ice baths and other primitive techniques previously described. This paper explores the development of deep hypothermic circulatory arrest from its origins to the present.

Clinical and biochemical outcomes for additive mesenteric and lower body perfusion during hypothermic circulatory arrest for complex total aortic arch replacement surgery

Surgical repair of transverse aortic arch aneurysms frequently employ hypothermia and antegrade cerebral perfusion as protective strategies during circulatory arrest. However, prolonged mesenteric and lower limb ischemia can lead to significant lactic acidosis and end organ dysfunction, which remains a significant cause of post-operative morbidity and mortality. We report our experience with additive warm mesenteric and lower body perfusion (1-3 L/min, 30°C) in addition to continuous cerebral and myocardial perfusion in 5 patients who underwent total aortic arch replacement with trifurcated head vessel re-implantation and distal elephant trunk reconstruction. Concomitant surgical procedures included re-operations (2), aortic root operations (2), coronary artery bypass (2) and descending thoracic aortic replacement (1). Serum lactate levels demonstrated a rapid decline from a peak 9.9±2.6 post circulatory arrest to 3.4±2.0 in the intensive care unit (ICU). The lowest serum bicarbonate levels were 19.3±3.5 mmol/L, intra-operatively, which normalized to 28.4±2.4 mmol/L on return to the ICU. The lowest pH levels were 7.25±0.10, corrected to 7.43±0.04 on return to the ICU. Mean cardiopulmonary bypass and aortic cross-clamp times were 361±104 and 253±85 minutes, respectively. Mean cerebral and lower body circulatory arrest times were 0 (0) and 50±35 minutes, respectively. The mean time required for systemic rewarming was 95±66 minutes. There were no in-hospital mortalities and no patient experienced any neurological, mesenteric, renal or lower limb ischemic complications. Two patients required mechanical ventilation >24 hours, and one patient returned for reoperation for bleeding. Median intensive care unit and total hospital lengths of stay were 5 and 16 days, respectively. Our results suggest early serum lactate clearance, normalization of acidosis, and metabolic recovery when utilizing a simultaneous cerebral perfusion and warm body protection strategy for complex aortic arch surgery. This additive perfusion strategy may attenuate visceral and lower body ischemia that normally develops during periods of deep hypothermic circulatory arrest.

Evolution of cerebral perfusion techniques in type a aortic dissection surgery: a single center experience

BACKGROUND

The purpose of this study was to investigate the effect of using antegrade selective cerebral perfusion (ASCP) with moderate hypothermia on hospital mortality after surgery for acute type A aortic dissection (AAAD).

METHODS

Between January 1998 and December 2008, 142 consecutive patients were operated on for AAAD. Patients were divided into two subgroups: the cohort of patients operated on from January 1998 until December 2003 (without ASCP) (P1998-2003, n=64) and the cohort operated on from January 2004 until December 2008 (with ASCP)(P2004-2008, n=78).

RESULTS

The difference in hospital mortality was statistically significant (P1998-2003: 42.2%; P2004-2008: 14.1%, p<0.0005). Survival rates were 51.6±6.2% vs. 75.1±5.5% and 45.9±6.2% vs. 69.7±7.3% for one and four years, respectively (p=0.001). Multivariate logistic regression analysis revealed that ASCP was the only independent protective factor of hospital mortality (p=0.047).

CONCLUSION

In patients operated on for AAAD, antegrade selective cerebral perfusion with moderate hypothermia is a significant factor in decreasing hospital mortality.