Aortic arch repair using hypothermic circulatory arrest technique associated with pharmacological brain protection

2024 EACTS/EACTAIC/EBCP Guidelines on cardiopulmonary bypass in adult cardiac surgery

Clinical practice guidelines consolidate and evaluate all pertinent evidence on a specific topic available at the time of their formulation. The goal is to assist physicians in determining the most effective management strategies for patients with a particular condition. These guidelines assess the impact on patient outcomes and weigh the risk-benefit ratio of various diagnostic or therapeutic approaches. While not a replacement for textbooks, they provide supplementary information on topics relevant to current clinical practice and become an essential tool to support the decisions made by specialists in daily practice. Nonetheless, it is crucial to understand that these recommendations are intended to guide, not dictate, clinical practice, and should be adapted to each patient's unique needs. Clinical situations vary, presenting a diverse array of variables and circumstances. Thus, the guidelines are meant to inform, not replace, the clinical judgement of healthcare professionals, grounded in their professional knowledge, experience and comprehension of each patient's specific context. Moreover, these guidelines are not considered legally binding; the legal duties of healthcare professionals are defined by prevailing laws and regulations, and adherence to these guidelines does not modify such responsibilities. The European Association for Cardio-Thoracic Surgery (EACTS), the European Association of Cardiothoracic Anaesthesiology and Intensive Care (EACTAIC) and the European Board of Cardiovascular Perfusion (EBCP) constituted a task force of professionals specializing in cardiopulmonary bypass (CPB) management. To ensure transparency and integrity, all task force members involved in the development and review of these guidelines submitted conflict of interest declarations, which were compiled into a single document available on the EACTS website (https://www.eacts.org/resources/clinical-guidelines). Any alterations to these declarations during the development process were promptly reported to the EACTS, EACTAIC and EBCP. Funding for this task force was provided exclusively by the EACTS, EACTAIC and EBCP, without involvement from the healthcare industry or other entities. Following this collaborative endeavour, the governing bodies of EACTS, EACTAIC and EBCP oversaw the formulation, refinement, and endorsement of these extensively revised guidelines. An external panel of experts thoroughly reviewed the initial draft, and their input guided subsequent amendments. After this detailed revision process, the final document was ratified by all task force experts and the leadership of the EACTS, EACTAIC and EBCP, enabling its publication in the European Journal of Cardio-Thoracic Surgery, the British Journal of Anaesthesia and Interdisciplinary CardioVascular and Thoracic Surgery. Endorsed by the EACTS, EACTAIC and EBCP, these guidelines represent the official standpoint on this subject. They demonstrate a dedication to continual enhancement, with routine updates planned to ensure that the guidelines remain current and valuable in the ever-progressing arena of clinical practice.

Perioperative electroencephalography in cardiac surgery with hypothermic circulatory arrest: a narrative review

OBJECTIVES

Cardiac surgery with hypothermic circulatory arrest (HCA) is associated with neurological morbidity of variable severity and electroencephalography (EEG) is a sensitive proxy measure of brain injury. We conducted a narrative review of the literature to evaluate the role of perioperative EEG monitoring in cardiac surgery involving HCA.

METHODS

Medline, Embase, Central and LILACS databases were searched to identify studies utilizing perioperative EEG during surgery with HCA in all age groups, published since 1985 in any language. We aimed to compare EEG use with no use but due to the lack of comparative studies, we performed a narrative review of its utility. Two or more reviewers independently screened studies for eligibility and extracted data.

RESULTS

Fourty single-centre studies with a total of 3287 patients undergoing surgery were identified. Most were observational cohort studies (34, 85%) with only 1 directly comparing EEG use with no use. EEG continuity (18, 45%), seizures (15, 38%) and electrocerebral inactivity prior to circulatory arrest (15, 38%) were used to detect, monitor, prevent and prognose neurological injury. Neurological dysfunction was reported in almost all studies and occurred in 0-21% of patients. However, the heterogeneity of reported clinical and EEG outcome measures prevented meta-analysis.

CONCLUSIONS

EEG is used to detect cortical ischaemia and seizures and predict neurological abnormalities and may guide intraoperative cerebral protection. However, there is a lack of comparative data demonstrating the benefit of perioperative EEG monitoring. Use of a standardized methodology for performing EEG and reporting outcome metrics would facilitate the conduct of high-quality clinical trials.

Brain Protection in Aortic Arch Surgery: An Evolving Field

Despite advances in cardiac surgery and anesthesia, the rates of brain injury remain high in aortic arch surgery requiring circulatory arrest. The mechanisms of brain injury, including permanent and temporary neurologic dysfunction, are multifactorial, but intraoperative brain ischemia is likely a major contributor. Maintaining optimal cerebral perfusion during cardiopulmonary bypass and circulatory arrest is the key component of intraoperative management for aortic arch surgery. Various brain monitoring modalities provide different information to improve cerebral protection. Electroencephalography gives crucial data to ensure minimal cerebral metabolism during deep hypothermic circulatory arrest, transcranial Doppler directly measures cerebral arterial blood flow, and near-infrared spectroscopy monitors regional cerebral oxygen saturation. Various brain protection techniques, including hypothermia, cerebral perfusion, pharmacologic protection, and blood gas management, have been used during interruption of systemic circulation, but the optimal strategy remains elusive. Although deep hypothermic circulatory arrest and retrograde cerebral perfusion have their merits, there have been increasing reports about the use of antegrade cerebral perfusion, obviating the need for deep hypothermia. With controversy and variability of surgical practices, moderate hypothermia, when combined with unilateral antegrade cerebral perfusion, is considered safe for brain protection in aortic arch surgery performed with circulatory arrest. The neurologic outcomes of brain protection in aortic arch surgery largely depend on the following three major components: cerebral temperature, circulatory arrest time, and cerebral perfusion during circulatory arrest. The optimal brain protection strategy should be individualized based on comprehensive monitoring and stems from well-executed techniques that balance the major components contributing to brain injury.

Deep Hypothermia and Circulatory Arrest in Adults

Brain protection during cardiopulmonary bypass has been the subject of intense research. Deep hypothermic circulatory arrest (DHCA) continues to be used for that goal during complex aortic arch and large intracranial aneurysm surgeries. The anesthetic management for adult patients undergoing these types of procedures requires specific knowledge and expertise. Based on our experience and review of the current literature, the authors highlight the key areas of the anesthetic plan, discussing the risk factors associated with adverse neurologic outcome as well as the rationale for decisions regarding specific monitors and medications. In the conclusion an anesthetic protocol for adult patients undergoing DHCA is suggested.

Does the use of thiopental provide added cerebral protection during deep hypothermic circulatory arrest?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was: Does the use of thiopental provide added cerebral protection during deep hypothermic circulatory arrest (DHCA)? Altogether, more than 62 papers were found using the reported search, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Four of the seven papers used thiopental alongside other neuroprotective methods and agents. The methods included the use of ice packs to the head and core systemic hypothermia. Agents used alongside thiopental included nicardipine and mannitol. Thiopental was found to have the ability to lower oxygen consumption, where oxygen consumption was measured using the phosphocreatinine and adenosine triphosphate ratio. The neuroprotective effect of thiopental was evaluated by assessing the electrical activity of the brain during circulatory arrest, by which it was shown to be advantageous. However, other trials suggested that adding thiopental during circulatory arrest did not provide any extra protection to the brain. The timing of thiopental administration is of importance in order to gain positive outcomes, as it's ability to lower the cerebral energy state may result in unfavourable results if added before hypothermic circulatory arrest, where this may lead to an ischaemic event. We conclude that the use of thiopental during deep hypothermic circulatory arrest is beneficial, but if administered too early, it may replete the cerebral energy state before arrest and prove to be detrimental.

Continuous cerebral and myocardial perfusion during one-stage repair for aortic coarctation with ventricular septal defect

Controversy still exists concerning the use of deep hypothermic circulatory arrest (DHCA) and selective antegrade cerebral perfusion (SACP) for repair of aortic coarctation (CoA) with ventricular septal defect (VSD). This report therefore describes outcomes of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia compared with DHCA and SACP. Retrospective analysis was performed for 110 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Patients repaired under CCMP with mild hypothermia (32 °C) (group A, n = 60) were compared with those repaired under DHCA (18 °C) and SACP (group B, n = 50). In group A, the single arterial cannula perfusion technique was used for 15 patients (25 %), and the dual arterial cannula perfusion technique was used for 45 patients (75 %). The preoperative data were similar in the two groups. Group A had no hospital mortalities, compared with two mortalities (4 %) in group B. Group A had shorter myocardial ischemic and cardiopulmonary times, fewer delayed sternal closures, a shorter time to extubation, lower postoperative lactate levels, and fewer patients with low cardiac output requiring extracorporeal membrane oxygenation or with multiorgan failure than group B. During the postoperative course, no clinical or electrical neurologic events occurred in either group. The mean follow-up period was 5.2 ± 3.2 years for group A and 7.5 ± 3.1 years for group B (P = 0.048). One late death occurred in group B and no late deaths in group A. The actuarial survival for the two groups was similar (100 % for group A vs 96 % for group B; P = 0.264). The freedom from all types of cardiac reintervention was 96.7 % in group A and 89.6 % in group B (P = 0.688). All the patients were free of neurologic symptoms. The authors' perfusion strategy using CCMP with mild hypothermia for repair of CoA with VSD is feasible, safe, and associated with improved postoperative recovery and should be the method of choice.

Outcome of continuous cerebral and myocardial perfusion under mild hypothermia for aortic coarctation with ventricular septal defect repair

BACKGROUND

Controversy still exists on the use of the optimal cardiopulmonary bypass (CPB) management in aortic coarctation (CoA) with ventricular septal defect (VSD) repair. We report the outcome of patients undergoing continuous cerebral and myocardial perfusion (CCMP) under mild hypothermia.

METHOD

This is a retrospective analysis of 60 consecutive patients undergoing anatomic reconstruction of CoA with VSD closure between 1999 and 2011. Single arterial cannula perfusion technique was used in 15 (25%) patients, and a dual arterial cannula perfusion technique was used in 45 (75%) patients.

RESULTS

There were no hospital or late mortalities. Average CPB time was 105 ± 28 minutes, aortic clamp 27 ± 7 minutes, and descending aortic cross-clamp time 24 ± 5 minutes. Average continuous cerebral perfusion flow was 64 ± 8 mL/kg per minute. No patient needed delayed sternal closure. Average duration of ventilation was 38 ± 20 hours, ICU stay 7 ± 3 days, and hospital stay 14 ± 6 days. No patient required revision for bleeding and/or extracorporeal membrane oxygenation support. No neurologic complications were noted.

CONCLUSION

A perfusion strategy using CCMP with mild hypothermia for CoA and VSD repair is feasible and safe.

Managing Emergency Hypertension in Aortic Dissection and Aortic Aneurysm Surgery

From a disease that just a few decades ago carried an ominous prognosis, aortic dissection has become a highly treatable condition. Similar development has occurred in regard to the treatment of thoracic aortic aneurysms. Treatment options are medical, surgical, or endovascular. Aortic dissection always presents as a hypertensive emergency and requires parenteral antihypertensive agents to control blood pressure (BP) and prevent target organ damage. Diligent control of BP is of utmost importance in order to stop the progression of dissection with possible aortic branch malperfusion. Treatment for hypertensive emergency begins in the intensive care unit and continues during and after surgery. Improved surgical techniques as well as newer, safer agents that reduce BP to acceptable levels have reduced the risk of mortality and improved prognosis in the postoperative period. Nevertheless, mortality rates remain high, and successful management of aortic dissection and aortic aneurysm still poses a clinical challenge.

Time and risk analysis for acute type A aortic dissection surgery performed by hypothermic circulatory arrest, cerebral perfusion, and open distal aortic anastomosis

BACKGROUND

Hypothermic total circulatory arrest, retrograde or antegrade cerebral perfusion, and open distal anastomosis are important stages of surgical management and cerebral protection for acute type A dissections. Among the factors that influence survival are the transfer time to hospital from the onset of symptoms, in-hospital transfer time to operation, organ malperfusion, preoperative risk factors, and intraoperative variables. The aim of this study was to analyze time and risk factors during surgical management.

METHODS

Between September 1996 and March 2002, a total of 26 patients with acute type A aortic dissection were operated. Sixteen patients (61.5%) were male and mean age was 49 ( 13.1 years (range: 26-68). The diagnosis was based on clinical examination, telecardiography, transthoracic echocardiography, computerized tomography, and angiography. Hypothermic total circulatory arrest, retrograde or antegrade cerebral perfusion and open distal anastomosis were used during the procedures. Operative techniques were as follows: supracoronary ascending aortic replacement (17 patients), aortic root and ascending aortic replacement with flanged composite grafting technique (5 patients), replacement of ascending aorta and hemiarcus (1 patient), aortic root and ascending aortic replacement with modified Bentall technique (1 patient), replacement of ascending aorta and arcus (1 patient), and total arcus replacement with elephant trunk technique and modified Bentall procedure (1 patient).

RESULTS

The early postoperative mortality rate within the first 30 days was 26.9%, and the late postoperative mortality rate was 15.8%. Two patients (7.7%) developed major neurological complications during the postoperative period. Time to admission, durations of total circulatory arrest, cross-clamp, cardiopulmonary bypass, and intubation were longer, and postoperative blood loss was greater in patients who died during early postoperative period, although the differences did not reach statistical significance. Duration of total circulatory arrest was longer in patients who developed neurological dysfunction compared to patients without this complication; this difference also did not reach statistical significance.

CONCLUSIONS

Total circulatory arrest, cerebral perfusion, and open distal anastomosis are reliable options in the surgical management of acute type A aortic dissections. With open distal anastomosis aortic arcus can be evaluated, distal anastomosis can be performed more easily, and postoperative neurological recovery is hastened. In the present study, although statistical significance could not be reached due to limited sample size, the time to admission, durations of total circulatory arrest, cross-clamp, and cardiopulmonary bypass, and the amount of postoperative chest output seem to influence postoperative survival.