Efficacy of unilateral cerebral perfusion for brain protection in aortic arch surgery

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.

Cerebral Protection Strategies and Stroke in Surgery for Acute Type A Aortic Dissection

Background: Perioperative stroke remains a devastating complication in the operative treatment of acute type A aortic dissection. To reduce the risk of perioperative stroke, different perfusion techniques can be applied. A consensus on the preferred cerebral protection strategy does not exist. Methods: To provide an overview about the different cerebral protection strategies, literature research on Medline/PubMed was performed. All available original articles reporting on cerebral protection in surgery for acute type A aortic dissection and neurologic outcomes since 2010 were included. Results: Antegrade and retrograde cerebral perfusion may provide similar neurological outcomes while outperforming deep hypothermic circulatory arrest. The choice of arterial cannulation site and chosen level of hypothermia are influencing factors for perioperative stroke. Conclusions: Deep hypothermic circulatory arrest is not recommended as the sole cerebral protection technique. Antegrade and retrograde cerebral perfusion are today’s standard to provide cerebral protection during aortic surgery. Bilateral antegrade cerebral perfusion potentially leads to superior outcomes during prolonged circulatory arrest times between 30 and 50 min. Arterial cannulation sites with antegrade perfusion (axillary, central or carotid artery) in combination with moderate hypothermia seem to be advantageous. Every concept should be complemented by adequate intraoperative neuromonitoring.

Brain and lower body protection during aortic arch surgery

BACKGROUND

Deep hypothermic circulatory arrest (DHCA) at ≤20°C for aortic arch surgery has been widely used for decades, with or without cerebral perfusion (CP), antegrade (antegrade cerebral perfusion [ACP]), or retrograde. In recent years nadir temperature progressively increased to 26°C-28°C (moderately hypothermic circulatory arrest [MHCA]), adding ACP. Aim of this multicentric study is to evaluate early results of aortic arch surgery and if DHCA with 10 min of cold reperfusion at the same nadir temperature of the CA before rewarming (delayed rewarming [DR]) can provide a neuroprotection and a lower body protection similar to that provided by MHCA + ACP.

METHODS

A total of 210 patients were included in the study. DHCA + DR was used in 59 patients and MHCA + ACP in 151. Primary endpoints were death, neurologic event (NE), temporary (TNE), or permanent (permanent neurologic deficit [PND]), and need of renal replacement therapy (RRT).

RESULTS

Operative mortality occurred in 14 patients (6.7%), NEs in 17 (8.1%), and PNDs in 10 (4.8%). A total of 23 patients (10.9%) needed RRT. Death + PND occurred in 21 patients (10%) and composite endpoint in 35 (19.2%). Intergroup weighed logistic regression analysis showed similar prevalence of deaths, NDs, and death + PND, but need of RRT (odds ratio [OR]: 7.39, confidence interval [CI]: 1.37-79.1) and composite endpoint (OR: 8.97, CI: 1.95-35.3) were significantly lower in DHCA + DR group compared with MHCA + ACP group.

CONCLUSIONS

The results of our study demonstrate that DHCA + DR has the same prevalence of operative mortality, NE and association of death+PND than MHCA + ACP. However, the data suggests that DHCA + DR when compared with MHCA + ACP provides better renal protection and reduced prevalence of composite endpoint.

Optimal temperature management in aortic arch surgery: A systematic review and network meta-analysis

OBJECTIVES

New temperature management concepts of moderate and mild hypothermic circulatory arrest during aortic arch surgery have gained weight over profound cooling. Comparisons of all temperature levels have rarely been performed. We performed direct and indirect comparisons of deep hypothermic circulatory arrest (DHCA) (≤20°C), moderate hypothermic circulatory arrest (MHCA) (20.1-25°C), and mild hypothermic circulatory arrest (mild HCA) (≥25.1°C) in a network meta-analysis.

METHODS

The literature was systematically searched for all papers published through February 2022 reporting on clinical outcomes after aortic arch surgery utilizing DHCA, MHCA and mild HCA. The primary outcome was operative mortality. The secondary outcomes were postoperative stroke and acute kidney failure (AKI).

RESULTS

A total of 34 studies were included, with a total of 12,370 patients. DHCA was associated with significantly higher postoperative incidence of stroke when compared with MHCA (odds ratio [OR], 1.46, 95% confidence interval [CI], 1.19-1.78) and mild HCA: (OR, 1.50, 95% CI, 1.14-1.98). Furthermore, DHCA and MHCA were associated with higher operative mortality when compared with mild HCA (OR 1.71, 95% CI, 1.23-2.39 and OR 1.50, 95% CI, 1.12-2.00, respectively). Separate analysis of randomized and propensity score matched studies showed sustained increased risk of stroke with DHCA in contrast to MHCA and mild HCA (OR, 1.61, 95% CI, 1.18-2.20, p value = .0029 and OR, 1.74, 95% CI, 1.09-2.77, p value = .019).

CONCLUSIONS

In the included studies, the moderate to mild hypothermia strategies were associated with decreased operative mortality and the risk of postoperative stroke. Large-scale prospective studies are warranted to further explore appropriate temperature management for the treatment of aortic arch pathologies.

Optimal brain protection in aortic arch surgery

There is considerable debate with regard to the optimal cerebral protection strategy during aortic arch surgery. There are three contemporary techniques in use which include straight deep hypothermic circulatory arrest (DHCA), DHCA with retrograde cerebral perfusion (DHCA + RCP), and moderate hypothermic circulatory arrest with antegrade cerebral perfusion (MHCA + ACP). Appropriate application of these methods ensures appropriate cerebral, myocardial, and visceral protection. Each of these techniques has benefits and drawbacks and ensuring coordinated circulation management strategy is critical to safe performance of aortic arch surgery. In this report, we will review various cannulation strategies, review logistics of hypothermia, and review the relevant literature to outline the strengths and weaknesses of these various cerebral protection strategies.

Unilateral versus bilateral cerebral perfusion during aortic surgery for acute type A aortic dissection: a multicentre study

OBJECTIVES

The aim of this retrospective multicentre study was to investigate and compare clinical outcomes of unilateral and bilateral antegrade cerebral perfusion (ACP) strategies on cerebral protection during surgery for type A aortic dissection.

METHODS

Data from 646 patients who underwent surgical repair of thoracic type A aortic dissection using unilateral and bilateral ACP with moderate hypothermic circulatory arrest in 3 cardiac surgical institutions between 2008 and 2018 were analysed. Propensity matching was performed to assess which technique ensured better outcomes.

RESULTS

Unilateral and bilateral ACP techniques were performed in 250 (39%) and in 396 (61%) patients, respectively. Propensity score analysis identified 189 matched pairs. In the matched cohort, the lowest core temperature was 27.5°C and 28°C in the bilateral and unilateral groups, respectively (P < 0.001). The unilateral technique required significantly shorter aortic cross-clamp and cardiopulmonary bypass times than bilateral technique [82 min vs 100 min (P < 0.001); 170 min vs 195 min (P < 0.001)]. The 30-day mortality was comparable (P = 0.325). The bilateral group reported a significantly higher incidence of permanent neurologic deficits (P < 0.001), left brain hemisphere stroke (P = 0.007) and all-combined complications (P < 0.001). Ten-year survival was comparable (P = 0.45).

CONCLUSIONS

Unilateral and bilateral ACP are both valid brain protection strategies in the landscape of aortic arch surgery. While admitting all the study limitations, unilateral technique could offer some clinical advantages.

CLINICAL REGISTRATION NUMBER

76049.

Ascending aorta replacement in patients with coronary ostia localized above the sinotubular junction

OBJECTIVES

The study objective was to describe the technique and outcomes of original coronary ostial slide plasty in patients with anomalous coronary artery origin (ACAO) localized in the aneurysmal ascending aorta (AA) being replaced because of its isolated pathology and otherwise non-pathological aortic root.

METHODS

A total of 23 patients (median age 52 years) with the ascending phenotype of proximal aorta aneurysm and ACAO of at least 1 coronary artery localized in the AA being replaced underwent ostial slide plasty to transpose the ACAO to the respective sinus of Valsalva and, consequently, to allow an AA replacement with placement of the proximal anastomosis at the level of the sinotubular junction (STJ). In 15 patients, the aortic valve was bicuspid, and all but 3 patients presented with a relevant valve defect. In addition to remodelling the STJs (all patients), valve-sparing repair or replacement was performed in 12 and 8 patients, respectively.

RESULTS

No patient died during the entire follow-up (median 72, range 3-183 months). One patient required replacement of a recurrently insufficient valve that was repaired primarily using cusp patch plasty, but there were no further cardiac reoperations nor any re-interventions on the proximal aorta, aortic valve and/or coronary artery ostia. Two patients received peripheral coronary stents (8 and 7 years after surgery, respectively) due to coronary heart disease.

CONCLUSIONS

Transposition of the ACAO from the replaced AA into the normal sinus of Valsalva using the ostial slide plasty offers a simple and safe surgical option enabling a recreation of a durable STJ at the level of the anastomosis between the root and the aortic graft.

State of the Art Review: Surgical Treatment of Acute Type A Aortic Dissection

Acute type A aortic dissection (ATAAD) is a life-threatening event that requires immediate surgical treatment. Improvements in surgical treatment, graft technology, organ protection and imaging techniques have led to improved clinical outcomes. Individualized treatment concepts have emerged based on more advanced planning tools that allow for a tailored approach even in complex situations such as multi-level malperfusion. This review provides an overview of the current surgical treatment of ATAAD, focusing on new disease classifications, preoperative computed tomography angiography (CTA) assessment, new prosthesis and stent technologies, and organ-protection strategies.

Antegrade cerebral perfusion: A review of its current application

The technique of antegrade cerebral perfusion has been adopted by many aortic surgery centers as the routine method of brain protection with some variations in its implementation. These variations stem from the issues with regard to the perfusion pressure, flow, temperature, pH management, hematocrit value, cannulation sites, and unilateral versus bilateral application. In this review, the prespecified issues were discussed and some recommendations about the implementation of antegrade cerebral perfusion were given.

[Use of temporary arterial shunt in surgery of dissection of the aorta and brachiocephalic arteries]

BACKGROUND

Unsolved problems of cerebral protection in operations on the aortic arch, especially in a combination with extension of dissection to the brachiocephalic arteries determine search for variants making it possible to carry out adequate cerebral perfusion.

AIM

To propose a new technique and initial experience of using cerebral perfusion through a temporary shunt from the basin of the left subclavian artery at the stage of prosthetic repair of brachiocephalic arteries.

PATIENTS AND METHODS

At the Department of Reconstructive Surgery and Aortic Root of A.N. Bakulev National Medical Research Centre of Cardiovascular Surgery, a total of 6 patients (5 men) with type A aortic dissection underwent a stage of restoration of brachiocephalic arteries with the use of a temporary arterial shunt. The mean age was 48±15 years. The patients had chronic aortic dissection involving brachiocephalic arteries, primary fenestration in the aortic arch. All were found to have signs of chronic cerebrovascular insufficiency (dizziness, loss of consciousness); 2 patients had a history of transitory focal impairments. All patients were subjected to prosthetic repair of the ascending portion, aortic arch and all brachiocephalic arteries in conditions of adaptive perfusion with the use of adaptive loop from arterial lines. Supracoronary reconstruction of the ascending aorta was performed in 4 patients, Bentall operation in 2 subjects, with all undergoing total aortic arch replacement according to the elephant trunk technique. Brachiocephalic arteries were repaired using a trifurcated vascular grafts.

RESULTS

Mean duration of cerebral perfusion along the temporary shunt amounted to 34±12 min. At all stages of operation, the level of haemoglobin oxygen saturation (rSO2) according to cerebral oximetry was within the reference values. All patients were discharged averagely on POD 12.

CONCLUSION

A novel technique of cerebral perfusion along a temporary shunt will make it possible to extend the capabilities of heart surgeons in complicated combined interventions on the aortic arch and brachiocephalic arteries.

Complete closure of coronary fistula communicating with the descending aorta

We report a rare case of complex coronary fistula that contained two aneurysms and was connected to the descending aorta. The fistula was also associated with further aortic pathologies necessitating surgery. Preoperative computed tomography angiography, which revealed an abnormal vessel communication, was crucial for choosing the appropriate operative strategy. During a one-stage procedure comprising closure of both arterial (aortic and coronary) fistula origins and repair of the aortic valve and thoracic aorta, the coronary origin of the fistula was ligated and the frozen elephant trunk technique was used to close the aortic origin.

Goal-directed cerebral perfusion in aortic arch surgery: scientific leap or hype?

Although significant advancements in cerebral protection strategies in aortic surgery have been achieved in recent years, controversy remains on what constitutes the optimal strategy. Deep hypothermic circulatory arrest alone is a viable approach in many instances, but the need for a prolonged duration of circulatory arrest and increasing case complexity have led to the utilization of adjunctive cerebral perfusion strategies. In this review, we discuss the efficacy of deep hypothermic circulatory arrest and its limitations, the role of retrograde cerebral perfusion and unilateral and bilateral antegrade cerebral perfusion, and the trend towards goal-directed perfusion strategies, all emphasizing the pressing need for randomized clinical trials to better define the optimal strategy.

Severe systemic inflammatory response syndrome in patients following Total aortic arch replacement with deep hypothermic circulatory arrest

Background

This cohort study aims to retrospectively investigate the incidence of severe systemic inflammatory response syndrome (sSIRS) in patients following total aortic arch replacement (TAR) under deep hypothermic circulatory arrest (DHCA) with selective cerebral perfusion and its effect on clinical outcomes.

Methods

All patients who underwent TAR with DHCA were consecutively enrolled from January 2013 until December 2015 at our institute. sSIRS was diagnosed between 12 and 48 h postoperatively if patients met all four criteria of the SIRS definition.

Results

Of the 522 patients undergoing TAR with DHCA, 31.4% developed sSIRS. Patients aged under 60 yr were characterized by a higher prevalence of sSIRS (OR = 2.93; 95% CI 2.01–4.28; P <0.001). Higher baseline serum creatinine (OR = 1.61; 95% CI 1.18–2.20; P = 0.003), concomitant coronary disease (OR = 2.00; 95% CI 1.15–3.48; P = 0.015) and extended cardiopulmonary time (OR = 1.63; 95% CI 1.23–2.18; P = 0.001) independently contributed to a greater likelihood of postoperative sSIRS onset, while the preferred administration of ulinastatin (OR = 0.69; 95% CI 0.51–0.93; P = 0.015) and dexmedetomidine (OR = 0.36; 95% CI 0.23–0.56; P < 0.001) attenuated it. Patients with sSIRS had a greater risk of developing postoperative major adverse complications compared with the no sSIRS group [56.7%(93/164) vs 26.8% (96/358), P < 0.001]. sSIRS was found to be a significant risk factor for major adverse complications (OR, 4.52; 95% CI, 3.40–6.01; P < 0.001). A significant difference was revealed in in-hospital death following TAR between the sSIRS group and the no-sSIRS group [4.88% (8/164) vs 1.12% (4/358), P = 0.019]. The Kaplan-Meier curve indicated that the time to discharge from the intensive care unit was significantly prolonged in the sSIRS group compared with patients without it (log-rank p < 0.001).

Conclusions

sSIRS occurs commonly in patients following TAR with DHCA. There is an inverse association between age and sSIRS onset, whereby age over 60 yr can lower the risk of it. sSIRS development can increase the likelihood of major postoperative major adverse events.