Mild hypothermic circulatory arrest with selective cerebral perfusion in open arch surgery

Impact of mild hypothermic circulatory arrest on surgical outcomes in acute type a aortic dissection patients: a single-centre study

BACKGROUND

As hypothermic circulatory arrest (HCA) is being more frequently induced in patients undergoing aortic arch surgery, its safety at different degrees has become a crucial area of study. The aim of this study was to assess the surgical outcomes of mild hypothermic circulatory arrest (MI-HCA) during aortic arch surgery.

METHODS

Acute type A aortic dissection (ATAAD) patients who underwent total arch replacement (TAR) and frozen elephant trunk (FET) surgery between January 2014 and December 2023 were enrolled in this study. The patients were divided into two groups according to the minimum nasopharyngeal temperature: the moderate hypothermic circulatory arrest (MHCA) group (20-28 °C) and the MI-HCA group (> 28 °C). The inverse probability of treatment weighting (IPTW) was used to balance differences in the baseline characteristics. Perioperative variables were analysed via pairwise comparisons, multivariable logistic regression, and subgroup forest plots to assess the impact of MI-HCA on surgical outcomes.

RESULTS

A total of 447 patients were included in this study, and the mean minimum nasopharyngeal temperature was 24.80 (23.98, 27.30) °C in the MHCA group and 30.10 (29.80, 30.70) °C in the MI-HCA group. The incidence of acute kidney injury (AKI) in the MI-HCA group was lower than that in the MHCA group (52% vs. 78%, p < 0.01). In the multivariable logistic regression analysis, MI-HCA was identified as an independent protective factor for AKI (OR = 0.354, 95% CI 0.177-0.689; p = 0.003). Additionally, compared with MHCA, MI-HCA was not associated with an increased incidence of stroke, spinal cord injury, or in-hospital mortality. After IPTW, the preoperative and intraoperative data of the patients were balanced, and the incidence of AKI in the MI-HCA group was still lower than that in the MHCA group (83.26% vs. 53.61%, p = 0.004). The subgroup forest plot also demonstrated that MI-HCA was a protective factor for postoperative AKI.

CONCLUSIONS

The surgical outcomes of MI-HCA in ATAAD patients were satisfactory. Compared with MHCA, MI-HCA provided sufficient protection for distal organs, the brain, and the spinal cord, with a significantly lower incidence of AKI. These results indicate that MI-HCA could be a better approach for ATAAD surgery.

Short-term outcomes of mild (≥30 ℃) vs. moderate hypothermic circulatory arrest in aortic arch surgery

Background

Hypothermia and antegrade cerebral perfusion (ACP) strategies in open aortic arch surgery (AAS) have improved significantly. The significance of the gradual temperature rise to mild hypothermia is quite apparent, however, its safety remains a challenge. Therefore, our objective was to explore the safety and efficacy of mild hypothermic circulatory arrest (Mi-HCA, ≥30 ℃).

Methods

This retrospective cohort study enrolled in a total of 372 patients, and was performed at the Beijing Anzhen Hospital between January 2017 and November 2022. Among the 372 patients, 81 received AAS at ≥30 ℃, and the remaining 291 received the same at 22-29.9 ℃. Most acute type A aortic dissection (ATAAD) patients received total arch replacement (TAR) and frozen elephant trunk (FET) operation.

Results

Mi-HCA patients exhibited strongly augmented systemic temperature (26.19±1.63 vs. 31.40±0.79 ℃, P<0.01). The surgical, cardiopulmonary bypass (CPB), cross-clamp, circulatory arrest, and ACP durations were drastically diminished among Mi-HCA patients (all P<0.01). Moreover, the major adverse events (MAEs) incidence of Mi-HCA patients was significantly decreased (25.43% vs. 14.81%, P<0.05). Simultaneously, the Mi-HCA strategy also exhibited enhanced protection of blood cells, as well as myocardial and hepatic function. Nevertheless, multivariate logistic regression analysis revealed that Mi-HCA strategy (≥30 ℃) was not a stand-alone risk factor for MAEs following AAS.

Conclusions

The short-term outcomes and safety of Mi-HCA, in combination with ACP, in AAS are satisfactory. Additionally, relative to the traditional moderate hypothermic circulatory arrest (MHCA) approach, it can substantially decrease operation duration while improving patient clinical outcomes.

A comparison of bilateral and unilateral cerebral perfusion for total arch replacement surgery for non-marfan, type A aortic dissection

OBJECTIVES

Acknowledging lacking of consensus exist in total aortic arch (TAA) surgery for acute type A aortic dissection (AAD), this study aimed to investigate the neurologic injury rate between bilateral and unilateral cerebrum perfusion on the specific population.

METHODS

A total of 595 AAD patients other than Marfan syndrome receiving TAA surgery since March 2013 to March 2022 were included. Among them, 276 received unilateral cerebral perfusion (via right axillary artery, RCP) and 319 for bilateral cerebral perfusion (BCP). The primary outcome was neurologic injury rate. Secondary outcomes were 30-day mortality, serum inflammation response (high sensitivity C reaction protein, hs-CRP; Interleukin-6, IL-6; cold-inducible RNA binding protein, CIRBP) and neuroprotection (RNA-binding motif 3, RBM3) indexes.

RESULTS

The BCP group reported a significantly lower permanent neurologic deficits [odds ratio: 0.481, Confidence interval (CI): 0.296-0.782, p = 0.003] and 30-day mortality (odds ratio: 0.353, CI: 0.194-0.640, p < 0.001) than those received RCP treatment. There were also lower inflammation cytokines (hr-CRP: 114 ± 17 vs. 101 ± 16 mg/L; IL-6: 130 [103,170] vs. 81 [69,99] pg/ml; CIRBP: 1076 [889, 1296] vs. 854 [774, 991] pg/ml, all p < 0.001), but a higher neuroprotective cytokine (RBM3: 4381 ± 1362 vs 2445 ± 1008 pg/mL, p < 0.001) at 24 h after procedure in BCP group. Meanwhile, BCP resulted in a significantly lower Acute Physiology, Age and Chronic Health Evaluation (APACHE) Ⅱscore (18 ± 6 vs 17 ± 6, p < 0.001) and short stay in intensive care unit (4 [3,5] vs. 3 [2,3] days, p < 0.001) and hospital (16 ± 4 vs 14 ± 3 days, p < 0.001).

CONCLUSIONS

This present study indicated that BCP compared with RCP was associated with lower permanent neurologic deficits and 30-day mortality in AAD patients other than Marfan syndrome receiving TAA 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.

Clinical outcomes of mild versus moderate hypothermic circulatory arrest with antegrade cerebral perfusion in adult aortic arch surgery: A systematic review and meta-analysis

OBJECTIVES

In adult aortic arch surgery, moderate hypothermic circulatory arrest (HCA) with selective antegrade cerebral perfusion (SACP) (MoHACP) is widely used, but the application of mild HCA with SACP (MiHACP) is still controversial. This meta-analysis aimed to compare clinical outcomes using MiHACP or MoHACP.

METHODS

Studies comparing outcomes of MiHACP or MoHACP in adult aortic arch surgery were searched from four databases from inception through April 2022. Primary outcomes were postoperative permanent neurological deficit (PND), temporary neurological deficit (TND), and mortality. Secondary outcomes included other common complications. Meta-analysis was conducted using a random-effects model in all cases.

RESULTS

Eleven comparative studies were included, with 1555 patients in MiHACP group and 1499 patients in MoHACP group, and the mean HCA temperature were 29.4°C and 24.8°C, respectively. Postoperative PND, TND, mortality, paraplegia, dialysis, tracheotomy, reexploration for bleeding, and chest tube drainage volume were comparable in the two groups (p > 0.05). Ventilator time, intensive care unit and in-hospital length of stay were shorter in MiHACP group (p < 0.05). Outcomes were also comparable or had some benefits in MiHACP group when subgroup analyses were conducted according to hemiarch or total arch replacement, unilateral or bilateral SACP, HCA time, emergency aortic dissection surgery, and concomitant procedure.

CONCLUSION

The present meta-analysis showed acceptability of MiHACP in adult aortic arch surgery. Results need to be taken with caution as moderate risk of bias and very low quality of evidence were observed in this meta-analysis. Randomized controlled trials are needed for further analysis.

Cerebral protection strategies for type A aortic dissection repair

Importance

Techniques to preserve neurological function during type A aortic dissection repairs have been broadly discussed in the literature and heavily debated. Despite the effectiveness of various approaches, a consensus lacks on how to maintain optimal cerebral temperature during surgery. This review examines the three predominant cerebral protection strategies in aortic arch reconstructions: straight deep hypothermic circulatory arrest (sDHCA), retrograde cerebral perfusion (RCP), and antegrade cerebral perfusion (ACP).

Observations

The signature characteristics of sDHCA, RCP, and ACP are similar-hypothermia, with or without cerebral perfusion. Employing cerebral perfusion techniques may prolong operative times, while ACP permits operation at higher body temperatures, albeit with restricted operative durations.

Conclusion

For type A dissection arch reconstructions, sDHCA, RCP, and ACP can be successfully implemented. Factors such as operative times and individual patient conditions should be considered when choosing a cerebral protection strategy.

Temperature analysis of aortic repair with hypothermic circulatory arrest to quantify the injury by cooling

OBJECTIVES

We analyzed the temperature in proximal aortic repair with moderate hypothermic circulatory arrest (HCA) and evaluated the effect of the cooling status on postoperative outcomes.

METHODS

A total of 340 patients who underwent elective ascending aortic replacement or total arch replacement with moderate HCA from December 2006 to January 2021 were studied. The change in body temperature trends recorded during surgery was shown graphically. Several parameters, such as the nadir temperature, cooling speed and the degree of cooling (cooling area), which was the area under curve of inverted temperature trends from cooling to rewarming as calculated by the integral method, were analyzed. The relationships between these variables and a major adverse outcome (MAO) postoperatively defined as prolonged ventilation (>72 h), acute renal failure, stroke, reoperation for bleeding, deep sternal wound infection or in-hospital death were evaluated.

RESULTS

An MAO was observed in 68 patients (20%). The cooling area was larger in the MAO group than in the non-MAO group (1668.7 vs 1383.2°C min; P < 0.0001). A multivariate logistic model showed that old myocardial infarction, peripheral vascular disease, chronic renal dysfunction, cardiopulmonary bypass time and the cooling area were independent risk factors for an MAO (odds ratio = 1.1 per 100°C min; P < 0.001).

CONCLUSIONS

The cooling area, which indicates the degree of cooling, shows a significant relationship with an MAO after aortic repair. This finding indicates that the cooling status with HCA can affect clinical outcomes.