Antegrade or Retrograde Cerebral Perfusion in Ascending Aorta and Hemiarch Surgery? A Propensity-Matched Analysis

First-in-men experience with a novel frozen elephant trunk prosthesis featuring an endovascular side branch for left subclavian artery connection

OBJECTIVES

The objective of this study was to enhance the efficiency of aortic arch replacement through the development of a novel frozen elephant trunk (FET) prosthesis with an endovascular side branch for left subclavian artery (LSA) connection. After successful pre-clinical testing, the feasibility and safety of implementing this innovative prosthesis in human subjects were investigated.

METHODS

Between September 2020 and September 2021, 4 patients (mean age 67) with conditions such as penetrating ulcer, non A-non B aortic dissection and chronic arch aneurysm underwent surgery utilizing the customized device. Surgeries were performed under high moderate hypothermia (27°C), employing bilateral selective antegrade cerebral perfusion (SACP) and distal aortic perfusion. Anastomosis of the FET prosthesis with the aortic arch occurred in zone 1, followed by separate reimplantation of the left common carotid artery and the brachiocephalic artery.

RESULTS

All patients were discharged in good clinical condition. The mean aortic cross-clamp, antegrade selective cerebral perfusion and distal aortic perfusion times were 111, 71 and 31 min, respectively. Endovascular extension of the side branch for the LSA was required in all cases to prevent endoleak formation. One patient received a stent graft extension at the end of the operation, while 2 others underwent the procedure during their hospital stay. One patient was diagnosed with an endoleak at the first follow-up after 3 months, and endoleak sealing was achieved via the brachial artery with an extension stent graft.

CONCLUSIONS

Preliminary clinical outcomes suggest that the newly designed FET prosthesis shows promise in simplifying total arch replacement. These initial findings provide a foundation for planned clinical studies to further assess the effectiveness of this modified surgical hybrid graft, with particular attention to the length and diameter of the LSA sidearm.

Prediction of acute kidney injury incidence following acute type A aortic dissection surgery with novel biomarkers: a prospective observational study

BACKGROUND

Acute kidney injury (AKI) is a prevalent complication following acute type A aortic dissection (ATAAD) surgery and is closely associated with unfavorable prognostic outcomes. Hence, the development of a robust and efficient diagnostic approach to identify high-risk patients is of paramount importance.

METHODS

We conducted a prospective study involving 328 patients who underwent ATAAD surgery at our institution, comprising three distinct cohorts. In addition, 52 patients undergoing alternative cardiopulmonary surgeries and 37 healthy individuals were enrolled as control groups. Employing proteomic analysis, we initially identified plasma proteins potentially linked to AKI occurrence within the plasma proteomic cohort. Subsequent validation was performed in an independent cohort. Utilizing predictors derived from multivariate logistic regression analysis, a nomogram was meticulously formulated and its efficacy was validated in the model construction cohort.

RESULTS

Proteomics revealed significant elevation of plasma levels of S100A8/A9, pentraxin 3 (PTX3), and chitinase 3-like 1 (CHI3L1) immediately post-surgery in patients who developed ATAAD surgery-associated AKI (ASA-AKI). Receiver operating characteristic (ROC) curves demonstrated impressive predictive performance of S100A8/A9, PTX3, and CHI3L1 at 0 h post-surgery, yielding area under the curve (AUC) values of 0.823, 0.786, and 0.803, respectively, for ASA-AKI prediction. Furthermore, our findings exhibited positive correlations between plasma levels of S100A8/A9, PTX3, CHI3L1, and urinary neutrophil gelatinase-associated lipocalin (NGAL) at 0 h post-surgery, along with correlations between plasma S100A8/A9, CHI3L1 levels, and the Cleveland Clinic score. A logistic regression model incorporating plasma S100A8/A9, PTX3, CHI3L1 levels, urinary NGAL levels, and the Cleveland Clinic score facilitated the construction of a predictive nomogram for ASA-AKI. This nomogram demonstrated robust discriminative ability, achieving an AUC of 0.963 in the model construction cohort.

CONCLUSIONS

Our study underscored the augmentation of plasma S100A8/A9, PTX3, and CHI3L1 levels immediately post-surgery in patients developing ASA-AKI. The incorporation of these three biomarkers, in conjunction with the Cleveland Clinic score and NGAL, into a nomogram demonstrated commendable predictive efficacy. This presents a practical tool for identifying patients at an elevated risk of AKI following ATAAD surgery.

Hypothermic Circulatory Arrest in Adult Aortic Arch Surgery: A Review of Hypothermic Circulatory Arrest and its Anesthetic Implications

Diseases affecting the aortic arch often require surgical intervention. Hypothermic circulatory arrest (HCA) enables a safe approach during open aortic arch surgeries. Additionally, HCA provides neuroprotection by reducing cerebral metabolism and oxygen requirements. However, HCA comes with significant risks (eg, neurologic dysfunction, stroke, and coagulopathy), and the cardiac anesthesiologist must completely understand the surgical techniques, possible complications, and management strategies.

Innominate artery direct cannulation provides brain protection during total arch replacement for acute type A aortic dissection

Background

This study aimed to investigate the safety of direct innominate arterial (IA) cannulation using a pediatric arterial cannula to establish selective antegrade cerebral perfusion (ACP) during total arch replacement (TAR) for acute Stanford type A aortic dissection (ATAAD).

Methods

This retrospective study included patients with ATAAD who underwent TAR with the frozen elephant trunk (FET) technique between October 2020 and November 2021. Patients treated with direct IA cannulation using a pediatric arterial cannula for selective anterograde cerebral perfusion were included in the study.

Results

Of the 29 patients, 24 (82.8%) were male. The average age was 50.9 ± 9.47 years. Proximal repair included aortic root plasty (27 patients, [93.1%]) and Bentall surgery (2 patients, [6.9%]). Perioperative mortality and stroke rates were 3.4% and 6.9%, respectively. The mean lowest core temperature was 23.8 ± 0.74 °C and the mean ACP time was 25 ± 6.4 min. The aortic cross-clamp and cardiopulmonary bypass times were 141 ± 28 and 202 ± 29 min, respectively. There were no cases of IA injuries.

Conclusion

Direct IA cannulation using a pediatric arterial cannula is a simple, safe, and effective technique for establishing ACP during TAR with the FET technique for ATAAD and can avoid the potential complications of axillary artery cannulation.

Duration of deep hypothermic circulatory arrest for aortic arch surgery: is it a myth, fiction, or scientific leap?

INTRODUCTION

The use of deep hypothermic circulatory arrest (DHCA) to provide aortic surgeons with a bloodless operative field while simultaneously protecting the brain and peripheries from ischemic damage revolutionized cardiac and aortic surgery, and is currently used in specialist centers across the globe. However, it is associated with manifold adverse outcomes, including neurocognitive dysfunction and mortality. This review seeks to analyze the relationship between DHCA duration and clinical outcome, and evaluate the controversies and limitations surrounding its use.

EVIDENCE ACQUISITION

We performed a review of available literature with statistical analysis to evaluate the relationship between DHCA duration (<40 min and >40 min) and key clinical outcomes, including mortality, permanent and temporary neurological deficit, renal damage, admission length, and reintervention rate. The controversies surrounding DHCA use and future directions for care are also explored.

EVIDENCE SYNTHESIS

Statistical analysis revealed no significant association (P>0.05) between DHCA duration and clinical outcomes (early and late mortality rates, neurological deficit, admission length, and reintervention rate), both with and without adjunctive perfusion techniques.

CONCLUSIONS

Available literature suggests that the relationships between DHCA duration (with and without adjunctive perfusion) and clinical outcomes are unclear, and at present not statistically significant. Alternative surgical and endovascular techniques have been identified as promising novel approaches not requiring DHCA, as have the use of biomarkers to enable early diagnosis and intervention for aortic pathologies.

Surgical outcomes of DeBakey type I and type II acute aortic dissection: a propensity score-matched analysis in 599 patients

Background

The DeBakey classification divides Stanford acute type A aortic dissection (ATAAD) into DeBakey type I (D1) and type II (D2) according to the extent of acute aortic dissection (AAD). This retrospective study aimed to compare the early and late outcomes of D1-AAD and D2-AAD through a propensity score-matched analysis.

Methods

Between January 2009 and April 2020, 599 consecutive patients underwent ATAAD repair at our institution, and were dichotomized into D1 (n = 543; 90.7%) and D2 (n = 56; 9.3%) groups. Propensity scoring was performed with a 1:1 ratio, resulting in a matched cohort of 56 patients per group. The clinical features, postoperative complications, 5-year cumulative survival and freedom from reoperation rates were compared.

Results

In the overall cohort, the D1 group had a lower rate of preoperative shock and more aortic arch replacement with longer cardiopulmonary bypass time. The D1 group had a higher in-hospital mortality rate than the D2 group in overall (15.8% vs 5.4%; P = 0.036) and matched cohorts (19.6% vs 5.4%; P = 0.022). For patients that survived to discharge, the D1 and D2 groups demonstrated similar 5-year survival rates in overall (77.0% vs 85.2%; P = 0.378) and matched cohorts (79.1% vs 85.2%; P = 0.425). The 5-year freedom from reoperation rates for D1 and D2 groups were 80.0% and 97.1% in overall cohort (P = 0.011), and 93.6% and 97.1% in matched cohort (P = 0.474), respectively.

Conclusions

Patients with D1-AAD had a higher risk of in-hospital mortality than those with D2-AAD. However, for patients who survived to discharge, the 5-year survival rates were comparable between both groups.

A randomized trial comparing axillary versus innominate artery cannulation for aortic arch surgery

BACKGROUND

Cerebral protection remains the cornerstone of successful aortic surgery; however, there is no consensus as to the optimal strategy.

OBJECTIVE

To compare the safety and efficacy of innominate to axillary artery cannulation for delivering antegrade cerebral protection during proximal aortic arch surgery.

METHODS

This randomized controlled trial (The Aortic Surgery Cerebral Protection Evaluation CardioLink-3 Trial, ClinicalTrials.gov Identifier: NCT02554032), conducted across 6 Canadian centers between January 2015 and June 2018, allocated 111 individuals to innominate or axillary artery cannulation. The primary safety outcome was neuroprotection per the appearance of new severe ischemic lesions on the postoperative diffusion-weighted-magnetic resonance imaging. The primary efficacy outcome was the difference in total operative time. Secondary outcomes included 30-day all-cause mortality and postoperative stroke.

RESULTS

One hundred two individuals (mean age, 63 ± 11 years) were in the primary safety per-protocol analysis. Baseline characteristics between the groups were similar. New severe ischemic lesions occurred in 19 participants (38.8%) in the axillary versus 18 (34%) in the innominate group (P for noninferiority = .0009). Total operative times were comparable (median, 293 minutes; interquartile range, 222-411 minutes) for axillary versus (298 minutes; interquartile range, 231-368 minutes) for innominate (P for superiority = .47). Stroke/transient ischemic attack occurred in 4 (7.1%) participants in the axillary versus 2 (3.6%) in the innominate group (P = .43). Thirty-day mortality, seizures, delirium, and duration of mechanical ventilation were similar in both groups.

CONCLUSIONS

diffusion-weighted magnetic resonance imaging assessments indicate that antegrade cerebral protection with innominate cannulation is safe and affords similar neuroprotection to axillary cannulation during aortic surgery, although the burden of new neurological lesions is high in both groups.

Influence of moderate hypothermic circulatory arrest on outcome in patients undergoing elective replacement of thoracic aorta

Background

The ideal technique of cerebral protection in the surgical operation of the ascending aorta.is currently controversial. The current analysis evaluates the influence of moderate hypothermic circulatory arrest (MHCA) on elective replacement of the ascending aorta.

Methods

The study included 905 consecutive patients between 2001 and 2015, who underwent replacement of ascending aorta in MHCA. Patients were divided according to the postoperative 30-day mortality into survivor und non-survivor group.

Results

The average age was 66.5±11.1 in survivors vs. 70.0±10.5 years in non-survivors (P=0.057). The survivor group had a significantly lower Euro-SCORE II than non-survivors [4.0% (2.3, 6.6) vs. 9.5% (4.8, 20.9); P<0.001)]. The incidence of coronary heart disease (38.0% vs. 58.3%; P=0.022) and chronic renal failure (10.0% vs. 33.3%, P<0.001 was significantly higher in non-survivors. Intraoperatively, the cardiopulmonary bypass time [140 min (112, 185) vs. 194 min (164, 271); P<0.001] and cross-clamping time [91 min (64, 124) vs.119 min (94, 157); P<0.001] were significantly longer in non-survivors. However, the MHCA time was similar in both groups with statistical significance (P=0.023). Postoperatively, re-exploration due to bleeding was highly significant in non-survivors (5.4% vs. 33.3%; P<0.001) with a higher incidence of stroke (4.6% vs. 33.3%; P<0.001). The duration of mechanical ventilation was significantly shorter in survivors than in non-survivors [17 h (12, 26) vs. 147 h (49, 337); P<0.001] with a lower incidence of pulmonary infection (6.0% vs.16.7%; P=0.023). The multivariable logistic regression analysis showed age, female gender, aortic aneurysm, additional CABG, total arch replacement and cardiopulmonary bypass time were independent risk factors for 30-day mortality.

Conclusions

The acceptable morbidity and mortality rates show that MHCA can be considered as a safe technique for cerebral protection in surgical replacement of thoracic aorta.

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.

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.

Surgical rescues for critical hemopericardium complicated by acute type A aortic dissection: Emergent subxiphoid pericardiotomy or cardiopulmonary bypass first?

Background

Hemopericardium is a common and hazardous complication of acute type A aortic dissection (ATAAD). This retrospective study aimed to clarify the short-term and mid-term outcomes in patients who underwent surgical rescues for hemopericardium complicated by ATAAD.

Methods

Between January 2007 and March 2019, 586 consecutive patients underwent ATAAD repair at our institution. According to preoperative computed tomography, hemopericardium was found in 191 patients (32.6%), 150 were stabilized with medical treatment, and 41 underwent surgical rescues for critical hemodynamics. The 41 patients were classified into groups according to their rescue procedures: emergent subxiphoid pericardiotomy (E-SXP group, n = 26, 63.4%) or emergent cardiopulmonary bypass (E-CPB group, n = 15, 36.6%). Clinical features, surgical information, postoperative complications, and 3-year survival were analyzed and compared.

Results

Demographics, comorbidities and aortic repair procedures were generally homogenous between the two groups, except for sex. The average systolic blood pressure was 62.4 ± 13.3 mmHg and 67.1 ± 13.1 mmHg in the E-SXP and E-CPB groups, respectively. A total of 29.3% of patients underwent cardiopulmonary resuscitation (CPR) before surgical rescues. The in-hospital mortality was similar (30.8% versus 33.3%, P = 0.865) in the two groups. Multivariate analysis revealed that preoperative CPR was an in-hospital predictor of mortality. For patients who survived to discharge, 3-year cumulative survival rates were 87.8% ± 8.1% and 60.0% ± 19.7% in the E-SXP and E-CPB groups, respectively (P = 0.170).

Conclusions

Patients who underwent surgical rescues for ATAAD-complicated hemopericardium are at a high risk of in-hospital mortality. The two rescue procedures revealed similar short-term and mid-term outcomes.

Open aortic arch surgery: the gold standard method

Aortic arch pathologies are complex and treating them requires close team collaboration and technical skills to provide safe outcomes with low morbidity and mortality rates. Such challenges are facing both aortic and vascular surgeons. Open aortic arch repair has been the standard method of practice in all cases of aortic arch pathologies for the last four decades since the very first successful published case series by Griepp et al. during 1975. However, since then, repair of multi-segmented thoracic aortic pathologies has been explored through endovascular techniques; this is with or without open repair as a one-stage procedure especially in high-risk and elderly patients. Although the role of endovascular techniques in thoracoabdominal aorta is well established, its utilization as solo technique in aortic arch pathologies remains debatable. In this review, we highlight current evidences behind using open, endovascular, and hybrid procedures in aortic arch surgery.

Simplified surgical approach to improve surgical outcomes in the center with a small volume of acute type A aortic dissection surgery

BACKGROUND:

Despite recent advances in surgical techniques and perioperative management, the surgical mortality of acute type A aortic dissection remains high.

OBJECTIVE:

In a hospital with few acute type A aortic dissection operations, we retrospectively investigated whether simplified surgical approach could obtain proper surgical outcomes.

METHODS:

Between October 2007 and December 2016, we performed emergency surgery in 99 patients who had acute type A aortic dissection, including replacement of the hemi-arch in 62 patients (63%) and total arch in 32 patients (32%) and aortic root surgery in 7 patients (7%). Surgical strategy has been simplified over time.

RESULTS:

We performed right axillary artery perfusion in 61 patients (62%) and antegrade cerebral perfusion in 78 patients (79%). During the last 3 years, in-hospital mortality was decreased to 4% (2/47). Preoperative unresolved shock was an independent predictor of hospital death. Although the patients with total arch replacement or aortic root surgery had a mean significantly long cardiopulmonary bypass or circulatory arrest time, in-hospital mortality or neurologic complications was not increased.

CONCLUSIONS:

Simplified surgical approach could provide a reasonable surgical outcome in acute type A aortic dissection surgery in a center with a small volume of acute aortic dissection surgery.

Combining Cerebral Perfusion With Retrograde Inferior Vena Caval Perfusion for Aortic Arch Surgery

Hypothermic circulatory arrest and selective cerebral perfusion are standard procedures during total arch replacement to treat acute type A aortic dissection. However, organ ischemia during anastomosis between the graft and descending aorta contribute to high risk of mortality and morbidity. Here we describe the combination of antegrade cerebral perfusion and retrograde inferior vena caval perfusion as a way to ensure continual perfusion of the brain, abdominal viscera, and spinal cord during anastomosis and thereby improve outcomes of total arch replacement.

An innovative arch-first surgical procedure under moderate hypothermia for acute type A aortic dissection

BACKGROUND

We hypothesized that the arch-first procedure without extra devices under moderate-to-mild systemic hypothermia during acute type A aortic dissection is safe and efficient and will improve patient outcome compared with the standard total arch replacement technique.

METHODS

From December 2014 to February 2017, 89 patients were enrolled in this study, 52 of whom underwent conventional deep hypothermic circulatory arrest (DHCA, 24.2±0.71 °C) using the antegrade cerebral perfusion surgical procedure (Group A) and 37 of whom underwent the "arch-first" technique with moderate (27.4±1.1 °C) systemic hypothermia during antegrade cerebral perfusion (Group B). The clinical data, surgical and postoperative data, complications, and mortality of the two groups were analyzed.

RESULTS

The cardiopulmonary bypass (171.3±40.0 min) and awakening time (7.0 hours) was significantly decreased in Group B. Two patients died 30 d after surgery (5.4%, two of 37) in Group B. The incidence of transient neurologic deficit (2.7%) and distal organ complications (5.4%) was lower in Group B.

CONCLUSIONS

In patients with acute type A aortic dissection involving the arch, the innovative arch-first surgical procedure could provide feasible and safe treatment outcomes, which brings us closer to the goal of performing surgery with moderate-to-mild systemic hypothermia with better cerebral, distal organ, and survival outcomes.

Brain protection in aortic arch aneurysm: antegrade or retrograde?

During open aortic arch repair, there is an interruption of cerebral perfusion and to prevent neurological sequelae, the hypothermic circulatory arrest has been established to provide sufficient brain protection coupled with adjuncts including retrograde and antegrade cerebral perfusion. To date, brain protection during open aortic arch repair is a contested topic as to which provides superior brain protection with little evidence existing to suggest supremacy of one modality over the other. This article reviews current literature reflecting on key and emerging studies in brain protection and their associated outcomes in patients undergoing open aortic arch surgery.

The Risk of Neurological Dysfunctions after Deep Hypothermic Circulatory Arrest with Retrograde Cerebral Perfusion

OBJECTIVE

Retrograde cerebral perfusion (RCP) is a brain protection technique that is adopted generally for anticipated short periods of deep hypothermic circulatory arrest (DHCA). However, the real impact of this technique on cerebral protection during DHCA remains a controversial issue.

METHODS

For 344 (59.5%) of 578 consecutive patients (mean age, 66.9 ± 10.9 years) who underwent cardiovascular surgery under DHCA at the present authors' institution (1999-2015), RCP was the sole technique of cerebral protection that was adopted in addition to deep hypothermia. Surgery of the thoracic aorta was performed in 95.9% of these RCP patients; in 92 cases there was an aortic arch involvement. Outcomes were reviewed retrospectively. The focus was on postoperative neurological dysfunctions.

RESULTS

There were 33 (9.6%) in-hospital deaths. Thirty-one (9%) patients had permanent neurological dysfunctions and 66 (19.1%) transitory neurological dysfunctions alone. Age older than 74 years (odds ratio [OR], 1.88, P = .023), surgery for acute aortic dissection (OR, 2.57; P = .0009), and DHCA time longer than 25 minutes (OR, 2.44; P = .0021) were predictors of neurological dysfunctions. The 10-year nonparametric estimate of freedom from all-cause death was 61.8% (95% confidence interval, 57.8%-65.8%). Permanent postoperative neurological dysfunctions were risk factors for cardiac or cerebrovascular death (hazard ratio, 2.6; P = .039) even after an adjusted survival analysis (P < .04).

CONCLUSIONS

According to the study findings, RCP, in addition to deep hypothermia, combines with a low risk of neurological dysfunctions provided that DHCA length is 25 minutes or less. Permanent postoperative neurological dysfunctions are predictors of poor late survival.

Axillary versus innominate artery cannulation for antegrade cerebral perfusion in aortic surgery: design of the Aortic Surgery Cerebral Protection Evaluation (ACE) CardioLink-3 randomised trial

INTRODUCTION

Neurological injury remains the major cause of morbidity and mortality following open aortic arch repair. Systemic hypothermia along with antegrade cerebral perfusion (ACP) is the accepted cerebral protection approach, with axillary artery cannulation being the most common technique used to establish ACP. More recently, innominate artery cannulation has been shown to be a safe and efficacious method for establishing ACP. Inasmuch as there is a lack of high-quality data comparing axillary and innominate artery ACP, we have designed a randomised, multi-centre clinical trial to compare both cerebral perfusion strategies with regards to brain morphological injury using diffusion-weighted MRI (DW-MRI).

METHODS AND ANALYSIS

110 patients undergoing elective aortic surgery with repair of the proximal arch requiring an open distal anastamosis will be randomised to either the innominate artery or the axillary artery cannulation strategy for establishing unilateral ACP during systemic circulatory arrest with moderate levels of hypothermia. The primary safety endpoint of this trial is the proportion of patients with new radiologically significant ischaemic lesions found on postoperative DW-MRI compared with preoperative DW-MRI. The primary efficacy endpoint of this trial is the difference in total operative time between the innominate artery and the axillary artery cannulation group.

ETHICS AND DISSEMINATION

The study protocol and consent forms have been approved by the participating local research ethics boards. Publication of the study results is anticipated in 2018 or 2019. If this study shows that the innominate artery cannulation technique is non-inferior to the axillary artery cannulation technique with regards to brain morphological injury, it will establish the innominate artery cannulation technique as a safe and potentially more efficient method of antegrade cerebral perfusion in aortic surgery.

TRIAL REGISTRATION NUMBER

NCT02554032.

Regional Practice Patterns and Outcomes of Surgery for Acute Type A Aortic Dissection

BACKGROUND

The surgical management of acute type A aortic dissection is evolving, and many aortic centers of excellence are reporting superior outcomes. We hypothesize that similar trends exist in a multiinstitutional regional consortium.

METHODS

Records for 884 consecutive patients who underwent aortic operations (2003 to 2015) for acute type A aortic dissection were extracted from a regional The Society of Thoracic Surgeons database. Patients were stratified into three equal operative eras. Differences in outcomes and risk factors for morbidity and mortality were determined.

RESULTS

Surgical procedures for type A aortic dissection are increasing in extent and complexity. Aortic root repair was performed in 16% of early era cases compared with 67% currently (p < 0.0001). Similarly, aortic arch repair increased from 27% to 37% cases (p < 0.0001). Cerebral perfusion is currently used in 85% of circulatory arrest cases, most frequently antegrade (57%). Total circulatory arrest times increased (29 minutes vs 31 minutes vs 36 minutes; p = 0.005), but times without cerebral perfusion were stable (12 minutes vs 6 minutes; p = 0.68). Although the operative mortality rate remained stable at 18.9% during the 3 operative eras, there were significant decreases in pneumonia and reoperations (p < 0.05). Predictors of operative mortality and major morbidity are age (odds ratio [OR], 1.04; p < 0.0001), previous stroke (OR, 2.09; p = 0.03), and elevated creatinine (OR, 1.31; p = 0.01). Importantly, the extent of aortic operation did not increase risk for morbidity or mortality.

CONCLUSIONS

Operative morbidity and mortality remain significant for type A aortic dissection, but lower than historical outcomes. The extent of aortic surgery has increased, resulting in adaptive cerebral protection changes in contemporary "real-world" practice.

Intraoperative care for aortic surgery using circulatory arrest

The total circulatory arrest (CA) is necessary to achieve optimal surgical conditions in certain aortic pathologies, especially in those affecting the ascending aorta and aortic arch. During this procedure it is necessary to protect all the organs of ischemia, especially those of the central nervous system and for this purpose several strategies have been developed. The first and most important protective method is systemic hypothermia. The degree of hypothermia and the route of application have been evolving and currently tend to use moderate hypothermia (MH) (20.1-28 °C) associated with unilateral or bilateral selective cerebral perfusion methods. In this way the neurological results are better, the interval of security is greater and the times of extracorporeal circulation are smaller. Even so, it is necessary to take into account that there is the possibility of ischemia in the lower part of the body, especially of the abdominal viscera and the spinal cord, therefore the time of circulatory stop should be limited and not to exceed 80 minutes. Evidence of possible neurological drug protection is very weak and only mannitol, magnesium, and statins can produce some benefit. Inhalational anesthetics and some intravenous seem to have advantages, but more studies would be needed to test their long-term benefit. Other important parameters to be monitored during these procedures are blood glucose, anemia and coagulation disorders and acid-base balance. The recommended monitoring is common in complex cardiovascular procedures and it is of special importance the neurological monitoring that can be performed with several techniques, although currently the most used are Bispectral Index (BIS) and Near-Infrared Spectroscopy (NIRS). It is also essential to monitor the temperature routinely at the nasopharyngeal and bladder level and it is important to control coagulation with rotational thromboelastometry (ROTEM).

A Clinical Protocol for Goal Directed Cerebral Perfusion during Aortic Arch Surgery

OBJECTIVE

The optimal strategy to deliver antegrade cerebral perfusion for cerebral protection during hypothermic circulatory arrest has not been established. The purpose of this review was to present our current clinical protocol utilizing selective antegrade cerebral perfusion during aortic arch surgery and to compare it to other published experience.

CLINICAL PROTOCOL

Since 2013, our clinical protocol for aortic arch surgery has evolved to using selective antegrade cerebral perfusion via the innominate artery, moderate hypothermia, and ancillary strategies such as goal-directed perfusion (GDP). Other published techniques favored antegrade cerebral perfusion but were limited by smaller cannulae, multiple cannulation sites, and lower cooling temperatures.

CONCLUSION

Our clinical protocol may offer higher flow rates, avoid complications associated with additional cannulae, and provide an easy setup for dual arterial perfusion. Additionally, GDP has enhanced our understanding of metabolic physiology and may facilitate the development of a better cerebral protection strategy.