Antegrade versus retrograde cerebral perfusion for hemiarch replacement with deep hypothermic circulatory arrest: does it matter? A propensity-matched analysis

A stented elephant trunk procedure with retrograde cerebral perfusion for a rare type of pseudoaneurysm with an aberrant right subclavian artery

BACKGROUND

Aberrant right subclavian artery (ARSA) is a rare congenital vascular anomaly that increases the risk of aortic dissection (AD). Although several treatment options for cases of AD with ARSA have been proposed, such as traditional surgery, thoracic endovascular aortic repair, and a hybrid procedure, a consensus regarding the optimal treatment strategy has not yet been established. And there are no reported cases of pseudoaneurysm combined with ARSA.

CASE PRESENTATION

A 44-year-old male was admitted with a 7-days history of chest pain. A physical examination was almost normal. Computed tomography angiography (CTA) showed an ARSA arose from the distal aortic arch and pseudoaneurysm located distal to the origin of the ARSA. The stented elephant trunk (SET) procedure with retrograde cerebral perfusion (RCP) was performed under moderate hypothermic circulatory arrest. The postoperative CTA demonstrated a well-perfused ARSA, left subclavian artery (LSA), left common carotid artery (LCCA), and right common carotid artery (RCCA), and occluded pseudoaneurysm with no endoleaks. He was discharged on postoperative day 9 and was doing well during his 6-months follow-up.

CONCLUSIONS

With a smaller incision, a simple cannulation method, shorter surgical and circulatory arrest times, fewer blood transfusion requirements, and effective brain protection, the SET procedure with RCP can be a safe and feasible treatment option for complicated aortic arch anomalies with ARSA.

Reoperative total arch replacement after previous cardiovascular surgery: Outcomes in 426 consecutive patients

OBJECTIVE

Total aortic arch replacement (TAR) after previous cardiovascular surgery is technically challenging and is becoming more frequent as outcomes for primary arch repair have improved. primary. We analyzed outcomes of reoperative compared with first-time TAR.

METHODS

The institutional aortic database was queried to identify consecutive patients undergoing TAR between 1997 and 2022. In total, 426 patients underwent TAR, of whom 150 (35%) had previous cardiovascular surgery (reop TAR) and 276 (65%) underwent their first cardiovascular operation.

RESULTS

The reop TAR group was younger (61 ± 13 vs 71 ± 11, P < .001) with more comorbidities such as ischemic heart disease (12% vs 4.3%, P = .006), previous stroke (36% vs 14.5%, P < .001), and renal impairment (24% vs 12.7%, P = .004). Reop TAR had longer cardiac ischemic times (119.3 ± 45.5 minutes vs 98 ± 31.9 minutes, P < .001), a greater operative mortality (3.3% vs 0.4%, P = .040), and incurred a 4-fold increased risk of major adverse event (95% confidence interval [CI], 1.41-11.49, P = .009). Ten-year survival was also lower in the reop TAR cohort (76% vs 82.2%; hazard ratio, 1.79; 95% CI, 1.12-2.86, P = .015) and there was greater need for late reinterventions, mainly on the downstream aorta (hazard ratio, 1.29; 95% CI, 1.03-1.62, P = .024).

CONCLUSIONS

Reop TAR is a technically challenging operation and is associated with increased operative mortality and adverse events. Gratifying results can be obtained with meticulous surgical planning and focused attention on end-organ protection. Late reinterventions occur in a significantly greater percentage of patients undergoing reop TAR, and future studies should focus attention on identifying those at-risk groups who may benefit from a more aggressive index procedure.

Cannula Placement for Cerebral Protection Without Circulatory Arrest in Patients Undergoing Hemiarch Aortic Aneurysm Repair

BACKGROUND

Aortic aneurysms involving the proximal aortic arch, which require hemiarch-type repair, typically require circulatory arrest with antegrade cerebral perfusion. Left carotid antegrade cerebral perfusion (LCP) via distal arch cannulation without circulatory arrest was used in this study's patient population. The goal was to assess the operative efficiency and clinical outcomes of using a distal arch cannulation technique that would not require any hypothermic circulatory arrest (HCA) time compared with more traditional brachiocephalic artery cannulation with right-sided unilateral antegrade cerebral perfusion (RCP) and HCA.

METHODS

A single-center retrospective review of patients with replacement of the distal ascending aorta involving the proximal arch was performed. Patients with an intramural hematoma or dissection were excluded. Between January 2015 and December 2019, 68 adult patients had undergone a hemiarch repair because of aneurysmal disease. Analysis of baseline demographics, operative data, and clinical outcomes was performed.

RESULTS

Comparing the 68 patients: 21 patients were treated with RCP (via brachiocephalic artery graft with HCA), and 47 patients were treated with LCP (via distal aortic arch cannulation with cross-clamp between the brachiocephalic and left common carotid arteries without HCA). Baseline characteristics and outcomes were evaluated for both groups. The LCP group was younger (LCP median [IQR] age, 60 [53-65] years vs RCP median [IQR] age, 67 [59-71] years]. Sex, race, body mass index, comorbidities, and ejection fraction were similar between the groups. Cardiopulmonary bypass time (LCP, 123 minutes vs RCP, 149 minutes) and unilateral cerebral perfusion time (LCP, 17 minutes vs RCP, 22 minutes) were longer in the RCP group. Bleeding, prolonged ventilatory support, kidney failure, and length of stay were similar. In-hospital mortality was 2% in the LCP group vs 0% in the RCP group. Stroke occurred in 2 patients (4.2%) in the LCP group and in 0% of the RCP group. Mortality at 6 months in the LCP and RCP groups was 3% and 10%, respectively.

CONCLUSION

Distal arch cannulation with LCP without HCA is a reasonable and safe alternative strategy for patients requiring hemiarch replacement for aneurysmal disease. This technique may provide additional benefits by avoiding circulatory arrest in these complex cases.

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.

Challenging Paradigm Limits of Retrograde Cerebral Perfusion During Lower Body Circulatory Arrest

INTRODUCTION

Retrograde cerebral perfusion (RCP) is a safe and effective technique to augment cerebral protection during lower body circulatory arrest in patients undergoing elective hemiarch replacement. However, recommendations guiding optimal temperature, flow rate, and perfusion pressure are outdated and potentially overly limiting. We report our experience using RCP for elective hemiarch replacement with parameters that challenge the currently accepted paradigm.

METHODS

This was a single-center, retrospective analysis of 319 adult patients who underwent elective hemiarch replacement between February 2010 and 2021 using hypothermic lower body circulatory arrest with RCP alone, RCP followed by antegrade cerebral perfusion (ACP), or ACP alone. Flow rates were adjusted to maintain cerebral perfusion pressure between 30 and 50 mm Hg for RCP and between 40 and 60 mm Hg for ACP.

RESULTS

RCP was used in 22.6% (n = 72) of cases, whereas ACP alone was performed in 77.4% (n = 247) of cases. Baseline patient characteristics were similar between groups. Patients undergoing RCP demonstrated shorter cross-clamp time (97.0 min versus 100.0 min, P = 0.034) and shorter lower body circulatory arrest time (7.0 min versus 10.0 min, P < 0.0001) compared with ACP alone. Nadir bladder temperature was equivalent between groups (27.3°C versus 27.5°C, P = 0.752). There were no significant differences in postoperative complications, neurologic outcomes, or mortality.

CONCLUSIONS

Moderate hypothermic lower body circulatory arrest combined with RCP at target perfusion pressures of 30-50 mm Hg in patients undergoing elective hemiarch replacement results in equivalent neurologic outcomes and overall morbidity to cases using ACP alone. These results challenge the currently accepted paradigm for RCP, which typically uses deep hypothermia while keeping perfusion pressures below 25 mm Hg.

Contemporary utilization of the axillary artery in cardiac surgery

INTRODUCTION

The axillary artery is a reliable inflow vessel when addressing pathology of the aortic root and aortic arch that may preclude standard central cannulation strategies. This narrative review examines the use of the axillary artery in cardiac surgery. Anatomy, indications for use, cannulation strategies, and potential complications will be discussed.

METHODS

A comprehensive review of the current literature was performed using PubMed, Cochrane Review, and authoritative committee guidelines. A narrative review incorporating current available evidence was undertaken.

COMMENT

Use of the axillary artery in select cardiac surgical cases is reliable, reproducible, and may be preferable in certain cases involving ascending aortic pathology, reoperative surgery, porcelain aorta, access for transcatheter valve therapies, and peripheral mechanical circulatory support.

Post-Operative Kidney Function Using Deep Hypothermic Circulatory Arrest (DHCA) in Aortic Arch Operation

Background

Although deep hypothermic circulatory arrest (DHCA) is a useful option to protect the central nervous system during aortic arch operations, the influence of simultaneous renal ischemia remains controversial.

Patients and Methods

This is a retrospective observational study. Sixty-three patients who underwent thoracic aortic surgery with DHCA and 24 patients who underwent cardiac surgery without DHCA were included in this study. The mean age, preoperative serum creatinine (Cr) level, preoperative estimated glomerular filtration rate (eGFR), peak serum Cr level up to 48 hrs post-operative, elevation rate of Cr compared to the preoperative serum Cr, urine volume rate up to 48 hrs post-operative and AKI staging using the KDIGO criteria were estimated for each patient. Clinical parameters for 3 months after the operation and the 3-month post-operative mortality rate were assessed. Mean values indicating kidney function or distribution of the AKI stages were compared between patients with and without DHCA. Patients with DHCA were further divided according to the duration of ischemia to compare the values for the kidney function of each group, distribution of AKI stages and mortality.

Results

The parameters indicating AKI of the patients with DHCA were significantly more severe than those without DHCA. Patients who had undergone an ischemic state for more than 40 min revealed significantly higher peak serum Cr, elevation rate of serum Cr, less urine volume up to 48 hrs post-operative compared with those without DHCA. Distribution of the AKI stages was related to the duration of ischemia. The 3-month post-operative mortality of the patients with DHCA was significantly higher than those without DHCA.

Limitations

This study had limitations such as its retrospective design and small number patients, and the data will be required confirmation with other prospective studies.

Conclusion

DHCA is closely related to AKI up to 48 hrs post-operative and death during the 3 months following surgery.

Cerebral protection using deep hypothermic circulatory arrest versus retrograde cerebral perfusion for aortic hemiarch reconstruction

BACKGROUND

With evolutions in technique, recent data encourage the use of cerebral perfusion during aortic arch repair. However, a randomized data have demonstrated higher rates of neurologic injury according to MRI lesions using antegrade cerebral perfusion during hemiarch reconstruction.

METHODS

This was a retrospective review of two institutional aortic center databases to identify adult patients who underwent aortic hemiarch reconstruction for elective aortic aneurysm or acute type A aortic dissection. Patients were stratified according to cerebral protection method: (1) deep hypothermic circulatory arrest (DHCA) group versus (2) DHCA/retrograde cerebral perfusion (RCP) group.

RESULTS

A total of 320 patients and 245 patients underwent hemiarch reconstruction for aortic aneurysm electively and aortic dissection, respectively. In aneurysmal pathology, the DHCA group included 133 patients and the DHCA/RCP group included 187 patients. Operative mortality was 0.8% in the DHCA group and 2.7% in the DHCA/RCP group (p = 0.41). Kaplan-Meier survival estimates revealed comparable 2-year survival (p = 0.14). In dissection, 43 patients and 202 patients were included in the DHCA group and the DHCA/RCP group, respectively. Operative mortality was equivalent between the two groups (11.6% in the DHCA group and 9.4% in the DHCA/RCP group, p = 0.58). Long-term survival was similar at 2 years between the groups (p = 0.06). Multivariable analysis showed cerebral perfusion strategy was not associated with the composite outcome of operative mortality and stroke.

CONCLUSIONS

In treating both elective and acute ascending aortic pathologies with hemiarch reconstruction, both DHCA alone or in combination with RCP yield comparable results.

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.

Perfusion of brain and viscera using modified retrograde cerebral perfusion for aortic arch surgery

Anterograde or retrograde cerebral perfusion can protect the brain from ischemic injury during hypothermic circulatory arrest (HCA), but neither type of perfusion provides blood flow to the abdominal viscera. Here, we report a modified retrograde cerebral perfusion (RCP) technique in which we tethered both superior and inferior venae cavae with bands around the cannula and clamped the distal ends of the drainage tubes of both venae cavae. Modified RCP may provide greater blood flow to the brain and lower body than conventional RCP during HCA in hemiarch surgery.

Safety of retrograde cerebral perfusion under moderate hypothermia for hemiarch replacement

OBJECTIVES

Aortic surgeries performed under moderate hypothermia require antegrade cerebral perfusion. The influence of retrograde cerebral perfusion under moderate hypothermic circulatory arrest remains unknown. To clarify this effect, this study aimed to compare the early outcomes of retrograde versus antegrade cerebral perfusion under moderate hypothermia for hemiarch replacement.

METHODS

Between March 2009 and April 2020, 391 hemiarch replacements under moderate hypothermic circulatory arrest via median sternotomy were performed at our institution. Of these, 70 involved retrograde perfusion and 162 involved antegrade perfusion. Propensity score matching was used to compare 61 pairs of retrograde and antegrade cases.

RESULTS

Retrograde and antegrade strategy under moderate hypothermia resulted in comparable operative mortality (3.3% vs. 1.6%, P > 0.99), permanent neurological deficits (8.5% vs. 6.6%, P > 0.99), and temporary neurological deficits (24.6% vs. 39.3%, P = 0.33). Retrograde surgery was associated with shorter circulatory arrest times (31.4 ± 8.2 min vs. 37.4 ± 12.2 min, P = 0.005) and fewer red blood cell transfusions (4.6 ± 3.9 units vs. 8.2 ± 5.1 units, P < 0.001) than those with antegrade surgery.

CONCLUSIONS

Retrograde cerebral perfusion under moderate hypothermia for hemiarch replacement yields excellent operative outcomes, equivalent to those achieved using an antegrade strategy.

Matched comparison of 3 cerebral perfusion strategies in open zone-0 anastomosis for acute type A aortic dissection

OBJECTIVES

The present study aims to investigate outcomes after the surgical treatment of acute type A aortic dissection in regard to three available selective cerebral perfusion strategies.

METHODS

From 2000 to 2019, patients were selected based on the employment of either retrograde cerebral perfusion (RCP), unilateral antegrade cerebral perfusion (uACP) or bilateral antegrade cerebral perfusion (bACP) during open zone-0 anastomosis. Propensity score TriMatch analysis considering several preoperative and intraoperative variables was used to identify well-balanced triplets. The primary end point of the study was a new cerebral operation-related neurologic deficit.

RESULTS

Operative times (operation time, cardiopulmonary bypass time, reperfusion time) were significantly longer in the RCP group, in which deeper hypothermia was applied (27.5 [24-28], 28 [26-28] and 16 [16-17]°C for uACP, bACP and RCP, respectively, P-value <0.001). The RCP group showed higher red blood cell concentrates and fresh frozen plasma transfusion rates. No significant difference of new cerebral operation-related neurologic deficit was observed between the 3 groups (12.9% vs 12.9% vs 11.3% for RCP, uACP and bACP, P-value = 0.86). In addition, 30-day mortality showed similar distribution independently of the cerebral perfusion strategy adopted (17.7% vs 14.5% vs 17.7% for RCP, uACP and bACP, P-value = 0.86).

CONCLUSIONS

However, based on a small sample size, the comparison showed no relevant differences in terms of neurologic outcome and 30-day mortality, confirming RCP, uACP and bACP as safe and reproducible selective cerebral perfusion strategies in surgery for acute type A aortic dissection.

The New York experience of open arch surgery

BACKGROUND

Aortic arch repair has undergone constant evolution since its inception with improving outcomes. A sizeable number of competing techniques and strategies have been described, with no single optimal method endorsed by the surgical community. We describe our experience with open aortic arch repair in a high-volume center.

METHODS

We queried our aortic database for consecutive patients undergoing aortic arch repair from 1997-2021. Those undergoing hemiarch repair were compared to those undergoing total arch repair. Outcomes were compared using multivariate analysis.

RESULTS

Of 1308 patients undergoing aortic arch repair, 953 underwent hemiarch repair and 355 underwent total arch repair. The median age was 69 [interquartile ratio 58-76] and 61.7% were men. Hemiarch patients more frequently hade aortic dissection (28.5 vs 11.8%, P < 0.001) and urgent or emergent procedure status (45.1 vs 30.4%, P < 0.001). Overall operative mortality was 2.7% and significantly higher in the hemiarch group (3.5 vs 0.6%, P=0.007). No difference in the incidence of major adverse events (MAE) including myocardial infarction, cerebrovascular accident, new need for dialysis, re- exploration for bleeding, and tracheostomy was found between the two groups. Multivariate analysis found diabetes, urgent or emergent procedure status, preoperative renal dysfunction, New York Heart Association class III/IV symptoms, and connective tissue disease to be independent predictors of MAE.

CONCLUSIONS

Retrograde cerebral perfusion with deep hypothermic circulatory arrest is safe and effective, with no appreciable difference in neurologic outcomes when comparing hemiarch to total arch strategies. Rates of mortality and MAE compare favorably with strategies utilizing antegrade cerebral perfusion.

Proximal versus extensive repair in acute type A aortic dissection: an updated systematic review and meta-analysis

OBJECTIVES

Our aim was to compare the safety and efficacy of proximal repair (PR) versus extensive repair (ER) for acute type A aortic dissection (ATAAD).

METHODS

A literature search in three databases was performed according to the PRISMA statement. Studies comparing PR versus ER for ATAAD were included. Random-effects meta-analyses were performed.

RESULTS

A total of 27 studies incorporating 7113 patients (PR: 5080; ER: 2033) were included. Patients undergoing PR presented decreased in-hospital mortality (odds ratio [OR]: 0.67 [95% Confidence Interval (95% CI) 0.53-0.85]; p < 0.01) and post-operative bleeding (OR 0.75 [95% CI 0.60-0.95]; p = 0.02) compared to ER. Meta-regression analysis revealed that in-hospital mortality was not influenced by differences regarding the extent of dissection (p = 0.43). Cardiopulmonary bypass time (SMD:-0.93 [95% CI - 1.22, - 0.66]; p < 0.01) and length of hospital stay (SMD:-0.19 [95% CI - 0.34, - 0.05]; p = 0.01) were also lower in the PR group, while there was no difference in terms of renal failure and permanent neurological deficit. The ER approach demonstrated a lower post-discharge mortality compared to PR (OR 1.46 [95% CI 1.09, 1.97]; p = 0.01), while the post-discharge reoperation rate was comparable between the two groups. 1 and 3-year overall survival (OS) were comparable between PR and ER (OR 1.05, [95% CI 0.77-1.44]; p = 0.76) and (OR 1.27 [95% CI 0.86-1.86]; p = 0.23), respectively. The 5-year OS (OR 1.67 [95% CI 1.16-2.41]; p = 0.01) was in favor of the PR arm.

CONCLUSIONS

In patients with ATAAD, PR was associated with lower odds of in-hospital mortality but higher odds of late mortality. ER and PR demonstrated similar post-operative complication and reoperation rates.

Monitoring cardiac and ascending aortic procedures

Although cardiac and aortic operations have been successfully performed for more than 60 years, the risk of neurologic complications remains high. In particular, the rate of stroke with cardiac operations continues to be significant in the 1%-5% range. Similarly, the risk of stroke with aortic operations remains in the range of 7%-10% despite many years of improving techniques. Because of this persistently high risk, the use of intra-operative neurophysiologic monitoring (IONM) has the potential of improving outcomes. This chapter provides an overview of cardiac/aortic arch procedures from the neurophysiologic standpoint and discusses the roles of different monitoring modalities in detecting injury.

Modified Technique for Retrograde Cerebral Perfusion during Hemiarch Aortic Replacement

Background  Uncertainty remains regarding the optimal method of brain protection for procedures that require repair or replacement of the aortic arch. We examined the early outcomes of a technique for brain protection in patients undergoing partial aortic arch (hemiarch) replacement that involves deep hypothermic circulatory arrest (DHCA) and retrograde cerebral perfusion (RCP) of cold blood from the superior vena cava toward the end of the arrest interval.

Methods  During a recent 15-year interval, 520 patients underwent elective or urgent/emergent ascending aortic and hemiarch replacement as an isolated (47 patients) or combined (473 patients) procedure employing DHCA (mean nasopharyngeal temperature at circulatory arrest, 17.1°C and mean duration, 19.3 minutes) supplemented with RCP of cold blood from the superior vena cava toward the end of the arrest interval (mean, 6.7 minutes). The mean age of the patients was 59.5 years, and 65% were male.

Results  The in-hospital and 30-day mortality rates were 1.2% (six patients). Seven patients (1.4%) sustained a stroke and 19 patients (3.7%) had transient neurologic dysfunction that completely resolved by the time of hospital discharge. Four patients (0.77%) developed postoperative renal failure requiring dialysis. Twenty-one patients (4%) required ventilator support for >48 hours and five patients (0.96%) required a tracheostomy. The median hospital length of stay was 6 days.

Conclusion  DHCA with a brief interval of RCP is a safe and effective technique for brain protection during hemiarch aortic replacement. RCP reduces the duration of brain ischemia and permits removal of particulate matter and air from the arterial circulation.

Does deeper hypothermia reduce the risk of acute kidney injury after circulatory arrest for aortic arch surgery?

OBJECTIVES

The impact of hypothermic circulatory arrest (HCA) temperature on postoperative acute kidney injury (AKI) has not been evaluated. This study examined the association between circulatory arrest temperatures and AKI in patients undergoing proximal aortic surgery with HCA.

METHODS

A total of 759 consecutive patients who underwent proximal aortic surgery (ascending ± valve ± root) including arch replacement requiring HCA between July 2005 and December 2016 were identified from a prospectively maintained institutional aortic surgery database. The primary outcome was AKI as defined by Risk, Injury, Failure, Loss, End Stage Renal Disease (ESRD) criteria. The association between minimum nasopharyngeal (NP) and bladder temperatures during HCA and postoperative AKI was assessed, adjusting for patient-level factors using multivariable logistic regression.

RESULTS

A total of 85% (n = 645) of patients underwent deep hypothermia (14.1-20.0°C), 11% (n = 83) low-moderate hypothermia (20.1-24.0°C) and 4% (n = 31) high-moderate hypothermia (24.1-28.0°C) as classified by NP temperature. When analysed by bladder temperature, 59% (n = 447) underwent deep hypothermia, 22% (n = 170) low-moderate, 16% (n = 118) high-moderate and 3% mild (n = 24) (28.1-34.0°C) hypothermia. The median systemic circulatory arrest time was 17 min. The incidence of AKI did not differ between hypothermia groups, whether analysed using minimum NP or bladder temperature. In the multivariable analysis, the association between degree of hypothermia and AKI remained non-significant whether analysed as a categorical variable (hypothermia group) or as a continuous variable (minimum NP or bladder temperature) (all P > 0.05).

CONCLUSIONS

In patients undergoing proximal aortic surgery including arch replacement requiring HCA, degree of systemic hypothermia was not associated with the risk of AKI. These data suggest that moderate hypothermia does not confer increased risk of AKI for patients requiring circulatory arrest, although additional prospective data are needed.

Long-term outcomes of hemiarch replacement with hypothermic circulatory arrest and retrograde cerebral perfusion

OBJECTIVE

This study sought to report outcomes of hemiarch replacement with hypothermic circulatory arrest and retrograde cerebral perfusion, and secondarily, to report outcomes of this operative approach by type of underlying aortic disease.

METHODS

This was an observational study of aortic surgeries from 2010 to 2018. All patients who underwent hemiarch replacement with retrograde cerebral perfusion were included, whereas patients undergoing partial or total arch replacement or concomitant elephant trunk procedures were excluded. Patients were dichotomized into 2 groups by underlying aortic disease; that is, acute aortic dissection (AAD) or aneurysmal degeneration of the aorta. These groups were analyzed for differences in short-term postoperative outcomes, including stroke and operative mortality (Society of Thoracic Surgeons definition). Multivariable Cox analysis was performed to identify variables associated with long-term survival after hemiarch replacement.

RESULTS

A total of 500 patients undergoing hemiarch replacement with hypothermic circulatory arrest plus retrograde cerebral perfusion were identified, of whom 53.0% had aneurysmal disease and 47.0% had AAD. For the entire cohort, operative mortality was 6.4%, whereas stroke occurred in 4.6% of patients. Comparing AAD with aneurysm, operative mortality and stroke rates were similar across each group. Five-year survival was 84.4% ± 0.02% for the entire hemiarch cohort, whereas 5-year survival was 88.0% ± 0.02% for the aneurysm subgroup and was 80.5% ± 0.03% for the AAD subgroup. On multivariable analysis, AAD was not associated with an increased hazard of death, compared with aneurysm (P = .790).

CONCLUSIONS

Morbidity and mortality after hemiarch replacement with hypothermic circulatory arrest plus retrograde cerebral perfusion are acceptably low, and this operative approach may be as advantageous for AAD as it is for aneurysm.

Aortic valve repair with a newly approved geometric annuloplasty ring in patients undergoing proximal aortic repair: early results from a single-centre experience

OBJECTIVES

Aortic insufficiency (AI) is common in patients with proximal aortic disease, but limited options exist to facilitate aortic valve repair (AVr) in this population. This study reports 'real-world' early results of AVr using newly FDA-approved trileaflet and bicuspid geometric annuloplasty rings for patients with AI undergoing proximal aortic repair (PAR) in a single referral centre.

METHODS

All patients undergoing AVr with a rigid internal geometric annuloplasty ring (n = 47) in conjunction with PAR (ascending +/- root +/- arch) were included. Thirty-six patients underwent AVr with a trileaflet ring, and 11 patients underwent AVr with a bicuspid ring. The rings were implanted in the subannular position, and concomitant leaflet repair was performed if required for cusp prolapse identified after ring placement.

RESULTS

The median age was 58 years [interquartile range (IQR) 46-70]. PAR included supracoronary ascending replacement in 26 (55%) patients and remodelling valve-sparing root replacement with selective sinus replacement in 20 (42%) patients. Arch replacement was performed in 38 (81%) patients, including hemi-arch in 34 patients and total arch in 4 patients. There was no 30-day/in-hospital mortality. Preoperative AI was 3-4+ in 37 (79%) patients. Forty-one (87%) patients had zero-trace AI on post-repair transoesophageal echocardiography, and 6 patients had 1+ AI. The median early post-repair mean gradient was 13 mmHg (IQR 5-20). Follow-up imaging was available in 32 (68%) patients at a median of 11 months (IQR 10-13) postsurgery. AI was ≤1+ in 97% of patients with 2+ AI in 1 patient. All patients were alive and free from aortic valve reintervention at last follow-up.

CONCLUSIONS

Early results with geometric rigid internal ring annuloplasty for AVr in patients undergoing PAR appear promising and allow a standardized approach to repair with annular diameter reduction and cusp plication when needed. Longer-term follow-up will be required to ensure the durability of the procedure.

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.

Review of cerebral perfusion strategies for aortic surgery with application for minimally invasive approaches

Aortic arch and hemiarch surgery necessitate the temporary interruption of blood perfusion to the brain. Despite its complexity, hemiarch and ascending aortic surgery can be performed via a minimally invasive approach. Due to the higher risk of neurological injury during a circulatory arrest, several techniques were developed to further protect the brain during this surgery. We searched the Embase, Medline, and Cochrane databases and identified articles reporting outcomes of antegrade and retrograde cerebral perfusion strategies. Herein, we outline surgical approaches, intra-operative technical considerations, and clinical outcomes of hemiarch and ascending aortic surgery. Hemiarch and ascending aortic surgery is associated with a higher risk of mortality and morbidity. Attention to the optimal approach and cerebral protection strategy has been shown to significantly affect outcomes and mitigate risk.

Factors associated with acute stroke after type A aortic dissection repair: An analysis of the Society of Thoracic Surgeons National Adult Cardiac Surgery Database

OBJECTIVES

Data from the Society of Thoracic Surgeons Adult Cardiac Surgery Database was used to examine the incidence and factors associated with acute stroke following type A repair.

METHODS

Acute type A aortic dissection repairs performed from 2014 to 2017 were identified from the Society of Thoracic Surgeons Adult Cardiac Surgery Database. The effect of cannulation strategy (eg, axillary, femoral, direct, or innominate), lowest temperature, cerebral protection techniques (antegrade cerebral profusion, retrograde cerebral perfusion, both, or none), repair technique, and institutional volume on postoperative stroke was investigated.

RESULTS

Acute type A repair was performed on 8937 patients at 772 centers, of which 7353 met inclusion criteria. Operative mortality was 17% and incidence of postoperative stroke was 13%. Axillary cannulation was associated with lower risk of stroke versus femoral (odds ratio, 0.60; P < .001). Retrograde cerebral perfusion was associated with reduced risk for stroke compared with no cerebral perfusion (odds ratio, 0.75; P = .008) or antegrade cerebral perfusion (odds ratio, 0.75; P = .007). Total arch replacement was associated with greater risk for stroke versus hemiarch technique (odds ratio, 1.30; P = .013). Longer circulatory arrest time, cerebral perfusion time, and cardiopulmonary bypass time were all related to higher risk of postoperative stroke.

CONCLUSIONS

Stroke is a common complication after type A repair. Axillary cannulation was associated with lower incidence of stroke, whereas femoral cannulation significantly increased the risk of stroke regardless of the cerebral perfusion strategy or the degree of hypothermia. Retrograde cerebral profusion was found to have reduced risk for postoperative stroke. Degree of hypothermia and center volume were not related to stroke incidence.

Neuroprotective Strategies in Repair and Replacement of the Aortic Arch

Aortic arch surgery is a technical challenge, and cerebral protection during distal anastomosis is a continued topic of controversy and discussion. The physiologic effects of hypothermic arrest and adjunctive cerebral perfusion have yet to be fully defined, and the optimal strategies are still undetermined. This review highlights the historical context, physiological rationale, and clinical efficacy of various neuroprotective strategies during arch operations.

Simple retrograde cerebral perfusion is as good as complex antegrade cerebral perfusion for hemiarch replacement

Cerebral complication is a major concern after aortic arch surgery, which may lead to death. Thus, cerebral protection strategy plays the key role to obtain respectable results in aortic arch repair. Deep hypothermic circulatory arrest was introduced in 1970s to decrease the ischemic insults to the brain. However, safe duration of circulatory arrest time was limited to 30 minutes. The 1990s was the decade of evolution for cerebral protection, in which two adjuncts for deep hypothermic circulatory arrest were introduced: retrograde and antegrade cerebral perfusion (ACP) techniques. These two cerebral perfusion techniques significantly decreased incidence of postoperative neurological dysfunction and mortality after aortic arch surgery. Although there are no large prospective studies that demonstrate which perfusion technique provide better outcomes, multiple retrospective studies implicate that ACP may decrease cerebral complications compared to retrograde cerebral perfusion (RCP) when a long circulatory arrest time is required during aortic arch reconstructions. To date, many surgeons favor ACP over RCP during a complex aortic arch repair, such as total arch replacement and hybrid arch replacement. However, the question is whether the use of ACP is necessary during a short, limited circulatory arrest time, such as hemiarch replacement? There is a paucity of data that proves the advantages of a complex ACP over a simple RCP for a short circulatory arrest time. RCP with deep hypothermic circulatory arrest is the simple, efficient cerebral protection technique with minimal interference to the surgical field-and it potentially allows to flush atheromatous debris out from the arch vessels. Thus, it is the preferred adjunct to deep hypothermic circulatory arrest during hemiarch replacement in our institution.

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.

Neurophysiological Intraoperative Monitoring During Aortic Arch Surgery

Circulatory management during replacement of the aortic arch is complex and involves a period of circulatory arrest to provide a bloodless field during arch vessel anastomosis. To guard against ischemic brain injury, tissue metabolic demand is reduced by systemically cooling the patient prior to circulatory arrest. Neurophysiological intraoperative monitoring (NIOM) is often used during the course of these procedures to provide contemporaneous assessment of brain status to help direct circulatory management decisions and detect brain ischemia. In this review, we discuss the characteristics of electrocerebral activity through the process of cooling, circulatory arrest, and rewarming as depicted through commonly used NIOM modalities, including electroencephalography and peripheral nerve somatosensory-evoked potentials. Attention is directed toward the role NIOM has traditionally played during deep hypothermic circulatory arrest, where it is used to define the point of electrocerebral inactivity or maximal cerebral metabolic suppression prior to initiating circulatory arrest while also discussing the evolving utility of NIOM when systemic circulatory arrest is initiated at more moderate degrees of hypothermia in conjunction with regional brain perfusion. The use of cerebral tissue oximetry by near-infrared spectroscopy as an alternative NIOM modality during surgery of the aortic arch is addressed as well. Finally, special considerations for NIOM and the detection of spinal cord ischemia during hybrid aortic arch repair and emerging operative techniques are also discussed.

Does moderate hypothermia really carry less bleeding risk than deep hypothermia for circulatory arrest? A propensity-matched comparison in hemiarch replacement

BACKGROUND

Moderate (MHCA) versus deep (DHCA) hypothermia for circulatory arrest in aortic arch surgery has been purported to reduce coagulopathy and bleeding complications, although there are limited data supporting this claim. This study aimed to compare bleeding-related events after aortic hemiarch replacement with MHCA versus DHCA.

METHODS

Patients who underwent hemiarch replacement at a single institution from July 2005 to August 2014 were stratified into DHCA and MHCA groups (minimum systemic temperature ≤20°C and >20°C, respectively) and compared. Then, 1:1 propensity matching was performed to adjust for baseline differences.

RESULTS

During the study period, 571 patients underwent hemiarch replacement: 401 (70.2%) with DHCA and 170 (29.8%) with MHCA. After propensity matching, 155 patients remained in each group. There were no significant differences between matched groups with regard to the proportion transfused with red blood cells, plasma, platelet concentrates, or cryoprecipitate on the operative day, the rate of reoperation for bleeding, or postoperative hematologic laboratory values. Among patients who received plasma, the median transfusion volume was statistically greater in the DHCA group (6 vs 5 units, P = .01). MHCA also resulted in a slight reduction in median volume of blood returned via cell saver (500 vs 472 mL, P < .01) and 12-hour postoperative chest tube output (440 vs 350, P < .01). Thirty-day mortality and morbidity did not differ significantly between groups.

CONCLUSIONS

MHCA compared with DHCA during hermiarch replacement may slightly reduce perioperative blood-loss and plasma transfusion requirement, although these differences do not translate into reduced reoperation for bleeding or postoperative mortality and morbidity.

How to Perfuse: Concepts of Cerebral Protection during Arch Replacement

Arch surgery remains undoubtedly among the most technically and strategically challenging endeavors in cardiovascular surgery. Surgical interventions of thoracic aneurysms involving the aortic arch require complete circulatory arrest in deep hypothermia (DHCA) or elaborate cerebral perfusion strategies with varying degrees of hypothermia to achieve satisfactory protection of the brain from ischemic insults, that is, unilateral/bilateral antegrade cerebral perfusion (ACP) and retrograde cerebral perfusion (RCP). Despite sophisticated and increasingly individualized surgical approaches for complex aortic pathologies, there remains a lack of consensus regarding the optimal method of cerebral protection and circulatory management during the time of arch exclusion. Many recent studies argue in favor of ACP with various degrees of hypothermic arrest during arch reconstruction and its advantages have been widely demonstrated. In fact ACP with more moderate degrees of hypothermia represents a paradigm shift in the cardiac surgery community and is widely adopted as an emergent strategy; however, many centers continue to report good results using other perfusion strategies. Amidst this important discussion we review currently available surgical strategies of cerebral protection management and compare the results of recent European multicenter and single-center data.

Prolonged postoperative respiratory support after proximal thoracic aortic surgery: Is deep hypothermic circulatory arrest a risk factor?

PURPOSE

In addition to the pulmonary risks associated with cardiopulmonary bypass, thoracic aortic surgery using deep hypothermic circulatory arrest (DHCA) may subject the lungs to further injury. However, this topic has received little investigation to date.

MATERIALS AND METHODS

A prospective cohort review was performed on all patients undergoing proximal thoracic aortic surgery with (n = 478) and without (n = 135) DHCA between July 2005 and February 2013 at a single institution. The primary outcome was prolonged postoperative respiratory support (PPRS), defined as any of the following: >1 day of mechanical ventilation at either fraction of inspired oxygen >0.4 and/or positive end-expiratory pressure >5 mm Hg, >2 days of supplemental O2 requirement of at least 2.5 L/min, or discharge with new O2 requirement. Independent risk factors for PPRS were identified using multivariable logistic regression.

RESULTS

Postoperative respiratory support was required in 100 patients (20.9%) with and 30 patients (22.2%) without DHCA (P = .74). Independent predictors of PPRS after proximal aortic surgery included the following: age, diabetes, history of stroke, preoperative creatinine, American Society of Anesthesiologists class 4, redo-sternotomy, total arch replacement, and transfusion requirement. Use of DHCA was not an independent risk factor for PPRS in the entire cohort. Subanalysis of only DHCA patients revealed that longer DHCA times were independently associated with PPRS.

CONCLUSIONS

Prolonged postoperative respiratory support is common after proximal aortic surgery. The use of DHCA was not associated with this complication in the overall cohort, although longer DHCA times were predictive when only the subset of patients undergoing DHCA was analyzed. Knowledge of the risk factors for PPRS after proximal aortic surgery should improve preoperative risk stratification and postoperative management of these patients.

Evolving practice pattern changes and outcomes in the era of hybrid aortic arch repair

OBJECTIVE

The role of hybrid repair in the management of aortic arch pathology, and long-term outcomes with these techniques, remains uncertain. We report a decade of experience with hybrid arch repair (HAR) and assess institutional practice patterns with regard to the use of hybrid and open techniques.

METHODS

Hybrid and open total and distal arch procedures performed between July 2005 and January 2015 were identified from a prospectively maintained, institutional aortic surgery database. Perioperative morbidity and mortality, freedom from reintervention, and long-term survival were calculated. Hybrid and open procedural volumes over the study period were assessed to evaluate for potential practice pattern changes.

RESULTS

During the study period 148 consecutive procedures were performed for repair of transverse and distal aortic arch pathology, including 101 hybrid repairs and 47 open total or distal arch repairs. Patients in the hybrid repair group were significantly older with a greater incidence of chronic kidney disease, peripheral vascular disease, and chronic lung disease. Perioperative mortality and outcomes were not significantly different between the hybrid and open groups, aside from decreased median length of stay after hybrid repair. Need for subsequent reintervention was significantly greater after hybrid repair. Unadjusted long-term survival was superior after open repair (70% 5-year survival open vs 47% hybrid; P = .03), although aorta-specific survival was similar (98% 5-year aorta-specific survival open vs 93% hybrid; P = .59). Institutional use of HAR decreased over the final 3 years of the study, with an associated increased use of open total or distal arch repairs. This was primarily the result of decreased use of native zone 0 hybrid procedures. Concurrent with this apparent increased stringency around patient selection for HAR, perioperative morbidity and mortality was reduced, including avoidance of retrograde type A dissection.

CONCLUSIONS

HAR remains a viable option for higher-risk patients with transverse arch pathology with perioperative outcomes and long-term aorta-specific survival similar to open repair, albeit at a cost of increased reintervention. This observational single-institution study would suggest decreased use in more recent years in favor of open repair due to avoidance of native zone 0 hybrid procedures. This decline in the institutional use of native zone 0 hybrid repairs was associated with improved perioperative outcomes.