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

Long-term outcomes of total arch replacement with bilateral antegrade cerebral perfusion using the "arch first" approach

ObjectiveTo report outcomes of total arch replacement (TAR) with hypothermic circulatory arrest and bilateral antegrade cerebral perfusion (bACP) using an "arch first" approach for acute Type A aortic dissection (ATAAD). The "arch first" approach involved revascularization of the aortic arch branch vessels with uninterrupted ACP, before lower body circulatory arrest, while the patient was cooling.MethodsThis was an observational study of aortic surgeries from 2010 to 2021. All patients who underwent TAR with bACP for ATAAD were included. Short-term and long-term outcomes were reported utilizing descriptive statistics and Kaplan-Meier survival estimation.ResultsA total of 215 patients were identified who underwent TAR + bACP for ATAAD. Age was 59.0 [49.0-67.0] years and 35.3% were female. 73 patients (34.0%) underwent a concomitant aortic root replacement, 188 (87.4%) had aortic cannulation, circulatory arrest time was 37.0 [26.0-52.0] minutes, and nadir temperature was 20.8 [19.4-22.5] degrees Celsius. 35 patients (16.3%) had operative mortality (STS definition), 17 (7.9%) had a new stroke, 79 (36.7%) had prolonged mechanical ventilation (>24 h), 35 (16.3%) had acute renal failure (by RIFLE criteria), and 128 (59.5%) had blood product transfusions. One-year survival was 77.1%, while 5-years survival was 67.1%. During follow-up, there were 23 (10.7%) reinterventions involving the descending thoracic aorta - either thoracic endovascular aortic repair or open thoracoabdominal aortic replacement.ConclusionsAmong patients with ATAAD, short-term postoperative outcomes after TAR + bACP using the "arch first" approach are acceptable. Moreover, this operative strategy may furnish long-term durability, with a reasonably low reintervention rate and satisfactory overall survival.

External validation of the ARCH score in patients undergoing aortic arch reconstruction under circulatory arrest

BACKGROUND

Aortic arch surgery with hypothermic circulatory arrest (HCA) carries a higher risk of morbidity and mortality compared to routine cardiac surgical procedures. The newly developed ARCH (arch reconstruction under circulatory arrest with hypothermia) score has not been externally validated. We sought to externally validate this score in our local population.

METHODS

All consecutive open aortic arch surgeries with HCA performed between 2014 and 2023 were included. Univariable and multivariable analyses were performed. Model discrimination was assessed by the C-statistic with 95% confidence intervals as part of the receiver operating characteristic (ROC) curve analysis. Model performance was visualized by a calibration plot and quantified by the Brier score.

RESULTS

A total of 760 patients (38.3% females) were included. The mean age was 61 (±13.6) years, with 56.4% of patients' age >60 years. The procedures were carried out mostly emergently or urgently (59.6%). Total arch replacement was performed in 32.5% of the patients, and aortic root procedures were carried out in 74.6%. In-hospital death occurred in 64 patients (8.4%), and stroke occurred in 5.4%. The C-statistic revealed a low discriminatory ability for predicting in-hospital mortality (area under the ROC curve, 0.62; 95% confidence interval, 0.54-0.69; P = .002); however, model calibration was found to be excellent (Brier score of 0.07).

CONCLUSIONS

The ARCH score for in-hospital mortality showed low discriminatory ability in our local population, although with excellent ability for prediction of mortality.

Preoperative Hematocrit Is Not Associated With Stroke After Surgery for Acute Type A Aortic Dissection

OBJECTIVE

To determine the impact of hematocrit on adverse neurologic events after acute type A aortic dissection (ATAAD) repair under deep hypothermic circulatory arrest.

DESIGN

Retrospective study of consecutive aortic surgeries from 2010 to 2021.

SETTING

Single institution.

PARTICIPANTS

Patients undergoing open ATAAD repairs, excluding those with preoperative cerebral malperfusion syndrome (defined as neurologic deficit with radiographic evidence of cerebral branch vessel malperfusion).

INTERVENTIONS

Patients were split into three groups: normal, low, and high hematocrit.

MEASUREMENTS & MAIN RESULTS

A total of 527 patients were included, of which 355 (67.3%) had normal hematocrit, 143 (27.1%) had low hematocrit, and 29 (5.5%) had high hematocrit. Overall, 20 (3.8%) patients had a postoperative stroke, which was comparable across groups (p = 0.59). Patients with normal hematocrit had lower in-hospital mortality (p = 0.02) and lower transfusion rates (p < 0.001), while re-exploration for bleeding was similar across groups (p = 0.68). After multivariable adjustment, there was no association between hematocrit and postoperative stroke (odds ratio [OR]: 1.00, 95% confidence interval [CI]: 0.99, 1.00, p = 0.79). Compared with normal hematocrit, there was no association between low hematocrit (OR: 1.59, 95% CI: 0.77, 3.28, p = 0.21) or high hematocrit (OR: 2.48, 95% CI: 0.74, 8.29, p = 0.14) and in-hospital mortality.

CONCLUSIONS

Preoperative hematocrit was not associated with stroke or mortality after ATAAD repair. The rheologic effect of hematocrit on cerebral perfusion under deep hypothermia may be minimal.

Moderate hypothermia circulatory arrest as a brain-protective strategy for type A aortic dissection

OBJECTIVES

Brain-protective strategies for acute type A aortic dissection (TAAD) remain controversial. Moderate hypothermia circulatory arrest (MHCA) without cerebral perfusion is not commonly used. However, we aimed to assess its safety and efficacy in 358 patients who underwent hemiarch replacement with MHCA for acute type A aortic dissection at our institution from August 2012 to August 2022.

METHODS

Clinical outcomes were compared according to circulatory arrest time [≤15 min (S group, n = 52) vs ≥16 min (L group, n = 306)]. The primary outcome was postoperative stroke.

RESULTS

The S group had more older patients (72.5 vs 68.8 years; P = 0.04), a greater incidence of carotid artery malperfusion (21% vs 11%; P = 0.043) and a lower body mass index (21.7 vs 23.6 kg/m2; P < 0.01) and hemodynamic instability (3.8% vs 16%; P = 0.02) than the L group. The incidence of postoperative stroke (7.7% vs 12%; P = 0.33) and the rate of 30-day mortality (5.8% vs 6.5%; P = 0.83) did not significantly differ between groups. After adjusting for all potential confounding factors pre- and intraoperatively, there was no significant difference in postoperative outcomes between groups.

CONCLUSIONS

MHCA alone for TAAD had comparable postoperative outcomes with circulatory arrest times under and over 15 min. However, longer arrest times were associated with a higher risk of stroke.

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.

Preservation versus replacement of the aortic root for acute type A aortic dissection

OBJECTIVE

To determine the impact of aortic root preservation versus aortic root replacement (ARR) after acute type A aortic dissection (ATAAD) repair.

METHODS

In this observational study of consecutive aortic surgeries between 2007 and 2021, patients with ATAAD were identified via a prospectively maintained institutional database and were stratified by root preservation versus ARR (including valve-sparing and complete ARR). Kaplan-Meier survival estimation and multivariable Cox regression analysis were performed.

RESULTS

Among the 601 patients underwent aortic arch reconstruction for ATAAD, 370 (61.6%) underwent root preservation and the other 231 (38.4%) underwent ARR, with a median follow-up of 6.3 years (interquartile range, 3.8-9.6 years). Cardiopulmonary bypass and ischemic times were longer in the ARR group, but intraoperative variables were otherwise similar between the groups, including cannulation strategy and extent of distal repair. There were no between-group differences in postoperative outcomes, including operative mortality, stroke, mechanical ventilation time, renal failure, reexploration for bleeding, and total length of stay. At a 1-year follow-up, the incidence of aortic regurgitation (moderate or greater) was similar in the 2 groups. On multivariable Cox regression, ARR was not associated with improved long-term survival compared with root preservation (hazard ratio, 1.13; 95% confidence interval, 0.82-1.56; P = .44). Late reinterventions on the aortic root or valve were similar in the 2 groups and was 2.0% for the overall cohort.

CONCLUSIONS

These findings suggest that aortic root preservation may achieve similar midterm outcomes as ARR after ATAAD repair.

Reinterventions After Repair of Acute Type A Aortic Dissection: Incidence, Outcomes, and Risk Factors

BACKGROUND

This study reports the incidence, outcomes, and risk factors for aortic reinterventions after repair of acute type A aortic dissection (ATAAD).

METHODS

This was an observational study of aortic operations from 2010 to 2021. All patients with ATAAD undergoing open aortic arch reconstruction were included. Patients were dichotomized by the need for reintervention, which included reinterventions proximal to or distal to the index aortic repair. Propensity matching was used to determine the impact of reintervention on long-term outcomes. The cumulative incidence function for reintervention was estimated, and multivariable Fine-Gray analysis was performed to identify variables associated with reintervention, with death treated as a competing event.

RESULTS

We identified 601 patients undergoing surgery for ATAAD. An aortic reintervention was required in 71 (11.8%), comprising a proximal reintervention in 12 patients, a distal reintervention in 56, and both in 3. The cumulative incidence of reintervention was 11.6% (95% CI, 8.9%-14.6%) at 5 years and was 16.0% (95% CI, 12.2%-20.3%) at 10 years, with a median time to reintervention of 4.0 years (interquartile range, 0.9-7.5 years). Multivariable analysis using the Fine-Gray method showed no operative variables were associated with reinterventions. Among the 71 reinterventions, there were 4 (5.6%) operative deaths. After propensity matching, there was no difference in Kaplan-Meier survival estimates across each group (P = .138 by log-rank statistics).

CONCLUSIONS

The cumulative incidence of aortic reintervention after ATAAD repair was reasonably low (16% at 10 years), reinterventions were relatively safe (6% operative mortality), and reinterventions did not significantly impact long-term survival.

Outcomes of emergency surgery for acute type A aortic dissection complicated by malperfusion syndrome

OBJECTIVE

The study objective was to determine the impact of malperfusion syndrome on in-hospital mortality and midterm survival after emergency aortic arch reconstruction for acute type A aortic dissection.

METHODS

This was an observational study of aortic surgeries from 2010 to 2018. All patients with acute type A aortic dissection undergoing open aortic arch reconstruction were included. Patients were dichotomized by the presence or absence of malperfusion syndrome and were analyzed for differences in short-term postoperative outcomes, including morbidity and in-hospital mortality. Kaplan-Meier survival estimation and multivariable Cox analysis were performed to identify variables associated with survival.

RESULTS

A total of 467 patients undergoing aortic arch reconstruction for acute type A aortic dissection were identified, of whom 332 (71.1%) presented without malperfusion syndrome and 135 (28.9%) presented with malperfusion syndrome. Patients with malperfusion syndrome had higher in-hospital mortality (21.5% vs 5.7%) than patients without malperfusion syndrome. After multivariable adjustment, malperfusion syndrome was associated with worse survival (hazard ratio, 2.43, 95% confidence interval, 1.61-3.66, P < .001) compared with patients without malperfusion syndrome. The predicted risk of mortality increased as the number of malperfused vascular beds increased. Patients with coronary malperfusion syndrome and neuro-malperfusion syndrome had reduced survival compared with the rest of the cohort (P < .05).

CONCLUSIONS

Malperfusion syndrome is associated with higher in-hospital mortality and reduced survival for patients with acute type A aortic dissection, with the risk of mortality increasing as the number of malperfused vascular beds increases. Coronary malperfusion syndrome and neuro-malperfusion syndrome may represent a high-risk subgroup of patients presenting with acute type A aortic dissection complicated by malperfusion syndrome. Finally, malperfusion syndrome may benefit from immediate surgical intervention to restore true lumen perfusion, as opposed to operative delay.

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.

Outcomes of Surgical Aortic Valve Replacement After Transcatheter Aortic Valve Implantation

Few studies have reported their experience in explantation of a transcatheter heart valve. We found 2,100 patients who underwent transcatheter aortic valve implantation (TAVI) from 2013 through 2021. Of 2,100, a total of 17 patients underwent surgical aortic valve replacement after TAVI, including surgical bailout. The mean age was 78.3 years. Co-morbidities were very frequent, including coronary artery disease (70.6%), atrial fibrillation (52.9%), cerebrovascular disease (47.1%), and pulmonary hypertension (41.2%). A history of cardiac surgery was observed in 6 patients (35.3%). The mean predicted risk of mortality at the time of TAVI was 7.7%. Surgical bailout was the most common indication of valve explantation (n = 8, 47.1%), followed by infective endocarditis (n = 4, 23.5%) and paravalvular leak (n = 2, 11.8%). The valve-in-valve TAVI was not feasible because of endocarditis, paravalvular leak, and history of valve-in-valve TAVI. Overall, 13 (76.5%) were performed urgently or emergently, and 10 (58.9%) required aortic root reconstruction. The mean cardiopulmonary bypass time was 158.5 minutes. In-hospital mortality was 41.2%. Transcatheter heart valve explantation continues to be rare; however, these data will continue to be informative as TAVI explantations will become more common with time.

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.

Does deep hypothermic circulatory arrest with versus without retrograde cerebral perfusion affect the outcomes after proximal aortic arch aneurysm and acute type A aortic dissection repair? Different pathologies and cerebral protection techniques with similar results

Hypothermic circulatory arrest is used for proximal and total aortic arch correction in patients with aortic arch aneurysm and acute or chronic type A aortic dissection. Different cerebral perfusion techniques have been proposed for reducing morbidity and mortality rate. The study of Arnaoutakis et al. showed that deep hypothermic circulatory arrest with or without retrograde cerebral perfusion for proximal aortic aneurysm and acute type A aortic dissection correction had similar results with regard to morbidity and mortality rate. In addition, the short circulatory arrest time contributes for favorable outcomes of these patients. Although antegrade cerebral perfusion with hypothermic circulatory is widely used by many cardiac surgeons, deep hypothermic circulatory arrest with or without retrograde cerebral perfusion remains an alternative and safe method for brain protection in patients undergoing proximal aortic arch aneurysm or acute type A aortic dissection repair.