Incomplete Circle of Willis and Right Axillary Artery Perfusion

Meta-analysis: Bilateral and Unilateral Cerebral Perfusion in Type A Dissection

BACKGROUND

 This meta-analysis compared the outcomes of bilateral cerebral perfusion (BCP) and unilateral cerebral perfusion (UCP) in aortic surgery for acute type A aortic dissection.

METHODS

 A systematic literature search identified 12 studies involving 4,547 patients. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated to analyze perioperative characteristics, short-term mortality rates, and postoperative neurological complications.

RESULTS

 No significant differences were found between the BCP and UCP groups in terms of cardiopulmonary bypass time, aortic cross clamp time, lowest body temperature, and lower body circulatory arrest time. Short-term mortality rates (OR [95% CI] = 0.87 [0.64-1.19], p = 0.40) and permanent neurological deficits (OR [95% CI] = 1.01 [0.69-1.47], p = 0.96) were comparable between the groups. However, subgroup analysis of studies exclusively involving total arch replacement showed a lower short-term mortality rate (OR [95% CI] = 0.42 [0.28-0.63], p < 0.01) and permanent neurological deficits (OR [95% CI] = 0.53 [0.30-0.92], p = 0.03) in the BCP group. The BCP group also had a lower rate of temporary neurological deficits (OR [95% CI] = 0.70 [0.53-0.93], p = 0.01), particularly in studies exclusively involving total arch replacement (OR [95% CI] = 0.58 [0.40-0.85], p < 0.01).

CONCLUSION

 This meta-analysis suggests that BCP and UCP yield comparable outcomes. However, BCP may be associated with lower short-term mortality rates and reduced incidence of neurological complications, particularly in cases requiring total arch replacement. BCP should be considered as a preferred cerebral perfusion in specific patient populations.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Prediction of cerebral perfusion pressure during carotid surgery - A computational fluid dynamics approach

BACKGROUND

Maintaining cerebral perfusion pressure in the brain when a carotid artery is closed during vascular surgery is critical for avoiding intraoperative hypoperfusion and risk of ischemic stroke. Here we propose and evaluate a method based on computational fluid dynamics for predicting patient-specific cerebral perfusion pressures at carotid clamping during carotid endarterectomy.

METHODS

The study consisted of 22 patients with symptomatic carotid stenosis who underwent carotid endarterectomy (73 ± 5 years, 59-80 years, 17 men). The geometry of the circle of Willis was obtained preoperatively from computed tomography angiography and corresponding flow rates from four-dimensional flow magnetic resonance imaging. The patients were also classified as having a present or absent ipsilateral posterior communicating artery based on computed tomography angiography. The predicted mean stump pressures from computational fluid dynamics were compared with intraoperatively measured stump pressures from carotid endarterectomy.

FINDINGS

On group level, there was no difference between the predicted and measured stump pressures (-0.5 ± 13 mmHg, P = 0.86) and the pressures were correlated (r = 0.44, P = 0.039). Omitting two outliers, the correlation increased to r = 0.78 (P < 0.001) (-1.4 ± 8.0 mmHg, P = 0.45). Patients with a present ipsilateral posterior communicating artery (n = 8) had a higher measured stump pressure than those with an absent artery (n = 12) (P < 0.001).

INTERPRETATION

The stump pressure agreement indicates that the computational fluid dynamics approach was promising in predicting cerebral perfusion pressures during carotid clamping, which may prove useful in the preoperative planning of vascular interventions.

Efficacy of pump-controlled selective antegrade cerebral perfusion in total arch replacement: A propensity-matched analysis

Background

Pump-controlled selective antegrade cerebral perfusion (PC-SACP) in total arch replacement (TAR) can regulate cerebral flow accurately, which might be beneficial for cerebral protection. However, the safety of PC-SACP for TAR combined with frozen elephant trunk implantation (FET) in patients with acute Type A dissections (ATAAD) is ambiguous.

Methods

A total of 192 patients with ATAAD underwent TAR at our institution from October 2019 to July 2021. The patients were divided into two groups based on PC-SACP used: PC group (SACP carried out by using a separate pump, n = 35) and Control group (SACP carried out as a traditional method, n = 157). Patients under PC-SACP were propensity-score matched to patients without PC-SACP, resulting in 35 pairs of patients.

Results

Preoperative characteristics, including age, gender, weight, and preoperative creatinine level, were similar between the two groups. Cardiopulmonary bypass time, cross-clamp time, circulatory arrest time, and minimum nasopharyngeal temperature did not differ between the two groups. However, SACP time (54 versus 40, P = 0.001) in the PC group was significantly longer than that in the Control group. The incidence of temporary neurologic dysfunction (5.7% versus 8.6, P = 0.643) showed a no significantly lower trend in the PC group compared with the Control group. Other clinical outcomes showed no significant intergroup differences.

Conclusions

PC-SACP in TAR is safe and feasible and might be beneficial for avoiding brain injury caused by “luxury” perfusion.

Aortic arch surgery: what I would have done different? The Kobe/Takatsuki experience

Our current approach towards total arch replacement includes the following: (1) innominate vein mobilization, (2) no neck vessel taping, and no dissection of the vagal nerve, (3) meticulous selection of arterial cannulation site and type of arterial cannula, (4) antegrade cerebral perfusion(ACP)for neuro-protection, utilizing three balloon-tipped cannular from inside the arch, (5) whole-body hypothermia with minimal tympanic temperatures between 20 and 23 °C and minimal rectal temperatures below 30 °C, (6) distal enucleation and felt reinforcement for in zone III distal anastomosis using four branched graft, (7) early re-warming after distal anastomosis with ACP flow adjustment while monitoring brain oxygenation by near-infrared spectroscopy (NIRS) and (8) second anastomosis is proximal and last one is arch vessel reconstruction, (9) maintaining strict fluid balance below 1000 ml by the extracorporeal ultrafiltration method (ECUM) during cardiopulmonary bypass (CPB), with the expectation of more rapid pulmonary functional recovery.

En Bloc Arch Reconstruction With the Frozen Elephant Trunk Technique for Acute Type a Aortic Dissection

Objective: The study objective was to evaluate the effect of en bloc arch reconstruction with frozen elephant trunk (FET) technique for acute type A aortic dissection.

Methods: 41 patients with acute Stanford type A dissection underwent en bloc arch reconstruction combined with FET implantation between April 2018 and August 2020. The mean age of the patients was 46 ± 13 years, and 9 patients were female. One patient had Marfan syndrome. Six patients had pericardial tamponade, 9 had pleural effusion, 5 had transient cerebral ischemic attack, and 3 had chronic kidney disease.

Results: The hospital mortality rate was 9.8% (4 patients). 2 (4.9%) patients had stroke, 23 (56.1%) had acute kidney injury, and 5 (12.2%) had renal failure requiring hemodialysis. During follow-up, the rate of complete false lumen thrombosis was 91.6% (33/36) around the FET, 69.4% (25/36) at the diaphragmatic level, and 27.8% (10/36) at the superior mesenteric artery level. The true lumen diameter at the same three levels of the descending aorta increased significantly while the false lumen diameter reduced at the two levels: pulmonary bifurcation and the diaphragm. The 1-, 2-and 3-year actuarial survival rates were 90.2% [95% confidence interval (CI), 81.2–99.2], 84.2% (95% CI, 70.1–98.3) and 70.2% (95% CI, 42.2–98), respectively.

Conclusions: In patients with acute type A dissection, en bloc arch reconstruction with FET technique appeared to be feasible and effective with early clinical follow-up results. Future studies including a large sample size and long-term follow-up are required to evaluate the efficacy.

Frozen Elephant Trunk Technique in Acute Type A Aortic Dissection: Is It for All?

Acute type A aortic dissection (ATAAD) is an indisputable emergency with very poor outcomes without surgical treatment. Although the aortic arch is often involved in the aortic dissection, its optimal management during surgical therapy remains uncertain. A conservative tear-oriented approach has traditionally been adopted, limiting the procedure to the ascending aorta (or hemiarch) replacement. However, dilation of the residual dissected aorta and subsequent rupture may occur, requiring further intervention in the future. In the last two decades, the frozen elephant trunk (FET) technique has become a valid and attractive option to treat aortic disease when the arch and the thoracic aorta are involved, both in elective and in emergency settings. Here, we report a review of the contemporary literature regarding the short- and long-term outcomes of the FET technique in ATAAD repair.

Direct bilateral carotid artery cannulation can be better strategy for acute aortic dissection involving both carotid arteries

Although acute aortic dissections with bilateral carotid artery involvement are rare, they have serious morbidity and mortality rates. The most important strategy in cases with carotid involvement is to provide adequate cerebral perfusion during cardiopulmonary bypass. In this case, we presented, aortic dissection with bilateral carotid involvement was detected in the patient who was admitted to the emergency department with severe chest pain, vision loss, and left arm monoplegia, and the decision for surgery was made urgently. Selective cerebral perfusion was provided throughout the operation with direct bilateral carotid cannulation, in terms of being the fastest method and providing adequate cerebral flow. During the discharge period, full recovery was achieved in neurological deficits without any sequelae. We think that the technique we have applied in such a difficult and complicated case is the best strategy because it is fast and effective.

RNF213 p.R4810K (c.14429G > A) Variant Determines Anatomical Variations of the Circle of Willis in Cerebrovascular Disease

Introduction

Dysregulation of the RING finger protein 213 (RNF213) gene impairs vascular formation in experimental animal models. In addition, vascular abnormalities in the circle of Willis are associated with cerebrovascular disease. Here, we evaluated the relationship between the East Asian founder variant RNF213 p.R4810K and consequent anatomical variations in the circle of Willis in cerebrovascular disease.

Patients and Methods

The present study is an observational cross-sectional study. It included patients with acute anterior circulation non-cardioembolic stroke admitted to our institution within 7 days of symptom onset or last-known-well from 2011 to 2019, and those who participated in the National Cerebral and Cardiovascular Center Biobank. We compared anatomical variations of the vessels constituting the circle of Willis between RNF213 p.R4810K (c.14429G > A) variant carriers and non-carriers using magnetic resonance angiography and assessed the association between the variants and the presence of the vessels constituting the circle of Willis. Patients with moyamoya disease were excluded.

Results

Four hundred eighty-one patients [146 women (30%); median age 70 years; median baseline National Institutes of Health Stroke Scale score 5] were analyzed. The RNF213 p.R4810K variant carriers (n = 25) were more likely to have both posterior communicating arteries (PComAs) than the variant non-carriers (n = 456) (56% vs. 13%, P < 0.01). Furthermore, variant carriers were less likely to have an anterior communicating artery (AComA) than non-carriers (68% vs. 84%, P = 0.04). In a multivariate logistic regression analysis, the association of RNF213 p.R4810K variant carriers with the presence of both PComAs and the absence of AComA remained significant.

Conclusion

Our findings suggest that the RNF213 p.R4810K variant is an important factor in determining anatomical variations in the circle of Willis.

Neuroprotective strategies in acute aortic dissection: an analysis of the UK National Adult Cardiac Surgical Audit

OBJECTIVES

The risk of brain injury following surgery for type A aortic dissection (TAAD) remains substantial and no consensus has still been reached on which neuroprotective technique should be preferred. We aimed to investigate the association between neuroprotective strategies and clinical outcomes following TAAD repair.

METHODS

Using the UK National Adult Cardiac Surgical Audit, we identified 1929 patients undergoing surgery for TAAD (2011-2018). Deep hypothermic circulatory arrest (DHCA) only, unilateral (uACP), bilateral antegrade cerebral perfusion (bACP) and retrograde cerebral perfusion were used in 830, 117, 760 and 222 patients, respectively. The primary end point was a composite of death and/or cerebrovascular accident (CVA). Generalized linear mixed model was used to adjust the effect of neuroprotective strategies for other confounders.

RESULTS

The use of bACP was associated with longer circulatory arrest (CA) compared to other strategies. There was a trend towards lower incidence of death and/or CVA using uACP only for shorter CA. In particular, primary end point rate was 27.7% overall and 26.5%, 12.5%, 28.0% and 22.9% for CA <30 min and 28.6%, 30.4%, 33.3% and 33.0% for CA ≥30 min with DHCA only, uACP, bACP and retrograde cerebral perfusion, respectively. The use of DHCA only was associated with five-fold [odds ratio (OR) 5.35, 95% confidence interval (CI) 1.36-21.02] and two-fold (OR 1.77, 95% CI 1.01-3.09) increased risk of death and/or CVA compared to uACP and bACP, respectively, but the effect of uACP was significantly associated with CA duration (hazard ratio 0.97, 95% CI 0.94-0.99; P = 0.04).

CONCLUSIONS

In TAAD repair, the use of uACP and bACP was associated with a lower adjusted risk of death and/or CVA when compared to DHCA. uACP can offer some advantage but only for a shorter CA duration.

Type A aortic dissection: involvement of carotid artery and impact on cerebral malperfusion

Acute type A aortic dissection is a surgical emergency and management of such pathology can be complex with poor outcomes when there is organ malperfusion. Carotid artery involvement is present in 30% of patients diagnosed with acute type A aortic dissection, and given its emergency and complex nature, there is much controversy regarding the approach, extent of treatment, and timing of the intervention. It is clear that the occurrence of cerebral malperfusion adds an extra layer of complexity to the decision-making framework for treatment. Standardization and validation of the optimal management approach is required, and this should ideally be addressed with large-scale studies. Nonetheless, current literature supports the need for rapid recognition and diagnosis of acute type A aortic dissection with cerebral malperfusion, immediate and extensive surgical repair, and the appropriate use of cerebral perfusion techniques. This paper aims to discuss the current evidence regarding the impact of carotid artery involvement in both the management and outcomes of acute type A aortic dissection.

Unilateral or bilateral cerebral perfusion in hemiarch replacement: A prospective randomized study

BACKGROUND

We designed a prospective randomized clinical study to compare unilateral and bilateral antegrade cerebral perfusion (ACP) under moderate hypethermia in open distal aortic hemiarch replacement in ascending aortic aneurysm.

METHODS

Forty-two patients were prospectively randomized into two groups; unilateral ACP to Group 1 and bilateral ACP to Group 2. Inclusion criteria were pathological aortic aneurysm in the ascending aorta and/or aortic arch, elective operation, normal preoperative carotid Doppler ultrasonography, and nonexistence of preoperative neurological event. Patients were evaluated with preoperative and postoperative biochemical blood analysis, magnetic resonance imaging (MRI), and neurological disorders. The primary endpoints were permanent neurological disorder and death.

RESULTS

There were 21 patients in each group. Mean age was 56.57 ± 10.06 years in Group 1 and 50.95 ± 15.64 years in Group 2 (p = .170). No significant difference was found according to demographic data. ACP times were significantly higher in bilateral ACP (Group 1: 12.62 ± 5.04 min, Group 2: 18.23 ± 9.04 min, p = .018) whereas cross-clamp time and cardiopulmonary bypass times were not (p = .693 and p = .584 sequentially). Transient neurological disorder was found in seven patients in Group 1 and in 4 patients in Group 2 (p = .484). Postoperative MRI revealed new milimetric ischemic zones in three patients in Group 1 but none in Group 2. No permanent neurological disorder or mortality was seen.

CONCLUSION

The present randomized clinical prospective study could not prove the superiority of one of the technique in cerebral protection probably because, our overall ACP time was too short.

Treatment outcomes for acute type A aortic dissection with patent false lumen in patients over the age of 80

OBJECTIVES

While reports which focus on the outcomes of conservative treatments for acute type A aortic dissection in patients over the age of 80 are worth considering, recently many studies have reported improved outcomes of surgical treatment. Accordingly, we analyzed the outcomes of surgical and conservative treatments for acute type A aortic dissection with patent false lumen in patients over the age of 80.

METHODS

We retrospectively investigated 70 patients over 80 years in age out of 248 consecutive patients with acute type A aortic dissection between January, 2010, and May, 2015. Of the 70 patients, 44 underwent surgical treatments (ascending replacement in 33 and total arch replacement in 11) and 23 patients underwent conservative medical treatments.

RESULTS

In the surgical treatment, the 30-day mortality rate was 14% (6/44) and the rate of morbidity was 34%. And 17 patients (39%) were discharged home without ambulatory assistance. The actuarial survival rates in the surgical treatment group were 83% and 60% at 1 and 3 years, respectively. The in-hospital death rate of conservative medical treatment was 43% (10/23). Only 26% of the patients having had conservative treatment were discharged home without ambulatory assistance. The actuarial survival rate in the conservative medical group was 8.7% at 1 year.

CONCLUSION

Surgical outcomes of acute type A aortic dissection with patent false lumen were satisfactory in patients aged over 80 in this study by meticulously determining operative indications, depending on the background of each patient.

Risk factors of delayed awakening after aortic arch surgery under deep hypothermic circulatory arrest with selective antegrade cerebral perfusion

Background

To determine the risk factors of delayed awakening following aortic arch surgery under deep hypothermic circulatory arrest (DHCA) in combination with selective antegrade cerebral perfusion (SACP).

Methods

We retrospectively analyzed the clinical data of all patients who underwent aortic arch surgery under DHCA + SACP between September 2015 and September 2017 in our hospital. Delayed awakening was defined as recovery of consciousness later than 24 hours after the surgery. Risk factors of delayed awakening were evaluated using multivariate logistic regression analysis.

Results

A total of 168 subjects were included. In-hospital mortality of the overall sample was 19.05% (n=32). Delayed awakening occurred in 76 (45.23%) subjects. Subjects with delayed awakening had older age, hypertension, higher rate of emergency surgery and blood transfusion, and longer cardiopulmonary bypass (CPB) time and myocardial blocking time. Multivariate regression analysis showed emergency surgery (P=0.005) and CPB time >240 min (P<0.001) as risk factors for delayed awakening, even after adjusting potential confounders, including age, hypertension, aortic cross-clamp time and blood transfusion.

Conclusions

In patients undergoing aortic arch surgery under DHCA + SACP, emergency surgery and CPB time >240 min are risk factors for delayed awakening.

Double arterial cannulation strategy for acute type A aortic dissection repair: A 10-year single-institution experience

Background

Repair of acute type A aortic dissection (ATAAD) is a complex and emergent cardiovascular surgery that is associated with high perioperative morbidity and mortality. Each cannulation strategy has different benefits and drawbacks during cardiopulmonary bypass. Using a retrospective study design, we aimed to clarify the safety and efficacy of right axillary artery cannulation in combination with femoral artery cannulation compared to single arterial cannulation for ATAAD repair.

Methods

From January 2007 to July 2017, 476 adult patients underwent ATAAD repair at a single institution. Patients were classified into groups according to their cannulation strategy: the double arterial cannulation (DAC) group (n = 377; 79.2%) or single arterial cannulation (SAC) group (n = 99; 20.8%). Preoperative demographics, surgical information, and postoperative recovery were compared between both groups. Survival and freedom from reoperation rates were analyzed using the Kaplan-Meier actuarial method.

Results

Demographics, comorbidities, and surgical procedures were generally homogenous between the two groups, except for sex, age, and rate of extensive aortic repair. Patients who underwent DAC had lower in-hospital mortality (13.5% vs. 25.3%; P = 0.005) and lower incidence of malperfusion-related complications (18.8% vs. 30.3%; P = 0.011) than those who underwent SAC. During multivariate analysis, SAC was identified as an in-hospital mortality predictor (odds ratio, 2.81; 95% confidence interval, 1.52–5.17; P = 0.001), as were preoperative ventilator support, intraoperative extracorporeal membrane oxygenation installation, and postoperative malperfusion-related complications. Three-year cumulative survival and freedom from reoperation rates were 74.8% and 85.3% for the DAC group and 62.6% and 81.1% for the SAC group, respectively (P = 0.010 and 0.430, respectively).

Conclusions

With acceptable short- and mid-term outcomes, DAC is effective and safe for establishing cardiopulmonary bypass during ATAAD repair.

A functional assessment of the circle of Willis before aortic arch surgery using transcranial Doppler

BACKGROUND

Antegrade selective cerebral perfusion (ASCP) with systemic moderate hypothermia is routinely used as brain protection during aortic arch surgery. Whether ASCP should be delivered unilaterally (u-ASCP) or bilaterally (bi-ASCP) remains controversial.

METHODS

We routinely studied the functional anatomy of the circle of Willis (CoW in all patients scheduled for arch surgery using transcranial color-coded Doppler over a decade. On the basis of these data, we classified observed functional variants as being "safe," "moderately safe," or "unsafe" for u-ASCP.

RESULTS

From January 2005 to June 2015, 1119 patients underwent aortic arch surgery in our institution. Of these, 636 patients had elective surgery performed with ASCP. Preoperative full functional assessment of the CoW was possible in 61% of patients. A functionally complete CoW was found in only 27%. Of all variants, 72% were classified as being safe for u-ASCP, whereas 18% were moderately safe for u-ASCP, and 10% unsafe. Unsafe variants for bi-ASCP were observed in 0.5% of patients.

CONCLUSIONS

The risk of ischemic brain damage due to malperfusion is estimated to be substantially higher during right u-ASCP than during bi-ASCP. Bi-ASCP is therefore highly preferable over u-ASCP if the function of the CoW is unknown. We propose a tailored approach using this full functional assessment preoperatively by applying u-ASCP via the right subclavian artery when considered safely possible, and bi-ASCP when considered a necessity to prevent cerebral malperfusion, and thus thereby try to reduce the embolic stroke risk of ostial instrumentation in bi-ASCP.

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.

Anatomical Variability of the Posterior Communicating Artery

OBJECTIVE

Although posterior communicating artery (PCoA) is a smaller branch of the internal carotid artery, it gives the main contribution in the formation of circle of Willis (CW) by communicating with the internal carotid arterial system and the vertebro-basilar arterial system. The size of PCoA varies frequently. The present work aims to study the PCoA regarding its morphology, morphometry, and symmetry.

MATERIALS AND METHODS

This study was conducted on 170 human cadaveric brains. Brains were dissected carefully and delicately to expose all components of CW, especially PCoA. Morphological variations of PCoA were noted along with its morphometry and symmetry.

RESULTS

Morphological variations of PCoA were aplasia (3.52%), hypoplasia (25.29%), fenestration (0.58%), and persistent fetal pattern (16.47%). In the present study, we found the five different types of terminations of PCoA. Type I termination was the most common type, seen in 92.94% of cases, Type II termination was seen in 1.17%, Type III and Type IV terminations both were seen in 0.58%, and Type V was seen in 1.17%. The mean length of PCoA was 15.9 mm and 15.3 mm on the right and left sides, respectively. The mean diameter of PCoA was 2.1 mm and 1.9 mm on the right and left sides, respectively. Symmetry of PCoA was seen in 65.29% and asymmetric PCoA was seen in 34.70% of cases.

CONCLUSION

The present study provides the complete description of PCoA regarding its morphology, symmetry, and morphometry. Awareness of these anatomical variations is important in neurovascular procedures.

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.

Combined CT angiography of the aorta and craniocervical artery: a new imaging protocol for assessment of acute type A aortic dissection

Background

To investigate the feasibility of combined computed tomography angiography (CTA) of the aorta and craniocervical artery in acute type A aortic dissection (ATAAD) and the value of incremental craniocervical information.

Methods

Combined CTA of head, neck and aorta was performed in patients with suspected aortic dissection and 243 ATAAD patients were analyzed. The image quality and radiation dose were assessed. Valuable craniocervical CTA findings were determined for further surgical analysis.

Results

The mean dose-length product (DLP) was 314.11±29.31 mGy.cm. The image quality of craniocervical arteries were 100% diagnostic. Intimal flap involving carotid arteries was detected in 47% of patients, and significant stenosis of true lumen was observed in 60% of common carotid arteries (CCAs). Hypodensity and hypoplasia/occlusion of carotid arteries were also detected and apprised surgeons. The tortuosity of carotid artery was found in 90.9% of patients. Bilateral antegrade selective cerebral perfusion (ASCP) was performed in 21.1% of aortic arch surgery based on 7 hemodynamic variation types of the circle of Willis (CW) determined by cranial CTA information.

Conclusions

A combined CTA of head, neck and aorta is feasible with low radiation dose and diagnostic image quality. Incremental information on craniocervical pathology and anatomy may be useful for surgery repair of ATAAD.

Long-term outcome and quality of life following emergency surgery for acute aortic dissection type A: a comparison between young and elderly adults

Objectives

Innovations in surgical techniques and perioperative management have continuously improved survival rates for acute aortic dissection type A (AADA). The aim of our study was to evaluate long-term outcome and quality of life (QoL) after surgery for AADA in elderly patients compared with younger patients.

Methods

We retrospectively evaluated 242 consecutive patients, who underwent surgery for AADA between January 2004 and April 2014. Patients were divided into two groups: those aged 70 years and older (elderly group; n  = 78, mean age, 76 ± 4 years) and those younger than 70 years (younger group; n  = 164, mean age, 56 ± 10 years). QoL was assessed with the Short Form Health Survey Questionnaire (SF-36) 1 year after surgery.

Results

The questionnaire return rate was 91.0%. There were already significant differences noted between the two groups with regard to preoperative risk factors on admission. The clinical presentation with a cardiac tamponade was higher in the elderly group (62.8% vs 47.6%; P  = 0.03). Intraoperatively, complex procedures were more common in the younger group (21.3% vs 5.2%; P  = 0.001). Accordingly, cardiopulmonary bypass and cross-clamping times were significantly longer in the younger group. The operative mortality was similar in both groups (3.8% vs 1.2%; P  = 0.33). In the elderly population, 30-day mortality was higher (21.8% vs 7.9%; P  = 0.003). One-year (72% vs 85%), 3-year (68% vs 84%) and 5-year (63% vs 79%) survival rates were satisfactory for the elderly group, but significantly lower compared with the younger group ( P  = 0.008). The physical component summary score also was similar between the groups (39.14 ± 11.12 vs 39.12 ± 12.02; P  = 0.99). However, the mental component summary score might be slightly higher in the elderly group but not statistically significant (51.61 ± 10.73 vs 48.63 ± 11.25; P  = 0.12).

Conclusions

Satisfactory long-term outcome and the general perception of well-being encourage surgery in selected elderly patients with AADA.

Aortic Surgery and Deep-Hypothermic Circulatory Arrest: Anesthetic Update

Aortic arch surgery has become increasingly complex, and novel surgical approaches have been utilized. Efforts aimed at improving neurological outcomes in this patient population have been numerous, with varying degrees of success. This article summarizes the anesthetic considerations for procedures on the aortic arch, including evidence-based outcomes with respect to temperature management, perfusion strategies, hemodynamic goals, adjunct agents, and neuromonitoring.

Optimal temperature management in aortic arch operations

Hypothermic circulatory arrest is a critical component of aortic arch procedures, without which these operations could not be safely performed. Despite the use of hypothermia as a protective adjunct for organ preservation, aortic arch surgery remains complex and is associated with numerous complications despite years of surgical advancement. Deep hypothermic circulatory arrest affords the surgeon a safe period of time to perform the arch reconstruction, but this interruption of perfusion comes at a high clinical cost: stroke, paraplegia, and organ dysfunction are all potential-associated complications. Retrograde cerebral perfusion was subsequently developed as a technique to improve upon the rates of neurologic dysfunction, but was done with only modest success. Selective antegrade cerebral perfusion, on the other hand, has consistently been shown to be an effective form of cerebral protection over deep hypothermia alone, even during extended periods of circulatory arrest. A primary disadvantage of using deep hypothermic circulatory arrest is the prolonged bypass times required for cooling and rewarming which adds significantly to the morbidity associated with these procedures, especially coagulopathic bleeding and organ dysfunction. In an effort to mitigate this problem, the degree of hypothermia at the time of the initial circulatory arrest has more recently been reduced in multiple centers across the globe. This technique of moderate hypothermic circulatory arrest in combination with adjunctive brain perfusion techniques has been shown to be safe when performing aortic arch operations. In this review, we will discuss the evolution of these protection strategies as well as their relative strengths and weaknesses.

Intraoperative 16-Channel Electroencephalography and Bilateral Near Infrared Spectroscopy Monitorization in Aortic Surgery

Transient neurologic dysfunction is common after aortic surgery. Major causes of postoperative complications followed by cardiac surgery are due to hypoperfusion states such as selective cerebral perfusion, embolic debris during cardiopulmonary bypass and ulcerated plaque emboli originated from carotid arteries. Neurologic complications prolong periods of intensive care unit and hospital stay, worsens quality of life and unfortunately they are an important cause of morbidity. Anaesthesia during a carotid and aortic surgery constitutes of providing adequate brain perfusion pressure, attenuating cerebral metabolism by anaesthetic agents and monitoring the cerebral metabolic supply and demand relationship during the intraoperative period. We present a monitoring approach with an intraoperative 16-channel electroencephalography and bilateral near infrared spectroscopy during redo aneurysm of the sinus of Valsalva surgery.

Prolonged Antegrade Cerebral Perfusion via Right Axillary Artery (≥60 min) Does Not Affect Early Outcomes in a Repair of Type A Acute Aortic Dissection

PURPOSE

We aim to investigate whether the duration of antegrade cerebral perfusion (ACP) via right axillary artery with an 8-mm prosthetic graft affects early outcomes in a repair of type A acute aortic dissection (AAD).

METHODS

Over the 24 months from April 2010, a repair of AAD under ACP via the right axillary artery and mild hypothermic circulatory arrest (rectum temperature, 28-30°C) was performed in 34 patients. Mean age was 64.5 ± 13.7 years of age.Preoperative shock status was in three due to cardiac tamponade. Organ malperfusion occurred in 11 patients preoperatively. Mean follow-up period was 9.6 ± 8.4 months and follow-up rate was 100%.

RESULTS

Hospital mortality rate was 8.8%. No newly required hemodialysis and new onset of temporary or permanent neurologic deficits were present in survivors.There were no statistically significant differences of mortality rate, new onset of permanent or temporary neurologic deficits and distal organ dysfunction between ACP duration <60 min and ≥60 min. The 12-month survival was 84.4% ± 6.4%. And, freedom from aorta-related events at 12 and 18 months were 100% ± 0.0% and 88.9% ± 10.5%, respectively.

CONCLUSIONS

The duration of ACP via right axillary artery does not affect early outcomes following a repair of AAD.

Facilitation of bilateral selective antegrade cerebral perfusion with axillary cannulation and retrograde coronary sinus catheter

Over the past several decades, techniques for surgery of the aortic arch have undergone significant evolution. In addition, there have been refinements in the mechanism of cerebral protection utilized intraoperatively. However, significant practice variations in the strategy of antegrade selective cerebral perfusion continue to persist. Here, we describe a simple and easily reproducible technique for selective antegrade cerebral perfusion, utilizing axillary cannulation and retrograde coronary sinus balloon catheters.

Central cannulation by Seldinger technique: a reliable method in ascending aorta and aortic arch replacement

Background

Extensive type A aortic dissections that involve peripheral great vessels can complicate the choice of a cannulation site for cardiopulmonary bypass. We started to employ direct cannulation of the true lumen on the concavity of the aortic arch by Seldinger technique and evaluated the efficacy of this access technique as an alternative arterial inflow target in aortic surgery.

Material/Methods

Twenty-four consecutive patients (mean age: 59±14 years) underwent type A aortic dissection repair using selective antegrade cerebral perfusion. Direct aortic cannulation was used in 14 cases, subclavian access in 6 patients, and femoral entry in 4 patients. Perioperative factors were evaluated to identify the reliability and eventual benefits of direct cannulation method at the aortic arch.

Results

There were no operative deaths and cumulative 30-day mortality rate was 25% (6). Permanent neurological deficits were not observed; in 1 patient transient changes occurred (4%). Time to reach circulatory arrest was the shortest in the direct access group, with mean 27±11 (CI: 20.6–33.3) min vs. 43±22 (28.0–78.0) min (p=0.058) and 32±8 (23.6–40.4) min (p=0.34) by femoral cannulation and subclavian entry, respectively. Direct arch cannulation resulted in the best renal function in the first 72 h after surgery and similar characteristics were observed in lactic acid levels.

Conclusions

Ultrasound-guided direct cannulation on the concavity of the aortic arch using a Seldinger technique is a reliable method in dissection repairs. Prompt antegrade perfusion provides not only cerebral but also peripheral organ and tissue protection, which is an advantage in this high-risk group of patients.

Central versus peripheral arterial cannulation and neurological outcomes after thoracic aortic surgery: meta-analysis and meta-regression of 4459 patients

BACKGROUND

Thoracic aortic surgeries remain with high mortality rates, often associated with postoperative neurological complications. The choice of the right cannulation site is extremely important for suitable blood supply and maintenance of vital functions, especially of the central nervous system.

OBJECTIVES

To compare the influence of central versus peripheral arterial cannulation on neurological outcomes in patients undergoing thoracic aortic surgery through systematic review and meta-analysis.

METHODS

MEDLINE, EMBASE, CENTRAL/CCTR, SciELO, LILACS and reference lists of relevant articles were searched for clinical studies that reported in-hospital neurological outcomes after central or peripheral arterial cannulation during thoracic aortic surgery procedures until December 2013. The principal summary measures were Odds Ratio (OR) for central compared to peripheral arterial cannulation with 95% confidence interval (CI) and p-values considered statistically significant when <0.05. The ORs were combined across studies, using the DerSimonian-Laird random effects model and fixed effects model using the Mantel-Haenszel model--both models were weighted. The meta-analysis was completed using the software Comprehensive Meta-Analysis version 2 (Biostat Inc., Englewood, NJ).

RESULTS

Six studies were identified and included a total of 4459 patients (1180 for central and 3279 for peripheral cannulation). There was no significant difference between the central and peripheral groups regarding neurological outcomes. The meta-regression evidenced no relationship between neurological outcomes and the variables age, sex, previous coronary event, previous neurological event, urgency surgery, cardiopulmonary bypass time, activated clotting time and esophageal temperature with p > 0,05.

CONCLUSION

When it comes to neurological outcomes in patients undergoing thoracic aortic surgery, there was no evidence that argues in favor of any choice of arterial cannulation site, which makes us reject any superiority of one approach over the other in this regard.

Anatomical variations of the circulus arteriosus in cadaveric human brains

Objective. Circulus arteriosus/circle of Willis (CW) is a polygonal anastomotic channel at the base of the brain which unites the internal carotid and vertebrobasilar system. It maintains the steady and constant supply to the brain. The variations of CW are seen often. The Aim of the present work is to find out the percentage of normal pattern of CW, and the frequency of variations of the CW and to study the morphological and morphometric aspects of all components of CW. Methods. Circulus arteriosus of 150 formalin preserved brains were dissected. Dimensions of all the components forming circles were measured. Variations of all the segments were noted and well photographed. The variations such as aplasia, hypoplasia, duplication, fenestrations, and difference in dimensions with opposite segments were noted. The data collected in the study was analyzed. Results. Twenty-one different types of CW were found in the present study. Normal and complete CW was found in 60%. CW with gross morphological variations was seen in 40%. Maximum variations were seen in the PCoA followed by the ACoA in 50% and 40%, respectively. Conclusion. As it confirms high percentage of variations, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in neurovascular procedures.

Morphology of the cerebral arterial circle in the prenatal and postnatal period of Serbian population

BACKGROUND

In the literature, there are descriptions of morphological types of the cerebral arterial circle (CAC) of different human populations around the world, but not the Serbian population. This additionally inspired the authors to present the results of previous and current researches of CAC's configuration in the prenatal, as well as in the postnatal period.

METHOD

The study was performed on CACs of 190 human fetuses and 143 adult cadavers. The caliber and configuration of fetal vessels were examined under the operating microscope, while the same of adults were studied using the ImageJ. Statistical analysis of CACs vessels' calibers was performed. Classification into one of CAC morphological types was based on the presence of hypoplasia of corresponding vessel(s).

RESULTS

There was not only significant difference of the three communicating arteries calibers before and beyond the 16th week of gestation. Calibers of the right pre-communicating part of the posterior cerebral artery and right cerebral part of the internal carotid artery were significantly higher in male than in female adults. There were 13 morphological types of CACs from the prenatal to the postnatal period. Most frequent CAC types were the type I (normal CAC) prenatally and type IV (unilateral hypoplasia of the posterior communicating artery) in the postnatal period. There were not relationships between the cerebral cause of death and a presence of aneurysm.

CONCLUSION

Results of this study will be the basis for future investigation of CACs according to the same or different ages and causes of disease and/or death.

A meta-analysis of deep hypothermic circulatory arrest versus moderate hypothermic circulatory arrest with selective antegrade cerebral perfusion

INTRODUCTION

A recent concern of deep hypothermic circulatory arrest (DHCA) in aortic arch surgery has been its potential association with increased risk of coagulopathy, elevated inflammatory response and end-organ dysfunction. Recently, moderate hypothermic circulatory arrest (MHCA) with selective antegrade circulatory arrest (SACP) seeks to negate potential hypothermia-related morbidities, while maintaining adequate neuroprotection. The present meta-analysis aims to compare postoperative outcomes in arch surgery using DHCA or MHCA+SACP as neuroprotective strategies.

METHODS

Electronic searches were performed using six databases from their inception to January 2013. Two reviewers independently identified all relevant studies comparing DHCA with MHCA+SACP, as defined by a recent hypothermia temperature consensus. Data were extracted and meta-analyzed according to pre-defined clinical endpoints.

RESULTS

Nine comparative studies were identified for inclusion in the present meta-analysis. Stroke rates were significantly lower in patients undergoing MHCA+SACP (P=0.0007, I(2)=0%), while comparable results were observed with temporary neurological deficit, mortality, renal failure or bleeding. Infrequent and inconsistent reporting of systemic outcomes precluded analysis of other systemic outcomes.

CONCLUSIONS

The present meta-analysis indicated the superiority of MHCA+SACP in terms of stroke risk.

Selective cerebral perfusion for cerebral protection: what we do know

Selective antegrade cerebral perfusion (SACP) for aortic arch surgery has evolved considerably since it was first reported. Various pressure rates have been investigated through animal models, as has the effect of warmer perfusate temperatures and hematocrit. Clinical research into pH management, the role of unilateral and bilateral perfusion, and core temperatures have further refined the procedure. We recommend the following protocol for SACP: perfusion pressure between 40-60 mmHg, flow rates between 6-10 mL/kg/min, and perfusate temperature of 20-28 °C; core cooling to 18-30 °C contingent on duration of arrest; alpha-stat pH management; hematocrit between 25-30%; near infrared spectroscopy to monitor cerebral perfusion; and bilateral perfusion when prolonged durations of SACP is anticipated.