Effect of different types of cerebral perfusion for acute type A aortic dissection, unilateral versus bilateral

doi:10.21203/rs.3.rs-22196/v2

Background: Antegrade cerebral perfusion (ACP), including unilateral and bilateral, is most commonly used way for cerebral protection in aortic surgery. There is still no consensus on the superiority of the two methods. Our research was aimed to investigate the clinical effects between u-ACP and b-ACP.

Methods: 321 of 356 patients with type A aortic dissection were studied retrospectively. 124 patients (38.6%) received u-ACP and 197 patients(61.4%) received b-ACP. We compared the incidence of postoperative neurological complications and other collected data between two groups. We also analyzed perioperative variables in order to find the potential associated factors for neurolocial dysfunction (ND).

Results: For u-ACP group, 54 patients (43.5%) had postoperative neurological complications including 22 patients (17.7%) with permanent neurologic dysfunction (PND) and 32 patients (25.8%) with temporary neurologic dysfunction (TND). For b-ACP group, 47 patients (23.8%) experienced postoperative neurological complications including 16 patients (8.1%) of PND and 31 patients (15.7%) of TND. The incidence of PND and TND were significantly different between two groups along with shorter CPB time (p=0.016), higher nasopharyngeal temperature (p≦0.000), shorter ventilation time (p=0.018) and lower incidence of hypoxia (p=0.022). Furthermore, multivariate stepwise logistic regression analysis confirmed that preoperative neurological dysfunction (OR=1.20, P= 0.028), CPB duration (OR=3.21, P=0.002 ) and type of cerebral perfusion (OR=1.48, P=0.017) were strongly associated with postoperative ND.

Conclusions: In our study, we found that b-ACP procedure had shorter CPB time, milder hypothermia, shorter ventilation time, lower incidence of postoperative hypoxia and neurological dysfunction compared to u-ACP. Meanwhile, we discovered the incidence of ND was independently associated with there factors, including preoperative neurological dysfunction, CPB time and type of cerebral perfusion.

General Surgery

Surgery

cerebral protection

unilateral antegrade cerebral perfusion

bilateral antegrade cerebral perfusion

Type A aortic dissection

neurological complications

AORTIC DISSECTION (AD) is one of the most serious cardiac emergencies due to its associated high mortality rates, especially Stanford type A [1, 2]. Presently, surgery is the primary treatment method. The frozen elephant trunk technique is increasingly being used to repair dissections extending over the entire aortic arch. Despite immense improvements in surgical techniques, the operative mortality and complications of type A aortic dissection(AD) remain considerably high [3]. Neurological dysfunction (ND) is a common complication, with a reported rate ranging from 5.5–33.3% of cases [4]. Consequently, it is crucial to implement appropriate measures to prevent cerebral injury.

In recent decades, various kinds of protocols to avoid cerebral damage have been utilized. Advances in these protocols have subsequently improved neurological outcomes for type A AD. Currently, antegrade cerebral perfusion (ACP) has become the standard method of cerebral support. However, there is still a controversy regarding the superiority of either the unilateral ACP (u-ACP) or bilateral ACP (b-ACP) as the most effective perfusion approach [5, 6].

As is well-known, the feasibility of u-ACP for keeping the brain perfused during the circulatory arrest period is based on the integrity of the circle of Willis. Nevertheless, there are several anatomical variations of the circle. The b-ACP approach is a way of providing cerebral perfusion through both sides simultaneously which mimics the physiological conditions. Therefore, we postulated that b-ACP may be more advantageous for cerebral support or other aspects relating to mortality, neurological outcome, and other systemic complications, compared to u-ACP.

We also retrospectively gathered potential variables, according to the Society of Thoracic Surgeons (STS) National Database, aiming at identifying risk factors for postoperative neurological dysfunction in patients with type A AD undergoing total aortic arch replacement.

Study Populations

We retroactively studied 356 patients with type A AD who were admitted to our cardiac surgical intensive care unit after total aortic arch replacement from January 1, 2014 to December 31, 2018. 321 patients undergoing total arch replacement with one of the following manifestations shown on CTA: arch tear, carotid dissection or occlusion, or the presence of an aneurismal arch were included into our researc, of whom 124 underwent a u-ACP (38.6%) and 197 underwent a b-ACP (61.4%). The experimental protocol and informed consent were approved by the Institutional Review Board of our hospital, and all subjects gave informed consent. Among the 321 patients, there were 224 males and 97 females. The mean age was 51.98±9.78 years. All the cases were diagnosed using preoperative computed tomography angiography (CTA) and therapy was conducted within 2 weeks of onset. Preoperative echocardiography was also necessary to evaluate the cardiac function, the exact position of intima rupture, and to assess the condition of the aortic and mitral valves. Every patient underwent total arch replacements. According to the surgery time from onset, we divided patients into three groups: hyper-acute (<24h), acute (24-72h) and subacute (>72h). The concomitant procedures included Bentall procedure, coronary artery bypass grafting (CABG) and Bentall+CABG. The relevant demographic data and surgical strategies were illustrated in Table 1. Preoperative neurological complications were defined as acute neurological dysfunctions from dissection, which included one patient with coma, three with somnolence, one with hemiplegia, and four with monoplegia.

The anesthetic regimen was kept standard. Intravenous (IV) injections of 2.5–5 mg midazolam, 0.2-0.6mg/kg etomidate, 0.1-5ug/kg sufentanil, and 0.6mg/kg rocuronium were performed as the standard anesthetic induction in these patients. Subsequently, tracheal intubations were executed. Anesthesia was maintained by continuous inhalation of sevoflurane, IV injections of dexmedetomidine and rocuronium, combined with theadditional administration of midazolam and sufentanil when necessary.

Operative Technique

All operations were conducted by the same surgical staff. Our operative techniques comprised of cardiopulmonary bypass (CPB), moderate hypothermia (24-28℃) , circulatory arrest, and ACP. Monitoring data included left radial and dorsalis pedis arterial pressures, main arterial pressure (MAP), central venous pressure (CVP), electrocardiography (ECG), blood oxygen saturation (SaO₂), and arterial blood gas (ABG) analysis. Cerebral saturation was monitored with near-infrared spectroscope (NIRS). Prior to December 2015, u-ACP with moderate hypothermia circulatory arrest (24-26℃) was routinely performed to maintain cerebral perfusion. From January 2016, b-ACP was initiated until the end of the study. The temperature of circulatory arrest was gradually increased to 26-28℃. In both groups, right axillary artery with right femoral artery cannulations were conducted to establish CPB. In the u-ACP group, cannulation of the right axillary artery was used for cerebral perfusion. Whereas in the b-ACP group, a right axillary artery cannulation was used along with a 12-F or 14-F balloon-tip catheter in the left common carotid artery.

After CPB was established, we cross-clamped the ascending aorta after the nasopharyngeal temperature dropped to 34℃ or lower. Consequently, cold blood cardioplegia was injected into the coronary ostia antegrade or the coronary sinus retrograde directly to stop the heart. We subsequently made a longitudinal incision on the ascending aorta and the aortic root procedure was performed depending on the severity and extent of the disease; including aortic root formation or Bentall procedure with or without CABG.

When the temperature reached 24℃ to 28℃, all three branches of the aortic arch were separately clamped, and the systemic circulation stopped. In the u-ACP group, cerebral perfusion was provided only by the right axillary artery cannulation. 12 of 124 patients, who immediately switched to b-ACP, were classified as b-ACP group patients. In the b-ACP group, both the right axillary artery and left common carotid artery were used for cerebral protection. Flow rates of 5 ml/kg/min to 10ml/kg/min were used for ACP, with perfusion pressures ranging from 50mmHg to 80 mmHg. A stented elephant trunk was inserted into the proximal descending aorta and attached to the distal end of the graft. Subsequently, systemic circulation of the lower body was restarted via the right femoral artery. For the u-ACP group, anastomosis of the left common carotid artery was done at first, in order to restore left cerebral perfusion. Afterwards, the proximal aortic root was anastomosed to the prosthetic graft to restore systemic circulation and the temperature increased progressively. The left subclavian artery and innominate artery were sequentially anastomosed to the prosthetic graft. For the b-ACP group, we initially anastomosed the left subclavian artery to the prosthetic graft, followed by the left common carotid artery, proximal aortic root and innominate artery respectively.

Statistical Analysis

All of the perioperative data were analyzed distinctively between two groups (See Tables 2 and 3). The postoperative variables consisted of 30-day mortality rate, ventilation time (h), permanent neurological dysfunction (PND), temporary neurological dysfunction (TND), acute kidney injury (AKI, referring to elevated serum creatinine concentration >1.5 times of baseline or urine volume< 0.5ml/kg/h for 6 hours within 48 hours after surgery), hypoxia (PaO₂/FiO2 <200 with PEEP≥5cmH2O within 72 hours after surgery), and postoperative bleeding volume within 24 hours of surgery. Patients with neurological symptoms had to be examined by CT scans to confirm the diagnosis. PND was defined as the presence of permanent neurological deficits persisting after being discharged with focal or global cerebral lesions confirmed by CT or MRI, including monoplegia, hemiplegia, paraplegia and coma, confirmed by CT or MRI. TND included transient ischemic attack (TIA) and reversible neurological deficits such as delirium, confusion and agitation with no new lesions on CT. All the diagnoses of stroke were adjudicated by a neurologist who was blinded.

Continuous variables were expressed as mean±SD; categorical data were expressed as proportions. The T test or Mann-Whitney test were used to compare continuous variables while categorical data were compared using the χ² test or the Fisher exact test. We divided the patients into two groups (ND vs non-ND). All potential risk variables were analyzed for significance. For factors with P-values <0.05, the multivariable logistic regression model was employed to further identify independent risk factors.

Intraoperative Data

There were no significant differences in terms of rates of concomitant surgery, including the Bentall procedure, CABG, and Bentall+CABG between the two groups (Table 2). However, we found that the CPB durations and nasopharyngeal temperatures during the circulatory arrest period were considerably different.

Mortality rates and Morbidities

After meticulous comparisons of the postoperative data, we didn’t find differences in the 30-day mortality rates, incidence of postoperative renal failure, or bleeding volume >1 L within 24 hours of surgery. Compared to the u-ACP group, the b-ACP group patients displayed shorter ventilation times (44.03±28.74 vs. 62.26±46.42; p=0.018) , and overall lower incidence of hypoxia (16.4% vs. 27.9%; p = 0.037) (See Table 3).

Neurological Events

We compared the postoperative neurological complications between the two groups (See Figure 1). For the u-ACP group, PND was observed in 22 patients (17.7%): paraplegia (n = 2), monoplegia (n = 4), hemiplegia (n = 11), and coma (n = 5). TND was observed in 32 patients (25.8%): delirium (n = 23), TIA (n = 2), and confusion and agitation (n = 7). Meanwhile for the b-ACP group, a total of 16 patients (8.1%) with PND were observed: paraplegia (n = 1), hemiplegia (n = 9), monoplegia (n = 4), and coma (n = 2). Whilst 31 patients (15.7%) with TND were observed: delirium (n= 25), confusion and agitation (n = 6), and no TIA. The incidence of PND and TND were undoubtedly different between the two groups (See Table 4).

Furthermore,we divided the patients into different groups based on the incidence of postoperative neurological dysfunction: ND and non-ND groups. The results of univariate analyses of all the potential risk variables were listed in Table 5. All variables with P values <0.05 were included in the multivariable analysis model. Our study showed that preoperative neurological dysfunction (OR=1.20, P= 0.028), CPB duration (OR=3.21, P=0.002 ) and type of cerebral perfusion (OR=1.48, P=0.017) were independent risk factors for genesis of ND (Table 6).

We made a comparison for two cerebral perfusion methods with respect to a set of clinical outcomes. We discovered that patients in the b-ACP group had shorter CPB times, higher permissive arrest temperatures, shorter ventilation times, and lower incidences of postoperative hypoxia and ND. ND is a serious postoperative complication of acute type A AD[7] with incidence ranging from 0-32.8% [8]. Despite the relatively frequent occurrence of ND in type A AD patients, its major risk factors remain uncertain. Therefore, we analyzed various potential factors retrospectively and found that the preoperative neurological function, CPB time, and type of cerebral perfusion chosen were independent risk factors for postoperative neurological dysfunction. Therefore, we may reduce the occurrence of postoperative ND by shortening the CPB time and choosing the most efficient cerebral perfusion method. The relationship between postoperative neurological complications and the intraoperative ACP method used is further discussed here.

Hypothermic circulatory arrest combined with ACP has been recognized as the first choice for cerebral protection in aortic arch surgery, and were used worldwide [9,10]. This technique yielded the best results; mostly improved short-term or long-term outcomes. Nevertheless, the use of u-ACP vs b-ACP remains a subject of debate. Previously, we routinely used right axillary artery cannulation for u-ACP in type A AD operations. Its main advantage being that it involves less risk of dissection or atherosclerosis in the right axillary artery. Besides, the isolation and cannulation procedure is much easier this way. Nowadays, along with the tremendous improvements in operative technology, intubation methods, and clearer determination of anatomical locations, a substantial body of evidence suggests the exact effect of b-ACP with advantages of shorter CPB time, permissive milder hypothermia, lower incidence of hypoxia and ND[11,12]. The possible reasons can be summarized as follows.

We previously explained the surgical procedures with u-ACP or b-ACP in detail. The anastomosis sequence of the three branches of the aortic arch is different in the two groups. For the u-ACP group, we initially anastomosed the left common carotid artery to restore the physiological status of the left cerebral perfusion. Anastomosis of the left subclavian artery followed. Actually, initial anastomosis of the left common carotid artery can hinder the subsequent operation on the left subclavian artery by reducing the surgical field, thus making the procedure more challenging and time-consuming. Consequently, the incidence of anastomotic bleeding of the left subclavian artery rose, and our surgeons needed more time and attention to stop the bleeding. The mean CPB time of the u-ACP group was longer than that of the b-ACP group.

The integrity of the circle of Willis is the key for sufficient cerebral perfusion under u-ACP. Nonetheless, there are several anatomical variations of the circle, not to mention cases of vascular dysplasia or deficiency of vascular branches. Studies have proven that the proportion of individuals with intact circles of Willis comprise 21-25% of the population, and the variation rate can be as high as 50%, especially in the posterior circulation [13,14]. However, some patients are unable to undergo CTA, magnetic resonance angiography (MRA), or digital subtraction angiography (DSA) to determine the integrity of the circle of Willis before surgery due to the severity of the disease itself or for other reasons. Therefore, b-ACP can assure continuous bilateral cerebral perfusion regardless of the integrity of the circle of Willis. Harrer et al. [15] reported that the left cerebral oxygen saturation increased by about 19% when the perfusion approach was switched from u-ACP to b-ACP.

With the advent of deep hypothermic circulatory arrest (DHAC) into clinical practice by Griepp and associates in the 1970s, the outcome of arch surgery was remarkably improved. Hypothermia provides neurological protection essentially by decreasing the global cerebral metabolic rate and increasing the cerebral tolerance to circulatory arrest. Hypothermia can also reduce temperature-dependent release and extracellular levels of excitatory neurotransmitters such as glutamate, thereby inhibiting pro-apoptotic activity and reducing the level of free radicals and inflammatory cytokines [16]. Earlier protocols have utilized temperatures as low as 14℃ with the belief that lower temperature sufficiently diminishes cerebral metabolic demands. In recent years, surgeons began to question the limitations of DHAC. Ehrlich et al. reported that further reduction of temperature beyond 18℃ did not further decrease the oxygen requirement in the brain. As a matter of fact, it led to greater cerebrovascular homeostasis impairment and reduced cerebral perfusion [17]. Several experts have cautioned against DHAC because of its related hazards of prolonged CPB time, greater coagulopathy and aggravated inflammatory responses. Recent studies from high-volume aortic centers have demonstrated excellent results of moderate levels of hypothermia combined with ACP [18,19]. With the increase of the circulatory arrest temperature, the tolerance of cerebral tissue to ischemia or hypoxia reduced. In the b-ACP group, both cerebral hemispheres were perfused directly through cannulation, permitting better perfusion and a higher arrest temperature compared with the u-ACP group. The higher circulatory arrest temperature causes less impaired cerebrovascular homeostasis, thereby avoiding hypo-cerebral or hyper-cerebral perfusion via the physiological regulation of the cerebral vessels themselves. Finally, the higher temperature during circulatory arrest allows for shorter cooling and rewarming time, substantially reducing the CPB time.

Study Limitations

This study has some inevitable limitations. First the study is a retrospective review for 5 years, and we cann’t exclude the influence of era bias. Second, this study only represent a single-center experience and not a multicenter experience. So we need to design a multicenter prospective analysis in the future in order to verify our results.

The b-ACP procedure had some advantages compared to u-ACP, including reduced incidence of postoperative neurological dysfunction, shorter ventilation time, shorter CBP time, and lower incidence of postoperative hypoxia according to our research. Furthermore, we analyzed the potential risk factors for ND and found that preoperative neurological dysfunction, CPB duration and perfusion method were independent risk factors for the generation of ND. So we may reduce the incidence of ND by modifying the adjustable factors including CPB time and more appropriate cerebral perfusion method.

AD Aortic Dissection

ND Neurological Dysfunction

ACP Antegrade Cerebral Perfusion

u-ACP unilateral Antegrade Cerebral Perfusion

b-ACP bilateral Antegrade Cerebral Perfusion

CPB Cardiopulmonary Bypass

MAP Mean Arterial Pressure

CVP Central Venous Pressure

ECG Electrocardiography

SaO₂ Blood Oxygen Saturation

ABG Arterial Blood Gas

NIRS Near-Infrared Spectroscope

PND Permanent Neurological Dysfunction

TND Temporary Neurological Dysfunction

AKI Acute Kidney Injury

TIA Transient Ischemic Attack

DHAC Deep Hypothermic Circulatory Arrest

Ethics approval and consent to participate: The experimental protocol and informed consent were approved by the Institutional Review Board of our hospital-Qilu hospital of Shandong university. And all patients involved in this study gave their informed consent verbally. Since our research was a retrospective one and we just collected patients’ data retrospectively without any intervention that could influence patients’ clinical outcome.

Consent for publication: Not applicable.

Availability of data and materials: The datasets analysed during the current study are available from the corresponding author on reasonable request.

Competing interests: We declare that there are no conflicts of interest to the manuscript submitted. We do not have any commercial or personal relationships with other people or organizations in connection with our work.

Funding: No funding.

Acknowledgement

In writing this paper, I have benefited from the presence of my teachers and colleagues. They generously helped me collect materials I needed and made many invaluable suggestions. I hereby extend my grateful thanks to them for their kind help. Particularly, I am deeply indebted to Professor Xinyan Pang, who guided me throughout my writing of this thesis. He carefully read the whole draft and offered painstaking and precious criticism. His standards of academic excellence have made my revision and exciting and gratifying experience. I also wish to sincerely thank my director, whose brilliant ideas and perceptive observations have proved immensely constructive. Furthermore, none of this would have been possible without the help of those individuals and organizations hereafter mentioned with gratitude: our department and its staff, the department of cardiovascular surgery of Qilu hospital of Shandong university and its staff.

Author's Contributions

No.	Author’s name	contributions to the article
1.	LZQ	conceptualization, data curation, formal analysis, investigation, methodology and writing
2.	WC	conceptualization, data curation, investigation and methodology
3.	ZXQ	conceptualization, methodology and review
4.	WSM	conceptualization and review
5.	FCC	data curation, investigation and methodology
6.	PXY	conceptualization, formal analysis, investigation, methodology and writing

[1] Nienaber C.A., Eagla K.A.. Aortic dissection: new frontiers in diagnosis and management: Part I: from etiology to diagnostic strategies. Circulation. 2003; 108(5): 628-35.

[2] Rajendra H. Mehta, Toru Suzuki, Peter G. Hagan, Eduardo Bossone, Dan Gilon, Alfredo Llovet, Luis C. Maroto, Jeanna V. Cooper, Dean E. Smith, William F. Armstrong, Christoph A. Nienaber, Kim A. Eagle. Predicting death in patients with acute type A aortic dissection. Circulation. 2002;105(2): 200—6.

[3] Tsai TT, Trimarchi S, Nienaber CA. Acute aortic dissection: perspectives from the International Registry of Acute Aortic Dissection (IRAD). Eur J Vasc Endovasc Surg. 2009;37:149-59.

[4] Apostolakis E, Koletsis EN, Dedeilias P, Kokotsakis JN, Sakellaropoulos G, Psevdi A, et al. Antegrade versus retrograde cerebral perfusion in relation to postoperative complications following aortic arch surgery for acute aortic dissection type A. J Card Surg. 2008;23:480-7.

[5] Kazui T, Yamashita K, Washiyama N, Terada H, Bashar AH, Suzuki K, et al. Aortic arch replacement using selective cerebral perfusion. Ann Thorac Surg. 2007;83:S796-8.

[6] Olsson C, Thelin S. Antegrade cerebral perfusion with a simplified technique: unilateral versus bilateral perfusion. Ann Thorac Surg. 2006;81:868-74.

[7] Peterson MD, Mazine A, El-Hamamsy I, Manlhiot C, Ouzounian M, MacArthur RG, et al. Knowledge, attitudes, and practice preferences of Canadian cardiac surgeons toward the management of acute type A aortic dissection. Thorac Cardiovasc Surg. 2015;150:824-31.

[8] Lars Oliver Conzelmann, Isabell Hoffmann, Maria Blettner, Klaus Kallenbach, Matthias Karck, Otto Dapunt, et al. Analysis of risk factors for neurological dysfuction in patients withe acute aortic dissection type A: data from the German Registry for Acute Aortic Dissection Type A (GERAADA). Eur J Cardiothorac Surg. 2012;42:557-65.

[9] Usui A, Ueda Y. Arch first technique under deep hypothermic circulatory arrest with retrograde cerebral perfusion.Multimed Man Cardiothorac Surg. 2007;2007:doi:10.1510.

[10] Milewski RK, Pacini D, Moser GW, Moeller P, Cowie D, Szeto WY, et al. Retrograde and antegrade cerebral perfusion: results in short elective arch reconstructive times. Ann Thorac Surg. 2010;89:1448–57.

[11] Di Eusanio M, Schepens MA, Morshuis WJ, Dossche KM, Di Bartolomeo R, Pacini D, et al. Brain protection using antegrade selective cerebral perfusion: a multicenter study. Ann Thorac Surg. 2003;76:1181–9.

[12] Kamiya H, Hagl C, Kropivnitskaya I, Böthig D, Kallenbach K, Khaladj N, et al. The safety of moderate hypothermic lower body circulatory arrest with selective cerebral perfusion: a propensity score analysis. Thorac Cardiovasc Surg. 2007;133:501–9.

[13] Okahara M, Kiyosue H, Mori H, Tanoue S, Sainou M, Nagatomi H. Anatomic variations of the cerebral arteries and their embryology: a pictorial review. Eur Radiol. 2002;12:2548–61.

[14] Wiesława Klimek-Piotrowska, Monika Rybicka, Aleksandra Wojnarska, Agnieszka Wjtowicz, Mateusz Koziej, Mateusz K Hołda. A multitude of variations in the configuration of the circle of Willis: an autopsy study. Anat Sci Ins. 2016;91:325-33.

[15] Harrer M, Waldenberger F R, Weiss G, Folkmann S, Gorlitzer M, Moidl R, et al. Aortic arch surgery using bilateral antegrade selective cerebral perfusion in combination with near-infrared spectroscopy. European Journal of Cardio-Thoracic Surgery. 2010;38(5):561-7.

[16] Gonzalez-Ibarra FP, Varon J, Lopez-Meza EG. Therapeutic hypothermia: critical review of the molecular mechanisms of action. Front Neurol. 2011;2:4.

[17] Ehrlich M P, McCullough J N, Zhang N, Weisz D J, Juvonen T, Bodian C A, et al. Effect of hypothermia on cerebral blood flow and metabolism in the pig. The Annals of thoracic surgery. 2002; 73(1): 191-7.

[18] Zierer A, El-Sayed Ahmad A, Papadopoulos N, Moritz A, Diegeler A, Urbanski P P, et al. Selective antegrade cerebral perfusion and mild (28℃–30℃) systemic hypothermic circulatory arrest for aortic arch replacement: results from 1002 patients. J Thorac Cardiovasc Surg. 2012;144:1042–9.

[19] Comas GM, Leshnower BG, Halkos ME, Thourani VH, Puskas JD, Guyton RA, et al. Acute type A dissection: impact of antegrade cerebral perfusion under moderate hypothermia. Ann Thorac Surg. 2013;96:2135–41.

Table 1

Demographic and preoperative characteristics

Variable	u-ACP (n=124)	b-ACP (n=197)	P value
Age (year, ±s)	55.38±10.40	54.00±9.37	0.646
Male (n,%)	85(68.5%)	139(70.6%)	0.822
BMI (kg/m², ±s)	24.58±1.25	25.21±1.44	0.148
Hypertension (n,%)	94(76.3%)	157(80.1%)	0.615
Diabetes mellitus (n,%) COPD (n,%) Cerebrovascular disease history (n,%)	16(12.9%) 3(2.4%) 23(18.5%)	43(21.8%) 7(3.6%) 37(18.8%)	0.433 0.746 0.958
Renal dysfunction (n,%)*	5(4.0%)	12(6.1%)	0.423
Hemodynamic instability	4(3.2%)	9(4.6%)	0.552
Preoperative neurological complication (n, %) Preoperative intubation (n, %) LVEF<0.4 (n, %)	5(4.0%) 6(4.8%) 4(3.2%)	11(5.6%) 10(5.1%) 10(5.1%)	0.534 0.666 0.578

u-ACP, unilateral antegrade cerebral perfusion; b-ACP, bilateral antegrade cerebral perfusion; COPD, chronic obstructive pulmonary disease; * A serum creatinine level >97umol/L is considered to indicate renal dysfunction. Bold values indicate significance at p﹤0.05

Table 2

Intraoperative data

Variable	u-ACP (n=124)	b-ACP (n=197)	P
CPB duration(min, ±s)	260.07±76.79	235.79±46.60	0.016
Aortic cross-clamping duration(min, ±s)	154.53±36.50	154.94±33.75	0.946
Circulatory arrest time (min, ±s) nasopharyngeal temperature (℃, ±s) Concomitant procedures (n, %)	26.60±6.78 24.92±0.28	25.62±6.31 27.09±1.22	0.384 0.000
Bentall	25(20.2%)	47(23.9%)	0.703
CABG	9(7.3%)	18(9.1%)
Bentall+CABG	7(5.6%)	13(6.6%)
Surgery time (n,%)
Hyper-acute (<24h)	24(19.4%)	35(17.8%)	0.914
Acute (24-72h)	82(66.1%)	131(66.5%)
Subacute (>72h)	18(14.5%)	31(15.7%)

u-ACP, unilateral antegrade cerebral perfusion; b-ACP, bilateral antegrade cerebral perfusion; CPB, cardiopulmonary bypass; CABG, coronary artery bypass grafting; Bold values indicate significance at p﹤0.05

Table 3

Postoperative data

Variable

u-ACP (n=124)

b-ACP (n=197)

P

Drainage volume within 24 hours>1L (n, %)

Ventilation time(h, ±s)

Hpoxia( n,%)

AKI( n,%)

PND( n,%)

TND( n,%)

22(17.7%)

62.26±46.42

34(27.4%)

18(14.5%)

22(17.7%)

32(25.8%)

27(13.7%)

44.03±28.74

33(16.8%)

22(11.1%)

16(8.1%)

31(15.7%)

0.328

0.018

0.022

0.376

0.009

0.027

ICU stay(d, ±s)

30-day mortality( n,%)

18.73±5.67

12(9.7%)

17.10±5.18

10(5.1%)

0.447

0.112

u-ACP, unilateral antegrade cerebral perfusion; b-ACP, bilateral antegrade cerebral perfusion; AKI, acute kidney injury; PND, permanent neurologic dysfunction; TND, temporary neurologic dysfunction; Bold values indicate significance at p﹤0.05

Table 4

Description of ND between u-ACP and b-ACP groups

ND	u-ACP (n=124)	b-ACP (n=197)
PND	22(17.7%)	16(8.1%)
Paraplegia Monoplegia Hemiplegia Coma TND Delirium TIA	2(1.6%) 4(3.2%) 11(8.9%) 5(4.0%) 32(25.8%) 23(18.5%) 2(1.6%)	1(0.5%) 4(2.0%) 9(4.6%) 2(1.0%) 31(15.7%) 25(12.7%) 0(0%)
Confusion and Agitation	7(5.6%)	6(3.0%)

u-ACP, unilateral antegrade cerebral perfusion; b-ACP, bilateral antegrade cerebral perfusion; PND, permanent neurologic dysfunction; TND, temporary neurologic dysfunction

Table 5

Univariate analysis of perioperative risk factors of postoperative ND in patients with type A aortic dissection

Variable	ND(n=101)	Non-ND(n=220)	P
Preoperative variables
Age (year, ±s)	56.70±9.91	53.83±9.75	0.422
Male (n,%)	73(73.7%)	155(69.8%)	0.475
Education level (year, ±s)	10.61±5.30	11.23±4.85	0.651
Tobacco use (n,%)	52(52.5%)	108(48.6%)	0.521
Alcohol use (n,%)	20(20.2%)	37(16.7%)	0.444
Barrier of hearing or language (n,%)	3(3.0%)	7(3.2%)	1.000
Hypertension (n,%)	87(87.9%)	168(75.7%)	0.012
Diabetes mellitus (n,%) COPD (n,%)	23(23.2%) 4(4.0%)	36(16.2%) 6(2.7%)	0.134 0.505
Cerebrovascular disease history (n,%) Peripheral arterial disease (n,%) Renal dysfunction (n,%) LVEF<0.4 (n,%) Preoperative neurological dysfunction (n,%) Preoperative intubation (n,%) Preoperative cardiac arrhythmia (n,%)	26(26.3%) 7(7.1%) 9(9.1%) 5(5.1%) 10(9.9%) 9(8.9%) 8(7.9%)	34(15.3%) 11(5.0%) 8(3.6%) 9(4.1%) 6(2.7%) 7(3.2%) 11(5%)	0.020 0.447 0.043 0.684 0.005 0.024 0.273
Intraoperative variables
Concomitant procedures (n,%) Bentall CABG Bentall+CABG	29(28.7%) 15(14.9%) 10(9.9%)	43(19.5%) 12(5.5%) 10(4.5%)	0.358
CPB duration (min, ±s)	259.93±69.94	234.48±49.24	0.009
Aortic cross-clamping duration (min, ±s)	157.96±37.17	153.25±33.11	0.418
Circulatory arrest time (min, ±s) Type of cerebral perfusion (u-ACP, %)	27.06±6.05 50(49.5%)	25.33±6.59 74(33.6%)	0.112 0.007
Nasopharyngeal temperature (℃, ±s)	26.11±1.49	26.60±1.38	0.039
Blood transfusion>1L(n,%)	25(24.8%)	34(15.5%)	0.046
Postoperative variables
Postoperative drainage volume within 24 hours (>1L) (n,%)	15(14.9%)	16(7.3%)	0.033
AKI ( n,%)	16(15.8%)	25(11.4%)	0.264
Hemoglobin (g/L, ±s)	93.25±10.39	100.50±9.35	0.180
Cardiac arrhythmia ( n,%)	21(50.0%)	36(19.7%)	0.335

Bold values indicate significance at p﹤0.05

Table 6

Multivariate stepwise logistic regression analysis for predictors of postoperative ND in patients with type A aortic dissection

Variable	Regression coefficient	OR(95% CI)	P
Preoperative neurological dysfunction^a	0.391	1.20(1.07-1.36)	0.028
CPB duration ^b	1.501	3.21(1.43-5.72)	0.002
Type of cerebral perfusion ^b	0.660	1.48(1.07-2.04)	0.017

^a Preoperative variables

^b Intraoperative variables

Effect of different types of cerebral perfusion for acute type A aortic dissection, unilateral versus bilateral

Status:

Journal Publication

Version 2

Abstract

Figures

Background

Methods

Results

Discussion

Conclusions

List Of Abbreviations

Declarations

References

Tables

Status:

Journal Publication

Version 2