Outcome with peripheral versus central cannulation in acute Type A dissection

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1 Interactive CardioVascular and Thoracic Surgery 20 (2015) doi: /icvts/ivv041 Advance Access publication 6 March 2015 ORIGINAL ARTICLE ADULTCARDIAC Cite this article as: Klotz S, Heuermann K, Hanke T, Petersen M, Sievers H-H. Outcome with peripheral versus central in acute Type A dissection. Interact CardioVasc Thorac Surg 2015;20: Outcome with peripheral versus central in acute Type A dissection Stefan Klotz*, Kathrin Heuermann, Thorsten Hanke, Michael Petersen and Hans-Hinrich Sievers Department of Cardiac and Thoracic Vascular Surgery, University Hospital Luebeck, Luebeck, Germany * Corresponding author. Department of Cardiac and Thoracic Vascular Surgery, University Hospital Luebeck, Ratzeburger Allee 160, Luebeck, Germany. Tel: ; fax: ; stefan.klotz@uksh.de (S. Klotz). Received 11 September 2014; received in revised form 29 January 2015; accepted 3 February 2015 Abstract OBJECTIVES: Acute aortic dissection type A (AADA) is still an emergency operation with high morbidity and mortality. In this acute situation quick to the heart lung machine and systemic cooling is often life-saving. However, the often easy access to the femoral vessels for leads to an arterial backflow in the descending aorta with the likelihood of plaque rupture and cerebral embolism. We analysed the outcome after initial femoral versus central for AADA. METHODS: All patients with acute aortic dissection type A operated between January 2003 and December 2012 were evaluated for the type of arterial (femoral vs central) for initial bypass. Demographic data and outcome parameters were accessed. No patient was excluded. RESULTS: One hundred and seventy-seven patients were operated on with acute type A dissection in the last 10 years; 94 (53.1%) were initially cannulated in the central aortic vessels and 83 (46.9%) in the femoral artery. The patients were comparable with regard to age (61.1 ± 14.9 vs 62.2 ± 15.0 years, P = 0.607), gender (male, 62 vs 69%, P = 0.348), EuroSCORE (11.5 ± 4.0 vs 12.8 ± 4.3, P = 0.057) and previous sternotomy (17% in both groups). Bypass (243 ± 105 vs 233 ± 83 min, P = 0.471), cross-clamp (160 ± 86 vs 150 ± 66 min, P = 0.381) and circulatory arrest times (47.8 ± 24.7 vs 42.5 ± 21.7 min, P = 0.130) were similar as were lowest temperatures (17.7 ± 1.8 vs 17.6 ± 1.3, P = 0.652). Postoperative cerebral infarction and 30-day mortality were comparable between the groups (13 vs 9%, P = and 20 vs 17%, P = 0.699, central vs peripheral ). Only postoperative need for dialysis was borderline significantly higher in the femoral group (28 vs 40%, P = 0.073). CONCLUSIONS: This single-centre study with 177 patients could show that an acute aortic dissection type A can be operated on with central and peripheral with similar results. Risk for early mortality was driven by the preoperative clinical and haemodynamic status before operation rather than the technique. Keywords: Type A dissection Cannulation Outcome INTRODUCTION Acute aortic dissection type A (AADA) remains a life-threatening medical condition requiring emergency surgical therapy with a high mortality and morbidity [1, 2]. The use of extracorporeal circulation with hypothermic circulatory arrest is still the gold standard and only therapeutic option [3]. Without operation outcome is unacceptable [4]. The standard approach to AADA is median sternotomy and replacement of the ascending aorta with resection of the entry site with an open distal ascending aortic or hemiarch replacement, depending on the intimal tears. The open distal anastomosis needs a period of hypothermic circulatory arrest often with the use of neuroprotective strategies Presented at the 28th Annual Meeting of the European Association for Cardio- Thoracic Surgery, Milan, Italy, October like selective cerebral perfusion [5]. Extracorporeal circulation is needed for this approach and the techniques might influence the outcome of the patients. Central in the ascending aorta has the advantage of antegrade body perfusion but the risk of cannulating the false lumen. False lumen might lead to progression of the dissection, malperfusion or aortic rupture. In many studies of the subclavian artery either directly or with an end-to-side prosthesis is the first option in AADA. This is often termed as central, despite a short retrograde flow in this vessel. Retrograde perfusion via the femoral artery offers an easy and fast accessible site, but leads to retrograde flow in the descending and ascending aorta and might have an impact on plaque rupture and cerebral embolism. While some studies show a positive effect with central [6], other studies could not demonstrate any benefit [7, 8]. ORIGINAL ARTICLE The Author Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

2 750 S. Klotz et al. / Interactive CardioVascular and Thoracic Surgery We analysed a single-centre series of AADA with different techniques for initial bypass for characteristic outcome parameters. METHODS Study design Patients with diagnosed AADA were divided into two groups by the modality of initial arterial for extracorporeal circulation: either central through the ascending aorta, right subclavian/axillary artery or right carotid artery (central group) or peripheral through the right or left femoral artery. No patient was excluded from the study. AADA was defined as diagnosed within less than 24 h before operation. All patients were directly transferred into the operation theatre after diagnosis. The institutional review board approved this retrospective analysis; additional patient consent was not required. Surgical technique A median sternotomy was performed in all patients. Aortic was performed after sternotomy. Subclavian/axillary, carotid or femoral was performed either before sternotomy or thereafter, depending on the clinical status of the patient. Aortic was performed after heparinization by the Seldinger technique guided by transoesophageal echocardiography. If the Seldinger wirewasinthetruelumenoftheaorta,aringreinforcedaortic cannula was inserted (OptiSite, Edward Lifesciences Corporation, Irvine, CA, USA or EOPA, Medtronic, Minneapolis, MN, USA) and fixed with tourniquets. Subclavian/axillary or carotid was performed through an extra incision above the vessel and prior implantation of an 8 mm Dacron graft onto the vessel after heparinization. Femoral was performed with an open approach and direct (Fem-Flex, Edward Lifesciences Corporation, Irvine, CA, USA). The criteria in selection of the site depended on the experience of the surgeon in combination with the experience of the anaesthesiologist in performing transoesophageal echocardiography, the haemodynamic state of the patients and the extent of the dissection. Body temperature was monitored with bladder or rectal in addition with oesophageal temperature measurement. Cerebral perfusion was either unilateral or bilateral depending on the oxygen consumption in the brain diagnosed by near-infrared spectrography, which was routinely performed in all patients. Retrograde cerebral perfusion was not routinely performed and only used for deairing. The ascending aorta was replaced with a woven Dacron graft, which was curved if the hemiarch or arch was involved, too. If the aortic valve was involved, root replacement was made either with a Bentall-de Bono procedure or a valve-sparing repair according to David or Yacoub. Statistical methods All data were sampled retrospectively from the clinical data sheets. A χ 2 test was used to compare categorical variables; a Student t-test was used to compare continuous variables. A P-value of <0.05 was considered statistically significant. For mortality risk factor distribution a univariate analysis was performed. All significant parameters from the univariate analysis were included in a multivariate logistic regression. IBM SPSS Statistics Version 20 (IBM Germany, Ehningen) was used for all analysis. RESULTS A total of 177 consecutive patients were diagnosed with AADA (Stanford Type A or DeBakey Type I, n = 156 and DeBakey Type II, n = 21) by contrast-enhanced computer tomography or echocardiography and underwent emergency ascending aortic surgery from January 2003 until December Patient characteristics are presented in Table 1. There were no significant differences in age, gender, body-mass index (BMI), European System for Cardiac Operative Risk Evaluation (EuroSCORE) I, cardiac reoperation, preoperative neurologic disease or neurologic state, diabetes, shock state, preoperative creatinine and need for cardiopulmonary resuscitation between the central and peripheral groups. In addition, the proportion of patients with low ejection fraction, and preoperative intubation and inotrope dependence was similar. However, the ASA (American Society of Anesthesiologist) Physical Status Classification System (3.5 ± 0.74 vs 3.7 vs 0.59, P =0.008)was significantly higher in the peripheral group. Central was performed in 94 patients (53.1%), while peripheral through the right or left femoral artery was performed in 83 patients (46.9%). Venous drainage was performed either through the femoral vein (n = 19, 10.7%) or a double-stage cannula in the right atrium (n = 156, 88.1%). Bicaval venous was performed in 2 patients (1.1%). After starting extracorporeal circulation, the body temperature was cooled to 18 C in all patients (17.7 ± 1.6). During hypothermic circulatory arrest direct cerebral perfusion was used in 55.3% with central and in 45.8% with femoral. Concomitant cardiac procedures were coronary artery bypass grafting in 10.2% (n = 18), mitral valve reconstruction in 0.6% (n = 1) and persistent foramen ovale closure in 0.6% (n = 1). An additional procedure on the aortic valve was performed in 75 (42.6%) cases: Bentall-de Bono procedure in 23.4% (n = 41), valve replacement in 1.7% (n = 3) and valve-sparing repair in 17.7% (n = 31). A list of all surgical procedures is presented in Table 2. Regarding the intraoperative data, operation, bypass and X-clamp times were similar in both groups. In addition, the time of circulatory arrest and the lowest patient temperature were comparable. Additional cardiac procedures (valve replacement/reconstruction, coronary artery bypass grafting, hemi- or full arch replacement) were similar between the groups except for implantation of an elephant trunk during full arch replacement, which was performed in 1 patient (1.2%) in the peripheral group and 10 patients (10.6%) in the central group (P = 0.011). Table 3 presents the outcome data. The 30-day mortality and intensive care unit (ICU) stay were similar as was the use of the intra-aortic balloon pump and extracorporeal membrane oxygenation (ECMO) postoperatively. The overall hospital mortality rate was 25.5% (24 patients) in the central and 19.3% (16 patients) in the peripheral group (P = 0.370). The mean hospital length of stay was 17.1 ± 19.9 days in the central and 17.6 ± 13.4 days in the peripheral group (P = 0.859). The length of stay in the intensive care unit was

3 S. Klotz et al. / Interactive CardioVascular and Thoracic Surgery 751 Table 1: Patient characteristics (mean ± SD) Variable All patients Central Peripheral P-values n (53%) 83 (47%) Age (years) 61.6 ± ± ± Sex, male 115 (65%) 58 (62%) 57 (69%) BMI (kg/m 2 ) 26.8 ± ± ± EuroSCORE I 12.1 ± ± ± Previous sternotomy 30 (17%) 16 (17%) 14 (17%) Previous neurologic disease 13 (7%) 4 (4%) 9 (11%) Preoperative creatinine (mmol/l) 107 ± ± ± Diabetes 14 (8%) 7 (8%) 7 (9%) Shock state 40 (23%) 21 (23%) 19 (23%) Previous cardiopulmonary reanimation (CPR) 4 (2%) 1 (1%) 3 (4%) (<48 h before operation) ASA classification 3.5 ± ± ± EF, <50% 37 (24%) 19 (24%) 18 (24%) Preoperative intubation 16 (9%) 8 (9%) 8 (10%) Preoperative inotropes 29 (16%) 14 (15%) 15 (18%) BMI: body mass index; EF: ejection fraction. Table 2: Intraoperative characteristics and additional cardiac procedures Variable All patients Central Peripheral P-values DeBakey Type I 156 (88%) 86 (92%) 70 (84%) Operation time (min) 417 ± ± ± Bypass time (min) 238 ± ± ± Cross-clamp time (min) 155 ± ± ± Circulatory arrest time (min) 45.3 ± ± ± Lowest temperature ( C) 17.7 ± ± ± Antegrade selective cerebral perfusion 90 (51%) 52 (55%) 38 (46%) Time of cerebral perfusion (min) 38.3 ± ± ± Bentall-de Bono 14 (8%) 6 (6%) 8 (10%) AKR (David) 19 (11%) 11 (12%) 8 (10%) AKR (Yacoub) 13 (7%) 7 (7%) 6 (7%) Additional hemiarch replacement 99 (56%) 56 (60%) 43 (52%) Additional full arch replacement 10 (6%) 8 (9%) 2 (2%) Additional elephant trunk 11 (6%) 10 (11%) 1 (1%) Additional CABG 18 (10%) 11 (12%) 7 (8%) Additional mitral valve replacement 1 (1%) 1 (1%) 0 (0%) AKR: aortic valve/root reconstruction; CABG: coronary artery bypass grafting. 9.3 ± 9.4 days in the central and 10.3 ± 10.5 days in the peripheral group (P = 0.538). A new cerebral event or cerebral infarction on computer tomography (CT) scan was identical in both groups. The Rankin scale of the patients with cerebral infarction was comparable between the groups. In addition, the development of a postoperative psycho-syndrome was similar and was observed in almost one-third of all patients after deep hypothermic cardiac arrest. Additional complications, like need for a rethoracotomy was comparable between both groups. Of the 11 patients with rethoracotomy in the femoral group, 9 (81.8%) were due to increased blood loss and 2 (18.2%) due the haemodynamic effects of tamponade. Of the 9 patients in the central group, 5 (55.6%) were due to increased blood loss and 4 (44.4%) due to tamponade. The amount of blood transfusion was 6.3 ± 7.2 and 7.8 ± 11.5 (P = 0.315) in the central and peripheral groups; 26 (27.7%) patients of the central group and 16 (19.3%) of the peripheral group received no blood during their hospital stay. The fresh frozen plasma transfusion was 4.0 ± 5.4 and 5.6 ± 8.7 (P = 0.142); 44 (46.8%) patients of the central group and 31 (37.3%) of the peripheral group received no fresh frozen plasma during their hospital stay. Postoperative renal failure with the need for dialysis was borderline significantly higher in the femoral artery group (40.2 vs 28.3%, P = 0.07). A sternal infection with a need for operative therapy was noted in 4 patients (4.3%) in the central and in 3 patients (3.6%) in the femoral group (P = 1.000). Reintubation was needed in 23.9% (22 patients) in the central and 25.9% (21 patients) in the peripheral ORIGINAL ARTICLE

4 752 S. Klotz et al. / Interactive CardioVascular and Thoracic Surgery Table 3: Variable Outcome parameters All patients Central Peripheral P-values 30-day mortality 33 (19%) 19 (20%) 14 (17%) ICU stay (days) 9.8 ± ± ± IABP 4 (2%) 2 (2%) 2 (3%) ECMO 5 (3%) 3 (3%) 2 (3%) New cerebral 17 (11%) 11 (13%) 6 (9%) event Rankin scale 3.5 ± ± ± Psycho-syndrome 57 (33%) 29 (32%) 28 (34%) Rethoracotomy 20 (13%) 9 (11%) 11 (16%) Dialysis on ICU 57 (33%) 25 (28%) 32 (40%) Days on dialysis 3.0 ± ± ± Creatinine (mmol/l) 130 ± ± ± ICU: intensive care unit; IABP: intra-aortic balloon pump; ECMO: extracorporeal membrane oxygenation. Table 4: Variables for 30-day mortality Variable Death Survival P-values n 33 (19%) 144 (81%) Age (years) 70.6 ± ± EuroSCORE I 16.0 ± ± Shock state 13 (39%) 27 (19%) CPR 3 (9%) 1 (1%) Preoperative intubated 8 (24%) 8 (6%) Preoperative inotropes 12 (36%) 17 (12%) ASA Classification 3.9 ± ± EF, <50% 12 (41%) 24 (19%) ECMO 4 (14%) 1 (1%) CPR: cardiopulmonary reanimation; EF: ejection fraction; ECMO: extracorporeal membrane oxygenation. group (P = 0.860). A tracheotomy was performed in 16.3% (15 patients) in the central and in 16.0% (13 patients) in the peripheral group (P = 1.000). In an additional analysis, Table 4 gives the variables with significant impact on 30-day mortality. Only the variables with significance are plotted. Patients with a risk of dying in the early postoperative phase are significantly older and with a higher EuroSCORE I and ASA classification. In addition, patients with a preoperative shock state or need for cardiopulmonary reanimation, or inotrope-dependent and intubated patients have a higher risk of dying. However, in the multivariate analysis only postoperative need for ECMO support and EuroSCORE I were significant risk factors for 30-day mortality in our patients (Table 5). The choice of initial had no impact on the 10-year long-term outcome, as depicted in Fig. 1. octogenarians [2]. In our single-centre study we report a 30-day mortality rate of 19% in 177 patients, which is confirmed by a multi-centre study with 2137 patients. In addition, postoperative neurological symptoms were presented in 12 15% of the patients [4]. Our data showed a new neurologic event in 11% of all patients with no differences if femoral or central was used. In a meta-analysis of 9 AADA studies Ren et al.[8] could show a significant lower short-term mortality and postoperative neurological benefit in patients with axillary in contrast to femoral artery. As a limitation of this study, it is not known whether selective cerebral perfusion was performed during circulatory arrest and which was the lowest body temperature. In our study, we used a deep circulatory arrest with an average temperature of 17.7 C and additional selective antegrade cerebral perfusion in 51% of all patients. The time of cerebral perfusion was on average 84.5% of the time of circulatory arrest with no differences between both perfusion groups. However, the use of additional selective cerebral perfusion had no postoperative neurological impact in our study at an average temperature <18 C. Our data show that femoral was performed more often in a somewhat sicker patient group measured by the ASA classification. In addition, the EuroSCORE I tended to be higher in the femoral group. The reason for this might be a faster access to the site compared with access to the subclavian artery. Some contemporary studies suggest better outcome with central [7, 9, 10]. In the study by Etz et al. the group with femoral artery showed significantly shorter operation and circulatory arrest times. However, outcome parameters, especially postoperative stroke (18 vs 15%) and early death (21 vs 20%, peripheral vs central ) were comparable. Only late mortality was higher in the femoral group [7]. In the meta-analysis by Tiwari et al. [10] axillary artery was superior regarding overall outcome compared with central. In addition, the study by Kamiya et al. [9] could only show a slight benefit with aortic compared with femoral regarding 30-day mortality, despite higher ASA classification in the femoral group. In addition, EuroSCORE I, preoperative neurologic disease and creatinine were slightly better in the femoral group. In our study, we could not find any differences in neurologic symptoms regarding the perfusion strategy. Similar to the multicentre study by Rylski et al. [2], age was not a predictor for worse neurologic outcome. The only borderline significant difference in outcome parameters was the need for dialysis in the ICU with 40% in the femoral artery group compared with 28% in the central group (P = 0.073). Univariate and multivariate logistic regression analyses were performed to characterize risk factors for 30-day mortality. In contrast to postoperative neurological symptoms, age was a significant factor for worse 30-day mortality as was worse clinical appearance before the operation (EuroSCORE I, shock, reanimation, intubation and inotropic support) (Table 4). In addition, only one patient with postoperative ECMO support after operation of AADA survived. In the multivariate analysis, postoperative ECMO and preoperative EuroSCORE I > 13 were significant independent risk factors for 30-day mortality in AADA patients. DISCUSSION Mortality with AADA remains high with an average 30-day mortality rate of 17.1%, which progressively increases to 25% in LIMITATIONS This study has some limitations, which needed to be addressed. First, this is a retrospective data analysis in a very heterogeneous

5 S. Klotz et al. / Interactive CardioVascular and Thoracic Surgery 753 Table 5: Independent risk factors for 30-day mortality Variable Univariate Multivariate OR 95% CI P-values OR 95% CI P-values ECMO CPR EuroSCORE I Preoperative intubated Preoperative inotropes Age ASA classification EF, <50% Shock state ECMO: extracorporeal membrane oxygenation; CPR: cardiopulmonary reanimation; EF: ejection fraction. The bold values as marked of the significant parameters in the multivariate analysis. Figure 1: Kaplan Meier curve of the long-term survival in the central and peripheral groups with the corresponding reasons of death. patient population. In addition, the choice of cannulating a central or peripheral vessel was mainly driven by the experience of the surgeon rather than objective parameters. CONCLUSION Our single-centre study with 177 patients operated on for acute Type A dissection revealed that the technique (femoral or central vessels) did not have any impact on postoperative neurology, 30-day mortaliy or any other postoperative outcome parameter. This might be influenced by the constant use of circulatory arrest in a profound hypothermic state with a body temperature <18 C. However, this low temperature did not affect the average operation time or the need for rethoracotomy for bleeding compared with the studies in the literature. The risk of dying within 30 days after the operation depended on the haemodynamic state and the overall clinical status measured by the EuroSCORE I of the patients at the time of presentation in the operation theatre. Higher age was a risk factor for mortality but not postoperative neurological symptoms. We conclude that femoral artery is a safe and easy-access technique with similar outcome in AADA patients and should be used especially in haemodynamically unstable patients. Conflict of interest: none declared. REFERENCES [1] Rylski B, Suedkamp M, Beyersdorf F, Nitsch B, Hoffmann I, Blettner M et al. Outcome after surgery for acute aortic dissection type A in patients over 70 years: data analysis from the German Registry for Acute Aortic Dissection Type A (GERAADA). Eur J Cardiothorac Surg 2011;40: [2] Rylski B, Hoffmann I, Beyersdorf F, Suedkamp M, Siepe M, Nitsch B et al. Acute aortic dissection type A: age-related management and outcomes reported in the German Registry for Acute Aortic Dissection Type A (GERAADA) of over 2000 patients. Ann Surg 2014;259: [3] Kruger T, Conzelmann LO, Bonser RS, Borger MA, Czerny M, Wildhirt S et al. Acute aortic dissection type A. Br J Surg 2012;99: [4] Matsui M, Toshikazu G, Yahagi T, Tamada Y, Fukui A, Takahashi K et al. [Prognosis of type A acute aortic dissection treated conservatively]. Kyobu Geka 2010;63: [5] Easo J, Weigang E, Holzl PP, Horst M, Hoffmann I, Blettner M et al. Influence of operative strategy for the aortic arch in DeBakey type I aortic dissection - analysis of the German Registry for Acute Aortic Dissection type A (GERAADA). Ann Cardiothorac Surg 2013;2: [6] Schurr UP, Emmert MY, Berdajs D, Reuthebuch O, Seifert B, Dzemali O et al. Subclavian artery provides superior outcomes in patients with acute type-a dissection: long-term results of 290 consecutive patients. Swiss Med Wkly 2013;143:w [7] Etz CD, von Aspern K, da Rocha E, Silva J, Girrbach FF, Leontyev S et al. Impact of perfusion strategy on outcome after repair for acute type a aortic dissection. Ann Thorac Surg 2014;97: [8] Ren Z, Wang Z, Hu R, Wu H, Deng H, Zhou Z et al. Which (axillary or femoral ) is better for acute type A aortic dissection repair? A meta-analysis of nine clinical studies. Eur J Cardiothorac Surg 2015;47: [9] Kamiya H, Kallenbach K, Halmer D, Ozsöz M, Ilg K, Lichtenberg A et al. Comparison of ascending aorta versus femoral artery for acute aortic dissection type A. Circulation 2009;120:S [10] Tiwari KK, Murzi M, Bevilacqua S, Glauber M. Which (ascending aortic or peripheral arterial ) is better for acute type A aortic dissection surgery? Interact CardioVasc Thorac Surg 2010;10: ORIGINAL ARTICLE

6 754 S. Klotz et al. / Interactive CardioVascular and Thoracic Surgery APPENDIX. CONFERENCE DISCUSSION Scan to your mobile or go to to search for the presentation on the EACTS library Dr B. Rylski (Freiburg, Germany): Please could you explain what your criteria is for ascending versus femoral? When you cannulate dissected ascending aorta, there is a risk of false lumen. After opening of the aortic arch, you can easily assess whether the aortic cannula is positioned in the true or in the false lumen. Could you tell us in how many patients did you cannulate the false lumen? Most surgeons do not use this access considering the risk of aortic rupture, false lumen, or embolization risk. Did you observe any of these complications in this big series of patients? Dr Klotz: Yes, great questions. Regarding the second question, it s correct. I will not say aortic is dangerous. We saw it, at least what I know, twice in patients with resuscitation in the operation room. We just did the sternotomy and the aortic with an anaesthesiologist in the night which was not so confirmed to see a guidewire in the TOE. Both patients had false lumen s and false lumen perfusion. One patient died in the operation room and the other patient we just clamped the aorta, pull the cannula out, put all the venous blood in the drainage, and opened the aorta and did a directly in the aortic arch and started perfusion again. For the first question, we don t have absolute rules. It s depending on the surgeon, on the status of the patient and on the anaesthesiologist on call during the night. Type A dissections are mostly in the night. The standard approach is subclavian artery; however, if the patient is obese or haemodynamically unstable, we just go for the femoral artery. So with this data presented here, we could show that our results with femoral artery are not worse than the subclavian artery, so we just go to the femoral arteries. It s an easily accessible site, and we don t have any pain trying to find the subclavian artery and then doing a side branch or just direct of the subclavian artery because you just go to the femoral artery. Dr M. Grabenwöger (Vienna, Austria): Maybe you see no difference because you cooled down all patients below 20 C. I think the advantage of the subclavian artery is when you are operating in moderate hypothermia with antegrade perfusion and then maybe you can find the difference. If you cool down to 18 C, I m with you, maybe there is no difference. Dr Klotz: This is the only guideline in Lübeck, below 18 C. It never changed so far. Dr Grabenwöger: Yes, but you should not stick till the end of your life to something which could be improved. Dr Klotz: That s correct. Dr Grabenwöger: It s easier for the surgeons. It s easier for the patient. It s easier for everybody I think not to cool down too far. Dr Klotz: Yes. Dr C. Hagl (Munich, Germany): Is it correct when I speculate that your dialysis rate of 30% may be due to prolonged cardiopulmonary bypass time including prolonged cooling and rewarming? Dr Klotz: We see it in the operation time; it takes a little bit longer. Dr Hagl: Quite much longer. Your technique is comparable to the Mount Sinai technique of deep hypothermia. Dr Klotz: These are the guidelines we have, it s difficult to change. ecomment. Perfusion strategies in type A acute aortic dissection Author: Roberto Gaeta Cardiac Surgery, University of Messina, Messina, Italy doi: /icvts/ivv088 The Author Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This interesting paper raises many questions that could not be answered only by experience of the surgeon and of the anaesthesiologist [1]. It does not describe the modality of selective antegrade cerebral perfusion (SACP), and in particular, the pressures and ph strategies during SACP. This is a very important issue as we know that some degree of auto-regulation is lost at temperatures (<18 C) as low as that used by these Authors. This phenomenon may increase the cerebral vessel pressure and potentially cause excess perfusion and neurological damage by overflow [2]. During hypothermic circulatory arrest, direct cerebral perfusion was used in 55.3% with central and in 45.8% with femoral. We do not know the reasons for this choice in the non-sacp-perfused group. Regardless of the arterial inflow method, we believe, as do many other Authors, that if a supra-aortic vessel is not to be perfused during SACP, it should be clamped to prevent steal and subsequent neurological injury [2]. This technical aspect has not been described in this paper. There is no mention of the occurrence of visceral malperfusion, which is a major complication in these patients [3, 4]. The site of may not only affect neurological outcome but may also cause malperfusion of visceral arteries and retrograde emboli to the kidneys [3]. This event, along with a longer bypass time could be the cause of the borderline significant difference in the need for dialysis in the ICU with 40% in the femoral artery group compared with 28% in the central group (P = 0.073). The dialysis figures are quite high. Another very important issue is the evolving pattern during extracorporeal circulation. It is mandatory to keep checking the blood flow status both by transoesophageal echocardiography (TOE) [5] and by near infrared spectrography (NIRS). This has to be done also at the end of repair in order to diagnose any residual false lumen. All these tips could help in decreasing complications during surgery of AADA and achieve clear conclusions about the choice of site. Conflict of interest: none declared. References [1] Klotz S, Heuermann K, Hanke T, Petersen M, Sievers HS. Outcome with peripheral versus central in acute Type A dissection. Interact CardioVasc Thoracic Surg 2015;20: [2] Griepp RB, Griepp EB. Perfusion and strategies for neurological protection in aortic arch surgery. Ann Cardiothorac Surg 2013;2: [3] Oderich GS, Panneton J. Acute aortic dissection with side branch vessel occlusion: surgical options. Semin Vasc Surg 2002;15: [4] Lentini S, Savasta M, Ciuffreda F, La Monaca M, Gaeta R. Treatment of malperfusion during surgery for type A aortic dissection. J Extra Corpor Technol 2009;41: [5] Coletti G, Torracca L, La Canna G, Maisano F, Sebastiano P, Fucci C et al. Diagnosis and management of cerebral malperfusion phenomena during aortic dissection repair by transesophageal Doppler echocardiographic monitoring. J Card Surg 1996;11:355 8.