ORIGINAL ARTICLE. Abstract INTRODUCTION

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1 European Journal of Cardio-Thoracic Surgery 52 (2017) doi: /ejcts/ezx189 Advance Access publication 22 June 2017 ORIGINAL ARTICLE Cite this article as: Takeda K, Garan AR, Ando M, Han J, Topkara VK, Kurlansky P et al. Minimally invasive CentriMag ventricular assist device support integrated with extracorporeal membrane oxygenation in cardiogenic shock patients: a comparison with conventional CentriMag biventricular support configuration. Eur J Cardiothorac Surg 2017;52: Minimally invasive CentriMag ventricular assist device support integrated with extracorporeal membrane oxygenation in cardiogenic shock patients: a comparison with conventional CentriMag biventricular support configuration Koji Takeda a, *, Arthur R. Garan b, Masahiko Ando a,jihohan a,velik.topkara b,paulkurlansky a, Melana Yuzefpolskaya b, Maryjane A. Farr b, Paolo C. Colombo b, Yoshifumi Naka a and Hiroo Takayama a a b Division of Cardiothoracic Surgery, Department of Surgery, Columbia University Medical Center, New York, NY, USA Division of Cardiology, Department of Medicine, Columbia University Medical Center, New York, NY, USA * Corresponding author. Division of Cardiothoracic Surgery, Department of Surgery, Columbia University Medical Center, 177 Fort Washington Avenue, New York, NY 10032, USA. Tel: ; fax: ; kt2485@cumc.columbia.edu (K. Takeda). Received 26 January 2017; received in revised form 8 May 2017; accepted 10 May 2017 Abstract OBJECTIVES: We recently developed a novel minimally invasive surgical approach that combines extracorporeal membrane oxygenation and CentriMag ventricular assist device (Ec-VAD) for the treatment of cardiogenic shock as a short-term circulatory support. We compared the outcomes of this new approach to conventional CentriMag biventricular assist device (BiVAD) support through a median sternotomy. METHODS: Between July 2015 and August 2016, 22 patients were implanted with CentriMag Ec-VAD and 90 patients were implanted with conventional CentriMag BiVAD. The Ec-VAD circuit was configured with left ventricular apical cannulation via a mini-thoracotomy and femoral venous cannulation as inflows and right axillary artery cannulation as an outflow. RESULTS: Patients with Ec-VAD were older (58 ± 9.9 vs 53 ± 13 years, P = 0.06), had more preoperative percutaneous mechanical circulatory support use (82% vs 44%, P < 0.01) and less cardiopulmonary bypass use intraoperatively (0% vs 66%, P < 0.01). Patients who received Ec-VAD required less transfusions. The Ec-VAD group had a significantly lower incidence of major bleeding events during support (32% vs 72%, P < 0.01). Average systemic flow was similar (Ec-VAD: 5.5 ± 0.94 vs BiVAD: 5.7 ± 1.1 l/min, P = 0.4). Seventeen patients (77%) with Ec- VAD survived to the next destination compared with 66 patients (73%) with BiVAD (P = 0.45). Thirty-day survival was similar between groups (Ec-VAD 86% vs BiVAD 76%, P = 0.39), and overall 1-year survival was 61% in Ec-VAD and 55% in BiVAD (P = 0.7). CONCLUSIONS: Ec-VAD is a unique approach for the treatment of patients in cardiogenic shock. It eliminates the need for cardiopulmonary bypass and reduces blood product utilization and bleeding events. Keywords: Ventricular assist device Cardiogenic shock Minimally invasive Extracorporeal membrane oxygenation INTRODUCTION Short-term mechanical circulatory support (ST-MCS) has been increasingly used in acute haemodynamic decompensation and refractory cardiogenic shock [1, 2]. Various types of percutaneous ST-MCS have been developed, and clinical outcomes continue to improve with new technologies [1, 2]. However, percutaneous ST-MCS require special skills for insertion and are limited in power, durability and patient mobility after implantation [2]. Although temporary external ventricular assist device (VAD) using CentriMag pump (St Jude Medical Inc., St Paul, MN, USA) has the advantage of providing sufficient biventricular support and durability, the standard technique requires median sternotomy and the use of cardiopulmonary bypass [3]. To overcome these disadvantages, we recently developed a novel minimally invasive CentriMag VAD insertion technique combined with extracorporeal membrane oxygenation (ECMO) [4]. This technique allows us to provide biventricular unloading without sternotomy and cardiopulmonary bypass in cardiogenic shock patients who often accompany some degree of biventricular dysfunction. The purpose of this study is to compare the outcomes of this new approach (Ec-VAD) with conventional CentriMag biventricular VAD (BiVAD) through median sternotomy. VC The Author Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

2 1056 K. Takeda et al. / European Journal of Cardio-Thoracic Surgery METHODS Our institutional review board approved this study with waiver of consent. We retrospectively reviewed our experiences in surgical implantation of external CentriMag VAD at Columbia University Medical Center between January 2007 and September During this period, 267 consecutive patients with various aetiologies of cardiogenic shock underwent CentriMag VAD placement as a bridge to decision therapy. Of these, 162 patients underwent CentriMag BiVAD placement from January 2007 to June Since July 2015, 22 patients underwent Ec-VAD as a standard approach. Seventy-two patients who had BiVAD for postcardiotomy shock and post-transplant graft failure were excluded from this study, because we currently do not insert Ec-VAD in these patients who recently underwent median sternotomy as one of the benefits of Ec-VAD is sparing sternum for future surgery. A total of 90 patients with conventional BiVAD and 22 patients with Ec-VAD were included in this study. Indications and surgical technique All patients underwent external CentriMag VAD insertion as a bridge to decision therapy. Our algorithm for bridge to decision for cardiogenic shock has been previously described [3]. A patient with cardiogenic shock is characterized by (i) systolic blood pressure of <90 mmhg, (ii) cardiac index <2.0 l/min/m 2, (iii) pulmonary capillary wedge pressure >16 mmhg (or evidence of pulmonary oedema in the absence of a pulmonary artery catheter) and (iv) evidence of end-organ failure. These patients are rapidly evaluated by our multidisciplinary Shock Team consisting of cardiac surgeons, interventional and heart failure cardiologists, nurse practitioners and intensive care physicians to determine the most suitable ST-MCS device in each patient. Conventional BiVAD was the primary mode of support from January 2007 to June 2015 and its implantation technique has previously been reported [3]. After standard sternotomy with cardiopulmonary bypass, the inflow cannula (28 40 Fr) is inserted into the left atrium or left ventricular apex for the left VAD. An 8-mm or a 10-mm Dacron graft is sewn onto the ascending aorta. The outflow cannula (18 24 Fr) is inserted through the graft and secured with silk ties. For the right VAD, the inflow cannula (28 31 Fr) is inserted into the right atrium, and the outflow cannula (18 24 Fr) is inserted into the main pulmonary artery. The Ec-VAD is currently our standard approach since July 2015 for all types of cardiogenic shock, except for patients who had recent open-heart surgery, because these patients already have an open chest. Ec-VAD is implanted without cardiopulmonary bypass and the technique was previously reported in detail [4]. An 8-mm or a 10-mm Dacron graft is sewn onto the right axillary artery, and the arterial cannula (18 24 Fr) is inserted into the graft. Through a small left thoracotomy, double mattress sutures buttressed with pericardial pledgets are placed at the apex and an inflow cannula (28 32 Fr) is inserted into the left ventricle through a stab wound. Femoral venous cannulation using 21 or 23 Fr Bio-Medicus cannula (Medtronic Inc., Minneapolis, MN, USA) is added as an additional inflow to unload the right ventricle. Apical and venous cannulas are connected with a Y-connector, and an oxygenator (Quadrox D, Maquet Inc., Wayne, NJ, USA) is spliced into the circuit (Fig. 1A). In patients with preoperative femoral veno-arterial ECMO, existing femoral venous cannula can be utilized as an inflow. The blood flow through each inflow and outflow limb is monitored with a transonic flow sensor. Tube constrictor was used to adjust the flow ratio of 2 inflow limbs (apical and venous). If the difference in mean radial arterial pressure of the perfused side is greater than 20 mmhg compared to the other side, axillary artery banding distal to the cannulation site is added to prevent hyperperfusion. Post-implant device management Anticoagulation with intravenous heparin was initiated at a rate of 300 U/h once the chest tube drainage became serosanguinous. A partial thromboplastin time was measured every 8 h. Heparin dose was gradually titrated and maintained throughout support with a goal of s. Once the overall condition of the patient begins to improve based on acceptable haemodynamics, clearance of lactate, improvement in end-organ function if injury has occurred and a stable neurological condition and myocardial function is then challenged by device weaning. The weaning study is generally performed in the intensive care unit under monitoring with a Swan-Ganz catheter and echocardiography guidance. Based on the weaning test results, the device is explanted to one of the following destinations: exchange to durable left VAD, explantation if there is sufficient myocardial recovery or explantation for heart transplantation. Our BiVAD weaning protocol was reported previously [3]. First, the right VAD is weaned to 1 l/min under central venous pressure monitoring. Acceptable right ventricular function includes maintenance of central venous pressure <13 mmhg, stable mean arterial pressure (>60 mmhg) and stable left VAD flow. If the patient tolerated right VAD weaning, the left VAD is weaned to 3 l/min. If haemodynamics remains stable, a bolus of heparin ( IU) is given, and the VAD flows are further reduced to 1 l/min. In patients with Ec-VAD, once vasoactive medication requirement is minimal, attention is then turned towards removal of the femoral venous limb. The venous limb flow is gradually weaned to 1.5 l/min under central venous pressure monitoring. If the above parameters for right VAD are met, the venous limb is temporarily clamped at the bedside as a final test to reassess the parameters. Once the venous cannula is removed, we quickly wean the fraction of inspired oxygen of the oxygenator to 40%. The oxygenator is removed if the partial pressure of arterial oxygen in blood gas sampling is greater than 100 mmhg on minimal ventilator settings. Then the patient can ambulate with apico-axillary left VAD (Fig. 1B). The left VAD is weaned with the same method as BiVAD. If the patient cannot tolerate femoral venous weaning, venous limb is switched to jugular vein for patient mobility. Data collection and follow-up Preoperative variables included age; gender; aetiology of heart failure; the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) score; comorbidities including diabetes, hypertension and prior percutaneous support; and labs for anaemia, thrombocytopaenia, coagulopathy and end-organ function (Table 1). Intraoperative variables included use of cardiopulmonary bypass, type and amount of blood products and types and number of arterial and venous cannulas (Table 2). Postoperative data included complications during support, incidence of major bleeding and stroke and outcomes including recovery, transition to durable support, transplantation and death

3 K. Takeda et al. / European Journal of Cardio-Thoracic Surgery 1057 Figure 1: (A) Schematic diagram of extracorporeal ventricular assist device (Ec-VAD) and (B) conversion to apico-axillary left ventricular assist device. including cause of death (Table 3). Follow-up was completed on 30 September 2016 and completed in 100% of patients. Statistical analysis Stata (Stata Corp, College Station, TX, USA) software was used for statistical analysis. Data are expressed as frequencies and percentages for categorical variables. Continuous variables are expressed as mean ± standard deviation and were compared using 2-sample t-tests. Categorical variables were compared using v 2 test. Kaplan Meier curves were created to represent survival and were compared using a log-rank test. For all analyses, P-values <0.05 were considered statistically significant. RESULTS Baseline characteristics at the time of device insertion Baseline data and comparisons between BiVAD and Ec-VAD groups are summarized in Table 1. Patients in the BiVAD group were more likely to be younger, more frequently supported by intra-aortic balloon pump and less frequently supported by percutaneous ST-MCS such as femoral veno-arterial ECMO and Impella (Abiomed, Inc., Danvers, MA, USA). Regarding preoperative laboratory values, patients in the BiVAD group had a significantly higher preoperative platelet count compared with those in the Ec-VAD group. Intraoperative variables Table 2 summarizes the intraoperative outcomes. Fifty-nine (66%) of BiVAD patients required cardiopulmonary bypass with a mean bypass time of 85 ± 45 min. Patients with Ec-VAD did not require cardiopulmonary bypass. Implantation of BiVAD required significantly more packed red blood cell, fresh frozen plasma and platelet transfusions. In the BiVAD group, 59 (66%) patients had left ventricular apical cannulation, whereas 31 (34%) patients had left atrial cannulation. Right axillary artery was used as an outflow in all Ec-VAD patients. One patient required conversion of outflow to ascending aorta due to excessive bleeding from the axillary cannulation site. Femoral venous cannula was successfully weaned off after 5.3 ± 4.1 days of support in all patients except for one. One required conversion to percutaneous right VAD through the internal jugular vein due to sustained right ventricular dysfunction [5]. Mean systemic (left VAD) flow was equivalent between groups. Early clinical outcomes and late clinical outcomes Early clinical outcomes are listed in Table 3. Support duration was similar between groups. Patients in the BiVAD group were more likely to have major bleeding events including delayed sternal closure during support. Stroke rate was similar between groups. Multi-organ failure/sepsis and stroke were major causes of death during support. Thirty-day mortality was 24% in the BiVAD and 14% in the Ec-VAD (P = 0.39) group. Sixty-six patients (73%) in the BiVAD group reached to the next destination: myocardial recovery in 25 (28%), device exchange to a durable VAD in 29 (32%) and heart transplantation in 12 (13%), compared to 17 patients (77%) in the Ec-VAD group: myocardial recovery in 6 (27%), device exchange to a durable VAD in 10 (46%) and heart transplantation in 1 (4.6%) (P = 0.45). Overall survival at 1 year was 61% in Ec-VAD and 55% in BiVAD (Fig. 2) (P = 0.7). Impact of extracorporeal membrane oxygenation ventricular assist device on outcomes of bridge to durable ventricular assist device Because the initial purpose of Ec-VAD was to spare sternotomy to facilitate a subsequent definitive surgery, we performed a

4 1058 K. Takeda et al. / European Journal of Cardio-Thoracic Surgery Table 1: Baseline characteristics BiVAD (n = 90) Ec-VAD (n = 22) P-value Age (year) 52.5 ± ± Gender male, n (%) 65 (72.2) 17 (77.3) INTERMACS level, n (%) (80.0) 21 (95.5) 2 18 (20.0) 1 (4.55) Body mass index 28.4 ± ± Body surface area (m 2 ) 2.00 ± ± Coronary artery disease, n (%) 45 (50.0) 15 (68.2) Hypertension, n (%) 38 (42.2) 12 (54.4) Diabetes mellitus, n (%) 30 (33.3) 6 (27.3) Hyperlipidaemia, n (%) 33 (36.7) 7 (31.8) Aetiology of heart failure, n (%) Acute myocardial infarction 48 (53.3) 14 (63.6) Acute decompensated heart failure 31 (34.4) 7 (31.8) Myocarditis 11 (12.2) 1 (4.55) Preoperative IABP support, n (%) 52 (57.8) 5 (22.7) Preoperative ventilator support, n (%) 65 (74.7) 16 (72.7) 1.00 Preoperative percutaneous circulatory support, n (%) 40 (44.4) 18 (81.8) Femoral veno-arterial ECMO 28 5 Impella 3 3 Femoral veno-arterial ECMO and Impella 8 10 Others 1 0 Duration of percutaneous circulatory support (days) 2.57 ± ± WBC (1000/ml) 14.1 ± ± Haemoglobin (g/dl) 11.0 ± ± Haematocrit (%) 32.1 ± ± Platelets (1000/ml) 178 ± ± Sodium (mmol/l) 136 ± ± BUN (mg/dl) 30.4 ± ± Creatinine (mg/dl) 1.55 ± ± Total bilirubin (mg/dl) 2.36 ± ± Direct bilirubin (mg/dl) 1.07 ± ± Total protein (g/dl) 5.54 ± ± Albumin (g/dl) 3.12 ± ± AST (U/l) 356 ± ± ALT (U/l) 208 ± ± PT-INR 1.50 ± ± BiVAD: biventricular assist device; Ec-VAD: extracorporeal ventricular assist device; INTERMACS: Interagency Registry for Mechanically Assisted Circulatory Support; IABP: intra-aortic balloon pump; ECMO: extracorporeal membrane oxygenation; WBC: white blood cells; BUN: blood urea nitrogen; AST: aspartate transaminase; ALT: alanine transaminase; PT-INR: prothrombin time-international normalized ratio. subgroup analysis to elucidate the impact of Ec-VAD on outcomes of bridge to isolated continuous-flow left VAD (Table 4). End-organ function was similar between the 2 groups. Serum albumin level was lower in the Ec-VAD group (P = 0.06). HeartMate II (St Jude Medical, Inc., St Paul, MN, USA) was used in the majority of the patients. Cardiopulmonary bypass time for subsequent surgery was significantly longer in the BiVAD group, and transition from BiVAD to durable VAD required significantly larger amount of fresh frozen plasma and platelet infusions. The rate of postoperative temporary right VAD use and in-hospital mortality was higher in the BiVAD group, although the differences did not reach statistical significance. DISCUSSION This is a study to investigate the benefit of our unique approach to cardiogenic shock patients by comparing CentriMag Ec-VAD to conventional CentriMag BiVAD via sternotomy. Although the number of the Ec-VAD cohort is small, the present study demonstrates several potential benefits of this approach: Ec-VAD (i) can provide equivalent flow, support duration and mortality comparable to BiVAD; (ii) can provide superior results compared to BiVAD with respect to major bleeding events, blood product use and cardiopulmonary bypass use; and (iii) by sparing sternum, potentially facilitate a subsequent durable VAD surgery. Because of these benefits, Ec-VAD replaced conventional BiVAD to treat cardiogenic shock patients in our programme. Mortality for cardiogenic shock remains high. Recent advances in technology enabled us to treat shock patients with various percutaneous ST-MCS devices. In our programme, we prefer ECMO because of easy insertion and ability to provide highflow circulatory support [3, 6]. However, traditional femoral veno-arterial ECMO is limited by adverse haemodynamics due to increases in afterload with left ventricular loading rather than unloading. Another major limitation of femoral veno-arterial ECMO is the patient s immobility. Other percutaneous MCS systems also have their inherent limitations [2]. The external VAD using CentriMag is another attractive option for treating shock patients. This pump can generate 10 l/min of continuous flow at a low

5 K. Takeda et al. / European Journal of Cardio-Thoracic Surgery 1059 Table 2: Intraoperative variables BiVAD (n = 90) Ec-VAD (n = 22) P-value Use of cardiopulmonary 59 (65.6) 0 (0) bypass, n (%) Cardiopulmonary bypass 85.3 ± (0) time (min) Transfusion (unit) prbc 3.25 ± ± FFP 4.09 ± ± Platelets 12.6 ± ± Cannulation, n (%) LVAD inflow LV through LV apex 59 (65.6) 22 (100) LA 23 (25.6) 0 (0) LV through LA 8 (8.89) 0 (0) LVAD outflow Aorta 88 (97.8) 0 (0) Axillary artery 2 (2.22) 22 (100) RVAD inflow RA 90 (100) 0 (0) RA through femoral vein 0 (0) 22 (100) RVAD outflow Pulmonary artery 90 (100) 0 (0) Mean systemic flow (l/min) 5.71 ± ± BiVAD: biventricular assist device; Ec-VAD: extracorporeal ventricular assist device; prbc: packed red blood cells; FFP: fresh frozen plasma; LVAD: left ventricular assist device; LV: left ventricle; LA: left atrium; RVAD: right ventricular assist device; RA: right atrium; VAD: ventricular assist device. Table 3: Early outcomes and next destinations BiVAD (n = 90) Ec-VAD (n = 22) P-value Support duration, days 24.2 ± ± Major morbidity during support, n (%) Major bleeding 59 (71.9) 7 (31.8) Delayed sternal closure 34 (37.8) 0 (0) Stroke 13 (14.4) 4 (18.2) Mortality on device, n (%) 19 (21.1) 4 (18.2) 1.00 Multi-organ failure/sepsis 12 1 Stroke 7 2 Other 0 1 Thirty-day mortality, n (%) 22 (24.4) 3 (13.6) Destination, n (%) 66 (73.3) 17 (77.3) Recovery (weaned 25 (27.8) 6 (27.3) off device) Heart transplant 12 (13.3) 1 (4.55) Durable VAD 29 (32.2) 10 (45.5) Pulsatile LVAD 3 0 Continuous-flow LVAD Continuous-flow BiVAD 2 0 BiVAD: biventricular assist device; Ec-VAD: extracorporeal ventricular assist device; LVAD: left ventricular assist device; VAD: ventricular assist device. rotational speed of 5500 rpm. Various types of cannulas can be connected to the CentriMag system. These features allow easy insertion, flexible configuration, combination with an oxygenator, mid-term use and easy postoperative maintenance. We have previously reported our CentriMag VAD experience for various cardiogenic shock patients as a bridge to decision therapy. Outcome of our approach was favourable with 30-day survival of 69% and 1-year survival of 49% [3]. Biventricular support is preferred for patients in cardiogenic shock. However, BiVAD implantation requires sternotomy and cardiopulmonary bypass, which limits its emergent use and may be contraindicated in patients with severe coagulopathy or other relative contraindications to sternotomy. To overcome these drawbacks, we previously developed a minimally invasive apico-axillary CentriMag VAD insertion technique [7]. Saito et al. reported an apico-ascending aortic temporary VAD using ECMO circuit through a minimally invasive approach [8]. However, these techniques are reserved for patients who can be stabilized with isolated left VAD support. The use of percutaneous biventricular support with 2 Impella pumps was reported, but this technique is obviously limited with regard to patient mobility and support duration [9]. The advantage of our Ec-VAD technique is the ability to integrate right VAD with minimally invasive apico-axillary VAD. Moreover, once the patient is stabilized, we can easily convert Ec-VAD to apico-axillary VAD by eliminating venous limb and oxygenator (Fig. 1A and B). Then, the patient can participate in ambulatory rehabilitation and wait for a month for recovery. Compared to the BiVAD cohort, Ec-VAD patients were older and many patients had INTERMACS profile 1 [10]. Therefore, the Ec-VAD cohort was likely sicker than BiVAD cohort. Furthermore, more patients had percutaneous ST-MCS support before receiving CentriMag VAD (INTERMACS I TCS). This trend probably reflects change of our practice to treat cardiogenic shock patients during this study period. Percutaneous ST-MCS such as ECMO has gained more popularity as a primary resuscitation device for INTERMACS profile 1 patients. Currently, Ec-VAD is our primary mode of biventricular support for cardiogenic shock patients who cannot be optimized by percutaneous ST-MCS and need circulatory support longer than 1 week. We converted to Ec-VAD after 3.2 days of percutaneous ST-MCS supports including femoral veno-arterial and/or Impella. We believe that early conversion is better to provide powerful ventricular unloading effect and prolonged circulatory support with ambulatory rehabilitation. Patients with Ec-VAD required less transfusion, despite significantly lower preoperative platelet count. This is attributed to the minimally invasive approach without using cardiopulmonary bypass and sternotomy. Another interesting feature of Ec-VAD is that it can facilitate a subsequent durable VAD surgery as shown in Table 4. From our experiences, in patients with BiVAD, we often encountered dense adhesions around the cannula that certainly increased the surgical complexity when BiVAD was converted to durable VAD. Subgroup analysis showed that Ec-VAD significantly decreased the amount of transfusion and also cardiopulmonary bypass time. We found very minimal adhesion inside the pericardium when we converted Ec-VAD to durable VAD. Although the number of Ec-VAD patients who reached durable VAD is still small, there was no mortality associated with bridge to durable VAD surgery. The Ec-VAD provided lower 30-day mortality compared to BiVAD (13% vs 24%). Also, current study showed that Ec-VAD offers comparable mid-term survival to BiVAD. However, it failed to show significant survival benefit compared to BiVAD. This is likely related to baseline acuity of the cardiogenic shock cohort.

6 1060 K. Takeda et al. / European Journal of Cardio-Thoracic Surgery Figure 2: Overall survival comparison between BiVAD and Ec-VAD. 95% CI: 95% confidence interval. Ec-VAD: extracorporeal ventricular assist device; cbivad: conventional biventricular assist device. Table 4: left VAD Outcomes of bridge to isolated continuous-flow BiVAD (n = 24) Ec-VAD (n = 10) P-value Pre-CentriMag VAD variables Age (year) 52.4 ± ± Gender male, n (%) 19 (79.2) 8 (80.0) 1.00 BUN (mg/dl) 35 ± ± Creatinine (mg/dl) 1.58 ± ± Total bilirubin (mg/dl) 1.73 ± ± Albumin (g/dl) 3.17 ± ± AST (U/l) 463 ± ± ALT (U/l) 255 ± ± Pre durable VAD variables BUN (mg/dl) 20.5 ± ± Creatinine (mg/dl) 1.05 ± ± Total bilirubin (mg/dl) 1.37 ± ± Albumin (g/dl) 3.12 ± ± AST (U/l) 61.8 ± ± ALT (U/l) 51.7 ± ± Operative variables Device HeartMate II 20 (83.3) 10 (100) HeartWare 4 (16.7) 0 (0) Cardiopulmonary 146 ± ± bypass time (min) Transfusion (unit) prbc 5.54 ± ± FFP 5.76 ± ± PLT 17.4 ± ± Perioperative outcome Temporary RVAD use, n (%) 5 (20.8) 1 (10.0) In-hospital mortality, n (%) 4 (16.7) 0 (0) BiVAD: biventricular assist device; Ec-VAD: extracorporeal ventricular assist device; VAD: ventricular assist device; AST: aspartate transaminase; ALT: alanine transaminase; BUN: blood urea nitrogen; RVAD: right ventricular assist device; prbc: packed red blood cells; FFP: fresh frozen plasma; PLT: platelets. An important complication that we can improve is cerebrovascular accident. CentriMag VAD had a higher incidence of stroke when compared with implantable VAD [3]. In patients with Ec-VAD, we had 4 major strokes in the early series. Currently, we aggressively start anticoagulation therapy within 12 h after surgery and allow the aortic valve to open periodically by adjusting apical drainage flow and using inotropes to avoid aortic root thrombus formation. Further innovations in strategy and approach to improve survival is needed to treat these sickest population. Limitations There are several limitations of this study. First, it was a retrospective analysis of a single-centre experience. Second, the authors conducted sample number calculation to detect 30-day mortality difference between groups, revealing that our patient numbers are far less than those would be required for significant level of 0.05 and power 80%. Therefore, our results should be carefully interpreted for possible insufficient power. Third, because of the nature of single-centre studies, the outcomes described here are based on our practice in terms of patient selection, surgery and management. Therefore, our findings may not be applicable to other centres. Finally, this analysis between groups was historical comparison as our device strategy and patient management has changed over time. Therefore, calendar time bias was inevitable. As presented in Table 1, some baseline variables included significant differences, which may confound the results of the present study. Because of the retrospective nature, we could not overcome this limitation, and baseline adjustment such as propensity matching was unfortunately unfeasible due to small sample numbers. Further multicentre studies including larger number of patients is warranted to show true statistical significance.

7 K. Takeda et al. / European Journal of Cardio-Thoracic Surgery 1061 CONCLUSION In conclusion, our Ec-VAD approach can provide superior results compared with BiVAD with respect to major bleeding events, blood product use and cardiopulmonary bypass use. Conflict of interest: Y.N. has received consulting fees from St. Jude Medical Inc. The remaining authors have no conflicts of interest to disclose. REFERENCES [1] Stretch R, Sauer CM, Yuh DD, Bonde P. National trends in the utilization of short-term mechanical circulatory support: incidence, outcomes, and cost analysis. J Am Coll Cardiol 2014;64: [2] Werdan K, Gielen S, Ebelt H, Hochman JS. Mechanical circulatory support in cardiogenic shock. Eur Heart J 2014;35: [3] Takayama H, Soni L, Kalesan B, Truby LK, Ota T, Cedola S et al. Bridgeto-decision therapy with a continuous-flow external ventricular assist device in refractory cardiogenic shock of various causes. Circ Heart Fail 2014;7: [4] Takeda K, Garan AR, Topkara VK, Kirtane AJ, Karmpaliotis D, Kurlansky P et al. Novel minimally invasive surgical approach using external ventricular assist device and extracorporeal membrane oxygenation in refractory cardiogenic shock. Eur J Cardiothorac Surg 2017;151: [5] Kazui T, Tran PL, Echeverria A, Jerman CF, Iwanski J, Kim SS et al. Minimally invasive approach for percutaneous CentriMag right ventricular assist device support using a single PROTEKDuo Cannula. J Cardiothorac Surg 2016;11:123. [6] Truby L, Mundy L, Kalesan B, Kirtane A, Colombo PC, Takeda K et al. Contemporary outcomes of venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock at a large tertiary care center. ASAIO J 2015;61: [7] Takayama H, Naka Y, Jorde UP, Stewart AS. Less invasive left ventricular assist device placement for difficult resternotomy. J Thorac Cardiovasc Surg 2010;140: [8] Saito S, Fleischer B, Maeß C, Baraki H, Kutschka I. Minimally invasive implantation of an extracorporeal membrane oxygenation circuit used as a temporary left ventricular assist device: a new concept for bridging to permanent cardiac support. J Artif Organs 2015;18:95 8. [9] Kapur NK, Jumean M, Ghuloom A, Aghili N, Vassallo C, Kiernan MS et al. First successful use of 2 axial flow catheters for percutaneous biventricular circulatory support as a bridge to a durable left ventricular assist device. Circ Heart Fail 2015;8: [10] Stevenson LW, Pagani FD, Young JB, Jessup M, Miller L, Kormos RL et al. INTERMACS profiles of advanced heart failure: the current picture. J Heart Lung Transplant 2009;28: