Extracorporeal Life Support for Cardiogenic Shock or Cardiac Arrest Due to Acute Coronary Syndrome

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1 ORIGINAL ARTICLES: CARDIOTHORACIC ANESTHESIOLOGY: The Annals of Thoracic Surgery CME Program is located online at To take the CME activity related to this article, you must have either an STS member or an individual non-member subscription to the journal. Extracorporeal Life Support for Cardiogenic Shock or Cardiac Arrest Due to Acute Coronary Syndrome Shingo Sakamoto, MD, Norimasa Taniguchi, MD, Shunsuke Nakajima, MD, and Akihiko Takahashi, MD Departments of Cardiology and Cardiac Surgery, Sakurakai Takahashi Hospital, Hyogo, Japan Background. Few data are available on the clinical outcome of patients with acute coronary syndrome (ACS) complicated by refractory cardiogenic shock or cardiac arrest who receive percutaneous extracorporeal life support (ECLS). We investigated the in-hospital outcome and predictors of mortality in these patients. Methods. The investigation was a single-center, retrospective cohort study of 98 ACS patients who received ECLS to reverse hemodynamic collapse refractory to conventional treatment. Results. Circulatory status before ECLS introduction was cardiogenic shock in 34, ventricular fibrillation or pulseless ventricular tachycardia in 23, and asystole or pulseless electrical activity in 41. Ninety-four patients (95.9%) underwent emergency revascularization, including 92 who received percutaneous coronary intervention and 2 who received isolated coronary artery bypass grafting. Successful angioplasty was achieved in 65 of 92 patients (70.7%). Fifty-four patients (55.1%) were weaned from ECLS, and ECLS-related complications occurred in 35 (35.7%). All-cause in-hospital mortality rate was 67.3%, and the survival rate to hospital discharge was 32.7%. Multivariate analysis revealed that independent predictors of in-hospital mortality were unsuccessful angioplasty, asystole or pulseless electrical activity before ECLS introduction, and ECLS-related complications. Conclusions. Despite hemodynamic support with ECLS, patients with ACS complicated by cardiogenic shock or cardiac arrest refractory to conventional treatment had high mortality. However, the higher than 30% in-hospital survival rate in this extremely critical population indicates that ECLS might improve outcomes in ACS by saving the lives of patients in this specialized category. Unsuccessful angioplasty, asystole or pulseless electrical activity before ECLS introduction, and ECLSrelated complications were predictors of in-hospital mortality. (Ann Thorac Surg 2012;94:1 7) 2012 by The Society of Thoracic Surgeons Treatment of acute coronary syndrome (ACS) has been advancing with the development of pharmacologic agents and mechanical revascularization that have reduced mortality [1]. However, the clinical outcome of patients with ACS complicated by cardiogenic shock remains unsatisfactory despite high rates of early revascularization. Furthermore, the prognosis of patients who develop cardiac arrest is extremely poor [1, 2]. Mechanical circulatory support devices have become widely used for intensive treatment of patients with circulatory collapse refractory to conventional treatment. Extracorporeal life support (ECLS) has been used in the treatment of cardiac arrest refractory to resuscitation since the 1960s [3]. The development of a percutaneous system has enabled rapid implantation of the device, and improvements in membrane oxygenators and centrifugal Accepted for publication Jan 11, Address correspondence to Dr Sakamoto, Sakurakai Takahashi Hospital, Oikecho, Sumaku, Kobe, Hyogo , Japan; gsakamo@gmail.com. pumps have made this intervention widespread. In the current era, ECLS is indicated in patients with circulatory collapse caused by various conditions [4, 5]. Although several investigations of ECLS have shown encouraging clinical outcomes in both pediatric and adult patients [6, 7], only a few small-scale reports described the use of ECLS for patients with ACS complicated by cardiogenic shock or cardiac arrest [8, 9]. Accordingly, we evaluated in-hospital outcome and predictors of hospital mortality in a large, single-center, retrospective cohort of patients with ACS complicated by refractory cardiogenic shock or cardiac arrest who received ECLS support. Patients and Methods The Institutional Review Board of the Sakurakai Takahashi Hospital approved this study and informed consent was waived because the patients had life-threatening emergencies. Between January 2000 and December 2010, 2012 by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc

2 2 SAKAMOTO ET AL Ann Thorac Surg OUTCOME OF ACS PATIENTS RECEIVING ECLS 2012;94:1 7 Abbreviation and Acronyms ACS acute coronary syndrome(s) AMI acute myocardial infarction CABG coronary artery bypass grafting ECLS extracorporeal life support IABP intraaortic balloon pumping PCI percutaneous coronary intervention TIMI thrombolysis in myocardial infarction VF/VT ventricular fibrillation or ventricular tachycardia a total of 256 patients received ECLS at our hospital. From this cohort, patients who presented with ACS were included in the study. The following conditions excluded patients from the analysis: (1) ECLS was initiated more than 48 hours after admission; and (2) the reason for circulatory collapse was unrelated to ACS. For patients with episodes of ECLS reintroduction, only the data from the first episode were applied, except for the definition of successful weaning from ECLS, as described later. Acute coronary syndrome was defined as either acute myocardial infarction (AMI) or unstable angina pectoris. The AMI was defined as elevation of serum creatine phosphokinase to at least twice the normal level with the presence of ischemic symptoms or ischemic changes on electrocardiogram. ECLS System and Indications The ECLS system consists of a centrifugal pump, a polypropylene hollow-fiber membrane oxygenator, and a circuit that are heparin-bonded (Terumo Inc, Tokyo, Japan). The system is preorganized and easy to prime with crystalloid fluid (480 ml) within 5 minutes [10]. We have used a or 15-Fr arterial cannula with a length of 15 cm and an 18Fr venous cannula with a length of 50 cm, which are percutaneously inserted into femoral vessels using the Seldinger technique. Mechanical circulation is established with venous blood drainage from the right atrium and arterial blood return to the femoral artery. The ECLS team consisted of a cardiac surgeon, an interventional cardiologist, a clinical engineer (perfusionist), and nurses. All team members were called when patients with ACS (irrespective of hemodynamic status) or cardiac arrest arrived at the emergency department in the day shift. During the night shift, 2 cardiac surgeons who stayed in the hospital 24 hours a day could start ECLS until the team members arrived. Average time from the call to team members arrival was 15 to 25 minutes during the night shift. Our hospital has ECLS available at the emergency department, the catheterization laboratory, and the coronary care unit. Relative indications for ECLS introduction were the following: (1) refractory cardiogenic shock unresponsive to inotropic agents or intraaortic balloon pumping; and (2) witnessed cardiac arrest (regardless of rhythm) unresponsive to standard advanced cardiac life support. Cardiogenic shock was defined as persistent hypotension (systolic blood pressure 90 mm Hg) with clinical manifestation of hypoperfusion. Patients with terminal illness and those with do not resuscitate orders were considered contraindicated. Management During ECLS Support The ECLS flow rate was determined based on blood pressure, urine output, Swan-Ganz catheter parameters, and arterial blood gas analysis. Mean blood pressure was maintained at greater than 60 mm Hg. Routine intraaortic balloon pump placement was recommended without contraindication or inability to implant owing to the presence of arterial occlusion. The activated clotting time was maintained at 150 to 250 seconds with heparin administration. An antegrade reperfusion catheter was placed for distal limb perfusion in those with suspected limb ischemia (Fig 1). In procedures performed after January 2001, therapeutic mild hypothermia was induced in those with spontaneous circulation after cardiac arrest. Patients were cooled to a core temperature of 33 C to 34 C for 24 to 48 hours followed by rewarming over 24 hours. Successful weaning was defined as separation from ECLS without mortality over 24 hours. Patients who developed hemodynamic instability after weaning from ECLS were reintroduced. Successful weaning also included patients who succeeded in a second weaning even though the first weaning attempt failed. The ECLS-related complications were defined as cannula site complication (bleeding requiring transfusion of at least 2 units and inguinal skin infection), retroperitoneal hemorrhage, lower limb ischemia, and cerebral hemorrhage. Arterial tubing Side port Superficial femoral artery Perfusion catheter Fig 1. A perfusion catheter (4 or 5 Fr sheath introducer) is inserted into the proximal superficial femoral artery. The antegrade perfusion system is established by connecting the sheath introducer and side port of arterial tubing of the extracorporeal life support circuit.

3 Ann Thorac Surg SAKAMOTO ET AL 2012;94:1 7 OUTCOME OF ACS PATIENTS RECEIVING ECLS Table 1. Characteristics of Patients Who Survived Compared With Those Who Died Characteristic Total (n 98) Survived (n 32) Died (n 66) 3 p Value Age, years Age (48) 8 (25) 39 (9.1) Male gender 65 (66.3) 25 (78.1) 40 (60.6) Clinical presentation AMI 96 (98) 31 (96.9) 65 (98.5) Unstable angina 2 (2) 1 (3.1) 1 (1.5) Mechanical complication of AMI 11 (11.2) 3 (9.4) 8 (12.1) 1.0 Hypertension 44 (44.9) 13 (40.6) 31 (47) Diabetes mellitus 34 (34.7) 14 (43.8) 20 (30.3) 0.19 Previous myocardial infarction 6 (6.1) 1 (3.1) 5 (7.6) 0.66 Previous stroke 9 (9.2) 2 (6.3) 7 (10.6) Cardiogenic shock on arrival 28 (28.6) 10 (31.3) 18 (27.3) Cardiac arrest on arrival 36 (36.7) 8 (25) 28 (42.4) Diagnostic angiography 97 (99) 32 (100) 65 (98.5) 1.0 Culprit vessel LMCA 24 (24.5) 5 (15.6) 19 (28.8) LAD 35 (35.7) 12 (37.5) 23 (34.8) LCX 6 (6.1) 1 (3.1) 5 (7.6) RCA 26 (26.5) 12 (37.5) 14 (21.2) Double vessels 6 (6.1) 2 (6.3) 4 (6.1) No. of diseased vessels Emergency PCI 92 (93.9) 30 (93.8) 62 (93.9) 1.0 Successful angioplasty 65 (66.3) 27 (84.4) 38 (57.6) Isolated emergency CABG 2 (2) Surgical repair 7 (7.1) 3 (9.4) 4 (6.1) 0.68 Data are presented as n (%) or mean SD. AMI acute myocardial infarction; CABG coronary artery bypass grafting; LAD left anterior descending; LCX left circumflex; LMCA left main coronary artery; PCI percutaneous coronary intervention; RCA right coronary artery. Coronary Revascularization Diagnostic angiography was performed unless there was prolonged asystole or pulseless electrical activity (PEA) after ECLS introduction. Percutaneous coronary intervention (PCI) was attempted when TIMI (thrombolysis in myocardial infarction) flow grade of acute coronary syndrome-related artery was less than 3 or the culprit lesion was considered to be an unstable lesion. Successful angioplasty was the achievement of a minimum stenosis diameter of less than 20% in the presence of TIMI grade 3 flow. Isolated emergency coronary artery bypass grafting (CABG) was performed in patients with complex coronary anatomy unsuitable for PCI. Surgical repair took place in patients with mechanical complications of AMI, including left ventricular free wall rupture, ventricular septal rupture, and papillary muscle rupture. Concomitant CABG was performed at the discretion of the operator. Statistical Analysis Values are presented as mean SD for continuous variables, and as numbers and percentages for categoric variables. Differences between the 2 groups were assessed by the Student t test or the Mann-Whitney U test for continuous data and by the 2 test for categoric variables. The Fisher exact test was used when expected counts in greater than 20% of cells were less than 5. Multivariate logistic regression analysis was used to identify the independent predictors of inhospital mortality. From the univariate analysis, variables with a value of p less than 0.1 were entered into a stepwise multivariate model. All probability values were 2-sided, and probability values of p less than 0.05 were considered statistically significant. Statistical analysis was performed using SPSS version 12.0 (SPSS Inc, Chicago, IL). Results Patient Characteristics During the period selected for study, 98 patients were eligible for inclusion. Baseline characteristics are shown in Table 1. Mean age was years. On hospital arrival, 28 patients (28.6%) had cardiogenic shock, and 36 (36.7%) had cardiac arrest. Emergency PCI was performed in 92 patients and isolated emergency CABG in 2. The remaining 4 patients did not undergo revascularization because 1 had AMI caused by refractory coronary spasm, 1 died of left ventricular free wall rupture before surgery, and 2 received surgical repair for left ventricular

4 4 SAKAMOTO ET AL Ann Thorac Surg OUTCOME OF ACS PATIENTS RECEIVING ECLS 2012;94:1 7 Table 2. Extracorporeal Life Support Data for Patients Who Survived Compared With Those Who Died Variables Total (n 98) Survived (n 32) Died (n 66) p Value Clinical situation of ECLS implantation Hospital arrival 44 (44.9) 10 (31.3) 34 (51.5) During PCI 33 (33.7) 15 (46.9) 18 (27.3) After PCI 20 (20.4) 7 (21.9) 13 (19.7) After left ventricular repair 1 (1) 0 1 (1.5) Location of ECLS implantation Emergency room 41 (41.8) 10 (31.3) 31 (47) Catheterization laboratory 35 (35.7) 15 (46.9) 20 (30.3) Coronary care unit 21 (21.4) 6 (18.8) 15 (22.7) Ward 1 (1) 1 (3.1) 0 Circulatory status before ECLS introduction Cardiogenic shock 34 (34.7) 14 (43.8) 20 (30.3) VF/VT 23 (23.5) 13 (40.6) 10 (15.2) Asystole/PEA 41 (41.8) 5 (15.6) 36 (54.5) Time from circulatory collapse to ECLS initiation, minutes Duration of ECLS support, hours Intra-aortic balloon pumping 94 (95.9) 32 (100) 62 (93.9) 0.3 Therapeutic hypothermia 41 (41.8) 15 (46.9) 26 (39.4) ECLS-related complications 35 (35.7) 5 (15.6) 30 (45.5) Cannula site complication 23 (23.5) 3 (9.4) 20 (30.3) Retroperitoneal hemorrhage 4 (4.1) 0 4 (6.1) Lower limb ischemia 7 (7.1) 1 (3.1) 6 (9.1) Cerebral hemorrhage 3 (3.1) 1 (3.1) 2 (3) Data are presented as n (%) or mean SD. ECLS extracorporeal life support; PCI percutaneous coronary intervention; PEA pulseless electrical activity; VF/VT ventricular fibrillation or pulseless ventricular tachycardia. free wall rupture without revascularization. Successful angioplasty was achieved in 65 of 92 patients (70.7%). Reasons for unsuccessful angioplasty were the absence of final TIMI grade 3 flow in 26 and severe residual stenosis owing to coronary artery dissection in 1. Mechanical complications of AMI were detected in 11 patients (7 left ventricular free wall rupture, 3 ventricular septal rupture, and 1 papillary muscle rupture), including 4 patients who underwent emergency PCI. Of these, 7 patients underwent surgical repair, including 2 who underwent concomitant CABG. Table 2 shows the characteristics of the ECLS data. Circulatory status before ECLS introduction was cardiogenic shock in 34 (34.7%), ventricular fibrillation or pulseless ventricular tachycardia (VF or VT) in 23 (23.5%), and asystole or PEA in 41 (41.8%). The mean time from circulatory collapse to ECLS initiation was minutes. Thirty-seven ECLS-related complications occurred in 35 patients. In-Hospital Outcome Twelve patients required ECLS reintroduction to maintain hemodynamic conditions within 24 hours after initial weaning. A total of 54 patients (55.1%) weaned from ECLS. The mean duration of ECLS support was hours. None of the patients underwent heart transplantation. A total of 22 patients died after weaning from ECLS (multiorgan failure in 17, sepsis in 4, and heart failure in 1). All-cause in-hospital mortality was observed in 66 patients (67.3%). A total of 32 patients (32.7%) survived to hospital discharge with a mean duration of stay of days after admission. Predictors of Hospital Survival Univariate analysis of baseline characteristics and ECLS data revealed that age ( 75 years), male gender, cardiac arrest on arrival, successful angioplasty, circulatory status before ECLS introduction, time from circulatory collapse to ECLS initiation, duration of ECLS support, and ECLS-related complications were factors with statistically significant differences (p 0.1) between patients who survived to hospital discharge and those who died. Age was entered into the multivariate analysis as the categoric variable (age 75 years). Duration of ECLS support was excluded from multivariate analysis because patients who could not wean from ECLS inevitably required ECLS support until death because no patients received heart transplantation. In general, most of these patients had ECLS support of a longer duration than that of patients who survived. To analyze this variable as a predictor of outcome would, therefore, have been inappropriate. Multivariate analysis revealed that the independent predictors of in-hospital mortality were the absence of successful angioplasty (unsuccessful angioplasty: odds ratio [OR], 6.67; 95% confidence interval [CI],

5 Ann Thorac Surg SAKAMOTO ET AL 2012;94:1 7 OUTCOME OF ACS PATIENTS RECEIVING ECLS Table 3. Independent Variables Associated With In-Hospital Mortality Variable OR 95% CI p Value Unsuccessful angioplasty Asystole or PEA before ECLS introduction ECLS-related complications CI confidence interval; ECLS extracorporeal life support; OR odds ratio; PEA pulseless electrical activity to 28.2), asystole or PEA before ECLS introduction (OR, 6.31; 95% CI, 1.80 to 21.2), and ECLS-related complications (OR, 4.72; 95% CI, 1.39 to 16.1) (Table 3). Comment This retrospective analysis of data from 98 patients with ACS complicated by cardiogenic shock or cardiac arrest refractory to conventional therapy who received ECLS support and mostly underwent early revascularization revealed high in-hospital mortality; however, it also showed a higher than 30% in-hospital survival in an extremely critical population of patients. Additionally, the data show that unsuccessful angioplasty, asystole or PEA before ECLS introduction, and ECLS-related complications are independent predictors of in-hospital mortality. Cardiogenic shock occurred in 5% to 10% of patients with ACS and remains the leading cause of in-hospital mortality in these patients [11]. Previous data show that early revascularization improved the clinical outcome of patients who presented with cardiogenic shock as well as those who were resuscitated after cardiac arrest [2, 12, 13]. Compared with these studies, our study shows higher in-hospital mortality despite the majority of patients having undergone early revascularization. This difference in results can be attributed to variations in age distribution and hemodynamic severity in the study populations. The mean age of this study population was relatively high, and age is one of the important predictors of prognosis for patients with ACS [14]. The hemodynamics of the population were not only cardiogenic shock or cardiac arrest but also the failure of conventional therapy, including cardiac resuscitation. These critically ill patients are expected to have a poorer prognosis and were excluded from the vast majority of studies of ACS. Our results indicate, however, that treatment with ECLS might further improve the outcome of ACS patients by saving lives in an extremely critical population who might otherwise die with only conventional therapy. Patients with cardiac arrest have a worse outcome than those with cardiogenic shock regardless of ECLS support [15]. Initial rhythm is strongly associated with outcome in out-of-hospital as well as in-hospital cardiac arrest, and patients with VF or VT have a better prognosis than those with asystole or PEA [7]. These indicators are consistent with our findings that the survival rate of patients who developed cardiogenic shock and cardiac arrest (VF or VT, asystole or PEA) before ECLS introduction were 41.2% and 28.1% (56.5%, 12.2%), respectively. Our findings also demonstrate that patients with ACS complicated by asystole or PEA still have an extremely poor prognosis despite ECLS support, suggesting that discretion should be given to ECLS implantation in these patients and that alternative strategies might be needed. Results of the SHOCK (should we emergently revascularize occluded coronaries for cardiogenic shock) trial have revealed that invasive strategies were not associated with improved prognosis among patients older than 75 years [12]; however, several studies have demonstrated benefits of revascularization in elderly patients [16, 17]. Indications for ECLS in this population are also controversial because of the lack of established guidelines. Many previous studies have excluded patients aged 75 years or greater [7, 18]. Conversely, some investigations have shown that the survival of patients aged 75 years or greater was similar to that of younger patients [19, 20]. We do not consider age 75 years or greater alone as an absolute contraindication to ECLS thus far because some patients in this population maintain a high level of physical activity without severe preexisting illness until just before they develop ACS. In addition, average life expectancy in Japan exceeds 80 years. Indeed, our results did not demonstrate that age 75 years or greater was an independent predictor of hospital mortality, but the clinical decision about ECLS implantation in elderly patients should be made individually with careful consideration of all factors. Our results showed that cannulation site bleeding caused the majority of ECLS-related complications. The relatively higher incidence of bleeding complications in this study might have been influenced by the fact that the majority of patients received dual antiplatelet therapy in addition to continuous heparin administration. Furthermore, rapid and accurate insertion of a cannula into the femoral vessel in emergency settings is still challenging in patients with cardiogenic shock and cardiac arrest under resuscitation because of insufficient pulsation of the femoral artery. Repeated puncture can cause bleeding from the sites after ECLS initiation with heparin administration. Accurate surgical cutdown might decrease the occurrence of cannulation site bleeding; however, a previous study reported that compared with surgical insertion, percutaneous insertion was associated with better hospital survival [21]. Although data are lacking, ultrasound-guided cannulation might be an effective method for decreasing cannulation site complications [22]. Extracorporeal life support may limit the ability to provide adequate decompression of the heart with severely depressed left ventricular function [23]. Attempts to decompress the left ventricle by increasing ECLS flow may paradoxically worsen the hemodynamic condition. Increasing flow of the pump can decrease cardiac preload; however, it can conversely increase the left ventricular afterload. The increment of afterload can exacerbate left ventricular dilatation and result in pulmonary edema. Therefore, cardiac response during ECLS sup- 5

6 6 SAKAMOTO ET AL Ann Thorac Surg OUTCOME OF ACS PATIENTS RECEIVING ECLS 2012;94:1 7 port must be considered, especially in patients with depressed myocardial function. Previous studies reported that atrial septostomy is useful for left ventricular decompression [22, 23] and may reduce ischemic injury and improve myocardial recovery. This study showed a poor survival rate for patients who developed terminal circulatory collapse despite the fact that most patients underwent coronary revascularization. Although successful angioplasty was demonstrated to be an independent predictor of hospital survival in our study, coronary revascularization may not always be essential after stabilization of a hemodynamic condition with a circulatory support device. Most of these patients require heart transplantation because myocardial recovery is not probable. However, ECLS as well as ventricular assist device implantation as a device of bridge to heart transplantation for ACS patients has been challenging in Japan because the number of donor hearts is limited and patients over 60 years old are generally ineligible. Therefore, under the standard of care in Japan, myocardial salvage (revascularization) is required to preserve myocardial function and to wean from ECLS instead of bridge therapy to heart transplantation. The present study has several limitations. First, this study was retrospective and therefore shares the limitations of all retrospective analyses. Prospective randomized trials are warranted to evaluate the efficacy of ECLS implantation in patients with refractory cardiogenic shock or cardiac arrest. However, such studies might be challenging to conduct because of the difficulty in randomizing patients in this extremely critical population. Second, the study lacked assessment of hemodynamic parameters during ECLS support to confirm the hemodynamic improvement. However, we treated patients individually according to hemodynamic parameters as previously mentioned. Finally, none of the patients underwent ventricular assist device implantation or heart transplantation. Strategy of using ECLS followed by bridge therapy with a ventricular assist device implantation was reported to have a favorable outcome [23]. However, the bridge therapy for ACS patients has been quite rare in Japan, as previously described. This limitation is an important issue that can hamper improvement in the outcome of these patients. References 1. Babaev A, Frederick PD, Pasta DJ, et al. Trends in management and outcomes of patients with acute myocardial infarction complicated by cardiogenic shock. JAMA 2005; 294: Dumas F, Cariou A, Manzo-Silberman S, et al. Immediate percutaneous coronary intervention is associated with better survival after out-of-hospital cardiac arrest: insights from the PROCAT (Parisian Region Out of hospital Cardiac ArresT) registry. Circ Cardiovasc Interv 2010;3: Kennedy JH. The role of assisted circulation in cardiac resuscitation. JAMA 1966;197: Chen YS, Yu HY, Huang SC, et al. Experience and result of extracorporeal membrane oxygenation in treating fulminant myocarditis with shock: what mechanical support should be considered first? J Heart Lung Transplant 2005;24: Ko WJ, Lin CY, Chen RJ, Wang SS, Lin FY, Chen YS. Extracorporeal membrane oxygenation support for adult postcardiotomy cardiogenic shock. Ann Thorac Surg 2002; 73: Thiagarajan RR, Laussen PC, Rycus PT, Bartlett RH, Bratton SL. Extracorporeal membrane oxygenation to aid cardiopulmonary resuscitation in infants and children. Circulation 2007;116: Chen YS, Lin JW, Yu HY, et al. Cardiopulmonary resuscitation with assisted extracorporeal life-support versus conventional cardiopulmonary resuscitation in adults with inhospital cardiac arrest: an observational study and propensity analysis. Lancet 2008;372: Fujimoto K, Kawahito K, Yamaguchi A, et al. Percutaneous extracorporeal life support for treatment of fatal mechanical complications associated with acute myocardial infarction. Artif Organs 2001;25: Chen JS, Ko WJ, Yu HY, et al. Analysis of the outcome for patients experiencing myocardial infarction and cardiopulmonary resuscitation refractory to conventional therapies necessitating extracorporeal life support rescue. Crit Care Med 2006;34: Nishida H, Shibuya M, Kitamura M, et al. Percutaneous cardiopulmonary support as the second generation of venoarterial bypass: current status and future direction. Artif Organs 1993;17: Jeger RV, Radovanovic D, Hunziker PR, et al. Ten-year trends in the incidence and treatment of cardiogenic shock. Ann Intern Med 2008;149: Hochman JS, Sleeper LA, Webb JG, et al. Early revascularization in acute myocardial infarction complicated by cardiogenic shock. SHOCK Investigators. Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock. NEngl J Med 1999;341: Garot P, Lefevre T, Eltchaninoff H, et al. Six-month outcome of emergency percutaneous coronary intervention in resuscitated patients after cardiac arrest complicating ST-elevation myocardial infarction. Circulation 2007;115: Alexander KP, Newby LK, Cannon CP, et al. Acute coronary care in the elderly, part I: Non-ST-segment-elevation acute coronary syndromes: a scientific statement for healthcare professionals from the American Heart Association Council on Clinical Cardiology: in collaboration with the Society of Geriatric Cardiology. Circulation 2007; 115: Nichol G, Karmy-Jones R, Salerno C, Cantore L, Becker L. Systematic review of percutaneous cardiopulmonary bypass for cardiac arrest or cardiogenic shock states. Resuscitation 2006;70: Dzavik V, Sleeper LA, Picard MH, et al. Outcome of patients aged or 75 years in the SHould we emergently revascularize Occluded Coronaries in cardiogenic shock (SHOCK) trial: do elderly patients with acute myocardial infarction complicated by cardiogenic shock respond differently to emergent revascularization? Am Heart J 2005;149: Dzavik V, Sleeper LA, Cocke TP, et al. Early revascularization is associated with improved survival in elderly patients with acute myocardial infarction complicated by cardiogenic shock: a report from the SHOCK Trial Registry. Eur Heart J 2003;24: Nagao K, Hayashi N, Kanmatsuse K, et al. Cardiopulmonary cerebral resuscitation using emergency cardiopulmonary bypass, coronary reperfusion therapy and mild hypothermia in patients with cardiac arrest outside the hospital. J Am Coll Cardiol 2000;36: Saito S, Nakatani T, Kobayashi J, et al. Is extracorporeal life support contraindicated in elderly patients? Ann Thorac Surg 2007;83:140 5.

7 Ann Thorac Surg SAKAMOTO ET AL 2012;94:1 7 OUTCOME OF ACS PATIENTS RECEIVING ECLS 20. Shinn SH, Lee YT, Sung K, et al. Efficacy of emergent percutaneous cardiopulmonary support in cardiac or respiratory failure: fight or flight? Interact Cardiovasc Thorac Surg 2009;9: Thiagarajan RR, Brogan TV, Scheurer MA, Laussen PC, Rycus PT, Bratton SL. Extracorporeal membrane oxygenation to support cardiopulmonary resuscitation in adults. Ann Thorac Surg 2009;87: Massetti M, Tasle M, Le Page O, et al. Back from irreversibility: extracorporeal life support for prolonged cardiac arrest. Ann Thorac Surg 2005;79: Pagani FD, Aaronson KD, Swaniker F, Bartlett RH. The use of extracorporeal life support in adult patients with primary cardiac failure as a bridge to implantable left ventricular assist device. Ann Thorac Surg 2001;71 (Suppl 3): S INVITED COMMENTARY The article by Dr Sakamoto and associates [1] studies retrospectively the outcome of 98 ACS [acute cardiogenic shock] patients who required ECLS [extracorporeal life support] for hemodynamic collapse unresponsive to conventional treatments. The study spans a 10-year period (2000 to 2010) and includes a wide spectrum of patients from cardiogenic shock being treated resistant VF or pulseless VT [ventricular fibrillation or ventricular tachycardia] and asystole. Of note, the majority (95.9%) of patients received emergency revascularization; 92 by PCI [percutaneous coronary intervention] and 2 undergoing coronary artery bypass grafting CABG [coronary artery bypass grafting. Successful angioplasty was defined by achieving a minimum stenosis diameter reduction less than 20% with (TIMI [thrombolysis in myocardial infarction] grade 3 flow. Adjunctive care after 2001 included Arctic Sun (Medivance, Inc, Louisville, CO) protocol for cerebral protection. Outcomes analyses included all-cause in-hospital mortality as well as successful eventual weaning from ECLS, and related complications defined as cannula site problems, retroperitoneal hemorrhage, ischemia, and cerebral hemorrhage. Data were analyzed by Student t test as well univariant and multivariant logistic regression analyses. The results are disappointing but not unexpected. In-hospital mortality using ECLS (average duration hours) was 67.3%. Mean time to initiation of ECLS was minutes. Thirty-seven percent survived to hospital discharge, with no patient receiving an LVAD [left ventricular assist device] or transplant. The study does not include echo data to determine adequate decompression of the LV or management of this problem (Impella [ABIOMED, Inc, Danvers, MA], decompressive septostomy, etc) However, the study has important points to be emphasized and the reason for cardiac surgeons to understand its lessons: (1) Prolonged cardiogenic shock (as pointed out in the SHOCK trial) carries a high mortality without a plan for definitive additional therapy. (2) Revascularization in the setting of cardiogenic shock provides little or no additional benefit and in the short term may be detrimental by delaying definitive support. (3) Extracorporeal life support is an effective method of early resuscitation of the moribund patients in shock but its effectiveness depends on brain and other organ ischemic time, ventricular recovery early, or use of more definitive devices for longterm support. Thus, the paper presents disappointing results for the sole use of ECLS and PCI in the setting of ACS. Current experience (personal institutional data) would suggest that, whenever possible, aggressive initiation of ECLS (to minimize brain ischemia) could improve survival rates to 70% to 80% utilizing biventricular (B)VAD/LVAD therapy when necessary, with transplant as a long-term possibility in some cases. The authors recognized the limitation of their approach, citing the use of LVAD/ BVAD support for ACS was rare in Japan during this time period as well as the limited effectiveness of emergency PCI. The paper solidifies the conclusions of the SHOCK trial and further emphasizes to cardiac surgeons that proactive, rapid support of patients with ACS for short periods is critical for end-organ preservation and, if neurologic viability is present, early conversion to BVAD/LVAD systems if they are not recovering myocardial function will markedly improve patient outcome and survival. George L Hicks, MD Division of Cardiothoracic Surgery University of Rochester Medical Center 601 Elmwood Ave Rochester, NY george_hicks@urmc.rochester.edu Reference 1. Sakamoto S, Taniguchi N, Nakajima S, Takahashi A. Extracorporeal life support for cardiogenic shock or cardiac arrest due to acute coronary syndrome. Ann Thorac Surg 2012;94: by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc