Hrev_master Abstract We describe an unexpected complication in a 46-years-old man affected by ischemic cardiomyopathy who received a pro- longed mechanical cardiac support by means of right transaxillary Impella 5.0. The postoperative course was complicated by recur- rent septicemia from multi-durg resistant Acinetobacter baumanii. He underwent implantation of venoarterial extracorporeal mem- brane oxygenation because of refractory cardiac arrest, followed by Impella removal that has been complicated by embolic stroke. The likely source of the embolus was a large thrombus inside the innominate artery. After a long-standing right transaxillary device implantation, particularly in patients with intercurrent septic episodes, a CT angiographic scan should be planned to exclude arterial thrombosis before removal of the transarterial device. Introduction Intravascular devices for mechanical cardiac support are gain- ing increasing diffusion because they are minimally invasive and reliable. Here we describe an unexpected complication following a very long period of support by means of Impella 5.0 (Abiomed, Danvers, MA, USA) associated to recurrent sepsis. Case Report A 46-years-old Caucasian man was admitted to another Center due to a sub-acute myocardial infarction. Coronary angiogram showed severe multivessel disease. Stenting of the right coronary artery was performed. Nevertheless, left ventricular systolic func- tion remained poor being ejection fraction 15%. Because of refrac- tory cardiogenic shock, a temporary mechanical cardiac support was instituted through a transfemoral Impella CP (Abiomed, Danvers, MA, USA). Impella is a minimally invasive pump that is positioned retrogradely into the left ventricle from a peripheral artery. It can be inserted percutaneously or surgically. It increases the left ventricular output by generating an axial flow of blood up to 5 L/min from the left ventricle to the ascending aorta. The main indications to Impella are the support of a failing left ventricle, and during high-risk cardiac percutaneous interventions. Contraindications to it include significant aortic valve regurgita- tion or stenosis, a mechanical aortic valve prosthesis, a left ventric- ular thrombus and severe peripheral artery disease. After six days of support a malfunction of the device was detected due to inflow thrombosis. Therefore, Impella CP was removed and replaced with a right transaxillary Impella 5.0, surgically implanted through a vascular graft. The subsequent clinical course was complicated by septicemia due to Acinetobater baumanii. However, there was no signs of cardiac recovery and multiple attempts to wean the patient fromthe mechanical support resulted unsuccessful. During the cir- culatory support the level of anticoagulation remained within the therapeutic range. On the 52nd day of Impella 5.0 support, the patient was referred to our hospital to evaluate the indication to heart transplantation. A relapse of septicemia by multi-drug-resis- tant A. baumanii occurred. Considering the long-standing Impella support and being very likely the infection of the device by a multi- drug resistant pathogen, we decided to attempt a further weaning trial. However, it was complicated by a sudden refractory cardiac arrest, treated by means of reverting to Impella full support and an emergent institution of a femoral-femoral veno-arterial Extracorporeal Membrane Oxygenation (ECMO). Then the patient was brought in the operating room to remove the Impella. The pro- cedure was preceded by transesophageal echocardiography, which excluded cardiac or device thrombosis. The Impella was surgically removed according to the standard procedure: the device was with- drawn and, after a brief blood flushing, the vessel was transiently clamped to allow for vascular graft removal and patch reconstruc- tion of the axillary artery. Immediately after Impella extraction the near infrared spectroscopy brain monitoring showed a sudden drop in the right side signal. At the end of surgery the neurologic assessment of the patient revealed a left hemiplegia. Angio-CT scan showed distal occlu- sion of the right carotid artery, causing an extensive hemispheric stroke. Emergency Care Journal 2021; volume 17:9123 Correspondence: Aldo Cannata, Department of Cardiac Surgery, Niguarda Hospital, Piazza Ospedale Maggiore, 3, 20162 Milan, Italy. Tel.: +39.026444 2565. E-mail: aldo.cannata@ospedaleniguarda.it Key words: Arterial thrombosis; thromboembolism; mechanical circu- latory support; heart failure; sepsis. Contributions: AC and MC wrote the text; GT reviewed the relevant lit- erature; CFR reviewed the entire case report. Conflict of interest: No one. This work was not supported by any grant. Availability of data and materials: All data underlying the findings are fully available. Ethics approval: No ethical commitee approval was required for this case report by the Department. Received for publication: 20 May 2020: Revision received: 21 October 2020. Accepted for publication: 6 November 2020. This work is licensed under a Creative Commons Attribution 4.0 License (by-nc 4.0). ©Copyright: the Author(s), 2021 Licensee PAGEPress, Italy Emergency Care Journal 2021; 17:9123 doi:10.4081/ecj.2021.9123 [Emergency Care Journal 2021; 17:9123] [page 27] Thrombosis of the innominate artery during prolonged cardiac support by right transaxillary Impella 5.0 device Aldo Cannata, Massimiliano Carrozzini, Giuseppe Tata, Claudio Francesco Russo Department of Cardiac Surgery, Niguarda Hospital, Milan, Italy Non -co mmerc ial us e o nly A large molding thrombus was detected in the innominate artery (Figure 1). This massive stroke was the cause of the patient’s death. Discussion Transaxillary implantation of Impella 5.0, either performed surgi- cally of percutaneously, is gaining increasing acceptance as an effective method to unload the left ventricle.1-5 A relevant advantage of this access is the possibility of a full mobilization of patients, being this par- ticularly favourable in patients needing prolonged support awaiting heart transplantation.1 In some published series transaxillary implanta- tion of Impella 5.0 was performed thorough the right axillary artery.2,3 Complications have been observed during support with Impella, such as vascular injury at the site of insertion (pseudoaneurysm, hematoma, thrombosis, limb ischemia), rupture of mitral chords, injury to the aor- tic valve leaflets, hemolysis and thrombocytopenia. To the best of our knowledge, this is the first report of a thrombosis of the innominate artery occurred during support with transaxillary Impella 5.0. The angio-CT scan showed a large molding thrombus inside the innominate artery. Its shape suggests that it was surrounding the Impella 5.0 catheter and it was the most likely source of the emboli to the right carotid artery (Figure 1). The reported incidence of stroke in patients supported by a transaxillary Impella 5.0 is 10%.1,2 The risk of thrombo- sis of the innominate artery during support by means of right transax- illary Impella is still unknown. In our case the very long duration of the support with Impella and the hypercoagulable state associated to sepsis may have promoted the formation of intra-arterial thrombus. However, there are several published reports of patients successfully supported up to 35 days,3,6 far beyond the 14-days certification of Impella 5.0. Very recently Jones5 reported for the first time that the risk of thrombosis of the axillary artery was related to the duration of support by transaxillary Impella 5.0. The incidence of thrombosis was 21%, 67% and 75% for implant duration of 0-3, 4-7 and >7 days, respectively. Obviously, the clinical impact of thromboembolism from the innominate artery is very likely less benign as compared to a similar event arising from the axil- lary or the femoral artery because of the risk of stroke in the former case. The usual technique to remove a surgical transaxillary Impella is by withdrawing the device without preoperative imaging.3 Pre-removal axillary artery angiography has been reported only for percutaneous transaxillary Impella.4,5 Recently Ranganath7 described a case of suc- cessful embolic protection of both carotid arteries during the removal of a transaxillary Impella by means of embolic protection devices. These were adopted prophylactically and the authors did not perform a pre-removal angio-CT scan. In our case antegrade advancement of an embolic protection device would have been very risky because of the thrombus in the innominate artery. Alternatively, a surgical thrombec- tomy of the innominate artery just before the Impella removal could have been considered. Nevertheless, it would have been at high risk of bleeding as a consequence of anticoagulation required by the veno- arterial ECMO. Conclusions In conclusion, it seems advisable to perform an imaging study of the thoracic aorta and the involved epiaortic vessels just before the removal of a right transaxillary Impella 5.0, particularly for patients supported for more than 3 days, if the anticoagulation level has been suboptimal or in patients with recurrent sepsis. In case of thrombosis of the innominate artery the adoption of an embolic protection device or a surgical thrombectomy are potential options. Finally, it seems reason- able to prefer the implantation of the Impella through the left axillary artery whenever feasible, in order to decrease the risk of embolic carotid stroke. References 1. Chung JS, Emerson D, Ramzy D, et al. A new paradigm in mechanical circulatory support: 100 patient experience. Ann Thorac Surg 2020;109:1370-7. 2. Boll G, Fischer A, Kapur NK, Salehi P. Right Axillary Artery Conduit Is a Safe and Reliable Access for Implantation of Impella 5.0 Microaxial Pump. Ann Vasc Surg 2019;54:54-9. 3. Bertoglio L, Katsarou M, Scandroglio M, et al. Surgical transaxil- lary placement of the Impella 5.0 ventricular assist device. J Card Surg 2019;34:92-8. 4. Nakamura K, Krishnan S, Mahr C, McCabe JM. First-in-Man Percutaneous Transaxillary Artery Placement and Removal of the Impella 5.0 Mechanical Circulatory Support Device. J Invasive Cardiol 2017;29:E53-9. 5. Jones TL, Kearney KE, McCabe JM. Prevalence and Predictors of Vascular Thrombus Formation After Percutaneous Axillary Artery Impella Insertion. Circ Cardiovasc Interv 2019;12:e008046. 6. Castillo-Sang MA, Prasad SM, Singh J, et al. Thirty-five day Impella 5.0 support via right axillary side graft cannulation for acute cardiogenic shock. Innovations (Phila) 2013;8:307-9. 7. Ranganath NK, Moazami N, Staniloae CS, Hisamoto K. Successful embolic protection during temporary circulatory sup- port device removal in a patient who required holding of anticoag- ulation for postoperative hemothorax. J Thorac Cardiovasc Surg 2018;156:e203-4. Case Report Figure 1. Angio-CT scan of the chest performed immediately after the removal of the Impella. It is shown a thrombus involving half the lumen of the innominate artery (white arrow). The catheter mold is visible into the thrombus (black arrowhead). [page 28] [Emergency Care Journal 2021; 17:9123] Non -co mmerc ial us e o nly