Ventricular assist devices are therapeutic alternatives. Neurosurgical complications of left ventricular assist devices in children.

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1 J Neurosurg Pediatrics 10: , 2012 Neurosurgical complications of left ventricular assist devices in children Clinical article Rory R. Mayer, B.S., 1 Steven W. Hwang, M.D., 1 Gaddum D. Reddy, M.D., Ph.D., 1 David L. Morales, M.D., 2 William E. Whitehead, M.D., M.P.H., 1 Daniel J. Curry, M.D., 1 Robert J. Bollo, M.D., 1 Thomas G. Luerssen, M.D., 1 and Andrew Jea, M.D. 1 1 Division of Pediatric Neurosurgery, Department of Neurosurgery; and 2 Division of Cardiovascular Surgery, Department of Surgery, Texas Children s Hospital, Baylor College of Medicine, Houston, Texas Object. Left ventricular assist devices (LVADs) are continuous or pulsatile flow devices that could potentially be life-saving measures for patients with end-stage heart failure. These devices have clear advantages over extracorporeal membrane oxygenation (ECMO) and are often used in adults. They are only recently being commonly used in the pediatric age group. As the use of LVADs becomes more mainstream in children, it is important to determine the complication profile associated with these devices. Furthermore, with the increasing application of LVADs in children, pediatric neurosurgeons are seeing a correlative increase in associated neurological complications. In this study, the authors reviewed the incidence of neurological complications due to LVAD use in the pediatric age group and the role of neurosurgery in treatment. Methods. The authors examined data regarding patients with LVADs from the Texas Children s Hospital Heart Center database (July 01, 2007, to June 30, 2011) and recorded neurological complications requiring neurosurgical consultation. They identified 2 children who underwent craniotomies during LVAD treatment. Results. Intracranial hemorrhage occurred in 3 (6.5%) of the 46 patients treated with an LVAD at the authors institution. Of these patients, 2 were treated with craniotomies for life-threatening intracranial hemorrhages. The 3 patients in the neurosurgical cohort presented with cerebral infarction, decreased level of consciousness, and/or seizure. At the last follow-up (286, 503, and 550 days), 1 patient ( 2) had no decline in neurological status, underwent a successful heart transplant, and was discharged home; 1 patient ( 1) died of refractory cardiac failure; and 1 patient ( 3) was on an LVAD for destination therapy (that is, the LVAD is not a bridge to transplantation but rather the final treatment). This patient was discharged from the hospital, but he died of overwhelming fungemia at 286 days while on VAD support. Conclusions. Intracranial hemorrhage is a serious and feared complication of LVAD treatment. While the surgical risk is substantial due to systemic anticoagulation and significant medical comorbidities, neurosurgical evacuation of hemorrhage plays an important life-saving role that can yield successful and acceptable outcomes. ( Key Words complication stroke intracranial hemorrhage left ventricular assist device pediatric neurosurgery Ventricular assist devices are therapeutic alternatives for children who have medically refractory heart failure and are awaiting cardiac transplantation. Ventricular assist devices are pumps that support cardiac output by being connected to either or both ventricles. The pump can be implanted intracorporeally or outside the body and is usually attached to an external battery. The circulatory flow generated by VADs can be either continuous or pulsatile. Even though there has been significant progress with adult VADs, experience and use of the pneumatic pulsatile and continuous flow circulatory Abbreviations used in this paper: ECMO = extracorporeal membrane oxygenation; ICH = intracranial hemorrhage; LVAD = left ventricular assist device; SDH = subdural hematoma. support is still limited in children. 13,24,28 There are several limitations of using these devices directly in children, including small body surface area and problems related to the overall size of the device that often preclude the ability to safely implant intracorporeal devices. Furthermore, decreased stroke volume requirements in children result in an increased risk of thromboembolic events from insufficient washout of VAD pump components. 4,9,29 Until recently, ECMO had been the mainstay of the pediatric circulatory support strategy. 6 Extracorporeal membrane oxygenation differs from a VAD in that it involves cannulation of the venous system (and sometimes the arterial system as well), allowing for extracorporeal oxygenation of the blood. However, the ability of ECMO to bridge children to transplant is quite limited due to increased 370 J Neurosurg: Pediatrics / Volume 10 / November 2012

2 Neurosurgical complications of LVADs in children complications when used for more than 2 weeks, and the use of pulsatile and continuous flow VADs in children has been increasing. Furthermore, some pulsatile VADs have successfully evolved into effective long-term bridges toward heart transplantation. 2 Neurological events and ischemic or hemorrhagic strokes are among the most commonly reported and morbid complications after LVAD placement in adults. 15,18 Patients typically undergo anticoagulation therapy with heparin and occasionally with adjuvant antiplatelet agents. However, there are limited data regarding the risk of neurological complications in children with VADs. Malaisrie et al. 19 described their institutional experience in 8 children. All patients in that study underwent anticoagulation with heparin or warfarin and 1 or more antiplatelet agents; 5 (62.5%) of the 8 patients had postoperative neurological events. In another small study, 10 children underwent bridge to transplantation with pneumatic paracorporeal systems, and 4 suffered neurological events. 3 In contrast, the published European experience has documented a much lower incidence of neurological complications associated with VADs. Hetzer et al. 14 observed only 4 cerebral strokes in 36 patients (11.1%) who survived to undergo either transplantation or device weaning. Moreover, due to the paucity of data regarding neurological complications of VADs in children, there are no clear neurosurgical recommendations to guide management and operative indications for ongoing neurological deficits in this very high risk population that requires continuous anticoagulation and antiplatelet therapy. Many believe that surgery, especially neurosurgery, is ill advised for patients undergoing anticoagulation therapy for VAD support. The purpose of our study was to describe the surgical treatment of patients who underwent craniectomy to evacuate ICHs that developed during LVAD therapy and to discuss associated perioperative management strategies. Methods We retrospectively reviewed the records of 3 consecutive patients who developed ICHs after undergoing LVAD placement (EXCOR, Berlin Heart or HeartMate II, Thoratec) at Texas Children s Heart Center (July 1, 2007, to June 30, 2011), and we cross-referenced them to our neurosurgery database. Patient demographics, neurological complications, details of the operative record, and follow-up reports were extracted and recorded. Of 46 patients in the heart center database, only 3 experienced neurological complications related to LVAD use that required neurosurgical consultation. We were not privy to data for patients with neurological complications who did not require neurosurgical consultation because they are enrolled in a separate investigational study. At the time of this study, LVAD data were sealed and subject to ongoing study for FDA approval. The data collected included patient demographic information, indications for LVAD placement, type of anticoagulation therapy, complications during LVAD use, and neurological and cardiac outcomes. We recorded the neurological complications of LVADs that included CNS hemorrhage as diagnosed on J Neurosurg: Pediatrics / Volume 10 / November 2012 head CT scans, CNS infarction diagnosed on head CT scans, clinically evident seizures, and subclinical seizures seen on electroencephalography only. In addition, the records of 2 patients in our database who underwent craniotomy during LVAD use were identified. Details of the medical and surgical treatment of these patients were recorded. Institutional review board approval was obtained for this study. Results Patient Presentation The mean age of the 3 patients at the time of LVAD placement was 67.0 months (4, 6, and 191 months), and the mean age at the time of neurological complication requiring neurosurgical evaluation was 68.0 months (5, 7, and 192 months); 2 patients were female, and one was male. Two patients had undergone placement of an EX- COR pediatric VAD, and one patient received a Heart- Mate II VAD (Table 1). The mean interval between LVAD implantation and clinical presentation of intracranial pathology was 23.7 days (range days). Signs and symptoms of neurological complications included seizures, decreased interactive play, and decreased responsiveness. All patients seen by neurosurgeons in this series presented with ICH. All 3 patients had SDHs, and 1 patient also had an intraparenchymal hemorrhage and ischemic stroke. Seizures were documented in 1 patient (Table 2). Medical Management at the Time of Complication The 3 patients who experienced intracranial hemorrhagic complications were taking therapeutic doses of heparin; 1 was also taking aspirin. In the 2 patients who required operative intervention because of deteriorating neurological examination findings, anticoagulation was fully reversed in one patient ( 2) and discontinued but not reversed in the other ( 3). Prothrombin time and activated partial thromboplastin time were optimized using fresh frozen plasma and vitamin K for surgery. Postoperatively, daily platelet transfusions were administered to maintain a level higher than /L. Cryoprecipitate infusions were ordered for fibrinogen counts of less than 150 mg/dl. Daily postoperative laboratory examinations included lactate dehydrogenase and plasma hemoglobin to monitor for signs of intrapump thrombus formation. After craniotomy, one patient ( 2) restarted anticoagulation therapy 72 hours after surgery. The other surgically treated patient ( 3) restarted anticoagulation therapy 6 days after surgery. Surgical Treatment One patient ( 1) was managed conservatively due to mild symptoms and stable imaging findings. The other 2 patients in our series underwent craniotomies, and surgical complications occurred in both. A right-sided craniotomy with evacuation was performed in 1 patient ( 2) who had an acute right SDH, causing a decreased level of consciousness and left hemiparesis (Fig. 1). This patient developed evidence of a perioperative ischemic stroke in the left occipital lobe of 371

3 R. R. Mayer et al. TABLE 1: Demographics of LVAD-treated patients requiring neurosurgical consultation No. Age at LVAD Placement (mos) Age at Complication (mos) Sex Reason for VAD Type of VAD Type of Anticoagulation F dilated cardiomyopathy EXCOR heparin F dilated cardiomyopathy EXCOR heparin M transposition of great vessels HeartMate II heparin, aspirin presumed embolic origin from the LVAD in the setting of withheld anticoagulation during neurosurgery. This patient also developed a pseudomeningocele that required further sur gical management for resolution. The other patient ( 3) who underwent a craniotomy developed herniation syndrome with a dilated left pupil and decreased responsiveness after an initial seizure and subsequently underwent a left hemicraniectomy (Fig. 2). The postoperative CT scan still showed residual midline shift as well as reaccumulation of blood in the subdural space. The patient was returned to the operating room for evacuation of the recurrent SDH (Table 3). Outcomes Patients were assessed at the last follow-up (286, 503, and 550 days) for neurological and cardiac outcomes. The patient who did not undergo a neurosurgical procedure ( 1) underwent a transplant and was discharged home but died 11 months posttransplantation of graft failure. Of the patients who underwent emergency neurosurgical intervention, 1 patient ( 2) was neurologically intact, received a heart transplant at 87 days after SDH evacuation, and remains stable at 19 months posttransplantation. The other patient ( 3) maintained a residual right hemiparesis from his initial neurological insult. This patient had an LVAD as a bridge to destination and was discharged from the hospital. He subsequently died of fungal sepsis 286 days after SDH evacuation. Both patients who underwent neurosurgical procedures remained stable with anticoagulation while on LVAD support (Table 4). Illustrative 2 This female patient developed dilated cardiomyopathy and subsequent heart failure shortly after birth. The patient underwent placement of an EXCOR pediatric VAD at 4 months of age. During the postoperative period, she was maintained on heparin anticoagulation for her VAD. At 1 month postoperation, the patient was noted to have decreased responsiveness and a left hemiparesis. A CT scan of the head demonstrated a right-sided SDH with 9 mm of midline shift (Fig. 1). The scan demonstrated components of acute and chronic bleeding. The patient underwent an emergency right-sided craniotomy with evacuation of the hematoma. Postoperative imaging demonstrated a left occipital ischemic stroke that was not present on prior imaging. Postoperatively, the patient developed a pseudomeningocele requiring dural repair and later revision; it slowly improved over time. At 87 days after SDH evacuation, she received a heart transplant, and the LVAD was discontinued. On last follow-up, approximately 1.5 years after neurosurgical intervention, the patient was meeting neurological milestones and was stable from a cardiac standpoint. Discussion Mechanical support as a bridge to heart transplantation improves survival in children with end-stage heart failure. 11,12 Extracorporeal membrane oxygenation remains the most common type of mechanical support used in the pediatric age group, especially for acute forms of heart failure. 8,12,21 However, ECMO nonpulsatile flow restricts patient mobility and presents a high incidence of hemorrhagic and infective complications when used for more than 2 weeks, and thus is not an effective bridge to transplantation. 17 The use of pulsatile, paracorporeal, closed-circuit VADs extends support time and influences management TABLE 2: Summary of clinical presentations of VAD-treated patients with neurosurgical complications No. Signs & Symptoms Neurological Complication 1 decreased interactive play intraparenchymal hemorrhage & infarction transformed into chronic subdural hygroma/hematoma 2 decreased responsiveness SDH 3 seizure SDH Fig Left: Preoperative brain CT scan without contrast showing a 10-mm-thick acute right-sided SDH with hyperacute findings and 8.2 mm of right-to-left midline shift. Right: Brain CT scan without contrast obtained at 4 months after surgery, demonstrating no acute intracranial pathology; however, there is the formation of a large subgaleal pseudomeningocele. 372 J Neurosurg: Pediatrics / Volume 10 / November 2012

4 Neurosurgical complications of LVADs in children TABLE 4: Outcome summary of all patients with neurological complications during VAD use No. Cardiac Outcome Neurological Outcome Follow-Up (days) 1 bridge to trans- died 503 plant, then heart failure 2 stable meeting neurological 550 milestones 3 fungemia of LVAD, sepsis rt hemiparesis, died 286 Fig A: Brain CT scan obtained preoperatively without contrast, demonstrating a thin acute left-sided SDH; however, there is 6.6 mm of left-to-right midline shift. B: Brain CT scan without contrast obtained immediately postoperatively, showing a reaccumulation of the extraaxial hematoma with interhemispheric extension and worsening midline shift (now measuring 15.6 mm). C: Brain CT scan without contrast obtained postoperatively after the second procedure to evacuate the reaccumulated subdural blood, showing resolution of the midline shift with stable subdural, intraparenchymal, and intraventricular hematoma. D: Brain CT scan without contrast obtained 8 months after surgery, just prior to death, demonstrating no acute intracranial pathology with ex vacuo changes related to the left lateral ventricle. of end-stage heart failure in the pediatric population. 1,7,23 Pulsatile pumping results in better tissue perfusion and an increased recruitment of the microcirculation of the brain, lungs, and kidneys. 2 In addition, by reversing endorgan dysfunction, pulsatile VADs improve the overall clinical condition and the likelihood of successful heart transplantation. 5,14,22,28 Continuous flow VADs (such as the HeartMate II) now provide an additional method of mechanical support prior to transplantation in the pediatric population. 20 Furthermore, the US FDA recently approved the EXCOR Pediatric System (Berlin Heart), TABLE 3: Surgical complications after craniotomy or craniectomy for ICH in 2 patients with LVADs No. Indication Neurosurgical Op Intraop Complications 2 rt SDH rt craniotomy lt occipital ischemic stroke 3 lt SDH lt hemicrani- none ectomy Postoperative Complications pseudomeningocele secondary herniation, recurrent lt SDH, death* * SDH required reoperation within the 24-hour postoperative period. J Neurosurg: Pediatrics / Volume 10 / November 2012 which was found to successfully bridge 90% of children to heart transplantation, a significant improvement when compared with the use of ECMO. 30 However, as our small series demonstrates, the use of VADs is not without serious neurological complications. To the best of our knowledge, this is the first study to describe the neurosurgical management of acute, severe neurological complications following VAD implantation. Our institutional experience, consistent with several recent studies, demonstrates that these complications represent an important and emerging group of complications in pediatric patients. 2,5,19 The overall incidence of ICH was 6.5% of the total cohort of 46 patients, with 2 of 3 patients presenting with ICH requiring operative treatment. We found that the rate of neurological complications and, in particular, hemorrhage was similar in children compared with adults (2.5% 10%). 16,18,20 In contrast to children, a large percentage of adult patients with LVADs have a history of stroke prior to implantation, a risk factor for later stroke recurrence. 18 The rate of mortality from mechanical circulatory support in adults increases from 61% in those without ICH to 92.3% in those with ICH; 20 however, the role of surgically evacuating ICH in these patients is not clear. Our study documents short- and long-term results of craniotomy/craniectomy for symptomatic ICH during LVAD placement in children. Each of the 2 children who were surgically treated at our institution had an ICH during LVAD use. Of the 2 patients who underwent craniotomy/ craniectomy, one patient ( 3) remained on LVAD and had the heparin anticoagulation temporarily halted, but not reversed, during the procedure. The other patient ( 2) remained on LVAD, but had the anticoagulation fully reversed for the procedure. There is no evidence-based approach to manage ICH in LVAD-treated patients. In our experience, the recommended approach begins with an immediate reversal of anticoagulation and antiplatelet therapy. The target goal is to obtain a full reversal of the prothrombin time and activated partial thromboplastin time and maintain the platelet count higher than /L; however, we recommend a modulation of these targets, depending on the extent of bleeding and type of VAD. As an example, the HeartMate II is designed with a biological surface derived from fibrin and does not require long-term anticoagulation (except aspirin); 25 therefore, we are less care- 373

5 R. R. Mayer et al. ful in regard to a full reversal of anticoagulation with the HeartMate II than we are with the EXCOR device. Infusions of fresh frozen plasma, cryoprecipitate, factor VII, protamine, platelets, desmopressin, and/or vitamin K are given, depending on the specific therapy the patient is receiving. Intraoperatively, these patients often require vigorous blood pressure support and fluid resuscitation. 10 Postoperatively, daily laboratory values should include lactate dehydrogenase and plasma hemoglobin to monitor for signs of intrapump thrombus formation and hemolysis. The LVAD cardiac output and pump parameters can be manipulated to decrease the probability of clot formation during this period of low or no anticoagulation by increasing the rate and ensuring full ejection. We recommend a consultation with the hematology service to optimize coagulation parameters in the postoperative period. In our series, both surgically treated patients restarted heparin anticoagulation therapy more than 72 hours after surgery. The decision to intervene surgically in these high-risk patients is difficult. Our results demonstrate that the risk of perioperative neurological complication is high, given the necessity to modify anticoagulation parameters during surgery, but good intermediate neurological outcomes are attainable. All 3 patients whom we treated had good intermediate neurological follow-up. While one patient who underwent surgical intervention died of fungemia approximately 9 months after surgery, the other patient who underwent craniotomy went on to receive a heart transplant and, from a cardiac and neurological standpoint, is doing well. Acceptable long-term outcomes depend not only on neurological recovery but also on a good cardiovascular prognosis. Future research will determine at which point the risk of hemorrhage is reduced enough to permit safe treatment with traditional anticoagulants and whether new approaches to anticoagulation might be suitable in the acute stroke and poststroke periods. 26,27 Conclusions Intracranial hemorrhage is a significant complication of the emerging therapy of LVADs in children with heart failure. The incidence of LVAD-associated ICH in children appears similar when compared with that in adults. Neurosurgical intervention may be considered for select patients with LVAD-associated ICH. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation include the following. Conception and design: Jea. Acquisition of data: Jea. Analysis and interpretation of data: Jea. Drafting the article: Jea, Mayer, Hwang. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Jea. Administrative/technical/material support: Jea. Study supervision: Jea. References 1. Adachi I, Fraser CD Jr: Mechanical circulatory support for infants and small children. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 14:38 44, Amodeo A, Brancaccio G, Michielon G, Filippelli S, Ricci Z, Morelli S, et al: Pneumatic pulsatile ventricular assist device as a bridge to heart transplantation in pediatric patients. Artif Organs 34: , Arabía FA, Tsau PH, Smith RG, Nolan PE, Paramesh V, Bose RK, et al: Pediatric bridge to heart transplantation: application of the Berlin Heart, Medos and Thoratec ventricular assist devices. J Heart Lung Transplant 25:16 21, Ashton RC Jr, Oz MC, Michler RE, Champsaur G, Catanese KA, Hsu DT, et al: Left ventricular assist device options in pediatric patients. 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