Sulcus subarachnoid hemorrhage is a common stroke subtype in patients with implanted left ventricular assist devices

Intracranial Mycotic Aneurysm after Left Ventricular Assist Device Implantation Treated with Trans-arterial Embolization via the Brachial Artery: A Case Report

Implantation of left ventricular assist device (LVAD) is widely performed in patients with end-stage chronic heart failure. Infection and stroke are major complications after LVAD implantation. However, the incidence of intracranial mycotic aneurysm after LVAD implantation is rare, and with no standard of care. In this study, we describe a case of an intracranial mycotic aneurysm after LVAD implantation that was successfully treated with trans-arterial embolization (TAE) with N-butyl 2-cyanoacrylate (NBCA) via the brachial artery. A 49-year-old man with a history of implantation of LVAD for ischemic cardiomyopathy was admitted to our institution. He had infectious endocarditis and was administered systemic antibiotics. At 3 weeks after admission, intracranial mycotic aneurysm of the left posterior parietal artery was detected during a diagnostic examination for asymptomatic intracranial hemorrhage. Anticoagulant therapy was administered to prevent thromboembolic complications of LVAD implantation. Under local anesthesia, TAE with NBCA was performed via the brachial artery because of the tortuous anatomy of the origin of the innominate artery and implant of the aortic arch. The aneurysm was completely obliterated. The patient was discharged without neurological deficits. TAE using NBCA could be an effective modality for the treatment of intracranial mycotic aneurysm after LVAD implantation.

How Are We Monitoring Brain Injuries in Patients With Left Ventricular Assist Device? A Systematic Review of Literature

Despite the common occurrence of brain injury in patients with left ventricular assist device (LVAD), optimal neuromonitoring methods are unknown. A systematic review of PubMed and six electronic databases from inception was conducted until June 5, 2019. Studies reporting methods of neuromonitoring while on LVAD were extracted. Of 5,190 records screened, 37 studies met the inclusion criteria. The neuromonitoring methods include Transcranial Doppler ultrasound for emboli monitoring (TCD-e) (n = 13) and cerebral autoregulation (n = 3), computed tomography and magnetic resonance imaging (n = 9), serum biomarkers (n = 7), carotid ultrasound (n = 3), and near-infrared spectroscopy (n = 2). Of 421 patients with TCD-e, thromboembolic events (TEs) were reported in 79 patients (20%) and microembolic signals (MES) were detected in 105 patients (27%). Ischemic stroke was more prevalent in patients with MES compared to patients without MES (43% vs.13%, p < 0.001). Carotid ultrasound for assessing carotid stenosis was unreliable after LVAD implantation. Elevated lactate dehydrogenase (LDH) levels were associated with TEs. Significant heterogeneity exists in timing, frequency, and types of neuromonitoring tools. TCD-e and serial LDH levels appeared to have potential for assessing the risk of ischemic stroke. Future prospective research incorporating protocolized TCD-e and LDH may assist in monitoring adverse events in patients with LVAD.

Acute Response of Human Aortic Endothelial Cells to Loss of Pulsatility as Seen during Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) results in short-term (3-5 h) exposure to flow with diminished pulsatility often referred to as "continuous flow". It is unclear if short-term exposure to continuous flow influences endothelial function, particularly, changes in levels of pro-inflammatory and pro-angiogenic cytokines. In this study, we used the endothelial cell culture model (ECCM) to evaluate if short-term (≤5 h) reduction in pulsatility alters levels of pro-inflammatory/pro-angiogenic cytokine levels. Human aortic endothelial cells (HAECs) cultured within the ECCM provide a simple model to evaluate endothelial cell function in the absence of confounding factors. HAECs were maintained under normal pulsatile flow for 24 h and then subjected to continuous flow (diminished pulsatile pressure and flow) as observed during CPB for 5 h. The ECCM replicated pulsatility and flow morphologies associated with normal hemodynamic status and CPB as seen with clinically used roller pumps. Levels of angiopoietin-2 (ANG-2), vascular endothelial growth factor-A (VEGF-A), and hepatocyte growth factor were lower in the continuous flow group in comparison to the pulsatile flow group whereas the levels of endothelin-1 (ET-1), granulocyte colony stimulating factor, interleukin-8 (IL-8) and placental growth factor were higher in the continuous flow group in comparison to the pulsatile flow group. Immunolabelling of HAECs subjected to continuous flow showed a decrease in expression of ANG-2 and VEGF-A surface receptors, tyrosine protein kinase-2 and Fms-related receptor tyrosine kinase-1, respectively. Given that the 5 h exposure to continuous flow is insufficient for transcriptional regulation, it is likely that pro-inflammatory/pro-angiogenic signaling observed was due to signaling molecules stored in Weible-Palade bodies (ET-1, IL-8, ANG-2) and via HAEC binding/uptake of soluble factors in media. These results suggest that even short-term exposure to continuous flow can potentially activate pro-inflammatory/pro-angiogenic signaling in cultured HAECs and pulsatile flow may be a successful strategy in reducing the undesirable sequalae following continuous flow CPB.

Mechanical thrombectomy in acute ischemic stroke patients with left ventricular assist device

OBJECTIVES

As the number of patients with left ventricular assist device (LVAD) implantation has been increasing, treatment of LVAD-related ischemic stroke is becoming a critical issue. We sought to clarify the features of mechanical thrombectomy in LVAD-related stroke with large vessel occlusion.

METHODS

In a multi-center, retrospective case-control study, we compared 20 LVAD-related strokes with 33 non-LVAD strokes, all of which had large vessel occlusion in the anterior circulation treated with mechanical thrombectomy. A comparative histopathological examination of the retrieved thrombi was also performed.

RESULTS

Successful reperfusion was achieved in 75% of the LVAD-related strokes. The time from onset to reperfusion was similar to that of non-LVAD strokes, but the total number of device passes required for reperfusion (median, 2.5 versus 1, P = 0.01) and the incidences of post-procedural parenchymal and subarachnoid hemorrhage (25% versus 3%, P = 0.02 and 55% versus 15%, P = 0.01, respectively) were higher in LVAD-related strokes. Symptomatic intracranial hemorrhage occurred in 4 patients (20%) with LVAD-related strokes. The histopathological analysis revealed that the ratio of erythrocyte components was significantly lower in thrombi retrieved from patients with LVAD-related stroke than in those with non-LVAD stroke (19 ± 6% versus 41 ± 17%, P = 0.01).

CONCLUSIONS

Mechanical thrombectomy is feasible in patients with LVAD-related stroke. However, repetitive device passes are needed to achieve successful reperfusion mainly because of the structurally organized thrombi, and the higher risk of hemorrhagic complications should be considered, while offering this therapeutic alternative.

Cerebrovascular Events After Continuous-Flow Left Ventricular Assist Devices

BACKGROUND

Cerebrovascular events (CVE) are among the most common and serious complications after implantation of continuous-flow left ventricular assist devices (CF-LVAD). We studied the incidence, subtypes, anatomical distribution, and pre- and post-implantation risk factors of CVEs as well as the effect of CVEs on outcomes after CF-LVAD implantation at our institution.

METHODS

Retrospective analysis of clinical and neuroimaging data of 372 patients with CF-LVAD between May 2005 and December 2013 using standard statistical methods.

RESULTS

CVEs occurred in 71 patients (19%), consisting of 35 ischemic (49%), 26 hemorrhagic (37%), and 10 ischemic+hemorrhagic (14%) events. History of coronary artery disease and female gender was associated with higher odds of ischemic CVE (OR 2.84 and 2.5, respectively), and diabetes mellitus was associated with higher odds of hemorrhagic CVE (OR 3.12). While we found a higher rate of ischemic CVEs in patients not taking any antithrombotic medications, no difference was found between patients with ischemic and hemorrhagic CVEs. Occurrence of CVEs was associated with increased mortality (HR 1.62). Heart transplantation was associated with improved survival (HR 0.02). In patients without heart transplantation, occurrence of CVE was associated with decreased survival.

CONCLUSIONS

LVADs are associated with high rates of CVE, increased mortality, and lower rates of heart transplantation. Further investigations to identify the optimal primary and secondary stroke prevention measures in post-LVAD patients are warranted.

Evaluation of flow-modulation approaches in ventricular assist devices using an in-vitro endothelial cell culture model

BACKGROUND

Continuous-flow ventricular assist devices (CF-VADs) produce non-physiologic flow with diminished pulsatility, which is a major risk factor for development of adverse events, including gastrointestinal (GI) bleeding and arteriovenous malformations (AVMs). Introduction of artificial pulsatility by modulating CF-VAD flow has been suggested as a potential solution. However, the levels of pulsatility and frequency of CF-VAD modulation necessary to prevent adverse events are currently unknown and need to be evaluated.

METHODS

The purpose of this study was to use human aortic endothelial cells (HAECs) cultured within an endothelial cell culture model (ECCM) to: (i) identify and validate biomarkers to determine the effects of pulsatility; and (ii) conclude whether introduction of artificial pulsatility using flow-modulation approaches can mitigate changes in endothelial cells seen with diminished pulsatile flow. Nuclear factor erythroid 2-related factor 2 (Nrf-2)-regulated anti-oxidant genes and proteins and the endothelial nitric oxide synthase/endothelin-1 (eNOS/ET-1) signaling pathway are known to be differentially regulated in response to changes in pulsatility.

RESULTS

Comparison of HAECs cultured within the ECCM (normal pulsatile vs CF-VAD) with aortic wall samples from patients (normal pulsatile [n = 5] vs CF-VADs [n = 5]) confirmed that both the Nrf-2-activated anti-oxidant response and eNOS/ET-1 signaling pathways were differentially regulated in response to diminished pulsatility. Evaluation of 2 specific CF-VAD flow-modulation protocols to introduce artificial pulsatility, synchronous (SYN, 80 cycles/min, pulse pressure 20 mm Hg) and asynchronous (ASYN, 40 cycles/min, pulse pressure 45 mm Hg), suggested that both increased expression of Nrf-2-regulated anti-oxidant genes and proteins along with changes in levels of eNOS and ET-1 can potentially be minimized with ASYN and, to a lesser extent, with SYN.

CONCLUSIONS

HAECs cultured within the ECCM can be used as an accurate model of large vessels in patients to identify biomarkers and select appropriate flow-modulation protocols. Pressure amplitude may have a greater effect in normalizing anti-oxidant response compared with frequency of modulation.

Neurosurgical Management and Outcomes of Cerebrovascular Disease in Pediatric Patients with Heart Disease

Antithrombotic treatment has substantial risks, even in pediatric patients. We retrospectively evaluated the management and outcomes of consecutive pediatric patients who underwent neurosurgical treatment for cerebrovascular disease with cardiovascular disease between 1998 and 2017. Patients were divided into patients with comorbid cardiovascular disease (group I); and patients with cardiovascular disease as a primary disease of intracranial complication, without (group IIa) or with (group IIb) extracorporeal circulations. Postoperative resumption of antithrombotic agents was generally initiated within 48 h. Our study included 26 patients; five were categorized as group I, 15 as group IIa, and six as group IIb. All intracranial diseases in groups IIa and IIb were exclusively hemorrhagic. Preoperative anticoagulation therapy was used in one patient (20%) in group I, 13 patients (86.7%) in group IIa, and six patients (100%) in group IIb. Postoperative intracranial hemorrhagic events were observed in one patient (20%) in group I, three patients (20%) in group IIa, and four patients (66.7%) in group IIb. Re-operations were conducted in two (13.3%) and three patients (50%) in groups IIa and IIb, respectively. Death occurred in five (33.3%) and four patients (66.7%) in groups IIa and IIb, respectively. The remaining two patients in group IIb returned to candidate status for implantation. Emergent surgery for patients with intracranial hemorrhage associated with cardiovascular disease has a high risk of postoperative hemorrhagic events and high rate of re-operations with poor vital outcomes, especially in patients with extracorporeal circulations. We should consider maximum neurosurgical treatment achievable with optimal management of antithrombotic treatment.

One-year prognosis of non-traumatic cortical subarachnoid haemorrhage: A prospective series of 34 patients

INTRODUCTION

Cortical subarachnoid haemorrhage (cSAH) has multiple aetiologies. No prospective study has reported the long-term progression of the condition. The objective of this study is to describe the clinical and aetiological characteristics of patients with cSAH and to gain insight into prognosis.

METHODS

We performed a prospective, observational, multi-centre study. Data on clinical and radiological variables were collected; during a one-year follow-up period, we recorded data on mortality, dependence, rebleeding, and the appearance of dementia.

RESULTS

The study included 34 patients (mean age, 68.3 years; range, 27-89). The most frequent symptoms were headache and focal neurological deficits, which were frequently transient and recurrent. CT scans returned pathological findings in 28 patients (85%). Brain MRI scans were performed in 30 patients (88%), revealing acute ischaemia in 10 (29%), old haemorrhage in 7 (21%), and superficial siderosis in 2 (6%). Aetiology was identified in 26 patients (76.5%): causes were cerebral amyloid angiopathy in 8, ischaemic stroke in 5, vasculitis in 4, reversible posterior encephalopathy in 2, venous thrombosis in 2, reversible cerebral vasoconstriction syndrome in 2, carotid occlusion in 1, Marfan syndrome in 1, and meningeal carcinomatosis in 1. Three patients died during follow-up (2 due to causes related to the cause of cSAH). Three patients developed dementia, 3 had lobar haemorrhages, and one had a second cSAH.

CONCLUSIONS

The most frequent causes of cSAH in our series were cerebral amyloid angiopathy, ischaemic stroke, and vasculitis. This type of haemorrhage has a worse prognosis than other non-aneurysmal cSAH. There are numerous possible causes, and prognosis depends on the aetiology. In elderly patients, intracranial haemorrhage is frequently associated with cognitive impairment.

The pseudo-SAH sign: an imaging pitfall in postmortem computed tomography

Postmortem computed tomography (PMCT) of the brain has an important role in detection of subarachnoid hemorrhage (SAH), which has a high mortality rate. However, a phenomenon known as "pseudo-SAH," or high-attenuation areas along the cisterns mimicking SAH, may be seen on CT. The aim of this study was to evaluate the diagnostic accuracy of brain PMCT for SAH and to identify the characteristics of pseudo-SAH. Findings on PMCT (sulcal effacement, asymmetry, maximum thickness of SAH signs, presence of acute/subacute intraventricular/intraparenchymal hemorrhage) and clinical history (left ventricular assist device [LVAD] implantation, anticoagulation therapy/coagulation disorder, global ischemia) were compared between subjects with true SAH and those with pseudo-SAH. Twenty eight of 128 enrolled subjects had positive signs of SAH on PMCT, 20 (71.4%) had SAH on autopsy, and 8 (28.6%) did not. The sensitivity, specificity, positive predictive value, and negative predictive value of SAH signs seen on PMCT were 95.2, 94.6, 71.4, and 99.3%, respectively. Asymmetry of SAH signs and acute/subacute intraventricular and intraparenchymal hemorrhage were significantly more common in true SAH cases than in pseudo-SAH cases. The maximum thickness of SAH signs was significantly greater in true SAH cases. A history of LVAD implantation, anticoagulation therapy, and/or a coagulation disorder were more common in true SAH cases but not significantly so. A history of global ischemia was significantly more common in pseudo-SAH cases. If signs of SAH are observed on PMCT, it is important to look for other signs on PMCT and carefully review the clinical history to avoid a diagnostic error.