Abnormalities of brain imaging in patients after left ventricular assist device support following explantation

Brain atrophy in heart failure patients following left ventricular assist device implantation or heart transplantation

Advanced heart failure is associated with accelerated brain atrophy, largely related to chronic cerebral malperfusion. Both heart transplantation (HT) and left ventricular assist device (LVAD) implantation improve vital organ perfusion, but the comparative effect on brain atrophy remains unclear. Given the MR incompatibility of LVADs, we leveraged serial CT imaging in patients who underwent either HT or LVAD implantation. 58 patients were included in this single-center retrospective cohort (23 LVAD; 35 HT). LVAD patients experienced greater brain atrophy (median: 7.1 mL/year; IQR: 0.9-15.7) than transplant patients (median: 0.4 mL/year; IQR: -6.7-13.9), but this difference was non-significant (p=0.09). Temporal atrophy (expansion of the Sylvian fissure) was greater in LVAD patients (median: 0.91 mm/year; IQR: 0.14-2.27) than HT patients (median: 0.10 mm/year; IQR: 0.02-0.55), p=0.005. These observations reveal a need for future work to prospectively quantify brain atrophy after LVAD implantation and HT, while comparing with that of advanced heart failure.

The multifaceted role of neuropsychology in pediatric solid organ transplant: preliminary guidelines and strategies for clinical practice

The incidence of pediatric solid organ transplantation (SOT) has increased in recent decades due to medical and surgical advances as well as improvements in organ procurement. Survival rates for pediatric kidney, liver, and heart transplantation are above 85% but patients continue to experience complex healthcare needs over their lifetime. Long-term developmental and neuropsychological sequelae are becoming increasingly recognized in this population, although preliminary work is limited and deserves further attention. Neuropsychological weaknesses are often present prior to transplantation and may be related to underlying congenital conditions as well as downstream impact of the indicating organ dysfunction on the central nervous system. Neuropsychological difficulties pose risk for functional complications, including disruption to adaptive skill development, social-emotional functioning, quality of life, and transition to adulthood. The impact of cognitive dysfunction on health management activities (e.g., medication adherence, medical decision-making) is also an important consideration given these patients' lifelong medical needs. The primary aim of this paper is to provide preliminary guidelines and clinical strategies for assessment of neuropsychological outcomes across SOT populations for pediatric neuropsychologists and the multidisciplinary medical team, including detailing unique and shared etiologies and risk factors for impairment across organ types, and functional implications. Recommendations for clinical neuropsychological monitoring as well as multidisciplinary collaboration within pediatric SOT teams are also provided.

When Atrial Fibrillation Meets Cerebral Amyloid Angiopathy: Current Evidence and Strategies

Non-valvular atrial fibrillation (AF) and cerebral amyloid angiopathy (CAA) are two common diseases in elderly populations. Despite the effectiveness of oral anticoagulant therapy in cardioembolic stroke prevention, intracranial hemorrhage represents the most serious complication of these therapies. Cerebral amyloid angiopathy is one of the main risk factors for spontaneous intracranial bleeding, and this risk is highly increased by age and concomitant antithrombotic therapies. Cerebral amyloid angiopathy can be silent for years and then manifest with clinical features simulating TIA (TIA-mimics) or stroke in AF patients, pushing clinicians to rapidly start VKAs or DOACs, thus increasing the risk of intracranial bleeding if the diagnosis of CAA was unknown. Because the cerebral amyloid angiopathy is easily diagnosed with non-contrast MRI, suspecting the disease can avoid catastrophic complications. In this review, we will provide physicians managing anticoagulant therapies with key tips to familiarize themselves with cerebral amyloid angiopathy, with a focus on the possible clinical presentations and on the diagnostic criteria.

Stroke and Mechanical Circulatory Support in Adults

PURPOSE OF THE REVIEW

Short-term and durable mechanical circulatory support (MCS) devices represent life-saving interventions for patients with cardiogenic shock and end-stage heart failure. This review will cover the epidemiology, risk factors, and treatment of stroke in this patient population.

RECENT FINDINGS

Short-term devices such as intra-aortic balloon pump, Impella, TandemHeart, and Venoatrial Extracorporal Membrane Oxygenation, as well as durable continuous-flow left ventricular assist devices (LVADs), improve cardiac output and blood flow to the vital organs. However, MCS use is associated with high rates of complications, including ischemic and hemorrhagic strokes which carry a high risk for death and disability. Improvements in MCS technology have reduced but not eliminated the risk of stroke. Mitigation strategies focus on careful management of anti-thrombotic therapies. While data on therapeutic options for stroke are limited, several case series reported favorable outcomes with thrombectomy for ischemic stroke patients with large vessel occlusions, as well as with reversal of anticoagulation for those with hemorrhagic stroke. Stroke in patients treated with MCS is associated with high morbidity and mortality. Preventive strategies are targeted based on the specific form of MCS. Improvements in the design of the newest generation device have reduced the risk of ischemic stroke, though hemorrhagic stroke remains a serious complication.

Pulsatility and flow patterns across macro- and microcirculatory arteries of continuous-flow left ventricular assist device patients

BACKGROUND

Reduced arterial pulsatility in continuous-flow left ventricular assist devices (CF-LVAD) patients has been implicated in clinical complications. Consequently, recent improvements in clinical outcomes have been attributed to the "artificial pulse" technology inherent to the HeartMate3 (HM3) LVAD. However, the effect of the "artificial pulse" on arterial flow, transmission of pulsatility into the microcirculation and its association with LVAD pump parameters is not known.

METHODS

The local flow oscillation (pulsatility index, PI) of common carotid arteries (CCAs), middle cerebral arteries (MCAs) and central retinal arteries (CRAs-representing the microcirculation) were quantified by 2D-aligned, angle-corrected Doppler ultrasound in 148 participants: healthy controls, n = 32; heart failure (HF), n = 43; HeartMate II (HMII), n = 32; HM3, n = 41.

RESULTS

In HM3 patients, 2D-Doppler PI in beats with "artificial pulse" and beats with "continuous-flow" was similar to that of HMII patients across the macro- and microcirculation. Additionally, peak systolic velocity did not differ between HM3 and HMII patients. Transmission of PI into the microcirculation was higher in both HM3 (during the beats with "artificial pulse") and in HMII patients compared with HF patients. LVAD pump speed was inversely associated with microvascular PI in HMII and HM3 (HMII, r2 = 0.51, p < 0.0001; HM3 "continuous-flow," r2 = 0.32, p = 0.0009; HM3 "artificial pulse," r2 = 0.23, p = 0.007), while LVAD pump PI was only associated with microcirculatory PI in HMII patients.

CONCLUSIONS

The "artificial pulse" of the HM3 is detectable in the macro- and microcirculation but without creating a significant alteration in PI compared with HMII patients. Increased transmission of pulsatility and the association between pump speed and PI in the microcirculation indicate that the future clinical care of HM3 patients may involve individualized pump settings according to the microcirculatory PI in specific end-organs.

Neurologic Complications in Patients With Left Ventricular Assist Devices

Left ventricular assist device (LVAD) use has revolutionised the care of patients with advanced heart failure, allowing more patients to survive until heart transplantation and providing improved quality for patients unable to undergo transplantation. Despite these benefits, improvements in device technology, and better clinical care and experience, LVADs are associated with neurologic complications. This review provides information on the incidence, risk factors, and management of neurologic complications among LVAD patients. Although scant guidelines exist for the evaluation and management of neurologic complications in LVAD patients, a high index of suspicion can prompt early detection of neurologic complications which may improve overall neurologic outcomes. A better understanding of the implications of continuous circulatory flow on systemic and cerebral vasculature is necessary to reduce the common occurrence of neurologic complications in this population.

Implications of Causes of Intracranial Hemorrhage During Left Ventricular Assist Device Support

BACKGROUND

Intracranial hemorrhage (ICH) is a frequent complication in patients with an implanted left ventricular assist device (LVAD) for advanced heart failure. Bloodstream infection is known to be associated with ICH in patients with LVAD, but its effects on ICH-associated mortality are unknown. We compared characteristics and mortality of infection-associated, traumatic, and spontaneous hemorrhages.

METHODS

Patients in an LVAD registry at a tertiary care center were reviewed for this cohort study. ICH included intraparenchymal hemorrhage, subarachnoid hemorrhage, and subdural hemorrhage. Hemorrhages were categorized into infectious, traumatic, and spontaneous by the presence or absence of concurrent device-associated infection or antecedent trauma.

RESULTS

Of 683 patients with an LVAD, 73 experienced ICH (10.7%). Intraparenchymal hemorrhage was the most prevalent (72%), followed by subarachnoid hemorrhage (27%) and subdural hemorrhage (23%), with multiple concurrent hemorrhage subtypes in 16 patients (22%). Median time from implantation to ICH was shorter in spontaneous ICH than in infection-associated ICH (100 days vs. 252 days, p = 0.048). The prevalence of the different subtypes of ICH were similar between spontaneous and infection-associated ICH, and no differences were seen in mortality between the different causes of ICH.

CONCLUSIONS

Although spontaneous ICH occurred earlier after LVAD implantation than infection-associated ICH, no difference in mortality was seen between the different causes of ICH.

Surgical left atrial appendage occlusion in patients with left ventricular assist device

BACKGROUND

Thromboembolic (TE) events are among the most common and devastating adverse events in patients with continuous-flow left ventricular assist device (cf-LVAD). Given the high burden of AF among cf-LVAD patients, we sought to evaluate the effect of concomitant surgical LAAO in patients receiving cf-LVAD.

METHODS

A systematic search using electronic databases was performed using the keywords: "left atrial appendage occlusion" and "left ventricular assist device." Statistical analysis was performed using meta-package for R version 4.0 and Rstudio version 1.2. Mantel-Haenszel risk ratio (RR) random-effects model was used to summarize data between two groups. The primary outcomes included: (a) stroke; (b) LVAD pump thrombosis; (c) all-cause mortality RESULTS: : Three studies with a total of 305 patients (LAAO=68 and No-LAAO=237) were included in the analysis. HeartMate II (39%) and Heartware (27.5%) were the two most common cf-LVADs utilized, while only 5% received HeartMate III. At a mean follow up of 1.47 years, LAAO group had a lower risk of stroke (8.8% vs 15.2%, RR 0.64; 95% CI 0.28 - 1.49), LVAD pump thrombosis (1.5% vs 3.8%, RR 0.28; 95% CI 0.05 - 1.55) and all-cause mortality (5.9% vs 20.2%, RR 0.69; 95% CI 0.19 - 2.52) when compared with no-LAAO group, but the difference did not reach statistical significance.

CONCLUSION

Concomitant surgical LAAO at the time of cf-LVAD implantation demonstrated a trend towards positive outcomes and was not associated with adverse outcomes during the follow-up period, though the results were not statistically significant This article is protected by copyright. All rights reserved.

Long-Term Neurocognitive Outcome in Patients With Continuous Flow Left Ventricular Assist Device

OBJECTIVES

The authors sought to examine the long-term cognitive outcome of patients with continuous flow left ventricular assist device (CF-LVAD).

BACKGROUND

Data on long-term neurocognitive outcome in LVAD are limited. We examined the neurocognitive outcome of patients who received a CF-LVAD as destination therapy.

METHODS

Patients with HeartWare (HVAD) and HeartMate II who were enrolled in the ENDURANCE and ENDURANCE Supplemental trials were eligible. Cognition was evaluated with neuropsychological testing preoperatively and at 6, 12, and 24 months after implantation. General linear models identified demographic, disease, and treatment factors that predicted decline on each neurocognitive measure.

RESULTS

Of 668 patients who completed baseline testing and at least 1 follow-up evaluation, 552 were impaired at baseline on at least 1 cognitive measure. At each follow-up, approximately 23% of tested patients declined and 20% improved relative to baseline on at least 1 cognitive measure. Of those who were intact at baseline, only 10%-12% declined in delayed memory and 11%-16% declined in executive function at all 3 follow-ups. For patients impaired at baseline, delayed memory decline was associated with the HVAD device and male sex, whereas executive function decline was associated with the HVAD device and stroke during CF-LVAD support. For patients intact at baseline, male sex and history of hypertension were associated with decline in immediate memory and executive function, respectively.

CONCLUSIONS

Neurocognitive function remained stable or improved for most patients (∼80%) with CF-LVAD at 6, 12, and 24 months after implantation. Male sex, hypertension, HVAD, and stroke were associated with cognitive decline.

Cerebral Microvascular Injury in Patients with Left Ventricular Assist Device: a Neuropathological Study

Strokes are common among patients with left ventricular devices (LVAD). We hypothesize that there is ongoing cerebral microvascular injury with LVAD support and aim to describe this among LVAD-implanted patients through post-mortem neuropathologic evaluation. We identified and reviewed medical records of LVAD patients who underwent brain autopsy between January 2006 and December 2019 at a tertiary center. Cerebral injury was defined as both gross and microscopic injuries within the intracranial space including cerebral infarct (CI), hypoxic-ischemic brain injury (HIBI), intracranial hemorrhage (ICH), and cerebral microvascular injury. Cerebral microvascular injury was defined as microscopic brain intraparenchymal or perivascular hemorrhage, perivascular hemosiderin deposition, and perivascular inflammation. Twenty-one patients (median age = 57 years, 67% male) had autopsy after LVAD support (median LVAD support = 51 days). The median time from death to autopsy was 19 h. All 21 patients had cerebral injuries and 19 (90%) patients had cerebral microvascular injuries. Fourteen patients (78%) harbored more than one type of cerebral injury. On gross examination, 8 patients (38%) had CI, and 6 patients (29%) had ICH. On microscopic exam, 12 patients (57%) had microscopic intraparenchymal hemorrhage, 3 patients (14%) had perivascular hemorrhage, 11 patients (43%) had perivascular hemosiderin deposition, 5 patients (24%) had meningeal hemorrhage, 13 patients had chronic perivascular inflammation (62%), and 2 patients had diffuse HIBI (10%). Among patients with LVAD, there is a high prevalence of subclinical microvascular injuries and cerebral microbleeds (CMBs), which may provide some insights to the cause of frequent cerebral injury in LVAD population.

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.

Cerebrovascular Disease and Cognitive Outcome in Patients with Cardiac Disease

The pace of understanding cognitive decline and dementia has rapidly accelerated over the past decade, with constantly evolving insights into the vascular contributions to cognitive impairment and dementia (VCID). Notably, more overlap has been discovered in the pathophysiology between what was previously understood to be Alzheimer's disease and VCID, leading to a heightened emphasis on disease prevention through early and aggressive control of vascular risk factors. One particularly vulnerable population may be those with cardiac disease, as they are at risk for cerebrovascular disease, which itself can lead to dementia, and increasing evidence supports cognitive impairment in disease processes such as heart failure and atrial fibrillation, independent of ischemic stroke, suggesting other potential mechanisms. In this article, we review the evidence supporting the relationship between cardiac disease, cerebrovascular disease, and cognitive decline and discuss the ongoing and future research efforts aimed at defining the important relationship between these entities.

A Comprehensive Review of Risk Factor, Mechanism, and Management of Left Ventricular Assist Device-Associated Stroke

The use of left ventricular assist devices (LVADs) has been increasing in the last decade, along with the number of patients with advanced heart failure refractory to medical therapy. Ischemic stroke and intracranial hemorrhage remain the leading causes of morbidity and mortality in LVAD patients. Despite the common occurrence and the significant outcome impact, underlying mechanisms and management strategies of stroke in LVAD patients are controversial. In this article, we review our current knowledge on pathophysiology and risk factors of LVAD-associated stroke, outline the diagnostic approach, and discuss treatment strategies.

Management of Intracranial Hemorrhage in Patients with a Left Ventricular Assist Device: A Systematic Review and Meta-Analysis

BACKGROUND

Intracranial hemorrhage (ICH) has been reported to occur in up to 23% of patients with left ventricular assist devices (LVADs). Currently, limited data exists to guide neurosurgical management strategies to optimize outcomes in patients with an LVAD who develop ICH.

METHODS

A systematic review and meta-analysis of the literature was performed to evaluate the mortality rate in these patients following medical and/or surgical management and to evaluate antithrombotic reversal and resumption strategies after hemorrhage.

RESULTS

17 studies reporting on 3869 LVAD patients and 545 intracranial hemorrhages spanning investigative periods from 1996 to 2019 were included. The rate of ICH in LVAD patients was 10.6% (411/3869) with 58.6% (231/394) being intraparenchymal hemorrhage (IPH), 23.6% (93/394) subarachnoid hemorrhage (SAH), and 15.5% (61/394) subdural hemorrhage (SDH). Total mortality rates for surgical management 65.6% (40/61) differed from medical management at 45.2% (109/241). There was an increased relative risk of mortality (RR=1.45, 95% CI: 1.10-1.91, p = 0.01) for ICH patients undergoing surgical intervention. The hemorrhage subtype most frequently managed with anticoagulation reversal was IPH 81.8% (63/77), followed by SDH 52.2% (12/23), and SAH 39.1% (18/46). Mean number of days until antithrombotic resumption ranged from 6 to 10.5 days.

CONCLUSION

Outcomes remain poor, specifically for those undergoing surgery. As experience with this population increases, prospective studies are warranted to contribute to management and prognostication .

Clinically Silent Brain Injury and Perioperative Neurological Events in Patients With Left Ventricular Assist Device: A Brain Autopsy Study

Current studies underestimate the prevalence of brain injury in patients with left ventricular assist devices (LVADs), as CT scans are not sensitive in detecting cerebral ischemia. Using postmortem neuropathological evaluation, we sought to characterize the types and risk factors of brain injury in LVAD patients. We reviewed 24 LVAD patients who underwent brain autopsy with gross and microscopic examinations from 1993 through 2019 at a single tertiary center. Patients who expired less than 7 days after implantation or who underwent explantation more than 7 days before death were excluded. Our study demonstrated that all LVAD nonsurvivors developed brain injury. The most common brain injury was hemorrhage (71%), followed by infarct (42%) and hypoxic ischemic brain injury (HIBI) (33%), and 10 patients (42%) presented with more than 1 brain injury. Cerebral microbleeds (CMBs) and intracranial hemorrhage were present in 33% and 42%, respectively. In those with intracranial hemorrhage, subarachnoid hemorrhage (25%) and intracerebral hemorrhage (25%) were more common than subdural hematoma (4%). Intracranial hemorrhage was associated with driveline infection (P = 0.047), and HIBI was associated with prior history of chronic obstructive pulmonary disease (P = 0.037). Fourteen (60%) had clinically silent brain injury with 65% of hemorrhages and 70% of infarcts being silent. However, the impact of silent brain injury on neurologic outcome and mortality remains unclear. Standardized neurologic monitoring and surveillance are recommended to better detect these clinically silent brain injury.