Prevalence of Cerebral Microbleeds in Patients With Continuous-Flow Left Ventricular Assist Devices

Early stroke after left ventricular assist device implantation: role of right heart failure

Background

Both stroke and right heart failure (RHF) are common and serious complications after left ventricular assist device (LVAD) implantation. The objective of this study was to evaluate relation between stroke and RHF early after LVAD implantation.

Methods

This is a retrospective observational cohort study. From January 2012 to December 2020, patients who underwent LVAD implantation in a single-center were enrolled. Patients with a non-dischargeable LVAD or without follow-up data were excluded. Early stroke was defined as a stroke event within 6 months after implantation. Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) definition was used for the diagnosis of RHF.

Results

A total of 70 patients underwent LVAD implantation. Sixty-seven patients (95.7%) were successfully discharged and 16 patients (22.9%) died during follow-up. 14 patients (20.0%) experienced a stroke within 6 months after implantation, and 0.28 stroke events per patient-year occurred during follow-up. Postoperative RHF was more common in the stroke group (64.3% vs. 23.2%, P=0.008) and the median time from implantation to RHF was 1 day. In the Cox multivariable analysis, postoperative RHF [hazard ratio (HR): 5.063; 95% confidence interval (CI): 1.682-15.245; P=0.004], and cerebral perfusion pressure (CPP) on postoperative day (POD) 1 (HR: 0.923; 95% CI: 0.858-0.992; P=0.030) were independent predictors for early stroke. A CPP of 62 mmHg (sensitivity, 71.4%; specificity, 59.3%) was the cutoff value for early stroke according to the receiver operating characteristic (ROC) analysis.

Conclusions

RHF after LVAD implantation may be a risk factor for early stroke. Prevention and management of postoperative RHF with adequate CPP could prevent early stroke after LVAD implantation.

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.

Mechanical circulatory support for adults in Japan: A 10-year perspective

Globalization in Asia and consequent strengthening of healthcare economic factors in tandem with an increasing heart failure (HF) population have enhanced potential for development and progress in the fields of HF medicine and mechanical circulatory support (MCS). In Japan, there are unique opportunities to investigate the outcome of acute and chronic MCS and a national registry for percutaneous and implantable left ventricular assist device (LVAD) including Impella pumps has been established. A Peripheral extracorporeal membrane oxygenation (ECMO) for acute MCS has been used in more than 7000 patients annually and Impella usage in more than 4000 patients over the past 4 years was noted. Recently, a novel centrifugal pump with hydrodynamically levitated impeller was developed and approved for mid-term extracorporeal circulatory support. In terms of chronic MCS more than 1200 continuous flow LVADs have been implanted during the past decade, and 2-year survival rate after primary LVAD implantation is 91%. Because of donor organ shortage, more than 70% of heart transplant recipients required LVAD support for more than 3 years and prevention and treatment of complications during long-term LVAD support have become important. Five important topics including hemocompatibility-related complications, LVAD infections, aortic valve insufficiency, right ventricular failure and cardiac recovery during LVAD support are discussed in this review for improving clinical outcomes. Findings from Japan will continue to provide useful information regarding MCS for the Asia-Pacific region and beyond.

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.

Effect of Diabetes Mellitus on Outcomes in Patients With Left Ventricular Assist Device - Analysis of Data From a Japanese National Database

BACKGROUND

The objective of this study is to investigate the effect of preoperative diabetes on all-cause mortality and major postoperative complications among patients with continuous-flow left ventricular assist device (LVAD) by using data from a national database.

METHODS AND RESULTS

The 545 study patients who underwent primary HeartMateII implantation between 2013 and 2019 were divided into 2 groups according to their diabetes mellitus (DM) status; patients with DM (n=116) and patients without DM (n=429). First, the on-device survival and incidence of adverse events were evaluated. Second, after adjusting for patients' backgrounds, the change of laboratory data in the 2 groups were compared. Overall, on-device survival at 1, 2, and 3 years was almost equivalent between the 2 groups; it was 95%, 94%, and 91% in patients without DM, and 93%, 91%m and 91% in patients with DM (P=0.468) The incidence of adverse events was similar between 2 groups of patients, except for driveline exit site infection in the adjusted cohort. Cox proportional hazards regression analysis revealed younger age (HR: 0.98 (95% confidence interval (CI): 0.97-0.99, P=0.001) and presence of DM (HR: 1.83 (95% CI: 1.14-2.88), P=0.016) as significant predictors of driveline infection. Laboratory findings revealed no differences between groups throughout the periods.

CONCLUSIONS

The clinical results after LVAD implantation in DM patients were comparable with those in non-DM patients, except for the driveline exit site infection.

Short-Term Outcomes of Magnetically Levitated Left Ventricular Assist Device in Advanced Heart Failure - The Japanese Cohort

BACKGROUND

The superiority of a fully magnetically levitated centrifugal-flow left ventricular assist device (LVAD) in terms of overall survival, stroke events and pump thrombosis has been demonstrated in previous international analyses, so we evaluated a Japanese cohort for the same.

METHODS AND RESULTS

This retrospective observational study was conducted at Osaka University Medical Hospital and the National Cerebral and Cardiovascular Center in Japan. A total of 75 consecutive patients who underwent HeartMate3 (HM3) implantation were included. The primary endpoint was on-device survival, and the secondary endpoint was the incidence of LVAD-related complications at 2 years. All parameters were compared with those of the previously performed HeartMate II (HMII) implantation in 197 cases. The on-device survival rates were 94.7% and 92.3% in the HM3 and HMII groups, respectively, at the 2-year follow-up (P=0.62). The rehospitalization-free rate after implantation was 61.8% in the HM3 group, which was significantly higher than that in the HMII group (relative risk, 0.35; 95% confidence interval [CI], 0.23-0.55; P<0.0001). Event-free survival rates from cerebral cerebrovascular events and pump thrombosis in the HM3 group were significantly higher than those in the HMII group, at 97.2% and 100%, respectively (relative risk, 0.14; 95% CI 0.03-0.58); P=0.0015 and relative risk, not calculated; P=0.049, respectively).

CONCLUSIONS

Satisfactory short-term outcomes were observed after HM3 implantation in a Japanese cohort.

Cerebral Microbleeds During Transcatheter Aortic Valve Replacement: A Prospective Magnetic Resonance Imaging Cohort

BACKGROUND

Cerebral microbleeds (CMBs) have been observed in healthy elderly people undergoing systematic brain magnetic resonance imaging. The potential role of acute triggers on the appearance of CMBs remains unknown. We aimed to describe the incidence of new CMBs after transcatheter aortic valve replacement (TAVR) and to identify clinical and procedural factors associated with new CMBs including hemostatic measures and anticoagulation management.

METHODS

We evaluated a prospective cohort of patients with symptomatic aortic stenosis referred for TAVR for CMBs (METHYSTROKE [Identification of Epigenetic Risk Factors for Ischemic Complication During the TAVR Procedure in the Elderly]). Standardized neurologic assessment, brain magnetic resonance imaging, and analysis of hemostatic measures including von Willebrand factor were performed before and after TAVR. Numbers and location of microbleeds on preprocedural magnetic resonance imaging and of new microbleeds on postprocedural magnetic resonance imaging were reported by 2 independent neuroradiologists blinded to clinical data. Measures associated with new microbleeds and postprocedural outcome including neurologic functional outcome at 6 months were also examined.

RESULTS

A total of 84 patients (47% men, 80.9±5.7 years of age) were included. On preprocedural magnetic resonance imaging, 22 patients (26% [95% CI, 17%-37%]) had at least 1 microbleed. After TAVR, new microbleeds were observed in 19 (23% [95% CI, 14%-33%]) patients. The occurrence of new microbleeds was independent of the presence of microbleeds at baseline and of diffusion-weighted imaging hypersignals. In univariable analysis, a previous history of bleeding (P=0.01), a higher total dose of heparin (P=0.02), a prolonged procedure (P=0.03), absence of protamine reversion (P=0.04), higher final activated partial thromboplastin time (P=0.05), lower final von Willebrand factor high-molecular-weight:multimer ratio (P=0.007), and lower final closure time with adenosine-diphosphate (P=0.02) were associated with the occurrence of new postprocedural microbleeds. In multivariable analysis, a prolonged procedure (odds ratio, 1.22 [95% CI, 1.03-1.73] for every 5 minutes of fluoroscopy time; P=0.02) and postprocedural acquired von Willebrand factor defect (odds ratio, 1.42 [95% CI, 1.08-1.89] for every lower 0.1 unit of high-molecular-weight:multimer ratio; P=0.004) were independently associated with the occurrence of new postprocedural microbleeds. New CMBs were not associated with changes in neurologic functional outcome or quality of life at 6 months.

CONCLUSIONS

One out of 4 patients undergoing TAVR has CMBs before the procedure and 1 out of 4 patients develops new CMBs. Procedural or antithrombotic management and persistence of acquired von Willebrand factor defect were associated with the occurrence of new CMBs.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02972008.

Staphylococcus-induced proliferative glomerulonephritis and cerebral hemorrhage - fatal complications in a young female with postpartum cardiomyopathy and an implanted left ventricular assist device: a case report and review of the literature

Background: The continuous-flow left ventricular assist device (CF-LVAD) is used to save the lives of patients in the final stage of congestive heart failure, replacing the pump function of the left ventricle. Although quality of life increases significantly, CF-LVAD-related complications might prove fatal, as in the case presented in this paper.Methods: A 20-year-old female, during her second pregnancy, presented with signs of heart failure. Emergency caesarean section was necessary to save the baby, but peripartum cardiomyopathy developed in the mother. The use of an implantable cardioverter-defibrillator (ICD) was necessary 5 years later. As the clinical progression was unfavorable under medical treatment, with the patient reaching INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) Profile 1 (refractory cardiogenic shock), the treatment of choice was the implantation of a CF-LVAD.Results: After 3 years of follow-up (at the age of 28), the patient presented with a positive hemoculture for Staphylococcus aureus. Prolonged antibiotic therapy and attentive follow-up was prescribed. Although an effective antiplatelet and anticoagulant treatment was applied, and despite therapeutic values of prothrombin time and international normalized ratio (INR), the patient died as result of a fatal cerebral hemorrhage. The autopsy also revealed septic emboli, disseminated intravascular coagulation, and focal proliferative glomerulonephritis.Conclusions: Although the benefits of CF-LVAD are significant, bleeding episodes can be severe and LVAD-associated infection can trigger glomerular injury and increase mortality.

Highly feasible procedure for laparoscopic transplantation of cell sheets under pneumoperitoneum in porcine model

INTRODUCTION

Cell sheet technology is one of the most successful methodologies in regenerative medicine. Various applications of cell sheets have been introduced in first-in-human studies in several clinical fields. When transplanting a cell sheet into internal organs, a relatively large incision is required for delivery due to difficulty handling the sheet. We developed a laparoscopic delivery procedure for safe and easy transplantation of cell sheets in a porcine model.

METHODS

Pneumoperitoneum was established by inflation with CO₂. First, to increase the strength during handling, fibrin was sprayed onto the surface of the cell sheet, and then a myoblast sheet was placed onto the newly developed carrier. The sheets were pinched with laparoscopic forceps to insert into the abdominal cavity through the laparoscopic port. Myoblast sheets were then applied to the surface of the liver, colon, small intestine, and stomach, and procedure times were measured. At three days post transplantation, a histopathological examination was performed to confirm engraftment of the sheet. The function and engraftment were also analyzed in a duodenal endoscopic submucosal dissection (ESD) model.

RESULTS

The fibrin-processed myoblast sheet was able to be managed with conventional laparoscopic forceps without breaking. Despite the drastic change in air pressure by passing through the laparoscopic port, the sheets suffered no apparent damage. The transplantation procedure times did not markedly differ among transplant sites. A histopathological examination revealed thin-layered, desmin-positive cells at each transplant site. With transplantation following ESD, the engrafted myoblast sheets effectively prevented delayed perforation.

CONCLUSIONS

Our procedure is simple, and the system involves a carrier made of medically fit silicon, commercially available fibrin glue and conventional laparoscopic forceps. Our procedure is a powerful tool for laparoscopical cell sheet transplantation.

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.

A Multi-Domain Simulation Study of a Pulsatile-Flow Pump Device for Heart Failure With Preserved Ejection Fraction

Mechanical circulatory support (MCS) devices are currently under development to improve the physiology and hemodynamics of patients with heart failure with preserved ejection fraction (HFpEF). Most of these devices, however, are designed to provide continuous-flow support. While it has been shown that pulsatile support may overcome some of the complications hindering the clinical translation of these devices for other heart failure phenotypes, the effects that it may have on the HFpEF physiology are still unknown. Here, we present a multi-domain simulation study of a pulsatile pump device with left atrial cannulation for HFpEF that aims to alleviate left atrial pressure, commonly elevated in HFpEF. We leverage lumped-parameter modeling to optimize the design of the pulsatile pump, computational fluid dynamic simulations to characterize hydraulic and hemolytic performance, and finite element modeling on the Living Heart Model to evaluate effects on arterial, left atrial, and left ventricular hemodynamics and biomechanics. The findings reported in this study suggest that pulsatile-flow support can successfully reduce pressures and associated wall stresses in the left heart, while yielding more physiologic arterial hemodynamics compared to continuous-flow support. This work therefore supports further development and evaluation of pulsatile support MCS devices for HFpEF.

Risk factors of gynecological bleeding in female patients with left-ventricular assist device

Women with implantable left-ventricular assist devices (LVADs) experience gynecological bleeding (GYN-bleeding). However, a few studies have investigated female-specific problems. Therefore, this study aimed to identify the risk factors for adverse GYN-bleeding after LVAD implantation. We retrospectively analyzed 59 women (mean age: 41 ± 15 years) with long-term implantable LVAD support (≥ 6 months) at our institution between 2005 and 2018. The history of GYN-bleeding before implantation was defined as abnormal utero-ovarian bleeding, excessive menstruation, uterine fibroids, and endometrial lesions. GYN-bleeding after implantation was defined as a requirement of emergency outpatient visits and/or hospitalization, blood transfusions, hormonal therapy, and/or surgery. Additionally, risk factors for GYN-bleeding were identified using the Cox regression model. Twenty-four GYN-bleeding cases were seen in 15 patients (two times: five patients, three times: two patients, 0.18 events per patient-year). The 1- and 2-year GYN-bleeding-free rates were 84% and 73%, respectively. Twelve patients (17 events) required RBC ≥ 4 units, and five patients (7 events) required FFP ≥ 4 units. Seven patients required pseudomenopausal treatment after blood transfusion, and four patients required surgical treatment. Fifteen patients with GYN-bleeding after implantation were significantly younger than the remaining 44 patients without GYN-bleeding (34 ± 12 years vs. 43 ± 16 years, P = 0.02). Multivariable risk analysis showed a history of GYN-bleeding before implantation was a significant risk factor (hazard ratio 3.7 [1.2-10.6], P = 0.004). Patients with a history of GYN-bleeding before LVAD implantation have a high risk of developing GYN-bleeding after implantation. We should identify the high-risk population and prepare for the management of GYN-bleeding.

Ventricular Assist Device Driveline Infections: A Systematic Review

Infection is the most common complication in patients undergoing ventricular assist device (VAD) implantation. Driveline exit site (DLES) infection is the most frequent VAD infection and is a significant cause of adverse events in VAD patients, contributing to morbidity, even mortality, and repetitive hospital readmissions. There are many risk factors for driveline infection (DLI) including younger age, smaller constitution of patients, obesity, exposed velour at the DLES, longer duration of device support, lower cardiac index, higher heart failure score, DLES trauma, and comorbidities such as diabetes mellitus, chronic kidney disease, and depression. The incidence of DLI depends also on the device type. Numerous measures to prevent DLI currently exist. Some of them are proven, whereas the others remain controversial. Current recommendations on DLES care and DLI management are predominantly based on expert consensus and clinical experience of the certain centers. However, careful and uniform DLES care including obligatory driveline immobilization, previously prepared sterile dressing change kits, and continuous patient education are probably crucial for prevention of DLI. Diagnosis and treatment of DLI are often challenging because of certain immunological alterations in VAD patients and microbial biofilm formation on the driveline surface areas. Although there are many conservative and surgical methods described in the DLI treatment, the only possible permanent solution for DLI resolution in VAD patients is heart transplantation. This systematic review brings a comprehensive synthesis of recent data on the prevention, diagnostic workup, and conservative and surgical management of DLI in VAD patients.

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.

Characteristics and Outcomes of Left Ventricular-Assist Device-Associated Cerebrovascular Events in Setting of Infectious Intracranial Aneurysms

Background and purpose: The study aims to identify the characteristics and neurological outcomes of the left ventricular-assist device (LVAD)-associated cerebrovascular events (CVE) and infections, particularly in the setting of infectious intracranial aneurysms (IIA).

Methods: A single-center retrospective review of patients having undergone LVAD implantation between 2011 and 2017 was conducted using institutional registries and screened for CVE. Patients with CVE were assessed for concurrent bacteremia; neurovascular imaging was then used to isolate patients with IIA. A review of comorbidities, imaging characteristics, and management were performed to determine predictors of neurological outcomes, as defined by the 90-day modified Rankin scale (mRS) scores.

Results: Of the 383 HeartMate II LVAD implantations performed, 43 all-cause stroke events were identified across 35 (9%) patients. The majority of the events were hemorrhagic CVE (n=28) with 21 events complicated by bacteremia. Of patients with hemorrhagic CVE and bacteremia, Staphylococcus aureus (n=10) and Pseudomonas aeruginosa (n= 8) infection were the most frequently associated organisms. Severe disability or death (90-day mRS > 4) was observed in 15 patients (63%). Seven patients had confirmed findings of IIA on diagnostic cerebral angiogram and were associated with distal middle cerebral artery (MCA) territory involvement (n=6; 86%) with concurrent Staphylococcus (n=5, 71%) and/or Pseudomonas (n=4, 57%) infections. Overall, a higher incidence of acute and chronic bacteremia was observed in the hemorrhagic CVE subgroup compared to the ischemic CVE subgroup (74% vs 36% & 71% vs 29%, respectively; p <0.05). Despite endovascular and/or surgical intervention in patients with IIA, four patients failed management and elected for comfort measures.

Conclusion: Our results indicate that P. aeruginosa and S. aureus bacteremia are associated with a greater incidence of intracranial hemorrhage and worse neurological outcomes. Future management considerations may include pre-implantation cerebrovascular imaging to assess vascular pathology including prior aneurysms and intracranial atherosclerotic disease burden as a screen for higher-risk patients, as well as more aggressive antibiotic therapy at bacteremia onset.

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.

Cerebral Microbleeds and Intracranial Hemorrhages in Adult Patients on Extracorporeal Membrane Oxygenation-Autopsy Study

Supplemental Digital Content is available in the text.

Objectives:

Current studies lack robust information on the prevalence and associated factors of cerebral microbleeds in patients who underwent extracorporeal membrane oxygenation.

Design:

Retrospective analysis.

Setting:

We reviewed patients who underwent (extracorporeal membrane oxygenation) and subsequent brain autopsy with gross and microscopic examinations from January 2009 to December 2018 from a single tertiary center.

Patients:

Twenty-five extracorporeal membrane oxygenation patients (median age, 53 yr; interquartile range, 36–61 yr; 17 women and 8 men) underwent brain autopsy.

Interventions:

Descriptive analysis of neuropathologic findings. Cerebral microbleed was defined as a small focus (< 10 mm diameter) of accumulation of blood product in the brain tissue. Macrohemorrhage was defined as any of the grossly identifiable epidural, subdural, subarachnoid, or intraparenchymal hemorrhages larger than 10 mm.

Measurement and Main Results:

Of 25 (22 venoarterial extracorporeal membrane oxygenation; three venovenous extracorporeal membrane oxygenation), 15 patients (60%) were found to have cerebral microbleeds, whereas 13 (52%) had macrohemorrhages, of whom five (20%) had both. Overall, 92% of brains demonstrated the presence of either cerebral microbleeds or macrohemorrhages after extracorporeal membrane oxygenation support. Of the patients with cerebral microbleeds, lobar cerebral microbleeds (80%) occurred more frequently than deep cerebral microbleeds (60%), with 40% of patients having both types. The cases of macrohemorrhages consisted of one epidural (8%), two subdural (15%), and 10 subarachnoid hemorrhages (77%). In univariate analyses, the presence of macrohemorrhages was significantly associated with the presence of cerebral microbleeds (p = 0.03) with odds ratio of 0.13 (CI, 0.02–0.82). Age, sex, extracorporeal membrane oxygenation duration, extracorporeal membrane oxygenation type, use of aspirin or dialysis during extracorporeal membrane oxygenation support, bloodstream infections, hemoglobin, platelets, and coagulopathy profiles were not associated with cerebral microbleeds.

Conclusions:

In patients with postmortem neuropathologic evaluation, 92% sustained acute cerebral microbleeds or macrohemorrhages after extracorporeal membrane oxygenation support. Cerebral microbleeds were commonly present in the majority of extracorporeal membrane oxygenation nonsurvivors. Further research is necessary to study the long-term sequelae, such as cognitive outcome of extracorporeal membrane oxygenation-associated cerebral microbleeds in extracorporeal membrane oxygenation survivors.

Human pituitary development and application of iPSCs for pituitary disease

The pituitary plays a pivotal role in maintaining systemic homeostasis by secreting several hormones. During fetal development, the pituitary develops from the oral ectoderm in contact with the adjacent hypothalamus. This process is regulated by the fine-tuned expression of transcription and growth factors. Impairments of this process result in congenital pituitary hypoplasia leading to dysfunction of the pituitary. Although animal models such as knockout mice have helped to clarify these underlying mechanisms, the developmental processes of the human pituitary gland and the mechanisms of human pituitary disorders have not been fully understood. This is because, at least in part, of the lack of a human pituitary developmental model. Recently, methods for in vitro induction of the pituitary gland from human pluripotent stem cells were developed. These models can be utilized not only for regenerative medicine but also for human pituitary studies on developmental biology and for modeling of pituitary disorders, such as hypopituitarism and pituitary tumors. In this review, we provide an overview of recent progress in the applications of pluripotent stem cells for pituitary research and discuss further perspectives for pituitary studies.

Ventricular Assist Device-Specific Infections

Ventricular assist device (VAD)-specific infections, in particular, driveline infections, are a concerning complication of VAD implantation that often results in significant morbidity and even mortality. The presence of a percutaneous driveline at the skin exit-site and in the subcutaneous tunnel allows biofilm formation and migration by many bacterial and fungal pathogens. Biofilm formation is an important microbial strategy, providing a shield against antimicrobial treatment and human immune responses; biofilm migration facilitates the extension of infection to deeper tissues such as the pump pocket and the bloodstream. Despite the introduction of multiple preventative strategies, driveline infections still occur with a high prevalence of ~10-20% per year and their treatment outcomes are frequently unsatisfactory. Clinical diagnosis, prevention and management of driveline infections are being targeted to specific microbial pathogens grown as biofilms at the driveline exit-site or in the driveline tunnel. The purpose of this review is to improve the understanding of VAD-specific infections, from basic "bench" knowledge to clinical "bedside" experience, with a specific focus on the role of biofilms in driveline infections.

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.

Brain magnetic resonance imaging in adult survivors of extracorporeal membrane oxygenation

Despite the common occurrence of neurologic complications in patients with extracorporeal membrane oxygenation (ECMO), data on magnetic resonance imaging (MRI) findings in adult ECMO are limited. We aimed to describe the MRI findings of patients after ECMO cannulation. Records of patients who underwent ECMO from September 2017 to June 2019 were reviewed. MRI studies were performed using multiplanar sequences consisting of T1-, T2-weighted, fluid attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI), and susceptibility weighted images (SWI). Of the 78 adult patients who underwent ECMO, 26 (33%) survived. Of 26, eight patients (31%) had MRI studies, with a median age of 47 years (interquartile range [IQR]: 25-57). The median ECMO support time was 8 days (IQR: 4-25) and the median time from decannulation to MRI was 12 days (IQR: 1-34). Five (63%) of eight patients had ischemic infarcts; 4 (50%) had cerebral microhemorrhage; 2 (25%) had intracranial hemorrhage; and 1 (13%) had thoracic cord ischemic infarct. There were no patients with normal MRI. All patients underwent transcranial Doppler (TCD). Four of 8 (50%) showed presence of microemboli with TCD; 3 of 4 (75%) had ischemic infarcts; and 1 of 4 (25%) had presence of multiple cerebral microhemorrhages on MRI. All ischemic infarcts had diffuse pattern of punctate to small lesions for ECMO survivors. The location of cerebral microhemorrhages included lobar (n = 4, 100%), deep (n = 2, 50%), and both (n = 2, 50%). Of the MRI studies, cerebrovascular related lesions were the most frequent, with punctate ischemic infarct being the most common type that may be associated with TCD microemboli. The results of the study suggest that subclinical cerebral lesions are commonly found in patients with ECMO support. Further research is needed to understand long-term effect of these cerebral lesions.

Effect of the Creatinine Excretion Rate Index, a Marker of Sarcopenia, on Prediction of Intracranial Hemorrhage in Patients With Advanced Heart Failure and a Continuous-Flow Left Ventricular Assist Device

BACKGROUND

Sarcopenia is characterized by progressive loss of skeletal muscle and has frequently been associated with poor clinical outcomes in patients with advanced heart failure (HF). The urinary creatinine excretion rate (CER) index is an easily measured marker of muscle mass, but its predictive capacity for mortality and cerebrovascular events has not been investigated in patients with a continuous-flow implantable left ventricular assist device (CF-iLVAD).

METHODS AND RESULTS

We retrospectively reviewed 147 patients (mean [±SD] age 43.7±12.5 years, 106 male) who underwent CF-iLVAD implantation between April 2011 and June 2019. CER indices in 24-h urine samples before CF-iLVAD implantation were determined. Over a median follow-up of 2.3 years, there were 10 (6.8%) deaths and 43 (29.3%) cerebrovascular events. Patients were divided into 2 groups (low and high CER index) according to the median CER index in men and women (i.e., 13.71 and 12.06 mg·kg-1·day-1, respectively). Mortality and intracranial hemorrhage rates after CF-iLVAD implantation were significantly higher in the low than high CER index group (mortality 12.3% vs. 1.4% [P<0.01]; intracranial hemorrhage 23.3% vs. 8.1% [P=0.01]). Multivariate Cox proportional hazard models revealed that a low CER index was an independent predictor of intracranial hemorrhage in patients receiving a CF-iLVAD (hazard ratio 3.63; 95% confidence interval 1.43-9.24; P<0.01).

CONCLUSIONS

A low preoperative CER index is an independent, non-invasive predictor of intracranial hemorrhage after CF-iLVAD implantation.

Bionic women and men - Part 1: Cardiovascular lessons from heart failure patients implanted with left ventricular assist devices

NEW FINDINGS

What is the topic of this review? Patients with advanced heart failure who are implanted with left ventricular assist devices (LVADs) present an opportunity to understand the human circulation under extreme conditions. What advances does it highlight? LVAD patients have a unique circulation that is characterized by a reduced or even absent arterial pulse. The remarkable survival of these patients is accompanied by circulatory complications, including stroke, gastrointestinal bleeding and right-heart failure. Understanding the mechanisms related to the complications in LVAD patients will help the patients and also advance our fundamental understanding of the human circulation in general.

ABSTRACT

Some humans with chronic, advanced heart failure are surgically implanted with a left ventricular assist device (LVAD). Because the LVAD produces a continuous flow, a palpable pulse is often absent in these patients. This allows for a unique investigation of the human circulation and has created a controversy around the 'need' for a pulse. The medical debate has also generated a more generic, fundamental discussion into what is 'normal' arterial physiology and health. The comprehensive study and understanding of the arterial responses to drastically altered haemodynamics due to continuous-flow LVADs, at rest and during activity, presents an opportunity to significantly increase our current understanding of the fundamental components of arterial regulation (flow, blood pressure, sympathetic activity, endothelial function, pulsatility) in a way that could never have been studied previously. In a series of four articles, we summarize the talks presented at the symposium entitled 'Bionic women and men - Physiology lessons from implantable cardiac devices' presented at the 2019 Annual Meeting of The Physiological Society in Aberdeen, UK. The articles highlight the novel questions generated by physiological phenomena observed in LVAD patients and propose future areas of interest within the field of cardiovascular physiology.

Reduced Activity of von Willebrand Factor after Flow-Diverting Stent Implantation for Intracranial Aneurysms: A Link to Acquired von Willebrand Disease?

BACKGROUND AND PURPOSE

Vascular devices generating high shear stress can cause type 2A acquired von Willebrand disease, which is characterized by low von Willebrand factor activity accompanied by hemorrhagic complications. The braided mesh structure of flow-diverting stents with a relatively small strut size can create abnormally high shear stress while arterial blood flows through the stent struts into the aneurysm, and flow-diverting stent may be associated with reduced von Willebrand factor activity.

MATERIALS AND METHODS

Aneurysmal morphologic parameters and patient data were examined retrospectively among patients who had an unruptured intracranial aneurysm treated with a flow-diverting stent. The RISTOtest (test for whole blood ristocetin-induced platelet aggregation) for von Willebrand factor activity, as well as tests for aspirin and clopidogrel/prasugrel effectiveness, were performed immediately before the endovascular procedure and 24 hours later by multiple electrode aggregometry.

RESULTS

A total of 39 patients with 56 aneurysms were recruited, and statistical analyses were performed in 32 patents with 49 aneurysms. Compared with the baseline values, von Willebrand factor activity was reduced in 16 patients but increased in 23 patients. Aneurysmal variables (eg, neck area, volume, volume-to-neck area ratio, size ratio, and morphologic index) clearly distinguished patients with reduced von Willebrand factor activity from those with nonreduced von Willebrand factor activity. The receiver operating characteristic curve showed that the morphologic index and volume had the highest discriminative power, with an area under the curve of 0.99.

CONCLUSIONS

In high-volume/large-neck aneurysms, flow-diverting stent implantation can cause reduced von Willebrand factor activity, which may be linked causally to acquired von Willebrand disease.

Mesangioproliferative glomerulonephritis with extracapillary crescents - unexpected fatal complication in a 17-year-old patient with implanted left ventricular assist device

The continuous flow left ventricular assist device (cf-LVAD) is the life-saving solution for patients with end-stage global heart failure. We present the case of a young patient with biventricular dilated cardiomyopathy, who had a cf-LVAD implantation and died as result of progressive renal failure. In the first year after implantation, he suffered repeated strokes and episodes of pneumonia with Klebsiella pneumoniae and Escherichia coli. The patient had hypertension, which was kept under control with angiotensin-converting enzyme (ACE) inhibitors and beta-blockers. After multiple bleeding episodes, the patient died at 21 months after the LVAD implant. At autopsy, parenchymatous brain hemorrhage was found to be associated with pulmonary hemorrhages. The unexpected features related to mesangioproliferative and extracapillary glomerulonephritis, with focal glomerulosclerosis. The proliferated parietal cells of Bowman’s capsule proved to express cluster of differentiation 44 (CD44), whereas remnant podocytes and mesangial cells showed Wilms tumor 1 (WT1) positivity. Since CD44 might be involved in fibrogenesis, but ACE inhibitors can exert a protective role against glomerular deterioration, we performed a synthesis of literature data which enabled us to propose a hypothesis with a potential clinical impact. We conclude that, in patients with LVAD implants, high blood pressure and high serum level of angiotensin II, the association between ACE inhibitors and anti-CD44 agents might exert glomerular protection and increase the survival time. Experimental studies are necessary to support our hypothesis and to explain the mechanism of possible glomerulopathy installed after LVAD implant.

Infective endocarditis of bovine pericardial patch in the aortic position in a patient with left ventricular assist device

A 53-year old woman, who had a history of left ventricular assist device implantation for acromegalic cardiomyopathy and aortic valve closure with bovine pericardial patch, was diagnosed with active endocarditis of aortic valve closure patch. The investigation revealed that infection was limited to the aortic valve closure patch; thus, redo aortic valve closure with a new bovine pericardial patch was performed. The postoperative course was uneventful and the infection was sufficiently controlled. Early surgical intervention is mandatory for a good result without spread of infection to the left ventricular assist device pump and formation of embolism.

Risk of stroke early after implantation of a left ventricular assist device

OBJECTIVE

Stroke is one of the major adverse events after left ventricular assist device implantation. Risk of stroke is the highest immediately after left ventricular assist device implantation and then increases again in chronic periods. There is no study that has analyzed risk factors for stroke in acute phase. We investigated the risk factors for stroke in the acute phase after left ventricular assist device implantation in the present study.

METHODS

Between October 2005 and December 2016, 158 consecutive patients (mean age, 43 ± 14 years; 34% were women) underwent continuous-flow left ventricular assist device (50 HeartMate II [Abbott Medical, Abbott Park, Ill], 38 DuraHeart [Terumo Heart, Ann Arbor, Mich], 33 Jarvik2000 [Jarvik Heart, New York, NY], 23 EVAHEART [Sun Medical, Moriyama City, Japan], 14 HeartWare [Framingham, Mass]) implantation in our institution. We analyzed the risk factors for a symptomatic stroke within 90 days after left ventricular assist device implantation.

RESULTS

Stroke occurred in 28 patients in the acute phase after left ventricular assist device implantation. Multivariate analysis revealed that low cardiac output (odds ratio, 0.25; 0.07-0.92; P = .024) during postoperative 12 to 24 hours was the only independent risk factor for stroke in the acute phase. Patients with stroke in the acute phase had higher serum lactate dehydrogenase levels at any point until postoperative 14 days. Patients with the HeartMate II device particularly showed a statistically significant negative relationship between cardiac output during postoperative 12 to 24 hours and serum lactate dehydrogenase levels at postoperative 14 days (r = -0.313, P = .03).

CONCLUSIONS

Our study demonstrated that patients with perioperative lower cardiac output and higher lactate dehydrogenase level developed stroke in the acute phase after left ventricular assist device implantation. These results suggested that maintenance of sufficient left ventricular assist device flow is important in prevention of stroke, which may be related to subclinical pump thrombosis.

Clinical Results, Adverse Events, and Change in End-Organ Function in Elderly Patients With HeartMateII Left Ventricular Assist Device - Japanese Multicenter Study

BACKGROUND

Advanced age has an adverse impact on clinical results in left ventricular assist device (LVAD) patients. We compared the clinical results of patients aged >60 years with younger patients using a national Japanese database.

METHODS AND RESULTS

Between April 2013 and December 2016, 300 patients underwent HeartMateII implantation. Of these, 37 patients were ≥60 years at LVAD implantation, and the clinical results of these patients were compared with the other younger 263 patients. At 1 and 3 years the on-device survival was 95%, 91% in younger patients, and 85%, 75% in older patients, respectively (P=0.016), although age was not a risk factor on the multivariate analysis. There was no significant difference between the groups in incidence of various adverse events except stroke. In the propensity-matching cohort, the incidence of stroke was significantly higher in patients aged >60 years (P=0.047). In patients aged >60 years, improvement of renal function was transient and there was no improvement later than 3 months, and recovery of serum albumin level to preoperative value was delayed.

CONCLUSIONS

There were significant differences in the stroke incidence and recovery of end-organ functions after LVAD implantation. This may have important implications for patient selection in future destination therapy in Japan, where quality of life is an important issue in LVAD support.