Platelet count in heart failure patients undergoing left ventricular assist device

AIMS

Left ventricular assist device (LVAD) implantation, a therapy for end-stage heart failure, is associated with platelet (PLT) activation. This study aims to evaluate the prognostic impact of PLT count in patients with LVAD implantation.

METHODS AND RESULTS

Data from the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) registry were investigated, and patients were divided into three groups according to tertiles. The dynamic change of PLT counts and its associations with long-term outcomes were analysed. The primary outcome was long-term mortality. A total of 19 517 patients who received the first continuous-flow LVAD were identified from the INTERMACS registry. The PLT count underwent a dynamic change towards normalization after LVAD implantation. Compared with intermediate, both high (hazard ratio [HR], 1.09, 95% confidence interval [CI]: 1.01 to 1.17, P = 0.033) and low (HR, 1.18, 95% CI: 1.10 to 1.27, P < 0.001) pre-implant PLT counts were associated with an increased risk of 2 year mortality. Compared with intermediate, a high post-implant PLT count was associated with an increased risk of 4 year mortality (HR, 1.38, 95% CI: 1.26 to 1.52, P < 0.001). Besides, both pre- and post-implant PLT counts exhibit a U-shaped association with the risk of mortality.

CONCLUSIONS

LVAD implantation could improve the PLT count towards normalization. Abnormal pre-/post-implant PLT counts were independently associated with increased risks of long-term mortality.

HeartMate 3 implantation with an emphasis on the biventricular configuration

OBJECTIVES

Right ventricular failure following implantation of a durable left ventricular assist device (LVAD) is a major driver of mortality. Reported survival following biventricular (BiVAD) or total artificial heart (TAH) implantation remains substantially inferior to LVAD alone. We report our outcomes with LVAD and BiVAD HeartMate 3 (HM3).

METHODS

Consecutive patients undergoing implantation of an HM3 LVAD between November 2014 and December 2021, at The Alfred, Australia were included in the study. Comparison was made between the BiVAD and LVAD alone groups.

RESULTS

A total of 86 patients, 65 patients with LVAD alone and 21 in a BiVAD configuration underwent implantation. The median age of the LVAD and BiVAD groups was 56 years (Interquartile range 46-62) and 49 years (Interquartile range 37-55), respectively. By 4 years after implantation, 54% of LVAD patients and 43% of BiVAD patients had undergone cardiac transplantation. The incidence of stroke in the entire experience was 3.5% and pump thrombosis 5% (all in the RVAD). There were 14 deaths in the LVAD group and 1 in the BiVAD group. The actuarial survival for LVAD patients at 1 year was 85% and BiVAD patients at 1 year was 95%.

CONCLUSIONS

The application of HM 3 BiVAD support in selected patients appears to offer a satisfactory solution to patients requiring biventricular support.

Outcomes of treatment for deep left ventricular assist device infection

OBJECTIVE

Among left ventricular assist device patients, the most commonly infected component is the drive line, which can be managed with antibiotics and local debridement. Infection of intrathoracic device components is less common but more difficult to manage. Herein we describe the incidence of deep device infection (DDI) at our center as well as management and outcomes.

METHODS

We retrospectively reviewed 658 patients who underwent implantable left ventricular assist device insertion with HeartMate 2 (Abbott) or HeartMate 3 (Abbott) devices between January 2004 and June 2021. DDI was defined according to radiographic and clinical criteria. Cumulative incidence was calculated using a Fine-Gray subdistribution model; survival analysis was performed using the method of Kaplan and Meier.

RESULTS

There were 32 (4.8%) DDIs during this study period. Drive line infection and re-exploration for bleeding were associated with development of DDI. Cumulative incidence of DDI increased over time, affecting 11% (7%-18%) at 5 years. The dominant microbes involved in DDI were Pseudomonas aeruginosa (19%) and methicillin-resistant Staphylococcus aureus (13%). Nineteen patients (59%) with device infection underwent device exchange, 6 (19%) underwent initial transplant, and 7 (22%) were treated solely with debridement and antibiotics. Of those who underwent device exchange, 12 (63%) developed reinfection of their new device and 6 underwent subsequent heart transplant. Patients who underwent transplantation for management of device infection had improved 5-year survival (80% vs 11%; P = .01) but 3 patients (25%) developed deep sternal wound infection after transplant.

CONCLUSIONS

DDI is a rare but challenging complication in this destination era. Heart transplantation is the preferred management strategy for eligible patients but infectious complication is common.

Bleeding and thrombotic complications and their impact on mortality in patients supported with left ventricular assist device for cardiogenic shock

INTRODUCTION

Thrombosis and bleeding are major complications in patients supported with left ventricular assist devices (LVADs). We aimed to assess the incidence of bleeding and thrombosis in patients supported with a HeartWare left ventricular assist device (HVAD), their predictive factors and their impact on mortality.

METHODS

A single centre retrospective observational study of patients supported with HVAD over 5 years from January 2015 to October 2020.

RESULTS

A total 139 patients (median age 52.5, 72.1% male) were included for analysis. The probability of 1-year survival was 73.1%. Advanced age (>60 years) and EuroSCORE II score (>20%) were independently associated with reduced survival. Major bleeding and thrombosis occurred in 46.8% and 35.3% respectively. Secondary mechanical circulatory support (MCS) increased likelihood of experiencing major bleeding (HR: 2.76, 95%1.65-4.62, p < 0.0001) whilst patients receiving aspirin were protected from bleeding and thrombosis (HR: 0.34 95% CI 0.19-0.58, p < 0.001). Pre-operative anaemia (HR: 3.02, 95% CI: 1.6-5.7, p = 0.014) and use of a secondary MCS device (HR: 2.78, 95% CI: 1.2-6.3, p = 0.001) were associated with an increased risk of thrombosis. Patients with any major bleeding (with or without thrombosis) had a 7.68-fold (95% CI 3.5-16.8) increased risk of death compared to those without. In contrast, 'thrombosis only' patients had 4.23-fold (95% CI 1.8-10.2) increased risk of death compared to those without thrombosis. The risk of mortality was increased in patients with any thrombosis and the risk of death was highest in patients with major bleeding and thrombosis (HR: 16.49 [95% CI 7.7-35.3]).

CONCLUSIONS

Major bleeding and thrombosis significantly increase the 1-year mortality. Optimal perioperative haemostasis and anticoagulation remains crucial in patients supported with HVAD.

Effect of Early Amiodarone Use on Warfarin Sensitivity, Blood Product Use, and Bleeding in Patients With a Left Ventricular Assist Device

Data are scarce on the effect of amiodarone on warfarin sensitivity and related outcomes after placement of a left ventricular assist device (VAD). This retrospective study compared 30-day outcomes between patients on amiodarone vs no amiodarone after VAD implant. After exclusions, 220 patients received amiodarone and 136 patients did not. Compared to the no amiodarone group, the amiodarone group had a higher warfarin dosing index (0.53 [0.39, 0.79] vs 0.46 [0.34, 0.63]; P = 0.003), incidence of INR ≥ 4 (40.5 vs 23.5%; P = 0.001), incidence of bleeding (24.1 vs 14%; P = 0.021), and use of INR reversal agents (14.5 vs 2.9%, P ≤ 0.001). Amiodarone was associated with bleeding (OR, 1.95; 95% CI, 1.10-3.47; P = 0.022), but not after adjusting for age, estimated glomerular filtration rate, and platelet count (OR, 1.67; 95% CI, 0.92-3.03; P = 0.089). After VAD implant, amiodarone was associated with increased warfarin sensitivity and administration of INR reversal agents.

Bleeding After LVAD Implant: If Things Do Not Add Up, Take a Look!

A 63-year-old male underwent re-exploration after HVAD implantation due to persistent postoperative bleeding. We present an unusual cause of postoperative bleeding after LVAD implantation for which early re-exploration and consideration of unusual etiologies is appropriate.

The Use of Factor Eight Inhibitor Bypass Activity (FEIBA) for the Treatment of Perioperative Hemorrhage in Left Ventricular Assist Device Implantation

OBJECTIVE

To test the hypothesis that factor eight inhibitor bypassing activity (FEIBA) can be used to control bleeding following left ventricular assist device (LVAD) implantation without increasing the 14-day composite thrombotic outcome of pump thrombus, ischemic cerebrovascular accidents, pulmonary embolism, and deep venous thrombosis.

DESIGN

Retrospective cohort study.

SETTING

Academic hospital.

PARTICIPANTS

Three hundred nineteen consecutive patients who underwent LVAD implantation (December 1, 2009 to December 30, 2018).

INTERVENTION

FEIBA administered to control perioperative hemorrhage.

MEASUREMENTS AND MAIN RESULTS

The 82 patients (25.7%) in the FEIBA cohort had more risk factors for perioperative hemorrhage, such as lower preoperative platelet count (169 ± 66 v 194 ± 68 × 10³/mL, p = 0.004), prior cardiac surgery (36.6% v 21.9%, p = 0.008), and longer cardiopulmonary bypass (CPB) time (100.3 v 75.2 minutes, p = 0.001) than the 237 controls. After 16.6 units (95% CI: 14.3-18.9) of blood products were given, 992 units (95% CI: 821-1163) of FEIBA were required to control bleeding in the FEIBA cohort. Compared to the controls, there were no differences in the 14-day composite thrombotic outcome (11.0% v 7.6%, p = 0.343) or mortality rate (3.7% v 1.3%, p = 0.179). Multivariate logistical regression identified preoperative international normalized ratio (odds ratio [OR]: 1.30, 95% CI: 1.04-1.62) and CPB time (OR: 1.11, 95% CI: 1.02-1.20) as risk factors for 14-day thrombotic events, but FEIBA usage was not associated with an increased risk.

CONCLUSIONS

In this retrospective cohort study, the use of FEIBA (∼1,000 units, ∼13 units/kg) to control perioperative hemorrhage following LVAD implantation was not associated with increases in mortality or composite thrombotic outcome.

Creation and Validation of a Novel Sex-Specific Mortality Risk Score in LVAD Recipients

Background

Prior studies have shown that women have worse 3‐month survival after receiving a left ventricular assist device compared with men. Currently used prognostic scores, including the Heartmate II Risk Score, do not account for the increased residual risk in women. We used the IMACS (International Society for Heart and Lung Transplantation Mechanically Assisted Circulatory Support) registry to create and validate a sex‐specific risk score for early mortality in left ventricular assist device recipients.

Methods and Results

Adult patients with a continuous‐flow LVAD from the IMACS registry were randomly divided into a derivation cohort (DC; n=9113; 21% female) and a validation cohort (VC; n=6074; 21% female). The IMACS Risk Score was developed in the DC to predict 3‐month mortality, from preoperative candidate predictors selected using the Akaike information criterion, or significant sex × variable interaction. In the DC, age, cardiogenic shock at implantation, body mass index, blood urea nitrogen, bilirubin, hemoglobin, albumin, platelet count, left ventricular end‐diastolic diameter, tricuspid regurgitation, dialysis, and major infection before implantation were retained as significant predictors of 3‐month mortality. There was significant ischemic heart failure × sex and platelet count × sex interaction. For each quartile increase in IMACS risk score, men (odds ratio [OR], 1.86; 95% CI, 1.74–2.00; P<0.0001), and women (OR, 1.93; 95% CI, 1.47–2.59; P<0.0001) had higher odds of 3‐month mortality. The IMACS risk score represented a significant improvement over Heartmate II Risk Score (IMACS risk score area under the receiver operating characteristic curve: men: DC, 0.71; 95% CI, 0.69–0.73; VC, 0.69; 95% CI, 0.66–0.72; women: DC, 0.73; 95% CI, 0.70–0.77; VC, 0.71 [95% CI, 0.66–0.76; P<0.01 for improvement in receiver operating characteristic) and provided excellent risk calibration in both sexes. Removal of sex‐specific interaction terms resulted in significant loss of model fit.

Conclusions

A sex‐specific risk score provides excellent risk prediction in LVAD recipients.

Device-Induced Hemostatic Disorders in Mechanically Assisted Circulation

Mechanically assisted circulation (MAC) sustains the blood circulation in the body of a patients undergoing cardiac surgery with cardiopulmonary bypass (CPB) or on ventricular assistance with a ventricular assist device (VAD) or on extracorporeal membrane oxygenation (ECMO) with a pump-oxygenator system. While MAC provides short-term (days to weeks) support and long-term (months to years) for the heart and/or lungs, the blood is inevitably exposed to non-physiological shear stress (NPSS) due to mechanical pumping action and in contact with artificial surfaces. NPSS is well known to cause blood damage and functional alterations of blood cells. In this review, we discussed shear-induced platelet adhesion, platelet aggregation, platelet receptor shedding, and platelet apoptosis, shear-induced acquired von Willebrand syndrome (AVWS), shear-induced hemolysis and microparticle formation during MAC. These alterations are associated with perioperative bleeding and thrombotic events, morbidity and mortality, and quality of life in MCS patients. Understanding the mechanism of shear-induce hemostatic disorders will help us develop low-shear-stress devices and select more effective treatments for better clinical outcomes.

Perioperative Management of Severe Acquired Coagulopathy in Patients with Left Ventricular Assist Device—a Literature Review and Expert Recommendations

Purpose of This Review

The implantation of a left ventricular assist device (LVAD) is associated with high hemorrhage-related re-exploration rates. Improved management of coagulopathy may improve patient outcome. The optimal management of acquired coagulopathy in LVAD patients needing urgent non-cardiac surgery needs to be defined. We aim to review risk factors for perioperative bleeding and diagnosis and management of LVAD-associated coagulopathy and to provide expert recommendations for clinical practice.

Recent Findings

In patients undergoing LVAD implantation, the severity of coagulopathy is directly related to the severity of the cardiac failure. The evidence from current literature for optimal management of acquired coagulopathy during and after LVAD implantation is sparse. The traditional transfusion strategy of replacing coagulation factors with fresh frozen plasma involves the risk of transfusion-associated circulatory overload. Current recommendations for targeted replacement of coagulation factors with 4-factor prothrombin concentrate and fibrinogen concentrate in cardiac surgery may be translated in this special setting.

Summary

The targeted, point-of-care use of concentrated coagulation factors may improve treatment of severe acquired coagulopathy during LVAD implantation and in LVAD patients needing urgent non-cardiac surgery.

Predictors of perioperative bleeding in left ventricular assist device implantation

Study objective

Early bleeding is a common source of morbidity associated with left ventricular assist device (LVAD) implantation. Our objective was to identify potential predictors of peri-implant bleeding.

Methods

We conducted a retrospective cohort study of LVAD implants at our institution between January 2010 and November 2018. A total of 210 patients were included. Data were collected for the duration of implant hospitalization, including perioperative invasive hemodynamics, echocardiography and operative details, antiplatelet and anticoagulant use, bleeding events and blood product use, and thromboembolic events. Peri-operative bleeding was defined as a transfusion requirement of >4 units of packed red blood cells in the intraoperative and first 7 days postoperative period, or a major 7-day post-implant overt bleeding event requiring procedural intervention.

Results

Perioperative bleeding occurred in 32% of patients and required surgical re-exploration in 9%. Multivariable logistic regression analysis identified history of previous sternotomy (OR 2.63, 95% CI 1.29 to 5.35, p-value 0.008), preoperative glomerular filtration rate <60 ml/min (OR 2.58, 95% CI 1.34 to 4.94, p-value 0.004), preoperative right atrial pressure >13 mm Hg (OR 2.36, 95% CI 1.19 to 4.67, p-value 0.014) and concomitant tricuspid valve repair (OR 2.48, 95% CI 1.23 to 5.01, p-value 0.011) as independent predictors of perioperative bleeding. In-hospital thromboembolic events occurred in 5% of patients, but there were no significant predictors for them.

Conclusions

Elevated right atrial pressure appears to be a reversible risk factor for early bleeding that should be targeted during pre-implant optimization of LVAD candidates.

Incidence, Factors, and Prognostic Impact of Re-Exploration for Bleeding After Continuous-Flow Left Ventricular Assist Device Implantation - A Japanese Single-Center Study

BACKGROUND

Continuous-flow left ventricular assist device (CF-LVAD) substantially improves survival in endstage heart failure patients. However, bleeding complications are common after CF-LVAD implantation and in some cases, re-exploration for bleeding is needed. We aimed to investigate the incidence, timing, and risk factors of bleeding requiring re-exploration after CF-LVAD implantation.

METHODS AND RESULTS

We retrospectively reviewed 162 consecutive patients (age 43±13 years, 71% men) who underwent CF-LVAD implantation (HeartMateII 119, Jarvik2000 15, HVAD 13, EVAHEART 10, DuraHeart 5) from January 2012 to June 2019. During follow-up [median 662 days, interquartile range (IQR) 364-1,116 days], 35 (21.6%) experienced re-exploration for bleeding. The median timing of re-exploration was 6 (IQR 1-10) days. In the multivariate logistic regression analysis, postoperative platelet count was an independent predictor for re-exploration for bleeding after CF-LVAD implantation (per 104/μL: odds ratio 0.83, 95% confidence interval 0.74-0.93, P=0.002). Patients who experienced re-exploration for bleeding had a significantly worse survival rate than patients who did not (at 4 years, 73.6% vs. 90.1%, P=0.039).

CONCLUSIONS

Re-exploration for bleeding is prevalent after CF-LVAD implantation, especially in patients with low postoperative platelet counts. As bleeding requiring re-exploration is associated with poor prognosis, risk stratification using the postoperative platelet count may be beneficial for these patients.

Acute Pump Thrombosis in the Early Postoperative Period After HeartMate 3 Implantation

There are no reports of acute pump thrombosis in the latest, continuous flow left ventricular assist devices type HeartMate 3, other than thrombus ingestion. We present a case of early thrombosis of the pump and outflow graft, necessitating acute pump and outflow graft replacement. A combination of low-flow episodes and subtherapeutic levels of anticoagulation was the most likely cause.

Bleeding in critical care associated with left ventricular assist devices: pathophysiology, symptoms, and management

Chronic heart failure (HF) is a growing health problem, and it is associated with high morbidity and mortality. Left ventricular assist devices (LVADs) are nowadays an important treatment option for patients with end-stage HF not only as a bridging tool to heart transplantation but also, as a permanent therapy for end-stage HF (destination therapy). The use of LVAD is associated with a high risk for bleeding complications and thromboembolic events, including pump thrombosis and ischemic stroke. Bleeding is the most frequent complication, occurring in 30% to 60% of patients, both early and late after LVAD implantation. Although the design of LVADs has improved over time, bleeding complications are still the most common complication and occur very frequently. The introduction of an LVAD results in an altered hemostatic balance as a consequence of blood-pump interactions, changes in hemodynamics, acquired coagulation abnormalities, and the strict need for long-term anticoagulant treatment with oral anticoagulants and antiplatelet therapy. LVAD patients may experience an acquired coagulopathy, including platelet dysfunction and impaired von Willebrand factor activity, resulting in acquired von Willebrand syndrome. In this educational manuscript, the epidemiology, etiology, and pathophysiology of bleeding in patients with LVAD will be discussed. Because hematologist are frequently consulted in cases of bleeding problems in these individuals in a critical care setting, the observed type of bleeding complications and management strategies to treat bleeding are also reviewed.

Independent risk factors for ICU mortality after left ventricular assist device implantation

Left ventricular assist devices (LVADs) are used as an alternative therapy for heart transplantation in patients with advanced heart failure. However, the mortality rate of these patients remains relatively high. A large proportion of deaths after LVAD implantation occur during intensive care unit (ICU) stay. We conducted a retrospective study to identify the risk factors for all-cause ICU mortality in patients with an implanted LVAD. Between January 1, 2008 and December 31, 2016, 70 consecutive patients who had received an LVAD were analyzed. The median ICU length of stay was 14 days (IQR: 8-31) and 16 patients (22.9% [95%CI: 13.1-32.7]) died in the ICU. The 90-day mortality rate was 25.7% (95%CI: 15.5-35.9). The main causes of ICU mortality were: multiple organ failure, stroke, and hemorrhagic events. The univariate analysis identified the following perioperative risk factors for all-cause ICU mortality: hypertension, preoperative platelet count, preoperative white cell count, inotropic support before LVAD implantation, mechanical ventilation before LVAD implantation, renal replacement therapy before LVAD implantation, short-term mechanical support before LVAD implantation, INTERMACS class 1 to 2, low intraoperative platelet count, low early postoperative hemoglobin level, low early postoperative platelet count, low early postoperative pH, and massive perioperative blood transfusion. In the multivariate logistic regression analysis, only mechanical ventilation before LVAD implantation was retained as an independent risk factor for ICU mortality (OR = 11.96 [95%CI: 2.67-53.45], P < .01). These findings confirm that most deaths after LVAD implantation occur in the ICU. Patients that receive mechanical ventilation preoperatively have the highest risk of death. This confirms the need to actively treat respiratory failure and to wean patients from respiratory support before LVAD implantation. Such a strategy offers the best opportunity to initiate active rehabilitation.

Acute kidney injury following left ventricular assist device implantation: Contemporary insights and future perspectives

Currently, an increasing number of patients with end-stage heart failure are being treated with left ventricular assist device (LVAD) therapy as bridge-to-transplantation, bridge-to-candidacy, or destination therapy (DT). Potential life-threatening complications may occur, specifically in the early post-operative phase, which positions LVAD implantation as a high-risk surgical procedure. Acute kidney injury (AKI) is a frequently observed complication after LVAD implantation and is associated with high morbidity and mortality. The rapidly growing number of LVAD implantations necessitates better approaches of identifying high-risk patients, optimizing peri-operative management, and preventing severe complications such as AKI. This holds especially true for those patients receiving an LVAD as DT, who are typically older (with higher burden of comorbidities) with impaired renal function and at increased post-operative risk. Herein we outline the definition, diagnosis, frequency, pathophysiology, and risk factors for AKI in patients with an LVAD. We also review possible strategies to prevent and manage AKI in this patient population.

Predicting Transfusions During Left Ventricular Assist Device Implant

Perioperative bleeding and transfusion cause morbidity and mortality in patients receiving left ventricular assist devices (LVADs). We assessed factors associated with transfusions within 30 days of durable LVAD implantation and the clinical outcomes associated with transfusions. A retrospective cohort study of patients undergoing initial durable LVAD implantation between 2014 and 2016 was performed. Rates of packed red blood cell (PRBC) or other blood product transfusions (platelets or fresh frozen plasma) were assessed. Ordinal multivariable regression analysis was performed to determine factors independently associated with transfusion. Analysis included 156 patients, mean age 54.6 years and 74.4% male, who received a mean of 11.7 units of PRBC and 10.0 units of other products within 30 days. Preimplant mechanical ventilation, dialysis, higher INR, previous sternotomy, higher model for end-stage liver disease score, and lower hemoglobin were associated with increased PRBC transfusion rates. Higher preoperative central venous pressure, mechanical ventilation, concomitant surgical procedures, previous sternotomy, and lower hemoglobin were associated with increased PRBC transfusion rates within 48 hours of implant (adjusted odds ratio [OR] 1.46, P = 0.013 per 5 mm Hg). There were no significant associations with ferritin (adjusted OR 1.00, P = 0.236) or transferrin saturation (adjusted OR 1.17, P = 0.068). Transfusions were associated with an increase in ventilation duration, intensive care unit length of stay, reoperation for bleeding, and all-cause mortality. In patients undergoing LVAD implantation, perioperative blood product exposure is common and associated with increased morbidity and mortality. Elevated central venous pressure and anemia are potentially modifiable factors associated with increased early PRBC transfusion rates.