Preoperative Atrial Fibrillation Increases Risk of Thromboembolic Events After Left Ventricular Assist Device Implantation

Atrial fibrillation increases thrombogenicity of LVAD therapy

BACKGROUND

This study investigates the hypothesis that presence of atrial fibrillation (AF) in LVAD patients increases thrombogenicity in the left ventricle (LV) and exacerbates stroke risk.

METHODS

Using an anatomical LV model implanted with an LVAD inflow cannula, we analyze thrombogenic risk and blood flow patterns in either AF or sinus rhythm (SR) using unsteady computational fluid dynamics (CFD). To analyze platelet activation and thrombogenesis in the LV, hundreds of thousands of platelets are individually tracked to quantify platelet residence time (RT) and shear stress accumulation history (SH).

RESULTS

The irregular and chaotic mitral inflow associated with AF results in markedly different intraventricular flow patterns, with profoundly negative impact on blood flow-induced stimuli experienced by platelets as they traverse the LV. Twice as many platelets accumulated very high SH in the LVAD + AF case, resulting in a 36% increase in thrombogenic potential score, relative to the LVAD + SR case.

CONCLUSIONS

This supports the hypothesis that AF results in unfavorable blood flow patterns in the LV adding to an increased stroke risk for LVAD + AF patients. Quantification of thrombogenic risk associated with AF for LVAD patients may help guide clinical decision-making on interventions to mitigate the increased risk of thromboembolic events.

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.

Left atrial appendage occlusion in ventricular assist device patients to decrease thromboembolic events: A computer simulation study

Atrial fibrillation (AF) is a common comorbidity in left ventricular assist device (LVAD) patients and has been identified as a risk factor for thromboembolic stroke. Blood stagnation within the left atrial appendage (LAA) is considered a possible major source of thrombosis and clinical studies have shown reduced thromboembolic risk after LAA occlusion (LAAO). Therefore, this study aims to investigate the effect of LAAO on thrombosis-related parameters using patient-specific simulations. Left ventricular and left atrial geometries of an LVAD patient were obtained from computed tomography and combined with hemodynamic data with either sinus rhythm (SR) or AF generated by a lumped parameter model. In four simulations applying contractile walls, stagnation volume and blood residence times were evaluated with or without AF and with or without LAAO. Reduced atrial contraction in AF resulted in unfavorable flow dynamics within the left atrium. The average atrial velocity was lower for the AF simulation when compared to SR, resulting in a 55% increase in the atrial stagnation volume (from 4.2 to 6.5 cm³). Moreover, blood remained in the LAA for more than 8 cardiac cycles. After LAAO the atrial stagnation decreased from 4.2 to 1.4 cm³ for SR and from 6.5 to 2.3 cm³ for the AF simulation. A significant stagnation volume was found in the LAA for both SR and AF, with larger values occurring with AF. These regions are known as potential sources for thrombus formation and can be diminished by LAAO. This significantly improved the thrombus-related flow parameters and may also lower the risk of thromboembolic events from the appendage.

Preoperative atrial fibrillation predicts worse outcomes after LVAD implantation

Introduction: Left ventricular assist device (LVAD) implantation is a common therapy for end-stage heart failure. Heart failure patients often present with atrial fibrillation (AF). The purpose of this study was to evaluate the influence of preoperative AF as well as vascular complications on outcome in LVAD patients. Methods: Between 01/2010 and 12/2017, 168 patients (141 male) with end-stage heart failure underwent LVAD implantation at a single center. Patient outcome was retrospectively studied by using the Kaplan-Meier method for analyzing crude survival as well as Cox regression for analyzing risk factors. Results: Sixty-two patients suffered from preoperative atrial fibrillation at LVAD implantation. Mean age was 56.8±11.9 years (range: 22–79) and 141 (84%) were male. Postoperative vascular or visceral surgical management due to malperfusion was needed in 27 patients (16.1%) and did not correlate with postoperative mortality (P=0.121, HR=1.587, CI=0.885–2.845). Patients with preoperative AF had a worse outcome in the Kaplan-Meier analysis (P=0.069). In contrast, cox regression showed that postoperative AF could not to be considered to be an independent predictor of mortality in this study group. Conclusion: Our data suggest that preoperative AF may be a potential predictor of mortality and impaired long-term outcome in LVAD patients. In contrast, preoperative ECLS and vascular or visceral surgery after LVAD implantation did not represent limiting factors with regard to mortality after LVAD implantation.

Rate Control Versus Rhythm Control in Patients with Left Ventricular Assist Devices and Atrial Fibrillation

Background

Atrial fibrillation (AF) is a common comorbidity in patients with left ventricular assist devices (LVAD) with no defined guideline treatment strategy of rate versus rhythm control. The purpose of this study is to determine the effects of rate versus rhythm control for AF on the outcomes of patients with LVAD at our institution.

Methods

Consecutive patients who underwent LVAD implantation at St Vincent Hospital from January 1, 2015 to December 31, 2017 were retrospectively evaluated. Patients with AF were identified and divided into rate control or rhythm control groups. The primary outcome evaluated was a composite of death, heart failure admission, gastrointestinal bleed, ventricular tachycardia, cerebrovascular accident, hemolysis, and pump thrombosis. Secondary outcomes included the individual variables from the primary outcome.

Results

Out of 201 patients that underwent LVAD implantation, 81 had AF after implantation and were included with a median follow-up period of 384 days. The rate control group (n = 31; 38%) and the rhythm control group (n = 51; 62%) had no difference in composite outcomes (61% vs 59%, p = 0.83). When taken individually there was no difference in outcomes between the two groups. Thirteen patients underwent electrical cardioversion and successful conversion to normal sinus rhythm occurred in 71% of cases with a 60% recurrence rate.

Conclusions

There was no difference in primary outcome between rate and rhythm control groups. These data suggest that maintenance of sinus rhythm may not be necessary in all patients with LVAD.

Smoking and the Risk of Stroke in Patients with a Left Ventricular Assist device

There are limited data on the association of smoking with the risk of stroke following left ventricular assist device (LVAD) implantation. We designed this study to analyze the impact of smoking status at the time of LVAD implantation on stroke. We hypothesized that current smokers are at increased risk of stroke when compared with patients who were former or never smokers. The study population comprised of 369 patients in the University of Rochester Medical Center LVAD database, implanted with an LVAD between 2008 and 2018. Patients were stratified as current smoker (smoking within 30 days before LVAD implantation), former smoker, and never smoker. Stroke was defined as a transient ischemic attack or cerebrovascular accident (hemorrhagic or ischemic). There were 45 current smokers, 198 former smokers, and 125 never smokers. Current smokers were younger (mean age 50 ± 11 years), as compared with former (58 ± 12 years) and never smokers (56 ± 13 years) p < 0.001. At 2 years following LVAD implantation, the cumulative incidence of stroke was significantly higher among current smokers (39%) as compared with former and never smokers (16% and 15%, respectively; p = 0.022 for the overall difference during follow-up). In a multivariate model adjusted for significant clinical variables, current smoking was associated with a significant 88% (p = 0.018) higher risk of stroke when compared with all noncurrent smokers. In conclusion, our data suggest that LVAD candidates who are current smokers experience a significantly higher risk of stroke following device implantation.

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.

Antiplatelet and anticoagulation strategies for left ventricular assist devices

Left ventricular assist devices (LVAD) have revolutionized the management of advanced heart failure. However, complications rates remain high, among which hemorrhagic and thrombotic complications are the most important. Antiplatelet and anticoagulation strategies form a cornerstone of LVAD management and may directly affect LVAD complications. Concurrently, LVAD complications influence anticoagulation and anticoagulation management. A thorough understanding of device, patient, and management, including anticoagulation and antiplatelet therapies, are important in optimizing LVAD outcomes. This article provides a comprehensive state of the art review of issues related to antiplatelet and anticoagulation management in LVADs. We start with a historical overview, the epidemiology and pathophysiology of bleeding and thrombotic complications in LVADs. We then discuss platelet and anticoagulation biology followed by considerations prior to, during, and after LVAD implantation. This is followed by discussion of anticoagulation and the management of thrombotic and hemorrhagic complications. Specific problems, including management of heparin-induced thrombocytopenia, anticoagulant reversal, novel oral anticoagulants, artificial heart valves, and noncardiac surgeries are covered in detail.

Percutaneous Ventricular Assist Device vs. Intra-Aortic Balloon Pump for Hemodynamic Support in Acute Myocardial Infarction-Related Cardiogenic Shock and Coexistent Atrial Fibrillation: A Nationwide Propensity-Matched Analysis'

BACKGROUND

Patients suffering an acute myocardial infarction complicated by cardiogenic shock (AMICS) may experience clinical deterioration with concomitant atrial fibrillation (AF). Recent data suggest that percutaneous ventricular assist devices (pVADs) provide superior hemodynamic support over intra-aortic balloon pump (IABP) in AMICS. In patients with AF+AMICS, however, outcomes data comparing these two devices remain limited.

METHODS

Using the National Inpatient Sample datasets (2008-2014) and a propensity-score matched analysis, we compared the outcomes of AMICS+AF hospitalized patients undergoing PCI with pVAD vs. IABP support.

RESULTS

A total of 12,842 AMICS+AF patients were identified (pVAD=468, IABP=12,374). The matched groups (pVAD=443, IABP=443) were comparable in terms of mean age (70.3 ± 12.0 vs. 70.4 ± 11.0yrs, p = 0.92). The utilization of pVAD was higher in whites but lower in Medicare/Medicaid beneficiaries as compared to IABP. The pVAD group demonstrated higher rates of obesity (13.6% vs. 7.8%, p = 0.006) and dyslipidemia (48.4% vs. 41.8%, p = 0.05). There was no difference in the in-hospital mortality (40.5% vs. 36.8%, p = 0.25); however, pVAD group had a lower incidence of post-procedural MI and higher incidences of stroke (7.8% vs. 4.4%, p = 0.03), hemorrhage (5.6% vs. 2.3%, p = 0.01), discharges to home health care (13.5% vs. 10.1%, p<0.001) and to other facilities (29.1% vs. 24.9%, p<0.001) as compared to IABP group. There was no difference between the groups in terms of mean length of stay or hospital charges.

CONCLUSIONS

All-cause inpatient mortality was similar in AMICS+AF patients undergoing PCI who were treated with either pVAD or IABP. The pVAD group, however, experienced more complications while consuming greater healthcare resources.

Atrial arrhythmias in patients with left ventricular assist devices

PURPOSE OF REVIEW

Atrial arrhythmias commonly occur in patients with advanced heart failure with reduced ejection fraction (HFrEF) who require left ventricular assist devices (LVADs) implantation. This review summarizes the current literature regarding the incidence, prevalence, and predictors of atrial arrhythmias in LVAD patients and its impact on the clinical outcomes. Moreover, we review the mechanisms and management strategies of atrial arrhythmias in this population.

RECENT FINDINGS

Atrial arrhythmias including atrial fibrillation, atrial flutter, and atrial tachycardia are highly prevalent in patients with advanced HFrEF before or after the LVAD implantation. Atrial arrhythmias have a significant impact on overall clinical outcome including survival, heart failure hospitalization, quality of life, thromboembolic events and resource utilization. Atrial fibrillation and other atrial arrhythmias frequently coexist in this population. In patients with atrial arrhythmias and LVAD, anticoagulation and cardiovascular implantable electronic devices should be closely monitored and managed to prevent thromboembolic events or inappropriate shocks. Rhythm and rate control strategies are comparable regarding overall clinical outcomes in this population. LVADs induce favorable atrial remodeling in patients with HFrEF.

SUMMARY

Atrial arrhythmias are highly common in LVAD patients and have significant impact on overall clinical outcomes. Further studies are needed to determine optimal management and prevention of atrial arrhythmias in LVAD population.

Insight into Atrial Fibrillation in LVAD Patients: From Clinical Implications to Prognosis

The use of left ventricular assist devices (LVADs), whether for destination therapy or bridge to transplantation, has gained increasing validation in recent years in patients with advanced heart failure. Arrhythmias can be the most challenging variables in the management of such patients but the main attention has always been focused on ventricular arrhythmias given the detrimental impact on mortality. Nevertheless, atrial fibrillation (AF) is the most common rhythm disorder associated with advanced heart failure and may therefore characterize the LVADs' pre- and postimplantation periods. Indeed, the consequences of AF in the population suffering from standard heart failure may require a more comprehensive evaluation in the presence of or in sight of an LVAD, making the AF clinical management in these patients potentially complex. Several studies have been based on this subject with different and often conflicting results, leaving many questions unresolved. The purpose of this review is to summarize the main pieces of evidence about the clinical impact of AF in LVAD patients, underlining the main implications in terms of hemodynamics, thromboembolic risk, bleeding and prognosis. Therapeutic considerations about the clinical management of these patients are also made according to the latest evidence.

The Impact of Atrial Fibrillation on In-Hospital Outcomes in Patients With Acute Myocardial Infarction Complicated by Cardiogenic Shock Undergoing Coronary Revascularization with Percutaneous Ventricular Assist Device Support

Background

Atrial fibrillation (AF) is common in acute myocardial infarction complicated by cardiogenic shock (AMI-CS) requiring percutaneous ventricular assist device (pVAD-Impella®) support during percutaneous coronary interventions (PCI). We evaluated the effects of a coexistent diagnosis of AF on clinical outcomes in patients with AMI-CS undergoing PCI with pVAD support.

Methods

The National Inpatient Sample (2008-2014) was queried to identify patients with AMICS requiring PCI with pVAD support and had a concomitant diagnosis of AF. Propensity-matched cohorts (AF+ vs AF-) were compared for in-hospital outcomes.

Results

A total of 840 patients with AMICS requiring PCI with pVAD support (420 AF+ vs 420 AF-) were identified in the matched cohort. Patients with AF were older (mean 69.7±12.0 vs 67.9±11.3 yrs, p=0.030). All-cause in-hospital mortality rates between the two groups were similar (40.5% vs 36.7%, p=0.245); however, higher postprocedural respiratory complications (9.5% vs 4.8%, p=0.007) were seen in AF+ group. In-hospital cardiac arrests were more frequent in the AF- group (32.0% vs 19.2%, p<0.001). We examined the length of stay (LOS), transfer to other facilities, and hospital charges as metrics of health care resource consumption and found that the AF+ cohort experienced fewer routine discharges (13.1% vs 30.2%), more frequent transfers to other facilities including skilled nursing facilities or intermediate care facilities (27.3% vs 17.8%; p<0.001), more frequently required the use of home health care (14.3% vs 7.1%; p<0.001). The mean LOS (11.9±10.1 vs 9.11±6.8, p<0.001) and hospital charges ($308,478 vs $277,982, p=0.008) were higher in the AF+ group.

Conclusions

In patients suffering AMICS requiring PCI and pVAD support, a coexistent diagnosis of AF was not associated with an increase in all-cause in-hospital mortality as compared to patients without AF. However, healthcare resource consumption as assessed by various metrics was consistently greater in the AF+ group.

Impact of Atrial Fibrillation on In-Hospital Mortality and Thromboembolic Complications after Left Ventricular Assist Device Implantation

The association between atrial fibrillation (AF) and thromboembolic (TE) complications in left ventricular assist device (LVAD) recipients is controversial, and there is paucity of large-scale data evaluating the impact of AF on early outcomes after device implantation. Using the National Inpatient Sample, we identified hospitalizations where patients underwent LVAD implantation from 2010 to 2015. Multivariate logistic regression was used to evaluate the association of AF on in-hospital outcomes. A total of 18,378 patients (41.7% with AF) underwent LVAD implantation. Patients with AF were older (59.9 vs. 54.0 years, p < 0.001), more commonly male (79.9 vs. 74.1%, p < 0.001), and had a greater burden of comorbidities as measured by the Elixhauser comorbidity index (7.2 vs. 6.3, p < 0.001). Patients with AF had less incidence of ischemic stroke (3.1 vs. 4.7%, p = 0.04, OR 0.68), hemorrhagic stroke (1.0 vs. 2.4%, p = 0.006, OR 0.43), and other systemic embolism (1.8 vs. 3.7%, p = 0.01, OR 0.55). There was no significant difference in the incidence of bleeding requiring transfusion between AF and no AF cohorts (29.3 vs. 24.2%, p = 0.09, OR 1.15). LOS was shorter in patients with AF (32.9 vs. 36.7 mean days, p < 0.001). Patients with AF had lower in-hospital mortality (8.9 vs. 14.9%, p < 0.001, OR 0.48). In a large real-world US cohort of patients undergoing LVAD implantation, a diagnosis of AF was common among device recipients. After adjustment for demographics and comorbidities, AF was associated with reduced TE events and in-hospital mortality.

Impact of preoperative atrial fibrillation on thromboembolic events and pump thrombosis in long-term left ventricular assist device therapy

OBJECTIVES

Pump thrombosis (PT) and thromboembolic events (TEs) remain major adverse events in left ventricular assist device (LVAD) therapy at an annual rate of 6-8% supported with the HeartWare HVAD and HeartMate II. PT and TEs are multifactorial events. Understanding the predisposing risk factors for PT and TE is paramount to define preventive strategies. Preoperative atrial fibrillation (AF) is considered a significant and potentially modifiable risk factor. This study investigates whether LVAD patients with AF exhibit a higher rate of PT and TE than those in sinus rhythm (SR).

METHODS

We evaluated medical records of consecutive patients who underwent implantation of the HeartMate II (n = 195; 25.4%) and HeartWare HVAD (n = 574; 74.6%) at our institution between 2006 and 2015. Only visually confirmed PT was included in the study. TE was defined as any peripheral embolism or cerebral embolism according to the INTERMACS definitions.

RESULTS

SR was documented preoperatively in 211 patients (SR group) and AF in 558 patients (AF group). The median duration of support was 0.78 years in the AF group and 1.03 years in the SR group. The mean age was 60.27 years in the AF group and 52.04 years in the SR group. In the AF group, 83.0% of the patients were male, compared to 77.3% in the SR group. The cumulative incidence of PT in the SR group was 2.5% [95% confidence interval (CI) 0.3-4.7%] after 1 year and 5.7% (95% CI 2.2-9.2%) after 2 years, and in the AF group 4.9% (95% CI 3.0-6.7%) and 7.8% (95% CI 5.4-10.2%), respectively (P = 0.129). TEs were recorded in the SR group in 4.4% (95% CI 1.6-7.2%) after 1 year and in 6.3% (95% CI 2.8-9.8%) after 2 years, and occurred after a median support time of 214 days (range 120-768). In the AF group, the cumulative incidence was 8.4% (95% CI 6.0-10.7%) and 10.7% (95% CI 8.0-13.4%), respectively, after a median support time of 116 days (range 37-375), P-value = 0.163. In the multivariate analysis, event-free survival was not influenced by the preoperative SR [hazard ratio (HR) 0.86, 95% CI 0.68-1.1; P = 0.19].

CONCLUSIONS

Our study showed that the preoperative rhythm has no impact on survival, PT and TEs despite different preoperative risk factor profiles in the AF and SR group. Thus, the effect of a maze procedure, catheter ablation or left atrial appendage closure on PT and TE's for AF patients during LVAD implantation is questionable. However, to obtain a definitive answer, a prospective study would be of value.

Computational Simulation of Cardiac Function and Blood Flow in the Circulatory System under Continuous Flow Left Ventricular Assist Device Support during Atrial Fibrillation

Prevalence of atrial fibrillation (AF) is high in heart failure patients supported by a continuous flow left ventricular assist device (CF-LVAD); however, the long term effects remain unclear. In this study, a computational model simulating effects of AF on cardiac function and blood flow for heart failure and CF-LVAD support is presented. The computational model describes left and right heart, systemic and pulmonary circulations and cerebral circulation, and utilises patient-derived RR interval series for normal sinus rhythm (SR). Moreover, AF was simulated using patient-derived unimodal and bimodal distributed RR interval series and patient specific left ventricular systolic functions. The cardiovascular system model simulated clinically-observed haemodynamic outcomes under CF-LVAD support during AF, such as reduced right ventricular ejection fraction and elevated systolic pulmonary arterial pressure. Moreover, relatively high aortic peak pressures and middle arterial peak flow rates during AF with bimodal RR interval distribution, reduced to similar levels as during normal SR and AF with unimodal RR interval distribution under CF-LVAD support. The simulation results suggest that factors such as distribution of RR intervals and systolic left ventricular function may influence haemodynamic outcome of CF-LVAD support during AF.

Meta-Analysis of the Effect of Preoperative Atrial Fibrillation on Outcomes After Left Ventricular Assist Device Implantation

The effect of preoperative atrial fibrillation (AF) on clinical outcomes after left ventricular assist device (LVAD) implantation remains uncertain. We sought to conduct a meta-analysis to assess the safety and efficacy of LVAD implantation in AF patients. Medline and Scopus were searched for studies that assessed the effect of preoperative AF on clinical outcomes in patients who underwent LVAD implantation. Outcomes of interest included all-cause mortality, thromboembolic events, and bleeding. Estimates were combined using random effects model to calculate risk ratios (RRs) with 95% confidence intervals. In this meta-analysis of 7 studies including 5,658 patients, preoperative AF was not associated with increased risk of all-cause mortality at 30 days (RR = 0.84 [0.51, 1.37]; p = 0.49; I² = 0%), 6 months (RR = 1.17 [0.96, 1.14]; p = 0.11; I² = 21%), 1 year (RR = 1.16 [0.84, 1.60]; p = 0.37; I² = 53%) and 2 years (RR = 1.14 [0.96, 1.36]; p = 0.12; I² = 23%). Preoperative AF did not increase the risk of thromboembolism (RR = 0.86 [0.38, 1.92]; p = 0.71; I² = 26%), pump thrombosis (RR = 1.22 [0.88, 1.68]; p = 0.23; I² = 49%), stroke (RR = 1.02 [0.87, 1.19]; p = 0.79; I² = 11%), or major bleeding (RR = 0.86 [0.38, 1.92]; p = 0.71; I² = 26%) after LVAD implantation. However, AF was associated with significantly increased risk of gastro-intestinal bleeding in patients receiving LVADs (RR = 1.27 [1.05, 1.55]; p = 0.014; I² = 0%). In conclusion, this meta-analysis reports a significantly increased risk of gastrointestinal (GI) bleeding in LVADs recipients having concomitant AF. However, AF had no significant effect on all-cause mortality, stroke, or thromboembolic events in these patients. Further well-conducted studies are needed to validate these results.

Impact of preoperative atrial fibrillation in patients with left ventricular assist device: A systematic review and meta-analysis

Atrial fibrillation (AF) is a common finding in patients evaluated for left ventricular assist device (LVAD). There is conflicting data regarding the mortality risk as well as the thromboembolic risk in patients with preoperative AF who undergo LVAD implantation. We examined these risks by performing a meta-analysis. We performed a literature search of Pubmed, EMBASE, SCOPUS, and Cochrane from inception to February 2018. The eligible studies were used to compare mortality rate and thromboembolic risk between AF and Non-AF (NAF) groups after LVAD implantation. We obtained 391 articles from our search strategy. Seven retrospective studies were included and accounted for 5823 LVAD patients (AF 1589; NAF 4234). The median follow-up duration ranged from 7-24 months. The pooled analysis revealed a significantly increased risk of mortality in preoperative AF patients who underwent LVAD operation compared to those with NAF (Risk Ratio [RR] 1.16, 95% CI 1.05-1.28, I2 = 0%). Five studies reported thromboembolism events involving 1359 preoperative AF and 3893 NAF patients. The pooled analysis did not show a statistically significant association between risk of thromboembolic event and preoperative AF (Risk Ratio [RR] 1.08, 95% CI 0.86-1.36, I2 = 76.2%). Our study shows that preoperative AF may be associated with a higher mortality rate. This study is limited by the fact that the data are pooled from retrospective studies. Further prospective studies are warranted in order to validate these results.

Device Therapy and Arrhythmia Management in Left Ventricular Assist Device Recipients: A Scientific Statement From the American Heart Association

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure with reduced ejection fraction. Although these devices effectively improve survival, atrial and ventricular arrhythmias are common, predispose these patients to additional risk, and complicate patient management. However, there is no consensus on best practices for the medical management of these arrhythmias or on the optimal timing for procedural interventions in patients with refractory arrhythmias. Although the vast majority of these patients have preexisting cardiovascular implantable electronic devices or cardiac resynchronization therapy, given the natural history of heart failure, it is common practice to maintain cardiovascular implantable electronic device detection and therapies after LVAD implantation. Available data, however, are conflicting on the efficacy of and optimal device programming after LVAD implantation. Therefore, the primary objective of this scientific statement is to review the available evidence and to provide guidance on the management of atrial and ventricular arrhythmias in this unique patient population, as well as procedural interventions and cardiovascular implantable electronic device and cardiac resynchronization therapy programming strategies, on the basis of a comprehensive literature review by electrophysiologists, heart failure cardiologists, cardiac surgeons, and cardiovascular nurse specialists with expertise in managing these patients. The structure and design of commercially available LVADs are briefly reviewed, as well as clinical indications for device implantation. The relevant physiological effects of long-term exposure to continuous-flow circulatory support are highlighted, as well as the mechanisms and clinical significance of arrhythmias in the setting of LVAD support.

Incidence and Outcomes of Postoperative Atrial Fibrillation After Left Ventricular Assist Device

This study sought to determine the incidence, predictors, and outcomes of postoperative atrial fibrillation (POAF) in patients undergoing implantation of left ventricular assist devices (LVADs). A retrospective analysis of all patients who underwent LVAD implantation from 2013 to 2014 was conducted. Postoperative AF, survival, and thrombotic complications were evaluated after surgery. A total of 47 patients (mean age, 56.4 ± 12.5 years; 33 male) were included and followed for a median of 331 days. Within 30 days of surgery, 13 (28%) patients developed POAF at mean 7.9 ± 8.5 days. Obstructive lung disease was a predictor of POAF (p = 0.01). Postoperative AF was not associated with increased mortality, length of stay, or thrombotic complication within 30 days. Postoperative AF was predictive of recurrent new AF (24 vs. 5.5%) after 30 days of LVAD implantation. Also, POAF was associated with increased risk of ischemic stroke and device thrombosis during follow-up (p = 0.01). These results show that unlike in other cardiac surgery, POAF does not have a negative impact on early postoperative morbidity or mortality. However, POAF is a predictor for future AF, ischemic stroke, and device thrombosis.

Left Ventricular Assist Devices: How Do We Define Success?

Despite the growing acceptance of left ventricular assist device (LVAD) therapy to improve survival and quality of life in heart failure (HF) patients, uncertainties persist regarding the definition of a successful implant. We sought to define an innovative approach to assess success and subsequently compare preoperative variables affecting outcomes. From January 2007 to 2015, 278 patients underwent LVAD implantation. Median age at implant was 62 years and 81% patients were males. Indication for support was bridge-to-transplantation in 36% patients and the etiology of HF was ischemic in 49% patients. Based on clinically relevant and accepted standards, we defined successful LVAD implant as someone who was alive or transplanted at 2 years, had two or less readmissions in the first year, had no major adverse events in the first year, and had a New York Heart Association class of ≤ II at 6 months. Follow-up was obtained for a median of 1.7 years for a total of 605 patient-years-of-support. Based on our criteria, 81/278 (29%) patients were defined as having a successful implant. Univariate predictors of LVAD failure included destination therapy indication (hazard ratio [HR] = 2.11 [1.24, 3.58]), ischemic cardiomyopathy (HR = 1.73 [1.02, 2.94]), and a higher left ventricular ejection fraction (HR = 1.54 [1.07, 2.22]). After multivariable analysis, only destination therapy indication (HR = 2.2 [1.28, 3.78]) was found to be independently predictive of success failure. Despite an overall trend toward improved outcomes on device therapy, our criteria classified only one-third of patients as successful. Continued improvements in adverse event profiles, appropriate patient selection, and optimal time of implantation, together hold the key to improve outcomes after LVAD therapy.

Atrial Fibrillation in Patients with Heart Failure: Current State and Future Directions

Heart failure affects nearly 26 million people worldwide. Patients with heart failure are frequently affected with atrial fibrillation, and the interrelation between these pathologies is complex. Atrial fibrillation shares the same risk factors as heart failure. Moreover, it is associated with a higher-risk baseline clinical status and higher mortality rates in patients with heart failure. The mechanisms by which atrial fibrillation occurs in a failing heart are incompletely understood, but animal studies suggest they differ from those that occur in a healthy heart. Data suggest that heart failure-induced atrial fibrosis and atrial ionic remodeling are the underlying abnormalities that facilitate atrial fibrillation. Therapeutic considerations for atrial fibrillation in patients with heart failure include risk factor modification and guideline-directed medical therapy, anticoagulation, rate control, and rhythm control. As recommended for atrial fibrillation in the non-failing heart, anticoagulation in patients with heart failure should be guided by a careful estimation of the risk of embolic events versus the risk of hemorrhagic episodes. The decision whether to target a rate-control or rhythm-control strategy is an evolving aspect of management. Currently, both approaches are good medical practice, but recent data suggest that rhythm control, particularly when achieved through catheter ablation, is associated with improved outcomes. A promising field of research is the application of neurohormonal modulation to prevent the creation of the "structural substrate" for atrial fibrillation in the failing heart.

INTERMACS Analysis of Stroke During Support With Continuous-Flow Left Ventricular Assist Devices: Risk Factors and Outcomes

OBJECTIVES

This study sought to evaluate predictors of stroke during left ventricular assist device (LVAD) support from data available prior to implantation, and quantify stroke-related morbidity and mortality.

BACKGROUND

Stroke is a major complication after LVAD. Pre-implant factors that influence stroke are not well understood.

METHODS

We evaluated all patients in INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) who were implanted with continuous flow LVADs from May 1, 2012, to March 31, 2015. Pre-operative risk factors for stroke and stroke incidence, morbidity, and mortality were analyzed.

RESULTS

During the study period, 7,112 patients underwent continuous flow LVAD placement. Median follow-up was 9.79 months (range 0.02 to 34.96 months). Of all patients, 752 (10.57%) had at least 1 stroke, with an incidence rate of 0.123 strokes per patient-year. A total of 447 (51.38%) strokes were ischemic and 423 (48.62%) were hemorrhagic. Patients with hemorrhagic stroke had worse survival than those with ischemic strokes (30-day survival: 45.3% vs. 80.7%; p < 0.001). Of patients with a first stroke, 13% had a second stroke. Pre-implant predictors of stroke were female sex (hazard ratio [HR]: 1.51; 95% confidence interval [CI]: 1.25 to 1.82; p < 0.001), pre-implant systolic blood pressure (HR: 1.01; 95% CI: 1.00 to 1.01; p = 0.002), heparin-induced thrombocytopenia (HR: 3.68; 95% CI: 1.60 to 8.47; p = 0.002), intra-aortic balloon pump (HR: 1.21; 95% CI: 1.01 to 1.46; p = 0.043), and primary cardiac diagnosis (ischemic/other/unknown) (p = 0.040).

CONCLUSIONS

Despite improvements in LVAD technology, stroke-related morbidity and mortality is substantial. Further investigation is necessary to decrease the risk of this devastating complication.

Left ventricular assist device exchange for the treatment of HeartMate II pump thrombosis

Background

Pump thrombosis is the most severe and acute complication of left ventricular assist device (LVAD) therapy and treatment remains challenging. Whilst lysis therapy is often not successful, the exchange of the occluded LVAD is currently the most applied therapeutic treatment for this event. With this study we examine the effects of minimal-invasive LVAD exchange on the rate re-thrombosis and outcomes as well as adverse events in the study group.

Methods

Between February 2004 and December 2015 more than 600 LVADs were implanted at our institution. We retrospectively studied a patient cohort of 41 patients who underwent LVAD exchange because of pump thrombosis at a single institution. Outcomes, rates of re-thrombosis and adverse events were analyzed.

Results

Between February 2004 and December 2015, 87 exchanges of LVADs were performed at a single center. In 41 cases pump thrombosis was the reason for LVAD exchange. A total of 28 patient years (10,276 days) were analyzed. Average ICU stay was 15.8±20.4 days and average in-hospital stay 38.1±37.3 days after LVAD exchange. After thirty days the survival rate was 80.5%, 75.6% after 6 months and 70.7% one year after LVAD exchange. Out of the study cohort, three patients have successfully undergone heart transplantation. Twelve patients suffered a stroke postoperatively (29%). Twelve patients needed postoperative dialysis (29%). No technical complications of the VAD were recorded in the study group. Two patients underwent successful LVAD explantation due to myocardial recovery. One year after LVAD exchange, 14 patients underwent re-exchange due to pump thrombosis (34%). Eight patients suffered from a LVAD related infection out of which two patients were treated by pump exchange. A total of 12 patients died during the complete one year follow up of this study (29%). Four patients died in the second, two in the third and one in the fourth year after LVAD exchange. The remaining 17 patients are still ongoing on the device.Conclusions: It is generally feasible to treat pump thrombosis via LVAD exchange. Yet, the exchange procedure is not without risk and the risk of re-thrombosis (34%), stroke (29%), postoperative dialysis (29%) and perioperative complications remains high.

Postoperative atrial fibrillation is associated with increased morbidity and resource utilization after left ventricular assist device placement

BACKGROUND

Postoperative atrial fibrillation (POAF) is a known risk factor for morbidity and mortality after cardiac surgery but has not been investigated in the left ventricular assist device (LVAD) population. We hypothesize that POAF will increase morbidity and resource utilization after LVAD placement.

METHODS

Records were extracted for all patients in a regional database who underwent continuous-flow LVAD placement (n = 1064, 2009-2017). Patients without a history of atrial fibrillation (n = 689) were stratified by POAF for univariate analysis. Multivariable regression models calculated the risk-adjusted association of arrhythmias on outcomes and resource utilization.

RESULTS

The incidence of new-onset POAF was 17.6%, and patients who developed POAF were older and more likely to have moderate/severe mitral regurgitation, a history of stroke, and concomitant tricuspid surgery. After risk adjustment, POAF was not associated with operative mortality or stroke but was associated with major morbidity (odds ratio [OR] 2.5 P = .0004), prolonged ventilation (OR 2.7, P < .0001), unplanned right ventricular assist device (OR 2.9, P = .01), and a trend toward renal failure (OR 2.0, P = .06). In addition, POAF was associated with greater risk-adjusted resource utilization, including discharge to a facility (OR 2.2, P = .007), an additional 4.9 postoperative days (P = .02), and 88 hours in the intensive care unit (P = .01).

CONCLUSIONS

POAF was associated with increased major morbidity, possibly from worsening right heart failure leading to increased renal failure and unplanned right ventricular assist device placement. This led to patients with POAF having longer intensive care unit and hospital stays and more frequent discharges to a facility.

Prevention and Treatment of Thrombotic and Hemorrhagic Complications in Patients Supported by Continuous-Flow Left Ventricular Assist Devices

PURPOSE OF REVIEW

The purpose of this review is to describe the current knowledge in prevention and treatment of thrombotic (pump thrombosis and ischemic stroke) and bleeding (gastrointestinal and hemorrhagic stroke) complications in patients supported by continuous-flow left ventricular assist devices (CF-LVAD).

RECENT FINDINGS

Left ventricular assist devices (LVADs) are now widely used for the management of end-stage heart failure. Unfortunately, in spite of the indisputable positive impact LVADs have on patients, the frequency and severity of complications are limitations of this therapy. Stroke, pump thrombosis, and gastrointestinal bleeding are among the most serious and frequent complications in these patients. The balance between hemorrhagic and thrombotic complications in patients supported with CF-LVAD is difficult as most patients do not necessarily fit a "bleeder" or a "clotter" profile but rather move from one side to the other of the thrombotic/bleeding spectrum. Further research is necessary to better understand the risk factors and mechanisms involved in the development of these complications.

Left Ventricular Assist Devices for Lifelong Support

Continuous-flow left ventricular assist devices (LVADs) have revolutionized advanced heart failure care. These compact, fully implantable heart pumps are capable of providing meaningful increases in survival, functional capacity, and quality of life. Implantation volumes continue to grow, but several challenges remain to be overcome before LVADs will be considered as the therapy of choice for all patients with advanced heart failure. They must be able to consistently extend survival for the long term (7 to 10 years), rather than the midterm (3 to 5 years) more typical of contemporary devices; they must incorporate design elements that reduce shear stress and avoid stasis to reduce the frequent adverse events of bleeding, stroke, and pump thrombosis; and they must become more cost-effective. The advancements in engineering, implantation technique, and medical management detailed in this review will highlight the progress made toward achieving lifelong LVAD support and the challenges that remain.

Relationship Between Anticoagulation Intensity and Thrombotic or Bleeding Outcomes Among Outpatients With Continuous-Flow Left Ventricular Assist Devices

BACKGROUND

We evaluated thrombotic and bleeding outcomes in patients with continuous-flow left ventricular assist devices (CF-LVADs), stratified by anticoagulation intensity. Previous studies of outpatients with CF-LVADs have suggested that target international normalized ratio (INR) values <2.5 (range, 2-3) may be used. However, recent studies reported an increase in pump thrombosis among CF-LVADs, especially within the first 6 months of implant.

METHODS AND RESULTS

We retrospectively reviewed 249 outpatients at our center who received a CF-LVAD between January 2005 and August 2013. Using Poisson models, we analyzed their 10 927 INRs to determine INR-specific rates of thrombotic (ischemic stroke and suspected pump thrombosis) and hemorrhagic (gastrointestinal bleeding and hemorrhagic stroke) events occurring outside of the hospital. In multivariate analyses, we adjusted for age, sex, atrial fibrillation, coronary disease, and LVAD type as time-dependent Cox proportional hazard models. During a mean follow-up of 17.6±13.6 months, thrombotic events occurred in 46 outpatients. The highest event rate (0.40 thrombotic events per patient-year) was in the INR range of <1.5, but INR values of 1.5 to 1.99 also had high rates (0.16 thrombotic events per patient-year). INR was inversely associated with thrombotic events (hazard ratio, 0.40; 95% confidence interval, 0.22-0.72; P=0.002). The optimal INR based on weighted mortality of thrombotic and bleeding events was 2.6.

CONCLUSIONS

INR is inversely related to thrombotic events occurring outside of the hospital among patients supported with CF-LVADs. INR values <2.0 increase the rate of thrombotic events occurring outside of the hospital among patients supported with CF-LVADs.

Atrial Arrhythmias and Electroanatomical Remodeling in Patients With Left Ventricular Assist Devices

BACKGROUND

The incidence, predictors, and impact of atrial arrhythmias along with left atrial structural changes in patients with left ventricular assist devices (LVADs) remain undetermined.

METHODS AND RESULTS

All patients who underwent LVAD implantation from 2008 to 2015 at the University of Chicago Medical Center were included. Electronic medical records, electrocardiograms, echocardiograms, and cardiac electrical device interrogations were reviewed. The association of arrhythmias and clinical covariates with survival was evaluated by Kaplan-Meier and Cox proportional hazards analyses. A total of 331 patients were followed for a median of 330 days (range 0-2306 days). Mean age was 57.8±12.8 years, 256 participants (77.3%) were male, mean left ventricular ejection fraction was 20±6.6%, and 124 (37.5%) had ischemic cardiomyopathy. Atrial arrhythmias (53.8%) were highly prevalent and frequently coexisted before LVAD implantation: atrial fibrillation (AF) in 45.9%, atrial flutter in 13.9%, atrial tachycardia in 6.9%, and atrioventricular nodal reentrant tachycardia in 1.2%. New-onset AF was documented in 14 patients (7.8% of patients without prior AF) after the first 30 days with an LVAD. Increasing age, renal insufficiency, and lung disease were predictors of new-onset AF after LVAD implantation. Of patients with paroxysmal AF, 43% had no further AF after LVAD. Left atrial size and volume index improved with LVAD (P<0.005). History of persistent AF, atrial tachycardia, ventricular arrhythmia, coronary artery bypass, and low albumin were associated with decreased survival.

CONCLUSIONS

Atrial arrhythmias are significantly prevalent in patients who require LVAD and are associated with increased mortality; however, LVADs induce favorable atrial structural and electrical remodeling.

Postoperative Management for Patients With Durable Mechanical Circulatory Support Devices

Mechanical circulatory support devices have been approved as bridge to transplantation, as bridge to recovery, or as destination therapy to treat end-stage heart failure. The perioperative challenges for the anesthesiologist and the intensivist caring for these patients include device-related complications, hemodynamic instability, arrhythmias, right ventricular failure, and coagulopathy. Perioperative management in this high-risk population has a significant impact on patient outcomes. This review focuses immediate postoperative intensive care unit management of device-related complications.