Left-Ventricular Unloading With Impella During Refractory Cardiac Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation: A Systematic Review and Meta-Analysis.

OBJECTIVES: Extracorporeal cardiopulmonary resuscitation (ECPR) is the implementation of venoarterial extracorporeal membrane oxygenation (VA-ECMO) during refractory cardiac arrest. The role of left-ventricular (LV) unloading with Impella in addition to VA-ECMO ("ECMELLA") remains unclear during ECPR. This is the first systematic review and meta-analysis to characterize patients with ECPR receiving LV unloading and to compare in-hospital mortality between ECMELLA and VA-ECMO during ECPR. DATA SOURCES: Medline, Cochrane Central Register of Controlled Trials, Embase, and abstract websites of the three largest cardiology societies (American Heart Association, American College of Cardiology, and European Society of Cardiology). STUDY SELECTION: Observational studies with adult patients with refractory cardiac arrest receiving ECPR with ECMELLA or VA-ECMO until July 2023 according to the Preferred Reported Items for Systematic Reviews and Meta-Analysis checklist. DATA EXTRACTION: Patient and treatment characteristics and in-hospital mortality from 13 study records at 32 hospitals with a total of 1014 ECPR patients. Odds ratios (ORs) and 95% CI were computed with the Mantel-Haenszel test using a random-effects model. DATA SYNTHESIS: Seven hundred sixty-two patients (75.1%) received VA-ECMO and 252 (24.9%) ECMELLA. Compared with VA-ECMO, the ECMELLA group was comprised of more patients with initial shockable electrocardiogram rhythms (58.6% vs. 49.3%), acute myocardial infarctions (79.7% vs. 51.5%), and percutaneous coronary interventions (79.0% vs. 47.5%). VA-ECMO alone was more frequently used in pulmonary embolism (9.5% vs. 0.7%). Age, rate of out-of-hospital cardiac arrest, and low-flow times were similar between both groups. ECMELLA support was associated with reduced odds of mortality (OR, 0.53 [95% CI, 0.30-0.91]) and higher odds of good neurologic outcome (OR, 2.22 [95% CI, 1.17-4.22]) compared with VA-ECMO support alone. ECMELLA therapy was associated with numerically increased but not significantly higher complication rates. Primary results remained robust in multiple sensitivity analyses. CONCLUSIONS: ECMELLA support was predominantly used in patients with acute myocardial infarction and VA-ECMO for pulmonary embolism. ECMELLA support during ECPR might be associated with improved survival and neurologic outcome despite higher complication rates. However, indications and frequency of ECMELLA support varied strongly between institutions. Further scientific evidence is urgently required to elaborate standardized guidelines for the use of LV unloading during ECPR.

Retrospective comparison of traditional and artificial intelligence-based heart failure phenotyping in a US health system to enable real-world evidence.

OBJECTIVE: Quantitatively evaluate the quality of data underlying real-world evidence (RWE) in heart failure (HF). DESIGN: Retrospective comparison of accuracy in identifying patients with HF and phenotypic information was made using traditional (ie, structured query language applied to structured electronic health record (EHR) data) and advanced (ie, artificial intelligence (AI) applied to unstructured EHR data) RWE approaches. The performance of each approach was measured by the harmonic mean of precision and recall (F1 score) using manual annotation of medical records as a reference standard. SETTING: EHR data from a large academic healthcare system in North America between 2015 and 2019, with an expected catchment of approximately 5 00 000 patients. POPULATION: 4288 encounters for 1155 patients aged 18-85 years, with 472 patients identified as having HF. OUTCOME MEASURES: HF and associated concepts, such as comorbidities, left ventricular ejection fraction, and selected medications. RESULTS: The average F1 scores across 19 HF-specific concepts were 49.0% and 94.1% for the traditional and advanced approaches, respectively (p<0.001 for all concepts with available data). The absolute difference in F1 score between approaches was 45.1% (98.1% relative increase in F1 score using the advanced approach). The advanced approach achieved superior F1 scores for HF presence, phenotype and associated comorbidities. Some phenotypes, such as HF with preserved ejection fraction, revealed dramatic differences in extraction accuracy based on technology applied, with a 4.9% F1 score when using natural language processing (NLP) alone and a 91.0% F1 score when using NLP plus AI-based inference. CONCLUSIONS: A traditional RWE generation approach resulted in low data quality in patients with HF. While an advanced approach demonstrated high accuracy, the results varied dramatically based on extraction techniques. For future studies, advanced approaches and accuracy measurement may be required to ensure data are fit-for-purpose.

Cardiogenic shock related cardiovascular disease mortality trends in US population: Heart failure vs. acute myocardial infarction as contributing causes.

BACKGROUND: Observational and trial data have revealed significant improvement in cardiogenic shock (CS) mortality due to acute myocardial infarction (AMI) after introducing early coronary revascularization. Less is known about CS mortality due to heart failure (HF), which is increasingly recognized as a distinct entity from AMI-CS. METHODS AND RESULTS: In this nationwide observational study, the CDC WONDER database was used to identify national trends in age-adjusted mortality rates (AAMR) due to CS (HF vs. AMI related) per 100,000 people aged 35-84. AAMR from AMI-CS decreased significantly from 1999 to 2009 (AAPC: -6.9% [95%CI -7.7, -6.1]) then stabilized from 2009 to 2020. By contrast, HF-CS associated AAMR rose steadily from 2009 to 2020 (AAPC: 13.3% [95%CI 11.4,15.2]). The mortality rate was almost twice as high in males compared to females in both AMI-CS and HF-CS throughout the study period. HF-CS mortality in the non-Hispanic Black population is increasing more quickly than that of the non-Hispanic White population (AAMR in 2020: 4.40 vs. 1.97 in 100,000). The AMI-CS mortality rate has been consistently higher in rural than urban areas (30% higher in 1999 and 28% higher in 2020). CONCLUSIONS: These trends highlight the fact that HF-CS and AMI-CS represent distinct clinical entities. While mortality associated with AMI-CS has primarily declined over the last two decades, the mortality related to HF-CS has increased significantly, particularly over the last decade, and is increasing rapidly among individuals younger than 65. Accordingly, a dramatic change in the demographics of CS patients in modern intensive care units is expected.

The landscape of cardiogenic shock: epidemiology and current definitions.

PURPOSE OF REVIEW: Despite novel technologies for treating shock patients, cardiogenic shock mortality remains high. Trends of cardiogenic shock associated with acute myocardial infarction (AMI) have previously been described, though little is known about cardiogenic shock resulting from other causes, which has progressively been documented as a distinct entity from AMI-cardiogenic shock. Herein, we review the evolving epidemiology, novel classification schema, and future perspectives of cardiogenic shock. RECENT FINDINGS: While AMI or mechanical complications of AMI are the most common causes, the incidence of etiologies of cardiogenic shock not related to AMI, particularly acute on chronic heart failure, may be increasing, with a growing burden of noncoronary structural heart disease. SUMMARY: Mortality in cardiogenic shock remains high. Overall, these findings highlight the need to address the lack of effective treatments in this field, particularly for cardiogenic shock caused by diseases other than AMI. Novel classification systems may facilitate cardiogenic shock research.

Intra-aortic Balloon Pump for Acute-on-Chronic Heart Failure Complicated by Cardiogenic Shock.

The intra-aortic balloon pump (IABP) is widely implanted as temporary mechanical circulatory support for cardiogenic shock (CS). However, its use is declining following the results of the IABP-SHOCK II trial, which failed to show a clinical benefit of the IABP in acute coronary syndrome (ACS)-related CS. Acute-on-chronic heart failure has become an increasingly recognized, distinct cause of CS (HF-CS). The pathophysiology of HF-CS differs from that of ACS-CS because it typically represents the progression from a state of congestion (with relatively preserved cardiac output) to a low-output state with hypoperfusion. The IABP is a volume-displacement pump that promotes forward flow from a high-capacitance reservoir to low-capacitance vessels, improving peripheral perfusion and decreasing left ventricular afterload in the setting of high filling pressures. The IABP can improve ventricular-vascular coupling and, therefore, myocardial energetics. Additionally, many patients with HF-CS are candidates for cardiac replacement therapies (left ventricular assist device or heart transplantation) and, therefore, may benefit from a bridge strategy that stabilizes the hemodynamics and end-organ function in preparation for more durable therapies. Notably, the new United Network for Organ Sharing donor heart allocation system has recently prioritized patients on IABP support. This review describes the role of IABP in the treatment of HF-CS. It also briefly discusses new strategies for vascular access as well as fully implantable versions for longer duration of support.

Impact of Age on Outcomes in Patients With Cardiogenic Shock.

Background: Advanced age is associated with poor outcomes in cardiovascular emergencies. We sought to determine the association of age, use of support devices and shock severity on mortality in cardiogenic shock (CS). Methods: Characteristics and outcomes in CS patients included in the Cardiogenic Shock Work Group (CSWG) registry from 8 US sites between 2016 and 2019 were retrospectively reviewed. Patients were subdivided by age into quintiles and Society for Cardiovascular Angiography & Interventions (SCAI) shock severity. Results: We reviewed 1,412 CS patients with a mean age of 59.9 ± 14.8 years, including 273 patients > 73 years of age. Older patients had significantly higher comorbidity burden including diabetes, hypertension and coronary artery disease. Veno-arterial extracorporeal membrane oxygenation was used in 332 (23%) patients, Impella in 410 (29%) and intra-aortic balloon pump in 770 (54%) patients. Overall in-hospital survival was 69%, which incrementally decreased with advancing age (p < 0.001). Higher age was associated with higher mortality across all SCAI stages (p = 0.003 for SCAI stage C; p < 0.001 for SCAI stage D; p = 0.005 for SCAI stage E), regardless of etiology (p < 0.001). Conclusion: Increasing age is associated with higher in-hospital mortality in CS across all stages of shock severity. Hence, in addition to other comorbidities, increasing age should be prioritized during patient selection for device support in CS.

Predicting survival in patients with acute decompensated heart failure complicated by cardiogenic shock.

BACKGROUND: Acute decompensated heart failure (ADHF) complicated by cardiogenic shock (CS) has unique pathophysiological background requiring specific patient stratification, management and therapeutic targets. Accordingly, the aim of this study was to derive a simple stratification tool to predict survival in patients with ADHF complicated by CS. METHODS AND RESULTS: Using logistic regression, univariable testing was performed to identify the variables potentially associated with 28-day mortality. We propose a new logistic model (ALC-Shock score) based on three easy parameters (age, serum creatinine and serum lactate at the ICU admission) as a powerful predictor of survival or successful bridge to heart replacement therapy at 28-day follow-up in this specific population. A multivariable analysis (logistic model) was performed to evaluate the association between selected variables and outcome (overall death at 28-day follow up). The score was then validated in a different cohort of 93 ADHF-CS patients and compared to a previous developed score (the Cardshock score).Overall, 28-day mortality was 34%. The ALC-shock score showed better discrimination (Area Under the Curve-AUC- 0.82; 95% CI 0.73-0.91) as compared to the Cardshock score (AUC 0.67; 95% CI 0.55-0.79) (p = 0.009) to predict 28-days overall mortality. In the validation cohort the AUC for the ALC-shock score was 0.66. CONCLUSIONS: A simple score including age, lactates and creatinine on admission could be considered to predict short-term mortality in CS-ADHF patients in order to drive towards a treatment intensification.

Clinical Outcomes Associated With Acute Mechanical Circulatory Support Utilization in Heart Failure Related Cardiogenic Shock.

BACKGROUND: Cardiogenic shock occurring in the setting of advanced heart failure (HF-CS) is increasingly common. However, recent studies have focused almost exclusively on acute myocardial infarction-related CS. We sought to define clinical, hemodynamic, metabolic, and treatment parameters associated with clinical outcomes among patients with HF-CS, using data from the Cardiogenic Shock Working Group registry. METHODS: Patients with HF-CS were identified from the multicenter Cardiogenic Shock Working Group registry and divided into 3 outcome categories assessed at hospital discharge: mortality, heart replacement therapy (HRT: durable ventricular assist device or orthotopic heart transplant), or native heart survival. Clinical characteristics, hemodynamic, laboratory parameters, drug therapies, acute mechanical circulatory support device (AMCS) utilization, and Society of Cardiovascular Angiography and Intervention stages were compared across the 3 outcome cohorts. RESULTS: Of the 712 patients with HF-CS identified, 180 (25.3%) died during their index admission, 277 (38.9%) underwent HRT (durable ventricular assist device or orthotopic heart transplant), and 255 (35.8%) experienced native heart survival without HRT. Patients who died had the highest right atrial pressure and heart rate and the lowest mean arterial pressure of the 3 outcome groups (P<0.01 for all). Biventricular and isolated left ventricular congestion were common among patients who died or underwent HRT, respectively. Lactate, blood urea nitrogen, serum creatinine, and aspartate aminotransferase were highest in patients with HF-CS experiencing in-hospital death. Intraaortic balloon pump was the most commonly used AMCS device in the overall cohort and among patients receiving HRT. Patients receiving >1 AMCS device had the highest in-hospital mortality rate irrespective of the number of vasoactive drugs used. Mortality increased with deteriorating Society of Cardiovascular Angiography and Intervention stages (stage B: 0%, stage C: 10.7%, stage D: 29.4%, stage E: 54.5%, 1-way ANOVA=<0.001). CONCLUSIONS: Patients with HF-CS experiencing in-hospital mortality had a high prevalence of biventricular congestion and markers of end-organ hypoperfusion. Substantial heterogeneity exists with use of AMCS in HF-CS with intraaortic balloon pump being the most common device used and high rates of in-hospital mortality after exposure to >1 AMCS device.

Comparison of the Hemodynamic Response to Intra-Aortic Balloon Counterpulsation in Patients With Cardiogenic Shock Resulting from Acute Myocardial Infarction Versus Acute Decompensated Heart Failure.

The intra-aortic balloon pump (IABP) neither benefits nor harms patients with acute myocardial infarction (AMI) with cardiogenic shock (CS) but may stabilize those with chronic heart failure who decompensate into CS. We sought to compare its hemodynamic effects in these 2 populations. We performed a retrospective analysis of the hemodynamic effects of IABP for AMI or acute decompensated heart failure (ADHF) patients with hemodynamic evidence of CS. The primary outcome was cardiac output (CO) change following insertion. In total, 205 patients were treated for CS resulting from AMI (73; 35.6%) or ADHF (132; 64.4%). At baseline, both cohorts had significant hemodynamic compromise with mean arterial pressure 75.6 ± 12.3 mm Hg, CO 3.02 ± 0.84 L/min, and cardiac power index 0.26 ± 0.06 W/m2; these parameters were nearly identical between groups though ADHF-CS patients had a higher pre-IABP mean pulmonary artery (PA) pressure than AMI-CS patients. After IABP insertion, ADHF-CS patients had moderate CO augmentation whereas AMI-CS experienced almost no improvement (0.58 ± 0.79 L/min vs 0.12 ± 1.00 L/min; p = 0.0009). Intracardiac filling pressures were reduced by similar amounts in both cohorts. Systemic vascular resistance was reduced in patients with ADHF-CS but not in those with AMI-CS. In conclusion, following IABP insertion, ADHF-CS patients experience roughly a 5-fold greater CO augmentation compared with AMI-CS patients. Pre-IABP PA pressure differences and differential systemic vascular resistance reduction may explain these results and shed light on recent evidence supporting IABP use in ADHF-CS and curbing it in AMI-CS.

Hemodynamic Effects of Mechanical Circulatory Support Devices in Ventricular Septal Defect.

BACKGROUND: Ventricular septal defect (VSD) is a lethal complication of acute myocardial infarction (AMI) and is often associated with cardiogenic shock. The optimal form of percutaneous mechanical circulatory support (MCS) for AMI-VSD is unknown. METHODS AND RESULTS: We used a previously validated cardiovascular model to simulate AMI-VSD with parameters adjusted to replicate average hemodynamics reported in the literature, including a pulmonary-to-systemic blood flow ratio of 3.0. We then predicted effects of different types of percutaneous MCS (including intra-aortic balloon pumping, Impella, TandemHeart, and extracorporeal membrane oxygenation) on pressures and flows throughout the cardiovascular system. The simulation replicated all major hemodynamic parameters reported in the literature with AMI-VSD. Inotropes and vasopressors worsened left-to-right shunting, whereas vasodilators decreased shunting at the expense of worsening hypotension. All MCS devices increased forward blood flow and arterial pressure but other effects varied among devices. Impella 5.0 provided the greatest degree of pulmonary capillary wedge pressure reductions and decreased left-to-right shunting. Extracorporeal membrane oxygenation worsened pulmonary capillary wedge pressure and shunting, which could be improved by adding Impella or passive left ventricular vent. Pulmonary-to-systemic blood flow ratio could not be reduced below 2.0, and pulmonary flows remained high with all forms of MCS. CONCLUSIONS: Although no form of percutaneous MCS normalized hemodynamics in AMI-VSD, pulmonary capillary wedge pressure and shunting were worsened by extracorporeal membrane oxygenation and improved by Impella. Accordingly, based on hemodynamics alone, Impella provides the optimal form of support in AMI-VSD. However, other factors, including team experience, device availability, potential for tissue ingestion, and clinical characteristics, need to be considered when choosing a percutaneous MCS device for AMI-VSD.

Preoperative Proteinuria and Reduced Glomerular Filtration Rate Predicts Renal Replacement Therapy in Patients Supported With Continuous-Flow Left Ventricular Assist Devices.

BACKGROUND: Renal failure requiring renal replacement therapy (RRT) has detrimental effects on quality of life and survival of patients with continuous-flow left ventricular assist devices (CF-LVADs). Current guidelines do not offer a decision-making algorithm for CF-LVAD candidates with poor baseline renal function. Objective of this study was to identify risk factors associated with RRT after CF-LVAD implantation. METHODS AND RESULTS: Three hundred and eighty-nine consecutive patients underwent contemporary CF-LVAD implantation at the Columbia University Medical Center between January 2004 and August 2015. Baseline demographics, comorbid conditions, clinical risk scores, and renal function were analyzed in patients with or without RRT after CF-LVAD implantation. Time-dependent receiver-operating characteristic curve analysis was performed to define optimal cutoffs for continuous risk factors. Forty-four patients (11.6%) required RRT during a median follow-up of 9.9 months. Patients requiring RRT had significantly worse renal function, lower hemoglobin, and increased proteinuria at baseline. Low estimated glomerular filtration rate (<40 mL/min/1.73 m2) and proteinuria (urine protein to creatinine ratio ≥0.55 mg/mg) were significant predictors of RRT after CF-LVAD support. Dipstick proteinuria was also a significant predictor of RRT after CF-LVAD implantation. Patients with both low estimated glomerular filtration rate and proteinuria had highest risk of RRT (63.6%) compared with those with either low estimated glomerular filtration rate or proteinuria (18.7%) and those with neither of these risk factors (2.7%) at 1-year follow-up (log-rank P<0.001). CONCLUSIONS: Estimated glomerular filtration rate and proteinuria are predictors RRT after CF-LVAD implantation and should be routinely assessed in CF-LVAD candidates to guide decision making.

Impact of Socioeconomic Status on Patients Supported With a Left Ventricular Assist Device: An Analysis of the UNOS Database (United Network for Organ Sharing).

BACKGROUND: Low socioeconomic status (SES) is a known risk factor for heart failure, mortality among those with heart failure, and poor post heart transplant (HT) outcomes. This study sought to determine whether SES is associated with decreased waitlist survival while on left ventricular assist device (LVADs) support and after HT. METHODS AND RESULTS: A total of 3361 adult patients bridged to primary HT with an LVAD between May 2004 and April 2014 were identified in the UNOS database (United Network for Organ Sharing). SES was measured using the Agency for Healthcare Research and Quality SES index using data from the 2014 American Community Survey. In the study cohort, SES did not have an association with the combined end point of death or delisting on LVAD support (P=0.30). In a cause-specific unadjusted model, those in the top (hazard ratio, 1.55; 95% confidence interval, 1.14-2.11; P=0.005) and second greatest SES quartile (hazard ratio 1.50; 95% confidence interval, 1.10-2.04; P=0.01) had an increased risk of death on device support compared with the lowest SES quartile. Adjusting for clinical risk factors mitigated the increased risk. There was no association between SES and complications. Post-HT survival, both crude and adjusted, was decreased for patients in the lowest quartile of SES index compared with all other SES quartiles. CONCLUSIONS: Freedom from waitlist death or delisting was not affected by SES. Patients with a higher SES had an increased unadjusted risk of waitlist mortality during LVAD support, which was mitigated by adjusting for increased comorbid conditions. Low SES was associated with worse post-HT outcomes. Further study is needed to confirm and understand a differential effect of SES on post-transplant outcomes that was not seen during LVAD support before HT.

LVAD implantation following repair of acute postmyocardial infarction ventricular septal defect.

Ventricular septal defect (VSD) is a life-threatening complication of myocardial infarction (MI). Mortality is highest if VSD repair occurs within seven days following MI. We report a case of post-MI VSD stabilized with peripheral veno-arterial extracorporeal membrane oxygenation (VA-ECMO) followed by patch repair and implantation of a durable left ventricular assist device (LVAD).

Contemporary mechanical circulatory support therapy for postcardiotomy shock.

Significant progress has been made in the use of mechanical circulatory support (MCS), particularly in the clinical success in durable left ventricular assist device. Short-term MCS has also advanced in the form of venoarterial extracorporeal membrane oxygenation, external centrifugal VADs as well as percutaneous VADs. Postcardiotomy shock (PCS) is a rare clinical entity associated with substantial morbidity and mortality. It is characterized by heart failure that either results in an inability to wean from cardiopulmonary bypass or that occurs in the immediate postoperative period, accounting for the most common indication for MCS. The reported in-hospital mortality of the PCS patients remains high, consistently over 50%, despite ongoing refinements of MCS technology. The optimization of selection criteria and the prompt institution of MCS are likely the keys to improving this persistently high mortality rate. Unfortunately, the lack of a clear definition for PCS in the literature limits scientific analyses and comparison of the existing evidence. To establish the treatment strategy and appropriately manage this challenging disease, substantial and fundamental effort by the cardiovascular society is imperative.

Effect of pulmonary vascular resistance before left ventricular assist device implantation on short- and long-term post-transplant survival.

OBJECTIVES: Pulmonary hypertension is often considered a contraindication to orthotopic heart transplantation. Left ventricular assist device support may improve pulmonary hypertension by unloading the left ventricle, making patients eligible for transplantation. We sought to investigate the effect of continuous-flow left ventricular assist device support on pulmonary hypertension and compare post-transplantation outcomes in patients with preexisting pulmonary hypertension. METHODS: Between March 2004 and December 2013, 256 potential orthotopic heart transplantation candidates underwent continuous-flow left ventricular assist device implantation at Columbia University. Preimplantation right heart catheterization data were available for 227 patients. Patients were divided into 2 groups on the basis of preimplantation pulmonary vascular resistance: low (<5 Wood units) (n = 182) and high (≥5 Wood units) (n = 45). Postimplantation and post-transplantation outcomes were compared between the groups. RESULTS: Pulmonary vascular resistance in the high resistance group decreased significantly during left ventricular assist device support (P < .001). Post-transplantation in-hospital mortality was significantly higher in patients with high vascular resistance (P < .05). However, 3-year survival after transplantation was similar between groups (85.0% and 79.0% for low and high vascular resistance, respectively; P = .45). CONCLUSIONS: Continuous-flow left ventricular assist device therapy reduced pulmonary vascular resistance. Subsequent orthotopic heart transplantation in patients with significantly elevated pulmonary vascular resistance resulted in higher in-hospital mortality but similar 3-year survival.

Correlation Between Home INR and Core Laboratory INR in Patients Supported with Continuous-Flow Left Ventricular Assist Devices.

It has been well established that patient self-testing (PST) of international normalized ratio (INR) using home monitoring devices increases the average therapeutic time and patient satisfaction. Long-term anticoagulation therapy with warfarin is used in patients with continuous-flow left ventricular assist device (CF-LVAD) to minimize the occurrence of thromboembolic events; however, PST devices have never been tested in patients with CF-LVADs. The purpose of this study was to determine the reliability of the PST device Alere INRatio 2 in patients supported with CF-LVADs. A correlation study was performed in 50 patients with CF-LVAD who were on stable warfarin therapy for a minimum of 3 weeks. Simultaneous INR values were determined from capillary whole blood samples using the Alere PST device and venous blood samples processed in the core laboratory at Columbia University Medical Center. There was a moderate correlation between the venous and the capillary INR values with a correlation coefficient of 0.83. The median difference between the methods was 0.39, with 44 of 50 patients recording higher INRs with Alere. Results remained unchanged after adjusting for use of amiodarone, abnormal hematocrit and liver enzymes, creatinine, and thyroid-stimulating hormone. Point of care testing with Alere correlates moderately well but consistently overestimates INR when compared with conventional laboratory testing in patients with CF-LVAD.