The Longitudinal Decline in Peak VO2 with Aging in Healthy Individuals is Associated with a Reduction in Peripheral Oxygen Utilization but not in Cardiac Output.

Aging is associated with a significant decline in exercise fitness assessed by maximal exercise oxygen consumption (VO2-max). The specific VO2-max components driving this decline, namely cardiac output (CO) and arteriovenous oxygen difference (A-V) O2, remain unclear. We examined this issue by analyzing data from 99 community-dwelling participants (baseline age 21-96 years; average follow-up 12.6 years) from the Baltimore Longitudinal Study of Aging, free of clinical cardiovascular disease. VO2-peak, a surrogate of VO2-max, was used to assess aerobic capacity during upright cycle exercise. Peak exercise left ventricular (LV) volumes, heart rate, and cardiac output were estimated using repeated gated cardiac blood pool scans. The Fick equation was used to calculate (A-V) O2-peak from CO-peak and VO2-peak. In unadjusted models, VO2-peak, (A-V) O2-peak, and CO-peakdeclined longitudinally over time at steady rates with advancing age. In multiple linear regression models adjusting for baseline values and peak workload, however, steeper declines in VO2-peak and (A-V) O2 peak were observed with advanced entry age but not in CO-peak. The association between the declines in VO2-peak and (A-V) O2-peakwas stronger among those >=50 years compared to their younger counterparts but the difference between the two age groups did not reach statistical significance. These findings suggest that age-associated impairment of peripheral oxygen utilization during maximal exercise poses a stronger limitation on peak VO2 than that of CO. Future studies examining interventions targeting the structure and function of peripheral muscles and their vasculature to mitigate age-associated declines in (A-V) O2 are warranted.

Variation in Hemodynamic Assessment and Interpretation: A Call to Standardize the Right Heart Catheterization.

BACKGROUND: Invasive hemodynamic measurement via right heart catheterization has shown divergent data in its role in the treatment of patients with heart failure (HF) and cardiogenic shock. We hypothesized that variation in data acquisition technique and interpretation might contribute to these observations. We sought to assess differences in hemodynamic acquisition and interpretation by operator subspecialty as well as level of experience. METHODS AND RESULTS: Individual-level responses to how physicians both collect and interpret hemodynamic data at the time of right heart catheterization was solicited via a survey distributed to international professional societies in HF and interventional cardiology. Data were stratified both by operator subspecialty (HF specialists or interventional cardiologists [IC]) and operator experience (early career [≤10 years from training] or late career [>10 years from training]) to determine variations in clinical practice. For the sensitivity analysis, we also look at differences in each subgroup. A total of 261 responses were received. There were 141 clinicians (52%) who self-identified as HF specialists, 99 (38%) identified as IC, and 20 (8%) identified as other. There were 142 early career providers (54%) and late career providers (119 [46%]). When recording hemodynamic values, there was considerable variation in practice patterns, regardless of subspecialty or level of experience for the majority of the intracardiac variables. There was no agreement or mild agreement among HF and IC as to when to record right atrial pressures or pulmonary capillary wedge pressures. HF cardiologists were more likely to routinely measure both Fick and thermodilution cardiac output compared with IC (51% vs 29%, P < .001), something mirrored in early career vs later career cardiologists. CONCLUSIONS: Significant variation exists between the acquisition and interpretation of right heart catheterization measurements between HF and IC, as well as those early and late in their careers. With the growth of the heart team approach to management of patients in cardiogenic shock, standardization of both assessment and management practices is needed.

Review of Pathophysiology of Cardiogenic Shock and Escalation of Mechanical Circulatory Support Devices.

PURPOSE OF REVIEW: Cardiogenic shock (CS) is a complex clinical entity that continues to carry a high risk of mortality. The landscape of CS management has changed with the advent of several temporary mechanical circulatory support (MCS) devices designed to provide hemodynamic support. It remains challenging to understand the role of different temporary MCS devices in patients with CS, as many of these patients are critically ill, requiring complex care with multiple MCS device options. Each temporary MCS device can provide different types and levels of hemodynamic support. It is important to understand the risk/benefit profile of each one of them for appropriate device selection in patients with CS. RECENT FINDINGS: MCS may be beneficial in CS patients through augmentation of cardiac output with subsequent improvement of systemic perfusion. Selecting the optimal MCS device depends on several variables including the underlying etiology of CS, clinical strategy of MCS use (bridge to recovery, bridge to transplant or durable MCS, or abridge to decision), amount of hemodynamic support needed, associated respiratory failure, and institutional preference. Furthermore, it is even more challenging to determine the appropriate time to escalate from one MCS device to another or combine different MCS devices. In this review, we discuss the current available data published in the literature on the management of CS and propose a standardized approach for escalation of MCS devices in patients with CS. Shock teams can play an important role to help in hemodynamic-guided management and algorithm-based step-by-step approach in early initiation and escalation of temporary MCS devices at different stages of CS. It is important to define the etiology of CS, and stage of shock and recognize univentricular vs biventricular shock for appropriate device selection and escalation of therapy.

Cell-Free DNA to Detect Heart Allograft Acute Rejection.

BACKGROUND: After heart transplantation, endomyocardial biopsy (EMBx) is used to monitor for acute rejection (AR). Unfortunately, EMBx is invasive, and its conventional histological interpretation has limitations. This is a validation study to assess the performance of a sensitive blood biomarker-percent donor-derived cell-free DNA (%ddcfDNA)-for detection of AR in cardiac transplant recipients. METHODS: This multicenter, prospective cohort study recruited heart transplant subjects and collected plasma samples contemporaneously with EMBx for %ddcfDNA measurement by shotgun sequencing. Histopathology data were collected to define AR, its 2 phenotypes (acute cellular rejection [ACR] and antibody-mediated rejection [AMR]), and controls without rejection. The primary analysis was to compare %ddcfDNA levels (median and interquartile range [IQR]) for AR, AMR, and ACR with controls and to determine %ddcfDNA test characteristics using receiver-operator characteristics analysis. RESULTS: The study included 171 subjects with median posttransplant follow-up of 17.7 months (IQR, 12.1-23.6), with 1392 EMBx, and 1834 %ddcfDNA measures available for analysis. Median %ddcfDNA levels decayed after surgery to 0.13% (IQR, 0.03%-0.21%) by 28 days. Also, %ddcfDNA increased again with AR compared with control values (0.38% [IQR, 0.31-0.83%], versus 0.03% [IQR, 0.01-0.14%]; P<0.001). The rise was detected 0.5 and 3.2 months before histopathologic diagnosis of ACR and AMR. The area under the receiver operator characteristic curve for AR was 0.92. A 0.25%ddcfDNA threshold had a negative predictive value for AR of 99% and would have safely eliminated 81% of EMBx. In addition, %ddcfDNA showed distinctive characteristics comparing AMR with ACR, including 5-fold higher levels (AMR ≥2, 1.68% [IQR, 0.49-2.79%] versus ACR grade ≥2R, 0.34% [IQR, 0.28-0.72%]), higher area under the receiver operator characteristic curve (0.95 versus 0.85), higher guanosine-cytosine content, and higher percentage of short ddcfDNA fragments. CONCLUSIONS: We found that %ddcfDNA detected AR with a high area under the receiver operator characteristic curve and negative predictive value. Monitoring with ddcfDNA demonstrated excellent performance characteristics for both ACR and AMR and led to earlier detection than the EMBx-based monitoring. This study supports the use of %ddcfDNA to monitor for AR in patients with heart transplant and paves the way for a clinical utility study. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070.

Characteristics and Outcomes of Patients with Inflammatory Cardiomyopathies Receiving Mechanical Circulatory Support: An STS-INTERMACS Registry Analysis.

BACKGROUND: Durable mechanical circulatory support (MCS) therapy improves survival in patients with advanced heart failure. Knowledge regarding the outcomes experienced by patients with inflammatory cardiomyopathy (CM) who receive durable MCS therapy is limited. METHODS AND RESULTS: We compared patients with inflammatory CM with patients with idiopathic dilated CM enrolled in the STS-INTERMACS registry. Among 19,012 patients, 329 (1.7%) had inflammatory CM and 5978 had idiopathic dilated CM (31.4%). The patients with inflammatory CM were younger, more likely to be White, and women. These patients experienced more preoperative arrhythmias and higher use of temporary MCS. Patients with inflammatory CM had a higher rate of early adverse events (<3 months after device implant), including bleeding, arrhythmias, non-device-related infections, neurologic dysfunction, and respiratory failure. The rate of late adverse events (≥3 months) was similar in the 2 groups. Patients with inflammatory CM had a similar 1-year (80% vs 84%) and 2-year (72% vs 76%, P = .15) survival. Myocardial recovery resulting in device explant was more common among patients with inflammatory CM (5.5% vs 2.3%, P < .001). CONCLUSIONS: Patients with inflammatory CM who received durable MCS appear to have a similar survival compared with patients with idiopathic dilated CM despite a higher early adverse event burden. Our findings support the use of durable MCS in an inflammatory CM population.

Beta-blockers and Ambulatory Inotropic Therapy.

BACKGROUND: Continuous infusion of ambulatory inotropic therapy (AIT) is increasingly used in patients with end-stage heart failure (HF). There is a paucity of data concerning the concomitant use of beta-blockers (BB) in these patients. METHODS: We retrospectively reviewed all patients discharged from our institution on AIT. The cohort was stratified into 2 groups based on BB use. The 2 groups were compared for differences in hospitalizations due to HF, ventricular arrhythmias and ICD therapies (shock or antitachycardia pacing). RESULTS: Between 2010 and 2017, 349 patients were discharged on AIT (95% on milrinone); 74% were males with a mean age of 61 ± 14 years. BB were used in 195 (56%) patients, whereas 154 (44%) did not receive these medications. Patients in the BB group had longer duration of AIT support compared to those in the non-BB group (141 [1-2114] vs 68 [1-690] days). After adjusting for differences in baseline characteristics and indication for AIT, patients in the BB group had significantly lower rates of hospitalizations due to HF (hazard ratio [HR] 0.61 (0.43-0.86); P = 0.005), ventricular arrhythmias (HR 0.34 [0.15-0.74]; P = 0.007) and ICD therapies (HR 0.24 [0.07-0.79]; P = 0.02). CONCLUSION: In patients with end-stage HF on AIT, the use of BB with inotropes was associated with fewer hospitalizations due to HF and fewer ventricular arrhythmias.

Outcomes in patients with smaller body surface area after HeartMate 3 left ventricular assist device implantation.

BACKGROUND: Due to anatomic and physiologic concerns, prior generations of the left ventricular assist devices (LVAD) have frequently been denied to patients with small body size. However, outcomes in patients with small body surface area (BSA) following HeartMate 3 (HM3) LVAD implantation remain relatively unknown. METHODS: A cohort of 220 patients implanted at a single center was divided into two groups: BSA ≤1.8 m2 (small BSA, n = 37) and BSA >1.8 m2 (large BSA, n = 183). We investigated baseline characteristics and clinical outcomes including survival and incidence of adverse events. RESULTS: Small BSA patients were older (60 vs. 57 years), more likely female (60% vs. 20%), had a lower body mass index (24 vs. 32 kg/m2 ), lower incidence of diabetes (32% vs. 51%), history of stroke (5% vs. 19%), and left ventricular thrombus (0% vs. 11%). They had smaller left ventricular end diastolic diameter (64.8 vs. 69.3 mm). Pump speed and pump flows at discharge were lower in the small BSA group. Survival at 1 year and 2 years was 86% versus 87% and 86% versus 79% for small versus large BSA groups (p = 0.408), respectively. The rates of adverse events were similar between groups and there were no cases of confirmed pump thrombosis. The incidence of readmissions for low flow alarms was higher in the small BSA group (0.55 vs. 0.24 EPPY). CONCLUSIONS: These findings demonstrate comparable outcomes in patients with small body size and suggest that this parameter should not be an exclusion criterion on patients who are otherwise candidates for HM3 LVAD implantation.

Chronic Intravenous Inotropic Support as Palliative Therapy and Bridge Therapy for Patients With Advanced Heart Failure: A Single-Center Experience.

BACKGROUND: Many patients with American College of Cardiology/American Heart Association Stage D (advanced) heart failure are discharged home on chronic intravenous inotropic support (CIIS) as bridge to surgical therapy or as palliative therapy. This study analyzed the clinical trajectory of patients with advanced heart failure who were on home CIIS. METHODS: We conducted a single-institution, retrospective cohort study of patients on CIIS between 2010 and 2016 (n = 373), stratified by indication for initiation of inotropic support. Study outcomes were time from initiation of CIIS to cessation of therapy, time to death for patients who did not receive surgical therapy and rates of involvement with palliative care. RESULTS: Overall, patients received CIIS therapy for an average of 5.9 months (standard deviation [SD] 7.3). Patients on CIIS as palliative therapy died in an average of 6.2 months (SD 6.6) from the time of initiation of CIIS, and those on CIIS as bridge therapy who did not ultimately receive surgical therapy died after an average of 8.6 months (SD 9.3). Patients who received CIIS as bridge therapy were significantly less likely to receive palliative-care consultation than those on inotropes as palliative therapy, whether or not they underwent surgery. CONCLUSIONS: In this large cohort of patients with advanced HF, patients who on CIIS as palliative therapy survived for 6.2 months, on average, with wide variation among patients. Patients who were on CIIS as bridge therapy but did not ultimately receive surgical therapy received less palliative care despite the high mortality rate in this subgroup.

VE/VCO2 slope predicts RV dysfunction and mortality after left ventricular assist device: a fresh look at cardiopulmonary stress testing for prognostication.

Preoperative cardiopulmonary exercise testing (CPET) is well validated for prognostication before advanced surgical heart failure therapies, but its role in prognostication after LVAD surgery has never been studied. VE/VCO2 slope is an important component of CPET which has direct pathophysiologic links to right ventricular (RV) performance. We hypothesized that VE/VCO2 slope would prognosticate RV dysfunction after LVAD. All CPET studies from a single institution were collected between September 2009 and February 2019. Patients who ultimately underwent LVAD implantation were selectively analyzed. Peak VO2 and VE/VCO2 slope were measured for all patients. We evaluated their association with hemodynamic, echocardiographic and clinical markers of RV dysfunction as well mortality. Patients were stratified into those with a ventilatory class of III or greater. (VE/VCO2 slope of ≥ 36, n = 43) and those with a VE/VCO2 slope < 36 (n = 27). We compared the mortality between the 2 groups, as well as the hemodynamic, echocardiographic and clinical markers of RV dysfunction. 570 patients underwent CPET testing. 145 patients were ultimately referred to the advanced heart failure program and 70 patients later received LVAD implantation. Patients with VE/VCO2 slope of ≥ 36 had higher mortality (30.2% vs. 7.4%, p = 0.02) than patients with VE/VCO2 slope < 36 (n = 27). They also had a higher incidence of clinically important RVF (Acute severe 9.3% vs. 0%, Severe 32.6% vs 25.9%, p = 0.03). Patients with a VE/VCO2 slope ≥ 36 had a higher CVP than those with a lower VE/VCO2 slope (11.2 ± 6.1 vs. 6.0 ± 4.8 mmHg, p = 0.007), and were more likely to have a RA/PCWP ≥ 0.63 (65% vs. 19%, p = 0.008) and a PAPI ≤ 2 (57% vs. 13%, p = 0.008). In contrast, peak VO2 < 12 ml/kg/min was not associated with postoperative RV dysfunction or mortality. Elevated preoperative VE/VCO2 slope is a predictor of postoperative mortality, and is associated with postoperative clinical and hemodynamic markers of impaired RV performance.

Intrapericardial Left Ventricular Assist Device for Advanced Heart Failure.

BACKGROUND: Mechanical circulatory support with a left ventricular assist device (LVAD) is an established treatment for patients with advanced heart failure. We compared a newer LVAD design (a small intrapericardial centrifugal-flow device) against existing technology (a commercially available axial-flow device) in patients with advanced heart failure who were ineligible for heart transplantation. METHODS: We conducted a multicenter randomized trial involving 446 patients who were assigned, in a 2:1 ratio, to the study (centrifugal-flow) device or the control (axial-flow) device. Adults who met contemporary criteria for LVAD implantation for permanent use were eligible to participate in the trial. The primary end point was survival at 2 years free from disabling stroke or device removal for malfunction or failure. The trial was powered to show noninferiority with a margin of 15 percentage points. RESULTS: The intention-to treat-population included 297 participants assigned to the study device and 148 participants assigned to the control device. The primary end point was achieved in 164 patients in the study group and 85 patients in the control group. The analysis of the primary end point showed noninferiority of the study device relative to the control device (estimated success rates, 55.4% and 59.1%, respectively, calculated by the Weibull model; absolute difference, 3.7 percentage points; 95% upper confidence limit, 12.56 percentage points; P=0.01 for noninferiority). More patients in the control group than in the study group had device malfunction or device failure requiring replacement (16.2% vs. 8.8%), and more patients in the study group had strokes (29.7% vs. 12.1%). Quality of life and functional capacity improved to a similar degree in the two groups. CONCLUSIONS: In this trial involving patients with advanced heart failure who were ineligible for heart transplantation, a small, intrapericardial, centrifugal-flow LVAD was found to be noninferior to an axial-flow LVAD with respect to survival free from disabling stroke or device removal for malfunction or failure. (Funded by HeartWare; ENDURANCE ClinicalTrials.gov number, NCT01166347 .).

Outcomes of Severely Obese Patients Supported by a Centrifugal-Flow Left Ventricular Assist Device.

BACKGROUND: Ventricular assist devices provide improved outcomes for patients with advanced heart failure, but their benefit in the severely obese is not well documented. METHODS: Patients enrolled in the HeartWare ADVANCE trial (n=382) were divided into 2 body mass index (BMI) groups. Patients with severe obesity (>35 kg/m2) were compared with a control group with BMI ≤35 kg/m2. The association of BMI with survival was tested using Kaplan-Meier analysis and major adverse events were compared. RESULTS: At implantation, 48 (13%) of patients were severely obese. There was no difference in survival through 2 years of support between severely obese patients and the control group. Severely obese patients were at higher risk of driveline infection (P = .01) and acute renal dysfunction (P = .002). Both groups experienced similar improvements in quality of life. Functional capacity improved in both severely obese and control patients, although severely obese patients had smaller improvements than controls in their 6-minute walk scores. CONCLUSIONS: Despite an increased risk of adverse events, severe obesity was not associated with reduced survival or quality of life. A better understanding of the risks and benefits of left ventricular assist device therapy in obese patients will help in the shared decision-making of the patient selection process.

Sex-Associated Differences in Cardiac Reverse Remodeling in Patients Supported by Contemporary Left Ventricular Assist Devices.

BACKGROUND: Women differ from men in their left ventricular (LV) structure, function and remodeling with age and diseases. The LV assist device (LVAD) unloads the LV and reversely remodels the heart. We sought to define the effects of sex on longitudinal reverse remodeling after LVAD implantation. METHODS AND RESULTS: Cardiac structure and function were assessed by serial echocardiograms. Mixed effect regression models were constructed to assess the independent contribution of sex to longitudinal changes in cardiac structure and function. A total of 355 consecutive patients with advanced heart failure received continuous flow LVADs between 2006 and 2016. The average age was 56 ± 13 years, 73% were men, and 67% were black. Early (within 3 months) after LVAD implantation, women had a greater reduction in LV dimensions and a greater increase in LV ejection fraction compared with men. These differences were independent of age, body surface area, device type, or ischemic etiology of heart failure. At long-term follow-up, LV dimensions increased slightly over time in women compared with men, but overall, earlier changes were maintained. CONCLUSION: Women had significantly more favorable longitudinal changes in cardiac structure and function in response to LV unloading compared with men. Understanding the cause of sex difference in reverse remodeling after LVAD may help to devise novel therapeutic strategies for women with advanced heart failure.

Hospital readmission in heart failure, a novel analysis of a longstanding problem.

Acute decompensated heart failure is a significant source of morbidity and mortality in the USA. It is the most common reason for admission in the Medicare population and the greatest cause of hospital readmission in both medical and surgical patients. As many of these readmissions are considered preventable, providers and hospital systems are seeking novel strategies to reduce rehospitalization. Several specific interventions have been shown to decrease readmission for heart failure. However, these are typically narrow in scope, focusing on one aspect of patient care and providing a one-size-fits-all approach. We review the data and propose integrating some of these interventions into a comprehensive patient-centered model that is organized into six categories: quality of medical management, early reassessment, health literacy, neuropsychological status, financial means and functional status. By screening for deficiencies in each of these categories, providers and hospital systems can use resources more efficiently to make targeted interventions to improve health outcomes and mitigate readmissions.

Disease-State Understanding and Experience of Patients Receiving Continuous Intravenous Inotropic Support as Palliative Therapy: A Multicenter Survey.

Background: The use of continuous intravenous inotropic support (CIIS) as palliative therapy in patients with advanced heart failure (HF) has increased over the past decade. CIIS improves New York Heart Association (NYHA) functional class but does not impact survival. Objective: The objective of this study was to examine patients' understanding of the therapeutic intent of CIIS, prognostic awareness, and quality of life with CIIS. Design: We conducted a prospective, cross-sectional, multicenter study of patients with advanced HF receiving CIIS as palliative therapy between 2020 and 2022. Settings/Subjects: An investigator-developed survey instrument was administered to outpatients on CIIS in the United States via telephone. Measurements: Survey data were analyzed using descriptive and inferential statistics. Results: Forty-eight patients, 63% male, 81% African American/Black, with a mean age of 68.9 (standard deviation 12.3) years, participated in this study. The majority of patients responded that they expected CIIS to make them feel better (79%) and increase longevity (75%), but few expected that CIIS would cure their HF (19%). Patients described their overall quality of life on CIIS as not better/worse (19%), somewhat better (46%), and significantly better (35%) and reported high treatment satisfaction (87% were at least somewhat satisfied). Conclusions: In this study, patients report improved quality of life with CIIS as palliative therapy. Patients on CIIS as palliative therapy expected increased survival on CIIS, which is incongruent with current evidence. Further studies on how we can improve care processes so that patients have accurate prognostic and disease-state awareness, and receive goal concordant care, are warranted.

PREDICT HF: Risk stratification in advanced heart failure using novel hemodynamic parameters.

BACKGROUND: Invasive hemodynamics are fundamental in assessing patients with advanced heart failure (HF). Several novel hemodynamic parameters have been studied; however, the relative prognostic potential remains ill-defined. HYPOTHESIS: Advanced hemodynamic parameters provide additional prognostication beyond the standard hemodynamic assessment. METHODS: Patients from the PRognostic Evaluation During Invasive CaTheterization for Heart Failure (PREDICT-HF) registry who underwent right heart catheterization (RHC) were included in the analysis. The primary endpoint was survival to orthotopic heart transplant (OHT) or durable left ventricular assist device (LVAD), or death within 6 months of RHC. RESULTS: Of 846 patients included, 176 (21%) met the primary endpoint. In a multivariate model that included traditional hemodynamic variables, pulmonary capillary wedge pressure (PCWP) (OR: 1.10, 1.04-1.15, p < .001), and cardiac index (CI) (OR: 0.86, 0.81-0.92, p < .001) were shown to be predictive of adverse outcomes. In a separate multivariate model that incorporated advanced hemodynamic parameters, cardiac power output (CPO) (OR: 0.76, 0.71-0.83, p < .001), aortic pulsatility index (API) (OR: 0.94, 0.91-0.96, p < .001), and pulmonary artery pulsatility index (OR: 1.02, 1.00-1.03, p .027) were all significantly associated with the primary outcome. Positively concordant API and CPO afforded the best freedom from the endpoint (94.7%), whilst negatively concordant API and CPO had the worst freedom from the endpoint (61.5%, p < .001). Those with discordant API and CPO had similar freedom from the endpoint. CONCLUSION: The advanced hemodynamic parameters API and CPO are independently associated with death or the need for OHT or LVAD within 6 months. Further prospective studies are needed to validate these parameters and elucidate their role in patients with advanced HF.

Benefits and Harms of Continuous Intravenous Inotropic Support as Palliative Therapy: A Single-Institution, Retrospective Analysis.

Use of continuous intravenous inotropic support (CIIS) strictly as palliative therapy for patients with ACC/AHA Stage D (end-stage) Heart Failure (HF) has increased significantly. The harms of CIIS therapy may detract from its benefits. To describe benefits (improvement in NYHA functional class) and harms (infection, hospitalization, days-spent-in-hospital) of CIIS as palliative therapy. Methods: Retrospective analysis of patients with end-stage HF initiated on CIIS as palliative therapy at an urban, academic center in the United States between 2014-2016. Clinical outcomes were extracted, and data were analyzed using descriptive statistics. Seventy-five patients, 72% male, 69% African American/Black, with a mean age 64.5 years (SD = 14.5) met study criteria. Mean duration of CIIS was 6.5 months (SD = 7.7). Most patients (69.3%) experienced improvement in NYHA functional class from class IV to class III. Sixty-seven patients (89.3%) were hospitalized during their time on CIIS, with a mean of 2.7 hospitalizations per patient (SD = 3.3). One-third of patients (n = 25) required at least one intensive care unit (ICU) admission while on CIIS therapy. Eleven patients (14.7%) experienced catheter-related blood stream infection. Patients spent an average of 20.6% (SD = 22.8), approximately 40 days, of their time on CIIS admitted to the study institution. Patients on CIIS as palliative therapy report improvement in functional class, survive 6.5 months following initiation, but spend a significant number of days in the hospital. Prospective studies quantifying the symptomatic benefit and the direct and indirect harms of CIIS as palliative therapy are warranted.

Racial Differences in Donor-Derived Cell-Free DNA and Mitochondrial DNA After Heart Transplantation, on Behalf of the GRAfT Investigators.

BACKGROUND: Black heart transplant patients are at higher risk of acute rejection (AR) and death than White patients. We hypothesized that this risk may be associated with higher levels of donor-derived cell-free DNA (dd-cfDNA) and cell-free mitochondrial DNA. METHODS: The Genomic Research Alliance for Transplantation is a multicenter, prospective, longitudinal cohort study. Sequencing was used to quantitate dd-cfDNA and polymerase chain reaction to quantitate cell-free mitochondrial DNA in plasma. AR was defined as ≥2R cellular rejection or ≥1 antibody-mediated rejection. The primary composite outcome was AR, graft dysfunction (left ventricular ejection fraction <50% and decrease by ≥10%), or death. RESULTS: We included 148 patients (65 Black patients and 83 White patients), median age was 56 years and 30% female sex. The incidence of AR was higher in Black patients compared with White patients (43% versus 19%; P=0.002). Antibody-mediated rejection occurred predominantly in Black patients with a prevalence of 20% versus 2% (P<0.001). After transplant, Black patients had higher levels of dd-cfDNA, 0.09% (interquartile range, 0.001-0.30) compared with White patients, 0.05% (interquartile range, 0.001-0.23; P=0.003). Beyond 6 months, Black patients showed a persistent rise in dd-cfDNA with higher levels compared with White patients. Cell-free mitochondrial DNA was higher in Black patients (185 788 copies/mL; interquartile range, 101 252-422 133) compared with White patients (133 841 copies/mL; interquartile range, 75 346-337 990; P<0.001). The primary composite outcome occurred in 43% and 55% of Black patients at 1 and 2 years, compared with 23% and 27% in White patients, P<0.001. In a multivariable model, Black patient race (hazard ratio, 2.61 [95% CI, 1.35-5.04]; P=0.004) and %dd-cfDNA (hazard ratio, 1.15 [95% CI, 1.03-1.28]; P=0.010) were associated with the primary composite outcome. CONCLUSIONS: Elevated dd-cfDNA and cell-free mitochondrial DNA after heart transplant may mechanistically be implicated in the higher incidence of AR and worse clinical outcomes in Black transplant recipients. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02423070.

EPC mobilization after erythropoietin treatment in acute ST-elevation myocardial infarction: the REVEAL EPC substudy.

Erythropoietin (EPO) was hypothesized to mitigate reperfusion injury, in part via mobilization of endothelial progenitor cells (EPCs). The REVEAL trial found no reduction in infarct size with a single dose of EPO (60,000 U) in patients with ST-segment elevation myocardial infarction. In a substudy, we aimed to determine the feasibility of cryopreserving and centrally analyzing EPC levels to assess the relationship between EPC numbers, EPO administration, and infarct size. As a prespecified substudy, mononuclear cells were locally cryopreserved before as well as 24 and 48-72 h after primary percutaneous coronary intervention. EPC samples were collected in 163 of 222 enrolled patients. At least one sample was obtained from 125 patients, and all three time points were available in 83 patients. There were no significant differences in the absolute EPC numbers over time or between EPO- and placebo-treated patients; however, there was a trend toward a greater increase in EPC levels from 24 to 48-72 h postintervention in patients receiving ≥30,000 U of EPO (P = 0.099 for CD133(+) cells, 0.049 for CD34(+) cells, 0.099 for ALDH(br) cells). EPC numbers at baseline were inversely related to infarct size (P = 0.03 for CD133(+) cells, 0.006 for CD34(+) cells). Local whole cell cryopreservation and central EPC analysis in the context of a multicenter randomized trial is feasible but challenging. High-dose (≥30,000 U) EPO may mobilize EPCs at 48-72 h, and baseline EPC levels may be inversely associated with infarct size.

Genome-wide association analysis identifies multiple loci related to resting heart rate.

Higher resting heart rate is associated with increased cardiovascular disease and mortality risk. Though heritable factors play a substantial role in population variation, little is known about specific genetic determinants. This knowledge can impact clinical care by identifying novel factors that influence pathologic heart rate states, modulate heart rate through cardiac structure and function or by improving our understanding of the physiology of heart rate regulation. To identify common genetic variants associated with heart rate, we performed a meta-analysis of 15 genome-wide association studies (GWAS), including 38,991 subjects of European ancestry, estimating the association between age-, sex- and body mass-adjusted RR interval (inverse heart rate) and approximately 2.5 million markers. Results with P < 5 × 10(-8) were considered genome-wide significant. We constructed regression models with multiple markers to assess whether results at less stringent thresholds were likely to be truly associated with RR interval. We identified six novel associations with resting heart rate at six loci: 6q22 near GJA1; 14q12 near MYH7; 12p12 near SOX5, c12orf67, BCAT1, LRMP and CASC1; 6q22 near SLC35F1, PLN and c6orf204; 7q22 near SLC12A9 and UfSp1; and 11q12 near FADS1. Associations at 6q22 400 kb away from GJA1, at 14q12 MYH6 and at 1q32 near CD34 identified in previously published GWAS were confirmed. In aggregate, these variants explain approximately 0.7% of RR interval variance. A multivariant regression model including 20 variants with P < 10(-5) increased the explained variance to 1.6%, suggesting that some loci falling short of genome-wide significance are likely truly associated. Future research is warranted to elucidate underlying mechanisms that may impact clinical care.