National Landscape of Hospitalizations in Patients with Left Ventricular Assist Device. Insights from the National Readmission Database 2010-2015.

The number of patients with left ventricular assist devices (LVAD) has increased over the years and it is important to identify the etiologies for hospital admission, as well as the costs, length of stay and in-hospital complications in this patient group. Using the National Readmission Database from 2010 to 2015, we identified patients with a history of LVAD placement using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code V43.21. We aimed to identify the etiologies for hospital admission, patient characteristics, and in-hospital outcomes. We identified a total of 15,996 patients with an LVAD, the mean age was 58 years and 76% were males. The most common cause of hospital readmission after LVAD was heart failure (HF, 13%), followed by gastrointestinal (GI) bleed (11.8%), device complication (11.5%), and ventricular tachycardia/fibrillation (4.2%). The median length of stay was 6 days (3-11 days) and the median hospital costs was $12,723 USD. The in-hospital mortality was 3.9%, blood transfusion was required in 26.8% of patients, 20.5% had acute kidney injury, 2.8% required hemodialysis, and 6.2% of patients underwent heart transplantation. Interestingly, the most common cause of readmission was the same as the diagnosis for the preceding admission. One in every four LVAD patients experiences a readmission within 30 days of a prior admission, most commonly due to HF and GI bleeding. Interventions to reduce HF readmissions, such as speed optimization, may be one means of improving LVAD outcomes and resource utilization.

Heart transplant recipients with confirmed 2019 novel coronavirus infection: The Detroit experience.

A chronic immunosuppressed state as in solid organ transplant recipients is a reported risk factor for the novel 2019 coronavirus infection. Patients with a history of orthotopic heart transplant (OHT) at a tertiary care transplant center in Detroit, Michigan were retrospectively reviewed from March until May 2020. Clinical parameters and outcomes of 5 OHT recipients and one combined heart-lung recipient with confirmed SARS-CoV-2 were obtained. The cohort was predominately African American males with median age of 59 years (interquartile range, 48.25-73.25). All patients were classified as having mild-moderate disease; none required intubation or ICU admission with no deaths. The most common presenting symptoms were fever and shortness of breath 83% (n = 5), followed by cough and chills 67% (n = 4). All admitted patients (n = 5) received hydroxychloroquine and 3 received high-dose steroids. Antimetabolites were held for 2 patients (33.3%). The calcineurin inhibitor trough goal was decreased in only 1 patient; 3 other patients, without change in goal, required calcineurin inhibitor dosage reduction. Two patients requiring readmission presented 7 and 23 days after initial symptoms onset. In conclusion, our experience with OHT patients infected by the SARS-CoV-2 virus did not have an elevated risk of severe infection. Impact of modifying immunosuppression remains unclear.

Pulmonary Function Testing and Outcomes after Left Ventricular Assist Device Implantation.

BACKGROUND: Pulmonary function testing (PFT) is often done during workup prior to left ventricular assist devices (LVAD), but its utility for predicting outcomes and changes in pulmonary function post-LVAD is not well established. We assessed the association of baseline PFT metrics with outcomes after LVAD, and quantified the changes in PFTs post-LVAD. METHODS AND RESULTS: A retrospective study of 178 patients receiving continuous flow LVADs was conducted. A total of 129 subjects had baseline PFT data and 54 of these had repeat tests after LVAD. We collected PFT data (FEV1, FVC, FEV1/FVC ratios, and DLCO) at baseline and post-LVAD, and tested the association with survival, right heart failure, quality of life (Kansas City Cardiomyopathy Questionnaire [KCCQ]) and functional capacity (six-minute walking distance [6MWD]). Proportional hazards and linear regressions determined relationships between baseline PFT data and survival time and functional outcomes, respectively. Paired t-tests compared pre- and post- LVAD PFT variables. There was no association of baseline PFT parameters with survival time post-LVAD (all P > .2), nor the incidence of perioperative RV failure (all P > .15). There were no significant associations of the baseline PFT metrics with the change in KCCQ or 6MWD.  There were statistically significant declines in FEV1, FEV1/FVC ratio, and DLCO after LVAD (P < .05). CONCLUSION: In this single center study, there was no relationship between baseline PFTs and post-LVAD outcomes, and PFT parameters often worsened after LVAD. Further studies are needed to determine whether PFTs are useful in this setting, and what, if any, impact LVAD therapy has on pulmonary function.

Anticoagulation of Percutaneous Ventricular Assist Device Using Argatroban-Based Purge Solution: A Case Series.

Impella devices are percutaneously inserted ventricular assist devices which require a continuous purge solution that contains heparin to prevent pump thrombosis and device failure. We describe 2 patients with heparin-induced thrombocytopenia (HIT) supported with an Impella device utilizing an argatroban-based purge solution. Case 1 involved an 83-year-old female with biventricular failure which resulted in right ventricle Impella support. The purge solution was changed to include argatroban due to concern of device clotting in the setting of HIT. Case 2 involved a 55-year-old male with worsening cardiogenic shock which resulted in left ventricle Impella support. Due to decreased purge flow rates and concerns for clotting, argatroban was added to the purge solution. Both patients' total argatroban regimens were monitored and adjusted by pharmacy, resulting in therapeutic anticoagulation without any major bleeding or thrombotic events. Subsequently, a protocol was designed and implemented. These case reports appear to demonstrate the safe and effective use of argatroban purge solutions for the necessary anticoagulation with an Impella device. Further studies are needed to confirm these results and determine the optimal dosing regimen.

Prognostic value of cardiopulmonary exercise testing in heart failure with preserved ejection fraction. The Henry Ford HospITal CardioPulmonary EXercise Testing (FIT-CPX) project.

BACKGROUND: Although cardiopulmonary exercise (CPX) testing in patients with heart failure and reduced ejection fraction is well established, there are limited data on the value of CPX variables in patients with HF and preserved ejection fraction (HFpEF). We sought to determine the prognostic value of select CPX measures in patients with HFpEF. METHODS: This was a retrospective analysis of patients with HFpEF (ejection fraction ≥ 50%) who performed a CPX test between 1997 and 2010. Selected CPX variables included peak oxygen uptake (VO2), percent predicted maximum oxygen uptake (ppMVO2), minute ventilation to carbon dioxide production slope (VE/VCO2 slope) and exercise oscillatory ventilation (EOV). Separate Cox regression analyses were performed to assess the relationship between each CPX variable and a composite outcome of all-cause mortality or cardiac transplant. RESULTS: We identified 173 HFpEF patients (45% women, 58% non-white, age 54 ± 14 years) with complete CPX data. During a median follow-up of 5.2 years, there were 42 deaths and 5 cardiac transplants. The 1-, 3-, and 5-year cumulative event-free survival was 96%, 90%, and 82%, respectively. Based on the Wald statistic from the Cox regression analyses adjusted for age, sex, and ß-blockade therapy, ppMVO2 was the strongest predictor of the end point (Wald χ(2) = 15.0, hazard ratio per 10%, P < .001), followed by peak VO2 (Wald χ(2) = 11.8, P = .001). VE/VCO2 slope (Wald χ(2)= 0.4, P = .54) and EOV (Wald χ(2) = 0.15, P = .70) had no significant association to the composite outcome. CONCLUSION: These data support the prognostic utility of peak VO2 and ppMVO2 in patients with HFpEF. Additional studies are needed to define optimal cut points to identify low- and high-risk patients.

Heart Rate and V˙O2 Concordance in Continuous-Flow Left Ventricular Assist Devices.

UNLABELLED: The American College of Sports Medicine currently recommends the HR reserve (HRR) method to guide exercise in individuals who have heart failure with reduced ejection fraction. This recommendation is based on the known association between %HRR and percentage of V˙O2 reserve (%V˙O2R) in this population. However, to our knowledge, no studies exist regarding this relation in individuals with a left ventricular assist device (LVAD). PURPOSE: This article aimed to describe the relation between V˙O2 and surrogate markers of exercise intensity among patients with LVAD. METHODS: Patients with continuous-flow LVAD (n = 24, seven females) completed a symptom-limited graded exercise test on a treadmill. HR and V˙O2 were measured continuously and averaged every 20 s. Regression equations were determined using a generalized estimating equation to predict %V˙O2R from %HRR, Borg RPE, and LVAD flow, overall and stratified by presence of pacing. RESULTS: Although the association between %HRR and %V˙O2R was good (R = 0.75), the slope and y-intercept for %HRR versus %V˙O2R was different from the line of identity (P = 0.002). However, when paced subjects were excluded (n = 8) from the analysis, there was no significant difference between the slope and y-intercept (= 0.036 + 0.937 × %HRR; SEE, 2%; P = 0.052). RPE showed a strong association with %V˙O2R (R = 0.84), whereas LVAD flow showed a weak (albeit statistically significant) association (R = 0.05). Both had slopes and y-intercepts that were different from the line of identity (P < 0.05). CONCLUSIONS: In patients with LVAD who are not paced during exercise, the use of %HRR is a good predictor of %V˙O2R. However, for patients in this population who are also paced during exercise, RPE is a suitable surrogate measure of exercise intensity.

Comprehensive analysis of cardiopulmonary exercise testing and mortality in patients with systolic heart failure: the Henry Ford Hospital cardiopulmonary exercise testing (FIT-CPX) project.

BACKGROUND: Many studies have shown a strong association between numerous variables from a cardiopulmonary exercise (CPX) test and prognosis in patients with heart failure with reduced ejection fraction (HFrEF). However, few studies have compared the prognostic value of a majority of these variables simultaneously, so controversy remains regarding optimal interpretation. METHODS AND RESULTS: This was a retrospective analysis of patients with HFrEF (n = 1,201; age = 55 ± 13 y; 33% female) and a CPX test from 1997 to 2010. Thirty variables from a CPX test were considered in separate adjusted Cox regression analyses to describe the strength of the relation of each to a composite end point of all-cause mortality, left ventricular assist device implantation, or heart transplantation. During a median follow-up of 3.8 years, there were 577 (48.0%) events. The majority of variables were highly significant (P < .001). Among these, percentage of predicted maximum V˙O2 (ppMV˙O2; Wald = 203; P < .001; C-index = 0.73) was similar to VE-VCO2 slope (Wald = 201; P < .001; C = 0.72) and peak V˙O2 (Wald = 161; P < .001; C = 0.72). In addition, there was no significant interaction observed for peak respiratory exchange ratio <1 vs ≥1. CONCLUSIONS: Consistent with prior studies, many CPX test variables were strongly associated with prognosis in patients with HFrEF. The choice of which variable to use is up to the clinician. Renewed attention should be given to ppMV˙O2, which appears to be highly predictive of survival in these patients.

Relationship of tricuspid repair at the time of left ventricular assist device implantation and survival.

PURPOSE: Tricuspid regurgitation contributes to right ventricular failure (RVF) and is associated with worse clinical outcomes in patients undergoing left ventricular assist device (LVAD) treatment. However, whether tricuspid valve repair (TVR) at the time of LVAD implantation improves outcomes is not clear. METHODS: We identified all patients undergoing initial implantation of a long-term continuous-flow LVAD at our institution from March 2006 to August 2011. We assessed the impact of TVR on survival and incidence of RVF using Kaplan-Meier curves and proportional hazards regression adjusted for age, gender, baseline tricuspid regurgitation, RV function, MELD score, albumin, and indication (bridge vs. destination). RESULTS: A total of 101 patients were included in the analysis, of which 14 patients underwent TVR concomitant LVAD. All TVR patients had moderate or severe baseline regurgitation. Crude survival was not different between groups. In multivariable models adjusted for confounding factors, TVR showed a significant association with improved survival (HR = 0.1, p = 0.049). Adjusted models showed no difference in RVF. CONCLUSIONS: In this cohort of patients, TVR at the time of LVAD implantation appears associated with better survival. Additional larger studies are needed to verify the effect of TVR at the time of LVAD implantation, and whether it should be utilized more frequently.

Cardiac rehabilitation improves functional capacity and patient-reported health status in patients with continuous-flow left ventricular assist devices: the Rehab-VAD randomized controlled trial.

OBJECTIVES: This study examined the effects of a cardiac rehabilitation (CR) program on functional capacity and health status (HS) in patients with newly implanted left ventricular assist devices (LVADs). BACKGROUND: Reduced functional capacity and HS are independent predictors of mortality in patients with heart failure. CR improves both, and is related to improved outcomes in patients with heart failure; however, there is a paucity of data that describe the effects of CR in patients with LVADs. METHODS: Enrolled subjects (n = 26; 7 women; age 55 ± 13 years; ejection fraction 21 ± 8%) completed a symptom-limited cardiopulmonary exercise test, the Kansas City Cardiomyopathy Questionnaire (KCCQ), a 6-min walk test (6MW), and single-leg isokinetic strength test before 2:1 randomization to CR versus usual care. Subjects in the CR group underwent 18 visits of aerobic exercise at 60% to 80% of heart rate reserve. Within-group changes from baseline to follow-up were analyzed with a paired t-test, whereas an independent t-test was used to determine differences in the change between groups. RESULTS: Within-group improvements were observed in the CR group for peak oxygen uptake (10%), treadmill time (3.1 min), KCCQ score (14.4 points), 6MW distance (52.3 m), and leg strength (17%). Significant differences among groups were observed for KCCQ, leg strength, and total treadmill time. CONCLUSIONS: Indicators of functional capacity and HS are improved in patients with continuous-flow LVADs who attend CR. Future trials should examine the mechanisms responsible for these improvements, and if such improvements translate into improved clinical outcomes. (Cardiac Rehabilitation in Patients With Continuous Flow Left Ventricular Assist Devices:Rehab VAD Trial [RehabVAD]; NCT01584895).

Tissue 65Zinc translocation in a rat model of chronic aldosteronism.

Zinc, an essential micronutrient, is involved in wound healing. The hypozincemia seen with chronic aldosteronism is associated with enhanced fecal and urinary excretory Zn losses, and its tissue distribution is less certain. This study monitored tissue 65Zn distribution in uninephrectomized rats at weeks 1 and 4 of aldosterone/salt treatment (ALDOST). Plasma and tissue total radionucleotide uptake was determined by calculating its mean radioactivity at 1, 4, 8, 24, and 48 hours after intravenous 65Zn administration and where respective area under the concentration-time curves (AUC) were determined by the linear trapezoidal rule and expressed as a tissue:plasma AUC ratio. Examined tissues included: (1) injured heart and kidney in response to ALDOST and incised skin; (2) noninjured liver, skeletal muscle, and spleen sites of stress-linked Zn uptake; and (3) bone, a major storage and release site when Zn homeostasis is threatened. In comparison with age-matched and gender-matched controls, the following were found with week 1 and 4 ALDOST: (1) reduced plasma 65Zn; (2) an accumulation of 65Zn in heart and kidneys, where a well-known vasculopathy involves intramural vessels, and in incised skin at week 1; (3) an organ-specific increase in tissue 65Zn in liver, in keeping with upregulated metallothionein expression, skeletal muscle, and spleen; and (4) a fall in bone and healed skin Zn at week 4. Thus a wide-ranging disturbance in Zn homeostasis appears during ALDOST to include its translocation from plasma to injured heart, kidneys, and skin and noninjured liver, skeletal muscle, and spleen together with a resorption of stored Zn in bone at week 4. Zinc dyshomeostasis is an integral feature of chronic aldosteronism.

The salt-avid state of congestive heart failure revisited.

Congestive heart failure (CHF), a clinical syndrome, comprises a constellation of signs and symptoms whose origins are rooted in a salt-avid state mediated largely by effector hormones of the renin-angiotensin-aldosterone system (RAAS). Stimuli that normally lead to an activation of this circulating neurohormonal system include reduced dietary sodium, upright posture with or without exercise, and thermal stress. These stimuli remain operative in patients with heart failure; however, here renal perfusion is reduced, leading to excessive RAAS activation. This can contribute to an inability to adequately excrete dietary sodium (salt sensitivity). Active Na+ and water retention (salt avidity) account for an initial expansion of intravascular volume and subsequent rise in extravascular volume. Neurohormonal regulation of Na+ excretion therefore is the pathophysiologic basis for clinical decompensation and the appearance of CHF. By contrast, and despite comparable levels of heart failure, expressed as diastolic or systolic ventricular dysfunction, patients in whom circulating RAAS hormones remain normal are clinically compensated without CHF. Interventions, such as regulated dietary Na+, prolonged bed rest, intermittent periods of semirecumbency (with legs up), water immersion, thermal neutrality, and pharmacologic interference with the generation and activity of RAAS hormones, can be used to attenuate the salt avidity found in patients with CHF.

Cinacalcet and the prevention of secondary hyperparathyroidism in rats with aldosteronism.

BACKGROUND: In rats receiving aldosterone/salt treatment (ALDOST), increased Ca2+ excretion leads to a fall in plasma-ionized Ca2+ and appearance of secondary hyperparathyroidism (SHPT) with parathyroid hormone (PTH)-mediated intracellular Ca2+ overloading inducing oxidative stress in diverse tissues. Parathyroidectomy prevents this scenario. Rats with ALDOST were cotreated with cinacalcet (Cina), a calcimimetic that raises the threshold of the parathyroids' Ca(2+)-sensing receptor. METHODS AND RESULTS: We monitored plasma-ionized [Ca2+]o, PTH, and total Ca2+ in heart and peripheral blood mononuclear cells (PBMC), and evidence of oxidative stress in heart, PBMC, and plasma. Cina-treated rats for 4 weeks were compared with 4 weeks of ALDOST alone and with untreated age-/gender-matched controls. In comparison to controls, ALDOST led to a fall (P < 0.05) in Ca2+ (1.16 +/- 0.01 vs 1.03 +/- 0.01 mmol/L), which was not prevented by Cina (1.01 +/- 0.03 mmol/L); a rise (P < 0.05) in plasma PTH (36 +/- 7 vs 134 +/- 19 pg/mL) that was attenuated by Cina (69 +/- 12 pg/mL); increased (P < 0.05) cardiac [Ca2+] (3.92 +/- 0.25 vs 6.78 +/- 0.35 nEq/mg FFDT) and PBMC [Ca2+]i (29.8 +/- 2.3 vs 50.2 +/- 2.3 nmol/L), each of which was prevented with Cina (3.65 +/- 0.10 nEq/mg FFDT and 32.5 +/- 6.0 nmol/L, respectively); increased cardiac MDA (0.56 +/- 0.03 vs 0.94+/-0.07 nmol/mg protein) and PBMC H2O2 production (63.5 +/- 7.5 vs 154.0 +/- 25.2 mcb) and reduced (P < 0.05) plasma alpha1-AP activity (39.8 +/- 0.6 vs 29.6 +/- 1.8 mM), each prevented by Cina (0.66 +/- 0.04 mmol/mg protein, 58.2 +/- 12.7 mcb and 37.0 +/- 1.2 mM, respectively). CONCLUSIONS: PTH-mediated intracellular Ca2+ overloading accounts for the induction of oxidative stress in diverse tissues in rats with aldosteronism and which can be prevented by Cina.

Developing a simpler measure of diabetes care quality.

The researchers developed a diabetes care quality summary score (DCQSS) that weights blood pressure, tobacco use, glucose information, and lipid information by cost-effectiveness for improving cardiovascular outcomes. They compared the DCQSS to selected Diabetes Quality Improvement Project (DQIP) measures of care in an urban Medicaid healthcare maintenance organization population using a retrospective chart review. The DCQSS assesses cardiovascular risk compared to individual risk-factor control with DQIP measures. The authors believe that the DCQSS provides an easier interpretation of diabetes quality than multiple DQIP measures.