A heart transplant center experience with basiliximab induction strategies: A double edged sword?

BACKGROUND: The use of induction immunosuppression for heart transplantation (HT) is debated given the uncertain benefit and potential risks of infection and malignancy. METHODS: This is a retrospective single-center analysis of 475 consecutive HT recipients from 2003 to 2020 grouped by use of induction with basiliximab group (BG) and the no basiliximab group (NBG). Subgroup analysis by era compared pre-2016 standard-basiliximab (BX) induction and 2016-2020 with selective-BX use as part of a calcineurin-inhibitor-sparing regimen. RESULTS: When adjusted for confounders (sex, age, PRA, eGFR), the BG was less likely to have acute cellular rejection (ACR) (OR.42, p < .001), but had more antibody mediated rejection (AMR) (OR 11.7, p < .001) and more cardiac allograft vasculopathy (CAV) (OR 3.8, p = .04). There was no difference between BG and NBG in the incidence of malignancies or infections. When stratified by era (pre-2016 vs. 2016-2020), ACR remained less common in the BG than the NBG (36% vs. 50%, p = .045) groups, while AMR remained more common (9.7 vs. 0% p = .005). There was no significant difference in conditional survival comparing pre-and post-2016 NBG (HR 2.20 (95% CI.75-6.43); however, both pre-2016 BG and post-2016 BG have significantly higher mortality (HR 2.37 [95% CI 1.02-5.50) and HR 2.69 (95% CI 1.08-6.71), p = .045 and.03, respectively]. CONCLUSION: Basiliximab reduces the incidence of ACR but increases the risk of AMR, CAV, and may be associated with increased mortality. Mechanistic studies are needed to describe a potential T-cell-escape mechanism with enhanced humoral immunity.

The End of Endomyocardial Biopsy?: A Practical Guide for Noninvasive Heart Transplant Rejection Surveillance.

Noninvasive heart transplant rejection surveillance using gene expression profiling (GEP) to monitor immune activation is widely used among heart transplant programs. With the new development of donor-derived cell-free DNA (dd-cfDNA) assays, more programs are transitioning to a predominantly noninvasive rejection surveillance protocol with a reduced frequency of endomyocardial biopsies. As a result, many practical questions arise that potentially delay implementation of these valuable new tools. The purpose of this review is to provide practical guidance for clinicians transitioning toward a less invasive acute rejection monitoring protocol after heart transplantation, and to answer 10 common questions about the GEP and dd-cfDNA assays. Evidence supporting GEP and dd-cfDNA testing is reviewed, as well as guidance on test interpretation and future directions.

Biventricular Pacing Versus Right Ventricular Pacing in Patients Supported With LVAD.

OBJECTIVES: This study sought to evaluate the effects of right ventricular (RV) pacing versus biventricular (BiV) pacing on quality of life, functional status, and arrhythmias in LVAD patients. BACKGROUND: Cardiac resynchronization therapy (CRT) and left ventricular assist devices (LVADs) independently improve outcomes in heart failure patients, but the effects of combining these therapies remains unknown. We present the first prospective randomized study evaluating the effects of RV versus BiV pacing on quality of life, functional status, and arrhythmias in LVAD patients. METHODS: In this prospective randomized crossover study, LVAD patients with prior CRT devices were alternated on RV and BiV pacing for planned 7-14-day periods. Ambulatory step count, 6-minute walk test distance, Kansas City Cardiomyopathy Questionnaire scores, arrhythmia burden, CRT lead function, and echocardiographic data were collected with each pacing mode. RESULTS: Thirty patients were enrolled, with a median age of 65 years, 67% male, and mean duration of LVAD support of 309 days. Compared with BiV pacing, RV-only pacing resulted in 29% higher mean daily step count, 11% higher 6-minute walk test distance, and 7% improved KCCQ-12 score (all p < 0.03). LV end-diastolic volume was significantly lower with RV pacing (220 vs. 250 mL; p = 0.03). Fewer patients had ventricular tachyarrhythmia episodes during RV pacing (p = 0.03). RV lead impedance was lower with RV pacing (p = 0.047), but no significant differences were observed in impedance across other CRT leads. CONCLUSIONS: In the first prospective randomized study comparing variable pacing in LVAD patients, RV pacing was associated with significantly improved functional status, quality of life, fewer ventricular tachyarrhythmias, and stable lead impedance compared with BiV pacing. This study supports turning off LV lead pacing in LVAD patients with CRT.

Comparison of Glidescope Core, C-MAC Miller and conventional Miller laryngoscope for difficult airway management by anesthetists with limited and extensive experience in a simulated Pierre Robin sequence: A randomized crossover manikin study.

BACKGROUND: Video laryngoscopy is an effective tool in the management of difficult pediatric airway. However, evidence to guide the choice of the most appropriate video laryngoscope (VL) for airway management in pediatric patients with Pierre Robin syndrome (PRS) is insufficient. Therefore, the aim of this study was to compare the efficacy of the Glidescope® Core™ with a hyperangulated blade, the C-MAC® with a nonangulated Miller blade (C-MAC® Miller) and a conventional Miller laryngoscope when used by anesthetists with limited and extensive experience in simulated Pierre Robin sequence. METHODS: Forty-three anesthetists with limited experience and forty-three anesthetists with extensive experience participated in our randomized crossover manikin trial. Each performed endotracheal intubation with the Glidescope® Core™ with a hyperangulated blade, the C-MAC® with a Miller blade and the conventional Miller laryngoscope. "Time to intubate" was the primary endpoint. Secondary endpoints were "time to vocal cords", "time to ventilate", overall success rate, number of intubation attempts and optimization maneuvers, Cormack-Lehane score, severity of dental trauma and subjective impressions. RESULTS: Both hyperangulated and nonangulated VLs provided superior intubation conditions. The Glidescope® Core™ enabled the best glottic view, caused the least dental trauma and significantly decreased the "time to vocal cords". However, the failure rate of intubation was 14% with the Glidescope® Core™, 4.7% with the Miller laryngoscope and only 2.3% with the C-MAC® Miller when used by anesthetists with extensive previous experience. In addition, the "time to intubate", the "time to ventilate" and the number of optimization maneuvers were significantly increased using the Glidescope® Core™. In the hands of anesthetists with limited previous experience, the failure rate was 11.6% with the Glidescope® Core™ and 7% with the Miller laryngoscope. Using the C-MAC® Miller, the overall success rate increased to 100%. No differences in the "time to intubate" or "time to ventilate" were observed. CONCLUSIONS: The nonangulated C-MAC® Miller facilitated correct placement of the endotracheal tube and showed the highest overall success rate. Our results therefore suggest that the C-MAC® Miller could be beneficial and may contribute to increased safety in the airway management of infants with PRS when used by anesthetists with limited and extensive experience.

HeartWare Ventricular Assist Device Cannula Position and Hemocompatibility-Related Adverse Events.

BACKGROUND: HeartWare ventricular assist device (HVAD) cannula position is associated with hemodynamics and heart failure readmissions. However, its impact on hemocompatibility-related adverse events (HRAEs) remains uncertain. METHODS: HVAD patients were followed for 1 year after index hospitalization, when cannula coronal angle was quantified from chest x-ray film. Invasive right heart catheterization and transthoracic echocardiography were performed. One-year occurrences of each HRAE were compared between those with and without a cannula coronal angle of greater than 65 degrees. RESULTS: Among 63 HVAD patients (median age 60 years, 63% male), 10 (16%) had a cannula coronal angle greater than 65 degrees. The wide-angle group had elevated intracardiac pressures and lower pulmonary artery pulsatility index (P < .05). They also had reduced right ventricular function by echocardiography. Freedom from HRAEs tended to be lower in the wide-angle group (24% vs 62%; P = .11). The rate of gastrointestinal bleeding was significantly higher in the greater than 65 degrees group (0.90 events/year vs 0.40 events/year; P = .013). The rates of stroke and pump thrombosis were statistically comparable irrespective of cannula angle (P > .05). CONCLUSIONS: HVAD cannula coronal angle was associated with reduced right ventricular function and HRAEs. Prospective studies evaluating surgical techniques to ensure optimal device positioning and its effects on HRAEs are warranted.

Effect of Concomitant Tricuspid Valve Surgery With Left Ventricular Assist Device Implantation.

BACKGROUND: Tricuspid regurgitation (TR) is common in advanced heart failure (HF) patients. However, the effect of concomitant tricuspid valve repair or replacement (tricuspid valve intervention [TVI]) with left ventricular assist device (LVAD) implantation is controversial. The aim of this study was to investigate the longitudinal trend of TR after LVAD implantation and the effect of TVI on the TR trend and clinical outcomes. METHODS: We retrospectively reviewed patients at our institution who underwent LVAD implantation between April 2014 and August 2018. We evaluated the grade of TR by echocardiography before and after LVAD implantation. Moderate or greater TR was defined as significant. RESULTS: Among 199 consecutive patients, 194 had at least 2 echocardiographic TR assessments before and after LVAD implantation. Of these patients, 108 were included in the TVI-positive (TVI+) group and 86 in the TVI-negative (TVI-) group. In the TVI+ group, the prevalence of significant TR decreased from 52% to about 20% in the first 6 months after implantation (P < .01). Overall survival and HF readmission-free survival were comparable between the TVI+ and TVI- patients. In contrast, patients in both groups who had significant postoperative TR during early follow-up had worse 2-year HF readmission-free survival (36% in patients with significant postoperative TR vs 55% in those without significant postoperative TR; P = .028). CONCLUSIONS: Concomitant TVI with LVAD implantation improved TR in most patients but did not have an impact on clinical outcomes. Significant postoperative TR after LVAD implantation, in patients with and without TVI, was associated with worse HF-free outcomes.

Estimation of the Severity of Aortic Insufficiency by HVAD Flow Waveform.

PURPOSE: Aortic insufficiency (AI) significantly affects morbidity and mortality in patients with left ventricular assist devices. Although AI may be commonly assessed by echocardiography, expert techniques are required for accurate quantification of AI severity. DESCRIPTION: In this prospective blinded study, screenshots from the HVAD (Medtronic, Framingham, MA) display and simultaneous echocardiographic measurements were obtained. Each screenshot was digitized and the early diastolic phase slope was calculated, with blinding to the echocardiographic results. The regurgitant fraction of AI was quantified by Doppler echocardiography of the outflow graft. EVALUATION: A total of 30 patients (median, 57 years old; 57% male) were enrolled. A cutoff of -17.6 L/min/s for the early diastolic phase slope had a sensitivity of 0.92 and a specificity of 0.53 to estimate significant AI with a regurgitant fraction of 30% or greater, and it significantly stratified patients into a low regurgitant faction group (0.3%) and a high regurgitant fraction group (33.0%) (P = .009). The early diastolic phase slope had a moderate correlation with the actually measured regurgitant fraction (r = .50). CONCLUSIONS: The early diastolic phase slope of the HVAD flow waveform may be a parameter that can estimate the presence of clinically significant AI.

The forkhead transcription factor Foxo3 negatively regulates natural killer cell function and viral clearance in myocarditis.

Aims: Foxo3 is a transcription factor involved in cell metabolism, survival, and inflammatory disease. However, mechanistic insight in Foxo3 effects is still limited. Here, we investigated the role of Foxo3 on natural killer (NK) cell responses and its effects in viral myocarditis. Methods and results: Effects of Foxo3 on viral load and immune responses were investigated in a model of coxsackie virus B3 myocarditis in wild-type (WT) and Foxo3 deficient mice. Reduced immune cell infiltration, viral titres, and pro-inflammatory cytokines in cardiac tissue were observed in Foxo3-/- mice 7 days post-infection (p.i.). Viral titres were also attenuated in hearts of Foxo3-/- mice at Day 3 while interferon-γ (IFNγ) and NKp46 expression were up-regulated suggesting early viral control by enhanced NK cell activity. CD69 expression of NK cells, frequencies of CD11b+CD27+ effector NK cells and cytotoxicity of Foxo3-/- mice was enhanced compared to WT littermates. Moreover, microRNA-155 expression, essential in NK cell activation, was elevated in Foxo3-/- NK cells while its inhibition led to diminished IFNγ production. Healthy humans carrying the longevity-associated FOXO3 single nucleotide polymorphism (SNP) rs12212067 exhibited reduced IFNγ and cytotoxic degranulation of NK cells. Viral inflammatory cardiomyopathy (viral CMI) patients with this SNP showed a poorer outcome due to less efficient virus control. Conclusion: Our results implicate Foxo3 in regulating NK cell function and suggest Foxo3 playing an important role in the antiviral innate immunity. Thus, enhanced FOXO3 activity such as in the polymorphism rs12212067 may be protective in chronic inflammation such as cancer and cardiovascular disease but disadvantageous to control acute viral infection.

Adiponectin attenuates profibrotic extracellular matrix remodeling following cardiac injury by up-regulating matrix metalloproteinase 9 expression in mice.

Adiponectin (APN) is a multifunctional adipocytokine that inhibits myocardial fibrosis, dilatation, and left ventricular (LV) dysfunction after myocardial infarction (MI). Coxsackievirus B3 (CVB3) myocarditis is associated with intense extracellular matrix (ECM) remodeling which might progress to dilated cardiomyopathy. Here, we investigated in experimental CVB3 myocarditis whether APN inhibits adverse ECM remodeling following cardiac injury by affecting matrix metalloproteinase (MMP) expression. Cardiac injury was induced by CVB3 infection in APN knockout (APN-KO) and wild-type (WT) mice. Expression and activity of MMPs was quantified by qRT-PCR and zymography, respectively. Activation of protein kinases was assessed by immunoblot. In cardiac myocytes and fibroblasts APN up-regulates MMP-9 expression via activation of 5' adenosine monophosphate-activated protein kinase (AMPK) and extracellular signal-regulated kinase (ERK)1/2 which function as master regulators of inflammation-induced MMP-9 expression. Correspondingly, APN further increased up-regulation of MMP-9 expression triggered by tumor necrosis factor (TNF)α, lipopolysaccharide (LPS) and R-848 in cardiac fibroblasts. In vivo, compared to WT mice cardiac MMP-9 activity and serum levels of carboxy-terminal telopeptide of type I collagen (ICTP) were attenuated in APN-KO mice in subacute (day 7 p.i.) CVB3 myocarditis. Moreover, on day 3 and day 7 post CVB3 infection splenic MMP-9 expression was diminished in APN-KO mice correlating with attenuated myocardial immune cell infiltration in subacute CVB3 myocarditis. These results indicate that APN attenuates adverse cardiac remodeling following cardiac injury by up-regulating MMP-9 expression in cardiac and immune cells. Thus, APN mediates intensified collagen cleavage that might explain inhibition of LV fibrosis and dysfunction.

Endothelin receptor polymorphisms in the cardiovascular system: potential implications for therapy and screening.

Since its discovery in 1988, the endothelin system has been employed in multiple physiological and pathological roles. Endothelin-1 (ET-1) is not only a major regulator of vascular tone and cardiac contractility but also exerts mitogenic effects and is involved in inflammatory responses. ET-1 acts via two endothelin receptors located mainly on smooth muscle and endothelial cells through complex intracellular pathways differing between receptors and cell types. Polymorphisms of the endothelin receptor A have been associated not only with the risk in pulmonary arterial hypertension (PAH), systolic heart failure and systemic hypertension but are also of prognostic significance in dilated cardiomyopathy. Polymorphisms of endothelin receptors might lead to altered endothelin signaling and influence the response to endothelin receptor antagonist therapy in PAH in light of pharmacogenetics. This review will summarize the role of ET-1 within major cardiovascular pathologies and discuss endothelin receptor polymorphisms with special emphasis on potential therapeutic and screening implications.