Impact of age over 70 years in the new allocation system on the outcomes of heart transplantation in the US.

BACKGROUND: United Network for Organ Sharing (UNOS) allocation criteria changed in 2018 to accommodate the increased prevalence of patients on a ventricular assist device as a bridge to heart transplant and prioritize sicker people in anticipation of a heart graft. We aimed to assess the impact of patient age in the new allocation policy on mortality following heart transplantation. Secondary outcomes included the effect of age ≥70 on post-transplant events, including stroke, dialysis, pacemaker, and rejection requiring treatment. METHODS: The UNOS Registry was queried to identify patients who underwent heart transplants alone in the US between 2000 and 2021. Patients were divided into groups according to their age (over 70 and under 70 years old). RESULTS: Patients aged over 70 were more likely to require dialysis during follow-up, but less likely to experience rejection requiring treatment, compared with patients aged <70. Age ≥70 in the new allocation system was a significant predictor of 1-year mortality (adjusted HR: 1.41; 95% CI: 1.05-1.91; p = .024), but its effect on 5-year mortality was not significant after adjusting for potential confounders (adjusted HR: 1.27; 95% CI:.97-1.66; p = .077). Undergoing transplantation under the new allocation policy vs the old allocation policy was not a significant predictor of mortality in patients over 70 years old. CONCLUSIONS: Age ≥70 is a significant predictor of 1-year mortality following heart transplantation, but not at 5 and 10 years; however, the new allocation does not seem to have changed the outcomes for this group of patients.

Deficiency of lncRNA MERRICAL abrogates macrophage chemotaxis and diabetes-associated atherosclerosis.

Diabetes-associated atherosclerosis involves excessive immune cell recruitment and plaque formation. However, the mechanisms remain poorly understood. Transcriptomic analysis of the aortic intima in Ldlr-/- mice on a high-fat, high-sucrose-containing (HFSC) diet identifies a macrophage-enriched nuclear long noncoding RNA (lncRNA), MERRICAL (macrophage-enriched lncRNA regulates inflammation, chemotaxis, and atherosclerosis). MERRICAL expression increases by 249% in intimal lesions during progression. lncRNA-mRNA pair genomic mapping reveals that MERRICAL positively correlates with the chemokines Ccl3 and Ccl4. MERRICAL-deficient macrophages exhibit lower Ccl3 and Ccl4 expression, chemotaxis, and inflammatory responses. Mechanistically, MERRICAL guides the WDR5-MLL1 complex to activate CCL3 and CCL4 transcription via H3K4me3 modification. MERRICAL deficiency in HFSC diet-fed Ldlr-/- mice reduces lesion formation by 74% in the aortic sinus and 86% in the descending aorta by inhibiting leukocyte recruitment into the aortic wall and pro-inflammatory responses. These findings unveil a regulatory mechanism whereby a macrophage-enriched lncRNA potently inhibits chemotactic responses, alleviating lesion progression in diabetes.

FAM222A, Part of the BET-Regulated Basal Endothelial Transcriptome, Is a Novel Determinant of Endothelial Biology and Angiogenesis-Brief Report.

BACKGROUND: BETs (bromodomain and extraterminal domain-containing epigenetic reader proteins), including BRD4 (bromodomain-containing protein 4), orchestrate transcriptional programs induced by pathogenic stimuli, as intensively studied in cardiovascular disease and elsewhere. In endothelial cells (ECs), BRD4 directs induced proinflammatory, proatherosclerotic transcriptional responses; BET inhibitors, like JQ1, repress these effects and decrease atherosclerosis. While BET effects in pathogenic conditions have prompted therapeutic BET inhibitor development, BET action under basal conditions, including ECs, has remained understudied. To understand BET action in basal endothelial transcriptional programs, we first analyzed EC RNA-Seq data in the absence versus presence of JQ1 before using BET regulation to identify novel determinants of EC biology and function. METHODS: RNA-Seq datasets of human umbilical vein ECs without and with JQ1 treatment were analyzed. After identifying C12orf34, also known as FAM222A (family with sequence similarity 222 member A), as a previously unreported, basally expressed, potently JQ1-induced EC gene, FAM222A was studied in endothelial and angiogenic responses in vitro using small-interference RNA silencing and lentiviral overexpression, in vitro, ex vivo and in vivo, including aortic sprouting, matrigel plug assays, and murine neonatal oxygen-induced retinopathy. RESULTS: Resting EC RNA-Seq data indicate BETs direct transcriptional programs underlying core endothelial properties including migration, proliferation, and angiogenesis. BET inhibition in resting ECs also significantly induced a subset of mRNAs, including FAM222A-a unique BRD4-regulated gene with no reported EC role. Silencing endothelial FAM222A significantly decreased cellular proliferation, migration, network formation, aorta sprouting, and Matrigel plug vascularization through coordinated modulation of VEGF (vascular endothelial growth factor) and NOTCH mediator expression in vitro, ex vivo, in vivo; lentiviral FAM222A overexpression had opposite effects. In vivo, siFAM222A significantly repressed retinal revascularization in neonatal murine oxygen-induced retinopathy through similar angiogenic signaling modulation. CONCLUSIONS: BET control over the basal endothelial transcriptome includes FAM222A, a novel, BRD4-regulated, key determinant of endothelial biology and angiogenesis.

Impact of new allocation system on length of stay following heart transplantation in the United States.

BACKGROUND: United Network for Organ Sharing (UNOS) allocation criteria changed in 2018 to accommodate the increased prevalence of ventricular assist device use as a bridge to heart transplant, which consequently prioritized sicker patients. We aimed to assess the impact of this new allocation policy on the length of stay following heart transplantation. Secondary outcomes include other risk factors for prolonged hospitalization and its effect on mortality and postoperative complications. METHODS: The UNOS Registry was queried to identify patients who underwent isolated heart transplants in the United States between 2001 and 2023. Patients were divided into quartiles according to their respective length of stay. RESULTS: A total of 57 020 patients were included, 15 357 of which were allocated with the new system. The median hospital length of stay was 15 days (mean 22.7 days). Length of stay was longer in the new allocation era (25 ± 30 vs. 22 ± 27 days, p < .001). The longer length of stay was associated with increased 5-year mortality in the new allocation system (aHR: 1.18; 95% CI: 1.15, 1.20; p-value: < .001). CONCLUSION: Longer hospital stays and associated observed increased risk for mortality in the era after the allocation criteria change reflect the rationale of this shift which was to prioritize heart transplants for sicker patients. Further studies are needed to track the progress of surgical and perioperative management of these studies over time.

Impaired angiogenesis in diabetic critical limb ischemia is mediated by a miR-130b/INHBA signaling axis.

Patients with peripheral artery disease (PAD) and diabetes compose a high-risk population for development of critical limb ischemia (CLI) and amputation, although the underlying mechanisms remain poorly understood. Comparison of dysregulated microRNAs from diabetic patients with PAD and diabetic mice with limb ischemia revealed the conserved microRNA, miR-130b-3p. In vitro angiogenic assays demonstrated that miR-130b rapidly promoted proliferation, migration, and sprouting in endothelial cells (ECs), whereas miR-130b inhibition exerted antiangiogenic effects. Local delivery of miR-130b mimics into ischemic muscles of diabetic mice (db/db) following femoral artery ligation (FAL) promoted revascularization by increasing angiogenesis and markedly improved limb necrosis and amputation. RNA-Seq and gene set enrichment analysis from miR-130b-overexpressing ECs revealed the BMP/TGF-ß signaling pathway as one of the top dysregulated pathways. Accordingly, overlapping downregulated transcripts from RNA-Seq and miRNA prediction algorithms identified that miR-130b directly targeted and repressed the TGF-ß superfamily member inhibin-ß-A (INHBA). miR-130b overexpression or siRNA-mediated knockdown of INHBA induced IL-8 expression, a potent angiogenic chemokine. Lastly, ectopic delivery of silencer RNAs (siRNA) targeting Inhba in db/db ischemic muscles following FAL improved revascularization and limb necrosis, recapitulating the phenotype of miR-130b delivery. Taken together, a miR-130b/INHBA signaling axis may provide therapeutic targets for patients with PAD and diabetes at risk of developing CLI.

A miRNA/CXCR4 signaling axis impairs monopoiesis and angiogenesis in diabetic critical limb ischemia.

Patients with peripheral artery disease (PAD) and diabetes have the highest risk of critical limb ischemia (CLI) and amputation, yet the underlying mechanisms remain incompletely understood. MicroRNA (miRNA) sequencing of plasma from diabetic patients with or without CLI was compared to diabetic mice with acute or subacute limb ischemia to identify conserved miRNAs. miRNA-KO mice on high-fat diet were generated to explore the impact on CLI. Comparison of dysregulated miRNAs from diabetic individuals with PAD and diabetic mice with limb ischemia revealed conserved miR-181 family members. High-fat-fed, diabetic Mir181a2b2-KO mice had impaired revascularization in limbs due to abrogation of circulating Ly6Chi monocytes, with reduced accumulation in ischemic skeletal muscles. M2-like KO macrophages under diabetic conditions failed to produce proangiogenic cytokines. Single-cell transcriptomics of the bone marrow niche revealed that the reduced monocytosis in diabetic KO mice was a result of impaired hematopoiesis, with increased CXCR4 signaling in bone marrow Lineage-Sca1+Kit+ (LSK) cells. Exogenous Ly6Chi monocytes from nondiabetic KO mice rescued the impaired revascularization in ischemic limbs of diabetic KO mice. Increased Cxcr4 expression was mediated by the miR-181 target, Plac8. Taken together, our results show that MiR-181a/b is a putative mediator of diabetic CLI and contributes to changes in hematopoiesis, monocytosis, and macrophage polarization.

Analysis of heart retransplantation outcomes in the new donor heart allocation system.

Cardiac graft failure may require repeat heart transplantation (HTx). Outcomes of patients that undergo repeat HTx have not been well described. We compared patients that received repeat HTx with patients that received initial HTx by inquiring the United Network for Organ Sharing (UNOS) database between 2015 and 2021. The primary endpoint was all-cause mortality, while the role of baseline characteristics was also investigated. Patients were stratified according to whether they received initial HTx (n = 19,727, 97%) or repeat HTx (n = 578, 3%). Among the study population, 10,860 (53.5%) patients received a HTx using the old UNOS allocation system, whereas 9445 (46.5%) patients received a HTx after the implementation of the new UNOS donor allocation system in October 2018. In this sub-group of HTx recipients in the new allocation system era, the adjusted 1-year survival of repeat HTx patients remained lower than that of initial HTx patients (hazard ratio (HR): 1.19; 95% confidence interval (CI): 1.15, 3.18; p = 0.013). When we compared the 1-year survival of repeat HTx patients before and after the implementation of the new allocation system, the adjusted 1-year survival was similar between groups (HR: 1.14; 95% CI: 0.71, 1.84; p = 0.591). The unadjusted risk of 30-day mortality was not significantly different in the new vs old allocation system. Mortality associated with repeat HTx remained higher than initial HTx but the new donor allocation system implementation did not affect outcomes.

Rejection Requiring Treatment within the First Year following Heart Transplantation: The UNOS Insight.

(1) Background: Heart failure is an extremely impactful health issue from both a social and quality-of-life point of view and the rate of patients with this condition is destined to rise in the next few years. Transplantation remains the mainstay of treatment for end-stage heart failure, but a shortage of organs represents a significant problem that prolongs time spent on the waiting list. In view of this, the selection of donor and recipient must be extremely meticulous, considering all factors that could predispose to organ failure. One of the main considerations regarding heart transplants is the risk of graft rejection and the need for immunosuppression therapy to mitigate that risk. In this study, we aimed to assess the characteristics of patients who need immunosuppression treatment for rejection within one year of heart transplantation and its impact on mid-term and long-term mortality. (2) Methods: The United Network for Organ Sharing (UNOS) Registry was queried to identify patients who solely underwent a heart transplant in the US between 2000 and 2021. Patients were divided into two groups according to the need for anti-rejection treatment within one year of heart transplantation. Patients' characteristics in the two groups were assessed, and 1 year and 10 year mortality rates were compared. (3) Results: A total of 43,763 patients underwent isolated heart transplantation in the study period, and 9946 (22.7%) needed anti-rejection treatment in the first year. Patients who required treatment for rejection within one year after transplant were more frequently younger (49 ± 14 vs. 52 ± 14 years, p < 0.001), women (31% vs. 23%, p < 0.001), and had a higher CPRA value (14 ± 26 vs. 11 ± 23, p < 0.001). Also, the rate of prior cardiac surgery was more than double in this group (27% vs. 12%, p < 0.001), while prior LVAD (12% vs. 11%, p < 0.001) and IABP (10% vs. 9%, p < 0.01) were more frequent in patients who did not receive anti-rejection treatment in the first year. Finally, pre-transplantation creatinine was significantly higher in patients who did not need treatment for rejection in the first year (1.4 vs. 1.3, p < 0.01). Most patients who did not require anti-rejection treatment underwent heart transplantation during the new allocation era, while less than half of the patients who required treatment underwent transplantation after the new allocation policy implementation (65% vs. 49%, p < 0.001). Patients who needed rejection treatment in the first year had a higher risk of unadjusted 1 year (HR: 2.25; 95% CI: 1.88-2.70; p < 0.001), 5 year (HR: 1.69; 95% CI: 1.60-1.79; p < 0.001), and 10 year (HR: 1.47; 95% CI: 1.41-1.54, p < 0.001) mortality, and this was confirmed at the adjusted analysis at all three time-points. (4) Conclusions: Medical treatment of acute rejection was associated with significantly increased 1 year mortality compared to patients who did not require anti-rejection therapy. The higher risk of mortality was confirmed at a 10 year follow-up. Further studies and newer follow-up data are required to investigate the role of anti-rejection therapy in the heart transplant population.

Transcriptomic and proteomic pathways of diabetic and non-diabetic mitochondrial transplantation.

Reduced mitochondrial function increases myocardial susceptibility to ischemia-reperfusion injury (IRI) in diabetic hearts. Mitochondrial transplantation (MT) ameliorates IRI, however, the cardioprotective effects of MT may be limited using diabetic mitochondria. Zucker Diabetic Fatty (ZDF) rats were subjected to temporary myocardial RI and then received either vehicle alone or vehicle containing mitochondria isolated from either diabetic ZDF or non-diabetic Zucker lean (ZL) rats. The ZDF rats were allowed to recover for 2 h or 28 days. MT using either ZDF- or ZL-mitochondria provided sustained reduction in infarct size and was associated with overlapping upregulation of pathways associated with muscle contraction, development, organization, and anti-apoptosis. MT using either ZDF- or ZL-mitochondria also significantly preserved myocardial function, however, ZL- mitochondria provided a more robust long-term preservation of myocardial function through the mitochondria dependent upregulation of pathways for cardiac and muscle metabolism and development. MT using either diabetic or non-diabetic mitochondria decreased infarct size and preserved functional recovery, however, the cardioprotection afforded by MT was attenuated in hearts receiving diabetic compared to non-diabetic MT.

Sex mismatch following heart transplantation in the United States: Characteristics and impact on outcomes.

BACKGROUND: Available literature indicates the possible detrimental effect of sex mismatching on mortality in patients undergoing heart transplantation. Our objective was to examine the role of sex and heart mass (predicted heart mass [PHM]) mismatch on mortality and graft rejection in patients undergoing heart transplantation in the US. METHODS: Data on adult patients who underwent heart transplantation between January 2015 and October 2021 were queried from the United Network of Organ Sharing (UNOS) registry. The main outcomes were all-cause mortality, 1-year all-cause mortality and treated acute rejection. RESULTS: A total of 19 805 adult patients underwent heart transplant during the study period. 92.2% of the patients in the female graft to male group had a PHM mismatch <25%, while only 38.5% had such a mismatch in the male graft to female group. In male to male and female to female groups, 79% and 76% of the patients had a PHM mismatch <25% (p = .122). Proportion of PHM mismatch was similar throughout the study period. Unadjusted analysis showed that male recipients of female grafts had increased risk for all-cause mortality (hazard ratio [HR]: 1.13; 95% confidence intervals [CI]: 1.02, 1.27; p = .026) and 1-year mortality (HR: 1.26; 95% CI: 1.09, 1.45; p = .002) compared to male recipients of male grafts. Graft failure incidence was also higher (HR: 1.12; 95% CI: 1.01, 1.25; p = .041). However, all these associations were non- significant after risk factor adjustment. CONCLUSIONS: Sex mismatching is associated with post-transplant mortality with transplantation of female donor grafts to male recipients demonstrating worse outcomes, although this association disappears after risk factor adjustment. Further research is required to elucidate the need for potential changes in clinical practice.

Percutaneous coronary intervention versus coronary artery bypass graft surgery in dialysis-dependent patients: A pooled meta-analysis of reconstructed time-to-event data.

OBJECTIVE: Το perform a systematic review with meta-analysis of published data comparing outcomes between a percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG) in dialysis-dependent patients. METHODS: We searched PubMed, Scopus, and Cochrane databases for studies including dialysis-dependent patients who underwent either CABG or PCI. This meta-analysis follows the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. We conducted one-stage and two-stage meta-analysis with Kaplan-Meier-derived individual patient data for overall survival and meta-analysis with the random-effects model for the in-hospital mortality and repeat revascularization. RESULTS: Twelve studies met our eligibility criteria, including 13,651 and 28,493 patients were identified in the CABG and PCI arms, respectively. Patients who underwent CABG had overall improved survival compared with those who underwent PCI at the one-stage meta-analysis (hazard ratio [HR]: 1.12, 95% confidence interval [CI]: 1.09-1.16, p < .0001) and the two-stage meta-analysis (HR: 1.15, 95% CI: 1.08-1.23, p < .001, I2 = 30.0%). Landmark analysis suggested that PCI offers better survival before the 8.5 months of follow-up (HR: 0.96, 95% CI: 0.92-0.99, p = .043), while CABG offers an advantage after this timepoint (HR: 1.3, 95% CI: 1.22-1.32, p < .001). CABG was associated with increased odds for in-hospital mortality (odds ratio [OR]: 1.70, 95% CI: 1.50-1.92, p < .001, I2 = 0.0%) and decreased odds for repeat revascularization (OR: 0.22, 95% CI: 0.14-0.34, p < .001, I2 = 58.08%). CONCLUSIONS: In dialysis-dependent patients, CABG was associated with long-term survival but a higher risk for early mortality. The risk for repeat revascularization was higher with PCI.

Perivascular Fibrosis Is Mediated by a KLF10-IL-9 Signaling Axis in CD4+ T Cells.

BACKGROUND: Perivascular fibrosis, characterized by increased amount of connective tissue around vessels, is a hallmark for vascular disease. Ang II (angiotensin II) contributes to vascular disease and end-organ damage via promoting T-cell activation. Despite recent data suggesting the role of T cells in the progression of perivascular fibrosis, the underlying mechanisms are poorly understood. METHODS: TF (transcription factor) profiling was performed in peripheral blood mononuclear cells of hypertensive patients. CD4-targeted KLF10 (Kruppel like factor 10)-deficient (Klf10fl/flCD4Cre+; [TKO]) and CD4-Cre (Klf10+/+CD4Cre+; [Cre]) control mice were subjected to Ang II infusion. End point characterization included cardiac echocardiography, aortic imaging, multiorgan histology, flow cytometry, cytokine analysis, aorta and fibroblast transcriptomic analysis, and aortic single-cell RNA-sequencing. RESULTS: TF profiling identified increased KLF10 expression in hypertensive human subjects and in CD4+ T cells in Ang II-treated mice. TKO mice showed enhanced perivascular fibrosis, but not interstitial fibrosis, in aorta, heart, and kidney in response to Ang II, accompanied by alterations in global longitudinal strain, arterial stiffness, and kidney function compared with Cre control mice. However, blood pressure was unchanged between the 2 groups. Mechanistically, KLF10 bound to the IL (interleukin)-9 promoter and interacted with HDAC1 (histone deacetylase 1) inhibit IL-9 transcription. Increased IL-9 in TKO mice induced fibroblast intracellular calcium mobilization, fibroblast activation, and differentiation and increased production of collagen and extracellular matrix, thereby promoting the progression of perivascular fibrosis and impairing target organ function. Remarkably, injection of anti-IL9 antibodies reversed perivascular fibrosis in Ang II-infused TKO mice and C57BL/6 mice. Single-cell RNA-sequencing revealed fibroblast heterogeneity with activated signatures associated with robust ECM (extracellular matrix) and perivascular fibrosis in Ang II-treated TKO mice. CONCLUSIONS: CD4+ T cell deficiency of Klf10 exacerbated perivascular fibrosis and multi-organ dysfunction in response to Ang II via upregulation of IL-9. Klf10 or IL-9 in T cells might represent novel therapeutic targets for treatment of vascular or fibrotic diseases.

Outcomes after heart transplantation in patients with cardiac sarcoidosis.

BACKGROUND: The number of patients with sarcoidosis requiring heart transplantation (HT) is increasing. The aim of this study was to evaluate outcomes of isolated HT in patients with sarcoid cardiomyopathy and compare them to recipients with non-ischaemic restrictive or dilated cardiomyopathy. METHODS AND RESULTS: Adult HT recipients were identified in the UNOS Registry between 1990 and 2020. Patients were grouped according to diagnosis. The cumulative incidences for the all-cause mortality and rejection were compared using Fine and Gray model analysis, accounting for re-transplantation as a competing risk. Rejection was evaluated using logistic regression analysis. We also reviewed characteristics and outcomes of all HT recipients with previous diagnosis of sarcoid cardiomyopathy from a single centre. A total of 30 160 HT recipients were included in the present study (n = 239 sarcoidosis, n = 1411 non-ischaemic restrictive cardiomyopathy, and n = 28 510 non-ischaemic dilated cardiomyopathy). During a total of 194 733 patient-years, all-cause mortality at the latest follow-up was not significantly different when comparing sarcoidosis to non-ischaemic dilated cardiomyopathy [adjusted subhazard ratio (aSHR) 1.46, 95% confidence intervals (CIs): 0.9-2.4, P = 0.12] or restrictive cardiomyopathy (aSHR 1.12, 95% CI: 0.65-1.95, P = 0.67). Accordingly, multivariable analysis suggested that 1 year mortality was not significantly different between sarcoidosis and non-ischaemic dilated cardiomyopathy (aSHR 1.56, 95% CI: 0.9-2.7, P = 0.12) or restrictive cardiomyopathy (aSHR 1.15, 95% CI: 0.61-2.18, P = 0.66). No differences were observed regarding 30 day mortality, treated and hospitalized acute rejection, and 30 day death from graft failure after HT. Thirty-day mortality did not improve significantly in more recent HT eras whereas there was a trend towards improved 1 year mortality in the latest HT era (P = 0.06). Data from the single-centre case review showed excellent long-term outcomes with sirolimus-based immunosuppression. CONCLUSIONS: Short-term and long-term post HT outcomes among patients with sarcoid cardiomyopathy are similar to those with common types of non-ischaemic cardiomyopathy.

Epicardial Adipocyte-derived TNF-α Modulates Local Inflammation in Patients with Advanced Coronary Artery Disease.

BACKGROUND: Epicardial Adipose Tissue (EAT) surrounds the epicardium and can mediate harmful effects related to Coronary Artery Disease (CAD). OBJECTIVE: We explored the regional differences between adipose stores surrounding diseased and non-diseased segments of coronary arteries in patients with advanced CAD. METHODS: We enrolled 32 patients with known CAD who underwent coronary artery bypass graft (CABG) surgery. Inflammatory mediators were measured in EAT biopsies collected from a region of the Left Anterior Descending Artery (LAD) with severe stenosis (diseased segment) and without stenosis (non-diseased segment). RESULTS: Mean age was 64.3±11.1 years, and mean EAT thickness was 7.4±1.9 mm. Dyslipidemia was the most prevalent comorbidity (81% of the patients). Out of a total of 11 cytokines, resistin (p=0.039), matrix metallopeptidase 9 (MMP-9) (p=0.020), C-C motif chemokine ligand 5 (CCL-5) (p=0.021), and follistatin (p=0.038) were significantly increased in the diseased compared with the non-diseased EAT segments. Indexed tumor necrosis factor-alpha (TNF-α), defined as the diseased to non-diseased cytokine levels ratio, was significantly correlated with increased EAT thickness both in the whole cohort (p=0.043) and in a subpopulation of patients with dyslipidemia (p=0.009). Treatment with lipid-lowering agents significantly decreased indexed TNF-α levels (p=0.015). No significant alterations were observed in the circulating levels of these cytokines with respect to CAD-associated comorbidities. CONCLUSION: Perivascular EAT is a source of cytokine secretion in distinct areas surrounding the coronary arteries in patients with advanced CAD. Adipocyte-derived TNF-α is a prominent mediator of local inflammation.

Surgical Treatment of Pulmonary Embolism and Chronic Thromboembolic Pulmonary Hypertension.

Venous thromboembolism clinically presents as deep venous thrombosis or acute pulmonary embolism and is globally recognized as the third most frequent acute cardiovascular syndrome after myocardial infarction and stroke. Although pulmonary embolism does not typically cause severe pulmonary hypertension in the acute setting, thrombus organization and fibrosis can lead to stenosis or obliteration of pulmonary arteries in a minority of patients, which in turn result in severe pulmonary hypertension and right heart failure. This disease is labeled chronic thromboembolic pulmonary hypertension and can occur after a single episode or multiple ones of pulmonary embolism. The cornerstone of pulmonary embolism treatment is medical therapy, whereas systemic thrombolytic therapy has to be considered for patients with hemodynamic instability. Given the current acceptable short-term surgical mortality, the potential of first-line surgical embolectomy as an alternative to medical thrombolysis has gained momentum as far as pulmonary embolism treatment is concerned. In contrast to pulmonary embolism, bilateral complete pulmonary endarterectomy under short deep hypothermic circulatory arrest intervals is the treatment of choice against chronic thromboembolic pulmonary hypertension, given patients' operability. Pulmonary endarterectomy is suggested in every operable patient when the operation is offered by an experienced multidisciplinary team, including at least one experienced surgeon. Surgical embolectomy should also be limited to large institutions since it also requires an experienced heart team. This review concerns a thorough discussion regarding surgical treatment of pulmonary embolism and chronic thromboembolic pulmonary hypertension. Eligibility criteria, operation-related complications and postoperative outcomes are discussed in detail.

Acute Kidney Injury Following Transcatheter Edge-to-Edge Mitral Valve Repair: A Systematic Review and Meta-Analysis.

BACKGROUND: Aim of this study was to perform a systematic review a meta-analysis of the literature in order to identify predictors of acute kidney injury (AKI) in patients with mitral regurgitation (MR) undergoing transcatheter edge-to-edge repair (TEER) and assess its effect on in-hospital outcomes and mortality. Although iodinated contrast is not typically used in TEER, these patients are still at risk for developing AKI. METHODS: Studies reporting on the effect of incident AKI on mortality following TEER for MR were included. Random-effects meta-analysis was performed, comparing clinical outcomes between the patients with or without incident AKI. RESULTS: Six studies including a total of 2057 patients (377 AKI and 1680 No-AKI) were included and analyzed. AKI was significantly associated with 30-day mortality after TEER (Odds ratio (OR): 8.06; 95% CI: 3.20, 20.30, p < 0.01; I2 = 18.4%) and all-cause mortality over a mean follow-up time of 30 months (Hazard ratio (HR): 2.48; 95% CI: 1.89, 3.24, p < 0.01; I2 = 23.7%). AKI after TEER was associated with prolonged hospitalization (Mean difference (in days): 1.41; 95% CI: 0.52, 2.31, p < 0.01; I2 = 82.4%). Stage 4 chronic kidney disease (CKD), device failure and history of chronic obstructive pulmonary disease (COPD) were significant predictors of AKI following TEER (CKD stage 4: OR: 2.38; 95% CI: 1.18, 4.78, p = 0.02; I2 = 0.0%; Device failure: OR: 3.15; 95% CI: 1.94, 5.12, p < 0.01; I2 = 0.0%; COPD: OR: 1.92; 95% CI: 1.16, 3.17; I2 = 26.7%). CONCLUSIONS: Our findings highlight the renal vulnerability of the TEER population to renal injury and the associated deterioration in clinical outcomes and survival.

Impact of induction therapy on outcomes after heart transplantation.

BACKGROUND: Approximately 50% of heart transplant (HT) programs utilize induction therapy (IT) with interleukin-2 receptor antagonists (IL2RA) or polyclonal anti-thymocyte antibodies (ATG). METHODS: Adult HT recipients were identified in the UNOS Registry between 2010 and 2020. We compared mortality between IT strategies with competing risk analysis. RESULTS: A total of 28 634 HT recipients were included in the study (50.1% no IT, 21.3% ATG, 27.9% IL2RA, .7% alemtuzumab, .01% OKT3). Adjusted all-cause, 30 day and 1 year mortality were lower among those treated with IT than no IT (sub-hazard ratio [SHR] .87, 95% CI .79-.96, SHR .86, .76-.97, SHR .76, .63-.93, P = .007, respectively). In propensity score matching analysis IT was associated with lower 30-day and 1-year mortality. IL2RA had higher all-cause and 1-year mortality than ATG (SHR 1.41, 95% CI 1.23-1.69 and 1.55, 95% CI 1.29-1.88, respectively). Utilization of IT was associated with significantly lower risk of treated rejection at 1 year after HT compared with no IT (relative risk ratio [RRR] .79) and similarly ATG compared with IL2RA (RRR .51). CONCLUSION: IT was associated with lower mortality and treated rejection episodes than no IT. IL2RA is the most used IT approach but ATG has lower risk of treated rejection and mortality.

State-of-the-art machine learning algorithms for the prediction of outcomes after contemporary heart transplantation: Results from the UNOS database.

PURPOSE: We sought to develop and validate machine learning (ML) models to increase the predictive accuracy of mortality after heart transplantation (HT). METHODS AND RESULTS: We included adult HT recipients from the United Network for Organ Sharing (UNOS) database between 2010 and 2018 using solely pre-transplant variables. The study cohort comprised 18 625 patients (53 ± 13 years, 73% males) and was randomly split into a derivation and a validation cohort with a 3:1 ratio. At 1-year after HT, there were 2334 (12.5%) deaths. Out of a total of 134 pre-transplant variables, 39 were selected as highly predictive of 1-year mortality via feature selection algorithm and were used to train five ML models. AUC for the prediction of 1-year survival was .689, .642, .649, .637, .526 for the Adaboost, Logistic Regression, Decision Tree, Support Vector Machine, and K-nearest neighbor models, respectively, whereas the Index for Mortality Prediction after Cardiac Transplantation (IMPACT) score had an AUC of .569. Local interpretable model-agnostic explanations (LIME) analysis was used in the best performing model to identify the relative impact of key predictors. ML models for 3- and 5-year survival as well as acute rejection were also developed in a secondary analysis and yielded AUCs of .629, .609, and .610 using 27, 31, and 91 selected variables respectively. CONCLUSION: Machine learning models showed good predictive accuracy of outcomes after heart transplantation.