The safe use of metformin in heart failure patients both with and without T2DM: A cross-sectional and longitudinal study.

AIMS: This study investigated the safe use of metformin in patients with (1) type 2 diabetes mellitus (T2DM) and heart failure on metformin, and (2) heart failure without T2DM and metformin naïve. METHODS: Two prospective studies on heart failure patients were undertaken. The first was a cross-sectional study with two patient cohorts, one with T2DM on metformin (n = 44) and one without T2DM metformin naive (n = 47). The second was a 12-week interventional study of patients without T2DM (n = 27) where metformin (500 mg immediate release, twice daily) was prescribed. Plasma metformin and lactate concentrations were monitored. Individual pharmacokinetics were compared between cohorts. Univariable and multivariable analysis analysed the effects of variables on plasma lactate concentrations. RESULTS: Plasma metformin and lactate concentrations mostly (99.9%) remained below safety thresholds (5 mg/L and 5 mmol/L, respectively). Metformin concentration had no significant relationship with lactic acidosis safety markers. In the interventional study, New York Heart Association (NYHA) II (P < .03) and III (P < .001) grading was associated with higher plasma lactate concentrations, whereas male sex was associated with 47% higher plasma lactate concentrations (P < .05). The pharmacokinetics of heart failure patients with and without T2DM were similar. CONCLUSIONS: We observed no unsafe plasma lactate concentrations in patients with heart failure treated with metformin. Metformin exposure did not influence plasma lactate concentrations, but NYHA class and sex did. The pharmacokinetics of metformin in heart failure patients are similar irrespective of T2DM. These findings may support the safe use of metformin in heart failure patients with and without T2DM.

COVID-19 and Acute Heart Failure: Screening the Critically Ill - A Position Statement of the Cardiac Society of Australia and New Zealand (CSANZ).

Up to one-third of COVID-19 patients admitted to intensive care develop an acute cardiomyopathy, which may represent myocarditis or stress cardiomyopathy. Further, while mortality in older patients with COVID-19 appears related to multi-organ failure complicating acute respiratory distress syndrome (ARDS), the cause of death in younger patients may be related to acute heart failure. Cardiac involvement needs to be considered early on in critically ill COVID-19 patients, and even after the acute respiratory phase is passing. This Statement presents a screening algorithm to better identify COVID-19 patients at risk for severe heart failure and circulatory collapse, while balancing the need to protect health care workers and preserve personal protective equipment (PPE). The significance of serum troponin levels and the role of telemetry and targeted transthoracic echocardiography (TTE) in patient investigation and management are addressed, as are fundamental considerations in the management of acute heart failure in COVID-19 patients.

Adult heart transplantation with distant procurement and ex-vivo preservation of donor hearts after circulatory death: a case series.

BACKGROUND: Orthotopic heart transplantation is the gold-standard long-term treatment for medically refractive end-stage heart failure. However, suitable cardiac donors are scarce. Although donation after circulatory death has been used for kidney, liver, and lung transplantation, it is not used for heart transplantation. We report a case series of heart transplantations from donors after circulatory death. METHODS: The recipients were patients at St Vincent's Hospital, Sydney, Australia. They received Maastricht category III controlled hearts donated after circulatory death from people younger than 40 years and with a maximum warm ischaemic time of 30 min. We retrieved four hearts through initial myocardial protection with supplemented cardioplegia and transferred to an Organ Care System (Transmedics) for preservation, resuscitation, and transportation to the recipient hospital. FINDINGS: Three recipients (two men, one woman; mean age 52 years) with low transpulmonary gradients (<8 mm Hg) and without previous cardiac surgery received the transplants. Donor heart warm ischaemic times were 28 min, 25 min, and 22 min, with ex-vivo Organ Care System perfusion times of 257 min, 260 min, and 245 min. Arteriovenous lactate values at the start of perfusion were 8·3-8·1 mmol/L for patient 1, 6·79-6·48 mmol/L for patient 2, and 7·6-7·4 mmol/L for patient 3. End of perfusion lactate values were 3·6-3·6 mmol/L, 2·8-2·3 mmol/L, and 2·69-2·54 mmol/L, respectively, showing favourable lactate uptake. Two patients needed temporary mechanical support. All three recipients had normal cardiac function within a week of transplantation and are making a good recovery at 176, 91, and 77 days after transplantation. INTERPRETATION: Strict limitations on donor eligibility, optimised myocardial protection, and use of a portable ex-vivo organ perfusion platform can enable successful, distantly procured orthotopic transplantation of hearts donated after circulatory death. FUNDING: NHMRC, John T Reid Charitable Trust, EVOS Trust Fund, Harry Windsor Trust Fund.

The Unpaceable Heart.

This is a case of flecainide toxicity in a patient with a permanent pacemaker. This case not only highlights the effects of flecainide toxicity on surface electrocardiography but how toxicity effects pacemaker function and its ability to transvenously pace the heart. The report provides some discussion of the management options for flecainide toxicity. (Level of Difficulty: Beginner.).

Comparison of continuous-flow ventricular assist device therapy with intensive medical therapy in fixed pulmonary hypertension secondary to advanced left heart failure.

AIMS: Both ventricular assist device (VAD) and pulmonary vasodilator therapy have been shown in uncontrolled studies to improve pulmonary hypertension secondary to advanced left heart failure (Group 2 PH). This study aimed to compare haemodynamic benefits and survival in patients with fixed Group 2 PH treated with continuous-flow VAD to intensive medical therapy. METHODS AND RESULTS: Ninety-five patients listed for heart transplantation with sequential right heart catheters were studied, 24 patients having fixed Group 2 PH (as defined by cardiac index < 2.8 L/min/m2 , pulmonary capillary wedge pressure > 15 mmHg, and transpulmonary gradient ≥ 15 mmHg or pulmonary vascular resistance > 3.0 WU, unresponsive to vasodilator challenge). Ten patients received VAD therapy, and 14 patients received standard heart failure therapy with or without sildenafil, nitrates, or endothelin receptor antagonists. At repeat right heart catheterization, patients treated with VAD therapy demonstrated significant improvement in both transpulmonary gradient (19 vs. 12 mmHg, P = 0.046) and pulmonary vascular resistance (6.5 vs. 2.9 WU, P = 0.003) compared with baseline, while those treated with medical therapy did not (20.9 vs. 20.3 mmHg and 6.5 vs. 6.4 WU, P = NS for both). Patients who received VAD therapy were significantly more likely to achieve normalized transpulmonary gradient (8/10 vs. 4/14, P = 0.013) and were more likely to be listed for orthotopic heart transplantation (7/10 vs. 4/14, P < 0.05). There were no significant differences between groups in terms of all-cause mortality. CONCLUSIONS: Continuous-flow VAD therapy more effectively reverses fixed Group 2 PH compared with medical therapy alone and may allow a higher rate of listing for orthotopic heart transplantation.

Improved heart function from older donors using pharmacologic conditioning strategies.

BACKGROUND: Hearts from older donors are increasingly being referred for transplantation. However, these hearts are more susceptible to ischemia-reperfusion injury (IRI), reflected in higher rates of primary graft dysfunction. We assessed a strategy of pharmacologic conditioning, supplementing Celsior (Genzyme, Naarden, The Netherlands) preservation solution with glyceryl trinitrate (GTN; Hospira Australia Pty, Ltd, Mulgrave, VIC, Australia), erythropoietin (EPO; Eprex; Janssen-Cilag, North Ryde, NSW, Australia), and zoniporide (ZON; Pfizer, Inc., Groton, CT), to protect older hearts against IRI and improve graft function. METHODS: Wistar rats, aged 3, 12, and 18 months old, were used to represent adolescent, 30-year-old, and 45-year-old human donors, respectively. Animals were subjected to brain death (BD) and hearts stored for 6 hours at 2° to 3°C in Celsior or Celsior supplemented with GTN+EPO+ZON. Cardiac function and lactate dehydrogenase before and after storage were assessed during ex vivo perfusion. Western blots and histopathology were also analyzed. RESULTS: After BD, 18-month hearts demonstrated impaired aortic flow, coronary flow, and cardiac output compared with 3-month hearts (p < 0.001 to p < 0.0001). After storage in Celsior, the recovery of aortic flow, coronary flow, and cardiac output in 18-month BD hearts was further impaired (p < 0.01 vs 3-month hearts). Percentage functional recovery of 18-month BD hearts stored in Celsior supplemented with GTN+EPO+ZON was equivalent to that of 3-month hearts and significantly improved compared with 18-month hearts stored in Celsior alone (p < 0.01 to p < 0.001), with reduced lactate dehydrogenase release (p < 0.01) and myocardial edema (p < 0.05) and elevated phosphorylated extracellular signal-related kinase 1/2 (p < 0.05) and phosphorylated Akt (p < 0.01). CONCLUSIONS: Older hearts are more susceptible to IRI induced by BD and prolonged hypothermic storage. Supplemented Celsior activates cell survival signaling in older hearts, reduces IRI, and enhances donor heart preservation.

Pathophysiological Trends During Withdrawal of Life Support: Implications for Organ Donation After Circulatory Death.

BACKGROUND: Donation after circulatory death (DCD) provides an alternative pathway to deceased organ transplantation. Although clinical DCD lung, liver, and kidney transplantation are well established, transplantation of hearts retrieved from DCD donors has reached clinical translation only recently. Progress has been limited by concern regarding the viability of DCD hearts. The aim of this study was to document the pathophysiological changes that occur in the heart and circulation during withdrawal of life (WLS) support. METHODS: In a porcine asphyxia model, we characterized the hemodynamic, volumetric, metabolic, biochemical, and endocrine changes after WLS for up to 40 minutes. Times to circulatory arrest and electrical asystole were recorded. RESULTS: After WLS, there was rapid onset of profound hypoxemia resulting in acute pulmonary hypertension and right ventricular distension. Concurrently, progressive systemic hypotension occurred with a fall in left atrial pressure and little change in left ventricular volume. Mean times to circulatory arrest and electrical asystole were 8 ± 1 and 16 ± 2 minutes, respectively. Hemodynamic changes were accompanied by a rapid fall in pH, and rise in blood lactate, troponin-T, and potassium. Plasma noradrenaline and adrenaline levels rose rapidly with dramatic increases in coronary sinus levels indicative of myocardial release. CONCLUSIONS: These findings provide insight into the nature and tempo of the damaging events that occur in the heart and in particular the right ventricle during WLS, and give an indication of the limited timeframe for the implementation of potential postmortem interventions that could be applied to improve organ viability.

HLA class I associations with EBV+ post-transplant lymphoproliferative disorder.

Epstein-Barr virus (EBV) is frequently associated with post-transplant lymphoproliferative disorders (EBV(+) PTLD). In these cases, impaired Epstein-Barr virus (EBV)-specific CD8(+) T-cell immunity is strongly implicated and antigen presentation within the malignant B-cell is intact. Interestingly, several studies have reported HLA class I alleles with protective or susceptibility associations. However, results are conflicting, likely influenced by methodology including inconsistent use of multiple hypothesis testing. By contrast, HLA class I associations have been repeatedly reported for classical Hodgkin Lymphoma (cHL), in which EBV is also implicated in a proportion of cases. In contrast to EBV(+) PTLD which expresses the immunodominant EBV latency III EBNA3A/B/C proteins, EBV(+) cHL is restricted to the subdominant EBNA1/LMP1/LMP2 proteins. Herein, we report a study of HLA class I associations in EBV(+) PTLD, with 263 patients with lymphoma (cHL or PTLD) evaluated. Two Australian population cohorts, n = 23,736 and n = 891 were used for comparison. Contrary to previous reports, no HLA class I associations with EBV(+) PTLD were found, whereas for cHL known HLA class I associations were confirmed, with HLA-A*02 homozygous individuals having the lowest odds of developing EBV(+) cHL. Our results suggest that HLA class I does not influence susceptibility to the viral latency III expressing lymphoma, EBV(+) PTLD. Further studies are required for definitive confirmation.

Post-transplant lymphoproliferative disease in heart and lung transplantation: Defining risk and prognostic factors.

BACKGROUND: Heart and lung transplant recipients have among of the highest incidence rates of post-transplant lymphoproliferative disease (PTLD). Despite this, there is a paucity of data specific to this group. We collated data on heart, lung and heart-lung transplant recipients with PTLD to identify disease features and prognostic factors unique to this group of patients. METHODS: Seventy cases of PTLD were identified from a single institution (41 heart, 22 lung, 6 heart-lung and 1 heart-kidney transplant) from 1984 to 2013. Demographics, immunosuppression, treatment, response, complications and survival data were analyzed. Uni- and multivariate Cox regression analyses were performed to identify prognostic factors. RESULTS: The incidence of PTLD was 7.59% in heart-lung, 5.37% in heart and 3.1% in lung transplant recipients. Extranodal disease (82%) with diffuse large B-cell lymphoma (72%) was the most common presentation. Bone marrow involvement (13%) and central nervous system disease (3%) were uncommon. Heart transplant recipients had later onset of PTLD (>1 year post-transplant), with less allograft involvement, compared with lung and heart-lung recipients. Poor prognostic markers were bone marrow involvement (HR 6.75, p < 0.001) and serum albumin <30 g/liter (HR 3.18, p = 0.006). Improved survival was seen with a complete response within 3 months of treatment (HR 0.08, p < 0.001). Five-year overall survival was 29%. CONCLUSION: This analysis is the largest to date on PTLD in heart and lung transplant recipients. It provides a detailed analysis of the disease in this group of patients and identifies unique prognostic features to aid risk stratification and guide treatment allocation.

Imatinib for the treatment of pulmonary arterial hypertension and pulmonary capillary hemangiomatosis.

Despite currently available treatments, the prognoses of pulmonary arterial hypertension (PAH) and pulmonary capillary hemangiomatosis (PCH) remain poor. Platelet-derived growth factor and its receptor (PDGFR) have been implicated in the pathogenesis of pulmonary hypertension in PAH and PCH. Imatinib, a PDGFR antagonist, may be beneficial in the treatment of both conditions because of its potent antiproliferative effect. We report two cases that demonstrate the potential for safe and efficacious use of imatinib in PAH and PCH.

Primary graft failure after heart transplantation.

Primary graft failure (PGF) is a devastating complication that occurs in the immediate postoperative period following heart transplantation. It manifests as severe ventricular dysfunction of the donor graft and carries significant mortality and morbidity. In the last decade, advances in pharmacological treatment and mechanical circulatory support have improved the outlook for heart transplant recipients who develop this complication. Despite these advances in treatment, PGF is still the leading cause of death in the first 30 days after transplantation. In today's climate of significant organ shortages and growing waiting lists, transplant units worldwide have increasingly utilised "marginal donors" to try and bridge the gap between "supply and demand." One of the costs of this strategy has been an increased incidence of PGF. As the threat of PGF increases, the challenges of predicting and preventing its occurrence, as well as the identification of more effective treatment modalities, are vital areas of active research and development.