COVID-19 Associated Pulmonary Aspergillosis in Patients on Extracorporeal Membrane Oxygenation Treatment-A Retrospective Study.

BACKGROUND: The incidence and outcome of pulmonary aspergillosis in coronavirus disease (COVID-19) patients on extracorporeal membrane oxygenation (ECMO) are unknown and have not been fully addressed. We investigated the incidence, risk factors and outcome of pulmonary aspergillosis in COVID-19 ECMO patients. In addition, the diagnostic utility of bronchoalveolar lavage fluid and CT scans in this setting were assessed. METHODS: We conducted a retrospective study on incidence and outcome of pulmonary aspergillosis in COVID-19 ECMO patients by reviewing clinical, radiological, and mycological evidence. These patients were admitted to a tertiary cardiothoracic centre during the early COVID-19 surge between March 2020 and January 2021. Results and measurements: The study included 88 predominantly male COVID-19 ECMO patients with a median age and a BMI of 48 years and 32 kg/m2, respectively. Pulmonary aspergillosis incidence was 10% and was associated with very high mortality. Patients with an Aspergillus infection were almost eight times more likely to die compared with those without infection in multivariate analysis (OR 7.81, 95% CI: 1.20-50.68). BALF GM correlated well with culture results, with a Kappa value of 0.8 (95% CI: 0.6, 1.0). However, serum galactomannan (GM) and serum (1-3)-ß-D-glucan (BDG) lacked sensitivity. Thoracic computed tomography (CT) diagnostic utility was also inconclusive, showing nonspecific ground glass opacities in almost all patients. CONCLUSIONS: In COVID-19 ECMO patients, pulmonary aspergillosis incidence was 10% and associated with very high mortality. Our results support the role of BALF in the diagnosis of pulmonary aspergillosis in COVID-19 ECMO patients. However, the diagnostic utility of BDG, serum GM, and CT scans is unclear.

Optimal dose of adrenaline auto-injector for children and young people at risk of anaphylaxis: A phase IV randomized controlled crossover study.

BACKGROUND: Guidelines recommend intramuscular injection of 500 µg adrenaline (epinephrine) for anaphylaxis in teenagers and adults; however, most autoinjectors deliver a maximum 300 µg dose. We evaluated plasma adrenaline levels and cardiovascular parameters (including cardiac output) following self-injection with 300 µg or 500 µg adrenaline in teenagers at risk of anaphylaxis. METHODS: Subjects were recruited to a randomized, single-blind two period crossover trial. Participants received all 3 injections (Emerade® 500 µg, Emerade® 300 µg, Epipen® 0.3 mg) on 2 separate visits (allocated in a randomized block design), at least 28 days apart. Intramuscular injection was confirmed by ultrasound, and heart rate/stroke volume assessed using continuous monitoring. The trial was registered at Clinicaltrials.gov (NCT03366298). RESULTS: Twelve participants (58% male, median 15.4 years) participated; all completed the study. 500 µg injection resulted in a higher and more prolonged peak concentration (p = 0.01) and greater Area-Under-Curve for plasma adrenaline (p < 0.05) compared to 300 µg, with no difference in adverse events. Adrenaline caused a significant increase in heart rate irrespective of dose and device. Unexpectedly, 300 µg adrenaline resulted in a significant increase in stroke volume when delivered with Emerade®, but a negative inotropic effect with Epipen® (p < 0.05). CONCLUSIONS: These data support a 500 µg dose of adrenaline to treat anaphylaxis in individuals >40 kg in the community. The contrasting effects on stroke volume between Epipen® and Emerade®, despite similar peak plasma adrenaline levels, are unexpected. There is an urgent need to better understand differences in pharmacodynamics following adrenaline administration by autoinjector. In the meantime, we recommend adrenaline injection by needle/syringe in the healthcare setting in individuals with anaphylaxis refractory to initial treatment.

Complement activation during cardiopulmonary bypass and association with clinical outcomes.

In this prospective, single-centre observational study of 30 patients undergoing cardiopulmonary bypass (CPB), the effect of unfractionated heparin (UFH), CPB surgery and protamine sulphate on complement and on post-operative blood loss were assessed. Although C3 and C4 levels decreased significantly immediately following the administration of UFH, C3a, C5a, Bb fragment and SC5b-9 remained unchanged. During CPB, C3 and C4 continued to fall whilst both alternative and classical pathways activation markers, Bb, C3a, C5a and SC5b-9 increased significantly. Protamine sulphate had no effect on classical pathway components or activation markers but decreased alternative pathway activation marker Bb. Over the 12-24 h post-surgery, both classical and alternative pathway activation markers returned to baseline, whilst C3 and C4 levels increased significantly but not to baseline values. Total drain volume 24 h after the surgery showed a moderate inverse correlation with post-protamine C3 (r = -0.46, p = 0.01) and C4 (r = -0.57, p = 0.0009) levels, whilst a moderate positive correlation was observed with post-protamine C3a (r = 0.46, p = 0.009), C5a (r = 0.37, p = 0.04) and SC5b-9 (r = 0.56, p = 0.001) levels but not with Bb fragment (r = 0.25, p = 0.17). Thus, inhibition of complement activation may be a therapeutic intervention to reduce post-operative blood in patients undergoing CPB.

Precision Phenotyping of Dilated Cardiomyopathy Using Multidimensional Data.

BACKGROUND: Dilated cardiomyopathy (DCM) is a final common manifestation of heterogenous etiologies. Adverse outcomes highlight the need for disease stratification beyond ejection fraction. OBJECTIVES: The purpose of this study was to identify novel, reproducible subphenotypes of DCM using multiparametric data for improved patient stratification. METHODS: Longitudinal, observational UK-derivation (n = 426; median age 54 years; 67% men) and Dutch-validation (n = 239; median age 56 years; 64% men) cohorts of DCM patients (enrolled 2009-2016) with clinical, genetic, cardiovascular magnetic resonance, and proteomic assessments. Machine learning with profile regression identified novel disease subtypes. Penalized multinomial logistic regression was used for validation. Nested Cox models compared novel groupings to conventional risk measures. Primary composite outcome was cardiovascular death, heart failure, or arrhythmia events (median follow-up 4 years). RESULTS: In total, 3 novel DCM subtypes were identified: profibrotic metabolic, mild nonfibrotic, and biventricular impairment. Prognosis differed between subtypes in both the derivation (P < 0.0001) and validation cohorts. The novel profibrotic metabolic subtype had more diabetes, universal myocardial fibrosis, preserved right ventricular function, and elevated creatinine. For clinical application, 5 variables were sufficient for classification (left and right ventricular end-systolic volumes, left atrial volume, myocardial fibrosis, and creatinine). Adding the novel DCM subtype improved the C-statistic from 0.60 to 0.76. Interleukin-4 receptor-alpha was identified as a novel prognostic biomarker in derivation (HR: 3.6; 95% CI: 1.9-6.5; P = 0.00002) and validation cohorts (HR: 1.94; 95% CI: 1.3-2.8; P = 0.00005). CONCLUSIONS: Three reproducible, mechanistically distinct DCM subtypes were identified using widely available clinical and biological data, adding prognostic value to traditional risk models. They may improve patient selection for novel interventions, thereby enabling precision medicine.

Experience of Isavuconazole as a Salvage Therapy in Chronic Pulmonary Fungal Disease.

Background: Instances of resistant fungal infection are rising in pulmonary disease, with limited therapeutic options. Therapeutic drug monitoring of azole antifungals has been necessary to ensure safety and efficacy but is considered unnecessary for the newest triazole isavuconazole. Aims: To characterise the prevalence of isavuconazole resistance and use in a tertiary respiratory centre. Methods: A retrospective observational analysis (2016−2021) of adult respiratory patients analysing fungal culture, therapeutic drug monitoring, and outcome post-isavuconazole therapy. Results: During the study period, isavuconazole susceptibility testing was performed on 26 Aspergillus spp. isolates. A total of 80.8% of A. fumigatus isolates had isavuconazole (MIC > 1 mg/L, and 73.0% > 2 mg/L) with a good correlation to voriconazole MIC (r = 0.7, p = 0.0002). A total of 54 patients underwent isavuconazole therapy during the study period (median duration 234 days (IQR: 24−499)). A total of 67% of patients tolerated isavuconazole, despite prior azole toxicity in 61.8%, with increased age (rpb = 0.31; p = 0.021) and male sex (φc = 0.30; p = 0.027) being associated with toxicity. A total of 132 isavuconazole levels were performed with 94.8% > 1 mg/L and 72% > 2 mg/L. Dose change from manufacturer's recommendation was, however, required in 9.3% to achieve a concentration of >2 mg/L. Conclusion: We describe the use of isavuconazole as a salvage therapy in a chronic pulmonary fungal disease setting with a high prevalence of azole resistance. Therapeutic concentrations at standard dosing were high; however, results reinforce antifungal stewardship for optimization.

Clinical pharmacokinetics and dose recommendations for posaconazole gastroresistant tablets in children with cystic fibrosis.

OBJECTIVES: To investigate the population pharmacokinetics of posaconazole gastroresistant tablets in children with cystic fibrosis (CF) and perform simulations to recommend optimal doses. PATIENTS AND METHODS: Children from a paediatric CF centre who had received posaconazole tablets and underwent therapeutic drug monitoring were identified from pharmacy records. Relevant clinical data were collated from case notes and electronic patient records and used to develop an allometrically scaled population pharmacokinetic model. A stepwise covariate model-building exercise evaluated the influence of interacting medicines and liver function. RESULTS: One hundred posaconazole serum concentrations were collected from 37 children with a median age of 14 years (range 7-17). Posaconazole pharmacokinetics were adequately described by a one-compartment model with inter-individual variability on clearance. Dose simulations demonstrated a 77%-83% probability of attaining a trough target of 1 mg/L with a dose of 300 mg every 12 h for two doses then 300 mg once daily (OD) in children aged 6-11 years; and 86%-88% with a dose of 400 mg every 12 h for two doses then 400 mg OD in adolescents aged 12-17 years. This dose scheme also yielded a 90% probability of achieving an AUC of 30 mg·h/L. AUC and trough concentration were highly correlated (r2 = 0.98). Simulations showed that trough concentrations of >0.75 mg/L would exceed an AUC of 30 mg·h/L in 90% of patients. CONCLUSIONS: A starting dose of 300 mg OD in those aged 6-11 years and 400 mg OD in those aged 12-17 years (following loading doses) yields a 90% probability of attaining an AUC of 30 mg·h/L.

Utilisation of remote capillary blood testing in an outpatient clinic setting to improve shared decision making and patient and clinician experience: a validation and pilot study.

BACKGROUND: In a tertiary respiratory centre, large cohorts of patients are managed in an outpatient setting and require blood tests to monitor disease activity and organ toxicity. This requires either visits to tertiary centres for phlebotomy and physician review or utilisation of primary care services. OBJECTIVES: This study aims to validate remote capillary blood testing in an outpatient setting and analyse impact on clinical pathways. METHODS: A single-centre prospective cross-sectional validation and parallel observational study was performed. Remote finger prick capillary blood testing was validated compared with local standard venesection using comparative statistical analysis: paired t-test, correlation and Bland-Altman. Capillary was considered interchangeable with venous samples if all three criteria were met: non-significant paired t-test (ie, p>0.05), Pearson's correlation coefficient (r)>0.8% and 95% of tests within 10% difference through Bland-Altman (limits of agreement). In parallel, current clinical pathways including phlebotomy practice were analysed over 4 weeks to review test predictability. A subsequent pilot cohort study analysed potential impact of remote capillary blood sampling on shared decision making. A final implementation phase ensued to embed the service into clinical pathways within the institution. RESULTS: 117 paired capillary and venous blood samples were prospectively analysed. Interchangeability with venous blood was seen with glycated haemoglobin (%), total protein and C reactive protein. Further tests, although not interchangeable, are likely useful to enable longitudinal remote monitoring (eg, liver function and total IgE). 65% of outpatient clinic blood tests were predictable with 16% of patients requiring further follow-up. Patient and clinician-reported improvement in shared decision making given contemporaneous blood test results was observed. CONCLUSIONS: Remote capillary blood sampling can be used accurately for specific tests to monitor chronic disease, and when incorporated into an outpatient clinical pathway can improve shared decision making and patient experience. Further research is required to determine health economic impact and applicability within telemedicine-based outpatient care.

Serum markers of pulmonary epithelial damage in systemic sclerosis-associated interstitial lung disease and disease progression.

BACKGROUND AND OBJECTIVE: The course of systemic sclerosis-associated interstitial lung disease (SSc-ILD) is highly variable, and accurate prognostic markers are needed. KL-6 is a mucin-like glycoprotein (MUC1) expressed by type II pneumocytes, while CYFRA 21-1 is expressed by alveolar and bronchiolar epithelial cells. Both are released into the blood from cell injury. METHODS: Serum KL-6 and CYFRA 21-1 levels were measured in a retrospective (n = 189) and a prospective (n = 118) cohort of SSc patients. Genotyping of MUC1 rs4072037 was performed. Linear mixed-effect models were used to evaluate the relationship with change in lung function parameters over time, while association with survival was evaluated with Cox proportional hazard analysis. RESULTS: In both cohorts, KL-6 and CYFRA 21-1 were highest in patients with lung involvement, and in patients with extensive rather than limited ILD. KL-6 was higher in patients carrying the MUC1 rs4072037 G allele in both cohorts. In patients with SSc-ILD, serum KL-6, but not CYFRA 21-1, was significantly associated with DLCO decline in both cohorts (P = 0.001 and P = 0.004, respectively), and with FVC decline in the retrospective cohort (P = 0.005), but not the prospective cohort. When combining the cohorts and subgrouping by severity (median CPI = 45.97), KL-6 remained predictive of decline in DLCO in both milder (P = 0.007) and more severe disease (P = 0.02) on multivariable analysis correcting for age, gender, ethnicity, smoking history and MUC1 allele carriage. CONCLUSION: Our results suggest serum KL-6 predicts decline in lung function in SSc, suggesting its clinical utility in risk stratification for progressive SSc-ILD.

Utility of routine screening for alpha-1 antitrypsin deficiency in patients with bronchiectasis.

Alpha-1 antitrypsin deficiency (AATD) is a cause of bronchiectasis. Guidelines for bronchiectasis from the British Thoracic Society do not recommend to routinely test patients for AATD. In contrast, guidelines for AATD recommend routine screening. This contradiction, in part, results from the lack of data from large studies performing comprehensive screening. We screened 1600 patients with bronchiectasis at two centres in the UK from 2012 to 2016. In total, only eight individuals with AATD were identified representing 0.5% of the overall population. We conclude that routine screening for AATD in bronchiectasis in the UK has a low rate of detection. Further studies are required in different geographical regions, which may have a higher prevalence of AATD.

Osteoprotegerin and Myocardial Fibrosis in Patients with Aortic Stenosis.

Left ventricular myocardial fibrosis in patients with aortic stenosis (AS) confers worse prognosis. Plasma osteoprotegerin (OPG), a cytokine from the TNF receptor family, correlates with the degree of valve calcification in AS, reflecting the activity of the tissue RANKL/RANK/OPG (receptor activator of nuclear factor κΒ ligand/RANK/osteoprotegerin) axis, and is associated with poorer outcomes in AS. Its association with myocardial fibrosis is unknown. We hypothesised that OPG levels would reflect the extent of myocardial fibrosis in AS. We included 110 consecutive patients with AS who had undergone late-gadolinium contrast enhanced cardiovascular magnetic resonance (LGE-CMR). Patients were characterised according to pattern of fibrosis (no fibrosis, midwall fibrosis, or chronic myocardial infarction fibrosis). Serum OPG was measured with ELISA and compared between groups defined by valve stenosis severity. Some 36 patients had no fibrosis, 38 had midwall fibrosis, and 36 had chronic infarction. Patients with midwall fibrosis did not have higher levels of OPG compared to those without fibrosis (6.78 vs. 5.25 pmol/L, p = 0.12). There was no difference between those with midwall or chronic myocardial infarction fibrosis (6.78 vs. 6.97 pmol/L, p = 0.27). However, OPG levels in patients with chronic myocardial infarction fibrosis were significantly higher than those without fibrosis (p = 0.005).

Lipoprotein(a) in patients with aortic stenosis: Insights from cardiovascular magnetic resonance.

BACKGROUND: Aortic stenosis is the most common age-related valvular pathology. Patients with aortic stenosis and myocardial fibrosis have worse outcome but the underlying mechanism is unclear. Lipoprotein(a) is associated with adverse cardiovascular risk and is elevated in patients with aortic stenosis. Although mechanistic pathways could link Lipoprotein(a) with myocardial fibrosis, whether the two are related has not been previously explored. In this study, we investigated whether elevated Lipoprotein(a) was associated with the presence of myocardial replacement fibrosis. METHODS: A total of 110 patients with mild, moderate and severe aortic stenosis were assessed by late gadolinium enhancement (LGE) cardiovascular magnetic resonance to identify fibrosis. Mann Whitney U tests were used to assess for evidence of an association between Lp(a) and the presence or absence of myocardial fibrosis and aortic stenosis severity and compared to controls. Univariable and multivariable linear regression analysis were undertaken to identify possible predictors of Lp(a). RESULTS: Thirty-six patients (32.7%) had no LGE enhancement, 38 (34.6%) had midwall enhancement suggestive of midwall fibrosis and 36 (32.7%) patients had subendocardial myocardial fibrosis, typical of infarction. The aortic stenosis patients had higher Lp(a) values than controls, however, there was no significant difference between the Lp(a) level in mild, moderate or severe aortic stenosis. No association was observed between midwall or infarction pattern fibrosis and Lipoprotein(a), in the mild/moderate stenosis (p = 0.91) or severe stenosis patients (p = 0.42). CONCLUSION: There is no evidence to suggest that higher Lipoprotein(a) leads to increased myocardial midwall or infarction pattern fibrosis in patients with aortic stenosis.

Repeated nebulisation of non-viral CFTR gene therapy in patients with cystic fibrosis: a randomised, double-blind, placebo-controlled, phase 2b trial.

BACKGROUND: Lung delivery of plasmid DNA encoding the CFTR gene complexed with a cationic liposome is a potential treatment option for patients with cystic fibrosis. We aimed to assess the efficacy of non-viral CFTR gene therapy in patients with cystic fibrosis. METHODS: We did this randomised, double-blind, placebo-controlled, phase 2b trial in two cystic fibrosis centres with patients recruited from 18 sites in the UK. Patients (aged ≥12 years) with a forced expiratory volume in 1 s (FEV1) of 50-90% predicted and any combination of CFTR mutations, were randomly assigned, via a computer-based randomisation system, to receive 5 mL of either nebulised pGM169/GL67A gene-liposome complex or 0.9% saline (placebo) every 28 days (plus or minus 5 days) for 1 year. Randomisation was stratified by % predicted FEV1 (<70 vs ≥70%), age (<18 vs ≥18 years), inclusion in the mechanistic substudy, and dosing site (London or Edinburgh). Participants and investigators were masked to treatment allocation. The primary endpoint was the relative change in % predicted FEV1. The primary analysis was per protocol. This trial is registered with ClinicalTrials.gov, number NCT01621867. FINDINGS: Between June 12, 2012, and June 24, 2013, we randomly assigned 140 patients to receive placebo (n=62) or pGM169/GL67A (n=78), of whom 116 (83%) patients comprised the per-protocol population. We noted a significant, albeit modest, treatment effect in the pGM169/GL67A group versus placebo at 12 months' follow-up (3.7%, 95% CI 0.1-7.3; p=0.046). This outcome was associated with a stabilisation of lung function in the pGM169/GL67A group compared with a decline in the placebo group. We recorded no significant difference in treatment-attributable adverse events between groups. INTERPRETATION: Monthly application of the pGM169/GL67A gene therapy formulation was associated with a significant, albeit modest, benefit in FEV1 compared with placebo at 1 year, indicating a stabilisation of lung function in the treatment group. Further improvements in efficacy and consistency of response to the current formulation are needed before gene therapy is suitable for clinical care; however, our findings should also encourage the rapid introduction of more potent gene transfer vectors into early phase trials. FUNDING: Medical Research Council/National Institute for Health Research Efficacy and Mechanism Evaluation Programme.

Hypoalbuminaemia predicts outcome in adult patients with congenital heart disease.

BACKGROUND: In patients with acquired heart failure, hypoalbuminaemia is associated with increased risk of death. The prevalence of hypoproteinaemia and hypoalbuminaemia and their relation to outcome in adult patients with congenital heart disease (ACHD) remains, however, unknown. METHODS: Data on patients with ACHD who underwent blood testing in our centre within the last 14 years were collected. The relation between laboratory, clinical or demographic parameters at baseline and mortality was assessed using Cox proportional hazards regression analysis. RESULTS: A total of 2886 patients with ACHD were included. Mean age was 33.3 years (23.6-44.7) and 50.1% patients were men. Median plasma albumin concentration was 41.0 g/L (38.0-44.0), whereas hypoalbuminaemia (<35 g/L) was present in 13.9% of patients. The prevalence of hypoalbuminaemia was significantly higher in patients with great complexity ACHD (18.2%) compared with patients with moderate (11.3%) or simple ACHD lesions (12.1%, p<0.001). During a median follow-up of 5.7 years (3.3-9.6), 327 (11.3%) patients died. On univariable Cox regression analysis, hypoalbuminaemia was a strong predictor of outcome (HR 3.37, 95% CI 2.67 to 4.25, p<0.0001). On multivariable Cox regression, after adjusting for age, sodium and creatinine concentration, liver dysfunction, functional class and disease complexity, hypoalbuminaemia remained a significant predictor of death. CONCLUSIONS: Hypoalbuminaemia is common in patients with ACHD and is associated with a threefold increased risk of risk of death. Hypoalbuminaemia, therefore, should be included in risk-stratification algorithms as it may assist management decisions and timing of interventions in the growing ACHD population.

Lung clearance index and high-resolution computed tomography scores in primary ciliary dyskinesia.

RATIONALE: Lung clearance index (LCI) is a more sensitive measure of lung function than spirometry in cystic fibrosis (CF) and correlates well with abnormalities in high-resolution computed tomography (HRCT) scanning. We hypothesized LCI would be equally sensitive to lung disease in primary ciliary dyskinesia (PCD). OBJECTIVES: To test the relationships between LCI, spirometry, and HRCT in PCD and to compare them to the established relationships in CF. METHODS: Cross-sectional study of 127 patients with CF and 33 patients with PCD, all of whom had spirometry and LCI, of which a subset of 21 of each had HRCT performed. HRCT was scored for individual features and these features compared with physiological parameters. MEASUREMENTS AND MAIN RESULTS: Unlike in CF, and contrary to our hypothesis, there was no correlation between spirometry and LCI in PCD and no correlation between HRCT features and LCI or spirometry in PCD. CONCLUSIONS: We show for the first time that HRCT, spirometry, and LCI have different relationships in different airway diseases and that LCI does not appear to be a sensitive test of airway disease in advanced PCD. We hypothesize that this results from dissimilarities between the components of large and small airway disease in CF and PCD. These differences may in part lead to the different prognosis in these two neutrophilic airway diseases.

Changes in physiological, functional and structural markers of cystic fibrosis lung disease with treatment of a pulmonary exacerbation.

BACKGROUND: Clinical trials in cystic fibrosis (CF) have been hindered by the paucity of well characterised and clinically relevant outcome measures. AIM: To evaluate a range of conventional and novel biomarkers of CF lung disease in a multicentre setting as a contributing study in selecting outcome assays for a clinical trial of CFTR gene therapy. METHODS: A multicentre observational study of adult and paediatric patients with CF (>10 years) treated for a physician-defined exacerbation of CF pulmonary symptoms. Measurements were performed at commencement and immediately after a course of intravenous antibiotics. Disease activity was assessed using 46 assays across five key domains: symptoms, lung physiology, structural changes on CT, pulmonary and systemic inflammatory markers. RESULTS: Statistically significant improvements were seen in forced expiratory volume in 1 s (p<0.001, n=32), lung clearance index (p<0.01, n=32), symptoms (p<0.0001, n=37), CT scores for airway wall thickness (p<0.01, n=31), air trapping (p<0.01, n=30) and large mucus plugs (p=0.0001, n=31), serum C-reactive protein (p<0.0001, n=34), serum interleukin-6 (p<0.0001, n=33) and serum calprotectin (p<0.0001, n=31). DISCUSSION: We identify the key biomarkers of inflammation, imaging and physiology that alter alongside symptomatic improvement following treatment of an acute CF exacerbation. These data, in parallel with our study of biomarkers in patients with stable CF, provide important guidance in choosing optimal biomarkers for novel therapies. Further, they highlight that such acute therapy predominantly improves large airway parameters and systemic inflammation, but has less effect on airway inflammation.

Myocardial apelin production is reduced in humans with left ventricular systolic dysfunction.

BACKGROUND: Apelin is a novel endogenous peptide with inotropic and vasodilatory properties that is the ligand for the APJ receptor. Apelin and APJ are widely distributed in the vasculature of a number of organs and peripheral venous apelin is reduced in heart failure (HF). The location of apelin production in humans with and without HF was investigated. METHODS AND RESULTS: Plasma apelin and brain natriuretic peptide (BNP) concentrations in coronary sinus (CS), aorta (Ao), and renal vein (RV) of individuals with HF (n = 9) were compared to subjects with normal structural hearts (n = 8). In HF the concentration of CS apelin was reduced compared with controls (310 pg/mL [interquartile range 290-390] vs. 470 pg/mL [340-570], P < .035) but Ao apelin (330 pg/mL [275-375] vs. 340 pg/mL [230-455], P = .76) and RV apelin (290 pg/mL [280-360] vs. 370 pg/mL [273-410], P = .56) were unchanged. Plasma BNP was increased at all sampling sites in patients with HF as compared with controls. A step down from CS to Ao to RV in all subjects was observed. The step down in apelin from CS to Ao (470 pg/mL [310-595] vs. 320 pg/mL [225-482], P < .04) in control subjects was not apparent in patients with HF. CONCLUSIONS: These novel data show that apelin is produced in the human heart and that production is reduced in individuals with HF. In contrast to BNP, apelin production is not exclusive to the heart.

High-dose adenosine overcomes the attenuation of myocardial perfusion reserve caused by caffeine.

OBJECTIVES: We studied whether an increase in adenosine dose overcomes caffeine antagonism on adenosine-mediated coronary vasodilation. BACKGROUND: Caffeine is a competitive antagonist at the adenosine receptors, but it is unclear whether caffeine in coffee alters the actions of exogenous adenosine, and whether the antagonism can be surmounted by increasing the adenosine dose. METHODS: Myocardial perfusion scintigraphy (MPS) was used to assess adenosine-induced hyperemia in 30 patients before (baseline) and after coffee ingestion (caffeine). At baseline, patients received 140 microg/kg/min of adenosine combined with low-level exercise. For the caffeine study, 12 patients received 140 microg/kg/min of adenosine (standard) and 18 patients received 210 microg/kg/min (high dose) after caffeine intake (200 mg). Myocardial perfusion was assessed semiquantitatively and quantitatively, and perfusion defect was characterized according to the presence of reversibility. RESULTS: Caffeine reduced the magnitude of perfusion abnormality induced by standard adenosine as measured by the summed difference score (SDS) (12.0 +/- 4.4 at baseline vs. 4.1 +/- 2.1 after caffeine, p < 0.001) as well as defect size (18% [3% to 38%] vs. 8% [0% to 22%], p < 0.01), whereas it had no effect on the abnormalities caused by high-dose adenosine (SDS, 7.7 +/- 4.0 at baseline vs. 7.8 +/- 4.2 after caffeine, p = 0.7). There was good agreement between baseline and caffeine studies for segmental defect category (kappa = 0.72, 95% confidence interval: 0.65 to 0.79) in the high-dose group. An increase in adenosine after caffeine intake was well tolerated. CONCLUSIONS: Caffeine in coffee attenuates adenosine-induced coronary hyperemia and, consequently, the detection of perfusion abnormality by adenosine MPS. This can be overcome by increasing the adenosine dose without compromising test tolerability.