Intravenous iron for heart failure, iron deficiency definitions, and clinical response: the IRONMAN trial.

BACKGROUND AND AIMS: What is the relationship between blood tests for iron deficiency, including anaemia, and the response to intravenous iron in patients with heart failure? METHODS: In the IRONMAN trial, 1137 patients with heart failure, ejection fraction ≤ 45%, and either serum ferritin < 100 µg/L or transferrin saturation (TSAT) < 20% were randomized to intravenous ferric derisomaltose (FDI) or usual care. Relationships were investigated between baseline anaemia severity, ferritin and TSAT, to changes in haemoglobin from baseline to 4 months, Minnesota Living with Heart Failure (MLwHF) score and 6-minute walk distance achieved at 4 months, and clinical events, including heart failure hospitalization (recurrent) or cardiovascular death. RESULTS: The rise in haemoglobin after administering FDI, adjusted for usual care, was greater for lower baseline TSAT (Pinteraction < .0001) and ferritin (Pinteraction = .028) and more severe anaemia (Pinteraction = .014). MLwHF scores at 4 months were somewhat lower (better) with FDI for more anaemic patients (overall Pinteraction = .14; physical Pinteraction = .085; emotional Pinteraction = .043) but were not related to baseline TSAT or ferritin. Blood tests did not predict difference in achieved walking distance for those randomized to FDI compared to control. The absence of anaemia or a TSAT ≥ 20% was associated with lower event rates and little evidence of benefit from FDI. More severe anaemia or TSAT < 20%, especially when ferritin was ≥100 µg/L, was associated with higher event rates and greater absolute reductions in events with FDI, albeit not statistically significant. CONCLUSIONS: This hypothesis-generating analysis suggests that anaemia or TSAT < 20% with ferritin > 100 µg/L might identify patients with heart failure who obtain greater benefit from intravenous iron. This interpretation requires confirmation.

Effect of Empagliflozin on Left Ventricular Volumes in Patients With Type 2 Diabetes, or Prediabetes, and Heart Failure With Reduced Ejection Fraction (SUGAR-DM-HF).

BACKGROUND: Sodium-glucose cotransporter 2 inhibitors reduce the risk of heart failure hospitalization and cardiovascular death in patients with heart failure and reduced ejection fraction (HFrEF). However, their effects on cardiac structure and function in HFrEF are uncertain. METHODS: We designed a multicenter, randomized, double-blind, placebo-controlled trial (the SUGAR-DM-HF trial [Studies of Empagliflozin and Its Cardiovascular, Renal and Metabolic Effects in Patients With Diabetes Mellitus, or Prediabetes, and Heart Failure]) to investigate the cardiac effects of empagliflozin in patients in New York Heart Association functional class II to IV with a left ventricular (LV) ejection fraction ≤40% and type 2 diabetes or prediabetes. Patients were randomly assigned 1:1 to empagliflozin 10 mg once daily or placebo, stratified by age (<65 and ≥65 years) and glycemic status (diabetes or prediabetes). The coprimary outcomes were change from baseline to 36 weeks in LV end-systolic volume indexed to body surface area and LV global longitudinal strain both measured using cardiovascular magnetic resonance. Secondary efficacy outcomes included other cardiovascular magnetic resonance measures (LV end-diastolic volume index, LV ejection fraction), diuretic intensification, symptoms (Kansas City Cardiomyopathy Questionnaire Total Symptom Score, 6-minute walk distance, B-lines on lung ultrasound, and biomarkers (including N-terminal pro-B-type natriuretic peptide). RESULTS: From April 2018 to August 2019, 105 patients were randomly assigned: mean age 68.7 (SD, 11.1) years, 77 (73.3%) male, 82 (78.1%) diabetes and 23 (21.9%) prediabetes, mean LV ejection fraction 32.5% (9.8%), and 81 (77.1%) New York Heart Association II and 24 (22.9%) New York Heart Association III. Patients received standard treatment for HFrEF. In comparison with placebo, empagliflozin reduced LV end-systolic volume index by 6.0 (95% CI, -10.8 to -1.2) mL/m2 (P=0.015). There was no difference in LV global longitudinal strain. Empagliflozin reduced LV end-diastolic volume index by 8.2 (95% CI, -13.7 to -2.6) mL/m2 (P=0.0042) and reduced N-terminal pro-B-type natriuretic peptide by 28% (2%-47%), P=0.038. There were no between-group differences in other cardiovascular magnetic resonance measures, diuretic intensification, Kansas City Cardiomyopathy Questionnaire Total Symptom Score, 6-minute walk distance, or B-lines. CONCLUSIONS: The sodium-glucose cotransporter 2 inhibitor empagliflozin reduced LV volumes in patients with HFrEF and type 2 diabetes or prediabetes. Favorable reverse LV remodeling may be a mechanism by which sodium-glucose cotransporter 2 inhibitors reduce heart failure hospitalization and mortality in HFrEF. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT03485092.

The relative importance of frailty, physical and cardiovascular function as exercise-modifiable predictors of falls in haemodialysis patients: a prospective cohort study.

BACKGROUND: Stage 5 chronic kidney disease (CKD-5) patients on haemodialysis (HD) are at high risk of accidental falls. Previous research has shown that frailty is one of the primary contributors to the increased risk of falling in this clinical population. However, HD patients often present with abnormalities of cardiovascular function such as baroreflex impairment and orthostatic dysregulation of blood pressure (BP) which may also be implicated in the aetiology of falling. Therefore, we aimed to explore the relative importance of frailty and cardiovascular function as potential exercise-modifiable predictors of falls in these patients. METHODS: Ninety-three prevalent CKD-5 patients on HD from three Renal Units were recruited for this prospective cohort study, which was conducted between October 2015 and August 2018. At baseline, frailty status was assessed using the Fried's frailty phenotype, while physical function was evaluated through timed up and go (TUG), five repetitions chair sit-to-stand (CSTS-5), objectively measured physical activity, and maximal voluntary isometric strength. Baroreflex and haemodynamic function at rest and in response to a 60° head-up tilt test (HUT-60°) were also assessed by means of the Task Force Monitor. The number of falls experienced was recorded once a month during 12 months of follow-up. RESULTS: In univariate negative binomial regression analysis, frailty (RR: 4.10, 95%CI: 1.60-10.51, p = 0.003) and other physical function determinants were associated with a higher number of falls. In multivariate analysis however, only worse baroreflex function (RR: 0.96, 95%CI: 0.94-0.99, p = 0.004), and orthostatic decrements of BP to HUT-60° (RR: 0.93, 95%CI: 0.87-0.99, p = 0.033) remained significantly associated with a greater number of falls. Eighty falls were recorded during the study period and the majority of them (41.3%) were precipitated by dizziness symptoms, as reported by participants. CONCLUSIONS: This prospective study indicates that cardiovascular mechanisms implicated in the short-term regulation of BP showed a greater relative importance than frailty in predicting falls in CKD-5 patients on HD. A high number of falls appeared to be mediated by a degree of cardiovascular dysregulation, as evidenced by the predominance of self-reported dizziness symptoms. TRIAL REGISTRATION: ClinicalTrials.gov (trial registration ID: NCT02392299; date of registration: March 18, 2015).

Proportional pulse pressure relates to cardiac index in stabilized acute heart failure patients.

AIMS: In chronic heart failure, proportional pulse pressure (PPP) is suggested as an estimate of cardiac index (CI). The association between CI and PPP in acute heart failure (AHF) has not been described. METHODS: This was examined using hemodynamic measurements (from a trial using serelaxin) in 63 stabilized AHF patients. RESULTS: Mean (SD) age was 68 (11), 74% male, mean (SD) ejection fraction (EF) was 33.4% (13.7), mean (SD) CI (L/min/m2) was 2.3 (0.6). CI correlated with PPP (Pearson R = 0.42; p < 0.0001) based on a linear mixed-effects model analysis of 171 pairs of measurements from 47 patients (out of 63) where CI and PPP were measured within 3 min of each other during. Serelaxin treatment did not modify the established correlation between CI and PPP. Time-weighted average CI correlated with time-weighted average PPP (Spearman Rank R = 0.35; p = 0.0051) over the -4 h to 24 h time interval. In a multivariable regression analysis, low PPP was an independent predictor of low CI (p < 0.0001). CONCLUSIONS: In patients with AHF after initial clinical stabilization, both baseline and post-baseline CI measurements are positively related to PPP. This was the most closely related non-invasive blood pressure variable to CI.

How is dilated cardiomyopathy investigated in Scotland? A contemporary survey.

BACKGROUND AND AIMS: Dilated cardiomyopathy (DCM) is a common cause of heart failure. The underlying aetiology remains poorly characterised, with ca. 50% labelled 'idiopathic'. We assessed the extent to which the aetiology of DCM is investigated in Scotland, in comparison to European Society of Cardiology (ESC) recommendations. METHODS AND RESULTS: Questionnaires regarding the use of coronary angiography, use and availability of cardiac magnetic resonance imaging (CMR) and blood/urine panels to investigate the causes of DCM were sent to the heart failure lead in each of the 23 hospitals across Scotland with an established cardiology department; responses were obtained from 21/23 (91.3%). ESC guidelines regarding coronary angiography were adopted in only 8/21 (38.1%). Only 7/21 (33.3%) had easy access to CMR although 14/21 (66.7%) felt it would be a useful test in DCM. The ESC-recommended blood profile was checked routinely in 7/21 (33.3%). Additional blood tests, many of which not currently recommended, were performed in selected centres. CONCLUSIONS: DCM patients in Scotland are in general unlikely to undergo current ESC-recommended investigation into the underlying aetiology. There is a need for prospective studies to determine the success rate and influence on management and outcome of such multifaceted approaches to investigating the cause of DCM.

Interleukin-21--a biomarker of importance in predicting myocardial function following acute infarction?

INTRODUCTION: Following acute myocardial infarction (AMI), the acute inflammatory response contributes to wound healing but also to progressive myocardial injury. Interleukin-21 (IL-21) plays a key role in immunoregulation; whether IL-21 is associated with left ventricular (LV) remodelling after AMI is unknown. METHODS: Plasma IL-21 concentrations were measured in 100 patients (age 58.9 ± 12.0 years, 77% male) admitted with AMI and LV dysfunction, at baseline (mean 46 h) and again at 24 weeks; cardiac magnetic resonance and measurement of B-type natriuretic peptide, monocyte chemoattractant protein-1, matrix metalloproteinase (MMP)-2, -3, -9, and tissue inhibitor of metalloproteinase (TIMP)-1, -2, -4 occurred at both time-points. Remodelling was defined as change in LV end-systolic volume index (ΔLVESVI). RESULTS: Plasma IL-21 concentration was unchanged over time (48.1 [SD 35.4]pg/mL at baseline vs. 48.8 [61.3]pg/mL at 24 weeks, p=0.92). Baseline IL-21 correlated significantly with ΔLVESVI (r=0.30, p=0.005) and change in LV end-diastolic volume index (r=0.33, p=0.003). On multivariate analysis, plasma IL-21 was an independent predictor of remodelling. IL-21 was also significantly associated with higher TIMP-4 concentrations and lower MMP-9 concentrations at baseline. CONCLUSIONS: IL-21 predicts adverse remodelling following AMI in patients with LV dysfunction. Whether it plays a direct pathophysiological role in remodelling merits further study.

Adult-onset recurrent Kawasaki disease: an unusual cause of fever of unknown origin.

We present the case of a 20-year-old man with a background of transposition of the great arteries presenting with fever of unknown origin, who developed a shock like syndrome with respiratory failure necessitating intubation. After extensive investigation, a diagnosis of adult-onset Kawasaki disease was made, and he was successfully treated with IVIg and corticosteroids. We present the clinical findings clinicians should be aware of, and review the literature on managing this rare presentation in adult, highlighting the importance of early diagnosis in improving outcomes. Both children and adults with Kawasaki disease require long-term follow-up, as they remain at increased risk of both coronary artery aneurysms and early acute coronary syndrome.

Monocyte chemoattractant protein-1: a dichotomous role in cardiac remodeling following acute myocardial infarction in man?

INTRODUCTION: Monocyte chemoattractant protein-1 (MCP-1) is elevated after acute myocardial infarction (AMI), and potentiates left ventricular (LV) remodeling in murine models of AMI. We examined the relationships between serum MCP-1, change in LV function and biomarkers related to remodeling in a cohort of AMI patients. METHODS: Serum MCP-1 concentrations were measured in 100 patients (age 58.9+/-12.0 years, 77% male) admitted with AMI and LV dysfunction, at baseline (mean 46 h), 12 and 24 weeks; cardiac magnetic resonance imaging and measurement of matrix metalloproteinase-2 (MMP-2), MMP-3 and MMP-9 occurred at each time-point. RESULTS: MCP-1 increased significantly from 697 [483, 997]pg/mL at baseline to 878 [678, 1130]pg/mL at 24 weeks (p<0.001). MMP-3 concentration increased while MMP-9 decreased significantly over time; MMP-2 concentration did not change significantly. BASELINE MCP-1 correlated with change in (Delta) LV end-systolic volume index (DeltaLVESVI; r= -0.48, p=0.01) and with DeltaLV ejection fraction (DeltaLVEF; r=0.50, p=0.02). However, DeltaMCP-1 correlated positively with DeltaLVESVI (r=0.40, p=0.006) and negatively with DeltaLVEF (r= -0.36, p=0.004). MCP-1 had no relationship with any MMP. CONCLUSIONS: MCP-1 may have a dichotomous role following AMI, aiding early infarct healing but potentiating later remodeling, which merits further study before any therapeutic trials of MCP-1 modulation in humans.

Comparison of serial measurements of infarct size and left ventricular ejection fraction by contrast-enhanced cardiac magnetic resonance imaging and electrocardiographic QRS scoring in reperfused anterior ST-elevation myocardial infarction.

BACKGROUND: Left ventricular ejection fraction (LVEF) is a powerful prognostic marker after acute myocardial infarction and is dependent on infarct magnitude. Contrast-enhanced cardiac magnetic resonance (ceCMR) represents the current criterion standard means of LVEF and infarct size measurement. Infarct size and LVEF can be estimated from the 12-lead electrocardiogram (ECG) using the Selvester QRS score. We examined for the first time the relationship between serial measures of LVEF and infarct size by ceCMR and ECG in patients with reperfused anterior ST-elevation myocardial infarction (STEMI) and depressed LVEF. METHODS: Thirty-four patients (mean +/- SD age, 59 +/- 11.8 years; 70.6% male) underwent ceCMR and simultaneous ECG at mean 93 hours after admission and at 12 and 24 weeks. The QRS score was calculated on each ECG, from which infarct size and LVEF were estimated and compared with the equivalent ceCMR measurements. RESULTS: Infarct size on ceCMR was higher than that by QRS score at each time-point (P < .001) with modest correlation (r = 0.56-0.78, P < .001). Left ventricular ejection fraction was consistently significantly higher on CMR than on ECG, with weak correlation (r = 0.37-0.51, P < .05). We derived a novel equation relating QRS score to CMR-measured LVEF in the subacute phase of infarction: LVEF = 61 - (1.7 x QRS score) (%). CONCLUSIONS: In patients with reperfused anterior ST-elevation myocardial infarction and depressed LVEF, ceCMR is moderately correlated with the QRS in the serial measurement of infarct size and LVEF. Infarct size (measured by ceCMR) and LVEF are consistently higher than those calculated on the QRS score in the acute and subacute phases of infarction.

Chest pain with less than 20% change in high sensitivity troponin T - a low risk cohort?

Background: Patients with chest pain are risk-stratified using serial high-sensitivity troponin (T) assays (hsTnT). Those with change in (Δ)hsTnT <20% are often categorised as low-risk and are less likely to be managed as acute coronary syndromes (ACS). We sought to characterise such a population of 'low-risk' chest pain presenters.Methods: We performed a retrospective cohort analysis of sequential patients admitted to our centre over a 1-year period with chest pain, absence of ST-elevation, with elevated hsTnT concentrations, and compared demographic, clinical and outcome data according to ΔhsTnT.Results: Three hundred and eleven patients were subdivided by ΔhsTnT [<20% (n = 80), 20-100% (n = 78), >100% (n = 153)]. Baseline demographic data were well-matched across the three subgroups; atrial fibrillation was more common in the two lower magnitude ΔhsTnT groups. Obstructive coronary artery disease (CAD) - while less common in those with ΔhsTnT <20% (66.2%) compared to the 20-100% (73.1%) and >100% (75.9%) groups (p = 0.03) - remained high in this lower risk group, and indeed revascularisation occurred in >60% of patients, equally frequently in all three groups. Using absolute ΔhsTnT ≥9ng/L within the ΔhsTnT <20% group provided incremental value in ruling in ACS, with a positive predictive value of 74.1%. ΔhsTnT was a univariate but not a multivariate predictor of obstructive CAD.Conclusions: Obstructive CAD and need for revascularisation are frequent in chest pain presenters with ΔhsTnT <20%. The increasing focus on hsTnT algorithms to exclude ACS and promote early discharge without adequate clinical risk stratification modelling risks misdiagnosis of patients presenting with acute myocardial ischaemia with a low-level hsTnT rise.

Comparative Significance of Invasive Measures of Microvascular Injury in Acute Myocardial Infarction.

BACKGROUND: The resistive reserve ratio (RRR) expresses the ratio between basal and hyperemic microvascular resistance. RRR measures the vasodilatory capacity of the microcirculation. We compared RRR, index of microcirculatory resistance (IMR), and coronary flow reserve (CFR) for predicting microvascular obstruction (MVO), myocardial hemorrhage, infarct size, and clinical outcomes, after ST-segment-elevation myocardial infarction. METHODS: In the T-TIME trial (Trial of Low-Dose Adjunctive Alteplase During Primary PCI), 440 patients with acute ST-segment-elevation myocardial infarction from 11 UK hospitals were prospectively enrolled. In a subset of 144 patients, IMR, CFR, and RRR were measured post-primary percutaneous coronary intervention. MVO extent (% left ventricular mass) was determined by cardiovascular magnetic resonance imaging at 2 to 7 days. Infarct size was determined at 3 months. One-year major adverse cardiac events, heart failure hospitalizations, and all-cause death/heart failure hospitalizations were assessed. RESULTS: In these 144 patients (mean age, 59±11 years, 80% male), median IMR was 29.5 (interquartile range: 17.0-55.0), CFR was 1.4 (1.1-2.0), and RRR was 1.7 (1.3-2.3). MVO occurred in 41% of patients. IMR>40 was multivariably associated with more MVO (coefficient, 0.53 [95% CI, 0.05-1.02]; P=0.031), myocardial hemorrhage presence (odds ratio [OR], 3.20 [95% CI, 1.25-8.24]; P=0.016), and infarct size (coefficient, 5.05 [95% CI, 0.84-9.26]; P=0.019), independently of CFR≤2.0, RRR≤1.7, myocardial perfusion grade≤1, and Thrombolysis in Myocardial Infarction frame count. RRR was multivariably associated with MVO extent (coefficient, -0.60 [95% CI, -0.97 to -0.23]; P=0.002), myocardial hemorrhage presence (OR, 0.34 [95% CI, 0.15-0.75]; P=0.008), and infarct size (coefficient, -3.41 [95% CI, -6.76 to -0.06]; P=0.046). IMR>40 was associated with heart failure hospitalization (OR, 5.34 [95% CI, 1.80-15.81] P=0.002), major adverse cardiac events (OR, 4.46 [95% CI, 1.70-11.70] P=0.002), and all-cause death/ heart failure hospitalization (OR, 4.08 [95% CI, 1.55-10.79] P=0.005). RRR was associated with heart failure hospitalization (OR, 0.44 [95% CI, 0.19-0.99] P=0.047). CFR was not associated with infarct characteristics or clinical outcomes. CONCLUSIONS: In acute ST-segment-elevationl infarction, IMR and RRR, but not CFR, were associated with MVO, myocardial hemorrhage, infarct size, and clinical outcomes. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02257294.

Left ventricular remodeling after acute myocardial infarction: does eplerenone have an effect?

AIMS: Aldosterone antagonism reduces cardiovascular morbidity and mortality in patients with left ventricular (LV) systolic dysfunction and heart failure or diabetes after acute myocardial infarction (AMI). The mechanism of this effect is unclear. We performed a contrast-enhanced cardiac magnetic resonance study to assess the effects of eplerenone on LV remodeling after AMI. METHODS: One hundred patients (mean age, 58.9 +/- 12 years; 77% male) with LV systolic dysfunction but without heart failure or diabetes were randomized to 24 weeks' double-blind treatment with eplerenone or placebo started 1 to 14 days after AMI. Contrast-enhanced cardiac magnetic resonance was performed, and plasma concentrations of matrix metalloproteinase-2 (MMP-2) and MMP-9 were measured before randomization and at 12 and 24 weeks. RESULTS: Baseline LV ejection fraction was, by chance, significantly higher in eplerenone than in placebo-treated patients. Eplerenone had no effect on the primary end point (change in LV end-systolic volume index); after covariate adjustment, the primary end point fell by 6.1 +/- 2.7 mL/m2 with eplerenone compared to placebo (P = .027), and LV end-diastolic volume index fell by 7.5 +/- 3.4 mL/m2 (P = .031); eplerenone did not significantly influence LV ejection fraction. Eplerenone, after covariate adjustment, significantly decreased MMP-2 and increased MMP-9 over 24 weeks relative to placebo. CONCLUSIONS: In a population of patients with AMI with high uptake of contemporary antiremodeling therapy, eplerenone provides modest incremental protection against LV remodeling, only after covariate adjustment.

Plasma apelin concentration is depressed following acute myocardial infarction in man.

AIMS: Apelin, a novel peptide with a putative role in cardiovascular homeostasis, has gained interest as an endogenous inotrope, but has yet to be described following acute myocardial infarction (AMI) in man. We aimed to characterize plasma apelin concentrations following AMI and to examine its relationship with clinical and prognostic biomarkers. METHODS AND RESULTS: Plasma concentrations of apelin, N-terminal probrain natriuretic peptide (NT-proBNP), norepinephrine, and arginine vasopressin were measured in 100 patients [mean age 58.9 +/- 12 (SD) years, 77% male] admitted with AMI, with echocardiographic left ventricular (LV) ejection fraction <40%, at mean 46 h after admission and at 24 weeks. Cardiac magnetic resonance imaging was performed pre-discharge and at 24 weeks. Thirty-eight subjects with no cardiac history acted as controls. Apelin concentration was reduced early after AMI (0.54 +/- 0.25 vs. 3.22 +/- 3.01 ng/mL, P <0.001) and remained low at 24 weeks, although it did increase significantly from baseline to 0.62 +/- 0.36 ng/mL, P = 0.030. Apelin had no relationship with any parameter of LV function over time. A relationship was found between baseline apelin and norepinephrine (r = 0.26, P = 0.008). Both NT-proBNP and norepinephrine correlated with adverse ventricular function after AMI. CONCLUSION: Plasma apelin concentration is reduced early after AMI, increases significantly over time, but remains depressed at 24 weeks.

Cardiac and extracardiac abnormalities detected by cardiac magnetic resonance in a post-myocardial infarction cohort.

OBJECTIVES: All patients should undergo formal assessment of ventricular function following acute myocardial infarction (AMI). Cardiac magnetic resonance (CMR) is not widely used as a test before discharge in AMI patients. This study sought to determine the impact of contrast-enhanced CMR (ceCMR) scanning before discharge in addition to standard transthoracic echocardiography (TTE) on patient care following AMI. METHODS: 100 patients admitted with AMI, all of whom had a left ventricular ejection fraction (LVEF) <40% on TTE, underwent ceCMR imaging before discharge. Abnormalities of clinical relevance detected on ceCMR, which influenced patient management, are reported. RESULTS: Each patient (77% male, mean age 58.9 years, SD 12) underwent TTE and ceCMR at a mean 1.4 (range 0.8-3.2) and 4.2 days (range 2-11), respectively, following admission. ceCMR significantly influenced the management of 24/100 (24%) of the patient cohort, through detection of LV thrombus, right ventricular infarction, intracardiac neoplasia, and a variety of intrathoracic and intra-abdominal pathology. There were no issues regarding safety in this high-risk group of patients. CONCLUSION: In a cohort of AMI patients with reduced LVEF, ceCMR scanning before discharge improved the management of 24% of the cohort. ceCMR is a useful and safe adjunct to standard care after AMI.

Baroreflex function, haemodynamic responses to an orthostatic challenge, and falls in haemodialysis patients.

BACKGROUND: Stage 5 chronic kidney disease patients on haemodialysis (HD) often present with dizziness and pre-syncopal events as a result of the combined effect of HD therapy and cardiovascular disease. The dysregulation of blood pressure (BP) during orthostasis may be implicated in the aetiology of falls in these patients. Therefore, we explored the relationship between baroreflex function, the haemodynamic responses to a passive orthostatic challenge, and falls in HD patients. METHODS: Seventy-six HD patients were enrolled in this cross-sectional study. Participants were classified as "fallers" and "non-fallers" and completed a passive head up tilting to 60o (HUT-60°) test on an automated tilt table. ECG signals, continuous and oscillometric BP measurements and impedance cardiography were recorded. The following variables were derived from these measurements: heart rate (HR) stroke volume (SV), cardiac output (CO), total peripheral resistance (TPR), number of baroreceptor events, and baroreceptor effectiveness index (BEI). RESULTS: The forty-four participants who were classified as fallers (57.9%) had a lower number of baroreceptor events (6.5±8.5 vs 14±16.7, p = .027) and BEI (20.8±24.2% vs 33.4±23.3%, p = .025). In addition, fallers experienced a significantly larger drop in systolic (-6.4±10.9 vs -0.4±7.7 mmHg, p = .011) and diastolic (-2.7±7.3 vs 1.8±6 mmHg, p = .027) oscillometric BP from supine to HUT-60° compared with non-fallers. None of the variables taken for the analysis were significantly associated with falls in multivariate logistic regression analysis. CONCLUSIONS: This cross-sectional comparison indicates that, at rest, HD patients with a positive history of falls present with a lower count of baroreceptor sequences and BEI. Short-term BP regulation warrants further investigation as BP drops during a passive orthostatic challenge may be implicated in the aetiology of falls in HD.