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Aims
Vitamin D deficiency is prevalent in heart failure (HF), but its relevance in early stages of heart failure with preserved ejection fraction (HFpEF) is unknown. We tested the association of 25-hydroxyvitamin D [25(OH)D] serum levels with mortality, hospitalizations, cardiovascular risk factors, and echocardiographic parameters in patients with asymptomatic diastolic dysfunction (DD) or newly diagnosed HFpEF.
Methods and results
We measured 25(OH)D serum levels in outpatients with risk factors for DD or history of HF derived from the DIAST-CHF study. Participants were comprehensively phenotyped including physical examination, echocardiography, and 6 min walk test and were followed up to 5 years. Quality of life was evaluated by the Short Form 36 (SF-36) questionnaire. We included 787 patients with available 25(OH)D levels. Median 25(OH)D levels were 13.1 ng/mL, mean E/e′ medial was 13.2, and mean left ventricular ejection fraction was 59.1%. Only 9% (n = 73) showed a left ventricular ejection fraction <50%. Fifteen per cent (n = 119) of the recruited participants had symptomatic HFpEF. At baseline, participants with 25(OH)D levels in the lowest tertile (≤10.9 ng/L; n = 263) were older, more often symptomatic (oedema and fatigue, all P ≤ 0.002) and had worse cardiac [higher N-terminal pro-brain natriuretic peptide (NT-proBNP) and left atrial volume index, both P ≤ 0.023], renal (lower glomerular filtration rate, P = 0.012), metabolic (higher uric acid levels, P < 0.001), and functional (reduced exercise capacity, 6 min walk distance, and SF-36 physical functioning score, all P < 0.001) parameters. Increased NT-proBNP, uric acid, and left atrial volume index and decreased SF-36 physical functioning scores were independently associated with lower 25(OH)D levels. There was a higher risk for lower 25(OH)D levels in association with HF, DD, and atrial fibrillation (all P ≤ 0.004), which remained significant after adjusting for age. Lower 25(OH)D levels (per 10 ng/mL decrease) tended to be associated with higher 5 year mortality, P = 0.05, hazard ratio (HR) 1.55 [1.00; 2.42]. Furthermore, lower 25(OH)D levels (per 10 ng/mL decrease) were related to an increased rate of cardiovascular hospitalizations, P = 0.023, HR = 1.74 [1.08; 2.80], and remained significant after adjusting for age, P = 0.046, HR = 1.63 [1.01; 2.64], baseline NT-proBNP, P = 0.048, HR = 1.62 [1.01; 2.61], and other selected baseline characteristics and co-morbidities, P = 0.043, HR = 3.60 [1.04; 12.43].
Conclusions
Lower 25(OH)D levels were associated with reduced functional capacity in patients with DD or HFpEF and were significantly predictive for an increased rate of cardiovascular hospitalizations, also after adjusting for age, NT-proBNP, and selected baseline characteristics and co-morbidities.
Aims
The role of diastolic dysfunction (DD) in prognostic evaluation in heart failure (HF) patients with impaired systolic function remains unclear. We investigated the impact of echocardiography-defined DD on survival in HF patients with mid-range (HFmrEF, EF 41–49%) and reduced ejection fraction (HFrEF, EF < 40%).
Methods and results
A total of 2018 consecutive hospitalized HF patients were retrospectively included and divided in two groups based on baseline EF: HFmrEF group (n = 951, aged 69 ± 13 years, 74.2% male) and HFrEF group (n = 1067, aged 68 ± 13 years, 76.3% male). Clinical data were collected and analysed. All patients completed ≥1 year clinical follow-up. The primary endpoint was defined as all-cause death (including heart transplantation) and cardiovascular (CV)-related death. All-cause mortality (30.8% vs. 24.9%, P = 0.003) and CV mortality (19.1% vs. 13.5%, P = 0.001) were significantly higher in the HFrEF group than the HFmrEF group during follow-up [median 24 (13–36) months]. All-cause mortality increased in proportion to DD severity (mild, moderate, and severe) in either HFmrEF (17.1%, 25.4%, and 37.0%, P < 0.001) or HFrEF (18.9%, 30.3%, and 39.2%, P < 0.001) patients. The risk of all-cause mortality [hazard ratio (HR) = 1.347, P = 0.015] and CV mortality (HR = 1.508, P = 0.007) was significantly higher in HFrEF patients with severe DD compared with non-severe DD after adjustment for identified clinical and echocardiographic covariates. For HFmrEF patients, severe DD was independently associated with increased all-cause mortality (HR = 1.358, P = 0.046) but not with CV mortality (HR = 1.155, P = 0.469).
Conclusions
Echocardiography-defined severe DD is independently associated with increased all-cause mortality in patients with HFmrEF and HFrEF.
DD is a cardiac disturbance, which has gained increasing importance in recent years due to its important role in different cardiac disease and cardiomyopathies including ischemic cardiomyopathy, arterial hypertension and diabetic cardiomyopathy.
ECG-gated 18F-FDG PET is an imaging technique, that can distinguish between districts of myocardial viability and myocardial scars and further provides information of great interest on the efficacy of experimental approaches designed to improve the cardiac function and/or myocardial metabolism in experimental small animal models. However, ECG-gated 18F-FDG PET is a technique whose feasibility in the assessment of the LV diastolic function in small animals has not been a subject of study.
In this thesis, the ability of the ECG-gated 18F-FDG PET for the assessment of both the systolic and diastolic function in eight control rats and in seven ZDF rats, which are an experimental animal model mimicking T2DM conditions and diabetic related complications in humans including DCM, has been investigated The ECG-gated 18F-FDG PET imaging was performed under hyperinsulinemic-euglycemic clamping and the data were stored in list mode files and retrospectively reconstructed. The systolic and diastolic parameters were achieved from the time/volume and the time/filling curve calculated from the software HFV. Additionally, the influence of the number of gates per cardiac cycle on the LV volumes and function parameters has been studied.
Hyperinsulinemic-euglycemic clamp procedure and blood glucose measurement did confirm the development of a manifest diabetes in the ZDF rats at the timepoint of the experiments.
Regarding the systolic parameters, no significant difference could be detected between the ZDF and ZL rats. The values for the CO were similar in both groups, which demonstrates a similar LV systolic function in the ZDF and the ZL rats at the age of 13 weeks. Values for the systolic parameters are in good line with previous PET, MRI and cardiac catheterization-based studies in diabetic rats.
The main finding of this study was that by using in vivo ECG-gated 18F-FDG PET and the software HFV, reliable diastolic parameters could be calculated. Moreover, it was possible to detect the presence of a mild impaired diastolic filling in the ZDF rats in absence of any systolic alteration. This impaired diastolic function in an early stage of diabetes could also be detected by other investigators, who used echocardiography or cardiac catheterization. Therefore, this is the first study showing, that the assessment of the diastolic function in rats can be carried out by ECG-gated 18F-FDG PET imaging.
In conclusion, additionally to calculating LV volumes and LV EF, ECG-gated 18F-FDG PET can evaluate the diastolic function of healthy and diabetic rats and is able to detect a DD in ZDF rats.