232 research outputs found
Ten years of ageing in the middle-aged does not increase input impedance or wave reflection : insights from the Asklepios study
Pulsatile Load Components, Resistive Load and Incident Heart Failure: The Multi-Ethnic Study of Atherosclerosis (MESA)
Late systolic central hypertension as a predictor of incident heart failure : the Multi-Ethnic Study of Atherosclerosis
Background: Experimental studies demonstrate that high aortic pressure in late systole relative to early systole causes greater myocardial remodeling and dysfunction, for any given absolute peak systolic pressure.
Methods and Results: We tested the hypothesis that late systolic hypertension, defined as the ratio of late (last one third of systole) to early (first two thirds of systole) pressure-time integrals (PTI) of the aortic pressure waveform, independently predicts incident heart failure (HF) in the general population. Aortic pressure waveforms were derived from a generalized transfer function applied to the radial pressure waveform recorded noninvasively from 6124 adults. The late/early systolic PTI ratio (L/ESPTI) was assessed as a predictor of incident HF during median 8.5 years of follow-up. The L/ESPTI was predictive of incident HF (hazard ratio per 1% increase= 1.22; 95% CI= 1.15 to 1.29; P58.38%) was more predictive of HF than the presence of hypertension. After adjustment for each other and various predictors of HF, the HR associated with hypertension was 1.39 (95% CI= 0.86 to 2.23; P=0.18), whereas the HR associated with a high L/E was 2.31 (95% CI=1.52 to 3.49; P<0.0001).
Conclusions: Independently of the absolute level of peak pressure, late systolic hypertension is strongly associated with incident HF in the general population
Aging is associated with an earlier arrival of reflected waves without a distal shift in reflection sites
Background-Despite pronounced increases in central pulse wave velocity (PWV) with aging, reflected wave transit time (RWTT), traditionally defined as the timing of the inflection point (T-INF) in the central pressure waveform, does not appreciably decrease, leading to the controversial proposition of a "distal-shift" of reflection sites. T-INF, however, is exceptionally prone to measurement error and is also affected by ejection pattern and not only by wave reflection. We assessed whether RWTT, assessed by advanced pressure-flow analysis, demonstrates the expected decline with aging. Methods and Results-We studied a sample of unselected adults without cardiovascular disease (n=48; median age 48 years) and a clinical population of older adults with suspected/established cardiovascular disease (n=164; 61 years). We measured central pressure and flow with carotid tonometry and phase-contrast MRI, respectively. We assessed RWTT using wave-separation analysis (RWTTWSA) and partially distributed tube-load (TL) modeling (RWTTTL). Consistent with previous reports, T-INF did not appreciably decrease with age despite pronounced increases in PWV in both populations. However, aging was associated with pronounced decreases in RWTTWSA (general population -15.0 ms/decade, P<0.001; clinical population -9.07 ms/decade, P=0.003) and RWTTTL (general -15.8 ms/decade, P<0.001; clinical -11.8 ms/decade, P<0.001). There was no evidence of an increased effective reflecting distance by either method. TINF was shown to reliably represent RWTT only under highly unrealistic assumptions about input impedance. Conclusions-RWTT declines with age in parallel with increased PWV, with earlier effects of wave reflections and without a distal shift in reflecting sites. These findings have important implications for our understanding of the role of wave reflections with aging
Pulsatile load components, resistive load and incident heart failure : the Multi-Ethnic Study of Atherosclerosis (MESA)
Background: Left ventricular (LV) afterload is composed of systemic vascular resistance (SVR) and components of pulsatile load, including total arterial compliance (TAC), and reflection magnitude (RM). RM, which affects the LV systolic loading sequence, has been shown to strongly predict HF. Effective arterial elastance (E-a) is a commonly used parameter initially proposed to be a lumped index of resistive and pulsatile afterload. We sought to assess how various LV afterload parameters predict heart failure (HF) risk and whether RM predicts HF independently from subclinical atherosclerosis. Methods: We studied 4345 MESA participants who underwent radial arterial tonometry and cardiac output (CO) measurements with the use of cardiac MRI. RM was computed as the ratio of the backward (P-b) to forward (P-f) waves. TAC was approximated as the ratio of stroke volume (SV) to central pulse pressure. SVR was computed as mean pressure/CO. E-a was computed as central end-systolic pressure/SV. Results: During 10.3 years of follow-up, 91 definite HF events occurred. SVR (P = .74), TAC (P = .81), and E-a (P = .81) were not predictive of HF risk. RM was associated with increased HF risk, even after adjustment for other parameters of arterial load, various confounders, and markers of subclinical atherosclerosis (standardized hazard ratio [HR] 1.49, 95% confidence interval [CI] 1.18-1.88; P = .001). Pb was also associated with an increased risk of HF after adjustment for P-f (standardized HR 1.43, 95% CI 1.17-1.75; P = .001). Conclusions: RM is an important independent predictor of HF risk, whereas TAC, SVR, and E-a are not. Our findings support the importance of the systolic LV loading sequence on HF risk, independently from subclinical atherosclerosis
Objective Snoring Time and Carotid Intima-Media Thickness in Non-Apneic Female Snorers
Controversy persists about whether snoring can affect atherosclerotic changes in adjacent vessels, independently of obstructive sleep apnea and other cardiovascular risk factors. This study examined the independent association between snoring and carotid artery intima-media thickness (IMT) in non-apneic snorers and non-snorers. We studied 180 non-apneic snorers and non-snorers participating in a full-night home-based sleep study. Snoring sound was measured objectively by a microphone. Based on snoring time across the night, participants were classified as non-snorers (snoring time: 0%), mild snorers (1-25%) and moderate to heavy snorers (≥25%). We measured IMT on both common carotid arteries. The three groups were matched by age, body mass index, cholesterol, blood pressure and glucose levels, using weights from generalized boosted-propensity score models. Mean carotid IMT increased with increased snoring time across the night in women: non-snorers (0.707 mm), mild (0.718 mm) and moderate to heavy snorers (0.774 mm), but not in men. Snoring during at least one-fourth of a night\u27s sleep is associated independently with subclinical changes in carotid IMT in women only
Isosorbide dinitrate, with or without hydralazine, does not reduce wave reflections, left ventricular hypertrophy, or myocardial fibrosis in patients with heart failure with preserved ejection fraction
Background-Wave reflections, which are increased in patients with heart failure with preserved ejection fraction, impair diastolic function and promote pathologic myocardial remodeling. Organic nitrates reduce wave reflections acutely, but whether this is sustained chronically or affected by hydralazine coadministration is unknown. Methods and Results-We randomized 44 patients with heart failure with preserved ejection fraction in a double-blinded fashion to isosorbide dinitrate (ISDN; n=13), ISDN+hydralazine (ISDN+hydral; n=15), or placebo (n=16) for 6months. The primary end point was the change in reflection magnitude (RM; assessed with arterial tonometry and Doppler echocardiography). Secondary end points included change in left ventricular mass and fibrosis, measured with cardiac magnetic resonance imaging, and the 6-minute walk distance. ISDN reduced aortic characteristic impedance (mean baseline=0.15 [95% CI, 0.14-0.17], 3 months=0.11 [95% CI, 0.10-0.13], 6 months=0.10 [95% CI, 0.08-0.12] mmHg/mL per second; P=0.003) and forward wave amplitude (P-f, mean baseline=54.8 [95% CI, 47.6-62.0], 3 months=42.2 [95% CI, 33.2-51.3]; 6 months=37.0 [95% CI, 27.2-46.8] mmHg, P=0.04), but had no effect on RM (P=0.64), left ventricular mass (P=0.33), or fibrosis (P=0.63). ISDN+hydral increased RM (mean baseline=0.39 [95% CI, 0.35-0.43]; 3 months=0.31 [95% CI, 0.25-0.36]; 6 months=0.44 [95% CI, 0.37-0.51], P=0.03), reduced 6-minute walk distance (mean baseline=343.3 [95% CI, 319.2-367.4]; 6 months=277.0 [95% CI, 242.7-311.4] meters, P=0.022), and increased native myocardial T1 (mean baseline=1016.2 [95% CI, 1002.7-1029.7]; 6 months=1054.5 [95% CI, 1036.5-1072.3], P=0.021). A high proportion of patients experienced adverse events with active therapy (ISDN=61.5%, ISDN+hydral=60.0%; placebo=12.5%; P=0.007). Conclusions-ISDN, with or without hydralazine, does not exert beneficial effects on RM, left ventricular remodeling, or submaximal exercise and is poorly tolerated. ISDN+hydral appears to have deleterious effects on RM, myocardial remodeling, and submaximal exercise. Our findings do not support the routine use of these vasodilators in patients with heart failure with preserved ejection fraction
Right ventricular outflow tract velocity time integral-to-pulmonary artery systolic pressure ratio: a non-invasive metric of pulmonary arterial compliance differs across the spectrum of pulmonary hypertension.
Pulmonary arterial compliance (PAC), invasively assessed by the ratio of stroke volume to pulmonary arterial (PA) pulse pressure, is a sensitive marker of right ventricular (RV)-PA coupling that differs across the spectrum of pulmonary hypertension (PH) and is predictive of outcomes. We assessed whether the echocardiographically derived ratio of RV outflow tract velocity time integral to PA systolic pressure (RVOT-VTI/PASP) (a) correlates with invasive PAC, (b) discriminates heart failure with preserved ejection-associated PH (HFpEF-PH) from pulmonary arterial hypertension (PAH), and (c) is associated with functional capacity. We performed a retrospective cohort study of patients with PAH (n = 70) and HFpEF-PH (n = 86), which was further dichotomized by diastolic pressure gradient (DPG) into isolated post-capillary PH (DPG \u3c 7 mmHg; Ipc-PH, n = 54), and combined post- and pre-capillary PH (DPG ≥ 7 mm Hg; Cpc-PH, n = 32). Of the 156 patients, 146 had measurable RVOT-VTI or PASP and were included in further analysis. RVOT-VTI/PASP correlated with invasive PAC overall (ρ = 0.61, P \u3c 0.001) and for the PAH (ρ = 0.38, P = 0.002) and HFpEF-PH (ρ = 0.63, P \u3c 0.001) groups individually. RVOT-VTI/PASP differed significantly across the PH spectrum (PAH: 0.13 [0.010-0.25] vs. Cpc-PH: 0.20 [0.12-0.25] vs. Ipc-PH: 0.35 [0.22-0.44]; P \u3c 0.001), distinguished HFpEF-PH from PAH (AUC = 0.72, 95% CI = 0.63-0.81) and Cpc-PH from Ipc-PH (AUC = 0.78, 95% CI = 0.68-0.88), and remained independently predictive of 6-min walk distance after multivariate analysis (standardized β-coefficient = 27.7, 95% CI = 9.2-46.3; P = 0.004). Echocardiographic RVOT-VTI/PASP is a novel non-invasive metric of PAC that differs across the spectrum of PH. It distinguishes the degree of pre-capillary disease within HFpEF-PH and is predictive of functional capacity
Peripheral Determinants of Oxygen Utilization in Heart Failure With Preserved Ejection Fraction
The aim of this study was to determine the arteriovenous oxygen content difference (ΔAVO2) in adult subjects with and without heart failure with preserved ejection fraction (HFpEF) during systemic and forearm exercise. Subjects with HFpEF had reduced ΔAVO2. Forearm diffusional conductance for oxygen, a lumped conductance parameter that incorporates all impediments to the movement of oxygen from red blood cells in skeletal muscle capillaries into the mitochondria within myocytes, was estimated. Forearm diffusional conductance for oxygen was not different among adults with HFpEF, those with hypertension, and healthy control subjects; therefore, diffusional conductance cannot explain the reduced forearm ΔAVO2. Instead, adiposity was strongly associated with ΔAVO2, suggesting an active role for adipose tissue in reducing exercise capacity in patients with HFpEF
Determination of Sarcocystis lamacanis microcysts in the cardiac muscle of alpacas (Vicugna pacos) and their correlation with troponin cTnI. A study performed in the high Andean region of southern Peru
The breeding of alpaca (Vicugna pacos) is one of the most important economic activities in the high Andean areas of Peru. The commercialization of products derived from alpaca represents more than 80% of the income of high-Andean families. However, the infestation of parasites such as Sarcocystis lamacanis in the alpacas causes economic losses that deteriorate the already diminished quality of life of the alpaca breeder. The search for biomarkers that allow the early detection of these parasites is one of the most critical challenges in Peru, a country with the largest population of alpacas worldwide. This work aimed to analyze and quantify the microcysts formed by the parasite and relate them to the troponin cTnI level in the blood serum. Troponins are proteins secreted when there is damage to the cardiac muscle. 60 blood and cardiac tissue samples were collected from Tisco and La Raya slaughterhouses, localities of Caylloma Province in Arequipa, and Chucuito District in Puno, both regions in southern Peru. The cardiac muscle samples were processed with the routine histology technique and stained with hematoxylin and eosin. In addition, serum samples were processed with the ELISA and immunochromatography methods for troponin cTnI. Results were 100% positive for the presence of Sarcocystis lamacanis microcysts in all cardiac muscle samples. The average microcyst quantification per field of 100x were 3.5 and 5.7 for the Tisco and La Raya samples. In addition, several microscopic lesions were observed in the cardiac muscles: microcyst infiltration between muscle fibers, basophilic microcysts with a thick outer membrane and bradyzoites inside, and tissue displacement. On the other hand, all serum blood samples were negative for troponin cTnI, with both methods, ELISA and immunochromatography. For results, we infer troponin cTnI do not can be used as a biomarker for heart damage caused by Sarcocystis lamacanis parasite in alpacas.Fil: Fernandez F., Fernando. Universidad Católica de Santa María; PerúFil: Gutiérrez A., Roxana. Universidad Católica de Santa María; PerúFil: Pacheco S., Víctor. Universidad Católica de Santa María; PerúFil: Chirinos T., José. Universidad Católica de Santa María; PerúFil: Lombardo, Daniel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Instituto de Investigacion y Tecnología en Reproducción Animal; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias. Cátedra de Histología y Embriologías; ArgentinaFil: Olivera, Luis V. M.. Universidad Nacional del Altiplano; PerúFil: Bernabe Ortiz, Julio Cesar. Universidad Católica de Santa María; PerúFil: López Casaperalta, Patricia. Universidad Católica de Santa María; Per
- …