7 research outputs found
Effect of organic and inorganic nitrates on cerebrovascular pulsatile power transmission in patients with heart failure and preserved ejection fraction
Objective: Increased penetration of pulsatile power to the brain has been implicated in the pathogenesis of age-related cognitive dysfunction and dementia, a common comorbidity in patients with heart failure and preserved ejection fraction (HFpEF). However, there is a lack of knowledge on the effects of organic and inorganic nitrates administration in this population on the power carried by pressure and flow waves traveling through the proximal aorta and penetrating the carotid artery into the brain microvasculature. Approach: We assessed aortic and carotid hemodynamics non-invasively in two sub-studies: (1) at baseline and after administration of 0.4 mg of sublingual nitroglycerine (an organic nitrate; n = 26); and (2) in a randomized controlled trial of placebo (PB) versus inorganic nitrate administration (beetroot-juice (BR), 12.9 mmol NO3; n = 16). Main results: Wave and hydraulic power analysis demonstrated that NTG increased total hydraulic power (from 5.68% at baseline to 8.62%, P = 0.001) and energy penetration (from 8.69% to 11.63%; P = 0.01) from the aorta to the carotid, while inorganic nitrate administration did not induce significant changes in aortic and carotid wave power (power: 5.49% PB versus 6.25% BR, P = 0.49; energy: 8.89% PB versus 10.65% BR, P = 0.27). Significance: Organic nitrates, but not inorganic nitrates, increase the amount of hydraulic energy transmitted into the carotid artery in subjects with HFpEF. These findings may have implications for the adverse effect profiles of these agents (such as the differential incidence of headaches) and for the pulsatile hemodynamic stress of the brain microvasculature in this patient population
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
Isosorbide Dinitrate, With or Without Hydrazine, Does Not Reduce Wave Reflections, LV Hypertrophy or Fibrosis in HFpEF
Diarrea del viajero
La diarrea del viajero es una de las condiciones que con mayor frecuencia afecta a los viajeros de pa铆ses industrializados que visitan las zonas tropicales y subtropicales del planeta. El 20 a 50% de viajeros se van afectar por esta condici贸n, siendo en ocasiones tan severa como para afectar los planes del viajero en la quinta parte de pacientes. El cuadro se manifiesta por la aparici贸n de diarrea asociada a s铆ntomas ent茅ricos como dolor abdominal, nauseas, v贸mitos y en caso de diarrea inflamatoria fiebre y deposiciones con sangre. Entre los agentes etiol贸gicos bacterianos m谩s frecuentes est谩n Escherichia coli enterotoxig茅nica, Salmonella, Shigella, entre otros agentes, aunque en cerca de la mitad de los casos no se a铆sla un agente etiol贸gico. En caso de diarrea persistente debe descartarse par谩sitos y en zonas end茅micas debe realizarse las pruebas especiales para descartar infecci贸n por Cyclospora cayetanensis. En pacientes con diarrea del viajero est谩 indicado el manejo emp铆rico con antibi贸ticos, lo cual disminuye la duraci贸n de la enfermedad. En ausencia de fiebre o diarrea con sangre puede usarse loperamida. La prevenci贸n es importante en especialmente en pacientes de alto riesgo o en quienes sea importante que no se afecte el viaje
Diarrea del viajero
La diarrea del viajero es una de las condiciones que con mayor frecuencia afecta a los viajeros de pa铆ses industrializados que visitan las zonas tropicales y subtropicales del planeta. El 20 a 50% de viajeros se van afectar por esta condici贸n, siendo en ocasiones tan severa como para afectar los planes del viajero en la quinta parte de pacientes. El cuadro se manifiesta por la aparici贸n de diarrea asociada a s铆ntomas ent茅ricos como dolor abdominal, nauseas, v贸mitos y en caso de diarrea inflamatoria fiebre y deposiciones con sangre. Entre los agentes etiol贸gicos bacterianos m谩s frecuentes est谩n Escherichia coli enterotoxig茅nica, Salmonella, Shigella, entre otros agentes, aunque en cerca de la mitad de los casos no se a铆sla un agente etiol贸gico. En caso de diarrea persistente debe descartarse par谩sitos y en zonas end茅micas debe realizarse las pruebas especiales para descartar infecci贸n por Cyclospora cayetanensis. En pacientes con diarrea del viajero est谩 indicado el manejo emp铆rico con antibi贸ticos, lo cual disminuye la duraci贸n de la enfermedad. En ausencia de fiebre o diarrea con sangre puede usarse loperamida. La prevenci贸n es importante en especialmente en pacientes de alto riesgo o en quienes sea importante que no se afecte el viaje