RESUMO
Hemodialysis patients have conditions that increase cardiac output (CO), including arteriovenous fistula, fluid retention, vasodilator use, and anemia. We sought to determine the relationships between these factors and CO and to evaluate the effects of the high-output states on ventricular morphology, function, and myocardial energetics in hemodialysis patients, using noninvasive load-insensitive indices. Cardiovascular function was assessed in hemodialysis patients with high output [ejection fraction ≥ 50%, cardiac index (CI) > 3.5 L/min/m2, n = 30], those with normal output (CI < 3.0 L/min/m2, n = 161), and control subjects without hemodialysis (n = 155). As compared to control subjects and hemodialysis patients with normal CI, patients with elevated CI were anemic and displayed decreased systemic vascular resistance index (SVRI), excessive left ventricular (LV) contractility, larger LV volume, and tachycardia. Lower hemoglobin levels were correlated with decreased SVRI, excessive LV contractility, and higher heart rate, while estimated plasma volume and interdialytic weight gain were associated with larger LV volume, thus increasing CO. High output patients displayed markedly increased pressure-volume area (PVA) and PVA/stroke volume ratio, which were correlated directly with CO. The use of combination vasodilator therapy (angiotensin-converting enzyme inhibitor/angiotensin-receptor blocker and calcium channel blocker) was not associated with high-output states. In conclusion, anemia and fluid retention are correlated with increased CO in hemodialysis patients. The high-output state is also associated with excessive myocardial work and energy cost.
Assuntos
Débito Cardíaco Elevado/fisiopatologia , Débito Cardíaco , Metabolismo Energético , Nefropatias/terapia , Contração Miocárdica , Miocárdio/metabolismo , Diálise Renal , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular Esquerda , Idoso , Anemia/etiologia , Anemia/fisiopatologia , Derivação Arteriovenosa Cirúrgica/efeitos adversos , Débito Cardíaco Elevado/diagnóstico por imagem , Débito Cardíaco Elevado/etiologia , Débito Cardíaco Elevado/metabolismo , Estudos Transversais , Ecocardiografia , Feminino , Deslocamentos de Líquidos Corporais , Insuficiência Cardíaca/etiologia , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/fisiopatologia , Frequência Cardíaca , Humanos , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/metabolismo , Hipertrofia Ventricular Esquerda/fisiopatologia , Japão , Nefropatias/complicações , Nefropatias/diagnóstico por imagem , Nefropatias/fisiopatologia , Masculino , Pessoa de Meia-Idade , Consumo de Oxigênio , Diálise Renal/efeitos adversos , Estudos Retrospectivos , Fatores de Risco , Vasodilatadores/uso terapêutico , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/metabolismo , Equilíbrio Hidroeletrolítico , Desequilíbrio Hidroeletrolítico/etiologia , Desequilíbrio Hidroeletrolítico/fisiopatologiaRESUMO
Plasma immunoreactive endothelin (irET) concentration and renal glomerular ET receptors were investigated in rats with chronic high-output heart failure. Plasma irET was higher (0.67 +/- 0.03 fmol/ml vs. 0.52 +/- 0.04 fmol/ml) and the density of glomerular ET receptors lower (Bmax: 420 +/- 20 fmol/mg protein vs. 510 +/- 12 fmol/mg protein) in rats with heart failure than in controls. Our results indicate that circulating ET levels are responsive to changes in cardiovascular hemodynamics and suggest a potential role for ET as a vasoactive regulatory peptide during heart failure.
