Dose-dependent benefit of nitroglycerin on microcirculation of patients with severe heart failure

Microcirculatory abnormalities are frequently observed in patients with severe heart failure and correlate to worse outcomes. We tested the hypothesis that nitroglycerin dose-dependently improves perfusion in severe heart failure and that this could be monitored by measuring central-peripheral temperature gradient and with Sidestream Dark Field imaging of the sublingual mucosa. A dose-response study was performed in 17 patients with cardiogenic shock (n = 9) or end-stage chronic heart failure (n = 8) admitted to Erasmus University Medical Center. We did hemodynamic measurements at baseline and during increasing infusion rates of nitroglycerin (up to a maximum dose of 133 mu g min(-1)). As parameters of tissue perfusion, we measured central-peripheral temperature gradient (delta-T) and sublingual perfused capillary density (PCD). Nitroglycerin dose-dependently decreased mean arterial pressure (p < 0.001) and cardiac filling pressures (both central venous pressure (CVP) and pulmonary capillary wedge pressure: p < 0.001). It increased cardiac index (p = 0.01). Nitroglycerin decreased delta-T (p < 0.001) and increased sublingual PCD (p < 0.001). Significant changes in delta-T and PCD occurred earlier, i.e., at a lower doses of NTG, than changes in global hemodynamics. Macrohemodynamic and microcirculatory responses to nitroglycerin infusion were consistent in patients with either cardiogenic shock or end-stage chronic heart failure. Changes in microcirculatory parameters occurred independently of changes in cardiac index. Nitroglycerin dose-dependently increases tissue perfusion in patients with severe heart failure, as observed by a decrease in central-peripheral temperature gradient and an increase in sublingual perfused capillary density.