A Comparative Study of Cerebral Microcirculation During Pulsatile and Nonpulsatile Selective Cerebral Perfusion

Abstract

Currently, nonpulsatile selective cerebral perfusion for cerebroprotection against thoracic aortic aneurysm is used in clinical settings. We performed synchrotron radiation microangiography to determine the effects on selective cerebral perfusion modulation by pulsatile flow. We established cerebral perfusion at normothermia and severe hypothermia in anesthetized rats, during which cerebral angiography was performed. NG-nitro-L-arginine-methyl ester hydrochloride (L-NAME) was administered to determine the effect of pulsatile flow with nitric oxide synthesis. In comparison with nonpulsatile flow, the relative diameters of small internal carotid artery were 132.11 ± 5.49% and 114.96 ± 4.60% during pulsatile flow at normothermia and severe hypothermia (p < 0.05). The angiographic scores, an indicator of vessel count, for nonpulsatile and pulsatile flow at normothermia were 0.198 ± 0.013 vs. 0.258 ± 0.010 (p < 0.001) and those at severe hypothermia were 0.158 ± 0.017 vs. 0.214 ± 0.015 (p < 0.01), respectively. In comparison with nonpulsatile flow, the relative internal carotid artery diameters during pulsatile flow with and without L-NAME were 98.50 ± 1.7% vs. 114.96 ± 4.6%, respectively, during severe hypothermia. These results show that pulsatile flow is effective in increasing blood vessel diameter, number of vessels, and perfusion distribution range in the rat model and that it was more effective at normothermia during nitric oxide production.

Effect of the Pulsatile Extracorporeal Membrane Oxygenation on Hemodynamic Energy and Systemic Microcirculation in a Piglet Model of Acute Cardiac Failure

“…Moreover, our results demonstrated that pulsatile ECMO produces methemoglobin levels within the normal range, compared with nonpulsatile ECMO. Nitric oxide secretion from the endothelium is stimulated by the mechanical shear stress of pulsatile flow acting on vessel endothelium (25). This indicates that pulsatile flow produces more nitric oxide than nonpulsatile flow (19)(20)(21)(22)(23)(24).…”

“…Nitric oxide secretion causes systemic vasodilation by diffusing into vascular smooth muscle cells (19,21). Nitric oxide secretion from the endothelium is stimulated by the mechanical shear stress of pulsatile flow acting on vessel endothelium (25). For this reason, pulsatile blood flow may reduce systemic vascular resistances and maintain better circulation in microvessels by increasing nitric oxide secretion.…”

CrossTalk proposal: Blood flow pulsatility in left ventricular assist device patients is essential to maintain normal brain physiology

“…; Inamori et al . ). Importantly, the authors also reported, ‘pulsatility resulted in a reduction in the prevalence of pathologic hyper‐dynamically perfused vessels’ (O'Neil et al .…”

“…In any case, it is important to consider cardiac output in relation to the local peripheral vasodilatation and vasoconstriction. Studies examining the effects of pulsatile cardiopulmonary bypass reported that the number of perfused vessels in the microcirculation was increased compared with a continuous-flow circulation (O'Neil et al 2012;Inamori et al 2013). Importantly, the authors also reported, 'pulsatility resulted in a reduction in the prevalence of pathologic hyper-dynamically perfused vessels' (O'Neil et al 2012).…”

Acute and chronic effects of continuous‐flow support and pulsatile‐flow support

“…For example, Recchia et al and Kassab et al demonstrated that PF increases in vivo coronary flow, in part by triggering NO release. Inamori et al showed the efficacy of PF for enhancing cerebral microvessel perfusion and the effect of NO production on this process. Lazaro et al, Opatrny et al, and von Horn et al observed that PF preserved kidney perfusion during organ storage and kidney function after autotransplantation.…”