Abstract

Objectives

Intravenous dipyridamole (DP) can induce transient perfusion abnormalities in the heart but also the brain indicated by brain SPECT. L-arginine can regulate the vascular tone via nitric oxide (NO). Therefore, we examined cerebral blood volume (CBV) by perfusion MRI and L-arginine level before and after DP stress in patients, who developed transient neurological signs, and compared these to unaffected patients.

Design

A total of nine patients with ischemic coronary disease after myocardial perfusion scintigraphy were selected for this prospective pilot study. Four had DP-induced transient mild neurologic signs during myocardial perfusion scintigraphy, while five had no neurological signs. By using perfusion MRI in both groups in a second stage, we examined CBV in identical areas of the two hemispheres before and during DP stress. Besides, pre-and post-stress L-arginine serum levels were also analyzed by high-performance liquid chromatography. Trial registration: NCT03688815.

Results

CBV in the sensory-motor area at baseline was significantly higher in patients with DP-induced transient neurological signs compared to patients without signs (p = 0.028). Intravenous DP normalized the higher perfusion by decreasing CBV, and also increased serum L-arginine level (p = 0.001).

Conclusions

Intravenous DP changed the CBV accompanied by a systemic elevation of L-arginine: this indicates a direct vasorelaxing effect on brain vessels, and an indirect vasodilator effect through L-arginine release presumably via NO. In areas with decreased CBV before DP, such double effects caused transient neurological symptoms presumably due to steal phenomenon. Therefore, intravenous DP may have a potential to identify patients with high risk for cerebral ischemia.

中文翻译：

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显性缺血性冠状动脉疾病患者无症状脑微循环异常的检测：脑灌注 MRI 研究联合双嘧达莫应激

摘要

目标

静脉注射双嘧达莫 (DP) 可诱导心脏以及大脑 SPECT 指示的短暂灌注异常。L-精氨酸可以通过一氧化氮 (NO) 调节血管张力。因此，我们通过灌注 MRI 和 L-精氨酸水平检查了患者 DP 应激前后的脑血容量 (CBV)，这些患者出现了短暂的神经系统体征，并将这些与未受影响的患者进行了比较。

设计

这项前瞻性试验研究共选择了 9 名心肌灌注显像后患有缺血性冠状动脉疾病的患者。4 人在心肌灌注闪烁显像期间有 DP 诱导的短暂轻微神经系统体征，而 5 人没有神经系统体征。通过在第二阶段在两组中使用灌注 MRI，我们在 DP 压力之前和期间检查了两个半球相同区域的 CBV。此外，还通过高效液相色谱分析了应激前后的 L-精氨酸血清水平。试用注册：NCT03688815。

结果

与没有体征的患者相比，有 DP 诱导的短暂神经系统体征的患者基线感觉运动区的 CBV 显着更高（p  = 0.028）。静脉内 DP 通过降低 CBV 使较高的灌注正常化，并且还增加了血清 L-精氨酸水平 ( p  = 0.001)。

结论

静脉内 DP 改变了 CBV，伴随着 L-精氨酸的全身升高：这表明对脑血管有直接的血管舒张作用，并且可能通过NO释放 L-精氨酸产生间接的血管扩张作用。在 DP 前 CBV 降低的地区，这种双重作用引起了可能是由于偷窃现象引起的短暂的神经系统症状。因此，静脉内 DP 可能具有识别脑缺血高危患者的潜力。