颈内注射维拉帕米可降低人体近端和远端脑血管阻力。

Joshi Shailendra, Meyers Philip M, Pile-Spellman John, Wang Mei, Sahlein Daniel H

Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York 10032, USA.

Anesthesiology. 2004 Apr;100(4):774-81. doi: 10.1097/00000542-200404000-00005.

BACKGROUND

The authors determined the segmental effects of intracarotid verapamil in human subjects by using a novel method of measuring proximal and distal cerebrovascular resistance. Their hypothesis was that intracarotid verapamil, a calcium channel-blocking drug that augments cerebral blood flow and reverses arterial spasm, would decrease both the proximal-conductance and the distal-arteriolar resistance.

METHODS

Coaxial catheters were transfemorally floated into internal carotid and middle cerebral arteries during cerebral angiography. Pressures were recorded in the femoral, internal carotid, and middle cerebral arteries. Hemispheric cerebral blood flow was measured by the intracarotid Xe injection technique. Cerebrovascular resistance was measured for the proximal and distal arteries. Cerebral blood flow and hemodynamic data were recorded during intracarotid infusion of saline and verapamil (1 mg/min) for 5 min. Transcranial Doppler blood flow velocity in the middle cerebral artery was also recorded.

RESULTS

Intracarotid verapamil increased in 133Xe cerebral blood flow from 43 +/- 11 to 59 +/- 11 ml.100 g(-1).min(-1) (P = 0.001; n = 9). The cerebrovascular resistance measured for the proximal and distal arteries decreased from 0.17 +/- 0.95 to 0.12 +/- 0.75 and from 1.63 +/- 0.78 to 1.03 +/- 0.33 mmHg.ml(-1).100 g(-1).min(-1) (P < 0.01), respectively. The calculated proximal-conductive and distal-arteriolar (pial plus parenchymal) resistances showed a similar decrease. Transcranial Doppler measurements (n = 5) underestimated the effects of intracarotid verapamil that were consistent with an increase in middle cerebral artery diameter.

CONCLUSIONS

Intracarotid verapamil decreases both the proximal-conductance and the distal-arteriolar resistance. Furthermore, it is feasible to investigate segmental effects of drugs in human subjects by measuring changes in pressure gradients within the cerebral arteries and simultaneous Xe cerebral blood flow measurements.

背景

作者通过一种测量颈内动脉近端和远端脑血管阻力的新方法，确定了颈内注射维拉帕米对人体受试者的节段性影响。他们的假设是，颈内注射维拉帕米，一种可增加脑血流量并逆转动脉痉挛的钙通道阻滞剂，会降低近端血管传导性和远端小动脉阻力。

方法

在脑血管造影期间，通过股动脉将同轴导管漂浮至颈内动脉和大脑中动脉。记录股动脉、颈内动脉和大脑中动脉的压力。通过颈内注射氙技术测量半球脑血流量。测量近端和远端动脉的脑血管阻力。在颈内注射生理盐水和维拉帕米（1毫克/分钟）5分钟期间，记录脑血流量和血流动力学数据。还记录大脑中动脉的经颅多普勒血流速度。

结果

颈内注射维拉帕米使133Xe脑血流量从43±11增加到59±11毫升·100克-1·分钟-1（P = 0.001；n = 9）。近端和远端动脉测量的脑血管阻力分别从0.17±0.95降至0.12±0.75以及从1.63±0.78降至1.03±0.33毫米汞柱·毫升-1·100克-1·分钟-1（P < 0.01）。计算得出的近端血管传导性和远端小动脉（软脑膜加实质）阻力显示出类似的降低。经颅多普勒测量（n = 5）低估了颈内注射维拉帕米的效果，这与大脑中动脉直径增加一致。