一种非侵入性测定中心主动脉压变化率新方法的验证

Gorenberg M, Marmor A

Department of Nuclear Cardiology and Nuclear Medicine, Sieff Government Hospital, Safed, Israel.

J Med Eng Technol. 2008 Jul-Aug;32(4):257-62. doi: 10.1080/03091900600824416.

INTRODUCTION

One of the most sensitive indices of myocardial contractility is represented by the rate of increase of intraventricular pressure during isovolumetric contraction (dP/dt) and (dP/dt(ejc)), which represents the rate of change of pressure during ejection. Today these parameters can be obtained only by invasive catheterization methods. We developed a novel technique that leads to the non-invasive reconstruction of the central aortic pressure. The technique is based on the concept of applying multiple successive occlusive pressures on the brachial artery from peak systole to diastole using an inflatable cuff and plotting the values against time intervals. The hypothesis is that the time intervals required for the aortic pressure wave to overcome a given occlusive brachial pressure applied by a sphyngomanometer on the arm are equal to time needed to reach the same pressure in the central aorta plus the propagation time to the brachial point, which is constant in the same patient throughout the measurements.

METHODS AND RESULTS

We tested the hypothesis using an animal experiment. The new non-invasive device was mounted on the left forelimb of the animal. A Millar pressure transducer catheter was inserted to the aorta and the aorta pressure was recorded at time intervals of 1 ms. A second catheter was inserted into the coronary arteries and used to create controlled occlusion of the arteries using a balloon inflated to 10 atm. Measurements were obtained before the intervention was started, and throughout the sequence of repeated occlusions and deflations. At the end of the sequence, IV dobutamine was administered and results were monitored for 10 min while the heart rate and blood pressure were rising. Non-invasive dP/dt(ejc) was reduced typically by 20% in response to balloon inflation. In long occlusion periods, stabilization and sometimes recovery of dP/dt(ejc) is observed. By plotting dP/dt(ejc) measured by the new non-invasive device versus catheter measurements a correlation factor of 0.843 was found.

CONCLUSION

A newly developed method of non-invasive measurement of central dP/dt has been found to correlate to invasive measurements in an animal model.

引言

心肌收缩力最敏感的指标之一是等容收缩期室内压的上升速率（dP/dt）以及代表射血期压力变化速率的（dP/dt(ejc)）。目前，这些参数只能通过有创导管插入术获得。我们开发了一种新技术，可实现中心主动脉压的无创重建。该技术基于这样的理念：使用可充气袖带从收缩期峰值到舒张期在肱动脉上施加多个连续的闭塞压力，并将这些值与时间间隔进行绘图。其假设是，主动脉压力波克服血压计施加在手臂上的给定闭塞肱动脉压力所需的时间间隔，等于在中心主动脉达到相同压力所需的时间加上传播到肱动脉点的时间，在同一患者的整个测量过程中，该传播时间是恒定的。

方法与结果

我们通过动物实验对该假设进行了测试。将新的无创装置安装在动物的左前肢上。将Millar压力传感器导管插入主动脉，并以1毫秒的时间间隔记录主动脉压力。将另一根导管插入冠状动脉，使用充气球囊至10个大气压来控制动脉闭塞。在干预开始前以及整个重复闭塞和放气序列过程中进行测量。在序列结束时，静脉注射多巴酚丁胺，并在心率和血压上升的同时监测结果10分钟。无创dP/dt(ejc)通常会因球囊充气而降低20%。在长时间闭塞期，可观察到dP/dt(ejc)的稳定，有时还会恢复。通过绘制新无创装置测量的dP/dt(ejc)与导管测量值的关系图，发现相关系数为0.843。