Evaluation of Peripheral Microcirculatory Hemodynamic
Changes During Myocardial Ischemia

Investigators: Weizman-Shammai E.1, Ovadia-Blechman Z.1,
Sharir T.2, Chouraqui P.2, Walden R.3, Eldar M.1
  1. Neufeld Cardiac Research Institute,
  2. Nuclear Cardiology Unit, Heart Institute, Tel Hashomer
  3. Vascular Institute, Tel Hashomer

Hemodynamic changes in the microcirculation are difficult to measure due to the small dimensions and special architecture of the microvessels. At the Neufeld Cardiac Research Institute, we have devised a non-invasive system that measure hemodynamic changes in the microcirculation (LPT system).

The LPT consists of: Laser Doppler Flowmeter (LDF), Photoplethysmograph (PPG) and Transcutaneous Oxygen Tension (tc-PO2), which measure flux of red blood cells, amount of red blood cells and oxygen tension, respectively. Each of the LPT components was proved to be sensitive to small hemodynamic changes in the microcirculation and is used for different clinical applications.

The combined LPT system provides vital information from each component, which can be compiled to give a general picture of the microcirculation in different situations, such as myocardial ischemia.

The influence of myocardial ischemia on the coronary blood flow is well known, but its influence on peripheral hemodynamic variables in the microcirculation was not investigated yet.

In this study we found that the LPT system which is described above, provides sufficient data in order to diagnose hemodynamic changes in the microcirculation during myocardial ischemia in rest and exercise.

The study was held with the cooperation of the Nuclear Cardiology Unit, Heart Institute, Tel Hashomer and included 47 patients who were divided into two groups according to the results of their myocardial Thallium SPECT imaging:
1. Negative imaging group – 27 non-ischemic patients
2. Positive imaging group – 20 ischemic patients

Peripheral microcirculation variables, heart rate and blood pressure were continuously measured at rest, at the end of exercise and during recovery period.

The results indicated distinct differences between the peripheral variables of the two groups along time, although no changes were found between the systemic variables (heart rate and blood pressure) of the two groups.

In conclusion, the LPT system is high sensitive to any hemodynamic changes that occur in the microcirculation during myocardial ischemia.

The LPT system may be useful in diagnosing non-invasively myocardial ischemia of variable severity during rest and exercise, even in ischemic conditions, which are not recognized by the measurement of the systemic variables.