Monitoring functional disorders of microcirculation using laser Doppler flowmetry in patients with chronic venous insufficiency class 2 according to CEAP classification before and after varicose veins surgery

Introduction:
Laser Doppler flowmetry is a sensitive modern method for evaluating the function of small veins which allows for the detection and assessment of early pathological changes in microcirculation. The method uses a low power laser beam which is emitted into the tissue where it is reflected and further recollected and analysed. The objective of the study was to compare laser Doppler flowmetry parameters for patients with chronic venous insufficiency (class 2 according to CEAP, primary varices) prior to and 1 month after surgery of varicose veins.


Methodology and patient sample:
The examination was performed by a Periflux laser Doppler apparatus made by Perimed. Blood flow was examined on the dorsal side of foot fingers. A total of 42 patients were examined prior to and one month following the varicose veins surgery, of whom 28 women and 14 men. The mean age of the patient sample was 49 years. A 45 minute pre-op and postop recording of the limb was made for each patient. The protocol consisted of a 10 minute recording in rest, followed by a 4 minute ischemisation of the limb with the use of a blood pressure measuring cuff, subsequent release of the cuff, a 15 minute recording of the reperfusion and a test of vasodilatation using nitrate, and a 10 minute recording following vasodilatation. Evaluation was performed for a 4 minute period at the end of the initial rest period, for reperfusion after the release of the cuff and for the interim period of rest immediately preceding the application of nitrate, and finally for a 5 minute period after nitrate application. Statistical evaluation was performed for data acquired during the movement of blood elements and data acquired in the frequency analysis of the movement of the blood vessel wall. 3 variables were chosen for the statistical evaluation of the blood cell movement data: "the area under the curve", "the mean value of the deviation" and "the percentage change" in the different phases of the measurement, i.e. as compared with the rest recording: comparing the ischemisation and the rest recordings, comparing the vasodilatation and the rest recordings, and comparing the restitution and the rest recordings. The above variables were not assessed as absolute numbers but as the difference of values before and after the surgery. The above differences were tested in the Wilcoxon test. The intensity of blood vessel movements in the frequency range from 0.008 to 0.200 Hz and 0.210-0.420 Hz was evaluated in frequency analyses.

Results:
Significant differences in peripheral microcirculation in lower limbs were found in the evaluation of data acquired during the movement of the different blood elements before and after varicose vein surgery (p = = NS). On the contrary, evaluation of frequency analysis for both the operated and non-operated limb shows a decrease in spontaneous arterial reactivity after varicose vein surgery. This decrease is statistically significant in the frequency range from 0.102 to 0.228 on operated limbs after the removal of a varix in a T1 test (i. e. after reperfusion) as compared with the values before the surgery (p < 0.05).

Conclusion:
Varicose vein surgery results in the reduction of spontaneous vasomotion in the periphery of the operated limb.

Keywords: Laser Doppler flowmetry; microcirculation disorders; movement of blood elements; arterial vasomotion; varicose vein surgery