Other Clinical Tests

Capillary Refill

With the patient supine and the great toes together, both toes are gripped by the examiner using one hand and compressed. On release, the toes should change symmetrically from white to pink in less than 5 seconds. Asymmetry suggests arterial disease on the slowest side.

Buerger's Test

This is a test for severe chronic arterial occlusive disease. With the patient supine the straight legs are raised as far as possible. In arterial disease, there is extreme pallor of the feet in this position (Fig. 2.5). The legs are then placed on the examination bench and the patient is told to sit with the legs dependent over the side of the bench. Where there is severe chronic arterial disease, the feet become suffused with a deep ruddy red color, commonly described as "sunset foot." This is caused by ischemic maximal dilation of the arteriolar bed of the skin, allowing the skin to fill with partially oxygenated blood (Fig. 2.6).

Trendelenburg Test

In cases where incompetence of the saphe-nofemoral junction is suspected as a major

CLINICAL EVALUATION OF PATIENTS WITH VASCULAR DISEASE

CLINICAL EVALUATION OF PATIENTS WITH VASCULAR DISEASE

Figure 2.6. Dependent rubor.The leg has been placed dependent over the side of the bed, and is extremely hyperemic.

cause of superficial varicose veins, the patient is asked to lie supine and raise the affected limb to about 45 degrees. Venous blood is "milked" proximally by firm stroking of the leg to empty all of the superficial veins. A tourniquet is applied as proximally as possible to occlude the superficial venous system. The patient is then asked first to sit up and swing the legs over the side of the examination couch, and then to stand. Where saphenofemoral incompetence is the major cause of superficial varicosities, the varicosities will remain collapsed. It is usual for the superficial veins to fill slowly, but rapid filling of the varicosities with the tourniquet in place indicates significant perforator disease distal to the tourniquet. It is possible to localize incompetent perforating veins by repeating the test with the tourniquet just above the knee. In this case calf varicosities will remain collapsed if the guilty perforating vein is between the saphenofemoral junction and the tourniquet. If the incompetent perforating vein is below the knee, the below knee varices will fill rapidly. Although the Trendelenburg method is somewhat insensitive in localizing incompetent perforating veins, it can provide useful clinical information. For more accurate localization of incompetent thigh perforators, and for all those in the calf, it is best to use duplex examination.

Fixed Wave Doppler Examination

A number of small and portable battery-operated machines are available, operating at frequencies between 5 and 10 MHz depending on the depth of penetration required (Fig. 2.7). In each case the signal from the insonation of the examined artery is converted into an audible sound from a built-in speaker. Normally the signal has a "triphasic" sound. Although it is possible to use the Doppler simply to locate an artery, the most common use is to measure the blood pressure at the periphery of a limb. For this, the Doppler machine is used in the same way as a stethoscope when measuring the blood pressure using Korotkoff sounds. A blood pressure cuff is placed around the limb proximal to the artery to be examined. The artery is then insonated and the cuff inflated above the systolic pressure. As the cuff is deflated, the signal returns, and the pressure at which this happens is noted. When the pressure in all the required arteries has been measured, the pressure in the brachial artery is measured using the same technique. The ratio between the ankle pressure and the brachial pressure is known as the ankle-brachial index (ABI). The ABI in normal patients without arterial occlusive disease is greater than 1.

Handheld Doppler examination is also useful in the diagnosis of superficial venous disease

Figure 2.7. An example of the type of handheld Doppler device suitable for use in the clinic.

VASCULAR SURGERY

to confirm the incompetence of the saphe-nofemoral or saphenopopliteal junctions, and to localize incompetent perforating veins. At each of the saphenous junctions, there is physiological retrograde flow into the superficial system of under 1 second' duration, which is audible using a handheld Doppler machine. If the reflux is of longer duration, it is indicative of pathological incompetence of the junction. With an experienced operator, it is possible to localize incompetent perforating veins.

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