Vascular Occlusive Syndromes of the Upper Extremity Workup

Updated: Oct 03, 2019
  • Author: Bradon J Wilhelmi, MD; Chief Editor: Harris Gellman, MD  more...
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Workup

Imaging Studies

Handheld Doppler ultrasonography (US) is used to analyze variation in the pulse waveform by reflections of sound generated by intraluminal moving red blood cells. The loudness and pitch of the audible signal is determined by the intraluminal flow. This modality allows delineation of venous versus arterial pulses.

B-mode Doppler US allows evaluation of pulsatile flow, which is depicted by a triphasic flow, involving an initial systolic upstroke followed immediately by a transient downstroke flow reversal and finally a minor upstroke elastic recoil. Various monophasic patterns allow differentiation of stenosis versus occlusion of vessels.

Color duplex images are useful for evaluating masses and for differentiating ganglia, aneurysms, and pseudoaneurysms.

Radionuclide imaging can be used to obtain a two-dimensional (2D) assessment of the vascular anatomy, as well as to ascertain temporal patterns of perfusion. A radionuclide, such as technetium-99m pertechnetate, is injected intravenously, and three serial images are taken. The first image is similar to an angiogram, the second involves serial pictures obtained over a 1.5-minute period that are used to assess blood pooling and flow dynamics, and the third mimics a bone scan.

This modality allows evaluation of vaso-occlusive diseases, such as aneurysms, as well as vasospastic diseases. It has also been used as a prognostic test for determining extent of frostbite injury or even degree of tissue viability following electrical injury. Absence or presence, including delay, of radiotracer in zones distal to occluded vessels allows for evaluation of the severity of the occlusion.

Vital capillaroscopy is a noninvasive modality used to assess integrity of nutritional papillary capillaries. With the aid of epillumination microscopic technique and specialized computer manipulations, qualitative and quantitative information can be obtained about the status of these terminal vessels. Currently, no other diagnostic tool is capable of providing assessment of these microvessels. [1, 2]

High-resolution magnetic resonance angiography (MRA) allows visualization of arterial and venous structures. [3, 4, 5] The advantage of MRA is that it provides vivid images without the need for arterial vascular access and without patient exposure to ionizing radiation or potentially allergy-inducing contrast dyes.

In a study reviewing the use of multidetector computed tomographic angiography (MDCTA) in the assessment of combat casualties with vascular injuries, White et al found that MDCTA yielded high-resolution images useful in delayed evaluation of vascular injuries and that the presence of metallic fragments or orthopedic hardware did not significantly interfere with MDCTA. [6] They concluded that MDCTA is a reliable and promising alternative to traditional arteriography for evaluating clinically occult vascular trauma.

Finally, contrast angiography remains the criterion standard, most accurately revealing detailed vascular anatomic information. With computer manipulation, it is possible to evaluate flow direction, source of collateral flow, degree of retrograde filling, and even venous outflow. Relative indications for arteriography include suspicion of partial arterial injury resulting in an intimal flap, proximal traction injury, distal vessel occlusion caused by embolic showering, and pseudoaneurysm formation.

Despite its obvious advantages, this modality is used sparingly because it is costly and associated with various complications. Complications can include arterial wall injury, local vasospasm, distal embolic showering, and contrast-induced allergic reaction.

In general, the various discussed modalities provide the clinician with further evidence of vascular pathology, especially when patients are evaluated with and without vascular stressors. In fact, most clinicians recommend completion of vascular studies before, during, and after controlled exposure to stressors, such as thermal variation, induced anoxia, or emotional lability.

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Other Tests

Digital plethysmography allows assessment of digital volume changes over time. Serial volume-change patterns can be used to differentiate vasospastic from vaso-occlusive disease. Qualified vascular technicians are required for these analyses. Segmental arterial pressures are obtained by comparing the digital brachial index (DBI) and/or radial brachial index (RBI)–ulnar brachial index (UBI) pressures to the brachial artery pressure. Specifically, DBI or RBI ratios lower than 0.7 indicate inadequate blood perfusion of end organs and encourage intervention.

Digital plethysmography is a valuable and reliable tool for assessing the severity of vasospasm, either in isolation or as part of a combined occlusive/vasospastic disorder (eg, scleroderma). The technique is also particularly valuable as a tool for objectifying cold-induced vasospasm in vibration-induced white finger syndrome (VWFS) secondary to chronic hand vibrations.

Skin surface temperatures can be used to estimate digital perfusion. [7] This modality, however, is only reliable for physiologic temperatures within the range of 20-30°C. Its primary value is to assess the efficacy of stellate ganglion block to enhance digital perfusion as a preoperative indication of the potential value of digital sympathectomy. An increase of more than 1-2°C suggests an ischemia-related condition (as seen with scleroderma and Raynaud disease) that could potentially be improved.

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