What is the role for angiography in the workup of digital ischemia?

Digital ischemia is an especially serious complication in patients with rheumatic disease, particularly scleroderma but can also be a feature of lupus, vasculitis (ANCA associated, PAN), antiphospholipid syndrome, and rheumatoid vasculitis, among others.

The presence of digital pain with permanent/pervasive pallor and/or cyanosis of the skin of the affected digit is a key clinical sign of impending digital tissue loss. It is critical to quickly determine the likely etiology of the ischemia so that appropriate therapy can be promptly initiated to prevent permanent tissue loss/gangrene. Digital tissue vitality can be threatened by many pathological processes that compromise arterial blood supply.

When trying to understand the etiology and further work up (McMahan and Wigley, PMID 26523153) in these cases, a detailed history (Raynaud’s, known rheumatic disease, medications, drug use, acuity, unilateral vs bilateral involvement, smoking, occupation, risk factors for thrombotic/embolic disease), comprehensive physical examination (including capillaroscopy, Allen’s test, evaluation for bruits, bilateral upper limb pulses and blood pressures) and lab investigations as appropriate (ANA, ENA, Centromere, APLs, ANCAs, ESR, CRP) can be very helpful in pointing to the predominant pathology (thrombosis, vasculopathy, vasculitis, embolic, traumatic, infectious, hematologic) many of which can also be complicated by secondary vasospasm. In the large majority, non-invasive imaging is typically my preferred first step for further evaluation and may include duplex doppler, laser doppler flowmetry, thermography where available. 

In cases of critical digital ischemia, Doppler ultrasound can be very helpful to quickly and accurately diagnose the size of vessels involved and to determine if surgical intervention is a viable option. Angiography is typically indicated in the presence of confirmed large-​vessel pathology to define the anatomy of the causative vascular lesions.

Imaging techniques for angiography include digital subtraction angiography (DSA), CT angiography, and MRI angiography. DSA is invasive, but endovascular procedures can be performed at the same time if necessary. While non-invasive, CT and MRI angiography do not provide perfect visualization of the distal limb vessels in the hands and feet, but can be helpful in diagnosing vasculopathy in the CTDs. MRA can be helpful in evaluating patients with Raynaud’s phenomenon when compared to conventional angiography as vasodilators are often used with conventional angiography and the true degree of vasospasm is often underestimated. CTA and contrast enhance MRA can be helpful in assessing vasculitic etiology, that may benefit from systemic steroids and immunesuppression; and distinguish it from pathology in CTDs, where the vasculopathy warrants aggressive vasodilation, temporary anticoagulation, and prostacyclin therapy.

Angiography is used in specific cases with digital ischemia when

1. The underlying cause is in question (atherosclerosis vs vasculitis vs thrombosis) or,
2. The option of surgery (e.g. Ulnar revascularization in Systemic sclerosis) is being considered. It can assist with confirming the site of vascular occlusion prior to peripheral artery bypass grafts in the hands and feet of patients with severe Raynaud’s.

I recommend utilizing this to define the vascular anatomy of patients with severe digital ischemia who are candidates for angioplasty or surgery. I typically avoid invasive imaging, unless absolutely necessary. Often in these cases, collaborative work up with vascular medicine and interventional radiology is helpful.

In smokers, where thromboangiitis obliterans (Buerger's) is a suspected pathology, some angiographic abnormalities can be pathognomonic (segmental occlusive lesions of the small and medium-sized vessels e.g., digital, palmar, radial, and ulnar arteries, with formation of distinctive small collateral vessels around areas of occlusion). Occlusive, obliterative vascular lesions on angiography have also been seen in limbs of patients with PAN (Stanson et al., PMID 11158650).

Hope that helps!