How useful are vascular studies in Raynauds Phenomenon
Patients with primary RP rarely, if ever, require noninvasive or invasive vascular studies. In patients with SSc or other secondary causes of RP, vascular studies may be helpful in a subset of patients to clarify the extent and severity of vessel involvement. Clinical scenarios in which vascular studies may be helpful include asymmetric finger or hand involvement, high clinical suspicion of secondary causes of RP such as thromboembolism or Buerger’s disease, an abnormal Allen’s test suggestive of proximal artery disease, or severe disease-resistant to initial vasodilator therapy.
Noninvasive studies include brachial-finger index measurement (gradients over 20 mm Hg suggest a proximal fixed obstruction), Doppler ultrasound studies, and finger photoplethysmography (which can generate pulse-volume recordings). Significant vascular disease in SSc is typically confined to the level of the palmar arch and digital arteries (“vascular pruning”), but more proximal involvement can occur and may be suggested by an abnormal Allen’s test and confirmed with vascular studies (see Question 20). Invasive angiography or magnetic resonance angiography may reveal an embolic source or proximal vessel disease such as with vascular thoracic outlet syndrome (vTOS), but these studies are often unnecessary in the initial evaluation of secondary RP. In patients with suspected vTOS, chest radiography may demonstrate a cervical rib as well.
