Vascular diagnostics for Raynaud's phenomenon

Abstract

Raynaud's phenomenon (RP) is common, and in most patients is primary (idiopathic) when due to reversible vasospasm and does not progress to irreversible tissue injury. However, in those patients for whom RP is secondary to an underlying disease (eg, systemic sclerosis or atherosclerosis), progression to digital ulceration or critical ischemia can occur. Therefore, the key question for the clinician is Why does this patient have RP? Vascular diagnostics play a key role in answering this. In this review, we firstly discuss the different vascular investigations relevant to clinical practice: nail fold capillaroscopy (including the different methodologies for examining the nail fold capillaries, and the role of capillaroscopy in helping to differentiate between primary and systemic sclerosis-related RP), thermography (available in specialist centers), and evaluation of large vessel disease (for example, due to atherosclerosis). We then discuss research tools, mainly laser Doppler methods, including laser Doppler imaging and laser speckle contrast imaging. These are commercially available as complete imaging systems and are (relatively) easy to use. The main current goal in vascular imaging research is to validate these novel state-of-the-art techniques as outcome measures of digital vascular disease, and then apply them in early and later phase studies of new treatment approaches, thus facilitating