Table 5.

Diagnostic modalities evaluating stenosis degree in randomized trials and guidelines

		Stenosis degree cutoff for carotid artery stenting
		≥50%	≥60%	≥70%	≥80%
Randomized trials
	SAPPHIRE [9]				DUS
	CREST [10]		Angiography*	DUS
	ACT [11]			DUS; Angiography*
	ACST-2 [12]		DUS
	SPACE-2 [13]	DUS
Guidelines from
	ESVS (2009) [22]			-†
	AHA/ASA (2011) [23]		Angiography*	DUS	CTA or MRA‡
	ESC (2011) [24]		DUS; CTA; and/or MRA
	AHA/ASA (2014) [26]		Angiography*	DUS
	ESVS (2017) [1]		DUS; CTA; and/or MRA
	German/Austrian society (2020) [27]		DUS§
	SVS (2021) [28]			DUS|
	ESO (2021) [29]		-†

SAPPHIRE, Stenting and Angioplasty with Protection in Patients at High Risk for Endarterectomy; DUS, duplex ultrasonography; CREST, Carotid Revascularization Endarterectomy vs. Stenting Trial; ACT, Asymptomatic Carotid Trial; ACST, Asymptomatic Carotid Surgery Trial; SPACE, Stent-Protected Angioplasty vs. Carotid Endarterectomy; ESVS, European Society for Vascular Surgery; AHA, American Heart Association; ASA, American Stroke Association; CTA, computed tomography angiography; MRA, magnetic resonance angiography; ESC, European Society of Cardiology; SVS, Society of Vascular Surgery; ESO, European Stroke Organization.

^*Angiography refers to catheter angiography;

^†Modalities were not specified;

^‡Only for stenosis of 50%–69% on duplex ultrasonography;

^§If there is any doubt about grading, MRA and CTA may be performed;

^|If ultrasonography results are equivocal or may be inaccurate, additional imaging with CTA, MRA, or digital subtraction angiography may be considered.