Spontaneous coronary artery dissection diagnostic approach

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Arzu Kalayci, M.D. [2]

Synonyms and keywords: SCAD

Overview

Coronary angiography is the standard for diagnosing spontaneous coronary artery dissection. Adjunctive imaging modalities such as intravascular ultrasonography (IVUS), optical coherence tomography (OCT), computed tomography angiography (CTA), and magnetic resonance angiography (MRA) may offer complementary details for establishing a definitive diagnosis.

Algorithm for Diagnosis of Spontaneous Coronary Artery Dissection in the Setting of Acute Coronary Syndrome: A Scientific Statement From the American Heart Association

Algorithm for diagnosis of spontaneous coronary artery dissection (SCAD) in the setting of acute coronary syndrome.^[1]

Coronary angiography after intracoronary nitrates

Type 1 SCAD
(arterial wall stain, multiple lumens)

Type 2 SCAD
(intramural hematoma, diffuse, smooth stenoses)

Type 3 SCAD
(mimics atherosclerosis)

If diagnostic uncertainty, consider adjunctive diagnostic strategies:

❑  OCT/IVUS if feasible/safe
❑  CT coronary angiography
❑  CTA/MRA/angiographic imaging for extracoronary vasculopathy/FMD
❑  Repeat coronary angiography at 6–8 weeks

Abbreviations: CT, computed tomography; CTA, computed tomography angiography; FMD, fibromuscular dysplasia; IVUS, intravascular ultrasonography; MRA, magnetic resonance angiography; OCT, optical coherence tomography.

Algorithm for Angiographic Diagnosis of Non-Atherosclerotic Spontaneous Coronary Artery Dissection

A stepwise algorithm for diagnosing non-atherosclerotic SCAD has been proposed by Saw et al.^[2]
Clinicians should maintain a high index of suspicion for SCAD and consider early coronary angiography to ensure timely diagnosis and management.
If the pathognomonic appearance of arterial wall stain with multiple radiolucent lumens is evident, then the diagnosis of type 1 SCAD can be established without additional intracoronary imaging.
If type 1 SCAD appearance is not evident, angiographers should then assess for the presence of atherosclerotic changes in other coronary arteries, and consider intracoronary imaging if there is uncertainty as to non-atherosclerotic SCAD.
For diffuse (>20 mm) and smooth stenosis of varying severity suggestive of type 2 SCAD, intracoronary nitroglycerin may be administered to rule out coronary spasm.
If the stenosis remains unchanged after nitroglycerin administration, then optical coherence tomography (OCT) or intravascular ultrasound (IVUS) should be pursued.
If there are concerns of compromising coronary flow with intracoronary imaging, then the stenosis could be reassessed in 4 to 6 weeks for hemodynamically stable patients, as SCAD typically resolves spontaneously.

Algorithm for the Angiographic Diagnosis and Confirmation of Spontaneous Coronary Artery Dissection^[2]

Presence of features that raise suspicion for SCAD?
(click for details)

❑ Myocardial infarction in young women (age ≤50)

❑ Absence of traditional cardiovascular risk factors

❑ Little or no evidence of coronary atherosclerosis

❑ Peripartum state

❑ History of fibromuscular dysplasia

❑ History of connective tissue disorder or systemic inflammation

❑ Marfan’s syndrome

❑ Type 4 Ehlers-Danlos syndrome

❑ Loeys-Dietz syndrome

❑ Cystic medial necrosis

❑ Systemic lupus erythematosus

❑ Crohn’s disease

❑ Ulcerative colitis

❑ Polyarteritis nodosa

❑ Sarcoidosis

❑ Churg-Strauss syndrome

❑ Wegener’s granulomatosis

❑ Rheumatoid arthritis

❑ Giant cell arteritis

Perform early coronary angiography

Presence of type 1 SCAD lesion characteristics?
(click for details)

❑ Contrast staining of arterial wall

❑ Multiple radiolucent lumens

❑ Contrast hang-up or slow clearing from the lumen

YES

NO

Type 1 SCAD most likely

Presence of type 2 SCAD lesion characteristics?
(click for details)

❑ Diffuse lesion (typically >20–30 mm)

❑ Smooth luminal narrowing with varying severity

❑ Involvement of mid to distal segments

YES

NO

Stenosis relieved by intracoronary nitroglycerin?

Look for type 3 SCAD lesion characteristics
(click for details)

❑ Focal or tubular stenosis (typically <20 mm)

❑ Mimics atherosclerosis

❑ Additional features

❑ No atherosclerosis in other arteries

❑ Long lesions (11–20 mm)

❑ Hazy stenosis

❑ Linear stenosis

YES

NO

Type 3 SCAD most likely

❑ Consider OCT or IVUS for definitive diagnosis

❑ Reassess with angiography in 4 to 6 weeks

R/O coronary spasm

Type 2 SCAD most likely