Canadian spontaneous coronary artery dissection cohort study: in-hospital and 30-day outcomes.

AIMS: Spontaneous coronary artery dissection (SCAD) was underdiagnosed and poorly understood for decades. It is increasingly recognized as an important cause of myocardial infarction (MI) in women. We aimed to assess the natural history of SCAD, which has not been adequately explored. METHODS AND RESULTS: We performed a multicentre, prospective, observational study of patients with non-atherosclerotic SCAD presenting acutely from 22 centres in North America. Institutional ethics approval and patient consents were obtained. We recorded baseline demographics, in-hospital characteristics, precipitating/predisposing conditions, angiographic features (assessed by core laboratory), in-hospital major adverse events (MAE), and 30-day major adverse cardiovascular events (MACE). We prospectively enrolled 750 SCAD patients from June 2014 to June 2018. Mean age was 51.8 ± 10.2 years, 88.5% were women (55.0% postmenopausal), 87.7% were Caucasian, and 33.9% had no cardiac risk factors. Emotional stress was reported in 50.3%, and physical stress in 28.9% (9.8% lifting >50 pounds). Predisposing conditions included fibromuscular dysplasia 31.1% (45.2% had no/incomplete screening), systemic inflammatory diseases 4.7%, peripartum 4.5%, and connective tissue disorders 3.6%. Most were treated conservatively (84.3%), but 14.1% underwent percutaneous coronary intervention and 0.7% coronary artery bypass surgery. In-hospital composite MAE was 8.8%; peripartum SCAD patients had higher in-hospital MAE (20.6% vs. 8.2%, P = 0.023). Overall 30-day MACE was 8.8%. Peripartum SCAD and connective tissue disease were independent predictors of 30-day MACE. CONCLUSION: Spontaneous coronary artery dissection predominantly affects women and presents with MI. Despite majority of patients being treated conservatively, survival was good. However, significant cardiovascular complications occurred within 30 days. Long-term follow-up and further investigations on management are warranted.

Diagnostic accuracy and discrimination of ischemia by fractional flow reserve CT using a clinical use rule: results from the Determination of Fractional Flow Reserve by Anatomic Computed Tomographic Angiography study.

BACKGROUND: Fractional flow reserve (FFR) is the gold standard for determining lesion-specific ischemia. Computed FFRCT derived from coronary CT angiography (coronary CTA) correlates well with invasive FFR and accurately differentiates between ischemia-producing and nonischemic lesions. The diagnostic performance of FFRCT when applied in a clinically relevant way to all vessels ≥ 2 mm in diameter stratified by sex and age has not been previously examined. METHODS: Two hundred fifty-two patients and 407 vessels underwent coronary CTA, FFRCT, invasive coronary angiography, and invasive FFR. FFRCT and FFR ≤ 0.80 were considered ischemic, whereas CT stenosis ≥ 50% was considered obstructive. The diagnostic performance of FFRCT was assessed following a prespecified clinical use rule which included all vessels ≥ 2 mm in diameter, not just those assessed by invasive FFR measurements. Stenoses <30% were assigned an FFR of 0.90, and stenoses >90% were assigned an FFR of 0.50. Diagnostic performance of FFRCT was stratified by vessel diameter, sex, and age. RESULTS: By FFR, ischemia was identified in 129 of 252 patients (51%) and in 151 of 407 vessels (31%). Mean age (± standard deviation) was 62.9 ± 9 years, and women were older (65.5 vs 61.9 years; P = .003). Per-patient diagnostic accuracy (83% vs 72%; P < .005) and specificity (54% vs 82%, P < .001) improved significantly after application of the clinical use tool. These were significantly improved over standard coronary CTA values before application of the clinical use rule. Discriminatory power of FFRCT also increased compared with baseline (area under the receiver operating characteristics curve [AUC]: 0.93 vs 0.81, P < .001). Diagnostic performance improved in both sexes with no significant differences between the sexes (AUC: 0.93 vs 0.90, P = .43). There were no differences in the discrimination of FFRCT after application of the clinical use rule when stratified by age ≥ 65 or <65 years (AUC: 0.95 vs 0.90, P = .10). CONCLUSIONS: The diagnostic accuracy and discriminatory power of FFRCT improve significantly after the application of a clinical use rule which includes all clinically relevant vessels >2 mm in diameter. FFRCT has similar diagnostic accuracy and discriminatory power for ischemia detection in men and women irrespective of age using a cut point of 65 years.