While up to 90% of patients with spontaneous coronary artery dissection (SCAD) are younger women with no prior risk factors for heart disease, men can also develop SCAD, according to a new analysis. Men with SCAD are more likely to be younger and have a physical trigger as compared to women with SCAD, but men are less likely to have fibromuscular dysplasia (FMD), depression or other emotional triggers. These findings from the Canadian SCAD Study were reported by Cameron McAlister, MBChB, of Vancouver General Hospital, University of British Columbia, and colleagues in a manuscript published Monday online and in the Oct. 24 issue of JACC: Cardiovascular Interventions. In the early 1900s, SCAD was initially thought to come from pregnancy, and over time recorded instances of SCAD have been increasing. Two mechanisms have been proposed for the occurrence of SCAD—an intimal tear or a vessel-wall bleeding. Vessel-wall bleeding often creates an intramural hematoma which is the most common appearance of SCAD. Intense emotional and/or physical stress is also associated with SCAD episodes. SCAD is estimated to cause 1% to 4% of acute coronary syndrome (ACS) cases and may cause up to 35% of myocardial infarctions in women under 50 years of age. This analysis focused on the research gaps when studying both men and women with SCAD, as well as potential SCAD triggers and predisposing arteriopathies. There were 1,173 participants, of whom 123 were men. The cardiovascular risk factors for men and women were similar, including the percentages with hypertension (men 35% vs. women 34.7%) and a family history of coronary artery disease (men 32% vs. women 36.8%). There were some significant differences in medical histories. At baseline, men with SCAD had similar cardiovascular risk factors to women but were younger (mean age for men = 49.4 ± 9.6 years, mean age for women = 52.0 ± 10.6 years; P = 0.01). There was no significant difference in prior confirmed SCAD. Men had a lower rate of prior MI than women (0.8% vs. 7.0%; p=0.005), and men were less likely to have fibromuscular dysplasia (FMD; 27.8% vs. 52.7%; p=0.001) or depression (9.8% vs. 20.2%; p=0.005). Men were emotional stress (35.0% vs. 59.3%; p < 0.001) or high score on the Perceived Stress Scale (3.5% vs. 11.0%; p = 0.025), but were more likely to report isometric physical stress (40.2% vs 24.0%; p=0.007), on the questionnaires presented to 95.1% of men and 96.9% of women. A total of 1,403 discrete SCAD lesions were found, and 19 men and 188 women had multivessel SCAD. Men had more frequent circumflex artery instances (44.4% vs 30.9%; P = 0.001) and less frequent right coronary artery instances ((11.8% vs 21.7%; P = 0.0054). The most common location for SCAD in both populations was the left anterior descending artery (41.7% of men, 46.1% of women). At a median follow-up of 3 years (interquartile ratio: 2.0-3.8 years), men had fewer hospital presentations with chest pain (10.6% vs 24.8%; P < 0.001), and there were no differences between men and women concerning in-hospital events or follow-up major adverse cardiovascular events (7.3% vs 12.7%; P = 0.106). In an accompanying editorial, Fernando Alfonso, MD, PhD, and Teresa Bastante, MD, of the Universidad Autónoma de Madrid, highlighted the improvements the medical community has made in understanding the pathophysiology and treatment of SCAD. The editorial applauds the Vancouver study for its large sample size, FMD screening rate and thorough clinical assessments of their participants, but noted that men are frequently misdiagnosed when it comes to SCAD studies—men, for instance, may have atherosclerotic coronary artery disease. SCAD, as a condition, is often misdiagnosed in both men and women. However, women are more likely to have more atypical chest pain, and the editorial notes that this could have other nonatherosclerotic causes. The editorial also notes that further studies would be needed to dissolve any chance findings about vessel distribution in men, as previous studies have shown that men have relatively equal vessel distribution for SCAD. “The current study provides interesting and novel insights on the perception of stress and depression in women,” Alfonso and Bastante wrote. “Despite our advances in understanding of SCAD, we should humbly recognize that we do not know the etiology and pathophysiology of this elusive condition and why men are less frequently affected.” Sources: McAlister C, Alfadhel M, Samuel R, et al. Differences in Demographics and Outcomes Between Men and Women With Spontaneous Coronary Artery Dissection. JACC Cardiovasc Interv 2022;15:2052–2061. Alfonso F, Bastante T. Spontaneous Coronary Artery Dissection in Men: So Rare? So Different? JACC Cardiovasc Interv 2022;15:2062–2065. Image Credit: 7activestudio – stock.adobe.com