Giannoulatou, Eleni

Abstract Spontaneous coronary artery dissection is an unusual, but increasingly recognized, cause of acute coronary syndrome. It is a potentially fatal disorder that predominantly (>90% of cases) affects women, who are about 20 years younger (age 45–52 years) than those presenting with an acute coronary syndrome due to atherosclerotic coronary artery disease, and is the commonest cause of myocardial infarction associated with pregnancy. With the advent of improved coronary artery imaging modalities, including invasive coronary angiography, intravascular ultrasonography (IVUS), and optical coherence tomography (OCT), spontaneous coronary artery dissection is being increasingly diagnosed. It is typically due to a spontaneous bleed in the tunica media of an epicardial coronary artery, with or without an intimal tear, that results in an intramural haematoma; the latter, in turn causing a separation or dissection of the lamellae formed by the layers of smooth muscle cells of the tunica media, which can propagate longitudinally. Although coronary artery dissection can be due to atherosclerotic disease that may, in fact, present spontaneously, or to trauma, or guidewire-induced intimal injury, the understanding that the entity now known as spontaneous coronary artery dissection is an idiopathic disorder that is not associated with atherosclerosis or trauma, and is not iatrogenic, is one that has emerged only relatively recently (last 10–15 years). This raises the question, what is the provenance of spontaneous coronary artery dissection as it is now defined and understood? Here, this issue is addressed by a detailed consideration of the medical literature from 1800.

Abstract Background and Aims Truncating variants in the TTN gene (TTNtv) are the most common genetic cause of dilated cardiomyopathy (DCM) but also occur as incidental findings in the general population. This study investigated factors associated with the clinical manifestation of TTNtv. Methods An international multicentre retrospective observational study was performed in families with TTNtv-related DCM. Shared frailty models were used to estimate associations of variant characteristics with lifetime risk of DCM, and logistic regression to estimate odds ratios (ORs) for individual-level clinical risk factor profiles (cardiac conditions, cardiovascular comorbidities, lifestyle) and DCM. Results A total of 3158 subjects in 1043 families with TTNtv-related DCM were studied. TTNtv-positive subjects were 21-fold more likely to develop DCM [OR, 21.21; 95% confidence interval (CI), 14.80–30.39]. Disease onset was earlier in males, but was similar for TTNtv of different types and locations. The presence of clinical risk factors was associated with earlier DCM onset (OR, 3.41; 95% CI, 2.06–5.64), with a prior history of atrial fibrillation having a two-fold increased odds of DCM (OR, 2.05; 95% CI, 1.27–3.32). The prevalence of clinical risk factors increased with age; however, the strength of the DCM association was greatest for young-onset (<30 years) disease (OR, 4.75; 95% CI, 2.35–9.60). Administration of beta-adrenergic receptor or renin-angiotensin system-blocking drugs prior to overt DCM was associated with 87% reduced odds of DCM (OR, .13; 95% CI, .08–.23). Conclusions Disease onset in TTNtv-associated familial DCM is dependent on individual patient context and is potentially modifiable by risk factor management and prophylactic therapeutic intervention.

Introduction: Spontaneous coronary artery dissection (SCAD) is an understudied cause of acute myocardial infarction due to hematoma formation in coronary arteries primarily affecting women. It is not known to what extent SCAD is genetically distinct from other cardiovascular diseases, including atherosclerotic coronary artery disease (CAD). Methods and Results: Through a meta-analysis of 8 GWAS (1917 cases, 9292 controls of European ancestry), we identified 17 risk loci, including 12 new. Functional annotations pointed at enrichment in enhancer marks of arteries, specifically smooth muscle cells, and strong candidate genes, such as tissue factor gene ( F3 ) on Chr1 near rs1146473 (OR=1.32, P=5.8 х10 -9 ). F3 is novel for SCAD or any cardiovascular disease. The risk allele correlated with F3 lower expression in arteries, supporting a mechanism consistent with hematoma formation. Bayesian gene regulatory networks constructed from expression and genetics data indicated the extracellular matrix organization in arteries as the biological function where most prioritized genes clustered (e.g. COL4A1/A2, HTRA1, and TIMP3 ). Overall, we report substantial polygenicity for SCAD (LDSC: h 2 SNP = 0.71 ± 0.11) and shared genetics with several neurovascular diseases (e.g intracranial aneurysm). Intriguingly, for 6 loci, colocalization analyses showed that SCAD and CAD are likely to share the same causal variants but involve opposite risk alleles (e.g COL4A1/A2 ). In addition, a negative genetic correlation was found between SCAD and CAD (rg=-0.12; P=3.7х10 -3 ), including after conditioning on BP (mt-COJO: rg CAD/SBP =-0.19, P=4.6х10 -6 ). Mendelian randomization analyses indicated higher BP to associate with increased risk for SCAD (beta IVW-SBP =0.05, P=7.6х10 -6 , beta IVW-DBP =0.10, P=1.9х10 -6 ) and CAD (beta IVW-SBP =0.04, P=8.6х10 -49 ; DBP: beta IVW-DBP =0.06, P=1.6х10 -44 ) but not BMI, lipids, or type 2 diabetes, which we confirmed as genetic risk factors for CAD Conclusions: Our results set the stage for future investigation of novel biological pathways relevant to both SCAD and CAD and potential therapeutic and preventive strategies specifically targeting this ischemic disease predominantly affecting women.