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Background: Spontaneous coronary artery dissection (SCAD) causes acute coronary syndrome or sudden cardiac death due to a separation of arterial wall layers. The majority of patients with SCAD are females (>80%) with few to no traditional cardiovascular risk factors. Though the physiological mechanisms that predispose to SCAD are unknown, common triggers for SCAD events include sympathoexcitatory stimuli, such as mental and emotional stress. Additionally, studies report high prevalence of depression and anxiety among patients with SCAD. Our study aimed to investigate cardiovascular responses to mental stress in patients with SCAD. We hypothesized that patients with SCAD would have exaggerated cardiovascular responses to mental stress compared to healthy controls. Methods: Four female patients with SCAD were age-, and BMI-matched with 4 healthy females. Participants underwent 2 minutes of baseline quiet rest, a 5-minute Stroop Color Word Test to induce mental stress, followed by 2 minutes of recovery. Continuous beat-to-beat blood pressure (BP, finger photoplethysmography) and heart rate (HR, 3-lead ECG) were recorded. Venous occlusion plethysmography was used to measure forearm blood flow (FBF). Forearm vascular conductance (FVC) was calculated as FBF/mean BP×100. Data are presented as change from baseline (Δmean±SD). Group data were compared using independent samples t-tests. Results: Resting hemodynamic parameters (Systolic [SBP], Diastolic [DBP], and Mean BP [MBP], Pulse pressure [PP], and HR) and FVC were similar between groups. Patients with SCAD had greater increases in DBP (Δ12±5 vs. Δ1±5 mmHg, p=0.02) and PP (Δ5±3 vs. Δ-7±8 mmHg, p=0.04) during the last minute of mental stress test compared to controls. Although, there were no differences in the changes of SBP (Δ17±7 vs. Δ-1±13 mmHg, p=0.05), MBP (Δ13±6 vs. Δ3±8 mmHg, p=0.08), HR (Δ8±0 vs. Δ10±2 bpm, p=0.12), or FVC (Δ1.5±1.2 vs. Δ1.8±1.3 ml/min/100 mmHg, p=0.80) between groups. During the last minute of recovery, there were no differences in hemodynamic parameters (SBP: Δ6±9 vs. Δ-4±10 mmHg, p=0.23; DBP: Δ2±7 vs. Δ-3±2 mmHg, p=0.22; MBP: Δ3±7 vs. Δ-3±5 mmHg, p=0.22; PP: Δ4±5 vs. Δ-1±8 mmHg, p= 0.35; HR: Δ-1±3 vs. Δ0±3 bpm, p=0.64), or FVC (Δ1.3±1.7 vs. Δ0.5±0.3 ml/min/100 mmHg, p= 0.35) between groups. Conclusion: These preliminary data suggest that patients with SCAD have greater increases in DBP and PP in response to mental stress compared to healthy controls. These exaggerated pressor responses might have implications for the pathophysiology of SCAD. NIH K23 HL155506, T32 DK07352, K01 HL148144, UL1 TR0022377, and AHA 898649. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Background: Spontaneous coronary artery dissection (SCAD) causes acute coronary syndrome via the sudden separation between the coronary arterial wall layers and/or hematoma. The SCAD patient population is >80% female who typically have few or no traditional cardiovascular disease risk factors (e.g., obesity, hypertension). Risk of a recurrent SCAD is reported as high as 19% at 3 years after an initial SCAD. Mechanisms underlying SCAD (re)occurrence are unknown. Common triggers for SCAD include sympathoexcitatory stimuli, including heavy exercise and intense Valsalva-like activities. This study tested the hypothesis that SCAD patients exhibit greater neurocardiovascular responses (e.g., blood pressure, heart rate, muscle sympathetic nerve activity) to isometric handgrip and post-exercise ischemia compared to healthy females. Methods: Eight females with a history of SCAD (age: 56±6 yrs, BMI: 28±4 kg/m2) and 6 age- and BMI-matched healthy female controls (CON, age: 55±8 yrs, BMI: 26±5 kg/m2) participated. Continuous blood pressure (finger photoplethysmography) and heart rate (3-lead ECG) were measured during rest (1 minute), isometric handgrip at 30% maximal voluntary contraction (2 minutes), and post-exercise ischemia at 220 mmHg (2 minutes) to isolate the skeletal muscle metaboreflex. Muscle sympathetic nerve activity (MSNA, peroneal microneurography) was measured in a subset of participants (5 SCAD/4 CON). Data are presented as an absolute change from rest (mean±SD). Two-way independent t-tests were used for statistical analyses. Results: Resting mean blood pressure (SCAD: 96±8 vs CON: 91±9 mmHg, p=0.354), heart rate (SCAD: 56±11 vs CON: 59±10 bpm, p=0.666), and MSNA (SCAD: 50±19 vs CON: 43±32 bursts/100 heartbeats, p=0.697) were not different between groups. Relative to healthy controls, SCAD patients elicited greater increases in mean blood pressure during isometric handgrip (SCAD: Δ9±3 vs CON: Δ4±4 mmHg, p=0.034) and post-exercise ischemia (SCAD: Δ7±4 vs CON: Δ3±3 mmHg, p=0.046). There were no group differences regarding heart rate responses during isometric handgrip (SCAD: Δ3±4 vs CON: Δ4±4 bpm, p=0.359) and post-exercise ischemia (SCAD: Δ3±4 vs CON: Δ2±3 bpm, p=0.861). Responses in MSNA during isometric handgrip (SCAD: Δ12±8 vs CON: Δ9±8 bursts/100 heartbeats, p=0.536) and post-exercise ischemia (SCAD: Δ11±2 vs CON: Δ13±10 bursts/100 heartbeats, p=0.713) also were not different between groups. Conclusion: These preliminary data suggest that compared to healthy females, female patients who experienced a SCAD exhibit greater pressor, but not chronotropic or sympathetic, responses to isometric handgrip and post-exercise ischemia. Exaggerated pressor responses to these perturbations may be a potential risk factor for SCAD (re)occurrence. NIH K23 HL155506, NIH T32 DK07352, NIH K01 HL148144, NIH UL1 TR0022377, and AHA 898649. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Introduction: Spontaneous coronary artery dissection (SCAD) is a nonatherosclerotic cause of acute coronary syndrome. While most patients are managed conservatively, some patients may require percutaneous or surgical revascularization. Limited data exist on SCAD patients referred for coronary artery bypass graft (CABG) surgery. Hypothesis: Examine the clinical characteristics, management, and outcomes of SCAD patients referred for CABG. Methods: Retrospective study of patients enrolled in the Mayo Clinic SCAD Registry between 2010-2020 who underwent CABG during the initial management of acute SCAD episode. Results: Among the 81 patients with SCAD referred for CABG, 3 (4%) were men, mean age was 40.6 +/- 8.4 years; the majority were white (91%), and 24 (30%) had pregnancy-associated SCAD (P-SCAD). The most common presenting symptom was chest pain 80 (99%); 57 (70%) presented with ST elevation myocardial infarction (STEMI), and 21 (26%) presented with non-ST elevation MI. Multivessel dissection occurred in 40 (49%), left anterior descending artery (LAD) involvement occurred in 66 (81%) and left main (LM) in 32 (40%). Left ventricular ejection fraction was <50% in 40 patients (49%) at time of initial SCAD. The most common reasons for CABG were the presence of high-risk anatomy (56%), hemodynamic instability/active ischemia (7%), failed PCI (9%), and other/unknown (12%). Most patients received venous plus arterial bypass grafts 42 (52%), saphenous vein grafts in 20 (25%), and left internal mammary artery in 17 (21%). Screening for underlying arteriopathy was performed in 50 (62%) of whom 29 (36%) had fibromuscular dysplasia. Recurrent SCAD occurred in 10 (12%) after an average of 6.2 +/- 5 years after initial SCAD. Of those with recurrent SCAD, none required repeat surgical revascularization and 6 required percutaneous intervention (PCI). There were no deaths. Conclusions: Patients undergoing CABG for SCAD commonly present with STEMI, LM, or multivessel dissection, and failed percutaneous intervention attempts. In addition, CABG for P-SCAD was more frequent than expected and may relate to the increased prevalence of multivessel dissection. CABG was associated with low mortality, but recurrent SCAD may still occur.

Objective: To evaluate outcomes of acute spontaneous coronary artery dissection (SCAD) managed with percutaneous coronary intervention (PCI) or conservative therapy. Background: SCAD is a non-atherosclerotic acute coronary syndrome that typically affects young otherwise healthy females. Whether SCAD with normal vessel flow at presentation should be managed with PCI or conservative therapy remains unknown. Methods: We performed a retrospective study of patients after a first SCAD episode (n=142). We excluded those treated with fibrinolysis (n=12) or coronary artery bypass grafting (CABG, n=8). We evaluated in-hospital and late outcomes in three SCAD groups: Vessel occlusion at presentation treated with PCI (Occ-PCI, n=30); normal vessel flow treated with PCI (NF-PCI, n=34) and those managed conservatively (CON, n=58). Results: Overall mean age was 42+9 years, 91% were female and 41% presented with STEMI. Outcomes are shown in the table below. In Occ-PCI, technical failure occurred in 8/30 (27%), of whom 5 required emergency CABG with one in-hospital death. Comparing NF-PCI with CON, there were no differences in clinical characteristics. Technical failure occurred in 16/34 (47%) of NF-PCI due to failure to cross with wire/device (8/34) or final loss of flow (8/34). Emergency CABG was required in 5 (15%). In CON, 54/58 had an uneventful in-hospital course. Four (7%) exhibited early dissection progression of whom two received PCI and one CABG. Long-term rates of target vessel revascularization, but not recurrent SCAD, were higher in NF-PCI vs CON (26% vs 9%, p=0.02; 24% vs 14%, p=0.23). Conclusions: PCI for acute SCAD is associated with high rates of technical failure and adverse clinical outcomes. In SCAD with normal vessel flow, conservative management may be preferable, with close early observation due to a hazard of progression of dissection. These findings underscore the importance of tailoring therapy to etiology of coronary obstruction.

Introduction: Current dietary guidelines no longer recommend against egg consumption despite the high cholesterol content. However, considerable controversy remains on the relationship between high egg consumption and cardiovascular disease (CVD) risk. The objective of this systematic review and meta-analysis was to explore the association between egg consumption and CVD events. Methods: We systematically searched PubMed, Scopus, and the Cochrane Database of Systematic Reviews from database inception through April 2015 for observational studies with hazard ratio (HRs) or relative risks (RRs) and 95% confidence intervals (95% CI) that reported the association between egg consumption and CVD events which included coronary heart disease (CHD) and stroke. Data were extracted by one reviewer followed by independent screening and extraction of study characteristics and outcome data by two other reviewers. Conflicts were resolved through consensus. Random-effects meta-analyses were used to pool the hazard ratios or relative risks from the included studies. Subgroup analyses were performed to explore the potential sources of heterogeneity. The quality of the included studies and publication bias were assessed. Results: We identified 5 cross-sectional and 6 prospective studies with median follow-up of 13.1 years. A total of 301,339 individuals and 10,262 total CVD events were included with 7,225 CHD and 3,037 stroke cases. Compared to consumption of less than 1 egg/day, higher egg consumption was associated with an increased risk of CVD events (pooled HR, 1.43; 95% CI, 1.01-2.03; p=0.012; I 2 = 65.7% and pooled RR, 1.09; 95% CI, 0.89-1.34; p=0.145; I 2 = 41.4%). Conclusions: Our analysis suggests that higher consumption of eggs (more than 1 egg/day) may be associated with increased risk of cardiovascular disease. Large and diverse prospective community-based cohorts will be necessary to establish optimal dietary recommendations for public health.

Rare familial spontaneous coronary artery dissection (SCAD) kindreds implicate genetic disease predisposition and provide a unique opportunity for candidate gene discovery. Whole-genome sequencing was performed in fifteen probands with non-syndromic SCAD who had a relative with SCAD, eight of whom had a second relative with extra-coronary arteriopathy. Co-segregating variants and associated genes were prioritized by quantitative variant, gene, and disease-level metrics. Curated public databases were queried for functional relationships among encoded proteins. Fifty-four heterozygous coding variants in thirteen families co-segregated with disease and fulfilled primary filters of rarity, gene variation constraint, and predicted-deleterious protein effect. Secondary filters yielded 11 prioritized candidate genes in 12 families, with high arterial tissue expression (n = 7), high-confidence protein-level interactions with genes associated with SCAD previously (n = 10), and/or previous associations with connective tissue disorders and aortopathies (n = 3) or other vascular phenotypes in mice or humans (n = 11). High-confidence associations were identified among 10 familial SCAD candidate-gene-encoded proteins. A collagen-encoding gene was identified in five families, two with distinct variants in COL4A2. Familial SCAD is genetically heterogeneous, yet perturbations of extracellular matrix, cytoskeletal, and cell–cell adhesion proteins implicate common disease-susceptibility pathways. Incomplete penetrance and variable expression suggest genetic or environmental modifiers.

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.

A 68 year old female with hyperlipidemia and tobacco use presented with acute, substernal, chest pressure that occurred during yard work. She had no prior history of coronary artery disease or stable angina. Electrocardiograms (ECG) did not have ischemic changes but high sensitivity troponin was elevated at 285 ng/L and peaked at 1308 ng/L. Therapy was started for acute coronary syndrome and nitroglycerin drip for continued discomfort. Echocardiogram showed ejection fraction of 61% and akinesis of the infero-septum at the mid-ventricle. Coronary angiogram showed diffuse narrowing of the large first septal branch artery (S1) concerning for coronary intramural hematoma. No other significant coronary artery disease was present. Cardiac magnetic resonance (CMR) confirmed hypokinesis of the septum and subendocardial delayed enhancement in the interventricular septum at the mid ventricle suggestive of an isolated septal perforator infarct. She was conservatively managed and discharged 48 hours later. Four days later she had recurrent chest pressure and was re-admitted. Her ECG showed J-point elevation in the anteroseptal leads. Repeat coronary angiogram showed unchanged type 2 spontaneous coronary artery dissection of S1 and a small coronary cameral fistula between the distal septal branch and the right ventricle. The diagnosis of spontaneous coronary artery dissection of the first septal branch is rare and may be missed on angiogram. CMR in addition to invasive coronary angiography aides in the evaluation of this rare cause of acute myocardial infarction and changes clinical management decisions including observation time and evaluation for fibromuscular dysplasia.