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BACKGROUND: Myocardial infarction with nonobstructive coronary arteries (MINOCAs) and angina with nonobstructive coronary arteries (ANOCAs) present diagnostic and therapeutic challenges. We assessed the frequency of coronary microvascular disease (CMD) and its subtypes in MINOCA compared with ANOCA and evaluated long-term cardiovascular outcomes. METHODS: Patients with nonobstructive coronary arteries undergoing invasive coronary function testing from 2012 to 2022 were prospectively enrolled and retrospectively classified as MINOCA or ANOCA (reference group). Myocardial infarction due to atherothrombosis, myocarditis, and Takotsubo syndrome were excluded. Invasive provocation testing was performed. CMD was classified as endothelium-independent (coronary flow reserve <2.5 with adenosine) and endothelium-dependent (<50% increase in coronary blood flow with acetylcholine). Major adverse cardiovascular events (cardiac death, nonfatal myocardial infarction, heart failure hospitalization, urgent revascularization, stroke) were recorded over 8 years. RESULTS: Of 622 patients, 73 (12%) had MINOCA (69% female, median age 56 years) and 549 (88%) ANOCA (72% female, median age 53 years). CMD was common in both groups (71% versus 64%; P =0.271), while endothelium-independent CMD was more frequent in MINOCA (41% versus 21%; P <0.001). Over a median follow-up of 4.5 years, major adverse cardiovascular events occurred more often in MINOCA (40% versus 11%; adjusted hazard ratio, 2.4; P =0.001). CMD predicted higher major adverse cardiovascular events in both MINOCA (hazard ratio, 3.6 [95% CI, 1.1–12.0]; P =0.038) and ANOCA (hazard ratio, 7.9 [95% CI, 2.9–21.8]; P <0.001). CONCLUSIONS: CMD is common in both MINOCA and ANOCA. The higher prevalence of endothelium-independent CMD in MINOCA suggests a potential mechanistic role in infarction. Patients with MINOCA have a worse prognosis than ANOCA, particularly when CMD is present.

Background: Spontaneous coronary artery dissection (SCAD) is a common type of myocardial infarction in females under the age of 50 years, caused by sudden separation between the coronary arterial wall layers and/or hematoma. The SCAD patient population is mostly females (~80%) with few or no traditional cardiovascular disease risk factors (e.g., obesity, hypertension). Common triggers for SCAD include sympathoexcitatory stimuli, such as intense physical and emotional stress. This implicates the sympathetic nervous system in the pathophysiology of SCAD. Thus, we aimed to investigate sympathetic nervous system responses to mental stress in patients with a history of SCAD. We hypothesized that females with a history of SCAD exhibit a greater increase in muscle sympathetic nerve activity (MSNA) with acute exposure to mental stress compared to healthy females. Methods: Seven females with a history of SCAD (age: 48±9 yrs, BMI: 29±6 kg/m 2 ) and seven age- and BMI-matched healthy female controls (CON, age: 49±9 yrs, BMI: 26±6 kg/m 2 ) participated in the study (both p>0.05). MSNA was measured via peroneal microneurography during a 2-minute rest, a 5-minute Stroop Color Word Test aimed at inducing mental stress, and a 2-minute recovery. Heart rate (HR, 3-lead electrocardiography) and BP (finger photoplethysmography) were continuously recorded during each stage. Data are presented as an absolute change from rest (Δmean±SD). Two-way independent t-tests were used for statistical analyses. Results: Resting mean blood pressure (MBP, SCAD: 96±14 vs CON: 89±7 mmHg, p=0.27), heart rate (HR, SCAD: 56±11vs CON: 65±16 bpm, p=0.25), MSNA burst frequency (SCAD: 22±9 vs CON: 18±7 bursts/minute, p=0.40) and total MSNA (SCAD: 1135±471 vs CON: 951±245 au/min, p=0.41) were not different between the groups. During the Stroop Color Word Test, average changes in MBP (SCAD: Δ10±9 vs CON: Δ8±5 mmHg, p=0.67) and HR (SCAD: Δ11±7 vs CON: Δ14±5 bpm, p=0.35) were not different between the groups. Similarly, average changes in MBP (SCAD: Δ3±4 vs CON: Δ-2±5 mmHg, p=0.13) and HR (SCAD: Δ3±4 vs CON: Δ3±2 bpm, p=0.62) were not different during the recovery. Changes in MSNA burst frequency with the Stroop Color Word Test (SCAD: Δ1±7 vs CON: Δ6±7 bursts/minute, p=0.22) and recovery (SCAD: Δ0±5 vs CON: Δ4±4 bursts/minute, p=0.13) were not different between the groups. Total MSNA changes were also not different during the Stroop Color Word Test (SCAD: Δ267±335 vs CON: Δ606±432 au/min, p=0.15) and recovery (SCAD: Δ68±666 vs CON: Δ217±217 au/min, p=0.61) between the two groups. Conclusion: These preliminary data suggest that contrary to our hypothesis, sympathetic nervous system responses to acute mental stress exposure are not different between females with a history of SCAD and healthy females. Further investigation is needed to understand MSNA association with chronic stress exposure in females with a history of SCAD. Funding: NIH K23 HL155506 This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Background/Objective: It remains unknown whether patients with the more common forms of hypermobility carry an elevated risk for the development of intracranial/cervical artery abnormalities. The objective of this study was to determine the prevalence of unruptured intracranial aneurysms, spontaneous cervical artery dissections, and fibromuscular dysplasia in patients with hypermobile Ehlers–Danlos Syndrome (hEDS) and hypermobility spectrum disorders (HSD) who presented to an academic headache clinic. Methods: This is a retrospective cohort study. We used an electronic medical record to look for all patients seen at the Mayo Clinic Florida Headache Center and EDS Clinic between 2019 and 2025 with a diagnosis of hEDS or HSD and neuroimaging of both the intracranial and cervical arteries. Results: There were 103 patients who met the inclusion criteria. There was no statistically significant difference between hEDS and HSD patients in developing cerebral/cervical arterial anomalies. Of the sample, 95% of the hypermobile patients with abnormal neuroimaging also had migraine. A total of eleven (10.7%) patients (hEDS + HSD) were diagnosed with unruptured intracranial aneurysms. Trends included age less than 50 years, small aneurysms in the anterior circulation, and having migraine with aura. Five (4.8%) patients were diagnosed with spontaneous cervical artery dissection with trends for HSD, over the age of 50 years, vertebral artery involvement and a history of migraine without aura. Six (5.8%) patients were diagnosed with fibromuscular dysplasia with trends for HSD, over the age of 50 years, carotid artery involvement and a history of migraine with aura. Conclusions: This is the first study to identify that patients with the more common type of EDS, HSD and hEDS, and a possible concomitant history of migraine have a heightened risk for the development of unruptured intracranial aneurysms, spontaneous cervical artery dissections, and fibromuscular dysplasia. Our findings suggest the need for targeted screening with intracranial and extracranial arterial imaging for this unique patient population.

Purpose. Spontaneous coronary artery dissection (SCAD) has emerged as an important cause of acute coronary syndrome predominantly affecting women. Although the knowledge of SCAD has expanded over the past 2 decades, limited evidence exists to guide post-event management and prevention of future adverse events. This review aims to synthesize the current understanding of SCAD and outline considerations for exercise prescription and cardiac rehabilitation (CR) in this unique population. Review Methods. A comprehensive literature review was conducted, incorporating original research articles, systematic reviews, meta-analyses, and current clinical guidelines related to SCAD and CR. Summary. Current literature demonstrates that CR is safe in this population and is associated with improvement in measures of physical and mental health. Expert consensus supports reintroduction of exercise and an individualized multidisciplinary CR framework.This review highlights current evidence and expert recommendations for the multidisciplinary outpatient management of patients with SCAD.

Background: Spontaneous coronary artery dissection (SCAD) is an important cause of acute coronary syndrome in women. Although the role of sex-hormones in the pathogenesis of SCAD is unclear, menopausal hormone therapy (HT) after SCAD is generally dissuaded. This limits management options for women with menopausal symptoms, the burden of which among SCAD patients is unknown. Aims: To quantify the burden of menopausal symptoms among women with a history of SCAD. Methods: We surveyed 1617 participants in the Mayo Clinic SCAD "Virtual" Multi-Center Registry on the topic of menopausal symptoms. Among women who had completed key portions of the survey (N = 846), 666 were identified as being either peri or post-menopausal based on patient report. Results: Menopausal symptom prevalence was high in women with SCAD (Figure). Many women (45%) experienced weight changes in the prior 6 months, and most (75%) never used HT for their menopausal symptoms. Forty-five (6%) women experienced menopause at age 45 or younger, and five (1%) experienced menopause at 40 or younger. At the time of the survey, intravaginal estrogen (11.4%) was the most common HT used, while all other individual HT therapies were used by fewer than 5%. Conclusions: Peri- and postmenopausal women with SCAD experience a high burden of menopausal symptoms, and very few use HT outside of intravaginal estrogen. These findings highlight the need for further exploration of treatment strategies for women with menopausal symptoms following SCAD including assessment of benefits versus harms in the subset of women with premature menopause.

Background: Spontaneous coronary artery dissection (SCAD) is an acute separation of coronary artery wall layers that blocks blood flow to the heart and leads to acute coronary syndrome. Patients with SCAD are relatively young females (~40-50 years) who have few cardiovascular risk factors. Sympathoexcitatory stress often precedes SCAD events (i.e. intense physical and/or emotional stress), suggesting that patients with SCAD may have augmented hemodynamic responses to sympathoexcitatory stressors. As such, we aimed to evaluate hemodynamic responses to cold stress in females with a history of SCAD and females without a history of SCAD. We hypothesized that females with a history of SCAD would have augmented hemodynamic responses to cold stress relative to females without a history of SCAD. Methods: Females with a history of SCAD were matched to females without a history of SCAD for age and body mass index. Heart rate (electrocardiogram) and beat-to-beat blood pressure (finger photoplethysmography) were recorded and averaged during two minutes of resting baseline and the minute during the cold pressor test that produced the peak hemodynamic response. Delta (Δ) values of the hemodynamic parameters were calculated. Data are reported as mean ± SD. Unpaired t-tests were used to analyze demographics, anthropometrics, resting hemodynamics, and hemodynamic responses between females with a history of SCAD and females without a history of SCAD. Results: Age (50±9 vs 56±8 years) and body mass index (27±6 vs 24±3 kg/m 2 ) did not differ between females with a history of SCAD (n=20) and females without a history of SCAD (n=12, both p>0.05), respectively. Resting heart rate ([HR], 57±10 vs 59±11 bpm), systolic blood pressure ([SBP], 112±14 vs 110±13 mmHg), diastolic blood pressure ([DBP], 72±10 vs 72±9 mmHg), and mean arterial pressure ([MAP], 86±11 vs 85±9 mmHg) were not different between females with a history of SCAD and females without a history of SCAD, respectively (all p>0.05). Hemodynamic responses to cold stress (ΔHR, 6±5 vs 7±5 bpm; ΔSBP, 20±16 vs 18±7 mmHg; ΔDBP, 7±11 vs 11±6 mmHg; ΔMAP, 10±14 vs 13±5 mmHg; all p>0.05) were not different between females with a history of SCAD and females without a history of SCAD, respectively. Conclusion: Hemodynamic responses to cold stress were not different between females with a history of SCAD and females without a history of SCAD, indicating that an augmented pressor response to this stress is likely not a primary predisposing factor to a SCAD. However, it remains important to assess other forms of stress to inform future care and counseling of patients with history of SCAD. Funding: K23HL155506 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Introduction: Spontaneous coronary artery dissection (SCAD) is one of the most common causes of myocardial infarction in females under the age of 50 and peripartum females. Furthermore, approximately 10% of patients with a history of SCAD have recurrent SCAD within 5 years. In a subset of patients, SCAD events are preceded by sympathoexcitatory stimuli, such as emotional or physical stress. This implicates the sympathetic nervous system in the pathophysiology of SCAD. Thus, we aimed to investigate this relationship through measuring muscle sympathetic nerve activity (MSNA) and quantifying MSNA transduction into diastolic blood pressure (BP) in females with a history of SCAD compared to healthy female controls. We hypothesized that females with a history of SCAD would have both augmented MSNA and MSNA transduction at rest compared to their healthy counterparts. Methods: Females with a history of SCAD and healthy controls (HC) were recruited for the study. MSNA was continuously recorded using microneurography at the peroneal nerve during 10-minute supine rest. Heart rate (HR, 3-lead electrocardiography) and BP (finger photoplethysmography) were continuously recorded during this period. We plotted binned MSNA burst areas against diastolic BP, using linear regression analysis in MATLAB R2023a to quantify the transduction slope. We compared peak bins of transduction slopes between the two groups. Data are presented as mean±SD. Independent samples t-tests were performed for statistical analyses. Results: Seven females with a history of SCAD (49±11 years; BMI: 28.5±7 kg/m 2 ) and six controls (51±8 years; BMI: 26.2±6.3 kg/m 2 ) participated in the study (both p>0.05). Resting systolic BP (SCAD: 121±8 vs. HC: 122±15 mmHg), diastolic BP (SCAD: 78±9 vs. HC: 75±7 mmHg) and HR (SCAD: 59±13 vs. HC: 67±18 bpm) were not different between groups (all p >0.05). MSNA burst frequency (SCAD: 25±12 vs. HC: 27±7 bursts/minute), burst incidence (SCAD: 42±18 vs. HC: 46±15 bursts/100 heartbeats), and total MSNA (SCAD: 820±286 vs. HC: 1050±119 au/minute) did not differ between groups (all p >0.05). MSNA transduction at rest was not different between females with a history of SCAD and healthy controls (0.02±0.03 vs. 0.05±0.05 mmHg(%·s) -1 , p>0.05). Conclusions: These preliminary data suggest that resting MSNA and transduction do not differ between females with a history of SCAD and healthy controls, contrary to our hypothesis. Further investigation is needed to determine if this observation is preserved with exposure to sympathoexcitatory stimuli. Funding: NIH K23 HL155506, T32 DK07352, K01 HL148144, UL1 TR0022377, and AHA 898649 This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Introduction: Spontaneous coronary artery dissection (SCAD) is a poorly understood cause of acute coronary syndrome (ACS), predominantly affecting young women and frequently related to acute stressors. It has been suggested that stress induced cardiomyopathy can cause dissection via mechanical distortion of the vessel at wall-motion hinge points. Whether specific coronary anatomic configurations also predispose to distortion and hence SCAD remains unknown. Hypothesis: Patients with left anterior descending (LAD) SCAD have a higher frequency of a “wrap around” (type IV - perfuses >25% of the inferior wall) LAD. Methods: Coronary angiograms of patients in the Mayo Clinic SCAD Registry were reviewed. Patients from functional angiogram registry with similar characteristics were used as controls. Patients with an LAD SCAD were compared to patients who never had an LAD SCAD. For identifying predictors of LAD SCAD, patients who never had an LAD SCAD were compared to patients that had an LAD SCAD as a recurrent event, but not as the initial presentation. Results: A total of 456 patients with SCAD (46±6 years; 96% women) were included. The control group consisted of 178 patients (44±7 years, 97% women). Type IV LAD was more common in the SCAD cohort (Figure 1), and patients in the LAD SCAD group had a higher proportion of type IV LAD when compared to non-LAD SCAD (47.6% vs 23.0% p < 0.001). Bifurcation involvement was also more frequent (48.6 vs 25.8%, p <0.001). Individual predictors of an LAD SCAD during follow-up were diagnosis of hypertension, peripartum SCAD, involvement of a bifurcation and type IV LAD. After multivariate analysis, only bifurcation involvement (OR 2.49, p = 0.01) and type IV LAD (OR 2.26, p = 0.02) remained as predictors of LAD SCAD during follow-up. In patients in whom the PDA perfused the apex (LAD I and II), PDA was more likely to be involved by SCAD (OR 6.17, p<0.001). There were no other differences in coronary distribution after stratifying by LAD types. Conclusions: Type IV LAD variant is more common in patients with LAD SCAD. This finding suggests that coronary anatomic variants predispose to SCAD and lend further support to the mechanical distortion hypothesis.