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88 citation(s) found for "Abhiram, P".

Utilization of Palliative Care for Cardiogenic Shock Complicating Acute Myocardial Infarction: A 15‐Year National Perspective on Trends, Disparities, Predictors, and Outcomes
Vallabhajosyula, Saraschandra , Prasad, Abhiram , Murphree, Dennis H. , Ingram, Cory , Mueller, Paul S. , Holmes, David R. , Barsness, Gregory W. , Dunlay, Shannon M. , Vallabhajosyula, Saraschandra , Prasad, Abhiram , Gersh, Bernard J.

Journal of the American Heart Association | July 18, 2019 | Volume: 8 | Issue: 15 | Pages: No page available

10.1161/jaha.119.011954 | PMID 31315497 Get It

Background This study sought to evaluate the 15‐year national utilization, trends, predictors, disparities, and outcomes of palliative care services ( PCS ) use in cardiogenic shock complicating acute myocardial infarction. Methods and Results A retrospective cohort from January 1, 2000 through December 31, 2014 was analyzed using the National Inpatient Sample database. Administrative codes for acute myocardial infarction–cardiogenic shock and PCS were used to identify eligible admissions. The primary outcomes were the frequency, utilization trends, and predictors of PCS . Secondary outcomes included in‐hospital mortality and resources utilization. Multivariable regression and propensity‐matching analyses were used to control for confounding. In this 15‐year period, there were 444 253 acute myocardial infarction–cardiogenic shock admissions, of which 4.5% received PCS . The cohort receiving PCS was older, of white race, female sex, and with higher comorbidity and acute organ failure. The PCS cohort received fewer cardiac procedures, but more noncardiac organ support therapies. Older age, female sex, white race, higher comorbidity, higher socioeconomic status, admission to a larger hospital, and admission after 2008 were independent predictors of PCS use. Use of PCS was independently associated with higher in‐hospital mortality (odds ratio 6.59 [95% CI 6.37–6.83]; P <0.001). The cohort with PCS use had >2‐fold higher in‐hospital mortality, 12‐fold higher use of do‐not‐resuscitate status, lesser in‐hospital resource utilization, and fewer discharges to home. Similar findings were observed in the propensity‐matched cohort. Conclusions PCS use in patients with acute myocardial infarction–cardiogenic shock is low, though there is a trend towards increased adoption. There are significant patient and hospital‐specific disparities in the utilization of PCS .
Clinical Features and Outcomes of Patients With Malignancy and Takotsubo Syndrome: Observations From the International Takotsubo Registry
Cammann, Victoria L. , Sarcon, Annahita, Ding, Katharina J., Kato, Ken , Vece, Davide Di , Szawan, Konrad A. , Gili, Sebastiano , Jurisic, Stjepan , Bacchi, Beatrice , Micek, Jozef, Frangieh, Antonio H. , Napp, L. Christian , Bossone, Eduardo , Citro, Rodolfo , Franke, Jennifer , Knorr, Maike, Heiner, Susanne, Burgdorf, Christof , Köenig, Wolfgang , Tschöpe, Carsten , Rajan, Lawrence, Michels, Guido, Pfister, Roman , Cuneo, Alessandro , Jacobshagen, Claudius, Karakas, Mahir , Banning, Adrian , Cuculi, Florim , Kobza, Richard , Fischer, Thomas, Vasankari, Tuija , Airaksinen, Juhani , Dworakowski, Rafał , Osswald, Stefan , Galiuto, Leonarda , Dichtl, Wolfgang , Delmas, Clément , Horowitz, John D. , Kozel, Martin , Widimský, Petr, Winchester, David E. , Gilyarova, Ekaterina, Gilyarov, Mikhail , El‐Battrawy, Ibrahim , Akın, İbrahim , Ukena, Christian , Pieske, Burkert , Rottbauer, Wolfgang , Opolski, Grzegorz , MacCarthy, Philip , Felix, Stephan B. , Borggrefe, Martin , Crea, Filippo , Katus, Hugo A. , Münzel, Thomas , Böhm, Michael , Prasad, Abhiram , Shinbane, Jerold S., Lüscher, Thomas F. , Ghadri, Jelena R. , Templin, Christian , Gilyarov, Mikhail , Bossone, Eduardo , Citro, Rodolfo , El-Battrawy, Ibrahim , Prasad, Abhiram , Tschöpe, Carsten , Koenig, Wolfgang , Banning, Adrian , Kobza, Richard , Gilyarov, Mikhail , Ukena, Christian , Seifert, Burkhardt , Jaguszewski, Miłosz , D’Ascenzo, Fabrizio , Noutsias, Michel , Thiele, Hölger , Kaiser, Christoph A. , Lairez, Olivier , Toušek, Petr , Shilova, Alexandra S. , Bauersachs, Johann , Hasenfuß, Gerd , Braun-Dullaeus, Ruediger Christian , Mario, Carlo Di , Schunkert, Heribert , Bax, Jeroen J. , Ruschitzka, Frank T.

Journal of the American Heart Association | July 17, 2019 | Volume: 8 | Issue: 15 | Pages: No page available

10.1161/jaha.118.010881 | PMID 31311438 Get It

Background Clinical characteristics and outcomes of takotsubo syndrome ( TTS ) patients with malignancy have not been fully elucidated. This study sought to explore differences in clinical characteristics and to investigate short‐ and long‐term outcomes in TTS patients with or without malignancy. Methods and Results TTS patients were enrolled from the International Takotsubo Registry. The TTS cohort was divided into patients with and without malignancy to investigate differences in clinical characteristics and to assess short‐ and long‐term mortality. A subanalysis was performed comparing long‐term mortality between a subset of TTS patients with or without malignancy and acute coronary syndrome (ACS) patients with or without malignancy. Malignancy was observed in 16.6% of 1604 TTS patients. Patients with malignancy were older and more likely to have physical triggers, but less likely to have emotional triggers compared with those without malignancy. Long‐term mortality was higher in patients with malignancy ( P <0.001), while short‐term outcome was comparable ( P =0.17). In a subanalysis, long‐term mortality was comparable between TTS patients with malignancies and ACS patients with malignancies ( P =0.13). Malignancy emerged as an independent predictor of long‐term mortality. Conclusions A substantial number of TTS patients show an association with malignancy. History of malignancy might increase the risk for TTS , and therefore, appropriate screening for malignancy should be considered in these patients. Clinical Trial Registration URL : http://www.clinicaltrial.gov . Unique identifier: NCT 01947621.
Cardiac arrest in takotsubo syndrome: results from the InterTAK Registry
Gili, Sebastiano , Cammann, Victoria L. , Schlossbauer, Susanne Anna, Kato, Ken , Vece, Davide Di , Jurisic, Stjepan , Micek, Jozef, Obeid, Slayman , Bacchi, Beatrice , Szawan, Konrad A. , Famos, F , Sarcon, Annahita, Levinson, Rena A. , Ding, Katharina J., Bossone, Eduardo , Citro, Rodolfo , Franke, Jennifer , Napp, L. Christian , Münzel, Thomas , Knorr, Maike, Heiner, Susanne, Katus, Hugo A. , Burgdorf, Christof , Tschöpe, Carsten , Pieske, Burkert , Rajan, Lawrence, Michels, Guido, Pfister, Roman , Cuneo, Alessandro , Jacobshagen, Claudius, Karakas, Mahir , Köenig, Wolfgang , Rottbauer, Wolfgang , Said, Samir M., Banning, Adrian , Cuculi, Florim , Kobza, Richard , Fischer, Thomas, Vasankari, Tuija , Airaksinen, Juhani , Opolski, Grzegorz , Dworakowski, Rafał , MacCarthy, Philip , Osswald, Stefan , Galiuto, Leonarda , Dichtl, Wolfgang , Empen, Klaus , Felix, Stephan B. , Delmas, Clément , El‐Battrawy, Ibrahim , Akın, İbrahim , Borggrefe, Martin , Gilyarova, Ekaterina, Gilyarov, Mikhail , Horowitz, John D. , Kozel, Martin , Widimský, Petr , Winchester, David E. , Ukena, Christian , Wischnewsky, Manfred , Prasad, Abhiram , Böhm, Michael , Lüscher, Thomas F. , Ghadri, Jelena R. , Templin, Christian , Gilyarov, Mikhail , Bossone, Eduardo , Citro, Rodolfo , El-Battrawy, Ibrahim , Prasad, Abhiram , Tschöpe, Carsten , Koenig, Wolfgang , Banning, Adrian , Kobza, Richard , Gilyarov, Mikhail , Ukena, Christian , D’Ascenzo, Fabrizio , Seifert, Burkhardt , Lenoir, Olivia , Jaguszewski, Miłosz , Noutsias, Michel , Schunkert, Heribert , Thiele, Hölger , Bauersachs, Johann , Hasenfuß, Gerd , Braun-Dullaeus, Ruediger Christian , Kaiser, Christoph A. , Crea, Filippo , Lairez, Olivier , Shilova, Alexandra S. , Toušek, Petr , Gaïta, Fiorenzo , Mario, Carlo Di , Bax, Jeroen J. , Ruschitzka, Frank T.

European Heart Journal | March 12, 2019 | Volume: 40 | Issue: 26 | Pages: 2142-2151

10.1093/eurheartj/ehz170 | PMID 31098611 Get It

Abstract Aims We aimed to evaluate the frequency, clinical features, and prognostic implications of cardiac arrest (CA) in takotsubo syndrome (TTS). Methods and results We reviewed the records of patients with CA and known heart rhythm from the International Takotsubo Registry. The main outcomes were 60-day and 5-year mortality. In addition, predictors of mortality and predictors of CA during the acute TTS phase were assessed. Of 2098 patients, 103 patients with CA and known heart rhythm during CA were included. Compared with patients without CA, CA patients were more likely to be younger, male, and have apical TTS, atrial fibrillation (AF), neurologic comorbidities, physical triggers, and longer corrected QT-interval and lower left ventricular ejection fraction on admission. In all, 57.1% of patients with CA at admission had ventricular fibrillation/tachycardia, while 73.7% of patients with CA in the acute phase had asystole/pulseless electrical activity. Patients with CA showed higher 60-day (40.3% vs. 4.0%, P &lt; 0.001) and 5-year mortality (68.9% vs. 16.7%, P &lt; 0.001) than patients without CA. T-wave inversion and intracranial haemorrhage were independently associated with higher 60-day mortality after CA, whereas female gender was associated with lower 60-day mortality. In the acute phase, CA occurred less frequently in females and more frequently in patients with AF, ST-segment elevation, and higher C-reactive protein on admission. Conclusions Cardiac arrest is relatively frequent in TTS and is associated with higher short- and long-term mortality. Clinical and electrocardiographic parameters independently predicted mortality after CA.
Coronary endothelial function testing may improve long-term quality of life in subjects with microvascular coronary endothelial dysfunction
Reriani, Martin, Flammer, Andreas J. , Duhé, Jessica, Gulati, Rajiv , Rihal, Charanjit S. , Lennon, Ryan J. , Tilford, Jonella M., Prasad, Abhiram , Lerman, Lilach O. , Lennon, Ryan, Prasad, Abhiram , Li, Jing , Rihal, Charanjit S. , Lerman, Amir

Open Heart | February 2, 2019 | Volume: 6 | Issue: 1 | Pages: e000870

10.1136/openhrt-2018-000870 | PMID 30815267 Get It

Aim Angina pectoris in the absence of obstructive coronary artery disease (CAD) is common and is associated with poor quality of life (QOL). Coronary microvascular endothelial dysfunction is associated with myocardial ischaemia and is a common cause of angina. We hypothesise that evaluation of coronary endothelial function, its diagnosis and treatment will favourably impact QOL in patients with angina symptoms and non-obstructive CAD. Methods and results Follow-up was done on 457 patients with chest pain and non-obstructive coronary arteries who had undergone coronary vascular reactivity evaluation by administration of intracoronary acetylcholine at the time of diagnostic study. After a mean follow-up of 8.4±4.7 years, QOL was assessed by administration of the SF-36 QOL survey. Patients diagnosed and treated for microvascular endothelial dysfunction had a higher (better) overall mental composite score (44.8 vs 40.9, p=0.036) and mental health score (44.2 vs 40.7, p=0.047), and a trend towards higher vitality scores (39.1 vs 35.9, p=0.053) and role emotional scores (43.6 vs 40.4, p=0.073), compared with patients with normal endothelial function. Conclusion Among patients with chest pain and normal coronaries, diagnosis and treatment of coronary microvascular endothelial dysfunction in those with angina pectoris and non-obstructive CAD are associated with better QOL compared with patients with normal endothelial function.
Outcomes Associated With Cardiogenic Shock in Takotsubo Syndrome
Vece, Davide Di , Citro, Rodolfo , Cammann, Victoria L. , Kato, Ken , Gili, Sebastiano , Szawan, Konrad A. , Micek, Jozef, Jurisic, Stjepan , Ding, Katharina J., Bacchi, Beatrice , Schwyzer, Moritz , Candreva, Alessandro , Bossone, Eduardo , Sarcon, Annahita, Franke, Jennifer , Napp, L. Christian , Münzel, Thomas , Knorr, Maike, Heiner, Susanne, Katus, Hugo A. , Burgdorf, Christof , Tschöpe, Carsten , Pieske, Burkert , Rajan, Lawrence, Michels, Guido, Pfister, Roman , Jacobshagen, Claudius, Hasenfuβ, Gerd, Karakas, Mahir , Köenig, Wolfgang , Rottbauer, Wolfgang , Said, Samir M., Banning, Adrian , Cuculi, Florim , Kobza, Richard , Fischer, Thomas, Vasankari, Tuija , Airaksinen, Juhani , Dworakowski, Rafał , MacCarthy, Philip , Osswald, Stefan , Galiuto, Leonarda , Dichtl, Wolfgang , Empen, Klaus , Felix, Stephan B. , Delmas, Clément , El‐Battrawy, Ibrahim , Akın, İbrahim , Borggrefe, Martin, Gilyarova, Ekaterina, Gilyarov, Mikhail , Horowitz, John D. , Kozel, Martin , Widimský, Petr , Winchester, David E. , Ukena, Christian , Prasad, Abhiram , Böhm, Michael , Lüscher, Thomas F. , Ghadri, Jelena R. , Templin, Christian , Gilyarov, Mikhail , Bossone, Eduardo , Citro, Rodolfo , El-Battrawy, Ibrahim , Prasad, Abhiram , Tschöpe, Carsten , Koenig, Wolfgang , Banning, Adrian , Kobza, Richard , Gilyarov, Mikhail , Ukena, Christian , D’Ascenzo, Fabrizio , Jaguszewski, Miłosz , Noutsias, Michel , Schunkert, Heribert , Thiele, Hölger , Bauersachs, Johann , Cuneo, Alessandro , Braun-Dullaeus, Ruediger Christian , Opolski, Grzegorz , Kaiser, Christoph A. , Crea, Filippo , Lairez, Olivier , Shilova, Alexandra S. , Toušek, Petr , Mario, Carlo Di , Bax, Jeroen J. , Ruschitzka, Frank T.

Circulation | January 14, 2019 | Volume: 139 | Issue: 3 | Pages: 413-415

10.1161/circulationaha.118.036164 | PMID 30586690 Get It

Temporary Mechanical Circulatory Support for Refractory Cardiogenic Shock Before Left Ventricular Assist Device Surgery
Vallabhajosyula, Saraschandra , Arora, Shilpkumar , Lahewala, Sopan , Kumar, Varun , Shantha, Ghanshyam Palamaner Subash , Stulak, John M., Gulati, Rajiv , Rihal, Charanjit S. , Prasad, Abhiram , Deshmukh, Abhishek , Vallabhajosyula, Saraschandra , Prasad, Abhiram , Jentzer, Jacob C. , Gersh, Bernard J. , Rihal, Charanjit S.

Journal of the American Heart Association | December 16, 2018 | Volume: 7 | Issue: 22 | Pages: No page available

10.1161/jaha.118.010193 | PMID 30571481 Get It

Background There are limited data on the role of temporary mechanical circulatory support ( MCS ) devices for cardiogenic shock before left ventricular assist device ( LVAD ) surgery. This study sought to evaluate the trends of use and outcomes of MCS in cardiogenic shock before LVAD surgery. Methods and Results This was a retrospective cohort study from 2005 to 2014 using the National Inpatient Sample (20% stratified sample of US hospitals). This study identified admissions undergoing LVAD surgery with preoperative cardiogenic shock. Admissions for other cardiac surgery and heart transplant were excluded. Temporary MCS was identified using administrative codes. The primary outcome was hospital mortality and secondary outcomes were hospital costs and lengths of stay in admissions with and without MCS use. In this 10‐year period, 9753 admissions were identified with 40.6% requiring pre‐ LVAD MCS . There was a temporal increase in the frequency of cardiogenic shock associated with an increase in non–intra‐aortic balloon pump MCS devices. The cohort receiving MCS had greater in‐hospital myocardial infarction, ventricular arrhythmias, and use of coronary angiography. On multivariable analysis, older age, myocardial infarction, and need for MCS devices were independently predictive of higher in‐hospital mortality. In 696 propensity‐matched pairs, use of MCS was predictive of higher in‐hospital mortality (odds ratio 1.4 [95% confidence interval 1.1–1.6]; P =0.02) and higher hospital costs, but similar lengths of stay. Conclusions In patients with cardiogenic shock bridged to LVAD therapy, there was a steady increase in preoperative MCS use. Use of MCS identified patients at higher risk for in‐hospital mortality and greater resource utilization.
Rare recurrence of apical ballooning (takotsubo) syndrome in an elderly man
Adigun, Rosalyn , Morley, Samantha , Prasad, Abhiram , Prasad, Abhiram

BMJ Case Reports | October 25, 2018 | Volume: 2018 | Issue: No issue available | Pages: bcr-2017-222451

10.1136/bcr-2017-222451 | PMID 30361448 Get It

Apical ballooning syndrome (ABS) is an under recognised clinical entity characterised by acute reversible left ventricular systolic dysfunction that mimics acute myocardial infarction in the absence of obstructive coronary artery disease; typically occurring in the setting of profound stress.1 ABS disproportionately affects older women and recurrences are infrequent. We, hereby, describe a rare phenomenon of recurrent ABS in an elderly male patient, 10 years apart, presenting with the same left ventricular morphological appearance following non-cardiac surgeries. The case illustrates the importance of considering ABS in the differential diagnosis of perioperative acute myocardial infarction in older men undergoing major surgery.
Tako‐Tsubo Cardiomyopathy in Severe Sepsis: Nationwide Trends, Predictors, and Outcomes
Vallabhajosyula, Saraschandra , Deshmukh, Abhishek , Prasad, Abhiram , Sakhuja, Ankit , Vallabhajosyula, Saraschandra , Prasad, Abhiram , Kashani, Kianoush

Journal of the American Heart Association | September 16, 2018 | Volume: 7 | Issue: 18 | Pages: No page available

10.1161/jaha.118.009160 | PMID 30371194 Get It

Background There are limited data on the presentation of Takotsubo cardiomyopathy ( TTC ) in severe sepsis. Methods and Results This was a retrospective cohort study using the National Inpatient Sample database (2007–2013) of all adults with severe sepsis. TTC was identified in patients with severe sepsis using previously validated administrative codes. The primary outcome was in‐hospital mortality, and secondary outcomes included resource utilization and discharge disposition. Regression analysis was performed for the entire cohort and a propensity‐matched sample. An exploratory analysis was performed for predictors of TTC incidence and mortality in TTC . During this 7‐year period, in 7.1‐million hospitalizations for severe sepsis, TTC was diagnosed in 10 746 (0.15%) admissions. TTC was noted more commonly in whites, females, and among 65‐ to 79‐year‐old individuals. TTC was independently associated with lower in‐hospital mortality in severe sepsis (odds ratio, 0.58; 95% confidence interval, 0.51–0.65). This association was more prominent in females (odds ratio, 0.51; 95% confidence interval, 0.44–0.59]) compared with males (odds ratio, 0.69; 95% confidence interval, 0.55–0.85]). Presentation in later years of the study period, middle‐age, female sex, and white race were independent predictors for the diagnosis of TTC . Age ≥80 years, black race, greater comorbidity, and multiorgan dysfunction were independently associated with higher in‐hospital mortality among TTC admissions. Conclusions TTC is observed with increasing frequency in severe sepsis and was associated with a significantly lower in‐hospital mortality compared with patients without TTC . Presentation in later years of the study period, middle age, female sex, and white race were independent predictors for the diagnosis of TTC in severe sepsis.
Local Production of Soluble Urokinase Plasminogen Activator Receptor and Plasminogen Activator Inhibitor‐1 in the Coronary Circulation Is Associated With Coronary Endothelial Dysfunction in Humans
Prasad, Abhiram , Nesbitt, Lisa, Loeffler, Darrell , Herrmann, Joerg, Lerman, Lilach O. , Prasad, Abhiram , Corban, Michel , Herrmann, Joerg, Lerman, Amir

Journal of the American Heart Association | September 16, 2018 | Volume: 7 | Issue: 15 | Pages: No page available

10.1161/jaha.118.009881 | PMID 30371230 Get It

Background Soluble urokinase plasminogen activator receptor (su PAR ) is a proinflammatory biomarker associated with immune activation and fibrinolysis inhibition. Plasminogen activator inhibitor ( PAI ‐1) is associated with excessive fibrin accumulation, thrombus formation, and atherosclerosis. The relationship between cross‐coronary su PAR and PAI ‐1 production and endothelial dysfunction remains unknown. Methods and Results Seventy‐nine patients (age 53±10 years, 75% women) with angina and normal coronary arteries or mild coronary artery disease (<40% stenosis) on angiogram underwent acetylcholine assessment of epicardial endothelial dysfunction (mid–left anterior descending coronary artery diameter decrease >20% after acetylcholine) and mircovascular endothelial dysfunction (coronary blood flow change <50% after acetylcholine). Simultaneous left main and coronary sinus su PAR and PAI ‐1 levels were measured in each patient before acetylcholine administration, and cross‐coronary su PAR and PAI ‐1 production rates were calculated. Patients’ characteristics, except for age (51±10 versus 57±9, P =0.02), and resting coronary hemodynamics were not significantly different between patients with (26%) versus without (74%) epicardial endothelial dysfunction. Patients’ characteristics and resting coronary hemodynamics were not significantly different between those with (62%) and those without (38%) mircovascular endothelial dysfunction. Patients with mircovascular endothelial dysfunction demonstrated local coronary su PAR production versus su PAR extraction in patients with normal microvascular function (median 25.8 [interquartile range 121.6, −23.7] versus −12.7 [52.0, −74.8] ng/min, P =0.03). Patients with epicardial endothelial dysfunction had higher median coronary PAI ‐1 production rates compared with those with normal epicardial endothelial function (1224.7 [12 940.7, −1915.4] versus −187.4 [4444.7, −4535.8] ng/min, P =0.03). Conclusions su PAR is released in coronary circulation of patients with mircovascular endothelial dysfunction and extracted in those with normal microvascular function. Cross‐coronary PAI ‐1 release is higher in humans with epicardial endothelial dysfunction.
Coronary endothelial function and spontaneous coronary artery dissection
Waterbury, Thomas M. , Gulati, Rajiv , Tweet, Marysia S. , Hayes, Sharonne N. , Prasad, Abhiram , Lerman, Amir

European Heart Journal: Acute Cardiovascular Care | August 20, 2018 | Volume: 9 | Issue: 1 | Pages: 90-95

10.1177/2048872618795255 | PMID 30124050 Get It

Objectives: To investigate the role of endothelial function in patients with previous spontaneous coronary artery dissection. Background: Mechanisms underlying spontaneous coronary artery dissection, including a possible contribution from endothelial dysfunction, remain poorly understood. Methods: This was a single center, retrospective study of patients with a prior spontaneous coronary artery dissection episode who underwent invasive endothelial function testing in the cardiac catheterization laboratory for evaluation of recurrent chest pain. Coronary epicardial and microvascular responses to acetylcholine, adenosine, and nitroglycerine were assessed. Findings were compared to a reference group of normal controls ( n=232). Results: A total of 10 patients with prior angiographically confirmed spontaneous coronary artery dissection were referred for coronary endothelial function testing. The median coronary flow reserve was 2.8 (interquartile range (IQR) 2.3, 3.6). The median change in coronary diameter with acetylcholine was −0.9% (IQR −23.9, 4.2). The median increase in peak coronary blood flow following acetylcholine administration was 91.4% (IQR 9.1, 105.7), which was similar to the response observed in a reference group of patients (median age 51 years, 96% women) from our laboratory with normal microvascular responses to acetylcholine: 107.4% (IQR 75.5, 165.7; P=0.20). Four patients (40%) had an abnormal microvascular response to acetylcholine, with less than a 50% increase in coronary blood flow, and all but one patient had left anterior descending artery or multivessel spontaneous coronary artery dissection. Conclusion: Coronary epicardial and microvascular vasomotor dysfunction is not a predominant feature of spontaneous coronary artery dissection. Endothelial dysfunction is not implicated as the principal underlying mechanism.