Machine learning-based prediction of in-hospital death for patients with takotsubo syndrome: The InterTAK-ML model

AIMS

Takotsubo syndrome (TTS) is associated with a substantial rate of adverse events. We sought to design a machine learning (ML)-based model to predict the risk of in-hospital death and to perform a clustering of TTS patients to identify different risk profiles.

METHODS AND RESULTS

A ridge logistic regression-based ML model for predicting in-hospital death was developed on 3482 TTS patients from the International Takotsubo (InterTAK) Registry, randomly split in a train and an internal validation cohort (75% and 25% of the sample size, respectively) and evaluated in an external validation cohort (1037 patients). Thirty-one clinically relevant variables were included in the prediction model. Model performance represented the primary endpoint and was assessed according to area under the curve (AUC), sensitivity and specificity. As secondary endpoint, a K-medoids clustering algorithm was designed to stratify patients into phenotypic groups based on the 10 most relevant features emerging from the main model. The overall incidence of in-hospital death was 5.2%. The InterTAK-ML model showed an AUC of 0.89 (0.85-0.92), a sensitivity of 0.85 (0.78-0.95) and a specificity of 0.76 (0.74-0.79) in the internal validation cohort and an AUC of 0.82 (0.73-0.91), a sensitivity of 0.74 (0.61-0.87) and a specificity of 0.79 (0.77-0.81) in the external cohort for in-hospital death prediction. By exploiting the 10 variables showing the highest feature importance, TTS patients were clustered into six groups associated with different risks of in-hospital death (28.8% vs. 15.5% vs. 5.4% vs. 1.0.8% vs. 0.5%) which were consistent also in the external cohort.

CONCLUSION

A ML-based approach for the identification of TTS patients at risk of adverse short-term prognosis is feasible and effective. The InterTAK-ML model showed unprecedented discriminative capability for the prediction of in-hospital death.

Coronary "Microvascular Dysfunction": Evolving Understanding of Pathophysiology, Clinical Implications, and Potential Therapeutics

Until recently, it has been generally held that stable angina pectoris (SAP) primarily reflects the presence of epicardial coronary artery stenoses due to atheromatous plaque(s), while acute myocardial infarction (AMI) results from thrombus formation on ruptured plaques. This concept is now challenged, especially by results of the ORBITA and ISCHEMIA trials, which showed that angioplasty/stenting does not substantially relieve SAP symptoms or prevent AMI or death in such patients. These disappointing outcomes serve to redirect attention towards anomalies of small coronary physiology. Recent studies suggest that coronary microvasculature is often both structurally and physiologically abnormal irrespective of the presence or absence of large coronary artery stenoses. Structural remodelling of the coronary microvasculature appears to be induced primarily by inflammation initiated by mast cell, platelet, and neutrophil activation, leading to erosion of the endothelial glycocalyx. This leads to the disruption of laminar flow and the facilitation of endothelial platelet interaction. Glycocalyx shedding has been implicated in the pathophysiology of coronary artery spasm, cardiovascular ageing, AMI, and viral vasculitis. Physiological dysfunction is closely linked to structural remodelling and occurs in most patients with myocardial ischemia, irrespective of the presence or absence of large-vessel stenoses. Dysfunction includes the impairment of platelet and vascular responsiveness to autocidal coronary vasodilators, such as nitric oxide, prostacyclin, and hydrogen sulphide, and predisposes both to coronary vasoconstriction and to a propensity for microthrombus formation. These findings emphasise the need for new directions in medical therapeutics for patients with SAP, as well as a wide range of other cardiovascular disorders.

Association of Circulating Plasma Secreted Frizzled-Related Protein 5 (Sfrp5) Levels with Cardiac Function

Secreted frizzled-related protein 5 (SFRP5) is a novel anti-inflammatory adipokine that may play a role in cardiovascular development and disease. However, there is yet to be a comprehensive investigation into whether circulating SFRP5 can be a biomarker for cardiac function. Plasma SFRP5 levels were measured via ELISA in 262 patients admitted to a cardiology unit. Plasma SFRP5 levels were significantly lower in patients with a history of heart failure (HF), coronary artery disease (CAD), and atrial fibrillation (AF; p = 0.001). In univariate analyses, SFRP5 levels were also significantly positively correlated with left ventricular ejection fraction (LVEF) (r = 0.52, p < 0.001) and negatively correlated with E/E' (r = -0.30, p < 0.001). Patients with HF, CAD, low LVEF, low triglycerides, high CRP, and high eGFR were associated with lower SFRP5 levels independent of age, BMI, or diabetes after multivariate analysis (overall model r = 0.729, SE = 0.638). Our results show that low plasma SFRP5 levels are independently associated with the presence of HF, CAD, and, importantly, impaired LV function. These results suggest a potential role of SFRP5 as a biomarker, as well as a mediator of cardiac dysfunction independent of obesity and metabolic regulation.

Effects of Soluble Guanylate Cyclase Stimulators and Activators on Anti-Aggregatory Signalling in Patients with Coronary Artery Spasm

Impairment of the nitric oxide/soluble guanylate cyclase (NO)/sGC) signalling cascade is associated with many forms of cardiovascular disease, resulting not only in compromised vasodilatation but also loss of anti-aggregatory homeostasis. Myocardial ischaemia, heart failure, and atrial fibrillation are associated with moderate impairment of NO/sGC signalling, and we have recently demonstrated that coronary artery spasm (CAS) is engendered by severe impairment of platelet NO/sGC activity resulting in combined platelet and vascular endothelial damage. We therefore sought to determine whether sGC stimulators or activators might normalise NO/sGC homeostasis in platelets. ADP-induced platelet aggregation and its inhibition by the NO donor sodium nitroprusside (SNP), the sGC stimulator riociguat (RIO), and the sCG activator cinaciguat (CINA) alone or in addition to SNP were quantitated. Three groups of individuals were compared: normal subjects (n = 9), patients (Group 1) with myocardial ischaemia, heart failure and/or atrial fibrillation (n = 30), and patients (Group 2) in the chronic stage of CAS (n = 16). As expected, responses to SNP were impaired (p = 0.02) in patients versus normal subjects, with Group 2 patients most severely affected (p = 0.005). RIO alone exerted no anti-aggregatory effects but potentiated responses to SNP to a similar extent irrespective of baseline SNP response. CINA exerted only intrinsic anti-aggregatory effects, but the extent of these varied directly (r = 0.54; p = 0.0009) with individual responses to SNP. Thus, both RIO and CINA tend to normalise anti-aggregatory function in patients in whom NO/sGC signalling is impaired. The anti-aggregatory effects of RIO consist entirely of potentiation of NO, which is not selective of platelet NO resistance. However, the intrinsic anti-aggregatory effects of CINA are most marked in individuals with initially normal NO/sGC signalling, and thus their magnitude is at variance with extent of physiological impairment. These data suggest that RIO and other sGC stimulators should be evaluated for clinical utility in both prophylaxis and treatment of CAS.

'Bushfire Season' in Australia: Determinants of Increases in Risk of Acute Coronary Syndromes and Takotsubo Syndrome

BACKGROUND

Climate change has resulted in an increase in ambient temperatures during the summer months as well as an increase in risk of associated air pollution and of potentially disastrous bushfires throughout much of the world. The increasingly frequent combination of elevated summer temperatures and bushfires may be associated with acute increases in risks of cardiovascular events, but this relationship remains unstudied. We evaluated the individual and cumulative impacts of daily fluctuations in temperature, fine particulate matter of less than 2.5 µm (PM_2.5) pollution and presence of bushfires on incidence of acute coronary syndromes and Takotsubo syndrome.

METHODS

From November 1, 2019, to February 28, 2020, all admissions with acute coronary syndromes or Takotsubo syndrome to South Australian tertiary public hospitals were evaluated. Univariate and combined associations were sought among each of 1) maximal daily temperature, 2) PM_2.5 concentrations, and 3) presence of active bushfires within 200 km of the hospitals concerned.

RESULTS

A total of 504 patients with acute coronary syndromes and 35 with Takotsubo syndrome were studied. In isolation, increasing temperature was associated (r_s = 0.26, P = .005) with increased incidence of acute coronary syndromes, while there were similar, but nonsignificant correlations for PM_2.5 and presence of bushfires. Combinations of all these risk factors were also associated with a doubling of risk of acute coronary syndromes. No significant associations were found for Takotsubo syndrome.

CONCLUSION

The combination of high temperatures, presence of bushfires and associated elevation of atmospheric PM_2.5 concentrations represents a substantially increased risk for precipitation of acute coronary syndromes; this risk should be factored into health care planning including public education and acute hospital preparedness.

The Wider Considerations in Closing Chronic Disease Gaps - Focus on Heart Failure and Implementation

BACKGROUND

Heart failure (HF) is predominately a chronic disease. There are overlaps in HF and chronic disease research and care. Chronic disease and HF research are conducted with multiple goals. The overarching goal is "optimized patient outcomes at maximum costeffectiveness". However, observations on patients can come with many variables; thus, we see differences in clinical translation. This document discusses an argument for three important gaps common to HF and chronic disease, i.e., screening, self-management, and patient-reported outcomes (PRO), and provides a glance of how it could fit into the evidence tree. Pertinent arguments for a framework for health services and models of care are provided as a prelude to future consensus.

METHODOLOGY

1) A preliminary literature review to identify a taxonomy for cardiovascular research, and 2) a review of the published literature describing the translation of research studies into clinical practice for cardiovascular disorders. A spectrum from observational to large randomized controlled trials to post-marketing studies were identified.

DISCUSSION

A brief discussion on traditional research and differences focusing on screening, mixed methods research concepts, and chronic diseases models of care. Six steps to facilitate this: 1) Research design; 2) Research application (translation) i. routine ii. challenges; 3. Transforming research to translational level; 4. Funding and infrastructure; 5. Clinical Centres of Research Excellence (CCRE) and collaboration; 6. Governance and cost-effectiveness.

CONCLUSION

Implementation research that aims to link research findings to improved patient outcomes in an efficient and effective way is a neglected area. Skills required to perform implementation research are complex. Ways to maximize translational impacts for chronic disease research to clinical practice are described in a HF context.

Cardioprotective Actions of Nitroxyl Donor Angeli's Salt are Preserved in the Diabetic Heart and Vasculature in the Face of Nitric Oxide Resistance

Background and Purpose

The risk of fatal cardiovascular events is increased in patients with type 2 diabetes mellitus (T2DM). A major contributor to poor prognosis is impaired nitric oxide (NO•) signalling at the level of tissue responsiveness, termed NO• resistance. This study aimed to determine if T2DM promotes NO• resistance in the heart and vasculature and whether tissue responsiveness to nitroxyl (HNO) is affected.

Experimental Approach

At 8 weeks of age, male Sprague–Dawley rats commenced a high‐fat diet. After 2 weeks, the rats received low‐dose streptozotocin (two intraperitoneal injections, 35 mg·kg⁻¹, over two consecutive days) and continued on the same diet. Twelve weeks later, isolated hearts were Langendorff‐perfused to assess responses to the NO• donor diethylamine NONOate (DEA/NO) and the HNO donor Angeli's salt. Isolated mesenteric arteries were utilised to measure vascular responsiveness to the NO• donors sodium nitroprusside (SNP) and DEA/NO, and the HNO donor Angeli's salt.

Key Results

Inotropic, lusitropic and coronary vasodilator responses to DEA/NO were impaired in T2DM hearts, whereas responses to Angeli's salt were preserved or enhanced. Vasorelaxation to Angeli's salt was augmented in T2DM mesenteric arteries, which were hyporesponsive to the relaxant effects of SNP and DEA/NO.

Conclusion and Implications

This is the first evidence that inotropic and lusitropic responses are preserved, and NO• resistance in the coronary and mesenteric vasculature is circumvented, by the HNO donor Angeli's salt in T2DM. These findings highlight the cardiovascular therapeutic potential of HNO donors, especially in emergencies such as acute ischaemia or heart failure.

The Antianginal Drug Perhexiline Displays Cytotoxicity against Colorectal Cancer Cells In Vitro: A Potential for Drug Repurposing

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. Perhexiline, a prophylactic anti-anginal drug, has been reported to have anti-tumour effects both in vitro and in vivo. Perhexiline as used clinically is a 50:50 racemic mixture ((R)-P) of (-) and (+) enantiomers. It is not known if the enantiomers differ in terms of their effects on cancer. In this study, we examined the cytotoxic capacity of perhexiline and its enantiomers ((-)-P and (+)-P) on CRC cell lines, grown as monolayers or spheroids, and patient-derived organoids. Treatment of CRC cell lines with (R)-P, (-)-P or (+)-P reduced cell viability, with IC₅₀ values of ~4 µM. Treatment was associated with an increase in annexin V staining and caspase 3/7 activation, indicating apoptosis induction. Caspase 3/7 activation and loss of structural integrity were also observed in CRC cell lines grown as spheroids. Drug treatment at clinically relevant concentrations significantly reduced the viability of patient-derived CRC organoids. Given these in vitro findings, perhexiline, as a racemic mixture or its enantiomers, warrants further investigation as a repurposed drug for use in the management of CRC.

Contextualising evidence based medicine in determining the key root for translational effectiveness for chronic disease self-management and heart failure

BACKGROUND

Congestive heart failure (CHF) management has proven devastating on morbidity, mortality, quality of life and also costly to health systems. Therapeutics for CHF have advanced and benefited greatly due to large multicentre randomised controlled trials and the evidence obtained from them. Management for chronic diseases and nonpharmaceutical therapies such as chronic disease self-management has lagged, and for CHF the evidence base has even been questioned.

METHODS

Perspective and non systematic mini review.

CONCLUSIONS

Advancing translational research standards is important to achieve optimal cost effectiveness. Importantly is understanding evidence generation in medicine, identifying the primary roots for management and its translation.

Impairment of Anti-Aggregatory Responses to Nitric Oxide and Prostacyclin: Mechanisms and Clinical Implications in Cardiovascular Disease

The propensity towards platelet-rich thrombus formation increases substantially during normal ageing, and this trend is mediated by decreases in platelet responsiveness to the anti-aggregatory nitric oxide (NO) and prostacyclin (PGI₂) pathways. The impairment of soluble guanylate cyclase and adenylate cyclase-based signalling that is associated with oxidative stress represents the major mechanism of this loss of anti-aggregatory reactivity. Platelet desensitization to these autacoids represents an adverse prognostic marker in patients with ischemic heart disease and may contribute to increased thrombo-embolic risk in patients with heart failure. Patients with platelet resistance to PGI₂ also are unresponsive to ADP receptor antagonist therapy. Apart from ischemia, diabetes and aortic valve disease are also associated with impaired anti-aggregatory homeostasis. This review examines the association of impaired platelet cyclic nucleotide (i.e., cGMP and cAMP) signalling with the emerging evidence of thromboembolic risk in cardiovascular diseases, and discusses the potential therapeutic strategies targeting this abnormality.

Transdiagnostic Cognitive-Behavioral Therapy for Depression and Anxiety Disorders in Cardiovascular Disease Patients: Results From the CHAMPS Pilot-Feasibility Trial

OBJECTIVE

The aim of the Cardiovascular Health in Anxiety and Mood Problems Study (CHAMPS) is to pilot the Unified Protocol (UP) for the transdiagnostic treatment of depression and anxiety disorders in patients recently hospitalized for cardiovascular diseases (CVDs) and evaluate the feasibility.

METHODS

The present study is a controlled, block randomized pragmatic pilot-feasibility trial incorporating qualitative interview data, comparing UP (n = 9) with enhanced usual care (EUC, n = 10). Eligible trial participants had a recent CVD-cause admission and were above the severity threshold for depression or anxiety denoted by Patient Health Questionnaire (PHQ-9) total scores ≥10 and/or Generalized Anxiety Disorder (GAD-7) total scores ≥7 respectively on two occasions, and met criteria for one or more depression or anxiety disorders determined by structured clinical interview. Study outcomes were analyzed as intention-to-treat using linear mixed models and qualitative interview data were analyzed with content analysis.

RESULTS

Quantitative and qualitative measured indicated acceptability of the transdiagnostic CBT intervention for CVD patients with depression or anxiety disorders. Satisfaction with UP was comparable to antidepressant therapy and higher than general physician counseling. However, there were difficulties recruiting participants with current disorders and distress on two occasions. The UP was associated with a reduction in total number of disorders determined by blinded raters. Linear mixed models indicated that a significantly greater reduction in anxiety symptoms was evident in the UP group by comparison to the EUC group (GAD-7, p between groups = 0.011; Overall Anxiety Severity and Impairment Scale, p between groups = 0.013). Results favored the UP group by comparison to EUC for change over 6 months on measures of physical quality of life and harmful alcohol use. There was no difference between the two groups on changes in depression symptoms (PHQ-9), stress, metacognitive worry beliefs, physical activity, or adherence.

DISCUSSION

In conclusion, this feasibility trial indicates acceptability of transdiagnostic CBT intervention for CVD patients with depression or anxiety disorders that is tempered by difficulties with recruitment. Larger trials are required to clarify the efficacy of transdiagnostic depression and anxiety disorder CBT in populations with CVDs and depressive or anxiety disorders.

CLINICAL TRIAL REGISTRATION

https://www.australianclinicaltrials.gov.au/anzctr/trial/ACTRN12615000555550, identifier: ACTRN12615000555550.

The unspoken benefit of participation in a clinical trial

BACKGROUND

Publicly funded trials do not usually offer financial incentives to volunteers. An intensive level of medical care could act as an additional motivator for participation. Our aim was to establish whether patients may draw any clinical benefit from volunteering in a clinical trial.

METHODS

We analysed the recruitment process of a phase II randomised controlled trial, the Inorganic Nitrate in Angina Study.

RESULTS

Two-hundred and thirteen patients with a history of stable angina and who had been under at least annual primary care review were screened for participation by history taking, examination, 12-lead electrocardiography, treadmill test and echocardiography. Thirty-five (16.4%) patients were found to have significant unstable or new clinical pathology, requiring urgent clinical attention. We identified 17 (7.9%) patients with unstable angina. Furthermore, we found new undiagnosed pathologies: amyloidosis in two (0.9%), hypertrophic cardiomyopathy in two (0.9%), left ventricular systolic dysfunction (ejection fraction <45%) in three (1.4%), left ventricular thrombus in one (0.4%), significant valvular disease in five (2.4%) and arrhythmias in six (2.8%).

CONCLUSION

Compared with routine care, patients screened for a clinical trial may come under an increased level of scrutiny that may affect their clinical management. This may act as additional motivator to attract patients to future studies.

Angina due to coronary artery spasm (variant angina): diagnosis and intervention strategies

INTRODUCTION

Since Prinzmetal first described a 'variant' form of angina pectoris, with predominantly resting episodes of pain and cyclic severity variations, it has gradually become apparent that this clinical presentation is caused by episodes of coronary artery spasm (CAS) involving focal or diffuse changes in large and/or small coronary arteries in the presence or absence of 'fixed' coronary artery stenoses. However, most clinicians have only limited understanding of this group of disorders.

AREAS COVERED

We examine the clinical presentation of CAS, associated pathologies outside the coronary vasculature, impediments to making the diagnosis, provocative diagnostic tests, available and emerging treatments, and the current understanding of pathogenesis.

EXPERT OPINION

CAS is often debilitating and substantially under-diagnosed and occur mainly in women. Many patients presenting with CAS crises have non-diagnostic ECGs and normal serum troponin concentrations, but CAS can be suspected on the basis of history and association with migraine, Raynaud's phenomenon and Kounis syndrome. Definitive diagnosis requires provocative testing at coronary angiography. Treatment still centers around the use of calcium antagonists, but with greater understanding of pathogenesis, new management options are emerging.

Follistatin-like 3 (FSTL3) levels are increased in acute heart failure patients

Introduction

Follistatin-like 3 (FSTL3) is a secreted protein that has been suggested to play an important role in modulating cardiac remodeling and hypertrophy. In this study, we aim to determine whether: 1) FSTL3 is incrementally elevated in patients with HF vs those with other cardiovascular disease (CVD); and 2) increased FSTL3 is associated with 2 or more hospital admissions due to major adverse CV events (MACE) within 1 year.

Methods and results

We measured circulating levels of FSTL3 using commercially available ELISA (R&D systems) in a total of n=696 patients. FSTL3 levels were compared between: 1) healthy-aging volunteers with no prior major CVD (n=267, age 67±6 years) and 2) patients admitted to cardiology unit for various CVD (n=429, age 66±14 years); among those (n=178, age 68±13 years) had HF. Patients with HF had 2-fold higher FSTL3 levels vs healthy age-matched controls vs those with other CVD (p&lt;0.001). Occurrences of MACE were recorded up to 1 year for patients admitted to cardiology unit. On univariate analyses, patient with 2 or more MACE within 1 year (n=91, 27%) had significant elevated FSTL3 levels (P=0.003), is associated with older age (P&lt;0.005). On multivariate analysis, high FSTL3 levels (P=0.034) is an independent predictor of 2 or more MACE admissions within 1 year after adjusting for age, clinical comorbidities and medications.

Conclusions

FSTL3 is incrementally increased in patients with HF and is associated with poorer prognosis. Elevated FSTL3 levels is associated with increased risks of cardiac hospital readmissions for patients with multiple CV morbidities.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NSW Ministry of Health EMC Fellowship (Australia)

Randomized controlled trial of perhexiline on regression of left ventricular hypertrophy in patients with symptomatic hypertrophic cardiomyopathy (RESOLVE-HCM trial)

BACKGROUND

The presence and extent of left ventricular hypertrophy (LVH) is a major determinant of symptoms in patients with hypertrophic cardiomyopathy (HCM). There is increasing evidence to suggest that myocardial energetic impairment represents a central mechanism leading to LVH in HCM. There is currently a significant unmet need for disease-modifying therapy that regresses LVH in HCM patients. Perhexiline, a potent carnitine palmitoyl transferase-1 (CPT-1) inhibitor, improves myocardial energetics in HCM, and has the potential to reduce LVH in HCM.

OBJECTIVE

The primary objective is to evaluate the effects of perhexiline treatment on the extent of LVH, in symptomatic HCM patients with at least moderate LVH.

METHODS/DESIGN

RESOLVE-HCM is a prospective, multicenter double-blind placebo-controlled randomized trial enrolling symptomatic HCM patients with at least moderate LVH. Sixty patients will be randomized to receive either perhexiline or matching placebo. The primary endpoint is change in LVH, assessed utilizing cardiovascular magnetic resonance (CMR) imaging, after 12-months treatment with perhexiline.

SUMMARY

RESOLVE-HCM will provide novel information on the utility of perhexiline in regression of LVH in symptomatic HCM patients. A positive result would lead to the design of a Phase 3 clinical trial addressing long-term effects of perhexiline on risk of heart failure and mortality in HCM patients.

Abstract P405: Cardioprotective Actions Of Nitroxyl Donor Angeli's Salt Are Preserved In The Diabetic Heart And Vasculature In The Face Of Nitric Oxide Resistance

Introduction: The risk of fatal cardiovascular events is increased in patients with type 2 diabetes mellitus (T2DM). A major contributor to poor prognosis is impaired nitric oxide (NO•) signalling at the level of tissue responsiveness, termed NO• resistance. Nitroxyl (HNO) induces positive inotropic and lusitropic effects in healthy and failing hearts.

Hypothesis: We hypothesised that in a rodent model, T2DM will promote, and HNO will circumvent, NO• resistance in the myocardium and coronary vasculature.

Methods: At 8 weeks of age, male Sprague-Dawley rats commenced a high-fat diet. After two weeks, the rats received low-dose streptozotocin (two intraperitoneal injections, 35 mg/kg, over two consecutive days), and continued the diet. Twelve weeks later, hearts were Langendorff-perfused to assess responses to the NO• donor diethylamine NONOate (DEA/NO) and the HNO donor Angeli’s salt.

Results: Inotropic, lusitropic and coronary vasodilator responses to DEA/NO were impaired, and responses to Angeli’s salt were preserved or enhanced, in T2DM hearts compared with non-diabetic hearts.

Conclusions: This is the first evidence that inotropic and lusitropic responses are preserved, and NO• resistance in the coronary vasculature is circumvented, by the HNO donor Angeli’s salt in T2DM. These findings highlight the cardiovascular therapeutic potential of HNO donors, especially in cardiac emergencies such as acute ischaemia or heart failure.

Figure 1. Dose-response curves and maximal responses to DEA/NO or Angeli's salt in diabetic or non-diabetic hearts. (A-C) LV+dP/dt, (D-F) LV-dP/dt and (G-I) coronary flow rate. Data expressed as change from baseline (denoted by Δ), mean ± SEM. Data analysed by two-way RM ANOVA with Sidak's post-hoc test. *P<0.05 vs. non-diabetic. LV, left ventricular; LV+dP/dt, maximal rate of rise in LV pressure; LV-dP/dt, maximal rate of fall in LV pressure.

Impact of Atrial Fibrillation on Outcome in Takotsubo Syndrome: Data From the International Takotsubo Registry

Background

Atrial fibrillation (AF) is a major risk factor for mortality. The prevalence, clinical correlates, and prognostic impact of AF in Takotsubo syndrome (TTS) have not yet been investigated in a large patient cohort. This study aimed to investigate the prevalence, clinical correlates, and prognostic impact of AF in patients with TTS.

Methods and Results

Patients with TTS were enrolled from the International Takotsubo Registry, which is a multinational network with 26 participating centers in Europe and the United States. Patients were dichotomized according to the presence or absence of AF at the time of admission. Of 1584 patients with TTS, 112 (7.1%) had AF. The mean age was higher (P<0.001), and there were fewer women (P=0.046) in the AF than in the non‐AF group. Left ventricular ejection fraction was significantly lower (P=0.001), and cardiogenic shock was more often observed (P<0.001) in the AF group. Both in‐hospital (P<0.001) and long‐term mortality (P<0.001) were higher in the AF group. Multivariable Cox regression analysis revealed that AF was independently associated with higher long‐term mortality (hazard ratio, 2.31; 95% CI, 1.50–3.55; P<0.001). Among patients with AF on admission, 42% had no known history of AF before the acute TTS event, and such patients had comparable in‐hospital and long‐term outcomes compared with those with a history of AF.

Conclusions

In patients presenting with TTS, AF on admission is significantly associated with increased in‐hospital and long‐term mortality rates. Whether antiarrhythmics and/or cardioversion are beneficial in TTS with AF should thus be tested in a future trial.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01947621.

Coexistence and outcome of coronary artery disease in Takotsubo syndrome

AIMS

Takotsubo syndrome (TTS) is an acute heart failure syndrome, which shares many features with acute coronary syndrome (ACS). Although TTS was initially described with angiographically normal coronary arteries, smaller studies recently indicated a potential coexistence of coronary artery disease (CAD) in TTS patients. This study aimed to determine the coexistence, features, and prognostic role of CAD in a large cohort of patients with TTS.

METHODS AND RESULTS

Coronary anatomy and CAD were studied in patients diagnosed with TTS. Inclusion criteria were compliance with the International Takotsubo Diagnostic Criteria for TTS, and availability of original coronary angiographies with ventriculography performed during the acute phase. Exclusion criteria were missing views, poor quality of angiography loops, and angiography without ventriculography. A total of 1016 TTS patients were studied. Of those, 23.0% had obstructive CAD, 41.2% had non-obstructive CAD, and 35.7% had angiographically normal coronary arteries. A total of 47 patients (4.6%) underwent percutaneous coronary intervention, and 3 patients had acute and 8 had chronic coronary artery occlusion concomitant with TTS, respectively. The presence of CAD was associated with increased incidence of shock, ventilation, and death from any cause. After adjusting for confounders, the presence of obstructive CAD was associated with mortality at 30 days. Takotsubo syndrome patients with obstructive CAD were at comparable risk for shock and death and nearly at twice the risk for ventilation compared to an age- and sex-matched ACS cohort.

CONCLUSIONS

Coronary artery disease frequently coexists in TTS patients, presents with the whole spectrum of coronary pathology including acute coronary occlusion, and is associated with adverse outcome.

TRIAL REGISTRATION

ClinicalTrials.gov number: NCT01947621.

Prognostic impact of acute pulmonary triggers in patients with takotsubo syndrome: new insights from the International Takotsubo Registry

AIMS

Acute pulmonary disorders are known physical triggers of takotsubo syndrome (TTS). This study aimed to investigate prevalence of acute pulmonary triggers in patients with TTS and their impact on outcomes.

METHODS AND RESULTS

Patients with TTS were enrolled from the International Takotsubo Registry and screened for triggering factors and comorbidities. Patients were categorized into three groups (acute pulmonary trigger, chronic lung disease, and no lung disease) to compare clinical characteristics and outcomes. Of the 1670 included patients with TTS, 123 (7%) were identified with an acute pulmonary trigger, and 194 (12%) had a known history of chronic lung disease. The incidence of cardiogenic shock was highest in patients with an acute pulmonary trigger compared with those with chronic lung disease or without lung disease (17% vs. 10% vs. 9%, P = 0.017). In-hospital mortality was also higher in patients with an acute pulmonary trigger than in the other two groups, although not significantly (5.7% vs. 1.5% vs. 4.2%, P = 0.13). Survival analysis demonstrated that patients with an acute pulmonary trigger had the worst long-term outcome (P = 0.002). The presence of an acute pulmonary trigger was independently associated with worse long-term mortality (hazard ratio 2.12, 95% confidence interval 1.33-3.38; P = 0.002).

CONCLUSIONS

The present study demonstrates that TTS is related to acute pulmonary triggers in 7% of all TTS patients, which accounts for 21% of patients with physical triggers. The presence of acute pulmonary trigger is associated with a severe in-hospital course and a worse long-term outcome.

Impairment of platelet NO signalling in coronary artery spasm: role of hydrogen sulphide

BACKGROUND AND PURPOSE

The pathophysiology of coronary artery spasm (CAS), with its associated ischaemic crises, is currently poorly understood and treatment is frequently ineffective. In view of increasing evidence that platelet-based defects may occur in CAS patients, we investigated platelet reactivity in CAS patients and whether symptomatic crises reflect activation of platelet-endothelial interactions.

EXPERIMENTAL APPROACH

CAS patients were evaluated during acute and/or chronic symptomatic phases and compared with healthy control subjects. Inhibition of ADP-induced platelet aggregation by the NO donor sodium nitroprusside (SNP) and plasma concentrations of syndecan 1 (glycocalyx shedding marker), tryptase (mast cell activation marker) and platelet microparticles were measured.

KEY RESULTS

Inhibition of platelet aggregation by SNP was diminished in chronic CAS, with further (non-significant) deterioration during symptomatic crises, whereas plasma concentrations of syndecan 1, tryptase and platelet microparticles increased. Treatment of patients with high-dose N-acetylcysteine (NAC) plus glyceryl trinitrate rapidly increased platelet responsiveness to SNP and decreased plasma syndecan 1 concentrations. The effect of NAC on platelet responsiveness to SNP was confirmed in vitro and mimicked by the H₂ S donor NaHS. Conversely, inhibition of enzymatic production of H₂ S attenuated NAC effect.

CONCLUSION AND IMPLICATIONS

CAS is associated with substantial impairment of platelet NO signalling. During acute symptomatic exacerbations, platelet resistance to NO is aggravated, together with mast cell activation and damage to both vasculature and platelets. NAC, via release of H₂ S, reverses platelet resistance to NO and terminates glycocalyx shedding during symptomatic crises: This suggests that H₂ S donors may correct the pathophysiological anomalies underlying CAS.

Age-Related Variations in Takotsubo Syndrome

BACKGROUND

Takotsubo syndrome (TTS) occurs predominantly in post-menopausal women but is also found in younger patients.

OBJECTIVES

This study aimed to investigate age-related differences in TTS.

METHODS

Patients diagnosed with TTS and enrolled in the International Takotsubo Registry between January 2011 and February 2017 were included in this analysis and were stratified by age (younger: ≤50 years, middle-age: 51 to 74 years, elderly: ≥75 years). Baseline characteristics, hospital course, as well as short- and long-term mortality were compared among groups.

RESULTS

Of 2,098 TTS patients, 242 (11.5%) patients were ≤50 years of age, 1,194 (56.9%) were 51 to 74 years of age, and 662 (31.6%) were ≥75 years of age. Younger patients were more often men (12.4% vs. 10.9% vs. 6.3%; p = 0.002) and had an increased prevalence of acute neurological (16.3% vs. 8.4% vs. 8.8%; p = 0.001) or psychiatric disorders (14.1% vs. 10.3% vs. 5.6%; p < 0.001) compared with middle-aged and elderly TTS patients. Furthermore, younger patients had more often cardiogenic shock (15.3% vs. 9.1% vs. 8.1%; p = 0.004) and had a numerically higher in-hospital mortality (6.6% vs. 3.6% vs. 5.1%; p = 0.07). At multivariable analysis, younger (odds ratio: 1.60; 95% confidence interval: 0.86 to 3.01; p = 0.14) and older age (odds ratio: 1.09; 95% confidence interval: 0.66 to 1.80; p = 0.75) were not independently associated with in-hospital mortality using the middle-aged group as a reference. There were no differences in 60-day mortality rates among groups.

CONCLUSIONS

A substantial proportion of TTS patients are younger than 50 years of age. TTS is associated with severe complications requiring intensive care, particularly in younger patients.

Prognostic value of texture analysis from cardiac magnetic resonance imaging in patients with Takotsubo syndrome: a machine learning based proof-of-principle approach

Cardiac magnetic resonance (CMR) imaging has become an important technique for non-invasive diagnosis of takotsubo syndrome (TTS). The long-term prognostic value of CMR imaging in TTS has not been fully elucidated yet. This study sought to evaluate the prognostic value of texture analysis (TA) based on CMR images in patients with TTS using machine learning. In this multicenter study (InterTAK Registry), we investigated CMR imaging data of 58 patients (56 women, mean age 68 ± 12 years) with TTS. CMR imaging was performed in the acute to subacute phase (median time after symptom onset 4 days) of TTS. TA of the left ventricle was performed using free-hand regions-of-interest in short axis late gadolinium-enhanced and on T2-weighted (T2w) images. A total of 608 TA features adding the parameters age, gender, and body mass index were included. Dimension reduction was performed removing TA features with poor intra-class correlation coefficients (ICC ≤ 0.6) and those being redundant (correlation matrix with Pearson correlation coefficient r > 0.8). Five common machine-learning classifiers (artificial neural network Multilayer Perceptron, decision tree J48, NaïveBayes, RandomForest, and Sequential Minimal Optimization) with tenfold cross-validation were applied to assess 5-year outcome including major adverse cardiac and cerebrovascular events (MACCE). Dimension reduction yielded 10 TA features carrying prognostic information, which were all based on T2w images. The NaïveBayes machine learning classifier showed overall best performance with a sensitivity of 82.9% (confidence interval (CI) 80-86.2), specificity of 83.7% (CI 75.7-92), and an area-under-the receiver operating characteristics curve of 0.88 (CI 0.83-0.92). This proof-of-principle study is the first to identify unique T2w-derived TA features that predict long-term outcome in patients with TTS. These features might serve as imaging prognostic biomarkers in TTS patients.

Common Comorbidities that Alter Heart Failure Prognosis - shaping new thinking for practice

At least half of all heart failure (CHF) patients will have a comorbidity that could be undertreated, requires additional speciality input and/or polypharmacy. These patients are then at risk from iatrogenic and disease related complications and readmissions if not closely supervised. Common comorbidities of relevance are cardiorenal and cardiometabolic syndromes (DM, obesity, OSA), chronic airways disease, elderly age and accompanying therapeutic optimisation. The structure of community practice often leaves primary, speciality and allied health care in silos. For example, cardiology speciality training in Australia creates excellent sub-specialists to deliver on the diagnostics and therapeutic advances. A casualty of this process has been gradual alienation of general cardiology towards general internal medical specialists and GP's. The consequences are largely noticed in community practice. The issue are compounded by suboptimal communication of information. This review explores these issues from a cardiology sub-speciality lens, firstly cross speciality areas important for cardiologist to maintain their skill and finally a brief overview of disease management and identifying game changing common denominators such as endothelial dysfunction and self-management.

Takotsubo Syndrome: Finally Emerging From the Shadows?

It is now 30 years since Japanese investigators first described Takotsubo Syndrome (TTS) as a disorder occurring mainly in ageing women, ascribing it to the impact of multivessel coronary artery spasm. During the intervening period, it has become clear that TTS involves relatively transient vascular injury, followed by prolonged myocardial inflammatory and eventually fibrotic changes. Hence symptomatic recovery is generally slow, currently an under-recognised issue. It appears that TTS is induced by aberrant post-β₂-adrenoceptor signalling in the setting of "surge" release of catecholamines. Resultant activation of nitric oxide synthases and increased inflammatory vascular permeation lead to prolonged myocardial infiltration with macrophages and associated oedema formation. Initially, the diagnosis of TTS was made via exclusion of relevant coronary artery stenoses, plus the presence of regional left ventricular hypokinesis. However, detection of extensive myocardial oedema on cardiac MRI imaging offers a specific basis for diagnosis. No adequate methods are yet available for definitive diagnosis of TTS at hospital presentation. Other major challenges remaining in this area include understanding of the recently demonstrated association between TTS and antecedent cancer, the development of effective treatments to reduce risk of short-term (generally due to shock) and long-term mortality, and also to accelerate symptomatic recovery.

Does high on-treatment platelet aggregability reflect poor individual response to clopidogrel?

INTRODUCTION

On-treatment platelet aggregability represents the major form of functional assessment for patients treated with P2Y₁₂ receptor antagonists, with "high" on-treatment platelet aggregability (HTPA) predicting thrombotic risk. However HTPA reflects a variable combination of pre-treatment hyperaggregability and poor response to P2Y₁₂ antagonists. We have previously shown that integrity of platelet adenylate cyclase/cAMP signaling, assessed with PGE₁, is a strong predictor of individual responses to clopidogrel. We therefore sought to determine the extent to which HTPA reflects impaired platelet responsiveness to clopidogrel.

METHODS

Using data from our previous investigations of acute and sub-acute effects of clopidogrel, we analyzed the relationship between on-treatment aggregability and acute/steady state responsiveness to clopidogrel, utilizing ADP, the thromboxane A₂ mimetic U46619, and thrombin receptor-activating peptide (TRAP) as pro-aggregants. The relationship between anti-aggregatory response to PGE₁ and both on-treatment and pre-treatment aggregability was also examined.

RESULTS AND CONCLUSIONS

With all 3 pro-aggregants, (1) response to clopidogrel after 4 h, as measured by ΔADP response, exhibits a strong inverse relationship with on-treatment aggregation, with a similarly inverse relationship between pre-treatment PGE₁ response and on-treatment aggregability; (2) there is a weaker inverse relationship between clopidogrel response and pre-treatment platelet aggregability, and a significant inverse relationship between pre-treatment PGE₁ response and pre-treatment platelet aggregability. Furthermore, pre-treatment PGE₁ response also predicts on-treatment platelet aggregability in response to ADP at steady state. Thus, HTPA largely represents clopidogrel resistance.

Cardiac arrest in takotsubo syndrome: results from the InterTAK Registry

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 < 0.001) and 5-year mortality (68.9% vs. 16.7%, P < 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.

Prolonged suppression of the anti-oxidant/anti-inflammatory effects of BNP post-Takotsubo syndrome

AIMS

Takotsubo syndrome (TTS) episodes are primarily initiated by 'pulse' release of catecholamines inducing neutrophil infiltration and myocardial inflammation in susceptible individuals (largely ageing women). Evidence of myocardial inflammation and associated energetic impairment persists for ≥ 3 months post-acute TTS episodes, suggesting the existence of additional 'perpetuating' mechanisms. The effects of B-type natriuretic peptide (BNP) in suppressing superoxide (O₂ ^- ) release from neutrophils are transiently impaired in acute heart failure. We also evaluated the extent and duration of BNP-induced suppression of O₂ ^- release post-TTS.

METHODS AND RESULTS

TTS patients were studied acutely (n = 34) and 3 months thereafter (n = 13) and compared with control subjects (n = 25). O₂ ^- generation from neutrophils, triggered by N-formyl-methionyl-leucyl-phenylalanine and phorbol myristate acetate, and its suppression by BNP, were measured in vitro. Determinants of variability in BNP effect were sought via univariate and multivariate analyses. Relative to control subjects, in TTS patients, BNP suppression of both phorbol myristate acetate and N-formyl-methionyl-leucyl-phenylalanine-induced O₂ ^- release was impaired acutely (P < 0.05 for both); this did not improve over the 3-month recovery period, despite treatment with conventional anti-failure medication in 85% of patients. No significant correlates of BNP effect (other than TTS) were identified.

CONCLUSIONS

(1) While TTS is associated with marked and prolonged release of BNP, there is virtually total loss of the ability of BNP to suppress neutrophil O₂ ^- release and its impact on tissue inflammation. (2) BNP responses do not recover for at least 3 months post-attacks, suggesting that this might contribute to perpetuation of myocardial inflammation in TTS patients.

Nitroxyl: A Novel Strategy to Circumvent Diabetes Associated Impairments in Nitric Oxide Signaling

Diabetes is associated with an increased mortality risk due to cardiovascular complications. Hyperglycemia-induced oxidative stress underlies these complications, leading to an impairment in endogenous nitric oxide (NO•) generation, together with reductions in NO• bioavailability and NO• responsiveness in the vasculature, platelets and myocardium. The latter impairment of responsiveness to NO•, termed NO• resistance, compromises the ability of traditional NO•-based therapeutics to improve hemodynamic status during diabetes-associated cardiovascular emergencies, such as acute myocardial infarction. Whilst a number of agents can ameliorate (e.g. angiotensin converting enzyme [ACE] inhibitors, perhexiline, statins and insulin) or circumvent (e.g. nitrite and sGC activators) NO• resistance, nitroxyl (HNO) donors offer a novel opportunity to circumvent NO• resistance in diabetes. With a suite of vasoprotective properties and an ability to enhance cardiac inotropic and lusitropic responses, coupled with preserved efficacy in the setting of oxidative stress, HNO donors have intact therapeutic potential in the face of diminished NO• signaling. This review explores the major mechanisms by which hyperglycemia-induced oxidative stress drives NO• resistance, and the therapeutic potential of HNO donors to circumvent this to treat cardiovascular complications in type 2 diabetes mellitus.

Antecedent cancer in Takotsubo syndrome predicts both cardiovascular and long-term mortality

Background

Takotsubo syndrome (TTS), primarily an acute myocardial inflammatory condition engendered by catecholamine exposure, is associated with similar long-term mortality rates to those of patients with acute myocardial infarction. However, there is increasing evidence of a nexus between TTS and underlying malignancies:- many patients have antecedent cancer (A/Ca), while incremental risk of late cancer-related death has also been reported.

Purpose

To evaluate potential interactions between A/Ca among TTS patients and both early and late clinical course.

Methods

Three hundred forty-six consecutive TTS patients [aged 69 ± 13 (SD) years, males: 8.2%] were prospectively followed up for a median duration of 4.1 (IQR 2.2–6.4) years. Associations between A/Ca and severity of acute attacks, in-hospital complications and long-term death rates were sought utilising univariate analyses followed by multiple logistic regression analysis.

Results

A/Ca (present in 16.8% of patients) was associated with (i) greater elevation of hs-CRP and NT-proBNP concentrations (p = 0.01 and 0.04, respectively), (ii) more complicated in-hospital clinical course, with major adverse cardiac events (MACE) in 30.9% of patients, compared to 18.2% in non-A/Ca patients (p = 0.04). Long-term all-cause mortality rate was also greater [hazard ratio (HR) = 2.4, p = 0.0001] in A/Ca patients, with an excess cardiovascular (CVS) fatality rate (HR = 3.1, p = 0.001). On multivariate analysis, male gender, peak plasma concentrations of normetanephrine and hs-CRP, early arrhythmias and development of shock, but not A/Ca per se, were all independently associated with increased long-term mortality rate. Furthermore, patients discharged on β-adrenoceptor antagonists (βBl) or angiotensin converting enzyme inhibitors/ angiotensin receptor blockers (ACEi/ARB) had lower long-term mortality rates (β = − 0.2, p = 0.01; β = − 0.14, p = 0.05, respectively).

Conclusions

(1) A/Ca is associated with greater clinical severity of initial TTS attacks and substantially greater long-term CVS-related as well as all-cause mortality.

(2) Post-discharge therapy with either βBl or ACEi/ARB is associated with reductions in long-term mortality rates.

Overall, the current data suggest operation of substantial interactions between neoplasia and TTS, both at the level of pathogenesis and of outcomes.

Nitric Oxide Resistance, Induced in the Myocardium by Diabetes, Is Circumvented by the Nitric Oxide Redox Sibling, Nitroxyl

Aim: Impairment of tissue responsiveness to exogenous and endogenous nitric oxide (NO^•), known as NO^• resistance, occurs in many cardiovascular disease states, prominently in diabetes and especially in the presence of marked hyperglycemia. In this study, we sought to determine in moderate and severe diabetes (i) whether NO^• resistance also occurs in the myocardium, and (ii) whether the NO^• redox sibling nitroxyl (HNO) circumvents this. Results: The spectrum of acute NO^• effects (induced by diethylamine-NONOate), including vasodilation, and enhanced myocardial contraction and relaxation were impaired by moderately diabetic rats ([blood glucose] ∼20 mM). In contrast, acute HNO effects (induced by isopropylamine-NONOate) were preserved even in more severe diabetes ([blood glucose] >28 mM). Intriguingly, the positive inotropic effects of HNO were significantly enhanced in diabetic rat hearts. Further, progressive attenuation of soluble guanylyl cyclase (sGC) contribution to myocardial NO^• responses occurred with increasing severity of diabetes. Nevertheless, activation of sGC by HNO remained intact in the myocardium. Innovation: Diabetes is associated with marked attenuation of vascular and myocardial effects of NO and NO donors, and this NO^• resistance is circumvented by HNO, suggesting potential therapeutic utility for HNO donors in cardiovascular emergencies in diabetics. Conclusion: These results provide the first evidence that NO^• resistance occurs in diabetic hearts, and that HNO largely circumvents this problem. Further, the positive inotropic and lusitropic effects of HNO are enhanced in a severely diabetic myocardium, a finding that warrants further mechanistic interrogation. The results support a potential role for therapeutic HNO administration in acute treatment of ischemia and/or heart failure in diabetics.

Inorganic nitrate and nitrite supplementation fails to improve skeletal muscle mitochondrial efficiency in mice and humans

BACKGROUND

Inorganic nitrate, abundant in leafy green vegetables and beetroot, is thought to have protective health benefits. Adherence to a Mediterranean diet reduces the incidence and severity of coronary artery disease, whereas supplementation with nitrate can improve submaximal exercise performance. Once ingested, oral commensal bacteria may reduce nitrate to nitrite, which may subsequently be reduced to nitric oxide during conditions of hypoxia and in the presence of "nitrite reductases" such as heme- and molybdenum-containing enzymes.

OBJECTIVE

We aimed to explore the putative effects of inorganic nitrate and nitrite on mitochondrial function in skeletal muscle.

METHODS

Mice were subjected to a nitrate/nitrite-depleted diet for 2 wk, then supplemented with sodium nitrate, sodium nitrite, or sodium chloride (1 g/L) in drinking water ad libitum for 7 d before killing. Skeletal muscle mitochondrial function and expression of uncoupling protein (UCP) 3, ADP/ATP carrier protein (AAC) 1 and AAC2, and pyruvate dehydrogenase (PDH) were assessed by respirometry and Western blotting. Studies were also undertaken in human skeletal muscle biopsies from a cohort of coronary artery bypass graft patients treated with either sodium nitrite (30-min infusion of 10 μmol/min) or vehicle [0.9% (wt:vol) saline] 24 h before surgery.

RESULTS

Neither sodium nitrate nor sodium nitrite supplementation altered mitochondrial coupling efficiency in murine skeletal muscle, and expression of UCP3, AAC1, or AAC2, and PDH phosphorylation status did not differ between the nitrite and saline groups. Similar results were observed in human samples.

CONCLUSIONS

Sodium nitrite failed to improve mitochondrial metabolic efficiency, rendering this mechanism implausible for the purported exercise benefits of dietary nitrate supplementation. This trial was registered at clinicaltrials.gov as NCT04001283.

Intraventricular Thrombus Formation and Embolism in Takotsubo Syndrome

Objective:

Takotsubo syndrome (TTS) is characterized by acute left ventricular dysfunction, which can contribute to intraventricular thrombus and embolism. Still, prevalence and clinical impact of thrombus formation and embolic events on outcome of TTS patients remain unclear. This study aimed to investigate clinical features and outcomes of patients with and without intraventricular thrombus or embolism. Additionally, factors associated with thrombus formation or embolism, as well as predictors for mortality, were identified.

Approach and Results:

TTS patients enrolled in the International Takotsubo Registry at 28 centers in Australia, Europe, and the United States were dichotomized according to the occurrence/absence of intraventricular thrombus or embolism. Patients with intraventricular thrombus or embolism were defined as the ThrombEmb group. Of 1676 TTS patients, 56 (3.3%) patients developed intraventricular thrombus and/or embolism following TTS diagnosis (median time interval, 2.0 days [range, 0–38 days]). Patients in the ThrombEmb group had a different clinical profile including lower left ventricular ejection fraction, higher prevalence of the apical type, elevated levels of troponin and inflammatory markers, and higher prevalence of vascular disease. In a Firth bias-reduced penalized-likelihood logistic regression model apical type, left ventricular ejection fraction ≤30%, previous vascular disease, and a white blood cell count on admission >10×10 3 cells/μL emerged as independent predictors for thrombus formation or embolism.

Conclusions:

Intraventricular thrombus or embolism occur in 3.3% of patients in the acute phase of TTS. A simple risk score including clinical parameters associated with intraventricular thrombus formation or embolism identifies patients at increased risk.

Clinical Trial Registration:

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01947621.

International Expert Consensus Document on Takotsubo Syndrome (Part II): Diagnostic Workup, Outcome, and Management

The clinical expert consensus statement on takotsubo syndrome (TTS) part II focuses on the diagnostic workup, outcome, and management. The recommendations are based on interpretation of the limited clinical trial data currently available and experience of international TTS experts. It summarizes the diagnostic approach, which may facilitate correct and timely diagnosis. Furthermore, the document covers areas where controversies still exist in risk stratification and management of TTS. Based on available data the document provides recommendations on optimal care of such patients for practising physicians.

International Expert Consensus Document on Takotsubo Syndrome (Part I): Clinical Characteristics, Diagnostic Criteria, and Pathophysiology

Takotsubo syndrome (TTS) is a poorly recognized heart disease that was initially regarded as a benign condition. Recently, it has been shown that TTS may be associated with severe clinical complications including death and that its prevalence is probably underestimated. Since current guidelines on TTS are lacking, it appears timely and important to provide an expert consensus statement on TTS. The clinical expert consensus document part I summarizes the current state of knowledge on clinical presentation and characteristics of TTS and agrees on controversies surrounding TTS such as nomenclature, different TTS types, role of coronary artery disease, and etiology. This consensus also proposes new diagnostic criteria based on current knowledge to improve diagnostic accuracy.

Clinical Predictors and Prognostic Impact of Recovery of Wall Motion Abnormalities in Takotsubo Syndrome: Results From the International Takotsubo Registry

Background

Left ventricular (LV) recovery in takotsubo syndrome (TTS) occurs over a wide‐ranging interval, varying from hours to weeks. We sought to investigate the clinical predictors and prognostic impact of recovery time for TTS patients.

Methods and Results

TTS patients from the International Takotsubo Registry were included in this study. Cut‐off for early LV recovery was determined to be 10 days after the acute event. Multivariable logistic regression was used to assess factors associated with the absence of early recovery. In‐hospital outcomes and 1‐year mortality were compared for patients with versus without early recovery. We analyzed 406 patients with comprehensive and serial imaging data regarding time to recovery. Of these, 191 (47.0%) had early LV recovery and 215 (53.0%) demonstrated late LV improvement. Patients without early recovery were more often male (12.6% versus 5.2%; P=0.011) and presented more frequently with typical TTS (76.3% versus 67.0%, P=0.040). Cardiac and inflammatory markers were higher in patients without early recovery than in those with early recovery. Patients without early recovery showed unfavorable 1‐year outcome compared with patients with early recovery (P=0.003). On multiple logistic regression, male sex, LV ejection fraction <45%, and acute neurologic disorders were associated with the absence of early recovery.

Conclusions

TTS patients without early LV recovery have different clinical characteristics and less favorable 1‐year outcome compared with patients with early recovery. The factors associated with the absence of early recovery included male sex, reduced LV ejection fraction, and acute neurologic events.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01947621.

P813Iatrogenic takotsubo syndrome: incidence and impact

Background

Although Takotsubo syndrome (TTS) was once considered to be rare and largely benign, it is now recognised to represent a major cause of cardiac morbidity and mortality, especially in aging women. The biochemical precipitant of attacks of TTS is an increase in catecholamine concentrations within the myocardium, engendering inflammatory activation via biased post-receptor signalling at myocardial β2-adrenoceptor level. Cases of TTS have been reported in patients treated with catecholamines, and with antidepressants which limit catecholamine re-uptake. In the current investigation, we sought to delineate the extent and potential impact of this “iatrogenic” form of TTS.

Methods/Results

Patients' data from a regional registry of 272 consecutive cases of TTS were evaluated. After exclusion of patients (n=14) in whom TTS has occurred in association with life threatening extracardiac disease states, a total of 47 (18%) of patients were identified as having antecedent exposure to potentially “iatrogenic” agents (antidepressants in 29 cases, β2-adrenoceptor agonists in 14). Demographics, including proportion of male patients, did not differ significantly between patients with and without “iatrogenic” TTS, but plasma concentrations of the catecholamine metabolite normetanephrine tended to be greater (median 1160 vs. 950 pmol/L; p=0.07). Long-term survival (median follow-up 3.5 years) was marginally (p=0.09) worse for patients with “iatrogenic” TTS.

Conclusion

(1) A potentially iatrogenic component of precipitation (via iatrogenic elevation of catecholamine levels and β2-adrenoceptor stimulation) is present in a substantial proportion of patients.

(2) In such patients there is an implication of increased long-term mortality risk, potentially accentuated by continued administration of the precipitating agent(s).