'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 (PM2.5) 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) PM2.5 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 (rs = 0.26, P = .005) with increased incidence of acute coronary syndromes, while there were similar, but nonsignificant correlations for PM2.5 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 PM2.5 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.

Risk factors for a broken heart: understanding drug-induced causes for Takotsubo syndrome and pharmacological treatment options.

INTRODUCTION: Takotsubo syndrome (TTS) is an acute inflammatory disorder involving first the vasculature and then the myocardium. It occurs relatively frequently, especially in aging women after acute physical and emotional stress. There is also increasing recognition that TTS attacks are sometimes precipitated by pharmacotherapy. AREAS COVERED: The pathogenesis of TTS is described, including components of a complex biochemical 'cascade' centering on aberrant post-receptor signaling following ß2-adrenoceptors stimulation and resultant nitric oxide (NO) release and development of nitrosative stress. Examples and significance of drug-induced TTS are also described. Currently available therapeutic information regarding TTS is presented, both for management of patients acutely and in the long-term. Furthermore, development of specific therapies to block components of the pathogenetic TTS 'cascade' is discussed. EXPERT OPINION: The biochemical 'cascade' in TTS revolves around an aberrant post-receptor response to ß2-adrenoceptor stimulation, increased responsiveness to NO and triggering of activation of poly(ADP-ribose) polymerase (PARP). In theory, interruption of this 'cascade' represents a logical approach to improving both symptomatic status and survival post TTS. Currently, there is some evidence supporting routine long-term treatment post TTS with either ACE inhibitors or angiotensin receptor antagonists, both to reduce risk of recurrence and to improve survival. Results of ongoing controlled clinical trials are awaited.

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.

Incidence and clinical/laboratory correlates of early hypotension in takotsubo syndrome.

AIMS: Takotsubo syndrome (TTS) is a form of acute myocardial inflammation, often triggered by catecholamine release surges, which accounts for approximately 10% of 'myocardial infarctions' in female patients above the age of 50. Its associated substantial risk of in-hospital mortality is mainly driven by the development of hypotension and shock. While hypotension is induced largely by factors other than low cardiac output, its precise cause is unknown, and clinical parameters associated with hypotension have not been identified previously. We therefore sought to identify the incidence and clinical/laboratory correlates of early hypotension in TTS. METHODS AND RESULTS: We analysed the in-hospital data of patients recruited to the South Australian TTS Registry. Associations between the development of hypotension, patient demographics, severity of the acute TTS attack, and key biochemical markers were sought. One hundred thirteen out of 319 patients (35%) were hypotensive (median systolic blood pressure 80 mmHg) during their index hospitalization. Development of hypotension preceded all in-hospital deaths (n = 8). On univariate analyses, patients who developed hypotension had lower left ventricular ejection fraction (P = 0.009), and higher plasma N-terminal pro brain natriuretic peptide and troponin-T concentrations (P = 0.046 and 0.008, respectively), all markers of severity of the TTS attack; hypotension also occurred less commonly in male than in female patients (P = 0.014). On multivariate linear regression analysis, female sex and lower left ventricular ejection fraction were independent correlates of the development of hypotension (P = 0.009 and 0.010, respectively). CONCLUSIONS: Early development of hypotension is very common in TTS, and its presence is associated with a substantial risk of in-hospital mortality. Hypotension is a marker of severe TTS attacks and occurs more commonly in female TTS patients.

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-ß2-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.

Incremental "Therapeutic" Myocardial Exposure to Catecholamines: Incidence and Impact in Takotsubo Syndrome.

BACKGROUND: Although Takotsubo syndrome (TS) was once considered to be rare and largely benign, it is now recognized to represent a major cause of cardiac morbidity and mortality, especially in ageing women. The biochemical precipitant of attacks of TS is an increase in catecholamine concentrations within the myocardium, engendering inflammatory activation via biased post-receptor signalling at myocardial ß2-adrenoceptor level. Cases of TS 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 TS. METHODS/RESULTS: Patients' data from a regional registry of 301 consecutive cases of TS were evaluated after exclusion of patients (n = 20) in whom TS had occurred in association with life threatening extracardiac disease states. A total of 55 (18%) of patients were identified as having antecedent exposure to potentially "iatrogenic" agents (tricyclic antidepressants in 24 cases, ß2-adrenoceptor agonists in 15). Demographics, including proportion of male patients, did not differ significantly between patients with and without "iatrogenic" TS, but plasma concentrations of the catecholamine metabolite normetanephrine tended to be greater (median 1149 pmol/L vs 938 pmol/L; p = 0.03). Long-term survival (median follow-up 3 years) was marginally (p = 0.13) worse for patients with "iatrogenic" TS. CONCLUSION: Potentially iatrogenic precipitation of TS attacks (via iatrogenic elevation of catecholamine levels and ß2-adrenoceptor stimulation) is common, associated with greater elevation of plasma normetanephrine concentrations, and also with a trend towards increased long-term mortality when compared to the remainder of TS patients.

The N-AcetylCysteine and RAMipril in Takotsubo Syndrome Trial (NACRAM): Rationale and design of a randomised controlled trial of sequential N-Acetylcysteine and ramipril for the management of Takotsubo Syndrome.

BACKGROUND: Takotsubo Syndrome(TTS), contrary to historical reports, is now increasingly recognised to be associated with substantial mortality and morbidity, both in the short- and long-term. Although TTS is often precipitated by a catecholamine "pulse", in-hospital hypotension is a common occurrence, increasing the risk of mortality. Furthermore, despite the transient catecholamine stimulus, there is increasing evidence that there are significant long term sequelae, including persistently impaired left ventricular(LV) systolic dysfunction, myocardial oedema with fibrosis, as well as persistent impairment of quality of life. A definitive therapeutic option to limit the extent of initial myocardial injury, and to accelerate recovery in TTS is therefore justified. However to date, there has been a lack of prospective studies in this area. DESIGN AND RATIONALE: NACRAM is a multi-centre, randomised, placebo-controlled trial, sequentially testing early use of intravenous N-acetylcysteine(NAC), followed by/or oral ramipril for 12 weeks. The rationale for utilising these agents is related to their effects on limiting nitrosative stress and expression of the inflammasome activator thioredoxin interacting protein(TXNIP); both processes fundamental to the pathogenesis of TTS. END POINTS: NACRAM is assessing resolution of myocardial oedema on cardiac magnetic resonance imaging(CMR), improvements in LV systolic function as measured by global longitudinal strain(GLS) on echocardiography, quality of life, and inflammatory markers. DISCUSSION: To the best of our knowledge, NACRAM will be the first prospective study to help definitively evaluate a therapeutic option in acute attacks of TTS.

Clinician agreement and influence of medication-related characteristics on assessment of polypharmacy.

It is not known how clinicians assess polypharmacy or the medication-related characteristics that influence their assessment. The aim of this study was to examine the level of agreement between clinicians when assessing polypharmacy and to identify medication-related characteristics that influence their assessment. Twenty cases of patients with varying levels of comorbidity and polypharmacy were used to examine clinician assessment of polypharmacy. Medicine-related factors within the cases included Beers and STOPP Criteria medicines, falls-risk medicines, drug burden index (DBI) medicines, medicines causing postural hypotension, and pharmacokinetic drug-drug interactions. Clinicians were asked to rate cases on the degree of polypharmacy, likelihood of harm, and potential for the medication list to be simplified. Inter-rater reliability analysis, correlations, and multivariate logistic regression analyses were conducted to identify medicine factors associated with clinicians' assessment. Eighteen expert clinicians were recruited (69.2% response rate). Strong agreement was observed in clinicians' assessment of polypharmacy (intraclass correlation coefficients [ICC] = 0.94), likelihood to cause harm (ICC = 0.89), and ability to simplify medication list (ICC = 0.90). Multivariate analyses demonstrated number of medicines (P < 0.0001) and DBI scores (P = 0.047) were significantly associated with assessment of polypharmacy. Medicines associated with harm were significantly associated with the number of medicines (P = 0.01) and Beers criteria medicines (P = 0.003). Ability to simplify the medication regimen was significantly associated with number of medicines (P = 0.03) and medicines from the STOPP criteria (P = 0.018). Among clinicians, strong consensus exists with regard to assessment of polypharmacy, medication harm, and ability to simplify medications. Definitions of polypharmacy need to take into account not only the numbers of medicines but also potential for medicines to cause harm or be inappropriate, and validate them against clinical outcomes.