Serum cardiac troponin T levels as an indicator of myocardial injury in ischemic and hemorrhagic stroke patients

The insular cortex, autonomic asymmetry and cardiovascular control: looking at the right side of stroke

PURPOSE

Evidence from animal and human studies demonstrates that cortical regions play a key role in autonomic modulation with a differential role for some brain regions located in the left and right brain hemispheres. Known as autonomic asymmetry, this phenomenon has been demonstrated by clinical observations, by experimental models, and currently by combined neuroimaging and direct recordings of sympathetic nerve activity. Previous studies report peculiar autonomic-mediated cardiovascular alterations following unilateral damage to the left or right insula, a multifunctional key cortical region involved in emotional processing linked to autonomic cardiovascular control and featuring asymmetric characteristics.

METHODS

Based on clinical studies reporting specific damage to the insular cortex, this review aims to provide an overview of the prognostic significance of unilateral (left or right hemisphere) post-insular stroke cardiac alterations. In addition, we review experimental data aiming to unravel the central mechanisms involved in post-insular stroke cardiovascular complications.

RESULTS AND CONCLUSION

Current clinical and experimental data suggest that stroke of the right insula  can present a worse cardiovascular prognosis.

Brain-Heart Axis and the Inflammatory Response: Connecting Stroke and Cardiac Dysfunction

BACKGROUND

In recent years, the mechanistic interaction between the brain and heart has been explored in detail, which explains the effects of brain injuries on the heart and those of cardiac dysfunction on the brain. Brain injuries are the predominant cause of post-stroke deaths, and cardiac dysfunction is the second leading cause of mortality after stroke onset.

SUMMARY

Several studies have reported the association between brain injuries and cardiac dysfunction. Therefore, it is necessary to study the influence on the heart post-stroke to understand the underlying mechanisms of stroke and cardiac dysfunction. This review focuses on the mechanisms and the effects of cardiac dysfunction after the onset of stroke (ischemic or hemorrhagic stroke).

KEY MESSAGES

The role of the site of stroke and the underlying mechanisms of the brain-heart axis after stroke onset, including the hypothalamic-pituitary-adrenal axis, inflammatory and immune responses, brain-multi-organ axis, are discussed.

Elevated troponin levels as a predictor of mortality in patients with acute stroke: a systematic review and meta-analysis

Background and Aim

The prognostic potential of cardiac troponin (cTn) in acute stroke patients has been a subject of ongoing debate. Our objective was to provide a comprehensive evidence for predicting mortality in acute stroke patients by using the elevated troponin levels.

Methods

We conducted an extensive literature search, including PubMed, EMbase, and Trip Databases, covering studies published up to September 30, 2023. We computed risk ratios (RR) with 95% confidence intervals (CIs), performed sensitivity analysis, and conducted trial sequential analysis (TSA).

Results

In total, 53 studies were analyzed, with 37 focusing on acute ischemic stroke (AIS), 11 on subarachnoid hemorrhage (SAH), and 7 on Intracerebral hemorrhage (ICH). Elevated cTn levels were significantly showed a higher predictive risk for In-hospital mortality in both AIS (RR=3.80, 95% CI; 2.82 to 5.12) as well as SAH (RR=2.23, 95% CI; 1.64 to 3.02). However, no significant predictive risk between elevated cTn levels and in-hospital mortality for ICH patients (RR=1.13, 95% CI: 0.46 to 2.79). A similar pattern was observed for elevated cTn levels, indicating an increased risk of last follow-up mortality for AIS (RR=2.41, 95% CI: 1.98 to 2.93) and SAH (RR=3.08, 95% CI: 2.25 to 4.21).

Conclusion

Elevated troponin levels can serve as a promising predictive marker for both in-hospital and last follow-up mortality in AIS and SAH patients but not in ICH patients. Further prospective studies are needed to validate our findings along with exploring the preventive management of mortality in acute stroke settings.

Aerobic Training and Mobilization Early Post-stroke: Cautions and Considerations

Knowledge gaps exist in how we implement aerobic exercise programs during the early phases post-stroke. Therefore, the objective of this review was to provide evidence-based guidelines for pre-participation screening, mobilization, and aerobic exercise training in the hyper-acute and acute phases post-stroke. In reviewing the literature to determine safe timelines of when to initiate exercise and mobilization we considered the following factors: arterial blood pressure dysregulation, cardiac complications, blood-brain barrier disruption, hemorrhagic stroke transformation, and ischemic penumbra viability. These stroke-related impairments could intensify with inappropriate mobilization/aerobic exercise, hence we deemed the integrity of cerebral autoregulation to be an essential physiological consideration to protect the brain when progressing exercise intensity. Pre-participation screening criteria are proposed and countermeasures to protect the brain from potentially adverse circulatory effects before, during, and following mobilization/exercise sessions are introduced. For example, prolonged periods of standing and static postures before and after mobilization/aerobic exercise may elicit blood pooling and/or trigger coagulation cascades and/or cerebral hypoperfusion. Countermeasures such as avoiding prolonged standing or incorporating periodic lower limb movement to activate the venous muscle pump could counteract blood pooling after an exercise session, minimize activation of the coagulation cascade, and mitigate potential cerebral hypoperfusion. We discuss patient safety in light of the complex nature of stroke presentations (i.e., type, severity, and etiology), medical history, comorbidities such as diabetes, cardiac manifestations, medications, and complications such as anemia and dehydration. The guidelines are easily incorporated into the care model, are low-risk, and use minimal resources. These and other strategies represent opportunities for improving the safety of the activity regimen offered to those in the early phases post-stroke. The timeline for initiating and progressing exercise/mobilization parameters are contingent on recovery stages both from neurobiological and cardiovascular perspectives, which to this point have not been specifically considered in practice. This review includes tailored exercise and mobilization prescription strategies and precautions that are not resource intensive and prioritize safety in stroke recovery.

Myocardial ischemic changes of electrocardiogram in intracerebral hemorrhage: A case report and review of literature

BACKGROUND

Cardiac injury may occur after acute pathology of central nervous system (CNS) without any evidence of primary cardiac diseases. The resulting structural and/or functional changes are called cerebrocardiac syndrome (CCS). The great majority of studies have been performed in patients with subarachnoid hemorrhage (SAH), while CCS data after intracerebral hemorrhage (ICH) are rare. It may cause diagnostic and therapeutic pitfalls for the clinician due to a lack of specific clinical manifestations and diagnostic methods. Understanding the underlying pathophysiological and molecular mechanism(s) following cerebrovascular incidents will help to implement prevention and treatment strategies to improve the prognosis.

CASE SUMMARY

A 37-year-old man with a history of hypertension presented to our department on an emergency basis because of a sudden dizziness and left limb weakness. Cerebral computed tomography (CT) suggested ICH in the occipital and parietal lobes, and the chosen emergency treatment was hematoma evacuation. Left ventricular (LV) dysfunction occurred after the next 48 h and the electrocardiogram (ECG) showed non-ST elevation myocardial infarction. CCS was suspected first in the context of ICH due to the negative result of the coronary CT angiogram.

CONCLUSION

Misinterpretation of ischemic-like ECGs may lead to unnecessary or hazardous interventions and cause undue delay of rehabilitation after stroke. Our objective is to highlight the clinical implications of CCS and we hope the differential diagnoses will be considered in patients with acute CNS diseases.

Is Troponin really a reliable marker in patients with acute ischemic stroke?

BACKGROUND AND PURPOSE

Cardiac troponin I (cTnI) is a reliable marker to diagnose acute myocardial infarction, but the pathophysiological explanation for the increase in cTnI levels in patients with acute ischemic stroke (IS) remains unknown. To overcome this question, we aimed to compare serum cTnI levels in acute coronary syndrome (ACS) concomitant with and without stroke. By doing like this, we thought that we could demonstrate the effect of stroke on TrpI level.

METHODS

Serum cTnI levels of 41 patients having ACS with acute IS during hospitalization were compared with 97 control patients having only ACS. Cranial CT was performed to evaluate the lesions. The severity of IS was evaluated objectively by national institutes of health stroke scale.

RESULTS

cTnI levels were found to be similar in both groups. Presence of diabetes mellitus, coronary artery disease and previous myocardial infarction were more frequent in patients with acute IS. The cTnI levels in the patients with the cranial lesion in the anterior circulation was higher (p = 0.039). Presence of acute IS, cTnI level higher than 20 ng/mL and left ventricular ejection fraction < 40% were found to be independent risk factors for mortality (p < 0.05).

CONCLUSIONS

We found that abnormal troponin levels were more likely to be due to cardiac causes than cerebral ones in this first study evaluating the cTnI levels in patients with ACS concomitant with acute IS. The severity of IS, lesion location in the anterior circulation and higher troponin levels were associated with mortality.

Protective effect of troxerutin and cerebroprotein hydrolysate injection on cerebral ischemia through inhibition of oxidative stress and promotion of angiogenesis in rats

Brain ischemia, including cerebral ischemia and cerebrovascular ischemia, leads to poor oxygen supply or cerebral hypoxia, and causes brain tissue death or cerebral infarction/ischemic stroke. The troxerutin and cerebroprotein hydrolysate injection (TCHI), is widely applied in China to improve blood supply in ischemic brain tissues and to enhance neuroprotective effects in clinical practice. However, the benefits and detailed underlying mechanism elaborating the effectiveness of TCHI in cerebrovascular diseases require further investigation. Therefore, in the present study, experimental in vivo and in vitro models were employed to investigate the potential mechanisms of TCHI on cerebral ischemic injury. The results demonstrated that TCHI increased the lactate dehydrogenase levels in the brain homogenate and conversely decreased lactic acid levels. TCHI was further observed to significantly increase superoxide dismutase activity and decrease malondialdehyde levels in ischemic brain tissues. In addition, TCHI significantly induced vascular maturation processes, including proliferation, adhesion, migration and tube formation in cultured human umbilical vein endothelial cells. Additionally, TCHI significantly stimulated microvessel formation in the rat aortic ring and chick chorioallantoic membrane assays. Taken together, these results provided strong evidence that TCHI stimulated angiogenesis at multiple steps, and indicated that TCHI attenuated cerebral ischemic damage through the amelioration of oxidative stress and promotion of angiogenesis.

Decoy receptor-3 regulates inflammation and apoptosis via PI3K/AKT signaling pathway in coronary heart disease

Coronary heart disease is a disease characterized by coronary artery atherosclerosis lesions caused by vascular cavity stenosis, occlusion, myocardial ischemia, hypoxia or necrosis. Previous studies have demonstrated that decoy receptor-3 (DCR-3) can act as a pleiotropic immunomodulation for enhancing angiogenesis, which may be associated with the progression of coronary heart disease. In the present study, ELISA assay was used to investigate the plasma concentration level of DCR-3 in patients with coronary heart disease. The mRNA and protein level of DCR-3 in myocardial cells were determined by reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. The role and molecular mechanism of DCR-3 was also evaluated in myocardial cells in mice with coronary heart disease. The role of small interfering RNA that targeted phosphoinositide 3-kinase (PI3K) in DCR-3 mediated apoptosis was confirmed by terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling and immunofluorescence. C57BL/6 mice with coronary heart disease were used to evaluate the efficacy of DCR-3 on inflammation and apoptosis. The data indicated that plasma concentration level of DCR-3 was downregulated in mice with coronary heart disease and that DCR-3 administration improved symptoms of coronary heart disease and prolonged survival of mice with coronary heart disease. In addition, it was demonstrated that DCR-3 treatment suppressed the inflammatory response and apoptosis of myocardial cells. Circulating DCR-3 concentration levels may be identified as a predictor of coronary heart disease and prognosis of coronary heart disease. Notably, it was also demonstrated that DCR-3 inhibited inflammatory factor expression levels by regulation of the PI3K/protein kinase B (AKT) signaling pathway. Taken together, these results indicate that increasing circulating DCR-3 plasma concentration is associated with degree of coronary heart disease, suggesting that DCR-3 may be a promising drug for the treatment of coronary heart disease via regulating inflammation and apoptosis through the PI3K/AKT signaling pathway.

Short-term remote ischemic conditioning may protect monkeys after ischemic stroke

Objective

We aimed to evaluate the safety and effectiveness of short-term remote ischemic postconditioning (RIPC) in acute stroke monkey models.

Methods

Acute stroke monkeys were allocated to four groups based on the number of limbs exposed to RIPC. RIPC was initiated by 5-min cuff inflation/deflation cycles of the target limb(s) for 5-10 bouts. Vital signs, skin integrity, brain MRI, and serum levels of cardiac enzymes (myoglobin, creatine kinase [CK], CK-muscle/brain [CK-MB]), one inflammatory marker (high-sensitivity C-reactive protein [hsCRP], and one endothelial injury marker (von Willebrand factor [vWF]) were assessed. Spetzler scores were used to assess neurological function.

Results

No significant differences in vital signs or local skin integrity were found. Short-term RIPC did not reduce infarct volume under any condition at the 24th hour after stroke. However, neurological function improved in multi-limb RIPC compared with sham and single-limb RIPC at the 30th day follow-up after stroke. Myoglobin, CK, and CK-MB levels were reduced after multi-limb RIPC, regardless of the number of bouts. Moreover, multi-limb RIPC produced a greater diminution in CK-MB levels, whereas two-limb RIPC was more effective in reducing serum CK levels at the 24th hour after stroke. hsCRP increased after 5 bouts of multi-limb RIPC before decreasing below baseline and single-limb RIPC levels. Serum vWF was decreased at later time points after RIPC in all RIPC groups.

Conclusions

Stroke monkeys in hyperacute stage may benefit from short-term RIPC; however, whether this intervention can be translated into clinical use in patients with acute ischemic stroke warrants further study.

Baseline Troponin T level in stroke and its association with stress cardiomyopathy

BACKGROUND

Differential diagnosis of elevated high sensitive Troponin T (hsTnT) in acute ischemic stroke includes myocardial infarction (MI) and neurogenic stunned myocardium (NSM). The aim of this study was to identify factors associated with baseline hsTnT levels and MI or NSM in acute ischemic stroke.

METHODS

We studied 204 consecutive patients of the prospective acquired Bern Stroke Database with acute ischemic stroke diagnosed by brain MR. All patient histories and cardiac examinations were reviewed retrospectively. Volumetry of lesions on diffusion and perfusion weighted brain imaging (circular singular value decomposition, Tmax >6sec) was performed. Voxel based analysis was performed to identify brain areas associated with hsTnT elevation. Linear regression analysis was used to identify predictors of baseline hsTnT levels and myocardial infarction.

RESULTS

Elevated hsTnT was observed in 58 of the 204 patients (28.4%). The mean age was 68.3 years in the normal hsTnT group and 69.7 years in the elevated hsTnT group. Creatinine (p<0.001, OR 6.735, 95% CI 58.734-107.423), baseline NIHSS score (p = 0.029, OR 2.207, 95% CI 0.675-12.096), ST segment depression (p = 0.025, OR 2.259, 95% CI 2.419-35.838), and negative T waves in baseline ECG (p = 0.002, OR 3.209, 95% CI 13.007-54.564) were associated with hsTnT elevation, while infarct location and size were not. Coronary angiography was performed in 30 of the 204 patients (14.7%) and myocardial infarction was diagnosed in 7 of them (23.3%). Predictive factors for myocardial infarction could not be identified.

CONCLUSION

Elevated baseline baseline hsTnT was associated with NIHSS, creatinine, ST segment depression and inverted T waves, but not with stroke location or size. None of the factors was helpful to differentiate MI and NSM. Therefore, ancillary investigations such as coronary angiography, cardiac MRI or both may be needed to solve the differential diagnosis.

Admission troponin-I predicts subsequent cardiac complications and mortality in acute stroke patients

Purpose

The importance of troponin elevation at stroke presentation remains uncertain. We aimed to assess whether baseline ultrasensitive Troponin I (hs-TnI) predicts cardiac complications and outcome in acute stroke patients.

Method

Stroke patients admitted within 6 h were consecutively enrolled from May 2013 to March 2014. Blood samples were taken at admission to determine hs-TnI by chemiluminescent microparticle immunoassay. hs-TnI > 34.2 pg/ml (male) and >15.6 pg/ml (female) were considered elevated. Complications during in-hospital stay and outcome at 90 days were prospectively recorded. Independent predictors of cardiac complications (heart failure and acute coronary syndrome) and mortality were determined by logistic regression. The additional predictive value of hs-TnI was evaluated by integrated discrimination improvement index. A subanalysis was performed after excluding patients with previous cardiac diseases.

Findings

From 174 patients, 39(22%) had elevated hs-TnI, having these patients higher incidence of cardiac complications (57% versus 19%, p = 0.004). hs-TnI was an independent predictor of cardiac complications (OR = 16.1 (1.7-150.3)) together with diastolic blood pressure (OR = 0.92 (0.86-0.99)). Addition of hs-TnI to clinical variables significantly improved discrimination (IDI = 15.2% (7.8-22.7)). Subanalysis in patients without previous cardiac diseases showed similar results. Elevated hs-TnI was independently associated with 90 days mortality (OR = 3.6 (1.3-9.4)), but addition of hs-TnI to clinical data did not result in an increased discrimination.

Discussion

The present study confers hs-TnI a 2b level of evidence as a diagnostic tool to predict cardiac complications in stroke. Absence of serial hs-TnI measurements and limited sample size are the main weaknesses of the study.

Conclusion

Patients with elevated baseline hs-TnI showed a higher frequency of cardiac complications and a higher mortality. Measurement of hs-TnI in acute stroke might be useful to identify patients at a high risk of cardiac complications and death.

Advanced monitoring of systemic hemodynamics in critically ill patients with acute brain injury

Hemodynamic monitoring is widely used in critical care; however, the impact of such intervention in patients with acute brain injury (ABI) remains unclear. Using PubMed, a systematic review was performed (1966-August 2013), and 118 studies were included. Data were extracted using the PICO approach. The evidence was classified, and recommendations were developed according to the GRADE system. Electrocardiography and invasive monitoring of arterial blood pressure should be the minimal hemodynamic monitoring required in unstable or at-risk patients in the intensive care unit. Advanced hemodynamic monitoring (i.e., assessment of preload, afterload, cardiac output, and global systemic perfusion) could help establish goals that take into account cerebral blood flow and oxygenation, which vary depending on diagnosis and disease stage. Choice of techniques for assessing preload, afterload, cardiac output, and global systemic perfusion should be guided by specific evidence and local expertise. Hemodynamic monitoring is important and has specific indications among ABI patients. Further data are necessary to understand its potential for therapeutic interventions and prognostication.

Elevated Troponin Levels in Acute Stroke Patients Predict Long-term Mortality

BACKGROUND

Elevated plasma levels of troponin in acute stroke patients are common and have in several studies been shown to predict in-hospital and short-term mortality. Little is, however, known about the long-term prognosis of these patients. The aim of this study was to determine patient characteristics and 5-year mortality in patients with acute stroke and troponin elevation on admission.

METHODS

A retrospective cohort study of all consecutive patients with acute stroke and a plasma troponin I (TnI) analyzed on admission to Danderyd Hospital between January 1, 2005, and January 1, 2006 (n = 247). Patient characteristics were obtained from the Swedish National Stroke Register, Riksstroke, as well as hospital records. Mortality data were obtained from the Swedish Cause of Death Register.

RESULTS

There were 133 patients (54%) with TnI less than .03 μg/L (normal), 74 patients (30%) with TnI .03-.11 μg/L (low elevation), and 40 patients (16%) with TnI greater than .11 μg/L (high elevation). TnI elevations were associated with a higher age, prior ischemic stroke, chronic heart failure, renal insufficiency, stroke severity, and ST segment elevation or depression on admission. The rate of hyperlipidemia decreased with increasing TnI. Adjusted for age and comorbidity, elevated TnI values on admission had a significantly and sustained increased mortality over the 5-year follow-up, with a hazard ratio of 1.90 (95% confidence interval, 1.33-2.70).

CONCLUSIONS

Troponin elevation in patients with acute stroke, even when adjusted for several possible confounders, is associated with an almost 2-fold increased risk of 5-year mortality.

Troponin T in acute ischemic stroke

Multiple interactions are considered to occur among the various forms of cardiovascular and cerebrovascular diseases. The aim of this study was to assess the serum level profile of cardiac troponin T (cTnT) in patients with acute ischemic stroke (AIS) to evaluate factors associated with increased serum levels of cTnT. Patients with AIS enrolled in this prospective observational study were admitted to the hospital <12 hours after stroke onset. At admission, and 4 hours later, all patients were subjected to neurologic examinations and brain computed tomography or magnetic resonance imaging; standard laboratory tests, including cTnT and other cardiac markers; and repeated electrocardiography. Correlations between cTnT and several baseline parameters were tested, and multivariate regression analysis was used to assess the predictors of cTnT elevation. In total, 107 consecutive patients with AIS (65 men, mean age 67.2 ± 14.2 years) were enrolled. Thirty-nine patients (36.4%) presented with elevated cTnT above the upper limit of normal. The cTnT levels were correlated significantly with age (r = 0.448) and the levels of N-terminal pro-brain natriuretic peptide (r = 0.528), cystatin C (r = 0.457), creatine kinase-MB mass (r = 0.253), urea (r = 0.281), and albumin (r = -0.219). Multiple logistic regression analysis found creatinine >90 μmol/L (odds ratio 3.45, 95% confidence interval 1.09 to 10.85), N-terminal pro-brain natriuretic peptide (odds ratio 100 μg/L increase 1.09, 95% confidence interval 1.03 to 1.16), and creatine kinase-MB mass (odds ratio per 1 μg/L increase 1.45, 95% confidence interval 1.04 to 2.04) were associated with cTnT elevation in patients with AIS. In conclusion, elevated cTnT can be frequently detected in patients with AIS. To reliably identify patients with current acute myocardial impairment, more in-depth clinical investigation is needed.

Cerebrogenic tachyarrhythmia in acute stroke

The electrocardiac abnormalities following acute stroke are frequent and seen in both ischemic and hemorrhagic stroke. The changes seen in electrocardiogram (ECG) consist of repolarization abnormalities such as ST elevation, ST depression, negative T waves, and QT prolongation. Among tachyarrhythmias, atrial fibrillation is the most common and occurrence of focal atrial tachycardia is very rare though any cardiac arrhythmias can follow acute stroke. We report a case of focal atrial tachycardia following acute ischemic stroke in 50-year-old female without structural heart disease, and their mechanisms and clinical implications.

Cardiovascular and neurological causes of sudden death after ischaemic stroke

Sudden death is an important but widely under-recognised consequence of stroke. Acute stroke can disturb central autonomic control, resulting in myocardial injury, electrocardiographic abnormalities, cardiac arrhythmias, and ultimately sudden death. Experimental and clinical evidence suggests that autonomic imbalance is more frequent after infarcts involving the insular cortex, a crucial region for the control of sympathetic and parasympathetic autonomic functions. Cardiovascular comorbidities increase the risk of cardiac morbidity and mortality after stroke. Thus, many sudden deaths and serious non-fatal cardiac events after stroke are probably due to an interaction between cardiovascular and neurological causes. The exact mechanisms leading to sudden death remain incompletely understood. Further research is needed to investigate the autonomic consequences of acute stroke and to identify patients at high risk of sudden death.

Ischemic-appearing electrocardiographic changes predict myocardial injury in patients with intracerebral hemorrhage

OBJECTIVES

Myocardial injury is common among patients with intracerebral hemorrhage (ICH). However, it is challenging for emergency physicians to recognize acute myocardial injury in this population, as electrocardiographic (ECG) abnormalities are common in this setting. Our objective is to examine whether ischemic-appearing ECG changes predict subsequent myocardial injury in the context of ICH.

METHODS

Consecutive patients with primary ICH presenting to a single academic center were prospectively enrolled. Electrocardiograms were retrospectively reviewed by 3 independent readers. Anatomical areas of ischemia were defined as I and aVL; II, III, and aVF; V(1) to V(4); and V(5) and V(6). Medical record review identified myocardial injury, defined as troponin I or T elevation (cutoff 1.5 and 0.1 ng/mL, respectively), within 30 days.

RESULTS

Between 1998 and 2004, 218 patients presented directly to our emergency department and did not have a do-not-resuscitate/do-not-intubate order; arrival ECGs and troponin levels were available for 206 patients. Ischemic-appearing changes were noted in 41% of patients, and myocardial injury was noted in 12% of patients. Ischemic-appearing changes were more common in patients with subsequent injury (64% vs 37%; P = .02). After multivariable analysis controlling for age and cardiac risk factors, ischemic-appearing ECG changes independently predicted myocardial injury (odds ratio, 3.2; 95% confidence interval, 1.3-8.2). In an exploratory analysis, ischemic-appearing ECG changes in leads I and aVL as well as V(5) and V(6) were more specific for myocardial injury (P = .002 and P = .03, respectively).

CONCLUSION

In conclusion, although a range of ECG abnormalities can occur after ICH, the finding of ischemic-appearing changes in an anatomical distribution can help predict which patients are having true myocardial injury.

Evaluating the role of elevated levels of troponin in acute ischemic stroke

Ischemic heart disease and cerebrovascular diseases may coexist in the same patient, and similar risk factors are shared. However, for several years, experimental and observational data have incessantly indicated that neurologically induced myocardial injury exists. This leaves the clinician with a diagnostic dilemma of how to distinguish between neurologically induced myocardial injury and myocardial infarction prior to the stroke. Since various alterations of the ECG have also been reported in this patient category, it has been suggested that elevated troponin levels are somehow neurologically mediated, thus not resulting from direct cardiac release. This review focuses on the available studies that systematically measured troponin in patients with acute ischemic stroke in order to properly interpret troponin elevations in these patients.

Increases of cardiac troponin in conditions other than acute coronary syndrome and heart failure

BACKGROUND

Although cardiac troponin (cTn) is a cornerstone marker in the assessment and management of patients with acute coronary syndrome (ACS) and heart failure (HF), cTn is not diagnostically specific for any single myocardial disease process. This narrative review discusses increases in cTn that result from acute and chronic diseases, iatrogenic causes, and myocardial injury other than ACS and HF.

CONTENT

Increased cTn concentrations have been reported in cardiac, vascular, and respiratory disease and in association with infectious processes. In cases involving acute aortic dissection, cerebrovascular accident, treatment in an intensive care unit, and upper gastrointestinal bleeding, increased cTn predicts a longer time to diagnosis and treatment, increased length of hospital stay, and increased mortality. cTn increases are diagnostically and prognostically useful in patients with cardiac inflammatory diseases and in patients with respiratory disease; in respiratory disease cTn can help identify patients who would benefit from aggressive management. In chronic renal failure patients the diagnostic sensitivity of cTn for ACS is decreased, but cTn is prognostic for the development of cardiovascular disease. cTn also provides useful information when increases are attributable to various iatrogenic causes and blunt chest trauma.

SUMMARY

Information on the diagnostic and prognostic uses of cTn in conditions other than ACS and heart failure is accumulating. Although increased cTn in settings other than ACS or heart failure is frequently considered a clinical confounder, the astute physician must be able to interpret cTn as a dynamic marker of myocardial damage, using clinical acumen to determine the source and significance of any reported cTn increase.

The relation between electrocardiographic ST-T changes and NT-proBNP in patients with acute ischemic stroke

BACKGROUND

ST-segment depression and T-wave inversion (ST-T changes) in the electrocardiogram (ECG) and raised levels of natriuretic peptide have been observed in acute ischemic stroke patients. It is unknown whether any relation between ST-T changes and raised levels of natriuretic peptides in patients with an acute ischemic stroke exists.

METHODS

Serial measurements of plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP) and 12-lead ECGs were obtained in 192 consecutive patients with an acute ischemic stroke without ischemic heart disease, atrial fibrillation, heart- or renal failure.

RESULTS

ST-T changes suggestive of myocardial ischemia were observed in the 12 lead ECG of 47 patients (24%). In uni- and multivariate regression analysis after adjustment for age, stroke severity, female sex, systolic blood pressure, diabetes mellitus, and levels of troponin T > 0.03 microg/L, ST-T changes in the ECG remained associated with increased levels of NT-proBNP (beta=76.5, p=0.011).

CONCLUSIONS

ST-T changes suggestive of myocardial ischemia are independently associated with the levels of NT-proBNP in patients with acute ischemic stroke. The clinical importance of this observation remains to be defined.

Clinical prognostic significance of heart abnormality and heart rate variability in patients with stroke

OBJECTIVE

To investigate the difference of heart rate variability (HRV) and serum creatine kinase isoenzyme (CK-MB) activity between right-sided and left-sided stroke, and the relative impact of cardiac autonomic imbalance and heart abnormality on death by serum CK-MB activity and fractal dimension (FD) detection in patients with stroke.

METHODS

Three hundred and twenty-seven patients (mean age: 61.12 +/- 9.74 years) with an acute first-ever stroke underwent a comprehensive clinical investigation and laboratory tests, and were followed up for 1 month. Serum CK-MB activity and FD of heart rate variability were detected on the next day after admission.

RESULTS

During the 1 month follow-up period, 42 out of 327 (12.84%) patients had died. Among all the variables analysed, FD decreased and serum CK-MB activity increased after stroke, and decreased FD was more common in the right-sided stroke. This study also demonstrated that acute phase increased serum CK-MB activity [odds ratio (OR)=0.226, 95% CI: 0.103-0.493, p= 0.000) and decreased FD (OR=0.276, 95% CI: 0.135-0.567, p=0.000) had been linked with the risk of death.

CONCLUSIONS

Right-sided stroke and left-sided stroke had different influences on cardiac autonomic nerve activity. Acute phase increased serum CK-MB activity and decreased FD are well-established prognostic factors of death in patients with stroke. Assessment of FD and serum CK-MB activity may provide additional information on the risk of death in stroke patients.

Neurogenic Pulmonary Oedema Misdiagnosed as Acute Myocardial Infarction in a Comatose Patient

Introduction: We report a case of neurogenic pulmonary oedema (NPO) following massive left cerebral infarct, which was initially misdiagnosed as acute myocardial infarction (AMI). Clinical Picture: This 52-year-old man presented with acute loss of consciousness with normal brain computed tomography (CT). He was treated as non-ST-elevation AMI complicated with pulmonary oedema based on findings of chest radiograph (bilateral pulmonary oedema), electrocardiogram (marked ST-T changes in leads V3 to V6), and cardiac enzymes [elevated creatinine kinase (CK) and CK-MB]. However, coronary angiogram and serial cardiac enzymes were inconclusive. Anisocoria developed after admission and a repeat brain CT was evident for large left cerebral infarct. Treatment: Decompressive craniectomy was carried out. Outcome: Mortality. Conclusions: The diagnosis of NPO can be challenging when it occurs without abnormal findings on preliminary brain CT. It can be mistaken for cardiogenic pulmonary oedema secondary to AMI. Key words: Cerebral infarction, Neurogenic pulmonary oedema, Stroke

Serum troponin in neonatal intensive care

Cardiac troponins have a major role in screening and diagnosis of myocardial ischaemia in adults and children. Their introduction has redefined the diagnosis of myocardial infarction in adults and provided valuable prognostic information. In the paediatric population, troponins show a good correlation with the extent of myocardial damage following cardiac surgery and cardiotoxic medication, and can be used as predictors of subsequent cardiac recovery and mortality. This review discusses the current established reference values in term and preterm infants and demonstrates their potential use in neonatology. They may serve as a useful adjunct in the assessment of the magnitude of myocardial injury in respiratory distress syndrome and asphyxia. They may also benefit centres without on-site echocardiography with some evidence showing good correlation with echo-derived markers of myocardial function. The use of troponins in the neonatal unit remains a research tool. More work is needed to explore their prognostic role and monitoring response to treatment following cardioprotective strategies. In preterm infants the effect of inotropes on myocardial function needs further study and troponin may form an integral part of this research.

Myocardial stress in patients with acute cerebrovascular events

Signs of myocardial involvement are common in patients with acute cerebrovascular events. ST segment deviations, abnormal left ventricular function, increased N-terminal pro-brain natriuretic peptide (NT-proBNP), prolonged QT interval, and/or raised troponins are observed in up to one third of the patients. The huge majority of these findings are fully reversible. The changes may mimic myocardial infarction, but are not necessarily identical to coronary thrombosis. Based on the literature these signs may represent an acute catecholamine release provoked by the cerebrovascular catastrophe itself and not coronary thrombosis. However, all patients with signs of cardiac involvement during acute cerebrovascular events should receive a cardiological follow-up in order to exclude concomitant ischemic heart disease.

Mechanism of troponin elevations in patients with acute ischemic stroke

Ischemic heart disease and cerebrovascular diseases frequently co-exist in the same patient, and similar risk factors are shared. For 60 years, experimental, observational, and clinical trial data have incessantly indicated that neurologically induced myocardial injury exists. Since the introduction of troponin in the diagnosis of acute myocardial infarction, this marker has been measured in a number of other conditions as well. One of these conditions is acute ischemic stroke, causing diagnostic dilemmas for clinicians. Because various electrocardiographic alterations have also been reported in these patients, it has been suggested that elevated troponin levels are somehow neurologically mediated, thus not caused by direct cardiac release. In conclusion, this review examines the available studies that systematically measured troponin in patients with acute ischemic stroke to properly interpret troponin elevations in these patients.

Plasma Troponins as Markers of Myocardial Damage during Cardiac Surgery with Extracorporeal Circulation

All types of cardiac surgery involve considerable injury to the myocardium. However, it is difficult to differentiate, in the immediate post-operative state, between ischemic alterations associated with the cardiac surgery itself and the pathological alterations of a peri-operative myocardial infarction. The diagnosis of damaged myocardium, classically performed with the enzymatic markers creatine kinase (CK) and its muscle fraction (CK-MB), has become more precise with the option of measuring cardiac troponins T and I. We measured these markers in 58 patients undergoing elective cardiac surgery with extra-corporeal circulation (ECC). The patients included 37 cases undergoing valve surgery, 14 for coronary revascularization, 6 for mixed procedures, and 1 for closure of an inter-atrial communication. The markers were measured in plasma at baseline (at anesthesia initiation), 5 min post-ECC commencement, following aorta de-clamping, during the surgical closure, and 6, 18 and 42 hrs after surgery. All the markers were increased significantly relative to the baseline values. Troponin I, CK and CK-MB values peaked between 6 and 18 hrs after surgery, troponin T between 18 and 42 hrs, and myoglobin at the surgical closure. The values of all markers were higher in patients undergoing coronary surgery compared to those in patients undergoing valve surgery. In the evaluation of myocardial damage after surgery, the measurement of classical markers such as CK and myoglobin remain valid, but other markers such as troponins provide significant additional diagnostic benefit and, thus, need to be included in the routine biochemical measurements for monitoring myocardial damage associated with the surgical procedure.

Frequency and significance of troponin T elevation in acute ischemic stroke

Elevated levels of troponin have been reported in patients with acute ischemic stroke. In this prospective study, the prevalence and characteristics of troponin elevation were examined in 244 patients with acute ischemic stroke but without overt ischemic heart disease. Troponin T (TnT) and creatine kinase-MB (CK-MB) concentrations were measured and 12-lead electrocardiograms obtained daily during the first 5 days of admission. Myocardial perfusion scintigraphy was performed in patients with TnT levels of 0.10 micro g/L and in comparable controls without elevation of TnT. Patients were followed for a mean of 19 +/- 7 months, with all-cause mortality as the clinical end point. Elevated levels of TnT (>0.03 micro g/L) and creatine kinase-MB (> or =10 micro g/L) were observed in 10% and 9% of patients, respectively. Patients with elevated TnT had higher frequencies of heart and/or renal failure. Perfusion abnormalities on myocardial perfusion scintigraphy at rest were not more frequent or pronounced in patients with TnT levels of > or =0.10 micro g/L than in the control group. Only 7 patients (3%) had elevations of TnT or creatine kinase-MB and electrocardiographic changes suggesting acute myocardial infarctions. According to univariate and multivariate analyses, elevation of TnT was significantly associated with mortality. In conclusion, elevated levels of TnT are rare in patients presenting with ischemic stroke but without overt ischemic heart disease. Heart and renal failure rather than myocardial infarction are the most likely causes. When present, elevation of TnT seems to be useful in identifying patients who are at increased risk of dying within the following 2 years.

Serum Cardiac Troponin T in Cardiac Amyloidosis: Serial Observations in Five Patients

The most common cause of death of patients suffering from amyloidosis is heart failure and sudden death, and cardiac troponin T (cTnT), a highly specific and sensitive biomarker of myocardial injury, has been reported to be a prognostic marker at presentation. But the relationship between serial measurements of serum cTnT and clinical course of the disease has not been described. An illustrative case was a 55-year-old man with normal renal function presenting with congestive heart failure (CHF), whose initial concentration of cTnT was 0.72 ng/ml. Eight samples of initial endomyocardial biopsy specimens showed the presence of myocyte degeneration and interstitial fibrosis with a small amount of amyloid infiltration. However, the cTnT values remained at 0.69 ng/ml after successful management of CHF, and four months later, a second endomyocardial biopsy revealed diffuse massive amyloid protein deposition. He died of CHF, 9 months after initial presentation. In addition, we present 4 cases of amyloidosis with increased serum cTnT levels. We therefore propose that serial measurements of serum cTnT might be helpful for early diagnosis and prediction of prognosis of patients with amyloidosis.

Transthoracic Echocardiographic Predictors of the Left Atrial Appendage Contraction Velocity in Stroke Patients with Sinus Rhythm

Systemic embolization is a potential complication in patients with thrombi situated in the left atrium and particularly, in the left atrial appendage (LAA). Reduced LAA contraction velocities, determined by the transesophageal echocardiography (TEE), are associated with increased risk of LAA spontaneous echocontrast and thrombus formation, and a history of systemic embolism. However, TEE remains a semi-invasive procedure, limiting its serial application as a screening tool. Therefore, it is desirable to obtain information regarding LAA function by transthoracic echocardiography in patients having cardioembolic stroke. The present study was designed to investigate various echocardiographic variables for patients with stroke to predict LAA dysfunction, reflected as reduced LAA contraction velocity. We studied a total of 61 patients with newly diagnosed acute embolic stroke (42 patients) and transient ischemic attack (19 patients). Computerized tomographic scanning was performed for the diagnosis of embolic stroke. Left atrial functional parameters determined by transthoracic echocardiography, such as left atrial active emptying fraction and acceleration slope of mitral inflow A wave, had significant correlations with the LAA contraction velocity (r = 0.57, p < 0.001; r = 0.54, p < 0.001, respectively). Left atrial volume index, left atrial active emptying volume and left atrial fractional shortening were also correlated with LAA contraction velocity (r = -0.44, p < 0.001; r = 0.38, p = 0.003; r = 0.37, p = 0.004, respectively). In conclusion, transthoracic echocardiography can provide valuable and reliable information about the LAA contraction velocity in stroke patients with sinus rhythm. This finding gives new insights for the appropriate strategy in the evaluation of an acute ischemic stroke.

Avaliação de parâmetros cardíacos em animais com epilepsia: possível causa de morte súbita?

Dentre as causas de morte súbita nas epilepsias (SUDEPE), as disfunções cardíacas têm sido uma área de interesse. Sendo assim, o objetivo de nosso estudo foi avaliar a freqüência cardíaca (FC) (in vivo e in vitro) e a pressão ventricular (PV) in vitro de ratos com epilepsia induzida pela pilocarpina. Ratos machos, adultos, da raça Wistar (n=6) receberam pilocarpina para a indução do status epilepticus. Ratos controles (n=6) receberam solução salina ao invés de pilocarpina. Nossos resultados mostram diferenças significantes na freqüência cardíaca in vivo entre os grupos estudados. Em contraste, não encontramos diferenças entre os grupos nos experimentos in vitro. Nossos resultados sugerem que sob a influência do sistema nervoso central, o coração pode apresentar alterações funcionais que aumentam a probabilidade de ocorrência de morte súbita nas epilepsias.