Physiology: likely multifactorial, due to myocardial necrosis/apoptosis, myocardial stress due to the tachycardia, an underlying inflammatory/fibrotic process, myocardial dysfunction due to variations in atrial/ventricular volume and pressure load, and/or coronary microembolism
Aortic Stenosis (AS) (see Aortic Stenosis, [[Aortic Stenosis]]): in patients with aortic valve disease, elevated troponin levels are associated with greater degrees of left ventricular wall thickness and higher pulmonary artery systolic pressures (Int J Cardiol, 2003) [MEDLINE]
Hypertensive Heart Disease (see Hypertension, [[Hypertension]])
Methamphetamine Intoxication (see Methamphetamine, [[Methamphetamine]])
Physiology: due to adrenergic effects
Myocardial Injury without Ischemia
Chronic Kidney Disease (CKD)/ESRD (see Chronic Kidney Disease, [[Chronic Kidney Disease]]): unknown mechanism (possibly related to impaired renal troponin clearance)
Physiology
Potential Physiologic Mechanisms of Troponin Elevation in CKD
Cardiac Injury Associated with Chronic Structural Heart Disease, Such as Coronary Artery Disease or Heart Failure (Rather than Acute Myocardial Ischemia)
Decreased Renal Clearance of Troponin: however, there is controversy as to whether this is the primary mechanism of increased troponin in patients with CKD (J Am Coll Cardiol, 2012) [MEDLINE]
Clinical Data
Troponin Elevation in Patients without Suspected Acute Coronary Syndrome (ACS)
In Systematic Review and Meta-Analysis in Patients with CKD on Dialysis and without Suspected Acute Coronary Syndrome, Troponin Elevation was Associated with Increased All-Cause Mortality and Increased Cardiovascular Mortality (Ann Intern Med, 2014) [MEDLINE]
Hazard Ratio for All-Cause Mortality for Troponin T: 3.0 (95% CI, 2.4 to 4.3)
Hazard Ratio for All-Cause Mortality for Troponin I: 2.7 (CI, 1.9 to 4.6)
Hazard Ratio for Cardiovascular Mortality for Troponin T: 3.3 (CI, 1.8 to 5.4)
Hazard Ratio for Cardiovascular Mortality for Troponin I: 4.2 (CI, 2.0 to 9.2)
In Systematic Review and Meta-Analysis in Patients with CKD Not on Dialysis and without Suspected Acute Coronary Syndrome, Troponin Elevation was Associated with Increased All-Cause Mortality and Increased Cardiovascular Mortality (Ann Intern Med, 2014) [MEDLINE]
All-Cause Mortality and Cardiovascular Mortality Findings were Likewise Increased in CKD Patients Not on Dialysis (Similar to That Above for CKD Patients on Dialysis, But There Were Fewer Studies in This Analysis
Troponin Elevation in Patients with Suspected Acute Coronary Syndrome (ACS)
In Systematic Review and Meta-Analysis in Patients with CKD and Suspected Acute Coronary Syndrome, Troponin Levels Can Aid in the Identification of Patients with Poor Prognosis, But the Diagnostic Utility is Impaired by Varying Estimates of Sensitivity/Specificity (Ann Intern Med, 2014) [MEDLINE]
Sensitivity of Troponin T for Diagnosis of ACS: 71-100%
Specificity of Troponin T for Diagnosis of ACS: 31-86%
Sensitivity of Troponin I for Diagnosis of ACS: 43-94%
Specificity of Troponin I for Diagnosis of ACS: 48-100%
Elevated Troponin T or I was Associated with Higher Risk for Short-Term Mortality and Cardiac Events
A Similar Trend for Long-Term Mortality was Found for Troponin I, But There Was Less Evidence for Long-Term Cardiac Events for Troponin T and I
Patients with Advanced CKD Tended to Have Worse Prognosis with Elevated Troponin I Levels Than Those Without Elevated Troponin I Levels
Recommendations
A Change in Troponin Level >20% within 9 hrs (With 1 Value Exceeding the 99th Percentile) is Recommended for Acute MI Diagnosis in Patients with End-Stage Renal Disease and Suspected ACS (Clin Chem, 2007) [MEDLINE]
In One Study, 27% of Patients with Acute Stroke Had Elevated Troponin I Levels (Tidsskr Nor Laegeforen, 2001) [MEDLINE]
Physiology: likely due to an imbalance in the autonomic nervous system, with excessive sympathetic activity and an increased catecholamine effect on myocardial cells
Intracerebral Hemorrhage (Hemorrhagic Cerebrovascular Accident) (see Intracerebral Hemorrhage, [[Intracerebral Hemorrhage]])
Physiology: likely due to an imbalance in the autonomic nervous system, with excessive sympathetic activity and an increased catecholamine effect on myocardial cells
Hunt-Hess Grade of SAH is Correlated with the Degree of Myocardial Necrosis After SAH (Stroke, 2004) [MEDLINE]
Troponin I Elevation After SAH is Associated with an Increased Risk of Cardiopulmonary Complications, Delayed Cerebral Ischemia, and Death or Poor Outcome at Discharge (Circulation, 2005) [MEDLINE]
Physiology: likely due to an imbalance in the autonomic nervous system, with excessive sympathetic activity and an increased catecholamine effect on myocardial cells
Strenuous Exercise
Epidemiology
Marathon Runners
Physiology: due to ventricular stretch
Clinical Data
Troponin T and I Elevations are Common in Maraton Runners Immediately After the Race, Occurring in >80% of Runners (Am J Cardiol., 2012) [MEDLINE]
Immediately After the Race, Approximately 8% of the Runners Had a Troponin Elevation in the Reference Range for Myocardial Infarction
By 24 hrs After the Race, All Runners Had Normal Troponin Levels
Epidemiology: troponin elevation may occur in acute pericarditis (Am J Cardiol, 2001) [MEDLINE]
Physiology: due to inflammation
Acute Respiratory Failure (see Respiratory Failure, [[Respiratory Failure]])
Physiology:
Burns (>25% Body Surface Area) (see Burns, [[Burns]])
Epidemiology
Increase in Troponin in Burn Patients is Related to the Extent of Burns Rather than Age, Underlying Medical Conditions, or the Administration of Resuscitation Fluid ( J Trauma, 1998) [MEDLINE]
Epidemiology: troponin elevation tends to be associated with advanced heart failure and worse prognosis
Physiology: due to myocardial strain and/or myocyte death
Diabetes Mellitus with Stable Coronary Artery Disease
Physiology: xxxx
Clinical Data
Bypass Angioplasty Revascularization Investigation in Type 2 Diabetes (BARI 2D) Trial of High-Sensitivity Troponin Assay (NEJM, 2015) [MEDLINE]: n= 85 patients who had both type 2 diabetes and stable ischemic heart disease
Approximately 99.6% of Patients with Both NIDDM and Stable Ischemic Heart Disease Had Detectable (≥3 ng/L) Troponin T Levels
Approximately 39.3% of Patients with Both NIDDM and Stable Ischemic Heart Disease Had Abnormal Baseline Troponin T Levels (Above the Upper Reference Limit Which Defined Myocardial Injury)
In Patients with Both NIDDM and Stable Ischemic Heart Disease, Elevated Baseline Troponin T Level Correlated with Increased Risk of Death from Cardiovascular Disease, Myocardial Infarction, and Stroke at 5 Years: risk was 27% (double that of the group with normal baseline troponin T levels)
An Abnormal Troponin T of ≥14 ng/L Did Not Identify a Subgroup of Patients Who Benefited from Random Assignment to Prompt Coronary Revascularization
Elevations of cardiac troponin I associated with myocarditis. Experimental and clinical correlates. Circulation. 1997;95(1):163 [MEDLINE]
Evaluation of troponin-I as an indicator of cardiac dysfunction after thermal injury. J Trauma. 1998;45(4):700 [MEDLINE]
Elevation of serum cardiac troponin I in noncardiac and cardiac disease other than acute coronary syndromes. Am J Emerg Med. 1999;17:225–229 [MEDLINE]
[Myocardial injury in acute stroke assessed by troponin I]. Tidsskr Nor Laegeforen. 2001;121(4):421 [MEDLINE]
Circulating cardiac troponin I in acute pericarditis. Am J Cardiol. 2001;87(11):132 [MEDLINE]
Cardiac troponin I in patients with severe exacerbation of chronic obstructive pulmonary disease. Intensive Care Med. 2003;29(4):584 [MEDLINE]
Troponin-I elevation in patients with increased left ventricular mass. Am J Cardiol. 2003;92(1):88 [MEDLINE]
Cardiac troponin I in aortic valve disease. Int J Cardiol. 2003;89(2-3):281 [MEDLINE]
Predictors of neurocardiogenic injury after subarachnoid hemorrhage. Stroke. 2004;35(2):548. Epub 2004 Jan 22 [MEDLINE]
Cardiac troponin elevation, cardiovascular morbidity, and outcome after subarachnoid hemorrhage. Circulation. 2005;112(18):2851 [MEDLINE]
National Academy of Clinical Biochemistry laboratory medicine practice guidelines: use of cardiac troponin and B-type natriuretic peptide or N-terminal proB-type natriuretic peptide for etiologies other than acute coronary syndromes and heart failure. Clin Chem. 2007;53:2086-96 [MEDLINE]
Diseased skeletal muscle: a noncardiac source of increased circulating concentrations of cardiac troponin T. J Am Coll Cardiol. 2011;58(17):1819 [MEDLINE]
CCF 2012 expert consensus document on practical clinical considerations in the interpretation of troponin elevations: a report of the American College of Cardiology Foundation Task Force on Clinical Expert Consensus Documents. J Am Coll Cardiol. 2012;60:2427-63 [MEDLINE]
Cardiac troponins in young marathon runners. Am J Cardiol. 2012;110:594–598 [MEDLINE]
Role of troponin in patients with chronic kidney disease and suspected acute coronary syndrome: a systematic review. Ann Intern Med. 2014 Oct 7;161(7):502-12. doi: 10.7326/M14-0746 [MEDLINE]
Prognostic value of cardiac troponin in patients with chronic kidney disease without suspected acute coronary syndrome: a systematic review and meta-analysis. Ann Intern Med. 2014 Oct 7;161(7):491-501. doi: 10.7326/M14-0743 [MEDLINE]
Troponin and cardiac events in stable ischemic heart disease and diabetes. N Engl J Med. 2015;373:610–620 [MEDLINE]
