Can shortness of breath (SOB) cause elevated troponin levels?

Shortness of Breath Can Cause Elevated Troponin Levels

Yes, shortness of breath (SOB) can cause elevated troponin levels through various mechanisms, particularly when associated with conditions that cause myocardial stress or injury without coronary artery occlusion. 1, 2

Mechanisms of Troponin Elevation in Respiratory Conditions

• Acute respiratory failure can cause hypoxemia leading to myocardial injury and troponin elevation 1, 2
• Pulmonary embolism can cause right ventricular strain, leading to troponin release despite patent coronary arteries 1
• Severe respiratory distress can create an oxygen supply-demand imbalance in the myocardium, resulting in type 2 myocardial infarction 2
• Tachycardia and increased cardiac demand during respiratory exacerbations can cause myocardial stress and subsequent troponin release 2

Clinical Significance of Troponin Elevation in SOB

• Troponin elevation in pulmonary embolism is associated with worse prognosis and higher mortality rates 1
• The prevalence of positive troponin T in pulmonary embolism ranges from 0-35% in non-massive PE to 50% in clinically massive PE 1
• Elevated troponin in respiratory conditions may indicate right ventricular dysfunction rather than coronary artery disease 1
• Troponin elevation in respiratory failure reflects myocardial injury but does not necessarily indicate myocardial infarction 1

Interpreting Troponin Elevation in SOB

• Solitary elevations of troponin cannot be assumed to be due to myocardial infarction 1
• For diagnosis of acute myocardial infarction, evidence of myocardial ischemia is required in addition to troponin elevation 1
• In patients with SOB but without chest pain or ECG changes, troponin elevation is more likely due to non-coronary causes 2
• Mild troponin elevations (<2-3 times upper limit of normal) in patients with respiratory conditions generally do not require workup for type 1 MI unless strongly suggested by clinical symptoms or ECG changes 2

Specific Respiratory Conditions Associated with Troponin Elevation

• Pulmonary embolism: Transmural RV infarction despite patent coronary arteries has been found in autopsies of patients who died of massive PE 1
• Pulmonary hypertension: Can cause chronic right heart strain, resulting in troponin elevation 2
• Pneumonia and respiratory infections: Can cause troponin elevation through hypoxemia and inflammatory responses 2
• COVID-19 infections: 5-25% of hospitalized patients had troponin elevations, with higher prevalence in those admitted to intensive care units 2

Clinical Approach to Troponin Elevation in SOB

• Interpret troponin in clinical context, considering respiratory symptoms, ECG changes, and risk factors 2
• Serial measurements are essential, as a single elevated value is insufficient for diagnosis 1
• For patients with elevated troponin and respiratory symptoms but without evidence of ACS, focus on treating the underlying respiratory condition 2
• Consider echocardiography to assess for right ventricular dysfunction, especially in suspected pulmonary embolism 1

Pitfalls and Caveats

• Falsely elevated troponin values can occur due to interference with troponin assays, such as from heterophile antibodies 3
• Troponin elevations may persist for up to 14 days after myocardial injury, complicating interpretation of serial measurements 1
• Point-of-care troponin tests have substantially lower sensitivity than central laboratory methods 2
• In patients with end-stage renal disease, troponin elevations are common even without clinical evidence of ACS 1