From the Guidelines
Elevated troponin in the setting of CKD stage 5 is commonly referred to as "chronic troponin elevation" or "troponin elevation due to renal dysfunction". This phenomenon occurs because troponin, a cardiac protein that is normally cleared by the kidneys, accumulates in the bloodstream when kidney function is severely impaired, as noted in the 2021 European Heart Journal study 1. In patients with end-stage renal disease (CKD stage 5), baseline troponin levels are often chronically elevated even in the absence of acute cardiac injury, making the interpretation of troponin values challenging when evaluating for acute coronary syndromes.
When assessing a CKD stage 5 patient with elevated troponin, it's essential to compare the current value with the patient's baseline, look for a rising or falling pattern rather than a single value, and correlate with clinical symptoms and ECG changes, as recommended in the 2021 ESC guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation 1. The elevation is typically modest (often 2-3 times the upper limit of normal) in chronic renal dysfunction, whereas acute cardiac events may cause more dramatic increases or a rising pattern.
Key considerations in the management of these patients include:
- Assessing kidney function by eGFR for prognostic reasons and to identify patients at risk of contrast-induced nephropathy 1
- Using high-sensitivity troponin assays, which maintain high diagnostic and prognostic accuracy in patients with renal dysfunction, with a threshold of <5 ng/L potentially ruling out myocardial injury in this population 1
- Carefully selecting and dosing antithrombotic drugs due to the increased risk of bleeding in patients with CKD, with particular caution for patients with stage 5 CKD (eGFR <15 mL/min/1.73 m2) where safety and efficacy data for P2Y12 receptor inhibitors are insufficient 1.
From the Research
Elevated Troponin in CKD Stage 5
Elevated troponin levels in the setting of chronic kidney disease (CKD) stage 5 can be attributed to various factors. Some key points to consider include:
- Elevated troponin levels are often seen in patients with heart failure, and their predictive value can be affected by comorbidities such as renal dysfunction 2
- High-sensitivity cardiac troponins T (hs-cTnT) and I (hs-cTnI) are independent predictors of cardiovascular mortality in acute heart failure (AHF), even after adjusting for renal function 2
- The role of troponin in predicting heart failure readmissions remains inconsistent, particularly in those with advanced renal impairment 2
Troponin Elevation in CKD
Some studies have investigated the relationship between troponin elevation and CKD:
- A case study presented a rare instance of persistent troponin elevation in a patient with chronic heart failure 3
- Another study discussed the use of beta-blockers in the management of hypertension and/or CKD, highlighting the importance of renin-angiotensin system blockers in achieving renal protection 4
- A report from the Chronic Renal Insufficiency Cohort (CRIC) study found that persistent high serum bicarbonate was associated with an increased risk of heart failure in patients with CKD 5
Key Considerations
When evaluating elevated troponin levels in CKD stage 5, consider the following:
- The prognostic significance of troponin adjusted for renal function in patients with heart failure 2
- The potential for troponin elevation to be a marker of cardiovascular mortality in AHF, even in the presence of advanced renal impairment 2
- The need for further studies to determine the optimal range of serum bicarbonate in CKD to prevent adverse clinical outcomes 5