From the Guidelines
An NT-proBNP level of 1214 ng/L in an 85-year-old woman is considered elevated and warrants further investigation, even in the absence of obvious volume overload. According to the American Heart Association, partition values for diagnostic criteria of NT-proBNP ≥800 pg/mL have been suggested to support the diagnosis of heart failure with preserved ejection fraction (HFpEF) 1. Given that age-adjusted normal values for NT-proBNP increase with age, and for individuals over 75 years, levels up to 450-900 ng/L may be acceptable, a level of 1214 ng/L exceeds typical age-adjusted thresholds.
Further cardiac evaluation is recommended, including:
- An echocardiogram to assess cardiac function, structure, and potential HFpEF, which can present without obvious fluid overload
- A thorough medication review
- Assessment of renal function, as kidney disease can elevate NT-proBNP
- Evaluation for other conditions like atrial fibrillation or pulmonary hypertension
The elevated level may indicate subclinical cardiac stress before overt symptoms appear, making investigation important for early intervention. Clinical context remains crucial, as NT-proBNP can be affected by various factors including age, renal function, and body mass. It's also worth noting that factors independent of left ventricular diastolic pressure and diastolic stress may affect BNP levels in patients with HFpEF, and partition values may need to be adjusted in patients with HFpEF and significant comorbid states 1.
From the Research
NT ProBNP Levels in Elderly Women
- An NT ProBNP level of 1214 ng/L in an 85-year-old woman is considered elevated, as the upper reference level (URL) for women aged 80+ years is 1276 ng/L 2.
- Elevated NT ProBNP levels are associated with increased probability of congestive heart failure (CHF) and atrial fibrillation (AF), and are a predictor of poor prognosis 3, 4.
- The European Society of Cardiology recommends a cut-off of 125 ng/L for the diagnosis of heart failure in ambulatory settings, but this cut-off may not be suitable for elderly women 2.
Clinical Implications
- Elderly individuals with NT ProBNP levels ≥900 ng/L constitute a population at high cardiovascular risk, even in the absence of diagnosed CHF or AF, and therefore merit further investigation 3.
- High NT ProBNP levels are associated with poor exclusionary performance for mild degrees of systolic dysfunction and for diastolic dysfunction, limiting its utility as a rule-out test for LV dysfunction in very old people with limiting dyspnoea 5.
- Incorporating history of myocardial infarction as an additional referral prompt may slightly reduce the number of cases missed, but at the expense of higher echocardiography and false positive rates 5.
Further Investigation
- Further investigation is warranted in this patient, as elevated NT ProBNP levels are associated with increased cardiovascular risk and poor prognosis 3, 4.
- Echocardiography and other diagnostic tests may be necessary to determine the underlying cause of the elevated NT ProBNP level and to guide treatment decisions 5, 3.