Heart failure–related volume overload
Unilateral or bilateral lower-extremity edema with an elevated BNP most commonly reflects heart failure with increased cardiac filling pressures and fluid retention. [1] Elevated BNP supports or helps exclude heart failure as the cause of symptoms in dyspnea presentations, but BNP is not specific for heart failure because multiple cardiac and noncardiac conditions can elevate BNP. [1]
Most likely diagnoses to prioritize
Heart failure with fluid retention causing peripheral edema is most likely in the setting of an elevated BNP. [1] Unilateral edema should also trigger evaluation for deep vein thrombosis (DVT) because DVT can coexist with, mimic, or precipitate cardiopulmonary decompensation. [2] Pulmonary embolism and right-sided heart failure syndromes should be considered when BNP is elevated and lower-extremity edema is present, including when edema is unilateral. [1]
Work-up for elevated BNP and lower-extremity edema
A history and physical examination should be performed to assess volume status and identify cardiac and noncardiac contributors. [1] BNP measurement is recommended to support or exclude heart failure in dyspnea presentations. [1] A chest x-ray should be obtained in suspected or new-onset HF or acute decompensated HF to assess heart size, pulmonary congestion, and alternative causes. [1] Transthoracic echocardiography (TTE) should be performed during initial evaluation to assess cardiac structure and function. [1] Additional baseline evaluation should include identification of other conditions that can raise BNP, including acute coronary syndrome, atrial fibrillation, valvular heart disease, pericardial disease, myocarditis, renal failure, and sepsis. [1] If unilateral edema or other DVT features are present, venous thromboembolism evaluation should be performed using a clinical prediction framework followed by proximal leg vein ultrasound when indicated. [2]
Treatment of suspected heart failure–related congestion
Diuretics are recommended to relieve congestion, improve symptoms, and prevent worsening heart failure in patients with fluid retention. [1] For ongoing congestive symptoms, intensification with additional diuretic strategies should be reserved for patients who do not respond to moderate- or high-dose loop diuretics to minimize electrolyte abnormalities. [1] When hospitalized with evidence of significant fluid overload, intravenous loop diuretics should be administered promptly to improve symptoms and reduce morbidity. [1] Congestion-directed diuretic therapy should be titrated with a goal to resolve clinical evidence of congestion to reduce symptoms and rehospitalizations. [1]
Medication selection algorithm for acute edema with elevated BNP
Loop diuretics should be selected as initial decongestive therapy for volume-overload edema in suspected heart failure. [1] A thiazide-type diuretic strategy (for example, metolazone as an add-on) should be reserved for inadequate response to moderate- or high-dose loop diuretics. [1] Additional guideline-directed heart failure therapy should be initiated after confirmation and phenotyping based on TTE and clinical classification of ejection fraction and clinical severity. [1]
Initiation thresholds and referral triggers
An elevated BNP should prompt evaluation for suspected heart failure and initiation of the diagnostic pathway for HF confirmation and classification. [1] For suspected chronic heart failure pathways that use natriuretic peptides, specialist assessment and echocardiography are guided by NT-proBNP thresholds, including NT-proBNP between 400 and 2,000 ng/L, which should trigger specialist assessment and TTE within 6 weeks. [3]
Common pitfalls to avoid
Assuming elevated BNP is specific for heart failure should be avoided because BNP can be elevated in acute coronary syndrome, atrial fibrillation, valvular disease, pericardial disease, myocarditis, and in noncardiac illnesses such as renal failure and sepsis. [1] With unilateral edema, omission of DVT evaluation should be avoided because DVT diagnosis pathways rely on clinical probability assessment followed by proximal venous ultrasound when indicated. [2]
Goals of therapy
Decongestive treatment should aim for resolution of clinical evidence of congestion to reduce symptoms and rehospitalizations. [1]