Correlation of Brain Natriuretic Peptide Levels in Patients With Severe Aortic Stenosis Undergoing Operative Valve Replacement or Percutaneous Transcatheter Intervention With Clinical, Echocardiographic, and Hemodynamic Factors and Prognosis

Study Questions:

Is there a relationship between B-type natriuretic peptide (BNP), aortic stenosis (AS) severity, and prognosis?

Methods:

A cohort of 289 high-risk patients with severe AS who were referred for transcatheter aortic valve replacement (TAVR) was divided into tertiles based on BNP level: level I (n = 96), level II (n = 95), and level III (n = 98). Group III patients were more symptomatic, had higher Society of Thoracic Surgeons and EuroSCORE scores, and had a greater prevalence of renal failure, atrial fibrillation, and previous myocardial infarction; lower ejection fraction and cardiac output; and higher pulmonary pressure and left ventricular end-diastolic pressure.

Results:

The degree of AS did not differ among the three groups. Stepwise forward multiple regression analysis identified ejection fraction and pulmonary artery systolic pressure as independent correlates with plasma BNP. Mortality rates during a median follow-up of 319 days (range 110-655 days) were significantly lower in patients from Group I compared with Groups II and III (p < 0.001). However, after multivariable adjustment, the strongest correlates for mortality were renal failure (hazard ratio [HR], 1.44; p = 0.05) and absence of surgical AVR or TAVR (HR, 2.2; p < 0.001). Mean BNP decreased immediately after aortic balloon valvotomy from 1,595–1,229 to 1,252–1,076 (p = 0.001); yet increased to 1,609–1,264 (p = 0.9) at 1-12 months. After surgical AVR, there was a nonsignificant, immediate decrease in BNP from 928–1,221 to 896–1,217 (p = 0.77), continuing up to 12 months: 533–213 (p = 0.08). After TAVR, there was no significant decrease in BNP immediately after the procedure; however, at 1 year, the mean BNP level decreased significantly from 568–582 to 301–266 pg/dl (p = 0.03).

Conclusions:

The authors concluded that elevated BNP in high-risk patients with severe AS is not an independent marker for higher mortality, and that BNP level was not significantly associated with the AS severity, but did reflect heart failure status.

Perspective:

BNP is a marker of systolic and diastolic dysfunction, and a strong predictor of mortality in patients with heart failure. Previous studies have found a correlation between BNP and AS severity, and between BNP and prognosis among patients with AS. Absence of correlation in this study between BNP and AS severity probably is because all patients (having been referred for TAVR) presumably had severe or very severe symptomatic AS. Absence of correlation in this study between BNP and mortality likely is due to definitive intervention in some, but not all patients. After definitive intervention for severe symptomatic AS, pre-intervention BNP has no post-intervention prognostic importance.

Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Cardiac Surgery and Heart Failure, Acute Heart Failure, Heart Failure and Cardiac Biomarkers

Keywords: Heart Valve Prosthesis, Myocardial Infarction, Multivariate Analysis, Cardiac Output, Blood Pressure, Pulmonary Artery, Hemodynamics, Receptors, Opioid, delta, Heart Diseases, Renal Insufficiency, Balloon Valvuloplasty, Biological Markers, Heart Failure, Natriuretic Peptide, Brain


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