Abstract 18343: B-type Natriuretic Peptide (BNP) Levels Correlate With Indices of Left Ventricular Function and Predict Outcomes Following Transcatheter Aortic Valve Implantation (TAVI): A Cardiovascular Magnetic Resonance Imaging Study

Abstract

Background: High levels of B-type natriuretic peptide (BNP) have been shown to predict outcomes following transcatheter aortic valve implantation (TAVI). However, the relationship between pre-procedural BNP levels and magnetic resonance imaging (MRI) parameters of cardiac function has not previously been described in patients with severe aortic stenosis undergoing TAVI. Methods: 108 patients underwent cardiac MRI and had measurements of BNP taken prior to TAVI. MRI was performed using a 1.5T scanner; steady-state free precession sequences were used for aortic valve planimetry and to assess ventricular volumes and mass. Gadolinium enhancement was assessed after injection of 0.1 mmol/kg of gadolinium contrast agent. Semi-automated image analysis was performed by two specialist reviewers blinded to patient treatment. Results: The mean age of the population studied was 79 years (IQR 74-85); mean follow-up was 805 days (IQR 368-1025). The mean BNP level was 698 ng/l (range 14-6048); univariate linear regression showed significant relationships between BNP and left ventricular (LV) ejection fraction (p&lt;0.0001), end diastolic volume (p=0.001), end systolic volume (p&lt;0.0001), and indexed mass (p=0.012). Median BNP levels were lower in patients who survived than in those who died (287ng/l vs. 560ng/l; p=0.099); ROC curve analysis found a BNP level of &gt;170ng/l to be the optimal cutoff for the prediction of all-cause mortality. Survival curve analysis showed a significantly increased risk of all-cause mortality in patients with BNP&gt;170ng/l and MRI LV ejection fraction &lt;50% (Hazard ratio 5.72, p=0.015; Figure). Conclusions: In patients with severe aortic stenosis undergoing TAVI, BNP levels are closely correlated with LV function, indexed LV mass, and both end-systolic and end-diastolic volumes, as measured by MRI. Patients with BNP&gt;170ng/l and MRI LV ejection fraction&lt;50% are at significantly higher risk of death following TAVI. </jats:p