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1. Will BNP or NT pro-BNP prove useful in identifying patients with heart failure in Primary Care ? Dr Ahmet Fuat Darlington & The Dales PCTs Darlington Memorial Hospital Bishop Auckland General Hospital

4. Natriuretic Peptides

5. Natriuretic Peptides: Origin and Stimulus of Release Adapted from Burnett JC, J Hypertens 2000;17(Suppl 1):S37-S43 ANP = Atrial Natriuretic Peptide BNP = B-type Natriuretic Peptide CNP = C-type Natriuretic Peptide Peptide Primary Origin Stimulus of Release ANP Cardiac atria Atrial distension BNP Ventricular myocardium Ventricular overload CNP Endothelium Endothelial stress

6. Release of BNP from Cardiac Myocytes myocyte preproBNP (134 aa) proBNP (108 aa) signal peptide (26 aa) secretion NT-proBNP (1-76) BNP (77-108)

8. Clinical Potential of BNP / NT-proBNP Has already been extensively studied! Diagnosis- raised in those with LVSD/AF/ LVH Normal BNP makes LVSD very unlikely NEGATIVE PREDICTIVE VALUE Prognosis- of patients with heart failure Therapy- monitor efficacy Treatment- ?

9. WHY IS IT NOT BEING USED? 1. Previous studies used “in-house” assays - Two now commercially available - BNP + NT proBNP. Which to use? 2. What cut off should be used (Bayesian model)? Companies report 97.5 percentile in volunteers up to 65! 3. Can medication “normalize” the level? 4. Where does it fit with other tests etc? 5. Will we be swamped? 6. Will it be cost effective?

11. Aims & Methodology Aims To compare the 2 assays directly in comparison to the “gold standard”: assessment of LV function by echo criteria To identify appropriate “cut-off” point for assays To plan “rollout” of BNP in primary care Methods & Setting Patients from primary care with suspected HF are referred to one-stop clinics at DMH & BAGH – all have bloods, ECG, CXR, BNP, NT pro-BNP & Echo S can performed by BSE accredited senior technician LV function assessed by “eye-ball”, Simpson’s rule, wall motion score Sensitivity, specificity and ROC used to calculate AUC, NPV and PPV for each assay

12. Preliminary data 280 consecutive patients have been seen and studied Data has been assessed for 120 Age: Me a n 74 yrs (Range 39-93) Sex: 44 Males 76 Females LVSD present in 44 / 120 (37%)

13. BNP (Biosite) Negative predictive value at: pg/ml NPV % false / all negatives 20 78.9 4/19 40 88.2 6/51 50 87.7 7/57 60 86.9 8/61 80 86.3 10/73 100 82.2 14/79

14. NT pro-BNP (Roche) Negative predictive value at: pg/ml NPV % fa lse/all negatives 50 87.5 1/8 100 95.5 1/22 125 96.7 1/30 150 97.3 1/37 175 93.0 3/43 200 91.5 4/47

16. CONCLUSIONS Only a minority of patients referred to HF clinic had LVSD. In the real-life setting, NT pro-BNP performed better than BNP. A satisfactory cut-off has been identified (needs validating). NT pro-BNP could be used to select referrals to a HF clinic or for echocardiography. This hypothesis needs testing in real life GP

17. Suspected Heart Failure in Primary Care – the Utility of B-Type Natriuretic Peptide ( NT pro-BNP) as a Pre-screening Test for Secondary Care Referral – a Real Life Study Darlington & Bishop Auckland