[Screening of asymptomatic left ventricular systolic dysfunction in a population sample at high cardiovascular risk...

Prevalence of asymptomatic left ventricular systolic dysfunction (ALVSD) increases with age and cardiovascular (CV) risk exposure. Early diagnosis and treatment allow reducing heart failure and fatal and non-fatal event rates. Data on ALVSD prevalence in Italy are still scarce and ALVSD remains commonly under-diagnosed in primary care, where diagnostic facilities are limited. Among subjects at high CV risk in primary care, we assessed the prevalence of ALVSD and the relative predictive value of N-terminal pro-brain natriuretic peptide (NT-proBNP) and the Framingham Heart Failure Risk Score (FHFRS).

Records of 4047 subjects aged 55-80 years, without history, symptoms or signs of heart failure, registered at three primary care practices in Lombardy, Northern Italy, were reviewed; 623 subjects at high CV risk underwent visit, ECG, echocardiography, NT-proBNP and FHFRS calculation.

ALVSD, defined as left ventricular ejection fraction <50%, was detected in 33 subjects (5.3%) who showed higher NT-proBNP (p<0.001) and FHFRS (p=0.013) than those without ALVSD. NT-proBNP levels beyond normal age and gender-specific 95th percentile had a 97.7% negative predictive value for ALVSD and were associated with a 6-fold increase in ALVSD risk. Adding NT-proBNP to FHFRS significantly improved prediction (C-statistic 0.76, 95% confidence interval [CI] 0.67-0.84 vs 0.63, 95% CI 0.53-0.73, p=0.04; net reclassification improvement 38.4%). The combination of FHFRS and major ECG abnormalities was not superior to stand alone NT-proBNP (C-statistic 0.71, 95% CI 0.63-0.80 vs 0.74, 95% CI 0.64-0.83, p=0.61).

In subjects at high CV risk in primary care, prevalence of ALVSD is 5.3%; for diagnosis NT-proBNP adds predictive value to the FHFRS and is equivalent to the combination of FHFRS and ECG. Because of its practical advantages, NT-proBNP might be routinely used for ALVSD screening in primary care.