RESUMO
AIMS: We investigated whether the addition of left atrial (LA) size determined by echocardiography improves cardiovascular risk prediction in young adults over and above the clinically established Framingham 10-year global CV risk score (FRS). METHODS AND RESULTS: We included white and black CARDIA participants who had echocardiograms in Year-5 examination (1990-91). The combined endpoint after 20 years was incident fatal or non-fatal cardiovascular disease: myocardial infarction, heart failure, cerebrovascular disease, peripheral artery disease, and atrial fibrillation/flutter. Echocardiography-derived M-mode LA diameter (LAD; n = 4082; 149 events) and 2D four-chamber LA area (LAA; n = 2412; 77 events) were then indexed by height or body surface area (BSA). We used Cox regression, areas under the receiver operating characteristic curves (AUC), and net reclassification improvement (NRI) to assess the prediction power of LA size when added to calculated FRS or FRS covariates. The LAD and LAA cohorts had similar characteristics; mean LAD/height was 2.1 ± 0.3 mm/m and LAA/height 9.3 ± 2.0 mm(2)/m. After indexing by height and adjusting for FRS covariates, hazard ratios were 1.31 (95% CI 1.12, 1.60) and 1.43 (95% CI 1.13, 1.80) for LAD and LAA, respectively; AUC was 0.77 for LAD and 0.78 for LAA. When LAD and LAA were indexed to BSA, the results were similar but slightly inferior. Both LAD and LAA showed modest reclassification ability, with non-significant NRIs. CONCLUSION: LA size measurements independently predict clinical outcomes. However, it only improves discrimination over clinical parameters modestly without altering risk classification. Indexing LA size by height is at least as robust as by BSA. Further research is needed to assess subgroups of young adults who may benefit from LA size information in risk stratification.
Assuntos
Doenças Cardiovasculares/epidemiologia , Átrios do Coração/diagnóstico por imagem , Adulto , Doenças Cardiovasculares/diagnóstico por imagem , Ecocardiografia , Feminino , Humanos , Incidência , Entrevistas como Assunto , Masculino , Tamanho do Órgão , Valor Preditivo dos Testes , Medição de Risco , Estados Unidos/epidemiologiaRESUMO
BACKGROUND: Framingham risk score (FRS) underestimates risk in young adults. Left ventricular mass (LVM) relates to cardiovascular disease (CVD), with unclear value in youth. In a young biracial cohort, we investigate how FRS predicts CVD over 20 years and the incremental value of LVM. We also explore the predictive ability of different cut-points for hypertrophy. METHODS: We assessed FRS and echocardiography-derived LVM (indexed by body surface area or height2.7) from 3980 African-American and white Coronary Artery Risk Development in Young Adults (CARDIA) participants (1990-1991); and followed over 20 years for a combined endpoint: cardiovascular death; nonfatal myocardial infarction, heart failure, cerebrovascular disease, and peripheral artery disease. We assessed the predictive ability of FRS for CVD and also calibration, discrimination, and net reclassification improvement for adding LVM to FRS. RESULTS: Mean age was 30±4 years, 46% males, and 52% white. Event incidence (n=118) across FRS groups was, respectively, 1.3%, 5.4%, and 23.1% (p<0.001); and was 1.4%, 1.3%, 3.7%, and 5.4% (p<0.001) across quartiles of LVM (cut-points 117 g, 144 g, and 176 g). LVM predicted CVD independently of FRS, with the best performance in normal weight participants. Adding LVM to FRS modestly increased discrimination and had a statistically significant reclassification. The 85th percentile (≥116 g/m2 for men; ≥96 g/m2 for women) showed event prediction more robust than currently recommended cut-points for hypertrophy. CONCLUSION: In a biracial cohort of young adults, FRS and LVM are helpful independent predictors of CVD. LVM can modestly improve discrimination and reclassify participants beyond FRS. Currently recommended cut-points for hypertrophy may be too high for young adults.