Abstract 2410: Coronary Calcification, LDL Cholesterol and Systolic Blood Pressure: A Synergistic Interaction
Introduction: Numerous studies have proposed atherosclerotic deposition of LDL cholesterol (LDL-C) may require previous damage to the endothelium by factors such as hypertension. In this study we sought evaluate the ‘response-to-injury hypothesis’ of atherosclerosis by assessing the interaction between systolic blood pressure (SBP) and LDL-C in predicting presence of coronary artery calcification (CAC) in asymptomatic men.
Method: We studied 559 asymptomatic men (46±7 yrs) who were referred for electron-beam tomography (EBT) in San Paulo, Brazil. The prevalence of CAC was determined across LDL-C tertiles (1st: <115 mg/dl, 2nd: 115–139 mg/dl, 3rd: ≥140 mg/dl) within tertiles of SBP: low (100 –120 mm Hg), middle (121–130 mm Hg), and high (131–190 mm Hg).
Results: Overall, 236 (42%) men had any CAC There was no linear trend in the presence of CAC across LDL-C tertiles in the low (1st: 30%, 2nd: 36%, 3rd: 33%, p=0.6 for trend) and middle (1st: 46%, 2nd: 35%, 3rd: 52%, p=0.3 for trend) SBP tertile groups, respectively. On the other hand, there was a significant trend for increasing CAC with increasing LDL-C (1st: 44%, 2nd: 49%, 3rd: 83%, p<0.0001 for trend) in the high SBP tertile group. In mutlivariate logistic analyses (adjusting for age, smoking, triglyceride, waist circumference, and glucose), the odds ratio for any CAC associated with increasing LDL was significantly higher in those with highest SBP levels, whereas no such relationship was observed among men with SBP in the lower 2 tertiles (table⇓). The odds ratio for presence of CAC with LDL>140 mg/dl vs. <115 mg/dl among men with SBP>130 mm of Hg was 5.03 (95% CI: 1.54 –16.47). The interaction term (LDL x SBP) incorporated in multivariate analyses was statistically significant (p=0.016).
Conclusion: This study highlights the need for aggressive treatment of elevated LDL among individuals with high blood pressure as the risk for coronary atherosclerosis is beyond simple addition of each risk factor acting alone.