Traumatic brain injury, coronary atherosclerosis and cardiovascular mortality.

Background: Traumatic-brain-injury (TBI) is a devastating-condition resulting in cerebral edema and ischemia. This study investigates the association of mild-TBI (mTBI) to sub-clinical atherosclerosis and cardiovascular (CV) mortality.

Methods: Five hundred and forty-three veterans without known coronary artery disease or diagnosed mental disorder, who underwent coronary artery calcium (CAC) scanning for clinical indications, were followed for a median of 4-years. Veterans' medical diagnoses and neuropsychiatric health status (mTBI vs non-mTBI) were evaluated using VA electronic medical records. CAC was defined as 0, 1-100, 101-400 and 400+.

Results: CAC was higher in mTBI, compared to without-mTBI (p < 0.05). TBI was more prevalent with the-severity of CAC (p < 0.05). Regression-analyses revealed that mTBI is an independent-predictor of CAC (p < 0.01). The CV mortality rate was 25% in mTBI and 10.5% in without-mTBI (p = 0.0001). Multivariable survival regression analyses revealed a significant-association between mTBI and CAC, with increased-risk of CV mortality (p < 0.05). The hazard-ratio of CV mortality was 5.25 in mTBI & CAC > 0, compared to without-mTBI & CAC = 0 (p < 0.05). The risk of CV-mortality was 2.25 for mTBI & CAC = 1-100, 4.93 for mTBI & CAC = 101-400 and 7.06 for mTBI & CAC ≥ 400, compared to matched CAC-categories without-mTBI (p < 0.05). The area under ROC curve to predict CV mortality was 0.64 for mTBI, 0.69 for mTBI & PTSD, 0.85 for mTBI & CAC > 0 and 0.92 for the combination. The prognostication of mTBI to predict CV mortality is superior to the Framingham risk score. Also the combination of mTBI & PTSD provided incremental prognostic values to predict CV mortality (p < 0.05).

Conclusions: mTBI is associated with the severity of sub-clinical coronary atherosclerosis and independently predicts CV mortality.