Coronary heart disease risk assessment and characterization of coronary artery disease using coronary CT angiography: comparison of asymptomatic and symptomatic groups

AIM

To evaluate the prevalence of coronary artery disease (CAD) in relation to risk of coronary heart disease (CHD) and assess plaque characteristics from coronary computed tomography (CT) angiography in asymptomatic and symptomatic patients.

MATERIALS AND METHODS

Three hundred and ninety consecutive patients [asymptomatic group, n=138; symptomatic group (atypical or non-anginal chest pain), n=252] were retrospectively enrolled. They were subsequently classified into three CHD risk categories, based on the National Cholesterol Education Program guidelines, and 10 year risks of coronary events were calculated using Framingham risk score. CT was evaluated for stenosis, plaque composition, and coronary calcium scores.

RESULTS

CAD was observed in 42% of the asymptomatic group and 62% of the symptomatic group. In the former, the prevalence of CAD in low-, moderate- and high-risk subgroups was 21.4, 47.4 and 65%, respectively, and was 33.3, 74.4, and 72.4% in the symptomatic group. Framingham 10-year risks of coronary events were significantly higher in patients with CAD than in normal participants, and receiver operating characteristics curves showed that discriminatory power was poor in the asymptomatic group and symptomatic men, and good in symptomatic women. Of the participants in the asymptomatic group, 12% exhibited only non-calcified plaques and of the symptomatic group, 7% exhibited only non-calcified plaques. The coronary calcium score was significantly higher for significant stenosis than for non-significant stenosis in both groups.

CONCLUSIONS

The prevalence of CAD was not negligible even in subgroups with low-to-moderate CHD risk. Additionally, the Framingham risk score was effective for predicting CAD only in symptomatic women. Coronary calcium scores correlated with significant stenosis; however, a sizeable percentage of both groups had only non-calcified plaques.

Transport and metabolism of the antitumour drug candidate 2'-benzoyloxycinnamaldehyde in Caco-2 cells

The transport and metabolism of the antitumour drug candidate 2'-benzoyloxycinnamaldehyde (BCA) was characterized in Caco-2 cells. BCA disappeared rapidly from the donor side without being transported to the receiver side during its absorptive transport across Caco-2 cells. Its metabolites 2'-hydroxycinnamaldehyde (HCA) and o-coumaric acid (OCA) were formed in both the donor and the receiver sides. HCA, in a separate study, also disappeared rapidly from the donor side, mostly being converted to its oxidative metabolite OCA during its absorptive transport across Caco-2 cells. OCA was transported rapidly in the absorptive direction across Caco-2 cells with a P(app) of 25.4 +/- 1.0 x 10(-6) cm s(-1) (mean +/- standard deviation (SD), n = 3). OCA was fully recovered from both the donor and the receiver side throughout the time-course of this study. Formation of HCA from BCA was inhibited almost completely by bis(p-nitrophenyl)phosphate (BNPP), a selective inhibitor of carboxylesterases (CES), and phenylmethylsulfonyl fluoride (PMSF), a broad specificity inhibitor of esterases in Caco-2 cells, suggesting that this hydrolytic biotransformation was likely mediated predominantly by CES. Conversion of HCA to OCA was inhibited significantly by isovanillin, a selective inhibitor of aldehyde oxidase (AO). Inhibitors for xanthine oxidase (XO) and aldehyde dehydrogenase (ALDH), which are known to be involved in the oxidation of aldehydes to carboxylic acids, did not have a significant effect on the biotransformation of HCA to OCA in Caco-2 cells. In summary, the present work demonstrates that BCA is hydrolysed rapidly to HCA, followed by subsequent oxidation to OCA, in Caco-2 cells. The results provide a mechanistic understanding of the poor absorption and low bioavailability of BCA after oral administration.

Predictive role of 18F-FDG-PET/CT 1 month before and after hypofractionated stereotactic body radiation therapy for stage I non-small cell lung cancer

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Background: To know the predictive role of 18F-FDG-PET/CT 1month before and after stereotactic body radiation therapy (SBRT) to stage I non-small cell lung cancer (NSCLC). Methods: Between 2004 and 2007, 20 patients received SBRT with 48 Gy for 4 consecutive days and checked two times of FDG- PET/CT and chest CT with contrast-enhancement at 1 month before and after SBRT. Change of maximal SUV (SUVmax) on FDG-PET/CT and the longest tumor diameter on chest CT before and after SBRT was measured. Patients only with high FDG uptake, SUVmax 3.0 or above, on FDG-PET/CT before SBRT and tumor diameter below 5 cm were analyzed in this study. Change of tumor diameter was classified to PR (partial response), SD (stable disease), and DP (disease progression) as RECIST criteria and change of SUVmax was described as % change. Chest CT was checked at every 3 or 6 months during follow-up. Results: Mean time intervals from SBRT to FDG-PET/CT and chest CT were 32 and 30 days respectively. Mean longest tumor diameter was changed from 2.59 cm (1.36–3.93) to 2.17 cm (1.18–3.41), and its reduction rate was -16.2%. By RECIST criteria, 4 patients showed PR, 15 patients showed SD, and other 1 patient showed DP. Mean decrease rate of SUVmax on FDG-PET/CT was -52.1% and its mean value was changed from 7.1 (3.2–13.1) to 3.4 (0.3–9.8). Median follow-up time was 16 months. Local tumor progression developed in 2 (10%) patients and time to progression was 3.4, 6.1 months. Tumor responses on post-SBRT chest CT were PR in 1 and SD in the other 1 patient, and SUVmax changes were -31.9%, -25.5% in each. Most of patients showing no response, SD or DP, didn't recur after SBRT, and so chest CT at 1 month could not predict actuarial tumor response. On the contrary to chest CT, no patients showing SUVmax decreases over 40% experienced tumor progression after SBRT. High decrease rate of SUVmax over 40% decrease on FDG-PET/CT 1 month after SBRT could warrant good actuarial local tumor control earlier. Conclusions: Change of SUVmax on FDG-PET/CT 1 month before and after SBRT could predict actuarial local tumor control of stage I NSCLC earlier and 1 month after SBRT was adequate timing for the earlier evaluation of tumor response.

No significant financial relationships to disclose.