Impact of Body Mass Index and Metabolic Syndrome on the Characteristics of Coronary Plaques Using Computed Tomography Angiography

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1 Impact of Body Mass Index and Metabolic Syndrome on the Characteristics of Coronary Plaques Using Computed Tomography Angiography Cardiovascular Division, Faculty of Medicine, University of Tsukuba Akira Sato, Tomoya Hoshi, Seiga Sai, Yuki Kakefuda, Toru Adachi, Daigo Hiraya, Taizo Kimura, Zeng Wang, Kazutaka Aonuma

2 Presenter Disclosure Information Akira Sato, MD Impact of Body Mass Index and Metabolic Syndrome on the Characteristics of Coronary Plaques Using Computed Tomography Angiography DISCLOSURE INFORMATION: Nothing to disclose related to this presentation.

3 Background The presence of metabolic syndrome (MetS) is a strong predictor of future cardiovascular disease and death. (Lakka HM, et al. JAMA. 2002;288: ) (Koren-Morag N, et al. Stroke. 2005;36: ) However, obese individuals without the MetS, sometimes referred to as metabolically healthy obese (MHO), did not demonstrate an increased risk of cardiovascular disease. (Meigs JB, et al. J Clin Endocriol Metab. 2006;91: )

4 Background Contrast-enhanced computed tomography angiography has been proposed as an emerging tool for stenosis detection, characterization, and quantification of coronary atherosclerotic plaques. (Miller JM, et al. N Engl J Med 2008;359: ) CT characteristics of culprit lesions in acute coronary syndrome (ACS) include positive remodeling (PR), lowattenuation plaques (LAP), and spotty calcification. (Motoyama S, et al. J Am Coll Cardiol 2007;50:319 26) Patients with 2 plaque characteristics (PR and LAP) on CT angiography were at a higher risk of developing ACS than patients without these characteristics during followup. (S. Motoyama et al. J Am Coll Cardiol 2009;54:49 57)

5 Purpose We hypothesized that MetS is a risk factor for cardiovascular disease and death regardless of BMI status and that overweight/obesity without MetS is not associated with higher cardiovascular risk. The purpose of this study was to investigate the association between combinations of BMI categories and MetS and the characteristics of coronary plaques using computed tomography angiography (CTA).

6 Subjects 455 patients with suspected coronary artery disease (CAD) underwent 64-slice MDCT between April 2009 and August Normal weight (BMI <25) Overweight (25 BMI<30) 1 MetS (-) n=261 3 MetS (-) n=52 2 MetS (+) n=58 4 MetS (+) n=58 Obese (30 BMI) 5 MetS (-) n=18 6 MetS (+) n=24

7 Metabolic Syndrome Criteria The Japanese criteria require central obesity as a mandatory component. Waist circumference >85 cm in men and >90 cm in women. In addition, 2 or more of the following 3 factors are necessary: 1 Systolic blood pressure of >130 mmhg and/or diastolic blood pressure of >85 mmhg 2 Serum triglyceride level >150 mg/dl and/or serum high-density lipoprotein cholesterol level <40 mg/dl 3 Fasting glucose level >110 mg/dl

8 64-slice MDCT ~Brilliance CT 64~ CT system and devices CT system: Brilliance 64 (Philips) 3D Workstation: Brilliance Workspace (Philips) Scan protocols Contrast material injection protocols Tube voltage 120 kv Concentration 370 mgi/ml Volume 60 ml (contrast) Tube current ma 40 ml (saline) Rotation time 0.42 s Flow rate 4 ml/s Slice collimation Scan start method Bolus-tracking mm HR >70/min Metoprolol 20 mg p.o.

9 Methods Coronary plaque was visually classified as follows: 1) Calcified plaque (CP) Any structure with CT attenuation of >130 HU that could be visualized separately from the contrastenhanced coronary lumen. 2) Non-calcified plaque (NCP) Calcified tissue (-) 3) Mixed plaque (MP) Plaque with non-calcified and calcified elements present (Kitagawa T, et al. Am Heart J 2007;154: ) (Kajinami K et al. J Am Coll Cardiol 1997;29: )

10 Methods Positive remodeling (PR) Target lesion of EEM-CSA/reference EEM-CSA (the average of proximal and distal) Remodeling index (RI) >1.10 Positive remodeling (Motoyama S, et al. J Am Coll Cardiol 2007;50:319-26) Low-attenuation plaque (LAP) CT density value of <50 HU (Leber AW, et al. J Am Coll Cardiol 2004;43:1241-7) Vulnerable plaque was defined as PR (RI >1.10) and LAP (CT density value <50HU) on CT.

11 MDCT (52-year-old man, LCx) Proximal MLA Distal 16 HU Remodeling index 1.28 CT value 16 HU

12 Clinical Characteristics Normal W/O MetS (n=261) Normal With MetS (n=58) Overweight W/O MetS (n=52) Overweight With MetS (n=58) Obese W/O MetS (n=18) Obese With MetS (n=24) P value Age, years 65.5± ± ± ± ± ± Male (%) 163 (62%) 51 (88%) 26 (50%) 44 (76%) 6 (33%) 14 (58%) <0.001 BMI (kg/m²) 21.4± ± ± ± ± ±2.3 <0.01 Waist (cm) 78.7± ± ± ± ± ±8.9 <0.001 Visceral fat (cm²) 85.5± ± ± ± ± ±53.1 <0.001 Hypertension (%) 134 (51%) 49 (85%) 28 (55%) 48 (83%) 8 (44%) 21 (88%) <0.001 Diabetes (%) 87 (33%) 38 (66%) 17 (33%) 40 (69%) 2 (11%) 15 (63%) <0.001 Dyslipidemia (%) 131 (51%) 35 (60%) 29 (56%) 42 (72%) 9 (50%) 19 (79%) Smoker (%) 133 (51%) 41 (71%) 22 (42%) 35 (60%) 5 (28%) 16 (67%) Hs-CRP (mg/dl) 0.18± ± ± ± ± ±

13 Characteristics of the Coronary Plaque Detected by 64-slice CT Angiography Normal W/O MetS (n=261) Normal with MetS (n=58) Overweight W/O MetS (n=52) Overweight with MetS (n=58) Obese Obese W/O MetS With MetS (n=18) (n=24) P value Calcium score 288± ± ± ±726 84± ± MVD (%) 100 (40%) 32 (55%) 13 (27%) 25 (46%) 5 (28%) 10 (42%) No. of coronary plaques per patient 2.71± ± ± ± ± ±2.40 <0.001 >50% stenosis 1.78± ± ± ± ± ±2.20 <0.001 >50% stenosis with calcified plaque >50% stenosis with non-calcified >50% stenosis with mixed plaque 0.46± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ± ±1.23 <0.001

14 Mean number of plaques (n) Mean Number of Vulnerable Plaques P <0.001 P = * P <0.01 vs normal + MetS (-) * * * MetS (-) MetS (+) (n=261) (n =58) (n=52) (n =58) (n=18) (n 24) Normal <25 Overweight Body mass index (kg/m 2 ) Obese >30

15 Logistic Regression Analysis for Detection of Vulnerable Plaque BMI/MetS categories Odds ratio (95% CI) P value Normal weight Without MetS Normal weight With MetS Overweight Without MetS Overweight With MetS Obese Without MetS Obese With MetS (reference) 5.53 ( ) < ( ) ( ) < ( ) ( ) <0.001 Data are adjusted for age, smoking, and LDL-cholesterol.

16 Summary The number of vulnerable plaques per patient was significantly higher in patients with MetS and obese patients without MetS than in normal-weight patients without MetS, whereas there was no difference in these number between overweight and normal-weight patients without MetS. In multivariate logistic analysis, an association with vulnerable plaques was observed in normal-weight patients with MetS (OR 5.53), overweight patients with MetS (OR 6.31), obese patients without MetS (OR 3.43), and obese patients with MetS (OR 6.66) but not observed in overweight patients without MetS, compared with normal-weight patients without MetS.

17 Study Limitations The sample size was relatively small. We excluded patients with severely calcified lesions and motion artifact in this study. CT plaque density can be altered by the concentration of the contrast agent administered, by contrast type, or by the model of CT used.

18 Conclusion MetS and obese patients without MetS are associated with coronary vulnerable plaques, whereas overweight patients without MetS had no significant increased risk of plaque vulnerability. 64-slice MDCT allows noninvasive assessment of vulnerable plaques throughout the coronary arteries, which is necessary for optimal medical therapy to prevent cardiovascular events.