Impact of Obesity on the Risk of Aortic Dilatation in Patients with Bicuspid Aortic Valve

Transcription

1 Impact of Obesity on the Risk of Aortic Dilatation in Patients with Bicuspid Aortic Valve Marianna Buonocore, Ciro Bancone, Sabrina Manduca, Franco E. Covino, Marco V. Montibello, Giovanni Dialetto, Alessandro Della Corte Cardiac Surgery Unit and Echocardiography Service Department of Cardiothoracic Sciences Second University of Naples - V.Monaldi Hospital Naples, Italy

2 Introduction Why obesity? Clinical worldwide impact of a preventable risk factor Common pathways implied in obesityassociated aortopathy and bicuspid- related aortopathy (enos, TGF-β) Usefulness of elucidate the possible role of interrelated factors influencing BAV aortopathy

3 Methods All trans-thoracic and trans-esophageal examinations performed at our Institution s Echocardiography Unit between January 1998 and April 2014 were retrospectively reviewed and those evidencing a congenital BAV in an adult subject were considered for this study Anthropometric, echocardiographic and clinical information of 715 adult BAV patients were entered in a local database

4 The relation between obesity and aortic diameters (root and ascending), and the presence of aortic aneurysm was assessed, stratifying with respect to other well known factor affecting the aortic phenotype (i.e. gender, age, hypertension, valve function, cusp fusion pattern)

5 Definitions Expected normal aortic diameters: Roman s regression formula (BSA and age); Aortic ratio (AR): measured/expected diameter; Aortic dilatation: AR >1.15, (average diameter 3.9 cm) Severe aortic dilation (=aneurysm): AR 1.5 (average diameter 5 cm); Definition and classification of Obesity: BMI (kg/m 2 ) Classification < underweight normal weight overweight class I obesity class II obesity class III obesity BMI= m h 2

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7 Predictors of Aortic Diameters Cohort of BAVs with Normal aortic diameters and Normal valve function LINEAR REGRESSION AND CORRELATIONS ROOT Diameter: BSA(0,48)=WEIGHT(0.48)>BMI(0,39)>HEIGHT(0,35)>AGE(0,34) ASCENDING Diameter: BSA(0.48)>AGE(0.34)>WEIGHT(0.32)>HEIGHT(0.28) MULTIVARIABLE REGRESSION e PREDICTORS ROOT Diameter is predicted by GENDER (M) and AGE ASCENDING Diametr is predicted by AGE and BSA

8 Predictors of Aortic Diameters In the whole BAV population LINEAR REGRESSION e CORRELATIONS ROOT Diameter: BSA(0.28)>WEIGHT(0.27)>HEIGHT(0.24)>AGE(0.17)=BMI ASCENDING Diameter: AGE(0.36)>BMI(0.25)>WEIGHT(0.16) MULTIVARIABLE REGRESSION e PREDICTORS ROOT Diameter is predicted by GENDER(M), AGE, BSA ASCENDING Diameter is predicted by AGE, BMI

9 Considerations: In the cohort of «normal» BAVs, BMI didn t show significant correlation with aortic diameters, which were predicted by AGE and BSA (ascending) and by AGE and GENDER (root). In the whole BAV population, BMI had instead a significant correlation with diameters, but only at the Ascending tract May Be the Correlation between Ascending diameter and Obesity Affected by the Age confounding Factor? Also BMI and AGE showed a correlation (R=0.26). Since both emerge as predictive factors in the multivariable model: BMI is an indipendent predictor of the ascending aortic diameter in BAV population.

10 Prevalence of obesity in our BAV population: 19.6% Stratified for decades of age: p< YRS 1.8% YRS 14.7% YRS 25.2% YRS 23.8% YRS 24.9%

11 Obesity Sig.(p) HYPERTENSION NORMOTENSION AORTIC STENOSIS NO AORTIC STENOSIS AORTIC REGURGITATION NO AORTIC REGURGITATION COPD NO COPD 28.8% 17.4% 22.9% 17.1% 15.6% 21.7% 30.5% 18.6% p=0.003 p=0.05 p=0.05 p=0.02 STRATIFYING FOR DECADES OF AGE

12 Which is the impact of obesity on the aortopathy associated with BAV?

13 Prevalence of obesity in BAV patients with and without Aortopathy 23.7% Dilat. Root vs 17.0% No-Dilat. Root (p=0.03) 23.5% Dilat. Asc vs 11.5% No-Dilat.Asc (p<0.001) 36.2% Aneurysm vs 18.5% No-Aneurysm (p=0.005) Obesity shows significant correlation with root and ascending dilatation, and with the presence of aneurysm.

14 T-test BMI 30 BMI<30 P Age <0.001 Root Diameter n.s. Ascending Diameter <0.001 Max Diameter <0.001 Obese BAVs have a mean diameter at the Ascending tract significantly greater (3 mm) than non-obese. BIASED BY AGE? NO. Comparing two cohorts with corresponding age (BAV population yrs old, mean age 47.1 yrs), we still found a significant difference in mean ascending diameter between obese and non-obese patients (4.4mm vs 4.2mm, p=0.02)

15 Not-Obese Ascending Diameter Obese Age

16 Predictors of Aortic Diameters In the whole BAV population, including BMI 30 (Obesity) MULTIVARIABLE REGRESSION & PREDICTORS Dependent Variable: ASCENDING Diameter Predictors in the Model: Obesity p=0.004 Age Hypertension Female Gender No significant Ao. Stenosis Fusion Pattern R-N

17 OBESITY & AORTIC ANEURYSM

18 Significant association between OBESITY and aortic ANEURYSM in the general cohort (p=0.006), and in the subgroups: RN fusion pattern Nomal Blood Pressure Normal Valve Function AORTIC ANEURYSM Obese Not-Obese Sig.(p) Pattern RL 10.3% 6.1% n.s. Pattern RN 20.7% 4.1% Hypertension 13.8% 9.1% n.s. No Hypertension 15.2% 4.3% <0.001 Altered Valve function 8.3% 5.1% n.s. Normal Valve function 24.4% 7.0% <0.001

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20 Predictors of Aortic Aneurysm In the whole BAV population, including BMI 30 (Obesity) MULTIVARIABLE REGRESSION & PREDICTORS Dependent Variable: Aortic ANEURYSM Predictors in the Model: Obesity p=0.03 Age COPD No significant Ao. Stenosis

21 Limitations of the study No control group (TAV) Patient Referral

22 Conclusions There is a significant impact of BMI on the presence and severity of aortopathy in BAV patients. The obesity factor is likely to have complex interactions with other known modifiers of the aortic phenotype. This study suggests which BAV patient profiles (RN fusion, ascending phenotype, aged) could benefit more from dietary and medical interventions aiming at preventing or controlling BMI increase.