Evaluating the effects of insulin resistance and hypertension in obese children on cardiac functions using echocardiography

Abstract

Objective: The purpose of this research was aimed to evaluate the cardiac functions of obese children by echocardiography and in addition to find out the affects of insulin resistance and/or hypertension on cardiac functions. 

Material and Method: The Obese group included 52 children in this study (32 boys and 20 girls) with ages ranged between 4-19 years old (mean 11.6±3.7 years) and BMI ≥ 95 percentiles. Children with appropriate for age (4-19 years, mean 11.0±4.1 years), sex (25 boys and 19 girls), and with normal BMI were selected as control group. Serum fasting glucose, thyroid functions, lipid profile, insulin and cortisole levels were measured in the obese group. The patients were also divided into 4 subgroups according to existing of hypertension and/or insulin resistance, and they were also compared between each other. Echocardiographic measurements of both groups were made by using M-mode, 2-D and PW Doppler techniques and MPI values of the left and the right ventricles were calculated. The student’s t test was used to compare the main groups, and analysis of variance (One Way ANNOVA) was used to compare the obese subgroups between each other and with the controls. Post hoc testing was also applied by using the Sidak multiple comparisons test. Probability values of p <0.05 in all tests were considered significant.

Results: The mean BMI value of obese children was 29.37±5.08 kg/m2 whereas mean BMI of controls was 26.66±7.84 kg/m2 (p<0.05). The mean SBP (115.9±13.2 mmHg) and also the mean DBP (70.6±10.1 mmHg) values of the obese group were significantly higher from the control group values (respectively 110.8±8.8 and 65.7±7.8 mmHg). LVDd, IVSd, LVM, LVM/height^2.7, SV, IVRT, EF and FS values of the obese group were significantly higher than the values of control group. It was revealed that these parameters were higher in the subgroup with IR alone and the subgroup with HT&IR, when compared to the control group. There was no significant difference between the values of E, A, and E/A of the control and the obese groups On the other hand, both IVRT and MPI values of right and left ventricle were significantly higher in children with obesity than controls. No differences of MPI values of the left ventricle were noted between obese subgroups. Finally, it was found out that the significant difference between obese and control groups for the MPI values of right ventricle was originated from obese subgroups with IR alone and with HT&IR.

Conclusion: HT and/or IR accompanying to obesity could worsen the present cardiac dysfunction. We suggest that the measurement of MPI and IVRT values in children with obesity, as it used in many other diseases, can reveal the cardiac dysfunction at the early stages, and should be considered as a useful and valuable parameters.

Keywords

• Child, Echocardiography; Hypertension; Insulin resistance; Myocardial Performance Index; Obesity

Obez Çocuklardaki Hipertansiyon ve İnsülin Direncinin Kardiyak İşlev Bozukluğuna Etkisinin Ekokardiyografi İle Değerlendirilmesi

Öz

Amaç: Bu çalışmada obez çocukların kardiyak işlevlerinin ekokardiyografi ile değerlendirilmesi, ayrıca bulunan sonuçlara insülin direnci ve hipertansiyonun ne şekilde etki ettiğinin araştırılması amaçlanmıştır.

Gereç ve Yöntem: Yaşları 4–19 arasında değişen (ortalama 11,6±3,70 yıl) ve VKİ 95 persantil ve üzerindeki 52 çocuk (Erkek:32, Kız:20) çalışmaya dahil edildi. VKİ normal sınırlarda olan, yaş (4-19, ortalama 11,0±4,1 yıl) ve cinsiyeti (Erkek:25, Kız:19) uyumlu 44 sağlıklı çocuk kontrol grubunu oluşturdu. Obezlerde açlık kan şekeri, tiroit hormonları, lipit profili, insülin ve kortizol düzeyleri ölçüldü. Obez hastalar ayrıca hipertansiyon ve/veya insülin direnci olup olmamasına göre 4 alt gruba da ayrılarak kıyaslandı. Hasta ve kontrol grubunun hem sağ hem de sol ventrikülün M mod, iki boyutlu ve Doppler ekokardiyografi ölçümleri yapıldı. Sağ ve sol ventrikülün MPİ değerleri hesaplandı. Grupların karşılaştırılmasında bağımsız örneklem t-testi, Tek Yönlü Varyans Analizi Testi (One-Way ANOVA) kullanıldı, Post Hoc testinde Sidak yöntemi kullanıldı, p<0.05 anlamlı olarak kabul edildi.

Bulgular: Obez çocukların VKİ ortalaması 29,37±5,08 kg/m2 kontrol grubunun VKİ ortalaması ise 26,66±7,84 kg/m2 bulundu (p<0.05). Obez çocukların hem SKB ortalaması (115,9±13,2 mmHg) hem de DKB ortalaması (70,6±10,1 mmHg) kontrol grubunun ortalamalarından (sırasıyla 110,8±8,8 ve 65,7±7,8 mmHg) anlamlı olarak yüksek idi. Obez grubun SVDSÇ, IVSd, SVK, SVK/boy^2.7, SV, IVGZ, EF ve KF değerleri kontrol grubunkinden anlamlı olarak yüksek bulundu. Kontrol grubu ile alt gruplar kıyaslandığında bu istatistiksel farklılığın tek başına İR ve hem İR hem de HT’nun birlikte olduğu obez alt gruplarda daha belirgin olduğu saptandı. Kontrol grubuyla obez çocuk grubunun hem sağ ventrikül ve hem de sol ventrikülün erken ve geç dolum hızları, E/A oranları arasında istatiksel anlamlı farklılık saptanmadı. Buna karşın hem sol ventrikülün hem de sağ ventrikülün İVGZ ve MPİ değerleri obezlerde kontrole göre anlamlı olarak artmıştı. Sol ventrikülün MPİ değeri obez alt grupları arasında farklılık göstermez iken, sağ ventrikül MPİ değerinin kontrollere göre asıl anlamlı farklılığının ise tek başına İR olan ve hem İR hem de HT olan iki obez alt gruptan kaynaklandığını saptadık.

Sonuç: Obezite ile İR ve/veya HT birlikteliği kardiyak işlev bozukluğunu belirginleştirebilir. MPİ ve İVGZ değerlerinin, diğer birçok hastalıklarda olduğu gibi obezitede de ve henüz hastalığın asemptomatik evresinde kalp işlev bozukluğunu göstermede kullanışlı ve değerli parametreler olduğu kanısındayız.

Anahtar Kelimeler

• Çocuk; Ekokardiyografi; Hipertansiyon; İnsülin Direnci; Miyokardiyal Performans İndeksi; Obezite

Kaynakça

1. Günöz H. Şişmanlık. Neyzi O, Ertuğrul T, (edt), Pediatri. Nobel 2002; 22: 1-226.
2. Harada K, Orino T, Takada G. Body Mass Index Can Predict Left Ventricular diastolic filling in asymptomatic obese children. Pediatric Cardiol 2001; 22: 273-278.
3. Tütüncüler F, Firdevs B: Çocuk ve adolesan yaşlarda insülin direnci ve klinik yansımaları. 27. Pediatri günleri özet kitabı: 2005 nisan 41-45: İstanbul.
4. Alpert MA. Obesity Cardiomyopathy: Pathophysiology and Evolution of the Clinical Syndrome. Am J Med Sci 2001; 321(4): 225-236.
5. Tei C: New non-invasive index for combined systolic and diastolic ventricular function. J Cardiol 1995; 26: 396–404.
6. Tei C, Nishimura RA, Seward JB, Tajik AJ: Non-invasive doppler-derived myocardial performance index: correlation with simultaneous measurements of cardiac catheterization measurements. J Am Soc Echocardiogr 1997; 10: 169-78.
7. Tei C, Dujardin KS, Hodge DO, Kyle RA, Tajik AJ, Seward BJ. Doppler index combining systolic and diastolic myocardial performance: clinical value in cardiac amyloidosis. J Am Coll Cardiol 1996; 28: 658–64.
8. Ertürk L, Gökşen D, Özyürek A R, Darcan Ş, Çoker M. Usefullness of the myocardial performance index (MPI) for assessing ventricular function in obese pediatric patients. The Turki J Pediatr 2005; 47: 34-38.

9. T Tekten, A Onbaşılı, C Ceyhan, S Ünal, B Dişçigil. Value of Measuring Myocardial Performance Index by Tissue Doppler Echocardiography in Normal and Diseased Heart. Jpn Heart J May 2003.
10. Nishimure E, Abel MD, Hattle LK, Tajik AJ. Assessment of diastolic function of the heart: background and current applications of Doppler echocardiography. Part I, Physiologic and pathophysiology features, May Clin Proc 1989; 64:71-81.
11. Daniel JP. The basis of ventricular function. Cardiol Yuung 1999; 9:210-223.
12. Harizi RC, Bianco JA, Alpert JS. Diastolic function of the heart in clinical cardiology. Arch Intern Med 1988;148: 99-109.
13. Olcay Neyzi, Hülya Günöz, Andrzej Furman, Rüveyde Bundak, Gülbin Gökçay, Feyza Darendeliler, Firdevs Baş. Türk çocuklarında vücut ağırlığı, boy uzunluğu, baş çevresi ve vücut kitle indeksi referans değerleri. Çocuk Sağlığı ve Hastalıkları Dergisi 2008; 51: 1-14.
14. Tümer N, Yalçınkaya F, İnce E, Ekim M, Köse K, Çakar N, Kara N, Özkaya N, Ensari C, Önder S. Pediatr Nephrol Jun 1999;13(5):438-43.
15. Ersoy B, Ulman C. Obez ve obez olmayan çocuklarda aterosklerotik belirleyiciler ve bunların vücut kompozisyonu ile ilişkisi. Ege Pediatri Bülteni 2004; 11: 83-89.
16. Tourian P, Aggoun Y, Dubern B. Presence of increased stiffness of the common carotid artery and endothelial dysfunction in severely obese ehiidren: a prospective study. Lancet 2001; 358: 1400-1404.
17. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (ACC/AHA/ASE Committee to Update the 1997 Guidelines for the Clinical Application of Echocardiography). J Am Coll Cardiol. 2003 Sep 3;42 (5):954-70
18. Merlino G, Scaglione R, Corrao S, et al. Association between reduced lymphocyte beta-adrenergic receptors and left ventricular dysfunction in young obese subjects. Int J Obes Relat Metab Disord 1994;18: 699-703.
19. Messerli FH, Sungaard-Riise ED, Dreslinski GR, et al. Dimorphic cardiac adaptation to obesity and arterial hypertension. Ann Intern Med 1983; 94: 757–61.
20. Lavie CJ, Amodeo C, Ventura HO, et al. Left atrial abnormalities indicating diastolic ventricular dysfunction in cardiomyopathy of obesity. Chest 1987; 92:1042–6.
21. Nakajima T, Fuhoka S, Tokunaga K, et al. Noninvasive study of left ventricular performance in obese patients: Influences of duration of obesity. Circulation 1985; 71:481-6.
22. Ku C, Lin S, Wang D, et al. Left ventricular filling in normotensive obese adults. Am J Cardiol 1994;73: 613–5.
23. Karason K, Wallentin I, Larsson B, et al. Effects of obesity and weight loss on left ventricular mass and relative wall thickness: Survey and intervention study. BMJ 1997;315: 912–8.
24. Alpert MA, Terry BE, Kelly DL. Effect of weight loss on cardiac chamber size, wall thickness and left ventricular function in morbid obesity. Am J Card 1985; 55: 783-786.
25. Sasson Z, Rasooly Y, Bhesania T, Rasooly I. Insulin resistance is an important determinant of left ventricular mass in the obese. Circulation. 1993;88:1431-6.
26. Scaglione R, Dichiara MA, Indovina R, et al. Left ventricular diastolic and systolic function in normotensive obese subjects. Influence of degree and duration of obesity. Eur Heart J 1992;13:138–42.
27. Merlino G, Scaglione R, Paterna S, et al. Lymphocyte beta-adrenergic receptors in young subjects with peripheral or central obesity. Relationship with central hemodynamic and left ventricular function. Eur Heart J 1994;15: 786–92.
28. Karason K, Wallentin I, Larsson B, et al. Effects of obesity and weight loss on cardiac function and valvular performance. Obes Res 1998; 6: 422–9.
29. Stoddard MF, Tseuda K, Thomas M, et al. The influence of obesity on left ventricular filling and systolic function. Am Heart J 1992;124: 694–9.
30. Koehler B, Maleck-Tendera E, Drzewicka B, et al. Evaluation of the cardiovascular system in children with simple obesity: echocardiographic assessment. Makena Med Polona 1989;2:131–3.
31. Alexander JK, Dennis EW, Smith WG, et al. Blood volume, cardiac output and distribution of systemic blood flow in extreme obesity. Cardiovasc Res Center Bull 1962;1: 39–44.
32. Powell BD, Redfield MM, Bybee KA, Freeman WK, Rihal CS. Association of Obesity With Left Ventricular Remodeling and Diastolic Dysfunction in Patients Without Coronary Artery Disease. Cardiol 2006; 98: 116 –120.
33. Chakko S, Mayer M, Allison MD, et al. Abnormal left ventricular diastolic filling in eccentric left ventricular hypertrophy of obesity. Am J Cardiol 1991; 68: 95–8.
34. Alpert MA, Singh A, Terry BE, et al. Effect of exercise and cavity size on right ventricular function in morbid obesity. Am J Cardiol 64: 1361–5.
35. Wikstrand J, Pettersson P, Bjorntorp P. Body fat distribution and left ventricular morphology and function in obese females. J Hypertens 1993;11: 1259–66.
36. Gaibazzi N, Petrucci N, Ziacchi V. Left ventricle myocardial performance index derived either by conventional method or mitral annulus tissue-Doppler: a comparison study in healthy subjects and subjects with heart failure. J Am Soc Echocardiogr 2005;18:1270-6.
37. Andersen NH, Poulsen SH, Helleberg K, Ivarsen P, Knudsen ST, Mogensen CE. Impact of essential hypertension and diabetes mellitus on left ventricular systolic and diastolic performance. Eur J Echocardiogr 2003; 4: 306-12.