Review
Obesity and Coronary Artery Disease: Evaluation and Treatment

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Abstract

With the increasing prevalence of obesity, clinicians are now facing a growing population of patients with specific features of clinical presentation, diagnostic challenges, and interventional, medical, and surgical management. After briefly discussing the effect of obesity on atherosclerotic burden in this review, we will focus on strategies clinicians might use to ensure better outcomes when performing revascularization in obese and severely obese patients. These patients tend to present comorbidities at a younger age, and their anthropometric features might limit the use of traditional cardiovascular risk stratification approaches for ischemic disease. Alternative techniques have emerged, especially in nuclear medicine. Positron emission tomography-computed tomography might be the diagnostic imaging technique of choice. When revascularization is considered, features associated with obesity must be considered to guide therapeutic strategies. In percutaneous coronary intervention, a radial approach should be favoured, and adequate antiplatelet therapy with new and more potent agents should be initiated. Weight-based anticoagulation should be contemplated if needed, with the use of drug-eluting stents. An “off-pump” approach for coronary artery bypass grafting might be preferable to the use of cardiopulmonary bypass. For patients who undergo bilateral internal thoracic artery grafting, harvesting using skeletonization might prevent deep sternal wound infections. In contrast to percutaneous coronary intervention, lower surgical bleeding has been observed when lean body mass is used for perioperative heparin dose determination.

Résumé

Avec l'augmentation de la prévalence de l'obésité, les cliniciens font face à une population croissante de patients présentant des caractéristiques spécifiques en termes de présentation clinique, de défis diagnostiques et thérapeutiques, en ce qui a trait à la prise en charge médicale et aux techniques de revascularisation. Après avoir brièvement discuté des répercussions de l'obésité sur l'athérosclérose, cet article mettra l'accent sur les stratégies que peuvent utiliser les cliniciens pour l’obtention de résultats optimaux concernant les questions de revascularisation chez les patients obèses et sévèrement obèses. Ces patients ont tendance à présenter des comorbidités à un plus jeune âge, et leurs caractéristiques anthropométriques peuvent limiter l'utilisation des approches de la stratification traditionnelle à la recherche d’ischémie myocardique. Des techniques alternatives ont vu le jour en particulier en médecine nucléaire. La tomographie par émission de positron (TEP rubidium) peut s’avérer la technique d'imagerie diagnostique de choix. Une fois la revascularisation considérée, les caractéristiques associées à l'obésité doivent moduler les stratégies thérapeutiques. Lors d’une intervention coronarienne percutanée (ICP), une approche radiale doit être favorisée et les nouveaux agents antiplaquettaires devraient être privilégiés. Lors d’une ICP, une anticoagulation titrée à partir du poids total du patient de concert avec l'utilisation des endoprothèses médicamenteuses est conseillée. Au sujet de la revascularisation chirurgicale, une approche de type « coeur battant » pour la revascularisation par pontage coronarien peut conférer des avantages supplémentaires par rapport à l'utilisation de la circulation extracorporelle. Pour les patients où le chirurgien utilise les deux artères mammaires internes, le prélèvement de l’artère par squelettisation a montré des avantages intéressants pour prévenir les infections de plaie sternale profonde. Un risque de saignement chirurgical plus faible a été observé quand la masse maigre du patient est utilise pour la détermination des doses périopératoires d’héparine.

Section snippets

Epidemiology

The most commonly used anthropometric tool to classify obesity is body mass index (BMI), the ratio of total body weight in kilograms divided by the height in meters squared (kg/m2). The different classes of obesity are described in Table 1. Obesity is an independent risk factor for cardiovascular (CV) disease (CVD).1, 2 It also increases the incidence of traditional CV risk factors like hypertension, dyslipidemia, and diabetes mellitus, leading to a greater incidence of ischemic stroke and

Obstructive Coronary Artery Disease and Obesity

The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study, based on postmortem examination of arteries from young individuals who died from accidental injuries, homicides, or suicides, was landmark in understanding the relationship between atherosclerosis and obesity.19 This study documented that obesity in adolescents and young adults accelerates the progression of atherosclerosis decades before the appearance of clinical manifestations, and that high BMI correlates with more

Electrocardiogram

The electrocardiogram (ECG) is modified by structural changes related to obesity. The heart is displaced by diaphragmatic elevation in the prone position. Increased circulating blood volume leads to increased stoke volume, which increases cardiac output and results in left chamber hypertrophy.22 Subcutaneous and epicardial fat influences ECG because of the increased distance between the heart and the electrodes.1 These ECG findings are well defined in the landmark study in 1029 obese patients (

Treadmill stress test

Standard stress test performance is limited in obesity patients by several factors, which often make other approaches more useful. ECG modification might limit accurate interpretation. Aerobic capacity is diminished because of pulmonary dysfunction, orthopaedic limitations, and LV diastolic dysfunction. Many obese patients fail to achieve the 80%-85% age-predicted heart rate needed for diagnostically-valid results.46, 47 Chronotropic competence is reduced, with peak heart rate, heart rate

Single photon emission computed tomography

Single photon emission computed tomography has a sensitivity of 87% and specificity of 73%.59, 60 The main pitfalls in obesity remain attenuation artifacts. Technetium sestamibi is the marker of choice in the obese because of greater energy emission, which generates better images.61 The down side is a higher rate of false positive results in severely obese patients.62 Attenuation protocols limit the rate of false positivity.63

Positron emission tomography-computed tomography

Positron emission tomography (PET)–computed tomography rubidium has a

Non-ST-elevation myocardial infarction and obesity

Obesity is the strongest factor associated with non-ST-elevation myocardial infarction (NSTEMI) at a younger age, followed by tobacco use.66 For overweight and obesity classes 1, 2, and 3, the mean age for NSTEMI was 3.5, 6.8, 9.4, and 12.0 years earlier compared with normal weight individuals, respectively.

ST-elevation myocardial infarction and obesity

A recent study using cMRI determined that ST-elevation myocardial infarction (STEMI) infarct size in patients with BMI ≥ 25 was significantly smaller vs normal weight patients67 but only 5

In-hospital Events After PCI

The CathPCI Registry examined in-hospital complications of 83,861 severely obese patients.101 After multivariable adjustment, obesity was independently associated with a greater mortality rate (OR, 1.14) and a lower bleeding rate (OR, 0.80).101 Although severe obesity affects weight-based dosing protocols for unfractionated heparin,102 this population is underrepresented or even excluded from major trials.102 It remains unclear whether one should use the maximum dose recommended or weight-based

Long-term Follow-up After PCI

Low BMI patients tend to have more events after PCI than obese patients.105, 106 A study of 23,181 patients from 11 prospective PCI studies used a BMI of 22.5-24.9 as the reference category: the risk of major CV events was increased among patients with a lower BMI (HR, 1.52 for BMI < 18.5) and declined among patients with a higher BMI (eg, 0.78 for a BMI ≥30.0).107 A recent meta-analysis of 10 post-PCI and 12 post-CABG studies confirmed these findings.108 This obesity paradox seems to wane when

Perioperative mortality

Obesity has been inconsistently associated with an increased in-hospital mortality after CABG. An analysis of the Society of Thoracic Surgeons' database (559,004 patients who underwent isolated CABG between 1997 and 2000118) showed an increased risk of in-hospital mortality in moderately obese (n = 42,060; BMI = 35-39.9; OR, 1.21) and severely obese patients (n = 18,735; BMI ≥ 40; OR, 1.58) compared with subjects with a BMI of 18.5-34.9. These results contrasted with previous studies that found

Conclusions

Patients with varying degrees of excess weight and obesity are becoming increasingly treated with PCI and CABG surgery. For PCI, miniaturization of equipment, radial approach, and weight-based anticoagulation minimize acute risks of vascular complications and bleeding and accelerate ambulation and early hospital discharge. The use of DES and stronger antiplatelet agents have also optimized mid- and long-term outcomes. For obese patients who require surgical revascularization, CABG remains an

Acknowledgements

David Garcia-Labbé and Emmeline Ruka contributed equally to this work.

References (148)

  • E. Abergel et al.

    Influence of obesity on the diagnostic value of electrocardiographic criteria for detecting left ventricular hypertrophy

    Am J Cardiol

    (1996)
  • P.N. Casale et al.

    Electrocardiographic detection of left ventricular hypertrophy: development and prospective validation of improved criteria

    J Am Coll Cardiol

    (1985)
  • B.D. Powell et al.

    Association of obesity with left ventricular remodeling and diastolic dysfunction in patients without coronary artery disease

    Am J Cardiol

    (2006)
  • O.J. Rider et al.

    Beneficial cardiovascular effects of bariatric surgical and dietary weight loss in obesity

    J Am Coll Cardiol

    (2009)
  • D.D. Savage et al.

    Prevalence and correlates of posterior extra echocardiographic spaces in a free-living population based sample (the Framingham study)

    Am J Cardiol

    (1983)
  • G. Iacobellis et al.

    Echocardiographic epicardial fat: a review of research and clinical applications

    J Am Soc Echocardiogr

    (2009)
  • E.B. Turkbey et al.

    The impact of obesity on the left ventricle: the Multi-Ethnic Study of Atherosclerosis (MESA)

    JACC Cardiovasc Imaging

    (2010)
  • L.A. Gondoni et al.

    Heart rate behavior during an exercise stress test in obese patients

    Nutr Metab Cardiovasc Dis

    (2009)
  • P.A. McCullough et al.

    Cardiorespiratory fitness and short-term complications after bariatric surgery

    Chest

    (2006)
  • E. Argulian et al.

    Predictors of ischemia in patients referred for evaluation of exertional dyspnea: a stress echocardiography study

    J Am Soc Echocardiogr

    (2013)
  • S.L. Mulvagh et al.

    Contrast echocardiography: current and future applications

    J Am Soc Echocardiogr

    (2000)
  • E.C. Madu

    Transesophageal dobutamine stress echocardiography in the evaluation of myocardial ischemia in morbidly obese subjects

    Chest

    (2000)
  • C.R. Weinberg et al.

    Effect of body mass index on outcome in patients with suspected coronary artery disease referred for stress echocardiography

    Am J Cardiol

    (2013)
  • A.S. Iskandrian et al.

    Thallium imaging with single photon emission computed tomography

    Am Heart J

    (1987)
  • R.S. Korbee et al.

    What is the value of stress (99m)Tc-tetrofosmin myocardial perfusion imaging for the assessment of very long-term outcome in obese patients?

    J Nucl Cardiol

    (2013)
  • K. Yoshinaga et al.

    What is the prognostic value of myocardial perfusion imaging using rubidium-82 positron emission tomography?

    J Am Coll Cardiol

    (2006)
  • B.J. Chow et al.

    Prognostic value of PET myocardial perfusion imaging in obese patients

    JACC Cardiovasc Imaging

    (2014)
  • M.C. Madala et al.

    Obesity and age of first non-ST-segment elevation myocardial infarction

    J Am Coll Cardiol

    (2008)
  • G.H. Sohn et al.

    Impact of overweight on myocardial infarct size in patients undergoing primary percutaneous coronary intervention: a magnetic resonance imaging study

    Atherosclerosis

    (2014)
  • S.R. Das et al.

    Impact of body weight and extreme obesity on the presentation, treatment, and in-hospital outcomes of 50,149 patients with ST-Segment elevation myocardial infarction results from the NCDR (National Cardiovascular Data Registry)

    J Am Coll Cardiol

    (2011)
  • J. Huang et al.

    Comparison of clinical features and outcomes of patients with acute myocardial infarction younger than 35 years with those older than 65 years

    Am J Med Sci

    (2013)
  • G. Anfossi et al.

    Platelet dysfunction in central obesity

    Nutr Metab Cardiovasc Dis

    (2009)
  • H.W. Cohen et al.

    Aspirin resistance associated with HbA1c and obesity in diabetic patients

    J Diabetes Complications

    (2008)
  • G. Feher et al.

    Clopidogrel resistance: role of body mass and concomitant medications

    Int J Cardiol

    (2007)
  • M. Pankert et al.

    Impact of obesity and the metabolic syndrome on response to clopidogrel or prasugrel and bleeding risk in patients treated after coronary stenting

    Am J Cardiol

    (2014)
  • N. Cox et al.

    Comparison of the risk of vascular complications associated with femoral and radial access coronary catheterization procedures in obese versus nonobese patients

    Am J Cardiol

    (2004)
  • B. Hibbert et al.

    Transradial versus transfemoral artery approach for coronary angiography and percutaneous coronary intervention in the extremely obese

    JACC Cardiovasc Interv

    (2012)
  • P. Poirier et al.

    Obesity and cardiovascular disease: pathophysiology, evaluation, and effect of weight loss: an update of the 1997 American Heart Association Scientific Statement on Obesity and Heart Disease from the Obesity Committee of the Council on Nutrition, Physical Activity, and Metabolism

    Circulation

    (2006)
  • P. Poirier et al.

    Obesity and cardiovascular disease

    Curr Atheroscler Rep

    (2002)
  • D. Wormser et al.

    Separate and combined associations of body-mass index and abdominal adiposity with cardiovascular disease: collaborative analysis of 58 prospective studies

    Lancet

    (2011)
  • K. Wilkins et al.

    Blood pressure in Canadian adults

    Health Rep

    (2010)
  • B. Plourde et al.

    Sudden cardiac death and obesity

    Expert Rev Cardiovasc Ther

    (2014)
  • H.B. Hubert et al.

    Obesity as an independent risk factor for cardiovascular disease: a 26-year follow-up of participants in the Framingham Heart Study

    Circulation

    (1983)
  • A. Engeland et al.

    Body mass index in adolescence in relation to total mortality: 32-year follow-up of 227,000 Norwegian boys and girls

    Am J Epidemiol

    (2003)
  • J.E. Manson et al.

    A prospective study of obesity and risk of coronary heart disease in women

    N Engl J Med

    (1990)
  • P.W. Wilson et al.

    Overweight and obesity as determinants of cardiovascular risk: the Framingham experience

    Arch Intern Med

    (2002)
  • K.M. Flegal et al.

    Association of all-cause mortality with overweight and obesity using standard body mass index categories: a systematic review and meta-analysis

    JAMA

    (2013)
  • E.E. Calle et al.

    Body mass index and mortality in a prospective cohort of U.S. adults

    N Engl J Med

    (1999)
  • J.P. Despres

    Body fat distribution and risk of cardiovascular disease: an update

    Circulation

    (2012)
  • J.P. Despres et al.

    Regional distribution of body fat, plasma lipoproteins, and cardiovascular disease

    Arteriosclerosis

    (1990)
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