Updates on Cardiac Enlargement in US Firefighters. Maria Korre, MSc, ScD

Transcription

1 Updates on Cardiac Enlargement in US Firefighters Maria Korre, MSc, ScD Research Associate-Instructor Environmental & Occupational Medicine & Epidemiology Program Department of Environmental Health Harvard T.H. Chan School of Public Health

2 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And WallThickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates by Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications 2"

3 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications by 3"

4 Objectives " 1. To raise awareness within the fire service about enlargement of the heart (including cardiomegaly and left ventricular (LV) hypertrophy) and how it increases the risk of developing cardiovascular disease (CVD) and on-duty sudden cardiac death (SCD) 2. To summarize the current challenges we face in the identification of cardiac enlargement in active firefighters according to the method of assessment (see Chapter 1)

5 Objectives " 3. To estimate how common cardiac enlargement is among career US firefighters by combining the use of different imaging modalities (see Chapters 2 and 3) 4. To identify the most important predictors of LV mass in career male firefighters in the US so that more accurate medical screening programs can be implemented (see Chapter 4) 5. To translate current understanding of research to practical recommendations that the fire service can champion in the areas of medical evaluations, fitness goals, and behavioral health changes

6 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates by Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications 6"

7 CVD'in'the'US'Fire'Service' Cardiovascular Disease (CVD) is the leading cause of on-duty deaths in US firefighters and a costly cause of morbidity (45% on-duty Deaths). For every fatal on-duty CVD event, there are an estimated additional nonfatal events. Recognition of Cardiovascular Stressors has led to Heart Presumption laws in 37 / 50 states and 2 Canadian Provinces. 7"

8 Physically'Demanding'&'Psychologically'Stressful'Work' 'Can'Trigger'CVD'in'Vulnerable'Individuals' Strenuous'work' Climbing"stairs" Forcible"entry" Search"and"rescue" Heavy'PPE" >"22"kg" "Metabolic""work" Heat""dissipa?on" Hot'and'Dangerous' Environment' Over"100º"C"rou?nely" Chao?c" Low"visibility" 8"

9 On-Duty Heart Events - NOT random in time (duty, hour, season) - NOT random among FF & LEO - MOST could be Prevented Triggering on Underlying Disease 9"

10 Adapted from Soteriades et al. Cardiology in Review "

11 ' '!!! Striking!Evidence'! LVH/cardiomegaly!plays!a!major!role! in!cvd!events!in!us!fire!service! 11"

12 LVH/cardiomegaly'plays'a'major'role'in'CVD'events'in'US'fire'service" Evidence for LVH in 76% of the autopsies of CHD deaths. LVH/cardiomegaly was mentioned in 60% of the autopsies. (Kales et al. Environmental Health 2003) (Geibe et al. Amer J Cardiol 2008) Among male SCD 81% had evidence of cardiomegaly. (Tavora et al. Pathology 2012) 12"

13 Sudden'Cardiac'Death'among'Firefighters' 45'Year'of'Age'in'the'United'States' Jang'J,'Teehan'D,'Farioli'A,'Smith'D,'Kales'SN.'2013" 13"

14 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates by Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications 14"

15 LeX'Ventricular'Mass'(LVM)'" There is a consensus that the presence of LVH is best determined by estimating the LVM. LVM occupies a unique place among CVD risk factors: determined by established risk factors (obesity, blood pressure, tobacco use) a strong independent predictor of CV events an increase in LVM is associated with a higher incidence of CV events 15"

16 LeX'Ventricular'Mass'' ECHO'&'CMR" Echocardiography (ECHO) and Cardiac magnetic Resonance (CMR) are the two most frequently used imaging modalities for the assessment of LVM. CMR is considered the GOLD standard. ECHO is well validated, widely available. ECHO-derived LVM is usually performed in clinical practice and has shown prediction ability to CV outcomes. 16"

17 LeX'Ventricular'Mass'Indices'' Wide distribution of LVM values in a healthy population. Absolute LVM values are limited by not accounting for physiologic variations related to body size. LVM index (LVMi) is usually derived by dividing LVM with a body size parameter (body surface area, height to an allometric power). LVH is defined by an LVMi greater than some specified cutoff value. The definition of LVH and its performance as a CV risk predictor is strongly related to the LVM indexing method. 17"

18 LeX'Ventricular'Mass'Indices'' Indexing to BSA 1 st normalization process used Underestimates the prevalence of LVH in obese and overweight individuals Indexing to height 1.7 Higher sensitivity than index to BSA in identifying obesity-related LVH Best description of the LVM-body size relationship Consistently associated with cardiovascular events and all-cause death 18"

19 '''''''''''''''''The'phenomenon'of'Athlete s'heart' Adaptive rather than pathological hypertrophy. Type of training (strength-endurance) Strength training alone almost never causes physiologic hypertrophy High-intensity endurance training may result in LVM values that overlap with the LVH range, especially among males 19"

20 '''''''''''''''''The'phenomenon'of'Athlete s'heart' Reference ranges from only sedentary people - likelihood of classifying athletes as mild to moderate LV Hypertrophy If trained athletes are included in Control population -the upper limit of normal range for LVM is higher and there is a decreased sensitivity for detecting pathologic LVH 20"

21 LeX'Ventricular'Mass'Indices'&'Hypertrophy'Defini^on'" LVMi Cutoff Values Women Men ECHO LVM/BSA >95 (g/m 2 ) >115 (g/m 2 ) LVM/height 1.7 >60 (g/m 1.7 ) >81(g/m 1.7 ) LVM/height 2.7 >47(g/m 2.7 ) >50(g/m 2.7 ) CMR LVM/BSA >84.6 (g/m 2 ) >106.2 (g/m 2 ) LVM/height 1.7 >60(g/m 1.7 ) >80(g/m 1.7 ) LVM/height 2.7 >38 (g/m 2.7 ) >45.1(g/m 2.7 ) Armstrong et al. Echocardiography "

22 Heart''Weight'' Challenges: Scientific evidence available relies largely on older autopsy studies ( s) Some studies have not excluded hearts with pathologic changes Ethnicity-specific reference standards Reference values can only be valid for a limited period of time Autopsies vary considerably 22"

23 Heart''Weight'' Reference Ranges General Population (Injury deaths with normal hearts) Men: Heart weight 365 +/- 71 grams Women: Heart weight 312 +/- 78 grams Grandmaison et al. Forensic Science Intl.2001 Average heart weight is found to be 30-40% greater in men than in women with a similar body weight. 23"

24 Rela^onship'of''LVM'to'Heart'Weight' " Most autopsies do not report individual ventricular weight, but rather they report the total heart weight. Paucity of direct comparisons between autopsy and imaging data. The limited data available suggest that LVM accounts for a much greater proportion of total cardiac mass in diseased hearts as compared to normal hearts. " 24"

25 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications by 25"

26 Study"Popula?on"1"

27 Defining'Cardiac'Enlargement'" 27"

28 Study'Popula^on'1' Ac^ve'Career'Firefighters'" LVH definitions per ECHO & CMR Weighted analysis was performed Weights were calculated based on the total number of risk factors per subject with the technique of inverse probability weighting 28"

29 Inclusion Criteria (1) age 65 years (2) duty-related death, and Study Population 2! Non cardiac Traumatic Fatalities" (3) cause of death determined by autopsy to be due to blunt trauma, burns, or asphyxiation and not related to any cardiovascular pathologic entity. Only male autopsy reports were included in this study. [293 reports for main analyses] Sensitivity analyses with data from all 353 autopsy records, assuming a BMI of 25 kg/m 2 and then 27 kg/m 2 for all 60 records with missing BMI information. " " 29"

30 Defining'Cardiac'Enlargement'" 30"

31 Non'cardiac'Trauma^c'Fatali^es" Cardiomegaly/LVH definitions per autopsies 31"

32 Purpose & Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications by 32"

33 LVH'Prevalence'Es^mates'by'ECHO'&'CMR' ECHO LVH Criteria per imaging modality LVM (>225g) Posterior Wall Thickness ( 1.2cm ) Study Sample (N=393) LVH (n,%) Study Sample unweighted 58 (15.3) 146 (14.1) 61 (16.0) 136 (13.1) Septal Wall Thickness 140 (36.7) 341 (32.8) ( 1.2cm ) LVM/BSA 13 (3.4) 34 (3.3) (>115 g/m 2 ) LVM/Height (18.7) 181 (17.5) (>81g/m 1.7 ) LVM/Height 2.7 (>50g/m 2.7 ) 34 (9.1) 90 (8.7) CMR LVM (>203.5g) 4 (1.1) 9 (1.0) Posterior Wall Thickness ( 1.2cm ) 21 (6.0) 50 (5.3) LVM/BSA (>106.2 g/m 2 ) 0 (0.0) 0 (0.0) LVM/Height 1.7 (>80g/m 1.7 ) 2 (0.6) 3 (0.4) LVM/Height 2.7 (>45.1g/m 1.7 ) 1 (0.3) 2 (0.2) 33"

34 Noncardiac'Trauma^c'Fatali^es" Cardiomegaly LVH & Cardiomegaly Criteria Quantitative Definition ( 450 g) Qualitative Definition (Heart size abnormality noted) LVH & Cardiomegaly Prevalence n(%) 103 (33.8) 60 (19.6) LVH Quantitative Definition ( 1.2cm ) 121 (41.5) Qualitative Definition (Increased Wall Thickness noted) 44 (13.7) 34"

35 Noncardiac'Trauma^c'Fatali^es" Heart weight and LV wall thickness steadily increased with increasing age and BMI. Both remained significant after adjusting for the other parameter. " 35"

36 Conclusions Significant potential impact of the choices of the clinicians or the researchers Criteria by CMR measurements presented unrealistically low prevalence estimates BMI was a major driver of heart weight Measurement of LV wall thickness on average was similar across imaging and autopsies Urgent need for outcome-based studies Standardization of the forms of the autopsy reports across protocols and jurisdictions 36"

37 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications by 37"

38 Mul^variate'Linear'Regression'Models' A 1-unit decrease in BMI was associated with 1 unit (kg/m 1.7 ) reduction of LVM/ height 1.7 after adjustment for age, HTN, OSA risk and cardiorespiratory fitness. BMI to be the strongest and consistent independent predictor of LVM indexed by height to the allometric powers of 1.7 and "

39 Objectives Background Overview' Current Challenges in the Identification of Cardiac Enlargement by Imaging Modalities and Autopsies Methods Study Population 1 (Non-Invasive Assessment/ Imaging) Study Population 2: Direct Measures Of Heart Weight And Wall Thickness (Autopsy Reports) Cardiac Enlargement in U.S. Firefighters: Prevalence Estimates by Echocardiography, Cardiac Magnetic Resonance & Autopsies Effect of Body Mass Index on Left Ventricular Mass in Career Male Firefighters Conclusions, Recommendations & Clinical Implications 39"

40 Conclusions,'Recommenda^ons'&'Clinical'Implica^ons'' " Korre M, Kales SN et al Am J Cardiol 2016: BMI is driving LVM. Korre M, Kales SN et al J Clin Exp Cardiolog 2016: BMI is driving LV wall thickness and heart weight. Korre M, Kales SN et al J Integ Cardiolog 2016: LVM accounts for a greater proportion of total heart weight in diseased hearts Take Home Message for Clinicians: Implement targeted screening for LVH and cardiomegaly for obese firefighters, as well as those with uncontrolled or chronic hypertension or obstructive sleep apnea

41 Conclusions,'Recommenda^ons'&'Clinical'Implica^ons'' " Previous Study (Yang et al.2013): SCD among younger firefighters was largely driven by an increased cardiac mass in SCD victims compared to controls. 2/3 of SCD victims were obese Korre M, Kales SN et al Am J Cardiol 2016: BMI is driving LVM. Take Home Message : Decreasing obesity in the fire service will improve firefighters CV risk profiles, including their risk of LVH. Significant reduction in on-duty CVD events, particularly SCD.

42 Let s together lead the way forward to improve health & employment outcomes among US Firefighters.

43 Dr.'Stefanos'N.Kales' Harvard'T.H'Chan'School'of'Public'Health'" EOME"program"" Harvard"Research"Team"" " Skidmore'College' Dr."Denise"Smith" Ms"Jeannie"Haller""" Skidmore"Research"Team"" " University'of'Bologna'' Dr."Andrea"Farioli" " University'of'Brasilia/HSPH' Dr."Luiz"G.G."Porto"" " Na^onal'Fallen'Firefighter'Founda^on'' Acknowledgments Public'Safety'Medical' Dr."Steven"Moffaa" Ms"Lora"Lex" Ms"Carolyn"Muegge" Mr"Nelson"Hale" " Indiana'University'' Dr."Richard"Kovacs" Dr."Ronald"Mastouri"" Ms"Roxanne"Kovacs" ' All'par^cipa^ng'Firefighters,Collabora^ng' Ci^es,'Clinics,'Researchers' ' Funding'Sources' FEMA"AFG"program s"award"emww2011w FPW00663"(PI:"Dr."S.N.Kales)"&" EMWW2013WFPW00749"(PI:"Dr."D.L.Smith)."" " Harvard"Tui?on"Scholarship" " Research"Assistantship"_SNK"research"team"""" 43"

44 Thank You!! 44"