The Temporal Emergence of Cardiovascular Pathology in American-Style Football Players Open Access

Kim, Jonathan (Fall 2018)

Permanent URL: https://etd.library.emory.edu/concern/etds/ff365639s?locale=en
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Abstract

Background

Collegiate American-style football (ASF) participants are at increased risk for pathologic cardiovascular phenotypes. However, ASF participation rates are highest among high school athletes compared to other levels of ASF competition and data characterizing this population are lacking.This study sought to compare the cardiovascular response to high school versus collegiate ASF participation.

Methods 

ASF participants (High School, N = 61; Collegiate, N = 87) were studied longitudinally at pre- and post-season time points with 2-D echocardiography and vascular applanation tonometry. Primary outcome variables included: left ventricular mass index, left ventricular diastolic function (early relaxation velocity [E¢]), and arterial stiffness (pulse wave velocity).

Results

High school (17.1 ± 0.4 years old) and collegiate ASF participants (18 ± 0.4 years old) experienced similar left hypertrophy (Δleft ventricular mass high school = 10.5 ± 10 vs. collegiate = 11.2 ± 13.6 g/m2, P = 0.97). Among high school participants, left ventricular mass increased due to eccentric remodeling, which was associated with stable diastolic (ΔE¢= -0.3 ± 2.9 cm/s, P = 0.40)and vascular function (Δpulse wave velocity = -0.1 ± 0.6 m/s, P = 0.13). In contrast, collegiate ASF participants demonstrated concentric left ventricular remodeling with concomitant reductions in diastolic function (Δ E¢: -2.0 ± 2.7 cm/s, P <0.001)and increased arterial stiffness (Δpulse wave velocity: Δ0.2 ± 0.6 m/s, P = 0.002), changes that were driven by linemen position players who had the highest post-season weight (124 ± 10 kg) and systolic blood pressure (138.8 ± 11.2 mmHg). In multivariable linear mixed models adjusted for weight and systolic blood pressure and accounting for subject-specific random effects, increased weight predicted decreased E¢(mean difference in E¢from pre- to post-season estimated at-0.02 cm/s, P = 0.02) and increased pulse wave velocity (mean difference in PWV from pre- to post-season estimated at0.01 m/s, P <0.0001), while increased systolic blood pressure predicted increased left ventricular mass index (mean difference in indexed left ventricular mass from pre- to post-season estimated at0.15 kg/m2, P = 0.008)and increased pulse wave velocity (mean difference in PWV from pre- to post-season estimated at0.01 m/s, P <0.001). 

Conclusions

The transition from high school to college represents a clinically important temporal data point after which pathologic cardiovascular phenotypes are more evident among collegiate ASF participants. Future work aimed to clarify modifiable underlying mechanisms and long-term clinical implications is warranted. 

Table of Contents

INTRODUCTION..........................................................................................................................1

BACKGROUND.............................................................................................................................4

METHODS....................................................................................................................................6

RESULTS.....................................................................................................................................13

DISCUSSION...............................................................................................................................17

ACKNOWLEDGEMENTS.............................................................................................................21

REFERENCES…………………………………………………………………………..............................................23

TABLES / FIGURES

 Table 1. Baseline ASF participant characteristics..........................................................................i

 Table 2. Comparison of the longitudinal impact of high school versus collegiate 

                ASF participation………………………………..................................……………………………………ii

Table 3. Longitudinal comparison of high school versus collegiate linemen……...................…iii

Table 4.Predictors of primary outcome cardiac and vascular indices..……….……......................iv

Figure 1. Pre- to post-season change in the group mean diastolic LV tissue-Doppler E', PWV,

and LV mass index in high school and collegiate ASF participants………..……............................v 

Figure 2. One-way ANOVA comparison of post-season weight and SBP,cardiac structural

measures, and cardiovascular functional measures by player position..….…................................vi

Figure 3. Correlation analyses between post-season weight and post-season diastolic

function, PWV, and LV mass indexand post-season SBPand post-season diastolic function, 

PWV, and LV mass index in the combined high school and collegiate ASF cohort……….....………vii

Figure 4. High school versus collegiate ASF participation and differences in cardiac and vascular

phenotypes with proposed potential underlying mechanisms…........................................................…….viii

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