Male Endurance Athletes Often Have Undiagnosed Hypertension and Unstable CAD

Becky McCall

June 08, 2021

Hypertension is prevalent, underdiagnosed, and significantly associated with the presence of unstable coronary artery disease (CAD), shows a prospective study of healthy, middle-aged, male master endurance athletes such as runners, cyclists, and swimmers.

More than a quarter of athletes were found to have resting hypertension, and in those with high normal blood pressure, more than 50% had abnormal blood pressure parameters.

The study also found that systolic blood pressure (SBP) was the best predictor of CT coronary abnormalities in these athletes.

Cardiovascular Evaluation

Presenting at this week’s British Cardiovascular Society (BCS) virtual meeting, Dr Gemma Parry-Williams, St George's University of London, said: "These findings suggest that recommendations for cardiovascular evaluation of master athletes should consider a low threshold for exercise testing and ambulatory blood pressure monitoring for those with resting hypertension and even high normal blood pressure."

Current physical activity guidelines recommend a minimum of 30 minutes of moderate physical activity per day, 5 days per week, or 25 minutes of vigorous activity per day for 3 days per week. Endurance athletes exceed the usual recommendations for exercise by 15 to 20-fold.

There is known to be a reverse J-shaped dose–response relationship between lifetime exercise exposure and cardiovascular morbidity, but in some individuals who engage in endurance sports exercise at levels far beyond the recommendations, some of the benefits of exercise are lost, noted Dr Parry-Williams in a paper published earlier this year.

Risk Factor

Dr Martin Halle, is a specialist in internal medicine, cardiology and sports medicine, at the Technical University of Munich, Germany, as well as president, European Association of Preventive Cardiology (EAPC). Commenting on the work, he said, "I think that in general, hypertension in master athletes should be clearly regarded as a risk factor. It is often overlooked or neglected as these individuals are very fit, look healthy and themselves neglect elevated blood pressure levels and do not want to be treated by medication," he noted.

"In addition, exercise blood pressure should be assessed as well. Mostly, these athletes benefit from treatment by medication even with respect to their exercise performance," he told Medscape News UK.   

Also commenting, Dr Aaron Baggish, associate professor of medicine, Harvard Medical School, said: [The] abstract is interesting and spot on based on what we routinely see clinically.
 
"Hypertension is a common, under-diagnosed, and under-treated clinical problem in otherwise healthy athletic people. It is perhaps the most important opportunity we have for disease prevention and should be addressed with every patient at every clinical encounter," he told us.
 

Middle-aged Healthy Men Who Cycled, Ran, or Swam for Over 6 Hours Per Week

The role of hypertension in the pathophysiology of high coronary artery calcium (CAC) scores and other computed tomography (CT) markers, which are suggestive of high-risk CAD in male master endurance athletes, had yet to be evaluated, Dr Parry-Williams said, referring to the motivation for the study.

In the prospective, observational study, 214 healthy, male master endurance athletes, aged 40-65 years, with no known cardiovascular risk factors, nor co-morbidities, underwent examination including 24-hour ambulatory blood pressure monitoring during which time they were asked not to vigorously exercise, a maximal cardiopulmonary exercise test (CPET), CT calcium scoring, and a CT coronary angiogram (CTCA).

CT abnormalities characterised included the coronary artery calcium (CAC) score, coronary stenosis (significant if >50%), plaque morphology (calcified, soft and mixed plaque), and plaque vulnerability markers including spotty calcification, napkin ring sign, low attenuation plaque, positive remodelling, and plaque rupture.

Blood pressure cut-offs were set according to the 2019 European Society of Cardiology (ESC) hypertension guidelines: high normal was 130-139 mm Hg and/or 85-89 mm Hg; hypertension was >140 and/or >90 mm Hg, broken down into grades 1-3. Ambulatory hypertension was defined as any of following on 24-hour monitoring: 24 hour >130 and/or >80 mm Hg; diurnal >140 and/or >90 mm Hg; nocturnal >120 and/or >70 mm Hg. A hypertensive response to exercise was defined as a maximum of 220 mm Hg.

Men of average age 51 years who cycled, ran or swam, or did any combination of these for at least 6 hours per week (median 8.5 hours) and had a median Q risk score of 3.5% were included.

A Third of Patients Showed Unstable Plaque and Majority Low-Grade Hypertension

Dr Parry-Williams reported that according to CT data, 16% had a CAC score >100 Agatston units (considered adverse risk in the general population); 5% exhibited significant coronary stenosis; a third (32%) of all plaque morphologies were non-calcified (27% mixed and 5% soft); and 13% had additional plaque vulnerability markers.

"These results show that 32% had evidence of high risk or unstable plaque," said Dr Parry-Williams.

"More than a quarter [26%] of athletes showed resting hypertension and in those with high normal blood pressure we found that over 50% [53.74%] had abnormal blood pressure parameters [130/85 mm Hg]. Most of these are in the high normal [28.04%] or grade 1 hypertensive [20.56%] groups," she reported. "Importantly, this suggests that the majority of athletes have evidence of low-grade hypertension in this study."

Evidence of masked hypertension was also found. Further analysis showed that 41% of these athletes met criteria for ambulatory hypertension, with 15% having masked hypertension – so normal resting but abnormal ambulatory, and 12% showed a hypertensive response to exercise, 10% of whom had a normal resting blood pressure.

"This suggests that a significant proportion of these athletes have a normal resting blood pressure but abnormal parameters for blood pressure on further clinical evaluation," Dr Parry-Williams highlighted.

Further modelling of the risk associated with different markers including CAC score, coronary stenosis > 50%, and plaque vulnerability markers was carried out. Dr Parry-Williams found that for every 5mm Hg increase in resting blood pressure and nocturnal ambulatory blood pressure there is a significant increase in CAC score >100 Agatston units with odds ratios of 1.21 and 1.28 respectively.

With respect to stenosis > 50%, odds ratios for every 5mm Hg increase in maximum exercise systolic blood pressure (SBP), resting SBP, 24-hour ambulatory SBP, and nocturnal ambulatory SBP were 1.26, 1.31, 1.74 and 1.50, so increased SBP was associated with all parameters, with 24-hour ambulatory SBP being the most significant, said Dr Parry-Williams. A similar picture of significance was seen when all blood pressure parameters were analysed for association with plaque vulnerability markers (1.14 1.16, 1.36, 1.43 respectively).

"Again, ambulatory systolic blood pressure had the strongest significance so we can conclude that systolic blood pressure is the best predictor of CT coronary abnormalities," remarked Dr Parry-Williams.

Using further modelling and markers of plaque morphology, the analysis found that for calcified plaque there were no significant associations with blood pressure parameters compared to athletes without plaque. However, there was a significant association with soft and mixed plaque with nearly all blood pressure parameters.

"For 24-hour ambulatory systolic blood pressure, odds ratios were 1.86 and 1.46 for soft and mixed plaques respectively. We can conclude that blood pressure parameters are powerful predictors of vulnerable plaque morphology," said Dr Parry-Williams.

She noted that further studies were needed to further delineate the relationship between blood pressure and atherosclerosis in male master endurance athletes.  

Presented at the British Cardiovascular Society virtual conference June 7-10, 2021

COI: Dr Parry-Williams, Professor Halle, and Dr Baggish have declared no relevant conflicts of interest.

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