General Principles
- •
An estimated 76.4 million Americans over the age of 20 years have hypertension (HTN).
- •
HTN is the most common cardiovascular condition observed in competitive athletes.
- •
Athletes are usually considered to be free from cardiovascular disease because of their apparent high level of fitness.
- •
The overall incidence of HTN in athletes is approximately 50% less than that in the general population.
- •
Most cases are in the mild-to-moderate range.
- •
- •
HTN begins in young adulthood.
- •
Incidence increases with age.
- •
5%–10% in adults aged 20–30 years
- •
20%–35% in middle-aged adults
- •
>50% in adults aged over 60 years
- •
Residual lifetime risk of 90%
- •
- •
Almost 80% of adolescents with an elevated blood pressure (BP) (>142/92 mmHg) during preparticipation physical examinations have HTN.
- •
Classification of Hypertension (JNC-7)
- •
Progresses through three classifications ( Fig. 36.1 , Table 36.1 )
Figure 36.1
Causes of hypertension.
TABLE 36.1
CLASSIFICATION OF HYPERTENSION
Systolic (mmHg)
Diastolic (mmHg)
Normal
<120
<80
Prehypertension
120–139
80–89
Stage 1 hypertension
140–159
90–99
Stage 2 hypertension
≥160
≥100
Classification of blood pressure (BP) for adults aged ≥18 years. The classification is based on the mean of two or more appropriately measured seated BP readings on each of two or more office visits. In contrast with the classification provided in the JNC VI report, a new category designated prehypertension has been added, and stage 2 and 3 hypertension have been combined. Patients with prehypertension are at an increased risk of progression to hypertension; those in the 130/80 to 139/89 mmHg BP range are at twice the risk of developing hypertension as those with lower values.
Adapted from the Seventh Report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7). JAMA. 2003;289(19):2560-2575.
- •
Normal systolic BP is <120 mmHg and diastolic BP is <80 mmHg
- •
Prehypertension systolic BP is 120–139 mmHg and diastolic BP is 80–89 mmHg.
- •
Associated with increased cardiac output (CO), which primarily increases systolic BP, along with “normal” vascular total peripheral resistance (TPR)
- •
TPR is normal compared with resting levels in normotensives but inappropriately high when CO is elevated.
- •
In a nonhypertensive patient, TPR falls to compensate for a rise in CO, thereby maintaining normal BP.
- •
Lack of decrease in TPR is a result of impaired baroreceptor function.
- •
Baroreceptors are “reset” to maintain elevated rather than normal BP over time.
- •
- •
People with prehypertension are hypersensitive to catecholamine secretion and mental stress and have a hyperkinetic circulatory state.
- •
- •
Stage 1: systolic BP 140–159 mmHg and diastolic BP 90–99 mmHg
- •
Earliest stage and most common form detected in clinical settings
- •
Increased heart rate (HR) and CO and decreased TPR
- •
Decreased arterial lumen and disturbed autoregulation of blood flow in the periphery
- •
- •
Stage 2: systolic BP >160 mmHg and diastolic BP >100 mmHg
- •
Normal HR and CO
- •
Increased TPR
- •
Increased afterload leads to left ventricular hypertrophy (LVH) and increased diastolic BP. Severe and/or uncontrolled HTN may lead to the development of diastolic dysfunction and congestive heart failure.
- •
CO can no longer increase in response to exercise or other physiologic demands.
- •
Loss of contractility and congestive heart failure may develop.
- •
- •
- •
Most active individuals with HTN will fall into stage 1 or lower stage 2 (160s/100s).
- •
Those with comorbidities, such as diabetes or renal disease, should be treated at prehypertensive levels.
- •
Values for pediatric athletes are adjusted for age, gender, and height ( Table 36.2 ).
TABLE 36.2
CLASSIFICATION OF BLOOD PRESSURE FOR PEDIATRIC ATHLETES
Normal
Systolic and diastolic BP <90th percentile
Prehypertension
Systolic and/or diastolic BP ≥90th percentile but <95th percentile, or if BP exceeds 120/80 mmHg even if <90th percentile *
Stage I hypertension
Systolic and/or diastolic BP between the 95th percentile and 5 mmHg above the 99th percentile
Stage 2 hypertension
Systolic and/or diastolic BP, 99th percentile plus 5 mmHg
In children, the aforementioned definitions, based on the 2004 National High Blood Pressure Education Program Working Group (NHBPEP), are used to classify BP measurements. BP percentiles are based on gender, age, and height and on measurements on three separate occasions. The systolic and diastolic BP are of equal importance; if there is a disparity in category, the higher value determines severity of HTN.
From The National Heart, Lung, and Blood Institute. The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Pediatrics. 2004;114(2):555.
* A systolic pressure of 120 mmHg may typically occur at 12 years of age, whereas a diastolic pressure of 80 mmHg typically occurs at 16 years of age.
- •
Higher stages are associated with a higher risk of nonfatal and fatal cardiovascular disease as well as progressive renal disease ( Fig. 36.2 ).
Figure 36.2
Hypertension as risk factor for cardiovascular disease.
Clinical Pathophysiology of Hypertension
Primary Hypertension
- •
95% of cases
- •
Abnormal neuroreflexes and sympathetic control of peripheral resistance
- •
Abnormal renal and metabolic control of vascular volume and compliance
- •
Abnormal local smooth muscle and endothelial control of vascular resistance
- •
Sustained increases in systemic vascular resistance (SVR)
Secondary Hypertension
- •
5% of cases
- •
Younger patients or adults with rapid onset of HTN and no prior history of HTN
- •
BP is often poorly responsive to routine therapy.
Causes
- •
Renal (most common)
- •
Renovascular disease
- •
Increased renin stimulates conversion of angiotensin I to angiotensin II, which is a vasoconstrictor, as well as release of aldosterone
- •
Renal retention of sodium and water
- •
Fibromuscular dysplasia in younger patients and atherosclerosis in older patients
- •
- •
Renal parenchymal disease
- •
Inability of damaged kidneys to excrete sodium and water
- •
- •
- •
Endocrine
- •
Adrenal
- •
Pheochromocytoma
- •
Cushing syndrome
- •
Primary aldosteronism
- •
- •
Thyroid
- •
Hyperthyroidism
- •
Hypothyroidism
- •
- •
Acromegaly
- •
Hyperparathyroidism
- •
Estrogen
- •
Oral contraceptive pills (OCPs)
- •
5% will develop HTN over 5 years
- •
- •
- •
Other
- •
Coarctation of the aorta
- •
Obstructive sleep apnea
- •
Risk Factors for Hypertension
- •
Genetic factors
- •
Males more than females
- •
African-Americans more than Caucasians (2 : 1) with Asians at the lowest risk
- •
Family history (HTN twice as common if one or both parents have HTN)
- •
- •
Metabolic factors
- •
Obesity
- •
Glucose intolerance
- •
Endocrine disorders (see Causes )
- •
- •
Stress
- •
Environmental
- •
Social
- •
Leads to chronic neurogenic activation of the sympathetic nervous system
- •
- •
Behavioral factors
- •
High sodium intake
- •
Excessive alcohol consumption
- •
Drug abuse
- •
Recreational: cocaine or tobacco (chew)
- •
Ergogenic: stimulants or anabolic steroids
- •
- •
Diagnosis of Hypertension
Resting Blood Pressure (BP)
- •
Diagnosis of HTN is based on an average of two or more appropriately measured, seated BP readings >140/90 mmHg at each of two or more office visits (see Table 36.1 ).
- •
In children and adolescents, HTN is defined as average systolic or diastolic BP ≥95th percentile for age, gender, and height, measured on three separate occasions (see Table 36.2 ).
Environment During Measurement
- •
Measurement of BP should be performed in a standard measurement situation, preferably a quiet area.
- •
Let the athlete sit for a few minutes if possible.
- •
Repeat BP measurements if elevated.
- •
Choose the appropriate-size BP cuff. Several athletes will need a large cuff, and a thigh cuff should be available for very large athletes.
- •
The inflatable bag of the BP cuff should cover approximately 80% of the arm’s circumference.
- •
BP may be overestimated if the BP cuff is too small, while BP may be underestimated if the BP cuff is too big.
- •
- •
Avoid rapid deflation of the cuff.
“White Coat” Hypertension and Other Stress Phenomena
- •
Anxiety provoked by medical examination or other sources of mental stress can lead to artificially elevated BP, known as “white coat” HTN.
- •
Average of several readings is a better estimate of true BP.
- •
If initial BP is high, have the athlete rest for 5 minutes and repeat BP measurement.
- •
If BP remains elevated, check BP at least once per week for at least two additional visits.
- •
Averaged daily BP is a better predictor of later end-organ damage than random office BP.
- •
Ambulatory 24-hour BP monitoring (ABPM) may more accurately assess BP in people with variable readings in the office or at home.
- •
Home BP monitoring is readily available and correlates well with ABPM.
- •
Importance of accurate readings should be emphasized.
Clinical Evaluation
History
- •
Cardiovascular risk factors:
- •
Smoking
- •
Family history of cardiac disease in men younger than 55 years and women younger than 65 years
- •
Obesity
- •
Physical inactivity
- •
Diabetes
- •
Dyslipidemia
- •
- •
Diet and behavior:
- •
High sodium and saturated fat intake
- •
Alcohol consumption
- •
Herbs and supplements (particularly those for energy or weight loss)
- •
Drug use
- •
Over the counter (nonsteroidal anti-inflammatory drugs [NSAIDs], decongestants, caffeine, and diet pills)
- •
Prescription (glucocorticosteroids, erythropoietin, cyclosporine, methylphenidates, and amphetamines)
- •
Illicit (ergogenic aids, cocaine, and phencyclidine [PCP])
- •
- •
- •
Stress
- •
Review of systems to rule out secondary causes of HTN
Physical Examination
- •
Evaluate for secondary causes of HTN and end-organ damage
- •
Body mass index (BMI) often not useful in athletes because of higher levels of muscle mass
- •
Fundoscopic examination for retinopathy, as indicated by retinal hemorrhages or exudates, with or without papilledema ( Fig. 36.3 )
Figure 36.3
Eye grounds in hypertension.
- •
Thyroid
- •
Cardiovascular (pulses, murmurs, and bruits)
- •
Abdominal masses
- •
Peripheral edema
Laboratory Studies
- •
Hematocrit, Na+, K+, BUN, creatinine, glucose, lipid panel, urinalysis, EKG
- •
Further workup if suspicious of secondary causes
- •
Renal ultrasound recommended for pediatric athletes with established HTN
- •
Echocardiogram recommended in pediatric athletes with diabetes or renal disease associated with a BP between the 90 th and 94 th percentiles and all children with stage 2 HTN and BP in the ≥95 th percentile
- •
Exercise Stress Testing
- •
Although not routinely performed, exercise stress testing can be used to predict and differentiate types of HTN .
- •
Differentiating stages of HTN
- •
People with prehypertension start at higher resting levels than normotensives but do not show abnormally high BP levels during maximal exercise.
- •
Rapid elevation in systolic BP indicates established HTN.
- •
Hypertensives tend to have increased diastolic BP during and after exercise.
- •
- •
Predicting future HTN
- •
Exaggerated diastolic BP response to exercise (>95 th percentile) predicts the risk of new-onset HTN in men and women (2–4 times higher risk).
- •
Delayed recovery of systolic BP response is predictive of future HTN in men.
- •
Exercise BP may be a significant predictor of adverse cardiovascular events in high-risk patients.
- •
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
