Still a "silent killer" that typically has no symptoms and is rarely curable, hypertension continues to wreak cardiovascular havoc among Americans, causing strokes, heart attacks, and heart and kidney failure.
The latest government figures show that hypertension is on the rise, affecting 25% of adult Americans between the ages of 20 and 74 in 2002, up from 21.7% in 1994. The issue of when and how to treat hypertension became even more complicated in 2003 when the seventh report of the Joint National Committee (JNC 7), convened by the National High Blood Pressure Education Program, created a new blood pressure category it labeled "prehypertension." That category applies to at least 45 million Americans.
Accurate blood pressure measurement is essential for the proper diagnosis and treatment of hypertension.
Guidelines now urge physicians to screen more carefully for prehypertension to help fend off full-blown high blood pressure. That makes sense when you consider the dismal statistics of hypertension control: Only 30% of diagnosed patients—both those on and off drugs—get their blood pressure below 140/90 mm Hg.
According to Norman M. Kaplan, MACP, author of the classic textbook, "Kaplan's Clinical Hypertension," tracking hypertension in patients is beset with problems, beginning with the fact that the only way to diagnose it is through blood pressure measurement—which in itself, he said, is often fraught with error. (See "Getting hypertension treatment right.")
To maintain more accurate blood pressure numbers, Dr. Kaplan, who is clinical professor of internal medicine at the University of Texas Southwestern Medical Center in Dallas, urges his patients to take their own and to keep a diary of home readings. His patients fax those figures to his office.
When patients monitor their own blood pressure at home, he said, "they are more likely to stay with their medication—and with you." He has found home monitoring to be a key component of better adherence to treatment and better control. Other factors that can improve adherence include cutting patients' dosing of antihypertensives to once a day, he said—and spending time with patients in treatment.
"When it comes to hypertension, we say, 'OK, here's a pill, come back in four months and we'll get another blood pressure,' " Dr. Kaplan said. "I consider that to be inadequate."
This edition of ACP Observer Special Focus is designed to help optimize your ability to diagnose, treat and manage patients with essential hypertension.
- Normal blood pressure: Less than 120/80 mm Hg
- Prehypertension: 120-139/80-89 mm Hg
- Stage 1 hypertension: 140-159/90-99 mm Hg
- Stage 2 hypertension: Greater than or equal to 160/100 mm Hg
Because both prehypertension and hypertension usually have no initial symptoms, you need to screen all patients.
Focus on demographics commonly associated with the development of hypertension, including:
- family history of hypertension
- African-American ethnicity
- obesity and/or sedentary lifestyle
- consumption of too much sodium and/or alcohol
While protocols for measuring blood pressure are standardized, many health care professionals do not follow them. Improper measurement techniques or incorrect cuff size can distort true readings, leading to under- or overdiagnosis.
Keep in mind that blood pressure is affected by many factors, including emotional stress, nicotine and caffeine, discomfort from a full bladder, time of day, talking, and physical activity. Take measurements over several visits to confirm that blood pressure is persistently elevated.
Advise patients with prehypertension to change their eating and exercise habits. Counsel at-risk patients about the importance of weight loss and the following lifestyle changes:
- eating a diet rich in fruits, vegetables and low-fat dairy products, with reduced amounts of saturated and total fat.
- limiting dietary sodium to no more than 2,400 mg per day.
- limiting alcohol consumption to no more than two drinks per day for men, one per day for women.
- getting regular aerobic activity, such as brisk walking, at least 30 minutes a day.
Establish a hypertension diagnosis by documenting office systolic blood pressure of at least 140 mg Hg or diastolic of at least 90 mg Hg. Elevated systolic pressure indicates hypertension, even if diastolic pressure is normal, and vice versa. In older patients with hypertension, the systolic pressure is more likely to be elevated than the diastolic.
Base your diagnosis and your staging of the disease on an average of three sets of two or more readings taken two weeks to one month apart. After a high reading, blood pressure may be lower at subsequent visits because of familiarity; the resolution of an acute condition, such as a headache; or regression to the mean.
Consider having patients measure and record their blood pressure at home if you suspect "white coat" hypertension or if the diagnosis is uncertain.
Although home blood pressure measurement should not be the sole basis for making general treatment decisions, it can detect symptoms related to excessive blood pressure reduction and the effectiveness of therapy. It may also be better than office-based readings in predicting the development of target organ damage.
When patients test themselves at home, they need proper instruction. Common errors include not relaxing for at least five minutes before measurement, taking measurements while sick or symptomatic, and logging measurements incorrectly.
Stage the disease to determine cardiovascular risk and treatment. Stage correlates directly with cardiovascular risk, with risk beginning at 115/75 mm Hg and doubling with each 20/10 mm Hg increment, according to JNC 7. Hypertensive patients often have additional cardiac risk factors, including dyslipidemia, a family history of premature cardiovascular death, proteinuria and diabetes.
Use history, physical exam, lab testing and electrocardiogram (ECG) testing to assess for target organ damage, which can include heart attack, heart failure, stroke, nephropathy and retinopathy. Get the following studies in all diagnosed patients:
- blood chemistries, including glucose, creatinine and electrolytes;
- urinalysis; and
- lipid profile, including total and HDL cholesterol and triglycerides.
Increased serum creatinine and proteinuria indicate renal impairment, while low potassium could mean aldosterone excess. Other studies are useful in documenting comorbid disease. Echocardiography, for example, may help you document left ventricular hypertrophy (LVH) that can be missed on a standard 12-lead ECG.
Lifestyle changes constitute initial therapy for hypertensive patients who do not meet criteria for immediate drug treatment. Patients with stage 1 hypertension and no target organ damage or evidence of cardiovascular disease should try lifestyle modification alone for between six and 12 months before determining if any drug therapy is needed.
Relaxation therapies to relieve stress may lower blood pressure, although no controlled trials have shown persistent effects. And lifestyle modification should continue even if drug therapy becomes necessary.
Drug therapy is indicated for patients with stage 1 hypertension who fail to respond to lifestyle modifications, those with stage 2 hypertension, and those with target organ damage or diabetes mellitus with a systolic pressure of more than 129 mm Hg and/or a diastolic pressure of more than 84 mm Hg. Once-a-day dosing with long-acting formulations can boost adherence.
Consider a diuretic, beta-blocker or angiotensin converting enzyme (ACE) inhibitor for initial treatment of uncomplicated hypertension. Diuretics should generally be your first choice. One major study concluded that diuretics offer unsurpassed primary end point efficacy and better protection against heart failure than ACE inhibitors or calcium channel blockers. They also work better than ACE inhibitors for stroke and are cheaper. Substitute a drug from another class if patients do not respond to initial monotherapy.
Patients may need two or three medications to reach targeted blood pressure goals-and you should consider combination therapy at the outset in untreated patients who present with stage 2 hypertension.
When prescribing more than one drug, first consider a fixed-dose combination product of thiazide diuretic with an ACE inhibitor, angiotensin receptor blocker (ARB), beta-blocker or calcium channel blocker. If a fixed-dose product doesn't contain the anticipated needed doses of individual agents, try a diuretic with a concurrent ACE inhibitor, ARB, beta-blocker or calcium channel blocker.
You also need to individualize therapy for patients with specific comorbidities. (Also see "Treating hypertension and
- ACE inhibitors or ARBs for diabetes mellitus and for renal failure, particularly when proteinuria is present.
- ACE inhibitors or ARBs, diuretics, cardioselective beta-blockers and aldosterone antagonists for heart failure.
- Beta-blockers and ACE inhibitors or ARBs for patients with previous heart attack.
- Beta-blockers or ARBs for atrial arrhythmias, familial tremor, hyperthyroidism, migraine and preoperative hypertension.
- Calcium antagonists for atrial arrhythmias.
- Diuretics or long-acting calcium antagonists in older patients with isolated systolic hypertension.
- ARBs for older patients with LVH.
- Thiazides for osteoporosis.
- Alpha-blockers for prostatism.
Choice of drugs may depend on patient-related factors and comorbidities. African Americans may respond better to monotherapy with diuretics and calcium antagonists than with beta-blockers or ACE inhibitors. In patients with a serum creatinine of less than 2.0 mg/dL in men and less than 1.6 mg/dL in women, a morning dose of hydrochlorothiazide may be effective.
However, in patients with impaired renal function, a single morning dose of metolazone may be preferable to multiple doses of short-acting loop diuretics. Because beta-blockers may exacerbate airway constriction, you may not want to use them in hypertensive patients with asthma or chronic bronchitis.
Side effects are often dose-related. Instead of using maximum doses of antihypertensive drugs, consider using drugs in the middle range of manufacturers' recommendations and switch to a different agent if hypertension remains uncontrolled.
PATIENT EDUCATION AND FOLLOW UP
Studies show that only 50% of patients who start hypertension treatment still adhere to therapy after one year, so impress patients with how important treatment is. When available, enlist a care manager to help patients learn about hypertension and therapy.
Continue to encourage patients who are overweight to lose weight. Teach patients who could benefit from home blood-pressure monitoring how to properly use a measuring device, and check the accuracy of their device against the office sphygmomanometer.
And encourage home-monitoring patients to report data by phone, e-mail or fax so you can make appropriate therapeutic changes. Patients who feel their clinician takes a personal interest in their treatment are more likely to adhere to therapy.
If response to maximum therapy is inadequate, consider white coat hypertension; suboptimal adherence; volume overload; concomitant drug-related causes, such as use of nonsteroidal anti-inflammatory drugs; associated conditions, such as smoking or sleep apnea; and secondary hypertension.
You should also monitor patients for cholesterol, glucose and electrolyte problems as they age or gain weight while taking antihypertensive therapy.
Patients should be referred to a hypertension or other specialist in the following cases:
- when blood pressure is not controlled within a year of diagnosis;
- when multidrug therapy is ineffective;
- for management of advanced complications or complex comordibities; and
- for comanagement of secondary hypertension, including Cushing's disease, primary hyperaldosteronism and pheochromocytoma.
|Access to PIER's essential hypertension module is online.|
The information included herein should never be used as a substitute of clinical judgment and does not represent an official position of ACP.
Hypertension specialist Raymond R. Townsend, MD, is the first to admit he can get preachy about the need to properly measure patients' blood pressure. According to Dr. Townsend, director of the hypertension program at Philadelphia's Hospital of the University of Pennsylvania and the author of the PIER module on essential hypertension, most physicians and office staff are too rushed to take the time to do measurement right. His solution? He cuffs his own patients.
Dr. Townsend spoke with ACP Observer.
On treatment approaches:
Blood pressure is just one factor in target organ damage. For years, we treated it in a vacuum, letting people continue to smoke and not exercise. Now, we need to treat cardiovascular issues as a package, which takes more than 15-minute office visits, and physicians need help.
We don't have good prevention support, particularly from insurers. One study on mild hypertension found that it takes 15 hours of one-on-one time with a good dietitian and a strong cheerleading base to really alter patients' food intake. It takes a lot of work.
On correct blood pressure measurement:
If you're going to treat someone, take blood pressure the way you're supposed to. A medical technologist, as a rule, may be the least well trained to do this right, but is often the one performing this pivotal measurement.
To manage blood pressure ideally, I would have a fulltime dietitian and a fulltime nurse or nurse practitioner to measure blood pressure and provide lifestyle advice—they're less threatening.
On research developments:
The genetics of hypertension are unfolding—but only a handful of single gene disorders cause high blood pressure, and they are rare. We think that most genes contribute only one or two points toward that 140, so most genetic changes have small effects. Consequently, it appears that hypertension has a substantial environmental as well as genetic component.
We are working on better ways to assess risk from high blood pressure. For example, the 'speed' at which the pulse travels through the circulation may be a good predictor for development of stroke or heart failure. Moreover, measuring blood pressure in the aorta may provide a better reflection of what the heart actually responds to. Knowing this kind of information may help us understand why some drugs, like angiotensin receptor blockers, may have a more favorable effect on target organs.
When diagnosing or treating hypertension, it's essential to get a true reading. Yet many health care professionals don't follow the right steps when measuring patients' blood pressure.
According to the PIER module on essential hypertension, here are the proper steps for blood pressure measurement:
- Be sure patients know the person who is taking the measurement.
- Make sure patients have an empty bladder and no recent exposure to caffeine or cigarettes.
- Seat patients with back and feet support in a quiet environment and wait five minutes before measuring.
- Ensure that the cuff's bladder covers 80% of the arm circumference.
- Use the stethoscope on the arm at heart level.
- Use radial palpation or brachial pulse to estimate systolic pressure. Note the pressure at which the palpable pulse disappears.
- Completely deflate cuff and wait one minute.
- Take the pressure by rapidly inflating the cuff to at least 20 mm Hg above the previously palpated systolic pressure.
- Allow the mercury column to fall at a rate of about 2 millimeters per second. The first of two consecutively heard Korotkoff sounds is the systolic pressure; the final is the diastolic.
- Continue slow deflation another 10 mm Hg below the diastolic value you heard before completely deflating the cuff.
- Record blood pressure—if using a mercury column calibrated at 2-mm Hg increments--as systolic or diastolic, in mm Hg. Both numbers must be even.
- Measure blood pressure on both arms during at least one visit. You should use the arm with the higher value for subsequent measurement.
- Allow a full minute to pass between readings to allow venous engorgement from the last measurement to abate.
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