HYPERTENSION affects about 50 million Americans, but 30% of these patients don't know they have it and fewer than half have their blood pressure (BP) under control. Without proper treatment, many of these people will face devastating complications, including myocardial infarction, stroke, kidney failure, and blindness.
The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure has developed a guideline to prevent, recognize, and treat hypertension. The first step is to recognize the new classifications of hypertension. Normal BP is defined as a systolic BP less than 120 mm Hg and a diastolic BP of less than 80 mm Hg.
That's a departure from the previous guidelines, which had normal as a BP less than 140/90 mm Hg. In fact, if your patient's BP is between 120 and 139 systolic or between 80 and 89 diastolic, he's considered to have prehypertension. A BP of 140 mm Hg or greater systolic or 90 mm Hg or greater diastolic is considered hypertension. If your patient has diabetes or chronic kidney disease, a BP greater than 130/80 mm Hg is considered hypertension.
The treatment goals for hypertension are to bring BP below 140/90 mm Hg for patients without diabetes and below 130/80 mm Hg for those with diabetes. For all patients, the goal is a BP less than 120/80 mm Hg.
Types of hypertension
Hypertension falls into two classes: primary and secondary. Up to 95% of patients have primary hypertension, which occurs when the sympathetic nervous system and the renin-angiotensin-aldosterone system are hyperactive, causing vasoconstriction and endothelial dysfunction. What causes the hyperactivity of these systems is unknown.
In secondary hypertension, the definitive cause of the hypertension is known. High-dose estrogen therapy, polycystic kidney disease, renal artery stenosis, primary hyperaldosteronism, Cushing's syndrome, hyperthyroidism, and pheochromocytoma are some of the causes of secondary hypertension.
Who's at risk?
Identifying who's at risk for developing hypertension and cardiovascular disease is one of the first steps in managing hypertension. Patients with a family history of hypertension and heart disease; those who are smokers, sedentary, or have a body mass index of 30 kg/m2 or greater; and patients with a history of dyslipidemia, diabetes, or albumin in their urine are at higher risk of developing hypertension and cardiovascular disease. Men over age 55 and women over age 65 or who are postmenopausal are at increased risk of developing hypertension and cardiovascular disease. Taking nonsteroidal anti-inflammatory drugs regularly or (for women) taking estrogen-containing contraceptives also increases the risk.
Taking the right steps
To manage hypertension effectively, your patient will need to focus first on lifestyle modifications; if they don't work, he'll need medication. The following lifestyle modifications are recommended:
* Lose excess weight. BMI should be between 18.5 and 24.9 kg/m2. For every 22 lbs (10 kg) of weight lost, the BP will drop 5 to 20 mm Hg. Teach your patient to follow a reduced-calorie diet low in saturated fat and cholesterol. His total fat intake should be 25% to 35% of his total calories, with saturated fat accounting for less than 7% of total fat intake. He should adopt the Dietary Approaches to Stop Hypertension (DASH) eating plan to decrease cholesterol intake. The DASH plan has been found to decrease BP by 8 to 14 mm Hg. It's available online at http://www.nhlbi.nih.gov/health/public/heart/hbp/dash.
* Cut back on salt. Too much sodium in the diet can cause fluid retention and increase BP. Older adults and African-Americans are especially sensitive to salt. Advise your patient to ignore the salt shaker, read food labels, and limit sodium consumption to less than 2.4 grams per day. A low-sodium diet can reduce BP by 2 to 8 mm Hg.
* Exercise regularly. The American Heart Association recommends that everyone should engage in at least 30 minutes of aerobic activity on most days of the week. This helps control BP and can help patients lose weight. Regular exercise can decrease the BP by 4 to 9 mm Hg.
* Stop smoking. Not only is tobacco use a leading cause of lung cancer, but it's also the leading cause of cardiovascular disease. Encourage your patient to speak to his health care provider about a smoking cessation program.
If your patient's BP isn't adequately controlled with lifestyle modifications, he'll need drug therapy. For best results, most patients need two or more drugs that tackle hypertension via different mechanisms. Thiazide diuretics are usually the first line of therapy. There are exceptions, of course. For patients with diabetes, heart failure or kidney failure, an angiotensin-converting enzyme (ACE) inhibitor should be used as a first-line agent. Many times the ACE inhibitor is combined with a diuretic. Angiotensin receptor blockers (ARBs) can be used if the patient can't take an ACE inhibitor (some patients experience a dry cough on this drug). Both ACE inhibitors and ARBs help maintain renal function in patients with diabetes.
For patients with hypertension and stable angina, a beta-blocker or calcium channel blocker may be used. For patients with acute coronary syndromes, beta-blockers and ACE inhibitors are commonly used. For patients with heart failure, ACE inhibitors, diuretics, aldosterone antagonists, and beta-blockers are commonly used.
Certain patient populations react differently to medications than others. We know that African-Americans often do better on combination therapy and that older adults may be more vulnerable to adverse drug effects.
By understanding how to spot hypertensive patients, you can help them get their BP under control and avoid serious complications down the road.
Anne Woods is clinical director of journals at Lippincott Williams & Wilkins in Ambler, Pa., a per diem nurse practitioner at Chester County Hospital in West Chester, Pa., and an adjunct faculty member at Immaculata (Pa.) University.