Ischemic Heart Disease
With increasing age, narrowings may develop in the coronary arteries that lead to the heart. This reduced blood supply causes ischemia (insufficient blood supply for the heart's work) and may produce chest pain or angina. Sudden blockages will result in a heart attack, also known as myocardial infarction (MI).
The incidence of heart disease begins to increase in men after the age of forty-five and in women after the age of fifty-five, but the rate for women tends to equal that of men after the age of seventy. It was once believed that hormone replacement therapy would protect women from heart disease, but more recent studies suggest this is not true. The Heart and Estrogen/Progestin Replacement Study (HERS) showed no benefit, as well as an increased risk of blood clots in the leg (deep vein thrombosis) and of gallbladder disease. Along with age, male gender, family history, and ethnicity are nonmodifiable risk factors for heart disease.
The most modifiable risk factor for heart disease is smoking, which leads to increased obstruction of the coronary arteries. Each cigarette also causes spasms in these arteries. Smokers have twice the risk of heart attacks as nonsmokers, and death rates for heavy smokers are two to three times that of nonsmokers. Quitting smoking at any age likely confers benefit. This implies that it reduces disease progression and reduces the risk of MI and stroke; it also leads to a 25 to 50 percent reduction in mortality and recurrent heart attacks (MI).
There are many aids available to help quit smoking. These include nicotine gum (although people with dentures find the gum difficult to use). A nicotine patch is also available. Success rates for quitting using nicotine replacement are 18 to 25 percent, compared to 5 to 10 percent without nicotine replacement. Patients with heart disease may be concerned that nicotine replacement is not safe (potential dangers are dream abnormalities, insomnia, and application site reaction, also known as patch-rash), but if the options are replacement therapy or continued smoking, replacement therapy is probably safer.
Other aids in quitting smoking include medication (e.g., Bupropion, cloridine, mortiptyline) that can help relieve the agitation associated with quitting. Success rates are in the range of 30 percent. Other aids include hypnosis, acupuncture, laser therapy, and relaxation therapy. It is not important which method is chosen; what is important is the need to stop smoking.
The next major modifiable risk factor is diabetes. Diabetes, like heart disease, also increases with age, and prevalence approaches 10 to 20 percent in people over the age of sixty-five. People with diabetes have a two- to four-fold increased risk of coronary artery disease. While good control of diabetes probably reduces risk for heart disease, it seems that control of blood pressure is even more important for diabetics in reducing the risk of developing heart disease.
High blood pressure has also been strongly associated with heart disease, and it also increases with aging. Treating hypertension with low-dose thiazide diuretics and long-acting dihydropyridine calcium channel blockers has been shown to reduce heart attack, stroke, and death for people over the age of sixty.
Cholesterol has also been shown to be a significant risk factor for increasing coronary artery disease (CAD). The HMG-CoA reductase inhibitors (statins) have consistently shown a 20 to 30 percent reduction in heart attacks and death. The cholesterol-lowering trials of statins excluded elderly patients over the age of seventy-five, but the medications are still considered safe. This is because there is wide experience with statins outside the elderly community, randomized trials have proven safe, and side effects have very rarely been reported. In addition, older patients have the greatest risk and suffer the greatest burden from heart attacks and strokes and therefore have the most to gain from the use of these drugs.
Obesity and physical inactivity are also associated with heart disease. Regular physical activity five to seven times per week for twenty to thirty minutes a day can reduce the risk of heart disease by 20 percent. This may pose problems for some older adults, as there is an increase in arthritis in the older population, which can limit their physical ability. The use of a stationary bicycle allows people to sit while exercising and takes the weight off the lower joints, as does swimming and water exercise.
The use of antioxidants such as vitamin E and beta carotene have proven to be of no benefit in reducing heart disease. Fish oil supplements, which contain polyunsaturated fatty acids, have been shown to have a small but significant benefit in those with established heart disease. A Mediterranean-style diet has also been shown to be protective for heart disease. Such a diet includes "more bread, more root vegetables and green vegetables, more fish, less meat (beef, lamb, and pork to be replaced with poultry), no day without fruit, and butter and cream to be replaced with. . . a rapeseed (canola) oil-based margarine" (de Lorgeril, 1994).
Angina is classified into four stages. Functional class I indicates symptoms only with vigorous exertion. Class II indicates symptoms with moderate exertion; such as climbing a flight of stairs, or walking more than two blocks. Functional class III occurs with less activity, and functional class IV occurs at rest or with very low levels of activity such as walking around the room. The classic symptoms of angina are central pressure or chest pain, although the full range of symptoms felt may also include burning; a feeling of heaviness, squeezing, tightness, or fullness; an ache or sharp pain; or even no chest symptoms at all. The chest pain often radiates up into the shoulder and neck and down the arm (the left more so than right). It may also present in the upper abdomen, back, and ears or jaw as well. Other typical features include shortness of breath, a cold sweat (diaphoresis), weakness, nausea and vomiting, or even a loss of consciousness. Typically, these symptoms occur with exertion and are resolved with rest. If there is a change in symptoms with less activity or if they are more severe or prolonged, then the condition is considered unstable angina. Worsening of symptoms is related to an increase in the amount of obstruction of the coronary arteries. At the extreme of this spectrum of acute ischemic syndromes or unstable angina is a myocardial infarction, or heart attack. This occurs when the circulation is insufficient to keep the heart muscle alive. Typically, it is associated with a blood clot forming on a partial obstruction in the coronary arteries.
Unfortunately, as people get older they are less likely to present with typical symptoms. They may not have pain or discomfort; problems with nausea, diaphoresis, and weakness may not be attributed to a heart problem; and, frequently, people do not seek attention. Also, diabetics and women are more prone not to have typical symptoms, resulting in misdiagnosis and undertreatment.
More alarmingly, the rates of death from heart attack increase sharply with increasing age. Mortality under the age of sixty-five is probably in the range of 4 percent. Mortality over the age of seventy-five climbs to 20 percent. Complications after an infarct are also increased in the elderly.
When presenting with a heart attack, patients are treated initially with aspirin. Provided there has been no recent surgery or problems with bleeding, they may also be treated with medication to dissolve the clot causing the heart attack. Best results occur if treated within an hour after the onset of symptoms, but benefits are still seen even six to twelve hours after the onset of pain. These thrombolytic medications (e.g., streptokinase, tissue plasminogen activator, reteplase, tenecteplase) have been shown to significantly reduce death, but they are also associated with an increased risk of bleeding. This can be controlled, however, unless there is bleeding in the head, which is almost always fatal. The benefits of the medication outweigh the risks, and, given that older patients have a much greater risk of dying, they also enjoy a much greater absolute benefit from this therapy. For two to three days following an infarct, patients are treated with intravenous medication or an injection of heparin, which keeps the blood thin.
Another possible treatment at the time of a myocardial infarction is angioplasty. Angioplasty has the greatest success for treating MIs, but requires rapid availability and experienced physicians.
Other medications given to patients to reduce mortality after a heart attack are beta blockers and ACE inhibitors. Calcium channel blockers and nitroglycerin under the tongue, in a pill or patch form, or even intravenously, help control pain with acute ischemic syndromes.
With an uncomplicated heart attack, people can expect to be in the hospital five to seven days. After one to two days of rest, patients start to mobilize. This is done while being monitored. Medications are adjusted as tolerated, and patients generally have an assessment of their heart function by an echocardiogram (ultrasound of the heart) or a wall motion study (a nuclear X-ray). Prior to going home, most patients have an exercise stress test in which they walk on a treadmill while heart rate, blood pressure, and any changes in the electrocardiogram, as well as any recurrence of symptoms, are monitored. If these occur at low levels of activity, there is increased risk and more aggressive investigations or treatment are warranted. If not, the patient is considered low risk and should be safe for discharge.
Following discharge, patients can gradually increase their physical activity, watching for any recurrence of symptoms. Walking for five to ten minutes twice a day, and gradually increasing this up to thirty minutes twice a day, and then to forty to sixty minutes of walking or exercise once a day is recommended.