The functional capacity of organs reduces with age, resulting in decreased reserve, decreased compensation for stress, and increased incidence of coexisting diseases. Coexisting diseases further depress organ function, leading to even greater risk with surgical procedures. It is useful to review the common diseases encountered in the elderly.
The elderly patient is likely to suffer from altered cardiovascular function. Common disease states include coronary artery disease, cardiac valvular disease, congestive heart failure (CHF) and diastolic dysfunction, abnormal heart rhythm, systolic hypertension, and peripheral vascular disease.
The presence of coronary artery disease (CAD) increases with age. Anatomic CAD can be detected in more than 50% of people older than 70 years (Fig. 21-12).129 CAD in the aged is more severe and diffuse than in younger patients.130,131 There are differences in prevalence by gender: At 65 years of age, CAD is more prevalent in men than in women; by age 80, the prevalence of symptomatic congestive heart disease is nearly equivalent in men and women.131 Despite the high prevalence of anatomic CAD, only 10% to 20% of people older than 65 years carry a diagnosis of active CAD.131 This may be a result of misdiagnosis, lack of clinical symptoms because of inactivity, or lack of recognition of risk factors leading to diagnosis. One study reported that 37% of elderly patients had subclinical CAD, making it as common as clinically overt CAD in older adults.132 Furthermore, in this study, the presence of subclinical CAD was significant because it strongly predicted overt CAD, stroke, and mortality, even after adjustment for traditional cardiovascular risk factors.132 Despite the high prevalence of CAD, over the last 30 years in the United States, the CAD mortality rate has decreased significantly. This includes reduced recurrent myocardial infarction and increased postmyocardial infarction survival.
The percentage of chronic disease in a noninstitutionalized adult population older than 65 years (data averaged from 2000 to 2002). HTN, hypertension. [Adapted from Centers for Disease Control and Prevention, National Center for Health Statistics, National Health Interview Survey. http://www.agingstats.gov/-chartbook2004/healthstatus.html. Accessed June 19, 2006.]
The mitral and aortic valves may undergo significant age-related dysfunction. Common causes of valvular heart disease in the elderly are degenerative calcification, myxomatous degeneration, papillary muscle dysfunction, and infective endocarditis.133
The most frequent valvular lesion in the elderly is degenerative calcified aortic stenosis, with a prevalence of 2.5% at the age of 75 years and of almost 8% at 85 years.34Aortic regurgitation, mostly mild, was found in 29% of the entire study cohort. The severity of aortic stenosis in the elderly is often underestimated because its progression is so gradual and because symptoms may be attributed to normal aging, but stenosis severity may progress rapidly after age 80.135 Common causes of aortic valve stenosis are calcification of a congenital bicuspid aortic valve, degenerative aortic stenosis, and rheumatic heart disease (which may coexist with mitral valve disease).
Mitral valve disorders are common in the elderly, but the symptoms of mitral valve disease may be masked or exacerbated by coexistent CAD, pulmonary disease, hypertension, and other systemic disorders that commonly occur in older adults.136 Chronic mitral regurgitation is the most common type of mitral valve disease in the elderly. Rarely, isolated chronic mitral regurgitation occurs as a consequence of papillary muscle dysfunction after myocardial infarction. Chronic mitral regurgitation may also be a result of mitral annular calcification, myxomatous valve degeneration (with mitral valve prolapse), chordal rupture, and rheumatic heart disease. Mitral annular calcification occurs in approximately 6% of people older than 60 years, predominantly in women. The incidence of myxomatous valvular degeneration increases with age.
Mitral stenosis is a disease of younger patients because severe mitral stenosis usually leads to surgery or death before 65 years of age.136 If present, mitral stenosis is usually a result of rheumatic heart disease, a common condition when the current elderly population was young. Less commonly, mitral stenosis develops because of progressive mitral annular calcification.
Tricuspid regurgitation is usually a result of annular dilation caused by right ventricular failure (usually resulting from left-sided heart failure) or pulmonary hypertension. Unlike in younger patients, infective endocarditis is a less common cause of tricuspid valve dysfunction. Tricuspid stenosis is rare in the elderly.
Pulmonic valve disease as a consequence of primary valve dysfunction is rare but is usually secondary to pulmonary hypertension.
Concurrent Valvular Disease
Concomitant mitral and aortic valve disease is common in the elderly. About half of patients with rheumatic mitral regurgitation have associated aortic valve disease, usually aortic regurgitation. In one study, concurrent mitral regurgitation found in elderly patients undergoing isolated aortic valve replacement (AVR) was found to be an independent risk factor for long-term survival.137
Systolic Hypertension, Diastolic Dysfunction, and Congestive Heart Failure
As reviewed earlier, diastolic dysfunction and systolic hypertension are common and increase with aging. Ninety percent of Americans who have a healthy blood pressure at 55 years of age will have hypertension when they reach 75 years of age.138 Another common problem in the elderly is chronic heart failure, which can be divided into 2 broad categories: systolic heart failure and diastolic heart failure.139 Diastolic heart failure occurs more frequently in the elderly, in women, and in those with systolic hypertension, but it is less associated with concurrent CAD than systolic heart failure.139
Peripheral Vascular Disease
Peripheral vascular disease is not a normal consequence of aging but is associated with systemic atherosclerosis and other risk factors for CAD, many of which are commonly found in the aging patient. The prevalence of peripheral arterial disease increases with age and has a variable presentation: asymptomatic, associated with intermittent claudication, or associated with critical limb ischemia.140
Age-related changes in atrial chamber size and pressure, in left ventricular mass, and in catecholamine levels, in addition to increased incidence of CAD, contribute to a higher incidence of arrhythmias and conduction disturbances in the elderly. Common arrhythmias are atrial fibrillation, ectopic beats, and heart block.
Atrial fibrillation (AF) is among the most common arrhythmias seen in the general population.141 The prevalence of this condition is increasing and increases with age; it occurs in approximately 6% of people older than 65 years as compared with approximately 2% of people between 40 and 65 years of age.142 In all age groups, men are more affected than women. It is believed that by 2050, more than 5.6 million people will have AF and that more than 50% of those older than 85 years will have this condition.143 Multiple conditions predispose to AF, including structural heart disease, hypertension, CAD, heart failure thyrotoxicosis, sick sinus syndrome, and amyloidosis. Further, AF is common after certain procedures such as cardiac surgery with a perioperative incidence up to approximately 35%. AF is not a trivial rhythm because it increases morbidity and mortality, usually due to stroke.
There is a striking increase in the incidence of bradydysrhythmias and conduction abnormalities associated with progressive fibrosis in both the sinus node and atrioventricular conduction system in the elderly; sinoatrial pacemaker cells decrease progressively from 60 years of age such that approximately 10% of the cells are still present at age 75, while fat can also accumulate, serving to separate nodal tissue from the atria musculature.144 Bradydysrhythmias may be present preoperatively but can initially present as unexpected heart block under general anesthesia.145
Emphysema and chronic pulmonary obstructive disease are not associated with normal aging but are the consequences of exposure to environmental toxins, such as tobacco, which may vary among populations. One study from Norway estimated that in people older than 70 years, 11% reported having at least one current obstructive pulmonary disease, 8% reported daily wheezing, and 12% reported significant dyspnea.146 However, they noted that the only respiratory symptom or disorder to show any clear age-related pattern was dyspnea, which increased through 89 years of age before decreasing.
As noted, because of declines in immunologic function, the elderly person is more prone to pneumonia than a younger person. Furthermore, there may be an increased risk of aspiration pneumonia as a result of other conditions such as gastrointestinal sphincter malfunction or altered mental status.
As is expected in an aging population, the absolute number of patients with lung cancer is increasing. Historically, there has been a reluctance to treat elderly lung cancer patients aggressively because of a lack of supportive data and concern for potential toxicity. However, the bulk of evidence suggests that healthy elderly patients can benefit from therapy in all stages of non–small cell lung cancer and that the decision to offer therapy should be based on comorbidities and performance status rather than age.147
Although most gastroenterologic disorders that develop in younger people may also develop in the elderly, the presentation, treatment, and prognosis may be different.148 Disorders that may have a higher incidence in the elderly include peptic ulcer, ischemic complications of vascular abnormalities, drug-induced disorders, malignancies, and passive reflux. Competent upper and lower esophageal sphincters should not be assumed, leading to the increased risk of silent aspiration. Also important to consider in the perioperative patient is the high likelihood of a gastrointestinal side effect of a medication such as a nonsteroidal anti-inflammatory agent.149 Furthermore, there may be an increased risk of constipation and bowel obstruction with opioids in the elderly.
Known decreases in renal function and GFR lead to a high incidence of mild chronic renal insufficiency. Progression to chronic kidney disease is associated with a high risk of renal failure, cardiovascular disease, and death.150 Many common comorbid disease states contribute to the increased incidence of renal dysfunction, including systemic hypertension, systemic arteriosclerotic disease, and chronic CHF. Regardless of the cause, the severity of chronic kidney disease can be classified by GFR (Table 21-1). Albuminuria is also used for diagnosis of renal dysfunction. This is a common problem because 18% of people older than 60 years have albuminuria, and 7% have an estimated GFR less than 60 mL/min per 1.73 m2.151 In people 70 years or older, those percentages increase to 30% and 26%, respectively.151
Table 21-1 The Severity of Kidney Disease Classified by Glomerular Filtration Rate ||Download (.pdf)
Table 21-1 The Severity of Kidney Disease Classified by Glomerular Filtration Rate
|Stage||GFR mL/min per 1.73 m2|
|1||Normal or mild decrease|
The diagnosis of renal dysfunction is indirect as GFR is estimated from the serum creatinine concentration or with creatinine-based estimations. One should not rely on creatinine alone; equations for GFR estimation should incorporate additional demographic and clinical variables.
Other problems to consider include urinary tract obstruction, common in elderly patients with an increased rate of benign prostatic hypertrophy, urinary incontinence, and a high incidence of silent urinary tract infections that may lead to perioperative infections or even urosepsis if left untreated.
The known changes in the musculoskeletal system lead to predictable disorders, including tendon and ligament tears, especially in the rotator cuff, the biceps tendon, the quadriceps tendon insertion to the patella, the Achilles tendon, and the posterior tibial tendon. A large study in the United Kingdom identified the odds ratio of an Achilles tendon rupture to be 6.4% in patients ages 60 to 70 years and 20.4% in patients age 80 years or older.152 There is also an increased incidence of osteoarthritis with age. Less clearly associated with aging but with a high incidence in the elderly patient is rheumatoid arthritis.153 These conditions are associated with known problems with airway manipulation and positioning. Spinal column intervertebral disk degeneration with disk herniation and osteophyte formation is progressive in the elderly and may lead to cauda equina or nerve root impingement and symptoms of spinal stenosis. Other conditions include polymyalgia rheumatica, gout, and pseudogout.
Several endocrine disorders occur frequently in the elderly, including thyroid disorders, diabetes, and androgen deficiency.154 Glucose intolerance is especially important to assess, and thyroid disease is an underappreciated cause of morbidity in the elderly patient. A study of 3,233 individuals age 65 years or older showed an association between subclinical hyperthyroidism and development of atrial fibrillation.155 However, this study did not support the hypothesis that unrecognized subclinical hyperthyroidism or subclinical hypothyroidism is associated with other cardiovascular disorders or mortality.
Neurologic and Mental Status Disease
Starting with middle age, there is a progressive decrease in learning and memory, a factor to consider when assessing the ability of an elderly person to cooperate with perioperative care. An interesting hypothesis is that this is not caused by loss of the ability to generate new neurons but rather to a reduction in the decline of growth factors (fibroblast growth factor-2, insulin-like growth factor-1, and vascular endothelial growth factor) necessary for new neuron growth.156 There is also an increased occurrence of all forms of dementia, including Alzheimer dementia and neurologic disorders such as Parkinson disease.157
The risk of suffering a stroke increases linearly with age and is associated with other forms of cardiovascular disease, especially atrial fibrillation. For example, the proportion of strokes with AF in the United States is 6.2% for patients who are 50 to 59 years of age, 7.3% for patients 60 to 69 years of age, 16.5% for patients 70 to 79 years of age, and 30.8% for patients 80 to 89 years of age.158,159 Other causes of stroke are hypertension, cerebrovascular disease, myocardial infarction, structural heart disease, and cardiomyopathy. A history of neurologic dysfunction before a procedure may predict persistent increased cognitive dysfunction.160
Depression is very common in the elderly, with fewer reported symptoms than in younger people.161 It is estimated that more than a third of hospitalized elderly patients may suffer from depression.162 Not only does depression lead to increased symptoms from medical illness and increased use of health care resources, but it may affect the patient's ability to cooperate with preoperative conditioning and postoperative rehabilitative care. Interestingly, depression may be related to disturbances in other systems, such as the hypothalamic–pituitary–adrenal axis, cerebrovascular disease, inflammatory conditions, and nutrient deficiencies.163 Another condition to be aware of in the elderly is alcoholism, with implications for perioperative withdrawal and malnutrition.164
Visual impairment is common in elderly and aged patients. The most common causes include presbyopia, macular degeneration, cataract formation, diabetic retinopathy, and glaucoma. Untreated, visual impairment leads to physical handicap, increased incidence of falls, depression, social isolation, and dependency.165 Visual diseases and the medications used to treat them must be considered with the choice of anesthetic agents. Furthermore, perioperative disorientation or delirium may be in partly a result of declines in visual stimuli.
Hearing loss occurs linearly with age, but the variation in hearing thresholds is large. Possible explanations include precipitating medical conditions, coexisting diseases, prior environmental exposure (especially occupational), and undefined genetic contributions.166 Hearing impairment may also contribute to postoperative delirium.
Worldwide, the incidence of cancer in the elderly continues to rise with more than 50% of all cancers and approximately 70% of cancer deaths occurring in patients age 70 years and older in developed countries.167 However, the use of combined modality therapy may improve survival in a variety of malignancies in the elderly, despite the known risks of chemotherapy. Although the elderly are less well studied in clinical trials, age itself should not be used as a criterion for denial of cancer therapy. Rather patients should be carefully selected and evaluated for life expectancy, performance and nutritional status, social support, and presence of medical or social conditions that may impede therapy.168 Decisions should also be made with respect to the anticipated benefit in quality or quantity of life.