Advertisement

Advertisement

cerebrovascular system

The Aging Cardio- and Cerebrovascular Systems

The Aging Cardio- and Cerebrovascular Systems

Teaser: 

Barry Goldlist, MD, FRCPC, FACP

One of the prime tenets of geriatric medicine is the concept that the accumulation of multiple diseases and syndromes affect and contribute to functional impairment and make diagnosis and management of the elderly particularly challenging. Despite the value and accuracy of this construct, diseases of the vascular system and heart still remain the most important causes of morbidity and mortality in the aging population. If anything, current research has even indicated the importance of vascular factors in "non-vascular" diseases such as Alzheimer's disease. As well, cardiac status is often the limiting factor in how much therapy the elderly can tolerate for "non-vascular" conditions such as cancer surgery.

One of the more interesting areas in the confluence of vascular and non-vascular factors is that of Alzheimer's disease. Several genotypes for familial Alzheimer's disease with high penetrance exist, but the most common forms of Alzheimer's disease occurring in old age are likely the result of both genetic and acquired factors. Therapies to alter the basic pathophysiology of Alzheimer's are not yet clinically available, so the treatment of or prevention of other damaging processes is our best current strategy. There is persuasive evidence that when vascular disease and the Alzheimer's pathological phenotype co-exist, dementia is more likely. In a recent review in the Canadian Medical Association Journal, Feldman et al argue persuasively that at the present time, attention to vascular risk factors is the best way to decrease the burden of dementia in western societies.

Despite such arguments, there is ample evidence that this is not happening. With over 15 years of accumulated evidence from clinical trials, many elderly patients are still not being treated for their hypertension. Currently, a thiazide diuretic remains the treatment of choice for elderly hypertensives (inexpensive and effective), but the recent publication of the HOPE trial certainly suggests that choosing an ACE inhibitor is an attractive option for elderly hypertensives who are either with established vascular or at high risk for vascular disease.

Even more disturbing is the under-treatment of elderly patients with non-valvular atrial fibrillation. Most of the strokes in patients with atrial fibrillation have been shown to be embolic and thus preventable with anti-coagulant therapy. Why then are the elderly, those most likely to benefit from anticoagulation, the least likely to receive it? One reason is that clinicians often feel that the risks from anticoagulation increase with advanced age. This might be correct, but is nevertheless irrelevant. The real difficulty lies in balancing risk and benefit. Risk might increase with advanced age, but nowhere near as much as the potential for benefit (measured as number of strokes prevented). This means, if anything, we should be much more aggressive in anticoagulating older patients than younger patients. One often cited "contraindication" to anticoagulation is falls. A carefully performed decision analysis by Malcolm Hing and colleagues at the University of Ottawa, reported last year in the Archives of Internal Medicine, clearly shows that a history of falls should rarely, if ever, be a contraindication to anticoagulants. A more sensible approach would be to anticoagulate the patient and do a careful evaluation looking for reversible causes of falling. Unfortunately, a recent article in the British Medical Journal, has suggested that in routine practice aspirin is just as effective as Coumadin in preventing stroke. A careful reading of this paper, however, reveals that high-risk patients have been excluded from the analysis! In my opinion, high risk patients with atrial fibrillation (those over 75, those with congestive heart failure, hypertension or prior stroke) should be anticoagulated. The tendency of clinicians to aim for the lower end of the therapeutic range in elderly patients is incorrect in my opinion. Research has clearly shown that the amount of time spent at an INR below 2.0 increases the risk of stroke. Therefore, I feel that an INR of 2.5 is the appropriate target even for very elderly patients.

Treatment of acute myocardial infarction is another area where we have been slow to apply proven therapies to the elderly. Numerous articles attest to the under utilization of beta-blockers (and even aspirin!) in treatment of the elderly. It is not appropriate to withhold a therapy of proven value for relative contraindications (e.g. mild chronic obstructive pulmonary). My experience has been that most elderly patients can tolerate beta-blockers. The under utilization of thrombolytic therapy in the elderly is a more difficult issue. This is often caused by delayed or atypical presentation in the elderly, rather than a lack of knowledge or ageist attitude on the part of the physician. Nevertheless, the use of thrombolytics is more cost effective in older patients than younger patients because acute myocardial infarction is a more lethal disease in the elderly patient.

The most common indication for hospital admission to medical services for the elderly in North American is congestive heart failure. Research over recent years has shown improvements in both survival and quality of life (at least as measured by fewer hospital admissions) in congestive heart failure patients due to the use of ACE inhibitors, beta-blockers and spironolactone. At the present time, guidelines for how to apply all these modalities in the care of individual patients are still lacking, but should be forthcoming. Another proven modality for improving the outcome of congestive heart failure (as measured by hospital re-admission rates) is enhanced patient education and follow-up (usually by an advanced practice nurse). This type of program, however, is beyond the scope of an individual practitioner.

Finally, the belief that there is no point in optimizing cholesterol levels in the elderly is also proving false. Particularly in the setting of established coronary artery disease, the elderly benefit considerably from cholesterol reduction.

Much has been accomplished in the treatment of cardiovascular disease in the elderly, but much still remains to be done. In my opinion, the biggest "advance" is one of attitude. Study after study has shown that the absolute benefit from treating the elderly is generally greater than from treating younger patients. The advances that have primarily benefited middle-aged patients in the past are now successfully being offered to elderly patients.