Percutaneous Coronary Intervention in the Elderly Patient (Part I of II)
- Volume 18 - Issue 6 - June, 2006
- Posted on: 8/1/08
- 0 Comments
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The elderly patient with coronary artery disease (CAD) poses unique challenges in clinical management. The basic problem is that there are insufficient data from dedicated clinical trials to provide a framework for decision making. Clinical decisions in elderly patients are thus mainly empiric. The proportion of elderly patients who are included in randomized revascularization trials is much lower than the actual percentage in the CAD population as a whole.1 Elderly patients in registries and large series exhibit the greatest benefit from interventional procedures when compared to patients in the general population, but they also run the highest risk of complications. Consequently, the younger age groups are preferentially revascularized in clinical practice, a paradoxical utilization of resources in a population that derive the least demonstrable benefit.2
Percutaneous coronary intervention (PCI) is less invasive than coronary artery bypass graft surgery (CABG) and requires a shorter recovery time. Such benefits would appear to be particularly advantageous in the elderly, especially those with coexisting noncardiac disorders that may pose significant additional operative risk. Conversely, the limited expected lifespans render conclusions concerning long-term benefits dependent on many extraneous factors besides treatment effect. Despite the fact that over 50% of all PCIs in the United States are performed in patients older than 65, the basic medical tenet to “first do no harm” leads to conflicting philosophical approaches. Further, since clinical trials of new therapies frequently exclude this age group, any conclusion about the efficacy of new techniques are inferential or based on observational data from registries and small series. Additionally, many randomized trials of PCI in various clinical settings have a bias in case selection, either specifically or indirectly excluding elderly patients. This bias may be particularly prominent in some studies that have a defined upper age limit for randomization, but may also be present due to exclusions when certain high-risk factors found in a high percentage of elderly patients are prespecified.
Physicians therefore must rely on clinical judgment to choose which elderly patients should undergo invasive procedures, and cannot depend on a complete evidence base to assist in reaching decisions. There are at least six different characteristics the physician should assess in reaching this decision: (1) mental status (i.e., dementia versus mentally active); (2) emotional status (i.e., the patient wants to live as long as possible versus a readiness to die); (3) independence (i.e., the patient lives alone versus being incompetent); (4) physical activity (i.e., immobile or bedridden versus a vigorous lifestyle); (5) compliance with medications; and (6) comprehension, by both patient and family, of the potential benefits and risks of a revascularization procedure.
The elderly are best considered as being comprised of several different subpopulations with differing therapeutic goals. Patients who are between the ages of 65 and 70 years can be considered the “young old”; that is, very active young retirees or individuals who are near the end of their working careers. These people travel widely and are relatively healthy. The second group includes those between the ages of 70 and 80 years; this group can be considered the “retired old.” These patients become increasingly less independent, but for the most part, enjoy their retirement. Finally, there are the octogenarians, or the “old old.” Many of these patients live in nursing homes or other assisted living arrangements. These distinctions are important because the expectations of people in each of these age categories in regard to their medical care differs both in terms of life expectancy and quality of life.
Further, the elderly have limited access to medical care in our society.3,4 This is evident in numerous ways: (1) they have limited access to transportation to bring them in a timely fashion to the doctor’s office or emergency room; (2) their insurance coverage is limited in many cases; and (3) the medical system generally is less aggressive in the treatment of frail, elderly patients.
Short- and Long-Term Outcomes after PCI
The contemporary in-hospital mortality rate of PCI is generally low in all age groups, but continues to be higher in patients over the age of 65. Age is powerfully associated with worse short-term prognosis and a greater rate of PCI-related complications.3–5 The expected in-hospital mortality rate is less than 0.5% for patients less than 65 years of age, but ranges from 2.2–4.0% for patients older than 75 years. The total complication rate for elderly patients is 9%, compared to 6% for that of younger patients. Postprocedural renal failure and bleeding are more common in elderly patients undergoing PCI than in younger patients.5,6
On the other hand, the overall long-term survival after successful PCI is good, even for the very elderly. Restenosis occurred in 15–30% of successful PCI cases prior to the arrival of drug-eluting stents and was not more common in the elderly. Excellent long-term relief of symptoms is achieved in most elderly patients who present with angina pectoris. However, patients over age 75 who undergo PCI appear to have a higher recurrence rate of symptoms than do younger patients, even with stent implantation.7 One possible reason for this higher rate of recurrence is that these patients are less likely to have complete revascularization than younger patients. Additionally, the more extensive disease likely represents more potential areas of progression and vulnerable plaques.8 Whether the use of drug-eluting stents has altered these long-standing observations has not yet been systematically evaluated, but no age-related differences up to age 65 have been identified. Drug-eluting stent trials have had < 20% of enrolled patients aged > 65 years, preventing a definitive subgroup analysis.24 The Rotterdam group9 has suggested the likelihood of a similar beneficial effect compared to bare metal stents based on one-year outcomes in 46 octogenarians. Data from the e-Cypher registry suggest that drug-eluting stents are probably as effective in the elderly population as in other age groups in preventing restenosis, but this has not been formally tested.19
Weintraub and colleagues10 constructed the generally accepted survival curves after balloon angioplasty based upon age. In every decile of age, survival over the course of the subsequent two- to ten-year period diminishes. This observation has subsequently been confirmed in numerous other registries, including Medicare11, the New York State Registry,12 and the Society of Cardiac Angiography and Intervention.13 The majority of studies assessing outcomes in elderly patients undergoing PCI in the balloon PTCA era reported less successful revascularization outcomes and more adverse events than in younger patients.5
Although coronary stents have improved clinical outcomes, registry data continue to demonstrate worse outcomes than in age-matched controls.6–9,14–16 Such observations have led some to question the value of aggressive PCI strategies in elderly patients.11,17 The relative survival rates of PCI versus CABG versus medical therapy in similar patient types from a single, large center or registry have not been definitively assessed in the contemporary stent era. Recently, a randomized trial of invasive versus medical therapy in the elderly found that patients older than 75 years of age benefit more from revascularization than from optimized medical therapy. Both symptom relief and quality of life were enhanced in patients undergoing PCI. However, this is a small trial with only six-month follow up.18
Conversely, Tu et al.20 evaluated the use of cardiac procedures and outcomes in elderly patients in the United States and in Canada. The authors found that U.S. patients were more likely than Canadian patients to undergo coronary angiography (34.9% versus 6.7%; p < .001) and PCI (11.7% versus 1.5%) during the first 30 days after myocardial infarction. Interestingly, the 30-day mortality rates were slightly, but significantly, lower for U.S. patients than for Canadian patients (21.4% versus 22.3%; p = 0.03). However, the one-year mortality rates were virtually identical (34.3% United States versus 34.4% Canada; p = 0.94).
The Alberta Provincial Project for Outcome Assessment and Coronary Heart Disease Study21 is a Canadian study demonstrating that elderly patients experience the largest absolute risk reductions associated with CABG or PCI compared to younger patients. Adjusted four-year survival rates in CABG and PCI patients were compared to medical therapy. The data demonstrated that the largest absolute risk reduction associated with revascularization was observed in the oldest patients. Additionally, the elderly also experienced the highest medical- and revascularization-associated mortality rates of any age group. These findings are important in illustrating the benefits of an aggressive revascularization strategy in elderly patients.
Seto et al.22 showed that quality of life improvements after PCI are not age-dependent. These authors evaluated the medical outcomes in a study using the Short Form Survey and Seattle Angina Questionnaire in a group of 295 patients over the age of 70 and 1,150 younger patients. At six months, physical health had improved in 51% of elderly patients, and mental health had improved in 29% of patients undergoing PCI. The authors found that the probability of clinically meaningful improvement in lifestyle following PCI was not significantly associated with age; elderly patients are just as likely to experience improved enjoyment in their life as younger patients after PCI. That post-PCI survival, but not quality of life, is age-dependent is a crucial observation, and is an important consideration in patient selection. Physical and mental health improvements are very important to the elderly. Especially as patients get older, it is reasonable that their goal may be to live better rather than longer.