Assessment of Geriatric Patients Undergoing Percutaneous Coronary Intervention
Can you tell us about your work in geriatric cardiology?
I am a general internist by training, but my research has focused on the intersection of geriatrics and cardiology. There is an emerging field of geriatric cardiology, inspired by the fact that our population of patients with cardiovascular diseases is aging. Among patients presenting with acute myocardial infarction (AMI), 30% are 75 years or older, and many of these patients have critical vulnerabilities in physical and cognitive function. Our group at Yale is just beginning a large, National Institutes of Health (NIH)-funded study to develop new risk models for older patients with acute myocardial infarction. It will incorporate geriatric assessments such as cognition, gait speed and frailty into risk models along with traditional cardiovascular factors.
This is the SILVER-AMI study. Can you share more about it?
It is an observational study of 3,000 patients age 75 years and older, who are hospitalized for acute myocardial infarction. The goal with SILVER-AMI is to develop risk stratification models specific to this vulnerable patient population. We know that traditional acute myocardial infarction (AMI) risk models do not function well in the older population. Our premise is that at least part of the reason is that the current risk models do not incorporate geriatric vulnerabilities such as frailty, gait speed, cognition and many of the other things that we know are critical to the way patients are able to recover from an acute event like MI.
When you say geriatric or elderly, is that always considered older than 65?
People have different cut points for what they mean by geriatric or elderly. For the SILVER-AMI study, we are using a population that is 75 and older. You have probably heard the saying that “60 is the new 50.” It used to be that 65 was a commonly accepted cut point for geriatric, but now it depends on what you are looking at. For the kind of study we are doing, where we are really interested in these critical vulnerabilities associated with aging, 75 and older is certainly a high-yield population. Of note, this group is also the fastest-growing segment of the MI population. So while there is no one cut point that is standard, it is increasingly at 70 or even 75. Another cut point that is commonly used is 85 and older, considered “oldest old.”
How is geriatric medicine developing?
It is a firmly established specialty in its own right, inspired by the aging-associated impairments that are not really focused on in other subspecialties of medicine, whether it be cardiology, nephrology, etc. Geriatricians are specially trained to focus on things like disability in activities of daily living, impairments in physical function, caregiver issues, cognition and dementia, all issues unique to the elderly. Geriatricians are also specially trained to consider issues of polypharmacy and how medications may interact differently in an older patient, given the physiologic changes that accompany aging, and also to consider the issues of treatment burden and competing risks. For example, giving a patient a medicine to treat their high cholesterol may have detrimental effects on the patient’s muscle strength and the ability to actually function on a day-to-day basis. Geriatricians are specifically trained to consider those kinds of complex issues. These are issues, frankly, for which we often do not have a robust evidence base, but we are starting to develop new studies in order to better understand them.
How could a geriatrician interact with interventional cardiologists on a practical, day-to-day level?
It would be great if we had enough geriatricians to work collaboratively with cardiologists in the care of older patients to assess any geriatric vulnerabilities, and discuss the risks and benefits of invasive procedures, medications and arrive at a comprehensive treatment plan. The unfortunate reality is that we have a shrinking supply of geriatricians in this country. On the positive side, there is an emerging appreciation that we need to equip our non-geriatricians with the skills to allow them to think like a geriatrician. This means getting information to cardiologists and other members of the cardiology team about the importance of things like frailty, so they can do these kinds of assessments and incorporate that information as part of their risk models. I think that is going to have to be the way we go in the future.
Can you define frailty?
From a conceptual standpoint, it is a physiologic state of increased vulnerability to stressors resulting from decreased physiologic reserve. The way I think about it in plain English is that frailty can be thought of as a state where you are more likely to have bad things happen to you, and when those bad things happen to you, you have a harder time recovering from them. A patient who is undergoing a catheterization may be more likely to develop a bleeding complication and will have a harder time recovering from that bleeding complication. From the practical standpoint of an operational definition, a few different definitions exist. Frailty is similar to heart failure and some other complex syndromes where there isn’t necessarily one strict definition. The most widely used definition for frailty has five criteria:
• Weight loss
• Low physical activity
• Weak grip strength
• Slow gait
It is tough to assess all five of those pieces, and cardiologists are already busy assessing and managing a number of different parameters. To make the measurement of frailty more practical, our group is advocating the use of a single measure, which is gait speed. Gait speed has been shown in many studies to hold the most prognostic information.
How do you measure gait speed when assessing patients?
It is remarkably simple. We measure out a course, usually 3-4 meters, typically 4 meters, but any number in that range is acceptable. It should be done in a hallway where the patient is able to walk that path in an unobstructed way. Ask the patient to walk at their usual pace and time it. There are a few different cut points that are used to indicate slow gait, but the most commonly used is <0.8 meters/second. If a patient’s gait speed is less than that, we consider it indicative of frailty.
Does something like dementia or impaired cognition interact with the concept of frailty?
The answer is complicated. I mentioned that there isn’t one standard definition of frailty. There are some frailty measures which incorporate cognition. There are other schools of thought that consider them to be two separate things, where frailty is very much a physical construct, and cognition is separate. I would say that the more traditional school of thought is that cognition is separate from frailty. However, I would say that certainly we know there is a strong connection between a patient’s physical abilities and their cognitive abilities, and often we see decline in those two areas together. Whether you want to conceive of them as distinct domains or one entity, they certainly have overlap, and one would interact with the other.
There have been reports of cognitive deficits measured after percutaneous coronary intervention.
That is right on and is part of the SILVER-AMI study. Often these kinds of cognitive deficits aren’t picked up on and may be subtle, and that speaks to the need for formal assessments of all these types of vulnerabilities. Particularly after an invasive procedure, which you could consider an insult, so to speak, in an older person, it can unmask a very mild degree of cognitive impairment, which perhaps the patient himself or herself wasn’t even aware of, or wasn’t apparent to those around the patient. If it is a complicated procedure, certainly that would place the patient at even higher risk, especially if they have a bleeding event, for example. Even the need for bed rest, sedative medications, all these things might be tolerated by a 50-year-old without a problem, but a 70- or an 80-year-old patients are just more vulnerable to bad things happening. That is really part of the whole concept of frailty. The more vulnerable you become, the less of an insult is required to throw you out of your homeostasis and lead to a decline in health status overall.
You mentioned that geriatricians also focus on the impact of medications. Any that might be relevant for cath lab patients?
Certainly, and the overall burden of how many medications a patient is on is an important issue. Any time a patient is on more than six standing medications per day, we call that polypharmacy, and we know that those patients are at risk for having adverse drug events. Certainly antiplatelet agents carry a higher risk of bleeding in older patients. We know that beta blockers can be problematic in patients who have falls and low blood pressure, and that statins can be associated with myopathy and changes in muscle strength in older patients, and they also contribute to falls.
What can interventionalists do today if they would like to adapt their pre and post procedure assessment specific to geriatric patients?
I am always careful to ask clinicians to add more to what they are already doing. But given where the evidence is now and what we know about older patients’ vulnerabilities, a timed, 4-meter walk and a brief cognitive assessment would make sense. There is a widely used tool supported by a number of neurologic associations and societies, called a MoCA, which stands for Montreal Cognitive Assessment. MoCA is a brief, one-page test and is freely available online at http://www.mocatest.org. It is simple and takes less than 5 minutes, and probably 5 minutes to score. An even briefer option, particularly for patients in whom clinicians suspect cognitive deficits, is to give the patient three items to remember, and then in five minutes, to come back and see how many items the patient can recall. That is combined with a clock-drawing test where you give someone a time, say 8:10, and the patient draws a numbered clock with hands to show that time. This combined test is called the Mini-Cog. Both the MOCA and the Mini-Cog are very brief cognitive assessments that can be used. These tests are an initial screening outside of a formal neuro-psychiatric environment that can help cardiologists and others gauge a patient’s vulnerabilities and how patients might fare after a procedure.
1. Singh M, Rihal CS, Lennon RJ, Spertus JA, Nair KS, Roger VL. Influence of frailty and health status on outcomes in patients with coronary disease undergoing percutaneous revascularization. Circ Cardiovasc Qual Outcomes 2011 Sep;4(5):496-502.
2. Chaudhry SI, Gill TM. Geriatric assessment to improve risk stratification in older patients undergoing coronary revascularization. Circ Cardiovasc Qual Outcomes 2011 Sep;4(5):491-492.