Proper Dosing of Anticoagulants in CAD/PAD - Episode 1
Overview of Coronary and Peripheral Artery Disease
Paul Dobesh, PharmD, and James Groce III, PharmD, define coronary and peripheral artery disease and consider typical symptoms and prevalence.
Paul Dobesh, PharmD: Hello, and welcome to this Pharmacy Times® Insights discussion, “Proper Dosing of Anticoagulants in CAD and PAD.” My name is Paul Dobesh. I’m a professor at the University of Nebraska Medical Center College of Pharmacy in Omaha, Nebraska. Joining me today in this virtual discussion is my good friend and colleague, Dr James Grose—most of us know him as Jay Grose. He’s a clinical pharmacy specialist at the Moses H. Cone Memorial Hospital. Today we’re going to discuss a number of topics pertaining to the proper treatment and dosing of anticoagulants in patients who have coronary artery disease [CAD], with or without peripheral artery disease [PAD]. So, let’s go ahead and get started on our first topic. Jay?
James Groce III, PharmD: OK. Thanks, Paul, for that kind introduction. I want to start by asking you a couple of questions.
Paul Dobesh, PharmD: Sure.
James Groce III, PharmD: Particularly, first and foremost, with this very broad subject that we’re discussing, how would you define coronary artery disease and peripheral artery disease, and what are the typical symptoms that patients might experience within these 2 diseases?
Paul Dobesh, PharmD: Yeah, it’s good to start out with this kind of basis. With patients with coronary artery disease or peripheral artery disease, what we really have to remember is, this is an atherosclerotic disease, and atherosclerosis is not discriminatory regarding which arterial bed it affects. Coronary artery disease is atherosclerotic disease that exists in your coronary arteries. Peripheral artery disease is atherosclerotic disease that exists in your peripheral, large vessels of your legs.
The typical symptoms—obviously, many of us are familiar with coronary artery disease in that usually it leads to chest pain or angina. Why this happens can be for different reasons. Patients can have fairly stable disease where plaques have grown—atherosclerotic plaques have grown—slowly over decades. And then when they exert themselves—maybe they walk for 20 minutes or they’re in the garden or doing laundry, whatever it may be—their myocardial oxygen demand outstrips the supply because of the atherosclerotic plaque and they get some chest pain. They rest; supply and demand come back into balance as pain goes away. Patients with coronary artery disease can also have acute plaque rupture, which leads to an acute coronary syndrome, which is much more of a medical emergency. These are patients who have chest pain. It usually happens at rest. Many times it wakes them up at night, and then they end up going to the hospital, many times getting a coronary intervention with stenting, or they may get medical management. But the presentation of coronary artery disease typically revolves around some type of chest pain related to a mismatch of supply and demand.
For peripheral artery disease, it’s actually not that different. It’s just the skeletal muscle instead of cardiac muscle. In peripheral artery disease, the most common presentation is what we call intermittent claudication, where patients will be walking, and so the demand in those skeletal muscles goes up, right? The legs are some of the largest muscles in the body. Demand goes up, and as they walk, basically, because of the atherosclerosis in those peripheral vessels of the legs, they get the pain. They stop and it goes away. They can have other types of symptoms for peripheral artery disease, too, but it’s all related to poor blood flow because of the atherosclerotic plaques. Sometimes men especially will lose the hair on their legs; there may be some discoloration and some blue tinting, loss of feeling, cool to the touch—all this is related to a poor blood flow situation. But, yeah, disease state, the coronary artery disease and peripheral artery disease, remembering that atherosclerosis is a systemic disease.
That question, Jay, to follow it back to you, would be, as we talk about coronary artery disease and peripheral artery disease, how common would you say these disease states are and how prevalent, and who has to be concerned about developing it, as well?
James Groce III, PharmD: Sure. That’s a great question, Paul, and I think 1 of the simple ways of addressing this is just to simply ask ourselves the question that you’ve asked, which is “Who is that within our practice?” I think regardless of our practice setting, we know patients that you’ve just identified, and I think there’s a tremendous prevalence of the disease, and I’m going to cite you some specific numbers. But, again, just keeping it pragmatic, we should just simply ask ourselves the rhetorical question “Who is not within our practice setting, defined as you just identified those patients?” Let’s put some real numbers to it versus just the rhetorical answer to the question. We know that more than 1 in 3 patients who are adults in the United States will have at least 1 type of vascular disease. I’m glad you emphasized that this often is a polyvascular disease, affecting so many vascular beds within the patient’s vascular system.
Certainly we know that 16.5 million adults in the United States have coronary heart disease, as you alluded to, as 1 of those subsets. Estimated annual incidence of having an MI [myocardial infarction] or a heart attack is about 580,000 new heart attacks and 210,000 recurrent heart attacks each year in the United States. As it relates to the potential for having a stroke in this patient population that has polyvascular disease, we know there are about 7.2 million adults living, having had a stroke, currently in the United States, and nearly 1 in 4 of these strokes that occur annually are recurrent strokes, with more than 4.6 million stroke survivors who are disabled—so, really, another patient population that we really need to focus on beyond the acute event versus the events and the components of the disease that keep on giving, I’m afraid.
Finally, the last one that you alluded to is peripheral artery disease. We know that in the United States, it affects about 8.5 million patients. For that patient population, within 5 years of their initial diagnosis, up to 80%…will have that leg pain that you described, the intermittent claudication, brought about by increased vascular demand when exercising or simply walking for so many of these patients.
Paul Dobesh, PharmD: Very good, yeah. I think it does bring up the fact that there is a large portion of this population that is affected by this disease state.