The hypertension blood pressure threshold is 130/80 mm Hg, right? In this episode, Andrew Perry, MD, digs into the nuances with Eugene Yang, MD, of the University of Washington in Seattle, to discuss the update to hypertension guidelines published in 2017 by the American College of Cardiology and American Heart Association (ACC/AHA).
A transcript of the podcast follows:
Perry: Hey, everyone. Andrew here. My apologies for the delay in producing this episode. I moved a few months ago and I started a cardiology fellowship, and doing that has taken up a lot of my time and put me behind schedule on things that I want to do. I have a lot of ideas for new episodes and new material that I want to put forward, so I'm going to try to catch up by the end of the year. My apologies there.
Today, I have a really good discussion with Dr. Eugene Yang. He's a professor at the University of Washington and a cardiologist here. He helped review the guidelines for hypertension that were from the ACC and AHA. The major headline from those guidelines that came out in the news was how the target blood pressure changed from 140/90 to 130/80. When you look at the guidelines, it's actually a bit more nuanced than that, and there are specific patient populations who really should be treated with this with a goal of 130/80, whereas there are some others for whom maybe medication is not indicated for and a target of 140/90 may be acceptable. I talked with Dr. Eugene Yang about some of those nuances and those details there.
Perry: You were part of the committee to help write the guidelines for the ACC/AHA hypertension guidelines that were published in 2017.
Yang: Yes, so I was involved in reviewing the guidelines for the ACC and AHA in 2017. I'm also the chair of the Hypertension Working Group for the Cardiovascular Prevention Council for the ACC.
Perry: Perfect. I want to talk to you today about hypertension. I remember when those guidelines came out in 2017 when I was in the middle of my residency. Really, the takeaway from those guidelines and what people were talking about was the target had shifted. The goalpost moved from 140/90 to 130/80. As I dug into those guidelines more and read them more, I came to understand that that discussion is a bit more nuanced, and so I prepared a couple of cases to discuss that I think will highlight some of those nuances and we can discuss how those apply.
Yang: Sure.
Perry: First, we'll have Mrs. Jackson. She's a 42-year-old woman. She's African American. She has no active medical issues. Recently, she went to a company screening health fair and her blood pressure was noted to be 138/84. The health fair nurse told her she had stage 1 hypertension and said she should go see a doctor. She hasn't seen a doctor in years and she comes to your clinic. When you see her, the notable vital signs is that her BMI is 32, and on repeat measure, her blood pressure is 136/80. Of note, when you calculate her ASCVD [atherosclerotic] risk score, it's 2.3% at 10 years and 27% for a lifetime. For this patient, my first question for you is what's the preferred way or the best way to confirm the diagnosis of stage 1 hypertension?
Yang: I think there are a variety of recommendations on how to correctly diagnose it. Some of the tools that we have in the outpatient setting are to do home blood pressure measurements. A second way that's a little bit more complicated and a little bit more labor intensive is to do 24-hour ambulatory blood pressure monitoring where we provide the patient with a device to measure their blood pressure every 20 to 30 minutes over a 24-hour period and then record those measurements to make some decisions about whether the blood pressures are high enough to justify initiation of treatment. Then the third way is to have several office measurements that are consistently above specific thresholds, which we can talk about, that also can be used as a way to determine whether somebody needs initiation of blood pressure measurement. Typically, depending upon different sets of guidelines, you may either have two or three office-based measurements that are above specific thresholds that may indicate the patient has hypertension that would require pharmacological treatment.
Perry: What happens most for you in your clinical practice of those options?
Yang: I think we probably rely most on home blood pressure measurements because it is less expensive to purchase a new blood pressure machine such as one that I recommend and a manufacturer whose machines are used in clinical trials cost about $50. There are specific recommendations from the AHA/ACC guidelines on the proper technique, which I try to educate patients on by demonstrating to them the proper technique in the office, and then collecting that information usually over the span of 4 to 6 weeks and either having the patients send me the blood pressures through our electronic health portal or from the patients returning to the office to review the blood pressures is probably the most common way that I monitor the patients' blood pressures.
Then obviously, if they have repeated office visits, even prior to my own, that indicate elevated blood pressures, in some cases that can be another way to establish the diagnosis. But in most cases, I am more interested in collecting my own data because some of the pitfalls of office measurements are that they're not repeated a second time after they are initially elevated, and frequently patients' second blood pressure - when they're repeated in the office - may be substantially lower.
As an example, there was a study that came out of Metro West in Cleveland, Ohio. They did a study where the patients' blood pressures were above the 140/90 threshold, so they were given an alert in the electronic health record to repeat the blood pressure measurement. When they did that, the average systolic blood pressure was 8 mm [Hg] lower on the second measurement than the first measurement. That has a lot of clinical implications because if they just relied on the first measurement, then they might have been overtreated with medication, because a lot of times patients have this alerting response called "whitecoat hypertension" or "whitecoat effect" in those individuals who already have an underlying diagnosis of hypertension, and so we may be artificially or potentially overtreating those patients when they, in fact, don't have true hypertension.
Now when you're teaching them the proper technique, are these patients, are you giving them an automated blood pressure cuff or are you teaching them to do manual blood pressure cuffs?
Yang: Definitely not teaching them to do manual blood pressure measurements. In fact, in clinics, it is not recommended to do manual blood pressure measurements by your staff, such as your nurses and MAs, because of inconsistencies in accurately measuring them with manual recordings. In the office, even when they're collected by the staff, they do measurements with an automated cuff. Typically, what I do is I actually do repeat it myself manually to confirm their blood pressure readings, but in general, it's recommended to do readings using typically oscillometric devices. Typically, I will have patients purchase one of those devices, an automated arm cuff, and use that as a way to take reliable measurements at home.
Perry: I'm wondering if is just rolling over in his grave about the use of the oscillometric devices.
Yang: That's a more complicated question because these oscillometric devices definitely are not actually measuring the blood pressure, and so there are lots of complicated algorithms that are used with these devices to convert the signal that's generated in sort of a digital format into an actual pressure recording. There are definitely some challenges to the accuracy of some of these devices. But to receive international certification for the devices, the requirements are based on comparing the measurements recorded by these devices to manual sphygmomanometry recordings. If they don't maintain a recording that's within a certain threshold, then they're not certified. You can sort of rely on the fact that there are international certification standards that require the automated devices are within usually 7 or 8 millimeters of a manual reading.
Perry: I see. Now, let's get back to our case. You see her. Let's say you get her her home-based blood pressure monitoring. You confirm she, indeed, has stage 1 hypertension. Her blood pressure is pretty consistent to this 136/80 from what she had. The next question is should she be started on an antihypertensive medication?
Yang: I think this is a really good case that highlights some of the misunderstandings from the updated guidelines. The first thing is her ASCVD risk is less than 10%. When your ASCVD risk is less than 10%, the guidelines recognize this patient is not in a high-risk category where aggressive initiation of antihypertensive therapy is likely to be beneficial. Because her risk is so low, the threshold for initiation of treatment is still 140/90. Because her readings in the office are below that 140/90 threshold, the recommendation is to focus on lifestyle changes. As you pointed out, she's obese. Her BMI is 32. The first step is really to focus on lifestyle intervention, so working on weight reduction, exercise, reducing her salt intake. I sort of call it the "rule of 5." There are certain interventions that can result in up to 5-mm reduction of systolic blood pressure.
For example, losing 5 kilograms of weight or about 11 pounds can translate into up to a 5 mm reduction in systolic blood pressure. Reducing your sodium intake by 1,000 milligrams from your baseline intake can also help lower your systolic blood pressure by up to 5 points. Exercising 150 minutes a week of moderate intensity aerobic exercise can also have a potential effect of lowering your systolic blood pressure by up to 5 points. For a patient like this, the first intervention is lifestyle behavioral changes, and then giving the patient 3 to 6 months to start working on these interventions, and then also having her check blood pressures at home, as we talked about, to see whether there's any improvement with these specific interventions. In this case, the focus is not on pharmacologic therapy because her risk is less than 10%. The focus is on behavioral and lifestyle intervention.
Perry: I thought that was an interesting addition to the guidelines here is this incorporation of the pooled cohort equation, the ASCVD risk score. If I'm correct, I don't think that was discussed much over the prior guidelines, JNC 7.
Yang: 7 guidelines.
Perry: JNC 7 guidelines. Now, there's this additional focus on what is their risk and the patients who are high risk should be started on medication or those with low risk we focus more on lifestyle modifications.
Yang: Exactly. So her lifetime risk is elevated, right? It's 27%. Those things can be modified by making lifestyle changes, which would then affect her systolic blood pressure and probably improve her lipid profile, all of which would then impact her long-term risk of a cardiovascular event. That's why I think the focus in these low-risk patients is on sort of long-term strategies of how they can optimize their risk so that lifetime risk is significantly lower than where their starting point is.
Perry: Let's make a slight modification to the case. You've seen her. She hasn't seen a physician in a while. Let's say you check an A1C on her and it comes back at 6.9%. You start her on metformin. You recalculate her ASCVD risk score, and her 10-year risk is now 5.4%. Same thing. She still has stage 1 hypertension. We'll revisit this same question. Now knowing that she is a diabetic and this slightly more elevated 10-year ASCVD risk, should she now be started on an antihypertensive medication?
Yang: She now fits in a different category. In the updated guidelines from 2017, the 10-year ASCVD risk gets thrown out the window, so to speak, because she has a specific disease state where the long-term risk is considered much higher. As a result, the recommendation from the U.S. guidelines is that the target for treatment is really to get her blood pressure below 130/80 just because she has a diagnosis of diabetes. In her case, I think you could still argue she could focus on lifestyle intervention. It doesn't necessarily mean you have to immediately initiate antihypertensive therapy because she's got a BMI of 32. All the things we talked about previously can be applied here.
Now would the guidelines say, perhaps, you should be more aggressive and initiate treatment? Yes. But if you look at the case from a broader perspective, she's not that far off from being below that target of 130/80. This becomes a shared decision-making discussion that if we were to go strictly based on the guidelines, then the recommendation would be to initiate antihypertensive therapy. But I tend to give patients options because patients, most are reluctant to take medication, so I will typically give patients a window of 3 to 6 months to try to make lifestyle adjustments which might allow the blood pressure to come below that threshold where then she wouldn't necessarily need to be treated with medication. In this case, I think the correct answer would be that she should be treated, but that doesn't mean I wouldn't give the patient the option of trying lifestyle changes first to see if that would bring the blood pressure down into a target that's below that specific treatment threshold.
Perry: I think that makes a lot of sense. If we're playing by the book and by the guidelines, taking your board exam, probably this patient should be started on antihypertensive medication. However, in a real-life scenario, there is probably some time. Six months isn't going to make a big difference in this patient.
Yang: Correct.
Perry: If she's motivated and can make those lifestyle changes, lose some weight, say her diabetes becomes diet-controlled now at that point, it drops below 6.5. She manages to lose the 5 kilograms, like you said. Now her blood pressure is better, 130/75 sort of thing. Then we haven't started our medication. Whereas some of these antihypertensives, they get started and then you're kind of on it for life.
Yang: Exactly. I think that's what causes a lot of patients to be hesitant about treatment is, because when we have these discussions, frequently the question is, "Am I going to have to be on this forever?" Frequently, our answers are, "You are going to be on these medications for an indefinite period of time. Now if things change and your blood pressure has come down and you're getting very low readings, then there can certainly be some de-escalation of treatment, but that tends to be something we don't do as aggressively as we do with initiation of treatment."
Our de-escalation of treatment tends to be something we do less than actually starting medications and just keeping them on them without thinking about whether it makes sense to try to reduce their medication burden. That's why it is sort of a big deal, and since she's only 42, we're talking about potentially committing her to many decades of medication. In her case, I think if she were seeing me, I would try to focus on these lifestyle changes because she's young so that she doesn't need to start taking medications at such a young age.
Perry: Another thing you mentioned I want to just revisit a little bit is that her calculated ASCVD risk is minimally elevated, like 5.4%, but then there's this idea she has a specific disease. She has diabetes and that immediately puts her into a high-risk category, which I think is one of the fallbacks of the pooled cohort equation is that you put in diabetes. There's a spot to check there, but it does not automatically boost your patient's risk profile into that high-risk category for a patient like this.
Yang: Because she's young. I think that's why the clinical use of these guidelines can be confusing to, in particular, physicians or providers in primary care where they use the equation. They see that the score is not above a 10% threshold or whatever and then they don't then understand the patient has a comorbidity where the threshold or target is already defined irrespective of what that 10-year risk calculator indicates. Even for patients, it can be confusing. I think that's why for most people in clinical practice it is very hard to incorporate these guidelines because of all these little nuances about specific disease states where the recommendations are irrespective of what that 10-year risk is.
Another example for the lipid guidelines is you have a patient whose LDL is 192, where there's a suspicion that they have some sort of familial hypercholesterolemia, but if you plug in their 10-year risk, it might come back 1% because they're 38 years old or 42 years old. They use that still because they don't acknowledge or have not recognized a very high LDL is something you should just treat in most cases because it's a genetic disorder with significantly elevated risk of premature atherosclerosis.
Perry: Now getting back to our case. Let's say we give her 3 to 6 months to try to make some lifestyle changes and really there hasn't been a budge. A1C is still the same. She's still on metformin, and her weight has been the same, blood pressure hasn't changed. Now we're probably to the point where we would probably want to start some antihypertensive medication. What would be the preferred agent that you would start with? There's, I think, a lot of varying opinions that could go this way for this case.
Yang: I think this is an example of a lack of agreement on what treatment is necessarily the most appropriate for this patient. We have several factors to consider. One is she has diabetes. Some would argue that using an ACE inhibitor or angiotensin receptor blocker may be renal protective, and therefore that should be the first-line treatment for a diabetic patient. We don't know what her urine creatinine or urine protein levels look like, so some would argue that would be the first-line treatment. On the other hand, there are differences in ethnic sensitivities to different classes of medications. We know blacks tend to be more salt sensitive, and so they tend to respond better to calcium channel blockers and diuretics.
In the U.S. guidelines, there's no clear preference of classes of drugs whereas other guidelines do have specific class recommendations. In her case, I think if she were to see me, a lot of it is based on my own assessment of what their dietary habits are. Are they eating a lot of sodium in their diet where then maybe a diuretic might be more beneficial? But in her case, probably I would choose hydrochlorothiazide or chlorthalidone. Dihydropyridines cause lower-extremity edema. It's more common in women. It is a dose-dependent effect of the medication. The debate over hydrochlorothiazide and chlorthalidone is an interesting one. Chlorthalidone is clearly the treatment that was shown to be beneficial in many of the large clinical trials such as the ALLHAT trial, the SHEP trial, the Systolic Hypertension in Elderly People. Many of the large, randomized clinical trials that showed benefit to blood pressure lowering used chlorthalidone. In fact, there really aren't any large studies with hydrochlorothiazide. If you're a purist based on the clinical trial data, then chlorthalidone is the one that's been shown to be beneficial.
However, the reality is in clinical practice chlorthalidone's availability is definitely better, but it's not as cheap as hydrochlorothiazide, so the availability of the drug is definitely sometimes not quite as convenient. Secondly, the metabolic effects of chlorthalidone in terms of its impact on hypokalemia or hyponatremia or increasing glucose levels is definitely well known. One of the reasons why those in clinical practice probably have been hesitant to use it is because of these metabolic effects. In general, I think I tend to use hydrochlorothiazide more than chlorthalidone, because it's tolerated better from a metabolic standpoint and you can easily titrate the medication to high doses. Typically, I will max out the dosage of the medication at 50 milligrams a day, but then you start getting more issues with hypokalemia and hyponatremia, obviously, like you do with chlorthalidone.
Perry: Another question. With her history of diabetes and elevated ASCVD risk, should she be placed on a statin or would you do additional risk score modifications like a coronary calcium score?
Yang: That's a good question. Again, just like the hypertension guidelines, the lipid guidelines that came out last year really do not know... basically, the guidelines recommend anybody with diabetes who's between the age of 40 to 75 should be on at least moderate intensity statin therapy. They no longer incorporate a 10-year risk to make a decision about intensity of treatment. They basically just say, if you're 40 to 75 and you have diabetes, unless your LDL cholesterol level is below 70, then you should be taking a statin, at least moderate intensity.
Perry: You're giving atorvastatin 20 milligrams, basically.
Yang: You're going to get ideally 20 milligrams of atorvastatin, which would be moderate-intensity treatment. In the guidelines, the recommendation would be to start her on a moderate-intensity statin with the objective of achieving at least a 30% to 50% reduction in their LDL cholesterol from baseline. Where the calcium score becomes potentially beneficial is in a case where there is some reluctance of the patient to initiate treatment. When there is some clinical indecision, the guidelines now say if you're in, so in her case, she's at 5.4%. If you are in the borderline risk of 5% to 7.5% or you're in intermediate risk, which is defined as 7.5% to 19.9%, that's a situation where there's some indecision about initiation of treatment where calcium scoring can be beneficial.
Now one of the pitfalls, though, is the calcium scoring in terms of its prognostic value is less accurate in three specific populations. One is diabetic patients. Two is if you have a history of premature coronary artery disease or three if you actively smoke. In those three situations, a calcium score of 0 may not necessarily be a reassuring finding in terms of its prognostic value. Since she has diabetes, if she had a calcium score of 0, it still wouldn't necessarily tell us that we shouldn't be more aggressive. Where it's more useful is if it comes back 300 or 400, then the patients typically have greater willingness to initiate treatment. It becomes a harder conversation if the score is 0, but yet, we have to explain to patients it may not be accurate that your risk is still very low because of your underlying diabetes condition.
Perry: I follow. Very interesting. We could probably go off on a whole tangent about this, but we'll avoid that whole discussion, so good to know. Let's move to our second case. Mr. Anderson. He's a 68-year-old gentleman. He has a history of colon cancer, and he has status post a surgical resection about 2 years ago with neoadjuvant chemotherapy. He's currently in remission. He has hyperlipidemia and he's coming in. He has a blood pressure of 146/92, and ambulatory blood pressure monitoring confirms this diagnosis. His BMI is 26. Question: What should his goal blood pressure target be?
Yang: I think because he's 68 years old and he's a man, the likelihood his 10-year ASCVD risk is above 10% is pretty high. As a result, the blood pressure target for somebody with an ASCVD risk over 10% should be less than 130/80 for treatment, unlike the first case where the risk was less than 10% where a threshold for initiation of treatment was less than 140/90. His target should be less than 130/80 based on the fact that his 10-year ASCVD risk is undoubtedly going to be over that 10% threshold.
Perry: When we're considering about treatments for his hypertension, I think about this patient. He's got colon cancer. Currently, he's doing well. He's in remission, but should we be considering his life expectancy when we're talking about treatments for hypertension? Thinking about this is kind of a long-term risk reduction? Some of our patients maybe don't have a life expectancy of 10 years or more.
Yang: No, I think that is at least established in the guidelines. If you look at the guidelines for the elderly patients, which is defined as individuals over the age of 65, in the new guidelines the recommendation is a target blood pressure of less than 130/80. But they also have a second sort of bullet point in the guidelines that specifically talks about these issues about frailty. Are they independently living? Do they have dementia? What is their life expectancy? In that situation, the recommendation is the shared decision-making process to determine those factors. If this patient had severe dementia, I don't think anybody would argue what is the point of even aggressively treating blood pressure at all. In this case, he's 2 years out from remission. Part of it would be talking to the oncologist to get some perspective like what is his life expectancy based on his treatment and his current cancer status? That could help give you some insights into whether you should consider being very aggressive with his treatment strategy or not.
Again, the guidelines do give you the opportunity to consider these other factors to make those types of decisions about intensity of treatment and what those targets are. There's some new, interesting ideas about how to aggressively treat blood pressure. A paper came out earlier this year from a European group that suggested frailty is a way to assess aggressiveness of treatment. If somebody is very independently living and has no requirements for their ADLs [activities of daily living], then maybe more aggressive treatment makes sense. If you're in between where you do need some assistance with higher levels of your activities of daily living, then maybe you have sort of a shared decision about what your intensity of treatment threshold is for blood pressure. Then those who are very frail, who have no independent living ability, then that's a situation where you either have a very high threshold for treatment or you de-escalate treatment.
It's the first time that I have seen where you don't have a specific target just because of your age, but you consider these other variables to make decisions about what your blood pressure target should be based within the context of somebody's overall health status, which is like this patient. If this guy is active, plays golf every day, and has no physical limitation, once you establish his longevity is not significantly impacted by the colon cancer, then I would probably be more aggressive and try to treat his blood pressure below that target of 130/80.
Perry: His blood pressure is 146/92 and we're going to dive a little bit into some specific point here about whether he should be started on the medications he should be started on because there's a point in the guidelines where they recommend starting a person on two agents if they're above a target or if they are 20 mm Hg above their systolic target or 10 mm Hg above their diastolic target. He is 12 mm Hg above his diastolic target, and he's 16 mm Hg over his systolic target. Is this something where you would immediately jump to starting two agents on for this person?
Yang: This is, I think, a good example of individual choices about what to do. If you followed the guidelines to the T, then you might argue that using combination therapy would get this patient's diastolic blood pressure more likely to target easier because he's more than 10 mm Hg above that diastolic blood pressure threshold. But the other factors to consider are age. Even the SPRINT trial, which was a study of hypertensive patients in the United States, they loosened their requirements for initiation of combination therapy or even triple therapy of patients who are above 75, so they, in that case, recommended monotherapy initially because of concerns about potential side effects of aggressive intervention upfront.
This guy is not 75, but he's 68. His blood pressures are not really substantially above this 20/10 mm Hg. Even though it would be not unreasonable to do that, I tend to be a little bit more conservative. For this patient, I would probably start him on monotherapy, and then monitor his blood pressures over the course of a month to see what kind of response he has to treatment, and then titrate it up to try to achieve that less than 130/80 target. But would it be unreasonable to take the more aggressive stance? It's reasonable.
The rationale for using combination therapies upfront comes from many clinical trials that have looked at intensification of monotherapy in a stepwise fashion versus doing combination therapy upfront. Many studies have shown you are more likely to achieve blood pressure targets with initiation of low-dose combination therapy versus the stepwise monotherapy approach. That's the basis for why some of the guidelines recommend this. The European Society of Cardiology guidelines recommends single-pill combinations as a primary treatment for most patients, except older patients.
Perry: Interesting stuff. Last question. Last case. We have Miss Roberts. She's a 31-year-old woman and she has biopsy-proven lupus nephritis. Her GFR is 40 and she's currently stable on mycophenolate [Myfortic] for her lupus nephritis. What should her blood pressure goals be? Young patient, lupus nephritis, stage 3 CKD [chronic kidney disease].
Yang: This is an example of, again, I think a case where in the ACC/AHA guidelines they're pretty clear that if you have chronic kidney disease that the blood pressure target should be less than 130/80. In fact, essentially they apply that target to all patients regardless of age or their disease state -- with the exception of initiation of treatment for those who have a 10-year risk of less than 10%. In this case, at least based on the ACC/AHA guidelines, her target blood pressure should be less than 130/80. And even the European guidelines also recommend a target of less than 130/80, but there are differences of opinion in the diabetes guidelines, in the American Society of Nephrology guidelines. There's a lack of consistency among the guidelines, which I think is a cause for confusion for not only the patients, but for providers themselves, who are not sure about exactly what sort of guideline recommendations to follow. But if we were to use the cardiology guidelines, then the recommendation is the threshold for treatment should be less than 130/80.
Perry: I see. Interesting stuff. As kind of a wrap up, we've talked about a lot of different bits and pieces of the updated guidelines for 2017. I was a bit curious if you know any of the data on how we do on a national level of treating hypertension. How well are we at getting people to goal and has there been any updates since these guidelines were published on how we're doing on a national level of achieving this new target for those patients?
Yang: That's a great question. The positives are that over time we have been doing a better job of getting patients' blood pressure controlled, at least below the threshold of 140/90. Part of it is that it depends upon how you look at blood pressure control. If you look at patients who are treated for hypertension, the rates for patients who were treated to get it to a threshold of less than 140/90 was getting to the 60% to 70% range, but then if you just look at all hypertensive patients, even those untreated -- so not on any medications, that level was probably around 50%. The problem is that now that you have changed this target to a threshold of less than 130/80, the percentage of patients who would now have hypertension increased from 32% to 46% based on the updated guidelines. Now we have half the population who has high blood pressure, and then with this new threshold, for many of them the target is lower, so our control rates are certainly going to be less. The reviews indicate that the control rates are probably now 50% or 60% or 50% instead of 70% if you apply this new threshold and even lower if you look at all-comers, so irrespective of treatment.
That data takes time to accumulate. There hasn't been an updated survey of blood pressure, for example, from NHANES, so we don't know. I think one of the things I have heard from talking to some of those who were involved in making the guidelines from the NHLBI [National Heart, Lung, and Blood Institute] is, even if we don't have a lot of success in getting more people to less than 130/80, just the fact that there's heightened sensitivity to these new thresholds means that we'll probably get a lot more people hopefully to below 140/90. So at a population health level, that will have significant impact in terms of intermediate and long-term cardiovascular events if we can just get a higher proportion of people below that 140/90 threshold. I haven't seen any data that has looked at the impact of this in the last 2 years of how that's changed in terms of those thresholds. I'm sure there's small studies that have probably looked at this, but there's no population-level studies I have seen that has examined the impact of this at the national level.
Perry: My last question is I was just really struck about how the ASCVD risk score seems to be creeping its way into all these different guidelines. I was wondering about if you could comment on the data behind how that equation then got incorporated into these guidelines for hypertension.
Yang: Right, I think there's been some desire to have some common risk calculator to guide decision-making based on calculated risk, meaning that as I alluded to earlier, if your risk is on the lower side, less than 10%, then you're not in a high-risk category where maybe initiation of intense treatment is going to have a meaningful impact in terms of attenuating that risk over time. Similarly, the lipid guidelines, the intensity of treatment is based on risk. If you're 7.5% to 19.9%, the recommended reduction in your cholesterol is a little bit less aggressive than if you're in the high risk of over 20%. That's because if you look at the impact of the amount of cholesterol lowering, that has a direct impact on, let's say, 5- or 10-year risk of events. When you're in a lower-risk category, to achieve similar risk reduction does not require the same intensity of treatment. Does that make sense?
Perry: Yes.
Yang: The same thing applies to blood pressure. Again, if you're high risk, then aggressive intervention for blood pressure makes sense, but if your risk is low or lower, then the level of aggressiveness of treatment is also not going to have the same clinical impact in terms of modifying that risk if you're in a lower-risk category versus a high-risk category of above 10%. It's really to use that as a way to guide aggressiveness or intensity of treatment relative to your intermediate risk at 10 years.
Perry: We've had just an absolutely fascinating discussion about these topics, really getting into some of the nitty gritty of the guidelines. Do you have any last little pearls or tricks for helping other people navigate through these guidelines or resources that are available for internists, primary care physicians, residents, etc.?
Yang: Most of these guidelines, as you know, are available through the ACC.org website. They are downloadable apps that allow you to use your smartphone to calculate their risk based on their numbers. That's one easy thing to do, which I recommend. Some of the applications are less user friendly. For example, the statin intolerance app I find to be a little bit cumbersome, but the ASCVD Risk Estimator Plus that's available is not that difficult to use from your smartphone. Other things are now EHRs are incorporating these tools in the electronic health record. For example, we recently created a hypertension pathway that I was involved in creating for our institution. There are now smart texts you can use that will guide you through the guidelines about what pharmacotherapy to initiate, and then you can calculate their 10-year ASCVD risk within the electronic health record. There are ways of making it easier for people to use these guidelines and use that as a framework to decide on treatment and for risk estimation.
Perry: I like that. It's making the EMR a tool for us rather than as a tool for the MR. I like it.
Yang: You've got to start somewhere.
Perry: Once again, thanks for your time.
Yang: Thank you for allowing me to speak today.
Perry: To summarize a few of the key take-home points from this episode is the updated guidelines on hypertension in 2017 from the ACC/AHA target a blood pressure goal of 130/80 for those patients with elevated cardiovascular risk. That risk is evaluated by the Pooled Cohort Equation or the ASCVD risk score. Patients with diabetes or chronic kidney disease are automatically placed in this high-risk category and should have that target of 130/80. We discussed the use of lifestyle modifications in order to reduce blood pressure and how to incorporate someone's life expectancy into your clinical decision-making in your blood pressure targets. One of the apps that Dr. Yang alluded to that you can get on your phone is the ACC Clinical Guidelines app, and from there, you can access resources on the blood pressure guidelines and an ASCVD risk calculator. The app is available for both Android and Apple devices. I hope you enjoyed the episode. Thanks for listening.
, is a cardiology fellow at the University of Washington Medical Center in Seattle.