COMMENTARY

BP Targets in Patients With CAD: Is 140/90 Good Enough?

Henry R. Black, MD; Clive Rosendorff, MD, PhD, DScMed

Disclosures

August 03, 2015

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Henry R. Black, MD: Hi. I'm Dr Henry Black. I'm adjunct professor of medicine at the Langone New York University School of Medicine. I'm here today with my friend and colleague, Dr Clive Rosendorff. Clive?

Clive Rosendorff, MD, PhD, DScMed: Thank you, Henry. It's a pleasure being here. I am Clive Rosendorff. I'm a professor of medicine in the Division of Cardiology at the Mount Sinai School of Medicine, now called the Icahn School of Medicine at Mount Sinai. I also work at the James J. Peters Veterans Affairs (VA) Medical Center as a physician and director of graduate medical education.

AHA/ACC/ASH Scientific Statement

Dr Black: You've been in charge of a very important document about the treatment of hypertension in patients with coronary disease. Could you tell us a little bit about the genesis of that and what it covered?

Dr Rosendorff: In 2007, the American Heart Association asked a group of people to put together a statement that dealt with the management of hypertension in patients with coronary artery disease and also the prevention of coronary or cardiovascular events in patients with hypertension. It was felt that sufficient time had passed for the guidelines to be updated, and fortunately the sponsorship was widened to include not only the American Heart Association (AHA), but also the American College of Cardiology (ACC) and the American Society of Hypertension (ASH).

The structure of the report[1] that we produced was designed not only to provide some guidance to physicians about how they should manage hypertension in patients with coronary artery disease, but also to provide a sort of mini-review that would be an important educational tool. We included chapters on the epidemiology of hypertension and coronary artery disease, and on the pathophysiology or the mechanisms whereby there is a link between hypertension and coronary artery disease.

A very important section, which I can talk about a little more, is on blood pressure goals. Then we did separate sections on the different manifestations of coronary artery disease: first, established coronary artery disease with angina; second, acute coronary syndromes, which include unstable angina, non–ST-segment elevation myocardial infarction (MI) and ST-segment elevation MI; and third, ischemic heart failure. Our mandate from the three sponsoring organizations was that we should not particularly concern ourselves with primary prevention, because that is the subject of another very large group of people who are going to be issuing a separate report on that.

Dr Black: This is about people who are already have known cardiovascular disease.

Dr Rosendorff: This is the management of hypertensive patients with established and known coronary artery disease, yes.

Dr Black: Prior strokes as well, or is that a part of a different one?

Dr Rosendorff: No; the mandate was coronary artery disease only.

Blood Pressure: How Low Do We Go?

Dr Black: Okay. What did you focus on (or what did we focus on, because I was part of this)?

Dr Rosendorff: Besides the sort of general approach, which I've mentioned, it was felt that the most controversial area by far was the choice of appropriate blood pressure goals for these patients. There was a lot of debate and discussion about that, and I might say that however distinguished the people were who participated in this process, the recommendations are only as good as the evidence that is out there. The evidence for blood pressure goals in this sort of situation is quite weak, we have to admit that. A lot of it is based on what we thought was our mature judgment, and should be regarded as a guideline and not as a rigid rule to be followed without question.

If you think about it, I suppose that if you consider 140/90 mm Hg as being a cutoff for blood pressure control, it doesn't make any sense to say that somebody with a systolic blood pressure of 142 mm Hg is in grave danger of having a stroke tomorrow and somebody with a systolic blood pressure of 138 mm Hg will live forever. It is a graded risk factor. We know from the epidemiologic studies[2] that the lower the blood pressure in big populations, the better the outcomes of both MI and stroke. The real question was: How low should practitioners go in lowering blood pressure in patients with coronary artery disease?

Dr Black: Is this for diagnosis, or just for treatment?

Dr Rosendorff: We are talking about treatment. I think there's a consensus that patients with a blood pressure of less than 140/90 mm Hg should not necessarily receive antihypertensive medication, but could or should be treated like anybody else, with aggressive lifestyle modification—all the things we know are risk factors for the development or progression of coronary artery disease.

The real question is: Once they are on drug treatment, how aggressive should we be in lowering the blood pressure? Only one real study has addressed this directly, and that's the ACCORD[3] study.

The ACCORD Study

Dr Rosendorff: The ACCORD study, as you know, randomized patients into two groups: those with a standard blood pressure target of less than 140/90 mm Hg, and those with a more aggressive blood pressure target of less than 120/80 mm Hg. These were all patients with diabetes.

You would expect the vast majority of patients with diabetes to have coronary artery disease, whether manifest or subclinical. It was found that, in fact, there was no statistically significant difference in the outcomes for MI or hospitalization for heart failure, and a number of other variables that were measured.

Dr Black: But there was for stroke.

Dr Rosendorff: There was for stroke. I think the literature is fairly unanimous in saying that for stroke, the lower the better as far as blood pressure lowering is concerned.

Dr Black: That seems to be the thing that we all fear most.

Dr Rosendorff: Exactly. That's the most feared complication of hypertension, isn't it? So we looked at these data, and why then did we not say: You should lower the blood pressure to lower numbers than 140/90 mm Hg (which is the number we eventually came up with), such as 130/80 mm Hg or even 120/80 mm Hg, which was the target of the intensive group in ACCORD?

What gives one pause is the knowledge of the hemodynamics of the coronary circulation. The coronary, the myocardium, is perfused only during diastole. During systole the myocardium is contracted, the capillaries are constricted, there's virtually no flow. So the diastolic blood pressure is the perfusion pressure of the myocardium. If you go too low with the diastolic blood pressure, clearly the autoregulatory processes that would keep flow going will fail eventually when they reach the limit of autoregulation. And further decline of diastolic pressure will result in myocardial ischemia.

The problem is that we have absolutely no idea what that value is in normal coronaries, in coronaries with coronary artery disease, during tachycardia, during exercise—all of these are variables that might affect the lower limit of coronary autoregulation. We really have to make some intelligent guesses about what is reasonable and what is not reasonable, and I think that the committee came up with some fairly decent proposals; that is, they went with the general flow. And I must say there have been a whole lot of guidelines statements in the past 2 or 3 years—a tsunami of guidelines, I call it—and they all seem to be unanimous in looking critically at the evidence that 140/90 mm Hg is a reasonable target.

However, the wording we used was, "it may be appropriate" to lower it a little further even, to less than 130/80 mm Hg in patients with established coronary artery disease and certainly in those who are at risk for stroke, those who may have carotid artery disease, those who may have peripheral vascular disease, and possibly even in diabetic patients. We weren't as prescriptive as previous guidelines in saying that diabetics should be treated to a target of less than 130/80 mm Hg, and patients with chronic kidney disease (CKD) should be less than 130/80 mm Hg. We said that all of those may be appropriate, so it's a reasonable choice, a reasonable option, depending on the interaction of the physician and the patient, the condition of the patient, and how well a patient tolerates a lower blood pressure. Clearly, in the presence of coronary artery disease, the physician needs to be sensitive to the manifestations or worsening of myocardial ischemia with any slightly more aggressive blood pressure lowering.

Dr Black: This sounds very familiar, in that most of the recommendations in the last so-called Joint National Committee 8 (JNC 8) report were based largely on expert opinion,[4] despite an attempt to make it evidence-based.

Dr Rosendorff: We didn't discard the ACCORD data—I think that's important—which said that it didn't make much difference whether you lowered blood pressure to less than 140/90 mm Hg or less than 120/80 mm Hg. But we were cheered by the ACCORD data, which nobody talks about very much, in that the mean diastolic blood pressure in the intensive arm of ACCORD was around 64 mm Hg. Now that's quite low.

What I've just said about exceeding or going below the lower limit of coronary autoregulation can be dangerous; we know that a mean diastolic blood pressure of 64 mm Hg was not dangerous, because there wasn't an excess of MI and other complications. And 64 mm Hg was the mean; there must have been a spread around this, there must have been some very low values, and yet there was no excess MI or myocardial embarrassment, I might say.

Dr Black: What always struck me about the ACCORD data was that in the so-called standard group, they got to a systolic value of 133 mm Hg. If all doctors, without any guidance, could get to 133 mm Hg on average, I think we'd be doing a lot better than we currently do.

Dr Rosendorff: Then we wouldn't have to be debating this, because that's a very reasonable target.

Dr Black: That's fine, but it's not so easy to do it.

Dr Rosendorff: I know.

Pharmacologic Therapy

Dr Black: What about specific pharmacologic therapy? Was that dealt with?

Dr Rosendorff: Yes, it was. We looked very critically at what had happened in the intervening years, and quite honestly, nothing much happened in terms of new drugs or new insights into the utility of these drugs in this particular situation. In just about all grades of coronary artery disease, beta-blockers are probably center stage, no question about that. And because they are a very disparate class of drugs, it's important to choose the right beta-blockers, I think.

Dr Black: What about patients who have asthma? What do you do about them?

Dr Rosendorff: Asthma with a lot of bronchospasm is a good contraindication to the use of beta-blockers. And it's been found that some of the nondihydropyridine calcium-channel blockers (verapamil and diltiazem) are just as effective at reducing myocardial oxygen demand as beta-blockers are. The problem with those drugs is that you cannot use them if there's any left ventricular decompensation or heart failure, because they make that worse.

Addressing Heart Failure

Dr Black: You said we addressed heart failure; what did we say?

Dr Rosendorff: We're very lucky, in that all of the drugs that are being shown to improve outcomes in heart failure are antihypertensive drugs as well.

Dr Black: That's right.

Dr Rosendorff: We know that angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs)—any drug that blocks the renin/angiotensin system—have been shown to have outcome benefit in patients with heart failure; they are antihypertensive drugs. We know that beta-blockers, likewise.

Nitrates are used extensively in that situation, especially if there are symptoms, but nitrates have not been shown to improve outcomes in patients with hypertension and the utility in treating hypertension is, I think, a little bit uncertain. There have been drugs that block aldosterone—the mineralocorticoid inhibitors, such as spironolactone and eplerenone—which are very useful in difficult cases of hypertension and have been shown to have survival benefit in patients with heart failure. In general, there's a huge overlap between heart failure drugs and hypertension drugs, which makes our lives so much easier.

Dr Black: It makes it easier to write a document when you can do that.

Dr Rosendorff: Absolutely.

HFpEF Gray Zone

Dr Black: Is there anything else that you think was a real highlight of this—something different, or something that will catch people's attention?

Dr Rosendorff: We drew attention to the, I think, generally known fact that when it comes to heart failure with preserved ejection fraction, we are still struggling to find the appropriate therapies.

Dr Black: It seems to me that the best way to deal with it is to prevent it, not to have to treat it, because we're really not that successful at treating it.

Dr Rosendorff: Always. And the same is true for coronary artery disease, of course. We did emphasize lifestyle changes, but we didn't spend a lot of time or space on that, because that is going to be the subject of this really big AHA/ACC guideline statement that is in process.

Dr Black: That's going to be a very important thing. The problem, in my opinion, with that is that we already know that it's bad not to emphasize lifestyle changes, but we haven't figured out how to get people to follow a healthy lifestyle who are not committed to it. That's the hard part.

Dr Rosendorff: Exactly. Another really practical problem is we do have the tools—we have probably got all the drugs that we need to control 99% of patients with hypertension. But we haven't identified all patients with hypertension, and among those who do have hypertension, we haven't optimally controlled all of those patients.

Dr Black: It's too bad, because we know what to do.

Dr Rosendorff: Exactly.

Dr Black: It's how do we get it done that is the hard part.

Dr Rosendorff: Yes.

An Educational Opportunity

Dr Black: The statement is available in several journals. Should we all run to read it?

Dr Rosendorff: We tried very hard to make it easy reading but also an in-depth analysis, which could be regarded as an educational opportunity, as well as just giving some suggestions about how to manage a clinical situation. I think that it's well worthwhile reading.

It's published in four journals: Journal of the American College of Cardiology (JACC),[5] Circulation,[6] Hypertension,[1] and Journal of American Society of Hypertension (JASH).[7] I think that's unique among guidelines in having such a wide dissemination.

Dr Black: This is directed at physicians, but certainly I think, because I've participated in it and read it, that it's not too hard for people who are not physicians to appreciate it. And nontraditional providers—nurses, pharmacists—are very important people.

Dr Rosendorff: They would have no problem reading it, but it's not directed to the lay public as such.

Dr Black: Thank you very much for coming in and talking about this. I look forward to seeing whether people accept it as much as we enjoyed doing it. Thank you.

Dr Rosendorff: Thank you, Henry, and thank you for your enormous contribution to the development of this statement.

Dr Black: Thank you.

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