By: Dr. Geoffrey Modest
A new consensus scientific statement was released on the treatment of hypertension in patients with coronary artery disease (CAD) from the Am Heart Assn, Am Coll of Cardiol and Am Society of Hypertension, dealing with the appropriate hypertension target, whether there are benefits attributable to specific classes of anti-hypertensive meds, whether there are different efficacies of different meds in secondary prevention of CAD, and whether different types of meds should be used in patients with stable angina, acute coronary syndromes, or those with heart failure (HF) — see DOI: 10.1161/HYP.0000000000000018.
Background:
–Hypertension is prevalent: about 1/4 of US adult population (65 million people), and there is an increasing incidence with age (about 1/2 of those >65yo)
–Hypertension is bad for you: a major cardiovascular risk factor (increase of BP by 20/10 doubles the risk of fatal coronary event) and is the major risk factor for stroke (linear increase in risk, beginning at low levels of systolic and diastolic pressures, or SBP and DBP)
–Treatment works: lowering BP leads to rapid reductions in cardiovascular risk (10mm dec in SBP or 5 mm dec in DBP is associated with a 50-60% dec in risk of stroke death and 40-50% dec in CAD or other vascular deaths)
–Hypertension should be seen as part of CAD risk: there is a strong interaction between hypertension and the other cardiovascular risk factors, and the risk attributable to hypertension for CAD is much greater in people who have other additional risk factors (ie, we should not view hypertension as an isolated issue but as part of a complex interplay of risk factors, and we should be more aggressive in hypertension control in the presence of other risk factors)
–The document above is looking at hypertension control alone and by medications, but they do note (very appropriately) that the issues of lifestyle (diet, exercise, weight) as well as management of the other risk factors are very important
Prevention of CAD events in hypertensive patients with CAD
–Lowering BP is more important than using any particular drug, though some combinations are better than others: do not use ACE plus ARB; do use RAAS blockers with thiazides or with CCBs, combinations which have documented clinical benefit (ACE=ace-inhibitors, ARB=angiotensin receptor blocker, RAAS=renin-angiotensin-aldosterone system, CCB=calcium-channel blocker)
–A few comments about the individual agents:
–b-blockers are useful in setting of concommitant angina, those who had MI (though I should add, the data for benefit are only for the first 2-3 years post-MI), and those with HF (esp carvedilol, metoprolol, bisoprolol)
–ACE/ARBs: esp in those post-MI, or with HF, chr kidney disease (CKD), stroke, CAD (esp if high risk CAD).
–aldosterone antagonists: esp with HF
–CCB: alternative to b-blockers for those with angina, but may not prevent HF as well as ACE/ARB
BP goals in patients with CAD
–They note that there are considerable holes in the data on BP goal for people with CAD, so precise goals are hard to determine accurately
–There are significantly impaired hemodynamics in the setting of CAD. patients with normal coronaries can sustain lower DBP (myocardia perfusion happens during diastole) because of coronary artery autoregulation leading to increased blood flow; but, CAD impairs this autoregulation. as does LVH and microangiopathy. There are not a lot of human data on this, but the animal data suggests that we be very careful in lowering DBP too quickly or too much. studies mostly confirm that DBP in the 70-79 range are safe. This paper suggests “caution is advised in inducing decreases in DBP to <60 mm Hg”.
–At this point, <140/90 is considered a reasonable target for the secondary prevention of CAD events in those with htn and CAD
–A target of <130/80 may be appropriate in “some people” (not defined) with CAD, previous MI, stroke/TIA, other atherosclerotic disease
–In those with elevated DBP and CAD with evidence of myocardial ischemia, lower the BP slowly, trying to avoid DBP<60 if patient has diabetes or is >60 yo. One very common issue they comment on is that of people (esp older ones) who have stiff aortas, wide pulse pressures, and the imperative to lower the systolic to 150 may lead to a very low diastolic. Based on no direct data, they suggest a “reasonable BP target of <150/80” in those >80 yo. Those who do have DBP <60, should have careful assessment for signs/symptoms of myocardial ischemia. And these patients should be checked for orthostatic changes with standing, avoiding SBP<130, DBP<65 (they comment on this in their section on ischemic HF, but I think this is generally applicable)
HTN management in patients with CAD and stable angina
–First drug is b-blockers. can add CCB (or use this primarily in those not tolerant of b-blocker) and long-acting nitrate as needed to treat angina if symptoms persist on b-blockers. (avoid verapamil/diltiazem in combo with b-blocker because of increased nodal effects)
–Optimal overall treatment is b-blocker if prior history of MI; ACE/ARB if prior MI, LV systolic dysfunction, diabetes, CKD; and thiazide or thiazide-like diuretic.
–Target for patients with stable angina is same as in general patients with CAD, as above.
HTN management in patients with ischemic HF
–The usual management for those with reduced EF: thiazides (or loop diuretics if eGFR<30 or severe HF), ACE/ARB, b-blocker (carvedilol, metoprolol, pisoprolol or nebivolol), aldosterone antagonists. consider hydralazine/isosorbide in African-American patients and NYHA class III or IV HF. Avoid nondihydropyridine CCBs (verapamil, diltiazem), clonidine, hydralazine without a nitrate. also try to avoid NSAIDs
–For those with preserved EF: b-blockers, ACE,/ARB, or CCBs.
HTN management in the setting of ACS (acute coronary syndrome). I will not comment much on this (given my outpatient/primary care focus) other than to say that they reiterate the usual management, but comment that the target BP is <140/90 if patients are hemodynamically stable, though a discharge BP <130/80 is a reasonable option.
One issue not addressed in this document is that people with CAD or HF often need many of the agents above to treat their cardiac symptoms (angina, HF, etc) and their resulting blood pressure is often a lot lower than the 140/90 or even 130/80 target. they do not comment, but, more often than not, I find it necessary to lower the blood pressure significantly more than their target. But, I think it is important to go slowly, check for symptoms and signs of orthostasis, and be especially careful in hot weather (people can get dehydrated and more hypotensive), if there are reported falls, or if GI illness. One remarkable feature of the writing committee is that 15 of the 19 members had NO drug company affiliations…