Friday, March 12, 2010

Mythbusters: Hypertension


It seems like there have been a lot of recent developments in the management of hypertension, and several sacred cows have become burgermeat. I thought I'd summarize a few of these important developments here:

1. Blood pressure targets in the over 80's
The Hypertension in the Very Elderly (HYVET) trial taught us that treating hypertension in the very elderly is effective in preventing stroke. However, we may have been over-treating the "oldest-olds" for years, and that target SBPs for this group should be< 150/80mmHg according to a recent Cochrane review. As nephrologists, we may have been particularly culpable, due inappropriate application of a 130/80 mmHg target for elderly patients with mild reductions in GFR ("CKD").

2. Who benefits from aldosterone blockade?
A strong association has been demonstrated between abdominal obesity, sleep apnea and aldosterone excess, such that it has been suggested that visceral fat may be a source of aldosterone, contributing to resistant hypertension in the abdominally obese. Recently, spironolactone has been shown to be effective in managing resistant hypertension in the abdominally obese, so keep it in mind.

3. The white-coat effect and BP variability
Reassuring patients who appear to only have spikes of hypertension when they come to see you in the clinic may be the wrong thing to do. This recent Lancet article suggests that variability in BP, and spikes of hypertension in particular, may in fact be more dangerous than sustained hypertension. An approach to managing this problem is to avoid agents known to increase BP variability, such as beta blockers. Furthermore, patients who believe that it's okay for their BP to be elevated because they have recently been active need to be educated that this is incorrect.

4. Allopurinol for hypertension
Urate is periodically in and out of vogue as an instigator / perpetuator of kidney disease and hypertension. I personally believe it to be a marker of oxidative stress, but am still undecided about it having a direct role in kidney disease and progression. I have treated severe hyperuricemia in CKD patients with this specific intention / hope of attenuating disease. This recent JAMA paper suggests this approach is not complete madness. This short-term crossover study of adolescents with hypertension and hyperuricemia found that allopurinol 200mg bid controlled hypertension on it's own in 66% of patients. Another one to keep in mind

That's enough for today, I'll return to this topic next time.

5 comments:

AK said...

Thanks,very good blog.Keep up the good work.

AK

Amar said...

great topic..
i have had bad experiences with aldactone in advanced CKD's..too much hyperkalemia and drop in GFR

Conall O' Seaghdha said...

Agreed - the adolecents in this study had essential hypertension only.

Dr. Simon E. Prince, FACP, FASN said...

Nice post..

I am a big fan of aldactone for HTN.. who is scared of a little hyperkalemia?!.. bring it on! Seriously, I use a good deal of Aldactazide (Aldactone / HCTZ combo) or Aldactone with low dose loop in pts with dec CrCl and do not typically have problems requiring withdrawal for HyperK

Keep up the good work

SP

Anonymous said...

Add in last year's Goicoechea (Spain) study on Allopurinol (50% reduction in hospitalizations, protection against GFR loss) and more recent studies showing improved endothelial function and even regression of LVH through urate lowering, yes indeed, "back in vogue" perhaps to stay.