#210 HTN in Dialysis: 5 Pearls Segment

Why can some people have twenty liters of fluid and yeah, they're short of breath, but they generally can tolerate it and the dialysis patients get into trouble so fast. And the answer is that steep part of a diastolic folic curve. The last thing we want to see is people's blood pressures 170s, 180s all night, because that person has a high risk of going into flash pulmonary edema and that's kind of a

That was doctor John Danzinger, a nephrologist at Beth Israel Deaconist Medical Center. Welcome to the Core I Am Thigh Pearls Podcast, bringing you high yield evidence based pearls. I'm Doctor Sherey Trivetti and I'm joined by

Hi, I'm Dr. Nathan Kudlipore, internal medicine resident at Bethesdrill Deaconess Medical Center. Today we're continuing themes from the last episode, digging specifically into nuances of blood pressure management and end stage kidney disease patients on hemodal.

Yes, I love this episode. I got so much out of thinking deeply about blood pressure and in all honesty, wish I had this teaching so many years ago.

I know, such an important topic, so let's delve into it. We'll start by running through the pearls.

As always, test yourself after each of the following pearls. Remember, the more you test yourself, the deeper your learning gains.

Pearl one blood pressure targets.

What numbers are we typically aiming for in patients on dialysis?

Pearl two timing medications and dialyzability.

Before a dialysis session, do you give blood pressure meds or not? And how does a medication's dialyzability affect when you give it?

And PERL III, Pharmacologic Management Nuances in Dialysis Patients.

Which blood pressure medications have good outcome data in patients with dialysis and which ones don't?

I think we've all been there imagining our patients waiting in a long line in the pharmacy, not really sure what their medications might cost or if it's in stock. Amazon Pharmacy was actually built to remove barriers for patients. On the clinician side, I love that you can see how much their medications are going to cost right away. And then on top of that, Amazon Pharmacy goes ahead and automatically applies any manufacture coupons or things, for example, from GoodRec.

But the reality is we're often meeting these patients at different points in the hospital or clinic and their blood pressures are all over the place. Nurses will be paging us about a blood pressure of one hundred seventy over ninety.

Yes, exactly. What do you do with that page and you're like, oh, do I act? Do I not act? And maybe the first thing to do is start with, what is the blood pressure we're actually targeting in patients who are on dialysis?

Okay, so even a step back to the numbers, there are two big categories of blood pressure readings to know about. The first is peridialetic blood pressure. These are the readings obtained right before, during, and right after dialysis in the dialysis unit. And then there's interdialytic blood pressure, everything in between sessions.

What we know from a lot of really good data is that it's the intra dialytic blood pressures. So the blood pressure between dialysis sessions that has the strongest association between, you know, blood pressure readings and cardiovascular mortality.

That's Doctor Erica Drury, a nephrologist at University of Rochester. So it sounds like it's the intradialetic blood pressures, the blood pressures between dialysis sessions that are more strongly associated with outcomes. So I guess what is our target then when we see this patient in on the floors in clinic in between dialysis sessions? What are we aiming for?

So unfortunately there's no consensus on specific blood pressure targets and dialysis patients. Some nephrologists use observational trial data in the diocese population, and some extrapolate from the general population data. So get ready for nuance.

Uh, womp womp. I was hoping it'd be an easy answer.

In general, we extrapolate from guidelines for the general population, so a target blood pressure of less than 130 over 80 is reasonable for most dialysis patients. And how should we obtain those blood pressures? So the gold standard as in the general population is ambulatory blood pressure monitoring.

Okay, so less than one thirty over eighty, that sounds very familiar, but I'm sensing a big but coming.

There is. And it's a big one. Because when you actually look at the outcome data in dialysis patients, there's a different range of blood pressure that's associated with the best outcome.

If you look at the relationship with the association of blood pressure to mortality, what the curve looks like. It's really interesting dialysis. So generally for you know, the general population worsened blood pressure, worsened outcomes, we're aggressive with blood pressure control. That is not true in So if you look, the data suggests that the lowest risk of the best outcomes are for those whose blood pressures are on the one forty to one fifty.

Ah. So patients with the lowest blood pressures have worse survival.

So we know that really low blood pressure can increase the risk of vascular thrombosis. So a patient who has a fistal lifer dialysis, hypotension can lead to thrombosis and so that's a poor outcome.

Yeah, you know, I can see someone who is well meaning trying to get the numbers to look good and may want to drive that blood pressure as low as possible. But if I'm understanding this correctly, we might be okay with a little bit of a higher blood pressure in patients with dialysis.

For those people who are off their dialysis cycles or who are a day or two behind and they're maybe above their dry weight, I would be very careful. Those are the group I would say, bring them down to one fifty. That's kind of a number I would think. One sixties is definitely getting too high. And you know, if they're well dialyzed and they've been in a hospital for weeks

All right. And then there's another nuance to throw on top of all of this, which is if we go back to the idea of autopsies in patients who are on dialysis, what we often find is these like quote unquote lead pipe vessels. Which begs the question, how accurate are these blood pressure cuffs in capturing these patients' blood pressure?

So one of our reviewers, Dr. Jeff William, pointed out that the blood pressure measured with a cuff relies on the distensibility of the blood vessel. So in these ESKD patients that have thickened, inflexible arteries, they're at baseline going to have higher systolic readings, making it impossible for us to truly know the pressure inside of those arteries. So even the way we're measuring blood pressure in this population is flawed.

Yeah, definitely. And then think about those low diastolic blood pressures we might see from those stiff arteries that can't recoil, right? So we probably shouldn't overtreat that increased pulse pressure that we might see.

Amazing. So let me try to recap. It's the interdialytic blood pressure, the blood pressures in between dialysis sessions that we should be focusing on when we consider bigger picture blood pressure control.

Great. And then the blood pressure targets in NC can use these patients is nuance, right? It's an area that we wish we had more consensus or trial data on. You might see some nephrologists extrapolate from general population data and aim for less than one thirty over eighty. But we do have some data, albeit it's mostly observational data, that may be a little bit higher systolic blood pressures of 140s or 150s.

Alright, now that we went over the targets that we're shooting for, or at least what we know about the targets that we could be shooting for, let's bring another nuance into the fold. Say our patient's already on blood pressure. When do we give it and how does that relate to the timing of their dialysis session?

While general medicine encourages us to really be aggressive with blood pressure control, in the dialysis patient, I would kind of walk back from that a little bit. because I'd rather see higher blood pressures and be able to dialyze them than not to be able to dialyze them at all.

So that's a great insight and a throwback to our primary goal here. The goal is fluid removal, and if we are compromising that with too aggressive blood pressure control, we're losing sight of the bigger picture.

Yes, definitely a fair point to think about if dialysis is happening or not. And I think the other thing is that I think we often get paged, you know, can we give this medication before dialysis? And I don't know about you, but I definitely didn't have a solid framework before this and I think unfortunately just made some gestalt decisions. Yeah, we can give this blood pressure med before dialysis or not.

First step is don't give blood pressure medications prior to that. Okay. Second step is to scale back blood pressure method. And frankly, you can scale back anything and everything. In my mind, there's no blood pressure medication that is indicated for any reason if it is interfering with fluid removal. So, you know, if they've had a heart attack and they're still on a beta blocker, I don't think that that's warranted if it's interfering with fluid removal because I can tell you that

I am so glad he said that out loud. And I guess the takeaway is if our patient's blood pressure is in a relatively good range. We do not have to give blood pressure meds before dialysis, with the exception, of course, if the patient's an AFib and needs a beta blocker or a calcium channel blocker for rate control. Yes, then give that one.

Another thing to think about in the inpatient setting is are these medications dialyzed and do I want them dialyzed or not? And that can help you understand, should you give them before dialysis or just wait until they're done with their session?

So dialyzability just means whether a drug gets removed during a hemodialysis session. The practical implication is simple. If you're giving a dialyzable medication before dialysis, a certain percentage of it gets washed out during the session. Non dialyzable drugs stay on board regardless of when the session happens.

Yeah.

Vencomycin is a great example. I think most internists will be familiar with how vencomycin gets dosed right after dialysis, and that's because venomycin is highly dialysis.

I love this point about, you know, meds being dializable or not. And I think since this episode I've definitely been a lot more thoughtful about, oh, is this medication dialyzable or not? And I think ran in even into a situation the other day where there was a patient who there was concern if they were pain seeking or not. And I realized, like, wait a minute.

Yeah, it definitely is, you know, a good thing to be thinking about in the back of your mind. So say your patient did take their blood pressure medication that morning, and it's a dialyzable medication. And those specific dialyzable medications we'll go over next. Technically, the recommendation is to supplement twenty-five to fifty percent of the initial dose after the dialysis session to account for what was removed.

Oh man, that is really useful to keep in the back of our mind. But we'll get into each drug class and if it's dialyzable or not in a second. But first let's summarize and maybe apply it to a a case. Say you have a patient, it's seven in the morning, their blood pressure is one sixty. Walk me through your thinking, Nathan. There's no right or wrong answers here.

Okay, step one is I'm asking myself, is dialysis happening soon, like in the next couple of hours? If yes, then I'd probably hold the blood pressure medication and let dialysis do the work so we can really focus on volume removal with dialysis.

Okay, fair, fair. But what if they're like persistently above one sixty, one seventy, and dialysis is maybe more than a few hours away?

In that case, I'd say it's reasonable to give anti hypertensives, probably would start with their home blood pressure medication, but think about whether the med is dialyzable and what time dialysis is actually scheduled for.

Yeah. Totally fair.

Okay, so if your patient is well dialyzed, say they're at their dry weight, they're doing their best that they can with salt reduction, but their blood pressure is still high. I think the question that I often ask myself is, are we reaching for the same first line blood pressure meds that we usually do for a regular hypertensive patient? Or are there different first line medications in patients who are on dialysis?

Dialysis patients are excluded from a lot of clinical trials. And so you should not just extrapolate data from a non dialysis population to the dialysis population and assume that you're gonna have the same outcome. For example, we know that ACE inhibitors and ARBs have cardiovascular benefit for many patients, but There have been some studies done, for example, with Foscinopril, an ACE inhibitor, and others with ARBs.

That again reminds me of that first episode. It's like so memorable the way Dr. Jan Zigger talked about the autopsy of these patients and how they had these lead pipe vessels and just appreciating that their physiology is different helps us think about All right, which blood pressure meds have seen good outcome evidence for and which blood pressure meds have we not seen as good outcome evidence for?

Let's start with beta blockers, which are first line in hemodialysis patients. And there is this study that compared attenolol to ACE inhibitor and showed that beta blockers had much better outcomes. We'll link more in the show notes, and I'll comment that these child use surrogate outcomes like left ventricular mass, but the takeaway is beta blockers do have outcome data behind them in the HD population.

Great. And then there's a dialyzability angle too, right? And interestingly, not all beta blockers behave the same during a dialysis session.

Metoprolol is dialysis. And if they need to be on their mitoprolol because it's improving their blood pressure or for cardiovascular benefit, if you give it before dialysis, you're just gonna dialyze it out and then they don't have that mitoprolol in their body. So that's another reason to hold that medication and give it after dialysis.

And the big reason to think about dialyzability here with beta blockers is of course with AFib and people who need rate control.

AFib can be challenging in dialysis. But you know, if they need their beta blocker, it's probably not a great idea to give them one right before dialysis that's just gonna get dialyzed out and then like long acting metoprolol and then it's gone for the day and they don't have it. So perhaps giving an after dialysis is the better thing for them.

Alternatively, a good pro tip is to switch to carvatolol or labatolol for rate control. Those ones are non-dialyzable, unlike metoprolol which is dialyzable. And if a patient goes into rapid ventricular response during the session itself, it's often triggered by aggressive fluid removal.

Yeah, and in that situation nephralgia can kind of give a small fluid bolus to slow things down. And if freight control isn't holding, then we can think about other things like rhythm control.

Next up bat, second line, calcium channel block. All of these are non-dialyzable, so no timing concerns.

That's a win.

Yes! An amlodipine in particular has randomized controlled trial data showing a meaningful reduction in cardiovascular events versus placebo in hemodialysis patients.

Nice, nice. So we can link that in the show notes for more details. But I guess the headline here is calcium channel blockers have demonstrated benefit in the end stage kidney disease population. Great, let's move on to RAS inhibitors. So ACE inhibitors, ARBs. I think this can often be a first instinct in just patients with hypertension without dialysis. But I think Dr. Drury flagged earlier on that might not be the case in northyalysis patients. So what does the data say?

So multiple trials phosidia with phosinopril, octopus with ulmasartin, Sarif with herbosartin all tested different RAS inhibiting agents and dialysis patients, and none of them demonstrated the cardiovascular benefit we'd expect from the general population data.

Generally we'll use ACEs because now they don't have any renal function. We don't worry about hyperkalemia as much. So ACEs ARBs are fine. Almost any medicine is fine. You don't have to worry about electrolyte instability anymore because dialysis is handling it.

Okay, so ACE, ABS, we don't have to worry about the potassium as much. If someone is, you know, going their typical dialysis session, it'll get taken care of with of course the the caveat that these meds still will increase the potassium in between those sessions. And then we should talk about the dialyzability of these RAS inhibitors. Let's start with ACE inhibitors. Unfortunately, most ACE inhibitors are dialyzable, except for fossinabroom.

But thankfully, ARBs are non-dialyzable across the board, so no timing concerns at all.

Ah, such a win for the ARBs there. So yeah, why don't we just put all these patients on ARBs instead of ACE inhibitors?

Yeah, so I'd say the bottom line is that if your patient needs a RAS inhibitor, just use ARBS. Use an ACE inhibitor only if cost is a genuine barrier. And if you do use an ACE inhibitor, phoscinipriel is the only ACE that won't get washed out during death.

I think that there's a lot about cardiac remodeling and so whether we should be more aggressive with MRAs and selective MRAs, I think probably co reasonable in trying to improve cardiac remodeling, but I think it's that I mean as you say, it's definitely a fine balance between over treating and under treating.

And that MRA comment is interesting. Medications like spironolactone, a plarinone, and the newer phenarinone will use those in heart failure for cardiac remodeling, but we have inconsistent results about their benefit in dialysis patients. I'll just say that they are ongoing randomized trial on MRAs and the evidence is evolving.

The one medicine I would say just be a little bit careful about is clonidine because clonidine side it's anticholinergic and makes people thirsty and it makes them drink. And so I use it sometimes but be careful because it can sometimes lead people to gain more and more weight. And so it's not a perfect drug in dialysis, but I still use it and I use the patch a lot'cause we have a lot of noncompliance and this way we can see if they're actually taking

So clonidine's anticholinergic effect drives thirst, which drives fluid intake, which drives volume overload. That's the exact cycle we're trying to break. It's not contraindicated, but be thoughtful. And the patch idea when inherence might be an issue, I must say, is quite clever.

Definitely, definitely. All right, so let's bring it home. Say we have that same patient who's hypertensive. We've done our best to optimize their dry weight. They're doing their best with their salt intake. What is the order of operations in terms of medications?

So beta blockers first, these have strong outcome data. Prioritize non-dialyzable agents like carvatolol or libatolol to avoid timing headaches and maintain consistent coverage. If you use metoprolol or athenolol, which are dialyzable, give them after dialysis. Or if they're on metoparol for AFib, consider giving it prior to dialysis and or increasing their dose by twenty five to fifty percent to account for how much is dialyzed out.

Yeah, great. And then second up we have the calcium channel blockers. Amblodopene has the best evidence and then calcium channel blockers, thankfully, are non-dialyzable, so we have no timing concerns there.

Third, RAS inhibitors are reasonable, especially if there's a comorbidity driving the choice. But don't rely on them for cardiovascular benefit the way you would in a non dialysis patient with hyper. Overall, we should have a preference for arbs, but if you use a NASE inhibitor, Fosinopril is the one that won't get washed out.

Right. And then I think threading through all of this, right, we're asking ourselves, is the medication dialyzable or not? That changes maybe when you might give it and if we might see the full effect of that medication by the end of the session and then whether we want to give a supplemental dose afterwards.

So we'll have a cheat sheet for the anti-hypertensives that get dialyzed out and the ones that don't in the infographic. But for me, I think it's easiest to remember that metoperol, probably the most common beta blocker we see, along with the tenalol, and then most ACE inhibitors that are getting dialyzed out, and then basically everything else does not.

Okay. I like that. That simplifies it. It's basically motoprolol and then most ACE inhibitors as well as a tenylol that's gonna get dialyzed out. I like that. Thanks, Nathan. That's very helpful. And that is a wrap for today's episode. If you found this episode helpful, our ask is to please share it with your team, your colleague, a future budding nephrologist like Nathan. I think

Thank you to Dr. John Danziger and Dr. Erica Drury for their time and expertise. Thank you to our reviewers, and as always, opinions expressed are our own and do not represent the opinions of any affiliate institutions. Take care.

Uh I'm I'm glad we made that change. I was like, this stuff wakes me up at nighttime. Like I hope somebody doesn't like take this as like the gospel. Mm-hmm. Yeah. Um sweeper.

Yeah.

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