PodMed is a weekly podcast from Texas Tech. In it, Elizabeth, director of electronic media for Johns Hopkins Medicine, and Rick Lange, MD, president of the Texas Tech University Health Sciences Center in El Paso, look at the top medical stories of the week. A transcript of the podcast is below the summary.
This week's topics include herb/drug interactions, Afib and ablation in congestive heart failure, clot retrieval in stroke, and childhood kidney disease and adult end-stage renal disease.
Program notes:
0:39 Clot retrieval in stroke
1:36 Stopped early because expanded window worked
2:32 If brain tissue is dead it doesn't help
3:00 Herb/drug interactions
4:00 Ginkgo, St. John's wort
4:45 Sequelae of childhood kidney disease
5:45 Four times more likely to develop end stage renal disease
6:45 Look for compromised kidney function
7:22 Atrial fibrillation and congestive heart failure treatment
8:28 Much better than medical therapy
9:59 End
Transcript:
Elizabeth: How long can you do clot retrieval after someone has a stroke?
Rick Lange: Herb-drug interactions in patients.
Elizabeth: What happens when someone has had kidney disease as a child when they're an adult?
Rick: And in people with atrial fibrillation and heart failure, treating with a catheter ablation.
Elizabeth: That's what we're talking about this week on PodMed TT, the weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso, posted on February 9, 2018. I'm Elizabeth Tracey, a medical journalist at Johns Hopkins.
Rick: I'm Rick Lange, President of Texas Tech University Health Sciences Center in El Paso and dean of the Paul L. Foster School of Medicine.
Elizabeth: Rick, the International Stroke Conference has just concluded and we're featuring one study from that conference. This is the idea that you can sneak a little device inside somebody's blood vessel and retrieve the clot, and thereby reduce the sequelae that happened as a result of the stroke. Previously, it used to be a six-hour window. That was it. If you didn't get it in six hours, they weren't going to use it. Now they've expanded that to a 16-hour window.
What they did in the study that was published in the New England Journal of Medicine is they looked at 182 patients. They randomized them to either side, normal treatment or this expanded window for clot retrieval. At 90 days, 40% of the thrombectomy -- that's the procedure of retrieving the clot patients -- were functioning independently, while only 17% of the people who were treated per usual were. 14% of those with a thrombectomy died. 26% of those who were treated with usual treatment died. The study was stopped early, pretty powerful evidence that using this strategy to retrieve the clot is a good idea.
Rick: Now this in contradistinction to using medical therapy, that is called thrombolytic therapy where we give a drug to dissolve the clot. We know in that circumstance that if it's not administered in a timely fashion, within less than 6 hours, that, in fact, it's not effective. Now what I don't want our listeners to come away with is the idea that if they begin to have a stroke they can wait for hours to get to the hospital. That's not the case. The most important way to salvage brain tissue is to open up the artery to restore blood flow as quickly as possible with whatever means are available.
Elizabeth: I think one of the other things that was noteworthy about this study was they had to use an imaging study to make sure that the brain tissue that was surrounding the area of the stroke was still viable before thrombectomy was used.
Rick: What you're saying is if the brain tissue is already dead, removing the clot is not particularly helpful. That's also important. Now depending upon where an individual is, they may or may not have access to either of these therapies. That's why many of the societies are recommending acute stroke care centers that have expertise. If an individual gets to a hospital that doesn't have these therapies available, they get transferred as quickly as possible or even bypass an initial hospital to get to a stroke center.
Elizabeth: Let's turn now to the British Journal of Clinical Pharmacology one that spoke to you. This idea of herb-drug interactions.
Rick: I picked this particular one because there's not a whole lot in the literature that discusses herb-drug interactions or does it in a way that actually proves causality or gives an idea of how serious the side effects are. Many individuals take herbs and also medications to treat their medical conditions, and they don't make their healthcare provider aware that they're taking herbs, and they can directly affect the efficacy of the drug or even delay its metabolism so it increases the blood concentration of these medications. What these authors did was they combed the literature to look at herb-drug interactions, to look at causality, and to look at side effects and try to get an idea of what patients have been reporting in the literature.
What they discovered was these are, oftentimes, individuals with cardiovascular disease or neurologic disease, patients with cancer that are oftentimes taking herbs or supplements, and oftentimes people on blood thinners as well. There were a couple herbs that seemed to bubble up quite a bit. These are things like ginkgo biloba, St. John's Wort, Panax ginseng, and even green tea. Sometimes they increased the blood concentration, things like blood thinners, so people are prone to bleeding. Other times, they increased the metabolism of these drugs so they're less effective. People, for example, that have a liver or heart or kidney transplant and take one or more of these herbs, it may actually make their immunosuppressive agents less effective and cause rejection of the tissue.
Elizabeth: As we've mentioned many times in previous podcasts, there's also a substantial number of herbal supplements that don't have what they say they have. There's no oversight or regulation of them.
Rick: Which even makes it more difficult for the physician or the healthcare provider to know.
Elizabeth: Let's turn now to the New England Journal of Medicine. A study I served up as, "Gosh, what happens if you have kidney disease as a child?" Some of these studies, I think, are just so amazing, and this one in particular when I take a look at the data. 1.5 million Israeli adolescents, isn't that amazing that they can get all that? From 1967 to 1997, they took a look at those folks as they turned up for their compulsory military service, and then they linked those records to end-stage renal disease later on in life. They all had normal renal function and blood pressure when they were teenagers. Basically, they found end-stage renal disease in 2,490 persons, and those with childhood kidney disease were four times more likely to develop it.
Rick: These are kids that developed kidney disease. It could be either from some congenital issue, acute infection, some other unknown or autoimmune disease, and they got over it. Their kidney function looked like it turned to normal, and then over the course of the next 30 years, again, you just said they were four times more likely to develop end-stage renal disease. What that probably means is when we're born we have a certain number of nephrons. These are the filtering units in the kidney that filter the blood. If you lose some of those nephrons, the other remaining nephrons, they just increase their filtering capacity. That's fine for a period of time, but it's probably not well over the course of decades. This idea of having a little bit of reserve seems to be fine in the early years, but it predisposes them to later kidney disease.
Elizabeth: Nephron death is one possibility, and then a reduced number of those subsequent to that. Is there anything else that might predispose because you have something like pyelonephritis as a kid?
Rick: You might think, "Well, there's some underlying disease and that disease is manifested later," but they looked at three entirely different types of kidney disease. One is congenital. It usually has to be corrected with surgery. One is a pyelonephritis. That's an acute infection. The other is a glomerulonephritis, which is an inflammation. All three of them were equally associated with an increased risk of kidney disease later. Not only are they at an increased risk of developing kidney disease, but when they did develop it, they develop it at an earlier age than some of the recruits that never had kidney disease as a youngster.
Elizabeth: I guess the only thing that tells us is that we need to have a high index of suspicion in looking for compromised kidney function in folks who've had childhood kidney disease.
Rick: Yeah. Elizabeth, even though it's four times higher than the general population, it's still less than 1% of the kids that had kidney disease developed in their 40s as an adult. It's still relatively minor, but again, four times higher than the general population.
Elizabeth: Let's turn to your last one. That's this atrial fibrillation and congestive heart failure in the New England Journal of Medicine.
Rick: This atrial fibrillation, this irregular heart rhythm, oftentimes occurs in people that have heart failure. In this study of over 360 patients that had both, had heart failure and atrial fibrillation, half of which were treated with routine medical therapy, the other had an ablation. Those that had the ablation, at the end of 3 years, were more likely to be alive, they were less likely to be hospitalized, and they were less likely to die not only in general, but die of heart disease as well.
This is actually pretty astounding, because usually in the setting of atrial fibrillation, whether one uses medical therapy or a catheter ablation ... and the catheter ablation is where they insert a small tube through the blood vessels into the heart and place multiple small burns in the atrium to try to cause this irregular heart rhythm to return back to normal. It's an invasive procedure. But in people without heart failure, that procedure has been shown to be really no better than medical therapy in terms of overall survival or outcome. But in the patients with heart failure, it seemed to make a huge difference, much better than medical therapy.
Elizabeth: Since heart failure is a diagnosis that's increasing it seems to me really rapidly, it's probably a good idea that we can get our arms around this.
Rick: It is. In these individuals, it decreased their mortality by 50% and decreased the risk that they would be hospitalized by about 40% or 45%. I think this is a therapy in heart failure patients that could actually change their outcome, and it needs to be considered.
Elizabeth: I'm just going to ask you to comment in your clinical experience on ablation procedures. Sometimes they can be a little challenging. Sometimes they don't work right away. Was that true here as well?
Rick: Well, in fact, it recurred. The atrial fibrillation recurred in about 20% or 30% of individuals that have the atrial fibrillation. But when it recurred, it occurred less frequently. Over a one-month period, people were more likely to be in a regular rhythm than they were with medications. Even though it's not entirely effective, it still improved overall outcome and survival as well. I think this is a game-changer in terms of how we treat individuals with heart failure and atrial fibrillation.
Elizabeth: On that note, I'm going to talk about the clot retrieval this week on the blog. That's a look at this week's medical headlines from Texas Tech University Health Sciences Center in El Paso. I'm Elizabeth Tracey.
Rick: I'm Rick Lange. Y'all listen up and make healthy choices.
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