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Omega-3 and Vitamin D; Vein Grafts and CABG: It's PodMed Double T!

— This week's topics include benefits of CABG, vein harvesting, new exercise guidelines, and omega-3 and vitamin D supplementation

MedpageToday

PodMed Double T is a weekly podcast from Texas Tech. In it, Elizabeth Tracey, 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 benefits of CABG, vein harvesting, new exercise guidelines, and omega-3 and vitamin D supplementation.

Program notes:

0:44 Two studies on vitamin D and omega 3 supplements

1:44 Excess risks not seen

2:44 Did not prevent cardiovascular disease or cancer

3:45 Industry sponsored study not released

4:01 FREEDOM follow on study

5:01 Followed almost 8 years and found lower mortality with bypass

5:40 Vein graft harvesting

6:40 Looked at endoscopic or open surgery

7:41 Need for venous grafts

8:17 Physical activity guidelines

9:17 Accrue over the day

10:01 Kids 3 to 5

11:01 End

Transcript:

Elizabeth Tracey: More tweaks to the exercise guidelines.

Rick Lange, MD: In diabetics with heart disease, are stents as good as bypass surgery?

Elizabeth: What about vitamin D and omega-3 or marine n-3 fatty acids with regard to a couple different health outcomes?

Rick: And when the surgeon takes veins for the bypass surgery, does it matter how he or she does it?

Elizabeth: That's what we're talking about this week on PodMed TT, your weekly look at the medical headlines from Texas Tech University Health Sciences Center in El Paso. I'm Elizabeth Tracey, a medical journalist at Johns Hopkins and this will be posted on November 16th, 2018.

Rick: And I'm Rick Lange, President of Texas Tech University Health Sciences Center of El Paso, where I'm also Dean of the Paul L. Foster School of Medicine.

Elizabeth: In a bow to the American Heart Association meeting, why don't we go first to the New England Journal of Medicine -- two studies that we're treating together that took a look at vitamin D supplementation and what they're calling marine n-3, but what I quipped, of course, as also known as omega-3 fatty acids and their preventative ability for not just cardiovascular events, but also for cancer.

In this study, they had almost 26,000 participants, including about a quarter who were black. They were randomized to receive these fatty acids with placebo, and when we treat the other study, also, the vitamin D supplementation. They had a median follow-up of 5.3 years, and they took a look at major cardiovascular events. And as we see all the time, of course, that number of 26,000 shrunk considerably to about 400 in each group. They also looked at other endpoints: the composite endpoint of cardiovascular events, MIs [myocardial infarctions], stroke, death from cardiovascular causes, and they also looked at excess risks of bleeding.

Basically, the upshot of the whole thing is, "Well, too bad -- it really didn't help." Same thing, unfortunately, with regard to the vitamin D supplementation. They were looking at cancer outcomes with regard to that. Once again, they took a look and found, "No, sorry, this really didn't help when it came to trying to reduce cancer incidence." The good news about the vitamin D, there was no risk of hypercalcemia and no other adverse events, but gosh, it just sounds like, "Why bother?" And I'm a little sad because we've been talking about vitamin D for a while. It's been our darling in the supplement world, and now it's like, "Eh, put that one on the shelf, too."

Rick: These were two primary prevention studies, so the only real entrance criteria was they randomized men over the age of 50 or women over the age of 55 to receive high-dose omega-3 fatty acids, that is one gram per day, or vitamin D, 2,000 units per day, and neither was effective in preventing cardiovascular disease or cancer. They even drilled down to specific types of cancer like breast cancer or prostate cancer or colorectal cancer. This dampens the enthusiasm for taking supplements, but it's really important information, because if they're not really beneficial, then we really shouldn't be recommending patients or individuals take them.

Elizabeth: And seems to me that this is really pretty much the final word. This is a big study, followed for an adequate amount of time. It's possible that following them for 10 years would have been more data-rich clearly than what they've reported in here. One question I have, though, is that remember that industry had reported a supplement that was a derivative of omega-3 fatty acids that they were supposed to report the data at the AHA. Did you hear anything about that one?

Rick: No, it's not been reported yet. Our listeners should rest assured is we don't report based upon reports or topics. We actually want to see the paper published that has undergone peer review, and we have a chance to get into the details of it as well. So if that's available, we'll report on it, but until then, nothing to report.

Elizabeth: I would say, until then, bag the omega-3s and the vitamin D supplements and turn instead to a good diet. Let's turn to one of yours. Which of them would you like to pick?

Rick: Let's talk about the FREEDOM Follow-On study. Let me set this. The original FREEDOM study looked at people that had diabetes and had blockages in two or more of their three blood vessels to the heart. And we know that those individuals, if they need to be revascularized or have their blood flow restored, can either have a stent placed, multiple stents, or have bypass surgery. The original FREEDOM study had 1,900 diabetics with multivessel disease, and they showed that those that had bypass surgery had a better overall composite outcome. They looked at mortality, stroke, heart attacks, and that was over a relatively small period of follow-up of about 3½ years.

What the Follow-On study does is it looks at it over 7½ years, and it uses what I'm considering the hardest endpoint -- that is, mortality -- to say, "Is there any benefit in diabetics with multivessel disease with bypass surgery compared to stenting?" What they found in the 900+ individuals they followed for almost 8 years was those that had the bypass surgery had a lower mortality. In fact, it was 24% in those that had stents and only 18% in those that had bypass surgery. Stenting had about a 36% increased mortality associated with it. This follows on the guidelines from the American Heart Association that if you're diabetic and have multivessel disease, you have a better outcome with bypass surgery than having multiple stents, even though these were some state-of-the-art, -- that is, drug-eluting -- stents in these patients.

Elizabeth: We should add that this was in the Journal of the American College of Cardiology. This is just such a beautiful segue that, of course, I have to break with tradition here and ask you to talk about your second one, which is in the New England Journal of Medicine. This taking a look at vein graft harvesting.

Rick: Elizabeth, you're right. Usually we alternate, but this just flows into, so when we talk about bypass surgery, there are two types of blood vessels that can be used. And so when someone has a blockage in the artery, a lot of times people think, "The surgeon goes in there and removes the blockage." You actually don't do that. You actually take another vessel and you bypass it. You go around it so the blood flow can go around the blockage.

That can be done with an artery in the middle of the chest called the internal thoracic or the internal mammary artery. There's one on each side. But a lot of the bypasses are done with veins that are taken from the leg, and there are two ways to do that. One is you have a long incision, and you open it up, and you take the vein out -- you harvest it that way and you use that as a bypass. The other is doing it endoscopically. You have to make small incisions, and you have to pull the vein out. And there's been some concern that that may injure the vein and make it less suitable, less durable over the long term.

So what this study did was it looked at 1,150 patients that were randomized in the VA system to undergo harvest either with the open surgery or with the endoscopic surgery. What they determined was that there was really no significant difference between the two different harvesting techniques with regard to the risk of adverse cardiac events: death, heart attack, or need to have another surgery. However, the endoscopic harvest was associated with about half the complications. There were about 50% fewer leg wound infections with that than there were the open surgery. This should give reassurance because the endoscopic harvesting has been available since about the mid-1990s, that that is just as good as the open surgery with less complications.

Elizabeth: Another thing from the AHA that we're not talking about and an issue that we have talked about on multiple occasions is that those arterial grafts are superior to venous grafts when it comes to long-term patency of the CABG. Why would somebody choose a venous graft?

Rick: Well, because that internal mammary artery and there's one on the left side and one on the right side of the chest. Typically, we use one of them. If they use both of them, it increases the risk of infections in the sternum. If someone has three or four or five blockages, that one artery isn't sufficient to address all of those blockages, so you have to supplement that with using veins in addition. So that's a very good question, Elizabeth.

Elizabeth: Okay. At least this gives people confidence going forward. Let's move away from the heart, then, and let's go to the Journal of the American Medical Association. The Department of Health and Human Services has said, "Hey, we've got these 2018 physical activity guidelines that we've just released." They took a look at all kinds of data out there in order to come up with their recommendations with regard to, "Hey, what do we need to do?"

Basically, we're still in the same place of adults should do at least 150 to 300 minutes a week of moderate-intensive or 75 to 150 minutes a week of vigorous-intensive aerobic physical activity. They also need, adults, some weightlifting in there, muscle strengthening on 2 or more days a week. They also take a look at subgroups: pregnant, postpartum women, and also children.

The upshot of this for me is that the overall guidelines haven't changed that much, but one thing they do advocate is that these little periods that we get up and move around, we really need to do that. If we have a desk job or sedentary kind of a job, we need to get up and integrate some kind of activity within our day and that that counts to the total of the amount of exercise that one needs to accrue during that time.

Rick: The reason why this is timely, because you say, "Everybody knows we ought to exercise," but when you look at the data, only about 26% of men, 19% of women, and 20% of adolescents actually meet these recommendations. That means the vast majority, 75% to 80% of individuals across all age groups aren't doing what's important. And we know, by the way, you can prevent about 32% of deaths by exercising. That is the excess mortality associated with not exercising to the recommendations.

The other thing that I thought was interesting, Elizabeth, is they dealt not only with the older individuals, but they even said, "Kids 3 to 5 need to be doing daily activity." That means we don't need to just address the adults. We need to do it in all age groups. Your point is well taken. When you go to the store, don't park at the closest parking lot. Park at the farthest one and walk a little distance. Don't take the elevator up one flight of stairs. Take the stairs. There are a lot of things that we can be doing to increase our activity. Why do you go through a drive-thru? Park, get out, walk in to eat your fast food, and then walk back to your car. So a lot of different things we should be doing.

Elizabeth: Right, and they all count toward that accrual of the ultimate total that you want to get to every day. As die-hard exercisers, of course, we ascribe to these notions.

Rick: Absolutely. We need to be doing things to make safe walking areas for adults and to increase youth participation in sports. It's not about winning first place. It's about participating in sports and making that a part of your daily routine.

Elizabeth: On that note, then, that's a look at this week's medical headlines from Texas Tech. I'm Elizabeth Tracey.

Rick: And I'm Rick Lange. Y'all listen up and make healthy choices.