Cardiology Digest podcast: Episode #25

Study #1

Today’s journey begins with a study examining the interplay between influenza and myocardial infarctions. Could the flu shot be more than just a seasonal precaution?  

"When it comes to patients with severe aortic stenosis who are referred for treatment, up to half of them have significant coronary artery disease. And until now, it was unclear how to best manage these patients when they get a transcatheter aortic valve replacement."

de Boer, AR, Riezebos-Brilman, A, van Hout, D, et al. 2024. Influenza infection and acute myocardial infarction. NEJM Evid. 7: EVIDoa2300361. (https://evidence.nejm.org/doi/10.1056/EVIDoa2300361)

Study #2

Next, we wade into a cath lab debate over fasting protocols. Join us to explore research that flips traditional pre-procedure fasting requirements on their head. Are we on the brink of a new era?

"Out of an abundance of well-intended caution, guidelines such as the 2017 American Society of Anesthesiologists guidelines call for fasting prior to elective procedures... But the lack of strong evidence to support this practice caused researchers to look into it further."

Ferreira, D, Hardy, J, Meere, W, et al. 2024. Fasting vs no fasting prior to catheterisation laboratory procedures: The SCOFF trial. Eur Heart J. Published online. (https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehae573/7742121)

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Study #3

Finally, we dig into the complexities of anticoagulation in transcatheter aortic valve replacement patients. This study sheds light on the choice between interrupting or continuing anticoagulation, and has implications for everyday practice.

"It’s pretty common for transcatheter aortic valve replacement patients to be taking oral anticoagulants… But we don’t have robust guidance on whether or not these patients should temporarily stop the anticoagulant for their transcatheter aortic valve replacement."

van Ginkel, DJ, Bor, WL, Aarts, HM, et al. 2024. Continuation versus interruption of oral anticoagulation during TAVI. N Engl J Med. Published online. (https://www.nejm.org/doi/10.1056/NEJMoa2407794)

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Please note that these timestamps are auto-generated and may be approximate.

Nora [00:00:06]:
Welcome to today’s episode of Medmastery’s Cardiology Digest! I'm your host, Nora, and in less than 15 minutes, I’ll get you up to speed on three recent cardiology papers that can impact your clinical practice. And be sure to stay tuned until the end of today’s episode, because I have a major announcement to share with you! Today’s first study is from NEJM Evidence, and explores the relationship between influenza and myocardial infarctions. Could flu shots be helping in more ways than we think? Next, we'll unravel new research to help us settle a cath lab debate on whether patients really need to fast before catheterization procedures. Then we wrap up with a New England Journal of Medicine paper that looks at the impact of continuing versus interrupting oral anticoagulation before transcatheter aortic valve replacement. Whether you're in the clinic or on the go, stick with us to keep your finger on the pulse of cardiology. 

Nora [00:00:58]:
Let's get started! The first study we’re going to talk about today noted a significant association between influenza infection and a subsequent risk of acute myocardial infarction, or MI. They also noticed something that may be counterintuitive at first, regarding exactly who is most at risk. This study, titled "Influenza Infection and Acute Myocardial Infarction", is an observational registry-based study conducted by de Boer and colleagues. It was published in the July 2024 edition of New England Journal of Medicine Evidence. This falls into a Level 4 category of evidence. (Level 1 is the highest level of evidence, and Level 5 is the lowest). Now granted, it’s in a lower level category of evidence, but an important thing to note is that its conclusions are compatible with results from previous trials. 

Nora [00:01:46]:
These researchers looked at the incidence of acute MIs during what they referred to as the "risk period", which was the seven days after testing PCR-positive for influenza. Then they compared those results with what they saw during the control period, which was within one year of the infection but excluded the risk period. 401 patients (with a median age of 74 years) had 406 MIs within a year of their influenza diagnosis. The risk of an MI was six times higher during the one-week risk period. Now for the part that I told you might be counterintuitive… Who do you think had the higher risk of MI? Patients with coronary artery disease? Or patients without? It turns out that patients who had no coronary artery disease had a relative incidence of just under 17. But it was only 1.4 for people who did have coronary artery disease. So, how can we explain this? Well, an expert commenting on the study reminds us of something you may already be thinking: perhaps the group with coronary artery disease was protected by the fact that they were more likely to be taking medications to lower their cardiovascular risk (for example, antithrombotics). 

Nora [00:02:56]:
And in fact, a post hoc analysis found that patients using antithrombotics did indeed have a lower relative incidence of MI—it was 4.1—compared to nonusers, who’s relative incidence of MI was more than three times higher. Because of this, the expert commenting on the study said providers of primary care should make sure their older patients know that flu vaccines might help to lower their risk of MI. Our next study found that abandoning the requirement for fasting before elective cath lab procedures led to fewer safety incidents and more satisfied patients. Out of an abundance of well-intended caution, guidelines such as the 2017 American Society of Anesthesiologists guidelines call for fasting prior to elective procedures (specifically, abstaining from solid food for six hours and clear liquids for two hours). But the lack of strong evidence to support this practice caused researchers to look into it further. Their paper is titled "Fasting vs no fasting prior to catheterisation laboratory procedures: The SCOFF trial." It was conducted by Ferreira and colleagues, and published in the European Heart Journal just last month. The study fits within a Level 2 category of evidence, which is only one step below our gold standard, Level 1.

Nora [00:04:07]:
This multicenter trial evaluated over 700 patients referred for either a cardiac implantable electronic device, coronary angiography, or percutaneous coronary intervention. They were randomized to either the standard fasting protocol, or no fasting. Their average age was 69 years, and 80% ultimately ended up undergoing a coronary procedure. The primary composite outcome included aspiration pneumonia, hyper- and hypo-glycaemia, and hypotension. Patient satisfaction was one of the secondary outcomes evaluated. Average fasting time in the no-fasting group was three hours for solid food and 2.4 hours for clear liquids. Average fasting time in the fasting group was 13 hours for solid foods and seven hours for clear liquids. So, were the fasting patients better off? Well, the primary outcome was observed in just 12% in the non-fasters versus 19% of the patients who fasted. 

Nora [00:05:00]:
A higher incidence of hypotension in the fasting group was the main cause of the difference. Clinical aspiration did not occur in any of the study participants. And patient satisfaction was significantly higher among the non-fasters. Ultimately the trial met the criteria for both noninferiority and superiority of the no-fasting protocol. An expert commenting on the study noted that complications tend to be rare in patients who didn’t have a chance to fast before an urgent procedure. So most cath lab operators probably won’t be surprised by the results of this paper. The expert said they still plan to continue to advise patients to fast before complex, higher-risk procedures. But they also stated that this paper provides evidence to support not requiring fasting for less complex, lower-risk procedures. 

Nora [00:05:55]:
Our next study found that patients who didn’t stop their anticoagulation therapy for their transcatheter aortic valve replacement ended up with increased rates of bleeding, and didn’t receive any benefits for stroke and other thromboembolic events. Now let's unpack the details of the study and what led up to it. It’s pretty common for transcatheter aortic valve replacement patients to be taking oral anticoagulants. In Western countries, for example, about a third of these patients are on them. Typical indications include atrial fibrillation, a history of pulmonary embolism, or the presence of a mechanical heart valve. 

Nora [00:07:01]:
But we don’t have robust guidance on whether or not these patients should temporarily stop the anticoagulant for their transcatheter aortic valve replacement. This new study attempts to shed light on how best to handle this. Titled "Continuation versus Interruption of Oral Anticoagulation During TAVI," it was led by van Ginkel and colleagues and published in the New England Journal of Medicine in August 2024 It provides Level 2 evidence on the issue (so it’s just one step below our highest level of evidence). The investigation was a randomized, international, open-label, noninferiority trial. Investigators studied almost 900 patients on long-term oral anticoagulants who were scheduled to undergo transcatheter aortic valve replacement. The patients averaged 81 years of age and about a third of them were female. 

Nora [00:07:46]:
A little over four out of five of them were on a direct oral anticoagulant. Patients were randomized into two groups: one continued oral anticoagulants through the procedure (the continuation group), and the other did not (the interruption group). Clinicians treating patients who stopped their oral anticoagulant told them when it was safe to start up again. The primary composite endpoint included cardiovascular death, major bleeding, major vascular complications, myocardial infarction, or stroke within 30 days of the transcatheter aortic valve replacement. And what did they find at the 30-day mark? When they compared the frequency of primary-outcome events between patients who continued anticoagulation therapy and those who interrupted it, interrupting anticoagulation therapy was not proven to be an inferior option. There was also no significant difference in rates of major bleeding or thromboembolic events. However, it’s important to note that clinically significant bleeding occurred more often in the continuation group—31%—versus only 21% of the interruption group. 

Nora [00:08:48]:
So, an expert commenting on the study said that based on these findings they’ll continue to advise patients to stop their oral anticoagulant prior to transcatheter aortic valve replacement, provided there isn’t a strong reason not to do so (for example, a patient with a recent pulmonary embolism). I want to start by thanking you for tuning in! We hope you enjoyed this episode, and got a lot out of it! If you have a few seconds to spare, please consider leaving us a review. They’re a huge help for people trying to figure out if they should give this episode—or any of our previous ones—a listen! New to Medmastery? Here’s some background! Medmastery has won multiple awards for our medical education programs, and is highly commended by the British Medical Association. We provide internationally accredited CME courses that are used by residency programs and universities around the world. We’re rated excellent by hundreds of users on Trustpilot, and more than one in five of our paying members reported that we’ve helped them save at least one life. 

Nora [00:09:50]:
We’d love for you to be next! Use the links in the episode description to go to Medmastery.com right now, where we’ve got a free trial account waiting for you! Before I wrap up today’s episode, I have some important news to share—it’s that big announcement I told you about earlier. This will be the final episode of Cardiology Digest. While it's bittersweet to say goodbye, we're incredibly grateful for the journey we've shared and the connection we've built with you, our dedicated listeners. We can’t thank you enough for being a part of our community! Want to stay in touch? Here’s the best way. 

Nora [00:10:23]:
Grab your free trial account on Medmastery.com—not only does  your account include our newsletter, Intelligent Thursday, which is packed with cutting edge medical insights to enhance your clinical practice, but you also get to sample our award-winning courses!  Until we meet again, here's to new beginnings! It’s been a pleasure to share this space with you, and I wish you a great week!