Paul J. Hauptman, MD: Hello. I am Paul Hauptman, professor of internal medicine and director of the Heart Failure Program at Saint Louis University Hospital in St Louis, Missouri. Welcome to this program titled “Practical Tools for Sudden Cardiac Arrest Screening: Taking Ownership of Your Patient’s Risk.”

Joining me today are 2 colleagues: Michael Mirro, electrophysiologist and chief academic research officer at Parkview Health System in Fort Wayne, Indiana, and Kirk Garratt, associate director, Center for Heart and Vascular Health at Christiana Care Health System in Wilmington, Delaware.

The goals of the program are to review practical tools and screening protocols for sudden cardiac death (SCD) risk after percutaneous coronary intervention (PCI) and to discuss treatment strategy based on an individual patient’s risk. Today’s panel -- consisting of an interventional cardiologist, Dr Garratt; an electrophysiologist (EP), Dr Mirro; and myself, a heart failure cardiologist -- is an example of the interdisciplinary decision-making that takes place in clinical scenarios involving patients at high risk for SCD/arrest (SCD/A).

We will start by delineating the nature of the problem -- that is, the period of risk after primary PCI. Dr Garratt, while I know there is a risk calculator in development specifically for that population of patients, perhaps you can provide us with some context to start.

Kirk N. Garratt, MD: Recently, I was treating a 66-year-old man who came in fairly promptly after developing ST-segment elevation myocardial infarction (STEMI). It was a complicated PCI, but things ended well, and I told his wife that I thought he was going to do splendidly. However, 48 hours later, he had not recovered pump function the way I had expected. In fact, an echocardiogram quantified his left ventricular ejection fraction (LVEF) at 32%. He was having the occasional premature ventricular contraction (PVC) -- brief runs of 3 or 4 beats in a row -- but nothing too malignant.

I started him on the usual drugs -- angiotensin-converting enzyme inhibitor (ACEI), spironolactone, and carvedilol -- and was planning to discharge him. However, because he had PVCs, I decided to get an EP colleague to evaluate him and approve the discharge. When my colleague assessed the patient and his history, he said: “Well, you're doing all the right things. The problem is this man is at very high risk of sudden cardiac death.” This stopped me in my tracks. I really thought that, despite his recovery not being as immediate as I had expected, he would do well.

I had thought of this man as being a relatively low-risk individual, but, in fact, the data support the EP’s conclusion that this man was at risk.

When my colleague, Amir Halkin, analyzed the results of the CADILLAC trial,^[1] he found that solely having an ejection fraction of less than 40% is a significant risk factor and results in the patient being about two-thirds of the way to being high risk. If he or she has any other risk factor (ie, aged 65 years or older, poor blood flow, 3-vessel disease, renal insufficiency, anemia, or any other common comorbidity), the patient is placed in a high-risk category. As you know, “high risk” means a real risk of death in the next 1 to 2 months. For that reason, the EP recommended a wearable cardioversion device. That is the context for my enthusiasm in trying to heighten awareness on this issue.

Dr Hauptman: It is also fairly clear that this is a dynamic risk. So, presumably the patient whom you are describing is at high risk immediately after the procedure, and that risk decreases with time. In fact, we see this in 2 post-myocardial infarction (MI) studies -- one with valsartan^[3] and the other with eplerenone.^[4] It is not too momentous of an increase in risk -- it is clustered in the early post-MI period -- but, by extension, we can extrapolate about the post-PCI population.

Dr Mirro, a number of years ago, people might have said, “Well, maybe we should perform an electrophysiologic study on these patients.” Clearly, we do not do that routinely anymore. At what point would you apply a risk calculator -- if you use one -- in your clinical practice?

Dr Mirro: At our institution, we have taken the approach that this is a patient safety issue. We do use a risk calculator that Kirk alluded to, which is a risk calculator for SCD based on the CADILLAC data.^[3] This calculator takes into account LVEF as the variable with most weight in the risk calculation, receiving 4 points. The presence of renal failure is allotted 3 points, while age greater than 65, TIMI flow of 0 to 2, 3-vessel disease, and anemia all receive 2 points on the scale. “High risk” and “medium risk” are defined as having a score of 6 or more and of 3 to 5 points, respectively. These data have been validated by other studies, including the Cleveland Clinic Registry^[5] and the National Cardiovascular Data Registry (NCDR^®) CathPCI Registry.^[6] The practical approach that we use in our institution is to have LVEF alerts built into our electronic health record system, so that all clinicians who are testing the patient are prompted to make sure that a patient whose EF is less than 40% is receiving optimal medical therapy. We also have a nursing-led policy in place that mandates that high-risk patients are considered for or offered a wearable cardioverter before discharge.

Dr Hauptman: So, it is actually part of routine clinical care post PCI. Does that apply to the post-MI/post-coronary artery bypass grafting (CABG) patient as well?

Dr Mirro: Absolutely. Actually, the Heart Rhythm Society developed a no-cost downloadable mobile application called Sudden Cardiac Death (SCD) Protocol.^[7] We train all clinical staff on the indications, as well as the waiting period mandated by the Centers for Medicare and Medicaid Services (CMS)^[8] and applicable guidelines,^[9] for the implantable cardioverter-defibrillator (ICD). This is very helpful in ensuring that all clinical personnel who are interacting with the patient realize that they need to optimize medical therapy early. Patients who have low EF at time of discharge have sustained permanent risk and need an ICD after a 90-day waiting period.

Dr Hauptman: That policy was put into place precisely for the reasons that we are outlining -- namely, that the risk is dynamic. There is early risk, but it does tend to abate with aggressive medical therapy and, as you are suggesting, the patients can have some recovery of left ventricular (LV) function, which, according to their CADILLAC risk score, would also reduce their risk.

Dr Mirro: Yes. We have looked at wearable cardioverter-defibrillator use in our institution. In this patient population [Editor’s Note: post-MI/CABG], we found that EFs recovered in less than 90 days in 43% of patients, and they did not require an ICD implant. Another 40% ended up receiving an ICD implant, and the remaining patients did not received an ICD for a variety of reasons. Some patients were determined not to be appropriate for the ICD, because they had multiple comorbidities and a life expectancy of less than 1 year.

Dr Hauptman: It is prudent also to remind our colleagues that opting for a home defibrillator is not a viable option: we can say that based on the strength of a HAT.^[10] Dr. Mirro, I understand you were an investigator in that study.

Dr Mirro: Yes. The HAT Trial -- with Gus Bardy as the principal investigator -- was a very large National Institutes of Health (NIH)-sponsored international trial. Patients who had an anterior MI were randomized to cardiopulmonary resuscitation (CPR) training alone for the patient and family vs CPR training plus the home automated external defibrillator (AED). The results did not show a statistically significant benefit of having a home AED, because the majority of patients had sudden death in the middle of the night. Although they were living with someone (as per the inclusion criteria), AED use was actually quite poor because the individual had to wake up and use the device, which did not occur frequently. So, that strategy is flawed because we know that 80% of SCD occurs in the middle of night, usually in the early morning hours.^[11]

Dr Hauptman: Adherence is very important to beta-blocker effectiveness and the accompanying decrease in the risk of SCD. Beta-blockers may increase EF -- we now have some data on eplerenone in this setting^.[12-14] So, that helps mitigate against this risk of SCA, but if it were to occur, the patient would have to be very lucky to be close to not only the external defibrillator but also a bystander who is trained to use it. That is where the ICD has changed the entire field and provides patients with, essentially, a safety net.

Dr Garratt, can you discuss in more detail how the interventionalist looks at the risk of SCA/D? Are there risk factors during the PCI procedure itself that can help identify at-risk patients? Do you agree that it is mostly about the EF, or are there other anatomical features that would tell you that perhaps this is a patient who is at risk? Does the type of presentation -- ie, STEMI vs non-STEMI, or, possibly, the relative difficulty of stenting in a particular patient -- matter?

Dr Garratt: There is no doubt that the EF is the first milestone. As mentioned, if the LVEF is less than 40%, the patient is approaching the high-risk red zone; if it hits 30% or below, that is the high-risk red zone. In the NCDR CathPCI Registry, Bill Weintraub looked at risk of SCD/A patients with STEMI who had an EF of 30% or lower, who underwent an angioplasty procedure, and whose age was older than 65 -- a cohort that describes a large proportion of our STEMI population. Patients in this group had a 90-day mortality in excess of 30%. The most powerful risk factors in predicting mortality, in addition to LVEF, were age, multivessel disease -- which stands to reason, but it is an anatomic characteristic that we do not always think about in the STEMI treatment mode, because we are typically focused on the culprit vessel -- and, importantly, the renal insufficiency, which is a factor that influences mortality in a broad spectrum of cardiovascular disease.^[6] My concern is that I see my colleagues not showing awareness of this when assessing patients aged in the late 60s or early 70s who have mild renal insufficiency and multivessel disease but who have successfully undergone primary PCI. Clinicians may often look at these patients as low-risk individuals, and we need to change our mindset in that scenario.

Dr Hauptman: The really important point regarding the 90-day waiting period is conveying the message to the patient that after the waiting period they will not need the wearable defibrillator or an implantable defibrillator. Perhaps one of the most rewarding things I have a chance to do professionally as the heart failure physician is to turn to a patient and say, “It is time to take off your LifeVest and send it in. You do not need to wear it anymore; you do not need an implantable defibrillator anymore.”

Dr Mirro: Yes, this waiting period is critical to protect the patient, but educating all the members of the cardiovascular care team, both early in the post-PCI setting and in the new-onset heart failure setting, that while low EF is certainly the most predictive risk factor for high risk of SCD/A, there are other factors that should be taken into account before discharging the patient with optimal medical therapy.

Dr Hauptman: In de novo patients with heart failure -- for example, those with a nonischemic cardiomyopathy -- I like to examine the left ventricular dimensions. For the patient with dilated cardiomyopathy presenting with an end-diastolic dimension of 7 to 8 cm, while this may be a first presentation of cardiomyopathy, we can almost guarantee that it is not a new-onset cardiomyopathy. The waiting period can be very frustrating for those patients, especially if there is a family history of SCD or cardiomyopathy, where it is pretty certain that this is an established condition, yet we still mandate a waiting period. That is where we see most of the use of the wearable cardioverter-defibrillator in my program. It takes time to uptitrate medication and await response. We certainly do not conventionally look at the EF again until after 3 to 4 months, but it is during that period that we really consider the patient to be highly vulnerable.

To conclude our discussion today, we will review treatment strategies once a patient has been identified as high risk for SCD/A. Dr Garratt, as I understand it, you actually have a protocol for this at your institution. Do you formally recommend such a protocol to avoid missing patients who have this kind of risk?

Dr Garratt: Yes. At my former institute, Lenox Hill Hospital, and now at my current institute, we have a low threshold for bringing a consultant to the bedside to facilitate a multidisciplinary approach -- early initiation is key to the patient’s best outcome. In the STEMI setting, I believe it is a good idea to have the EP review the majority of patients who are about to be discharged, simply because the risk of SCD remains underappreciated by primary care teams, in my estimation.

Dr Hauptman: You are also raising another good point -- that our success in this area is also dependent on patients getting the follow-up that they need. It is pivotal that the patient receive the reinforcement about the importance of taking their prescribed medication and that we time the reassessment of LVEF appropriately. If we assess it 2 or 3 weeks later, that may not be the best interval. What we are finding, at least when we use the wearable defibrillator is that it is really a commitment of several months, followed by the reassessment of the LVEF. We then reach the fork in the road and make other decisions.

Dr Mirro: Education is the key to success. As Dr Garratt pointed out, his institution and ours are trying to implement protocols for managing high-risk patients, necessitating that all members of the cardiovascular care team are informed of the importance of optimizing medical therapy -- the administration of beta-blockers, ACE inhibitors, and aldosterone antagonists, as well as protecting patients with low LVEF, particularly the high-risk group, by using a risk calculator. This has been validated through the work of Dr Epstein, who published an analysis of outcomes in 8500 patients in the wearable cardioverter-defibrillator registry, which showed that most of the events occurred within the first month posthospitalization. The wearable defibrillator had a very high success rate with a low and appropriate shock rate of less than 1%.^[15] Again, education members of the care team on these data is key to protecting our patients from SCD.

Dr Hauptman: I do not think I can say it any better. With that, I'd like to thank Drs Mirro and Garratt for their participation today. Thank you to the audience. Please click on the “earn CME” credit link to take the CME post test and evaluation. Thank you for joining us.