Preventing Sudden Cardiac Death Following Percutaneous Revascularization

Case Report

A 68-year-old male with a known history of tobacco abuse, coronary artery disease, and previous myocardial infarction presented to the emergency room after experiencing chest pressure. He had multiple stents placed 10 years prior and additional stents placed three months prior to this admission. He had been experiencing symptoms for approximately three hours.

The patient was in moderate distress. Electrocardiogram revealed ST elevations in leads II, III, and aVF with ST depressions in leads V2 through V5 consistent with acute injury of the inferior and posterior walls of the left ventricle (Figure 1). The patient received aspirin, heparin, and a beta blocker. Given the patient’s additional history of contrast dye allergy, he also received intravenous hydrocortisone, Benadryl, and an H2 antagonist, and was taken to the cardiac catheterization laboratory emergently for angiography and percutaneous revascularization.

Cardiac catheterization revealed:

Right coronary artery (RCA): 100% mid-occlusion of the patient’s RCA; small, non-dominant vessel.

Left main: Normal.

Left anterior descending artery: Patent stents in the proximal and mid segments.

Left circumflex artery: 100% occlusion in the mid vessel within previously deployed stents, consistent with stent thrombosis (Figure 2A); dominant vessel.

Left ventricle: Posterobasal hypokinesis; ejection fraction (EF) of 30% to 35%.

The decision was made to intervene on the acutely occluded left circumflex artery. A guide wire was advanced into the left circumflex artery through the occlusion in the stents using the support of an over-the-wire balloon (Figure 2B). The balloon was advanced and several inflations were made within the stent. The balloon was then removed, and angiography revealed restoration of TIMI-2 to TIMI-3 flow throughout the stent, with visualization of significant residual stenosis and thrombus. A thrombus aspiration catheter was advanced into the occluded stent and two passes were made. The catheter was removed and a balloon was advanced into the stent and inflated several times. The balloon was removed and angiography revealed an excellent result, with TIMI-3 flow throughout the left circumflex artery (Figure 2C). The patient had resolution of ST elevation (Figure 3) and complete resolution of his chest discomfort.

The patient received a loading dose of prasugrel 60 mg orally (in place of clopidogrel, which he had been on until this hospital admission), and was transferred to the ICU. A two-dimensional echo revealed an ejection fraction of 30-35%. Due to his low ejection fraction, he was ordered a wearable cardioverter defibrillator (WCD), (LifeVest^®, Zoll) before discharge. The patient’s remaining hospital stay was unremarkable and he was discharged two days later.

Clinical Update

Upon returning home with friends, the patient let his pets out in the yard and went back into his house to feed them. At this point, the patient experienced an episode of ventricular tachycardia (VT) at a rate of 242 beats per minute; his WCD appropriately detected the episode and started broadcasting alarms. The patient fell unconscious and the WCD delivered a 150J biphasic treatment shock 58 seconds after detection (Figure 4). The patient’s friends drove him to the hospital.

The patient was hospitalized and received an implantable cardioverter defibrillator (ICD). The patient was discharged and continues to do well.

Discussion

This patient had known coronary artery disease and had a stent procedure of his left circumflex artery approximately three months earlier. He was doing very well after that procedure. In fact, he was preparing to ride his motorcycle in an organized charity ride when he started to experience chest discomfort. He called his daughter who transported him to the emergency room where he was transferred emergently to the cardiac catheterization lab. The patient underwent an intervention resulting in successful recanalization of his stent. After the procedure, the patient was treated as a clopidogrel non-responder and started on prasugrel.

This patient’s post-PCI EF was 30-35% and the decision was made to first optimize medical therapy with the goal of improving left ventricular function. It is known that the risk of sudden cardiac death (SCD) is increased in patients with an ejection fraction less than 35-40%.¹ To provide protection from SCD while medical therapy was titrated, a WCD was prescribed. On the day of his discharge, the patient experienced a life-threatening arrhythmia that was appropriately treated by the WCD.

Post-MI patients with low ejection fractions are known to have significant risk of SCD in the early period following PCI.^2-4 The EF threshold for increased SCD risk is known to be to 35-40%. Managing this risk requires consideration of many factors, including consideration of ICD waiting criteria (40 days post-MI and 90 days post-revascularization), optimizing medical therapies, and ensuring patients who would benefit from an ICD return for evaluation and implantation. The dramatic, day-of-discharge, life-saving therapy delivered by the WCD in this case demonstrates the risk of SCD that post-PCI patients with low EFs face in the first three months following their cardiac event. This case also demonstrates the importance of proper SCD risk screening and, where risk is determined to be present, acting to ensure the patient is appropriately protected from SCD until their long-term arrhythmic risk can be determined.

Dr. Goodfellow can be contacted at rgoodfellow17@yahoo.com.

Disclosure: Dr. Goodfellow reports no conflicts of interest regarding the content herein.

References

1. Buxton AE, Lee KL, Fisher JD, Josephson ME, Prystowsky EN, Hafley G. A randomized study of the prevention of sudden death in patients with coronary artery disease. Multicenter Unsustained Tachycardia Trial Investigators. N Engl J Med 1999;341:1882-1890.
2. Toda K, Mackenzie K, Mehra MR, DiCorte CJ, et al. Revascularization in severe ventricular dysfunction (15% < OR = LVEF < OR = 30%): a comparison of bypass grafting and percutaneous intervention. Ann Thorac Surg 2002 Dec; 74(6): 2082-2087; discussion 2087. 
3. Halkin A, Singh M, Nikolsky E, Grines CL, et al. Prediction of mortality after primary percutaneous coronary intervention for acute myocardial infarction: the CADILLAC risk score. J Am Coll Cardiol 2005 May 3;45(9):1397-405.
4. Stone GW, Rao SV, Hermiller JB, Kadish A. Prevention of sudden cardiac arrest post PTCA in high-risk patients. Medscape Education Cardiology. Available online at https://www.medscape.org/viewarticle/741503. Accessed May 15, 2012.

BEHIND THE CASE

Real-World Use of the ZOLL LifeVest: A Wearable Cardioverter Defibrillator

Cath Lab Digest talks with Ross J. Goodfellow, DO, FACC, FSCAI, Health First Cardiovascular Specialists, Merritt Island, Florida.

Tell us about your practice.

I am an interventional cardiologist in a multi-specialty group with five cardiologists and over a hundred physicians. We are owned by Health First, which operates four not-for-profit hospitals. The hospital where the case took place was at Cape Canaveral Hospital in Cocoa Beach, Florida, which has two cath labs.

How did you determine the patient featured in your case study was at high risk for sudden cardiac death?

This gentleman was someone who had known coronary artery disease and was found to have a fair amount of left ventricular dysfunction following the procedure. Typically, if someone comes in with an acute myocardial infarction (MI), they wind up getting some assessment of their left ventricular function, if not during the catheterization itself, then certainly by echocardiogram. This is one way to assess risk for sudden cardiac death, and certainly the gentleman in question was having a fair amount of ventricular ectopy while he was hospitalized after the event, which made him particularly high risk.

What are some of the challenges in managing patients at high risk for sudden cardiac death?

Management is always a challenge in someone who has had recurrent coronary intervention. There are always compliance issues — emphasizing to the patient that they need to be very diligent about taking their medications as prescribed. Other challenges would include trying to keep them out of the hospital for not only anginal chest pain, but also congestive heart failure and other kinds of cardiac issues. Arrhythmias are, of course, a concern. Many of these people have co-morbidities such as diabetes and kidney disease, which make it challenging because we have to coordinate with other specialists on the patient’s medical regimen.

Describe your experience with the LifeVest.

I first became familiar with the LifeVest through one of my colleagues who is in electrophysiology, and through in-servicing by the company representatives. At first I wasn’t quite sure whether it would actually work, but the LifeVest has delivered life-saving therapy to my patients, both to ischemic cardiomyopathy patients like the one I describe in the case study, and to non-ischemic cardiomyopathy patients. It is effective. The nice thing is that the LifeVest can record arrhythmias and function like a Holter monitor, so we can learn whether the patient is having other, less-than-life-threatening arrhythmias, such as atrial fibrillation. There are not many things out there in medicine that clearly make a difference in terms of life-saving therapy. Defibrillators in general, including the LifeVest, certainly do make a difference in saving lives.

How has it changed your patient management?

There is no question that for people who have an MI and even a borderline moderate to severe cardiac dysfunction post-op, the LifeVest is something that needs to be considered fairly routinely, because there are not too many things we can do. Intervention in acute MI is something that saves lives and certainly defibrillation from a potentially fatal ventricular arrhythmia does as well, and I have seen it happen to a few of my patients. It is impressive. The LifeVest is something I consider in all of my patients who have substantial MIs. I am not saying every single person who has an MI should get it, but certainly every cardiologist should consider the LifeVest for patients who have had large MIs with the potential for a great deal of scarring or who are having ventricular arrhythmias post-MI.

When you present it to the patient, what is their reaction?

We explain that it is for their protection, and a temporary fit, anywhere between 40 and 90 days. It is a little cumbersome, particularly since we are down in Florida, and not something you want to wear to the beach, but that is a mild sacrifice to make, given the life-saving benefits.

You noted in your case that the shock was given 58 seconds after the arrhythmia was detected.

The patient made it to the hospital without any neurologic issue. He was conscious and cognizant. He got a permanent defibrillator and is back living his life.

If a LifeVest was not available, what would typically be done to help these patients?

The restrictions put in place by Medicare and insurance companies do not allow us to put in permanent implantable defibrillators until a waiting period has occurred, in order to see if left ventricular function improves after revascularization. If the LifeVest was not available and assuming the patient was not having any active arrhythmias, he would have been discharged home without a permanent implantable defibrillator. Possibly he would have some kind of Holter or event monitor, but not necessarily.

Any final thoughts?

The LifeVest is a valuable device, and it is something we are going to see more and more of, particularly with the instituted wait period before we can place a permanent defibrillator in acute MI or acute coronary syndrome patients. Waiting is not necessarily a bad thing, because in some patients, left ventricular function will improve and so they will not need a defibrillator. However, in other cases, people clearly need a permanent device, yet still have to wait. The LifeVest addresses that need and fills that time period. It is a beneficial addition to our armamentarium.

Dr. Goodfellow can be contacted at rgoodfellow17@yahoo.com.