Acute Coronary Syndromes (ACS): Treatment and Assessment

by Julianna Jung, MD, FACEP

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    00:01 Hello.

    00:02 Now, we're gonna talk about acute coronary syndromes, a very common and important problem in the Emergency Department.

    00:11 So coronary syndrome is actually very common.

    00:13 In the United States, there are more than three quarters of a million cases of coronary syndromes each year.

    00:19 The mean age is 68 years of age.

    00:22 But the inner quota ratio goes from 56 to 79.

    00:25 So this is really a disease process that affects pretty much all adults.

    00:30 There is a male to female predominance.

    00:32 So for every 10 patients with coronary syndromes, 6 will be men, 4 will be women, and 70% of coronary syndromes are non ST segment elevations.

    00:44 Meaning, these are not acute MIs that are getting rushed to the Cath Lab.

    00:49 These are patients who have more subtle findings or in some cases even no findings on their initial ECGs.

    00:55 So recent trends, when you look at the epidemiology of coronary syndromes shows that we’re actually seeing fewer and fewer massive ST segment elevation events and more and more non ST segment elevation events.

    01:10 So again, we’re not seeing big acute coronary occlusions, we are seeing more subtle ischemia.

    01:15 Short term mortality is stable across the boards, so there's not really been any change in the likelihood of people dying from coronary syndromes in the short term.

    01:25 But fortunately, long term survival is improving and that’s largely due to improvements in diagnosis, short term and long term management for these patients.

    01:36 So what is a coronary syndrome? Very simply, an acute coronary syndrome is any new condition that leads to inadequate myocardial perfusion relative to demand.

    01:49 So if the heart’s not getting enough oxygen, it’s not getting as much as it needs metabolically that is a coronary syndrome.

    01:56 Now, most coronary syndromes start with chest pain.

    01:59 However, among patients with chest pain, the vast majority are actually not having acute coronary syndromes, although there is of course a significant overlap in the middle.

    02:10 Among patients with coronary syndromes, there’s a continuum of disease.

    02:14 So patients may have unstable angina, patients may have non ST segment elevation myocardial infarctions, or patients may have ST segment elevation myocardial infarctions.

    02:26 So this is a continuum of disease acuity and there's different management depending on the patient's clinical presentation.

    02:36 When we look at unstable angina, we're generally talking about ischemic chest pain that occurs either while the patient’s at rest or with levels of exertion that they're normally able to tolerate.

    02:49 I go out for a-two-mile walk every day and usually I'm fine but in the past week, I'm getting chest tightness or getting short of breath within half a mile and I have to sit down.

    02:59 That's an example of impaired exercise tolerance.

    03:03 For these patients, when they come see you in the Emergency Department will often have no ECG findings or their ECG findings will be very non-specific and their lab abnormalities will be negligible as well.

    03:14 So these patients are not gonna typically present to you with elevated troponins.

    03:19 By contrast, patients who have NSTEMIs or none ST elevation MIs, these are patients who can have ischemic chest pain in any setting, it might only be with exertion, it might be at rest.

    03:33 When they present, they will typically have some degree of EKG changes, although a small percent will have none.

    03:40 However, those changes are gonna usually be ST segment depressions.

    03:44 They're not gonna be elevations because that’s a different type of infarct.

    03:47 And these patients are really characterized by their elevated troponins.

    03:51 So they come in with chest pain, they have EKGs that are not definitively diagnostic if an MI, but they show that they have elevated troponins and that’s evidence of coronary infarction.

    04:03 That’s our NSTEMI patient.

    04:05 And then lastly, we have our STEMI patients or patients with ST elevation MIs And these patients again, have chest pain that might occur at rest, it might occur during exertion but it's typically a single acute event and they're gonna come in with the classic ST segment elevations that we all learned in medical school characterized acute myocardial infarctions.

    04:29 Now, for these patients, they will typically have elevated troponins, but we won’t even see that in the Emergency Department, because patients with STEMIs get emergent definitive treatment for their coronary disease and they’re not gonna be hanging around the ED for long enough for us to see there troponins go up.

    04:45 So that’s gonna be more of an inpatient finding and we’re gonna make that diagnosis based on EKG findings alone while they're in the Emergency Department.

    04:56 So when we see patients with chest pain and we suspect coronary syndromes, we always wanna get a rapid history and physical.

    05:03 We wanna know what was happening when the pain started.

    05:06 How did it start? What did it feel like? What are all the circumstances surrounding this presentation and we wanna get an ECG and we wanna do that very, very quickly typically within 10 minutes of the time the patient arrives to the door.

    05:20 If they're having a STEMI, then they need to get immediate definitive management.

    05:25 So a STEMI tells you that the patient has complete occlusion of a coronary artery that is causing transmural, full thickness infarct of part of their heart.

    05:35 That's bad, right? Time [00:05:36.12 is] myocardium.

    05:38 So these patients are gonna go directly to cardiology and get definitive management which we’ll talk about in a minute.

    05:45 If they’re not having STEMIs we have a little bit more time to think about them and we’ll go through that algorithm second.

    05:50 So here's a perfect example of a STEMI.

    05:53 You can see in all the anterolateral leads so V2, V3, V4, V5, V6 also leads one in AVL, you see tombstones, right? These are the classic convex ST segment elevations that we all learned about in medical school.

    06:11 This is a STEMI.

    06:14 So once again, isoelectric baseline which is highlighted in black, that's the PR segment and the TP segment, right? That's where the isoelectric baseline is supposed to be.

    06:25 If you look at the ST segment one millimeter after the QRS complex which is by convention where we measure it, you can see with the new highlight that that ST segment is way up in the air above that isoelectric baseline, so it’s higher than it should be.

    06:41 Isoelectric baseline ST segment up above it That’s an ST segment elevation and again on this ECG, we’re seeing it not just in the leads that are outlined but in several leads.

    06:53 In order to diagnose somebody with a STEMI.

    06:55 I mentioned before we’re using the ECG as our primary diagnostic tool.

    06:59 So the patient of course has to have a history that’s compatible with ischemic chest pain and they have to have ST segment elevation in two or more anatomically contiguous leads.

    07:10 So in the anterior leads which are V2 through V4, the lateral leads which are V5 and 6 and 1 and aVL or the inferior leads which are 2, 3 and AVF.

    07:22 They have to have ST segment elevations in two or more anatomically contiguous leads.

    07:28 We’re typically looking for 2 millimeters in men and 1.5 millimeters in women in especially V2 and V3 because that’s a common place where you see non pathologic ST segment or J point elevation.

    07:42 In all the other leads, we're looking for one millimeter of ST segment elevation.

    07:47 So when you're measuring your ST segment, you wanna make sure that you know, one, what your anatomy is.

    07:52 So you wanna know which leads go with which anatomical piece of the heart and again, anterior is gonna be V2, V3, V4, lateral is gonna be V5, V6, 1 and AVL, and inferior is gonna be 2, 3 and AVF So we wanna know if they’re anatomically contiguous and we wanna know how high the ST segment is elevated relative to the standard for that particular lead.

    08:21 The second criterion for ST segment elevation diagnosis is ST segment depression in V1 and V2 and very simply, that represents posterior infarction.

    08:32 And if you think about it, we always put ECG leads on the anterior part of the chest but if you're infracting the back of your heart that image on your surface ECG is gonna be inverted, it's gonna look upside down and backwards.

    08:47 So ST segment elevations that are occurring in the back of the heart will look like depressions when they’re measured from the front of the body.

    08:56 That's why V1 and V2 are special and ST segment depressions and those leads are considered to be ST elevations for the posterior of the heart.

    09:07 The final criterion is a new left bundle branch block, which of course this ECG does not demonstrate.

    09:12 But if the patient has new development of QRS widening in a left bundle pattern that is also highly suggestive of a myocardial infarction.

    09:21 So once the patient meets those criteria, what are we gonna do about it? Well first and foremost, we are very rapidly going to revascularize their coronary arteries.

    09:32 So again, ST segment elevation means you've got complete occlusion of an artery that is causing transmural infarction of the heart.

    09:40 That is not good.

    09:42 We need to get that artery opened back up and we need to save whatever myocardial tissue we can that’s distal to it.

    09:49 The best way to accomplish that by far is with Percutaneous Coronary Intervention or PCI.

    09:55 That refers to going to the Cath Lab, performing angiography, inserting stents to hold the coronaries open.

    10:04 The other option that’s available is thrombolysis.

    10:06 That involves giving a clot busting drug systemically.

    10:09 However, it's not as effective as PCI and it’s not as safe.

    10:13 So anytime you have the option of performing PCI, that's always gonna be the preferred technique, provided you can do it in a timely manner.

    10:22 So the goal door to balloon time for PCI should be under 90 minutes.

    10:27 If you're over 90 minutes, you don't think you’re gonna be able to get the patient to a center where they can perform PCI in a 90-minute timeframe, unfortunately, that piece of heart that’s distal to that occluded coronary artery is gonna die, so you need to go to plan B which is gonna be again, systemic thrombolysis.

    10:47 Now, we're using that less, and less, and less in modern times, because there's more and more centers that are capable of performing PCI.

    10:54 But if you happen to be practicing in a limited resources setting, thrombolysis might be your only option to save the threatened piece of the patient’s myocardium.

    11:04 So it is something we should be aware of in our armamentarium even though we prefer PCI.

    11:11 In addition to revascularization while you're waiting for your patient to go to the Cath Lab, you wanna make sure that you optimize their medical management.

    11:20 So we're gonna give them antiplatelet therapy in the form of aspirin and an antiplatelet agent such as clopidogrel or ticagrelor.

    11:28 We can also think about an oral beta blocker if there's no contraindication to doing that.

    11:33 Now, beta blockers in the acute setting are not nearly as important as they are long-term following the myocardial infarction.

    11:40 But for patients who have significant hypertension or tachycardia on arrival, it might decrease strain on the heart and ultimately improve their outcomes.

    11:48 So you can think about it although it's not mandatory to give up front.

    11:52 We do definitely wanna provide anticoagulation usually in the form of unfractionated heparin for patients who are gonna be going to the Cath Lab for the simple reason that in the event they have a bleeding complication, we wanna be able to turn it off and not have uncontrolled anticoagulants kicking around in their system, preventing us from being able to control their bleeding.

    12:15 And then lastly, we wanna think about analgesia.

    12:18 So typically either nitroglycerin or morphine is used if there's not a contraindication.

    12:23 Now, morphine has been a little bit controversial lately, because of some studies that have showed adverse outcomes associated with morphine.

    12:30 But it’s still a reasonable thing to think about for a patient with chest pain that’s [00:12:34.10 refracturating in nitroglycerin] because we do wanna alleviate our patient’s suffering in addition to giving them the definitive treatment that they need.

    12:42 So that covers management for STEMI.

    12:44 Now, let’s go back to our ACS algorithm and consider the opposite possibility.

    12:48 So we perform our history and physical, were concerned about coronary disease.

    12:52 We’ve performed our ECG looking for a STEMI but now we haven't found one.

    12:57 There is no criteria to send the patient to the Cardiac Catheterization Lab.

    13:01 So our next maneuver is gonna be to assess their level of risk for coronary disease.

    13:08 So for patients who don't have STEMIs but you're still concerned about coronary syndromes, we wanna assess their level of risk for coronary disease.

    13:17 This is our first priority in patients in whom we suspect a coronary syndrome who we’re not sending to the Cath Lab.

    13:24 There are a number of different decision tools out there to help us do that but the one we use most commonly in the ED that’s been validated for use in our setting is called the heart score.

    13:33 It's consist of five elements which conveniently spell the word heart.

    13:37 So the first element is history.

    13:39 If your patient has a very concerning history, they get two points.

    13:43 If they have a so-so history, they got one, and then if the history is minimally suspicious, they get zero.

    13:50 For ECG changes, it's based on ST segment depressions.

    13:54 ST depressions are pretty characteristic of coronary ischemia, and there aren’t a lot of other conditions that cause those, so you get two points for those.

    14:02 Whereas, if you have nonspecific changes or no changes, you get fewer points.

    14:08 Age is the next variable.

    14:10 Age over 65 gets you 2 points, 45 to 65 gets you 1, and if you're under 45, you’re much less likely to have a coronary syndrome, so you get no points for that.

    14:21 Risk factors address the classic elements of risk for coronary disease and we’ll talk about those in just a few minutes.

    14:29 If you have one or two risk factors, you get one point, greater than three, you get two points, no risk factors, obviously, you get none.

    14:36 The last variable is our troponin.

    14:39 So if your troponin is more than three times the upper limit of normal for your institution, that gets you two points.

    14:46 If you have a small troponin leak just a little bit of an elevation that's less than three times that upper limit of normal, you get one point and normal troponins gets you no points.

    14:56 Now, like I said, this is not the only tool that’s out there, but it is a very useful tool that has been validated in the Emergency Department to predict MACE or Major Adverse Cardiac Events and that's really our goal.

    15:10 We wanna identify the patients who are at high risk of having another MI, of having an adverse outcome like death.

    15:19 So that we can address their needs urgently and we wanna identify low risk patients so we can send them home and not perform a lot of unnecessary tests on them.

    15:28 So that’s the purpose of this type of a scoring system.

    About the Lecture

    The lecture Acute Coronary Syndromes (ACS): Treatment and Assessment by Julianna Jung, MD, FACEP is from the course Cardiovascular Emergencies and Shock. It contains the following chapters:

    • Introduction
    • STEMI

    Included Quiz Questions

    1. ACS includes STEMI, NSTEMI and stable angina
    2. It is common in the United States.
    3. It most commonly affects adults.
    4. It is more common in men.
    5. About 70% of cases do not show ST-segment elevations.
    1. Ischemic chest pain occurring with previously tolerated levels of exertion
    2. Elevated troponin levels occurring in association with chest pain
    3. ST-segment elevations when chest pain is present
    4. Ischemic chest pain in any setting
    5. Elevation of CK-MB levels occurring in association with chest pain
    1. Irreversible injury to cardiac muscle has occurred.
    2. It is the the equivalent of angina.
    3. It may revert to a non-STEMI (NSTEMI).
    4. The limb leads of an ECG are the best indicators of STEMI.
    5. It is increasing in incidence in the USA compared to NSTEMI.
    1. Inferior
    2. Anterior
    3. Left lateral
    4. Right lateral
    5. Posterior
    1. ST-elevations should be observed in at least one lead.
    2. Elevations should be more than 2 mm in men in V2-V3 leads.
    3. Elevations should be more than 1.5 mm in women in V2-V3 leads.
    4. Elevations must be at least 1 mm in limb leads and most precordial leads.
    5. Non-pathologic ST elevations are commonly seen in V2-V3 leads.
    1. Less than 90 minutes
    2. 140 - 160 minutes
    3. 120 - 140 minutes
    4. 100 - 120 minutes
    5. 90 - 100 minutes
    1. Tachycardia
    2. History
    3. ECG
    4. Age
    5. Risk Factors

    Author of lecture Acute Coronary Syndromes (ACS): Treatment and Assessment

     Julianna Jung, MD, FACEP

    Julianna Jung, MD, FACEP

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    Very useful
    By Andrew P. on 24. January 2020 for Acute Coronary Syndromes (ACS): Treatment and Assessment

    Very useful information delivered in a direct and easy to understand manner.