02.04 MI Surgical Intervention

This lesson will cover surgical interventions for Myocardial Infarction. This is what happens beyond the initial MONA therapy when we need to re-establish perfusion to the heart muscle.



This quote from Zafari & Abdou introduces this for us. They say: “... initial therapy for acute MI is directed toward restoration of perfusion as soon as possible to salvage as much of the jeopardized myocardium as possible. This may be accomplished through medical or mechanical means, such as percutaneous coronary intervention (PCI), or coronary artery bypass graft (CABG) surgery.” So those are the two procedures we’re going to cover today.



So what’s the difference between Percutaneous Coronary Intervention (or PCI) and Coronary Artery Bypass Graft (or CABG) surgery? Let’s look at PCI first. PCI is used as an emergent intervention in an Acute MI, especially STEMI. We use PCI for anyone who started having chest pain less than 12 hours ago, is currently showing signs of cardiogenic shock, OR it has been more than 12 hours but they’re still showing signs of ongoing ischemia. PCI always starts with angiography then, if needed, proceeds to either balloon angioplasty or stent placement, which we’ll look at in just a second. They can use the femoral or radial artery for access. The goal is to get the patient to the cath lab as soon as possible so that the Door To Balloon time is less than 90 minutes.



A CABG is an open heart surgery. Many people refer to it simply as a “bypass”. The reason someone would get a CABG could be cardiogenic shock as well - depending on how unstable the patient is, it’s possible they may skip PCI and go straight to the OR for a CABG. A patient may also get a CABG for a failed PCI, high-risk anatomy, or if they had some sort of mechanical complication with their STEMI like a rupture of muscles in the heart or an issue with their valves. The purpose of a CABG is to create an entirely new vessel to replace the occluded one. They use a vessel usually from the leg as the graft. As we’ll see in just a minute, they can do single, double, triple, or quadruple depending on how severe their coronary artery disease is.



So looking in more detail at PCI, remember I said it always starts with an angiography. They will access the arterial system via the femoral artery here, up through the aorta to the coronary circulation, or they will use the radial artery, up through the brachial artery and the subclavian into the aorta and coronary circulation. Then they’ll inject dye into the coronary arteries to look for occlusions. You can see here there is a partial occlusion in this artery, which happens to be the left circumflex artery.



Once they’ve identified the problem area, they will typically start with a balloon angioplasty. What they do is insert a catheter with a balloon into the occlusion, then inflate the balloon. As you can see, it compresses the plaque and allows for the lumen of the artery to be opened - restoring perfusion. Sometimes the plaque isn’t as compressible as we would like or sometimes it comes right back when you deflate the balloon. In these cases, cardiologists will opt for stent placement. The procedure is the same - they insert the catheter with a balloon, except now it has a mesh stent around it. When they inflate the balloon, the stent expands, then they deflate the balloon and the stent is left behind to help keep the artery open. Patients with stents need anticoagulation to keep clots from forming around the stent itself.



Now, let’s talk CABG. Remember this is open heart surgery so these patients will have a midline sternal incision. As you can see they’ll take the grafted vessel from the leg and use it to create a new vessel providing blood flow to the heart muscle beyond where it had been blocked. As I said previously, they can do this for multiple vessels, depending on the severity of the coronary artery disease.



So as the nurse, what is your responsibility in caring for these patients after their procedure? For a PCI the big thing is monitoring. They are at risk for arrhythmias, reocclusion, bleeding, perfusion issues, and pneumonia from immobility. If they had femoral access they need to lay flat for 6 hours, radial they don’t have to be flat but need to keep their wrist straight and stay in bed for about 4 hours. We check perfusion distal to the access site for pulses, color, temperature, cap refill, etc. We also check the access site for bleeding or a hematoma. I had a patient once who developed a femoral hematoma and nobody caught it. His body attacked it like it was an infection and it ended up getting necrotic. It was a terrible situation for him, he almost lost his leg. So we check for hematomas and perfusion issues hourly. These patients can be on a regular cardiac telemetry floor as long as they’re stable.



For a CABG, they are also at risk for arrhythmias, reocclusion as well as graft rejection, and pneumonia. But also, they’ve had major surgery, they have a midsternal incision and 4 chest tubes. They will be at risk for infection as well. These patients will have continuous telemetry and hemodynamic monitoring for at least 24 hours and will be in the ICU for a couple of days after their surgery. As always with any procedure, follow your facility policy on how often to do vital signs when they return to your unit.



Now - these procedures are very different. You can tell from the aftercare that one is certainly more severe than the other. But I want you to start thinking in terms of concepts. They are different procedures, but the concepts are the same. You have cardiac and peripheral perfusion - so for both patients you need to be checking pulses, vital signs, assessing for pain, checking the skin temperature and color, and giving BP meds. And for both you need to consider leg positioning, PCI needs to be flat for a while and CABG patients should have their legs elevated to prevent edema. Then there’s a clotting and bleeding risk. They may be getting an anticoagulant, we are monitoring them for bleeding, checking coags, H/H, and assessing for DVT because they’re on bedrest. And also Health Promotion and Patient Education - they need to be taught how to use the incentive spirometer, what their diet and lifestyle change will be, instructions about their medications and activity restrictions, as well as when to notify their provider.
So ultimately, if you can identify concepts that apply to your patient, you can apply interventions that are appropriate based on their situation!



So let’s recap. The #1 goal of these interventions is to reestablish perfusion. PCI is used for emergent reperfusion in STEMI. CABG replaces blocked coronary arteries with a graft in severe cases. And even though the procedures are different, the nursing concepts are the same - that will help you develop a plan of care for your patient. As always, our ultimate goal is to do what’s in the best interest of the patient.



We hope this overview has helped you understand these procedures and why they’re used. Now go out and be your best self today. Happy Nursing!