Transcription
Hi, this is Better Tighty and Managed Pilates from the Minneapolis Heart Institute and the Cardiovascular Innovations Foundation, presenting a case that defines the limits of non-CT or coronary interventions. This is a case of enlarged RCA.
The patient presented with an acute inferior STEMI and was found to have a large thrombus in the middle distal RCA. He did have improvement in symptoms when he arrived at the cath lab, but he still had some ongoing issues. We were able to wire the right coronary artery using a radial axis and then an Amplatz 1 guide catheter. We wired it and then did intravascular ultrasound. Intravascular ultrasound showed no significant calcification of the vessel, but there was a large filling defect, probably plaque and/or thrombus, in the mid and proximal right coronary artery.
Given the patient's ongoing symptoms, we decided to attempt thrombectomy. We initially used an Export aspiration catheter, but this was unsuccessful. We then used a guide catheter extension in an attempt to aspirate the thrombus, but once again, this was unsuccessful. We even inserted a filter wire distal to the thrombus, then deployed it and pulled it back into the guide catheter extension in an attempt to capture the thrombus, but unfortunately, that failed as well. Also, during all those attempts, digital movement of the thrombus resulted in compromise of the distal flow.
As a last resort, we tried to use a laser to create a channel through the thrombus, which was unsuccessful. Moreover, the patient did have severe EKG changes—both ST segment depression as well as ST segment elevation—and then developed ventricular fibrillation multiple times, requiring defibrillation as well as intubation. He did have hypotension afterwards, likely due to RV infarction. He received multiple doses of epinephrine, which, after administration, resulted in transient hypertension, but then the patient would slowly drift down again and then require additional epinephrine. To the point that, after consulting with advanced heart failure, we called for a PROTECT Duo right ventricular assist device.
In the meantime, however, we did start the patient on an epinephrine drip. There is some data that epinephrine may be favorable for supporting the right ventricle. After starting the drip, the patient's pace and hemodynamics actually stabilized, even though he continued to have some ST segment changes, but he was able to be dismissed to the intensive care unit. The following day, his hemodynamics had improved.
How to manage a large coronary thrombus? The first goal is to restore coronary flow. If there is under-grade flow, as was the case in this patient, and the question is whether the patient has a large thrombus—there was a large thrombus in this case—if it's a small thrombus, then balloon angioplasty is the way to go. But if there is a large thrombus, if there is no significant ongoing ischemia, one option, which we could have done and retrospectively should have done in this case, is administering strong antithrombotic management, usually with a glycoprotein IIb/IIIa inhibitor and heparin, and then repeating angiography in two to three days. This intensive antithrombotic management might actually lead to a resolution of the thrombus, and then PCI would be much, much safer.
But occasionally, if the patient continues to have ongoing ischemia, then attempts to remove the thrombus are done either with thrombectomy or with laser, but this does carry the risk of embolization and dysfunction, as was the case in our patient.
In summary, large thrombi do carry a high risk for complications. There is the possibility of embolization during thrombus aspiration attempts that can lead to right ventricular infarction. Therefore, in such cases of thrombi, if there is preserved under-grade flow and no significant pace and symptoms, one option is conservative management with administration of glycoprotein IIb/IIIa inhibitors as well as heparin and repeated angiography in two to three days to allow resolution of the thrombus. Finally, if, despite that, there is distal embolization and in the right coronary artery right ventricular infarction, epinephrine may be very useful for supporting the right ventricle, but occasionally, ventricular support devices like the Impella RP or the PROTECT may be required. Thank you.