Heartfelt with Dr Melissa Walton-ShirleyView all posts »
Take the thrombin-inhibitor exam: Automatically win a million dollars if you get 100% correct!Nov 15, 2010 23:37 EST
Okay, I'm kidding. But I'd really be impressed! So here goes and good luck! You will have 10 minutes to complete the exam. There will be no "phone-a-friend, "50-50," or "let's-ask-the-audience" opportunities. No fair contacting anyone who had anything to do with the ROCKET AF or RE-LY studies. Here goes and good luck!
Mrs Jones is a 70-year-old white female with Alzheimer's disease who was brought into the ER after being involved in a MVA as a passenger. Her husband was the driver. On her list of home medications is rivaroxaban (or feel free to substitute dabigatran if you like). You plan to take her to the OR because her diagnostic peritoneal lavage came back with a little pink tinge. To make certain she is correct about not having taken one of those new direct thrombin inhibitors today, you check a ______________________. The __________________comes back within the normal range, so you call for her to come to the OR. While you are scrubbing, you get an urgent call from the ER physician that her husband, Mr Jones, is crashing. You quickly set up the OR for his arrival and spend about six hours stabilizing him. You finish the surgery, greet the family in the waiting area with the great news, and prepare to take Mrs Jones next.
You finally get Mrs Jones to the OR and realize about an hour into the surgery that she is oozing profusely. You call down to the waiting room and ask, "Did anyone see Ms Jones take any medications this morning?" and the 14-year-old granddaughter says, "You know, I saw Nana taking a pill from her purse in the ER after the doctor left her room." They quickly check her purse, and the only medication bottle present is labeled rivaroxaban (or dabigatran if you prefer). With mild sinus tachycardia and her BP in the 80s, you order four units of packed red blood cells followed by a _______________test to check her level of factor X inhibition. Furthermore, you'd like to know the remainder of time for which she'd be expected to remain anticoagulated on her last oral dose, so you order a ______________________ to see just how many packed cells she's probably going to require. You finish the surgery before any of those tests come back because they are "send-outs" and will require ________________ hours before you can get an answer. You thought about ordering: (a) an activated clotting time (ACT) test; (b) a partial thromboplastin time (PTT) test; (c) both a and b; (d) none of the above because you asked your cardiology consultant, who said, "I don't know, either."
The patient does great because you are a fabulous world-famous surgeon and on postop day 4 Mrs Jones is walking around the hospital having resumed her rivaroxaban (or dabigatran). She turns to speak to the nurse but clutches her chest and falls down in v-fib arrest. She is successfully defibrillated and taken to the cath lab by the same cardiologist who didn't know the answer to the multiple-choice question above. She has a totally occluded LAD. Since she is on rivaroxaban (or dabigatran) she receives a ______________________stent and goes home on triple therapy. She is instructed to stay on a beta blocker, a statin, an aspirin, ticagrelor, and the direct thrombin inhibitor for ___________________months, and then she will continue on with ___________________ and/or ____________________as her permanent ACS secondary-prevention regimen. Because her creatinine clearance has fallen since all of the hypotension and acute tubular necrosis (ATN) she suffered, you consult the pharmacy, who advises you to: (a) reduce the dose of the thrombin inhibitor; (b) keep the same dose (20-mg rivaroxaban daily or dabigatran 150 bid); or (c) discontinue the medication in favor of warfarin.
On postop day 7 she is feeling great. The nurse comes in to give her the prescriptions and discharge medications as written by her physician. The nurse congratulates her because her creatinine has just come back at 0.7, having completely recovered from her ATN. Just before the cardiac monitor is removed, the nurse looks up and Mrs Jones has recurrent atrial fibrillation now with a heart rate of 150 bpm. You reconsult her cardiologist, who electrically cardioverts her the following day. Her EF is well preserved at 65%. Because she refuses to take amiodarone again, declaring it made her "feel awful last time," you give her dronedarone. You (select one of the following): (a) give the same dose of thrombin inhibitor; (b) reduce the dose of the thrombin inhibitor; or (c) switch her to warfarin at a reduced dose.
The patient finally makes it to discharge having been through a long and winding hospital admission. That afternoon, she reaches into her purse to get her "stomach medication" but bemoans the fact that her bottle is empty. When her daughter asks her why she calls it her "stomach medication" when indeed it is her blood-thinner bottle, she says, "Oh, I just put my purple pill in there because I like the size of that bottle. I ran out of my blood thinner two weeks ago."
This scenario contains almost all of the potentially nightmarish issues that one could encounter in the real world now that direct thrombin inhibitors have come to town. I've asked tons of questions to lots of different people today and so far, I've received lots of different answers. Unfortunately, the favorite answer is "We don't know yet." It's interesting to me that the very drug class we've spent a decade awaiting perhaps has suddenly become available way too soon.
I'd like to thank Dr Kenneth Mahaffey, the codirector of cardiovascular research at Duke University. He spoke to me on a separate issue of how compliance with rivaroxaban was established in the ROCKET trial and the specifics of the trial design. I didn't ask him all of my test questions but if I did, I'll bet he could have probably made a million dollars today. And after today's ROCKET AF presentation, Monopoly money at that.
Latest on atrial fibrillation with analysis of ROCKET AF (rivaroxaban) and POM 3 (fish oil supplements); SMART-AV on cardiac resynchronization; PFO closure in CLOSURE I
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