Skip to content

4th Annual Peter Munk Cardiovascular Symposium PT11 (Jan 28, 2012)

  • by

VTS_05_1.VOB

Program he’s going to tell you about anticoagulation atrial fibrillation specifically over the last five to six years we’ve come to realize not every patient with the atrial fibrillation has the same risk not every single patient has the same bleeding risk and then there has been explosion in anticoagulation anticoagulant so it’s going to cover those three topics and

Dr. near hi i’m krishnaiah originally from kerala india the high radioactive zone and my topic is all anticoagulation for atrial fibrillation who and how have no disclosures or conflicts of interest so the objectives of this talk will be to understand the indications for oral anticoagulation it will population to discuss some of these scoring systems now in use like

The chad has to score and to discuss the guidelines for anticoagulation use in some common scenarios like cardioversion and coronary artery disease so i’ve organized the talk like this will go through the need for anticoagulation the different scoring systems the different anticoagulants that are available and then the common scenarios so why anticoagulated or in

Atrial fibrillation the annual risk of stroke in little fibrillation is five percent one in five of all strokes is attributed to atrial fibrillation mortality with stroke in natal fibrillation is three times higher and when you look at the effect of the first ischemic stroke in patients rattle fibrillation sixty percent of these strokes are disabling twenty percent

Of fatal the communist site for a thrombus in the heart and it’ll fibrillations the left it look sorry is the nest okay it doesn’t come okay you see left a clapping dodge this the pathology specimen and this is a transistorized let go so what are the rest i defying scoring systems in atrial fibrillation the last canadian cardiovascular society guidelines clearly

State that every patient with atrial fib flutter or atrial fibrillation should be stratified using a predictive index for stroke like the chad has to score and scoring system for the risk of bleeding and that most patients should receive some form of antithrombotic therapy you’re all familiar with this scoring system the chad is to score we have five criteria and

The maximum score is six the only major criteria is prior stroke is the only major party days prior stroke or transient ischemic attack which is a lot at a score of 2 and the other criteria are heart failure hypertension and diabetes if your score is zero the adjusted stroke rate is one point nine percent per year if you score is six the adjusted stroke rate is 18.2

Percent per year and the guidelines tell us how to and what antithrombotic to use when so if the chat is to score is zero you’re in the low risk so aspirin or no antithrombotic if the chat is to score is one oral anticoagulation or aspirin but oral anticoagulation is preferred if the score is two or more here on the high risk and it’s oral anticoagulation always

The chad is to a score is recommended in the european society of cardiology guidelines and what it does is that the three more criteria are added and they are involvement vascular involvement which is v a is for age so the chat is to includes age more than 75 here there’s an additional category that’s aged more than 65 and sc for is for sex category female sex is

Allotted one one point so in all you can have a maximum score of nine and if your score is zero you’re truly low-risk so the adjusted stoplight is only 0% and that’s the utility of this coding system it helps us to identify the truly low risk category so the recommendation is that the chad has two is two or more anyway you’re going to antigo accolade there’s no point

In going to the chat is to ask if your chad has to score is zero or one then you want to identify the truly low loaders category the group of patients who do not require anticoagulation and it is here that the chad is to ask or helps so the recommendation is that if your score is zero no anticoagulation or aspirin it is chorus one oral anticoagulation or aspirin

Again oral anticoagulation is preferred and if you score is two or more or oral anticoagulation it’s easy to remember because it’s exactly like the chad has to score in terms of what to do with what score this is the this is only scoring system that has really been validated for bleeding in atrial fibrillation there was a previous scoring system called hemorrhages

Which is not well validated so again use the same mnemonic h for hypertension a for abnormal renal and liver function once one point each as for stroke be for bleeding alpha lobby liners efore elderly that’s age more than 65 d drugs or alcohol one point each so you can have a maximum of nine points here so how does this scoring system help the guidelines are not

Clear on exactly how to use this scoring system but what one can do is if you have a score of three or more it indicates a major risk of bleeding so especially for patients who are in the low risk category when you when you have difficulty in deciding between aspirin and anti platelets if the hazard score is three or more probably one can print bend towards giving

Them into santa platelets the other important thing is that you can use the scoring system to fire there’s a reversible factor like you know high blood pressure which is uncontrolled or a drug which is bit or you know or a drug which can or alcohol which can participate increase bleeding we can try and calculate so what are the anti thrombotic drugs that we have

Now we are all familiar with warfarin so what friend works warfarin is effective in reducing the risk of atrial fibrillation related stroke there are 26 trials which are warfarin related the trials of warfarin versus placebo show that there’s a sixty four percent relative risk reduction in the incidence of stroke stroke related to atrial fibrillation antiplatelet

Versus control the relative risk reduction is twenty-two percent warfarin versus antiplatelet agents this is a thirty-nine percent relative risk reduction which means warfarin is clearly more effective than aspirin there is an increase in maze of extracting oil bleeding which is small less than point three percent here but as we all know the risk of interact little

Hemorrhage increases its around 1.5 to one-point-seven percent per year the problem with warfarin is that only fifty to sixty percent of eligible patients receive warfarin because of the problems with monitoring and dose adjustment also for warfarin to be effective it has the inr has to be therapeutic and in clinical trials the time in therapeutic range is only

Sixty to sixty eight percent in general practice it is typically less than fifty percent so what are the new oral anticoagulant works that we have the one that we are all familiar with this diaphragm which is a thrombin inhibitor that is factored to a inhibitor there are three new medications coming in lava rocks urban apixaban and ladakh sabbam daba katrin the

Half-life of dabigatran is 12 to 17 hours it’s predominantly renal excreted and that is why the drug may accumulate when renal function is abnormal there’s no interaction with food the anticoagulant effect is predictable so therefore the fixed set those thing and like warfarin there’s no need for monitoring and there’s no liver toxicity all the data that we have on

Dabigatran is based on one single study rely on like warfarin this study compared warfarin with two doses of dabigatran 110 milligram two times daily and 150 milligrams two times daily the 110 milligram and those was non-inferior in terms of efficacy to warfarin the 150 milligram dose was superior in terms of reducing the combined endpoint of stroke and systemic

Embolism have summarized the results of this trial so that get when one 15 milligram was superior to warfarin for stroke prevention reducing the risk of both ischemic and hemorrhagic stroke the one 10 milligram dose was similar to war film for stroke prevention the 150 milligram dose reduce the risk of cardiovascular mortality in terms of safety and the bleeding

Risk major bleeding was reduced to the one 10 milligram dose the risk of major bleeding was similar with the 150 milligram dose what is important is that the risk of major gastrointestinal bleeding was increased with gabba gabba and 1 50 milligram compared to warfarin therefore if you have a patient who has polyposis or divert closest prescribing diviertan is not a

Great idea warfarin is probably preferable both doses of dabigatran reduce the risk of intracranial hemorrhage compared to warfarin in elderly patients and in patients with renal impairment the recommendation is that renal function should be assessed yearly and navigator and is contraindicated in civ arenal function that sec reactant clearance less than 15 ml per

Minute so dabiq as i delia renal function should be assessed prior to starting dabigatran so how do we switch from one anticoagulant to the other if you wish to switch from warfarin to dabba gap train stop warfarin let diana float down to less than two and then start a baguette run how do you switch from a parent oral anticoagulant to dabigatran if the patient is

On a low-molecular-weight heparin say anak 72 times daily give the morning they’ll say at eight o’clock and give the abbey gap tran at 6pm two hours before the evening dose and discontinued suppose you want to switch from unfractionated heparin to dabba gatling stop the unfractionated heparin and give the abba gator in straight away how do we switch from dabigatran

To a parent role anticoagulant because the duration of action is around 12 hours you have to wait 12 hours after the last dose of dabigatran before starting either unfractionated heparin or low molecular weight heparin how do you convert from dabigatran to warfarin because navigator on is predominantly renal excreted this depends on the creatinine clearance for a

Creatinine clearance less than 15 there’s no recommendation because it’s not derogate and should not be given to these patients for creatinine clearance more than 50 ml per minute start warfarin three days prior to discontinuing dabigatran for creatinine clearance between 31 250 it should be started two days prior to discontinue dabigatran for creating clearance

15 to 30 start warfarin one day prior to that what do you do for patients on dabigatran who are going for surgery so here again this is not the standard recommendation this is from the boehringer company website and these recommendations do what they say is that essentially you have to decide based on the renal function and the type of surgery the patient is going

For and the bleeding risks involved with that type of surgery so in a patient with fairly ok creatinine clearance the recommendation is just stop dabbagh a plan for two doses if the creatinine clearance is between 30 to 50 and the bleeding risk is standard stop target on at least two days before and if it’s less and if the creatinine clearance is less than 30 stop

Daba gap and two to five days before it’s up it’s available on this on google wait it’s not a standard recommendation that’s versus saying yeah and there’s no standard recommendation but there are standard recommendations for surgical diagnostic procedures for patients on aspirin and warfarin for patients at very low risk of stroke it’s common sense that we just

Stop the antibody the antiplatelet agent or the or warfarin let the i not come down and then go ahead with the surgery and the restart 24 hours later when hemostasis is achieved aspirin or clopidogrel according to the ccs guideline should be stopped seven to ten days prior to surgery warfarin for five days if the aina was in the range 2 to 3 what do you do for

Patients who are at high risk of stroke like patients with a prosthetic valve or a traumatic band or heart disease or patients with recent dia or stroke or a chad as t of more than three and also for patients who have a very thrombogenic intra-aortic environment like patients were post for intense surgery these patients require perioperative bridging she stopped

The oral anticoagulation start either unfractionated heparin or low molecular weight heparin until 12 to 24 hours prior go ahead with the surgery and once post-procedure hemostasis is achieved restart oral anticoagulation along with low molecular plane of ufh the three new trials which have been published in the last two years we talked about the relies study

Which is the dabbagh a trend study this is the artists total study which is the epic c-band study and this is rocket af which is published in september 2011 in any gm this is later to rivaroxaban so what are the key features of this new oral anticoagulants this is all in comparison to dabigatran the first thing i should say is that there are all different study

Groups and different inclusion criteria the half-life of all these agents is short it’s around 12 around 12 hours roughly rivaroxaban and rocks urban have an advantage in that they can be given once daily this slide i just put up to show that the inclusion criteria are different for these different agents and there’s no direct head-to-head comparison in any trial

So the evidence we have is for these all these agents have been compared to warfarin answered we have to derive our conclusions based on that data the rocket study on rivaroxaban looked at atrial fibrillation in patients with at least two risk factors or prior transient ischemic attack attack or prior stroke so it is a high-risk category that they looked at so to

Be incorrect to compare that compare these trials i’ve summarized the important points from all these trials low-dose navigate run is non-inferior but has less bleeding as we saw high dose navigator and that is the one 50 milligram pid dosing is superior with similar rates of bleeding lower cardiovascular mortality rubric saban has got its non-inferior to warfarin

With similar risk of major bleeding epic seban is superior this less bleeding less stroke less systemic able ization has lower mortality but it’s a different patient population as compared to rock seban there are higher rates of gi bleeding as we said earlier with dabigatran and also with the rock seban discontinuation rates for all these anticoagulants is in the

Range of twenty percent one recent concern now is that is there a higher risk of michael my cotton faction of dabigatran and this is based on this meta-analysis where it has shown that there’s a higher risk of my cotton faction or acute coronary syndrome with dabigatran as compared to warfarin but this is a paper which came out this month from the rely investigators

From dabigatran they have shown that there’s an increase in myocardial infraction with dabigatran as compared to warfarin but this is non-significant the annual rate of myocardial infraction was in the range of point eight percent of dabigatran and only point six percent with warfarin anticoagulation and cardioversion we all know this in patients who have had atrial

Fibrillation for less than 48 hours and who are hemodynamically unstable urgent care abortion but hemodynamically stable we can go ahead both with pharmacological or with electrical cardioversion for atrial fibrillation or flutter with duration more than 48 hours the recommendation is to oral anticoagulant for three weeks and then continue anticoagulation for four

Weeks post because of my cardinal standing in high-risk patients the patients were described earlier those with prosthetic valves chaps got more than three the best thing to do is a transfer jellicoe and then cardiovert it’s always important to continue antithrombotic therapy for at least four weeks post because of the risk of carol channing what are you doing

Coronary artery disease depends on whether it is stable cid acute coronary syndrome or pci in stable coronary artery disease with low risk of stroke aspirin alone will suffice if the chat is to score is one or more oral antic act or just oral anticoagulation one or therapy will suffice if a patient has had recent acute coronary syndrome and the chat is to score is

Less than one which means you let risk of stroke is low aspirin plus florida girl if the risk of stroke is high triple therapy aspirin clopidogrel and warfarin in pci it’s exactly the same as i could converse intro for patients with low risk of stroke aspirin plus clopidogrel high risk of stroke triple therapy and remember because just like as we discussed earlier

Because of the risk of coronary events though the data is not robust daba katrin is not preferred warfarin is preferred in current director disease and just to tell you that are some smart phone apps there’s a free app chat as to which have on my phone has bled and chad has two vas go to search for bill willingham calculator to get this you won’t get it otherwise

So in somebody will discuss the need for anticoagulation the different scoring systems the different anticoagulants and we went through the all these scenarios and thank you you

Transcribed from video
4th Annual Peter Munk Cardiovascular Symposium PT11 (Jan 28, 2012) By UHN Foundation