Tough calls in cardiology :Dengue fever in a patient with prosthetic valve and warfarin !
Posted Dec 05 2013 12:00am
Oral anticoagulant usage has been steadily increasing for variety of indications.Dengue fever is also appearing in different avatars with low platelet counts and bleeding being a primary risk.
I was recently contacted by a physician , regarding a therapeutic dilemma .A young lady with mitral prosthetic valve and a febrile illness diagnosed as dengue . She has a platelet count of 100,000 .She is on regular warfarin and aspirin .The physician wanted to know , should he stop the OAC and aspirin ?
What are the options ?
Confirm if it is really dengue.
Look for clinical bleeding.INR, platelet function tests are not helpful.
Continue OAC.You can do that in most situations.
Stop OAC only if there is clinical bleeding episode.
Anti-platelet drug usage is more tricky .One may stop it if the trend of falling platelet is steep by at least two serial measurement.(or 50% fall from baseline)
Fresh blood and platelet infusions should be ready .
Finally and most importantly , Inform the patient and family about the difficult decision we are making.
*Is OAC safer than aspirin and clopidogrel in dengue ?
It is believed OAC has no major Impact on platelet function .It may not pose a threat of excess bleeding in the setting of falling platelet levels .(*Evidence base -nil )
Another potential situation : DES and dengue
The number of DES in developing countries are increasing where Dengue is endemic . It is not a surprising to expect both to occur together.
Anti-platelet agents can be problematic .It is better to withhold it during the active phase of dengue.(If the stent has recently been deployed you have no option !)
1. Prosthetic valve , Warfarin Dengue .
2. DES, Dual antiplatelet agents ,Dengue.
They extraordinary events throw a complex therapeutic task .There are only two options .Continue or discontinue ! Whichever way you do , you explain to your clients (patients!) the (un)reality games we play.
My personal option would be , with hold all hematological drugs during the active phase of dengue .
It is better to believe in the natural thrombus fighting force . Leave the job of anti-platelet action to the dengue virus for a week or two and give oral anticoagulants and dual anti-platelet agents a holiday
It may be foolish to rely on the dengue virus to guard against prosthetic valve and DES thrombus , In reality we have to do that !
No reference exists.It is a statistical mind game.Individual assessment should prevail. Either way, if something adverse happens court of law should protect us !