He has also created what he calls “CAPS-like” designation, with recurrent events despite every conceivable treatment, thrombosis with bleeding, isolated microthrombosis with bleeding, and severe thrombocytopenia.
The only registry for CAPS data (www.med.ub.es/mimmun/forum/caps.htm), kept by the European Forum on Antiphsopholipid Antibodies, shows that only about half of patients had definite CAPS, while the rest were probable cases—the main reason for a lack of confirmation was having no biopsy.
The registry shows that 70% of patients with suspected CAPS are female, and about half have trigger factors, mainly infections and surgical procedures. CAPS most commonly affects the kidneys, lungs, and brain, according to the registry’s data.
Only about half of patients have a history of APS, “which creates another diagnostic challenge,” Dr. Erkan said.
There is some evidence that the presence of aPL makes thrombotic micro angiopathies clinically worse. For instance HELLP Syndrome—a condition during pregnancy involving breakdown of red blood cells, elevated liver enzymes, and a low platelet count—is more serious when the woman is also positive for aPL.
“If an aPL-positive patient develops HELLP syndrome, there is tendency to have an early onset less than 24 weeks,” Dr. Erkan said. “There’s a more severe clinical course. Many patients develop hepatic infarcts. And it does not get better with delivery. These patients require much more aggressive treatment.”
He added, “It’s very clear that if aPL is part of the picture, the prognosis is worse. And I believe this is true for the rest of the thrombotic microangiopathies,” although there is no systemic data on it.
A related phenomenon, known as the “thrombotic storm,” is about to be studied in a trial. Lead researcher Craig Kitchens, MD, of the University of Florida, Gainesville, has hypothesized that large clots produce a thrombotic storm by producing thrombin, decreasing fibrinolysis, increasing coagulation activation products, and speeding up consumption of natural anticoagulant products. They are now recruiting subjects to delve into the topic further.
Deciding on Treatment
Dr. Erkan said that if you’re a rheumatologist and get a call asking for help with a patient with multiple clots, the first question should always be: Is there a history of APS or aPL positivity?
If yes, and the picture looks CAPS-like, “jump on it right away, start treatment as soon as possible,” Dr. Erkan said—especially if there are no other thrombotic risk factors in play.
Some of the medications used in CAPS patients include anticoagulation, corticosteroids, intravenous immunoglobulin, plasma exchange, rituximab, and cyclophosphamide—but the approach depends on the clinical features, and there are no systematic controlled data.
