AATS helps heart surgeons diagnose and manage heparin-induced thrombocytopenia
A new expert consensus document released at the American Association for Thoracic Surgery (AATS) 106th Annual Meeting aims to address longstanding gaps in the management of heparin-induced thrombocytopenia (HIT) in cardiac surgery patients.[1]
Cardiovascular Business spoke with lead author Subhasis Chatterjee, MD, associate professor of surgery and director of the thoracic surgical ICU and ECMO program at the Texas Heart Institute at Baylor St. Lukes. He said HIT remains one of the most serious complications associated with cardiac surgery. The condition occurs when exposure to heparin, a commonly used anticoagulant, triggers an immune response that causes the body to form antibodies against platelet factor complexes, leading to thrombosis and potentially life-threatening complications.
“Heparin-induced thrombocytopenia is a devastating problem,” Chatterjee said. “It affects about 1% of all cardiac surgery operations, and it’s associated with much worse outcomes and low survival.”
Although existing HIT guidelines are considered comprehensive, Chatterjee said they lacked direct input from cardiac surgeons and intensivists even though cardiac surgery accounts for an estimated 30-40% of HIT cases. The new consensus was developed specifically to address the unique clinical challenges facing this patient population.
The document was created by a multidisciplinary panel of 17 experts representing six specialties, including nine cardiac surgeons, intensivists and hematologists. Members involved in previous hematology guideline efforts also participated.
One of the primary goals of the consensus was to reduce both the overdiagnosis and the under-recognition of HIT in postoperative cardiac surgery patients. Chatterjee said clinicians frequently order heparin antibody testing too quickly after surgery, even though platelet counts commonly decline in the immediate postoperative period.
“We expect 50-60% of patients after heart surgery to have their platelets drop down,” he explained.
Current guidelines generally recommend starting a non-heparin anticoagulant when HIT antibody testing is initiated. However, Chatterjee said this has medical-legal concerns for physicians. So the new consensus emphasizes a more selective and evidence-based diagnostic strategy, particularly regarding when to order antibody testing and when to begin alternative anticoagulation therapy.
Another key issue highlighted in the document is the high false-positive rate associated with HIT antibody testing. Chatterjee said antibody tests may have false-positive rates ranging from 60-80%, making clinical judgment essential before escalating therapy.
The consensus also calls attention to the importance of evaluating patients’ preoperative exposure to heparin. Chatterjee noted that many clinicians assume the triggering heparin exposure occurs during surgery itself, but patients may have already have been exposed through prior cardiac catheterization procedures, acute coronary syndrome treatment or other hospital-based therapies.
The guidance outlines clinical signs that should heighten suspicion for HIT. In cardiac surgery patients, HIT may present more commonly with arterial thrombosis rather than the deep vein thrombosis (DVT).
“The obvious thing that you need to look for is thrombosis,” Chatterjee said. “If you see thrombosis rather than just a drop of the platelet count, that escalates your intervention.”
He recommended that clinicians closely examine patients at least twice daily for evidence of thrombotic complications.
The consensus also reinforces the importance of recognizing the classic platelet count pattern associated with HIT. Following cardiac surgery, platelet counts typically decline for several days before rebounding around postoperative day four. But he said a second platelet drop occurring around postoperative days five through seven, known as a biphasic platelet pattern, should raise strong suspicion for HIT.
Chatterjee said clinicians observing this pattern should calculate a patient’s 4T score, discontinue heparin exposure and strongly consider antibody testing.
The authors believe the new consensus document will help standardize care for cardiac surgery patients while balancing thrombosis prevention against bleeding risk in a population with uniquely complex perioperative management needs.
Dave Fornell has covered healthcare for more than 17 years, with a focus in cardiology and radiology. Fornell is a 5-time winner of a Jesse H. Neal Award, the most prestigious editorial honors in the field of specialized journalism. The wins included best technical content, best use of social media and best COVID-19 coverage. Fornell was also a three-time Neal finalist for best range of work by a single author. He produces more than 100 editorial videos each year, most of them interviews with key opinion leaders in medicine. He also writes technical articles, covers key trends, conducts video hospital site visits, and is very involved with social media. E-mail: [email protected]