What's Hot in Clots: July 2025

I recently returned from the International Society of Thrombosis and Haemostasis (ISTH) 2025 Congress. ISTH is one of my absolute favorite meetings of the year. This time, however, I was sidetracked for several reasons. We were relocating to a new place, and more importantly, there was so much unrest around the world, and I was worried about physician friends and extended family. I continue to pray for peace for all.

Here are my summaries for this month:

Apixaban vs rivaroxaban for treatment of venous thromboembolism (VTE): We have a clear winner

To me, this was the single most important study at ISTH. This open-label clinical trial randomized patients with acute VTE to apixaban vs rivaroxaban. Although there was no significant difference in effectiveness, the risk of clinically relevant bleeding events was reduced by over 50% with apixaban compared with rivaroxaban (odds ratio: 0.44). Barring any surprises when the full-text paper becomes available, one wonders if apixaban should be the default treatment in acute VTE. Read more about the study design.

VQ SPECT, planar SPECT, or CPTA for diagnosis of PE

This was another clinical trial at ISTH that I found interesting. The caveat is that the study was terminated prematurely due to slow recruitment after 603 individuals were randomized. The failure rate (i.e., 3-month VTE in patients deemed negative for pulmonary embolism) was very low in all study arms. However, the findings for non-inferiority are inconclusive. Full results have not been published, yet. Read more about the study design.

An entire issue of JACC dedicated to the ACS guidelines!

I’m not including this just because I’m a part of JACC—I had not seen this before for any other guideline or from other journals. It covers the full guideline document, which is a great piece and comes in place of the prior NSTEMI and STEMI old documents and focused updates. In addition, there are multiple commentary pieces and summaries that put this new guideline into context and share specific focus areas such as lipid-modifying therapy, regional perspectives, and more. There is also one about antithrombotic therapy. Full issue is here, with the full ACS guideline document here and the antithrombotic therapy recommendations here.

Prothrombin complex concentrate (PCC) more effective than frozen plasma for post-cardiac-surgery coagulopathic bleeding

Among 420 randomized participants in a clinical trial of patients post-cardiac surgery, PCC had higher hemostatic effectiveness and resulted in fewer transfusions as compared with frozen plasma. Read more here.

Updated guidelines for the treatment of pediatric VTE

I have limited expertise in pediatrics—but when a major guideline is released, it’s an important step forward, especially considering that the burden of in-hospital pediatric VTE is on the rise according to some reports. Read more.

Behnood Bikdeli, MD, MS