Study links clot waveform changes to hypercoagulability in canine IMHA
Bottom line
Dogs with immune-mediated hemolytic anemia may show clot waveform patterns consistent with hypercoagulability on the turbidimetric ACL-TOP 300 analyzer, according to a retrospective study of 35 cases from 2018 to 2022. The study, published in the Journal of Veterinary Emergency and Critical Care, found increased clotting parameters in dogs with IMHA, adding to a growing body of evidence that these patients face substantial thrombotic risk and may benefit from closer coagulation assessment alongside standard IMHA workups. The authors frame clot waveform analysis as a potentially useful adjunct for identifying dogs that could need antithrombotic therapy, rather than a replacement for established diagnostic criteria or treatment protocols. (pmc.ncbi.nlm.nih.gov)
Why it matters: Thromboembolic disease remains one of the most important complications in canine IMHA, and prior consensus guidance has already emphasized thromboprophylaxis in many cases despite limited precision tools for risk stratification. Earlier veterinary studies using thromboelastography, viscoelastic monitoring, microparticle analysis, and other coagulation methods have repeatedly pointed toward a hypercoagulable phenotype in IMHA. This new report suggests clot waveform analysis, generated from a routine coagulation platform already described in canine patients, could offer another practical way for clinicians and clinical pathologists to detect prothrombotic changes and refine monitoring in high-risk dogs. (onlinelibrary.wiley.com)
What to watch: The next step is whether prospective studies can show that ACL-TOP 300 clot waveform findings predict thromboembolic events, treatment response, or survival strongly enough to change antithrombotic decision-making. (pubmed.ncbi.nlm.nih.gov)
Key facts
- Study type
- Retrospective study
- Sample size
- 35 dogs
- Condition
- Immune-mediated hemolytic anemia (IMHA)
- Study period
- 2018 to 2022
- Analyzer
- Turbidimetric ACL-TOP 300
- Main finding
- Clot waveform patterns were consistent with hypercoagulability
- Journal
- Journal of Veterinary Emergency and Critical Care
- Clinical implication
- May help identify dogs that could need antithrombotic therapy
A new retrospective study adds fresh data to a familiar clinical problem in canine IMHA: thrombosis. Reviewing 35 dogs with immune-mediated hemolytic anemia from 2018 to 2022, investigators reported clot waveform analysis findings on the turbidimetric ACL-TOP 300 analyzer that were consistent with a hypercoagulable state. The work suggests that waveform-derived coagulation parameters could help identify IMHA patients that warrant especially close attention for antithrombotic management. (pmc.ncbi.nlm.nih.gov)
That conclusion fits with years of concern about thromboembolic disease in IMHA. ACVIM consensus statements describe IMHA as a high-morbidity, high-mortality disease in dogs, and treatment guidance has highlighted thrombosis prevention as a key part of case management. Earlier retrospective work found thromboemboli commonly at necropsy, while reviews of pathophysiology have outlined multiple prothrombotic drivers, including hemolysis-associated cell damage, platelet activation, inflammatory signaling, and procoagulant membrane surfaces. (pmc.ncbi.nlm.nih.gov)
The new paper also builds on prior University of Minnesota-associated work around the ACL-TOP platform. Earlier studies evaluated the analyzer’s performance in dogs and cats, compared standard clotting tests with novel clot waveform parameters, and characterized clot waveform changes in other canine coagulopathies. Those studies suggested waveform analysis can reveal information not captured by PT and aPTT alone, including associations with bleeding risk in some disease groups. In that context, applying the same platform to IMHA is a logical next step. (onlinelibrary.wiley.com)
Based on the abstracted report, the 35-case IMHA study found increased clotting parameters on clot waveform analysis that aligned with hypercoagulability. The source summary does not indicate that the study established outcome-based cutoffs or proved that waveform abnormalities directly predict thrombosis, but it does position the assay as a possible aid in identifying dogs that may need antithrombotic therapy. That distinction matters: this appears to be a characterization study, not yet a practice-changing interventional trial. (pmc.ncbi.nlm.nih.gov)
Outside this paper, the broader literature offers supportive, if still incomplete, context. A 2022 retrospective study using a point-of-care viscoelastic coagulation monitor found dogs with primary IMHA had parameters consistent with hypercoagulability compared with healthy controls, and most IMHA dogs were classified as hypercoagulable overall regardless of the reference interval used. More recently, investigators have also reported fibrinolysis resistance in dogs with IMHA using tissue plasminogen activator-modified thromboelastography, reinforcing the idea that thrombotic risk in these patients may reflect both increased clot formation and impaired clot breakdown. (pubmed.ncbi.nlm.nih.gov)
Expert-style commentary from the formal literature has been broadly consistent on the clinical challenge, even if not directed at this exact paper. ACVIM treatment guidance includes an algorithm for antithrombotic drug selection in dogs with IMHA, underscoring how central thromboprophylaxis has become in case management. At the same time, the guidance notes limits in the evidence base for selecting, dosing, and monitoring anticoagulants, which is why additional laboratory tools that improve risk stratification would be useful if validated prospectively. (academic.oup.com)
Why it matters: For veterinary professionals, the practical question is not whether IMHA can be prothrombotic, but how to identify which dogs are at highest risk, when to escalate antithrombotic therapy, and how to monitor response. If clot waveform analysis on a routine analyzer can supply clinically meaningful information beyond standard PT and aPTT, it could be attractive for referral centers and hospital labs that already use ACL-TOP systems. But the field still needs prospective data tying these waveform abnormalities to hard outcomes such as confirmed thromboembolism, transfusion needs, ICU course, or survival before the test can move from interesting signal to standard decision tool. (journals.sagepub.com)
What to watch: Watch for full-text publication details, larger multi-center validation, and prospective studies testing whether clot waveform metrics can predict thromboembolic events or guide antithrombotic selection more accurately than current coagulation testing alone. (pubmed.ncbi.nlm.nih.gov)