Abstract: SA-PO824
Biological Parameters in Biopsy-Proven Renal Thrombotic Microangiopathies
Session Information
- C3G, TMA, MGRS, Amyloidosis, and More
October 26, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Halimi, Jean-Michel, Centre Hospitalier Regional Universitaire de Tours, Tours, Centre-Val de Loire, France
- Maisons, Valentin, Centre Hospitalier Regional Universitaire de Tours, Tours, Centre-Val de Loire, France
- Chardon, Etienne, INSERM U1327, Tours, Centre-Val de Loire, France
- Caillard, Sophie, Universite de Strasbourg, Strasbourg, Grand Est, France
- Frimat, Marie, Universite de Lille, Lille, Hauts-de-France, France
- Mesnard, Laurent, Hopital Tenon, Paris, Île-de-France, France
- Chauvet, Sophie, Hopital Europeen Georges Pompidou Cancerologie, Paris, France
- Piver, Eric, Centre Hospitalier Regional Universitaire de Tours, Tours, Centre-Val de Loire, France
Group or Team Name
- MATRIX Consortium Cohort Study (NCT05991245).
Background
Thrombotic microangiopathies (TMA) are suspected in the presence of anemia, high LDH, low haptoglobin, thrombocytopenia and schistocyte>1%. The kidney is the most frequently affected organ. However, interpreting biological parameters in this context is unclear.
Methods
Biological parameters were studies in 967 patients with biopsy-proven renal TMA from 25 French hospitals during the 2009-2023 period.
Results
Median age was 49 (IQR: 36-64), 53.2% were male. All TMA KDIGO causes were represented. Biomarker sensitivity (ie. proportion of patients with the parameter) ranked as follows: anaemia (81.7%), high LDH (75.4%), low haptoglobin (53.7%), thrombocytopenia (40.3%), schistocytes>1% (34.0%) but varied widely according to fibrinogen, prothrombin time (PT) and serum creatinine. The sensitivity of these biological parameters was preserved (>75%) only in patients with both fibrinogen levels <5 g/L and serum creatinine ≥300 µmol/L, ie 29% of the population.
Laboratories used 11 different ways to report schistocytosis: various threshold values and reporting (binary, qualitative, semi-quantitative, quantitative, adjective-based vs numerical) were found. Schistocyte>1% had been used as the sole criterion, suspicion of TMA would have been missed in 66.0% of patients (23.8% to 86.4% according to TMA causes).
Unsupervised cluster analysis revealed that biological parameter structuring is strongly linked to specific renal TMA causes. Using fibrinogen, serum creatinine, anemia, LDH and haptoglobin, A simple algorithm identified patients with infrequent (sensitivity <10%) or very frequent (sensitivity: 75-90%) phenotypes.
Conclusion
Schistocyte reporting varies widely and “schistocyte>1%” misses two-thirds of renal TMAs. Biological parameters’ results should be interpreted according to fibrinogen, creatinine and PT but careful analysis of these parameters can help differentiate among TMA causes. A simple algorithm provides crucial information regarding the necessity of kidney biopsy, indicating when renal TMA is either unlikely or highly probable.