American Society of Hirudotherapy

Contaminated heparin and outcomes after cardiac surgery: a retrospective propensity-matched cohort study

Research article published in PloS one (2014)

Last Updated: June 18, 2026Reviewed by: ASH Editorial Board
Research article — evidence reviewArticle reference
Evidence: Research reportClinical TrialsSafety & Infection ControlKaiser HA et al. · PloS one, 2014

Abstract

BACKGROUND: During 2007 and 2008 it is likely that millions of patients in the US received heparin contaminated (CH) with oversulfated chondroitin sulfate, which was associated with anaphylactoid reactions. We tested the hypothesis that CH was associated with serious morbidity, mortality, intensive care unit (ICU) stay and heparin-induced thrombocytopenia following adult cardiac surgery. METHODS AND FINDINGS: We conducted a single center, retrospective, propensity-matched cohort study during the period of CH and the equivalent time frame in the three preceding or the two following years. Perioperative data were obtained from the institutional record of the Society of Thoracic Surgeons National Database, for which the data collection is prospective, standardized and performed by independent investigators. After matching, logistic regression was performed to evaluate the independent effect of CH on the composite adverse outcome (myocardial infarction, stroke, pneumonia, dialysis, cardiac arrest) and on mortality. Cox regression was used to determine the association between CH and ICU length of stay. The 1∶5 matched groups included 220 patients potentially exposed to CH and 918 controls. There were more adverse outcomes in the exposed cohort (20.9% versus 12.0%; difference  =  8.9%; 95% CI 3.6% to 15.1%, P < 0.001) with an odds ratio for CH of 2.0 (95% CI, 1.4 to 3.0, P < 0.001). In the exposed group there was a non-significant increase in mortality (5.9% versus 3.5%, difference = 2.4%; 95% CI, -0.4 to 3.5%, P  =  0.1), the median ICU stay was longer by 14.1 hours (interquartile range -26.6 to 79.8, S = 3299, P = 0.0004) with an estimated hazard ratio for CH of 1.2 (95% CI, 1.0 to 1.4, P = 0.04). There was no difference in nadir platelet counts between cohorts. CONCLUSIONS: The results from this single center study suggest the possibility that contaminated heparin might have contributed to serious morbidity following cardiac surgery.

Abstract sourced from PubMed (NCBI) for the cited record. See the original publication for the authoritative version.

Publication typeJournal Article
Indexed MeSH termsAdolescentAdultAgedAged, 80 and overCardiac Surgical ProceduresChondroitin SulfatesDrug ContaminationFemaleHeart ArrestHeparinHumansIntensive Care Units

Summary

During 2007 and 2008 it is likely that millions of patients in the US received heparin contaminated (CH) with oversulfated chondroitin sulfate, which was associated with anaphylactoid reactions.

Why This Matters for Hirudotherapy

This single-center retrospective propensity-matched cohort study investigated the clinical outcomes of 220 patients potentially exposed to heparin contaminated with oversulfated chondroitin sulfate during cardiac surgery, comparing them to 918 controls. The study found an association between contaminated heparin exposure and increased serious morbidity, including a composite of myocardial infarction, stroke, pneumonia, dialysis, and cardiac arrest, as well as longer ICU stays. The research evaluates adverse events associated with a specific period of heparin contamination and does not involve leeches, hirudotherapy, or any leech-derived compounds. Therefore, its relevance to the American Society of Hirudotherapy is absent, serving only as an analysis of risks associated with contaminated heparin.

Citation

Contaminated heparin and outcomes after cardiac surgery: a retrospective propensity-matched cohort study

Kaiser HA et al. · PloS one, 2014

Added to ASH library: May 27, 2026 · Site last updated: June 18, 2026

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