Low molecular weight heparin (LMWH) is proving highly effective in preventing laminitis and reducing the severity of laminitis following colic surgery, according to Belgian researchers.
Prior to the study period, more than 10% of colic surgery patients at the Equine Clinic of the University of Liège developed laminitic pain and lameness following surgery. The majority of those horses had severe cases and had to be euthanized.
Since 1995, however, colic surgery patients at the clinic have been receiving subcutaneous injections of LMWH (in the study, Clexane®; 0.35 mg/kg) daily for three to five days post-surgery. Of the 304 horses treated with LMWH in the scope of the study, only one (0.33%) showed mild signs of lameness and pain related to laminitis. Nine others had a "suspicion" of laminitis development, with hot feet and throbbing pulse in the hoof but no pain or lameness. The one laminitic horse rapidly recovered without further incident.
Unfractionated heparin (UFH) has previously been tested to prevent laminitis, but with questionable benefits, according to Geoffroy de la Rebière de Pouyade, DVM, MSc, researcher at the clinic and primary author of the study. UFH also requires more frequent administration, he said.
"With LMWH, the anticoagulant effects are more predictable and consistent, so blood laboratory monitoring isn’t necessary, as is sometimes the case with UHF," de la Rebière de Pouyade said. "Its subcutaneous delivery also means it reaches an efficient level of concentration faster to prevent the onset of disease. That’s significant, considering that time is crucial when it comes to blocking laminitis."
Currently it appears that LMWH’s preventive actions are due not only to its anticoagulation effects but also its anti-inflammatory role, he said. There may be other factors involved, which will require further investigation.
The development of laminitis is always possible, independent of factors such as kind of colic or level of severity or shock, said de la Rebière de Pouyade. "We recommend LMWH for all horses undergoing colic surgery," he said, adding that this should not preclude the use of other prophylactic measures, such as frog supports and non-steroidal anti-inflammatories.
The study, "Evaluation of low-molecular-weight heparin for the prevention of equine laminitis after colic surgery," was published in the February 2009 edition of the Journal of Veterinary Emergency and Critical Care. The abstract is available on PubMed.
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