The frequency of heparin induced thrombocytopenia in patients undergoing elective cardiac bypass surgeries.
OBJECTIVE
To determine the frequency of Heparin Induced Thrombocytopenia (HIT) in patients undergoing elective cardiac bypass surgeries and to observe the platelets evolution post surgically in these patients.


METHODS
A prospective study was designed and 100 unselected consecutive patients undergoing elective cardiac bypass surgery were enrolled and evaluated. The clinical and laboratory details were noted before and after surgery. Their platelet counts were observed from day 0 (prior to surgery) to day 5 post operatively. Particle gel immunoassay was used to demonstrate the presence of antibodies against heparin-platelet factor 4 complexes.


RESULTS
There were 86 males and 14 females with median age of 59 and 53.5 years respectively. Marked platelet count variation was detected during post operative period in all patients (n=100) ranging from 23 +/- SD 186.73 to 389 +/- 84.12 X 109/L. However, 20 patients showed >50% drop on day 5 and seven of these also showed seroconversion. The clinical scoring for HIT was found to have a good negative predictive value. Thromboembolic complications were not observed in any of our patients.


CONCLUSIONS
HIT is prevalent to a significant extent in patients after cardiac surgery in our clinical setting though it mostly remains undetected and is an under-diagnosed entity.
Ali
Natasha
N
Department of Pathology & Microbiology, The Aga Khan University Hospital, Karachi, Pakistan.
Moiz
Bushra
B
Rehman
Yasmin
Y
Salman
Mohammad
M
Sami
Shahid A
SA
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects*; D001026:Coronary Artery Bypass; D017558:Elective Surgical Procedures; D005260:Female; D006493:Heparin / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010154:Pakistan / Q000453:epidemiology; D010976:Platelet Count; D012307:Risk Factors; D013921:Thrombocytopenia / Q000139:chemically induced / Q000453:epidemiology*
D000925:Anticoagulants; D006493:Heparin