QTc prolongation in apheresis platelet donors.
BACKGROUND
Citrate infusion during apheresis procedures can cause lowering of the plasma ionized calcium leading to prolongation of the QT interval and hypotension. At the myocardial level, QTc measurement is a sensitive marker of subphysiologic calcium values caused by citrate toxicity.


METHODS
Seventy-six regular platelet donors were recruited into this study. QTc intervals were measured continuously for 3 minutes at four different points during the apheresis procedures. The blood pressure was recorded every 5 minutes throughout the procedure.


RESULTS
The baseline QTc value for men was 406.5 +/- 13.1 milliseconds(1/2) and for women was 417.6 +/- 13.3 milliseconds(1/2) (p = 0.0016). OTc prolongation occurred in all procedures in all donors. Maximum recorded values were significantly higher in women than in men (450.8 +/- 20.8 vs. 424.8 +/- 14.3 ms(1/2); p = 0.0025). All QTc values returned to baseline by 15 minutes after the procedure. Changes in blood pressure were minimal and no donor experienced severe symptoms.


CONCLUSIONS
QTc prolongation always occurs during plateletpheresis. This prolongation is greater in women than in men. This study indicates that it may be advisable to assess donors for family or personal history of syncope and family history of sudden death to exclude those at increased risk of arrhythmias because of asymptomatic carriage of a long-QT gene. In addition baseline QTc measurement is a simple noninvasive procedure that could be applied to further studies with a view to enhancing donor safety in apheresis.
Laspina
Stefan J
SJ
Irish Blood Transfusion Service, National Blood Center, Dublin. stefan.laspina@ibts.ie
Browne
Martin A
MA
McSweeney
Ellen N
EN
Lawlor
Jo
J
Whelan
Denise M
DM
Kinsella
Anthony L
AL
Murphy
William G
WG
D000328:Adult; D001782:Blood Donors; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000097:blood; D019343:Citric Acid / Q000633:toxicity; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006801:Humans; D007022:Hypotension / Q000139:chemically induced; D008133:Long QT Syndrome / Q000097:blood / Q000139:chemically induced*; D008297:Male; D008875:Middle Aged; D010983:Plateletpheresis; D012737:Sex Factors
D019343:Citric Acid; D002118:Calcium