Abstract
A clinical study was started in order to examine the suitability of the Thrombostat
(in vitro bleeding test) (IVBT) as a diagnostic tool to prevent perioperative bleeding
due to aspirin (ASA) and/or platelet function disorders of other origins. This report
is based on preliminary data. Eighty three patients who had ingested ASA in the last
two weeks and/or with a history of bleeding and/or documented hemorrhagic disorders
requiring distinct urological operations, were included in the study. In all patients
the IVBT with CaCl2 , in addition to common coagulation tests, were performed. Thirteen patients stopped
ASA ingestion until IVBT became normal and did not show any increased bleeding tendency.
The residual patients were classified by the various operations. The following operation
groups were formed: Male genitals (n = 11), inguinal/suprapubic operations (n = 7),
transurethral tumor resections of the bladder (TURB) (n = 17), transurethral prostate
resection (TURP) (n = 12), tumor nephrectomy (n = 8), radical prostatectomy (n = 9).
Thirty six patients with a history of ASA use, but normal IVBT, served as control
group (C). Thirty one patients with a history of ASA ingestion had normal in vivo
bleeding times (BT) and abnormal IVBT with CaCl2 (A). Seven patients had a bleeding history and/or documented hemorrhagic disorders
(B). None of the patients (A) with abnormal IVBT but normal BT displayed clinically
relevant bleeding. However, the blood loss was somewhat higher compared to the controls
(C), especially in patients with TURB and radical prostatectomy (not significant).
The only real bleeding complication occurred in an ASA patient (TURB), who was subjected
to surgery by error. Anesthesia had already started, when abnormality of BT (>15 min)
and IVBT (m“infinite ”) were measured. Operative revision was necessary and revealed
that the blood loss (>3 L) was based on diffuse microvascular bleeding. The majority
of the patients with a bleeding history and/or documented hemorrhagic disorders (B)
showed an increased bleeding tendency, which could be managed without relevant blood
loss, except in two patients, one with factor XIII deficiency (25%) and ASA intake,
and the other with undetected mild congenital platelet disorder (storage pool disease?).
The IVBT proved suitable as screening test for platelet function disorders. Major
bleeding complications could be prevented by its use. A history of low-dose ASA ingestion
without prolongation of BT, but abnormal IVBT, also seemed to increase the bleeding
tendency; however, the clinical relevance has to be demonstrated by an extended clinical
study.
Keywords
bleeding time - aspirin - urologic surgery - Thrombostat - acetylsalicylic acid
