Extremely Shortened Activated Partial Thromboplastin Times

Belliveau, Robert R.

doi:10.1001/jama.1980.03300480012006

Cited by 4 publications

(7 citation statements)

References 2 publications

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“…These cases are important because they provide data supporting the 2 seemingly contradictory observation that a short aPTT is related to hypercoagulablestate (2,4) as well as bleeding episodes. (5,6) We can only speculate on the mechanism of short aPTTs in our patients with a diagnosis of bleeding, but it seem reasonable to postulate that abnormally short aPTT with an increase in thrombin generation might be physiologic response of coagulation system to an abnormal blood loss. as suggested by Bellivbeau.…”

Section: Discussionmentioning

confidence: 83%

“…Such a relationship had been described twice. (5,6) These findings seemed to argue against the value of a short aPTT as a possible indicator for a hypercoaguilable state. it is therefore exciting for us to find that 4(36%) of 11 patients with a short aPTT and bleeding episode during hospitalization also had thrombotic events during 18 months proximate to blood collection.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast with bleeding disorders and prolonged aPTTs, very little work exists on the possible meaning of aPTTs below lower limit of a reference or normal range. One large prospective trial evaluating this question concludes that short aPTTs probably representing increase in procoagulant potential (2) ; however this conclusion has been disputed (5) .…”

Section: Discussionmentioning

confidence: 99%

“…(3, 4) These findings have been disputed, and there is some suggestion in the literature that short aPTTs occur during bleeding episodes. (5,6) Nowadays, molecular markers of activation processes in the coagulation and fibrinolytic system have become widely available for use in the specialized clinical laboratory. Prothrombin fragment F1+2 is cleaved from prothrombin on activation by factor Xa in amounts equimolar to the thrombin generated.…”

mentioning

confidence: 99%

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Increased Risk of Thromboembolism as a Result of High Thrombin Production Is Associated With Short Activated Partial Thromboplastin Time in Cancer Patients on and After Chemotherapy: A Prospective Study in a Tertiary Care Hospital

Dhar¹,

Ray²,

Burman³

et al. 2014

jemds

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Increased Risk of Thromboembolism as a Result of High Thrombin Production Is Associated With Short Activated Partial Thromboplastin Time in Cancer Patients on and After Chemotherapy: A Prospective Study in a Tertiary Care Hospital

Dhar¹,

Ray²,

Burman³

et al. 2014

jemds

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“…McKenna and associates 7 suggested that short APTTs, particularly when found on repeat testing, carried a significant risk of subsequent thromboembolism and prophylactic anticoagulation was possibly indicated. By contrast, Belliveau 8 observed that a short APTT was associated with a higher risk of bleeding and that an extremely short APTT should alert the physician to the possibility of occult gastrointestinal or genitourinary tract bleeding. No mechanism for the association of a short APTT and a bleeding risk was proposed, however.…”

Section: Discussionmentioning

confidence: 92%

Artifactual Prolongation of the Activated Partial Thromboplastin Time Mimicking a Coagulopathy:A Lesson Relearned

et al. 1993

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A markedly prolonged activated partial thromboplastin time (APTT) was observed in a 61-year-old woman with bruising and a decreasing hematocrit. Coagulation laboratory evaluation was sought to determine the cause of the prolonged APTT and bleeding. Evaluation demonstrated that, rather than identifying a coagulopathy, the APTT prolongation was most likely artifactual. The APTT was actually very short. With a combination of a relatively strong activating APTT reagent (Dade Actin; Dade, Miami, FL) and a fixed lag phase in the automated The activated partial thromboplastin time (APTT) is a routine and widely used coagulation assay. Although perhaps most commonly used as a routine admission laboratory or preoperative screening test, its greatest utility is in the detection of hemostatic defects in patients with bleeding.1 The APTT is now performed almost exclusively on automated coagulation instruments, rather than by a manually operated technique, such as a fibrometer. Inherent in the program of most automated coagulation instruments is a period of up to 20 seconds after addition of the activator and calcium before optical density measurements are read to avoid interpreting turbulence as evidence of clot formation. Ordinarily the APTTs of patients are longer than this lag phase. However, a strong activating APTT reagent may have a normal range of 20-25 seconds or even shorter. Short APTTs may be observed in acutely ill patients because of marked elevations of Factor VIII:C or fibrinogen 2 and in patients with disseminated intravascular coagulation caused by the presence of activated clotting factors.3 The use of this combination of an instrument with a long lag phase and a strong activator to evaluate a patient with a short APTT may result in an APTT shorter than the lag phase. When this happens, the instrument only begins recording at the end of the lag phase (ie, after the clot has formed) and records no change in light transmission during the entire recording period, suggesting that no clot has formed. This type of error can be particularly misleading in the evaluation of a patient with active bleeding. CASE REPORTA 61 -year-old woman with chronic rheumatoid arthritis and pulmonary fibrosis was seen for evaluation of ecchymoses, which developed spontaneously over her left upper chest during a 2-day period. Laboratory studies showed a normal prothrombin time and a markedly prolonged APTT (Table 1). Her hematocrit, which during the past year had been in the range of 30-35%, was decreased to 25%. She was admitted to the hospital for evaluation. Her medications on admission included methylprednisolone, nizatidine, verapamil, triamterene, hydrochlorothiazide, ciprofloxacin, albuterol by inhaler, and 4 L of oxygen by nasal cannula. Examination showed a well-demarcated dark ecchymosis over her left upper chest extending into the axilla. No hematoma was palpable. Multiple smaller (< 5 cm) ecchymoses were found on the arms and legs. Her stools tested negatively for occult blood. The patient received four units of fresh-fr...

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