Question

a 70-year-old male was admitted for dizziness and labored breathing. he was treated for congestive heart failure. he is a heavy smoker and the only medication he takes is aspirin.

CBC. WBC: 16.5. RBC: 6.5. HGB: 20. HCT: 60.6. PLT: 695,000

PT: 22sec. APTT: 85sec. PFA: abnormal

a. does the patient have an abnormality in the common pathway? why or why not?

b. what additional laboratory procedures are indicated?

c. explain the PFA time results?

d. what hematologic disorder does the patient have?

(this is the only information given. )

Answer 1

Introduction

Congestive heart failure (CHF) is a chronic progressive condition that affects the pumping system of heart in which the heart can't pump effectively to meet the needs of the body.

Content

a. The common pathway consists of a group of events that leads from the formation of activated factor X to the formation of active thrombin, the cleavage of fibrinogen by thrombin, and the formation of cleaved fibrin into a stable multimeric, cross-linked complex.The common pathway consists of factors I, II, V, VIII, X. Prothrombin time(PT) is a laboratory value that is used to assess the common pathway, i.e. coagulation factors I, II, V, VIII and X. The normal value of PT is 11 to 13.5 seconds.

For this patient the common pathway is affected. Because his PT is 22seconds. That means PT is high. It is evident from the question that the patient is taking medication Aspirin. Aspirin has an antiplatelet property and it prevent the platelets from clumbing together to form clots. It is contributing to the high levels of PT. Elevated PT prevent coagulation and thus focus to deficiency in the common pathway.

b. Because of increased PT we can do other coagulation testes

- bleeding time (BT)

- activated partial thromboplastin time (aPTT)

- thrombin time (TT)

- INR

Because of increased platelet we can do JAK2, a blood test for a specific gene to diagnose thrombocytosis.

c. Platelet function assay time results

  The PFA test is a new laboratory screening test of platelet function that measures both platelet adhesion and aggregation. It is a rapid, accurate screening test of platelet function.The PFA test is performed with a laboratory analyzer termed the PFA -100.

The PFA test result is dependent on platelet function, plasma von Willebrand Factor level, platelet number, and (to some extent) the hematocrit. The PFA test is initially performed with the Col/Epi membrane. The Col/ADP test is automatically performed one.A normal Col/Epi closure time (<183 seconds) indicates that there is no significant platelet function defects are present. If the Col/Epi closure time is prolonged (>183 seconds), the Col/ADP test is automatically performed. If the Col/ADP result is normal (<122 seconds), probably it is an aspirin-induced platelet dysfunction. Prolongation of both test results (Col/Epi >183 seconds, Col/ADP >122 seconds) may indicates,

-Anemia (hematocrit <0.28)

-Thrombocytopenia (platelet count < 100 x 109/L)

-A significant platelet function defect other than aspirin

Long-term aspirin therapy may modestly prolong the Col/ADP. Once anemia and thrombocytopenia have been excluded, further investigations should started to find von Willebrand disease and inherited/acquired platelet dysfunction such as renal failure storage pool disease, release defect, Bernard-Soulier disease, and Glanzmann thromboasthenia etc.

d. Thrombocytosis