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Chapter 132 Thrombocytopenia Caused by Platelet Destruction, Hypersplenism, or Hemodilution 1971

The pathogenesis and clinical significance of the hemostatic defect helps to explain why the postsurgery platelet count usually continues
in these patients remain uncertain, but the explanation is probably to decline over the next 1–3 days, with the postoperative nadir (lowest
multifactorial. Studies have described transient, intrinsic defects in platelet count value) usually occurring at a median of postoperative
2
platelet function. These defects include decreased in vitro platelet day 2, with a range between postoperative days 1–4 (Fig. 132.7).
aggregation, decreased platelet surface membrane proteins, selective Subsequently, there is a rise in the platelet count that peaks at
depletion of platelet α-granules, and evidence of in vivo platelet approximately day 14 at levels often 2–3 times the patient’s preopera-
activation and platelet vesiculation. The platelet dysfunction in heart tive baseline before it returns to baseline over the next 2 weeks (≈day
surgery is also attributable to an extrinsic platelet defect resulting from 28). As described earlier in this chapter (see Fig. 132.1), these platelet
thrombin inhibition by the high doses of heparin. Furthermore, an count changes reflect thrombopoietin physiology.
important role for hyperfibrinolysis in the pathogenesis of bleeding
is shown by elevated D-dimer levels in bleeding patients, as well as
the efficacy of antifibrinolytic agents in the prevention and treatment REFERENCES
of heart surgery–associated bleeding. Other factors in some patients
include residual heparin effect after bypass (including heparin 1. Arnold DM, Warkentin TE: Thrombocytopenia and thrombocytosis. In
rebound) and preoperative use of aspirin and/or clopidogrel. Treat- Wilson WC, Grande CM, Hoyt DB, editors: Trauma: Critical care, (vol
ment of platelet dysfunction after cardiopulmonary bypass is discussed 2). New York, 2007, Informa Healthcare USA, p 983.
in Chapter 159. 2. Greinacher A, Warkentin TE: Acquired non-immune thrombocytopenia.
In Marder VJ, Aird WC, Bennett JS, editors: Hemostasis and thrombosis:
THROMBOCYTOPENIA ASSOCIATED WITH Basic principles and clinical practice, ed 6, Philadelphia, 2013, Lippincott
Williams & Wilkins, p 796.
CARDIOVASCULAR DISEASE 3. Warkentin TE, Kelton JG: Temporal aspects of heparin-induced throm-
bocytopenia. N Engl J Med 344:1286, 2001.
Congenital Cyanotic Heart Disease 4. Siegel DM, Cook RJ, Warkentin TE: Acute hepatic necrosis and ischemic
limb necrosis. N Engl J Med 367:879, 2012.
Thrombocytopenia caused by a decrease in platelet life span occurs 5. Warkentin TE: Ischemic limb gangrene with pulses. N Engl J Med
in some patients with severe cyanotic congenital heart disease and is 373:642, 2015.
approximately related to the severity of the polycythemia. Bleeding 6. Eskazan AE, Buyuktas D, Soysal T: Postoperative thrombotic thrombo-
occurs in a few patients and can be related to platelet function defects, cytopenic purpura. Surg Today 45:8, 2015.
coagulopathy, or hyperfibrinolysis. Reducing the hematocrit by 7. Harji DP, Jaunoo SS, Mistry P, et al: Immunoprophylaxis in asplenic
phlebotomy sometimes helps to correct the hemostatic defects. patients. Int J Surg 7:421, 2009.
8. Aster RH, Bougie DW: Drug-induced immune thrombocytopenia. N
Engl J Med 357:580, 2007.
Valvular Heart Disease 9. Warkentin TE: Drug-induced immune-mediated thrombocytopenia—
from purpura to thrombosis. N Engl J Med 356:891, 2007.
Increased platelet turnover is common in valvular heart disease, and 10. Arnold DM, Nazi I, Warkentin TE, et al: Approach to the diagnosis and
some patients have mild thrombocytopenia. The pathogenesis of the management of drug-induced immune thrombocytopenia. Transfus Med
platelet consumption is not well understood, but the defect could be Rev 27:137, 2013.
related to increased platelet–von Willebrand factor (vWF) interac- 11. George JN, Nester CM: Syndromes of thrombotic microangiopathy. N
tions at high shear. Indeed, high-molecular-weight multimers of vWF Engl J Med 371:654, 2014.
are reduced in some of these patients, which explains why bleeding 12. George JN, Raskob GE, Shah SR, et al: Drug-induced thrombocyto-
from gastrointestinal angiodysplasia in patients with aortic stenosis penia: a systematic review of published case reports. Ann Intern Med
30
(Heyde syndrome) typically resolves after aortic valve replacement. 129:886, 1988.
Thrombocytopenia secondary to consumptive coagulopathy can be 13. Reese JA, Li X, Hauben M, et al: Identifying drugs that cause acute
seen in intracardiac thrombosis associated with valvular heart disease. thrombocytopenia: an analysis using 3 distinct methods. Blood 116:2127,
2010.
14. Arnold DM, Kukaswadia S, Nazi I, et al: A systematic evaluation of labo-
Pulmonary Vascular Disorders ratory testing for drug-induced thrombocytopenia. J Thromb Haemost
11:169, 2013.
Disorders characterized by pulmonary hypertension can be accompa- 15. Von Drygalski A, Curtis BR, Bougie DW, et al: Vancomycin induced
nied by thrombocytopenia, the pathogenesis of which is poorly immune thrombocytopenia. N Engl J Med 356:904, 2007.
defined. Thrombocytopenia can occur in association with pulmonary 16. Bougie DW, Wilker PR, Aster RH: Patients with quinine-induced
embolism, possibly as a result of DIC. When evaluating such patients, immune thrombocytopenia have both “drug-dependent” and “drug-
the clinician should inquire about current or recent heparin exposure specific” antibodies. Blood 108:922, 2006.
because HIT and pulmonary embolism are strongly associated. 17. Liu X, Sahud MA: Glycoprotein IIb/IIIa complex is the target in
mirtazapine-induced immune thrombocytopenia. Blood Cell Mol Dis
30:241, 2003.
HEMODILUTION AND PLATELET CONSUMPTION 18. Stuhec M, Alisky J, Malesic I: Mirtazapine associated with drug-related
AFTER SURGERY thrombocytopenia: a case report. J Clin Psychopharmacol 34:662,
2014.
Platelet count declines of 30% to 70% occur universally after 19. Aster RH, Curtis BR, McFarland JG, et al: Drug-induced immune
major surgery and reflect the combined effects of hemodilution thrombocytopenia: pathogenesis, diagnosis, and management. J Thromb
and increased platelet consumption. Such hemodilution-associated Haemost 7:911, 2009.
thrombocytopenia is especially prominent after cardiac surgery and is 20. Bougie DW, Nayak D, Boylan B, et al: Drug-dependent clearance of
proportional to the amount of fluids (crystalloid, colloid, blood prod- human platelets in the NOD/scid mouse by antibodies from patients
ucts) administered. The platelet count fall is abrupt and is evident a with drug-induced immune thrombocytopenia. Blood 116:3033,
few hours after surgery. Dilutional coagulopathy also occurs, which 2010.
is responsible for the minor to moderate increases in coagulation test 21. Aster RH, Curtis BR, Bougie DW, et al: Thrombocytopenia associ-
results that occur transiently after surgery. ated with the use of GPIIb/IIIa inhibitors: Position paper of the
Perioperative hemodilution is also usually accompanied by ISTH working group on thrombocytopenia and GPIIb/IIIa inhibitors.
increased platelet consumption related to the effects of surgery. This J Thromb Haemost 4:678, 2006.