BHIT in Pregnancy

HIT has complicated UFH treatment given for venous thromboembolism complicating pregnancy (Van der Weyden et al., 1983; Meytes et al., 1986; Copplestone and Oscier, 1987; Greinacher et al., 1992) or the postpartum period (Calhoun and Hesser, 1987). HIT seems to be rare in this patient population; no pregnant patients have been diagnosed with HIT over a 25-yr period in Hamilton. Plasma glycosaminoglycans are increased during pregnancy (Andrew et al., 1992), which could contribute to lower frequency or pathogenicity of HIT antibodies. HIT antibodies cross the placenta (Greinacher et al., 1993), so it is at least theoretically possible that a heparin-treated newborn delivered from a mother with acute HIT could develop this drug reaction.

Pregnant patients with HIT have developed unusual events, such as cerebral dural sinus thrombosis (Van der Weyden et al., 1983; Calhoun and Hesser, 1987). Treatment options for pregnant patients with life-threatening thrombosis include danaparoid or fondaparinux as these drugs do not cross the placenta (see Chapters 12, 13 and 17). The more benign syndrome of heparin-induced skin

TABLE 6 Cardiological and Neurological Complications of HIT

Cardiological complications

Myocardial infarction (Rhodes et al., 1973; Van der Weyden et al., 1983)

Occlusion of saphenous vein grafts postcoronary artery bypass surgery3

Intra-atrial thrombus (left and right" heart chambers) (Scheffold et al., 1995; Olbricht et al., 1998)

Intraventricular thrombus (left and rightb heart chambers) (Commeau et al., 1986; Dion et al.,

1989; Vignon etal., 1996) Prosthetic valve thrombosis (Bernasconi et al., 1988; Vazquez-Jimenez et al., 1999) Right heart failure secondary to massive pulmonary embolism

Cardiac arrest postintravenous heparin bolus (Ansell et al., 1986; Platell and Tan, 1986; Hewitt etal., 1998) Neurological complications Stroke syndrome In situ thrombosis

Progressive stroke in patients receiving heparin for treatment of stroke (Ramirez-Lassepas etal., 1984) Cardiac embolization (Scheffold et al., 1995)

Cerebral vein (dural venous sinus) thrombosis (Van der Weyden et al., 1983; Kyritsis et al., 1990; Meyer-Lindenberg et al., 1997; Warkentin and Bernstein, 2003); complicating pregnancy (Calhoun and Hesser, 1987) Amaurosis fugax (Theuerkauf et al., 2000) Ischemic lumbosacral plexopathy (Jain, 1986)

Paraplegia, transient (Maurin et al., 1991) or permanent (Feng et al., 1993), associated with distal aortic thrombosis Transient global amnesia (Warkentin et al., 1994) Headachec aThrombosis preferentially affects saphenous vein grafts rather than internal mammary artery grafts (Liu et al., 2002; Ayala et al., 2002).

bAlthough adherent thrombi that likely developed in situ have been reported (Dion et al., 1989), emboli originating from limb veins can explain right-sided intra-atrial or intraventricular clots.

cHeadache as a feature of HIT is suggested by (i) its occurrence in patients with acute systemic reactions postheparin bolus and (ii) its concurrence with onset of thrombocytopenia in several patients who developed HIT in a clinical trial (unpublished observations of the author). Abbreviation: HIT, heparin-induced thrombocytopenia.

lesions without thrombocytopenia has also been reported in pregnant patients (Drouet et al., 1992). Danaparoid was reported to be effective in a patient who developed LMWH-induced skin lesions (de Saint-Blanquat et al., 2000).

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