Osteopenia caused by heparin treatment in pregnancy

Pulmonary embolism during and after pregnancy

BACKGROUND

Venous thromboembolic disease is among the most common causes of morbidity and mortality during pregnancy. The clinical evaluation alone is insufficient for the diagnosis of venous thromboembolic disease, and the normal pregnant state makes this evaluation even more challenging.

DIAGNOSIS

Objective testing is the mainstay of diagnosis, including compression ultrasound, impedance plethysmography, ventilation-perfusion scanning, computed tomography scanning, and pulmonary angiography. All of these tests can be safety performed during pregnancy.

TREATMENT

If deep vein thrombosis or pulmonary embolism is diagnosed, anticoagulation should be initiated. Either (unfractionated) heparin or low molecular weight heparin is an acceptable treatment for acute venous thromboembolic disease. Both have risks and benefits, but both can be used safely during pregnancy. Intravenous heparin is the treatment of choice surrounding delivery due to its short half life. Because of the risk of adverse effects on the fetus, warfarin is not generally used during pregnancy. Unstable pulmonary embolism is difficult to treat during pregnancy, as there are minimal data regarding the safety and efficacy of thrombolytic therapy, inferior vena cava filters, and embolectomy during pregnancy. Case reports and case series suggest that thrombolytic therapy may be associated with lower risks of fetal loss than embolectomy.

CONCLUSIONS

Venous thromboembolic disease is a significant cause of morbidity and mortality during pregnancy and the puerperal period. Objective testing is critical to establish the diagnosis and can be safely performed during pregnancy. Anticoagulation with heparin is the mainstay of therapy during the pregnancy, but patients may be transitioned to warfarin after delivery.

Pulmonary embolism and pregnancy

Pulmonary embolism is a significant cause of morbidity and mortality during pregnancy and the puerperium. The spectrum of venous thromboembolism is difficult to diagnose. Objective diagnostic testing is crucial and should not be delayed. Anticoagulation is the mainstay of therapy for deep vein thrombosis and pulmonary embolism. Most of the literature and practice protocols for the treatment of pregnant women are based on data extrapolated from the nonpregnant population, and more research is needed to improve the understanding of the efficacy and safety of testing and therapy in the pregnant population.

Short-term low-dose heparin plus bedrest impairs bone metabolism in pregnant women

OBJECTIVE

To assess the osteoporotic risk of short-term low-dose heparin plus bedrest in pregnancy.

STUDY DESIGN

In a prospective case-control study, 10 pregnant women on bedrest receiving prophylactic unfractionated heparin 10,000 IU per day for 7-46 days pre-study and 28 days per-study were compared with 6 normal pregnant controls of similar maternal and gestational age and 10 nonpregnant women of similar age. Serum ionised calcium, 1,25-dihydroxyvitamin D(3), osteocalcin, and urinary calcium/creatinine ratio were determined three times at 2-week intervals.

RESULTS

1,25-Dihydroxyvitamin D(3) was lower in the treated group than in pregnant controls throughout (P<0.03). Osteocalcin was lower at study start than end in both pregnant groups (P<0.05), and lower in the treated group than in either pregnant (n.s.) or nonpregnant controls (P<0.005). Calcium/creatinine ratio differences were non significant (n.s.).

CONCLUSION

Short-term low-dose heparin plus bedrest suppresses 1,25-dihydroxyvitamin D(3) and osteocalcin levels in pregnancy.

Bone density changes in pregnant women treated with heparin: a prospective, longitudinal study

Heparin plus aspirin significantly improves the live birth rate of women with primary antiphospholipid syndrome. Osteopenia is a major concern of long-term heparin therapy. We studied prospectively the bone mineral density (BMD) changes during pregnancy and the puerperium in 123 women with primary antiphospholipid syndrome treated with low-dose aspirin and subcutaneous low-dose heparin (46 women took unfractionated heparin and 77 took low-molecular-weight heparin). Lumbar spine, neck of femur and forearm BMD were measured, using dual energy X-ray absorptiometry, at 12 weeks gestation, immediately postpartum and 12 weeks postpartum. The mean heparin duration was 27 weeks (range 22-29). During pregnancy, BMD decreased by 3.7% (P < 0.001) at the lumbar spine and by 0.9% (P < 0.05) at the neck of femur with no significant change at the forearm. Lactation was associated with a significant decrease in the lumbar spine and neck of femur BMD. There was no significant difference in BMD changes between the two heparin preparations. No woman suffered a symptomatic fracture. Long-term heparin treatment during pregnancy is associated with a small but significant decrease in BMD at the lumbar spine and neck of femur. This decrease is similar to that previously reported to occur in untreated pregnancies.

Current concepts of anticoagulant therapy in pregnancy

The optimal use of anticoagulants during pregnancy will continue to be controversial until appropriate randomized controlled and prospective trials with adequate sample sizes are completed. The relative low frequency of thromboembolic events, the concerns about maternal and fetal safety of both treatment and withholding treatment, and the reservations about prospectively enrolling pregnant women in treatment trials has sadly dissuaded the appropriate study of this life-threatening condition. North American trials that enroll pregnant women to evaluate the efficacy of LMWH are of preeminent importance owing to their superior bioavailability, ease in dosing, longer half-life, and side effect profile. Similarly, trials evaluating the optimal management of women of childbearing age with valvular disease are critical to reduce the considerable maternal and fetal morbidity and mortality associated with these pregnancies. Such definitive studies will need to be multicenter in design and it is hoped that the National Institutes of Health initiative to enroll pregnant women in clinical trials will at last be realized in the near future.

Cardiopulmonary bypass in patients with heparin-induced thrombocytopenia using Org 10172

BACKGROUND

In patients with heparin-induced thrombocytopenia undergoing cardiac operations, anticoagulation with heparin should be avoided. The low-molecular-weight glycosaminoglycan Orgaran has been used as an alternative, but the overall experience is limited.

METHODS

Two patients with heparin-induced thrombocytopenia underwent cardiopulmonary bypass using Orgaran for anticoagulation. A 30-year-old woman suffered from emboli to her brain through a secondary atrial septal defect, a 14-year-old boy from ischemia of his left leg due to recurrent embolism originating from the mitral valve. In both cases, cardiopulmonary bypass was performed in a routine manner, except for using low-dose Orgaran instead of heparin. Anticoagulation was monitored during cardiopulmonary bypass by measuring Orgaran plasma levels and activated clotting time.

RESULTS

No thromboembolic or bleeding complications occurred during and after atrial septal defect repair and mitral valve replacement, respectively. In the former case, thrombotic material from the inferior vena cava was removed during hypothermic circulatory arrest within the same procedure. Activated clotting time did not correlate with plasma levels of Orgaran.

CONCLUSIONS

Orgaran might be a useful alternative for anticoagulation during extracorporeal circulation. Adequate dosages and measurement of plasma levels are recommended for its use in cardiopulmonary bypass.