Einfluss des Immunsuppressiva-induzierten Hypogonadismus auf den Knochenmetabolismus nach Herztransplantation

Bone Loss after Heart Transplant: Effect of Alendronate, Etidronate, Calcitonin, and Calcium plus Vitamin D3

Objective

To compare the effects of calcitonin, etidronate, and alendronate in preventing bone loss during the first 2 years after heart transplant.

Methods

A total of 222 heart transplant recipients (mean [SD] age, 52.4 [10] years, 85% male) were evaluated. Patients with normal bone mineral density (reference group, n = 102) received 1000 mg/d calcium plus 800 IU/d vitamin D3. The rest were assigned to 200 IU/d of calcitonin (n = 42), 400 mg/d etidronate orally for 14 days quarterly (n = 33), or 10 mg/d alendronate (n = 45). All patients received calcium and vitamin D. Bone mineral density was assessed by dual-energy x-ray absorptiometry in the lumbar spine, the entire femur, and the femoral neck at baseline and 6, 12, and 24 months after transplant.

Results

At 2 years after transplant, bone mineral density in the lumbar spine had decreased in the reference group (−3.07%), calcitonin group (−0.93%), and etidronate group (−1.87%) but not in the alendronate group (+4.9%; P < .001). After 2 years, bone mineral density in the entire femur decreased in all groups (−3.2% in the reference group, −3.6% in the calcitonin group, −4.6% in the etidronate group, and −0.5% in the alendronate group) but bone loss was significantly lower in the alendronate group ( P < .001). Bone mineral density in the femoral neck also decreased in all groups. The incidence of vertebral fractures did not differ among groups. Adverse events were similar between groups.

Conclusions

Alendronate therapy in heart transplant recipients was associated with a significant increase in bone mineral density in the lumbar spine and less bone loss at the hip.

Markers of bone metabolism in congestive heart failure

Congestive heart failure (CHF) is a chronic disease, whose incidence is especially growing in the subpopulation of elderly people. CHF is characterized by dyspnea and fatigue at rest or with exertion, ankle swelling and pulmonary edema. Cardiac transplantation is the ultimate therapeutic measure in patients with end-stage CHF. Some risk factors associated with CHF such as low mobility, renal failure, and prescription of specific drugs may predispose patients to develop osteoporosis. This review article gives an overview about markers of bone metabolism in CHF patients as well as in heart transplant recipients. At first, the physiology of bone metabolism is summarized. Then, a short description of different bone formation and resorption markers is presented. They can be used to characterize actual bone metabolism and can be helpful to explain possible mechanisms of bone loss. Regarding pre-transplant CHF patients, available data indicate that the disturbances in bone metabolism are only subtle. Heart transplant recipients, however, are at increased risk for osteoporotic bone loss due to the use of immunosuppressive agents such as corticosteroids and calcineurin inhibitors. Preventive strategies are able to normalize bone metabolism and to attenuate the high bone loss during the first year after heart transplantation.