Kidney function in heart-lung transplant recipients: the effect of low-dosage cyclosporine therapy

The indices of kidney function of all discharged heart-lung transplant survivors were examined before and after the introduction of a triple-drug immunosuppressive regimen comprised of low dosages of cyclosporine (to maintain a trough serum level of 75 to 100 ng/ml by radioimmunoassay), azathioprine (1 to 1.5 mg/kg/day), and prednisone. A comparison of survivors treated with either high dosages of cyclosporine (n = 19) or low dosages of cyclosporine (n = 8) revealed a lower early creatinine level postoperatively (1.84 versus 0.96 mg/dl), a higher creatinine clearance (46.33 versus 62.47 ml/min), and a lower cyclosporine level (337.96 versus 204.30 ng/ml) in the latter group. The findings from the outpatient period were similar to the above, and all findings were statistically significant (p less than or equal to 0.05). Another comparison of a subgroup of survivors (n = 11) before and after conversion to the low dosage cyclosporine triple-drug regimen demonstrated no significant difference in kidney function for nine patients and equivocal evidence of improvement in the other two patients for creatinine levels and creatinine clearance. Overall, despite the lower cyclosporine dosage used, we have not encountered an increased prevalence of acute heart or lung rejection. We conclude that early implementation of low dosages of cyclosporine, as part of a triple-drug immunosuppression regimen, is associated with preservation of kidney function while maintaining adequate immunosuppression. Patients with chronic azotemia from long-term cyclosporine therapy may still reap some benefit from this regimen.