Increased rejection rates in cardiac transplant associated with dexamethasone

BACKGROUND

Peri-operative immunosuppression in cardiac transplantation includes the use of intravenous methylprednisolone. During a national shortage, intravenous dexamethasone was substituted for methylprednisolone at standard equivalencies. Methylprednisolone and dexamethasone are used interchangeably in many clinical settings; however, their equivalency has not been demonstrated.

METHODS

Forty-two consecutive cardiac transplant patients were studied retrospectively. All patients received standard triple immunosuppression. Eighteen patients received dexamethasone and 24 methylprednisolone. Twelve patients were included for comparison after the methylprednisolone shortage resolved. Endomyocardial biopsy (EMB) results graded as > or =1B (ISHLT classification) were considered positive for acute cellular rejection.

RESULTS

More patients who received dexamethasone as induction had cellular rejection (12/17; (70%) vs. 14/33; (42%); p=0.05). Four patients were excluded because of deaths unrelated to cardiac function. The increased rate of rejection seen during dexamethasone substitution declined after reinstitution of methylprednisolone (p=0.05).

CONCLUSIONS

Peri-operative high-dose dexamethasone in cardiac transplants was associated with higher rates of acute cellular rejection. The equivalencies of dexamethasone and methylprednisolone differ from accepted standards when used in pulse doses. Peri-operative use of glucocorticoids may rely on mechanisms that are different from those considered in the standard equivalency measures. Pulse doses of dexamethasone and methylprednisolone in transplantation may not be interchangeable at standard equivalencies.

Nesiritide as Bridge to Multi-Organ Transplantation: A Case Report

Nesiritide, an intravenous form of human B-type natriuretic peptide, has been approved as treatment for patients with acute decompensated heart failure. Due to its action on different receptors, nesiritide has many effects, including vasodilation and natriuresis. Cardiac preload and afterload decrease, leading to an increase in cardiac output through effects on smooth muscle and the kidneys. As a bridge to cardiac transplantation, nesiritide has been used to maintain vasodilation and diuresis without sacrificing kidney function. Our patient, prior to multi-organ transplantation, had a pulmonary capillary wedge pressure of 41 mm Hg on milrinone monotherapy, which decreased slightly with nitroprusside and further decreased to 4 mm Hg after the addition of nesiritide. The patient's measured creatinine clearance level was calculated to be 40 mL/min. When nesiritide therapy was begun, the renal function did not improve, but, as the hemodynamics improved, renal function did not decrease.

Antiviral dosing and efficacy for prophylaxis of cytomegalovirus disease in solid organ transplant recipients

PURPOSE

The implications of the findings from clinical studies and pharmacokinetic analyses of the antiviral agent valganciclovir for dosing of the drug to prevent cytomegalovirus (CMV) disease in solid organ transplant recipients are reviewed.

SUMMARY

Valganciclovir, an oral prodrug of ganciclovir, is as effective as oral ganciclovir for preventing CMV disease, although prophylaxis with either agent may delay CMV disease. Dosage reduction is required for both drugs in patients with renal impairment to prevent high plasma ganciclovir concentrations and toxicity. A valganciclovir dosage of 900 mg/day is required in patients with normal renal function, especially those at high risk for CMV disease, to provide adequate systemic ganciclovir exposure. Some studies suggest that a lower dosage might suffice for patients at a low risk for CMV disease.

CONCLUSION

Valganciclovir dosing should be based on renal function to avoid toxicity.