High treatment-related mortality in cardiac amyloid patients undergoing autologous stem cell transplant.

Dose-intensive chemotherapy with PBSC support was recently reported to be feasible in cardiac amyloidosis with some patients achieving post-transplant improvement in performance status. At our center, 11 patients with symptomatic primary systemic amyloidosis and predominant cardiac involvement confirmed by biopsy or increased wall thickness on echocardiogram were evaluated for high-dose therapy. The average time from diagnosis to referral was 11 months (4-26 months). Of the 11 patients, two were not candidates for high-dose therapy, based on poor performance status. The remaining nine patients proceeded to PBSC collection. Three patients died during the mobilization period: two of rapid atrial fibrillation, and the third secondary to progressive heart failure. Six patients proceeded to transplantation. However, one died of sudden cardiac arrest the day of melphalan administration, one following hypotension related to stem cell infusion, and one of hypotensive shock the day following stem cell infusion. Three patients recovered and left the hospital, but one died of a cardiorespiratory event at home within 6 weeks of discharge. Both surviving patients demonstrate objective improvement. A decision to use high-dose therapy and stem cell support in cardiac amyloidosis must balance the substantial morbidity of the procedure with the potential benefits. Transplant regimens should avoid cardiotoxic agents such as cyclophosphamide and DMSO and patients should receive anti-arrythmic therapy.