Sudden, unexpected death in cardiac transplant recipients: an autopsy study.

Background: Clinical studies indicate that sudden death (SD) is common after heart transplantation. Autopsy reports of such patients are sparse.
Methods: We performed a retrospective study of clinical and pathologic findings on all autopsied patients who underwent heart transplantation at our institution from January 1984 to July 2002.
Results: There were 74 patients who survived >2 months. Of these, 28 (37.8%) died suddenly. The major causes of sudden death (SD) included acute cellular rejection (ACR) (n = 11, 39.3%) and graft coronary artery disease (GCAD) (n = 11, 39.3%). In 9 patients (32.1%), there was no anatomic cause of death. These deaths, assumed to be primary arrhythmic death (PAD), occurred 5 to 36 months post-transplantation. Pre-transplant diagnosis of idiopathic dilated cardiomyopathy (IDCM) was more common in SD (13 of 28, 46.4% vs 9 of 46, 19.6%; p = 0.014). Hypertrophy was not statistically different in SD vs non-SD (79.4% vs 88.4%; p = 0.38). Coronary thrombosis was also not statistically different in sudden GCAD deaths vs non-sudden GCAD deaths (3 of 11, 27.3% vs 8 of 13, 61.5%; p = 0.09). ACR SD patients had fewer episodes of ACR in biopsies than ACR non-SD patients (93 of 190, 48.9% vs 99 of 159, 63.3%; p = 0.01). Biopsies with Quilty lesions (QL) were more frequent in patients with SD (206 of 461, 44.7% vs 243 of 710, 34.2%; p < 0.001). QL were more common in patients with GCAD (44.4%) and ACR (39.6%) than in patients who died of infection (25.7%; P < 0.001 and p < 0.01, respectively).
Conclusions: SD after cardiac transplantation is common (37.8% of all deaths). ACR, in the first year, and GCAD, afterwards, are associated with SD. PAD occurred in 32.1% of SD cases, 5 to 36 months after transplantation. Pre-transplant diagnoses of IDCM and QL are more common in SD. Surprisingly, cardiac hypertrophy is not increased and coronary thrombosis is not more frequent in patients who died suddenly.