HEART TRANSPLANTATION-ASSOCIATED PERIOPERATIVE ISCHEMIC MYOCARDIAL INJURY - MORPHOLOGICAL FEATURES AND CLINICAL-SIGNIFICANCE

Background The frequency and clinical significance of perioperative is chemic myocardial injury (PIMI) after heart transplantation and the di agnostic features distinguishing PIMI from rejection are not well defi ned. Methods and Results We evaluated PIMI in the first four weekly en domyocardial biopsies and/or autopsy myocardium from 140 consecutive o rthotopic heart transplantation recipients (1984 to 1991) by grading t he severity of coagulative myocyte necrosis (CMN) as absent, 0; mild-f ocal, 1; moderate-multifocal, 2; or severe-confluent, 3, and determini ng the evolution of morphological features of its healing. CMN (often with contraction bands) was noted in 124 patients (89%); 24 patients ( 17%) had grade 3 CMN, of which 4 died within 30 days of transplantatio n. Nevertheless, at 1 year after surgery, survival was similar in pati ents with and without severe injury. Increased cold ischemic time but neither donor age nor intensity of inotropic support correlated with m ore severe early ischemic injury, PIMI inflammation was characterized by a predominantly polymorphonuclear/histiocytic infiltrate that conta ined lymphocytes and plasma cells, expanding the interstitium but not encroaching upon and separable from adjacent viable myocytes. Histolog ical features of PIMI developed and resolved more slowly than those of typical myocardial infarct necrosis in nonimmunosuppressed patients; at 4 weeks, CMN persisted in 20% of patients and residual healing in n early half. Diagnostic rejection was observed concurrently with PIMI i n 54 of 533 biopsies (10%). Conclusions Diagnosed by conventional hist ological criteria, PIMI is prevalent early after heart transplantation and has a protracted healing phase that can mimic or coexist with rej ection. Extensive PIMI has deleterious impact on short-term survival, but the long-term impact of PIMI remains to be established.