Do clinical diagnoses correlate with pathological diagnoses in cardiac transplant patients? The importance of endomyocardial biopsy.

BACKGROUND: Heart transplantation remains the last treatment option for patients with end-stage cardiac disease. Such diseases include ischemic cardiomyopathy, nonischemic cardiomyopathy and other conditions such as arrhythmogenic right ventricular dysplasia, cardiac sarcoidosis and cardiac amyloidosis.
OBJECTIVE: To review the changes that have occurred over time in the etiology of heart disease in patients requiring heart transplantation, and to compare the clinical and histological diagnoses of explanted hearts from patients with progressive cardiac disease.
METHODS: The pathological findings of 296 surgically excised hearts over a 20-year period (January 1987 to July 2006) at one institution were examined. Patients were separated into groups based on year of heart transplantation. The tissue was examined to determine the underlying cardiac pathology leading to congestive heart failure. Patient records were reviewed for preoperative clinical diagnoses and other relevant data, including pretransplant endomyocardial biopsy (EMB) results, information regarding left ventricular assist devices and, finally, evidence of disease recurrence in the grafted heart.
RESULTS: A shift in the underlying etiology was found in patients who underwent heart transplantation from 1992 to 1996, and 1997 to 2001. Between 1987 and 1997, the majority of transplant cases consisted of ischemic cardiomyopathies. From 1997 to 2001, the majority of patients had nonischemic cardiomyopathies, and this trend continued to 2006. A majority of patients with ischemic and hypertrophic cardiomyopathy were diagnosed correctly (96.5% and 82%, respectively) before transplantation. Most patients diagnosed post-transplant with lymphocytic (viral, 15%), hypersensitive/ eosinophilic (25%) and giant cell (100%) myocarditis, arrhythmogenic right ventricle dysplasia (100%), cardiac sarcoidosis (83%) and iron overload toxicity- associated cardiomyopathy (100%) had been misdiagnosed in pretransplantation investigations. Investigations before transplantation did not include an EMB. Of all 296 patients, 51 patients (17%) were misdiagnosed. Excluding the patients with ischemic cardiomyopathy, 46 of 152 patients (30%) were misdiagnosed before transplantation.
CONCLUSIONS: Although cardiac transplantation is a viable treatment option for patients with a variety of cardiac diseases, accurate diagnosis of patients before transplantation remains a priority. Accurate diagnosis of particular diseases (sarcoidosis, myocarditis, iron toxicity-associated cardiomyopathy and others) allows for proper treatment before transplantation, which may slow down disease progression and improve patient outcomes. Furthermore, it is important to accurately diagnose patients with diseases such as sarcoidosis, amyloidosis and particular types of myocarditis because these can readily recur in the grafted heart. The risk for recurrence must be known to practitioners and, most importantly, to the patient. We strongly recommend the use of EMB if a nonischemic cardiomyopathy is suspected, because the results may alter the diagnosis and modify the treatment strategy.