Renography before heart transplantation in patients with cardiomyopathy

In patients with ischemic cardiomyopathy (CM), abnormal renograms may resul t not only from circulatory failure (which should reverse after transplanta tion) but also from intrinsic renal disease (which contraindicates heart tr ansplantation). Here, the outcome of heart transplantation was related to p reoperative renograms, and the differentiating and prognostic value of reno graphy was analyzed. Methods: The study population consisted of 50 patients with ischemic CM expecting heart transplantation. Anatomical renal patholo gy was excluded in all patients. Dynamic renal scintigraphy was performed w ith Tc-99m-mercaptoacetyltriglycine. Background-subtracted renograms were i nspected visually and characterized numerically. Mean parenchymal transit t ime (mPTT), renal tracer content at 15 min (RTC15) and retention index (RI) were determined. The parametric renogram values were related to a normal r eference group of 64 patients. The preoperative renograms were matched with the postoperative outcome. Results: Three characteristic types of symmetri cal findings in the kidneys were found: no pathological findings, mildly de layed peak and excretion phase and severely delayed peak and excretion phas e. Pathological renograms were observed in 36 of 50 (72%) patients. The mea n parametric renogram values in ischemic CM were as follows: Group-A (norma l kidney function), mPTT = 142 +/- 26.6 sec, RTC15 = 22.3% +/- 4.6% and RI = 24.7 +/- 11.9; Group B (mild dysfunction), mPTT = 210 +/- 44.0 sec, RTC15 = 42.6% +/- 10.3% and RI = 101.4 +/- 50.5; Group C (severe dysfunction), m PTT = 320 +/- 94.2 sec, RTC15 = 79.6% +/- 15.9% and RI = 347.7 +/- 194.7; a nd reference patients (normal kidney function), mPTT = 137 +/- 31.1 sec, RT C15 = 22.8% +/- 3.8% and RI = 24.6 +/- 7.9. Postoperative serum creatinine levels were <1.5 mg/dl in all Group A patients, between 1.5 and 2.5 mg/dl i n 78% of Group B patients and > 2.5 mg/dl in 75% of Group C patients. Concl usion: Renography revealed abnormal kidney function when structural patholo gy was excluded. The renographic abnormalities in ischemic CM did not refle ct simply the circulatory failure. The numerical grading of renograms allow ed patient stratification, suggestive of possible renal insufficiency after cardiac transplantation and immunosuppressive therapy. With further experi ence, renography may become a useful tool for predicting postoperative outc ome in ischemic CM.