SPECT MIBI imaging for cardiac output and index in end stage renal disease

To compare cardiac output (CO) and cardiac index (CI) and left ventricular ejection fraction (LVEF) in end-stage renal disease (ESRD) with a control group using gated single photon emission computed tomography (SPECT)/computed tomography (CT) imaging. Altered cardiovascular function with increased CO secondary to arterio-venous fistulas (AVF) for dialysis has been reported in patients with ESRD. Thirty-two patients (18 with AVF or graft) referred for pre-renal transplant cardiac assessment using SPECT/CT were studied with 2 comparison groups, 42 normal weight (body mass index<30) and 46 obese (body mass index>30) patients. End-stage renal disease patients had overall reduced mean hemoglobin 11.6 mg/dL and elevated mean parathyroid hormone of 396 pg/mL. Gated SPECT using MIBI was performed after Bruce protocol apart from 4 renal patients who underwent cardiac stressing with adenosine. Cardiac output was calculated by product of stroke volume and resting heart rate and CI determined. Mean CI was 2.6 L/min/m(2) for renal disease group compared with 2.2 and 2.3 L/min/m(2) for the normal weight and obese groups, P=0.005 and 0.005 respectively (Wilcoxon's rank test). Cardiac output was increased for the renal group; 4.9 L/min, equal to the obese group but greater than normal weight group at 4.3 L/min. No significant difference in LVEF was seen between the 3 patient groups. No significant difference in CI or output was seen between the renal disease patients with AVF and those without fistulas. Cardiac ouput and CI, assessed using SPECT/CT, are increased in patients with ESRD. This may be independent of the presence of AVF or grafts and other factors such as anemia and hyperparathyroidism may contribute to this high output cardiac function. As LVEF is not increased for these patients, increased heart rate, may also contribute to elevated CO.