Abstract
The goal of this study was to evaluate the diagnostic accuracy, cost-effectiveness and appropriate use of SPECT myocardial perfusion imaging (SMPI) versus stress echocardiography (SE) in the preoperative evaluation of patients for kidney transplantation. Methods: A single-institution, retrospective study was performed. SMPI was performed with regadenoson and SE predominantly with dobutamine. Findings on subsequent coronary angiography were correlated. Utilizing reimbursements from the Center for Medicare Services (CMS), a cost analysis for SMPI versus SE was modeled. Results: 113 patients underwent imaging (53 SMPI and 60 SE). 100% of SMPI studies were diagnostic compared to only 80% (48/60) in the SE group, and this result was statistically significant (X2 = 7.96, P < 0.01). The most common reason for a non-diagnostic test was not reaching target heart rate. In the SMPI group, 15% (8/53) had ischemia on imaging and all had subsequent coronary angiography which confirmed obstructive coronary lesions. One patient with negative SMPI had subsequent angiogram that was negative. In the SE group, 5% (3/60) had ischemia on imaging and two had subsequent angiography, which were negative. Three of 12 patients with non-diagnostic exams underwent further testing. One patient had a follow-up positive SMPI but no subsequent coronary angiography. The other two patients underwent coronary angiography that were negative. Of the 45 negative SE, six (13%) had angiography with positive result for obstructive coronary artery disease in 3/6. For modeling of cost analysis, CMS rates of $1,173 and $1,521 were utilized for SMPI and SE respectively. The model assumes that all non-diagnostic imaging would be referred for further stress testing (i.e. non-diagnostic SE would be referred for SMPI). This model estimates that initial non-invasive testing with SE versus SMPI results in 50% greater cost. Conclusion: For pre-operative evaluation of kidney transplantation, SMPI is more often diagnostic than SE. A cost model estimates that initial non-invasive diagnostic testing with SE would result in approximately 50% greater cost compared to SMPI. Our data also suggests that SMPI has greater diagnostic accuracy than SE. Therefore, this single institution experience supports SMPI as the more appropriate test.