Predictive Value of Stress Myocardial Perfusion Imaging in Liver Transplant Candidates Charles J. Davidson, MD, Mihai Gheorghiade, MD, James D. Flaherty, MD, Michael D. Elliot, MD, Srinivas P. Reddy, MD, Norman C. Wang, MD, Sri A. Sundaram, MD, Steven L. Flamm, MD, Andres T. Blei, MD, Michael I. Abecassis, MD, and Robert O. Bonow, MD D ue to the significant potential for perioperative and late cardiovascular complications, screening for coronary artery disease (CAD) has become com- mon in candidates for orthotopic liver transplant (OLT). 1–3 However, the optimal screening method in this population has not been established. Studies as- sessing the utility of dobutamine stress echocardiog- raphy (DSE) and single-photon emission computed tomographic (SPECT) technetium-99m sestamibi im- aging in OLT candidates have been inconclusive. 2–5 Diagnostic coronary angiography has been advocated for candidates with several cardiac risk factors. 1 How- ever, the American College of Cardiology/American Heart Association guidelines consider a class III indi- cation for coronary angiography in patients awaiting liver transplant when they are 40 years of age, unless noninvasive testing reveals high risk for ad- verse outcome. 6 We compared the sensitivity and specificity of single-photon emission computed to- mography with coronary angiography for detection of CAD in a group of OLT candidates. ••• Between September 1990 to August 2000, 394 OLT candidates were evaluated at Northwestern Me- morial Hospital. Of these, 94 patients were referred by a single cardiologist (MG) for coronary angiography after SPECT stress imaging regardless of the outcome of the stress test. There was at least 1 cardiovascular risk factor (advanced age, tobacco use, diabetes mel- litus, hypertension, a family history of CAD or hyper- cholesterolemia) in 89 of 94 (95%). The primary study group consisted of the 83 patients without a previous history of CAD. Independent observers who were blinded to the results of both the invasive or noninva- sive studies reviewed single-photon emission com- puted tomography and coronary angiography. Four- teen underwent single-photon emission computed to- mography and 4 underwent angiography, performed at outside institutions. The imaging protocol used by 83% of the study population undergoing pharmacologic SPECT imag- ing at Northwestern Memorial Hospital is described. Continuous electrocardiographic monitoring was per- formed during the infusion and recovery periods. Se- rial blood pressure measurements and 12-lead electro- cardiograms were obtained during the stress test and recovery period. The initial study involved the intra- venous injection of thallium-201 (3.0 mCi) at rest, followed by imaging 5 to 10 minutes later. In patients who underwent stress testing before July 1997, a stan- dard dipyridamole technique was used. Technetium- 99m sestamibi or tetrofosmin was administered 3 min- utes after completion of the 4-minute infusion (140 g/kg/min). After July 1997, a routine 6-minute aden- osine infusion (140 g/kg/min) was used, with sesta- mibi or tetrofosmin injection at the end of the third minute of infusion. Standard SPECT images were acquired 60 minutes after injection. Perfusion imaging was performed using a dual- detector gamma camera (ADAC Vertex, Malipitas, California), with 64 projections each for 25 seconds with a circular 180° orbit. A Butterworth filter was applied for image reconstruction. After reorientation, the perfusion data were displayed in the standard American College of Cardiology format for visual interpretation. A single blinded reader performed the image interpretation. All scans were graded qualita- tively: any defect seen, regardless of size (small, me- dium, or large), severity (mild, moderate, or severe), or reversibility (fixed or reversible) was interpreted as positive. A semiquantitative scoring system using a previ- ously described 20-segment model was also used on the 69 scans recorded at Northwestern Memorial Hos- pital. 7 Segments were scored from 0 to 4 (0 = normal tracer activity, 4 = no tracer activity). These scores were added to produce a summed stress, summed rest, and summed difference score. Summed stress and rest scores were obtained by adding the scores of the 20 segments of the stress and rest images, respectively. The summed difference score was calculated by sub- tracting the summed rest score from the summed stress score. The summed difference score is an index of jeopardized myocardium and a score 2 correlates with a reversible defect abnormality. 7 Cardiac catheterization was performed using stan- dard Judkin’s technique with multiple views. Signifi- cant CAD was defined as a visual diameter stenosis of 70% in the worst view. All angiograms were graded by an independent observer blinded to the SPECT results and patient outcomes. Viral infections accounted for 42 (51%) and alco- hol for 21 (25%) patients. The median age was 56 years (range 35 to 73); 48 (58%) were men. Cardiac From the Department of Medicine, Division of Cardiology, Division of Gastroenterology, and Department of Surgery, Division of Transplan- tation, Northwestern University Medical School, Chicago, Illinois. Dr. Davidson’s address is: Northwestern Memorial Hospital, Feinberg Pavilion, #8-526, 251 E. Huron Street, Chicago, Illinois 60611. Manuscript received June 20, 2001; revised manuscript received and accepted October 4, 2001. 359 ©2002 by Excerpta Medica, Inc. All rights reserved. 0002-9149/02/$–see front matter The American Journal of Cardiology Vol. 89 February 1, 2002 PII S0002-9149(01)02244-5