Introduction

1. The prevalence of coronary artery disease (CAD) in renal transplantation candidates is approximately 40-50% [1-5]. Thus, the reason why cardiac evaluation for the detection of CAD is an essential component of pre-renal transplantation assessment. The Canadian Society of Transplantation as of 2005 recommends the following as guidelines for cardiac evaluation [6]: • All patients should be assessed for ischemic heart disease (IHD) before kidney transplantation through a detailed history and physical examination, ECG and chest radiography. • Further testing for IHD depends on the probability CAD. All symptomatic patients or high risk asymptomatic patients with diabetes mellitus (type 1 or 2) or three or more risk factors (age > 50 years, prolonged duration of chronic kidney disease (CKD), family history of CAD, smoking history, dyslipidemia (HDL < 0.9 mmol/L or total cholesterol > 5.2 mmol/L), BMI ≥ 30 kg/m2, and/or hypertension should be further assessed with non-invasive testing. • All patients with a positive non-invasive test should be referred for coronary angiography (CA). Patients who had a negative non-invasive test but are determined to be at very high risk clinically be considered for CA as well. • Re-evaluation of IHD should occur on a regular basis or when a patient a patient becomes symptomatic. The predominant non-invasive test used in Saskatchewan is a myocardial perfusion scan (MPS). The test is conducted at rest and after a cardiac stressor is applied (exercise or pharmaceutical such as dipyridamole) [4] and uses an injected radioactive tracer to measure the myocardial blood flow. As there are no clear guidelines about how frequent routine re-evaluation show occur, all pre-renal transplantation patients in Saskatchewan are recommended to undergo annual cardiac evaluation with MPS. The results of the myocardial perfusion scans identified 54 (48%) abnormal reports out of the 113 patients (Figure 1). • 38 (34%) patients were identified as having a reversible defect, 8 of which had a LVEF of less than 40%. • 10 (9%) patients were reported having a fixed defect, with 6 having a LVEF less than 40%. • 6 (5%) had an LVEF of less than 40% but did not have a perfusion defect identified. Figure 1. Breakdown of MPS Results: Normal and Abnormal (Fixed, Reversible, LVEF <40) Introduction RATE OF CHANGE IN SERIAL MYOCARDIAL PERFUSION RESULTS IN PATIENTS WAITING FOR RENAL TRANSPLANTATION Lucas Zahorski, Bhanu Prasad, Glen Olenberger, Dakshina Murthy, V Trivedi, Payam Dehghani Objective Methods The Saskatchewan Transplant Program: Renal Transplant Registry was used to identify pre-renal transplantation patients from 2005 to 2012. This list was then further refined to only pre-renal transplantation patients who have underwent cardiac evaluation with MPS between the time period of 2004 to 2012 in Regina. MPS reports were than obtained and analyzed to identify normal and abnormal results. Abnormal MPS reports were defined as any of the following: • Fixed perfusion defect: indicating myocardial scarring • Transient/reversible perfusion defect: indicating myocardial ischemia • LVEF < 40% in the absence of any perfusion defect Once the reports were identified, the rate of change from normal to abnormal myocardial perfusion results was calculated using the following formula: # of Previously Normal Scan Becomes Abnormal in Subsequent Scan Total # of Subsequent Scans That Were Previously Normal Statistical analyses for this study were performed using SPSS data analysis software and Microsoft Excel. This study was granted ethical approval from the Regina Qu’Appelle Health Region Research Ethics Board. Results In a heterogeneous population of patients awaiting renal transplantation in Saskatchewan, about 1 in 3 patients had change in their subsequent perfusion scan. Several limitations to this study were identified over the course of the research period. • Firstly, the population size was smaller than originally anticipated. • Secondly, there is a lack of comparable literature available currently. This has made it difficult to determine the true significance of the nearly 1 in 3 rate of change we identified. • Lastly, the definition of an abnormal scan result used for this study was very arbitrary. This study classified abnormal perfusion defects as purely fixed or reversible. Future studies will need to further classify defects as being mild, moderate or severe. Updated data for the entire province of Saskatchewan will be available in October 2012. References De Lima JJG, Henrique L, Gowdak W et al. Validation of a strategy to diagnose coronary artery disease and predict cardiac events in high-risk transplant candidates. Coronary Artery Disease 2010; 21: 164-167. Enkiri SA, Taylor AM, Keeley EC et al. Coronary angiography is the better predictor of mortality than noninvasive testing in patients evaluated for renal transplantation. Catheterization and Cardiovascular Interventions 2010; 76: 795-801. De Lima JJG, Sabbaga E, Vieira MLC et al. Coronary angiography is the best predictor of events in renal transplant candidates compared with noninvasive testing. Hypertension 2003; 42: 263-268. De Vriese AS, Vandecasteele SJ, Van den Bergh et al. Should we screen for coronary artery disease in asymptomatic chronic dialysis patients? Kidney International 2012; 81: 143-151 Delos Santos RB, Gmurczyk A, Obhrai JS et al. Cardiac evaluation prior to kidney transplantation. Semin Dial 2010; 23(3): 324–329. Knoll G, Cockfield S, Blydt-Hansen T et al. Canadian Society of Transplantation consensus guidelines on the eligibility for kidney transplantation. CMAJ 2005; 173(10): S1-S25. Berman DS, Germano G. Nuclear Cardiology: Where do we stand?. Available from: http://www.fac.org.ar/cvirtual/cvirteng/cienteng/ mneng/mnm3007i/iberman/berman2.htm Results Continued The objective of this study was to calculate the rate of change in serial myocardial perfusion scans in a heterogeneous population of patients awaiting renal transplantation. Conclusion • 113 of the 189 patients on the Renal Transplant Register from 2005 to 2012 underwent cardiac evaluation with MPS in Regina. Of these 113, 45 (40%) patients had a single scan and 68 (60%) had multiple scans completed between 2004 to 2012 (Table 1). • Patients underwent an average of 2.08±1.20 scans (median= 2) with an average duration of 1.84±0.97 years between the next repeat scan (Table 1). • Table 1. Number of scans had by patients and average duration between scans • The average rate of change in subsequent scans was determined to be 30.7±3.3%. • A complete breakdown is seen in Table 2. • Table 2. Results of Sequential MPS and Rate of Change from Normal to Abnormal Scans The 20 Segment model is the scoring system used to identify the location and severity of perfusion defects on a MPS [7} • The mean age of the patients at the time of their initial scan was 53.46±11.94 years (min= 20, max= 75). Photo from: http://www.nhsggc.org.uk/content/default.asp?page=s1440_1