Cardiac scintigraphy fails to identify patients with single-vessel coronary artery disease and end-stage renal disease: potential impact on cardiovascular morbidity

Abstract

Introduction: Patients (pt) with end-stage renal disease (ESRD) are at increased risk for CAD and major adverse cardiovascular events. Cardiac scintigraphy is regarded as a non-invasive, useful screening tool for risk stratification and to exclude significant CAD in the general population; invasive coronary angiography is usually performed following a positive result in the non-invasive assessment. Objectives: To determine the accuracy of such approach in pt with ESRD being considered as renal transplant candidates. Methods: 482 pt with ESRD (56 ±9 years; 69% men) underwent cardiac scintigraphy (99mTc MIBI-SPECT with dipyridamole) and coronary angiography, regardless of symptoms. Myocardial perfusion scans were categorized as normal or abnormal (fixed and/or transient perfusion defects); significant CAD was defined by luminal stenosis ≥70%. The sensitivity (Sen), specificity (Spe), positive (PPV) and negative (NPV) predictive values were calculated for pt with 1-, 2- or 3-vessel CAD. Kaplan-Meier curves were constructed for the probability of survival free of fatal/non-fatal MACE during a 5-year follow-up based on the results of angiography. Results: 240 pt (50%) had perfusion defects; 237 pt (49%) had significant CAD, of which 89 (38%), 70 (29%), and 78 (33%) had 1-, 2-, and 3-vessel disease, respectively. Figure 1 shows that pt with any degree of significant CAD had a worse-long term prognosis than pt with no CAD. Figure 2 shows that abnormal myocardial scans were more likely to be found in pt with 2- (69%) or 3-vessel CAD (76%), whereas in pt with no CAD, 64% of them had a normal perfusion scan (P<0.0001). However, in pt with 1-vessel CAD, the occurrence of normal and abnormal scans was almost identical (48 vs. 52%). A myocardial perfusion defect yielded a Sen=52%, 69% and 76%, a Spe=28%, 37% and 41%, a PPV=30%, 31% and 39%, and a NPV = 49%, 74% and 77% for the diagnosis of 1-, 2- and 3-vessel CAD, respectively. Conclusion: In pt with ESRD: 1) the prevalence of significant CAD is high, and this imposes a worse long-term prognosis independently of the number of affected vessels; 2) myocardial perfusion assessment by SPECT has a low sensitivity to detect 1-vessel CAD; 3) as a consequence, many pt with 1-vessel CAD could be mistakenly deemed to be free of CAD and, therefore, not treated accordingly, although their long-term prognosis seemed to be no different of that from pt with 2- or 3-vessel disease.