The impact of chronic kidney disease as a predictor of major cardiac events in patients with no evidence of coronary artery disease.

BACKGROUND: Normal stress myocardial perfusion images (MPI) generally show good prognosis for cardiovascular events. However, chronic kidney disease (CKD) is one of the important risk factors for coronary artery disease (CAD), and the interpretation of normal stress MPI has not been well established in CKD patients with no evidence of CAD. The purpose of this study was to evaluate the long-term prognostic value of stress MPI in CKD patients with no evidence of myocardial ischemia or infarction.

METHODS: Patients who had no history but were suspected of CAD and had normal stress MPI (n=307, male=208, age=67 years, CKD/non-CKD=46/261) were followed-up for 4.5 years. CKD was defined as a glomerular filtration ratio of <60 ml/min/1.73 m(2) and/or persistent proteinuria. Cardiac death, non-fatal myocardial infarction, and unstable angina requiring hospitalization were defined as major cardiac events.

RESULTS: Major cardiac events were observed in 3 of 261 (1.1%) non-CKD patients and 6 of 46 (13%) CKD patients (p<0.001, with log-rank test). CKD was an independent risk factor for major cardiac events (hazard ratio=13.1, p<0.001, multivariate Cox regression analysis).

CONCLUSIONS: Normal stress MPI does not always promise a good prognosis for major cardiac events. Even in patients with no evidence of CAD from stress MPI, CKD can be an independent and significant risk factor for major cardiac events.