Incremental prognostic value of coronary artery disease and renal function on the prediction of cardiovascular events of patients evaluated by coronary computed tomography: the partners registry

Abstract

Background: Limited data exists on whether chronic kidney disease adds prognostic value after accounting for the presence and severity of coronary plaque. Therefore, we evaluated the incremental prognostic value of renal function and the presence and severity of coronary artery disease (CAD) detected by coronary computed tomography angiography (CCTA) in the development cardiovascular events. Methods: CCTA scans performed at two tertiary hospitals within Partners Healthcare system (Boston, Massachusetts) between 09/2004 and 10/2011 were retrospectively analyzed. We included all consecutive patients who underwent CCTA without known prior CAD and had at least one value of creatinine available prior to the scan. The renal function (eGFR) was estimated by the MDRD formula. CCTA results were categorized as normal, non-obstructive (<50%) or obstructive (≥50%). Blinded event adjudication was performed. All self-reported events were verified. Results: 1541 (43% female) patients were included. The mean age was 55.4 ± 13.7. Overall, 653 (42%) of the patients had no CAD, 583 (38%)-had non- obstructive and 305 (20%) had obstructive CAD, while 361 (23%) had eGFR >90 mL/min/1.73 m2, 938 (61%) had eGFR 60-90 mL/min/1.73 m2, and 242 (16%) eGFR <60 mL/min/1.73 m2. The presence and severity of CAD as well as lower eGFR were associated with increased rate of cardiovascular death or myocardial infarction. In a model adjusted for age, gender, symptoms, and risk factors, eGFR <60 was associated with increased risk of events, while the eGFR 60 to 90 was nor. The inclusion of eGFR in the model results iimproved model fit for the prediction of CV death ar MI (p=0.01) and all cause death (p<0.0001). Conclusion: In individuais referred for CCTA to evaluate CAD, renal function improves the prediction of future cardiovascular events in patients with eGFR <90. This finding defines a subgroup of patients with higher cardiovascular risk and greater benefit of aggressive medical management.