Long-term survival after cardiac surgery is predicted by estimated glomerular filtration rate.

BACKGROUND: Estimated glomerular filtration rate (eGFR) before coronary artery bypass graft (CABG) surgery is a key risk factor of in-hospital mortality. However, in patients with normal renal function before CABG, acute kidney injury develops after the procedure, making postoperative renal function assessment necessary for evaluation. Postoperative eGFR and its association with long-term survival have not been well studied. METHODS: We studied 13,593 consecutive CABG patients in northern New England from 2001 to 2006. Patients with preoperative dialysis were excluded. Data were linked to the Social Security Association Death Master File to assess long-term survival. Kaplan-Meier and log-rank techniques were used. Patients were stratified by established categories of postoperative eGFR (90 or greater, 60 to 89, 30 to 59, 15 to 29, and less than 15 mL x min(-1) x 1.73 m(-2)). RESULTS: Median follow-up was 2.8 years (mean, 2.7; range, 0 to 5.5). Patients with moderate to severe acute kidney injury (less than 60) after CABG had significantly worse survival than patients with little or no acute kidney injury (90 or greater). CONCLUSIONS: Patients having moderate to severe acute kidney injury after CABG surgery had worse 5-year survival compared with patients who had normal or near-normal renal function.

Long-term survival after surgery versus percutaneous intervention in octogenarians with multivessel coronary disease.

BACKGROUND: There is limited information comparing long-term survival after percutaneous coronary intervention (PCI) versus coronary artery bypass grafting (CABG) in patients aged 80 years and older. We studied the long-term survival of octogenarians with multivessel coronary artery disease undergoing PCI or CABG who might have been candidates for either procedure. METHODS: We identified 1693 patients, aged 80 to 89, with two-vessel disease (57.6%) or three-vessel disease (42.4%), without left main disease, undergoing a first, nonemergency revascularization from 1992 to 2001. Adjusted hazard ratios (HR) were calculated for CABG versus PCI. Because survival curves for these procedures crossed midway through year 1, results were analyzed separately for the first 6 months and 6 months to 8 years. RESULTS: PCI was performed in 54.6% of patients with two-vessel disease and 23.7% of those with three-vessel disease. More CABG patients were men (54.7% versus 43.3%). The CABG patients had more peripheral vascular disease (23.1% versus 15.2%) and congestive heart failure (24.5% versus 13.1%) but less renal failure (4.6% versus 9.1%) and fewer prior myocardial infarctions (48.7% versus 53.6%). In-hospital mortality was 3.0% for PCI and 5.9% for CABG (p = 0.005). CABG was associated with poorer survival than PCI during the first 6 months (HR, 1.32; p = 0.135). Survival from 6 months to 8 years was significantly better with CABG for the group as a whole (HR, 0.72; p = 0.005) and for patients with two-vessel disease (HR, 0.68; p = 0.016), and there was a nonsignificant trend for those with three-vessel disease (HR, 0.75; p = 0.177). CONCLUSIONS: Patients aged 80 years or older with multivessel disease must consider the trade-off between the increased early risks of CABG in return for improved long-term survival.

Multivariable prediction of renal insufficiency developing after cardiac surgery.

BACKGROUND: Renal insufficiency after coronary artery bypass graft (CABG) surgery is associated with increased short-term and long-term mortality. We hypothesized that preoperative patient characteristics could be used to predict the patient-specific risk of developing postoperative renal insufficiency. METHODS AND RESULTS: Data were prospectively collected on 11,301 patients in northern New England who underwent isolated CABG surgery between 2001 and 2005. Based on National Kidney Foundation definitions, moderate renal insufficiency was defined as a GFR <60 mL/min/1.73 m2 and severe renal insufficiency as a GFR <30. Patients with at least moderate renal insufficiency at baseline were eliminated from the analysis, leaving 8363 patients who became our study cohort. A prediction model was developed to identify variables that best predicted the risk of developing severe renal insufficiency using multiple logistic regression, and the predictive ability of the model quantified using a bootstrap validated C-Index (Area Under ROC) and Hosmer-Lemeshow statistic. Three percent of the patients with normal renal function before CABG surgery developed severe renal insufficiency (229/8363). In a multivariable model the preoperative patient characteristics most strongly associated with postoperative severe renal insufficiency included: age, gender, white blood cell count >12,000, prior CABG, congestive heart failure, peripheral vascular disease, diabetes, hypertension, and preoperative intraaortic balloon pump. The predictive model was significant with chi2 150.8, probability value <0.0001. The model discriminated well, ROC 0.72 (95%CI: 0.68 to 0.75). The model was well calibrated according to the Hosmer-Lemeshow test. CONCLUSIONS: We developed a robust prediction rule to assist clinicians in identifying patients with normal, or near normal, preoperative renal function who are at high risk of developing severe renal insufficiency. Physicians may be able to take steps to limit this adverse outcome and its associated increase in morbidity and mortality.

Perioperative increases in serum creatinine are predictive of increased 90-day mortality after coronary artery bypass graft surgery.

BACKGROUND: Impaired renal function after coronary artery bypass graft (CABG) surgery is a key risk factor for in-hospital mortality. However, perioperative increases in serum creatinine and the association with mortality has not been well-studied. We assessed the hypothesis that perioperative increases in creatinine are associated with increased 90-day mortality. METHODS AND RESULTS: We studied 1391 patients in northern New England undergoing CABG in 2001 and evaluated preoperative and postoperative creatinine. Patients with preoperative dialysis were excluded. Data were linked to the National Death Index to assess 90-day survival. Kaplan-Meier and log-rank techniques were used. Patients were stratified by percent increase in creatinine from baseline: <25%, 25% to 49%, 50% to 99%, > or =100%. We assessed 90-day survival and calculated adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) for creatinine groups, adjusting for age and sex. Patients with the largest creatinine increases (50% to 99% or > or =100%) had significantly higher 90-day mortality compared with patients with a smaller increase (<50%; P<0.001). Adjusted HR and 95% CI confirmed patients in the higher 2 groups had an increased risk of mortality compared with the <25% (referent); however, the 25% to 49% group was not different from the referent: 1.80 (95% CI: 0.73 to 4.44), 6.57 (95% CI, 3.03 to 14.27), and 22.10 (95% CI, 11.25 to 43.39). CONCLUSIONS: Patients with large creatinine increases (> or = 50%) after CABG surgery have a higher 90-day mortality compared with patients with small increases. Efforts to identify patients with impaired renal function and to preserve renal function before cardiac surgery may yield benefits for patients in the future.