Neutrophil gelatinase-associated lipocalin, cystatin C and eGFR indicate acute kidney injury and predict prognosis of patients with acute pulmonary embolism.

OBJECTIVE: Risk stratification in acute pulmonary embolism (APE) includes the assessment of clinical status, right ventricular dysfunction and troponin concentrations. Since acute renal impairment is one of the important predictors of mortality in cardiovascular diseases, the authors hypothesised that it is an independent mortality marker in APE.

MATERIAL AND METHODS: The authors observed 142 consecutive patients (52 M/90 F, 64±18 years) with APE diagnosed with contrast enhanced multislice CT. On admission, blood samples were collected for neutrophil gelatinase-associated lipocalin (N-GAL), cystatin C and creatinine assays. Estimated glomerular filtration rate (eGFR) was calculated using MDRD formula.

RESULTS: Fourteen (10%) of 142 patients died by the 30th day of observation. eGFR≤60 ml/min was noted in 68 (48%) patients and eGFR≤30 ml/min in 11 (8%) patients. eGFR was higher in survivors than in non-survivors (66 (17-169) vs 46 (10-119) ml/min, respectively, p=0.02). In 80 (56%) patients, N-GAL was >50 ng/ml indicating acute kidney injury. N-GAL was higher in non-survivors than in survivors (88.8 (28.4-200.0) vs 53.0 (7.1-200.0) ng/ml, p<0.01). N-GAL level >50 ng/ml was found in 11 (79%) patients with fatal outcome. Area under the curve of N-GAL for all-cause mortality in ROC analysis was 0.715. N-GAL>75 ng/ml was present in 44 (31%) patients, while cystatin C >1900 ng/ml in 14 (10%) subjects. They showed sensitivity, specificity, positive predictive value and negative predictive value for prediction of all-cause death ((64%, 73%, 21%, 95%) and (36%, 91%, 30% 93%), respectively). N-GAL>75 ng/ml and cystatin C>1900 ng/ml increased the risk of death (HR 4.4 (95% CI 1.48 to 13.2, p<0.01) and 4.7 (95% CI 1.56 to 13.9, p=0.01), respectively).

CONCLUSIONS: Acute kidney injury assessed by N-GAL occurs in 30% of APE and may contribute to the impairment of renal function present in half of them. Moreover, N-GAL, cystatin C elevation and low eGFR are associated with a poor 30-day prognosis in APE.