Comparison of Two Risk Models in Predicting the Incidence of Contrast-Induced Nephropathy after Percutaneous Coronary Intervention

Clinical and economic outcomes of assigning percutaneous coronary intervention patients to contrast-sparing strategies based on the predicted risk of contrast-induced acute kidney injury

OBJECTIVE

Contrast-sparing strategies have been developed for percutaneous coronary intervention (PCI) patients at increased risk of contrast-induced acute kidney injury (CI-AKI), and numerous CI-AKI risk prediction models have been created. However, the potential clinical and economic consequences of using predicted CI-AKI risk thresholds for assigning patients to contrast-sparing regimens have not been evaluated. We estimated the clinical and economic consequences of alternative CI-AKI risk thresholds for assigning Medicare PCI patients to contrast-sparing strategies.

METHODS

Medicare data were used to identify inpatient PCI from January 2017 to June 2021. A prediction model was developed to assign each patient a predicted probability of CI-AKI. Multivariable modeling was used to assign each patient two marginal predicted values for each of several clinical and economic outcomes based on (1) their underlying clinical and procedural characteristics plus their true CI-AKI status in the data and (2) their characteristics plus their counterfactual CI-AKI status. Specifically, CI-AKI patients above the predicted risk threshold for contrast-sparing were reassigned their no CI-AKI (counterfactual) outcomes. Expected event rates, resource use, and costs were estimated before and after those CI-AKI patients were reassigned their counterfactual outcomes. This entailed bootstrapped sampling of the full cohort.

RESULTS

Of the 542,813 patients in the study cohort, 5,802 (1.1%) had CI-AKI. The area under the receiver operating characteristic curve for the prediction model was 0.81. At a predicted risk threshold for CI-AKI of >2%, approximately 18.0% of PCI patients were assigned to contrast-sparing strategies, resulting in (/100,000 PCI patients) 121 fewer deaths, 58 fewer myocardial infarction readmissions, 4,303 fewer PCI hospital days, $11.3 million PCI cost savings, and $25.8 million total one-year cost savings, versus no contrast-sparing strategies.

LIMITATIONS

Claims data may not fully capture disease burden and are subject to inherent limitations such as coding inaccuracies. Further, the dataset used reflects only individuals with fee-for-service Medicare, and the results may not be generalizable to Medicare Advantage or other patient populations.

CONCLUSIONS

Assignment to contrast-sparing regimens at a predicted risk threshold close to the underlying incidence of CI-AKI is projected to result in significant clinical and economic benefits.

National Cardiovascular Data Registry-Acute Kidney Injury (NCDR) vs. Mehran risk models for prediction of contrast-induced nephropathy and need for dialysis after coronary angiography in a German patient cohort

BACKGROUND

Contrast-induced nephropathy (CIN) is a major adverse event in patients undergoing coronary angiography. The Mehran risk model is the gold-standard for CIN risk prediction. However, its performance in comparison to more contemporary National Cardiovascular Data Registry-Acute Kidney Injury (NCDR-AKI) risk models remains unknown. We aimed to compare both in this study.

METHODS AND RESULTS

Predictions of Mehran and NCDR-AKI risk models and clinical events of CIN and need for dialysis were assessed in a total of 2067 patients undergoing coronary angiography with or without percutaneous coronary intervention. Risk models were compared regarding discrimination (receiver operating characteristic analysis), net reclassification improvement (NRI) and calibration (graphical and statistical analysis). The NCDR risk model showed superior risk discrimination for predicting CIN (NCDR c-index 0.75, 95% CI 0.72-0.78; vs. Mehran c-index 0.69, 95% CI 0.66-0.72, p < 0.01), and continuous NRI (0.22; 95% CI 0.12-0.32; p < 0.01) compared to the Mehran model. The NCDR risk model tended to underestimate the risk of CIN, while the Mehran model was more evenly calibrated. For the prediction of need for dialysis, NCDR-AKI-D also discriminated risk better (c-index 0.85, 95% CI 0.79-0.91; vs. Mehran c-index 0.75, 95% CI 0.66-0.84; p_NCDRvsMehran < 0.01), but continuous NRI showed no benefit and calibration analysis revealed an underestimation of dialysis risk.

CONCLUSION

In German patients undergoing coronary angiography, the modern NCDR risk model for predicting contrast-induced nephropathy showed superior discrimination compared to the GRACE model while showing less accurate calibration. Results for the outcome 'need for dialysis' were equivocal.

Advances in the pathogenesis and prevention of contrast-induced nephropathy

With the increasing application of medical imaging contrast materials, contrast-induced nephropathy has become one of the leading causes of iatrogenic renal insufficiency. The underlying mechanism is associated with renal medullary hypoxia, direct toxicity of contrast agents, oxidative stress, apoptosis, immune/inflammation and epigenetic regulation in contrast-induced nephropathy. Up to date, there is no effective therapy for contrast-induced nephropathy, and thus risk predication and effective preventive strategies are keys to reduce the occurrence of contrast-induced nephropathy. It was found that the proper use of contrast medium, personalized hydration, and high-dose statins may reduce the occurrence of contrast-induced nephropathy, while antioxidants have not shown significant therapeutic benefits. Additionally, the role of remote ischemia preconditioning and vasodilators in the prevention of contrast-induced nephropathy needs further study. This review aims to discuss the incidence, pathogenesis, risk prediction, and preventive strategies for contrast-induced nephropathy.

Nephrotoxicity of gadolinium-based contrast in the setting of renal artery intervention: retrospective analysis with 10-year follow-up

PURPOSE

We aimed to determine the incidence rate and potential risk factors for postcontrast acute kidney injury (PC-AKI) as well as the long-term clinical implications on dialysis and mortality in patients with chronic kidney disease (CKD) who underwent renal artery stent placement exclusively with gadolinium-based contrast agents.

METHODS

This retrospective study reviewed 412 patients with CKD who underwent renal artery stent placement. Sixty-eight patients underwent intervention exclusively with gadolinium-based contrast agents and were analyzed. Criteria for PC-AKI included either an absolute serum creatinine increase >0.3 mg/dL or percentage increase in serum creatinine >50% within 48 hours of intervention. Logistic regression analysis was performed to identify risk factors for PC-AKI. The cumulative proportion of patients who died or went on to hemodialysis was determined using Kaplan-Meier survival analysis.

RESULTS

The incidence of PC-AKI was 14.7%. The rate of AKI decreased for every 1 unit increase in glomerular filtration rate ( GFR, odds ratio [OR]=0.91, P = 0.047). Prehydration was associated with a lower PC-AKI rate (OR=0.17; P = 0.015). Acute kidney injury after intervention was associated with an increased rate of dialysis (Hazard ratio [HR]=4.51, P = 0.002) and mortality (HR=2.52; P = 0.027).

CONCLUSION

Gadolinium-based contrast agents are potentially nephrotoxic when used for endovascular intervention in patients with CKD. The risk of PC-AKI increased with lower GFR and decreased with prehydration. Dialysis and mortality risk were increased in patients who developed PC-AKI.

Comparison of the Effect of Dual-Axis Rotational Coronary Angiography Versus Conventional Coronary Angiography on Frequency of Acute Kidney Injury, X-Ray Exposure Time, and Quantity of Contrast Medium Injected

Dual-axis rotational coronary angiography (DARCA) has already been shown to reduce both the amount of contrast medium and radiation exposure compared with conventional coronary angiography (CCA). However, a clinical benefit of such imaging modality has never been demonstrated. The aim of this study was to evaluate the efficacy of DARCA to prevent acute kidney injury (AKI) compared with CCA. Consecutive patients who underwent coronary angiography were enrolled to DARCA (n = 80) or CCA (n = 80). Patients presenting with ST-segment elevation myocardial infarction or previously underwent coronary artery bypass graft were excluded. The 2 groups were homogeneous in terms of both clinical and procedural characteristics. Total x-ray time and total amount of contrast medium were significantly lower in the DARCA group compared with the CCA group (x-ray time 3.2 minutes [1.8 to 7.0] vs 5.1 minutes [2.6 to 9.9], p = 0.002; contrast medium amount 40 ml [31 to 116] vs 80 ml [50 to 150], p <0.001). AKI more often occurred in the CCA group compared with the DARCA group (16 [20%] vs 4 [5%], p = 0.007). Moreover, in patients presenting with acute coronary syndrome (ACS) or who underwent percutaneous coronary intervention (PCI), AKI more often occurred in the CCA group compared with the DARCA group (ACS patients, 6 [29%] vs 2 [6%], p = 0.04, and PCI patients, 11 [33%] vs 0 [0%], p <0.001). In addition, in patients with high pretest probability of coronary artery disease, AKI more often occurred in the CCA group compared with the DARCA group (11 [55%] vs 2 [6%], p <0.001). In conclusion, DARCA significantly reduces both x-ray exposure and amount of contrast medium usage, thereby reducing the occurrence of AKI compared with CCA.