Kidney Damage Strikes Roughly One in Fourteen After Key Imaging Procedures, Major Analysis Finds

Every year, millions of patients undergo interventional radiology procedures—minimally invasive operations guided by live X-ray imaging in which thin catheters are threaded through blood vessels to treat strokes, tumors, and hemorrhages. These procedures depend on iodinated contrast media, a dye injected into the bloodstream to make vessels and organs visible on fluoroscopy. But that dye carries a hidden risk: contrast-associated acute kidney injury, or CA-AKI, a sudden deterioration of kidney function that emerges within hours to days after contrast exposure. A new systematic review and meta-analysis published in Frontiers in Radiology has now delivered the most comprehensive picture to date of how often this complication strikes outside the cardiac catheterization laboratory, and the numbers suggest it is anything but rare.

The research team, led by investigators affiliated with King Faisal University and the Saudi Ministry of Health, systematically combed five major medical literature databases—PubMed/MEDLINE, Embase, Scopus, CINAHL, and Web of Science—from their inception through April 30, 2026. Following the PRISMA 2020 reporting standard and a prospectively registered protocol, they screened more than 12,000 records and ultimately included 39 studies, of which 38 contributed quantitative data to the meta-analysis. The procedures covered spanned the full breadth of modern interventional radiology: transarterial chemoembolization (TACE) for liver cancer, neuroendovascular thrombectomy for acute ischemic stroke, aneurysm coiling, carotid artery stenting, bronchial artery embolization for hemoptysis, and hepatic artery embolization, among others.

The headline finding: across all included studies, the pooled incidence of CA-AKI following these non-coronary endovascular procedures was 6.91 percent, with a 95 percent confidence interval of 5.69 to 8.24 percent. In plain terms, roughly one in every fourteen patients who undergoes an interventional radiology procedure involving iodinated contrast experiences some measurable degree of acute kidney injury afterward. A sensitivity analysis restricted to patient-level estimates—30 studies representing 16,825 unique patients—produced a nearly identical figure of 7.27 percent, confirming that the summary estimate was not distorted by studies that counted procedures rather than individual people. Leave-one-out analyses, in which each study was sequentially removed and the pooled estimate recalculated, ranged only from 6.56 to 7.16 percent, demonstrating remarkable numerical stability even though the largest single cohort, a 6,638-patient stroke thrombectomy study, might have been expected to dominate the result.

Yet the stability of the overall number conceals enormous variation underneath it. Individual study-level incidence estimates ranged from 0 percent in selected low-risk embolization cohorts—such as emergency transcatheter arterial embolization for postpartum hemorrhage—to a striking 23.8 percent among patients with hepatocellular carcinoma undergoing repeated TACE sessions. The statistical heterogeneity statistic, I², reached 89.5 percent, far above the 50 percent threshold conventionally used to flag substantial between-study inconsistency. This means the pooled 6.91 percent should be read as a descriptive benchmark across clinically diverse populations rather than a universal expected rate for any given patient or procedure type.

One of the most provocative subgroup findings emerged when the researchers stratified studies by procedure category. Embolization and interventional oncology procedures—dominated by TACE for liver tumors—showed a pooled CA-AKI incidence of 8.44 percent, significantly higher than the 5.48 percent observed after neuroendovascular and carotid procedures (p = 0.0171). The biological logic is compelling: patients undergoing TACE frequently carry cirrhosis, ascites, hypoalbuminemia, and pre-existing renal impairment, all of which compromise the kidney’s ability to withstand the hemodynamic and toxic stresses of contrast exposure. Advanced liver disease disrupts renal perfusion through systemic vasodilation and portal hypertension, creating a physiological milieu in which even modest additional insults can tip the kidneys into injury. Still, the authors caution that heterogeneity remained high within both subgroups, rendering this comparison hypothesis-generating rather than definitive proof that procedure type itself drives the difference.

Beyond procedure category, the analysis identified a consistent constellation of patient-related risk factors reported across the literature. Baseline renal dysfunction was the most repeatedly cited predictor, alongside diabetes mellitus, advanced liver disease, anemia or low hemoglobin, hypoalbuminemia, and greater cumulative contrast exposure. Intriguingly, several neuroendovascular studies also implicated inflammatory biomarkers—elevated neutrophil-to-lymphocyte ratio, systemic inflammatory response indices, and high-sensitivity C-reactive protein—as predictors of CA-AKI following stroke thrombectomy. This suggests that the severe systemic inflammation, ischemia-reperfusion injury, and hemodynamic instability inherent to acute stroke may contribute to renal injury independently of the contrast agent itself, blurring the line between contrast-attributable damage and multifactorial AKI in critically ill patients.

The proposed mechanisms of contrast-associated kidney injury are multifactorial and remain incompletely understood. Iodinated contrast triggers renal vasoconstriction, reducing blood flow to the renal medulla—the oxygen-hungry inner zone of the kidney—creating a state of medullary hypoxia. Contrast agents also generate oxidative stress, injure endothelial cells lining the renal microvasculature, exert direct tubular toxicity, and activate inflammatory pathways. The transition from the older term contrast-induced nephropathy (CIN) to the broader CA-AKI framework reflects growing recognition that renal dysfunction after contrast exposure is often multifactorial, particularly in patients with sepsis, liver failure, or critical illness, where alternative causes of AKI may coexist with contrast exposure.

Perhaps the most clinically consequential finding concerns outcomes. Across individual studies, CA-AKI was associated with increased short-term and long-term mortality, poorer functional recovery, prolonged hospitalization, and persistent renal dysfunction—although these associations were not uniform across all studies and outcomes. In stroke populations, patients who developed CA-AKI after endovascular thrombectomy showed worse modified Rankin Scale scores, increased hemorrhagic transformation, and higher three-month mortality in several cohorts. Among hepatocellular carcinoma patients undergoing TACE, post-procedural AKI was linked to reduced long-term survival and persistent renal impairment. Although most CA-AKI episodes were mild and transient, a minority of patients required renal replacement therapy or developed lasting kidney damage. The message is clear: CA-AKI should not be dismissed as a transient biochemical blip, particularly in medically complex patients undergoing repeated endovascular interventions.

The diagnostic landscape itself complicates the picture. Included studies used wildly varying definitions of CA-AKI—KDIGO, AKIN, International Club of Ascites, ESUR criteria, and study-specific CIN thresholds—spanning ascertainment windows from roughly 24 hours to 7 days after contrast exposure. Subgroup analysis found that studies using standardized definitions reported a pooled incidence of 5.67 percent, versus 7.76 percent for studies using study-specific or CIN-based criteria, a numerical difference that did not reach statistical significance but hints that looser definitions may inflate apparent incidence. More troubling, emerging evidence suggests serum creatinine—the workhorse biomarker of AKI—may underestimate renal injury in interventional settings. One neuroendovascular study detected subclinical kidney damage using urine neutrophil gelatinase-associated lipocalin (uNGAL) even when creatinine-based criteria showed paradoxical post-procedural improvements, attributed to hemodilution and fluid shifts masking early tubular injury.

The authors did not establish a clinically reliable contrast-volume threshold from the heterogeneous observational evidence, and associations between repeated procedures and CA-AKI risk may partly reflect underlying disease severity rather than contrast dose alone. Periprocedural hydration strategies and hemodynamic factors such as procedural hypotension were inconsistently reported across studies, precluding reliable subgroup analysis of these potentially modifiable variables. Using the GRADE framework, the certainty of evidence for the principal incidence estimates was rated as very low, reflecting the observational nature of all included studies, moderate-to-high risk of bias in a substantial proportion, and marked inconsistency across the evidence base. No randomized controlled trials met the eligibility criteria, and all evidence was derived exclusively from adult populations—no pediatric studies qualified for inclusion.

The clinical implications are nonetheless actionable. Patients with advanced liver disease, baseline renal dysfunction, diabetes, anemia, hypoalbuminemia, or high inflammatory burden may benefit from enhanced renal-protective strategies before and after interventional radiology procedures. Procedural planning should minimize unnecessary contrast exposure whenever clinically feasible, though the absence of a validated contrast-volume threshold means clinical judgment must guide dose reduction. The researchers emphasize that broader adoption of contemporary KDIGO-based definitions could improve comparability across future studies, and they call for prospective multicentre research to establish procedure-specific risk profiles, evaluate preventive strategies, and clarify the long-term renal and clinical consequences of CA-AKI in interventional radiology populations. For now, the analysis provides a quantitative benchmark—roughly seven percent across non-coronary interventional procedures—that clinicians can use to contextualize risk when consenting patients, while recognizing that the true figure for any individual procedure and population may sit meaningfully above or below that average.

Subject of Research: Incidence, risk factors, and outcomes of contrast-associated acute kidney injury following interventional radiology procedures: a systematic review and meta-analysis

Article Title: Incidence, risk factors, and outcomes of contrast-associated acute kidney injury following interventional radiology procedures: a systematic review and meta-analysis

Article References: Alhumaid, S., Almulhim, M. Y., Al Hussaini, H. A., Alalwan, Q. M., Almohammed Ali, H., Al Ruzaihan, S. A., Aborshaid, F. A., Al Abdulqader, A. K., Al Dossary, N., Alabdulqader, M., AlMousa, S. S., & Aljoqiman, K. S. (2026). Incidence, risk factors, and outcomes of contrast-associated acute kidney injury following interventional radiology procedures: a systematic review and meta-analysis. Frontiers in Radiology, 6, Article 1947256. https://doi.org/10.3389/fradi.2026.1947256

Image Credits: AI Generated

DOI: 10.3389/fradi.2026.1947256

Keywords: Incidence, risk, factors, outcomes, contrast-associated, acute, kidney, injury, following, interventional, radiology, procedures