Background and purpose We report the incidence and risk factors for contrast-induced nephropathy after the use of iodinated contrast for endovascular treatment of acute ischemic stroke.
Methods A retrospective chart review was performed in 194 consecutive patients who underwent endovascular treatment for acute ischemic stroke between January 2006 and January 2011. No patients were excluded from treatment for elevated creatinine (Cr). Each patient received approximately 150 ml intra-arterial non-ionic low-osmolar contrast agent (Optiray 320) during the endovascular procedure. Contrast-induced nephropathy (CIN) was defined according to the Acute Kidney Injury Network criteria as a relative increase of serum Cr 50% above the baseline or an absolute increase of 0.3 mg/dl at 48 h following the endovascular procedure.
Results Of 194 patients (mean age 65±14 years), 52% were women (n=100) and 25% (n=48) were diabetic. Baseline Cr levels for 191 patients ranged between 0.4 and 2.7 mg/dl. Three patients on chronic hemodialysis had baseline Cr levels ranging between 5.3 and 6.1 mg/dl. Cr was ≤1.5 mg/dl in 163 patients (84%) and ≥ 1.5 mg/dl in 31 (16%). Three of the 191 patients (1.5%) developed CIN as noted from Cr measurements between baseline and within 48 h. One patient who developed an elevated Cr level had a known history of chronic renal insufficiency (Cr > 1.5 mg/dl) and two had baseline Cr levels within the normal range. An additional CT angiogram was obtained in 44 patients, none of which developed CIN. Female gender and diabetes were not associated with a higher risk of developing CIN.
Conclusions The risk of developing CIN is low among patients with acute stroke who undergo emergency endovascular treatment. Treatment of acute stroke should be performed irrespective of Cr levels.
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Stroke is the third leading cause of mortality and the leading cause of morbidity in the USA. Approximately 780 000 people are diagnosed with stroke annually, of which 85% are ischemic in nature.1 ,2 Patients who present within 3–4.5 h of the onset of symptoms of ischemic stroke are considered for intravenous tissue plasminogen activator administration as a form of conventional treatment.3 However, several studies have shown poor outcomes in patients who present with ischemic stroke secondary to large vessel occlusion despite intravenous thrombolysis.4–9 Recent advances in ischemic stroke treatment have expanded the window to treat these patients with mechanical and chemical interventions through intra-arterial administration.10–17
There is increasing use of endovascular therapy for the treatment of acute ischemic stroke, but data regarding the safety of using contrast media during these procedures are limited. Previous studies have shown an increased incidence of contrast-induced nephropathy (CIN) in patients with myocardial infarction who were treated by an endovascular approach.18–26 Some studies have shown the safety of administration of contrast agents for non-invasive imaging in patients with acute stroke.27–31 However, data regarding CIN in patients with acute ischemic stroke treated by an endovascular approach are sparse. To date, only one small cohort reported in the literature has demonstrated a low rate of contrast-mediated kidney injury following neurointerventional procedures.32
The goal of this study is to assess the incidence and risk factors for CIN after the use of iodinated contrast media in a large number of patients with acute ischemic stroke who underwent endovascular treatment.
Design and goals
An institutional review board-approved retrospective chart review was performed of 194 consecutive patients who underwent endovascular treatment for acute ischemic stroke between January 2006 and January 2010. The primary outcome of this study was the presence of CIN in these treated patients. CIN was defined according to the Acute Kidney Injury Network criteria of a relative increase in serum creatinine (Cr) 50% above the baseline or an absolute increase of 0.3 mg/dl 48 h after the endovascular procedure.
Patient selection and treatment
All 194 patients with acute ischemic stroke who were treated by endovascular intervention between January 2006 and January 2011 were included in this study. Pertinent demographic and clinical data were obtained and analyzed (table 1). The decision for endovascular intervention at our tertiary care center was made by the stroke neurologist and the neurointerventionalist based on the severity of the presenting symptoms and the favorability of non-invasive imaging findings. Patients with large vessel occlusion were considered for endovascular intervention if they presented with symptoms consistent with large vessel occlusion and had no absolute contraindications for intra-arterial therapy. All endovascular neurointerventional procedures were performed using approximately 150 ml of Optiray 320, a non-ionic low-osmolar contrast agent. After the procedure, all patients were kept under continuous medical surveillance in an intensive care unit for at least 24 h. Baseline pre-procedure and post-procedure serum Cr levels within 48 h were analyzed.
The results were expressed as the mean and range for quantitative variables. Power statistical analysis was not performed secondary to the relatively small number of patients who developed CIN.
Of the 194 patients (mean age 65±14 years), 100 (52%) were women and 48 (25%) were diabetic (table 1). Baseline Cr levels for 191 patients ranged between 0.4 and 2.7 mg/dl (mean 1.09). Three patients on hemodialysis had baseline Cr levels ranging from 5.3 to 6.1 mg/dl. Four patients died after the procedure owing to the severity of the stroke and did not have follow-up post-procedure measurement of serum Cr levels. Baseline Cr levels were ≤1.5 mg/dl in 163 patients (84%) and ≥1.5 mg/dl in 31 (16%). Three of the 191 patients (1.5%) developed CIN as noted from Cr measurements between baseline and within 48 h. One patient who developed an increased Cr level had a known history of chronic renal insufficiency (Cr>1.5 mg/dl) and two had baseline Cr levels within the normal range (table 2). Pre-procedure CT angiography was also obtained in 44 patients (22%), none of which developed CIN. Female gender and diabetes were not associated with a higher risk of developing CIN.
Endovascular therapy is emerging as a new treatment option in acute stroke patients. Our study showed that the risk of developing CIN is relatively low among patients with acute stroke who undergo emergency endovascular treatment. Baseline Cr levels were <1.5 mg/dl in 84% of patients and >1.5 mg/dl in 16%. All but two patients with baseline Cr levels <1.5 mg/dl showed no significant change in Cr levels 48–72 h after the procedure. Only one patient with baseline Cr >1.5 mg/dl developed CIN. Female gender, history of diabetes and additional preceding CT angiography in 44 patients were not associated with a higher risk of developing CIN.
Previous studies have shown an increased rate of CIN in 12–26% of patients with myocardial infarction who underwent percutaneous coronary intervention.18–26 Studies have also shown a correlation between CIN and multiple risk factors including diabetes mellitus, a previous history of chronic kidney disease and the amount of contrast used during the procedure.20–26 The majority of the studies that showed a higher incidence of CIN in patients who received contrast agent during the intervention included patients with advanced renal disease, cardiogenic shock, volume depletion, poor ejection fraction and decreased cardiac output secondary to myocardial infarction.
Previous studies have shown a low incidence of CIN in acute stroke patients who underwent emergency multimodal CT scanning. Josephson et al evaluated 1075 patients who received CT contrast studies in acute stroke settings. Forty (3.7%) had an increased Cr level of >0.5 mg/dl.27 Krol et al evaluated 481 patients who underwent CT angiography as a diagnostic modality in acute stroke settings. CIN was defined as an increase of >25% in the serum Cr level from the baseline value up to 5 days after CT angiography. A total of 257 patients were excluded from the study because of lack of data on follow-up Cr level; 224 patients met the inclusion criteria of whom only seven (3%) developed CIN. Only two of 93 patients (2%) who underwent CT angiography without previous knowledge of their Cr level developed CIN. A subgroup of 36 patients who underwent additional digital subtraction angiography did not develop CIN according to the criteria.29 Hopyan et al evaluated 175 patients who underwent CT contrast studies in acute stroke settings; five (2.9%) developed CIN and had an increased Cr level of >25% at follow up (<72 h). None of these patients required dialysis or progressed to renal failure. The results of our study are similar to the previous studies that found a relatively low incidence of CIN among acute stroke patients who underwent emergency endovascular treatment. None of the patients without a previous history of chronic kidney disease developed CIN.30 Loh et al32 reported an incidence of acute CIN of 3% in a cohort of 99 patients undergoing endovascular therapy for acute ischemic stroke.
Limitations of the study are the small sample size and its retrospective nature. Also, because it was a retrospective study, follow-up clinical information to determine long-term evolution of chronic kidney disease in these subjects was not evaluated.
In this study, the risk of developing CIN was low among acute stroke patients who underwent an emergency endovascular intervention. Laboratory investigation should not delay and known renal insufficiency should not preclude intra-arterial treatment of stroke. A prospective randomized clinical trial is warranted to evaluate the long-term effects of use of contrast and interval development of chronic kidney disease.
Correction notice This article has been corrected since it was published Online First. The author Sonal Mehta has been added to the author list.
Contributors All authors contributed significantly to this study and are in agreement with its content. Specifically, JS, RSJ and JP gathered information from the database, performed the statistical analysis and wrote the manuscript. AN and DPH edited the final manuscript. DPH is the primary investigator of this study.
Competing interests None.
Ethics approval IRB committee of Case Western Reserve University.
Provenance and peer review Not commissioned; externally peer reviewed.