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Published on: August 28, 2018
Predictors of worsening renal function after computed tomography coronary angiography: assessed by cystatin C
Hirohiko Ando1, Satoshi Isobe, Tetsuya Amano
1Department of Cardiology, Kami-iida Dai-ichi General Hospital, 2-70 Kami-iida, Kita-machi, Kita-ku, Nagoya, 462-0802, Japan.
Insights
Adequate hydration is key to preventing kidney function decline after contrast-enhanced coronary computed tomography angiography (CTA). Insufficient fluid intake, especially in diabetic patients, increases the risk of elevated cystatin C (CyC) levels, a marker of kidney injury.
Area of Science:
- Nephrology
- Radiology
- Cardiology
Background:
- Elevated cystatin C (CyC) after 24 hours may predict contrast-induced nephropathy and adverse outcomes in patients with renal dysfunction undergoing invasive coronary angiography.
- Contrast-enhanced coronary computed tomography angiography (CTA) involves iodinated contrast media, posing a risk to renal function.
Purpose of the Study:
- To investigate changes in CyC in patients with preserved renal function undergoing contrast-enhanced coronary CTA.
- To identify predictors of CyC elevation in this patient cohort.
Main Methods:
- 151 patients undergoing CTA with 70 mL of iopamidol were studied.
- Serum creatinine and CyC were measured pre-CTA and 1 day and 1 week post-CTA.
- Percentage change in CyC (%CyC) was correlated with fluid intake and glycemic control (HbA1c).
Main Results:
- 47 patients (31%) showed a ≥10% increase in CyC 1 day post-CTA.
- This group had higher rates of diabetes, higher HbA1c, and lower oral fluid intake.
- Oral fluid intake and HbA1c were independent predictors of %CyC elevation.
Conclusions:
- Frequency of CyC elevation was strongly related to hydration status post-CTA.
- Sufficient oral fluid intake (≥20 mL/kg) is crucial for preventing CyC elevation, particularly in diabetic patients.
- Even with preserved renal function, hydration is vital before CTA to mitigate kidney function changes.
Background:
An increase in cystatin C (CyC) of ≥10% for 24 hours may predict contrast-induced nephropathy and worse outcomes in patients with renal dysfunction undergoing invasive coronary angiography.
Objective:
We investigated the changes in CyC in patients with preserved renal function referred for contrast-enhanced coronary computed tomography angiography (CTA).
Methods:
We studied 151 patients undergoing CTA with 70 mL of iopamidol. Serum creatinine and CyC, a sensitive measure of renal dysfunction, shown to be associated with adverse outcomes, were measured 1 day and 1 week after CTA, respectively. The percentage change in CyC (%CyC) was determined and evaluated in comparison to fluid intake.
Results:
The patients were dichotomized into 2 groups: 47 patients had ≥10% increase in CyC 1 day after CTA (group A) and 104 did not (group B). The percentage of diabetic patients, hemoglobin A1c (HbA1c), and the CyC levels at 1 week were significantly greater, and the oral fluid volume was significantly lower in group A than in group B. The %CyC inversely correlated with oral fluid volume (r = -0.80, P < 0.0001) and positively with HbA1c (r = 0.38, P < 0.001). Multiple regression analysis showed that oral fluid intake (β = -0.796, P < 0.0001) and HbA1c (β = 0.128, P = 0.007) are independent predictors for %CyC of ≥10%.
Conclusion:
Frequency of CyC elevation was strongly related to hydration after the study and also weakly related to HbA1c. Sufficient oral fluid intake (oral fluid volume/kg ≥ 20 mL/kg) is crucial, particularly for poorly controlled diabetic patients referred for CTA even though they show preserved renal function.
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