Contrast-induced acute kidney injury
Definition
- increase in the creatinine of 0.5mg/dL or a 25% increase from basline w/i 3 days after the contrast media
- and abscense of alternative cause (CIAKI) (NEJM 2019;380:2146)
natural history
- 24-48h increase after exposure and peak at 3-5 days
- resolves in 7 to 10 days
- if prolonged duration: look for other cause, e.g. atheroeboli after arteriography
- AKI 24–48 h post contrast, peaks 3–5 d, resolves 7–10 d (consider chol emboli if does not)
incidence:
- 0.5% patient with normal kidney function
- 10% to 40% with underlying of renal insufficiency
- 用人話講：如果腎功能正常的話，200人才會有一個；如果不正常，大概10個人就會有一個
- Risk factors: CKD, DM, CHF, age, hypotension, ↑ contrast volume (JACC 2004;44:1393)
Pathophysiology
- compromised renal blood flow
- alterations in the meabolism of nitric oxide, adenosine, ageiotensin II and prostaglandins
- osmotic diuresis, increase renal metabolic activiy and oxygen consumption
- contrast stimulate a rapid influx of 胞外鈣；讓血管收縮
- 自由基；讓血流不好
- high osmotic results in reduction of renal blood flow