Acute Kidney Injury After Angiography Increases Long-Term Complications

Acute kidney injury (AKI) after coronary angiography raises the risk of long-term mortality, end-stage renal disease, and hospitalization for cardiovascular and renal events, according to a study published online January 7, 2011, ahead of print in Circulation.

Matthew T. James, MD, of the University of Alberta (Edmonton, Canada), and colleagues studied the outcomes of 14,782 patients who underwent coronary angiography between 2004 and 2006 and were enrolled in the Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease (APPROACH) database.

Of this cohort, 7.4% of patients experienced stage 1 AKI, while 2.2% had stage 2 or 3. Over a median follow-up of 19.7 months, overall 7.5% of patients died, 0.6% progressed to end-stage renal disease requiring renal replacement therapy, and 42.1% were rehospitalized.

In Cox regression models, the degree of AKI severity was associated with increasing risk of complications, including mortality, progression to end-stage renal disease, and cardiovascular and renal-specific hospitalizations. For example, compared with patients without AKI, those with stage 1 AKI had a twofold higher risk of death, while those with stage 2 or 3 AKI had an almost 4-fold increased risk. The risk of end-stage renal disease was most sharply affected by stage 2 or 3 AKI, which imparted an elevenfold increased risk. Meanwhile, risks of rehospitalization for heart failure and subsequent acute renal failure also rose with increasing AKI severity, while MI hospitalization risk was greater only with stage 1 AKI (table 1).

Table 1. Adjusted Outcomes by AKI Severity

 

HR (95% CI)

Mortality

   AKI Stage 1
  
AKI Stage 2/3

 

2.00 (1.69-2.36)
3.72 (2.92-4.76)

End-Stage Renal Disease

   AKI Stage 1
  
AKI Stage 2/3

 

4.15 (2.32-7.42)
11.74 (6.38-21.59)

Heart Failure Hospitalization

   AKI Stage 1
  
AKI Stage 2/3

 

1.48 (1.16-1.91)
2.17 (1.49-3.15)

Acute Renal Failure Hospitalization

   AKI Stage 1
  
AKI Stage 2/3

 

2.25 (1.71-2.96)
5.08 (3.41-7.58)

MI Hospitalization

   AKI Stage 1
  
AKI Stage 2/3

 

1.47 (1.12-1.91)
1.19 (0.70-2.02)

 
Based on these findings, the researchers note that “the presence and severity of AKI after coronary angiography could be used to help identify high-risk patients and to guide further management.”

Long-term Data, Hospitalization Specifics New

While “several previous studies have shown in-hospital events associated with AKI after coronary angiography, this study expands the literature by examining long-term events including cardiovascular and [renal] outcomes,” Dr. James pointed out in an e-mail communication with TCTMD. 

This AKI research appears to be “the first to separate out what happens to patients in terms of rehospitalization according to disease category,” Peter A. McCullough, MD, MPH, of Providence Park Heart Institute (Novi, MI), told TCTMD in a telephone interview, explaining that prior studies always reported data in terms of all-cause hospitalization.

Although this study adds support to AKI’s role in contributing to several long-term adverse outcomes, further research needs to demonstrate “that if you prevent kidney injury, it will help prevent mortality and rehospitalization,” Richard J. Solomon, MD, of the University of Vermont College of Medicine (Burlington, VT), cautioned in a telephone interview with TCTMD.

Preventing Kidney Injury 

The mainstay for AKI prevention is identifying patients who are at highest risk of the condition and giving them intravenous fluid, said Dr. Solomon, explaining that “this helps to wash the contrast out of the body quickly.”

Other preventative measures, including antioxidants such as acetylcysteine or bicarbonate and vasodilators, are still being studied, he noted.

AKI Management 

Current management following AKI development is “mainly supportive care and includes balancing fluid and metabolic status, avoiding further drugs with toxicity to the kidneys, and maintaining nutrition,” Dr. James said. “When severe kidney injury occurs, dialysis treatment may be required.” 

Dr. Solomon noted that the best approach to long-term care is to manage blood pressure, cholesterol levels, and comorbidities such as diabetes and to ensure that smoking cessation is addressed, if needed. “Intense management of all of the patient's cardiovascular risk factors is recommended,” he said. 

Study Details 

AKI was defined on the basis of changes in serum creatinine concentration from baseline to the peak level observed within 1 week of angiography (or before CABG if that was performed within 7 days of angiography) and categorized according to AKI Network criteria. 

Angiography was performed using nonionic iodinated radiocontrast agents with the choice of low- or iso-osmolar media, and use of prophylactic strategies, including N-acetylcysteine and intravenous fluid, at the discretion of treating physicians. 

 


Source:
Circulation

James MT, Ghali WA, Knudtson ML, et al. Associations between acute kidney injury and cardiovascular and renal outcomes after coronary angiography.. 2011;123:409-416.

 

Disclosures:

 

  • The study was supported by the Kidney Foundation of Canada and the Alberta Kidney Disease Network.
  • Drs. James, McCullough, and Solomon report no relevant conflicts of interest.

 

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Acute Kidney Injury After Angiography Increases Long-Term Complications

Acute kidney injury (AKI) after coronary angiography raises the risk of long term mortality, end stage renal disease, and hospitalization for cardiovascular and renal events, according to a study published online January 7, 2011, ahead of print in Circulation. Matthew

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