Incidence of acute renal failure in open heart surgery

Is radiocontrast-induced nephropathy avoidable? The scientific evidence in 2006

Due to the wide use of radiocontrast agents (RCA) in modern radiology and interventional cardiology, the incidence of radiocontrast-induced nephropathy (RCIN) is increasing. The risk factors for RCIN are primarily pre-existing (even mild) renal dysfunction, diabetes mellitus, absolute or relative hypovolemia, nephrotoxic drugs, etc., particularly in elderly patients. The presence of these risk factors seems to be more important than the type of contrast agent used. To date, there are several certainties and controversies in the prevention of RCIN. Hydration with normal saline and/or bicarbonate administration pre-and post-intervention is certainly useful. Though controversial, N-Acetylcysteine administration may be still advisable. Recent investigations showed the benefits of aminophylline/theophylline administration in RCA-induced renal tubular toxicity. Conventional hemodialysis cannot prevent RCIN, but may potentially aggravate renal dysfunction through hemodynamic instability. “High-flux” hemodialysis and hemodiafiltration may contribute efficiently to RCIN prevention, but systematic use of these modern dialysis techniques is limited by high costs and availability. The authors review — in a systematic manner, and in the perspective of evidence-based medicine — the most important data from literature concerning the prevention of RCIN.

Acute renal failure after coronary intervention: incidence, risk factors, and relationship to mortality

PURPOSE

This study set out to define the incidence, predictors, and mortality related to acute renal failure (ARF) and acute renal failure requiring dialysis (ARFD) after coronary intervention.

PATIENTS AND METHODS

Derivation-validation set methods were used in 1,826 consecutive patients undergoing coronary intervention with evaluation of baseline creatinine clearance (CrCl), diabetic status, contrast exposure, postprocedure creatinine, ARF, ARFD, in-hospital mortality, and long-term survival (derivation set). Multiple logistic regression was used to derive the prior probability of ARFD in a second set of 1,869 consecutive patients (validation set).

RESULTS

The incidence of ARF and ARFD was 144.6/1,000 and 7.7/1,000 cases respectively. The cutoff dose of contrast below which there was no ARFD was 100 mL. No patient with a CrCl > 47 mL/min developed ARFD. These thresholds were confirmed in the validation set. Multivariate analysis found CrCl [odds ratio (OR) = 0.83, 95% confidence interval (CI) 0.77 to 0.89, P <0.00001], diabetes (OR = 5.47, 95% CI 1.40 to 21.32, P = 0.01), and contrast dose (OR = 1.008, 95% CI 1.002 to 1.013, P = 0.01) to be independent predictors of ARFD. Patients in the validation set who underwent dialysis had a predicted prior probability of ARFD of between 0.07 and 0.73. The in-hospital mortality for those who developed ARFD was 35.7% and the 2-year survival was 18.8%.

CONCLUSION

The occurrence of ARFD after coronary intervention is rare (<1%) but is associated with high in-hospital mortality and poor long-term survival. Individual patient risk can be estimated from calculated CrCl, diabetic status, and expected contrast dose prior to a proposed coronary intervention.

A comparison of fenoldopam and nitroprusside in the control of hypertension following coronary artery surgery

A prospective trial to compare the effects of the synthetic dopaminergic (DA1) agonist, fenoldopam (FEN), with sodium nitroprusside (SNP) for control of blood pressure following coronary artery bypass graft surgery was carried out in 20 patients. Patients were randomly allocated to receive either FEN or SNP when the systolic arterial blood pressure (SAP) rose above 130 mmHg. The goal of therapy was to achieve a stable control of blood pressure below 130 mmHg at a level at least 25 mmHg below the pretreatment value. Treatment was then continued for 2 hours. Hemodynamic measurements were made before treatment, after stable control of blood pressure had been achieved, and thereafter at 30, 60, and 120 minutes. Urine output, sodium, potassium, and creatinine clearance were also measured during the study. Both SNP and FEN caused a rapid and significant fall in SAP (P < 0.001) and a fall in systemic vascular resistance (P < 0.001). FEN caused an increase in cardiac index (P < 0.001) and in stroke volume (P < 0.001) in contrast to SNP. Urine output and potassium clearance fell with SNP (P < 0.05) in contrast to FEN. Thus, FEN would appear to control SAP as effectively as SNP, but may have more beneficial effects on cardiac output and some aspects of renal function.