High-dose contrast agent administration during complex coronary angioplasty

Effects of a High Dose of the Contrast Medium Iodixanol on Renal Function in Patients Following Percutaneous Coronary Intervention

Iodixanol is associated with lower rates of contrast-induced acute kidney injury (CI-AKI). However, the effects of high volumes of iodixanol on renal function after percutaneous coronary intervention (PCI) have not been fully elucidated. This study evaluates the effects of high-dose (>300 mL) iodixanol on renal function within 72 hours of PCI. We retrospectively reviewed 676 consecutive patients who received high-dose (>300 mL) iodixanol during PCI between October 2015 and December 2017 in 4 centers. Logistic regression analysis was used to identify significant independent predictors for CI-AKI. The incidence of CI-AKI was 3.5% (23/651). In patients administered 300 to 500 mL and >500 mL iodixanol, the incidence of CI-AKI was 3.9% and 1.7%, respectively. In patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², the incidence of CI-AKI was 2.6%. In high-risk and very high-risk patients, stratified by the Mehran risk score, the incidence of CI-AKI was 3.3% and 4.3%, respectively. In patients received high-dose iodixanol (>300 mL), logistic regression analysis demonstrated that female sex, chronic kidney disease, and eGFR were independent risk factors for CI-AKI, but contrast volume was not. The administration of high (300-500 mL) and very high (>500 mL) dose of iodixanol is associated with low rates of CI-AKI.

Impact of cardiac catheterization timing and contrast media dose on acute kidney injury after cardiac surgery

BACKGROUND

The association between pre-operative cardiac catheterization and cardiac surgery associated acute kidney injury (CSA-AKI) has been reported inconsistently. The purpose of this study is to evaluate the effect of the catheterization timing and contrast media dose on the incidence of postoperative acute kidney injury.

METHODS

Patients who underwent cardiac catheterization and cardiac surgery successively from January 2015 to December 2015 were prospectively enrolled in this study. The primary outcome was CSA-AKI which was defined as the Kidney Disease: Improving Global Outcomes Definition and Staging (KDIGO) criteria. Univariate analysis and multivariate regression were performed to identify the predictors for CSA-AKI. Baseline characteristics were balanced with propensity score method for better adjustment.

RESULTS

A total of 1069 consecutive eligible patients were enrolled into this study. The incidence of CSA-AKI and AKI requiring renal replacement therapy (AKI-RRT) were 38.5% (412/1069) and 1.9% (20/1069) respectively. Preoperative estimated glomerular filtration rate less than 60 mL/min/1.73m² (OR = 2.843 95% CI 1.374-5.882), the time interval between catheterization and surgery≤7 days (OR = 2.546, 95% CI 1.548-4.189) and the dose of contrast media (CM) > 240 mg/kg (OR = 2.490, 95%CI 1.392-4.457) were identified as predictors for CSA-AKI. In the patients with the dose of CM > 240 mg/kg, the incidence of CSA-AKI was higher in patients who underwent cardiac catheterization ≤7 days before cardiac surgery than in those of > 7 days before cardiac surgery (39.4% vs. 28.8%, p = 0.025). The longer interval of more than 7 days was revealed to be inversely associated with CSA-AKI through logistic regression (OR = 0.579, 95% CI 0.337-0.994).

CONCLUSION

Catheterization within 7 days of cardiac surgery and a dose of CM > 240 mg/kg were associated with the onset of CSA-AKI. For patients who received a dose of CM > 240 mg/kg, postponing the cardiac surgery is potentially beneficial to reduce the risk of CSA-AKI.

Contrast-induced nephropathy: Basic concepts, pathophysiological implications and prevention strategies

Contrast-induced nephropathy (CIN) is reversible acute renal failure observed following administration of iodinated contrast media (CM) during angiographic or other medical procedures such as urography. There are various mechanisms through which CM develop their nephrotoxic effects, including oxidative stress and apoptosis. CIN is a real-life, albeit not very rare, entity. Exact pathophysiology remains obscure and no standard diagnostic criteria apply. The Acute Kidney Injury Network criteria was recently employed but its incidence/clinical significance warrants further clarification based on recent methodological advancements, because most published studies to date were contaminated by bias. The current study is a comprehensive review conducted to provide an overview of the basic concepts of CIN and summarize recent knowledge on its pathophysiology and the evidence supporting potential prevention strategies. CIN is expected to increase morbidity, hospital stay and mortality, while all patients scheduled to receive CM should undergo risk assessment for CIN and high-risk patients may be considered candidates for prevention strategies. The value of using compounds with antioxidant properties other than sodium bicarbonate, remains controversial, warranting further clinical investigation.

Contrast-induced acute kidney injury in interventional cardiology: Emerging evidence and unifying mechanisms of protection by remote ischemic conditioning

Contrast-induced acute kidney injury (CI-AKI) is a common complication of many diagnostic and therapeutic cardiovascular procedures. It is associated with longer in-hospital stay, more complicated hospitalization course, and higher in-hospital morbidity and mortality. With increasing use of contrast media in various diagnostic and interventional procedures, the prevalence of CI-AKI is expected to rise. Although pre-hydration with intravenous normal saline is recommended in patients with elevated risk of CI-AKI, this approach is often not feasible in many clinical settings. Remote ischemic conditioning (RIC), elicited by application of one or more, brief, non-injurious episodes of ischemia and reperfusion of a limb, is a promising therapy for preventing or attenuating the deleterious effects of contrast media on the kidney. Although the mechanisms of protection by RIC have not been completely defined, complex humoral, neural, and inflammatory pathways have been hypothesized to be in play. Given that RIC is non-invasive and cheap, it is attractive from clinical and economic perspective as a therapy to protect the kidney from CI-AKI. In this succinct review, we highlight the unifying mechanisms of CI-AKI and provide an overview of proposed biological mechanisms of renal protection by RIC. Emerging pre-clinical and clinical evidence in interventional cardiology is also discussed.

Sodium Bicarbonate-Ascorbic Acid Combination for Prevention of Contrast-Induced Nephropathy in Chronic Kidney Disease Patients Undergoing Catheterization

BACKGROUND

Sodium bicarbonate and ascorbic acid have been proposed to prevent contrast-induced nephropathy (CIN). The present study evaluated the effect of their combined use on CIN incidence.

METHODS AND RESULTS

We prospectively enrolled 429 patients with chronic kidney disease (CKD: baseline estimated glomerular filtration rate <60 mL/min/1.73 m2) prior to elective coronary catheterization. CIN was defined as absolute (≥0.5 mg/dL) or relative (≥25%) increase in serum creatinine within 72 h. In the saline hydration (n=218) and combined sodium bicarbonate+ascorbic acid (n=211) groups, a total of 1,500-2,500 mL 0.9% saline was given before and after the procedure. In addition, the combination group received 20 mEq sodium bicarbonate and 3 g ascorbic acid i.v. before the procedure, followed by 2 g ascorbic acid after the procedure and a further 2 g after 12 h. There were no significant differences between the basic characteristics and contrast volume in the 2 groups. CIN occurred in 19 patients (8.7%) in the saline group, and in 6 patients (2.8%) in the combined treatment group (P=0.008).

CONCLUSIONS

Combined sodium bicarbonate and ascorbic acid could prevent CIN following catheterization in CKD patients.

Prevention of contrast-induced acute kidney injury after percutaneous coronary intervention for chronic total coronary occlusions

Chronic total occlusions (CTOs) represent a major challenge in percutaneous coronary revascularization. The recent advances in strategies and techniques and the development of dedicated equipment, such as microcatheters and wires, have resulted in considerably higher success rates. Although successful CTO recanalization is associated with significant clinical benefits, including improvement of angina, quality of life, reduced need for surgical revascularization, and improvement of left ventricular function, CTO procedures may require prolonged x-ray exposure and use of larger volumes of contrast compared with non-CTO procedures. Large volumes of contrast medium have been associated with increased rates of contrast-induced acute kidney injury (CI-AKI) and adverse short- and long-term outcomes. Application of specific measures and algorithms should be considered by all CTO operators to prevent CI-AKI.

The role of inflammation in contrast-induced nephropathy

Objective:

Global incidence of contrast-induced nephropathy (CIN) is 2–5%, but a recent Kenyan study highlighted a local incidence of 12–14% without offering an explanation for the higher incidence. This study proposes that inflammatory states confer a higher relative risk for development of CIN. Our objective was to determine the risk of developing CIN given the presence of an inflammatory state in patients in Kenya.

Methods:

Prospective cohort study of patients undergoing a contrast-enhanced CT (CECT) scan in a private university teaching hospital in Kenya and having no known risk factors for CIN. 423 patients were recruited and grouped into those without inflammation (unexposed) having serum C-reactive protein (CRP) levels ≤5 mg dl⁻¹ and those with evidence of inflammation having CRP levels >5 mg dl⁻¹. Serum creatinine (SCr) was measured before the CECT and 48 h following the CECT with CIN diagnosed by an increase of >25% in the SCr from the baseline. Relative risk was determined and multiple logistic regression analysis performed on biophysical variables and contrast volume to assess their effect on development of CIN.

Results:

Patients with high CRP levels had a relative risk of developing CIN of 2.16 compared with those with normal levels of CRP (p = 0.016). No statistically significant association was seen between biophysical variables or volume of contrast and development of CIN.

Conclusion:

Ongoing inflammation doubles the likelihood of development of CIN.

Advances in knowledge:

This study highlights the importance of inflammation as a risk factor in the development of CIN.

Temporal trends of fluoroscopy time and contrast utilization in coronary chronic total occlusion revascularization: insights from a multicenter United States registry

BACKGROUND

The impact of operator experience on fluoroscopy time and contrast utilization during percutaneous coronary intervention (PCI) of coronary chronic total occlusions (CTOs) has received limited study.

METHODS

We evaluated temporal trends in fluoroscopy time and contrast utilization among 1,363 consecutive CTO PCIs performed at three US institutions between January 2006 and November 2011.

RESULTS

Mean age was 65 ± 11 years, 85% of patients were men, 40% had diabetes, 37% had prior coronary artery bypass graft surgery, and 42% had prior PCI. The CTO target vessel was the right coronary artery (55%), circumflex (23%), left anterior descending artery (21%), and left main or bypass graft (1%). The retrograde approach was used in 34% of all procedures. The technical and procedural success rates were 85.5 and 84.2%, respectively. The mean procedural time, fluoroscopy time, and contrast utilization were 113 ± 61 min, 42 ± 29 min, and 294 ± 158 mL, respectively. Years since initiation of CTO PCI were independently associated with higher technical success rate (odds ratio [OR] = 1.52, 95% confidence interval [CI] = 1.52-1.70, P < 0.001), lower fluoroscopy time (OR = 0.84, 95% CI = 0.75-0.95, P = 0.005), and contrast utilization (OR = 0.84, 95% CI = 0.62-0.79, P < 0.001) during the study period.

CONCLUSIONS

Among selected US-based institutions performing CTO PCI, we observed a significant reduction in total fluoroscopy time and contrast utilization paralleled with an improved technical success rate over time.

Clinical predictors of contrast-induced acute kidney injury in patients undergoing emergency versus elective percutaneous coronary intervention

BACKGROUND

To evaluate the incidence and clinical predictors of contrast-induced acute kidney injury (CI-AKI) in patients with ST-segment elevation myocardial infarction (STEMI), unstable angina pectoris/non-STEMI (UAP/NSTEMI), and stable AP (SAP) undergoing percutaneous coronary intervention (PCI).

METHODS AND RESULTS

We enrolled 1,954 patients (SAP, n=1,222; UAP/NSTEMI, n=277; STEMI, n=455) who underwent PCI. Patients were categorized according to contrast media volume/estimated glomerular filtration rate ratio (CV/eGFR low: <2.0, mid: 2.0-2.9, high: ≥3.0). CI-AKI was defined as an increase in serum creatinine of 0.5mg/dl or 25% within 1 week from contrast-medium injection. The incidence of CI-AKI was highest among the STEMI patients (SAP, 4.24%; UAP/NSTEMI, 10.7%; STEMI, 16.1%, P<0.01). Significant predictors of CI-AKI were emergency PCI (odds ratio [OR] 3.70; 95% confidence interval [CI] 2.55-5.37; P<0.001), ejection fraction <40% (OR 2.04; 95% CI 1.24-3.36; P=0.005), and hemoglobin <10g/dl (OR 0.02; 95% CI 1.17-4.55; P=0.02) after multivariate logistic regression analysis. In the SAP group, a CV/eGFR ratio ≥3.0 was a significant predictor of CI-AKI (P=0.048), but not in UAP/NSTEMI and STEMI patients.

CONCLUSIONS

UAP/NSTEMI and STEMI patients undergoing emergency PCI were at high risk for CI-AKI regardless of CV/eGFR ratio. Minimizing the dose of contrast medium based on eGFR might be valuable in reducing the risk of CI-AKI in SAP patients.

Using DynaCT for the assessment of ilio-femoral arterial calibre, calcification and tortuosity index in patients selected for trans-catheter aortic valve replacement

Adequate vascular access for femoral trans-catheter aortic valve replacement is fundamental to the success of the procedure. Assessment of vascular calibre, tortuosity and calcification is performed by angiography and multi-slice computed tomography (MSCT). Can DynaCT provide the same information as MSCT? 15 Patients underwent MSCT, angiography and DynaCT. Vessel diameter measurements were taken in three positions of the left and right ilio-femoral arteries. Tortuosity was assessed using an index of the direct distance and the distance taken by the artery between two points. Calcification was assessed in MSCT and DynaCT using a simple scoring system. Concordance correlation coefficient of arterial calibre between angiography and MSCT was 0.96 (95 % CI 0.94-0.97). DynaCT and angiography was 0.94 (95 % CI 0.91-0.96) and Dyna CT and MSCT, 0.95 (95 % CI 0.92-0.97). Bland-Altman tests demonstrate a mean difference between the angiogram and the MSCT of 0.06 mm (+0.97, -1.42), angiogram and DynaCT, 0.13 mm, (+1.00, -0.87), DynaCT and MSCT, 0.2 mm, (+1.15, -0.76). Tortuosity comparisons gave a median tortuosity index for MSCT 1.29 and DynaCT 1.23 (p = 0.472). Calcification comparisons of MSCT and DynaCT using correlation coefficients demonstrate a correlation of 0.245 (p = 0.378). Effective radiation doses were: DynaCT; 3.63 ± 0.65 mSv and angiography; 0.57 ± 0.72 mSv, MSCT; 7.15 ± 2.58 mSv. DynaCT is equal to MSCT and angiography in assessing femoral artery calibre. Like MSCT, it can assess tortuosity and can produce 3D images but is inferior in the assessment of calcification.

GRACE risk score predicts contrast-induced nephropathy in patients with acute coronary syndrome and normal renal function

We evaluated the incidence, clinical predictors, and outcomes of contrast-induced nephropathy (CIN) after coronary angiography in patients with myocardial infarction and normal kidney function. We studied 202 consecutive patients with glomerular filtration rate >60 mL/min/1.73 m(2). The CIN was defined according to 3 definitions: increases in serum creatinine (sCr) ≥25%, ≥0.3 mg/dL, and ≥0.5 mg/dL. The CIN occurred in 56 (27.7%), 42 (20.8%), and 13 (6.4%) patients, respectively. In multivariate analysis, the presence of a high Global Registry of Acute Coronary Events (GRACE) risk score (>140) was an independent predictor of CIN in its milder forms (≥25% and ≥0.3 mg/dL of rise in sCr). Increase in sCr ≥0.3 mg/dL was an independent predictor of bleeding. Increase in sCr ≥0.5 mg/dL was an independent predictor of in-hospital cardiac events (mortality, myocardial infraction [MI], and heart failure). As conclusion, the GRACE score is a useful tool to predict CIN in patients with MI and normal renal function.

Novel use of the GuideLiner catheter to minimize contrast use during PCI in a patient with chronic kidney disease

The GuideLiner catheter (Vascular Solutions, Minneapolis, MN) is a rapid-exchange "mother and child" guide extension that increases support in complex percutaneous coronary intervention (PCI). While this device was primarily designed to facilitate balloon and stent delivery, we describe the use of this device to reduce contrast volume through sub-selective visualization in a patient with chronic kidney disease (CKD) undergoing PCI of the left coronary system.

Renal function-based contrast dosing to define safe limits of radiographic contrast media in patients undergoing percutaneous coronary interventions

OBJECTIVES

The aim of this study was to evaluate the association between calculated creatinine clearance (CCC)-based contrast dose and renal complications in patients undergoing percutaneous coronary interventions (PCI).

BACKGROUND

Excess volumes of contrast media are associated with renal complications in patients undergoing cardiac procedures. Because contrast media are excreted by the kidney, we hypothesized that a dose estimation on the basis of CCC would provide a simple strategy to define a safe dose of contrast media.

METHODS

We assessed the association between CCC-based contrast dose and the risk of contrast-induced nephropathy (CIN) and need for in-hospital dialysis in 58,957 patients undergoing PCI and enrolled in the BMC2 (Blue Cross Blue Shield of Michigan Cardiovascular Consortium) registry from 2007 to 2008. Patients receiving dialysis at the time of the procedure were excluded.

RESULTS

The risk of CIN and nephropathy requiring dialysis (NRD) was directly associated with increasing contrast volume adjusted for renal function. The risk for CIN and NRD approached significance when the ratio of contrast dose/CCC exceeded 2 (adjusted odds ratio [OR] for CIN: 1.16, 95% confidence interval [CI]: 0.98 to 1.37, adjusted OR for NRD: 1.72, 95% CI: 0.9 to 3.27) and was dramatically elevated in patients exceeding a contrast to CCC ratio of 3 (adjusted OR for CIN: 1.46, 95% CI: 1.27 to 1.66, adjusted OR for NRD: 1.89, 95% CI: 1.21 to 2.94).

CONCLUSIONS

Our study supports the need for minimizing contrast dose in patients with renal dysfunction. A contrast dose on the basis of estimated renal function with a planned contrast volume restricted to less than thrice and preferably twice the CCC might be valuable in reducing the risk of CIN and NRD.

Contrast-induced nephropathy in interventional cardiology

Development of contrast-induced nephropathy (CIN), ie, a rise in serum creatinine by either ≥0.5 mg/dL or by ≥25% from baseline within the first 2-3 days after contrast administration, is strongly associated with both increased inhospital and late morbidity and mortality after invasive cardiac procedures. The prevention of CIN is critical if long-term outcomes are to be optimized after percutaneous coronary intervention. The prevalence of CIN in patients receiving contrast varies markedly (from <1% to 50%), depending on the presence of well characterized risk factors, the most important of which are baseline chronic renal insufficiency and diabetes mellitus. Other risk factors include advanced age, anemia, left ventricular dysfunction, dehydration, hypotension, renal transplant, low serum albumin, concomitant use of nephrotoxins, and the volume of contrast agent. The pathophysiology of CIN is likely to be multifactorial, including direct cytotoxicity, apoptosis, disturbances in intrarenal hemodynamics, and immune mechanisms. Few strategies have been shown to be effective to prevent CIN beyond hydration, the goal of which is to establish brisk diuresis prior to contrast administration, and to avoid hypotension. New strategies of controlled hydration and diuresis are promising. Studies are mixed on whether prophylactic oral N-acetylcysteine reduces the incidence of CIN, although its use is generally recommended, given its low cost and favorable side effect profile. Agents which have been shown to be ineffective or harmful, or for which data supporting routine use do not exist, include fenoldopam, theophylline, dopamine, calcium channel blockers, prostaglandin E(1), atrial natriuretic peptide, statins, and angiotensin-converting enzyme inhibitors.

Contrast-induced nephropathy in patients undergoing percutaneous coronary intervention

Contrast Induced Nephropathy (CIN) is a feared complication of numerous radiological procedures that expose patients to contrast media. The most notorious of these procedures is percutaneous coronary intervention (PCI). Not only is this a leading cause of morbidity and mortality, but it also adds to increased costs in high risk patients undergoing PCI. It is thought to result from direct cytotoxicity and hemodynamic challenge to renal tissue. CIN is defined as an increase in serum creatinine by either ≥0.5 mg/dL or by ≥25% from baseline within the first 2-3 days after contrast administration, after other causes of renal impairment have been excluded. The incidence is considerably higher in diabetics, elderly and patients with pre-existing renal disease when compared to the general population. The nephrotoxic potential of various contrast agents must be evaluated completely, with prevention as the mainstay of focus as no effective treatment exists. The purpose of this article is to examine the pathophysiology, risk factors, and clinical course of CIN, as well as the most recent studies dealing with its prevention and potential therapeutic interventions, especially during PCI. The role of gadolinium as an alternative to iodinated contrast is also discussed.

The relative renal safety of iodixanol compared with low-osmolar contrast media: a meta-analysis of randomized controlled trials

OBJECTIVES

We sought to compare the nephrotoxicity of the iso-osmolar contrast medium, iodixanol, to low-osmolar contrast media (LOCM).

BACKGROUND

Contrast-induced acute kidney injury (CI-AKI) is a common cause of in-hospital renal failure. A prior meta-analysis suggested that iodixanol (Visipaque, GE Healthcare, Princeton, New Jersey) was associated with less CI-AKI than LOCM, but this study was limited by ascertainment bias and did not include the most recent randomized controlled trials.

METHODS

We searched Medline, Embase, ISI Web of Knowledge, Google Scholar, Current Contents, and International Pharmaceutical Abstracts databases, and the Cochrane Central Register of Controlled Trials from 1980 to November 30, 2008, for randomized controlled trials that compared the incidence of CI-AKI with either iodixanol or LOCM. Random-effects models were used to calculate summary risk ratios (RR) for CI-AKI, need for hemodialysis, and death.

RESULTS

A total of 16 trials including 2,763 subjects were pooled. There was no significant difference in the incidence of CI-AKI in the iodixanol group than in the LOCM group overall (summary RR: 0.79, 95% confidence interval [CI]: 0.56 to 1.12, p = 0.19). There was no significant difference in the rates of post-procedure hemodialysis or death. There was a reduction in CI-AKI when iodixanol was compared with ioxaglate (RR: 0.58, 95% CI: 0.37 to 0.92; p = 0.022) and iohexol (RR: 0.19, 95% CI: 0.07 to 0.56; p = 0.002), but no difference when compared with iopamidol (RR: 1.20, 95% CI: 0.66 to 2.18; p = 0.55), iopromide (RR: 0.93, 95% CI: 0.47 to 1.85; p = 0.84), or ioversol (RR: 0.92, 95% CI: 0.60 to 1.39; p = 0.68).

CONCLUSIONS

This meta-analysis including 2,763 subjects suggests that iodixanol, when compared with LOCM overall, is not associated with less CI-AKI. The relative renal safety of LOCM compared with iodixanol may vary based on the specific type of LOCM.

Choice of contrast medium in patients with impaired renal function undergoing percutaneous coronary intervention

BACKGROUND

No clinical trial has yet focused on contrast-mediated nephrotoxicity in patients with chronic renal failure exclusively undergoing percutaneous coronary intervention (PCI). Therefore, the aim of this study was to compare the effect of contemporary contrast media on nephrotoxicity in this high-risk patient population.

METHODS AND RESULTS

This prospective, randomized, double-blind, comparative clinical trial randomly selected 939 patients with chronic renal failure undergoing coronary angiography with potential PCI to receive either the iso-osmolar contrast medium iodixanol or the low-osmolar contrast medium iomeprol. Of those 939 patients, 615 received diagnostic angiography only and were not included in the primary study analysis, but were followed up in a registry. Three hundred twenty-four patients underwent PCI, of which one-half received iodixanol or iomeprol, respectively, and were included in the primary study analysis. The primary end point was the peak increase in S-creatinine during hospitalization for PCI. Maximum increase in S-creatinine after PCI was lower than expected and thus impaired the power of the study. It was not significantly different between the 2 contrast groups (0.19+/-0.40 mg/dL for iodixanol and 0.21+/-0.34 mg/dL for iomeprol; P=0.53). Albeit contrast media-induced nephropathy rates were lower with iodixanol (22.2% compared with 27.8% for iomeprol), this difference was not statistically different (P=0.25). Subgroup analysis suggested a favorable outcome regarding nephrotoxicity in patients who received higher contrast volumes (>340 mL) in the iodixanol group (P(interaction)=0.016).

CONCLUSIONS

Routine use of iso-osmolar contrast medium is not associated with a significant reduction of nephrotoxicity compared with low-osmolar contrast medium in patients with chronic renal failure undergoing PCI. However, a positive effect was seen in the iso-osmolar contrast group for patients receiving high amounts of contrast medium, which awaits confirmation of a specifically designed randomized clinical trial. Clinical Trial Registration- clinicaltrials.gov Identifier: NCT00390585.

Contrast-induced nephropathy

Contrast induced nephropathy (CIN) is an iatrogenic disorder, resulting from exposure to contrast media. Contrast-induced hemodynamic and direct cytotoxic effects on renal structures are highly evident in its pathogenesis, whereas other mechanisms are still poorly understood. CIN is typically defined as an increase in serum creatinine by either > or =0.5 mg/dl or by > or =25% from baseline within the first 2-3 days after contrast administration. Although rare in the general population, CIN has a high incidence in patients with an underlying renal disorder, in diabetics, and the elderly. The risk factors are synergistic in their ability to produce CIN. The best way to prevent CIN is to identify the patients at risk and to provide adequate peri-procedural hydration. The role of various drugs in prevention of CIN is still controversial and warrants future studies. Despite remaining uncertainty regarding the degree of nephrotoxicity produced by various contrast agents, in current practice non-ionic low-osmolar contrast media are preferred over the high-osmolar contrast media in patients with renal impairment.

Contrast-induced nephropathy: definition, epidemiology, and patients at risk

Radiological procedures utilizing intravascular iodinated contrast media injections are being widely applied for both diagnostic and therapeutic purposes. This has resulted in an increasing incidence of procedure-related contrast-induced nephropathy (CIN). The definition of CIN includes absolute (> or = 0.5 mg/dl) or relative increase (> or = 25%) in serum creatinine at 48-72 h after exposure to a contrast agent compared to baseline serum creatinine values, when alternative explanations for renal impairment have been excluded. Although the risk of renal function impairment associated with radiological procedures is low (0.6-2.3%) in the general population, it may be very high in selected patient subsets (up to 20%), especially in patients with underlying cardiovascular disease. This review provides information on the known risk factors for the development of CIN, and completes with describing user-friendly CIN risk score based on the readily available information.

Contrast nephropathy after coronary angiography

Contrast nephropathy after coronary angiography is associated with considerable morbidity and mortality. We discuss the incidence, definition, and pathologic mechanisms of contrast nephropathy; provide an overview of risk factors; highlight proven preventive interventions; clarify which interventions have shown no benefit; and discuss future possibilities. The prevention of contrast nephropathy is crucial for the care of patients undergoing coronary angiography and should be possible with an understanding of risk factors and proven management strategies.

Predicting renal failure after balloon angioplasty in high-risk patients

PURPOSE

To assess the incidence and predictors of acute renal failure after percutaneous transluminal angioplasty (PTA) in a cohort of patients with generalized atherosclerosis.

METHODS

A retrospective review of 213 consecutive patients (127 men; median age 71 years, interquartile range 63-77) undergoing femoropopliteal PTA was undertaken. Renal function was measured by creatinine clearance at baseline and 24 hours after the intervention; acute renal dysfunction was defined as > or = 20% decrease of creatinine clearance. The predictive value of potential risk factors was determined in a multivariate model adjusting for comorbidities, pre-existing renal impairment, and angiographic data.

RESULTS

Overall serum creatinine values and creatinine clearance remained stable within 24 hours after PTA. Acute renal dysfunction occurred in 25 (12%) patients. Two (1%) patients developed oliguria; one required transient hemodialysis and developed persistent renal failure. Pre-existing impaired renal function (OR 12.2, p < 0.0001) and contrast dosage (OR 1.1, p = 0.03) were independent predictors of acute renal failure; hypertension (OR 7.9, p = 0.06) and congestive heart failure (OR 4.5, p = 0.06) were associated factors.

CONCLUSIONS

While transient acute renal dysfunction occurs in approximately 10% of patients with peripheral artery disease within 24 hours after angioplasty, persistent renal failure or end-stage renal disease is rare.

Five French (5 Fr) guiding catheters for percutaneous coronary angioplasty and stent placement: An initial feasibility study

Thirty patients were treated with percutaneous coronary intervention (PCI) using a 5 Fr guiding catheter. A recently developed, mechanically advantaged hand injector was used to deliver contrast and achieved excellent visualization through the 5 Fr system. Stent sizes ranged from 2.25 to 4.00 mm in diameter and from 8 to 24 mm in length. All primary lesions were successfully treated. The average contrast use was 70 cc per case. There were no major complications and only one minor femoral hematoma. In selected patients, a balloon angioplasty and stent placement can be performed safely and successfully with 5 Fr guiding catheters using currently available products. This technique creates a smaller arterial puncture site, which may obviate the need for a closure device and allow early and safe ambulation. With 5 Fr systems, it appears that contrast usage is reduced, thereby potentially decreasing cost and morbidity. Cathet. Cardiovasc. Intervent. 51:352-357, 2000.

Ad hoc coronary intervention

Ad hoc coronary intervention is a percutaneous revascularization procedure performed at the same sitting as diagnostic cardiac catheterization. While this appears to be an efficient strategy, the safety and cost of ad hoc coronary intervention compared with delayed coronary intervention have not been clearly documented. Special preparation and precautions are necessary for patients in whom ad hoc coronary intervention is anticipated. Ad hoc coronary intervention is not appropriate if informed consent has not been previously obtained or if it would pose greater risks than delayed intervention. While ad hoc coronary intervention is often efficient and effective, its use should be individualized. Cathet. Cardiovasc. Intervent. 49:130-134, 2000.

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.

One-stage coronary angiography and angioplasty

The combination of diagnostic angiography and angioplasty as a single procedure is becoming common practice in many institutions, but the feasibility and safety of this strategy have not been reported. This report describes 2,069 patients who underwent coronary angioplasty over a 3-year period at an institution where combined angiography and angioplasty is the norm. All patients were prepared before angiography for potential immediate angioplasty. In 1,719 patients, angioplasty was performed immediately after the diagnostic angiogram, while separate procedures were performed in 350 patients. Of those 350 patients, 254 were referred for angioplasty after diagnostic angiography at other hospitals. One thousand one hundred ninety-seven patients were admitted electively for treatment of stable angina pectoris, and 872 underwent procedures during hospitalization for unstable angina or acute myocardial infarction. One thousand nine hundred seven patients (92.2%) had successful angioplasties; in 130 patients (6.3%) the lesion could not be dilated, but no complication occurred, and in 32 patients (1.5%) angioplasty ended with a major complication (0.8% death, 1.0% Q-wave myocardial infarction, 0.5% emergency coronary artery bypass surgery). There was no difference between the combined and staged groups with regard to success, major and minor complication rates or in length of hospitalization after angioplasty. We conclude that routine combined strategy for angiography and angioplasty is feasible, safe, easier for the patient, and more cost-effective than 2 separate procedures.

Balloon catheter requirements during contemporary percutaneous transluminal coronary angioplasty

In order to examine the outcome of utilizing multiple balloon catheters during the percutaneous transluminal coronary angioplasty (PTCA), 300 consecutive PTCAs were analyzed. PTCA was performed in a single lesion in 163 patients (54%), in multiple lesions in 52 patients (18%), and in multiple vessels in 85 patients (28%). A total of 488 balloon catheters were used (1.6/case, range 1-9) and in 112 cases (37%) > or = 2 catheters were used. Multiple balloon catheters were needed in 27 single lesion (17%), 24 multilesion (48%), and 61 multivessel (72%) cases (p < .05). There was no difference in the angiographic success rate in cases completed with 1 balloon catheter (238/251, 95%) compared to those requiring > or = 2 catheters (260/274, 95%). Emergency bypass was required in 5 patients (1.7%) and there were 2 deaths (0.6%). Thus, although contemporary PTCA frequently requires multiple balloon catheters for completion, success rates remain high and appear to offset the increased procedural expenses.

Caring for patients after coronary intervention. Follow-up tips for primary care physicians

Primary care physicians may be faced with assessing patients after their return home from percutaneous transluminal coronary angioplasty (PTCA) or other coronary intervention. Familiarity with possible vascular, renal, and hematologic complications is important, and an open line of communication with the cardiologist who performed the procedure is essential. Restenosis can usually be identified by the return of symptoms or with exercise imaging studies. When restenosis is suspected, referral for consideration of a second PTCA is appropriate. Most patients enjoy an excellent long-term result after PTCA and can return to an active life-style. Primary care physicians play an important role in instituting and reinforcing plans for life-style changes that promote reduction in coronary atherosclerosis.

Catastrophic thrombus development despite systemic heparinization during coronary angioplasty: possible relationship to nonionic contrast

Two cases of catastrophic thrombus formation during coronary angioplasty occurred shortly after the operators began using nonionic contrast. This occurred despite systemic heparinization, the adequacy of which was documented by activated clotting times (ACT). Both cases were resistant to balloon inflation and one was refractory to intracoronary thrombolysis. There is a considerable body of evidence documenting that low-osmolality contrast media, especially those that are nonionic, have less anticoagulant effect than standard contrast media. Several reports have also been published suggesting possible relationships between nonionic contrast and intravascular thrombus formation during coronary angiography and angioplasty. These data are reviewed and recommendations made for utilization of these contrast media.

The adverse effects of angiographic radiocontrast media

Radiographic procedures which require the intravascular administration of water-soluble radiocontrast media are performed with increasing frequency. Each examination carries risks that are related either to the technique itself or to the opaque medium chosen. The pathogenesis of radiocontrast media-related adverse effects cannot be explained by a unique theory. The major factors implicated are direct chemotoxic effects and the physicochemical properties of contrast media, the latter being the basis for development of new contrast agents. With nonionic opaque media cardiovascular adverse effects, heat sensation and local pain are observed less frequently. However, it remains unclear whether the incidence of organ dysfunction or anaphylactic reactions with nonionic contrast media currently used can be reduced. This review compares ionic and nonionic contrast media, and current thoughts on the pathophysiology and treatment of adverse reactions are presented.