Single versus bilateral internal thoracic artery grafting in patients with impaired renal function.

OBJECTIVE: The optimal strategy for surgical revascularization in patients with impaired renal function is inconclusive. We compared early and late outcomes between bilateral internal thoracic artery (BITA) and single ITA (SITA) grafting in patients with renal dysfunction. METHODS: This is a retrospective analysis of all the patients with multivessel disease and impaired renal function (estimated glomerular filtration rate <60mL/min/1.73m2) who underwent isolated coronary artery bypass graft (CABG) in our center during 1996-2011, utilizing either BITA or SITA revascularization. RESULTS: Of the 5301 patients with multivessel disease who underwent surgical revascularization during the study period, 391 were with impaired renal function: 212 (54.2%) underwent BITA, 179 (45.8%) underwent SITA. Patients who underwent BITA were less likely to have comorbidities. Statistically significant differences were not observed between the BITA and SITA groups in 30-day mortality (5.6% vs. 9.0%, p = 0.2) and in rates of early stroke, myocardial infarction, and sternal infection (4.5% vs. 6.1%, p = 0.467; 1.7% vs. 2.8%, p = 0.517; and 2.2% vs. 5.7%, p = 0.088, respectively). Long-term survival of the BITA group was better: median 8.36 vs. 4.14 years, p<0.001. In multivariable analysis, BITA revascularization was associated with decreased late mortality (HR = 0.704, 95% CI: 0.556-0.89, p = 0.003). In analysis of a matched cohort (134 pairs), early outcomes did not differ between the groups; however, in multivariable analysis, BITA revascularization was associated with decreased late mortality (HR = 0.35 (95%CI 0.18-0.68), p = 0.002) . CONCLUSIONS: BITA revascularization did not impact early outcome in patients with CRF, but demonstrated a significant protective effect on long-term survival in the unmatched and matched cohorts.

Successful conservative management of left ventricular assist device candidates.

AIMS: Clinical trials comparing LVADs vs. conservative therapy were performed before the availability of novel medications or used suboptimal medical therapy. This study aimed to report that long-term stabilization of patients entering a left ventricular assist device (LVAD) programme is possible with the use of aggressive conservative therapy. This is important because the excellent clinical stabilization provided by LVADs comes at the expense of significant complications. METHODS AND RESULTS: This study was a single-centre prospective evaluation of consecutive patients with advanced heart failure (HF) fulfilling criteria for LVAD implantation based on clinical and echocardiographic characteristics, cardiopulmonary exercise test, and right heart catheterization results. Their initial therapy included inotropes, thiamine, beta-blockers, digoxin, spironolactone, hydralazine, and nitrates followed by the introduction of novel HF therapies. Coronary revascularization and cardiac resynchronization therapy were performed when indicated, and all patients were closely followed at our outpatient clinic. During the study period, 28 patients were considered suitable for LVAD implantation (mean age 63 ± 10.8 years, 92% men, 78% ischaemic, median HF duration 4 years). Clinical stabilization was achieved and maintained in 21 patients (median follow-up 20 months, range 9-38 months). Compared with baseline evaluation, cardiac index increased from 2.05 (1.73-2.28) to 2.88 (2.63-3.55) L/min/m2 , left ventricular end-diastolic diameter decreased from 65.5 (62.4-66) to 58.3 (53.8-62.5) mm, and maximal oxygen consumption increased from 10.1 (9.2-11.3) to 16.1 (15.3-19) mL/kg/min. Three patients died and only four ultimately required LVAD implantation. CONCLUSIONS: Notwithstanding the small size of our cohort, our results suggest that LVAD implantation could be safely deferred in the majority of LVAD candidates.

Applying Artificial Intelligence Privacy Technology in the Healthcare Domain.

Regulations set out strict restrictions on processing personal data. ML models must also adhere to these restrictions, as it may be possible to infer personal information from trained models. In this paper, we demonstrate the use of two novel AI Privacy tools in a real-world healthcare application.

Early and late outcomes of single versus bilateral internal thoracic artery revascularization for patients in critical condition.

OBJECTIVE: The optimal surgical approach for critically ill patients with complex coronary disease remains uncertain. We compared outcomes of bilateral internal thoracic artery (BITA) versus single ITA (SITA) revascularization in critical patients. METHODS: We evaluated 394 consecutive critical patients with multi-vessel disease who underwent CABG during 1996-2001. Outcomes measured were early mortality, strokes, myocardial-infarctions, sternal infections, revisions for bleeding, and late survival. The critical preoperative state was acknowledged concisely by one or more of the following: preoperative ventricular tachycardia/fibrillation, aborted sudden cardiac death, or the need for mechanical ventilation or for preoperative insertion of intra-aortic-balloon counter-pulsation. RESULTS: During the study period, 193 of our patients who underwent SITA and 201 who underwent BITA were in critical condition. The SITA group was older (mean 68.0 vs. 63.3 years, p = 0.001) and higher proportions were females (28.5% vs. 18.9% p = 0.025), after recent-MI (69.9% vs. 57.2% p = 0.009) and with left-main disease (38.3% vs. 49.3% p = .029); the median logistic EuroSCORE was higher (0.2898 vs. 0.1597, p<0.001). No statistically significant differences were observed between the SITA and BITA groups in 30-day mortality; and in rates of early CVA, MI and sternal infections (13.0% vs. 8.5%, p = 0.148; 4.1% vs. 6.0%, p = 0.49; 6.7% vs. 4.5%, p = 0.32 and 2.1% vs. 2.5%, p>0.99, respectively). Long-term survival (median follow-up of 15 years, interquartile-range: 13.57-15) was better in the BITA group (median 14.39 vs. 9.31± 0.9 years, p = 0.001). Propensity-score matching (132 matched pairs) also yielded similar early outcomes and improved long-term survival (median follow-up of 15 years, interquartile-range: 13.56-15) for the BITA group (median 12.49±1.71 vs. 7.63±0.99 years, p = 0.002). In multivariable analysis, BITA revascularization was found to be a predictor for improved survival (hazard-ratio of 0.419, 95%CI 0.23-0.76, p = 0.004). CONCLUSIONS: This study demonstrated long-term survival benefit for BITA revascularization in patients in a critical pre-operative state who presented for surgical revascularization.

Is the Use of BITA vs SITA Grafting Safe and Beneficial in Octogenarians?

BACKGROUND: Bilateral internal thoracic artery (BITA) grafting is questionable in octogenarians because of shorter life expectancy and increased risk of perioperative complications. The aim of this study was to examine the safety and effectiveness of performing BITA and single internal thoracic artery (SITA) grafts in patients older than 80 years of age. METHODS: This study compared outcomes in 201 consecutive octogenarians who underwent isolated BITA grafting with those of 280 consecutive octogenarians who underwent SITA and saphenous vein grafting during 1996 to 2011. Insulin-dependent diabetes, ejection fraction <30, and emergency operations were more common among patients who underwent SITA, and the prevalence of left main coronary artery disease was lower. Propensity score matching was used to control for these differences, thus generating well-matched groups of 190 patients each. RESULTS: There were no significant differences in early mortality between the unmatched groups: 3.2% in the BITA group and 8.6% in the SITA group (P = .12). Rates of sternal wound infection were also similar, 1.5% vs 1.7%, respectively. Differences were not observed in the occurrences of perioperative stroke (3.5% vs 2.5%; P = .999) and myocardial infarction (1.5% vs 3.6%; P = .166). The results were similar for the matched groups. Long-term survival between the unmatched groups and survival between the matched groups were not significantly different. CONCLUSIONS: This study shows equal long-term survival for BITA and SITA grafting in octogenarians. BITA is an acceptable alternative to SITA grafting in low-risk octogenarians and in the presence of a calcified aorta or poor-quality saphenous vein graft.

Is gender a risk factor for bilateral internal thoracic artery grafting? A twenty-year follow-up.

BACKGROUND: Although bilateral internal thoracic artery (BITA) grafting is associated with improved survival, many surgeons are reluctant to use this technique, especially in female patients, due to its greater complexity and potential increased risk of sternal infection. The aim of this study was to compare the outcomes of male and female patients who underwent BITA grafting. METHODS: We evaluated at the early outcome and late mortality, 551 female versus 2525 male patients who underwent isolated BITA grafting between January 1996 and December 2011. To adjust for differences in demographic and clinical characteristics, a multivariate risk analysis and propensity score matching were performed. Kaplan-Meier analysis was performed for the entire cohort and for the matched cohort. RESULTS: Female patients were older and were more likely than males to have congestive heart failure, unstable angina pectoris, and diabetes. Sternal infection was more frequent in females than males (3.3% vs. 1.8%; p = .04). Differences were not observed in operative mortality (2.9% vs. 1.9%; p = .15) and stroke incidence (3.4% vs. 2.6; p = .30). After multivariate risk analysis and propensity score matching, the female gender was not found to be a predictor of worse outcomes. There was no difference in median survival among female and male patients (14.3 and 14.2 years, respectively; p = .68). CONCLUSION: Our results support the routine use of BITA grafting in proper selected female patients who undergo myocardial revascularization.

Late Outcomes of In Situ Versus Composite Bilateral Internal Thoracic Artery Revascularization.

BACKGROUND: We compared 2 configurations for revascularization of the internal thoracic arteries to the anterior and lateral walls. In the "in situ" configuration, an in situ right internal thoracic artery supplies the left anterior descending territory, and an in situ left internal thoracic artery is grafted to the left circumflex territory. In the "composite" configuration, an in situ left internal thoracic artery is grafted to the left anterior descending artery and a free right internal thoracic artery is attached end-to-side to the left internal thoracic artery and supplies the lateral wall. METHODS: We compared outcomes of all the patients treated in our center by the described strategies during 1996 through 2011. RESULTS: Of 2951 patients, 1220 underwent composite grafting and 1731 underwent in situ grafting; the median follow-up was 15.1 years (interquartile range, 11.2-18.6 years). Early mortality (2.2% vs 2.0%, P = .787) and other early adverse outcomes did not differ significantly between the groups. Long-term (15-year) survival was marginally significant in favor of the in situ group (53.5% vs 49.5%, P = .05); this difference disappeared after 20 years. Configuration strategy was not a predictor for better 15-year survival in multivariable analysis (hazard ratio, 0.97; 95% confidence interval, 0.85-1.09; P = .568). An additional analysis compared matched groups of 995 patients each who underwent the 2 configuration strategies and found no differences in early outcome or late survival between the groups. CONCLUSIONS: This study demonstrated the safety and effectiveness of 2 strategies for bilateral internal thoracic artery revascularization to the left side, with comparable early outcomes and long-term survival.

Single versus bilateral internal thoracic artery grafting in patients with low ejection fraction.

Coronary artery bypass grafting (CABG) is the standard of care for the treatment of complex coronary artery disease. However, the optimal surgical treatment for patients with reduced left ventricular function with low ejection fraction (EF) is inconclusive. In our center, left-sided coronary grafting with bilateral internal thoracic artery (BITA) is generally the preferred method for surgical revascularization, also for patients with low EF. We compared early and long-term outcomes between BITA grafting and single internal thoracic artery (SITA) grafting in patients with low EF.We evaluated short- and long-term outcomes of all patients who underwent surgical revascularization in our center during 1996 to 2011, according to EF ≥30% and <30%. Univariate and multivariate analyses were performed. In addition, patients who underwent BITA and SITA grafting were matched using propensity score matching.In total, 5337 patients with multivessel disease underwent surgical revascularization during the study period. Of them, 394 had low EF. Among these, 188 underwent SITA revascularization and 206 BITA grafting. Those who underwent SITA were more likely to have comorbidities such as chronic obstructive pulmonary disease, diabetes, congestive heart failure, chronic renal failure, and a critical preoperative condition including preoperative intra-aortic balloon pump insertion.Statistically significant differences were not observed between the SITA and BITA groups in 30-day mortality (8.5% vs 6.8%, P = .55), sternal wound infection (2.7% vs 1.0%, P = .27), stroke (3.7% vs 6.3%, P = .24), and perioperative myocardial infarction (5.9% vs 2.9%, P = .15). Long-term survival (median follow up of 14 years, interquartile range, 11.2-18.9) was also similar between the groups. Propensity score matching (129 matched pairs) yielded similar early and long-term outcomes for the groups.This study did not demonstrate any clinical benefit for BITA compared with SITA revascularization in individuals with low EF.

Does bilateral versus single thoracic artery grafting provide survival benefit in female patients?

OBJECTIVES: Bilateral internal thoracic artery (BITA) grafting is associated with improved survival, but this technique is reluctantly used in women due to an increased risk of sternal wound infection. The aim of this study was to compare the long-term survival of women who underwent BITA grafting and single internal thoracic artery (SITA) grafting. METHODS: We performed a retrospective analysis of 556 consecutive female BITA patients and 685 female SITA patients. RESULTS: SITA patients were older and more likely to have comorbidities (diabetes mellitus, chronic lung disease, chronic renal failure, peripheral vascular disease and cerebral vascular disease). Operative mortality showed a trend towards a benefit for BITA (2.9% vs 5.0% for SITA, P = 0.06). The sternal wound infection rates were similar (3.4% vs 2.9%, P = 0.6); however, the occurrence of stroke was significantly lower in the SITA group (3.4% vs 1.2%, P = 0.007). The median survival of the BITA group was significantly better {13.8 years [95% confidence interval (CI) 12.8-14.9] vs 10.3 years [95% CI 9.6-11.1], P = 0.001}. After propensity score matching (491 pairs), the assignment to BITA was not associated with increased early mortality or complication rates, and the choice of BITA grafting was associated with better survival [14.5 years (95% CI 13.3-15.6) vs 11.8 years (95% CI 10.7-12.9)]. Only the choice of conduits was associated with increased late mortality (multivariable analysis, hazard ratio 1.28, 95% CI 1.024-1.591; P = 0.03). CONCLUSIONS: The low early mortality and complication rate, and the long-term survival benefit of BITA compared to SITA grafting, support the use of BITA grafting in women.

Axial to Centrifugal Continuous Flow LVAD Pump Exchange Using Minimally Invasive Technique.

Driveline or device infection may complicate left ventricular assist device implants, and only curative option may be pump exchange. Replacement with similar device may be liable to reinfection, because pump configuration is such that the new device and driveline may partly lie within the pocket of the previous pump. One approach to overcome this is using a different pump design such that the new pump would lie in a different location from the old pump. We describe treatment of severe HeartMate II (Abbott, [St Jude Thoratec Corp], Pleasanton, CA USA) left ventricular assist device infection by minimally invasive exchange to an intrapericardial HVAD (HeartWare International, Inc, Framingham, MA USA) left ventricular assist device.

A Novel Computational Tool for Mining Real-Life Data: Application in the Metastatic Colorectal Cancer Care Setting.

BACKGROUND: Randomized clinical trials constitute the gold-standard for evaluating new anti-cancer therapies; however, real-life data are key in complementing clinically useful information. We developed a computational tool for real-life data analysis and applied it to the metastatic colorectal cancer (mCRC) setting. This tool addressed the impact of oncology/non-oncology parameters on treatment patterns and clinical outcomes. METHODS: The developed tool enables extraction of any computerized information including comorbidities and use of drugs (oncological/non-oncological) per individual HMO member. The study in which we evaluated this tool was a retrospective cohort study that included Maccabi Healthcare Services members with mCRC receiving bevacizumab with fluoropyrimidines (FP), FP plus oxaliplatin (FP-O), or FP plus irinotecan (FP-I) in the first-line between 9/2006 and 12/2013. RESULTS: The analysis included 753 patients of whom 15.4% underwent subsequent metastasectomy (the Surgery group). For the entire cohort, median overall survival (OS) was 20.5 months; in the Surgery group, median duration of bevacizumab-containing therapy (DOT) pre-surgery was 6.1 months; median OS was not reached. In the Non-surgery group, median OS and DOT were 18.7 and 11.4 months, respectively; no significant OS differences were noted between FP-O and FP-I, whereas FP use was associated with shorter OS (12.3 month; p <0.002; notably, these patients were older). Patients who received both FP-O- and FP-I-based regimens achieved numerically longer OS vs. those who received only one of these regimens (22.1 [19.9-24.0] vs. 18.9 [15.5-21.9] months). Among patients assessed for wild-type KRAS and treated with subsequent anti-EGFR agent, OS was 25.4 months and 18.7 months for 124 treated vs. 37 non-treated patients (non-significant). Cox analysis (controlling for age and gender) identified several non-oncology parameters associated with poorer clinical outcomes including concurrent use of diuretics and proton-pump inhibitors. CONCLUSIONS: Our tool provided insights that confirmed/complemented information gained from randomized-clinical trials. Prospective tool implementation is warranted.

Understanding Deviations from Clinical Practice Guidelines in Adult Soft Tissue Sarcoma.

In recent years we have witnessed the increasing adoption of clinical practice guidelines (CPGs) as decision support tools that guide medical treatment. As CPGs gain popularity, it has become evident that physicians frequently deviate from CPG recommendations, both erroneously and due to sound medical rationale. In this study we developed a methodology to computationally identify these deviation cases and understand their movitation. This was achieved using an integrated approach consisting of natural language processing, data modeling, and comparison methods to characterize deviations from CPG recommendations for 1431 adult soft tissue sarcoma patients. The results show that 48.9% of patient treatment programs deviate from CPG recommendations, with the largest deviation type being overtreatment, followed by differences in drug treatments. Interestingly, we identified over a dozen potential reasons for these deviations, with those directly related to the patients' cancer status being most abundant. These findings can be used to modify CPGs, increase adherence to CPG recommendations, reduce treatment cost, and potentially impact sarcoma care. Our approach can be applied to additional diseases that are subject to high deviation levels from CPGs.

TLR4 Expression Is Associated with Left Ventricular Dysfunction in Patients Undergoing Coronary Artery Bypass Surgery.

INTRODUCTION: Toll-like receptor 4 (TLR4) is an innate immune receptor expressed in immune cells and the heart. Activation of the immune system following myocardial ischemia causes the release of proinflammatory mediators that may negatively influence heart function. AIM: The aim of this study is to determine whether TLR4 is activated in peripheral monocytes and heart tissue taken from patients with varying degrees of myocardial dysfunction caused by coronary artery diseases and scheduled for coronary artery bypass graft (CABG) surgery before 12 months following operation. METHODS AND RESULTS: Patients (n = 44) undergoing CABG surgery having left ventricular ejection fraction ≤ 45% ('reduced EF', n = 20) were compared to patients with preserved EF >45% ('preserved EF' group, n = 24). 'Reduced EF' patients exhibited increased TLR4 expression in monocytes (2.78±0.49 vs. 1.76±0.07 rMFI, p = 0.03). Plasma levels of C-reactive protein, microRNA miR-320a, brain natriuretic peptide (pro BNP) and NADPH oxidase (NOX4) were also significantly different between the 'preserved EF' and 'reduced EF'groups. Elevated TLR4 gene expression levels in the right auricle correlated with those of EF (p<0.008), NOX4 (p<0.008) and miR320, (p<0.04). In contrast, no differences were observed in peripheral monocyte TLR2 expression. After CABG surgery, monocyte TLR4 expression decreased in all patients, reaching statistical significance in the 'reduced EF' group. CONCLUSION: TLR4 is activated in peripheral monocytes and heart tissue obtained from patients with ischemic heart disease and reduced left ventricular function. Coronary revascularization decreases TLR4 expression. We therefore propose that TLR4 plays a pathogenic role and may serve as an additional marker of ischemic myocardial dysfunction.

A model-driven approach to clinical practice guidelines representation and evaluation using standards.

Clinical Practice Guidelines (CPGs) contain a set of schematic plans for the treatment and management of patients who have a particular clinical condition. CPGs are increasingly being used to support physician decision making. Many groups develop tools for the representation of CPGs. These differ in their approaches to addressing particular modeling challenges. Despite this strong effort, physicians still primarily rely on free-text narrative descriptions. Thus, a core challenge is to develop a formal representation of CPGs that physicians can easily read and verify, yet a machine can process, analyze and apply directly to a patient's EHR data. Our paper proposes a solution to this fundamental problem by describing an approach to CPG formalization using the Natural Rule Language (NRL), coupled with transformation to Object Constraint Language (OCL) constraints that are applied on a patient's clinical data record, in our case an HL7 Continuity of Care Document (CCD). We illustrate our approach on a simple guideline directive for Essential Hypertension.

Analyzing the "CareGap": assessing gaps in adherence to clinical guidelines in adult soft tissue sarcoma.

Clinical decision support systems (CDSSs) are gaining popularity as tools that assist physicians in optimizing medical care. These systems typically comply with evidence-based medicine and are designed with input from domain experts. Nonetheless, deviations from CDSS recommendations are abundant across a broad spectrum of disorders, raising the question as to why this phenomenon exists. Here, we analyze this gap in adherence to a clinical guidelines-based CDSS by examining the physician treatment decisions for 1329 adult soft tissue sarcoma patients in northern Italy using patient-specific parameters. Dubbing this analysis "CareGap", we find that deviations correlate strongly with certain disease features such as local versus metastatic clinical presentation. We also notice that deviations from the guideline-based CDSS suggestions occur more frequently for patients with shorter survival time. Such observations can direct physicians' attention to distinct patient cohorts that are prone to higher deviation levels from clinical practice guidelines. This illustrates the value of CareGap analysis in assessing quality of care for subsets of patients within a larger pathology.

Bringing research to the point of care: Hypergenes project study.

With advance of health information IT systems and increasing volumes of disparate biomedical information repositories, harvesting them for research purposes is becoming more difficult. This is partly due to the proprietary nature of the current systems, but also due to diverse requirements of different research paradigms. On the flip side, ever larger amounts of clinical and genomic data are currently accumulated in research projects. Tapping into these research silos would not only contribute to further research, but could help convey timely information to clinicians at the point of care. This paper presents RIMon - a portal-based infrastructure for information-intensive research cycle as used in the Hypergenes project, which aims at building a method to dissect complex genetic traits using essential hypertension as a disease model. RIMon allows users to: (a) collect data from points of care, (b) query and retrieve collected data for analysis, (c) query accumulated information and knowledge to construct disease models based on analysis results, and (d) to eventually make the research results readily available to the clinicians at the point of care. This translational cycle is demonstrated in the Hypergenes project along with a potential usage scenario.

A standard based approach for biomedical knowledge representation.

The new generation of health information standards, where the syntax and semantics of the content is explicitly formalized, allows for interoperability in healthcare scenarios and analysis in clinical research settings. Studies involving clinical and genomic data include accumulating knowledge as relationships between genotypic and phenotypic information as well as associations within the genomic and clinical worlds. Some involve analysis results targeted at a specific disease; others are of a predictive nature specific to a patient and may be used by decision support applications. Representing knowledge is as important as representing data since data is more useful when coupled with relevant knowledge. Any further analysis and cross-research collaboration would benefit from persisting knowledge and data in a unified way. This paper describes a methodology used in Hypergenes, an EC FP7 project targeting Essential Hypertension, which captures data and knowledge using standards such as HL7 CDA and Clinical Genomics, aligned with the CEN EHR 13606 specification. We demonstrate the benefits of such an approach for clinical research as well as in healthcare oriented scenarios.

Large scale healthcare data integration and analysis using the semantic web.

Healthcare data interoperability can only be achieved when the semantics of the content is well defined and consistently implemented across heterogeneous data sources. Achieving these objectives of interoperability requires the collaboration of experts from several domains. This paper describes tooling that integrates Semantic Web technologies with common tools to facilitate cross-domain collaborative development for the purposes of data interoperability. Our approach is divided into stages of data harmonization and representation, model transformation, and instance generation. We applied our approach on Hypergenes, an EU funded project, where we use our method to the Essential Hypertension disease model using a CDA template. Our domain expert partners include clinical providers, clinical domain researchers, healthcare information technology experts, and a variety of clinical data consumers. We show that bringing Semantic Web technologies into the healthcare interoperability toolkit increases opportunities for beneficial collaboration thus improving patient care and clinical research outcomes.

A model-driven approach for biomedical data integration.

A core challenge in biomedical data integration is to enable semantic interoperability between its various stakeholders as well as other interested parties. Promoting the adoption of worldwide accepted information standards along with common controlled terminologies is the right path to achieve this. Our paper describes a solution to this fundamental problem by proposing an approach to semantic data integration based on information models serving as a common language to represent health data coupled with technology that is able to represent the data semantics. We used the HL7 v3 Reference Information Model (RIM) [1] to derive a specific data model for the integrated data, the Web Ontology Language (OWL) [2] to build an ontology that harmonizes the metadata from the disparate data sources, the Unified Modeling Language (UML) [3] to model the data representation, and the Object Constraint Language (OCL) [4] to specify UML model constraints. To illustrate the approach, we use the Essential Hypertension Summary CDA document and related models from Hypergenes, a European Commission funded project [5] exploring the Essential Hypertension disease model.

The effect of cardiac angiography timing, contrast media dose, and preoperative renal function on acute renal failure after coronary artery bypass grafting.

OBJECTIVE: Our objective was to assess the effect of the timing of cardiac angiography, contrast media dose, and preoperative renal function on the prevalence of acute renal failure after cardiac surgery. METHODS: Data on 395 consecutive patients who underwent coronary artery bypass grafting were prospectively collected. Creatinine clearance was estimated by the Cockcroft-Gault equation. Patients were divided into 3 groups according to the time between cardiac angiography and surgery (group A, < or = 1 day; group B, > 1 day and < or = 5 days; group C, > 5 days). Patients who underwent a salvage operation or were receiving dialysis before surgery were excluded. Acute renal failure was defined as 25% decrease from baseline of estimated creatinine clearance and estimated creatinine clearance of 60 mL/min or less on postoperative day 3. Owing to differences in preoperative characteristics between groups, propensity score analysis was used to adjust those differences. RESULTS: Acute renal failure developed in 13.6% of patients. Hospital mortality was 3.3% and was higher in patients in whom acute renal failure developed (22%) versus those in whom it did not (0.3%; P < .001). Multivariable analysis identified preoperative estimated creatinine clearance of 60 mL/min or less (odds ratio [OR], 7.1), operation within 24 hours of catheterization (OR = 3.7), use of more than 1.4 mL/kg of contrast media (OR = 3.4), lower hemoglobin level (OR = 1.3), older age (OR = 1.1), and lower weight (OR = 0.95) as independent predictors of postoperative acute renal failure. Analysis of interaction between contrast dose and time of surgery revealed that high contrast dose (>1.4 mL/kg) predicted acute renal failure if surgery was performed up to 5 days after angiography. CONCLUSIONS: Whenever possible, coronary bypass grafting should be delayed for at least 5 days in patients who received a high contrast dose, especially if they also have preoperative reduced renal function.