1,721,008 research outputs found
Accuracy, calibration and clinical performance of the EuroSCORE: can we reduce the number of variables?
No full textBACKGROUND:
The European system for cardiac operative risk evaluation (EuroSCORE) is currently used in many institutions and is considered a reference tool in many countries. We hypothesised that too many variables were included in the EuroSCORE using limited patient series. We tested different models using a limited number of variables.
METHODS:
A total of 11150 adult patients undergoing cardiac operations at our institution (2001-2007) were retrospectively analysed. The 17 risk factors composing the EuroSCORE were separately analysed and ranked for accuracy of prediction of hospital mortality. Seventeen models were created by progressively including one factor at a time. The models were compared for accuracy with a receiver operating characteristics (ROC) analysis and area under the curve (AUC) evaluation. Calibration was tested with Hosmer-Lemeshow statistics. Clinical performance was assessed by comparing the predicted with the observed mortality rates.
RESULTS:
The best accuracy (AUC 0.76) was obtained using a model including only age, left ventricular ejection fraction, serum creatinine, emergency operation and non-isolated coronary operation. The EuroSCORE AUC (0.75) was not significantly different. Calibration and clinical performance were better in the five-factor model than in the EuroSCORE. Only in high-risk patients were 12 factors needed to achieve a good performance.
CONCLUSIONS:
Including many factors in multivariable logistic models increases the risk for overfitting, multicollinearity and human error. A five-factor model offers the same level of accuracy but demonstrated better calibration and clinical performance. Models with a limited number of factors may work better than complex models when applied to a limited number of patients
Major bleeding, transfusions, and anemia: the deadly triad of cardiac surgery.
No full textPostoperative bleeding is common after cardiac surgery. Major bleeding (MB) is a determinant of red blood cell (RBC) transfusion, especially in patients with preoperative anemia. Preoperative anemia and RBC transfusions are recognized risk factors for operative mortality. The present study investigates the role of MB as an independent determinant of operative mortality in cardiac surger
Accuracy, calibration and clinical performance of the new EuroSCORE II risk stratification system.
No full textOBJECTIVES:
The European System for Cardiac Operative Risk Evaluation (EuroSCORE) has been used for many years since its introduction in 1999. Recently, a new EuroSCORE (EuroSCORE II) has been developed to update the previous version. The EuroSCORE II includes some different predictors and/or introduces a new classification of the already existing predictors. This study presents a validation series for the EuroSCORE II compared with the previous additive and the logistic EuroSCORE and with the Age, Creatinine and Ejection Fraction (ACEF) score.
METHODS:
A total of 1090 consecutive adult patients operated on at our institution from September 2010 to October 2011 were admitted to this retrospective study. All the patients received a risk stratification based on the EuroSCORE II and the other scores considered. Accuracy, calibration and clinical performance of the various risk models were assessed.
RESULTS:
The accuracy of the EuroSCORE II was good (c-statistic 0.81) but not significantly higher than the other scores (range 0.78-0.8). Calibration at the Hosmer-Lemeshow statistic was good for all the scores; the difference between observed (3.75%) and predicted mortality in the overall population was not significant for the EuroSCORE II (3.1%) and the ACEF score (3.4%), whereas the additive EuroSCORE (5.8%) and the logistic EuroSCORE (7.3%) significantly overestimated the risk. In patients at low, mild moderate and high mortality risk, the EuroSCORE II provided a risk prediction not significantly different from the observed mortality rate, whereas in very high-risk patients (observed mortality rate 11%), it significantly underestimated (6.5%) the mortality risk. The accuracy of the EuroSCORE II was acceptable in isolated coronary surgery, and good or excellent in the other operations.
CONCLUSIONS:
The EuroSCORE II represents a useful update of the previous EuroSCORE version, with a much better clinical performance and the same good level of accuracy. It is possible that for the risk stratification of very high-risk patients, other factors (rare but associated with a mortality rate >50%) should be included in the future models
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Coronary artery fistulas: clinical consequences and methods of closure. A literature review
No full textCoronary fistulas are uncommon anomalies of congenital and rarely iatrogenic etiology. Their clinical significance is mainly dependent on the severity of the left-to-right shunt they are responsible for. Symptoms, high-flow shunting and the occurrence of complications, only partially related to the magnitude of the shunt, are the main indications for their closure, especially in the adult population. Pediatric patients, even asymptomatic but presenting with electrocardiographic or chest X-ray abnormalities, should be treated in order to avoid the long-term complications related to the presence of the fistula. Treatment of adult asymptomatic patients with non-significant shunting is still a matter of debate. Surgery and direct epicardial or endocardial ligation were traditionally viewed as the main therapeutic method for the closure of coronary fistulas. Progress in the techniques of endoluminal intervention has led to fistula embolization using different devices including coils, balloons and chemicals. The success rate is good and the procedure-related morbidity acceptable
Predicting transfusions in cardiac surgery: the easier, the better: the Transfusion Risk and Clinical Knowledge score
No full textBACKGROUND AND OBJECTIVES: Allogeneic blood products transfusions are associated with an increased morbidity and mortality risk in cardiac surgery. At present, a few transfusion risk scores have been proposed for cardiac surgery patients. The present study is aimed to develop and validate a risk score based on adequate statistical analyses joint with a clinical selection of a limited (five) number of preoperative predictors.
MATERIALS AND METHODS: The development series was composed of 8989 consecutive adult patients undergone cardiac surgery. Independent predictors of allogeneic blood transfusions were identified. Subsequently, five predictors were extracted as the most clinically relevant based on the judgement of 30 clinicians dealing with transfusions in cardiac surgery. A predictive score was developed and externally validated on a series of 2371 patients operated in another institution. The score was compared to the other existing scores.
RESULTS: The following predictors constituted the Transfusion Risk and Clinical Knowledge score: age > 67 years; weight < 60 kg for females and < 85 kg for males preoperative haematocrit; gender--female; and complex surgery. At the external validation, this score demonstrated an acceptable predictive power (area under the curve 0.71) and a good calibration at the Hosmer-Lemeshow test. When compared to the other three existing risk scores, the Transfusion Risk and Clinical Knowledge score had comparable or better predictive power and calibration.
CONCLUSION: A simple risk model based on five predictors only has a similar or better accuracy and calibration in predicting the transfusion rate in cardiac surgery than more complex models
Association of Gender and Lowest Hematocrit on Cardiopulmonary Bypass With Acute Kidney Injury and Operative Mortality in Patients Undergoing Cardiac Surgery
No full textPrognostic value of left atrial strain quantification from 2D ultrasound imaging in post-ischemic heart failure patients: evidence from the REMODEL-HF study
Full text linkBackground. Left atrial (LA) function can be effectively assessed by measuring longitudinal LA strain (LAS) via two-dimensional speckle tracking echocardiography (2DSTE). Here, we test 2DSTE-based LAS as marker of different left ventricle (LV) remodeling patterns and as prognostic index in ischemic heart failure (HF) candidates to surgical ventricular reconstruction. Methods. We retrospectively considered ischemic HF patients with anterior (group A, n=130) or posterior (group P, n=48) LV remodeling. Based on 2D ultrasound, LV and LA morpho-functional parameters were quantified including reservoir (LASRes), conduit (LASCond) and booster (LASBoost) LAS. We tested their capability to discriminate between groups A and P, and their group-specific prognostic significance for the composite end-point of death or HF re-hospitalization at follow-up (mean follow-up time=40 months, range 3-101 months). Results. Group A and group P displayed similar end-diastolic (p=0.89) and end-systolic (p=0.33) LV volume index, and LA volume index LAVi (p=0.44) corrected for the degree of mitral regurgitation. As compared to group P, group A revealed a significant reduction in LASBoost (9.2±0.4% vs. 11.1±0.7%, p=0.04) and a non-significant reduction in LASRes (16.9±0.7% vs. 19.3±1.1%, p=0.06). Kaplan-Meier curves showed that the median LASRes and LASBoost values effectively stratified patients based on their prognosis in the overall study population (Log-rank p=0.002 and Log_rank p<0.0001) and in group A, where the association was stronger for LASBoost (Log-rank p<0.001) than for LASRes (Log-rank p=0.013). Conclusions. 2DSTE-based LAS assessment is affordable, repeatable and non-invasive, and could add clinically-relevant mechanistic insight and prognostic value in the stratification of ischemic HF patients
Impact of preoperative anemia on outcome in adult cardiac surgery: a propensity-matched analysis.
No full textPreoperative anemia is not considered an operative mortality risk factor by the majority of the risk stratification tools used in cardiac surgery. However, retrospective studies have found associations between preoperative anemia and morbidity and mortality in cardiac operations. The present study compares the postoperative outcome of a group of moderate-to-severe anemic patients with a propensity-matched group of nonanemic patients undergoing cardiac operations.
METHODS:
This is a retrospective study based on 17,056 consecutive patients included in our Institutional Database. A total of 13,843 adult patients with preoperative hematocrit value available were selected for this study; 401 patients had a severe anemia (hematocrit<30%). From the remaining patients, a control group of 401 non-severely anemic patients was selected with a propensity-based matching. Postoperative morbidity and mortality were compared between the 2 groups.
RESULTS:
The 2 groups were comparable for preoperative comorbidities and operative details. Anemic patients had a significantly (p=0.045) higher rate of stroke (1% vs 0%), major morbidity (27.4% vs 17.5%, p=0.001), and a significantly higher (0.014) operative mortality rate (12.7% vs 7.5%). An additional analysis, inclusive of patients with moderate preoperative anemia, confirmed these results.
CONCLUSIONS:
Moderate-to-severe preoperative anemia is a risk factor for major morbidity and operative mortality in adult cardiac operations. This finding is confirmative of the role of preoperative anemia in determining adverse events in major noncardiac operations. The exclusion of preoperative anemia from the existing risk scores is probably a statistical consequence of the associated comorbid conditions that confound the specific role of anemia as a risk factor
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