Interacting innovation processes.

In this work, we introduce a general model for a collection of innovation processes in order to model and analyze the interaction among them. We provide theoretical results, analytically proven, and we show how the proposed model fits the behaviors observed in some real data sets (from Reddit and Gutenberg). It is worth mentioning that the given applications are only examples of the potentialities of the proposed model and related results: due to its abstractness and generality, it can be applied to many interacting innovation processes.

A Semi-Supervised Reduced-Space Method for Hyperspectral Imaging Segmentation.

The development of the hyperspectral remote sensor technology allows the acquisition of images with a very detailed spectral information for each pixel. Because of this, hyperspectral images (HSI) potentially possess larger capabilities in solving many scientific and practical problems in agriculture, biomedical, ecological, geological, hydrological studies. However, their analysis requires developing specialized and fast algorithms for data processing, due the high dimensionality of the data. In this work, we propose a new semi-supervised method for multilabel segmentation of HSI that combines a suitable linear discriminant analysis, a similarity index to compare different spectra, and a random walk based model with a direct label assignment. The user-marked regions are used for the projection of the original high-dimensional feature space to a lower dimensional space, such that the class separation is maximized. This allows to retain in an automatic way the most informative features, lightening the successive computational burden. The part of the random walk is related to a combinatorial Dirichlet problem involving a weighted graph, where the nodes are the projected pixel of the original HSI, and the positive weights depend on the distances between these nodes. We then assign to each pixel of the original image a probability quantifying the likelihood that the pixel (node) belongs to some subregion. The computation of the spectral distance involves both the coordinates in a features space of a pixel and of its neighbors. The final segmentation process is therefore reduced to a suitable optimization problem coupling the probabilities from the random walker computation, and the similarity with respect the initially labeled pixels. We discuss the properties of the new method with experimental results carried on benchmark images.

A Semiautomatic Multi-Label Color Image Segmentation Coupling Dirichlet Problem and Colour Distances.

Image segmentation is an essential but critical component in low level vision, image analysis, pattern recognition, and now in robotic systems. In addition, it is one of the most challenging tasks in image processing and determines the quality of the final results of the image analysis. Colour based segmentation could hence offer more significant extraction of information as compared to intensity or texture based segmentation. In this work, we propose a new local or global method for multi-label segmentation that combines a random walk based model with a direct label assignment computed using a suitable colour distance. Our approach is a semi-automatic image segmentation technique, since it requires user interaction for the initialisation of the segmentation process. The random walk part involves a combinatorial Dirichlet problem for a weighted graph, where the nodes are the pixel of the image, and the positive weights are related to the distances between pixels: in this work we propose a novel colour distance for computing such weights. In the random walker model we assign to each pixel of the image a probability quantifying the likelihood that the node belongs to some subregion. The computation of the colour distance is pursued by employing the coordinates in a colour space (e.g., RGB, XYZ, YCbCr) of a pixel and of the ones in its neighbourhood (e.g., in a 8-neighbourhood). The segmentation process is, therefore, reduced to an optimisation problem coupling the probabilities from the random walker approach, and the similarity with respect the labelled pixels. A further investigation involves an adaptive preprocess strategy using a regression tree for learning suitable weights to be used in the computation of the colour distance. We discuss the properties of the new method also by comparing with standard random walk and k-means approaches. The experimental results carried on the White Blood Cell (WBC) dataset and GrabCut datasets show the remarkable performance of the proposed method in comparison with state-of-the-art methods, such as normalised random walk and normalised lazy random walk, with respect to segmentation quality and computational time. Moreover, it reveals to be very robust with respect to the presence of noise and to the choice of the colourspace.

Twitter as an innovation process with damping effect.

In the existing literature about innovation processes, the proposed models often satisfy the Heaps' law, regarding the rate at which novelties appear, and the Zipf's law, that states a power law behavior for the frequency distribution of the elements. However, there are empirical cases far from showing a pure power law behavior and such a deviation is mostly present for elements with high frequencies. We explain this phenomenon by means of a suitable "damping" effect in the probability of a repetition of an old element. We introduce an extremely general model, whose key element is the update function, that can be suitably chosen in order to reproduce the behaviour exhibited by the empirical data. In particular, we explicit the update function for some Twitter data sets and show great performances with respect to Heaps' law and, above all, with respect to the fitting of the frequency-rank plots for low and high frequencies. Moreover, we also give other examples of update functions, that are able to reproduce the behaviors empirically observed in other contexts.

DDASSQ: An open-source, multiple peptide sequencing strategy for label free quantification based on an OpenMS pipeline in the KNIME analytics platform.

In this study we investigated the performance of a computational pipeline for protein identification and label free quantification (LFQ) of LC-MS/MS data sets from experimental animal tissue samples, as well as the impact of its specific peptide search combinatorial approach. The full pipeline workflow was composed of peptide search engine adapters based on different identification algorithms, in the frame of the open-source OpenMS software running within the KNIME analytics platform. Two different in silico tryptic digestion, database-search assisted approaches (X!Tandem and MS-GF+), de novo peptide sequencing based on Novor and consensus library search (SpectraST), were tested for the processing of LC-MS/MS raw data files obtained from proteomic LC-MS experiments done on proteolytic extracts from mouse ex vivo liver samples. The results from proteomic LFQ were compared to those based on the application of the two software tools MaxQuant and Proteome Discoverer for protein inference and label-free data analysis in shotgun proteomics. Data are available via ProteomeXchange with identifier PXD025097.

A model for the Twitter sentiment curve.

Twitter is among the most used online platforms for the political communications, due to the concision of its messages (which is particularly suitable for political slogans) and the quick diffusion of messages. Especially when the argument stimulate the emotionality of users, the content on Twitter is shared with extreme speed and thus studying the tweet sentiment if of utmost importance to predict the evolution of the discussions and the register of the relative narratives. In this article, we present a model able to reproduce the dynamics of the sentiments of tweets related to specific topics and periods and to provide a prediction of the sentiment of the future posts based on the observed past. The model is a recent variant of the Pólya urn, introduced and studied in Aletti and Crimaldi (2019, 2020), which is characterized by a "local" reinforcement, i.e. a reinforcement mechanism mainly based on the most recent observations, and by a random persistent fluctuation of the predictive mean. In particular, this latter feature is capable of capturing the trend fluctuations in the sentiment curve. While the proposed model is extremely general and may be also employed in other contexts, it has been tested on several Twitter data sets and demonstrated greater performances compared to the standard Pólya urn model. Moreover, the different performances on different data sets highlight different emotional sensitivities respect to a public event.

Taylor's Law in Innovation Processes.

Taylor's law quantifies the scaling properties of the fluctuations of the number of innovations occurring in open systems. Urn-based modeling schemes have already proven to be effective in modeling this complex behaviour. Here, we present analytical estimations of Taylor's law exponents in such models, by leveraging on their representation in terms of triangular urn models. We also highlight the correspondence of these models with Poisson-Dirichlet processes and demonstrate how a non-trivial Taylor's law exponent is a kind of universal feature in systems related to human activities. We base this result on the analysis of four collections of data generated by human activity: (i) written language (from a Gutenberg corpus); (ii) an online music website (Last.fm); (iii) Twitter hashtags; (iv) an online collaborative tagging system (Del.icio.us). While Taylor's law observed in the last two datasets agrees with the plain model predictions, we need to introduce a generalization to fully characterize the behaviour of the first two datasets, where temporal correlations are possibly more relevant. We suggest that Taylor's law is a fundamental complement to Zipf's and Heaps' laws in unveiling the complex dynamical processes underlying the evolution of systems featuring innovation.

Validation of a self-efficacy survey for Italian midwifery students with regard to breastfeeding support.

BACKGROUND: The training of midwives is critical in order to acquire the professional skills necessary in the support of breastfeeding. The use of tools that demonstrate student competency in the field of midwifery is fundamental. OBJECTIVES: The aim for this study was to translate and apply a questionnaire to an Italian cohort of students - determining their self-efficacy and establishing the validity of the tool collectively. DESIGN: This study was a descriptive cross-sectional study. SETTING: The study was conducted at a large university in northern Italy. PARTICIPANTS: Seventy-six female students from the Midwifery Degree Course. METHODS: The questionnaire translated into Italian was administered to students participating in a Midwifery Degree Course. Rasch analysis was applied using ConQuest software, version 4. RESULTS: Seventy-six questionnaires were collected. Fifty-six questionnaires have modal value 3 of the Likert response scale (It's easy for me to do it), 17 have a mode of 4 (It's very easy for me to do it), 3 of 2 (It's difficult for me to do it) and no questionnaire of 1 (It's very difficult for me to do it). A questionnaire identified the perception of self-efficacy of midwifery students in assisting breastfeeding mothers. CONCLUSION: The results of this research demonstrate that students of midwifery consider themselves competent when assisting breast feeding mothers.

Are delusional contents replayed during dreams?

The relationship between dream content and waking life experiences remains difficult to decipher. However, some neurobiological findings suggest that dreaming can, at least in part, be considered epiphenomenal to ongoing memory consolidation processes in sleep. Both abnormalities in sleep architecture and impairment in memory consolidation mechanisms are thought to be involved in the development of psychosis. The objective of this study was to assess the continuity between delusional contents and dreams in acutely psychotic patients. Ten patients with a single fixed and recurring delusional content were asked to report their dreams during an acute psychotic break. Sixteen judges with four different levels of acquaintance to the specific content of the patients' delusions were asked to group the dreams, expecting that fragments of the delusional thought would guide the task. A mathematical index (f,t) was developed in order to compare correct groupings between the four groups of judges. Most judges grouped the dreams slightly above chance level and no relevant differences could be found between the four groups [F(3,12)=1.297; p=n.s.]. Scoring of dreams for specific delusional themes suggested a continuity in terms of dream and waking mentation for two contents (Grandiosity and Religion). These findings seem to suggest that at least some delusional contents recur within patients' dreams. Future studies will need to determine whether such continuity reflects ongoing consolidation processes that are relevant to current theories of delusion formation and stabilization.

Inhalation versus endovenous sedation in subarachnoid hemorrhage patients: effects on regional cerebral blood flow.

OBJECTIVE: Isoflurane is a volatile anesthetic that has a vasodilating effect on cerebral vessels producing a cerebral blood flow increase. Furthermore, it has been shown in animal studies that isoflurane, when used as a preconditioning agent, has neuroprotective properties, inducing tolerance to ischemia. However, it is not routinely used in neurointensive care because of the potential increase in intracranial pressure caused by the rise in cerebral blood flow. Nevertheless, subarachnoid hemorrhage patients who are at risk for vasospasm may benefit from an increase in cerebral blood flow. We measured regional cerebral blood flow during intravenous sedation with propofol and during sedation with isoflurane in patients with severe subarachnoid hemorrhage not having intracranial hypertension. DESIGN: The study is a crossover, open clinical trial (NCT00830843). SETTING: Neurointensive care unit of an academic hospital. PATIENTS: Thirteen patients with severe subarachnoid hemorrhage, (median Fisher scale 4), monitored on clinical indication with intracranial pressure device and a thermal diffusion probe for the assessment of regional cerebral blood flow. An intracranial pressure>18 mm Hg was an exclusion criterion. INTERVENTIONS: Cerebral and hemodynamic variables were assessed at three steps. Step 1: sedation with propofol 3-4 mg/kg/hr; step 2: after 1 hr of propofol discontinuation and isoflurane 0.8%; step 3: after 1 hr of propofol at the same previous infusion rate. Cerebral perfusion pressure and arterial PCO2 were maintained constant. Mean cerebral artery flow velocity and jugular vein oxygen saturation were measured at the end of each step. MEASUREMENTS AND MAIN RESULTS: Regional cerebral blood flow increased significantly during step 2 (39.3±29 mL/100 hg/min) compared to step 1 (20.8±10.7) and step 3 (24.7±8). There was no difference in regional cerebral blood flow comparing step 1 vs. step 3. No significant difference in intracranial pressure, mean cerebral artery transcranial Doppler velocity, PaCO2, cerebral perfusion pressure between the different steps. CONCLUSIONS: Isoflurane increases regional cerebral blood flow in comparison to propofol. Intracranial pressure did not change significantly in the population not affected by intracranial hypertension.

Identification of patient groups at highest risk from traditional approach to ovarian cancer treatment.

OBJECTIVE: Define subgroups of patients at highest risk for major morbidity and mortality after a traditional approach of maximal surgical efforts followed by chemotherapy for advanced ovarian cancer (AOC). METHODS: Preoperative health, intra-operative findings and outcomes were assessed in consecutive patients with primary AOC from 4 centers. Initial tumor dissemination was stratified into 3 groups based on volume of disease. Surgery was categorized using a previously described surgical complexity score (SCS). Statistical analysis was directed toward validating a multivariable risk-adjusted model. RESULTS: 576 patients with stage IIIC (N=447, 77.6%) or IV AOC (N=129, 22.4%) were analyzed. Age (HR (per year): 1.02; 95%CI: 1.01-1.03), high tumor dissemination (HTD) (HR: 1.73; 95%CI: 1.19-2.56), residual disease (RD) >1 cm (HR: 2.46; 95%CI: 1.74-3.53), and stage IV (HR: 1.93; 95% CI: 1.51-2.45), independently correlated with OS. We identified a small subgroup of patients who comprised a high-risk group (N=38, 6.6%) characterized by all of the following characteristics: high initial tumor dissemination (HTD) or stage IV plus poor performance or nutritional status plus age ≥ 75. In this group, high SCS to achieve low RD was associated with morbidity of 63.6% and limited survival benefit. CONCLUSIONS: Optimal management of AOC requires accurate, risk-adjusted predictors of outcomes allowing a tailored approach starting with primary therapy. Complex surgical procedures to render low RD improve survival, and in the majority of cases, the benefits of such surgery appear to outweigh the morbidity. However careful analysis identifies a subgroup of patients in whom an alternative approach may be the better strategy.

A new frontier for quality of care in gynecologic oncology surgery: multi-institutional assessment of short-term outcomes for ovarian cancer using a risk-adjusted model.

OBJECTIVE: To test the feasibility and utility of a risk-adjusted, multicenter outcomes model for ovarian cancer surgery as a tool for quality improvement. METHODS: Patient characteristics, intra-operative findings, procedures, and outcomes were assessed in primary advanced stage ovarian cancer cases from 3 independent centers. A surgical complexity score (SCS) was developed to adjust for extent of surgery. Outcomes measures were: 30-day morbidity (sepsis, thrombo-embolic, cardiac, readmission or re-operation), 3-month mortality, length of stay (LOS), and ability to receive chemotherapy. A multivariable risk-adjusted model was developed for all the outcomes. Observed-to-expected (O/E) outcome ratios were calculated from all data. RESULTS: 564 consecutive patients from 3 centers were analyzed. The strongest predictors of 30-day morbidity were endogenous [albumin (p<0.001) and ASA (p=0.008)] and complexity of surgery [SCS (p<0.001)]. Age (p=0.002) and ASA (p=0.001) independently predicted mortality. LOS independently correlated with age (p=0.007), albumin (p=0.004), SCS (p=0.002), and stage (p=0.024). ASA (p<0.001) and SCS (p=0.003) both impacted ability to receive chemotherapy. Observed to expected (O/E) ratios for dependent outcome variables were similar for all 3 institutions. CONCLUSIONS: We demonstrate the benefits of a national system for studying outcomes in gynecologic surgery using a risk-adjusted model. We specifically find that endogenous patient factors and complexity of surgery are primary drivers of morbidity in ovarian cancer surgery. These data can successfully be used to formulate expected, risk-adjusted rates of complications thus providing a meaningful mechanism to identify areas ripe for quality improvement.

Low-dose interleukin-2 administered pre-operatively to patients with gastric cancer activates peripheral and peritumoral lymphocytes but does not affect prognosis.

BACKGROUND: There is evidence that cancer is immunogenic under certain situations. IL-2 is described to stimulate an effective antitumor immune response in vitro and in vivo. The ability of cancer patients to undergo surgical resection is still the most important prognostic factor for many solid tumors, including gastric adenocarcinoma. The host immune system may be further compromised by surgical procedures leading to a generalized state of immunodepression in the post-operative period. The aim of this randomized case-control study is to evaluate the effects of pre-operative low-dose IL-2 treatment on patients with gastric adenocarcinoma who undergo surgery. METHODS: Sixty-eight patients with gastric adenocarcinoma were enrolled in the study and randomized in two groups: 36 patients were pre-treated with IL-2 and 32 underwent surgery without any treatment. Total peripheral WBC, neutrophils, CD3(+) T, CD4(+) T, CD8(+) T and NK cells were obtained before and after surgery, at different times. Peritumoral infiltration was analyzed on all surgical specimens. Overall survival and relapse-free survival were studied with a median follow-up of 51 months. RESULTS: Low-dose IL-2 treatment resulted in an increase peritumoral lymphocytic and eosinophilic infiltrations and in a minor decrease in CD3(+) T and CD4(+) T cells after surgery (P < 0.05). A stepwise multivariate analysis revealed that overall survival and relapse-free survival were affected only by stage of tumor and age of patients. CONCLUSIONS: According to our data low-doses of IL-2 administered pre-operatively to patients with gastric cancer activate peripheral and peri-tumoral lymphocytes but did not affect prognosis.

Myocardial damage prevented by volatile anesthetics: a multicenter randomized controlled study.

OBJECTIVE: The purpose of this study was to evaluate the effects of volatile anesthesia versus total intravenous anesthesia on cardiac troponin release in off-pump coronary artery bypass grafting (OPCAB). DESIGN: The authors performed a multicenter randomized controlled study to compare cardiac troponin release in patients receiving either volatile anesthetics or total intravenous anesthesia for cardiac surgery on the beating heart, which is an excellent model of human myocardial ischemia. SETTING: Three university hospitals. PARTICIPANTS: The authors randomly assigned 57 patients to desflurane (volatile anesthetic) and 55 patients to propofol (intravenous anesthetic) in addition to an opiate-based anesthesia for OPCAB. INTERVENTIONS: The 2 groups of patients received either desflurane (volatile anesthetic) or propofol in addition to an opiate-based anesthesia for OPCAB. Peak postoperative troponin I release was measured as a marker of myocardial necrosis. Prolonged hospitalization was considered as a secondary outcome. MEASUREMENTS AND MAIN RESULTS: Patient mean age was 69 years, and 82% were men. There was a significant (p < 0.001) reduction in postoperative median (25th-75th percentiles) peak of troponin I in patients receiving volatile anesthetics, 1.2 (0.9-1.9) ng/dL, compared with patients receiving total intravenous anesthesia, 2.7 (2.1-4.0) ng/dL. This myocardial protection resulted in a reduced (p = 0.04) number (percentage) of patients requiring postoperative inotropes, 20 (35%) versus 31 (56%), and a reduced number (percentage) of patients submitted to prolonged hospitalization (> or =7 days), 7 (12%) versus 20 (36%) in the 2 groups (p = 0.005). One patient receiving total intravenous anesthesia died within 30 days of surgery. CONCLUSIONS: Myocardial damage measured by cardiac troponin release could be reduced by volatile anesthetics during OPCAB. Because patients underwent cardiac surgery on the beating heart, these results could have implications for cardiac patients undergoing noncardiac surgery.

Perioperative magnesium supplementation to prevent atrial fibrillation after off-pump coronary artery surgery: a randomized controlled study.

OBJECTIVE: Atrial fibrillation is a common complication after cardiac surgery. Magnesium is an effective and safe antiarrhythmic agent for arrhythmias that develop after cardiac surgery. The authors performed a study to evaluate the role of perioperative magnesium for prophylaxis of atrial fibrillation after off-pump coronary artery surgery. DESIGN: Randomized controlled study. SETTING: University teaching hospital. PARTICIPANTS: One hundred sixty consecutive patients undergoing elective, isolated, off-pump coronary artery bypass grafting were prospectively randomized into 2 groups. INTERVENTIONS: Patients in the magnesium group (n = 80) received a 2.5-g (20 mEq) magnesium sulphate infusion intraoperatively over 30 minutes, and the placebo group (n = 80) received normal saline solution. MEASUREMENTS AND MAIN RESULTS: Postoperative atrial fibrillation occurred in 16 of 80 patients (20%) in the magnesium group and in 18 of 80 (22.5%) in the placebo group (p = 0.9). CONCLUSION: The use of 2.5 g of intraoperative magnesium showed no effect in preventing atrial fibrillation after off-pump coronary artery bypass.

Renoprotective action of fenoldopam in high-risk patients undergoing cardiac surgery: a prospective, double-blind, randomized clinical trial.

BACKGROUND: Acute renal failure is a serious complication of cardiac surgery causing high morbidity and mortality. The aim of this study was to evaluate the usefulness of fenoldopam, a specific agonist of the dopamine-1 receptor, in patients at high risk of perioperative renal dysfunction. METHODS AND RESULTS: A prospective single-center, randomized, double-blind trial was performed after local ethical committee approval and after written consent was obtained from 80 patients undergoing cardiac surgery. Patients received either fenoldopam at 0.05 microg/kg per minute or dopamine at 2.5 microg/kg per minute after the induction of anesthesia for a 24-hour period. All these patients were at high risk of perioperative renal dysfunction as indicated by Continuous Improvement in Cardiac Surgery Program score >10. Primary end point was defined as 25% creatinine increase from baseline levels after cardiac surgery. The 2 groups (fenoldopam versus dopamine) were homogeneous cohorts, and no difference in outcome was observed. Acute renal failure was similar: 17 of 40 (42.5%) in the fenoldopam group and 16 of 40 (40%) in the dopamine group (P=0.9). Peak postoperative serum creatinine level, intensive care unit and hospital stay, and mortality were also similar in the 2 groups. CONCLUSIONS: Despite an increasing number of reports of renal protective properties from fenoldopam, we observed no difference in the clinical outcome compared with dopamine in a high-risk population undergoing cardiac surgery.

The incidence and risk of acute renal failure after cardiac surgery.

OBJECTIVE: To evaluate outcome and risk factors of acute renal failure in a surgical population with or without preoperative renal dysfunction. DESIGN: Observational study. SETTING: Intensive care unit at a University Hospital. PARTICIPANTS: Five thousand sixty-eight consecutive adult patients who underwent cardiac surgery with cardiopulmonary bypass. INTERVENTIONS: Perioperative variables measured were age, sex, basic pathology, preoperative renal impairment defined as creatinine >1.4 mg/dL, ventricular dysfunction, preoperative neurologic event, chronic obstructive pulmonary disease, diabetes, type of surgery, use of intra-aortic balloon pump (IABP), cardiopulmonary bypass (CPB) duration, redo or emergency surgery, hemorrhage, blood transfusion, surgical revisions, and postoperative complications. MEASUREMENTS AND MAIN RESULTS: Acute renal failure (100% creatinine increase) developed in 171 (3.4%) patients, whereas 94 patients (1.9% of the population) had renal replacement therapy. Hospital mortality was 40.9% in patients with acute renal failure and increased to 63.8% when renal replacement therapy was requested. Sex, age, emergency surgery, low ejection fraction, IABP device, redo, diabetes, mitral valve surgery, CPB duration, and preoperative renal disease were independently associated with acute renal failure at a multivariate analysis. CONCLUSION: This study confirms that acute renal failure is one of the major complications of cardiac surgery, identifies the risk factors, and suggests that optimizing cardiac output and reducing CPB time could improve the outcome of patients at high risk of acute renal failure.

Clinical significance of a new Q wave after cardiac surgery.

OBJECTIVE: The appearance of new Q waves on the electrocardiogram (ECG) after cardiac surgery has been traditionally considered a sign of major myocardial tissue damage. The aim of this study was to investigate the clinical significance of new Q waves appearing following cardiac surgery and to correlate them with the release of myocardial cell damage biomarkers. METHODS: 206 consecutive patients undergoing cardiac surgery were prospectively evaluated. A 12 lead ECG was recorded and cardiac troponin I and creatinekinase subfraction MB assayed the day before surgery, on arrival at the intensive care Unit. 4 and 18 h postoperatively and every morning until the fifth postoperative day. RESULTS: The incidence of new Q waves was 7.3%. Patients with isolated ECG findings had an uneventful postoperative course; on the contrary, when ECG changes were coupled with the release of myocardial necrosis biomarkers, patients had a complicated postoperative course. CONCLUSIONS: The association of a new Q wave and high levels of myocardial necrosis biomarkers is strongly associated with postoperative cardiac events. On the contrary, the isolated appearance of a new Q wave has no impact on the postoperative cardiac outcome.

ECG changes after CABG: the role of the surgical technique.

OBJECTIVE: The purpose of this study was to determine whether coronary artery bypass grafting (CABG) surgery on the beating heart (BH) is associated with reduction of R-wave potentials on the precordial leads on the surface electrocardiogram (ECG) as previously shown for CABG with cardiopulmonary bypass. METHODS: Fifty-four patients undergoing CABG surgery at a single tertiary care university hospital were analyzed. Patients suffering a postoperative cardiac event (myocardial infarction) or nonspecific ECG changes were excluded. ECG results were recorded at arrival in the intensive care unit, after 4 and 18 hours postoperatively; simultaneously, myocardial cell damage biomarkers (CK-MB and cTnI) were assayed. A control group of 31 patients undergoing mitral valve repair was also evaluated. RESULTS: Patients operated with the BH (OPCABG) technique did not show any decrease of R-wave amplitude at 0, 4, and 18 hours postoperatively; whereas those operated with CPB, both for coronary artery surgery and for mitral repair, had a similar extent and pattern of R-wave reduction. The release of myocardial necrosis markers was significantly lower in coronary artery patients operated with BH than in those operated with CPB; however, no statistically significant correlation between the ECG changes and release of myocardial cell damage markers was observed in any of the groups. CONCLUSIONS: The findings indicate, for the first time, that CABG surgery on the BH is not followed by any reduction of R-wave amplitude on precordial leads and confirms that the BH technique is associated with a lower release of myocardial cell damage markers.

Cardiac biomarker release after CABG with different surgical techniques.

OBJECTIVE: To investigate the release of cardiac biomarkers (troponin I and CK-MB) in patients undergoing coronary artery bypass graft (CABG) with or without cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTING: University tertiary hospital. PARTICIPANTS: Sixty-five consecutive patients undergoing coronary artery bypass grafting (>or=2 vessel disease, ejection fraction >or=0.35%, elective procedure). INTERVENTIONS: Cardiac biomarkers were measured before surgery, at intensive care unit arrival, 4 and 18 hours after the end of the procedure. MEASUREMENTS AND MAIN RESULTS: Cardiac biomarker release was higher in on-pump than in off-pump patients at every time point. On multivariate analysis, CPB (p < 0.0001), number of distal grafts (p = 0.005), and hypertension treatment (p = 0.03) were the only independent predictors of peak cardiac troponin release. CONCLUSIONS: Cardiac troponin I release after multivessel CABG is associated with the technique. Different values for the normal range should be considered. OPCABG is minimally invasive for the heart as far as myocardial marker release is concerned.