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Dive into the research topics where John M. Karamichalis is active.

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Featured researches published by John M. Karamichalis.


The Journal of Thoracic and Cardiovascular Surgery | 2012

Surgical technical performance scores are predictors of late mortality and unplanned reinterventions in infants after cardiac surgery

Meena Nathan; John M. Karamichalis; Hua Liu; Sitaram M. Emani; Christopher W. Baird; Frank A. Pigula; Steven D. Colan; Ravi R. Thiagarajan; Emile A. Bacha; Pedro J. del Nido

OBJECTIVE We have previously shown that surgical Technical Performance Scores (TPS) are important predictors of early postoperative morbidity across a wide spectrum of procedures and that intraoperative recognition and intervention of residual defects resulted in improved outcomes. We hypothesized that these scores would also be important predictors of midterm outcomes. METHODS Neonates and infants aged younger 6 months were prospectively followed from the index surgery for a minimum of 1 year. The TPS were calculated using previously published criteria, including intraoperative course, predischarge echocardiograms or catheterizations, and clinical data, and graded as optimal, adequate, or inadequate. Case complexity was determined by the Risk Adjustment for Congenital Heart Surgery-1 category. The primary outcome was mortality, and the secondary outcome was the need for unplanned reinterventions. Outcomes were analyzed using nonparametric methods and a logistic regression model. RESULTS A total of 166 patients were included in our study, with 7 early deaths. The remaining 159 patients (Risk Adjustment for Congenital Heart Surgery-1 category 4-6, 76 [48%]; neonates, 78 [49%]) were followed for a minimum of 1 year after surgery. There were 14 late deaths or late transplantations and 55 late reinterventions. On univariate analysis, the TPS were associated with mortality (P < .001) and reintervention (P = .04). On logistic regression analysis, inadequate TPS was associated with late mortality (P < .001; odds ratio, 7.2; 95% confidence interval, 2.2-23.6), and Risk Adjustment for Congenital Heart Surgery-1 category (P = .004; odds ratio, 3.7; 1.5-8.8) at index surgery was associated with need for late unplanned reintervention. CONCLUSIONS Technical performance affects midterm survival after infant heart surgery. Inadequate TPS can be used to prospectively identify patients at ongoing risk of demise and the need for reintervention. An aggressive approach to diagnosing and treating residual lesions at the initial operation is warranted.


The Journal of Thoracic and Cardiovascular Surgery | 2011

Intraoperative adverse events can be compensated by technical performance in neonates and infants after cardiac surgery: A prospective study

Meena Nathan; John M. Karamichalis; Hua Liu; Pedro J. del Nido; Frank A. Pigula; Ravi R. Thiagarajan; Emile A. Bacha

OBJECTIVE Our objective was to define the relationship between surgical technical performance score, intraoperative adverse events, and major postoperative adverse events in complex pediatric cardiac repairs. METHOD Infants younger than 6 months were prospectively followed up until discharge from the hospital. Technical performance scores were graded as optimal, adequate, or inadequate based on discharge echocardiograms and need for reintervention after initial surgery. Case complexity was determined by Risk Adjustment in Congenital Heart Surgery (RACHS-1) category, and preoperative illness severity was assessed by Pediatric Risk of Mortality (PRISM) III score. Intraoperative adverse events were prospectively monitored. Outcomes were analyzed using nonparametric methods and a logistic regression model. RESULTS A total of 166 patients (RACHS 4-6 [49%]), neonates [50%]) were observed. Sixty-one (37%) had at least 1 intraoperative adverse event, and 47 (28.3%) had at least 1 major postoperative adverse event. There was no correlation between intraoperative adverse events and RACHS, preoperative PRISM III, technical performance score, or postoperative adverse events on multivariate analysis. For the entire cohort, better technical performance score resulted in lower postoperative adverse events, lower postoperative PRISM, and lower length of stay and ventilation time (P < .001). Patients requiring intraoperative revisions fared as well as patients without, provided the technical score was at least adequate. CONCLUSIONS In neonatal and infant open heart repairs, technical performance score is one of the main predictors of postoperative morbidity. Outcomes are not affected by intraoperative adverse events, including surgical revisions, provided technical performance score is at least adequate.


The Journal of Thoracic and Cardiovascular Surgery | 2010

Stage I Norwood: Optimal technical performance improves outcomes irrespective of preoperative physiologic status or case complexity

John M. Karamichalis; Ravi R. Thiagarajan; Hua Liu; Petra Mamic; Kimberlee Gauvreau; Emile A. Bacha

OBJECTIVE Interplay of baseline physiologic status, case complexity, technical performance, and outcomes in high-acuity operations has been poorly defined. This study explored these interactions to determine whether a technically optimal operation can mitigate effects of baseline physiology and high case-complexity on outcomes for the stage I Norwood procedure. METHODS Technical performance was categorized as optimal, adequate, or inadequate from adequacy of the anatomic repair of the stage I subprocedures according to anatomic areas where intervention is performed. Physiological illness severity statuses in preoperative and postoperative periods were determined with Pediatric Risk of Mortality III system, which uses 17 physiologic variables. Case complexity was calculated with Aristotle comprehensive system. All patients undergoing stage I procedure from January 2004 to December 2007 were retrospectively studied. RESULTS One hundred thirty-five procedures were included. Five were excluded from the technical performance assessment because of inadequate postoperative data. Eighty-one (62.3%), 26 (20%), and 23 (17.7%), respectively, were scored as optimal, adequate, and inadequate. Overall hospital mortality was 14.1%. Inadequate technical performance, high-complexity Aristotle comprehensive scores, and high preoperative illness severity scores correlated with significantly higher hospital mortality, longer stay, and greater frequency of major postoperative complications. In subgroup analysis of patients with optimal technical performance, outcomes were favorable irrespective of high or low preoperative physiologic illness severity or case complexity. CONCLUSIONS In stage I Norwood procedures, optimal technical performance attenuated effects of poor preoperative physiologic status and high case complexity, with reduced hospital mortality. Inadequate technical performance resulted in poor outcomes regardless of preoperative status.


The Annals of Thoracic Surgery | 2011

Early Postoperative Severity of Illness Predicts Outcomes After the Stage I Norwood Procedure

John M. Karamichalis; Pedro J. del Nido; Ravi R. Thiagarajan; Kathy J. Jenkins; Hua Liu; Kimberlee Gauvreau; Frank A. Pigula; Francis Fynn-Thompson; Sitaram M. Emani; John E. Mayer; Emile A. Bacha

BACKGROUND We hypothesize that a measure of the immediate postoperative severity of illness after the stage I Norwood operation reflects technical performance or the adequacy of anatomic repair and can serve as a predictor of hospital mortality, reinterventions, and clinical outcomes. METHODS One hundred thirty-five patients undergoing stage I were retrospectively studied (2004 to 2007). The severity of illness on postoperative day 1 (POD1) was measured using the Pediatric Risk of Mortality III (PRISM) scoring system. Technical performance scores (optimal, adequate, inadequate) were calculated before hospital discharge. Hospital mortality, postoperative reinterventions, and complications were recorded. Postoperative reintervention was defined as need for cardiac catheterization laboratory or operating room based procedure that included balloon dilation or repair of arch obstruction, shunt revision, reoperations for bleeding, and extracorporeal membrane oxygenation support. RESULTS Hospital mortality was 14.1% (n=19). The rate of complications and reinterventions was, respectively, 28.1% (n=38) and 26.7% (n=36). The POD1 PRISM score was associated with technical performance (p=0.003). Higher POD1 PRISM scores were associated with mortality (p<0.001), complications (p<0.001), and reinterventions (p=0.001). The POD1 PRISM score had high discrimination for mortality, complications, reinterventions, and inadequate technical performance (areas under the receiver operating characteristic curve were 0.835, 0.776, 0.773, and 0.710, respectively; p≤0.001 for all). CONCLUSIONS The severity of illness as measured by PRISM score on POD1 after the stage I Norwood operation has strong association and discrimination with hospital mortality, postoperative reinterventions, inadequate technical performance, and major postoperative complications. It may be used as an early surrogate of technical performance to initiate a search for and correction of technical deficiencies.


The Annals of Thoracic Surgery | 2012

Technical Performance Scores in Congenital Cardiac Operations: A Quality Assessment Initiative

John M. Karamichalis; Steven D. Colan; Meena Nathan; Frank A. Pigula; Christopher W. Baird; Gerald R. Marx; Sitaram M. Emani; Tal Geva; Francis Fynn-Thompson; Hua Liu; John E. Mayer; Pedro J. del Nido

BACKGROUND Technical performance in congenital cardiac operations and its association with clinical outcomes was previously examined in infants and neonates. The purpose of this study was the development and implementation of a system for measuring technical performance in the majority of congenital cardiac operations to be used as a surgeons self-assessment tool. METHODS Using the methodologic framework piloted at our institution, measures of technical performance were created for more than 90% of all congenital cardiac operations. Each operation was divided into multiple subprocedures to be assessed separately. Criteria for technical scores were created using a consensus panel of senior clinicians and were based primarily on the predischarge echocardiographic findings and need for early postoperative reinterventions. This system of procedure modules was then piloted by prospectively assigning technical scores to all patients undergoing operations. RESULTS Thirty modules were created covering more than 90% of the cardiac operations performed. One hundred eighty-five patients were enlisted. One hundred one (54.6%) cases were scored as class 1 (highest), 46 (24.9%) cases as class 2, 22 (11.9%) cases as class 3 (lowest); 16 cases (8.6%) could not be scored. The results were further analyzed by RACHS (Risk Adjustment for Congenital Heart Surgery) categories and outcomes. Valve-procedure-specific criteria were calibrated to reflect specific echocardiographic measurements. CONCLUSIONS The development and implementation of a broad technical performance self-assessment system for congenital cardiac operations is possible. Based on this scoring system, the impact of a less than optimal (2 or 3) technical score depends on case risk category, with higher mortality in the higher risk group, and increased resource use for lower risk procedures.


The Journal of Thoracic and Cardiovascular Surgery | 2014

Technical Performance Scores are strongly associated with early mortality, postoperative adverse events, and intensive care unit length of stay—analysis of consecutive discharges for 2 years

Meena Nathan; John M. Karamichalis; Hua Liu; Kimberley Gauvreau; Steven D. Colan; Matthew Saia; Frank A. Pigula; Francis Fynn-Thompson; Sitaram M. Emani; Christopher W. Baird; John E. Mayer; Pedro J. del Nido


The Journal of Thoracic and Cardiovascular Surgery | 2018

Surgical relief of left ventricular outflow obstruction in pediatric hypertrophic cardiomyopathy: The need for a tailored approach

John M. Karamichalis; Heba Aguib; Alexandra Anastasopulos; Magdi H. Yacoub


The Journal of Thoracic and Cardiovascular Surgery | 2018

Innovation and science: The future of valve design

John M. Karamichalis; Peter E. Hammer


The Journal of Thoracic and Cardiovascular Surgery | 2017

Designing valves: An art or science?

John M. Karamichalis; Peter E. Hammer


The Journal of Thoracic and Cardiovascular Surgery | 2016

Can we prevent poor outcomes for children who require long intensive care stays or early reoperations

John M. Karamichalis

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Hua Liu

Boston Children's Hospital

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Frank A. Pigula

Boston Children's Hospital

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Pedro J. del Nido

Boston Children's Hospital

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Meena Nathan

Boston Children's Hospital

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Sitaram M. Emani

Boston Children's Hospital

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John E. Mayer

Boston Children's Hospital

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Steven D. Colan

Boston Children's Hospital

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