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1.  Variation in Outcomes for Risk-Stratified Pediatric Cardiac Surgical Operations: An Analysis of the STS Congenital Heart Surgery Database 
The Annals of thoracic surgery  2012;94(2):564-572.
We evaluated outcomes for groups of risk-stratified operations in The Society of Thoracic Surgeons Congenital Heart Surgery Database to provide contemporary benchmarks and examine variation between centers.
Patients undergoing surgery from 2005 to 2009 were included. Centers with more than 10% missing data were excluded. Discharge mortality and postoperative length of stay (PLOS) among patients discharged alive were calculated for groups of risk-stratified operations using the five Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery Congenital Heart Surgery mortality categories (STAT Mortality Categories). Power for analyzing between-center differences in outcome was determined for each STAT Mortality Category. Variation was evaluated using funnel plots and Bayesian hierarchical modeling.
In this analysis of risk-stratified operations, 58,506 index operations at 73 centers were included. Overall discharge mortality (interquartile range among programs with more than 10 cases) was as follows: STAT Category 1 = 0.55% (0% to 1.0%), STAT Category 2 = 1.7% (1.0% to 2.2%), STAT Category 3 = 2.6% (1.1% to 4.4%), STAT Category 4 = 8.0% (6.3% to 11.1%), and STAT Category 5 = 18.4% (13.9% to 27.9%). Funnel plots with 95% prediction limits revealed the number of centers characterized as outliers by STAT Mortality Categories was as follows: Category 1 = 3 (4.1%), Category 2 = 1 (1.4%), Category 3 = 7 (9.7%), Category 4 = 13 (17.8%), and Category 5 = 13 (18.6%). Between-center variation in PLOS was analyzed for all STAT Categories and was greatest for STAT Category 5 operations.
This analysis documents contemporary benchmarks for risk-stratified pediatric cardiac surgical operations grouped by STAT Mortality Categories and the range of outcomes among centers. Variation was greatest for the more complex operations. These data may aid in the design and planning of quality assessment and quality improvement initiatives.
PMCID: PMC4006082  PMID: 22704799
2.  Structural Transition from Helices to Hemihelices 
PLoS ONE  2014;9(4):e93183.
Helices are amongst the most common structures in nature and in some cases, such as tethered plant tendrils, a more complex but related shape, the hemihelix forms. In its simplest form it consists of two helices of opposite chirality joined by a perversion. A recent, simple experiment using elastomer strips reveals that hemihelices with multiple reversals of chirality can also occur, a richness not anticipated by existing analyses. Here, we show through analysis and experiments that the transition from a helical to a hemihelical shape, as well as the number of perversions, depends on the height to width ratio of the strip's cross-section. Our findings provides the basis for the deterministic manufacture of a variety of complex three-dimensional shapes from flat strips.
PMCID: PMC3997338  PMID: 24759785
World journal for pediatric & congenital heart surgery  2013;4(1):10.1177/2150135112461924.
Several distinct definitions of postoperative death have been used in various quality reporting programs. Some have defined a postoperative mortality as a patient who expires while still in the hospital, while others have considered all deaths occurring within a predetermined, standardized time interval after surgery. While if continues to collect mortality data using both these individual definitions, the Society of Thoracic Surgeons (STS) believes that either alone may be inadequate. Accordingly, the STS prefers a more encompassing metric, Operative Mortality, which is defined as (1) all deaths occurring during the hospitalization in which the operation was performed, even if after 30 days; and (2) all deaths occurring after discharge from the hospital, but before the end of the thirtieth postoperative day. This manuscript provides clarification for some uncommon but important scenarios where the correct application of this definition may be problematic.
PMCID: PMC3828200  PMID: 23799748
cardiac disease; thoracic disease; congenital heart disease; outcomes analysis; quality improvement; database; mortality
4.  An empirically based tool for analyzing morbidity associated with operations for congenital heart disease 
The Journal of thoracic and cardiovascular surgery  2012;145(4):10.1016/j.jtcvs.2012.06.029.
Congenital heart surgery outcomes analysis requires reliable methods of estimating the risk of adverse outcomes. Contemporary methods focus primarily on mortality or rely on expert opinion to estimate morbidity associated with different procedures. We created an objective, empirically based index that reflects statistically estimated risk of morbidity by procedure.
Morbidity risk was estimated using data from 62,851 operations in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2002-2008). Model-based estimates with 95% Bayesian credible intervals were calculated for each procedure’s average risk of major complications and average postoperative length of stay. These 2 measures were combined into a composite morbidity score. A total of 140 procedures were assigned scores ranging from 0.1 to 5.0 and sorted into 5 relatively homogeneous categories.
Model-estimated risk of major complications ranged from 1.0% for simple procedures to 38.2% for truncus arteriosus with interrupted aortic arch repair. Procedure-specific estimates of average postoperative length of stay ranged from 2.9 days for simple procedures to 42.6 days for a combined atrial switch and Rastelli operation. Spearman rank correlation between raw rates of major complication and average postoperative length of stay was 0.82 in procedures with n greater than 200. Rate of major complications ranged from 3.2% in category 1 to 30.0% in category 5. Aggregate average postoperative length of stay ranged from 6.3 days in category 1 to 34.0 days in category 5.
Complication rates and postoperative length of stay provide related but not redundant information about morbidity. The Morbidity Scores and Categories provide an objective assessment of risk associated with operations for congenital heart disease, which should facilitate comparison of outcomes across cohorts with differing case mixes.
PMCID: PMC3824389  PMID: 22835225
5.  Initial application in the EACTS and STS Congenital Heart Surgery Databases of an empirically derived methodology of complexity adjustment to evaluate surgical case mix and results† 
Outcomes evaluation is enhanced by assignment of operative procedures to appropriate categories based upon relative average risk. Formal risk modelling is challenging when a large number of operation types exist, including relatively rare procedures. Complexity stratification provides an alternative methodology. We report the initial application in the Congenital Heart Surgery Databases of the Society of Thoracic Surgeons (STS) and the European Association for Cardio-thoracic Surgery (EACTS) of an empirically derived system of complexity adjustment to evaluate surgical case mix and results.
Complexity stratification is a method of analysis in which the data are divided into relatively homogeneous groups (called strata). A complexity stratification tool named the STS–EACTS Congenital Heart Surgery Mortality Categories (STAT Mortality Categories) was previously developed based on the analysis of 77 294 operations entered in the Congenital Heart Surgery Databases of EACTS (33 360 operations) and STS (43 934 patients). Procedure-specific mortality rate estimates were calculated using a Bayesian model that adjusted for small denominators. Operations were sorted by increasing risk and grouped into five categories (the STAT Mortality Categories) that were designed to minimize within-category variation and maximize between-category variation. We report here the initial application of this methodology in the EACTS Congenital Heart Surgery Database (47 187 operations performed over 4 years: 2006–09) and the STS Congenital Heart Surgery Database (64 307 operations performed over 4 years: 2006–09).
In the STS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1–5 were (1): 17332, (2): 20114, (3): 9494, (4): 14525 and (5): 2842. Discharge mortality was (1): 0.54%, (2): 1.6%, (3): 2.4%, (4): 7.5% and (5): 17.8%. In the EACTS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1–5 were (1): 19874, (2): 12196, (3): 5614, (4): 8287 and (5): 1216. Discharge mortality was (1): 0.99%, (2): 2.9%, (3): 5.0%, (4): 10.3% and (5): 25.0%.
The STAT Mortality Categories facilitate analysis of outcomes across the wide spectrum of distinct congenital heart surgery operations including infrequently performed procedures.
PMCID: PMC3858079  PMID: 22700597
Database; Outcomes; Quality assessment; Quality improvement
6.  Performance of Cavopulmonary Palliation at Elevated Altitude 
Circulation  2008;118(14 Suppl):S177-S181.
Outcomes of patients undergoing cavopulmonary palliation for single ventricle physiology may be impacted by living at altitude, as the passive pulmonary circulation is dependent on the resistance of the pulmonary vascular bed. The objective of this study is to identify risk factors for failure of cavopulmonary palliation at elevated altitude.
Methods and Results
Between January 1995 and March 2007, 122 consecutive patients living at a mean altitude of 1600 m (range 305 to 2570) underwent a bidirectional Glenn (BDG). There was one in-hospital mortality and 7 late deaths. 52 have proceeded to the Fontan procedure. Survival after BDG was 92.4% at 5 years. Freedom from palliation failure, defined as death, transplant, BDG/Fontan takedown, or revision was 81% at 5 years. At a mean follow-up of 39.8 months, 90 patients (75%) were in New York Heart Association class I. Patients with failing cavopulmonary circulation had higher pre-BDG pulmonary artery pressure (PAP) (18.3±6.1 mm Hg versus 14.8±5.1 mm Hg, P=0.016) and higher pre-BDG transpulmonary gradient (TPG) (11.2±6.2 mm Hg versus 7.7±4.3 mm Hg, P=0.014). Post-BDG, patients with palliation failure had increased PAP (15.0±5.7 mm Hg versus 10.8±2.8 mm Hg, P=0.008) and indexed pulmonary vascular resistance (PVRI) (2.43±1.0 Wood U · m2 versus 1.52±0.9 Wood U · m2, P=0.007).
The majority of patients at moderate altitude have favorable outcomes after BDG or Fontan palliation. Risk factors for palliation failure at elevated altitude include PAP >15 mm Hg, TPG >8 mm Hg, and PVRI >2.5 Wood U · m2.
PMCID: PMC3129266  PMID: 18824752
Fontan procedure; single ventricle; altitude
7.  Outcomes of Reparative and Transplantation Strategies for Multilevel Left Heart Obstructions With Mitral Stenosis 
The Annals of thoracic surgery  2008;86(4):1305-1310.
Conventional management for multilevel left heart obstructions and mitral stenosis (Shone’s complex) involves multiple operations that carry additive risks. This study reviews our experience with reconstructive and transplantation approaches for Shone’s complex.
Between 1987 and 2007, 43 patients with mitral stenosis and one or more left-sided obstructions were identified: supramitral ring (n = 13), subaortic stenosis (n = 25), aortic stenosis (n = 24), hypoplastic arch (n = 20), and coarctation (n = 38). Thirty patients underwent a staged reparative approach, including 27 mitral and 51 left ventricular outflow tract operations. Thirteen patients were referred for transplantation. Patients with severe hypoplasia of the left ventricle were excluded.
There was one in-hospital death (2.5%) and six late deaths (14.2%). Actuarial 5- and 10-year survival for staged surgical and transplantation was 88% vs 61.3% and 83.1% vs 61.3% (p = 0.035). At a mean follow-up of 7.9 years, freedom from mitral reoperation was 83.3% and freedom from reoperation for subaortic stenosis was 78.0%. Wait-list mortality was 13.3% (2 of 13). Wait-list time exceeding 90 days was an incremental risk factor for death after transplantation (p = 0.005).
Despite the challenges of a reparative strategy for Shone’s complex, favorable survival and durability outcomes can be expected. Heart transplantation, although avoiding the pitfalls of staged repair, confers increased risks from ongoing physiologic derangements due to uncorrected left heart inflow and outflow obstructions during the wait for donor heart availability.
PMCID: PMC3128450  PMID: 18805182
8.  Implications of incising the ventricular septum in double outlet right ventricle and in the Ross–Konno operation☆ 
Incision into the ventricular septum in complex biventricular repair is controversial, and has been blamed for impairing left ventricular function. This retrospective study evaluates the risk of a ventricular septal incision in patients undergoing double outlet right ventricle (DORV) repair and Ross–Konno procedure.
From January 2003 to September 2007, 11 patients with DORV had a ventricular septum (VS) incision and 12 DORV patients did not. Sixteen patients had a Ross–Konno, and 16 had an isolated Ross procedure. The ventricular septal incision was made to match at least the diameter of a normal aortic annulus. In DORV, the VSD was enlarged superiorly and to the left. In the Ross–Konno, the aortic annulus was enlarged towards the septum posteriorly and to the left.
The median follow-up for the study is 19 months (1 month–4 years). For DORV, there were no significant differences in discharge mortality ( p = 0.22), late mortality ( p = 0.48), or late mortality plus heart transplant ( p = 0.093). Although patients with DORV and VSD enlargement have a more complex postoperative course, there were no differences in ECMO use ( p = 0.093), occurrence of permanent AV block ( p = 0.55), left ventricular ejection fraction (LVEF) ( p = 0.40), or shortening fraction (LVSF) ( p = 0.50). Similarly, for the Ross–Konno there were no significant differences in discharge mortality ( p = 0.30), late mortality ( p = NS), LVEF (p = 0.90) and LVSF ( p = 0.52) compared to the Ross, even though the Ross–Konno patients were significantly younger ( p < 0.0001).
Making a ventricular septal incision in DORV repair and in the Ross–Konno operation does not increase mortality and does not impair the LV function. The restriction of the VSD remains an important issue in the management of complex DORV. These encouraging results need to be confirmed by larger series.
PMCID: PMC3117298  PMID: 19269838
Double outlet right ventricle; Ventricular septal defect; Ross–Konno

Results 1-9 (9)