Repair Of Complete Atrioventricular Canal Research Articles

Predictors of post-operative left atrioventricular valve regurgitation in pediatric patients with complete atrioventricular canal defects.

In infants with complete atrioventricular canal (CAVC) defects, post-operative left atrioventricular valve regurgitation (LAVVR) is a known major cause of morbidity and mortality and a common indication for re-operation. However, there is scarce data to identify risk factors for poor outcomes. Our study aims to find echocardiographic characteristics that predict post-operative LAVVR at discharge and 1-year follow-up. Retrospective cohort study of patients with initial CAVC repair at our hospital who were followed for 1 year between 2013 and 2022. Patients with major co-morbid conditions were excluded. Serial echocardiograms were reviewed. Anatomic details, quantitative and qualitative measure of LAVVR including the number of regurgitant jets, regurgitant jet length and vena contracta width, and ventricular function were collected. The time points measured include pre-operative transthoracic echocardiogram (TTE), post-operative transesophageal echocardiogram (PO-TEE), routine protocol based post-operative day 1 (POD1) TTE, discharge TTE and 1-year post-operative (1yPO) TTE. Paired t-tests, chi-square analysis, and linear regression analysis were performed comparing measured variables to LAVVR outcomes. Fifty-two patients were included; 92% had Trisomy 21. The majority were classified as Rastelli A (71%), others Rastelli C (29%). Only two patients had moderate or greater LAVVR pre-operatively. The mean age at repair was 125 ± 44 days. Pre-operative LAVVR was the only significant predictor of LAVVR severity at 1 year after backward stepwise regression. Of those with<moderate LAVVR on PO-TEE, 20% had worsening to≥moderate at discharge, but only 9% remained that way at 1 year. Of those with≥moderate LAVVR on PO-TEE, 40% improved to<moderate by 1 year. Two patients who worsened at 1 year, both secondary to likely cleft suture dehiscence. Only one patient required reoperation in the immediate post-operative period secondary to severe LAVVR due to suture dehiscence. Routine protocol-based POD1 echo did not have any association with altered outcomes. Pre-operative LAVVR was the only significant predictor of LAVVR severity at 1 year. A significant percentage (40%) of patient with≥moderate LAVVR on PO-TEE improved to<moderate by 1 year. Furthermore, routine protocol-based POD1 echo did not have any association with altered outcomes.

Anatomic considerations in the management of complete atrioventricular canal.

Patients with complete atrioventricular canal have a variable clinical course prior to repair. Many patients balance their circulations well prior to elective repair. Others manifest clinically significant pulmonary over circulation early in life and require either palliative pulmonary artery banding or complete repair. The objective of this study was to assess anatomic features that impact the clinical course of patients. In total, 222 patients underwent complete atrioventricular canal repair between 2012 and 2022 at a single institution. Twenty-seven (12%) patients underwent either pulmonary artery banding (n = 15) or complete repair (n = 12) at less than 3 months of age (Group 1). The remaining 195 (88%) underwent repair after 3 months of age (Group 2). Patient records and imaging were reviewed. The median post-operative length of stay following complete repair was 25 [7,46] days for those patients in Group 1 and 7 [5,12] days for those in Group 2 (p < 0.0001). There was relative hypoplasia of left-sided structures in Group 1 versus Group 2. Mean z-score for the ascending aorta was -1.2 (±0.8) versus -0.3 (±0.9) (p < 0.0001), the aortic isthmus was -2.1 (±0.8) versus -1.4 (±0.8) (p = 0.005). The pulmonary valve to aortic valve diameter ratio was median 1.47 [1.38,1.71] versus 1.38 [1.17,1.53] (p 0.008). Echocardiographic evaluation of the systemic and pulmonary outflow of patients with complete atrioventricular canal may assist in predicting the clinical course and need for early repair vs pulmonary artery banding.

Outcomes after repair of complete atrioventricular canal with a modified single-patch technique: a retrospective study.

This study aimed to present the short- and midterm outcomes after complete atrioventricular canal defect (CAVC) repair using a single-patch technique. This study included 30 children who underwent surgical correction of the CAVC using a single-patch technique. The median age of the patients was 5.7 months (interquartile range [IQR], 5.0-7.5 months), and 23 patients (76.7%) had type A CAVC. Fourteen patients (46.7%) were female and 17 (56.7%) had been diagnosed with Down syndrome. The in-hospital mortality rate was 0%. No deaths were observed during a median follow-up of 4 years (IQR, 3.5-5.0 years). Patients without Down syndrome were associated with late moderate mitral regurgitation (MR) (p=0.02). Late MR less than moderate degree was observed in 96.6%, 78.5%, and 50% of patients after 2, 4, and 5 years of follow-up, respectively, while late tricuspid valve regurgitation less than moderate degree was observed in 96.7%, 85.9%, and 59.0% of patients after 2, 4, and 6 years of follow-up, respectively. After a median follow-up of 4 years, only one patient had required surgical repair of a left ventricular outflow tract obstruction, which occurred 26 months after the first operation. Multivariable logistic regression analysis adjusted for the type of CAVC, sex, Down syndrome, age, and weight revealed that the absence of Down syndrome was a risk factor for late moderate MR (MR-2) (odds ratio, 0.05; 95% confidence interval, 0.006-0.50; p=0.01). A single-patch technique for CAVC surgical repair is a safe method with acceptable short- and midterm results.

Predictors of increased postoperative length of stay after complete atrioventricular canal repair.

The optimal timing of surgical repair for infants with complete atrioventricular canal defect remains controversial, as there are risks to both early and late repair. We address this debate by investigating the association of various risk factors, including age and weight at surgery, markers of failure to thrive, and pulmonary vascular disease, with postoperative length of stay following complete atrioventricular canal repair. Infants who underwent repair of complete atrioventricular canal were identified from our institutional Society of Thoracic Surgeons Congenital Heart Surgery Database. Additional clinical data were collected from the electronic medical record. Descriptive statistics were computed. Associations between postoperative length of stay and covariates of interest were evaluated using linear regression with bootstrap aggregation. From 2001 to 2020, 150 infants underwent isolated complete atrioventricular canal repair at our institution. Pre-operative failure to thrive and evidence of pulmonary disease were common. Surgical mortality was 2%. In univariable analysis, neither weight nor age at surgery were associated with mortality, postoperative length of stay, duration of mechanical ventilation, or post-operative severe valvular regurgitation. In multivariable analysis of demographic and preoperative clinical factors using bootstrap aggregation, increased postoperative length of stay was only significantly associated with previous pulmonary artery banding (33.9 day increase, p = 0.03) and preoperative use of supplemental oxygen (19.9 day increase, p = 0.03). Our analysis shows that previous pulmonary artery banding and preoperative use of supplemental oxygen were associated with increased postoperative length of stay after complete atrioventricular canal repair, whereas age and weight were not. These findings suggest operation prior to the onset of pulmonary involvement may be more important than reaching age or weight thresholds.

Visualization and Quantification of the Unrepaired Complete Atrioventricular Canal Valve Using Open-Source Software

Repair of complete atrioventricular canal (CAVC) is often complicated by residual left atrioventricular valve regurgitation. The structure of the mitral and tricuspid valves in biventricular hearts has previously been shown to be associated with valve dysfunction. However, the three-dimensional (3D) structure of the entire unrepaired CAVC valve has not been quantified. Understanding the 3D structure of the CAVC may inform optimized repair. Novel open-source work flows were created in SlicerHeart for the modeling and quantification of CAVC valves on the basis of 3D echocardiographic images. These methods were applied to model the annulus, leaflets, and papillary muscle (PM) structure of 35 patients (29 with trisomy 21) with CAVC using transthoracic 3D echocardiography. The mean leaflet and annular shapes were calculated and visualized using shape analysis. Metrics of the complete native CAVC valve structure were compared with those of normal mitral valves using the Mann-Whitney U test. Associations between CAVC structure and atrioventricular valve regurgitation were analyzed. CAVC leaflet metrics varied throughout systole. Compared with normal mitral valves, the left CAVC PMs were more acutely angled in relation to the annular plane (P<.001). In addition, the anterolateral PM was laterally and inferiorly rotated in CAVC, while the posteromedial PM was more superiorly and laterally rotated, relative to normal mitral valves (P<.001). Lower native CAVC atrioventricular valve annular height and annular height-to-valve width ratio before repair were both associated with moderate or greater left atrioventricular valve regurgitation after repair (P<.01). It is feasible to model and quantify 3D CAVC structure using 3D echocardiographic images. The results demonstrate significant variation in CAVC structure across the cohort and differences in annular, leaflet, and PM structure compared with the mitral valve. These tools may be used in future studies to catalyze future research intended to identify structural associations of valve dysfunction and to optimize repair in this vulnerable and complex population.

Abstract 13689: The Center-Volume Effect on Congenital Heart Surgery Revised: Is It Time to Consider Regionalization of Care?

Introduction: Regionalization of congenital heart surgery (CHS) has been debated in the U.S. and other countries. Previous reports demonstrated a variable effect of a center’s volume on in-hospital postoperative mortality. However, the volume-outcome relationship for CHS remains incompletely understood without considering outcomes beyond hospital discharge. Hypothesis: We sought to determine, whether procedure-specific center volume predicts postoperative mortality for infants undergoing three complex benchmark procedures (Norwood procedure, arterial switch operation and complete atrioventricular canal repair) and used ventricular septal defect (VSD) closure as a simple benchmark procedure comparison. Methods: We used data from the Pediatric Cardiac Care Consortium, a multi-center U.S.-based clinical registry of CHS, enriched with post-discharge death data after linkage with the National Death Index. We used generalized estimating equations to assess the association between procedure-specific volume and mortality from the time of CHS and up to three years after CHS. Models were adjusted for patient age and weight at CHS, presence of a chromosomal abnormality, and surgical era and accounted for clustering at the center-level. Results: Analysis included 6,656 infants operated at 42 centers between 1982 and 2003. We found an absolute reduction in post-operative risk of death ranging from 6-12% for every additional surgery performed in the same center for Norwood, ASO, and CAVC repair and at all time points examined (Table). There was no statistically significant association between VSD center volume and mortality at any time point. Conclusions: In-hospital and longer-term survival after infantile CHS is improved with increased center case volume for complex CHS. These findings support the regionalization of complex CHS in the U.S.. Decision-makers should consider feasibility of such regionalization to improve outcomes after complex CHS.

Dosing of Opioid Medications During and After Pediatric Cardiac Surgery for Children With Down Syndrome

To determine whether children with Down syndrome (DS) receive higher doses of opioid medications compared with children without DS for repair of complete atrioventricular canal (CAVC). A retrospective chart review of children with and without DS who underwent primary repair of CAVC. The exclusion criteria included unbalanced CAVC and patients undergoing biventricular staging procedures. The primary outcome was oral morphine equivalents (OME) received in the first 24 hours after surgery. The secondary outcomes included intraoperative OME, OME at 48 and 72 hours, nonopioid analgesic and sedative medications received, pain scores, time to extubation, and length of stay. A pediatric academic medical center in the United States. One hundred thirty-one patients with DS and 24 without, all <two years old, who underwent a CAVC repair. Not applicable. Patients with DS were older than patients without DS (median 96.3 days [interquartile range {IQR} 70.7-128.2] v 75.9 days [IQR 49.8-107.3], p=0.033) but otherwise not statistically different in the baseline characteristics. There was no difference in OME received in the first 24 hours postoperatively between groups (3.01 mg/kg [IQR 1.23-5.43] v 3.57 mg/kg [IQR 1.54-7.06], p=0.202). OME at 48 and 72 hours was lower in the DS group compared with the control group. Similar amounts of opioid and non-opioid analgesics and sedatives were otherwise given to both groups of patients. Median pain scores did not differ between groups. These results suggested that patients with DS undergoing CAVC repair do not have increased opioid requirements compared with a similar control group.

The Characterization of Postoperative Mechanical Respiratory Requirement in Neonates and Infants Undergoing Cardiac Surgery on Cardiopulmonary Bypass in a Single Tertiary Institution

Although neonates and infants undergoing cardiac surgery on cardiopulmonary bypass (CPB) are at high risk of developing perioperative morbidity and mortality, including lung injury, the intraoperative profile of lung injury in this cohort is not well-described. Given that the postoperative course of patients in the pediatric cardiac surgical arena has become increasingly expedited, the objective of this study was to characterize the profiles of postoperative mechanical ventilatory support in neonates and infants undergoing cardiac surgery on CPB and to examine the characteristics of lung mechanics and lung injury in this patient population who are potentially amendable to early postoperative recovery in a single tertiary pediatric institution. A retrospective data analysis of neonates and infants who underwent cardiac surgery on cardiopulmonary bypass. A single-center, university teaching hospital. The study included 328 neonates and infants who underwent cardiac surgery on cardiopulmonary bypass. A subset of 128 patients were studied: 58 patients undergoing ventricular septal defect (VSD) repair, 36 patients undergoing complete atrioventricular canal (CAVC) repair, and 34 patients undergoing bidirectional Glenn (BDG) shunt surgery. Of the entire cohort, 3.7% experienced in-hospital mortality. Among all surgical procedures, VSD repair (17.7%) was the most common, followed by CAVC repair (11.0%) and BDG shunt surgery (10.4%). Of patients who underwent VSD repair, CAVC repair, and BDG shunt surgery, 65.5%, 41.7%, and 67.6% were off mechanical ventilatory support within 24 hours postoperatively, respectively. In all three of the surgical repairs, lung compliance decreased after CPB compared to pre-CPB phase. Sixty point three percent of patients with VSD repair and 77.8% of patients with CAVC repair showed a PaO2/FIO2 (P/F) ratio of <300 after CPB. Post- CPB P/F ratios of 120 for VSD patients and 100 for CAVC patients were considered as optimal cutoff values to highly predict prolonged (>24 hours) postoperative mechanical ventilatory support. A higher volume of transfused platelets also was associated with postoperative ventilatory support ≥24 hours in patients undergoing VSD repair, CAVC repair, and BDG shunt surgery. There was a high incidence of lung injury after CPB in neonates and infants, even in surgeries amendable for early recovery. Given that CPB-related factors (CPB duration, crossclamp time) and volume of transfused platelet were significantly associated with prolonged postoperative ventilatory support, the underlying cause of cardiac surgery-related lung injury can be multi-factorial.

Dynamic Annular Modeling of the Unrepaired Complete Atrioventricular Canal Annulus

Repair of complete atrioventricular canal (CAVC) is often complicated by atrioventricular valve regurgitation, particularly of the left-sided valve. Understanding the 3-dimensional (3D) structure of the atrioventricular canal annulus before repair may help to inform optimized repair. However, the 3D shape and movement of the CAVC annulus has been neither quantified nor rigorously compared with a normal mitral valve annulus. The complete annuli of 43 patients with CAVC were modeled in 4 cardiac phases using transthoracic 3D echocardiograms and custom code. The annular structure was compared with the annuli of 20 normal pediatric mitral valves using 3D metrics and statistical shape analysis (Procrustes analysis). The unrepaired CAVC annulus varied in shape significantly throughout the cardiac cycle. Procrustes analysis visually demonstrated that the average normalized CAVC annular shape is more planar than the normal mitral annulus. Quantitatively, the annular height-to-valve width ratio of the native left CAVC atrioventricular valve was significantly lower than that of a normal mitral valve in all systolic phases (P<.001). The left half of the CAVC annulus is more planar than that of a normal mitral valve with an annular height-to-valve width ratio similar to dysfunctional mitral valves. Given the known importance of annular shape to mitral valve function, further exploration of the association of 3D structure to valve function in CAVC is warranted.

Staged repair of transposition of the great arteries with anomalous coronary anatomy and complete atrioventricular canal.

The association of complete atrioventricular canal with transposition of the great arteries is rare, with a prevalence of less than 3-5%. We present an 18-month-old patient with a complete atrioventricular canal, side-by-side transposition of the great arteries, and anomalous coronary anatomy, managed initially with pulmonary banding and then by arterial switch with complete atrioventricular canal repair at early infancy.

Complete atrioventricular canal repair with a decellularized porcine small intestinal submucosa patch.

Congenital heart defects affect nearly 1% of all children born per year in the United States, and complete atrioventricular canal (CAVC) accounts for 2%-9%. While several patch materials have been used for septal defect closure during CAVC repair, clear superiority of one material over another has yet to be established. A retrospective review of clinical outcomes following CAVC repair at Morgan Stanley Children's Hospital/Columbia University was performed on operations conducted from March 2010 to September 2017. Univariate and Kaplan-Meir survival analyses were utilized to evaluate primary outcomes of interest following CAVC repair in the modern surgical era. A total of 73 patients were analyzed, with an average operative age of 22weeks. The majority (71%) of the patients underwent a 2-patch repair. A CorMatrix patch was used for ventricular septal defect(VSD) closure in 77% of the patients, and/or in 75% of atrial septal defect closures. There was one in-hospital mortality (1.4%) due to respiratory failure. One patient required a pacemaker. At mid-term follow-up (1.6years), a total of 7 patients required 8 reoperations due to cardiac-related indications, including 5 for left atrioventricular valve (LAVV) repair, 1 for LAVV replacement, and 2 isolated residual VSDs. A standardized repair for CAVC results in excellent outcomes in the current era, with low rates of reoperations. CorMatrix for the closure of CAVC has proven to produce good results with equivalent outcomes to other patch materials. Its ease of use and pliability make it an attractive alternative for consideration.

Bloodless Heart Surgery for an 11-kg Infant of the Jehovah’s Witness Faith Undergoing Second Repair for Complete Atrioventricular Canal

Bloodless pediatric cardiac surgery is the intent of most surgical centers especially in the Jehovah’s Witness population where it is a desire not to administer blood products because of religious belief. It is a tremendous feat, considering that most pediatric cardiovascular prime volumes are more than 20% of the patient’s estimated blood volume (EBV). We report on our bloodless strategy for a 2-year old Jehovah’s Witness with trisomy 21 and complete atrioventricular canal repair, who underwent atrial septal defect and ventricular septal defect patch closure, pulmonary artery debanding, and pulmonary arterioplasty. We modified our circuit to reduce our prime volume to approximately 10% of the EBV and removed 200 mL of the patient’s blood before surgery as acute normovolemic hemodilution. We did not alter our institutional standards for transfusion of blood and blood products. The post cardiopulmonary bypass (CPB) hematocrit was 30%. We conclude that bloodless CPB surgery can be performed safely in Jehovah’s Witness patients with a carefully planned interdisciplinary approach.

Invited Commentary

Invited Commentary

Retrospective study of complete atrioventricular canal defects: Anesthetic and perioperative challenges.

Objective:The objective of this study was to highlight anesthetic and perioperative management and the outcomes of infants with complete atrioventricular (AV) canal defects.Design:This retrospective descriptive study included children who underwent staged and primary biventricular repair for complete AV canal defects from 1999 to 2013.Setting:A single-center study at a university affiliated heart center.Participants:One hundred and fifty-seven patients with a mean age at surgery of 125 ± 56.9 days were included in the study. About 63.6% of them were diagnosed as Down syndrome. Mean body weight at surgery was 5.6 ± 6.3 kg.Methods:Primary and staged biventricular repair of complete AV canal defects. Measurements and main results: A predefined protocol including timing of surgery, management of induction and maintenance of anesthesia, cardiopulmonary bypass, and perioperative intensive care treatment was used throughout the study. Demographic data as well as intraoperative and perioperative Intensive Care Unit (ICU) data, such as length of stay in ICU, total duration of ventilation including reintubations, and total length of stay in hospital and in hospital mortality, were collected from the clinical information system. Pulmonary hypertension was noted in 60% of patients from which 30% needed nitric oxide therapy. Nearly 2.5% of patients needed permanent pacemaker implantation. Thorax was closed secondarily in 7% of patients. In 3.8% of patients, reoperations due to residual defects were undertaken. Duration of hospital stay was 14.5 ± 4.7 days. The in-hospital mortality was 0%.Conclusion:Protocolized perioperative management leads to excellent outcome in AV canal defect repair surgery.

Cardiac Function After Tetralogy of Fallot/Complete Atrioventricular Canal Repair.

Repair of complete atrioventricular canal (CAVC) with tetralogy of Fallot (TOF) is a challenging operation increasingly being performed as a complete, primary repair in infancy. Previous studies have focused on perioperative outcomes; however, midterm valve function, ventricular function, and residual obstruction have received little attention. We retrospectively reviewed 20 patients who underwent CAVC/TOF repair (January 2005 to December 2014). A two-patch repair was used in all patients to correct the CAVC defect. Tetralogy of Fallot repair included transannular patch in 11 (65%) patients and valve-sparing in 6 (35%) patients. The average age at surgery was 72 ± 122 weeks, 40% were male, and 80% had trisomy 21. Mean echo follow-up was 3.0 ± 3.0 years. There were no in-hospital or late mortalities. The rate of reoperation was 20%. At the latest follow-up, moderate left atrioventricular valve regurgitation was present in three (15%) patients and mild stenosis present in seven (35%) patients. One (5%) patient had moderate right ventricular outflow tract (RVOT) obstruction. The valve-sparing population was smaller at the time of surgery than the non-valve-sparing cohort (body surface area: 0.28 ± 0.04 vs 0.42 ± 0.11, P = .002) and less likely to have had a previous shunt (0% vs 64%, P = .01). Among the valve-sparing patients (six), at the latest follow-up, moderate pulmonary insufficiency was present in two (33%) patients. Repair of CAVC concomitant with TOF can be performed with low mortality and acceptable perioperative morbidity. Management of the RVOT remains a challenge for the long term.

Early Complete Atrioventricular Canal Repair Yields Outcomes Equivalent to Late Repair

Repair of complete atrioventricular canal early in infancy has traditionally carried greater morbidity and mortality than repair performed later. However, an individualized anatomy-based repair may give young infants outcomes that are equivalent to older patients. We retrospectively reviewed 139 patients who underwent complete atrioventricular canal repair from January 2005 to December 2012. An individualized approach was used: 2-patch repair was performed in 98 patients for large ventricular septal defects and a modified single-patch ("Australian technique") was used in 41 for "shallow" ventricular septal defects. The average age was 25.5 ± 3.9 weeks, 50% were boys, and 78% had trisomy 21. Mean follow-up was 5.1 ± 0.2 years, with 100% completeness of data. There were 3 in-hospital deaths (2.1%) and 1 late death (0.7%). A permanent pacemaker was required in 2 patients (1.4%). The rate for left atrioventricular valve reoperation was 8% at a mean of 211 ± 238 days after the original repair (range, 6 to 682 days). Compared with patients aged older than 3 months, the 39 patients (28%) who were younger than 3 months had similar perioperative courses and rate of reoperation. Compared with patients with an Australian repair, the 98 patients (71%) with a 2-patch repair were more likely to have trisomy 21 and had slightly increased cardiopulmonary bypass and cross-clamp times but similar outcomes. Multivariate analysis showed postoperative left atrioventricular valve regurgitation greater than 2 and left ventricular outflow tract obstruction were significant risk factors for reoperation on the left atrioventricular valve (both p < 0.05). Repair of complete atrioventricular canal using an individualized surgical approach yields reoperation and early mortality rates similar for younger infants compared with older infants, obviating the need to delay operation in symptomatic patients.

A Prospective Randomised Study of Postoperative Prophylactic Application of Sildenafil After Pediatric Cardiac Surgery

Postoperative aggravation of pulmonary hypertension after pediatric cardiac surgery due to temporary endothelial dysfunction may lead to sudden pulmonary arterial pressure rise with compromise of right ventricular function. Though treatment with inhaled nitric oxid (NO) has been successful, rebound pulmonary hypertension has been observed after NO withdrawal due to supression of endogenous NO sythase. Sildenafil has been shown to prevent this reaction and is widely used after pediatric cardiac surgery. The aim of our study was to evaluate the effectively of postoperative administration of oral sildenafil (1 mg/kg/day) in preventing postoperative pulmonary hypertensive crises. 21 patients after repair of complete atrioventricular canal (n=10) or ventricular septal defect (n=11) were randomly assigned to the study group or control group. The study group received sildenafil after surgery via nasogastric tube every eight hours for 48 hours, the control group received placebo. The primary outcome parameter was the number of pulmonary hypertensive events (spontaneous pulmonary arterial pressure rise to or above systemic arterial pressure). Secondary outcome parameters were: need for inotropic drugs, fluid balance, urinary output, days on the ventilator or in the intensive care unit (ICU). There was no difference in the number of pulmonary hypertensive events between both groups: median (IQR); 2 (0-6,5) sildenafil, 1 (0-2) placebo, p=0,67. Neither inotrope score, time on the ventilator, ICU length of stay, nor fluid balance differed significantly. Urinary output was significantly lower in the sildenafil group.

Dexmedetomidine utilisation and outcomes of children with trisomy 21 undergoing congenital heart disease surgery.

The diagnosis of trisomy 21 in children has been associated with failed extubation after CHD surgery. Dexmedetomidine may be a useful agent to improve postoperative outcomes in these patients, such as ventilator time, ICU length of stay, or hospital length of stay. The Pediatric Health Information System database was queried from January, 2008 to December, 2010 for patients with trisomy 21 who underwent CHD surgery. Patients who received dexmedetomidine were matched to patients who did not by propensity score. The primary outcome was ventilator days charged, and secondary outcomes included ICU and hospital length of stay. A total of 1088 patients (544 matched pairs) met inclusion criteria. Patient characteristics were similar, with the exception of more patients in the dexmedetomidine group undergoing repair of complete atrioventricular canal and fewer undergoing mechanical valve replacement (p<0.01). More patients in the dexmedetomidine group were administered milrinone, epinephrine, vasopressin, benzodiazepines, opiates, and adjunct pain and sedative medications (p<0.01). The dexmedetomidine group had greater time on the ventilator [7 (4.5-11) versus 6 (4-10) days (median, interquartile range) p<0.01] and similar ICU length of stay, hospital length of stay, and mortality compared with controls. Mixed-effects modelling clustered on institution did not show beneficial effect of dexmedetomidine on ventilator time, ICU stay, or hospital length of stay. The use of dexmedetomidine was not associated with the decreased ventilatory time. Routine use of dexmedetomidine is not warranted in this patient population.

Successful Treatment of Severe Mechanical Mitral Valve Thrombosis With Tissue Plasminogen Activator in a 7-Month-Old Infant

Severe thrombosis of a mechanical valve is a rare complication in pediatric patients. Thrombolytic therapy as treatment of mechanical mitral valve thrombosis has rarely been reported in young infants. We report the successful treatment with recombinant tissue-type plasminogen activator of a mechanical mitral valve thrombus in a 7 month-old patient with trisomy 21, complete atrioventricular canal defect and pulmonary hypertension status post complete atrioventricular canal repair and subsequent prosthetic mitral valve replacement. He presented with respiratory decompensation and shock secondary to severe mechanical mitral valve stenosis. Serial echocardiograms showed significant resolution of the thrombus within 18 h of infusion with no major bleeding complications during the treatment course. Although a rare complication of mechanical valve placement in pediatrics, thrombosis of mechanical valves may result in severe hemodynamic and respiratory compromise. This case demonstrates that thrombolytic therapy is a feasible option for the treatment of critical thrombosis in pediatric patients after MVR.

Changes in left atrioventricular valve geometry after surgical repair of complete atrioventricular canal

The most common reason for late surgical reintervention after repair of complete atrioventricular canal defects is the development of left atrioventricular valve regurgitation. We sought to determine the changes in left atrioventricular valve geometry after surgical repair that may predispose to regurgitation. Atrioventricular valve measurements were obtained by 2-dimensional echocardiography at 3 different time points (preoperative, early postoperative, and midterm postoperative [6-12 months]). Left atrioventricular valve annulus area and left ventricular volume were calculated; vena contracta of the regurgitant jet orifice was measured. All measurements were normalized relative to an appropriate power of body surface area. From January 2000 to January 2008, 101 patients with complete atrioventricular canal repair were included. Left atrioventricular valve annulus was noted to remodel from an elliptical shape to a circular shape after surgery. Left atrioventricular valve annulus area increased early postoperatively (systole: 4.1 ± 0.2 cm(2)/m(2) vs 6.1 ± 0.3 cm(2)/m(2), P < .001; diastole: 7.2 ± 0.4 cm(2)/m(2) vs 10.0 ± 0.5 cm(2)/m(2), P < .001, pre- vs postoperative, respectively). This increase was sustained in the midterm postoperative period (systole: 6.1 ± 0.3 cm(2)/m(2), P = .85, vs diastole: 10.0 ± 0.4 cm(2)/m(2), P = .78, early vs midterm postoperative). Left ventricular volume increased in the early and midterm postoperative periods compared with preoperative (systole: 16.9 ± 1.2 mL/m(2) vs 26.2 ± 1.7 mL/m(2), P < .001; diastole: 35.0 ± 2.4 mL/m(2) vs 52.5 ± 3.2 mL/m(2), P < .001). Complete atrioventricular canal repair leads to left atrioventricular valve annular shape change with increased area and circular shape. The change in left atrioventricular valve annulus shape appeared to be mainly due to increased circumference in the posterior free wall of the annulus. These findings may provide a mechanism for the progression of central regurgitation seen after complete atrioventricular canal repair and a potential solution.