Development of a Resilience Parameter for 3D-Printable Shape Memory Polymer Blends

The goal of this paper was to establish a metric, which we refer to as the resilience parameter, to evaluate the ability of a material to retain tensile strength after damage recovery for shape memory polymer (SMP) systems. In this work, three SMP blends created for the additive manufacturing process of fused filament fabrication (FFF) were characterized. The three polymer systems examined in this study were 50/50 by weight binary blends of the following constituents: (1) polylactic acid (PLA) and maleated styrene-ethylene-butylene-styrene (SEBS-g-MA); (2) acrylonitrile butadiene styrene (ABS) and SEBS-g-MA); and (3) PLA and thermoplastic polyurethane (TPU). The blends were melt compounded and specimens were fabricated by way of FFF and injection molding (IM). The effect of shape memory recovery from varying amounts of initial tensile deformation on the mechanical properties of each blend, in both additively manufactured and injection molded forms, was characterized in terms of the change in tensile strength vs. the amount of deformation the specimens recovered from. The findings of this research indicated a sensitivity to manufacturing method for the PLA/TPU blend, which showed an increase in strength with increasing deformation recovery for the injection molded samples, which indicates this blend had excellent resilience. The ABS/SEBS blend showed no change in strength with the amount of deformation recovery, indicating that this blend had good resilience. The PLA/SEBS showed a decrease in strength with an increasing amount of initial deformation, indicating that this blend had poor resilience. The premise behind the development of this parameter is to promote and aid the notion that increased use of shape memory and self-healing polymers could be a strategy for mitigating plastic waste in the environment.

Development and Characterization of Furfuryl-Gelatin Electrospun Scaffolds for Cardiac Tissue Engineering

In this study, three types of electrospun scaffolds, including furfuryl-gelatin (f-gelatin) alone, f-gelatin with polycaprolactone (PCL) in a 1:1 ratio, and coaxial scaffolds with PCL (core) and f-gelatin (sheath), were developed for tissue engineering applications. Scaffolds were developed through single nozzle electrospinning and coaxial electrospinning, respectively, to serve as scaffolds for cardiac tissue engineering. Uniform fibrous structures were revealed in the scaffolds with significantly varying average fiber diameters of 760 ± 80 nm (f-gelatin), 420 ± 110 nm [f-gelatin and PCL (1:1)], and 810 ± 60 nm (coaxial f-gelatin > PCL) via scanning electron microscopy. The distinction between the core and the sheath of the fibers of the coaxial f-gelatin > PCL electrospun fibrous scaffolds was revealed by transmission electron microscopy. Thermal analysis and Fourier transformed infrared (FTIR) spectroscopy revealed no interactions between the polymers in the blended electrospun scaffolds. The varied blending methods led to significant differences in the elastic moduli of the electrospun scaffolds with the coaxial f-gelatin > PCL revealing the highest elastic modulus of all scaffolds (164 ± 3.85 kPa). All scaffolds exhibited excellent biocompatibility by supporting the adhesion and proliferation of human AC16 cardiomyocytes cells. The biocompatibility of the coaxial f-gelatin > PCL scaffolds with superior elastic modulus was assessed further through adhesion and functionality of human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes, thereby demonstrating the potential of the coaxially spun scaffolds as an ideal platform for developing cardiac tissue-on-a-chip models. Our results demonstrate a facile approach to produce visible light cross-linkable, hybrid, biodegradable nanofibrous scaffold biomaterials, which can serve as platforms for cardiac tissue engineered models.

Design of Shape Memory Thermoplastic Material Systems for FDM-Type Additive Manufacturing

The work presented here describes a paradigm for the design of materials for additive manufacturing platforms based on taking advantage of unique physical properties imparted upon the material by the fabrication process. We sought to further investigate past work with binary shape memory polymer blends, which indicated that phase texturization caused by the fused filament fabrication (FFF) process enhanced shape memory properties. In this work, two multi-constituent shape memory polymer systems were developed where the miscibility parameter was the guide in material selection. A comparison with injection molded specimens was also carried out to further investigate the ability of the FFF process to enable enhanced shape memory characteristics as compared to other manufacturing methods. It was found that blend combinations with more closely matching miscibility parameters were more apt at yielding reliable shape memory polymer systems. However, when miscibility parameters differed, a pathway towards the creation of shape memory polymer systems capable of maintaining more than one temporary shape at a time was potentially realized. Additional aspects related to impact modifying of rigid thermoplastics as well as thermomechanical processing on induced crystallinity are also explored. Overall, this work serves as another example in the advancement of additive manufacturing via materials development.

Added Value of Live 3-Dimensional Transesophageal Echocardiography During Procedures in Fontan Patients

3D transesophageal echocardiography (3D-TEE) has proven useful and accurate during some operating room (OR), interventional cardiac catheterization (Cath), and electrophysiologic (EP) procedures. The use of 3D-TEE during similar procedures in patients who have undergone Fontan surgery and its additional value have not been previously reported. To determine if live 3D-TEE during procedures post Fontan has added value, 3D-TEEs in 58 post-Fontan patients over a 5-year study period were reviewed. Additional information provided by 3D-TEE (over 2D-TEE) was classified into the following: A: new information which changed/refined the plan and 0: no new important information. Pre- and post-bypass OR 3D-TEEs were counted as one study. A total of 67 3D-TEEs (41 Cath, 13 OR, and 13 EP procedures) were performed. Median age was 14 years (6-39 years). Median weight was 47 kg (21-109 kg). In Cath procedures, only 2/41 (5%) were graded A (R to L atrial level shunt [Fontan leak], n = 1; thrombus in pulmonary artery stump, n = 1). In the OR, 6/13 (46%) were graded A (atrioventricular valvuloplasty, n = 1; neo-aortic valvuloplasty, n = 1; relief of systemic and pulmonary venous outflow obstruction, n = 2 and n = 2; respectively). In EP procedures, 4/13 (31%) were graded A (thrombus, n = 3; mapping for lead placement to assist in multisite pacing for dyssynchrony, n = 1). 3D-TEE of Fontan improved visualization and frequently added value in the OR/EP lab and may be helpful in select catheterization cases. Future studies with a larger sample could build on this data to identify when 3D-TEE will be most useful.

Comparison of Semi-Automated Versus Manual Quantitative Right Ventricular Assessment in Hypoplastic Left Heart Syndrome

Quantitative echocardiographic evaluation is important for systemic right ventricles, but its asymmetric shape makes this challenging and time consuming when performed manually. Semi-automated software could make these quantitative measures easier to accomplish in the clinical setting. We hypothesized that semi-automated software would approximate manual measures of right ventricular size and function. Children with hypoplastic left heart who had echocardiograms were prospectively identified. These measurements were performed using manual and semi-automated techniques: end-diastolic and end-systolic area, fractional area change (FAC), dimensions (longitudinal, basal and mid-cavitary diameters), and tricuspid annular plane systolic excursion (TAPSE). Agreement between measures was evaluated. Sixty-three echocardiograms were analyzed. Intra- and inter-observer reliability was acceptable and similar between methods except that inter-observer reliability for the manual method was superior for TAPSE. Correlation between methods was high (r > 0.9, p < 0.001) for most of the measures. Correlation for FAC was r = 0.79, and for TAPSE the correlation was r = 0.61 (both p < 0.001). The percent relative difference between manual and semi-automated methods was less than 6% for most measures. End-systolic area and FAC had a relative difference of 10% and 11% respectively. The only measure with substantial bias between the manual and semi-automated methods was TAPSE which had a relative difference of 52%. EchoInsight® semi-automated software provides similar measures of right ventricular dimensions and FAC in patients with hypoplastic left heart compared to manual measures. Measures of TAPSE do not correlate well between manual and semi-automated methods. Further research is warranted on the use of semi-automated analyses in this patient population.

Saline Contrast Transesophageal Echocardiography in Fontan Patients: Assessment of the Presence, Type, and Size of Right to Left Shunts

Right to left (R-L) shunts resulting in cyanosis or systemic embolization occur after the Fontan procedure. The primary modality of diagnosing these is angiography. Successful delineation of these shunts in Fontan patients using selective saline contrast transesophageal echocardiography (SCTEE) may allow for reduced radiation and contrast exposure. We hypothesized that SCTEE could accurately determine the presence, type, and semiquantitative shunt size of R-L shunts in Fontan patients. SCTEE was performed in Fontan patients undergoing angiography for clinical indications. Injections were performed in six sites: mid-Fontan, right and left pulmonary arteries, superior and inferior vena cavae, and innominate vein. R-L shunt size was subjectively graded as 0 = absent, 1 = small, and 2 = medium or large based on echo contrast density in the left atrium. SCTEE was compared to angiography. 33 patients with Fontan were studied with median age 15 years, median weight 50.1 kg, and median O₂ saturation of 90% in the R-L shunt group and 95% in the no R-L shunt group. R-L shunt types included intracardiac shunts (ICS), veno-venous collaterals (VVCs), arteriovenous malformations (AVMs), and their combinations. SCTEE versus angiography results were the same for the presence, type, and size of R-L shunts in 79% (26/33). SCTEE identified shunts in 88% (29/33). Angiography identified shunts in 85% (28/33). Neither method missed any medium or large R-L shunts. SCTEE and angiography had similar accuracy. SCTEE accurately detected the presence, type, and size of R-L shunts in most Fontan patients in this study. This can be used to guide targeted angiography, reducing radiation exposure and contrast load.

Three-dimensional analysis of regional right ventricular shape and function in repaired tetralogy of Fallot using cardiovascular magnetic resonance

BACKGROUND

Patients with surgically repaired tetralogy of Fallot (rTOF) often have residual pulmonic valve regurgitation, leading to abnormal remodeling and dysfunction of the right ventricle often requiring pulmonic valve replacement. We tested the hypothesis that 3D analysis of right ventricular (RV) shape and function may reveal differences in regional adaptive remodeling that occurs in patients with rTOF, depending on whether a transannular patch (TAP) was utilized.

METHODS

Forty patients with rTOF who underwent cardiac magnetic resonance imaging (1.5 T), including 20 with and 20 without TAP, and 10 normal controls were studied. Images were analyzed to measure RV endocardial curvature and global and regional volume and function.

RESULTS

RV ejection fraction (EF) was 42 ± 11% in TAP and 38 ± 9% in no-TAP (p = 0.19), both lower than 54 ± 3% in controls (p < 0.01). Left ventricular (LV) EF was 54 ± 9% in TAP, 54 ± 8% in no-TAP (p = 0.87) and 61 ± 16% in controls (both p < 0.01). Indexed LV end-diastolic volumes were higher in no-TAP than in TAP subgroup (p = 0.02). With TAP, mid RV septum showed lower curvature during diastole (less convex), than the mid and apical free walls and free wall adjacent to the RV outflow tract (RVOT; more convex). There were no differences in curvature during systole between rTOF subgroups but mid and RVOT free walls showed higher curvature versus controls.

CONCLUSIONS

This is the first study to comprehensively describe the influence of TAP on changes in regional RV shape in patients with rTOF. Understanding these differences may help guide therapeutic options for residual pulmonary valve regurgitation in rTOF patients.

Tissue Motion Annular Displacement Predicts Mortality/Transplant After the Bidirectional Glenn

Background:

Quantifying right ventricular function in patients with a systemic right ventricle (RV) is difficult but important for prognosis. Tissue motion annular displacement tracks displacement of the tricuspid annulus toward the apex. We evaluated this measure alongside fractional area change (FAC) on patients with single, RV prior to the bidirectional Glenn procedure. We tested both measures for correlation with outcomes.

Methods:

Retrospective measurement of tissue motion annular displacement and FAC was performed on echocardiographic clips obtained prior to the bidirectional Glenn. A chart review included postoperative outcomes and midterm mortality/transplant. Bivariate correlations and Cox proportional hazards models were used for analyses.

Results:

Fifty-one patients with dominant RV underwent the bidirectional Glenn procedure and all had image quality that allowed analysis. The age ranged from 3 to 11 months (median 4 months). Neither tissue motion annular displacement nor FAC correlated with short-term postoperative outcomes. Tissue motion annular displacement was independently predictive of mortality/transplant ( P = .03) in the Cox hazard model. The mean for survivors was 12.4% and for nonsurvivors/transplants was 10.0%. Tissue motion annular displacement intra-observer variability was 2.8% (1.2%-3.5%). Interobserver mean variability was 6.1% (3.3%-8.1%). Fractional area change was not predictive of mortality/transplant.

Conclusion:

Tissue motion annular displacement is an independent predictor of midterm mortality/transplant after the bidirectional Glenn procedure in patients with single, RV, in this study. It may outperform FAC in this regard and has good reproducibility. Tissue motion annular displacement may be a useful measure in identifying high-risk children in this population.

Right Ventricular Longitudinal Shortening Before and After Stage I Surgical Palliation Correlates with Outcomes

Quantification of right ventricular function is difficult, but important, in patients with single ventricles. Tissue motion annular displacement (TMAD) is an echocardiographic tool that measures displacement of the tricuspid valve relative to the apex. We evaluated TMAD, lateral annular displacement (LAD), and fractional area change (FAC) for correlation with outcomes. We measured TMAD, LAD, FAC, and other variables that may affect prognosis in patients with single right ventricle physiology pre- and post-Stage I palliation and correlated them with outcomes up to the Glenn procedure. Intra- and inter-observer variability for TMAD measurements were 2.7% (1.2-3.5%) and 6.1% (3.3-8.1%), respectively. Sixty-six subjects met the inclusion criteria. Pre-Stage I TMAD was 13.7% (SD 3.9%). TMAD had a linear relationship with FAC (r2 = 0.76). There was a correlation between TMAD and hospital stay (p = 0.044) and ECMO/arrest (p = 0.024). LAD correlated with ECMO/arrest (p = 0.045) and mortality/transplant (p = 0.049). FAC correlated with in-hospital mortality (p = 0.028). Post-Stage I TMAD was 11.8% (SD 3.7%). TMAD, LAD, and FAC all correlated with in-hospital mortality and mortality/transplant. In multivariate models, TMAD was independently predictive of weight for age Z score pre-Glenn. TMAD, FAC, and LAD correlate with clinically significant outcomes after the first-stage palliation. TMAD correlated with more outcomes than FAC and was the only measure that was independently predictive of any outcome. TMAD is a reproducible measure of RV function in this population. TMAD has prognostic value before and after first-stage palliation and may outperform more traditional measures.

Three-Dimensional Echocardiographic En Face Views of Ventricular Septal Defects: Feasibility, Accuracy, Imaging Protocols and Reference Image Collection

BACKGROUND

Ventricular septal defect (VSD) is the most common congenital cardiac anomaly. Accurate assessment is critical for planning treatment. Recent advances in three-dimensional (3D) echocardiography have improved image quality and ease of use.

METHODS

The feasibility and accuracy of three specific 3D echocardiographic protocols to demonstrate en face views of VSDs were analyzed in a retrospective review of 100 consecutive patients. Sixty-four patients underwent transthoracic echocardiography and 36 transesophageal echocardiography. Types of VSDs included 34 muscular, 32 perimembranous, 18 malaligned, 11 inlet, four outlet, and one acquired. Ages ranged from 1 day to 77 years, and body weights from 3 to 92 kg. Three-dimensional echocardiographic full-volume mode with standard XYZ and adjustable plane cropping, 3D full-volume mode with iCrop, and narrow-sector live 3D protocols were compared for feasibility and accuracy to obtain a diagnostic-quality en face view of a VSD.

RESULTS

The success rate for obtaining a high-quality en face image for the three protocols was 100% for full-volume mode with iCrop, 97% for full-volume standard mode, and 94% for narrow-sector live 3D mode. The ability of both full-volume mode with iCrop and full-volume standard mode to demonstrate a VSD was slightly better than that of narrow-sector live 3D mode (P < .001 for both vs narrow-sector live 3D mode). In all patients, the type, size, and location of the VSD were demonstrated accurately by two or more of the protocols.

CONCLUSIONS

Three-dimensional echocardiography of VSDs is feasible and accurate in most patients using defined protocols. The protocols are described and illustrated in detail, and a reference 3D image collection is presented.

Transesophageal echocardiography of intracardiac thrombus in congenital heart disease and atrial flutter: the importance of thorough examination of the Fontan

Transesophageal echocardiography (TEE) is used in atrial flutter or fibrillation (AFF) before electric cardioversion to detect intracardiac thrombi. Previous studies have described the use of TEE to diagnose intracardiac thrombi in the left atrium and left atrial appendage, which has an incidence of 8 % among patients without congenital heart disease (CHD). In their practice the authors have noted a significant incidence of intracardiac thrombi in other structures of patients with CHD and AFF. This study aimed to determine the incidence and location of intracardiac thrombi using TEE in patients with CHD requiring electric cardioversion of AFF and to compare the use of TEE and transthoracic echo (TTE) to detect intracardiac thrombus in this population. A retrospective chart review of TEE and TTE findings for all patients with CHD who had electric cardioversion of AFF at our institution from 2005 to 2013 was conducted. The diagnosis, presence, and location of intracardiac thrombus were determined. The TEE and TTE results were compared. The study identified 27 patients with CHD who met the study entry criteria at our institution between 2005 and 2013. Seven of these patients had a single ventricle with Fontan palliation. All the patients presented with AFF and had TEE before electric cardioversion. No patients were excluded from the study. The patients ranged in age from 2 to 72 years (median, 21 years) and weighed 17-100 kg (median, 65 kg). The duration of AFF before TEE and attempted cardioversion ranged from 1 day to 3 weeks (median, 3.5 days). Intracardiac thrombus was present in 18 % (5/27) of the patients and in 57 % (4/7) of the Fontan patients with AFF. No embolic events were reported acutely or during a 6-month follow-up period. Among patients with CHD who present with AFF, a particularly high incidence of intracardiac thrombi is present in the Fontan patients that may be difficult to detect by TTE. Thorough TEE examination of the Fontan and related structures is indicated before electric cardioversion of AFF. The incidence of intracardiac thrombus in CHD patients is more than double that reported in non-CHD patients.

Significance of low peak Doppler velocity in the proximal sano conduit in hypoplastic left heart syndrome

BACKGROUND

The Sano modification of the Norwood operation is a well-established first step palliation for hypoplastic left heart syndrome (HLHS). Theoretically, the first point of resistance to pulmonary flow should be in the proximal Sano, generating high Doppler flow velocity. Paradoxically, however, some patients have low gradients in the proximal Sano conduit. The objective of this study was to determine the hemodynamic and anatomic significance of low proximal Sano Doppler flow velocity and its clinical implications.

METHODS

Doppler-derived peak gradients in the proximal Sano conduits were measured in HLHS patients after Norwood-Sano surgery over a 4-year period and confirmed by cardiac catheterization within 2 to 4 weeks. Clinical outcomes of patients with proximal Sano gradients of 30 mm Hg or less (group 1) were compared with patients whose gradient was greater than 30 mm Hg (group 2).

RESULTS

Of the 53 patients, 21 (40%) belonged to group 1. Patients in group 1 had smaller ostial right and left pulmonary artery (PA) diameter (3.2 ± 1.2 mm versus 4.5 ± 1.8 mm, p = 0.03; and 3.4 ± 1.2 mm versus 5.6 ± 2.1 mm, p = 0.01) when compared with patients in group 2. Patients (7 of 10) who needed either balloon angioplasty of a distal Sano or proximal branch PA were from group 1 (p = 0.01). Patients in group 1 had higher rates of unintended PA interventions (33% versus 9%) and complications (48% versus 16%) compared with group 2.

CONCLUSIONS

Low peak Doppler flow velocity in the proximal Sano correlates with the presence of either distal Sano stenosis or proximal branch PA stenosis. These patients require close follow-up in the interstage period and may need earlier intervention.

Three-dimensional transesophageal echocardiography of atrial septal defect device closure

Most secundum atrial septal defects (ASD) are amenable to device closure. Three- dimensional transesophageal echocardiography (3DTEE) can be used to obtain an en face view of the ASD and important surrounding structures which provides for analysis of the type, size, shape, orientation, number and position of orifices, ASD rims and important surrounding structures in a single live 3D echo view. Also, 3DTEE is ideal for monitoring the position and configuration of devices and delivery hardware using live real -time imaging techniques. In this chapter we will describe and illustrate the methods to obtain and optimize 3DTEE en face views of the ASD during device closure using 3D zoom, live 3D and 3D full volume plus iCrop modalities. The respective 3D TEE modalities, imaging protocols, advantages and limitations will be discussed. Because it is useful, accurate and fairly simple to use, we have adopted 3D TEE for routine clinical use during ASD device closure.

Transesophageal echocardiography in critically ill acute postoperative infants: comparison of AcuNav intracardiac echocardiographic and microTEE miniaturized transducers

BACKGROUND

Multiple barriers to transthoracic echocardiography are present in critically ill infants immediately after surgery. Transesophageal echocardiography (TEE) is sometimes needed to obtain specific important information that transthoracic echocardiography fails to demonstrate. Formerly, the investigators used the AcuNav intracardiac echocardiographic (ICE) intravascular ultrasound transducer (8 Fr, 2.5 mm, 64-element crystal array, multifrequency [5.5-10 MHz], single longitudinal plane, linear phased array [Siemens Medical Solutions USA, Inc., Mountain View, CA]). Recently, the investigators have also used the microTEE transducer (8-mm transducer tip, 5.2-mm shaft, multifrequency [3-8 MHz], multiplane phased array, 32-element probe [Philips Medical Systems, Andover, MA]). Both transducers have two-dimensional, M-mode, color Doppler, and pulsed-wave and continuous-wave Doppler capabilities. The aim of this study was to compare the efficacy, safety, ease of insertion, capabilities, utilization, and cost of the AcuNav ICE transducer versus those of the microTEE transducer.

METHODS

A retrospective review of all 50 postoperative critically ill infants who underwent TEE using the AcuNav and microTEE in the past 5 years was conducted. TEE was performed as ordered by the attending physician to answer a specific question not answered by transthoracic echocardiography.

RESULTS

In all cases, the clinical information sought was obtained. The AcuNav ICE transducer was safe, easy to insert through the transnasal route, and did not require paralysis; however, it had a limited number of echocardiographic views and had greater sterilization cost. The microTEE transducer had greater echocardiographic capabilities and lower sterilization cost; however, it was slightly more difficult to insert, had a few manageable complications, and required more sedation and paralysis.

CONCLUSIONS

TEE in this setting has increased because of demonstrated efficacy and safety. Both the AcuNav ICE and microTEE transducers are useful and effective in this critical clinical scenario.

Hypoplastic left heart syndrome and aortic atresia-mitral stenosis variant: role of myocardial protection strategy and impact of ventriculo-coronary connections after stage I palliation

Aortic atresia-mitral stenosis (AA-MS) has been implicated as a determinant of outcome after Stage-1 palliation (S1P) in hypoplastic left heart syndrome (HLHS).Studies evaluating the association of AA-MS with ventriculo-coronary connections (VCC) and mortality report conflicting results. The significance of VCC, myocardial protection, and shunt strategy after S1P has yet to be determined. Between January 2005 and July 2009, 100 neonates with HLHS underwent S1P. Mitral and aortic valves and presence of VCC were assessed. Antegrade continuous cold blood cardioplegia was administered throughout the vast extent of the neo-aortic reconstruction. A right ventricle-to-pulmonary shunt was used for an ascending aortic diameter of 0.6 mm/kg or less. Survival analysis was performed to determine predictors and assess impact of AA-MS and VCC on hospital and interstage mortality. Twenty-seven (of 100) patients had AA-MS. The mean age and weight at S1P were 6.5 ± 2.8 days and 3.09 ± 0.47 kg, respectively. VCC were found in 56% of AA-MS. Twenty-two had Norwood-Sano, 3 had classic Norwood, and 2 had hybrid S1P. VCC were associated with AA-MS, endocardial fibroelastosis, and ascending aortic size <2 mm (P < 0.05) but not higher mortality (P = ns). Operative and interstage survival for AA-MS after S1P was 85.2 and 71%, respectively (not statistically different compared to all other subtypes; P = ns). Actuarial survival after S1P at 1, 3, 6, 12, and 36 months was 92.9 ± 4.9, 78.6 ± 7.8, 75 ± 8.2, 71.3 ± 8.3, and 71.3 ± 8.3%, respectively. Intact atrial septum and post-S1P renal dysfunction (P < 0.05) were independent predictors of hospital and interstage mortality. In patients with HLHS, AA-MS carries no survival disadvantage after S1P during the hospital and interstage period regardless of VCC. Intact atrial septum and post-S1P renal dysfunction predict early and interstage mortality. Myocardial protection and shunt strategy might influence the outcome in this HLHS variant.

Ventriculocoronary artery connections with the hypoplastic left heart: a 4-year prospective study: incidence, echocardiographic and clinical features

Ventriculocoronary connections (VCCs), also called sinusoids, occur with hypoplastic left heart (HLH). Previous reports are limited to case reports, pathologic series, and surgical series with limited detail, which may underestimate the incidence and overestimate the severity of VCCs in HLH. A study was conducted to determine the incidence VCCs in HLH, their effect on survival, and their echocardiographic and clinical features. The echocardiograms and medical records of 100 consecutive neonatal HLH cases were analyzed. All had an aortic and a mitral valve diameter and a left ventricular (LV) volume less than Z-3. For palliation, Norwood, Sano, or hybrid procedures were used, and if the patient was alive, subsequent bidirectional Glenn and extracardiac Fontan procedures were applied. Cases were classified as manifesting mitral and aortic atresia (MAAA), mitral and aortic stenosis (MSAS), or mitral stenosis and aortic atresia (MSAA). All other diagnoses or any case with additional cardiac anomalies were excluded from the study. Overall, VCCs were found in 15% of the cases. They occurred in 56% of the MSAA subtype cases and were not statistically associated with a high mortality rate. However, in one case, large and multiple VCCs definitely caused or contributed to early death. All VCCs had a transmyocardial course, a turbulent color-Doppler flow, and a dominant usually retrograde systolic coronary artery flow pattern. The VCCs were associated (p < 0.05) with MSAA, endocardial fibroelastosis, and ascending aortic size less than 2 mm. As shown by the findings, 15% of the HLH patients had MSAA with VCCs. Unless the VCCs were large or extensive, they did not contribute to mortality. Detailed echocardiographic analysis of VCCs in HLH was feasible. Recent reports emphasize more severe cases.

Anomalous left coronary artery from the right sinus of valsalva and noncompaction of the left ventricle

Anomalous origin of the left coronary artery is a well-known cause of sudden death. Noncompaction of the ventricular myocardium is a cardiomyopathy characterized by prominent trabeculae and deep intertrabecular recesses. Both anomalies are rare. We report the case of a child with both anomalous origin of the left coronary artery from the right sinus of Valsalva and noncompaction of the left ventricular myocardium found during an evaluation for Kawasaki's disease.

Double aortic arch and d-transposition of the great arteries

We present a rare case of D-transposition of the great arteries (D-TGA) and double aortic arch (DAA). The anatomy was prospectively and preoperatively diagnosed by echocardiography and confirmed by ultra-fast computed tomography. The patient underwent successful arterial switch operation and division of the vascular ring at a single procedure.

Annular and Septal Doppler Tissue Imaging in Children: Normal z-Score Tables and Effects of Age, Heart Rate, and Body Surface Area

The aim of this study was to construct normal z-score tables for longitudinal directed Doppler tissue imaging (DTI) systolic wave (S), DTI early diastolic wave (E'), and DTI late diastolic wave (A') at the mitral valve annulus (MV), superior ventricular septum (VS), and tricuspid valve annulus (TV) in pediatric patients. We analyzed normal echocardiograms from 634 children aged 1 day to 18 years, heart rate (HR) range of 50 to 194/min, and body surface area (BSA) range of 0.1 to 2.8 m2. First we determined the effects of age, HR, and BSA on the S, E', and A' at the MV, VS, and TV sampling sites by univariate analysis. Next we determined which of the 3 factors, age versus HR versus BSA, correlated best with the S, E', and A' at each of the 3 sampling sites by multivariate analysis. Finally, using the specific factor of age versus HR versus BSA that best predicted a particular DTI wave at a particular sampling site, we constructed z-score tables for each of the 3 DTI parameters at each of the 3 sampling sites. The S range was: MV = 2.2 to 23.2 cm/s; VS = 1.6 to 22.3 cm/s; and TV = 1.8 to 31.3 cm/s. By univariate analysis the S correlated negatively with HR and positively with age and BSA with strong correlations at all 3 sites. By multiple regression analysis the S correlated best with age at all 3 sites. The E' range was: MV = 2.4 to 37.1 cm/s; VS = 1.8 to 29.0 cm/s; and TV = 2.4 to 32.4 cm/s. The E' varied negatively with HR and positively with age and BSA with strong correlations by univariate analysis at all 3 sites. By multiple regression, the E' correlated best with age for the VS and TV sites, and correlated best with HR at the MV site. The E' at the MV site also strongly correlated with age by multivariate analysis. The A' range was: MV = 2.9 to 20.7 cm/s; VS = 2.7 to 18.2 cm/s; and TV = 1.1 to 29.3 cm/s. The A' had a strong positive correlation with HR at all 3 sites, a strong negative correlation with BSA and age at the TV site only, with no statistical significant correlation of the MV and VS site A' to BSA or age. Using multiple regression analysis the A' correlated best with HR at all 3 sites. Z-score tables developed from a large sample volume encompassing the entire spectrum of ages, HR, and BSA encountered in pediatric patients and developed using the strongest predicting factor serve as reference data for longitudinal directed DTI annular and septal S, E', and A' normal values in children.

Systolic and diastolic time intervals measured from Doppler tissue imaging: normal values and Z-score tables, and effects of age, heart rate, and body surface area

The aim of this study was to develop normal values, including Z-score tables when appropriate, for systolic time (St) and diastolic time (Dt) intervals measured by Doppler tissue imaging (DTI) and to determine the effects of age, heart rate (HR), and body surface area on DTI-derived time intervals in children. We studied 593 children with normal echocardiogram results. Developmental factors ranged from age 1 day to 18 years, HR 46 to 182/min, and body surface area 0.08 to 2.80 m(2). A total of 7 DTI-derived time interval parameters were studied. Five time interval parameters were measured from DTI: isovolumic contraction time (IVCT), isovolumic relaxation time (IVRT), ejection time, St, and Dt. In addition, we calculated the Tei index (TX) and St/Dt. We sampled longitudinal directed DTI waves from 3 sites: mitral annulus, basal interventricular septum, and tricuspid annulus from an apical 4-chamber view. Parameters were measured in each case from a single echocardiogram during times of hemodynamic stability. By univariate analysis all 7 time intervals at each of the 3 sampling sites correlated with age, HR, and body surface area (P < .001-P < .003), except the mitral annulus TX (P = .1). The following results are all based on multivariate analysis. IVCT, IVRT, and TX correlated best with age at all 3 sites (P < .001). However, when we corrected for HR by dividing by square root(R)-R interval, both corrected IVCT and corrected IVRT became constants at all 3 sites. The change in TX with age was very small and not clinically significant. Therefore, for practical clinical purposes, corrected IVCT, corrected IVRT, and TX were constant at all 3 sites. Ejection time, St, Dt, and St/Dt correlated best with HR at all 3 sites (P < .001). Ejection time, St, and Dt all decreased at faster HRs, whereas St/Dt increased at faster HRs.

Right Ventricular Tei Index in Children: Effect of Method, Age, Body Surface Area, and Heart Rate

The right ventricular (RV) Tei index (RVTX) has been used to analyze systolic and diastolic global RV function in various congenital and acquired cardiac abnormalities in children. We conducted a study to determine the effects of the methods of Doppler tissue imaging (DTI) versus pulse wave Doppler (PWD) and age, body surface area (BSA), and heart rate on the RVTX in a population of 308 children with normal echocardiogram findings. Participants ranged in age from 1 day to 18 years, with BSA from 0.08 to 2.4 m2 and heart rate from 46 to 182/min. The RVTX was calculated by both DTI and PWD in each patient during a single echocardiographic examination. RVTX-DTI = 0.37 +/- 0.05 (mean +/- SD) versus RVTX-PWD = 0.34 +/- 0.06 were slightly but statistically different (P < .001). Univariate linear regression analysis showed age and BSA both had small but significant positive effects on both the RVTX-DTI and RVTX-PWD, and heart rate had a small but significant negative effect on both techniques (all with P < .01). By multivariate regression analysis RVTX-DTI was significantly affected only by the BSA and the RVTX-PWD only by age (both with P < .05). Therefore, one must consider the method of RVTX measurement, the BSA for RVTX-DTI, and the age for RVTX-PWD to accurately assess RVTX values.

Unusual atrial septal anatomy resulting in an interatrial chamber: the true triatrial heart?

We report two patients who were found to have nearly identical, very peculiar atrial septal anatomy. The septum actually consisted of two distinct septa with discrete defects creating an interatrial chamber. The orifice from the left atrium was unrestrictive, but the orifice to the right atrium was restrictive. Overall, there was net left-to-right shunting. This finding represents a clinical dilemma: Left untreated, the interatrial chamber might be a nidus for thrombus formation, but attempting device closure might result in incomplete obliteration of the chamber, also resulting in potential locus for clot formation. Clot formation might lead to systemic embolization. Angiographic findings are correlated with echocardiographic findings. Embryology and treatment options are considered.

Left Ventricular Tei Index in Children: Comparison of Tissue Doppler Imaging, Pulsed Wave Doppler, and M-Mode Echocardiography Normal Values

The Tei index has been found to be useful for analyzing systolic and diastolic global ventricular function in a wide variety of congenital and acquired cardiac abnormalities. However, there are some discrepancies between reports as to the normal values for the Tei index obtained by the different echocardiographic techniques and by different investigators. We conducted a prospective study to determine the normal range of left ventricular Tei index (LVTX) values in a broad sample of children using tissue Doppler imaging, pulsed wave Doppler, and M-mode echocardiography. In all, 289 children with normal echocardiogram findings (age 1 day-18 years, body surface area 0.08-2.4 m(2), heart rate 46-182/min) were studied. The LVTX was calculated by all 3 methods in each patient during a single echocardiographic examination. The normal LVTX values (mean +/- SD) for the 3 techniques were: LVTX-Doppler tissue imaging = 0.38 +/- 0.06; LVTX-pulsed wave Doppler = 0.36 +/- 0.07; and LVTX-M-mode echocardiography = 0.29 +/- 0.08. LVTX-Doppler tissue imaging and LVTX-pulsed wave Doppler values were only slightly but statistically significantly different (P < .05). LVTX-M-mode echocardiography values were consistently and significantly less than those obtained by both of the other two methods (P < .01, respectively). The effects of age, body surface area, and heart rate were not clinically significant. These results are similar but not identical to those from prior studies.

Double Atrial Septum with Persistent Interatrial Space: Echocardiographic Features of a Rare Atrial Septal Malformation

We describe the echocardiographic features of 4 new cases of a rare atrial septal malformation consisting a double atrial septum with a midline chamber between the left and right atrium. Half of the cases had major left-sided obstructive lesions. Transthoracic, transesophageal, intracardiac, and fetal echocardiographic features of this anomaly are demonstrated. Previous descriptions, embryologic speculations, and clinical considerations are discussed.

Intermediate results of the anatomic repair for congenitally corrected transposition

BACKGROUND

Anatomic repair of congenitally corrected transposition of the great arteries has several advantages over the traditional approach but lacks long-term evaluation.

METHODS

The data on 12 patients who had the procedure between January 1989 and June 2000 were retrospectively reviewed. Associated lesions included ventricular septal defect in 12 patients, pulmonary stenosis in 10 patients, and moderate to severe tricuspid valve regurgitation in 4 patients. Mean age at operation was 9+/-3.6 months. All patients had venous switch Mustard procedure. Tunneling of the morphologic left ventricle through the ventricular septal defect to the aorta with insertion of right ventricular to pulmonary artery conduit was performed in 10 patients, and arterial switch operation in 2. Concomitant tricuspid valvuloplasty was done in 2 patients and ventricular septal defect enlargement in 1.

RESULTS

There was one hospital death (9%) in the patient who needed ventricular septal defect enlargement. Complications included atrioventricular block requiring pacemaker insertion in 1 patient (9%) and superior vena caval obstruction in 1 patient (9%). Follow-up is available on all patients 0.5 to 10 years (mean, 7.6+/-3.1 years). All patients are asymptomatic. Exercise test results on the three oldest patients were normal. Bradytachyarrhythmias developed in 4 patients (36%). Right ventricular to pulmonary artery conduit replacement was needed in 5 patients 2.2 to 7.1 years (mean 5.2+/-3.6 years) postoperatively. Mild to moderate tricuspid valve regurgitation persisted in 2 patients. Systemic left ventricular fractional shortening was 36% to 47% (mean, 39%+/-4.6%), and ejection fraction was 49% to 70% (mean, 60.8%+/-7.9%).

CONCLUSIONS

The double switch operation can be performed safely with minimal intermediate and long-term complications.

The effect on the hemodynamic stability of varying calcium chloride administration during protamine infusion in pediatric open-heart patients

IMPLICATIONS

We conducted a randomized study in 147 pediatric patients undergoing cardiopulmonary bypass to determine when there are any differences in hemodynamic effects if CaCl(2) 20 mg/kg and protamine 5mg/kg are mixed together and infused over 10 min versus administering half of the calcium dose (10 mg/kg) as a bolus followed by a 10-min infusion of protamine 5 mg/kg and CaCl(2) 10mg/kg.

Alternative techniques for surgical management of recoarctation

OBJECTIVE

To evaluate the different surgical options in patients with recoarctation and minimal collaterals.

METHODS

Thirty-three cases operated on between January 1980 and January 1995 were reviewed. Initial repair was end-to-end anastomosis in 16 patients, subclavian artery aortoplasty in 10, synthetic patch aortoplasty in 4 and bypass conduit in 3 patients. Age at reoperation was 7.5 +/- 5.2 years (1-17 years). Pressure gradient was 20-48 Torr (33 +/- 9). Upper extremity resting or exercise systemic hypertension was present in all. In 18 patients recoarctation was repaired using subclavian artery aortoplasty (n = 15) or synthetic patch aortoplasty (n = 3); alone in 9, with temporary heparinized bypass in 2, or in addition to placement of ascending aorta to descending aorta conduit as a permanent bypass through a left thoracotomy in 9. In 13 patients a conduit was interposed between ascending aorta and descending aorta through a right thoracotomy. In one patient recoarctation segment was patched on cardiopulmonary bypass through a midsternotomy.

RESULTS

There was no mortality or complications. All patients had no echocardiographic pressure gradients across recoarctation on 5 +/- 3.4 years follow-up. Persistent systemic hypertension following recoarctation repair was present in 3/8 patients (37%) operated on at age greater than 10 years, but has been resolved in all 25 patients less than 10 years of age (P = 0.02).

CONCLUSIONS

Use of ascending aorta to descending aorta conduit, either alone through a right thoracotomy, or as permanent bypass in combination with patching the recoarctation through a left thoracotomy provides safe and excellent relief of obstruction.

Color Doppler flow mapping of the patent ductus arteriosus in very low birthweight neonates: echocardiographic and clinical findings

Forty-eight preterm infants (mean birthweight 1.0 +/- 0.3 kg; mean gestational age 28 +/- 3 weeks) underwent serial echocardiograms and physical examinations in order to determine the correlation between color Doppler flow mapping (CDFM) results and physical findings of a patent ductus arteriosus (PDA), the predictive value of early CDFM as an indicator of subsequent requirement for treatment of a PDA, and to determine the direction and duration of ductal shunting and the rate of ductal closure and opening. CDFM analysis and cardiac physical examination of left-to-right ductal shunting were usually concordant in infants with a large PDA shunt, the most reliable physical finding being increased precordial activity. CDFM studies on day 2 or 3 of postnatal life had prognostic value with regard to subsequent need for closing the PDA. Additional findings included the absence of right-to-left PDA shunting in infants < 1 kg and < 28 weeks gestation and the absence of ductal reopening in infants in whom it had closed spontaneously. After complete PDA closure using indomethacin, subsequent ductal reopening is uncommon, except in infants < 25 weeks gestation and < 700 g bodyweight.

Extended aortic valvuloplasty for recurrent valvular stenosis and regurgitation in children

Recurrent significant aortic valvular stenosis or regurgitation, or both, after balloon or open valvotomy in pediatric patients often necessitates aortic valve replacement. In an attempt to preserve the aortic valve, we performed extended aortic valvuloplasty in 21 children with recurrent aortic valve stenosis or regurgitation from January 1989 to March 1993. Previous related procedures were one open aortic valvotomy or more (n = 15), balloon valvotomy (n = 4), balloon valvotomy after surgical valvotomy (n = 1), and repair of iatrogenic valve tear (n = 1). Mean age at the time of the extended aortic valvuloplasty was 6 +/- 3.4 years. Mean pressure gradient across the aortic valve was 56 +/- 12 torr. Regurgitation was moderate (grade 2 to 3) in nine and severe (grade 4) in 12 patients. Extended aortic valvuloplasty techniques consisted of thinning of valve leaflets (n = 15), augmentation of scarred and retracted leaflets with autologous pericardium (n = 11), resuspension of the augmented leaflet (n = 14), release of the rudimentary commissure from the aortic wall (n = 5), extension of the valvotomy incision into the aortic wall on both sides of the commissure (n = 20), patch repair of the sinus of Valsalva perforation (n = 1), reapproximation of tears (n = 5), and narrowing of the ventriculoaortic junction (n = 2). No operative deaths occurred. The postoperative mean pressure gradient, assessed by most recent Doppler echocardiography or cardiac catheterization at a follow-up of 18 +/- 6 months, was 19 +/- 6 torr (p < 0.01 versus the preoperative gradient). Aortic regurgitation was absent in 13, mild in 6, and moderate-to-severe, necessitating subsequent aortic valve replacement, in 2. This short-term experience indicates that extended aortic valvuloplasty is a safe and effective surgical approach that minimizes the need for aortic valve replacement in children with significant recurrent aortic valve stenosis or regurgitation.

Intraoperative echocardiography for evaluation of congenital heart defects in infants and children

To determine the accuracy, utility, and limitations of intraoperative transesophageal echocardiography (TEE) in infants and children, we performed prebypass and postbypass TEE in 90 children undergoing surgical repair of congenital heart lesions, comparing the results to those obtained using intraoperative epicardial echocardiography and pre- and postoperative precordial echocardiography. Patients ranged in age from 4 days to 21 yr (mean 4.1 yr) and in weight from 3 to 68 kg (mean 15.4 kg). Prebypass, we obtained high-quality, two-dimensional TEE images in 86 patients, with correction of the preoperative precordial diagnosis in 3 and confirmation of the preoperative diagnosis in the rest. Adequate epicardial images were obtained in 78 patients, with confirmation of the preoperative diagnosis in all. Shunt lesions that were well delineated prebypass by both TEE and epicardial imaging included interatrial, interventricular, and atrioventricular septal defect lesions. TEE failed to detect the exact size and location of lesions involving the right ventricular outflow tract, i.e., doubly committed subarterial (supracristal) ventricular septal defects. Regurgitant lesions (n = 30) were identified and their severity evaluated in all patients by both TEE and epicardial imaging. Obstructive lesions (n = 33), excluding those involving the right ventricular outflow tract, were well defined by both echocardiographic approaches. Postbypass, we obtained high-quality, two-dimensional, color and Doppler TEE images in 86 patients and epicardial images in 78 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Conal enlargement for diffuse subaortic stenosis

Twelve patients underwent conal enlargement for diffuse subaortic stenosis over a 3 1/2-year period. The subaortic stenosis was due to tunnel outflow in 11 and malattached mitral valve in one. Mean age was 4.4 +/- 4 years and mean subaortic gradient was 50 +/- 21 mm Hg. Three infants had a malalignment ventricular septal defect. In eight patients significant obstruction occurred 2 to 7 years (mean 4 +/- 2) after simple resection of subaortic stenosis (n = 2), ventricular septal defect closure (n = 2), ventricular septal defect closure and subaortic stenosis resection (n = 2), and canal repair (n = 2). In three infants the tunnel outflow distal to a malalignment ventricular septal defect was enlarged and closed with the defect. In three patients with subaortic stenosis proximal to a previously repaired ventricular septal defect, transatrial conal enlargement through the ventricular septal defect was performed. Another patient without a ventricular septal defect had transatrial conal enlargement. The remaining five patients had the modified Konno procedure. Two patients had postoperative complete heart block and one infant had insertion of an apicoaortic conduit for aortic anulus hypoplasia 9 months later. One patient died of pneumonia during the follow-up period. Postoperative echographic outflow gradients up to 3 1/2 years (mean 1.2 +/- 1) ranged up to 25 mm Hg (mean 7 +/- 11) and were mainly at the aortic level. The 11 surviving patients are doing well up to 3 1/2 years of follow-up (mean 1.5 +/- 1). We conclude that conal enlargement procedures with aortic valve preservation are preferable, effective, and can be safely performed for diffuse subaortic stenosis in infants and children.

Intraoperative transesophageal echocardiography of ventricular septal defect

The accuracy and limitations of intraoperative two-dimensional (2-D) and color Doppler flow mapping transesophageal echocardiography (TEE) of ventricular septal defect (VSD), before and after cardiopulmonary bypass, were analyzed in 62 children. Twenty-one patients had an isolated VSD, and 41 had a VSD plus additional cardiac anomalies. Two-dimensional and color Doppler flow mapping TEE were performed with a miniaturized 5-MHz single (transverse) plane transducer in the 51 of 62 patients weighing less than 20 kg. The remaining 11 were monitored using a single plane adult probe (n = 4) and a biplane (transverse plus longitudinal) probe (N = 7). Prebypass TEE provided a correct diagnosis in 57 of 62 cases (92%) and corrected an erroneous preoperative transthoracic echocardiographic diagnosis in three of 62 cases (5%). Single plane TEE diagnosis was erroneous in five patients: four with doubly-committed subarterial VSD and one with multiple small apical muscular defects and pulmonary hypertension. Biplane TEE (transverse longitudinal) provided clear and complete imaging of the right ventricular outflow tract in all seven cases in whom it was used. Postbypass TEE showed absence of a hemodynamically significant residual VSD in 30 of 40 patients (95%) who underwent VSD patch closure, prospectively identified two of 40 with significant residual VSD, and accurately measured the color Doppler jet width of all residual VSDs. We conclude that hemodynamically significant VSDs can be identified immediately after cardiopulmonary bypass based on the width of the residual VSD color Doppler flow map jet. Therefore, 2-D and color Doppler flow mapping TEE provide an accurate diagnosis in most cases of VSD but may miss doubly-committed subarterial and apical muscular VSD unless biplane TEE is used.

Advantages of early relief of subaortic stenosis in single ventricle equivalents

Thirteen patients with single ventricle equivalents and subaortic stenosis underwent relief of the stenosis and subsequent Fontan operation. Nine patients, group 1, had the obstruction relieved at 3.6 +/- 1.6 years of age whenever the pressure gradient became apparent. Four patients, group 2, had the subaortic stenosis operated on at the neonatal period, 10.5 +/- 10 days old, before hemodynamic evidence of obstruction. Preoperative pressure gradient across the outflow tract was 44.2 +/- 4.7 mm Hg in group 1 versus 4.7 +/- 5 mm Hg in group 2 (p = 0.002). Ventricular muscle mass was 186% +/- 18% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.0001), and mass/volume ratio was 1.12 +/- 0.62 in group 1 versus 0.62 +/- 0.16 in group 2 (p = 0.003). Relief of subaortic stenosis was achieved by proximal pulmonary artery to ascending aorta or aortic arch anastomosis and by systemic to distal pulmonary artery shunt. There was no hospital mortality or complication related to the procedure. At evaluation before Fontan operation, 4.3 +/- 1.6 years after relief of subaortic stenosis in group 1 and 3.2 +/- 0.9 years in group 2, the pressure gradient across the ventricular outflow tract was 4 +/- 3 mm Hg in group 1 versus 3 +/- 2 mm Hg in group 2 (p = not significant), ventricular muscle mass was 184% +/- 31% in group 1 versus 114% +/- 5% of normal in group 2 (p = 0.003), and the mass/volume ratio was 1.17 +/- 0.2 in group 1 versus 0.62 +/- 0.2 in group 2 (p = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Extended aortic valvuloplasty: a new approach for the management of congenital valvar aortic stenosis

A new technique for the treatment of congenital valvar aortic stenosis is described. It consists of augmenting the aortic cusp by extending the commissurotomy incision into the aortic wall around the leaflet insertion, mobilizing the valve cusp attachment at the commissures, and freeing the aortic insertion of the rudimentary commissure. The results of standard valvotomy performed on 48 patients (group 1) were compared with those of the new extended valvuloplasty carried out on 16 patients (group 2). The two groups were comparable in age at operation (2.7 +/- 2.1 years for group 1 versus 2.1 +/- 1.7 years for group 2; p = not significant) and in preoperative pressure gradient (58 +/- 25 mm Hg for group 1 versus 61 +/- 36 mm Hg for group 2; p = not significant). There was no operative mortality in either group. Follow-up is available on all patients, with a mean of 4.3 +/- 2.6 years for group 1 versus 1.7 +/- 0.5 years for group 2 (p = 0.05). There was one late death in group 1. Postoperative gradient was 47 +/- 13 mm Hg in group 1 versus 19 +/- 13 mm Hg in group 2 (p = 0.05). Moderate or severe regurgitation was present in 18 patients (38%) in group 1 and 2 patients (13%) in group 2 (p = not significant). Reoperation was needed in 8 patients (17%) in group 1 versus 2 patients (13%) in group 2 (p = not significant). The described valvuloplasty procedure addresses the unique pathological features of valvar aortic stenosis and provides better relief of the obstruction than the presently available techniques. Longer follow-up is needed to determine the late results of this approach.

Resternotomy in patients with valved conduits adherent to the sternum

Twenty-two patients with valved conduits adherent to the sternum underwent resternotomy. Mean age was 10 +/- 6 years, and mean conduit age was 4 +/- 4 years. Diagnoses were D-transposition (7), truncus arteriosus (7), univentricular heart (6), Taussig-Bing anomaly (1), and corrected transposition (1). The majority of patients (68%) had reoperation for outgrown or degenerated conduits. In 17 patients, the sternum was opened with a chisel. Two of these patients sustained conduit neointimal collapse from manipulation, and 3 had conduit tear requiring immediate cardiopulmonary bypass through the femoral vessels. In the last 5 patients, the sternum was opened above and below the conduit, and the inner table was chiseled and left attached to the conduit avoiding injury and undue conduit manipulation. Cardiopulmonary bypass and operation were carried out uneventfully. We believe that the recent technique described provides a safe alternative approach to valved conduits adherent to the sternum.