The ABCD stop signal data: Response to Bissett et al

This paper responds to a recent critique by Bissett et al. of the fMRI Stop task used in the Adolescent Brain Cognitive Development℠ Study (ABCD Study®). The critique focuses primarily on a task design feature related to race model assumptions (i.e., that the Go and Stop processes are fully independent). In response, we note that the race model is quite robust against violations of its assumptions. Most importantly, while Bissett raises conceptual concerns with the task we focus here on analyzes of the task data and conclude that the concerns appear to have minimal impact on the neuroimaging data (the validity of which do not rely on race model assumptions) and have far less of an impact on the performance data than the critique suggests. We note that Bissett did not apply any performance-based exclusions to the data they analyzed, a number of the trial coding errors they flagged were already identified and corrected in ABCD annual data releases, a number of their secondary concerns reflect sensible design decisions and, indeed, their own computational modeling of the ABCD Stop task suggests the problems they identify have just a modest impact on the rank ordering of individual differences in subject performance.

Baseline brain function in the preadolescents of the ABCD Study

The Adolescent Brain Cognitive Development (ABCD) Study® is a 10-year longitudinal study of children recruited at ages 9 and 10. A battery of neuroimaging tasks are administered biennially to track neurodevelopment and identify individual differences in brain function. This study reports activation patterns from functional MRI (fMRI) tasks completed at baseline, which were designed to measure cognitive impulse control with a stop signal task (SST; N = 5,547), reward anticipation and receipt with a monetary incentive delay (MID) task (N = 6,657) and working memory and emotion reactivity with an emotional N-back (EN-back) task (N = 6,009). Further, we report the spatial reproducibility of activation patterns by assessing between-group vertex/voxelwise correlations of blood oxygen level-dependent (BOLD) activation. Analyses reveal robust brain activations that are consistent with the published literature, vary across fMRI tasks/contrasts and slightly correlate with individual behavioral performance on the tasks. These results establish the preadolescent brain function baseline, guide interpretation of cross-sectional analyses and will enable the investigation of longitudinal changes during adolescent development.

Polygenic risk for psychiatric disorders correlates with executive function in typical development

Executive functions are a diverse and critical suite of cognitive abilities that are often disrupted in individuals with psychiatric disorders. Despite their moderate to high heritability, little is known about the molecular genetic factors that contribute to variability in executive functions and how these factors may be related to those that predispose to psychiatric disorders. We examined the relationship between polygenic risk scores built from large genome-wide association studies of psychiatric disorders and executive functioning in typically developing children. In our discovery sample (N = 417), consistent with previous reports on general cognitive abilities, polygenic risk for autism spectrum disorder was associated with better performance on the Dimensional Change Card Sort test from the NIH Cognition Toolbox, with the largest effect in the youngest children. Polygenic risk for major depressive disorder was associated with poorer performance on the Flanker test in the same sample. This second association replicated for performance on the Penn Conditional Exclusion Test in an independent cohort (N = 3681). Our results suggest that the molecular genetic factors contributing to variability in executive function during typical development are at least partially overlapping with those associated with psychiatric disorders, although larger studies and further replication are needed.

Genome-wide association study of shared components of reading disability and language impairment

Written and verbal languages are neurobehavioral traits vital to the development of communication skills. Unfortunately, disorders involving these traits-specifically reading disability (RD) and language impairment (LI)-are common and prevent affected individuals from developing adequate communication skills, leaving them at risk for adverse academic, socioeconomic and psychiatric outcomes. Both RD and LI are complex traits that frequently co-occur, leading us to hypothesize that these disorders share genetic etiologies. To test this, we performed a genome-wide association study on individuals affected with both RD and LI in the Avon Longitudinal Study of Parents and Children. The strongest associations were seen with markers in ZNF385D (OR = 1.81, P = 5.45 × 10(-7) ) and COL4A2 (OR = 1.71, P = 7.59 × 10(-7) ). Markers within NDST4 showed the strongest associations with LI individually (OR = 1.827, P = 1.40 × 10(-7) ). We replicated association of ZNF385D using receptive vocabulary measures in the Pediatric Imaging Neurocognitive Genetics study (P = 0.00245). We then used diffusion tensor imaging fiber tract volume data on 16 fiber tracts to examine the implications of replicated markers. ZNF385D was a predictor of overall fiber tract volumes in both hemispheres, as well as global brain volume. Here, we present evidence for ZNF385D as a candidate gene for RD and LI. The implication of transcription factor ZNF385D in RD and LI underscores the importance of transcriptional regulation in the development of higher order neurocognitive traits. Further study is necessary to discern target genes of ZNF385D and how it functions within neural development of fluent language.

Recovery of white matter tracts in regions of peritumoral FLAIR hyperintensity with use of restriction spectrum imaging

BACKGROUND AND PURPOSE

DTI is being increasingly used to visualize critical white matter tracts adjacent to brain tumors before neurosurgical resection. However, brain tumors, particularly high-grade gliomas, are typically surrounded by regions of FLAIR hyperintensity that include edema, which increase isotropic diffusion, degrading the ability of standard DTI to uncover orientation estimates within these regions. We introduce a new technique, RSI, which overcomes this limitation by removing the spherical, fast diffusion component introduced by edema, providing better analysis of white matter architecture.

MATERIALS AND METHODS

A total of 10 patients with high-grade gliomas surrounded by FLAIR-HI that at least partially resolved on follow-up imaging were included. All patients underwent RSI and DTI at baseline (FLAIR-HI present) and at follow-up (FLAIR-HI partially resolved). FA values obtained with RSI and DTI were compared within regions of FLAIR-HI and NAWM at both time points.

RESULTS

RSI showed higher FA in regions of FLAIR-HI and NAWM relative to DTI, reflecting the ability of RSI to specifically measure the slow, restricted volume fraction in regions of edema and NAWM. Furthermore, a method by time interaction revealed that FA estimates increased when the FLAIR-HI resolved by use of standard DTI but remained stable with RSI. Tractography performed within the region of FLAIR-HI revealed the superior ability of RSI to track fibers through severe edema relative to standard DTI.

CONCLUSIONS

RSI improves the quantification and visualization of white matter tracts in regions of peritumoral FLAIR-HI associated with edema relative to standard DTI and may provide a valuable tool for neurosurgical planning.

CETP polymorphisms associate with brain structure, atrophy rate, and Alzheimer's disease risk in an APOE-dependent manner

Two alleles in cholesteryl ester transfer protein (CETP) gene polymorphisms have been disputably linked to enhanced cognition and decreased risk of Alzheimer's disease (AD): the V and A alleles of I405V and C-629A. This study investigates whether these polymorphisms affect brain structure in 188 elderly controls and 318 AD or mild cognitive impairment (MCI) subjects from the Alzheimer's Disease Neuroimaging Initiative cohort. Nominally signficant associations were dependent on APOE ε4 carrier status. In APOE ε4 carriers, the V and A alleles, both of which decrease CETP and increase HDL, associated with greater baseline cortical thickness and less 12-month atrophy in the medial temporal lobe. Conversely, in APOE ε4 non-carriers, the I allele, which increases CETP and decreases HDL, associated with greater baseline thickness, less atrophy and lower risk of dementia. These results suggest CETP may contribute to the genetic variability of brain structure and dementia susceptibility in an APOE-dependent manner.

Global clinical dementia rating of 0.5 in MCI masks variability related to level of function

OBJECTIVE

To evaluate whether ratings on Clinical Dementia Rating (CDR) items related to instrumental activities of daily living (IADL) are associated with cognitive or brain morphometric characteristics of participants with mild cognitive impairment (MCI) and global CDR scores of 0.5.

METHODS

Baseline cognitive and morphometric data were analyzed for 283 individuals with MCI who were divided into 2 groups (impaired and intact) based on their scores on the 3 CDR categories assessing IADL. Rates of progression to Alzheimer disease (AD) over 2 years were also compared in the 2 groups.

RESULTS

The impaired IADL MCI group showed a more widespread pattern of gray matter loss involving frontal and parietal regions, worse episodic memory and executive functions, and a higher percentage of individuals progressing to AD than the relatively intact IADL MCI group.

CONCLUSIONS

The results demonstrate the importance of considering functional information captured by the CDR when evaluating individuals with MCI, even though it is not given equal weight in the assignment of the global CDR score. Worse impairment on IADL items was associated with greater involvement of brain regions beyond the mesial temporal lobe. The conventional practice of relying on the global CDR score as currently computed underutilizes valuable IADL information available in the scale, and may delay identification of an important subset of individuals with MCI who are at higher risk of clinical decline.

Changes in fiber tract integrity and visual fields after anterior temporal lobectomy

OBJECTIVE

To investigate postoperative changes in fiber tract integrity in patients with temporal lobe epilepsy (TLE) following anterior temporal lobectomy (ATL) and to determine whether postoperative changes are 1) stable vs progressive and 2) related to visual field defects.

METHODS

Diffusion tensor imaging (DTI) was obtained in 7 patients with TLE before, 2 months after, and 1 year after ATL. Changes in fractional anisotropy (FA) were evaluated in a whole-brain voxel-wise analysis, as well within specific fiber tracts. Repeated-measures analysis of variance was performed to examine the time course of FA changes within ipsilateral and contralateral fiber tracts. Quantitative visual field analysis was performed to determine whether decreases in regional FA were related to the extent or location of visual field defects.

RESULTS

Patients showed decreased FA 2 months post-ATL in ipsilateral fiber tracts transected during surgery (parahippocampal cingulum, uncinate fasciculus, inferior longitudinal fasciculus, and fornix), as well as in fiber tracts not directly transected (inferior fronto-occipital fasciculus and corpus callosum). Additional decreases in FA were not observed from 2 months to 1 year post-ATL. Visual field defects in most patients were characterized by incomplete quadrantanopsias. However, FA reductions in one patient extended into temporo-occipital cortex and the splenium of the corpus callosum and were associated with a complete hemianopia.

CONCLUSIONS

Wallerian degeneration is apparent 2 months following unilateral ATLs in ipsilateral fibers directly and indirectly affected during surgery. These changes do not appear to progress over the course of a year, but may correlate with the nature and extent of postoperative visual field defects.

Six-month atrophy in MTL structures is associated with subsequent memory decline in elderly controls

Neurodegeneration precedes the onset of dementias such as Alzheimer's by several years. Recent advances in volumetric imaging allow quantification of subtle neuroanatomical change over time periods as short as six months. This study investigates whether neuroanatomical change in medial temporal lobe subregions is associated with later memory decline in elderly controls. Using high-resolution, T1-weighted magnetic resonance images acquired at baseline and six-month follow-up, change in cortical thickness and subcortical volumes was measured in 142 healthy elderly subjects (aged 59-90 years) from the ADNI cohort. Regression analysis was used to identify whether change in fourteen subregions, selected a priori, was associated with declining performance on memory tests from baseline to two-year follow-up. Percent thickness change in the right fusiform and inferior temporal cortices and expansion of the right inferior lateral ventricle were found to be significant predictors of subsequent decline on memory-specific neuropsychological measures. These results demonstrate that six-month regional neurodegeneration can be quantified in the healthy elderly and might help identify those at risk for subsequent cognitive decline.

Combining MR imaging, positron-emission tomography, and CSF biomarkers in the diagnosis and prognosis of Alzheimer disease

BACKGROUND AND PURPOSE

Different biomarkers for AD may potentially be complementary in diagnosis and prognosis of AD. Our aim was to combine MR imaging, FDG-PET, and CSF biomarkers in the diagnostic classification and 2-year prognosis of MCI and AD, by examining the following: 1) which measures are most sensitive to diagnostic status, 2) to what extent the methods provide unique information in diagnostic classification, and 3) which measures are most predictive of clinical decline.

MATERIALS AND METHODS

ADNI baseline MR imaging, FDG-PET, and CSF data from 42 controls, 73 patients with MCI, and 38 patients with AD; and 2-year clinical follow-up data for 36 controls, 51 patients with MCI, and 25 patients with AD were analyzed. The hippocampus and entorhinal, parahippocampal, retrosplenial, precuneus, inferior parietal, supramarginal, middle temporal, lateral, and medial orbitofrontal cortices were used as regions of interest. CSF variables included Abeta42, t-tau, p-tau, and ratios of t-tau/Abeta42 and p-tau/Abeta42. Regression analyses were performed to determine the sensitivity of measures to diagnostic status as well as 2-year change in CDR-SB, MMSE, and delayed logical memory in MCI.

RESULTS

Hippocampal volume, retrosplenial thickness, and t-tau/Abeta42 uniquely predicted diagnostic group. Change in CDR-SB was best predicted by retrosplenial thickness; MMSE, by retrosplenial metabolism and thickness; and delayed logical memory, by hippocampal volume.

CONCLUSIONS

All biomarkers were sensitive to the diagnostic group. Combining MR imaging morphometry and CSF biomarkers improved diagnostic classification (controls versus AD). MR imaging morphometry and PET were largely overlapping in value for discrimination. Baseline MR imaging and PET measures were more predictive of clinical change in MCI than were CSF measures.

Side matters: diffusion tensor imaging tractography in left and right temporal lobe epilepsy

BACKGROUND AND PURPOSE

Noninvasive imaging plays a pivotal role in lateralization of the seizure focus in presurgical patients with temporal lobe epilepsy (TLE). Our goal was to evaluate the utility of diffusion tensor imaging (DTI) tractography in TLE.

MATERIALS AND METHODS

Twenty-one patients with TLE (11 right, 10 left TLE) and 21 controls were enrolled. A 1.5T MR imaging scanner was used to obtain 51 diffusion-gradient-direction images per subject. Eight pairs of white matter fiber tracts were traced, and fiber tract fractional anisotropy (FA) was calculated and compared with controls. Fiber tract FA asymmetry and discriminant function analysis were evaluated in all subjects and fiber tracts respectively.

RESULTS

Compared with controls, patients with TLE demonstrated decreased FA in 5 ipsilateral fiber tracts. Patients with left TLE had 6 ipsilateral and 4 contralateral fiber tracts with decreased FA. Patients with right TLE had 4 ipsilateral but no contralateral tracts with decreased FA compared with controls. Right-sided FA asymmetry was demonstrated in patients with right TLE for 5 fiber tracts, and left-sided asymmetry, for patients with left TLE for 1 fiber tract. Discriminant function analysis correctly categorized patients into left-versus-right TLE in 90% of all cases (100% correct in all patients without hippocampal sclerosis) by using uncinate fasciculus and parahippocampal fiber tracts.

CONCLUSIONS

We found widespread reductions in fiber tract FA in patients with TLE, which were most pronounced ipsilateral to the seizure focus. Patients with left TLE had greater, more diffuse changes, whereas patients with right TLE showed changes that were primarily ipsilateral. Disease was lateralized to a high degree independent of identifiable hippocampal pathology noted on conventional MR imaging.

Regional rates of neocortical atrophy from normal aging to early Alzheimer disease

OBJECTIVE

To evaluate the spatial pattern and regional rates of neocortical atrophy from normal aging to early Alzheimer disease (AD).

METHODS

Longitudinal MRI data were analyzed using high-throughput image analysis procedures for 472 individuals diagnosed as normal, mild cognitive impairment (MCI), or AD. Participants were divided into 4 groups based on Clinical Dementia Rating Sum of Boxes score (CDR-SB). Annual atrophy rates were derived by calculating percent cortical volume loss between baseline and 12-month scans. Repeated-measures analyses of covariance were used to evaluate group differences in atrophy rates across regions as a function of impairment. Planned comparisons were used to evaluate the change in atrophy rates across levels of disease severity.

RESULTS

In patients with MCI-CDR-SB 0.5-1, annual atrophy rates were greatest in medial temporal, middle and inferior lateral temporal, inferior parietal, and posterior cingulate. With increased impairment (MCI-CDR-SB 1.5-2.5), atrophy spread to parietal, frontal, and lateral occipital cortex, followed by anterior cingulate cortex. Analysis of regional trajectories revealed increasing rates of atrophy across all neocortical regions with clinical impairment. However, increases in atrophy rates were greater in early disease within medial temporal cortex, whereas increases in atrophy rates were greater at later stages in prefrontal, parietal, posterior temporal, parietal, and cingulate cortex.

CONCLUSIONS

Atrophy is not uniform across regions, nor does it follow a linear trajectory. Knowledge of the spatial pattern and rate of decline across the spectrum from normal aging to Alzheimer disease can provide valuable information for detecting early disease and monitoring treatment effects at different stages of disease progression.

Diffusion tensor imaging correlates of memory and language impairments in temporal lobe epilepsy

OBJECTIVE

To investigate the relationship between white matter tract integrity and language and memory performances in patients with temporal lobe epilepsy (TLE).

METHODS

Diffusion tensor imaging (DTI) was performed in 17 patients with TLE and 17 healthy controls. Fractional anisotropy (FA) and mean diffusivity (MD) were calculated for six fiber tracts (uncinate fasciculus [UF], arcuate fasciculus [AF], fornix [FORX], parahippocampal cingulum [PHC], inferior fronto-occipital fasciculus [IFOF], and corticospinal tract [CST]). Neuropsychological measures of memory and language were obtained and correlations were performed to evaluate the relationship between DTI and neuropsychological measures. Hierarchical regression was performed to determine unique contributions of each fiber tract to cognitive performances after controlling for age and hippocampal volume (HV).

RESULTS

Increases in MD of the left UF, PHC, and IFOF were associated with poorer verbal memory in TLE, as were bilateral increases in MD of the AF, and decreases in FA of the right AF. Increased MD of the AF and UF, and decreased FA of the AF, UF, and left IFOF were related to naming performances. No correlations were found between DTI measures and nonverbal memory or fluency in TLE. Regression analyses revealed that several fibers, including the AF, UF, and IFOF, independently predicted cognitive performances after controlling for HV.

CONCLUSIONS

The results suggest that structural compromise to multiple fiber tracts is associated with memory and language impairments in patients with temporal lobe epilepsy. Furthermore, we provide initial evidence that diffusion tensor imaging tractography may provide clinically unique information for predicting neuropsychological status in patients with epilepsy.

Parietal and superior frontal visuospatial maps activated by pointing and saccades

A recent study from our laboratory demonstrated that parietal cortex contains a map of visual space related to saccades and spatial attention and identified this area as the likely human homologue of the lateral intraparietal (LIP). A human homologue for the parietal reach region (PRR), thought to preferentially encode planned hand movements, has also been recently proposed. Both of these areas, originally identified in the macaque monkey, have been shown to encode space with eye-centered coordinates. Functional magnetic resonance imaging (fMRI) of humans was used to test the hypothesis that the putative human PRR contains a retinotopic map recruited by finger pointing but not saccades and to test more generally for differences in the visuospatial maps recruited by pointing and saccades. We identified multiple maps in both posterior parietal cortex and superior frontal cortex recruited for eye and hand movements, including maps not observed in previous mapping studies. Pointing and saccade maps were generally consistent within single subjects. We have developed new group analysis methods for phase-encoded data, which revealed subtle differences between pointing and saccades, including hemispheric asymmetries, but we did not find evidence of pointing-specific maps of visual space.

Endovascular stent implantation in a coronary artery to pulmonary artery fistula in a patient with pulmonary atresia with ventricular septal defect and severe cyanosis

A 31-year-old male with pulmonary atresia, ventricular septal defect presented with exercise intolerance and severe cyanosis. A restrictive coronary-pulmonary artery fistula was identified as the main source of pulmonary blood flow. We report transcatheter stent implantation in the fistula to augment pulmonary flow as a palliative management option in the adult patient with complex congenital heart disease.

Properties of synchronous and asynchronous release during pulse train depression in cultured hippocampal neurons

Neurotransmitter release displays at least two kinetically distinct components in response to a single action potential. The majority of release occurs synchronously with action-potential-triggered Ca(2+) influx; however, delayed release--also called asynchronous release--persists for tens of milliseconds following the peak Ca(2+) transient. In response to trains of action potentials, synchronous release eventually declines, whereas asynchronous release often progressively increases, an effect that is primarily attributed to the buildup of intracellular Ca(2+) during repetitive stimulation. The precise relationship between synchronous and asynchronous release remains unclear at central synapses. To gain better insight into the mechanisms that regulate neurotransmitter release, we systematically characterized the two components of release during repetitive stimulation at excitatory autaptic hippocampal synapses formed in culture. Manipulations that increase the Ca(2+) influx triggered by an action potential--elevation of extracellular Ca(2+) or bath application of tetraethylammonium (TEA)--accelerated the progressive decrease in synchronous release (peak excitatory postsynaptic current amplitude) and concomitantly increased asynchronous release. When intracellular Ca(2+) was buffered by extracellular application of EGTA-AM, initial depression of synchronous release was equal to or greater than control; however, it quickly reached a plateau without further depression. In contrast, asynchronous release was largely abolished in EGTA-AM. The total charge transfer following each pulse--accounting for both synchronous and asynchronous release--reached a steady-state level that was similar between control and EGTA-AM. A portion of the decreased synchronous release in control conditions therefore was matched by a higher level of asynchronous release. We also examined the relative changes in synchronous and asynchronous release during repetitive stimulation under conditions that highly favor asynchronous release by substituting extracellular Ca(2+) with Sr(2+). Initially, asynchronous release was twofold greater in Sr(2+). By the end of the train, the difference was approximately 50%; consequently, the total release per pulse during the plateau phase was slightly larger in Sr(2+) compared with Ca(2+). We thus conclude that while asynchronous release--like synchronous release--is limited by vesicle availability, it may be able to access a slightly larger subset of the readily releasable pool. Our results are consistent with the view that during repetitive stimulation, the elevation of asynchronous release depletes the vesicles immediately available for release, resulting in depression of synchronous release. This implies that both forms of release share a small pool of immediately releasable vesicles, which is being constantly depleted and refilled during repetitive stimulation.

Late pulmonary valve replacement after repair of tetralogy of Fallot

BACKGROUND

Pulmonary regurgitation appears to be well tolerated early after repair of tetralogy of Fallot; however, it may result in progressive right ventricular dilatation and dysfunction necessitating eventual valve replacement. Our objective was to review our experience with late pulmonary valve replacement after complete repair of tetralogy of Fallot.

METHODS AND RESULTS

A total of 42 patients (16 female and 26 male) were operated on between July 1, 1974, and January 1, 1998. Mean age was 22 years (range 2-65 years). The mean interval between tetralogy repair and pulmonary valve replacement was 10.8 years (range 1.6 months-33 years). Mean follow-up was 7.8 +/- 6.0 years (maximum 23 years). Indications for pulmonary valve replacement included decreased exercise tolerance in 58%, right heart failure in 21%, arrhythmia in 14%, syncope in 10%, and progressive isolated right ventricular dilatation in 7%. Heterograft prostheses were used in 33 patients and homografts in 9. Five patients underwent isolated pulmonary valve replacement; concomitant procedures performed in 37 patients included tricuspid valve repair/replacement (n = 18), residual ventricular septal defect repair (n = 12), atrial septal defect closure (n = 4), pulmonary artery patch angioplasty (n = 17), and right ventricular outflow tract enlargement (n = 13). One patient died early (2%) of multiorgan failure. There were 6 late deaths, 3 of which were cardiac related. Survival was 95.1% +/- 3.4% and 76.4% +/- 8.9% at 5 and 10 years, respectively. Functional class of patients was improved significantly; preoperatively, 76% of patients were in New York Heart Association class III-IV, and after pulmonary valve replacement, 97% of surviving patients were in class I-II (P =.0001). Moderate to severe reduction in right ventricular function was noted on preoperative echocardiography in 59% and on late echocardiography in 18% (P =.03). Of the 5 patients who had supraventricular arrhythmias before pulmonary valve replacement, 1 had postoperative recurrence and the arrhythmia is controlled with antiarrhythmic therapy; the other 4 are in normal sinus rhythm at late follow-up. Eight patients subsequently underwent pulmonary valve re-replacement without early mortality at a mean interval of 9.0 +/- 4.2 years (range 3.8-16.8 years). Freedom from pulmonary valve re-replacement was 93.1% +/- 4.7% and 69.8% +/- 10.7% at 5 and 10 years, respectively. The only significant risk factor for re-replacement was young age at the time of the initial pulmonary valve replacement (P =.023).

CONCLUSION

Late pulmonary valve replacement after tetralogy repair significantly improves right ventricular function, functional class, and atrial arrhythmias, and it can be performed with low mortality. Subsequent re-replacement may be necessary to maintain functional improvement.

Palliated congenital heart disease

The group of patients with palliated complex forms of congenital heart disease presents a challenging and difficult management problem during the adolescent years. In patients not considered to be candidates for more fully palliated procedures that separate the circulations, a bidirectional caval pulmonary shunt, often associated with a systemic to pulmonary shunt, may provide significant palliation for several more decades. However, there remain a significant number of patients who, after some years, may develop increasing problems associated with myocardial failure and the development of serious atrial arrhythmias. Interventional cardiac catheterization combined with newer surgical techniques may return many of these patients to more satisfactory hemodynamic states. However, some patients during their adolescent years may eventually require cardiac transplantation for the long-term management of their complex congenital cardiac defects.

Device closure of fenestrated atrial septal defects: use of a single Amplatz atrial septal occluder after balloon atrial septostomy to create a single defect

Successful transcatheter device closure of secundum atrial septal defect has achieved worldwide acceptance with the clinical use of the Amplatz atrial septal occluder. However, device closure of multiple fenestrated secundum atrial septal defects remains a challenge for the interventionist and in some cases may be only effectively closed surgically. This case report of multiple fenestrated atrial septal defects represents a further expansion of technologic efforts to improve the results and simplify the mechanism of device closure of fenestrated defects. When device closure with more than one device seems impractical or disadvantageous, consolidation of multiple defects in a fenestrated fossa ovalis by simple balloon atrial septostomy as demonstrated by this case report provides an easy mechanism to allow implantation of a single large device which will effectively close all of the defects. This approach is similar to the surgical approach for resection of the fenestrated membrane with secondary patch closure of the enlarged defect. Excellent and complete closure of a fenestrated secundum atrial septal defect is illustrated in this case report.

[New methods of percutaneous closure of patent ductus arteriosus]

Various devices have been developed for the percutaneous closure of persistent patent ductus arteriosus (PDA). In recent years Gianturco coils have become increasingly widespread for this purpose. Poor control during positioning is a major disadvantage of Gianturco coils, with resultant embolization of coils and residual shunts. Very recently a new screwing detachable coil is available (Cook Cardiology, Europe). Between January 1996 and January 2000, 34 consecutive patients with PDA underwent cardiac catheterization. Thirty cases were judged suitable for this procedure, on the base of diameter and morphology of the ductus. Three cases were excluded because of the ductal diameter was too large (> 4.2 mm) and one because of its morphology (type B). In 28 patients a single coil was positioned, while in one case 2 coils were simultaneously used. In 29 cases (97%) complete closure was obtained (in 18 cases immediately, in 6 after 24 hours, in 5 after 1 month). One case showed a residual shunt and a second coil was applied eighteen months later with complete closure. So, considering also this last case, the closure was achieved in 100%. There were neither embolization or other complications. In conclusion, screwing detachable coil for PDA closure is a safe, very effective and at low cost technique. Therefore nowadays this procedure represents the method of choice for occlusion of small PDA (minimal diameter < or = 4 mm).

Remote telemedical interpretation of neonatal echocardiograms: impact on clinical management in a primary care setting

OBJECTIVE

The purpose of this study was to evaluate the utility of telemedical echocardiographically assisted neonatal cardiovascular evaluation in a primary care setting.

BACKGROUND

Neonates with congenital heart disease are frequently born far from pediatric subspecialty centers and can be clinically unstable at presentation. Recent advances in telecommunication technology have made it possible to transmit echocardiographic images over long distances. This technology may be beneficial to newborns with heart defects who are born in primary care centers.

METHODS

A retrospective review of all telemedical echocardiograms obtained from neonates (aged 1 day to 30 days) was performed. A telemedical link was created using a T-1 transmission line and a standard voice telephone line between the Mayo Clinic, Rochester, Minnesota (pediatric cardiology site), and the Altru Clinic, Grand Forks, North Dakota (primary care site), which is a general pediatric practice 400 miles from Rochester. Neonates with possible cardiac disorders were identified by the general pediatricians, who then requested telemedical echocardiography.

RESULTS

The 133 neonates had 161 T-1 echocardiograms. Median patient age was two days (range, one day to 29 days). One hundred thirty-two of 133 initial echocardiograms (99%) were obtained because of urgent indications. Transmitted images provided adequate diagnostic information in all patients. Seventy-nine neonates (59%) had a change in medical management or required cardiology follow-up. An immediate change in management occurred in 32 patients (24%), including seven in whom emergency transfer was either arranged or avoided.

CONCLUSIONS

Telemedical echocardiography provides accurate diagnostic data in neonates. Rapid telediagnosis facilitates appropriate care of sick neonates with possible congenital heart disease in the primary care setting. Unnecessary long-distance transfers can be avoided with this technology.

Percutaneous echocardiographically guided pericardiocentesis in pediatric patients: evaluation of safety and efficacy

The purpose of this study was to evaluate the safety and efficacy of echocardiographically (echo) guided pericardiocentesis in pediatric patients. Echo-guided pericardiocenteses performed in pediatric patients (age >/=16 years) at the Mayo Clinic between 1980 and 1997 were identified. Presentation, cause and characteristics of the effusion, details of the pericardiocentesis procedure, and outcome were determined by comprehensive chart review supplemented by telephone interviews when necessary. Seventy-three pediatric patients, median age 6.7 years (range 1 day to 16 years), underwent 94 consecutive echo-guided pericardiocenteses for effusions of various causes. Twenty-one (22%) procedures were performed in children younger than 2 years. All but 1 procedure were successful (99%). A mean fluid volume of 237 mL (range 4 to 970 mL) was withdrawn. Only a single attempt was needed for entry into the pericardial space in 87 (93%) procedures. No deaths were associated with the pericardiocentesis procedure. Only 1 major complication occurred (1%), a pneumothorax requiring chest tube reexpansion. Three (3%) minor complications-2 instances of right ventricular puncture and a small pneumothorax-did not require treatment. Extended catheter drainage for a mean of 5.2 +/- 4.5 days (range 1 to 19 days) was used with 30 (32%) of the 94 procedures. For the 52 patients who underwent pericardiocentesis without catheter drainage as the initial management strategy, 18 required 21 repeat pericardiocenteses for recurrence of effusion. In contrast, for the 21 patients who had pericardial catheterization as the initial management strategy, none had recurrences necessitating a repeat procedure (P <.001). Increased utilization of a pericardial catheter was associated with a concomitant decrease in the number of surgical pericardial procedures over the study period. Echo-guided pericardiocentesis was the only therapeutic modality for the management of effusion in 73% of all patients. Echo-guided pericardiocentesis is safe and effective in pediatric patients, including children younger than 2 years. The increasing use of pericardial catheterization in conjunction with this technique was associated with significant reduction of recurrence and decreased frequency of surgical interventions for treatment of pericardial effusion. Echo-guided pericardiocentesis with extended catheter drainage should be considered as primary management strategy for clinically significant pericardial effusions in pediatric patients.

Diastolic ventricular function in children: a Doppler echocardiographic study establishing normal values and predictors of increased ventricular end-diastolic pressure

OBJECTIVE

To extend noninvasive assessment of diastolic cardiac function into the pediatric age-group.

DESIGN

This study was divided into two phases, the first of which was designed to provide an age-appropriate set of normal diastolic Doppler echocardiographic data for children and adolescents and the second of which was to determine whether these Doppler techniques could be used to identify children with increased ventricular end-diastolic pressure (EDP).

MATERIAL AND METHODS

Complete echocardiographic studies focusing on Doppler variables of diastolic ventricular function were performed on 223 normal children. Values observed were analyzed for dependence on age, heart rate, and gender. Results from the normal group were then compared with Doppler values observed in a group of 24 children with catheterization-substantiated increases in ventricular EDP.

RESULTS

Normal values for the Doppler factors studied vary with both age and heart rate. The variables that most confidently distinguished children with increased EDP from normal subjects were the ratio of and the difference between the durations of pulmonary vein atrial reversal and the mitral A wave. A ratio of 1.2 or more or a difference of 29 ms or more identified those children with increased EDP with sensitivities of 88 and 90% and specificities of 86 and 86%, respectively.

CONCLUSION

Use of the normal data and the Doppler techniques described in this study will allow confident assessment of diastolic function in children as well as in adults.

A calcium signaling cascade essential for myosin thick filament assembly in Xenopus myocytes

Spontaneous calcium release from intracellular stores occurs during myofibrillogenesis, the process of sarcomeric protein assembly in striated muscle. Preventing these Ca2+ transients disrupts sarcomere formation, but the signal transduction cascade has not been identified. Here we report that specific blockade of Ca2+ release from the ryanodine receptor (RyR) activated Ca2+ store blocks transients and disrupts myosin thick filament (A band) assembly. Inhibition of an embryonic Ca2+/calmodulin-dependent myosin light chain kinase (MLCK) by blocking the ATP-binding site, by allosteric phosphorylation, or by intracellular delivery of a pseudosubstrate peptide, also disrupts sarcomeric organization. The results indicate that both RyRs and MLCK, which have well-described calcium signaling roles in mature muscle contraction, have essential developmental roles during construction of the contractile apparatus.

Protein-losing enteropathy after the Fontan operation: an international multicenter study. PLE study group

OBJECTIVE

This multicenter study retrospectively analyzes the data on 114 patients with protein-losing enteropathy after Fontan-type surgery. Special attention was given to the different treatment strategies used and their effect on outcome.

METHODS AND RESULTS

In 35 participating centers 3029 Fontan operations were performed. The incidence of protein-losing enteropathy in the survivors was 3.7%. The median age at Fontan-type surgery was 8.2 years (range: 0.6 to 32.9 years). Median age at diagnosis of protein-losing enteropathy was 11.7 years with a median time interval between surgery and diagnosis of 2.7 years (range: 0.1 to 16.4 years). Most patients had edema (79%) and effusions (75%). Hemodynamic data revealed a mean right atrial pressure of 17 +/- SD 5.3 mm Hg with a cardiac index of 2.4 +/- 0.8 L/min/m2. Medical treatment only (n = 52) resulted in a complete resolution of symptoms in 25%, no improvement in 29%, and death in 46%. Surgical treatment (n = 52) was associated with relief of protein-losing enteropathy in 19%, no improvement in 19%, and death in 62%. In 13 patients 16 percutaneous interventions were performed. This resulted in symptomatic improvement after 12 interventions and no improvement after 4 interventions.

CONCLUSIONS

We conclude that the current treatment of protein-losing enteropathy after Fontan operation is associated with a very high mortality and morbidity rate. Preventive strategies and new therapeutic approaches are necessary.

Acute results of balloon angioplasty of native coarctation versus recurrent aortic obstruction are equivalent. Valvuloplasty and Angioplasty of Congenital Anomalies (VACA) Registry Investigators

OBJECTIVES

This study sought to compare the immediate results and risk factors for suboptimal outcomes of percutaneous balloon angioplasty for native versus recurrent aortic obstruction.

BACKGROUND

Some cardiology centers have been reluctant to adopt balloon angioplasty for treatment of native aortic coarctation, while advocating balloon angioplasty over an operation for treatment of postsurgical or recurrent aortic obstruction.

METHODS

Acute results were analyzed from 970 procedures (422 native and 548 recurrent lesions) performed between 1982 and 1995 in 907 patients from 25 centers. An acute suboptimal outcome was defined as one or more of the following: residual systolic pressure gradient > or = 20 mm Hg, residual proximal to distal systolic pressure ration > or = 1.33 or a major complication (death, aortic transmural tear, stroke).

RESULTS

Bal loon angioplasty significantly (p = 0.0001) increased lesion diameter fo r both native (mean [+/= SD] 128 +/= 94%) and recurrent aortic obstruction (97 +/= 87%), with a significantly greater increase in the native group (p = 0.0001). A reduction in systolic pressure gradients was significant in both groups (p = 0.0001), but slightly higher (p = 0.01) for native (-74 +/- 24%) versus recurrent obstruction (-70 +/- 31%). Death associated with angioplasty was reported in 0.7% of patients with native and in 0.7% of patients with recurrent lesions (p = 1.00). An acute suboptimal outcome was noted with angioplasty in 19% of native and in 25% of recurrent lesions (p = 0.04). Significant independent risk factors included higher preangioplasty systolic gradient (odds ratio [OR] 1.39/10-mm Hg increment; 95% confidence interval [CI] 1.28 to 1.50, p = 0.0001), earlier study date (OR 0.92/1-year increment, 95% CI 1.02 to 1.26, p = 0.02) and recurrent obstruction (OR 1.39 vs. native lesions, 95% CI 1.00 to 1.94, p = 0.05).

CONCLUSIONS

Acute results and complications of balloon angioplasty of native coarctation appear to be equivalent or slightly superior to those of recurrent aortic obstructions.

Use of intravascular stents for superior vena caval obstruction after the Mustard operation

Obstruction of the systemic venous pathway is a complication in patients who have undergone the Mustard operation for complete transposition of the great arteries. In this report, we discuss intravascular stent placement in three patients for relief of superior vena caval obstruction after the Mustard operation. The clinical history, cardiac catheterization data, and echocardiographic data before and after stent placement are presented for each patient. Overall, four stents were placed. The mean gradients from the superior vena cava to the right atrium before stent placement were 10, 8, and 6 mm Hg, and they decreased to 3, 0, and 1 mm Hg immediately after stent placement. No complications occurred. Doppler echocardiographic assessment of mean gradients before and after stent placement correlated with the mean gradients determined by cardiac catheterization. Intravascular stent placement is effective for relief of baffle obstruction after the Mustard operation. Serial Doppler assessments of the gradient across the stent offer a noninvasive method for follow-up of these patients.

Improved early morbidity and mortality after Fontan operation: the Mayo Clinic experience, 1987 to 1992

OBJECTIVES

This study sought to evaluate changes in early morbidity and mortality as well as predictors of outcome in our most recent 339 patients undergoing modified Fontan operations.

BACKGROUND

The Fontan operation is the preferred definitive palliation for patients with functional single ventricles. Previously reported early mortality rates after Fontan operation have been substantial.

METHODS

Records of 339 consecutive patients who had a Fontan operation at the Mayo Clinic between 1987 and 1992 (recent cohort) were reviewed. This cohort was compared with the previous 500 patients who had Fontan operations performed between 1973 and 1986 (early cohort).

RESULTS

Recently, overall early mortality after Fontan has decreased significantly compared with that for the early cohort (from 16% to 9%, p = 0.002). This decline occurred despite increased anatomic complexity of patients. Short-term posthospital survival has also improved significantly in recent patients. One-year survival improved to 88% from 79%, and 5-year survival to 81% from 73% (p = 0.006). Patients with common atrioventricular valves and those who took daily preoperative diuretic medication or had either postoperative renal failure or elevated postbypass right atrial pressure were at increased risk for early mortality. Young age was not found to be a risk factor for early mortality. Early mortality for patients with heterotaxia decreased dramatically: recent 30-day mortality was 15% compared with 41% in the early heterotaxy cohort.

CONCLUSIONS

Many factors may have contributed to decreased early mortality after Fontan. Improved patient selection, younger age at time of operation, refinements in surgical techniques and postoperative management may all have had important roles. Proposed technical modifications of the Fontan operation must be evaluated in light of these improved results.

Protein-losing enteropathy after the Fontan operation: successful treatment by percutaneous fenestration of the atrial septum

Protein-losing enteropathy (PLE) after the Fontan operation is a life-threatening complication that may be refractory to medical therapy. Herein we describe a percutaneous atrial fenestration that was performed in a 42-year-old man with a double-inlet left ventricle who had undergone a Fontan operation 9 years earlier. Severe PLE developed, and despite frequent infusions of protein, his albumin level was 1.8 g/dL. The diagnosis of PLE was confirmed by an alpha(1)-antitrypsin clearance of 425 mL in 24 hours (normal 27 or less). Percutaneous atrial fenestration resulted in dramatic clinical improvement and resolution of the PLE. At 5-month follow-up, the patient's albumin level was 4.2 g/dL, his alpha(1)-antitrypsin clearance was normal, and he was free of ascites and edema.

Core curriculum for the training of pediatric invasive/interventional cardiologists: report of the Society for Cardiac Angiography and Interventions Committee on Pediatric Cardiology Training Standards

Within the field of pediatric cardiology, a number of subspecialty fields are generally recognized. Some of these overlap. For example, most electrophysiologists also would consider themselves to be clinical cardiologists. Some fields, however, are relatively mutually exclusive. For example, most clinical pediatric cardiologists would not consider themselves to be electrophysiologists and would admit that there is a different knowledge, skill, and experience base that separates an electrophysiologist from other specialists within the broader field of pediatric cardiology. Likewise, it is our opinion that a separate knowledge, skill, and experience base exists among pediatric Invasive/Interventional cardiologists. The purpose of this report is to define the unique knowledge and skill base required for the training of an invasive pediatric cardiologist. The scope of this report is limited to the training of Invasive/Interventional cardiologists dealing with the treatment of pediatric patients and the cardiac diseases most often encountered in these patients. This report describes in detail the core curriculum suggested for the training of an invasive pediatric cardiologist. For these purposes, invasive pediatric cardiology encompasses all aspects of pediatric diagnostic cardiac catheterization, whether congenital or acquired. Additional curriculum regarding training for therapeutic or interventional procedures is also addressed because of today's needs: most pediatric cardiac catheterizations are performed to acquire specific data that cannot be obtained otherwise by non-invasive technologies and are required for the best medical or surgical management. However, more and more frequently the need for a cardiac catheterization entertains the possibility of having to proceed with an interventional procedure, and therefore, to conserve the vessels of pediatric patients as well as to consider costs, any invasive pediatric cardiologist should be well trained in most of the accepted interventional pediatric cardiology procedures. The curricula is divided here into five major sections followed by a bibliography keyed to those sections. Also included is a suggested format for the objective evaluation and documentation of the progress of invasive pediatric cardiology fellows. It is intended to complement the core curriculum and provide a means for standardizing the evaluation of invasive pediatric cardiology fellows.

Biplane intraoperative transesophageal echocardiography in congenital heart disease

OBJECTIVE

To evaluate the accuracy, value, and safety of biplane intraoperative transesophageal echocardiography (TEE) in patients with congenital cardiac malformations.

DESIGN

We reviewed the results of the first 104 consecutive biplane intraoperative TEE examinations performed during the repair of congenital heart defects at the Mayo Clinic.

MATERIAL AND METHODS

TEE results were analyzed for accuracy of diagnosis, effect on the surgical procedure, and associated complications. In a subjective analysis, the relative contributions and advantages of each imaging plane (transverse and longitudinal) were also assessed.

RESULTS

Biplane TEE had "significant impact" on intraoperative management in 17 of 104 examinations (16.3%). Preoperative TEE altered the planned procedure in 11 patients (10.6%). Postbypass biplane TEE led to immediate revision of the initial repair in nine patients (8.7%). Patients who underwent modified Fontan operations or subaortic resections had the greatest frequency of significant impact (40% [P = 0.006] and 33% [P = 0.03], respectively). No major complications were associated with TEE. For a complete examination, use of both imaging planes was necessary in all the patients studied.

CONCLUSION

Biplane TEE is an accurate, valuable, and safe addition to the perioperative care of patients with congenital heart disease. Although intraoperative TEE is not needed in all operations for congenital heart disease, we recommend that biplane intraoperative TEE be performed routinely during modified Fontan procedures, subaortic resections, and other intracardiac operations for complex congenital cardiac malformations.

Imaging strategies for vascular rings

Thirty-nine patients have undergone operation for relief of tracheoesophageal compression resulting from vascular rings and related entities at the Mayo Clinic. Nineteen patients had a double aortic arch, 11 patients had a right aortic arch with an aberrant left subclavian artery, 5 patients had a left aortic arch with an aberrant right subclavian artery, 2 patients had a pulmonary artery sling, 1 patient had a right aortic arch with mirror-image branching and a left ligamentum arteriosum, and 1 patient had a left aortic arch, a right descending aorta, and a right ductus arteriosus. Diagnostic examinations included chest radiography, barium esophagography, angiography, and, more recently, transthoracic echocardiography, computed tomography, and magnetic resonance imaging. A comparison among the various diagnostic techniques used in 12 patients during the last 12 years showed that angiography (n = 7), magnetic resonance imaging (n = 5), and computed tomography (n = 3) were the most reliable, as they always accurately delineated the anatomy. However, in the 6 patients who underwent transthoracic echocardiography, 1 of whom was an older child and 2 of whom were adults, the vascular abnormality was described correctly only once; in the other 5 patients, the results were false-negative or the technique failed to visualize the relevant vascular structures sufficiently. Currently, magnetic resonance imaging is our imaging technique of choice for the delineation of the vascular and tracheal anatomy in patients suspected of having a vascular ring.

Distinguishing right from left: a standardized technique for fetal echocardiography

Improved echocardiographic equipment and increasing experience have led to accurate and reliable prenatal diagnosis of congenital defects and arrhythmias. However, without a standard convention for acquisition and presentation of fetal images, distinguishing the right side of the fetus from the left side can be difficult and confusing. This article proposes a standard method of image acquisition and presentation that allows confident determination of the fetal right/left axis by easily identified anatomic landmarks. This technique provides a reliable determination of the fetal right/left axis regardless of fetal position (i.e., face up, face down, facing left, or facing right), in both real time and retrospective review. Only after the fetal right/left axis has been determined can accurate diagnoses of fetal atrial and visceral situs, base-apex axis, and cardiac segmental anatomy be made.

Preoperative diagnosis of coronary artery anatomy in dextrotransposition of the great arteries

BACKGROUND

Preoperative diagnosis of the coronary artery pattern in dextrotransposition of the great arteries is important because deviation from the usual pattern may influence the surgical strategy.

METHODS

For assessment of the value of angiography and echocardiography in this setting, we analyzed the preoperative echocardiographic and angiographic findings in 74 patients with dextrotransposition of the great arteries in whom an arterial switch operation was performed.

RESULTS

Two-dimensional echocardiography established a diagnosis of the coronary artery pattern in 40 of the 74 patients; that diagnosis was correct in 38-30 of 32 (94%) with the usual coronary artery pattern and 8 (100%) with an atypical pattern. Angiography established a diagnosis of the coronary artery pattern in 52 patients; that diagnosis was correct in 50-41 of 42 (98%) with the usual coronary artery pattern and 9 of 10 (90%) with an atypical pattern. The accuracy of echocardiography in diagnosing the coronary artery pattern in dextrotransposition of the great arteries in this series was 95% and that of angiography was 96%.

CONCLUSION

Both echocardiography and angiography can establish the diagnosis of the coronary artery anatomy in most patients. Echocardiography is routinely performed in infants with dextrotransposition of the great arteries and is proving to be increasingly sensitive for diagnosing the coronary artery anatomy; the role of angiography may evolve to be supplementary, especially in cases in which the coronary artery anatomy is not clearly demonstrated by echocardiography.

Surgical treatment of vascular rings: the Mayo Clinic experience

From 1947 through 1992, 37 Mayo Clinic patients underwent operation for the relief of tracheoesophageal obstruction that resulted from vascular rings and related entities. Of the 37 patients, 18 had a double aortic arch, 11 had a right aortic arch with an aberrant left subclavian artery, 4 had a left aortic arch with an aberrant right subclavian artery, 2 had a pulmonary artery sling, 1 had a right aortic arch with mirror-image branching and a left ligamentum arteriosum, and 1 had a left aortic arch, a right descending aorta, and a right ductus arteriosus. Symptoms consisted of stridor, recurrent respiratory infections, and dysphagia. The anomaly was approached through a left thoracotomy in 31 patients, through a right thoracotomy in 4, and through a median sternotomy in 2. Only one early postoperative death (3%) and no late deaths occurred. At long-term follow-up (maximal duration, 45 years), three patients had residual symptomatic tracheomalacia, one of whom required right middle and lower lobectomy for recurrent pneumonia. Magnetic resonance imaging is the imaging technique of choice for accurate delineation of the vascular and tracheal anatomy. When patients are symptomatic, vascular ring should be repaired. The surgical risk is minimal, and the long-term results are excellent.

Surgical treatment of discrete and tunnel subaortic stenosis. Late survival and risk of reoperation

BACKGROUND

Although membranectomy, with or without septal myotomy or myectomy, has been the accepted method for treatment of fixed subaortic stenosis, controversies remain regarding operative methods and uncertainties regarding recurrence of subaortic obstruction and development of aortic insufficiency after repair.

METHODS AND RESULTS

To determine late survival and risk of reoperation, we reviewed 169 patients who, between 1957 and 1992, had repair of discrete (n = 108) and tunnel (n = 61) subaortic stenosis. One hundred fifty-four patients had their primary operation for subaortic stenosis at the Mayo Clinic, and 15 patients had their primary operation elsewhere. Among patients having initial repair at our institution, membranectomy was performed in 52 patients (33.8%), membranectomy plus myotomy in 24 patients (15.6%), membranectomy plus myectomy in 71 patients (46.1%), myectomy plus a Konno-Rastan procedure in 5 patients (3.2%), and myectomy plus a modified Konno-Rastan procedure in 2 patients (1.3%). For all patients, early mortality was 4.7% (2.7% since 1961), and during follow-up extending to 29 years, there have been 16 late deaths. Twenty-six patients underwent a second or third operation for recurrent left ventricular outflow obstruction, including 11 of the 154 who had their primary operation at the Mayo Clinic (7.1%). Among the 21 patients who had a discrete lesion at initial repair and required reoperation, 19 (92%) were noted to have tunnel obstruction at reoperation. At late follow-up, the left ventricular outflow tract gradient was higher in patients with tunnel versus discrete obstruction (33 +/- 5 versus 24 +/- 17 mm Hg, P < .04), and 10-year survival was poorer (79% versus 91%, P < .02). Ten-year survival was worse in patients with tunnel lesions and associated cardiac anomalies versus those with isolated tunnel subaortic stenosis (64% versus 92%, P < .005). Some degree of aortic valve insufficiency was seen at late follow-up in 26% of patients, but in most cases this was mild. For patients with discrete subaortic stenosis, risk of late aortic insufficiency was 38.6% after isolated membranectomy, 27.8% after membranectomy and myotomy, and only 7.3% after membranectomy and myectomy (P < .004). Progression of aortic insufficiency requiring aortic valve replacement occurred in only 6 patients.

CONCLUSIONS

Our results support the use of myectomy in conjunction with membranectomy for discrete subaortic stenosis. For restenosis and tunnel obstruction, more complete relief of subaortic stenosis by extended resection or a modified or classical Konno-Rastan procedure may improve late survival and reduce the incidence of recurrent subaortic stenosis and late aortic valve insufficiency.

Cor triatriatum: diagnosis, operative approach, and late results

From May 1960 to January 1992, 13 patients with cor triatriatum underwent surgical correction at the Mayo Clinic. Their ages ranged from 7 months to 57 years. Four patients had isolated cor triatriatum; three others had an associated patent foramen ovale or atrial septal defect. Six patients had major associated cardiac anomalies. In patients who had isolated cor triatriatum or associated anomalies with high pulmonary blood flow, the mean gradient across the left atrial diaphragm was 24.4 mm Hg, in comparison with 11.6 mm Hg in patients who had cor triatriatum and a connection between the common pulmonary venous chamber and the right atrium or associated cardiac anomalies that restricted pulmonary blood flow. In all 11 patients who underwent angiography, echocardiography, or both at our institution, the correct diagnosis was established preoperatively. Currently, echocardiography is the procedure of choice for diagnosing cor triatriatum. The diaphragm was excised through a left atrial approach in seven patients and through a right atriotomy in six. All associated anomalies were corrected. One critically ill patient who underwent an emergency operation in 1963 died early postoperatively, and one patient with chromosomal abnormalities and multiple cardiac defects died 2 months after an uneventful postoperative course. At the time of follow-up of the 11 long-term survivors, 9 were in New York Heart Association functional class I, and 2 (both of whom had major associated cardiac anomalies) were in class II. Postoperative angiography or echocardiography (in nine patients) showed no residual interatrial shunt or recurrent left atrial diaphragm.

Early and late results of the modified Fontan procedure for double-inlet left ventricle: the Mayo Clinic experience

Between May 1974 and March 1989, 155 patients with double-inlet left ventricle had the Fontan procedure performed at the Mayo Clinic. Age at operation ranged from nearly 2 to 41 years (median 10). The operative mortality rate from 1974 through 1980 (39 patients) was 21%, but from 1981 through 1989 (116 patients) it was reduced to 9%. The 17 late deaths were secondary to reoperation (n = 8), progressive myocardial failure (n = 5), sudden arrhythmia (n = 3) and bleeding varices (n = 1). Neither operative nor late mortality rate was significantly related to age at operation. At follow-up of 6 months to 11 years (mean 4.9 years) in 111 patients, 88% were in good or excellent condition and 12% were in fair or poor condition. The Fontan operation can be performed with a mortality risk of less than 10% in properly selected patients with double-inlet left ventricle. Late results are encouraging when contrasted with the clinical course of patients before this operative approach was utilized.

MR imaging of partial anomalous pulmonary venous connections

Magnetic resonance imaging was performed on 11 patients with partial anomalous pulmonary venous connections (PAPVC). Ten of these patients also had echocardiographic examinations, eight of which included color-flow Doppler studies. The diagnosis of PAPVC was confirmed in each of these patients by surgery or angiography. Fourteen anomalous pulmonary venous connections were identified, 10 involving the right upper lobe pulmonary vein and 4 involving the left upper lobe pulmonary vein. This retrospective review demonstrated that all 14 anomalous venous connections were correctly identified by MR imaging, whereas only 8 of 13 (62%) were identified by echocardiography. With MR, 89% of all the pulmonary veins and 93% of the anomalous pulmonary veins were visualized on axial images, while 41% of all pulmonary veins and 71% of anomalous veins were seen on coronal MR images. There were five atrial septal defects (ASDs), four of the sinus venous type and one of the septum secundum type. All five ASDs were correctly identified with MR imaging; three of four ASDs were identified with echocardiography. We conclude that MR imaging provides an accurate noninvasive method of depicting the anatomic abnormalities associated with PAPVC.

Echocardiographic segmental approach to complex congenital heart disease in the neonate

A segmental echocardiographic approach to complex congenital heart disease in the neonate allows accurate and precise assessment of intracardiac, as well as extracardiac, anomalies. Determination of abnormalities of atrial and visceral situs, as well as the cardiac situs, provides a fundamental background for the echocardiographic examination. Subsequently, a segmental approach allows precise determination of abnormalities of atrioventricular and ventricular great artery connections. Recent echocardiographic advances including high-frequency (7.5 and 10 MHz) and color flow imaging capabilities have dramatically improved our ability to accurately define abnormalities of anatomy and connection in the neonate. These advances now have expanded our previous echocardiographic criteria and allow application of the echocardiographic segmental approach to characterize complex congenital heart disease in the neonate.

Fontan operation in 176 patients with tricuspid atresia. Results and a proposed new index for patient selection

Between 1973 and March 1989, 176 patients with tricuspid atresia had the Fontan procedure performed at the Mayo Clinic. Age range at the time of surgery was 7 months to 42 years, with 43 patients (24%) 16 years old or older. Hospital mortality rates were 17% (nine of 54) from 1973 through 1980 and 8% (10 of 122) from 1981 through 1989. There have been 10 late cardiovascular deaths. Postoperative follow-up of 139 survivors (range, 6 months to 14 years; mean, 5.5 years) revealed 91% to be in excellent or good condition and 9% to be in fair or poor condition. Patients in fair or poor condition had poor stamina and/or fluid retention with intermittent pleural effusion, ascites, and so on. Two factors that clearly influence operative and late results are preoperative pulmonary arteriolar resistance (Rpa) and left ventricular diastolic function. A preoperative catheterization index devised by adding Rpa to left ventricular end-diastolic pressure divided by QpI plus QsI may be helpful in selecting candidates most likely to survive and benefit from the Fontan operation. In our experience, if this index is less than 4.0, then the postoperative right atrial mean pressure will be 20 mm Hg or less, a circumstance associated with 95% early and 89% overall survival rates.

Pediatric cardiac care consortium. Demonstrated value of a physician-directed quality assessment system

A quality assessment system for analyzing the results of inpatient care of children with cardiac abnormalities is described. Three Minnesota institutions (the Mayo Clinic, Minneapolis Children's Medical Center, and the University of Minnesota) participate with 15 other similar centers elsewhere in the United States in this system. Patient data are analyzed and adjusted for case mix to allow for differences in patient populations and referral patterns. The statistical methods used are shown for two conditions: ventricular septal defect and aortic valvotomy. Data presented show reduction in length of stay for cardiac catheterization. This change occurred as physicians annually reviewed and discussed the data and, as a result, instituted changes. This physician-directed program seeks improvement in patient care through physician education.