Post-acute day and night non-invasive respiratory intervention use and outcome: A brief report

PURPOSE

This study aimed to describe daytime and nighttime use and outcome of non-invasive respiratory intervention (NIRI) for infants born prematurely and for children with medical complexity (CMC) during a post-acute care hospital (PACH) admission.

METHODS

Thirty-eight initial PACH admissions (October 2018 through September 2020) for premature infants (< 1 year; n = 19) and CMC (> 1 year; n = 19) requiring NIRI during the day and/or at night were retrospectively examined. Measures included: 1) daytime and nighttime NIRI use by type (supplemental oxygen therapy via low-flow nasal cannula or positive airway pressure [PAP] via high-flow nasal cannula, continuous positive airway pressure, or biphasic positive airway pressure at admission and discharge) and 2) daytime and nighttime NIRI outcome reduction, increase, or no change from admission to discharge.

RESULTS

For the total sample (n = 38), daytime vs nighttime NIRI use was significantly different (p < 0.001). At both admission and discharge, supplemental oxygen was the most common NIRI during the day, while PAP was most common at night. From admission to discharge, seven (18%) infants and children had a positive change (reduced NIRI) during the day, while nine (24%) had a positive change at night. At discharge, 11/38 (29%) infants and children required no daytime NIRI, while 4/38 (11%) required no day or night NIRI.

CONCLUSION

NIRI use differs between day and night at PACH admission and discharge for CMC. Reductions in NIRI were achieved during the day and at night from PACH admission to discharge for both infants born prematurely and for children with varied congenital, neurological, or cardiac diagnoses.

Children dependent on respiratory support: A 10-year review from one pediatric postacute care hospital

OBJECTIVE

Pediatric postacute care hospitals (PACH) provide long-term care for children with medical complexity including children dependent on respiratory support. Descriptions of PACH respiratory care populations and outcomes, however, remain under-reported. Our aim was to describe demographics, respiratory outcome, and longitudinal trend of children with respiratory support admitted to a single PACH in the United States.

METHODS

Using electronic records from 2009 to 2018, data were examined for all children dependent on respiratory support. Children were identified for inclusion using respiratory level of care classifications (type of support) as outlined in hospital policy. Outcome was defined as change in level from first admission to final discharge. Number of admissions by level and year during the study timeframe were analyzed.

RESULTS

There were 1423 admissions for 767 children requiring respiratory support during the study timeframe. Children with higher respiratory classification level (eg, mechanical ventilation) at initial admission had more admissions to PACH (P < .001) and longer length of stays (P < .001). From first admission to final discharge, there was a significant change (reduction) in respiratory level (z = -4.588, P < .001). An increase in the overall number of admissions for children with respiratory support during the study timeframe was noted, with the largest increase for children requiring the highest level of support.

CONCLUSION

There has been a consistent increase in the number of children requiring respiratory support at admission to PACH. Reduction in respiratory support with postacute care occurs but children admitted with a higher level of support stay longer and experience multiple admissions.

Efficacy and toxicity of pegaspargase and calaspargase pegol in childhood acute lymphoblastic leukemia/lymphoma: Results of DFCI 11-001

10006

Background: DFCI ALL Consortium Protocol 11-001 assessed the efficacy and toxicity of Calaspargase pegol (SC-PEG), a novel pegylated asparaginase (ASP) formulation with longer half-life, compared with standard pegaspargase (SS-PEG). Methods: Patients (pts) aged 1-21 years with newly diagnosed acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LL) were eligible. At study entry, pts were randomly assigned to receive either intravenous SS-PEG or SC-PEG, 2500 IU/m2/dose. Pts received 1 dose during the first treatment month. Beginning week 7, SS-PEG was administered every 2 weeks for 15 doses, SC-PEG every 3 weeks for 10 doses (30 weeks). Serum asparaginase activity (SAA) (considered therapeutic at ≥ 0.1 IU/mL) was assessed 4, 11, 18, and 25 days after the induction dose and before each post-induction dose. End-induction minimal residual disease (MRD) was assessed in ALL pts by IGH/TCR PCR. Results: Between 2012-2015, 239 eligible pts enrolled (230 ALL, 9 LL); 120 assigned to SS-PEG, 119 to SC-PEG. After dose 1, SAA remained ≥ 0.1 IU/mL in ≥ 95% of pts on both arms through day 18. Median SAA was higher (0.319 IU/mL vs 0.056 IU/mL) and more pts had therapeutic SAA (88% vs 17%, p˂0.001) with SC-PEG vs SS-PEG 25 days after dose 1. Post-induction, median nadir SAA (NSAA) were similar ( > 1.0 IU/mL) for both arms. There was no difference in rates of ASP-allergy, pancreatitis, thrombosis, hyperbilirubinemia, osteonecrosis, or infection. Of 230 evaluable pts, 99% of SS-PEG and 95% of SC-PEG pts achieved complete remission (p = 0.12). For B ALL pts, there was no difference in frequency of high end-induction MRD (10.3% SS-PEG, 9.5% SC-PEG, p = 1.0). With 4-year median follow-up, 4-year event-free survival (EFS) (90% confidence interval) for SS-PEG was 90.2% (84.3, 93.9), 87.7% (81.5, 91.9) for SC-PEG (p = 0.78); overall survival (OS) was 95.6% (91.0, 97.9) for SS-PEG, 94.8% (90.0, 97.3) for SC-PEG (p = 0.74). Conclusions: Every 3-week SC-PEG had similar EFS, OS, safety profile, and NSAA compared with every 2-week SS-PEG. The high NSAA observed for both preparations suggest dosing strategies can be further optimized. These data informed FDA approval of SC-PEG for pediatric pts. Clinical trial information: NCT01574274.

Admissions to Acute Care Within 30 and 90 Days of Discharge Home From a Pediatric Post-acute Care Hospital

OBJECTIVES

Of all hospitalized children, those with medical complexity have the highest likelihood of hospital readmission. Post-acute hospital care could potentially help stabilize the health of these children. We examined the frequency of acute care hospital admissions after discharge home from a post-acute care hospital (PACH).

METHODS

A retrospective cohort analysis of 448 children with medical complexity discharged from a PACH from January 1, 2010, to December 31, 2015, with the main outcomes of acute care hospital readmissions 0 to 30 and 31 to 90 days after discharge home from a PACH. Demographic and clinical characteristics were compared between children with and without acute care readmission and between the 2 readmission groups.

RESULTS

Ninety-nine children (22%) had a readmission to the acute care hospital. Of these readmissions, 61 (62%) occurred between 0 and 30 days and 38 (38%) between 31 and 90 days after PACH discharge. A higher percentage of children readmitted had high medical severity (>3 systems involved or ventilator dependent) compared with children not readmitted (68% vs 31%, P = .04). No differences were found between children who were readmitted and those who were not by sex, race, payer, length of stay, or age at PACH discharge. Additionally, no differences were found between children readmitted within 30 days and children readmitted 31 to 90 days after PACH discharge.

CONCLUSIONS

The majority of children discharged home from a PACH do not require an acute care hospitalization within the first 3 months. Children with greater medical severity are readmitted more often than others.

Responsiveness of the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test in measuring functional outcomes for inpatient pediatric rehabilitation

PURPOSE

Responsiveness of the PEDI-CAT Mobility, Daily Activities, and Social/Cognitive domains and Wheelchair subdomain was evaluated for youth admitted to a pediatric post-acute care hospital.

METHODS

Inpatients ages 2-21 years, with a length of stay of ≥ 5 days and with both admission and discharge scores were included. The difference between mean admission and discharge PEDI-CAT scaled scores were analyzed using paired t-tests. Effect sizes, standard response means (SRMs), and minimal detectable change values were calculated. Score comparison between diagnostic subgroups (Traumatic Brain Injury, Neurological, Orthopedic, Medical) and age groups ( ≤ 5, > 5 but < 13, ≥ 13 years) were evaluated for the Mobility domain.

RESULTS

Sample size differed by domain with 66 Mobility, 30 Daily Activities, 19 Social/Cognitive and 9 Wheelchair subdomain pairs. Significant differences were found for all domains when mean admission and discharge scaled scores were compared. Moderate to large effect sizes and SRMs were found for the Mobility and Daily Activities domains and Wheelchair subdomain. Small effect size but large SRM was found for the Social/Cognitive domain. The Mobility domain was also responsive to changes in all diagnostic and age groups.

CONCLUSION

The PEDI-CAT was responsive to functional changes for youth discharged from an inpatient pediatric rehabilitation hospital.

Pediatric Post-Acute Hospital Care: Striving for Identity and Value

The landscape of hospital care for children is changing. Hospital clinicians are challenged to provide high-quality care to 2 increasingly complex groups of children: (1) healthy children admitted for high-severity acute illnesses or injury and (2) children admitted with lifelong, and often disabling, chronic conditions. Hospitalizations for both of these groups are becoming more prevalent, lengthy, and costly. In many situations, these children need weeks, or sometimes months, to recover from their illness or injury, with a sustained intensity of daily caregiving needs throughout their recovery period. Pediatric post-acute hospital care is a little-known and underused option in pediatric health care that could substantially help these children stabilize in a less restrictive and less costly environment than acute care hospitals can provide. In this commentary, we (1) propose the need and place for pediatric post-acute care hospitals along the continuum of care, (2) discuss the characteristics of children currently cared for in pediatric post-acute care hospitals, (3) suggest research opportunities and challenges, and (4) present issues related to the cost and value of pediatric post-acute care hospitals.

Unplanned readmissions to acute care from a pediatric postacute care hospital: incidence, clinical reasons, and predictive factors

OBJECTIVE

To identify the incidence, clinical reasons, and predictive factors for unplanned readmissions to acute care from a pediatric postacute care hospital.

METHODS

A retrospective cohort analysis of all discharges between October 1, 2011, and September 30, 2013 (n=298), in 1 pediatric postacute care hospital was conducted. Descriptive statistics were used to summarize the incidence and assess the clinical reasons for all readmissions to an acute care hospital. Logistic regression was used to identify predictive factors of any unplanned readmission to an acute care hospital.

RESULTS

Thirty percent of all postacute care hospital discharges were unplanned readmissions to an acute care hospital. The primary clinical reasons for unplanned readmissions to acute care were respiratory decompensation (54%) and infection (20%). Requiring invasive mechanical ventilation, being <1 year of age, and having a postacute care length of stay<30 days were the 3 predictive factors.

CONCLUSIONS

This is the first study to examine readmission to acute care from a postacute care hospital and to identify age, length of stay, and dependence on mechanical ventilation as predictive factors. Understanding which children are likely to require an unplanned readmission may allow providers to develop strategies to minimize this occurrence.

Neonatal abstinence outcomes in post-acute care: A brief report

PURPOSE

To describe characteristics and care outcomes in a pediatric post-acute rehabilitation hospital for infants with Neonatal Abstinence Syndrome (NAS).

METHODS

Demographic and clinical data were combined for 43 infants accounting for 46 admissions over a two-year period with a diagnosis of NAS and a goal of weaning from treatment medications.

RESULTS

Mean age at admission for the total sample was 21 days. One hundred percent of the infants were weaned from treatment medications at discharge and all infants were discharged to a home setting. Mean length of stay in post-acute care was 24 days (SD = 12.80; range = 4-70 days) while the mean cost of admissions was $27,904. Ninety-one percent had a public payer. Post-acute care clinical outcomes were excellent.

CONCLUSION

Post-acute care for infants with NAS could be an effective way to free NICU beds and reduce hospital costs for this population of infants.

Pediatric post-acute care hospital transitions: an evaluation of current practice

OBJECTIVES

After discharge from an acute care hospital, some children require ongoing care at a post-acute care hospital. Care transitions occur at both admission to the post-acute care hospital and again at discharge to the home/community. Our objective was to report the current practices used during the admission to and discharge from 7 pediatric post-acute care hospitals in the United States.

METHODS

Participants from 7 pediatric post-acute care hospitals completed a survey and rated the frequency of use of 20 practices to prepare and support children and their families during both admission to the hospital and at time of discharge to the home/community. For consistency with existing literature, practices were grouped into 4 previously reported categories: assessment, communication, education, and logistics. Descriptive statistics were used to report the frequency of use within practices and between hospitals.

RESULTS

Only 2 of 10 admission practices and 3 of 10 discharge practices were reportedly "always" used by all hospitals. Assessment and communication practices were reported to be more frequently used (57%-100% of the time) than education and logistic procedures. Between hospitals, only the reported frequency of use of the discharge practices was statistically significantly different (P = .03).

CONCLUSIONS

Variability exists in transition practices among 7 post-acute care pediatric hospitals. This report is the first known to detail the frequency of use of admission and discharge practices for pediatric post-acute care hospitals in the United States.

Hospital length of stay, discharge disposition, and reimbursement by clinical program group in pediatric post-acute rehabilitation

OBJECTIVE

To describe hospital length of stay (LOS), discharge disposition, and reimbursement by clinical group for children admitted to pediatric post-acute rehabilitation.

METHODS

Demographic and financial information for all admissions (n=382) for calendar years 2010 and 2011 were combined. Clinical groups (Active Rehabilitation, Medically Complex, Ventilator Dependent, Neonates) were delineated and compared by LOS, discharge disposition, and per diem and per admission reimbursement, as well as by age, gender, admission number, and payer using descriptives, chi-square, or analysis of variance. LOS, discharge disposition, and reimbursement were also examined by payer and/or admission number.

RESULTS

Clinical groups differed by LOS (p=0.008), discharge disposition (p < 0.001), age (p < 0.001), admission number (p < 0.001), and payer (p < 0.001). Although per diem reimbursement was not statistically significant between groups, total admission reimbursement was highest for the Ventilator group due to a significantly longer LOS (mean=57.78 days, SD=56.33, p=0.008). LOS nor discharge disposition was significantly different if the payer was public or private. Children were more likely discharged home from a first admission (r=0.321, p < 0.001) than a subsequent admission, and private payers had a significantly greater (p< 0.001) mean daily reimbursement rate.

CONCLUSION

Hospital LOS, discharge disposition, and reimbursement vary by clinical group in pediatric post-acute rehabilitation.

Measuring physical function in children with airway support: a pilot study using computer adaptive testing

OBJECTIVE

To assess the responsiveness, examine the scoring range and determine the efficiency of a multidimensional computer adaptive testing version of the Pediatric Evaluation of Disability Inventory (PEDI-MCAT) for children admitted to inpatient pulmonary rehabilitation.

METHODS

The PEDI-MCAT was completed by clinician report for 30 infants and children. Mean self-care and mobility admission scores were compared with discharge scores for the total group and two diagnostic sub-groups (prematurity and congenital/neurological conditions). The scoring range of the mobility and self-care scales was examined to determine placement of the scores along the overall PEDI-MCAT scale. Efficiency was determined using an internal clock and average number of items required for score generation.

RESULTS

Mean changes for the total group and both sub-groups were significant for both self-care and mobility, except for the prematurity group's mobility scores. Effect sizes were small-to-moderate. Scores for both groups were at the low end of the scoring ranges. Average time to complete the PEDI-MCAT was 1.57 minutes. Average number of items administered was nine for self-care and 11 for mobility.

CONCLUSION

The PEDI-MCAT was responsive to change in physical function, although only low-ability items were needed. The PEDI-MCAT can potentially minimize clinician burden in inpatient settings.

Weaning children from mechanical ventilation in a post-acute care setting

As medical and technological advances have made it possible to prolong the life of children with chronic respiratory failure, children are being referred to post-acute inpatient rehabilitation programmes. In these settings, children can be weaned from their ventilators and receive medical and rehabilitative care in a developmentally supportive environment at a lower financial cost than in an intensive care unit. There is strong evidence that weaning children from mechanical ventilation has beneficial effects on their functionality, ease of care and quality of life. There is, however, little scientific evidence describing how often successful weaning is achieved or the most effective methods. The purpose of this article is to present a consensus report detailing a structured approach to weaning children from mechanical ventilation in a post-acute care setting. This study proposes a Weaning Severity Index and a Weaning Algorithm for use in the assessment and implementation of the weaning process in post-acute rehabilitation. Future clinical studies are needed to validate the suggested approach to ventilator weaning and to determine whether or not the weaning algorithm results in beneficial patient outcomes.

Development and evaluation of a minimum data set for children with airway support for transfers between acute and post-acute care

OBJECTIVE

To generate consensus on the reasons why children with airway support transfer between acute and post-acute care; develop a minimum data set to transmit between care settings; and examine transfer reports to determine the frequency of data set content.

STUDY DESIGN

Two consensus development meetings were conducted of acute and post-acute care professionals to identify reasons for transfer and develop the minimum data set. A content analysis was used to generate the frequency of inclusion of minimum data set elements in the narrative reports of 15 acute to post-acute and 15 post-acute to acute transfer summaries. The observed frequencies were compared with the expected frequencies (95%), as were frequencies between the two groups.

RESULTS

Advanced diagnostic assessment and unexpected changes in medical, surgical and mental health conditions were the primary reasons for transfer from post-acute to acute care. For transfers in both directions, 20 of the 34 data elements were present in <75% of the cases and were statistically different than the pre-set 95% standard. No statistical difference in the occurrence of data elements between transfer directions existed.

CONCLUSION

A minimum data set has the potential to reduce redundancy, improve safety and optimize care co-ordination between facilities for children with airway support.

Bronchoscopy findings in children and young adults with tracheostomy due to congenital anomalies and neurological impairment

The aim of this study was to examine bronchoscopy findings for children and young adults with long-term tracheostomies due to congenital anomalies and neurological impairment and identify characteristics associated with abnormal bronchoscopic findings. We conducted a retrospective study of 128 bronchoscopy cases (81 children) at a pediatric rehabilitation center. Thirty-eight cases (30%) had normal findings and 14 children (17% of all children) were decannulated following bronchoscopy. Ninety cases (70% of cases) had abnormal findings (e.g. granulomas, airway inflammation, fixed obstruction). An acute indication for bronchoscopy was the strongest predictor of an abnormal finding, while age (younger) and diagnosis (multiple congenital anomalies (MCA)) also were associated with abnormalities. For a subsample of children undergoing bronchoscopy for routine surveillance (n= 90), underlying diagnosis (MCA) was the strongest predictor of an abnormal finding, while younger age contributed slightly. These findings add to the limited literature describing bronchoscopic findings in children and youth with tracheostomies due to congenital anomalies or neurological impairment. These findings may be useful for rehabilitation clinicians in determining care needs for children with long-term tracheostomy.

Outcomes of post-acute hospital episodes for young children requiring airway support

In this descriptive study, we examined changes in invasive and non-invasive airway support; studied the rates of home discharge vs. long-term care or acute hospitalization; and examined the relationship between the level of airway support and discharge to home for 92 children (<3 years of age) with 104 admission-discharge episodes to a consortium of pediatric rehabilitation hospitals over a one-year period. We found a significant reduction (p < 0.001) in the level of airway support between admission and discharge. In 21 of 47 (45%) episodes, children weaned from mechanical ventilation to a less restrictive type of support. Sixty percent of the children had final discharges to home. There was a significant, though fair correlation (Spearman Rho = -0.344, p = 0.001) between home discharge and level of airway support. These outcomes data provide a multi-site baseline for understanding expected changes in airway support and home discharge rates of young children who are admitted to a post-acute inpatient program.

Ventilator weaning outcomes in chronic respiratory failure in children

The purpose of this study was to describe mechanical ventilation weaning outcomes for children with chronic respiratory failure discharged from one of six post-acute rehabilitation facilities. Demographic, clinical and outcome data were collected from the medical record. Forty-four children were included in this prospective series; 20 (45%) were weaned off the ventilator at discharge. Children required significantly lower levels of ventilatory support at discharge than admission. Hourly use on the ventilator decreased from admission to discharge for the full cohort and for the subgroup who required a ventilator at discharge. Seventy-five percent of the children discharged with a ventilator had a portable unit. We conclude that nearly half of the children using mechanical ventilation achieve weaning during a postacute rehabilitation admission, whereas others have positive outcomes in severity, hours off the ventilator or portability of equipment.

Congenital neurodevelopmental diagnoses and an intensive care unit: defining a population

OBJECTIVE

To identify and describe the population of children with congenital or perinatally acquired neurodevelopmental diagnoses in a pediatric intensive care unit and to assess the nature and extent of their utilization of critical care resources.

DESIGN

Twelve-month, inception cohort study.

SETTING

Intensive care unit at an urban, tertiary care pediatric hospital.

PATIENTS AND METHODS

All pediatric intensive care unit admissions were screened for preexisting neurodevelopmental diagnoses. Computerized and chart-based medical records were reviewed for demographic, clinical, and outcome data.

RESULTS

A total of 309 children with congenital neurodevelopmental diagnoses accounted for 427 pediatric intensive care unit admissions. This represented 23% of the total 1,820 admissions in 1 yr. Trisomy 21 was the most identifiable developmental abnormality (n = 25, 8%). Eighty-five percent of the children were cared for at home before hospitalization. A total of 220 of the admissions (52%) demonstrated a preexisting technology dependence. Fewer children admitted from the home-care setting had tracheostomies or were ventilator dependent. The majority of admissions were scheduled surgical admissions (45%) or for management of acute respiratory illness (26%). Of the patients with preexisting tracheostomy, nonrespiratory conditions accounted for 70% of acute admitting diagnoses. Two hundred twenty-three of the admissions (52%) required noninvasive or transtracheal ventilatory support, yet the length of stay and mortality rate were consistent with those reported in other general pediatric intensive care unit populations. The average and median length of stay were 5.4 and 2.0 days, respectively. Mortality rate was 3%. Technology support needs at discharge increased significantly from admission for enterostomy support (p =.008) and mechanical ventilation (p =.008).

CONCLUSIONS

Children with congenital or perinatally acquired neurodevelopmental diagnoses represented nearly one quarter of all pediatric intensive care unit admissions at a tertiary academic center. This population has substantial ongoing medical needs, requiring utilization of intensive care resources. More rigorous investigations are needed to determine the effect of this burgeoning population in pediatric critical care, to optimize their care, and to meet the comprehensive needs of their families.

Oxygen and ventilator weaning during inpatient pediatric pulmonary rehabilitation

Rates of oxygen and ventilator weaning, and factors related to successful weaning in inpatient pediatric pulmonary programs for infants and young children, have not been frequently reported in the literature. A retrospective review was conducted of 34 infants and toddlers with either a diagnostic condition of prematurity (PM) or congenital anomalies/neuromuscular disease (CA/NM) discharged from an inpatient pulmonary program. These cases represent 67 hospital admission-discharge episodes over a 6-year period. The rate of successful oxygen weaning (decrease to 0 hr per day) and ventilator weaning (decrease to <12 hr per day) and predictive factors related to successful ventilator weaning per admission-discharge episode were examined. Successful oxygen weaning was achieved during 24% and successful ventilator weaning was achieved during 30% of the admission-discharge episodes. No significant relationships were found between the selected demographic and clinical factors and oxygen weaning. Using a logistic regression model, the major variable associated with successful ventilator weaning per admission-discharge episode was diagnostic condition. Age at admission and the presence of comorbidities added slightly to the prediction model. The overall model yielded 86% accuracy for predicting a decrease in ventilator hours. However, projecting in which episodes children will not be weaned (negative predictive value = 88.9%) was more accurate than projecting in which episodes children will be weaned (positive predictive value = 73.3%). Although the program achieved a relatively low rate of successful ventilator weaning, children with a diagnostic condition of prematurity were more likely to be successfully weaned during inpatient pulmonary rehabilitation.

Re-admissions to inpatient paediatric pulmonary rehabilitation

OBJECTIVE

To describe re-admission rates, identify reasons for re-admission and examine characteristics of children requiring re-admission to inpatient pulmonary rehabilitation.

METHODOLOGY

Retrospective record review of infants and toddlers (less than three years of age) requiring oxygen or ventilator support discharged from an inpatient paediatric pulmonary rehabilitation programme between 1992 and 1999.

RESULTS

Forty-one initial admissions resulted in 45 readmissions with a mean re-admission rate of 1.1 (SD = 1.41) re-admissions per child. Children with re-admissions (n = 22, 54%) required significantly more ventilator support (p = 0.001) and nursing care (p = 0.001) and were transferred to acute care more frequently (p = 0.002) than children without re-admissions. One-half of the children re-admitted to inpatient pulmonary rehabilitation were re-admitted two or more times.

CONCLUSIONS

Based on this cohort of children, dependence on supplemental oxygen and/or mechanical ventilation and medical complexity may be indicators that children will require re-admission to rehabilitation following a transfer back to acute care. Further examination of re-admission rates and reasons and children's clinical characteristics may have predictive value and provide practice improvement opportunities.

Clinical findings and resource use of infants and toddlers dependent on oxygen and ventilators

Medical records were reviewed to describe characteristics, report clinical and resource measures, and determine if differences exist between the diagnostic groups of prematurity and multiple congenital anomalies/neurologic conditions for initial admissions of 37 infants and toddlers to an inpatient pulmonary rehabilitation program. More than 75% of the children had a tracheostomy at admission and discharge. Forty-six percent of the sample was admitted requiring only oxygen, whereas 51% were discharged requiring only oxygen and not mechanical ventilation. Thirty percent of the children weaned to a less invasive mode of ventilation while just under half of the children were discharged home. Between-group comparisons indicated statistically significant differences for nutritional support at discharge (p < or = 0.05) and discharge disposition (p = 0.04). Complete weaning of oxygen or ventilator support during an initial inpatient pulmonary rehabilitation admission occurred less frequently than weaning to a less invasive mode of ventilation. This is an important consideration for referring children to rehabilitation programs, for clinical program improvement activities, and for setting realistic expectations for referral sources, patients and families, clinical staff, and payers. Further study is recommended using clinical data in program planning, in program improvements, and for setting outcome expectations for infants and toddlers dependent on pulmonary technology.

Second-trimester biochemical screening

The past years have seen considerable progress in the area of biochemical screening. Increasing data have now clearly shown the advantages of multiple markers, particularly beta-hCG over AFP alone. There continues to be considerable controversy over the best mathematic algorithm and which markers are best (e.g., beta-HCG, uE3, and so forth). There seems to be a plateau of detection frequencies at about 65% to 70% with current methodologies. Further work needs to be done, however, including some new approaches, if there is to be substantial improvement of screening sensitivity. The combination of biochemical with biophysical parameters as discussed elsewhere in this issue represents the next level of sophistication in the attempt to identify the highest proportion of abnormalities with the fewest false-positives.

VAM-1: a new member of the MAGUK family binds to human Veli-1 through a conserved domain

The MAGUKs (membrane-associated guanylate kinase homologues) constitute a family of peripheral membrane proteins that function in tumor suppression and receptor clustering by forming multiprotein complexes containing distinct sets of transmembrane, cytoskeletal, and cytoplasmic signaling proteins. Here, we report the characterization of the human vam-1 gene that encodes a novel member of the p55 subfamily of MAGUKs. The complete cDNA sequence of VAM-1, tissue distribution of its mRNA, genomic structure, chromosomal localization, and Veli-1 binding properties are presented. The vam-1 gene is composed of 12 exons and spans approx. 115 kb. By fluorescence in situ hybridization the vam-1 gene was localized to 7p15-21, a chromosome region frequently disrupted in some human cancers. VAM-1 mRNA was abundant in human testis, brain, and kidney with lower levels detectable in other tissues. The primary structure of VAM-1, predicted from cDNA sequencing, consists of 540 amino acids including a single PDZ domain near the N-terminus, a central SH3 domain, and a C-terminal GUK (guanylate kinase-like) domain. Sequence alignment, heterologous transfection, GST pull-down experiments, and blot overlay assays revealed a conserved domain in VAM-1 that binds to Veli-1, the human homologue of the LIN-7 adaptor protein in Caenorhabditis. LIN-7 is known to play an essential role in the basolateral localization of the LET-23 tyrosine kinase receptor, by linking the receptor to LIN-2 and LIN-10 proteins. Our results therefore suggest that VAM-1 may function by promoting the assembly of a Veli-1 containing protein complex in neuronal as well as epithelial cells.

Outcome following tricuspid valve detachment for ventricular septal defects closure

OBJECTIVES

Detachment of the septal leaflet of the tricuspid valve from the annulus (TVD) has been used to improve visualization of ventricular septal defects (VSDs), but may be associated with increased operative time, heart block, and the development of tricuspid regurgitation (TR).

METHODS

Patients undergoing VSD closure between 1/1/96 and 31/12/99 were retrospectively reviewed. Follow-up was obtained from the patients' cardiologists.

RESULTS

Transatrial VSD closure was performed in 172 patients with TVD in 36 (21%) at the surgeon's discretion. The leaflet incision was repaired with a separate suture (22) or with the VSD patch suture (14). Additional procedures including arch augmentation, closure of atrial septal defects, and closure of additional VSDs were performed in 93 (68%) non-TVD patients and 20 (56%) TVD patients. The median age was 6.2 months (range 1 day to 46 years) and the median weight was 5.9 kg (range 1.5-71.5 kg). Cardiopulmonary bypass (CPB) time was 64+/-24 min and cross-clamp time was 34+/-16 min. One hospital death occurred in an infant with tracheal stenosis. No child in either group developed complete heart block. The median duration of postoperative stay was 4 days (range 2-49 days). There were no differences in CPB time, cross-clamp time or postoperative stay between the TVD and non-TVD groups (P>0.1 for all). At a mean follow-up of 17+/-15 months, there have been two late deaths unrelated to cardiac disease. No child in the TVD group required reoperation for residual VSD, compared to three in the non-TVD group. No child in the TVD group has greater than mild TR, but six in the non-TVD group have greater than mild TR. No child in either group has undergone reoperation for TR.

CONCLUSIONS

TVD is a safe, effective technique to improve visualization of VSD and is not associated with heart block, increased operative time, or TR. TVD may result in improved preservation of tricuspid valve architecture and decrease the incidence of significant postoperative TR.

Second-trimester maternal serum marker screening: maternal serum alpha-fetoprotein, beta-human chorionic gonadotropin, estriol, and their various combinations as predictors of pregnancy outcome

OBJECTIVE

We evaluated the value of all 3 common biochemical serum markers, maternal serum alpha-fetoprotein, beta-human chorionic gonadotropin, and unconjugated estriol, and combinations thereof as predictors of pregnancy outcome.

STUDY DESIGN

A total of 60,040 patients underwent maternal serum screening. All patients had maternal serum alpha-fetoprotein measurements; beta-human chorionic gonadotropin was measured in 45,565 patients, and 24,504 patients had determination of all 3 markers, including unconjugated estriol. The incidences of various pregnancy outcomes were evaluated according to the serum marker levels by using clinically applied cutoff points.

RESULTS

In confirmation of previous observations, increased maternal serum alpha-fetoprotein levels (>2.5 multiples of the median) were found to be significantly associated with pregnancy-induced hypertension, miscarriage, preterm delivery, intrauterine growth restriction, intrauterine fetal death, oligohydramnios, and abruptio placentae. Increased beta-human chorionic gonadotropin levels (>2.5 multiples of the median [MoM]) were significantly associated with pregnancy-induced hypertension, miscarriage, preterm delivery, and intrauterine fetal death. Finally, decreased unconjugated estriol levels (<0.5 MoM) were found to be significantly associated with pregnancy-induced hypertension, miscarriage, intrauterine growth restriction, and intrauterine fetal death. As with increased second-trimester maternal serum alpha-fetoprotein levels, increased serum beta-human chorionic gonadotropin and low unconjugated estriol levels are significantly associated with adverse pregnancy outcomes. These are most likely attributed to placental dysfunction.

CONCLUSION

Multiple-marker screening can be used not only for the detection of fetal anomalies and aneu-ploidy but also for detection of high-risk pregnancies.

Distribution of neural tube defects as a function of maternal weight: no apparent correlation

OBJECTIVES

Maternal nutritional deficiency is an important predisposing factor to congenital neural tube defects (NTDs). It was hypothesized that obese women may have an increased risk for NTDs. The aim of the present study was to address this question in a large cohort.

METHODS

A total of 72,915 consecutive cases of biochemical screening that had documented maternal weights and pregnancy outcomes were identified from the Quest Diagnostic Laboratories database. Patients were divided into five ranges of maternal weights, and the incidence of NTDs was calculated for each group. Based on the different definitions of maternal overweight, the data were also analyzed based on 2 groups only, obese and nonobese, using three cutoff points.

RESULTS

Seventy-nine pregnancies were complicated by NTDs (incidence of 1.08 per 1,000 pregnancies). Differences between maternal weights ranges were not found to be statistically significant (chi2 = 5.997, p = 0.19, power = 0.99). Differences between obese and nonobese mothers were not found to be statistically significant for all three analyses as well.

CONCLUSIONS

Our present results do not support an association between maternal obesity and NTDs.

Screening for aneuploidy

Over the past 15 years, biochemical screening for chromosomal abnormalities, particularly Down's syndrome, has advanced from being extremely naive, to now somewhat more sophisticated. Sensitivities have gone from 20% to 60-70%. Considerable work is still required to not only increase the sensitivity, but also the specificity to keep health care costs down.

Variability of adjustments to indices in determining patient risk in biochemical screening

It has long been appreciated that the measurement of biochemical parameters for prenatal screening for neural tube defects, and later aneuploidy, is not as simple as measuring hemoglobin or hematocrit. Early in the game, it was recognized that there are gestational age curves, and that since alpha-fetoprotein (AFP), for example, is a fetal product, its distribution varies as a function of maternal plasma volume, and therefore the weight of the mother. A number of different adjustment factors have been used for AFP and other parameters for years, with varying degrees of consistency and reliability. Here we review a number of adjustments that have been used, and try to give priority to those that have been most effective. Furthermore, laboratories and programs need to be cognizant that with newer parameters being added, the specifics of requirements will vary on a case-by-case parameter basis, and optimal screening can only be achieved with the appropriate adjustments.

Determination of reference values for a novel ketoamine-specific fructosamine assay for assessment of diabetic glycemic control

BACKGROUND

Intensive monitoring to improve glycemic control is essential for effective management of diabetes and reduction of long-term morbidity and pathology. Measurement of glycated serum proteins (fructosamine) allows more frequent assessment (monthly) of glycemic control than the 2- to 3-month window of the traditional glycated hemoglobin (HbA1c) assay. In response to concerns about assays designed to measure glycated serum proteins based on the nitroblue tetrazolium (NBT) methodology, a novel assay to measure glycated serum proteins has been developed based on the specific oxidation of the ketoamine bonds within the glycated proteins.

METHODS

Reference range values for this new, enzymatic glycated-serum-protein assay (GlyPro; Genzyme Corporation, Cambridge, MA) are reported.

RESULTS

The GlyPro reference range is lower and shows close correlation with ranges reported for the NBT assay. The 95% overall reference range was 122 to 236 mumol/L.

CONCLUSIONS

GlyPro is a reliable, accurate assay and correlates well with the NBT assay for the measurement of glycated serum proteins. The assay may be useful in the short-term assessment of diabetes control, a necessary complement to long-term control as assessed by hemoglobin A1c (HbA1c) assays.

Simple preparation of the major urinary metabolites of flunitrazepam and nitrazepam

An alarming increase in the misuse/abuse of nitrobenzodiazepine derivatives, especially flunitrazepam, prompted us to establish reliable analytical protocols for their routine detection. Whilst the parent drugs are readily available from a number of commercial sources, it was found difficult to obtain samples of the corresponding amino metabolites which were required as analytical standards. This lead us to develop the straightforward synthetic protocol described here, to convert the readily available parent drugs, namely flunitrazepam and nitrazepam, to their respective 7-amino derivatives. The method requires minimum laboratory facilities. It involves the reduction of the nitro functionality in the parent drug to an amino group using tin (II) chloride under mild conditions, using ultrasonication at room temperature. The method is simple and should give toxicology laboratories better access to these much needed compounds.

Sustained reduction of neointima with c-myc antisense oligonucleotides in saphenous vein grafts

BACKGROUND

Treatment of saphenous veins with c-myc antisense oligomers during preparation for grafting reduces medial cellular proliferation and macrophage infiltration, and preserves medial smooth muscle content at 3 days. Accordingly, the purpose of this study was to examine whether c-myc antisense oligomers have an impact on late vein graft remodeling.

METHODS

Sixty-two pigs underwent unilateral saphenous vein-carotid artery interposition grafting. Harvested veins were incubated either in saline (control group) or 20-micromol/L or 200-micromol/L concentrations of c-myc antisense oligomers (treated groups) for 30 minutes intraoperatively. Three months after surgery, vein graft histology was assessed.

RESULTS

Forty-five of 62 randomized animals survived the experiment; no differences in animal survival or graft patency among the groups were observed (p = NS, chi2). C-myc antisense oligomers significantly decreased neointimal and wall thickness, as well as increased lumenal index, in treated groups (p<0.04, p<0.03, and p<0.001, respectively, analysis of variance). In contrast, there was no difference in medial thickness or perivascular wound healing.

CONCLUSION

Intraoperative treatment of saphenous veins with c-myc antisense oligomers decreased neointimal formation at 3 months after grafting. In conjunction with our previous reports, these findings suggest that early inhibition of cellular proliferation and inflammatory infiltration results in a sustained reduction in neointimal formation and favorable graft remodeling.

Age-specific variation in aneuploidy incidence among biochemical screening programs

OBJECTIVE

Our purpose was to compare the observed age-related incidence of Down syndrome in two large screening programs with the commonly quoted incidences used in biochemical screening programs.

STUDY DESIGN

Data from two large prenatal screening programs were stratified in 5-year age groups. The age-related incidence of Down syndrome was compared with the commonly used incidence as reported by Cuckle.

RESULTS

No significant differences were found in age-related incidences of Down syndrome in any age group between the screening groups or among women ages 15 through 29 in any of the three groups. However, for women 30 to 34 and > or = 40 years old, a trend was noted toward a higher incidence in the screening groups. For women ages 35 to 39, the observed incidence was significantly greater in the screening groups compared with the data of Cuckle.

CONCLUSION

Our data suggest an underascertainment in Down syndrome risk built into the Cuckle model, particularly in high-risk patients.

Detection of anomalies: alternatives to ultrasound

Ultrasound and biochemical screening are complementary screening tests that each have limitations and advantages. The next several years will see variable progress in the evolution of these techniques, which, it is hoped, will result in an appropriate role for each to achieve a cost-effective, highly sensitive and specific screening approach that will allow couples the most comfort in detecting problems during pregnancy, as well as a high degree of confidence that normal results are accurate.

Early injury to the media after saphenous vein grafting

BACKGROUND

Injury to the smooth muscle cells of the media affects the remodeling process of vein grafts. The purpose of this study was to determine whether different techniques of surgical preparation influence the degree of medial smooth muscle injury.

METHODS

Carotid-saphenous vein interposition grafting was performed in crossbred pigs (n = 32), using distended (n = 16) or nondistended (n = 16) conduits. After 3 to 90 days, the media was evaluated for the presence of smooth muscle cells (desmin stains), myofibroblast formation (transient alpha-SM actin expression), and apoptosis (TdT-mediated dUTP nick end-labeling [TUNEL]).

RESULTS

Smooth muscle loss was uniformly severe; only 5% +/- 5% (p < 0.01) and 14% +/- 9% (p < 0.01) of the medial area of distended and nondistended veins were desmin positive in comparison with 80% +/- 9% of controls. Apoptosis appeared to contribute to medial smooth muscle loss (5.7% +/- 4.3% in vein grafts versus 0.0% +/- 0.0% of TUNEL-positive cells in controls; p = 0.05). There was a time dependent increase in medial myofibroblast formation (p < 0.05).

CONCLUSIONS

Severe medial smooth muscle loss occurs in vein grafts, even when prepared without distension. Apoptosis contributes to the early disappearance of smooth muscle cells. Adjunctive measures, in addition to ideal surgical techniques, should be developed to prevent medial muscle loss.

Fetal gender impact on multiple-marker screening results

Maternal serum alpha-fetoprotein (MSAFP), human chorionic gonadotropin (hCG), and unconjugated estriol (uE3) are used in combination with maternal age to calculate the risk for Down syndrome (DS) in pregnancy. Increased levels of hCG and decreased levels of MSAFP and uE3 are consistent with an increased risk for DS. We retrospectively evaluated second-trimester maternal serum marker levels in a large cohort of patients with known normal outcomes and documented fetal gender. These included 15,428 patients who had MSAFP measurements, 11,428 patients with both MSAFP and hCG, and 6,090 patients with all three markers including uE3. MSAFP levels in patients with female fetuses were consistently lower than those with males. Conversely, hCG was higher in pregnancies with females as compared to males. No gender-related difference was noted for uE3. These results would suggest that the computed DS risk for female fetuses is higher than for males, despite the fact that the incidence of DS is similar in both genders. This information could be useful for calculating gender-specific DS risk; however, this would require ultrasonographic determination of fetal sex.

Combination of elevated maternal serum alpha-fetoprotein (MSAFP) and low estriol is highly predictive of anencephaly

Increased levels of second trimester maternal serum alpha-fetoprotein (MSAFP) have long been established as a marker for neural tube defects (NTDs). In addition, decreased levels of maternal estriol in the third trimester have been reported in pregnancies with anencephalic fetuses. The purpose of this study was to evaluate whether early second trimester unconjugated serum estriol (uE3) is an independent predictor of NTDs. The study included 57,031 patients who underwent maternal serum screening with MSAFP at 14-22 weeks gestation. Of these, 23,415 also had uE3 measurements. There were 63 cases of NTD, an overall incidence of 1.1 per 1,000. Elevated MSAFP (> or =2.5 MOM) was detected in 1,346 patients, 48 of which had NTDs. Decreased uE3 (< or =0.5) was detected in 1,437 patients, 17 of which had NTDs. The incidence of NTDs was significantly higher in patients with low uE3, compared to patients with normal/high uE3 (1.15% vs. 0.09%, P < 001). Finally, 51 patients had both increased MSAFP and decreased uE3; 16 of these had NTDs, 14 of which were anencephalics. In conclusion, both elevated MSAFP and low maternal serum estriol are predictive of NTD but have a low sensitivity. The combination of abnormally elevated MSAFP and low estriol is highly predictive of NTD in particular anencephaly.

Effect of adjustment of maternal serum alpha-fetoprotein levels in insulin-dependent diabetes mellitus

Our objective was to determine the effect of the 20% upward adjustment of maternal serum alphafetoprotein (MSAFP) in patients with insulin-dependent diabetes mellitus (IDDM) on the number of patients that would be classified at increased risk for pregnancy complicated by either Down syndrome (DS) or neural tube defect (NTD). We retrospectively evaluated a database containing 63,110 patients who underwent multiple serum marker screening between 14 and 22 weeks gestation; 620 patients with IDDM had measurements of MSAFP of which 479 also had measurements of beta-HCG, allowing calculation of DS risk. Increased NTD risk was defined as MSAFP >2.5 MOM while increased DS risk was defined as a calculated risk > or =1/270. One IDDM patient delivered an infant with a NTD; it was not detected on serum screening. No infants were born with DS. Of the 620 patients with MSAFP determinations, 9 had values >2.5 MOM before adjustment. After upward adjustment, 7 additional patients were identified. Sixteen patients were identified at increased risk for DS before and after adjustment. Our data suggest that the 20% upward adjustment of MSAFP increases by 78%, the number of patients who would require further evaluation for NTD's. Although we were able to identify 620 women with IDDM who underwent serum screening for NTD, the low prevalence of NTD's did not allow us to demonstrate an increased detection rate. The effect of upward adjustment of MSAFP on the number of patients categorized at increased DS risk appears to be minimal.

Saphenous vein graft protection: effects of c-myc antisense

OBJECTIVE

Saphenous vein grafting is associated with extensive medial remodeling, characterized by cellular proliferation, loss of smooth muscle cells, and an inflammatory response. In this study, we examined whether unfavorable responses to vein grafting could be modified by the intraoperative application of c-myc antisense oligomers.

METHODS

The intragraft cell proliferation, macrophage infiltration, and medial preservation were examined in a porcine model in the control and antisense-treated groups (n = 36).

RESULTS

Saphenous veins showed transmural distribution of oligomers within 30 minutes of the ex vivo incubation. A concentration-dependent inhibition of cell proliferation in the media of saphenous grafts was noted 3 days later (0 to 200 mumol/L, p = 0.005). The growth inhibition was sequence-specific, because control oligomers produced only insignificant effects (20 mumol/L). Vascular effects of c-myc antisense were associated with a significant attenuation of macrophage infiltration in saphenous grafts. A concentration-dependent decrease in tissue edema (p = 0.0005) and the attenuated loss of smooth muscle cells (p = 0.002) were noted in the media of the arterialized venous conduits after c-myc antisense.

CONCLUSIONS

Direct application of synthetic DNA to harvested saphenous veins resulted in a rapid transmural distribution. The inhibition of the intragraft cell proliferation in vivo after c-myc antisense was sequence dependent. Decrease in vein graft injury resulted in an attenuated inflammatory response and better medial preservation. These findings provide a rationale for assessment of the long-term effects of vein graft protection with c-myc antisense.

Maternal weight differences do not explain ethnic differences in biochemical screening

In previous work, we and others have shown that serum levels of alpha-fetoprotein, human chorionic gonadotropin, and estriol vary among the four commonly defined racial/ethnic groups seen in the United States: white, African-American, Asian, and Hispanic. We have suggested that better sensitivity and specificity could improve screening sensitivity and specificity. However, it has been argued that systematic weight differences among the groups could explain the variation. We evaluated the results from 208,257 patients having screening and found systematic weight differences. However, these differences were not as large as the racial/ethnic differences, showing that weight does not fully explain the discrepancy, and, therefore, four separate data bases give more accurate results.

Differential increases in AFP, hCG, and uE3 in twin pregnancies: impact on attempts to quantify Down syndrome screening calculations

Since the advent of multiple marker screening (MMS) for Down syndrome (DS) risk calculations, limitations for twins have been apparent. Recent attempts have been made to extrapolate mathematically singleton risks to twins. Here we investigate the pattern of levels among AFP, hCG, and uE3 in twins. MMS screening data from 4,443 twin pregnancies were compared to those from 258,885 singletons from 14-21 weeks of gestational age during a 3-year period (1992-1994) in our laboratory. Medians were determined for singletons and twins, and the ratios of twins to singletons were derived. Median AFP levels for twins are approximately double those of singletons, but median increases for hCG and uE3 are less than double. The data were divided further by ethnic groups (white, African American, Asian, and Hispanic), among which there were significant variations in medians, but not in the ratios of twins to singletons. The increased serum levels of different markers in twins are not consistent across analytes, possibly reflecting independent development of different compartments. Such differences mean that a mere mathematical conversion of singleton DS risks would be imbalanced among the analytes and cannot be applied reasonably to twins. Ethnic-specific databases are as important in twins as they are in singletons.

Comparison of teaching the basic electrocardiographic concept of frontal plane QRS axis using the classical versus the orderly electrocardiogram limb lead displays

This study compares the effectiveness of teaching the calculation of frontal plane QRS axis with the use of the classical versus the orderly electrocardiographic limb lead display. Eighty-three students from two environments were randomized into two groups and were taught to determine frontal plane axis with one of the methods. The accuracy and time to determine the axis were tested on 10 electrocardiograms. In the United States the group using the classical display achieved 4.2 (+/-2.7) correct answers, whereas those using the orderly method achieved 6.8 (+/-3.0) (p = 0.0006). The classical group used 9.2 (+/-2.8) minutes to complete the test, whereas the orderly group needed 7.2 (+/-2.0) minutes (p = 0.015). The results achieved in Sweden were similar. The use of the orderly electrocardiographic limb lead display results in greater diagnostic accuracy in less time than the classical display when determining the frontal plane QRS axis.

Wound healing around and within saphenous vein bypass grafts

BACKGROUND

Myofibroblasts are a prominent cell type in wound healing. The goal of this study was to examine the extent to which myofibroblasts contribute to structural changes in saphenous vein bypass grafts.

METHODS AND RESULTS

Control veins and reversed saphenous vein bypass conduits of porcine carotid arteries were examined 2 to 4, 7 to 14, and 30 to 90 days after surgery with immunohistochemical markers of cellular proliferation (proliferating cell nuclear antigen), cytoskeletal protein production (alpha-smooth muscle actin and desmin), and histochemistry (Verhoeff's stain). Control veins demonstrated an extremely low level of cellular proliferation and no evidence of myofibroblasts in the adventitia, media, or intima. After bypass grafting, cellular proliferation was followed by myofibroblast formation, which occurred in the perivascular area and within the media. This was evidenced by a dense, but transient, expression of alpha-smooth muscle actin and a variable expression of desmin at 1 to 2 weeks, and with a significant increase in collagenous tissue by 1 to 3 months. Major cytoskeletal protein changes also occurred in the intima, with the appearance of alpha-smooth muscle actin positive cells at 7 to 14 days. alpha-Smooth muscle actin was still present in the neointima at 1 to 3 months, which is compatible with a persistent myofibroblast formation.

CONCLUSION

Myofibroblast formation occurs around and within saphenous veins after bypass grafting. This phenomenon is associated with significant remodeling of the vein grafts. The histologic changes are strikingly similar to events that occur during wound healing and may have implications for the development of neointimal hyperplasia and late vein graft disease.

Remodeling of autologous saphenous vein grafts. The role of perivascular myofibroblasts

BACKGROUND

Aortocoronary saphenous vein grafts (SVGs) undergo structural changes that render them susceptible to atherosclerosis. Accordingly, the origin of neointimal hyperplasia-was examined in porcine arterialized SVGs to determine the mechanism of vein graft remodeling.

METHODS AND RESULTS

At 2 to 4 days after surgery, the percentage of cells lacking differentiation markers characteristic for smooth muscle (SM) cells (ie, alpha-SM actin, desmin, and SM myosin) increased within the media of SVGs interposed in the carotid arteries (P < .001). At 7 to 14 days, these cells acquired a differentiated phenotype (ie, alpha-SM-actin positive/ variable desmin/SM-myosin negative) and accumulated in the neointima. At 3 months, the neointima was positive for alpha-SM actin but mostly negative for desmin, which contrasted with medial SMCs that were invariably positive for alpha-SM actin, desmin, and SM myosin. To determine the role of nonmuscle cells in the above process, perivascular wound fibroblasts were selectively labeled and found to translocate through the media of newly placed SVGs, contributing to neointimal formation. These migrating cells differentiated to myofibroblasts exhibiting sustained alpha-SM-actin expression. The intima of human SVGs, retrieved during repeat aortocoronary bypass surgery, exhibited the profile of cytoskeletal proteins that resembled myofibroblasts seen in porcine SVGs.

CONCLUSIONS

Perivascular fibroblasts may infiltrate injured media of arterialized SVGs, differentiate to myofibroblasts (acquiring alpha-SM actin), and contribute to vein graft remodeling. The similarities between porcine and human SVGs regarding the repertoire of cytoskeletal proteins suggest the involvement of myofibroblasts in graft remodeling in the clinical setting.

Race-ethnicity-specific variation in multiple-marker biochemical screening: alpha-fetoprotein, hCG, and estriol

OBJECTIVE

To identify any race-ethnicity-specific differences in serum alpha-fetoprotein (AFP), hCG, and unconjugated estriol (E3) levels in women between 14 and 21 weeks' gestation.

METHODS

Data from the 3-year period 1992-1994 were analyzed from 208,257 women who had AFP screening, of whom 155,142 also had hCG and 62,121 also had E3 screened, between 14 and 21 weeks' gestation. Subjects were categorized into four groups: white, black, Asian, and Hispanic.

RESULTS

There was a consistent pattern of analyte differences across gestational ages. Levels for AFP were generally higher in Asian and black women than in Hispanic and white women (median AFP at 16 weeks-31.2, 30.9, 27.4, 27.3, respectively), and levels of hCG and E3 were highest in Asians (hCG at 16 weeks-34.7, 30.3, 28.2, 26.8, respectively). Weight correction for AFP, hCG, and E3 levels did not compensate for the ethnic differences.

CONCLUSIONS

Because hCG and E3 demonstrate the same general pattern of differences as AFP among ethnic groups, averaging values for all ethnic groups tends inappropriately to lower calculated Down syndrome risks for black and Asian women. Additionally, the slopes of the curves are not parallel, such that separate data bases are preferable to multiplicative correction factors. Separate data bases should be used in laboratories with volume sufficient to permit the establishment of race-ethnicity-specific regressions. Use of separate data bases should result in more accurate screening.