Evaluation of "appropriate use criteria" for surgical decision-making in lumbar degenerative spondylolisthesis. A controlled, multicentre, prospective observational study.

INTRODUCTION: Selecting patients with lumbar degenerative spondylolisthesis (LDS) for surgery is difficult. Appropriate use criteria (AUC) have been developed to clarify the indications for LDS surgery but have not been evaluated in controlled studies. METHODS: This prospective, controlled, multicentre study involved 908 patients (561 surgical and 347 non-surgical controls; 69.5 ± 9.7y; 69% female), treated as per normal clinical practice. Their appropriateness for surgery was afterwards determined using the AUC. They completed the Core Outcome Measures Index (COMI) at baseline and 12 months' follow-up. Multiple regression adjusting for confounders evaluated the influence of appropriateness designation and treatment received on the 12-month COMI and achievement of MCIC (≥ 2.2-point-reduction). RESULTS: As per convention, appropriate (A) and uncertain (U) groups were combined for comparison with the inappropriate (I) group. For the adjusted 12-month COMI, the benefit of surgery relative to non-surgical care was not significantly greater for the A/U than the I group (p = 0.189). There was, however, a greater treatment effect of surgery for those with higher baseline COMI (p = 0.035). The groups' adjusted probabilities of achieving MCIC were: 83% (A/U, receiving surgery), 71% (I, receiving surgery), 50% (A/U, receiving non-surgical care), and 32% (I, receiving non-surgical care). CONCLUSIONS: A/U patients receiving surgery had the highest chances of achieving MCIC, but the AUC were not able to identify which patients had a greater treatment effect of surgery relative to non-surgical care. The identification of other characteristics that predict a greater treatment effect of surgery, in addition to baseline COMI, is required to improve decision-making.

Corticosteroid response predicts bronchopulmonary dysplasia status at 36 weeks in preterm infants treated with dexamethasone: A pilot study.

IMPORTANCE: A major barrier to therapeutic development in neonates is a lack of standardized drug response measures that can be used as clinical trial endpoints. The ability to quantify treatment response in a way that aligns with relevant downstream outcomes may be useful as a surrogate marker for new therapies, such as those for bronchopulmonary dysplasia (BPD). OBJECTIVE: To construct a measure of clinical response to dexamethasone that was well aligned with the incidence of severe BPD or death at 36 weeks' postmenstrual age. DESIGN: Retrospective cohort study. SETTING: Level IV Neonatal Intensive Care Unit. PARTICIPANTS: Infants treated with dexamethasone for developing BPD between 2010 and 2020. MAIN OUTCOME(S) AND MEASURE(S): Two models were built based on demographics, changes in ventilatory support, and partial pressure of carbon dioxide (pCO2 ) after dexamethasone administration. An ordinal logistic regression and regularized binary logistic model for the composite outcome were used to associate response level to BPD outcomes defined by both the 2017 BPD Collaborative and 2018 Neonatal Research Network definitions. RESULTS: Ninety-five infants were treated with dexamethasone before 36 weeks. Compared to the baseline support and demographic data at the time of treatment, changes in ventilatory support improved ordinal model sensitivity and specificity. For the binary classification, BPD incidence was well aligned with risk levels, increasing from 16% to 59%. CONCLUSIONS AND RELEVANCE: Incorporation of response variables as measured by changes in ventilatory parameters and pCO2 following dexamethasone administration were associated with downstream outcomes. Incorporating drug response phenotype into a BPD model may enable more rapid development of future therapeutics.

Effectiveness and safety of repeat dexamethasone for bronchopulmonary dysplasia.

OBJECTIVE: To describe effectiveness of repeat dexamethasone for bronchopulmonary dysplasia (BPD) and to evaluate adverse effects on growth. STUDY DESIGN: Retrospective study of infants treated with 1 or 2 courses of dexamethasone for BPD. Effectiveness was defined as successful step-down in respiratory support by end of treatment. Adverse effects on growth were analyzed and compared to untreated controls. RESULTS: A total of 132 dexamethasone-treated infants were identified. In total, 52% (69/132) of infants treated with initial dexamethasone achieved step-down in respiratory support compared to 38% (20/52) of infants with repeat dexamethasone. Growth trajectory did not significantly differ among infants treated with 1 or 2 courses of dexamethasone compared with controls (weight: P = 0.23, length: P = 0.68, and head circumference: P = 0.77). CONCLUSIONS: Repeat dexamethasone for BPD was less effective in weaning respiratory support compared to initial course. Changes in growth parameters to discharge were comparable between controls and infants treated with 1 or 2 dexamethasone courses.

A multidisciplinary chronic lung disease team in a neonatal intensive care unit is associated with increased survival to discharge of infants with tracheostomy.

OBJECTIVE: To determine if multidisciplinary team-based care of severe BPD/CLD infants improve survival to discharge. DESIGN/METHODS: Retrospective review of severe BPD/CLD infants cared for by dedicated multidisciplinary CLD team using consensus-driven protocols and guidelines. RESULTS: Total of 267 patients. Median gestational age was 26 weeks (IQR 24, 32); median birth-weight was 0.85 (IQR 0.64, 1.5). Twenty-four percent were preterm with severe BPD, 46% had other primary respiratory diseases (none BPD diseases). Total number of patients, proportion of patients with tracheostomy, prematurity, and genetic diagnoses increased over time. 88.8% survived to discharge. Unadjusted logistic regression showed that tracheostomy was not associated with odds of death; secondary pulmonary hypertension was associated with odds of tracheostomy (OR = 1.795 p value = 0.0264), or death (OR = 8.587 p value = <0.0001), or tracheostomy + death (OR = 13.58 p value = 0.0007). CONCLUSIONS: Over time, mortality improved for infants with tracheostomy cared for by a multidisciplinary severe BPD/CLD team. Secondary pulmonary hypertension was associated with tracheostomy, or death, or tracheostomy + death.

Multicenter Experience with Neurally Adjusted Ventilatory Assist in Infants with Severe Bronchopulmonary Dysplasia.

OBJECTIVE: The aim of this study is to determine patterns of neurally adjusted ventilatory assist (NAVA) use in ventilator-dependent preterm infants with evolving or established severe bronchopulmonary dysplasia (sBPD) among centers of the BPD Collaborative, including indications for its initiation, discontinuation, and outcomes. STUDY DESIGN: Retrospective review of infants with developing or established sBPD who were placed on NAVA after ≥4 weeks of mechanical ventilation and were ≥ 30 weeks of postmenstrual age (PMA). RESULTS: Among the 13 sites of the BPD collaborative, only four centers (31%) used NAVA in the management of infants with evolving or established BPD. A total of 112 patients met inclusion criteria from these four centers. PMA, weight at the start of NAVA and median number of days on NAVA, were different among the four centers. The impact of NAVA therapy was assessed as being successful in 67% of infants, as defined by the ability to achieve respiratory stability at a lower level of ventilator support, including extubation to noninvasive positive pressure ventilation or support with a home ventilator. In total 87% (range: 78-100%) of patients survived until discharge. CONCLUSION: We conclude that NAVA can be used safely and effectively in selective infants with sBPD. Indications and current strategies for the application of NAVA in infants with evolving or established BPD, however, are highly variable between centers. Although this pilot study suggests that NAVA may be successfully used for the management of infants with BPD, sufficient experience and well-designed clinical studies are needed to establish standards of care for defining the role of NAVA in the care of infants with sBPD.

Clinical classification criteria for neurogenic claudication caused by lumbar spinal stenosis. The N-CLASS criteria.

BACKGROUND CONTEXT: Because imaging findings of lumbar spinal stenosis (LSS) may not be associated with symptoms, clinical classification criteria based on patient symptoms and physical examination findings are needed. PURPOSE: The objective of this study was to develop clinical classification criteria that identify patients with neurogenic claudication (NC) caused by LSS. STUDY DESIGN: This study is a two-stage process that includes Phase 1, the Delphi process, and Phase 2, the cross-sectional study. PATIENT SAMPLE: Outpatients were recruited from spine clinics in five countries. OUTCOME MEASURE: The outcome measure includes items from the patients' history and physical examination. METHODS: In Phase 1, a list of potential predictors of NC caused by LSS was based on the available literature and was evaluated through a Delphi process involving 17 spine specialists (surgeons and non-surgeons) from eight countries. In Phase 2, 19 different clinical spine specialists from five countries identified patients they classified as having (1) NC caused by LSS, (2) radicular pain caused by lumbar disc herniation (LDH), or (3) non-specific low back pain (NSLBP) with radiating leg pain. The patients completed survey items and the specialists documented the examination signs. Coefficients from general estimating equation models were used to select predictors, to generate a clinical classification score, and to obtain a receiver operating characteristic curve. Conduction of the Delphi process, data management, and statistical analysis were partially supported by an unrestricted grant of less than 15,000 US dollars from Merck Sharp & Dohme. No fees were allocated to participating spine specialists. RESULTS: Phase 1 generated a final list of 46 items related to LSS. In Phase 2, 209 patients with leg pain caused by LSS (n=63), LDH (n=89), or NSLBP (n=57) were included. Criteria that independently predicted NC (p<.05) were age over 60 years, positive 30-second extension test, negative straight leg test, pain in both legs, leg pain relieved by sitting, and leg pain decreased by leaning forward or flexing the spine. A classification score using a weighted set of these criteria was developed. The proposed N-CLASS score ranged from 0 to 19 and had an area under the curve of 0.92, and the cutoff (>10/19) to obtain a specificity of >90.0% resulted in a sensitivity of 82.0%. CONCLUSIONS: Clinical criteria independently associated with neurogenic claudication due to LSS were identified. The use of these symptom and physical variables as a classification score for clinical research could improve homogeneity among enrolled patients.

[Place of interdisciplinary treatments in chronic low back pain]. / Place du traitement interdisciplinaire intensif dans la lombalgie chronique.

The treatment of chronic lumbar pain patients needs a global interdisciplinary approach when traditional conservative treatments do not fulfil their aims. One of the most efficient ways to proceed is using an interdisciplinary treatment program, including physiotherapeutic measures, occupational therapy and psychological support for 3 weeks. It is important that people in conflicts with insurances companies should be excluded from these treatments. It is also important that the reconditioning should continue over a long term to have a sustainable result.

La prise en charge de la lombalgie chronique nécessite une approche globale interdisciplinaire quand les approches traditionnelles n'apportent pas l'effet escompté. Une des manières les plus efficaces d'y arriver est par le biais de groupes de rééducation fonctionnelle durant 3 semaines. Ces approches englobent une prise en charge physique, ergothérapeutique et psychologique. Ces groupes permettent souvent de relancer des situations complexes, si d'autres conflits ­ comme par exemple, des conflits assécurologiques ­ sont absents. Il reste aussi important de poursuivre un reconditionnement sur le long terme pour avoir un résultat durable.

Clinical classification criteria for radicular pain caused by lumbar disc herniation: the radicular pain caused by disc herniation (RAPIDH) criteria.

BACKGROUND CONTEXT: Classification criteria are recommended for diseases that lack specific biomarkers to improve homogeneity in clinical research studies. Because imaging evidence of lumbar disc herniations (LDHs) may not be associated with symptoms, clinical classification criteria based on patient symptoms and physical examination findings are required. PURPOSE: This study aimed to produce clinical classification criteria to identify patients with radicular pain caused by LDH. STUDY DESIGN: The study design was a two-stage process. Phase 1 included a Delphi process and Phase 2 included a cohort study. PATIENT SAMPLE: The patient sample included outpatients recruited from spine clinics in five countries. OUTCOME MEASURES: The outcome measures were items from history and physical examination. MATERIALS AND METHODS: In Phase 1, 17 spine experts participated in a Delphi process to select symptoms and signs suggesting radicular pain caused by LDH. In Phase 2, 19 different clinical experts identified patients they confidently classified as presenting with (1) radicular pain caused by LDH, (2) neurogenic claudication (NC) caused by lumbar spinal stenosis, or (3) non-specific low back pain (NSLBP) with referred leg pain. Patients completed survey items and specialists documented examination signs. A score to predict radicular pain caused by LDH was developed based on the coefficients of the multivariate model. An unrestricted grant of less than US$15,000 was received from MSD: It was used to support the conception of the Delphi, data management, and statistical analysis. No fees were allocated to participating spine specialists. RESULTS: Phase 1 generated a final list of 74 potential symptoms and signs. In Phase 2, 209 patients with pain caused by LDH (89), NC (63), or NSLBP (57) were included. Items predicting radicular pain caused by LDH (p<.05) were monoradicular leg pain distribution, patient-reported unilateral leg pain, positive straight leg raise test <60° (or femoral stretch test), unilateral motor weakness, and asymmetric ankle reflex. The score had an AUC of 0.91. An easy-to-use weighted set of criteria with similar psychometric characteristics is proposed (specificity 90.4%, sensitivity 70.6%). CONCLUSIONS: Classification criteria for identifying patients with radicular pain caused by LDH are proposed. Their use could improve the homogeneity of patients enrolled in clinical research studies.

Development and validation of a questionnaire categorizing behavioral strategies in patients with chronic low back pain.

OBJECTIVE: The identification of helpful or unhelpful behavioral strategies for coping with pain would assist in optimizing the management of patients with chronic low back pain (CLBP). The objective was to develop and validate a questionnaire for categorizing behavioral strategies in patients with nonspecific CLBP. METHODS: (1) Development of a preliminary questionnaire based on a qualitative study in 25 patients with CLBP; (2) Item reduction and questionnaire validation by a multicenter international prospective study in patients with CLBP, with multiple correspondence analysis to identify behavioral profiles, whose characteristics and internal and external validities were assessed; 12-month study of treatments in 58 patients; (3) Evaluation of reproducibility in 30 patients. RESULTS: (1) The preliminary questionnaire had 87 items in eight pain-coping domains. (2) Three behavioral profiles were identified: effective coping, emotional distress, and kinesiophobia. The questionnaire was reduced to 21 items in seven domains. Cronbach's α indicated moderate internal consistency (0.47-0.66). External validity versus anxiety, depression, and coping strategies was good. As expected, functional restoration program was used more often by patients with kinesiophobia than by those with effective coping (50% vs. 25%, P<0.05). (3) Reproducibility was good (κ=0.70). CONCLUSION: This new, simple questionnaire allows the identification of three behavioral profiles, thus guiding the development of personalized management programs for NCLBP.

Rehospitalization in Infants Born < 29 Weeks' Gestation during the First 2 Years of Life: Risk Assessment.

OBJECTIVE: This study aims to determine risk factors for rehospitalization in extremely premature infants. STUDY DESIGN: A retrospective cohort study of 157 infants born < 29 weeks' gestational age assessing risk factors for rehospitalization through 2 years of life. RESULTS: Multivariable logistic regression showed that an increasing number of respiratory infections (odds ratio [OR]: 1.8 [1.1-3.1] per infection p = 0.03) and inhaled steroid use at 1 year (OR: 4.0 [1.3-12.1] p = 0.01) were predictive of hospital readmission. Diuretic (OR: 27 [1.01-1,000] p = 0.04) and oxygen (OR: 32 [3.1-333] p = 0.004) use at 1 year were predictive of pediatric intensive care unit admission. The number of respiratory infections (OR: 2.8 [1.7-4.5] p < 0.0001) with reflux/aspiration necessitating G-tube/Nissen fundoplication surgical intervention with or without G-tubes alone (OR: 21.3 [2.9-166.7] p = 0.02 and OR: 22.7 [CI, 2.4-200] p = 0.04) was predictive of increased number of rehospitalizations. CONCLUSIONS: Key modifiable risk factors identified were reflux/aspiration and ongoing respiratory infections. Critical time periods for diuretic, oxygen, and inhaled steroid use in this population occurred at the age of 1 year.

Impaired growth at birth and bronchopulmonary dysplasia classification: beyond small for gestational age.

OBJECTIVE: To correlate intrauterine and postnatal growth with bronchopulmonary dysplasia (BPD) classification at 36 weeks postmenstrual age (PMA). STUDY DESIGN: A retrospective cohort design reviewing medical records for infants < 29 weeks gestational age (GA) born between 2008 and 2010. BPD classification using physiological definition at 36 weeks PMA and growth parameters at birth and 36 weeks PMA were compared between GA subgroups. RESULTS: The cohort consisted of 140 infants. Median GA and birth weight (BW) were 27 weeks and 918 g, respectively. Twenty percent of infants had no BPD, 27% had mild BPD, 31% had moderate BPD, and 22% had severe BPD. While BW and GA remain major factors associated with severe BPD, we did not observe differences in weights at 36 weeks PMA. Length and head circumference were significantly impaired in infants born < 26 weeks GA at birth and 36 weeks PMA. Most importantly, all infants born < 26 weeks GA below the 25th percentile for weight developed moderate/severe BPD. CONCLUSION: Infants born < 26 weeks GA were smaller at birth and had significant postnatal growth impairment in linear and head circumference growth. Risk of developing BPD associated with lower BW for GA appeared to occur beyond the traditional small-for-gestational age (SGA) classification.

Validity of the French version of the Core Outcome Measures Index for low back pain patients: a prospective cohort study.

PURPOSE: Among the many questionnaires available to evaluate low back pain (LBP) patients, the Core Outcome Measures Index (COMI) has the unique advantage to investigate five dimensions using seven short questions. The aim of this study was to explore additional properties of the questionnaire in a French-speaking non-surgical population. METHODS: This study was conducted on 168 patients suffering from subacute or chronic LBP and followed up for 6 months in three French-speaking countries. In addition to basic psychometric properties (e.g., construct validity, floor and ceiling effect, reproducibility), internal validity was analyzed by a factor analysis using Cronbach's alpha. Responsiveness and sensitivity to change were assessed through minimal detectable change (MDC), effect size, and Minimal Clinically Important Improvement (MCII). We used an anchor-based method with receiver operating characteristic (ROC) curve analysis to assess MCII and the Patient Acceptable Symptom State. RESULTS: Construct validity, reliability (Cronbach's alpha = 0.87), reproducibility and the absence of floor and ceiling effects were confirmed. Factor analysis indicated a one-dimensional construct that validates the use of a sum score. The MDC (2.1) was inferior to the MCII (2.3). The limit below which the patient claims to be in a fair condition (Patient Acceptable Symptom State) was set at 3. CONCLUSIONS: The COMI is a self-report questionnaire with the capacity to easily and quickly explore several dimensions in patients with LBP that can be then summarized in a meaningful sum score. Additional knowledge provided by our study should encourage the widespread use of the COMI among the spine community.

Insurance coverage of pediatric burns: Switzerland versus USA.

Burn care and research have significantly improved over the past years. However, insurance coverage of such treatments does not reflect the improvements in this multi-disciplinary field. Government insurance policies in first world countries renown for burn care treatment, such as Switzerland and the United States, have not adapted to the complexity and longitudinal nature of burn care. Using case studies from both countries, we have analyzed both the institutional and policy approach to pediatric burn treatment coverage. Subsequently, by presenting the Shriners burn care model, we offer a policy recommendation to both the Swiss and the American governments to better their present legislation and infrastructure on pediatric burn coverage.

Cost-utility analysis of a three-month exercise programme vs usual care following multidisciplinary rehabilitation for chronic low back pain.

OBJECTIVE: To assess the cost-utility of an exercise programme vs usual care after functional multidisciplinary rehabilitation in patients with chronic low back pain. DESIGN: Cost-utility analysis alongside a randomized controlled trial. SUBJECTS/PATIENTS: A total of 105 patients with chronic low back pain. METHODS: Chronic low back pain patients completing a 3-week functional multidisciplinary rehabilitation were randomized to either a 3-month exercise programme (n = 56) or usual care (n = 49). The exercise programme consisted of 24 training sessions during 12 weeks. At the end of functional multidisciplinary rehabilitation and at 1-year follow-up quality of life was measured with the SF-36 questionnaire, converted into utilities and transformed into quality--adjusted life years. Direct and indirect monthly costs were measured using cost diaries. The incremental cost-effectiveness ratio was calculated as the incremental cost of the exercise programme divided by the difference in quality-adjusted life years between both groups. RESULTS: Quality of life improved significantly at 1-year follow-up in both groups. Similarly, both groups significantly reduced total monthly costs over time. No significant difference was observed between groups. The incremental cost-effectiveness ratio was 79,270 euros. CONCLUSION: Adding an exercise programme after functional multidisciplinary rehabilitation compared with usual care does not offer significant long-term benefits in quality of life and direct and indirect costs.

Role of physical exercise in low back pain rehabilitation: a randomized controlled trial of a three-month exercise program in patients who have completed multidisciplinary rehabilitation.

STUDY DESIGN: Randomized controlled trial with 1-year follow-up. OBJECTIVE: To analyze the effects of an exercise program or routine follow-up on patients with chronic low back pain who have completed functional multidisciplinary rehabilitation. The short- and long-term outcome in terms of symptoms and physical and social functioning was compared. SUMMARY OF BACKGROUND DATA: Systematic reviews have shown that functional multidisciplinary rehabilitation improves physical function and reduces pain in patients with chronic low back pain. However, long-term maintenance of these improvements is inconsistent and the role of exercise in achieving this goal is unclear. METHODS: One hundred five chronic patients with low back pain who had completed a 3-week functional multidisciplinary rehabilitation program were randomized to either a 3-month exercise program (n = 56) or routine follow-up (n = 49). The exercise program consisted of 24 training sessions during 12 weeks. Patients underwent evaluations of trunk muscle endurance, cardiovascular endurance, lumbar spine mobility (flexion and extension range-of-motion, fingertip-to-floor distance), pain and perceived functional ability at the beginning and the end of functional multidisciplinary rehabilitation, at the end of the exercise program (3 months) and at 1-year follow-up. Disability was also assessed at the same time points except at the beginning of functional multidisciplinary rehabilitation. RESULTS: At the end of the functional multidisciplinary rehabilitation, both groups improved significantly in all physical parameters except flexion and extension range-of-motion. At the 3 month and 1 year follow-up, both groups maintained improvements in all parameters except for cardiovascular endurance. Only the exercise program group improved in disability score and trunk muscle endurance. No differences between groups were found. CONCLUSION: A favorable long-term outcome was observed after functional multidisciplinary rehabilitation in both patient groups. Patients who participated in an exercise program obtained some additional benefits. The relevance of these benefits to overall health status need to be further investigated.

Inflammatory markers and mediators in tracheal fluid of premature infants treated with inhaled nitric oxide.

OBJECTIVE: We compared serial measurements of inflammatory mediators and markers in infants treated with inhaled nitric oxide or placebo to assess the effects of inhaled nitric oxide therapy on lung inflammation during bronchopulmonary dysplasia. We investigated relationships between respiratory severity scores and airway concentrations of inflammatory markers/mediators. METHODS: As part of the Nitric Oxide (to Prevent) Chronic Lung Disease trial, a subset of 99 infants (52 placebo-treated infants and 47 inhaled nitric oxide-treated infants; well matched at baseline) had tracheal aspirate fluid collected at baseline, at 2 to 4 days, and then weekly while still intubated during study gas treatment (minimum of 24 days). Fluid was assessed for interleukin-1beta, interleukin-8, transforming growth factor-beta, N-acetylglucosaminidase, 8-epi-prostaglandin F2alpha, and hyaluronan. Results were normalized to total protein and secretory component of immunoglobulin A. RESULTS: At baseline, there was substantial variability of each measured substance and no correlation between tracheal aspirate fluid levels of any substance and respiratory severity scores. Inhaled nitric oxide administration did not result in any time-matched significant change for any of the analytes, compared with the placebo-treated group. There was no correlation between any of the measured markers/mediators and respiratory severity scores throughout the 24 days of study gas administration. In the posthoc analysis of data for inhaled nitric oxide-treated infants, there was a difference at baseline in 8-epi-prostaglandin F2alpha levels for infants who did (n = 21) and did not (n = 26) develop bronchopulmonary dysplasia at postmenstrual age of 36 weeks. CONCLUSIONS: Inhaled nitric oxide, as administered in this study, seemed to be safe. Its use was not associated with any increase in airway inflammatory substances.

[Surgical treatment of radicular pain using minimally invasive techniques]. / Traitement chirurgical des douteurs radiculaires par techniques minimales invasives.

Radicular pain can be caused by disc herniation, lateral stenosis, isthmic spondylolisthesis with foraminal stenosis, or foraminal encroachment due to asymmetrical disc degeneration or scoliosis. Surgery is indicated following failure of conservative treatment. Minimally invasive discectomy is indicated for subjects presenting with radicular pain with or without neurological deficit and appropriate sized herniation in MRI. It offers equivalent efficacy but quicker recovery than microdiscectomy. Minimally invasive fusion is indicated for radicular pain due to foraminal compression in isthmic spondylolisthesis, asymmetric disc degeneration or scoliosis. It allows decrease in blood loss and postoperative pain. A less invasive technique should nevertheless not replace properly conducted conservative treatment.

Low levels of tissue inhibitors of metalloproteinases with a high matrix metalloproteinase-9/tissue inhibitor of metalloproteinase-1 ratio are present in tracheal aspirate fluids of infants who develop chronic lung disease.

OBJECTIVE: The pathogenesis of chronic lung disease (CLD) involves inflammation with proteolytic damage to lung extracellular matrix. Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases that, acting in concert with their tissue inhibitors, tightly orchestrate extracellular matrix morphogenesis and repair after injury. Imbalances in their levels relative to that of their inhibitors have been implicated in diseases characterized by matrix disruption and remodeling. We investigated the possibility that imbalances in MMP-9 and MMP-2 relative to their tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2, respectively, in tracheal aspirates of preterm infants may be involved in the development of CLD. METHODS: Serial tracheal aspirates collected from birth until extubation in 49 ventilated preterm infants (24-32 weeks' gestations) were analyzed for MMP-2, MMP-9, TIMP-1, and TIMP-2. Data normalized by TA values of free secretory component of immunoglobulin A were compared for CLD (n = 22) versus no CLD (n = 27). Also, known clinical predictors of CLD (gestational age, birth weight, and sex) were assessed for both groups. Association of predictors with the outcome CLD was assessed by logistic regression. RESULTS: Mean gestational age was lower in CLD infants, but birth weight and gender were comparable for both groups. CLD infants had significantly lower TIMP-1 level with higher MMP-9/TIMP-1 ratio during the first 2 weeks of life and low TIMP-2 and MMP-2 levels during the first 3 days of life compared with no-CLD infants. Logistic regression analysis indicated that the findings are predictive of CLD. CONCLUSIONS: We conclude that low tracheal aspirate levels of TIMPs, with a high MMP-9/TIMP-1 ratio early in life, are associated with subsequent development of CLD.

Lung microvascular adaptation in infants with chronic lung disease.

Microvascular development is critical for normal lung maturation. The aims of this study were (1) to quantitatively and qualitatively assess lung microvascular growth in the human fetus, from 22 to 40 weeks' gestation, and (2) to compare development in these infants to those with mild, moderate and severe chronic lung disease (CLD). Using 1- and 4-microm thick sections and electron microscopy, lungs were morphometrically assessed for surface density of distal air spaces; volume density of parenchymal vessels having an air-blood barrier (ABB); percent of distal air space wall having an ABB, and capillary loading, defined as ABB/mm2 of epithelial surface area. The percent of vessels with ABB increased in controls during development in parallel with increasing lung parenchyma. Infants with severe CLD had fewer ABBs and less capillary loading than controls up to 34 weeks' post-conceptional age (PCA), but by 36-40 weeks, showed catch-up growth. Microvasculature vessel diameter, septal thickness, and air sac diameter at 36-40 weeks' PCA were increased with severe CLD, and vessels were more distant from the air surface. We conclude that infants with severe CLD have both stunted secondary septation and microvascular development, but over time, the primary septal wall adapts by thinning and increasing the number of ABBs, thereby taking on the function of secondary septa.