Physiology-based minimum clinically important difference thresholds in adult laryngotracheal stenosis.

OBJECTIVES/HYPOTHESIS: Delivering evidence-based patient care is predicated on the availability of objective and validated outcome measures. We aimed to calculate physiology-based minimum clinically important difference (MCID) values for adult laryngotracheal stenosis (LTS). STUDY DESIGN: Prospective observational study. METHODS: Patient demographics, morbidities, and stenosis severity were assessed preoperatively. Flow-volume loops and Medical Research Council (MRC) dyspnea grades were measured in 21 males and 44 females before and 6 to 8 weeks after airway surgery, and before treating recurrent disease in 10 patients. Anchor and distribution-based methodologies were used to calculate MCIDs for treatment efficacy and disease recurrence respectively. RESULTS: The mean age at treatment was 46 ± 16 years. The most common etiology was idiopathic subglottic stenosis (38%). Most lesions (66%) obstructed >70% of the lumen. There were strong correlations between treatment-related changes in total peak flow (TPF) (ΔTPF) (peak expiratory flow + |peak inspiratory flow|) and the ratio of area under the flow-volume loop (AUC) to forced vital capacity (FVC) (ΔAUCTotal /FVC), and treatment-related changes in the MRC grade (ΔMRC) (r = -0.76 and r = -0.82, respectively). Both TPF and AUCTotal /FVC discriminated between effective (ΔMRC <0) and ineffective (ΔMRC ≥0) interventions, yielding MCID values of 4.2 L/s for TPF and 2.1 L(2) /s for AUCTotal /FVC, respectively. Ten patients required airway treatment for recurrent disease, and TPF and AUCTotal /FVC levels had distribution-based MCID values of 0.9 and 0.6, respectively. CONCLUSIONS: Flow-volume loops provide a quantitative method of objectively assessing outcomes in LTS. TPF is the most convenient index for this purpose, but AUCTotal /FVC provides marginally greater sensitivity and specificity.

Management and prognosis of primary tracheal cancer: a national analysis.

OBJECTIVES/HYPOTHESIS: To perform a national review of the incidence and treatment of primary tracheal cancer and to identify gaps in service provision and factors associated with survival. STUDY DESIGN: Retrospective analysis of Hospital Episode Statistics data for England between 1996 and 2011. METHODS: Information about age, sex, morbidity, provider trust, diagnostic delay, nature of hospital admission and treatment, and palliation-free survival were recorded. The relationship between variables and survival was explored with Cox regression. RESULTS: There were 874 patients, giving an incidence of 0.9 per million. Mean age at diagnosis was 66 ± 13, and there were 456 (52%) males. Mean presentation to diagnosis latency was 2.5 ± 8 months, and 40% of patients presented as emergency admissions. There were 19 cases of oesophageal involvement and 241 cases of bronchopulmonary involvement; and 188 patients developed distant metastases. There were 60 curative resections (6.9%), which was the most significant predictor of palliation-free survival (hazard ratio: 0.23; 95% confidence interval 0.13-0.38). Other prognostic variables included age, sex, emergency admission, interventional bronchoscopy, chemotherapy, oesophageal involvement, and distant metastases. Ten-year palliation-free survival was 60.8% with curative resection and 19.5% overall. Eighty-six percent of patients were treated in units that treated fewer than one patient per year. CONCLUSION: Tracheal cancer is under-recognized and under-treated. Early diagnosis, access to interventional bronchoscopy, and surgical treatment in specialist units may improve the survival of patients with this condition.

Use of pressure-volume loops for physiological assessment of adult laryngotracheal stenosis.

OBJECTIVES/HYPOTHESIS: To assess the utility of intraoperative pressure-volume curves as an objective method of physiological disease stratification and outcomes assessment in adult laryngotracheal stenosis. STUDY DESIGN: Prospective observational study. METHODS: We prospectively studied 42 tracheotomy-free patients undergoing endoscopic laryngotracheoplasty over 18 months. Patient and lesion characteristics were obtained. Dyspnea severity was assessed using the Medical Research Council scale. Preoperative spirometry and intraoperative pulmonary compliance were recorded. RESULTS: There were 19 male and 23 female patients, and the mean age at treatment was 44 ± 16 years. There were 14 Myer-Cotton 1 lesions and 14 and 13 patients had grade 2 or 3 stenoses, respectively. Pulmonary compliance was strongly correlated with anatomical stenosis severity (r = 0.8, P < .0001) and perceptual dyspnea severity (r = 0.73, P < .0001). The strengths of correlation between pulmonary compliance and anatomical stenosis severity was significantly greater than those between forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow. The strength of correlation between pulmonary compliance and perceptual dyspnea severity was significantly greater than those between FEV1 and FVC with perceptual dyspnea severity. The two independent determinants of pulmonary compliance were Myer-Cotton stenosis severity (P < .0001) and patient age (P = .013). CONCLUSIONS: Pulmonary compliance provides an objective measure of physiological airway impairment. It correlates well with anatomical disease severity and perceptual dyspnea severity. Its more widespread use in adult patients and research into its utility in pediatric airway stenosis is recommended.

Diagnosis of laryngotracheal stenosis from routine pulmonary physiology using the expiratory disproportion index.

OBJECTIVE/HYPOTHESIS: The study's objective was to determine the utility of expiratory disproportion index (EDI), the ratio of forced expiratory volume in 1 second (FEV1) to peak expiratory flow rate (PEFR) (EDI = FEV1[L] /PEFR[L/s] × 100), in differentiating between laryngotracheal stenosis (LTS) and other respiratory diagnoses. LTS is an uncommon complication of mechanical ventilation or vasculitis or a manifestation of airway compression or malignancy. It frequently masquerades as asthma and evades timely diagnosis, causing prolonged morbidity and airway-related mortality. STUDY DESIGN: Observational study. METHODS: We compared spirometry results of 9,357 healthy subjects and nonstenosis pulmonary patients with 217 cases of LTS. Bootstrap analysis, receiver-operating characteristic (ROC) statistics, and Pearson correlation were used to assess the diagnostic utility of the EDI and its correlation with stenosis severity. RESULTS: Mean EDI values were 36 ± 7 in nonstenosis cases, 76 ± 17 in benign stenoses, and 69 ± 23 in tracheal cancer (P < .0001). A significant correlation existed between anatomic stenosis severity and EDI (P < .0001; R = 0.61). Area under the ROC curve was 0.98, and at a threshold of >50, EDI had a sensitivity of 95.9% and a specificity of 94.2% in differentiating between stenosis and nonstenosis cases. CONCLUSIONS: EDI can reliably diagnose LTS using routine lung function data. Its simplicity and clinical utility, first recognized by Duncan Empey, are underpinned by a unique physiology whereby PEFR, being determined by total tracheobronchial tree resistance, falls disproportionately compared with FEV1 , which is determined within small intrathoracic airways. EDI provides valuable information about the presence and extent of LTS particularly in nonspecialist clinical settings and its routine inclusion within standard lung function reports could prevent the prolonged morbidity and mortality that currently result from missed and delayed diagnoses.

Remote ischemic preconditioning in percutaneous coronary revascularization: a double-blind randomized controlled clinical trial.

OBJECTIVE: To assess the impact of pre-procedural remote ischemic preconditioning on the incidence of myocardial complications following percutaneous coronary intervention. BACKGROUND: Ischemic preconditioning of a remote vascular territory improves the subsequent ischemic tolerance of distant organs. METHOD: The Myocardial Event Reduction with Ischemic Preconditioning Therapy (MERIT) trial recruited 80 consecutive patients undergoing elective angioplasty with drug-eluting stents to receive two 5-min lower limb tourniquet occlusions or an un-inflated tourniquet (controls) 1 h before the procedure. The primary outcome was troponin T level at 24 h. Secondary outcomes were intra-procedural chest pain and ST-segment deviation. RESULTS: 6 patients in the control group and 2 in the ischemic preconditioning group had pre-procedural raised troponin T (p = 0.23). This increased to 16 (40%) in the control group and 5 (12.5%) in the study group at 24 h (p = 0.01). Fewer patients in the study group experienced intra-procedural chest pain (1 vs. 7, p = 0.056). Mean ST-segment deviation time was 13 ± 35 s in the study group and 58 ± 118 s in the control group (p = 0.02). At a mean follow-up of 11 months, the major adverse cardiac event rate did not differ significantly between the groups. CONCLUSION: These data suggest that ischemic preconditioning reduces the absolute risk of post-procedure cardiomyocyte necrosis by 27.5%, and reduces intra-procedural chest pain and ST-segment deviation in patients undergoing percutaneous coronary interventions. We suggest its routine use in percutaneous coronary intervention, although the long-term prognostic impact in this patient group warrants further investigation.

Quantifying the physiology of laryngotracheal stenosis: changes in pulmonary dynamics in response to graded extrathoracic resistive loading.

OBJECTIVES/HYPOTHESIS: A model of airway obstruction was developed to study the impact of changes in airway resistance on ventilatory mechanics. This was used to derive quantitative indices of airway obstruction to aid in the objective diagnosis and physiological monitoring of adult patients with laryngotracheal stenosis (LTS). METHODS: Six airway resistors, the characteristics of which mirrored the selective impediment to inspiratory airflow that occurs in patients with LTS, were created and calibrated. Maximum-effort flow-volume loops were obtained from 15 volunteers with resistors placed in series with the spirometer. Diagnostic and monitoring performances of various flow-volume indices were assessed with receiver-operating characteristics (ROC) and analysis of variance (ANOVA), respectively. Promising indices were further evaluated in patients with LTS. RESULTS: Experimentally, the ratio of expiratory and inspiratory flows at midvital capacity (MEF50/MIF50) and peak expiratory to inspiratory flow ratio (PEF/PIF) had diagnostic sensitivities of 87% and 89%, respectively. The best index, both experimentally and clinically, was the ratio of area under the expiratory and inspiratory curves (ratio of integrals), with experimental and clinical sensitivities of 97% and 100%, respectively. A clinical specificity of 95%, and area under the curve of 0.965 were achieved for this index. Both PEF/PIF and the ratio of integrals could identify step changes in airway resistance greater than 10 cmH2O . sec . L (P < .05; ANOVA). CONCLUSIONS: Flow-volume testing is simple and noninvasive and can be used to quantify the diagnosis and physiological monitoring of patients with LTS. The ratio of areas under the expiratory and inspiratory curves appears to be the optimal index for this purpose.

Aarskog syndrome with aortic root dilatation and sub-valvular aortic stenosis: surgical management.

Aarskog syndrome is a familial condition associated with craniofacial anomalies, genital malformations and short stature. Affected children have significantly higher chance of having congenital heart disease (CHD) than the general population. We report the case of a child afflicted with progressive aortic root dilatation and sub-valvular aortic stenosis, successfully managed with aortic root and valve replacement. Given the association between Aarskog syndrome and CHD, cardiac surveillance should be undertaken in all affected children.