Clinical impact of EGFR and KRAS mutations in surgically treated unifocal and multifocal lung adenocarcinoma.

Background: Epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma (KRAS) are the two most common oncogenic drivers in lung adenocarcinoma, and their roles still need further exploration. Here we aimed to compare the clinical impact of EGFR and KRAS mutations on disease progression in resected unifocal and multifocal lung adenocarcinoma. Methods: Clinicopathologic and genomic data were collected for patients who underwent resection of lung adenocarcinoma from 2008 to 2022 at Stanford University Hospital. Retrospective review was performed in 241 patients whose tumors harbored EGFR (n=150, 62.2%) or KRAS (n=91, 37.8%) mutations. Clinical outcome was analyzed with special attention to the natural history of secondary nodules in multifocal cases wherein the dominant tumor had been resected. Results: We confirm that compared with EGFR mutations, patients with KRAS mutations had more smokers, larger tumor size, higher TNM stage, higher positron emission tomography (PET)/computed tomography (CT) standard uptake value max, higher tumor mutation burden, and worse disease-free survival and overall survival on univariate analysis. For patients with multifocal pulmonary nodules, the median follow-up of unresected secondary nodules was 55 months. Secondary nodule progression-free survival (SNPFS) was significantly worse for patients with KRAS mutations than those with EGFR mutations (mean 40.3±6.6 vs. 67.7±6.5 months, P=0.004). Univariate analysis showed tumor size, tumor morphology, pathologic TNM stage, and KRAS mutations were significantly associated with SNPFS, while multivariate analysis showed only KRAS mutations were independently associated with worse SNPFS (hazard ratio 1.752, 95% confidence interval: 1.017-3.018, P=0.043). Conclusions: Resected lung adenocarcinomas with KRAS mutations have more aggressive clinicopathological features and confer worse prognosis than those with EGFR mutations. Secondary pulmonary nodules in multifocal cases with dominant KRAS-mutant tumors have more rapid progression of the secondary nodules.

Interstitial macrophages are a focus of viral takeover and inflammation in COVID-19 initiation in human lung.

Early stages of deadly respiratory diseases including COVID-19 are challenging to elucidate in humans. Here, we define cellular tropism and transcriptomic effects of SARS-CoV-2 virus by productively infecting healthy human lung tissue and using scRNA-seq to reconstruct the transcriptional program in "infection pseudotime" for individual lung cell types. SARS-CoV-2 predominantly infected activated interstitial macrophages (IMs), which can accumulate thousands of viral RNA molecules, taking over 60% of the cell transcriptome and forming dense viral RNA bodies while inducing host profibrotic (TGFB1, SPP1) and inflammatory (early interferon response, CCL2/7/8/13, CXCL10, and IL6/10) programs and destroying host cell architecture. Infected alveolar macrophages (AMs) showed none of these extreme responses. Spike-dependent viral entry into AMs used ACE2 and Sialoadhesin/CD169, whereas IM entry used DC-SIGN/CD209. These results identify activated IMs as a prominent site of viral takeover, the focus of inflammation and fibrosis, and suggest targeting CD209 to prevent early pathology in COVID-19 pneumonia. This approach can be generalized to any human lung infection and to evaluate therapeutics.

Phenotyping EMT and MET cellular states in lung cancer patient liquid biopsies at a personalized level using mass cytometry.

Malignant pleural effusions (MPEs) can be utilized as liquid biopsy for phenotyping malignant cells and for precision immunotherapy, yet MPEs are inadequately studied at the single-cell proteomic level. Here we leverage mass cytometry to interrogate immune and epithelial cellular profiles of primary tumors and pleural effusions (PEs) from early and late-stage non-small cell lung cancer (NSCLC) patients, with the goal of assessing epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) states in patient specimens. By using the EMT-MET reference map PHENOSTAMP, we observe a variety of EMT states in cytokeratin positive (CK+) cells, and report for the first time MET-enriched CK+ cells in MPEs. We show that these states may be relevant to disease stage and therapy response. Furthermore, we found that the fraction of CD33+ myeloid cells in PEs was positively correlated to the fraction of CK+ cells. Longitudinal analysis of MPEs drawn 2 months apart from a patient undergoing therapy, revealed that CK+ cells acquired heterogeneous EMT features during treatment. We present this work as a feasibility study that justifies deeper characterization of EMT and MET states in malignant cells found in PEs as a promising clinical platform to better evaluate disease progression and treatment response at a personalized level.

The colocatome as a spatial -omic reveals shared microenvironment features between tumour-stroma assembloids and human lung cancer.

Computational frameworks to quantify and compare microenvironment spatial features of in-vitro patient-derived models and clinical specimens are needed. Here, we acquired and analysed multiplexed immunofluorescence images of human lung adenocarcinoma (LUAD) alongside tumour-stroma assembloids constructed with organoids and fibroblasts harvested from the leading edge (Tumour-Adjacent Fibroblasts;TAFs) or core (Tumour Core Fibroblasts;TCFs) of human LUAD. We introduce the concept of the "colocatome" as a spatial -omic dimension to catalogue all proximate and distant colocalisations between malignant and fibroblast subpopulations in both the assembloids and clinical specimens. The colocatome expands upon the colocalisation quotient (CLQ) through a nomalisation strategy that involves permutation analysis and thereby allows comparisons of CLQs under different conditions. Using colocatome analysis, we report that both TAFs and TCFs protected cancer cells from targeted oncogene treatment by uniquely reorganising the tumour-stroma cytoarchitecture, rather than by promoting cellular heterogeneity or selection. Moreover, we show that the assembloids' colocatome recapitulates the tumour-stroma cytoarchitecture defining the tumour microenvironment of LUAD clinical samples and thereby can serve as a functional spatial readout to guide translational discoveries.

KRAS(G12D) drives lepidic adenocarcinoma through stem-cell reprogramming.

Many cancers originate from stem or progenitor cells hijacked by somatic mutations that drive replication, exemplified by adenomatous transformation of pulmonary alveolar epithelial type II (AT2) cells1. Here we demonstrate a different scenario: expression of KRAS(G12D) in differentiated AT1 cells reprograms them slowly and asynchronously back into AT2 stem cells that go on to generate indolent tumours. Like human lepidic adenocarcinoma, the tumour cells slowly spread along alveolar walls in a non-destructive manner and have low ERK activity. We find that AT1 and AT2 cells act as distinct cells of origin and manifest divergent responses to concomitant WNT activation and KRAS(G12D) induction, which accelerates AT2-derived but inhibits AT1-derived adenoma proliferation. Augmentation of ERK activity in KRAS(G12D)-induced AT1 cells increases transformation efficiency, proliferation and progression from lepidic to mixed tumour histology. Overall, we have identified a new cell of origin for lung adenocarcinoma, the AT1 cell, which recapitulates features of human lepidic cancer. In so doing, we also uncover a capacity for oncogenic KRAS to reprogram a differentiated and quiescent cell back into its parent stem cell en route to adenomatous transformation. Our work further reveals that irrespective of a given cancer's current molecular profile and driver oncogene, the cell of origin exerts a pervasive and perduring influence on its subsequent behaviour.

p53 governs an AT1 differentiation programme in lung cancer suppression.

Lung cancer is the leading cause of cancer deaths worldwide1. Mutations in the tumour suppressor gene TP53 occur in 50% of lung adenocarcinomas (LUADs) and are linked to poor prognosis1-4, but how p53 suppresses LUAD development remains enigmatic. We show here that p53 suppresses LUAD by governing cell state, specifically by promoting alveolar type 1 (AT1) differentiation. Using mice that express oncogenic Kras and null, wild-type or hypermorphic Trp53 alleles in alveolar type 2 (AT2) cells, we observed graded effects of p53 on LUAD initiation and progression. RNA sequencing and ATAC sequencing of LUAD cells uncovered a p53-induced AT1 differentiation programme during tumour suppression in vivo through direct DNA binding, chromatin remodelling and induction of genes characteristic of AT1 cells. Single-cell transcriptomics analyses revealed that during LUAD evolution, p53 promotes AT1 differentiation through action in a transitional cell state analogous to a transient intermediary seen during AT2-to-AT1 cell differentiation in alveolar injury repair. Notably, p53 inactivation results in the inappropriate persistence of these transitional cancer cells accompanied by upregulated growth signalling and divergence from lung lineage identity, characteristics associated with LUAD progression. Analysis of Trp53 wild-type and Trp53-null mice showed that p53 also directs alveolar regeneration after injury by regulating AT2 cell self-renewal and promoting transitional cell differentiation into AT1 cells. Collectively, these findings illuminate mechanisms of p53-mediated LUAD suppression, in which p53 governs alveolar differentiation, and suggest that tumour suppression reflects a fundamental role of p53 in orchestrating tissue repair after injury.

Tracheal stenosis and airway complications in the Coronavirus Disease-19 era.

BACKGROUND: Severe Coronavirus Disease 2019 (COVID-19) infection is associated with prolonged intubation and its complications. Tracheal stenosis is one such complication that may require specialized surgical management. We aimed to describe the surgical management of post-COVID-19 tracheal stenosis. METHODS: This case series describes consecutive patients with tracheal stenosis from intubation for severe COVID-19 infection at our single, tertiary academic medical center between January 1st, 2021, and December 31st, 2021. Patients were included if they underwent surgical management with tracheal resection and reconstruction, or bronchoscopic intervention. Operative through six-month, symptom-free survival and histopathological analysis of resected trachea were reviewed. RESULTS: Eight patients are included in this case series. All patients are female, and most (87.5%) are obese. Five patients (62.5%) underwent tracheal resection and reconstruction (TRR), while three patients (38.5%) underwent non-resection-based management. Among patients who underwent TRR, six-month symptom free survival is 80%; one patient (20%) required tracheostomy after TRR due to recurrent symptoms. Two of the three (66.7%) of patients who underwent non-resection-based management experienced durable relief from symptoms of tracheal stenosis with tracheal balloon dilation, and the remaining patient required laser excision of tracheal tissue prior to experiencing symptomatic relief. CONCLUSIONS: The incidence of tracheal stenosis may increase as patients recover from severe COVID-19 infection requiring intubation. Management of tracheal stenosis with TRR is safe and effective, with comparable rates of success to TRR for non-COVID-19 tracheal stenosis. Non-resection-based management is an option to manage tracheal stenosis in patients with less severe stenosis or in poor surgical candidates.

Organoid modeling of lung-resident immune responses to SARS-CoV-2 infection.

Tissue-resident immunity underlies essential host defenses against pathogens, but analysis in humans has lacked in vitro model systems where epithelial infection and accompanying resident immune cell responses can be observed en bloc. Indeed, human primary epithelial organoid cultures typically omit immune cells, and human tissue resident-memory lymphocytes are conventionally assayed without an epithelial infection component, for instance from peripheral blood, or after extraction from organs. Further, the study of resident immunity in animals can be complicated by interchange between tissue and peripheral immune compartments. To study human tissue-resident infectious immune responses in isolation from secondary lymphoid organs, we generated adult human lung three-dimensional air-liquid interface (ALI) lung organoids from intact tissue fragments that co-preserve epithelial and stromal architecture alongside endogenous lung-resident immune subsets. These included T, B, NK and myeloid cells, with CD69+CD103+ tissue-resident and CCR7- and/or CD45RA- TRM and conservation of T cell receptor repertoires, all corresponding to matched fresh tissue. SARS-CoV-2 vigorously infected organoid lung epithelium, alongside secondary induction of innate cytokine production that was inhibited by antiviral agents. Notably, SARS-CoV-2-infected organoids manifested adaptive virus-specific T cell activation that was specific for seropositive and/or previously infected donor individuals. This holistic non-reconstitutive organoid system demonstrates the sufficiency of lung to autonomously mount adaptive T cell memory responses without a peripheral lymphoid component, and represents an enabling method for the study of human tissue-resident immunity.

Half of Anastomotic Leaks After Esophagectomy Are Undetected on Initial Postoperative Esophagram.

BACKGROUND: The sensitivity of fluoroscopic esophagography with oral administration of contrast material to exclude anastomotic leak after esophagectomy is not well documented, and the consequences of missing a leak in this setting have not been previously described. METHODS: We performed a retrospective cohort study of a prospectively maintained institutional database of patients undergoing esophagectomy with esophagogastric anastomosis from 2008 to 2020. Relevant details of leaks, management, and outcomes were obtained from the database and formal chart review. Statistical analysis was performed to compare patients with and without leaks and those with false-negative vs positive esophagrams. RESULTS: There were 384 patients who underwent esophagectomy with gastric reconstruction; the majority were Ivor-Lewis (82%), and 51% were wholly or partially minimally invasive. By use of a broad definition of leak, 55 patients (16.7%) developed an anastomotic leak. Of the 55 patients, 27 (49%) who ultimately were found to have a leak initially had a normal esophagram result (performed on average on postoperative day 6). Those with a normal initial esophagram result were more likely to have an uncontained leak (81% vs 29%; P < .01), to require unplanned readmission (70% vs 39%; P = .02), and to undergo reoperation (44% vs 11%; P < .01). CONCLUSIONS: Early postoperative esophagrams intended to evaluate anastomotic integrity have a low sensitivity of 51%, and leaks missed on the initial esophagram have greater clinical consequences than those identified on the initial esophagram. These findings suggest that a high index of suspicion must be maintained even after a normal esophagram result and call into question the common practice of using this test to triage patients for diet advancement.

Positron emission tomography/computed tomography differentiates resectable thymoma from anterior mediastinal lymphoma.

OBJECTIVE: Discrete anterior mediastinal masses most often represent thymoma or lymphoma. Lymphoma treatment is nonsurgical and requires biopsy. Noninvasive thymoma is ideally resected without biopsy, which may potentiate pleural metastases. This study sought to determine if clinical criteria or positron emission tomography/computed tomography could accurately differentiate the 2, guiding a direct surgery versus biopsy decision. METHODS: A total of 48 subjects with resectable thymoma and 29 subjects with anterior mediastinal lymphoma treated from 2006 to 2019 were retrospectively examined. All had pretreatment positron emission tomography/computed tomography and appeared resectable (solitary, without clear invasion or metastasis). Reliability of clinical criteria (age and B symptoms) and positron emission tomography/computed tomography maximum standardized uptake value were assessed in differentiating thymoma and lymphoma using Wilcoxon rank-sum test, chi-square test, and logistic regression. Receiver operating characteristic analysis identified the maximum standardized uptake value threshold most associated with thymoma. RESULTS: There was no association between tumor type and age group (P = .183) between those with thymoma versus anterior mediastinal lymphoma. Patients with thymoma were less likely to report B symptoms (P < .001). The median maximum standardized uptake value of thymoma and lymphoma differed dramatically: 4.35 versus 18.00 (P < .001). Maximum standardized uptake value was independently associated with tumor type on multivariable regression. On receiver operating characteristic analysis, lower maximum standardized uptake value was associated with thymoma. Maximum standardized uptake value less than 12.85 was associated with thymoma with 100.00% sensitivity and 88.89% positive predictive value. Maximum standardized uptake value less than 7.50 demonstrated 100.00% positive predictive value for thymoma. CONCLUSIONS: Positron emission tomography/computed tomography maximum standardized uptake value of resectable anterior mediastinal masses may help guide a direct surgery versus biopsy decision. Tumors with maximum standardized uptake value less than 7.50 are likely thymoma and thus perhaps appropriately resected without biopsy. Tumors with maximum standardized uptake value greater than 7.50 should be biopsied to rule out lymphoma. Lymphoma is likely with maximum standardized uptake value greater than 12.85.

Risk of adenocarcinoma in patients with a suspicious ground-glass opacity: a retrospective review.

Background: Both primary lung adenocarcinoma and benign processes can have a ground-glass opacity (GGO) appearance on imaging. This study evaluated the incidence of and risk factors for malignancy in a diverse cohort of patients who underwent resection of a GGO suspicious for lung cancer. Methods: All patients who underwent resection of a pulmonary nodule with a GGO component and suspected to be primary lung cancer at a single institution from 2001-2017 were retrospectively reviewed. Risk factors for malignancy were evaluated using multivariable logistic regression analysis that included nodule size, age, sex, and race as potential predictors. Results: The incidence of pulmonary adenocarcinoma in the 243 patients who met inclusion criteria was 86% (n=208). The most common pathologic findings in 35 patients with a benign pathology was granulomatous inflammation (n=14, 40%). Risk factors for adenocarcinoma in multivariable logistic regression were age [odds ratio (OR) 1.06, P=0.003], GGO size (OR 2.76, P<0.001), female sex (OR 4.47, P=0.002), and Asian race (OR 8.35, P=0.002). In this cohort, adenocarcinoma was found in 100% (44/44) of Asian females, 86% (25/29) of Asian males, 84% (98/117) of non-Asian females, and 77% (41/53) of non-Asian males. Conclusions: The likelihood of adenocarcinoma in lung nodules with a ground-glass component is influenced by sex and race. Asian females with a GGO have a much higher likelihood of having adenocarcinoma than men and non-Asians. This data can be used when deciding whether to pursue nodule resection or surveillance in a patient with a GGO.

Reconstructing codependent cellular cross-talk in lung adenocarcinoma using REMI.

Cellular cross-talk in tissue microenvironments is fundamental to normal and pathological biological processes. Global assessment of cell-cell interactions (CCIs) is not yet technically feasible, but computational efforts to reconstruct these interactions have been proposed. Current computational approaches that identify CCI often make the simplifying assumption that pairwise interactions are independent of one another, which can lead to reduced accuracy. We present REMI (REgularized Microenvironment Interactome), a graph-based algorithm that predicts ligand-receptor (LR) interactions by accounting for LR dependencies on high-dimensional, small-sample size datasets. We apply REMI to reconstruct the human lung adenocarcinoma (LUAD) interactome from a bulk flow-sorted RNA sequencing dataset, then leverage single-cell transcriptomics data to increase the cell type resolution and identify LR prognostic signatures among tumor-stroma-immune subpopulations. We experimentally confirmed colocalization of CTGF:LRP6 among malignant cell subtypes as an interaction predicted to be associated with LUAD progression. Our work presents a computational approach to reconstruct interactomes and identify clinically relevant CCIs.

Rationale and design of a mechanistic clinical trial of JAK inhibition to prevent ventilator-induced diaphragm dysfunction.

INTRODUCTION: Ventilator-induced diaphragm dysfunction (VIDD) is an important phenomenon that has been repeatedly demonstrated in experimental and clinical models of mechanical ventilation. Even a few hours of MV initiates signaling cascades that result in, first, reduced specific force, and later, atrophy of diaphragm muscle fibers. This severe, progressive weakness of the critical ventilatory muscle results in increased duration of MV and thus increased MV-associated complications/deaths. A drug that could prevent VIDD would likely have a major positive impact on intensive care unit outcomes. We identified the JAK/STAT pathway as important in VIDD and then demonstrated that JAK inhibition prevents VIDD in rats. We subsequently developed a clinical model of VIDD demonstrating reduced contractile force of isolated diaphragm fibers harvested after ∼7 vs ∼1 h of MV during a thoracic surgical procedure. MATERIALS AND METHODS: The NIH-funded clinical trial that has been initiated is a prospective, placebo controlled trial: subjects undergoing esophagectomy are randomized to receive 6 preoperative doses of the FDA-approved JAK inhibitor Tofacitinib (commonly used for rheumatoid arthritis) vs. placebo. The primary outcome variable will be the difference in the reduction that occurs in force generation of diaphragm single muscle fibers (normalized to their cross-sectional area), in the Tofacitinib vs. placebo subjects, over 6 h of MV. DISCUSSION: This trial represents a first-in-human, mechanistic clinical trial of a drug to prevent VIDD. It will provide proof-of-concept in human subjects whether JAK inhibition prevents clinical VIDD, and if successful, will support an ICU-based clinical trial that would determine whether JAK inhibition impacts clinical outcome variables such as duration of MV and mortality.

Impact of the Surgical Approach to Thymectomy Upon Complete Stable Remission Rates in Myasthenia Gravis: A Meta-analysis.

OBJECTIVES: To determine whether the available operative techniques for thymectomy in myasthenia gravis (MG) confer variable chances for achieving complete stable remission (CSR), we performed a meta-analysis of comparative studies of surgical approaches to thymectomy. METHODS: Meta-analysis was done of all studies providing comparative data on thymectomy approaches, with CSR reported and minimum 3-year mean follow-up. RESULTS: Twelve cohort studies and 1 randomized clinical trial, containing 1,598 patients, met entry criteria. At 3 years, CSR from MG was similar after video-assisted thoracoscopic (VATS) extended vs both basic (relative risk [RR] 1.00, p = 1.00, 95% confidence interval [CI] 0.39-2.58) and extended (RR 0.96, p = 0.74, 95% CI 0.72-1.27) transsternal approaches. CSR at 3 years was also similar after extended transsternal vs combined transcervical-subxiphoid (RR 1.08, p = 0.62, 95% CI 0.8-1.44) approaches. VATS extended approaches remained statistically equivalent to extended transsternal approaches through 9 years of follow-up (RR 1.51, p = 0.05, 95% CI 0.99-2.30). The only significant difference in CSR rate between a traditional open and a minimally invasive approach was seen at 10 years when the now-abandoned basic (non-sternum-lifting) transcervical approach was compared to the extended transsternal approach (RR 0.4, p = 0.01, 95% CI 0.2-0.8). CONCLUSIONS: A significant difference in the rate of CSR among various surgical approaches for thymectomy in MG was identified only at long-term follow-up and only between what might be considered the most aggressive approach (extended transsternal thymectomy) and the least aggressive approach (basic transcervical thymectomy). Extended minimally invasive approaches appear to have CSR rates equivalent to those of extended transsternal approaches and are therefore appropriate in the hands of experienced surgeons.

Cancer diagnoses and survival rise as 65-year-olds become Medicare-eligible.

BACKGROUND: A Medicare effect has been described to account for increased health care utilization occurring at the age of 65 years. The existence of such an effect in cancer care, where it would be most likely to reduce mortality, has been unclear. METHODS: Patients aged 61 to 69 years who were diagnosed with lung, breast, colon, or prostate cancer from 2004 to 2016 were identified with the Surveillance, Epidemiology, and End Results database and were dichotomized on the basis of eligibility for Medicare (61-64 vs 65-69 years). With age-over-age (AoA) percent change calculations, trends in cancer diagnoses and staging were characterized. After matching, uninsured patients who were 61 to 64 years old (pre-Medicare group) were compared with insured patients who were 65 to 69 years old (post-Medicare group) with respect to cancer-specific mortality. RESULTS: In all, 134,991 patients were identified with lung cancer, 175,558 were identified with breast cancer, 62,721 were identified with colon cancer, and 238,823 were identified with prostate cancer. The AoA growth in the number of cancer diagnoses was highest at the age of 65 years in comparison with all other ages within the decade for all 4 cancers (P < .01, P < .001, P < .01, and P < .001, respectively). In a comparison of diagnoses at the age of 65 years with those in the 61- to 64-year-old cohort, the greatest difference for all 4 cancers was seen in stage I. In matched analyses, the 5-year cancer-specific mortality was worse for lung (86.3% vs 78.5%; P < .001), breast (32.7% vs 11.0%; P < .001), colon (57.1% vs 35.6%; P < .001), and prostate cancer (16.9% vs 4.8%; P < .001) in the uninsured pre-Medicare group than the insured post-Medicare group. CONCLUSIONS: The age threshold of 65 years for Medicare eligibility is associated with more cancer diagnoses (particularly stage I), and this results in lower long-term cancer-specific mortality for all cancers studied. LAY SUMMARY: Contributing to the current debate regarding Medicare for all, this study shows that the expansion of Medicare would improve cancer outcomes for the near elderly.

Intracardiac paragangliomas: surgical approach and perioperative management.

Intracardiac paragangliomas most commonly arise from the left atrium and are often infiltrative and densely adherent to surrounding structures. Given their rarity, only scattered reports exist in the literature and standardized perioperative and surgical management is not well established. We describe a case of a 60-year-old woman with a mildly functioning intracardiac paraganglioma in which division of the superior vena cava improved exposure and enabled a complex limited resection. Further, we provide an overview of the diagnostic workup, perioperative medical management, surgical approach, and surveillance strategy in patients with these challenging tumors.

Paradoxical Motion on Sniff Test Predicts Greater Improvement Following Diaphragm Plication.

BACKGROUND: Diaphragm plication (DP) improves pulmonary function and quality of life for those with diaphragm paralysis or dysfunction. It is unknown whether differing degrees of diaphragm dysfunction as measured by sniff testing affect results after plication. METHODS: Patients who underwent minimally invasive DP from 2008 to 2019 were dichotomized based on sniff test results: paradoxical motion (PM) versus no paradoxical motion (NPM); the latter included normal, decreased, and no motion. Preoperative and postoperative pulmonary function testing (PFT) after DP was compared between groups. The impact of the diaphragm height index, a measure of diaphragm elevation, was also assessed. RESULTS: A total of 26 patients underwent preoperative sniff testing, DP, and postoperative PFT. Including all patients, DP resulted in a 17.8% ± 5.5% improvement in forced expiratory volume in 1 second (P < .001), a 14.4% ± 5.3% improvement in forced vital capacity (P < .001), and a 4.7% ± 4.6% improvement in the diffusing capacity of carbon monoxide (P = .539). There were greater improvements in the PM group (n = 16) compared with the NPM group (n = 10) for forced expiratory volume in 1 second (27.2% ± 6.0% versus 3.9% ± 6.2%; P = .017) and forced vital capacity (28.1% ± 5.3% versus -0.5% ± 3.3%; P = .001). There was no difference in the change in the diffusing capacity of carbon monoxide between groups. There were no differences between patients with PM and NPM in the postoperative course or complications. No value for diaphragm height index predicted improvement in PFT after DP. CONCLUSIONS: Patients with PM on sniff test have dramatically greater objective improvements in pulmonary function after plication compared with those without PM. Most patients without PM do not demonstrate improvement in standard PFT. Improvements in dyspnea require additional study.