Propensity score (PS) methods offer certain advantages over more traditional regression methods to control for confounding by indication in observational studies. Although multivariable regression ...models adjust for confounders by modelling the relationship between covariates and outcome, the PS methods estimate the treatment effect by modelling the relationship between confounders and treatment assignment. Therefore, methods based on the PS are not limited by the number of events, and their use may be warranted when the number of confounders is large, or the number of outcomes is small. The PS is the probability for a subject to receive a treatment conditional on a set of baseline characteristics (confounders). The PS is commonly estimated using logistic regression, and it is used to match patients with similar distribution of confounders so that difference in outcomes gives unbiased estimate of treatment effect. This review summarizes basic concepts of the PS matching and provides guidance in implementing matching and other methods based on the PS, such as stratification, weighting and covariate adjustment.
This primer for eighth edition staging of esophageal and esophagogastric epithelial cancers presents separate classifications for the clinical (cTNM), pathologic (pTNM), and postneoadjuvant ...pathologic (ypTNM) stage groups, which are no longer shared.
For pTNM, pT1 has been subcategorized as pT1a and pT1b for the subgrouping pStage I adenocarcinoma and squamous cell carcinoma. A new, simplified esophagus-specific regional lymph node map has been introduced. Undifferentiated histologic grade (G4) has been eliminated; additional analysis is required to expose histopathologic cell type. Location has been removed as a category for pT2N0M0 squamous cell cancer. The definition of the esophagogastric junction has been revised. ypTNM stage groups are identical for both histopathologic cell types, unlike those for cTNM and pTNM.
The 8th edition of the American Joint Committee on Cancer (AJCC) staging of epithelial cancers of the esophagus and esophagogastric junction (EGJ) presents separate classifications for clinical ...(cTNM), pathologic (pTNM), and postneoadjuvant (ypTNM) stage groups. Histopathologic cell type markedly affects survival of clinically and pathologically staged patients, requiring separate groupings for each cell type, but ypTNM groupings are identical for both cell types. Clinical categories, typically obtained by imaging with minimal histologic information, are limited by resolution of each method. Strengths and shortcomings of clinical staging methods should be recognized. Complementary cytology or histopathology findings may augment imaging and aid initial treatment decision-making. However, prognostication using clinical stage groups remains coarse and inaccurate compared with pTNM. Pathologic staging is losing its relevance for advanced-stage cancer as neoadjuvant therapy replaces esophagectomy alone. However, it remains relevant for early-stage cancers and as a staging and survival reference point. Although pathologic stage could facilitate decision-making, its use to direct postoperative adjuvant therapy awaits more effective treatment. Prognostication using pathologic stage groups is the most refined of all classifications. Postneoadjuvant staging (ypTNM) is introduced by the AJCC but not adopted by the Union for International Cancer Control (UICC). Drivers of this addition include absence of equivalent pathologic (pTNM) categories for categories peculiar to the postneoadjuvant state (ypT0N0-3M0 and ypTisN0-3M0), dissimilar stage group compositions, and markedly different survival profiles. Thus, prognostication is specific for patients undergoing neoadjuvant therapy. The role of ypTNM classification in additional treatment decision-making is currently limited. Precision cancer care advances are necessary for this information to be clinically useful.
Abstract
Aims
The Valve Academic Research Consortium (VARC), founded in 2010, was intended to (i) identify appropriate clinical endpoints and (ii) standardize definitions of these endpoints for ...transcatheter and surgical aortic valve clinical trials. Rapid evolution of the field, including the emergence of new complications, expanding clinical indications, and novel therapy strategies have mandated further refinement and expansion of these definitions to ensure clinical relevance. This document provides an update of the most appropriate clinical endpoint definitions to be used in the conduct of transcatheter and surgical aortic valve clinical research.
Methods and results
Several years after the publication of the VARC-2 manuscript, an in-person meeting was held involving over 50 independent clinical experts representing several professional societies, academic research organizations, the US Food and Drug Administration (FDA), and industry representatives to (i) evaluate utilization of VARC endpoint definitions in clinical research, (ii) discuss the scope of this focused update, and (iii) review and revise specific clinical endpoint definitions. A writing committee of independent experts was convened and subsequently met to further address outstanding issues. There were ongoing discussions with FDA and many experts to develop a new classification schema for bioprosthetic valve dysfunction and failure. Overall, this multi-disciplinary process has resulted in important recommendations for data reporting, clinical research methods, and updated endpoint definitions. New definitions or modifications of existing definitions are being proposed for repeat hospitalizations, access site-related complications, bleeding events, conduction disturbances, cardiac structural complications, and bioprosthetic valve dysfunction and failure (including valve leaflet thickening and thrombosis). A more granular 5-class grading scheme for paravalvular regurgitation (PVR) is being proposed to help refine the assessment of PVR. Finally, more specific recommendations on quality-of-life assessments have been included, which have been targeted to specific clinical study designs.
Conclusions
Acknowledging the dynamic and evolving nature of less-invasive aortic valve therapies, further refinements of clinical research processes are required. The adoption of these updated and newly proposed VARC-3 endpoints and definitions will ensure homogenous event reporting, accurate adjudication, and appropriate comparisons of clinical research studies involving devices and new therapeutic strategies.
Graphical Abstract
Increased life expectancy and younger patients' desire to avoid lifelong anticoagulation requires a better understanding of bioprosthetic valve failure. This study evaluates risk factors associated ...with explantation for structural valve deterioration (SVD) in a long-term series of Carpentier-Edwards PERIMOUNT aortic valves (AV).
From June 1982 to January 2011, 12,569 patients underwent AV replacement with Edwards Lifesciences Carpentier-Edwards PERIMOUNT stented bovine pericardial prostheses, models 2700PM (n = 310) or 2700 (n = 12,259). Mean age was 71 ± 11 years (range, 18 to 98 years). 93% had native AV disease, 48% underwent concomitant coronary artery bypass grafting, and 26% had additional valve surgery. There were 81,706 patient-years of systematic follow-up data available for analysis. Demographics, intraoperative variables, and 27,386 echocardiographic records were used to identify risks for explant for SVD and assess longitudinal changes in transprosthesis gradients using time-varying covariable analyses.
Three hundred fifty-four explants were performed, with 41% related to endocarditis and 44% to SVD. Actuarial estimates of explant for SVD at 10 and 20 years were 1.9% and 15% overall, respectively, and in patients younger than 60 years, 5.6% and 46%, respectively. Younger age (p < 0.0001), lipid-lowering drugs (p = 0.002), prosthesis-patient mismatch (p = 0.001), and higher postoperative peak and mean AV gradients were associated with explant for SVD (p < 0.0001). The effect of gradient on SVD was greatest in patients younger than 60 years.
Durability of the Carpentier-Edwards PERIMOUNT aortic valve is excellent even in younger patients. Explant for SVD is related to gradient at implantation, especially in younger patients. Strategies to reduce early postoperative AV gradients, such as root enlargement or more efficient prostheses, should be considered.
Commentary: Tell me a story Blackstone, Eugene H.
The Journal of thoracic and cardiovascular surgery,
July 2022, 2022-07-00, 20220701, Letnik:
164, Številka:
1
Journal Article
Abstract Objective To review the published literature using propensity scoring, describe shortcomings in the use of this technique, and provide conceptual background for understanding and correctly ...implementing studies that use propensity matching. Methods We survey the published statistical literature and make recommendations for a set of standard criteria for studies that use propensity matching. We evaluated adherence to these criteria in recent publications in the Journal of Thoracic and Cardiovascular Surgery and determined how well the standards were applied. Results We found that studies that use propensity matching are rarely documented well enough to be convincing in their results. When documentation is available, statistical shortcomings are common. Conclusions Improved statistical practice is needed when using propensity scoring. This article suggests standard criteria for using this method in Journal publications.
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