Defining "the elderly" undergoing major gastrointestinal resections: receiver operating characteristic analysis of a large ACS-NSQIP cohort.

Objective: "The elderly" is an often used but poorly defined descriptor of surgical patients. Investigators have used varying subjectively determined age cutoffs to report outcomes in the elderly. We set out to use objective outcomes data to determine the "at-risk" elderly population.

Validation of new york operative mortality risk score for valve and valve/coronary artery bypass grafting operations.

Background: New York (NY) valve and valve/coronary artery bypass grafting (CABG) mortality risk models, developed from operations performed in 2007 to 2009, have just been published. These models were validated using NY data from 2004 to 2006. The authors stated that their models "should also be validated by testing them against non-New York populations.

Effect of hospital culture on blood transfusion in cardiac procedures.

Background: In our effort to reduce the use of blood products in cardiac operations in a health care system, we noted variations in transfusion practices among facilities. Interestingly, surgeons practicing at the same hospital had similar transfusion rates. We sought to quantitate the contribution of hospital influence on individual surgeons' transfusion practices.

Durability of pericardial versus porcine bioprosthetic heart valves.

Objectives: To compare the probability, and modes, of explantation for Carpentier-Edwards pericardial versus porcine valves.

Methods: Our porcine series began in 1974 and our pericardial series in 1991, with annual prospective follow-up. We used the Kaplan-Meier method and Cox regression for estimation and analysis of patient mortality, and the cumulative incidence function and competing risks regression for estimation and analysis of valve durability.

Long-term results after Carpentier-Edwards pericardial aortic valve implantation, with attention to the impact of age.

Background: The purpose of this study was to determine long-term patient survival and valve durability for Carpentier-Edwards pericardial valves (Edwards Lifesciences) implanted in the aortic position, with specific attention to the impact of patient age.

Methods: We performed a retrospective cohort study of 2168 patients who underwent implantation of a Carpentier-Edwards pericardial aortic valve between 1991 and 2008. The mean follow-up time was 4.

Using Society of Thoracic Surgeons risk models for risk-adjusting cardiac surgery results.

The Society of Thoracic Surgeons National Adult Cardiac Surgery Database (STS NCD) has become the national benchmark for cardiac surgery reporting. Several important aspects of its risk-adjustment reporting are discussed, with special emphasis on using the reported individual STS risk scores for analysis and evaluation: (1) Different risk models are used in different STS NCD versions. (2) STS calibrates risk scores annually to make the annual predicted rates equal the observed rates.

What is the value of a p value?

Successful publication of a research study usually requires a small p value, typically p < 0.05. Many clinicians believe that a p value represents the probability that the null hypothesis is true, so that a small p value means the null hypothesis must be false.

Estimated glomerular filtration rate and renal function.

Glomerular filtration rate (GFR) is an important clinical indicator of kidney function. It can be used as an independent predictor of long-term survival after cardiac surgery. Definition, methods of measurement, and corrected value by body surface area are briefly introduced in this paper.

Using the National Death Index to validate the noninformative censoring assumption of survival estimation.

Background: In survival analysis, a patient who is missing complete follow-up is included in the analysis as a censored observation. The analysis makes the assumption that the censoring is noninformative; that is, that a censored patient has the same risk of death as those who have complete follow-up. We tested this assumption in a large, long-term follow-up study.

Measuring follow-up completeness.

Completeness of follow-up is often used as a measure of the quality of follow-up, but the method used to compute it is often not declared. An ideal measure should be based on follow-up years instead of patients. Clark, Altman, and De Stavola proposed such a measure, called "C", which is the percentage of the maximum possible follow-up years, as of a given date, that has actually been accounted for or observed.

Actual and actuarial probabilities of competing risks: apples and lemons.

The probability of a type of failure that is not inevitable, but can be precluded by other events such as death, is given by the cumulative incidence function. In cardiac research articles, it has become known as the actual probability, in contrast to the actuarial methods of estimation, usually implemented by the Kaplan-Meier (KM) estimate. Unlike cumulative incidence, KM attempts to predict what the latent failure probability would be if death were eliminated.

Time-related risk of the St. Jude Silzone heart valve.

Objective: The St. Jude Medical Silzone heart valve had a silver-impregnated sewing ring designed to reduce the incidence of prosthetic valve endocarditis. Recruitment to the randomized AVERT study comparing Silzone valves with non-Silzone Control valves was stopped because of an increased risk of reoperation for paravalvular leak, but patient follow-up continues.

Median sternotomy versus thoracotomy to resect primary lung cancer: analysis of 815 cases.

Background: We sought to determine if median sternotomy (MS) is an equivalent incision to thoracotomy (TH) in the treatment of primary pulmonary carcinoma.

Methods: We followed 801 patients undergoing 815 operations for primary lung carcinoma in a computer registry; 447 had MS, 368 had TH.

Results: Both groups were similar in preoperative risk assessment.

Artificial heart valves.

This overview of heart valve prostheses is based on a current review of clinical reports and focuses on the major complications that characterize long-term valve performance: thromboembolism, thrombosis, anti-coagulant-related bleeding, and structural failure.