Society Of Thoracic Surgeons Guidelines Research Articles

Antiplatelet Drugs: Mechanisms and Risks of Bleeding Following Cardiac Operations

Preoperative antiplatelet drug use is common in patients undergoing coronary artery bypass grafting (CABG). The impact of these drugs on bleeding and blood transfusion varies. We hypothesize that review of available evidence regarding drug-related bleeding risk, underlying mechanisms of platelet dysfunction, and variations in patient response to antiplatelet drugs will aid surgeons as they assess preoperative risk and attempt to limit perioperative bleeding. The purpose of this review is to (1) examine the role that antiplatelet drugs play in excessive postoperative blood transfusion, (2) identify possible mechanisms to explain patient response to antiplatelet drugs, and (3) formulate a strategy to limit excessive blood product usage in these patients. We reviewed available published evidence regarding bleeding risk in patients taking preoperative antiplatelet drugs. In addition, we summarized our previous research into mechanisms of antiplatelet drug-related platelet dysfunction. Aspirin users have a slight but significant increase in blood product usage after CABG (0.5 U of nonautologous blood per treated patient). Platelet adenosine diphosphate (ADP) receptor inhibitors are more potent antiplatelet drugs than aspirin but have a half-life similar to aspirin, around 5 to 10 days. The American Heart Association/American College of Cardiology and the Society of Thoracic Surgeons guidelines recommend discontinuation, if possible, of ADP inhibitors 5 to 7 days before operation because of excessive bleeding risk, whereas aspirin should be continued during the entire perioperative period in most patients. Individual variability in response to aspirin and other antiplatelet drugs is common with both hyper- and hyporesponsiveness seen in 5 to 25% of patients. Use of preoperative antiplatelet drugs is a risk factor for increased perioperative bleeding and blood transfusion. Point-of-care tests can identify patients at high risk for perioperative bleeding and blood transfusion, although these tests have limitations. Available evidence suggests that multiple blood conservation techniques benefit high-risk patients taking antiplatelet drugs before operation. Guidelines for patients who take aspirin and/or thienopyridines before cardiac procedures include some or all of the following: (1) preoperative identification of high-risk patients using point-of-care testing; (2) withdrawal of aspirin or other antiplatelet drugs for a few days and delay of operation in patients at high risk for bleeding if clinical circumstances permit; (3) selective perioperative use of evidence-based blood conservation interventions (e.g., short-course erythropoietin, off-pump procedures, and use of intraoperative blood conservation techniques), especially in high-risk patients; and (4) platelet transfusions if clinical bleeding occurs.

Can We Predict Pulmonary Complications After Thoracic Surgery?

Can We Predict Pulmonary Complications After Thoracic Surgery?

The use of spirometry testing prior to cardiac surgery may impact the Society of Thoracic Surgeons risk prediction score: A prospective study in a cohort of patients at high risk for chronic lung disease

Chronic lung disease is a significant comorbidity in patients undergoing cardiac surgery. Chronic lung disease is currently being classified and reported to the Society of Thoracic Surgeons database by using either clinical interview or spirometric testing. We sought to compare the chronic lung disease classification captured by the 2 methods. We performed a prospectively designed study in which patients presenting for cardiac surgery, excluding emergent patients, were screened for a history of asthma, a history of 10 or more pack-years of smoking, a persistent cough, and the use of oxygen. Each selected patient underwent spirometry. The presence and severity of chronic lung disease was coded per Society of Thoracic Surgeons guidelines by using the 2 methods of clinical report and spirometric results. The chronic lung disease classifications were compared, and differences were determined by using concordance and discordance rates. The results were then used to construct Society of Thoracic Surgeons-predicted risk models. The discordant rate was 39.1%, with underestimation of the severity of chronic lung disease in 94% of misclassified patients. This affected the Society of Thoracic Surgeons-predicted risk models for prolonged ventilation, morbidity/mortality, and mortality by increasing the predicted risk when spirometry was used for morbidity/mortality by an average of 1.5 +/- 1.2 percentage points (P < .001) and prolonged ventilation time by an average of 1.3 +/- 1.4 percentage points (P < .001). The use of patient history for symptoms, medication, and/or oxygen use as the only method to determine chronic lung disease for this subgroup of patients led to underreporting of chronic lung disease and underestimation of the risk for adverse outcomes. Therefore data submission to the Society of Thoracic Surgeons database should be designed to capture and correct for potential bias in the definition of chronic lung disease because the rate of spirometry in different centers in defining chronic lung disease is not regulated.

Durability of the hancock MO bioprosthesis compared with standard aortic valve bioprostheses

To compare the durability of the Hancock modified orifice (Hancock MO, model 250 [H-MO]) valve with two other commonly used standard aortic valve bioprostheses, a cohort of 1,602 patients undergoing aortic valve replacement using porcine valves between 1971 and 1990 (excluding simultaneous mitral valve replacement) was analyzed retrospectively using Cox model multivariate techniques. Five hundred sixty-one patients received a composite H-MO valve, 652 received a standard Hancock model 242 (H) valve, and 389 received a Carpentier-Edwards model 2625 (C-E) valve. Mean age was 60 +/- 15 years (+/- 1 standard deviation) (71% male). Follow-up (10,247 patient-years) extended to 15 years and was 97% complete. The main focus of this study was bioprosthetic durability, using The American Association for Thoracic Surgery/The Society of Thoracic Surgeons guidelines to define structural valve deterioration (SVD). Multivariate analysis revealed that (younger) age (p < 10(-5), liver disease (p = 0.02), and 1981 to 1985 operative period (p = 0.012) were the only significant, independent predictors of SVD. In concordance with previous reports, the SVD freedom estimate was greater than 90% at 15 years for patients older than 70 years of age. Hepatic dysfunction had an adverse effect on SVD (estimated freedom from event at 10 years was 34 +/- 17% [standard error of mean] versus 78 +/- 2% for those without liver disease), but this affected only 3% of patients. Interestingly, one operative period (1981 to 1985) was associated with a slightly higher risk of SVD compared to the three other 5-year time windows. Valve type did not emerge as a significant risk factor for SVD.(ABSTRACT TRUNCATED AT 250 WORDS)