Mid-term Survival After Abdominal Aortic Aneurysm Surgery Predicted by Cardiopulmonary Exercise Testing

Abstract

6-month group. Overall, fatal and nonfatal VTE during and after treatment occurred in 8% of those receiving 3 months of anticoagulation (n ϭ 31) and in 8% of those receiving 6 months anticoagulation (n ϭ 29; P ϭ .80; 95% confidence interval [CI] difference, -3.1% to 4.7%). No patients in either group had a fatal hemorrhage during treatment, but there were eight major hemorrhages in those treated for 6 months and none in those treated for 3 months (P ϭ .008; 95% CI, -3.5% to -0.7%). Adverse events occurred in 8% of the patients receiving 3 months of anticoagulation (n ϭ 31) and in 9% of the patients receiving 6 months of anticoagulation (n ϭ 35; P ϭ .79, 95% CI -4.9% to 3.2%).Comment: The data with regard to the hard end points in this study-death from VTE or major hemorrhage-are likely reliable. The data with respect to recurrence, extension, or failure to resolve VTE are likely highly unreliable because they were derived from review forms completed by clinicians at each individual site, without specific requirements for imaging during follow-up. Indeed, the idea that the DVT resolved in Ͼ95% of the patients treated with oral anticoagulation is completely disparate with regard to the findings of serial imaging studies in patients with DVT. The authors also provide no information about possible postphlebitic syndrome in their patients. Follow-up is too short for such an analysis. Overall, the study indicates no difference in death from VTE with 3 or 6 months of anticoagulation in a patient with VTE and unidentified risk factors. The data are not sufficient to conclude that there is no difference in recurrence of VTE with the two treatment paradigms. Heritability of Platelet Responsiveness to Aspirin in ActivationPathways Directly and Indirectly Related to Cyclooxygenase-1 Faraday N, Yanek LR, Mathias R, et al. Circulation 2007;115:2490-6.Conclusion: There is a genetic basis to variability in residual platelet function after aspirin exposure.Summary: It is known that the inability of aspirin to suppress platelet function can be associated with future risk of myocardial infarction, stroke, and cardiovascular death. The authors sought to determine if there was genetic variation that could be linked to insufficient aspirin responsiveness.Aspirin responsiveness was assessed in 1880 asymptomatic patients. The mean age was 44 Ϯ 13 years, and 58% were women. Patients were recruited from 309 white and 208 black families with premature coronary heart disease. Platelet function was determined ex vivo before and after ingestion of aspirin (81 mg/d for 2 weeks). Platelet function was determined with a panel of tests assessing platelet activation in pathways indirectly and directly related to cyclooxygenase-1 (COX-1). Multivariable regression analysis was also used to determine the proportion of phenotypic variance related to coronary heart disease risk factor covariates.Arachidonic acid-induced thromboxane B 2 production was inhibited by Ͼ99% with aspirin (P Ͻ .0001). Platelet activation by pathways indirectly related to COX-1...

Cardiopulmonary exercise testing for the evaluation of perioperative risk in non-cardiopulmonary surgery

“…To maximise our ability to identify high risk patients before surgery, it is likely that CPET results will ultimately be combined with alternative methods of risk stratification which identify other aspects of perioperative risk. Indeed, studies included in the current review identified that CPET variables could be used in conjunction with the RCRI and the VSAQ to enhance the capacity to predict perioperative risk 8 14. However, the capacity of these combinations of variables to stratify risk has not been validated using different populations and therefore their use is not warranted in the clinical setting at this time.…”

“…However, the optimal predictor of high risk appears to differ between surgery types, with AT shown to be the best indicator of higher risk patients for major intra-abdominal surgery, ${\dot{\mathrm{normalV}}\mathrm{O}}_2$ peak for bariatric surgery, and ${\dot{\mathrm{V}}}_{\text{E}}/{\dot{\mathrm{normalV}}\mathrm{CO}}_2$ for AAA repair surgery (table 2). 8 9 12 14 Furthermore, it appears that CPET is of limited use for risk stratification before an oesophagectomy 19. Variation in the type and strength of the association between CPET variable and outcome in different types of surgery is likely to be due to variation in the relative importance of different factors predisposing to adverse outcome.…”

“…Of the many physiological variables determined during CPET, in the preoperative assessment setting, three have been shown to help identify high risk patients: ${\dot{\mathrm{normalV}}\mathrm{O}}_2$ peak/max,12 anaerobic threshold (AT),5 8 9 13 and ventilatory equivalent for carbon dioxide $({\dot{\mathrm{V}}}_{\text{E}}/{\dot{\mathrm{normalV}}\mathrm{CO}}_2)$ 9 14. Consequently, these three variables are used most frequently to stratify risk for non-cardiopulmonary surgery 6.…”

“…In this study, a ${\dot{\mathrm{normalV}}\mathrm{O}}_2$ peak <20 ml/kg/min was tentatively proposed as a marker to identify patients at increased perioperative risk, despite no differences in ${\dot{\mathrm{normalV}}\mathrm{O}}_2$ peak being present between patients with or without postoperative complications. Following this, Carlisle and Swart retrospectively studied the association between four CPET markers (${\dot{\mathrm{normalV}}\mathrm{O}}_2$ peak, AT, ${\dot{\mathrm{V}}}_{\text{E}}/{\dot{\mathrm{normalV}}\mathrm{CO}}_2$, and ${\dot{\mathrm{V}}}_{\text{E}}/{\dot{\mathrm{normalV}}\mathrm{O}}_2$), four other risk stratification methods (RCRI, POSSUM, Simplified Acute Physiology Score (SAPS) II, and the Acute Physiology And Chronic Health Evaluation (APACHE) II) and all cause mortality following AAA repair 14. The study differs from other CPET articles in non-cardiopulmonary surgery, in that the mortality was not only measured in the initial postoperative period, but also up to a median of 35 months post-surgery, termed mid-term.…”

“…Based on the results from Carlise and Swart, ${\dot{\mathrm{V}}}_{\text{E}}/{\dot{\mathrm{normalV}}\mathrm{CO}}_2$ is the optimal CPET variable to indicate high risk patients undergoing an AAA repair 14. However, analysis was not conducted to identify the classification accuracy of this variable; therefore it is not possible to know the extent to which it can predict those at greater risk of mortality following surgery.…”