Targeted proteomics and metabolomics for biomarker discovery in abdominal aortic aneurysm and post-EVAR sac volume.

BACKGROUND AND AIMS: Abdominal aortic aneurysm (AAA) patients undergo uniform surveillance programs both leading up to, and following surgery. Circulating biomarkers could play a pivotal role in individualizing surveillance. We applied a multi-omics approach to identify relevant biomarkers and gain pathophysiological insights. MATERIALS AND METHODS: In this cross-sectional study, 108 AAA patients and 200 post-endovascular aneurysm repair (post-EVAR) patients were separately investigated. We performed partial least squares regression and ingenuity pathway analysis on circulating concentrations of 96 proteins (92 Olink Cardiovascular-III panel, 4 ELISA-assays) and 199 metabolites (measured by LC-TQMS), and their associations with CT-based AAA/sac volume. RESULTS: The median (25th-75th percentile) maximal diameter was 50.0 mm (46.0, 53.0) in the AAA group, and 55.4 mm (45.0, 64.2) in the post-EVAR group. Correcting for clinical characteristics in AAA patients, the aneurysm volume Z-score differed 0.068 (95 %CI: (0.042, 0.093)), 0.066 (0.047, 0.085) and -0.051 (-0.064, -0.038) per Z-score valine, leucine and uPA, respectively. After correcting for clinical characteristics and orthogonalization in the post-EVAR group, the sac volume Z-score differed 0.049 (0.034, 0.063) per Z-score TIMP-4, -0.050 (-0.064, -0.037) per Z-score LDL-receptor, -0.051 (-0.062, -0.040) per Z-score 1-OG/2-OG and -0.056 (-0.066, -0.045) per Z-score 1-LG/2-LG. CONCLUSIONS: The branched-chain amino acids and uPA were related to AAA volume. For post-EVAR patients, LDL-receptor, monoacylglycerols and TIMP-4 are potential biomarkers for sac volume. Additionally, distinct markers for sac change were identified.

Postoperative myocardial injury phenotypes and self-reported disability in patients undergoing noncardiac surgery: a multicentre observational study.

BACKGROUND: Postoperative myocardial injury (PMI) comprises a spectrum of mechanisms resulting in troponin release. The impact of different PMI phenotypes on postoperative disability remains unknown. METHODS: This was a multicentre prospective cohort study including patients aged ≥50 yr undergoing elective major noncardiac surgery. Patients were stratified in five groups based on the occurrence of PMI and clinical information on postoperative adverse events: PMI classified as myocardial infarction (MI; according to fourth definition), PMI plus adverse event other than MI, clinically silent PMI (PMI without adverse events), adverse events without PMI, and neither PMI nor an adverse event (reference). The primary endpoint was 6-month self-reported disability (assessed by WHO Disability Assessment Schedule 2.0 [WHODAS]). Disability-free survival was defined as WHODAS ≤16%. RESULTS: We included 888 patients of mean age 69 (range 53-91) yr, of which 356 (40%) were women; 151 (17%) patients experienced PMI, and 625 (71%) experienced 6-month disability-free survival. Patients with PMI, regardless of its phenotype, had higher preoperative disability scores than patients without PMI (difference in WHODAS; ß: 3.3, 95% confidence interval [CI]: 0.5-6.2), but scores remained stable after surgery (ß: 1.2, 95% CI: -3.2-5.6). Before surgery, patients with MI (n=36, 4%) were more disabled compared with patients without PMI and no adverse events (ß: 5.5, 95% CI: 0.3-10.8). At 6 months, patients with MI and patients without PMI but with adverse events worsened in disability score (ß: 11.2, 95% CI: 2.3-20.2; ß: 8.1, 95% CI: 3.0-13.2, respectively). Patients with clinically silent PMI did not change in disability score at 6 months (ß: 1.39, 95% CI: -4.50-7.29, P=0.642). CONCLUSIONS: Although patients with postoperative myocardial injury had higher preoperative self-reported disability, disability scores did not change at 6 months after surgery. However, patients experiencing myocardial infarction worsened in disability score after surgery.

How We Would Treat Our Own Thoracoabdominal Aortic Aneurysm.

This manuscript is intended to provide a comprehensive review of the current state of knowledge on endovascular repair of thoracoabdominal aortic aneurysms (TAAAs). The management of these complex aneurysms requires an interdisciplinary and patient-specific approach in high-volume centers. An index case is used to discuss the diagnosis and treatment of a patient undergoing fenestrated-branched endovascular aneurysm repair for a TAAA.

Prediction, prognosis, and professionalism in perioperative medicine.

Guidelines provide a framework to take better care of our patients. They are published by different professional groups and are based on all the research done for us by hardworking colleagues. Compiling a guideline is an enormous amount of work and is generally done with the utmost care. However, recommendations often require a subjective interpretation of published research, where personal and academic interests can influence the outcome. We discuss two recently published guidelines on perioperative cardiovascular assessment that led to different conclusions on some important areas of patient care.

Circulating biomarkers of cardiovascular disease are related to aneurysm volume in abdominal aortic aneurysm.

BACKGROUND: Surveillance programs in abdominal aortic aneurysms (AAA) are mainly based on imaging and leave room for improvement to timely identify patients at risk for AAA growth. Many biomarkers are dysregulated in patients with AAA, which fuels interest in biomarkers as indicators of disease progression. We examined associations of 92 cardiovascular disease (CVD)-related circulating biomarkers with AAA and sac volume. METHODS: In a cross-sectional analysis, we separately investigated (1) 110 watchful waiting (WW) patients (undergoing periodic surveillance imaging without planned intervention) and (2) 203 patients after endovascular aneurysm repair (EVAR). The Cardiovascular Panel III (Olink Proteomics AB, Sweden) was used to measure 92 CVD-related circulating biomarkers. We used cluster analyses to investigate protein-based subphenotypes, and linear regression to examine associations of biomarkers with AAA and sac volume on CT scans. RESULTS: Cluster analyses revealed two biomarker-based subgroups in both WW and EVAR patients, with higher levels of 76 and 74 proteins, respectively, in one subgroup versus the other. In WW patients, uPA showed a borderline significant association with AAA volume. Adjusting for clinical characteristics, there was a difference of -0.092 (-0.148, -0.036) loge mL in AAA volume per SD uPA. In EVAR patients, after multivariable adjustment, four biomarkers remained significantly associated with sac volume. The mean effects on sac volume per SD difference were: LDLR: -0.128 (-0.212, -0.044), TFPI: 0.139 (0.049, 0.229), TIMP4: 0.110 (0.023, 0.197), IGFBP-2: 0.103 (0.012, 0.194). CONCLUSION: LDLR, TFPI, TIMP4, and IGFBP-2 were independently associated with sac volume after EVAR. Subgroups of patients with high levels of the majority of CVD-related biomarkers emphasize the intertwined relationship between AAA and CVD.ClinicalTrials.gov Identifier: NCT03703947.

Intraoperative hypotension in noncardiac surgery patients with chronic beta-blocker therapy: A matched cohort analysis.

STUDY OBJECTIVE: To explore the incidence of intraoperative hypotension in patients with chronic beta-blocker therapy, expressed as time spent, area and time-weighted average under predefined mean arterial pressure thresholds. DESIGN: Retrospective analysis of a prospective observational cohort registry. SETTING: Patients ≥60 years undergoing intermediate- to high-risk noncardiac surgery with routine postoperative troponin measurements on the first three days after surgery. PATIENTS: 1468 matched sets of patients (1:1 ratio with replacement) with and without chronic beta-blocker treatment. INTERVENTIONS: None. MEASUREMENTS: The primary outcome was the exposure to intraoperative hypotension in beta-blocker users vs. non-users. Time spent, area and time-weighted average under predefined mean arterial pressure thresholds (55-75 mmHg) were calculated to express the duration and severity of exposure. Secondary outcomes included incidence of postoperative myocardial injury and thirty-day mortality, myocardial infarction (MI) and stroke. Furthermore, analyses for patient subgroup and beta-blocker subtype were conducted. MAIN RESULTS: In patients with chronic beta-blocker therapy, no increased exposure to intraoperative hypotension was observed for all characteristics and thresholds calculated (all P > .05). Beta-blocker users had lower heart rate before, during and after surgery (70 vs. 74, 61 vs. 65 and 68 vs. 74 bpm, all P < .001, respectively). Postoperative myocardial injury (13.6% vs. 11.6%, P = .269) and thirty-day mortality (2.5% vs. 1.4%, P = .055), MI (1.4% vs. 1.5%, P = .944) and stroke (1.0% vs 0.7%, P =  .474) rates were comparable. The results were consistent in subtype and subgroup analyses. CONCLUSIONS: In this matched cohort analysis, chronic beta-blocker therapy was not associated with increased exposure to intraoperative hypotension in patients undergoing intermediate- to high-risk noncardiac surgery. Furthermore, differences in patient subgroups and postoperative adverse cardiovascular events as a function of treatment regimen could not be demonstrated.

'If you don't take a temperature, you can't find a fever': relevance to continuous arterial pressure monitoring.

Intraoperative hypotension is common and is associated with adverse postoperative outcomes. A substantial fraction of all perioperative hypotension occurs shortly after induction of anaesthesia and before the procedure begins. Arterial pressure monitoring is usually intermittent in this period, with a risk of missing significant hypotensive events. Continuous blood pressure monitoring might help reduce hypotension. There are now strong arguments that if an arterial line is indicated, it should be placed before induction of anaesthesia to obtain maximal benefit.

Immediate postoperative high-sensitivity troponin T concentrations and long-term patient-reported health-related quality of life: A prospective cohort study.

BACKGROUND: Myocardial injury after noncardiac surgery is associated with mortality and major adverse postoperative cardiovascular events. The effect of postoperative troponin concentrations on patient-reported health-related quality of life (HRQoL) is unknown. OBJECTIVE: The study examined the association between immediate postoperative troponin concentrations and self-reported HRQoL 1 year after surgery. DESIGN: Prospective cohort study. SETTING: Single-centre tertiary care hospital in the Netherlands between July 2012 and 2015. PATIENTS: Patients aged at least 60 years undergoing moderate and major noncardiac surgery. INTERVENTION: None. MAIN OUTCOME MEASURES: HRQoL total score was assessed with the EuroQol five-dimensional questionnaire. Tobit regression analysis was used to determine the association between postoperative troponin concentrations and 1-year HRQoL. Peak high-sensitivity troponin T values were divided into four categories: less than 14, 14 to 49, 50 to 149 and at least 150 ng l. RESULTS: A total of 3085 patients with troponin measurements were included. 2634 (85.4%) patients were alive at 1-year follow-up of whom 1297 (49.2%) returned a completed questionnaire. The median score for HRQoL was 0.82 (0.85, 0.81, 0.77 and 0.71 per increasing troponin category). Multivariable analysis revealed betas of -0.06 [95% confidence interval (CI) -0.09 to -0.02], -0.11 (95% CI -0.18 to -0.04) and -0.18 (95% CI -0.29 to -0.07) for troponin levels of 14 to 49, 50 to 149 and at least 150 ng l when compared with values less than 14 ng l. Other independent predictors for lower HRQoL were chronic obstructive pulmonary disease, female sex, peripheral arterial disease and increasing age. CONCLUSION: Higher levels of postoperative troponin measured immediately after surgery were independently associated with lower self-reported HRQoL total score at 1-year follow-up.

Postoperative Hypotension after Noncardiac Surgery and the Association with Myocardial Injury.

BACKGROUND: Intraoperative hypotension has been associated with postoperative morbidity and early mortality. Postoperative hypotension, however, has been less studied. This study examines postoperative hypotension, hypothesizing that both the degree of hypotension severity and longer durations would be associated with myocardial injury. METHODS: This single-center observational cohort was comprised of 1,710 patients aged 60 yr or more undergoing intermediate- to high-risk noncardiac surgery. Frequent sampling of hemodynamic monitoring on a postoperative high-dependency ward during the first 24 h after surgery was recorded. Multiple mean arterial pressure (MAP) absolute thresholds (50 to 75 mmHg) were used to define hypotension characterized by cumulative minutes, duration, area, and time-weighted-average under MAP. Zero time spent under a threshold was used as the reference group. The primary outcome was myocardial injury (a peak high-sensitive troponin T measurement 50 ng/l or greater) during the first 3 postoperative days. RESULTS: Postoperative hypotension was common, e.g., 2 cumulative hours below a threshold of 60 mmHg occurred in 144 (8%) patients while 4 h less than 75 mmHg occurred in 824 (48%) patients. Patients with myocardial injury had higher prolonged exposures for all characterizations. After adjusting for confounders, postoperative duration below a threshold of 75 mmHg for more than 635 min was associated with myocardial injury (adjusted odds ratio, 2.68; 95% CI, 1.46 to 5.07, P = 0.002). Comparing multiple thresholds, cumulative durations of 2 to 4 h below a MAP threshold of 60 mmHg (adjusted odds ratio, 3.26; 95% CI, 1.57 to 6.48, P = 0.001) and durations of more than 4 h less than 65 mmHg (adjusted odds ratio, 2.98; 95% CI, 1.78 to 4.98, P < 0.001) and 70 mmHg (adjusted odds ratio, 2.18; 95% CI, 1.37 to 3.51, P < 0.001) were also associated with myocardial injury. Associations remained significant after adjusting for intraoperative hypotension, which independently was not associated with myocardial injury. CONCLUSIONS: In this study, postoperative hypotension was common and was independently associated with myocardial injury.

Preoperative coronary angiography in vascular surgery patients with asymptomatic elevated high-sensitivity troponin T: a case series.

This case series presents 10 patients undergoing vascular surgery with asymptomatic elevated high-sensitivity troponin T concentrations, measured at outpatient clinic before surgery. Patients were included in the RAVE (Rotterdam Antiplatelet therapy in Vascular patiEnts) pilot study. All included patients underwent coronary angiography before surgery to identify significant obstructive coronary artery disease. We identified five out of 10 patients with high-grade stenosis and high-risk angiographic features of left main and/or proximal left anterior descending coronary artery disease. The study was terminated prematurely before any subject reached the study endpoint of 1 yr follow-up. This case series provides more insight into the meaning of preoperative troponin elevation and coronary angiographic features in vascular surgery patients. TRIAL REGISTRY NUMBER: NL5803.

Type D Personality and Health-Related Quality of Life in Vascular Surgery Patients.

BACKGROUND: This study evaluated the association of type D personality and health-related quality of life (HRQoL) and assessed the stability of type D personality in vascular surgery patients during the year after surgery. METHOD: In a prospective cohort study between 2008 and 2014, 294 patients were assessed with validated questionnaires preoperatively and at 1, 6, and 12 months after surgery. Associations between type D personality, depression, and HRQoL were analyzed by generalized estimating equation models. Type D personality was analyzed in its standard dichotomous form as well as continuous (z) scores of its two components, negative affectivity (NA) and social inhibition (SI), and their interaction term. RESULTS: Prevalence of type D personality varied between 18% and 25%. However, only 9% of the complete responders were classified as type D personality at all four assessments, whereas one third changed between type D classifications. Continuous scores showed greater stability over time. Dichotomized type D personality measured over time was significantly associated with impaired HRQoL, but this was not the case if measured once at baseline, like in general use. The continuous NA score and depression were also significantly associated with impaired HRQoL over time. CONCLUSION: Type D personality was not a stable trait over time. Preoperative assessment of type D personality did not predict improvement in HRQoL after vascular surgery. However, the study revealed associations between the NA component of type D personality, depression, and lower HRQoL. This indicates that measures of overall negative affect should be taken into account when assessing HRQoL patient-reported outcomes in vascular surgery patients.

What we can learn from Big Data about factors influencing perioperative outcome.

PURPOSE OF REVIEW: This narrative review will discuss what value Big Data has to offer anesthesiology and aims to highlight recently published articles of large databases exploring factors influencing perioperative outcome. Additionally, the future perspectives of Big Data and its major pitfalls will be discussed. RECENT FINDINGS: The potential of Big Data has given an incentive to create nationwide and anesthesia-initiated registries like the MPOG and NACOR. These large databases have contributed in elucidating some of the rare perioperative complications, such as declined cognition after exposure to general anesthesia and epidural hematomas in parturients. Additionally, they are useful in finding patterns such as similar outcome in subtypes of beta-blockers and lower incidence of pneumonia in preoperative influenza vaccinations in the elderly. SUMMARY: Big Data is becoming increasingly popular with the collaborative collection of registries offering anesthesia a way to explore rare perioperative complications and outcome to encourage further hypotheses testing. Although Big Data has its flaws in security, lack of expertise and methodological concerns, the future potential of analytics combined with genomics, machine learning and real-time decision support looks promising.

One-Year Follow-Up After Hybrid Thoracoabdominal Aortic Repair.

BACKGROUND: Compared to open thoracoabdominal aortic aneurysm (TAAA) repair, hybrid repair is thought to be less invasive with better perioperative outcomes. Due to the extent of the operation and long recovery period, studying perioperative results may not be sufficient for evaluation of the true treatment effect. The aim of this study is to evaluate 1-year mortality and morbidity in patients with TAAA undergoing hybrid repair. METHODS: In a retrospective cohort study, all medical records of patients undergoing hybrid repair for TAAA at the Erasmus University Medical Center between January 2007 and January 2015 were studied. Primary outcome measures were 30-day and 1-year mortality. Secondary outcome measures included major in-hospital postoperative complications. RESULTS: A total of 15 patients were included. All-cause mortality was 33% (5 of the 15) at 30 days and 60% (9 of the 15) at 1 year. Aneurysm-related mortality was 33% (5 of the 15) and 53% (8 of the 15) at 30-day and 1-year follow-up, respectively, with colon ischemia being the most common cause of death. Major complication rate was high: myocardial infarction in 2 (13%) cases, acute kidney failure in 5 (33%) cases, bowel ischemia in 3 (20%) cases, and spinal cord ischemia in 1 (7%) case. CONCLUSION: The presumed less invasive nature of hybrid TAAA repair does not seem to result in lower complication rates. The high mortality rate at 30 days continues to rise dramatically thereafter, suggesting that 1-year mortality is a more useful clinical parameter to use in preoperative decision-making for this kind of repair.

Coronary revascularization induces a shift from cardiac toward noncardiac mortality without improving survival in vascular surgery patients.

OBJECTIVE: Although evidence has shown that ischemic heart disease (IHD) in vascular surgery patients has a negative impact on the prognosis after surgery, it is unclear whether directed treatment of IHD may influence cause-specific and overall mortality. The objective of this study was to determine the prognostic implication of coronary revascularization (CR) on overall and cause-specific mortality in vascular surgery patients. METHODS: Patients undergoing surgery for abdominal aortic aneurysm, carotid artery stenosis, or peripheral artery disease in a university hospital in The Netherlands between January 2003 and December 2011 were retrospectively included. Survival estimates were obtained by Kaplan-Meier and Cox regression analysis. RESULTS: A total of 1104 patients were included. Adjusted survival analyses showed that IHD significantly increased the risk of overall mortality (hazard ratio [HR], 1.50; 95% confidence interval, 1.21-1.87) and cardiovascular death (HR, 1.93; 95% confidence interval, 1.35-2.76). Compared with those without CR, patients previously undergoing CR had similar overall mortality (HR, 1.38 vs 1.62; P = .274) and cardiovascular mortality (HR, 1.83 vs 2.02; P = .656). Nonrevascularized IHD patients were more likely to die of IHD (6.9% vs 35.7%), whereas revascularized IHD patients more frequently died of cardiovascular causes unrelated to IHD (39.1% vs 64.3%; P = .018). CONCLUSIONS: This study confirms the significance of IHD for postoperative survival of vascular surgery patients. CR was associated with lower IHD-related death rates. However, it failed to provide an overall survival benefit because of an increased rate of cardiovascular mortality unrelated to IHD. Intensification of secondary prevention regimens may be required to prevent this shift toward non-IHD-related death and thereby improve life expectancy.

The impact of perioperative red blood cell transfusions on postoperative outcomes in vascular surgery patients.

BACKGROUND: Red blood cell (RBC) transfusions are common in vascular surgery and aim to reduce tissue ischemia. However, the evidence that transfusions are beneficial is contradictory. This study evaluates the impact of perioperative transfusion (transfusion within 3 days of surgery) on 30-day postoperative outcomes in elective vascular surgery patients. METHODS: This observational cohort included 1,041 vascular surgery patients between 2002 and 2011 in a tertiary referral center for whom hemoglobin levels were retrospectively available. Patients who received transfusions after 3 days postoperatively were excluded. A propensity score was developed for the likelihood of receiving perioperative transfusion. The study end points were 30-day cardiovascular (CV) events (myocardial infarction, heart failure, arrhythmias, stroke, asymptomatic troponin-T release, and CV death) and all-cause mortality. Multivariable logistic regression analyses, adjusting for relevant confounders and transfusion propensity, were used to determine the associations between perioperative transfusion and the study end points. RESULTS: The final study sample comprised 992 patients; 265 (27%) patients received perioperative transfusions. During the 30-day follow-up, a total of 190 (19%) patients suffered from a 30-day postoperative CV event, of which 116 (44%) occurred in patients who received perioperative RBC transfusions compared with 74 (10%) patients without transfusions (P < 0.01). The end point all-cause mortality was reached in 36 (4%) patients-26 (10%) patients with perioperative RBC transfusion compared with 10 (1%) patients without transfusion (P < 0.01). Perioperative transfusion was associated with an independently increased risk of 30-day CV events (odds ratio 5.0; 95% confidence interval 3.1-8.2) and all-cause mortality (odds ratio 4.4; 95% confidence interval 1.6-12.1). CONCLUSION: Perioperative transfusion is associated with a strongly increased risk of both 30-day CV events and mortality in elective vascular surgery patients.

Impact of haemoglobin concentration on cardiovascular outcome after vascular surgery: a retrospective observational cohort study.

BACKGROUND: Although low preoperative haemoglobin (Hb) concentration is a well known risk factor for adverse outcome, little is known about decreases in Hb and postoperative Hb concentrations. OBJECTIVES: The aim of this study was to evaluate the prognostic impact of both pre- and postoperative Hb concentrations (divided into low, intermediate and high tertiles) as well as Hb decrease, defined as preoperative minus postoperative Hb (g dl(-1)), on postoperative cardiovascular events in vascular surgery patients. DESIGN: A retrospective observational cohort study. SETTING: Erasmus University Medical Centre, Rotterdam, the Netherlands, from 1 January 2002 to 31 December 2011. PATIENTS: One thousand four hundred and eighty-four patients underwent elective open or endovascular abdominal aortic repair (aneurysm or stenosis), lower extremity arterial repair or carotid surgery. Patients for whom pre or postoperative Hb concentrations were not available were excluded. MAIN OUTCOME MEASURES: The study endpoint was 30-day postoperative cardiovascular events, including myocardial infarction, heart failure, arrhythmias, stroke, asymptomatic troponin-T release and cardiovascular death. RESULTS: In 1041 patients, both pre and postoperative Hb concentrations were available. Thirty-day cardiovascular events occurred in 221 (21%) patients. Multivariable logistic regression analyses, adjusting for age, sex, Revised Cardiac Risk Index (high-risk surgery, coronary heart disease, heart failure, cerebrovascular disease, diabetes mellitus, renal insufficiency), hypertension and hypercholesterolaemia, demonstrated that low preoperative Hb (8.7 to 12.9 g dl(-1)) was associated with 30-day events [odds ratio (OR) 1.7; 95% confidence interval (CI) 1.1 to 2.5]. Intermediate (10.6 to 12.1 g dl(-1)) and low (7.4 to 10.5 g dl(-1)) postoperative Hb and Hb decrease were also associated with an independently increased risk of 30-day events (intermediate Hb: OR 1.7; 95% CI 1.1 to 2.7; low Hb: OR 3.1; 95% CI 2.0 to 4.8; and Hb decrease: OR 1.2; 95% CI 1.1 to 1.3, respectively). Sensitivity analyses excluding patients with transfusions (n=314) demonstrated that only postoperative Hb concentrations remained associated with a high risk of 30-day cardiovascular events (intermediate Hb: OR 1.8; 95% CI 1.0 to 3.3 and low Hb: OR 2.0; 95% CI 1.0 to 4.0). CONCLUSION: Pre and postoperative Hb concentrations and Hb decrease are all related to 30-day cardiovascular events in elective vascular surgery patients. Postoperative Hb concentrations are the strongest predictor of 30-day cardiovascular events.

Effect of major and minor surgery on plasma levels of arginine, citrulline, nitric oxide metabolites, and ornithine in humans.

OBJECTIVE: To determine the effect of surgical invasiveness on plasma levels of arginine, citrulline, ornithine, and nitric oxide (NO) in humans. BACKGROUND: Surgical trauma may have a profound effect on the metabolism of NO. However, human studies reported both increased and decreased NO levels after hemorrhagic shock. Arginine, citrulline, and ornithine are key amino acids involved in NO metabolism, but studies evaluating these amino acids together with NO and during 2 types of surgery are lacking. This study tests the hypothesis that major surgery has a more profound effect on plasma levels of arginine, citrulline, NO, and ornithine than minor surgery. METHODS: Fifteen patients undergoing minor surgery (vulvectomy) and 13 patients undergoing major surgery (laparotomy) were prospectively followed up for 4 days. Plasma was collected for evaluation of levels of arginine, citrulline, NO, and ornithine. RESULTS: Throughout the experiment, arginine levels did not significantly differ between experimental groups. Perioperative plasma citrulline levels were significantly lower in the laparotomy group than in the vulvectomy group, whereas both groups showed a decrease in citrulline levels at the end of the operation and 24 hours postoperatively. Roughly the same pattern was seen for plasma NO and ornithine levels. However, ornithine levels in the laparotomy group showed a more drastic decrease at the end of the operation and 24 hours postoperatively than citrulline and NO levels. CONCLUSIONS: The level of surgical invasiveness has the most profound effect on plasma levels of ornithine. In addition, heavier surgical trauma is paired with lower postoperative levels of citrulline and NO metabolites than lighter surgery. It is suggested that surgical trauma stimulates the laparotomy group to consume significantly more ornithine, possibly for use in wound healing.

Risk modification for postoperative pulmonary embolism: timing of postoperative prophylaxis.

INTRODUCTION: Risk factors for postoperative pulmonary embolism can often not be modified and are patient related. The purpose of this case control study was to identify possible modifiable risk factors for postoperative pulmonary embolism. MATERIALS AND METHODS: We undertook a case control study among 210,269 patients who underwent noncardiac surgery from 2000 to 2009 at the Erasmus Medical Center. Case subjects were all 199 (0.09%) patients who experienced a pulmonary embolism within 30 days after surgery. From the remaining patients, 1 control was selected for each case and was stratified according to calendar year. For cases and controls, information was obtained regarding risk factors and the type and dose of thromboprophylaxis as well as the time of postoperative initiation. RESULTS: Overweight, surgery for malignancy, a history of cerebrovascular disease and a history of thromboemblic diseases, intraoperative blood transfusions and delayed use of thromboprophylaxis were more common in cases than in controls. After correction delayed use of thromboprophylaxis was associated with a 4 fold increased risk (OR 4.1; 95% CI: 2.1 - 7.7) for postoperative pulmonary embolism. CONCLUSION: Delayed timing of postoperative thromboprophylaxis is an important modifiable risk factor for postoperative pulmonary embolism after noncardiac surgery. This study emphasises the importance of on time administration of thromboprophylaxis.

Epidural analgesia is associated with improved health outcomes of surgical patients with chronic obstructive pulmonary disease.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) have increased postoperative morbidity and mortality. Epidural analgesia (EDA) improves postoperative outcome but may worsen postoperative lung function. It is unknown whether patients with COPD benefit from EDA. The objective of this study was to determine whether patients with COPD undergoing major abdominal surgery benefit from EDA in addition to general anesthesia. METHODS: This cohort study included 541 consecutive patients with COPD who underwent major abdominal surgery between 1995 and 2007 at a university medical center. Propensity scores estimating the probability of receiving EDA were used in multivariate correction. The primary outcome was postoperative pneumonia and 30-day mortality. RESULTS: There were 324 patients (60%) who received EDA in addition to general anesthesia. The incidence of postoperative pneumonia (16% vs. 11%; P = 0.08) and 30-day mortality (9% vs. 5%; P = 0.03) was lower in patients who received EDA. After correction EDA was associated with improved outcome for postoperative pneumonia (OR 0.5; 95% CI: 0.3-0.9; P = 0.03). The strongest preventive effect was seen in patients with the most severe type of COPD. CONCLUSION: This study provides evidence that in patients with COPD who are scheduled for major abdominal surgery, epidural analgesia decreases postoperative pulmonary complications.