Elective Abdominal Aortic Surgery Research Articles

Reliability of Bioreactance and Pulse-Power Analysis in Measuring Cardiac Index During Open Abdominal Aortic Surgery

To investigate the accuracy, precision, and trending ability of noninvasive bioreactance-based Starling SV and the mini invasive pulse-power device LiDCOrapid as compared to thermodilution cardiac output (TDCO) as measured by pulmonary artery catheter when assessing cardiac index (CIx) in the setting of elective open abdominal aortic (AA) surgery. A prospective method-comparison study. Oulu University Hospital, Finland. Forty patients undergoing elective open abdominal aortic surgery. Intraoperative CI measurements were obtained simultaneously with TDCO and the study monitors, resulting in 627 measurement pairs with Starling SV and 497 with LiDCOrapid. The Bland-Altman method was used to investigate the agreement among the devices, and four-quadrant plots with error grids were used to assess trending ability. The agreement between TDCO and Starling SV was associated with a bias of 0.18 L/min/m2 (95% confidence interval [CI] = 0.13 to 0.23), wide limits of agreement (LOA = -1.12 to 1.47 L/min/m2), and a percentage error (PE) of 63.7 (95% CI = 52.4-71.0). The agreement between TDCO and LiDCOrapid was associated with a bias of -0.15 L/min/m2 (95% CI = -0.21 to -0.09), wide LOA (-1.56 to 1.37), and a PE of 68.7 (95% CI = 54.9-79.6). The trending ability of neither device was sufficient. The CI measurements achieved with Starling SV and LiDCOrapid were not interchangeable with TDCO, and the ability to track changes in CI was poor. These results do not support the use of either study device in monitoring CI during open AA surgery.

The role of Tranexamic acid in the Reduction of Bleeding in Abdominal Aortic Aneurysm Surgery

Objective: To determine the effects of Tranexamic acid on intraoperative blood loss. Study Design: Quasi-experimental study. Place and Duration of Study: Combined Military Hospital, Rawalpindi Pakistan, from Jun to Oct 2021. Methodology: A total of 96 patients from both genders undergoing elective open abdominal aortic aneurysm surgery under general anaesthesia enrolled in the study after random distribution to Drug and Control Groups. The primary determinant was intraoperative blood loss. Additionally, determining variables were intraoperative and postoperative blood transfusions, thromboembolic episodes, and postoperative mortality rate. Results: A total of 96 patients enrolled in the study, out of which 90(93%) were males, whereas 6(7%) were females, with a mean age of 65.37±7.01 (55–75 years). Of 96 participants, 52(54%) patients were from ASA Class II and 44(46%) were from ASA Class III. There was no significant correlation between surgical time (p-value 0.45), clamping time (p-value 0.34), and intraoperative and postoperative transfusions (p-value 0.56 and 0.28, respectively). However, a statistically significant reduction in intraoperative and postoperative blood loss was recorded (p-value <0.001). Conclusion: Tranexamic acid significantly impacts the reduction of intraoperative and postoperative bleeding in elective open abdominal aortic aneurysm surgeries under general anaesthesia.

Enhancing predictive accuracy of the cardiac risk score in open abdominal aortic surgery: the role of left ventricular wall motion abnormalities.

Open abdominal aortic surgery carries many potential complications, with cardiac adverse events being the most significant concern. The Vascular Study Group Cardiac Risk Index (VSG-CRI) is a commonly used tool for predicting severe cardiac complications and guiding clinical decision-making. However, despite the potential prognostic significance of left ventricular wall motion abnormalities (LVWMAs) and reduced LV ejection fraction (LVEF) for adverse outcomes, the VSG-CRI model has not accounted for them. Hence, the main objective of this study was to analyze the added value of LV wall motion on the discriminatory power of the modified VSG-CRI in predicting major postoperative cardiac complications. A prospective study was conducted involving 271 patients who underwent elective abdominal aortic surgery between 2019 and 2021. VSG-CRI scores were calculated, and preoperative transthoracic echocardiography was conducted for all patients. Subsequently, a modified version of the VSG-CRI, accounting for reduced LVEF and LVWMAs, was developed and incorporated into the dataset. The postoperative incidence of the composite endpoint of major adverse cardiac events (MACEs), including myocardial infarction, clinically relevant arrhythmias treated with medicaments or by cardioversion, or congestive heart failure, was assessed at discharge from the index hospitalization, with adjudicators blinded to events. The predictive accuracy of both the original and modified VSG-CRI was assessed using C-Statistics. In total, 61 patients (22.5%) experienced MACEs. Among these patients, a significantly higher proportion had preoperative LVWMAs compared to those without (62.3% vs. 32.9%, p < 0.001). Multivariable regression analysis revealed the VSG-CRI [odds ratio (OR) 1.46, 95% confidence interval (CI) 1.21-1.77; p < 0.001] and LVWMA (OR 2.76; 95% CI 1.46-5.23; p = 0.002) as independent predictors of MACEs. Additionally, the modified VSG-CRI model demonstrated superior predictability compared to the baseline VSG-CRI model, suggesting an improved predictive performance for anticipating MACEs following abdominal aortic surgery [area under the curve (AUC) 0.74; 95% CI 0.68-0.81 vs. AUC 0.70; 95% CI 0.63-0.77; respectively]. The findings of this study suggest that incorporating preoperative echocardiography can enhance the predictive accuracy of the VSG-CRI for predicting MACEs after open abdominal aortic surgery. Before its implementation in clinical settings, external validation is necessary to confirm the generalizability of this newly developed predictive model across different populations.

Postoperative Myocardial Injury and Inflammatory Biomarkers in Patients Undergoing Vascular Surgery: A Subanalysis of the Platelet Reactivity and Postoperative Myocardial Injury after Major Vascular Surgery (PROMISE) Study

BackgroundPostoperative myocardial injury (PMI) is associated with morbidity and mortality, but the aetiology remains unclear. We studied whether PMI is associated with perioperative systemic inflammation. ObjectiveTo examine the relationship between inflammatory biomarkers (Interleukin 6[IL-6], C-reactive protein [CRP]) and PMI, detected by elevated cardiac troponin (cTn), in patients undergoing elective open abdominal aortic surgery. MethodsThis prospective, single-centre, observational, cohort study included 54 patients undergoing elective open abdominal aortic surgery between March 2018 and April 2021. Patients were routinely treated with aspirin. IL-6 and CRP were measured pre-operatively, directly after surgery, 24h and 48h post-operative. The primary outcome was cTn release assessed by a fifth generation high-sensitive cTn assay. Multivariable generalized linear regression models were used to evaluate the association between inflammatory biomarkers and cTn concentrations. ResultsFifteen patients (27.8%) developed PMI. IL-6 directly and 24h post-operatively was associated with elevated cTn concentrations (1.28 [1.07-1.54], p=0.009)) and 1.75 [1.18-2.59], p=0.006, respectively). Also, CRP directly and 24h post-operatively was associated with elevated cTn concentrations (1.25 [1.06-1.47], p=0.009)) and 1.61 [1.1-2.33], p=0.013, respectively). No association was found between IL-6 or CRP and cTn concentrations when measured at 48h post-surgery. ConclusionBiomarkers of inflammation are associated with elevated post-operative cTn concentrations in the early postoperative period in patients undergoing elective open abdominal aortic surgery.

Prognostic value of extended cardiac risk assessment before elective open abdominal aortic surgery.

Major vascular surgery is associated with ahigh perioperative risk and significant mortality. Despite advances in risk stratification, monitoring, and management of perioperative complications, cardiac complications are still common. Stress echocardiography is well established in coronary artery disease diagnostics; however, its prognostic value before high-risk aortic surgery is unknown. This prospective, single-center study compared the outcome of patients undergoing extended cardiac risk assessment before open abdominal aortic surgery with the outcome of patients who had received standard preoperative assessment. The study included patients undergoing elective open abdominal aortic surgery. Patients who underwent standard preoperative assessment before the start of adedicated protocol were compared with patients who had extended cardiac risk assessment, including dobutamine stress echocardiography, as part of astepwise interdisciplinary cardiovascular team approach. The combined primary endpoint was cardiovascular death, myocardial infarction, emergency coronary revascularization, and life-threatening arrhythmia within 30days. The secondary endpoint was acute renal failure and severe bleeding. In total, 77patients (mean age 68.1 ± 8.1years, 70% male) were included: 39underwent standard and 38underwent cardiac risk assessment. The combined primary endpoint was reached significantly more often in patients before than after implementation of the extended cardiac stratification procedure (15% vs. 0%, p = 0.025). The combined secondary endpoint did not differ between the groups. Patients with extended cardiac risk assessment undergoing elective open abdominal aortic surgery had better 30-day outcomes than did those who had standard preoperative assessment.

Impact of General Anaesthesia Versus Combined Epidural and General Anesthesia on Postoperative Complications and Mortality in Elective Abdominal Aortic Aneurysm Surgeries

Objective: To determine the impact of general anaesthesia versus combined epidural and general anaesthesia on postoperative complications in elective abdominal aortic aneurysm surgeries.&#x0D; Study Design: Quasi-experimental study.&#x0D; Place and Duration of Study: Combined Military Hospital, Rawalpindi Pakistan, from Jun 2018 to Sep 2020.&#x0D; Methodology: A total of 100 patients from both genders undergoing elective open abdominal aortic aneurysm surgery under general anaesthesia enrolled in the study after random distribution to drug and control groups in equal proportions. The primary determinants were postoperative complications. Additionally, it determined the impact on postoperative mortality rate. &#x0D; Results: Of 100 participants, 54% of patients were from ASA status II, and 46% were from ASA status III. Among postoperative complications, bowel ischemia was recorded in 16% and 2% among Group-A and Group-B, respectively (pvalue 0.01). Postoperative dialysis was required in 18% of patients in Group-A, whereas among Group-B, only 4%went through it (p-value 0.02). Pulmonary complications variation was not statistically different between the two groups, with 54% and 46% (p-value 0.42) frequencies in Group-A and Group-B, respectively. However, surgical reintervention within 30 days was notable, 36% in Group-A and 14% in Group-B (p-value 0.01).&#x0D; Conclusion: Combined general and epidural anaesthesia, when compared with general anaesthesia alone, significantly impacts the reduction of postoperative complications after elective open abdominal aortic aneurysm surgeries without increasing morbidity and mortality.

25, 50 and 75 years ago

25, 50 and 75 years ago

Myocardial and renal protective effects of Dexmedetomidine vs Magnesium sulphate in patients undergoing elective open abdominal aortic surgery

Myocardial and renal protective effects of Dexmedetomidine vs Magnesium sulphate in patients undergoing elective open abdominal aortic surgery

Salivary cortisol as a biomarker of stress in surgical patients.

Surgical stress and pain result in activation of hypothalamus-pituitary-adrenal axis. The aim of this study was to establish the effects of postoperative pain and various modalities of analgesic administration on salivary and serum cortisol levels, as well as to establish the validity of salivary cortisol as a stress indicator in surgical patients. A randomized controlled trial involved 60 patients scheduled for elective abdominal aortic aneurysm surgery. Patients were randomly divided into two groups depending on the model of postoperative analgesia. The first group (MI - morphine intermittently) included patients given morphine doses 0.1 mg/kg/6h s.c. intermittently. The second group (MPCA - morphine patient-controlled analgesia) included patients who received morphine via the PCA system - intravenous administration of morphine adjusted to a dose of 1 mg per shot and a lockout interval of 6 minutes.

Procena kardijalnog rizika u elektivnoj otvorenoj reparaciji aneurizme abdominalne aorte

When indicated, patients with abdominal aortic aneurysm are referred for elective abdominal aortic surgery. Abdominal aortic aneurysm open repair is associated with a high risk for the development of cardiovascular morbidity and mortality. Cardiac risk assessment in abdominal aortic surgery includes evaluation of the likelihood of adverse cardiac events during surgery and/or in the postoperative period. Overall cardiac risk is assessed individually for the patient, taking into account the patient's general condition, cardiac function, patient functional capacity, comorbidity status, and vascular surgery risk. Cardiac morbidity and mortality are several times higher in emergency procedures than in elective abdominal aortic procedures, as well as in surgical procedures compared to endovascular procedures, especially in cases with suprarenal clamping of the aorta. Patients with ischemic heart disease and heart failure are at high risk for adverse cardiac events. Pathophysiologic mechanisms activated intraoperatively by aortic clamping and unclamping, hemodynamic fluctuations, blood loss, coagulopathy, and ischemia-reperfusion injury influence the potential development of perioperative infarction, heart failure, and cardiac arrest in high-risk patients. Assessment of perioperative cardiac function and cardiac risk using leading recommendations and scoring systems before surgery may change the approach to management of high-risk patients with multiple comorbidities and significantly reduce the incidence of perioperative morbidity and mortality.

Patient blood management using dedicated personnel in the operating room-you get what you pay for.

A patient blood management (PBM) strategy can be applied to the process of intraoperative cell salvage for re-infusion during surgery. Stoneham et al. describe an effective PBM strategy applied to abdominal aortic aneurysm repair and emphasise the importance of a qualified and experienced intraoperative cell salvage practitioner to improve the safety and effectiveness of the approach. Commentary on: Stoneham et al. Intraoperative cell salvage using swab wash and serial thromboelastography in elective abdominal aortic aneurysm surgery involving massive blood loss. Br J Haematol 2023;200:652-659.

Intraoperative cell salvage using swab wash and serial thromboelastography in elective abdominal aortic aneurysm surgery involving massive blood loss.

The loss of 50% blood volume is one accepted definition of massive haemorrhage, which ordinarily would trigger the massive transfusion protocol, involving the administration of high ratios of fresh frozen plasma and platelets to allogeneic red cells. We investigated 53 patients who experienced >50% blood loss during open elective abdominal aortic aneurysm surgery to assess allogeneic blood component usage and coagulopathy. Specialist patient blood management practitioners used a tailored cell salvage technique including swab wash to maximise blood return. We assessed the proportion of patients who did not require allogeneic blood components and develop evidence of coagulopathy by thromboelastography (TEG) parameters. Blood loss was 50%-174% (mean [SD] 68% [27%]) of blood volume. The mean (SD) intraoperative decrease in haemoglobin concentration, assessed by arterial blood gas analysis, was 5(13)g/l. No patient received allogeneic red cells intraoperatively. Four of the 53 (8%) patients received blood components in the first 24 h postoperatively at the anaesthetists' discretion. No patient had intraoperative TEG changes indicative of fibrinolysis or coagulopathy. The 30-day mortality was 2% (one of 53). Reduction of allogeneic transfusion is one aim of patient blood management techniques. We have demonstrated virtual avoidance of allogeneic blood product transfusion despite massive blood loss. These data show possible alternatives to the current massive transfusion protocols to the management of elective vascular surgical patients.

Postoperative myocardial injury and platelet reactivity in patients undergoing vascular surgery: The platelet reactivity and postoperative myocardial injury after major vascular surgery (PROMISE) study

BackgroundPostoperative myocardial injury (PMI) after major vascular surgery, detected by elevated cardiac troponin (cTn), has been associated with morbidity and mortality. It is unclear whether the pathophysiology of PMI is determined by increased platelet activity. ObjectiveTo examine the relationship between platelet activation (P-selectin expression) and PMI in patients undergoing elective open abdominal aortic surgery. MethodsThis prospective, single-centre, observational, cohort study included 33 patients undergoing elective open abdominal aortic surgery between March 2018 and April 2021. Patients were routinely treated with aspirin. Unstimulated platelet activation was measured by platelet bound P-selectin expression (range 0–100 %). Explorative coagulation measurements were: stimulated platelet aggregation measured with the VerifyNow® assay (aspirin cartridge), with the Multiplate® analyzer (ASPI, ADP and TRAP) and stimulated coagulation status evaluated by the TEG® Hemostasis Analyzer System (global hemostasis cartridge). The primary outcome was cTn release assessed by the fifth generation high-sensitive cTn assay. Multivariable generalized linear mixed models were used to evaluate the association between platelet function and cTn concentrations over time. ResultsTen patients (30.3 %) developed PMI. Increased P-selectin expression directly after surgery was associated with the cTn concentrations over 48 h (β = 1.39 (1.1–1.75), P = 0.0064). No association was found between P-selectin measured later after surgery (at 24 h or 48 h) and cTn concentrations. Furthermore, there was no association between the explorative coagulation parameters and cTn release. ConclusionPlatelet reactivity, assessed by P-selectin expression measured directly after surgery is associated with PMI, assessed by elevated cTn concentrations in the early postoperative period in patients undergoing elective open abdominal aortic surgery.

Continuous Transversus Abdominis Plane Infusion via Surgically Inserted Catheter for Postoperative Analgesia After Abdominal Aortic Surgery by Retroperitoneal Approach: TAPCACAO Study

The purpose of our study was to evaluate the analgesic properties of continuous transversus abdominis plane (TAP) infusion with ropivacaine compared to placebo for postoperative analgesia in elective surgery of the abdominal aorta by retroperitoneal exposure. We conducted a prospective, single-center, randomized, double-blind study comparing a group of patients with a TAP catheter undoing ropivacaine infusion with a placebo group. Patients received a left retroperitoneal pararectal exposure for abdominal aortic surgery. A continuous infusion catheter was placed under visual control by the surgeon before closure and removed after 48hr. All patients had postoperative patient-controlled analgesia with morphine. The primary endpoint was morphine consumption during the first 24hr. The analysis included 25 patients in the placebo group and 24 in the ropivacaine group. The average morphine consumption during the first 24hr was significantly different, with 31±16mg in the ropivacaine group and 41±17mg in the placebo group (P=0.019). At 48hr, morphine consumption was still lower in the ropivacaine group (42±26mg) than in the placebo group (64±25mg) (P=0.003). The opioid narcotic-related side effects of opioid infusion (postoperative nausea and vomiting, constipation) and length of hospital stay were similar in both populations. Our study showed that continuous TAP block with ropivacaine via surgically inserted catheter significantly decreased morphine consumption at 24 and 48hr after elective abdominal aortic surgery by retroperitoneal exposure.

Extended intensive care correlates with worsening of surgical outcome after elective abdominal aortic reconstruction

The aim of this study was to evaluate the impact of extended postoperative intensive care on short- and long-term patient outcome after elective abdominal aortic surgery and to assess the risk factors for patient survival after extended intensive care unit (ICU) treatment. The data of 231 patients that underwent open or endovascular abdominal aortic surgery were retrospectively analysed with regard to extended postoperative intensive care, defined as ICU treatment for more than 24 consecutive hours. Pre- and intraoperative factors were evaluated. The endpoints of the study were postoperative complications, mortality, and long-term follow-up. Univariate and multivariate Cox proportional regression analyses were performed to identify risk factors of worse overall survival. Extended postoperative intensive care was needed in 84 patients (63 after open and 21 after endovascular surgery). The period of ICU treatment was similar in both groups. Only the wound complications (31.8% vs. 9.5%, P=0.0498; OR 4.42 [0.94-20.84]) and the rate of acute kidney injury (82.5% vs. 57.1%, P=0.0352; OR 3.55 [1.20-0.46]) were more frequent after open surgery, whereas brief reactive psychosis (38.1% vs. 14.3%, P=0.0281; OR 0.27 [0.09-0.84]) was more frequent after endovascular surgery. ICU stay of ≥8 days correlated with significantly lower survival rates compared to a shorter ICU stay (P=0.0034), independent of open or endovascular techniques. Other multivariate risk factors for worse survival were the absence of preoperative aspirin medication, a Body Mass Index (BMI) of <25, chronic renal insufficiency, and coronary artery disease. Endovascular therapy was a positive predictive factor of short ICU stay of ≤3 days. The outcome after extended intensive care following elective aortic surgery is strongly dependent on the length of ICU stay.

Volume–Outcome Relationships in Elective Abdominal Aortic Aneurysm Surgery: Analysis of the UK Hospital Episodes Statistics Database for the Getting It Right First Time (GIRFT) Programme

To investigate whether a volume–outcome relationship exists for elective abdominal aortic aneurysm (AAA) surgery conducted within the National Health Service (NHS) in England. This was an analysis of administrative data. Data were extracted from the Hospital Episodes Statistics database for England from April 2011 to March 2019 for all adult admissions for elective infrarenal AAA surgery. Data were extracted for the NHS trust and surgeon undertaking the procedure, the surgical technique used (open or endovascular), the financial year of admission, length of hospital and critical care stay during the procedure and subsequent emergency re-admissions (primary outcome) and deaths within 30 days. Multilevel modelling was used to adjust for hierarchy and confounding. A dataset of 31 829 procedures (8867 open, 22 962 endovascular) was extracted. For open surgery, lower trust annual volume was associated with higher 30 day emergency re-admission rates and higher 30 day mortality. For open surgery, lower surgeon annual volume was associated with higher 30 day mortality and length of hospital stay greater than the median. For endovascular surgery, lower surgeon annual volume was associated with not having an overnight stay in critical care. None of the other volume–outcome relationships investigated was significant. For elective infrarenal AAA surgery in the UK NHS, there was strong evidence of a volume–outcome relationship for open surgery. However, evidence for a volume–outcome relationship is dependent on the specific procedure undertaken and the outcome of interest.

Editor's Choice – Volume–Outcome Relationships in Elective Abdominal Aortic Aneurysm Surgery: Analysis of the UK Hospital Episodes Statistics Database for the Getting It Right First Time (GIRFT) Programme

To investigate whether a volume-outcome relationship exists for elective abdominal aortic aneurysm (AAA) surgery conducted within the National Health Service (NHS) in England. This was an analysis of administrative data. Data were extracted from the Hospital Episodes Statistics database for England from April 2011 to March 2019 for all adult admissions for elective infrarenal AAA surgery. Data were extracted for the NHS trust and surgeon undertaking the procedure, the surgical technique used (open or endovascular), the financial year of admission, length of hospital and critical care stay during the procedure and subsequent emergency re-admissions (primary outcome) and deaths within 30 days. Multilevel modelling was used to adjust for hierarchy and confounding. A dataset of 31829 procedures (8867 open, 22962 endovascular) was extracted. For open surgery, lower trust annual volume was associated with higher 30 day emergency re-admission rates and higher 30 day mortality. For open surgery, lower surgeon annual volume was associated with higher 30 day mortality and length of hospital stay greater than the median. For endovascular surgery, lower surgeon annual volume was associated with not having an overnight stay in critical care. None of the other volume-outcome relationships investigated was significant. For elective infrarenal AAA surgery in the UK NHS, there was strong evidence of a volume-outcome relationship for open surgery. However, evidence for a volume-outcome relationship is dependent on the specific procedure undertaken and the outcome of interest.

One-year patient survival correlates with surgeon volume after elective open abdominal aortic surgery

ObjectiveVolume-outcome relationships in surgery have been well established. Studies have shown that high-volume surgeons provide improved outcomes in performing open abdominal aneurysm repairs. The hypothesis of this study was that high-volume surgeons provide superior short-term and midterm outcomes of elective open aortic operations compared with low-volume surgeons. MethodsWe evaluated patients undergoing elective open abdominal aortic aneurysm repair, aortofemoral bypass, and aortomesenteric bypass by board-certified vascular surgeons using the New York Statewide Planning and Research Cooperative System database from 2002 to 2014. The Contal and O'Quigley technique was used to estimate a cut point objectively and provided an estimate of significance. A division using average yearly volumes (averaged during 3 years) of seven or more cases and fewer than seven cases per year returned the highest Q statistic, and this grouping was used to classify high-volume and low-volume provider groups. Rates of complications during index hospitalization, length of stay, 30-day survival, 90-day survival, 1-year survival, and cause of death were analyzed using mixed effect models. ResultsIn 118 hospitals during the 13-year period, 266 board-certified vascular surgeons performed 244 aortomesenteric bypasses, 4202 aortofemoral bypasses, and 6126 abdominal aortic aneurysm repairs. High-volume surgeons' rates of complications during index hospitalization, 30-day survival, 90-day survival, and 1-year survival were superior to those of low-volume surgeons. The Contal and O'Quigley technique returned an estimate of seven operations per year for optimal survival during 1 year. This cutoff is associated with an adjusted 1-year hazard ratio of 0.687 (P = .003), a 2.69% difference in 1-year all-cause survival (P = .003), and a 1.76-day reduction in the mean length of stay at index hospitalization (P < .001). Higher volume surgeons showed a 25.0%, 43.4%, 42.4%, 40.6%, and 45.0% reduction in postoperative rates of acute renal failure (P < .001), hemorrhage (P < .001), pulmonary failure (P < .001), sepsis (P < .001), and venous thromboembolism (P < .001), respectively. Abdominal abscess, acute renal failure, hemorrhage, myocardial infarction, and sepsis were associated with increased cardiovascular cause-specific mortality after open aortic operations (P < .001). ConclusionsThese data demonstrate that high-volume surgeons performing elective open aortic operations provide reduced complications and improved short-term and midterm survival compared with low-volume surgeons. Clinical and postoperative variables that are associated with increased cardiovascular cause-specific mortality are also identified. These data provide further evidence that elective open abdominal vascular surgery should be centralized to high-volume surgeons.

Correlation between central venous and mixed venous oxygen saturation in the elective abdominal aortic aneurysm surgery

Background/Aim. The concept of utilizing central venous oxygen saturation (ScvO2) to calculate cardiac index (CI) remains controversial and neither precise nor generally applicable conclusion has been reached yet. We evaluated the relationship between ScvO2 and mixed venous oxygen saturation (SvO2) in elective surgery of the abdominal aorta. The adequacy of their interchangeability was tested by comparing cardiac indices (CI) calculated by two methods in patients that underwent major vascular surgery. The aim of this study was to test the correlation between ScvO2 and SvO2 in different time frames, in patients undergoing elective abdominal aortic aneurysm (AAA) surgery as well as to determine if the use of ScvO2 for calculating CI by the modified Fick equation, could be feasible and accurate surrogate for the values obtained by pulmonary artery catheter (PAC). Methods. This prospective observational study included 125 consecutive patients that underwent elective AAA surgery. The ScvO2 and SvO2 data, as well as CI values, were obtained and compared from samples taken in three different time frames: immediately after induction of general anesthesia (T0), immediately after admission in the intensive care unit (ICU; T1), and 8 h after admission in the ICU (T2). The Fick equation, used for CI estimation from ScvO2 (CI-F), for the purpose of this study, was simplified according to Walley. Results. There was good linear correlation between ScvO2 and SvO2 in all time frames and linear regression study revealed strongest coefficient of determination (R2 = 0.661) in T2 time-frame. There was no correlation between CI-F (i.e. CI calculated from ScvO2 by modified Fick equation) and CI (measured by PAC from SvO2) in any time-frame. Conclusion. The results of our study confirm that ScvO2 is a reliable substitute for SvO2 among patients undergoing elective surgery of the AAA. However, ScvO2 cannot be used as a surrogate to true SvO2 in the calculation of CI.

Current Risk Estimation Models Underestimate Significance of Perioperative Factors in Predicting Mortality After Elective Abdominal Aortic Surgery

Current Risk Estimation Models Underestimate Significance of Perioperative Factors in Predicting Mortality After Elective Abdominal Aortic Surgery