Open Infrarenal Abdominal Aortic Aneurysm Research Articles

The effect of incremental increases in the number of packed red blood cell units transfused on perioperative outcomes in open abdominal aortic aneurysm repair.

Despite abundant evidence in the surgical and critical care literature demonstrating inferior outcomes in transfused patients, liberal use of blood transfusion, particularly after the initial unit, remains common in vascular surgery. We therefore sought to investigate the incremental risk of each additional unit of blood transfused intraoperatively for patients undergoing elective open repair of abdominal aortic aneurysm (AAA) with regards to postoperative mortality and complications. Patients in the Vascular Quality Initiative registry undergoing elective open infrarenal AAA repair from 2003 to 2020 were included. Exclusion criteria were age greater than 90, prior aortic surgery, concomitant iliac aneurysm, and concomitant additional major procedure. Multivariable logistic regression was used to calculate adjusted odds ratios for in-hospital mortality with incremental increases in packed red blood cells (pRBCs) given intraoperatively. Univariate analysis was performed for secondary outcomes including postoperative cardiac, respiratory, renal, and wound complications. Of 4608 patients who underwent elective open AAA repair, 796 patients (16.9%) underwent perioperative transfusion. The overall in-hospital mortality rate was 2.5%. Adjusting for relevant factors, there was an increase in the odds of in-hospital mortality of 24% for each additional unit transfused. Incremental increases in the number of units transfused were associated with significantly higher risk of postoperative myocardial infarction, congestive heart failure, pulmonary complications, renal failure, and wound complications. There appears to be an important increase in the odds of mortality for each additional unit transfused during infrarenal open AAA repair even when controlling for confounders.

A Patient-Centered Textbook Outcome Measure Effectively Discriminates Contemporary Elective Open Abdominal Aortic Aneurysm Repair Quality

IntroductionThere is persistent controversy surrounding the merit of surgical volume benchmarks being used solely as a sufficient proxy for assessing the quality of open abdominal aortic aneurysm (AAA) repair. Importantly, operative volume quotas may fail to reflect a more nuanced and comprehensive depiction of surgical outcomes most relevant to patients. Accordingly, we herein propose a patient-centered “textbook outcome” (TO) for AAA repair that is analogous to other large magnitude extirpative operations performed in other surgical specialties, and test its feasibility to discriminate hospital performance using Society for Vascular Surgery (SVS) volume guidelines. MethodsAll elective open infrarenal AAA repairs (OAR) in the SVS-Vascular Quality Initiative were examined (2009-2022). The primary end-point was a TO, defined as a composite of no in-hospital complication or re-intervention/re-operation, length of stay ≤ 10-days, home discharge and 1-year survival. The discriminatory ability of the TO measure was assessed by comparing centers that did or did not meet the SVS annual OAR volume threshold recommendation (high-volume ≥ 10 OARs/year; low-volume <10 OARs/year). Logistic regression and multivariable models adjusted for patient and procedure-related differences. ResultsA total of 9,657 OARs across 198 centers were analyzed (mean age-69.5±8.4, female-26%, non-white-12%). A TO was identified in 44% (N = 4,293) of the overall cohort. The incidence of individual TO components included: no in-hospital complication (61%), no in-hospital re-intervention/re-operation (92%), LOS ≤ 10-days (78%), home discharge (76%), and 1-year survival (91%). Median annual center volume was 6 [IQR 3, 10] and a majority of centers did not meet the SVS volume suggested threshold (<10 OARs/year: N = 148 [74%]). However, most patients (N = 6,265 of 9,657 [65%]) underwent OAR in high-volume hospitals. When comparing high and low-volume centers, a TO was more likely to occur in high-volume institutions: ≥10 OARs/year, 46% vs. <10 OARs/year, 42%; P=.0006. The association of a protective effect for higher center volume remained after risk adjustment: OR 1.1, 95%CI 1.05-1.26; P=.003. ConclusionsTextbook outcomes for elective OAR reflect a more nuanced and comprehensive patient centered proxy to measure care delivery consistent with other surgical specialties. Surprisingly, a TO was achieved in < 50% of elective AAA cases nationally. Though the likelihood of a TO appears to correlate with SVS center volume recommendations, it more importantly reflects elements which may be prioritized by patients and thus offers insights into further improving real-world AAA care.

Assessment of fitness for open repair in patients with infrarenal abdominal aortic aneurysms

ObjectiveEndovascular aortic repair (EVAR) was originally designed as a treatment modality for patients with abdominal aortic aneurysms (AAAs) deemed unfit for open repair. However, the definition of “unfit for open repair” is largely subjective and heterogenous. The purpose of this study was to compare patients deemed unfit for open repair who underwent EVAR to a matched cohort who underwent open repair for infrarenal AAAs. MethodsThe Vascular Quality Initiative of the Society for Vascular Surgery was queried for patients who underwent EVAR and open infrarenal AAA repair from 2003 to 2022. Patients that underwent EVAR were included if they were deemed unfit for open repair by the operating surgeon. EVAR patients deemed unfit because of a hostile abdomen were excluded. Patients in both the open and EVAR datasets were excluded if their repair was deemed non-elective or if they had prior aortic surgery. EVAR patients were matched to a cohort of open patients. The primary outcome for this study was 1-year mortality. Secondary outcomes included 30-day mortality, major adverse cardiac events, pulmonary complications, non-home discharge, reinterventions, and 5-year survival. ResultsA total of 5310 EVAR patients were identified who were deemed unfit for open repair. Of those, 3028 EVAR patients (57.0%) were able to be matched 1:1 to a cohort of open patients. Open patients had higher rates of major adverse cardiac events (20.2% vs 4.4%; P < .001), pulmonary complications (12.8% vs 1.6%; P < .001), non-home discharges (28.5% vs 7.9%; P < .001), and 30-day mortality (4.5% vs 1.4%; P < .001). There were no differences in early survival, but open repair had better middle and late survival compared with EVAR over the course of 5 years. A total of 74 EVAR patients (2.4%) had reinterventions during the study period. EVAR patients that required interventions had higher 1-year (40.5% vs 7.3%; P < .001) and 5-year mortality (43.2% vs 14.1%; P < .001) compared with those that did not require reinterventions. EVAR patients who had reinterventions had higher 1-year (40.5% vs 6.3%; P < .001) and 5-year (43.2% vs 20.3%; P = .006) mortality compared with their matched open cohort. ConclusionsPatients undergoing EVAR for AAAs who are deemed unfit for open repair have better perioperative morbidity and mortality compared with open repair. However, patients who had an open repair had better middle and late survival over the course of 5 years. The categorization of unfitness for open surgery may be inaccurate and re-evaluation of this terminology/concept should be undertaken.

Operation time and clinical outcomes for open infrarenal abdominal aortic aneurysms to remain stable in the endovascular era.

Endovascular aortic repair (EVAR) has become a routine procedure worldwide. Ultimately, the increasing number of EVAR cases entails changing conditions for open surgical repair (OSR) regarding patient selection, complexity, and surgical volume. This study aimed to assess the time trends of open abdominal aortic aneurysm (AAA) repair in a high-volume single center in Austria over a period of 20 years, focusing on the operation time and clinical outcomes. A retrospective analysis of all patients treated for infrarenal AAAs with OSR or EVAR between January 2000 and December 2019 was performed. Infrarenal AAA was defined as the presence of a >10-mm aortic neck. Cases with ruptured or juxtarenal AAAs were excluded from the analysis. Two cohorts of patients treated with OSR at different time periods, namely, 2000-2009 and 2010-2019, were assessed regarding demographical and procedure details and clinical outcomes. The time periods were defined based on the increasing single-center trend toward the EVAR approach from 2010 onward. A total of 743 OSR and 766 EVAR procedures were performed. Of OSR cases, 589 were infrarenal AAAs. Over time, the EVAR to OSR ratio was stable at around 50:50 (p = 0.488). After 2010, history of coronary arterial bypass (13.4% vs. 7.2%, p = 0.027), coronary artery disease (38.1% vs. 25.1%, p = 0.004), peripheral vascular disease (35.1% vs. 21.3%, p = 0.001), and smoking (61.6% vs. 34.3%, p < 0.001) decreased significantly. Age decreased from 68 to 66 years (p = 0.023). The operation time for OSR remained stable (215 vs. 225 min, first vs. second time period, respectively, p = 0.354). The intraoperative (5.8% vs. 7.2%, p = 0.502) and postoperative (18.3% vs. 20.8%, p = 0.479) complication rates also remained stable. The 30-day mortality rate did not change over both time periods (3.0% vs. 2.4%, p = 0.666). Balanced EVAR to OSR ratio, similar complexity of cases, and volume over the two decades in OSR showed stable OSR time without compromise in clinical outcomes.

Symptomatic peripheral artery disease increases risk of perioperative mortality following open abdominal aortic aneurysm repair

ObjectivePeripheral artery disease (PAD) is associated with worse survival following abdominal aortic aneurysm (AAA) repair. However, little is known about the impact of PAD and sex on outcomes following open infrarenal AAA repair (OAR). MethodsAll elective open infrarenal AAA cases were queried from the Society for Vascular Surgery Vascular Quality Initiative from 2003 to 2022. PAD was defined as history of non-cardiac arterial bypass, non-coronary percutaneous vascular intervention (PVI), or non-traumatic major amputation. Cohorts were stratified by sex and history of PAD. Multivariable logistic regression and Cox proportional hazards models were constructed to assess the primary endpoints: 30-day and 5-year mortality, respectively. ResultsOf 4910 patients who underwent elective OAR, 3421 (69.7%) were men without PAD, 298 (6.1%) were men with PAD, 1098 (22.4%) were women without PAD, and 93 (1.9%) were women with PAD. Men with PAD had prior bypass (45%), PVI (62%), and amputation (6.7%). Women with PAD had prior bypass (32%), PVI (76%), and amputation (5.4%). Thirty-day mortality was significantly higher in men with PAD compared with men without PAD (4.4% vs 1.7%; P = .001) and in women with PAD compared with women without PAD (7.5% vs 2.4%; P = .01). After risk adjustment, when compared with men without PAD, women with PAD had nearly four times the odds of 30-day mortality (odds ratio, 3.86; 95% confidence interval [CI], 1.55-9.64; P = .004) and men with PAD had almost three times the odds of 30-day mortality (odds ratio, 2.77; 95% CI, 1.42-5.40; P = .003). Five-year survival was 87.8% in men without PAD, 77.8% in men with PAD, 85% in women without PAD, and 76.2% in women with PAD (P < .001). After risk adjustment, only men with PAD had an increased hazard of death at 5 years (hazard ratio, 1.52; 95% CI, 1.07-2.17; P = .019) compared with men without PAD. ConclusionsPAD is a potent risk factor for increased perioperative mortality in both men and women following OAR. In women, this equates to nearly four times the odds of perioperative mortality compared with men without PAD. Future study evaluating risk/benefit is needed to determine if women with PAD reflect a high-risk cohort that may benefit from a more conservative OAR threshold for treatment.

Cross-clamp location and perioperative outcomes after open infrarenal abdominal aortic aneurysm repair: A Vascular Quality Initiative® review.

By analyzing national Vascular Quality Initiative (VQI) data for patients undergoing open infrarenal abdominal aortic aneurysms (AAA) repair, we sought to better characterize the effects of different suprarenal clamping positions on postoperative outcomes. We performed a retrospective analysis of a prospectively collected national VQI database for all open infrarenal AAA repairs performed between 2003 and 2017. Patients were initially divided into proximal (above 1 renal, above 2 renals, and supraceliac) and infrarenal clamp groups. Patients were then subdivided into those who underwent surgery between 2003-2010 and those who had surgery between 2011-2017. Univariate followed by multivariate analyses were done to compare the baseline characteristics, preoperative, intraoperative, and postoperative outcomes between the two groups. During the study period, 9068 open AAA repairs were recorded in the VQI; of these, 5043 met the inclusion criteria. Aortic clamp level was infrarenal in 59% (N = 2975), above 1 renal in 15% (N = 735), above both renals in 21% (N = 1053), and supraceliac in 5% (N = 280). The average age was 69 years, and males comprised 73% (N = 3701) of the cohort. The overall 30-day mortality for the entire study group was 2.7%. On univariate analysis, patients who underwent proximal clamping had significantly higher 30-day mortality than those undergoing infrarenal clamping (3.7 vs 2.0%, p < 0.001). After adjusting for preoperative and intraoperative variables, this difference became nonsignificant. On multivariate analysis, clamping above both renals or the celiac artery was associated with an increased occurrence of postoperative myocardial infarction (odds ratio = 1.44, p = 0.037 and odds ratio = 1.78, p = 0.023, respectively). All proximal clamp positions were associated with a significant increase in the incidence of AKI and renal failure requiring dialysis. There was no significant difference when looking at overall survival times comparing the suprarenal and infrarenal clamp position groups (p = 0.1). Patients who underwent surgery in the latter half of the study period had longer intraoperative renal ischemia time, increased in estimated blood loss, and longer total procedure time. Suprarenal clamping, at any level, was associated with an increased risk of AKI and renal replacement therapy. Clamping above both renal and celiac arteries was associated with increased cardiac morbidity. Perioperative and long-term mortality was unaffected by clamp level. Patients operating in the latter half of the study had increased estimated blood loss, renal ischemia time, and operative time, which may reflect decreased training in open AAA repair. During open AAA repair, the proximal clamp site should be chosen based on anatomic considerations and not a perceived perioperative mortality benefit. Proximal aortic clamping should always be performed at the safest, distal-most level to reduce cardiac morbidity and the risk of postoperative dialysis.

Endovascular Treatment of Aortic Bifurcation Occlusive Disease 10 Years After Open Surgical Repair of an Infrarenal Abdominal Aortic Aneurysm

A 74 year old man, a moderate smoker treated 10 years previously by open infrarenal abdominal aortic aneurysm tube graft, presented with left leg rest pain. (A) Computed tomography angiography revealed dilatation of the infrarenal aortic segment (31 mm) with a newly developed left common iliac artery occlusion and right common iliac artery sub-occlusion. (B) Two balloon expandable stents (8 × 59 mm; Omnilink Elite [Abbott Vascular, Santa Clara, CA, USA]) were deployed in a kissing stent configuration with good results and no complications. The patient received dual antiplatelet therapy for three months and after this period was asymptomatic.Image 1

Red blood cell transfusion associated with increased morbidity and mortality in patients undergoing elective open abdominal aortic aneurysm repair.

BackgroundRed blood cell (RBC) transfusions are associated with increased mortality and morbidity. The aim of this analysis was to examine the association between RBC transfusions and long-term survival for patients undergoing elective open infrarenal abdominal aortic aneurysm (AAA) repair with up to 15 years of follow-up.MethodsProspective cohort study using data from The Danish Vascular Registry from 2000–2015. Primary endpoint was all-cause mortality. Secondary endpoints were in-hospital complications. Transfused patients were divided into subgroups based on received RBC transfusions (1, 2–3, 4–5 or > 5). Using Cox regression multi-adjusted analysis, non-transfused patients were compared to transfused patients (1, 2–3, 4–5, >5 transfusions) for both primary and secondary endpoints.ResultsThere were 3 876 patients included with a mean survival of 9.1 years. There were 801 patients who did not receive transfusions. Overall 30-day mortality was 3.1% (121 patients) and 3.6% (112) for all transfused patients. For the five subgroups 30-day mortality was: No transfusions 1.1% (9 patients), 1 RBC 1.2% (4 patients), 2–3 RBC 2.2% (26 patients), 4–5 RBC 1.9% (14 patients) and > 5 RBC 7.9% (68 patients). After receiving RBCs, the hazard ratio for death was 1.54 (95% CI 1.27–1.85) compared to non-transfused patients. There was a significant increase in mortality when receiving 2–3 RBC: HR 1.32 (95% CI 1.07–1.62), 4–5 RBC: 1.64 (1.32–2.03) and >5 RBC: 1.96 (1.27–1.85) in a multi-adjusted model.ConclusionThere is a dose-dependent association between RBC transfusions received during elective AAA repair and an increase in short- and long-term mortality. Approximately 25% of included patients had preoperative anemia. These findings should raise awareness regarding potentially unnecessary and harmful RBC transfusions.

Limb Remote Ischemic Preconditioning for Intestinal and Pulmonary Protection during Elective Open Infrarenal Abdominal Aortic Aneurysm Repair: A Randomized Controlled Trial: Erratum.

Limb Remote Ischemic Preconditioning for Intestinal and Pulmonary Protection during Elective Open Infrarenal Abdominal Aortic Aneurysm Repair: A Randomized Controlled Trial: Erratum.

Changes in the sublingual microcirculation following aortic surgery under balanced or total intravenous anaesthesia: a prospective observational study

BackgroundIn vascular surgery with aortic cross-clamping, ischemia/reperfusion injury induces systemic haemodynamic and microcirculatory disturbances. Different anaesthetic regimens may have a varying impact on tissue perfusion. The aim of this study was to explore changes in microvascular perfusion in patients undergoing elective open abdominal aortic aneurysm repair under balanced or total intravenous anaesthesia.MethodsProspective observational study. Patients undergoing elective open infrarenal abdominal aortic aneurysm repair received balanced (desflurane + remifentanil, n = 20) or total intravenous anaesthesia (TIVA, propofol + remifentanil using target-controlled infusion, n = 20) according to the clinician’s decision. A goal-directed haemodynamic management was applied in all patients. Measurements were obtained before anaesthesia induction (baseline) and at end-surgery and included haemodynamics, arterial/venous blood gases, sublingual microvascular flow and density (incident dark field illumination imaging), peripheral muscle tissue oxygenation and microcirculatory reactivity (thenar near infrared spectroscopy with a vascular occlusion test).ResultsThe two groups did not differ for baseline characteristics, mean aortic-clamping time and requirement of vasoactive agents during surgery. Changes in mean arterial pressure, systemic vascular resistance index, haemoglobin and blood lactate levels were similar between the two groups, while the cardiac index increased at end-surgery in patients undergoing balanced anaesthesia. The sublingual microcirculation was globally unaltered in the TIVA group at end-surgery, while patients undergoing balanced anaesthesia showed an increase in the total and perfused small vessel densities (from 16.6 ± 4.2 to 19.1 ± 5.4 mm/mm2, p < 0.05). Changes in microvascular density were negatively correlated with changes in the systemic vascular resistance index. The area of reactive hyperaemia during the VOT increased in the balanced anaesthesia group (from 14.8 ± 8.1 to 25.6 ± 14.8%*min, p < 0.05). At end-surgery, the tissue haemoglobin index in the TIVA group was lower than that in the balanced anaesthesia group.ConclusionsIn patients undergoing elective open abdominal aortic aneurysm repair with a goal-directed hemodynamic management, indices of sublingual or peripheral microvascular perfusion/oxygenation were globally preserved with both balanced anaesthesia and TIVA. Patients undergoing balanced anaesthesia showed microvascular recruitment at end-surgery.Trial registrationNCT03510793, https://www.clinicaltrials.gov, date of registration April 27th 2018, retrospectively registered.

Inferior mesenteric artery replantation does not decrease the risk of ischemic colitis after open infrarenal abdominal aortic aneurysm repair

BackgroundIschemic colitis after an open abdominal aortic aneurysm (AAA) repair remains a serious complication with a nationally reported rate of 1% to 6% in elective cases and up to 60% after an aneurysmal rupture. To prevent this serious complication, inferior mesenteric artery (IMA) replantation is performed at the discretion of the surgeon based on his or her intraoperative findings, despite the lack of clear evidence to support this practice. The purpose of this study was to determine whether replantation of the IMA reduces the risk of ischemic colitis and improves the overall outcome of AAA repair. MethodsPatients who underwent open infrarenal AAA repair were identified in the multicenter American College of Surgeons National Surgical Quality Improvement Program Targeted AAA Database from 2012 to 2015. Emergency cases, patients with chronically occluded IMAs, ruptured aneurysms with evidence of hypotension, and patients requiring visceral revascularization were excluded. The remaining elective cases were divided into two groups: those with IMA replantation (IMA-R) and those with IMA ligation. We measured the 30-day outcomes including mortality, morbidity, and perioperative outcomes. A multivariable logistic regression model was used for data analysis, adjusting for clinically relevant covariates. ResultsWe identified 2397 patients who underwent AAA repair between 2012 and 2015, of which 135 patients (5.6%) had ischemic colitis. After applying the appropriate exclusion criteria, there were 672 patients who were included in our study. This cohort was divided into two groups: 35 patients with IMA-R and 637 patients with IMA ligation. There were no major differences in preoperative comorbidities between the two groups. IMA-R was associated with increased mean operative time (319.7 ± 117.8 minutes vs 242.4 ± 109.3 minutes; P < .001). Examination of 30-day outcomes revealed patients with IMA-R had a higher rate of return to the operating room (20.0% vs 7.2%; P = .006), a higher rate of wound complications (17.1% vs 3.0%; P = .001), and a higher incidence of ischemic colitis (8.6% vs 2.4%; P = .027). There were no significant differences in mortality, pulmonary complications, or renal complications between the two groups. In multivariable analysis, IMA-R was a significant predictor of ischemic colitis and wound complications. ConclusionsThese data suggest that IMA-R is not associated with protection from ischemic colitis after open AAA repair. The role of IMA-R remains to be identified.

Elevated Renal Oxygen Extraction During Open Abdominal Aortic Aneurysm Repair Is Related to Postoperative Renal Dysfunction.

Open abdominal aortic aneurysm repair is often followed by elevated plasma creatinine, likely due to impaired renal blood flow. We evaluated whether postoperative elevation in creatinine relates to renal oxygen extraction during surgery as an index of renal blood flow and also monitored frontal lobe oxygenation. For 19 patients (66 ± 10 years; mean ± SD) undergoing open infrarenal abdominal aortic aneurysm repair, renal oxygen extraction was determined by arterial and renal vein catheterization. Near-infrared spectroscopy determined frontal lobe oxygenation. During surgery mean arterial pressure (from 102 ± 14 to 65 ± 11 mm Hg; P < .0001), arterial hemoglobin (from 7.7 ± 0.7 to 6.6 ± 0.8 mmol/L; P < 0.0001), and frontal lobe oxygenation (from 74 ± 6% to 70 ± 6%; P = .0414) decreased, while renal oxygen extraction increased (from 5.3% [4.3-8.1]; median [interquartile range] to 10.8% [5.8-17.5]; P = .0405). Plasma creatinine became significantly elevated on the second day after the operation (from 83 [73-101] to 105 µmol/L [79-143]; P = .0062) with a peak increase observed after 2 days (1-2). The peak increase in creatinine correlated to intraoperative renal oxygen extraction ( r = 0.51; P = .026). Kidney function was affected after open abdominal aortic aneurysm repair likely related to limited renal blood flow. We take the increase in renal oxygen extraction and reduction in frontal lobe oxygenation to suggest that mean arterial pressure and hemoglobin were too low to maintain renal and cerebral circulation in vascular surgical patients.

Regional Variation in Postoperative Myocardial Infarction in Patients Undergoing Vascular Surgery in the United States

The aim of this study is to assess for regional variation in the incidence of postoperative myocardial infarction (POMI) following nonemergent vascular surgery across the United States to identify potential areas for quality improvement initiatives. We evaluated POMI rates across 17 regional Vascular Quality Initiative (VQI) groups that comprised 243 centers with 1,343 surgeons who performed 75,057 vascular operations from 2010 to 2014. Four procedures were included in the analysis: carotid endarterectomy (CEA, n=39,118), endovascular abdominal aortic aneurysm (AAA) repair (EVAR, n=15,106), infrainguinal bypass (INFRA, n=17,176), and open infrarenal AAA repair (OAAA, n=3,657). POMI was categorized by the method of diagnosis as troponin-only or clinical/ECG and rates were investigated in regions with ≥100 consecutive cases. Regions with significantly different POMI rates were defined as those >1.5 interquartile lengths beyond the 75th percentile of the distribution. Risk-adjusted rates of POMI were assessed using the VQI Cardiac Risk Index all-procedures prediction model to compare the observed versus expected rates for each region. Overall rates of POMI varied by procedure type: CEA 0.8%, EVAR 1.1%, INFRA 2.7%, and OAAA 4.2% (P<0.001). Significant variation in POMI rates was observed between regions, resulting in differing ranges of POMI rates for each procedure: CEA 0.5-2.0% (P=0.001), EVAR 0.3-3.1% (P<0.001), INFRA 1.1-4.8% (P<0.001), and OAAA 2.2-10.0% (P<0.001). A single region in 3 of the 4 procedure-specific datasets was identified as a statistical outlier with a significantly higher POMI rate after CEA, EVAR, and OAAA; this region was identical for the EVAR and OAAA datasets but was a different region for the CEA dataset. No significant variation in POMI was noted between regions after INFRA. Procedure-specific clinical POMI rates (mean; range) were significantly different between regions for EVAR (0.4%; 0-1.1%, P=0.01) and INFRA (1.4%; 0.5-2.9%, P=0.01), but not for CEA (0.4%; 0-0.8%, P=0.53) or OAAA (1.6%; 0-3.8%, P=0.23). Procedure-specific troponin-only POMI rates (mean; range) were significantly different between regions for all procedures: CEA (0.4%; 0.1-1.2%, P<0.001), EVAR (0.7%; 0-2.1%, P<0.001), INFRA (1.3%; 0.4-2.5%, P=0.001), and OAAA (2.5%; 0-8.5%, P<0.001). After risk adjustment, regional variation was again noted with 3 regions having higher and 4 regions having lower than expected rates of POMI. Significant variation in POMI rates following major vascular surgery exists across VQI regions even after risk adjustment. These findings may present an opportunity for focused regional quality improvement efforts.

The perioperative effect of concomitant procedures during open infrarenal abdominal aortic aneurysm repair

Open repair of abdominal aortic aneurysms (AAAs) is occasionally performed in conjunction with additional procedures; however, how these concomitant procedures affect outcome is unclear. This study determined the frequency of additional procedures during elective open AAA repair and the effect on perioperative outcomes. All elective infrarenal open AAA repairs between January 2003 and November 2014 in the Vascular Study Group of New England (VSGNE) were identified. Patients were grouped by concomitant procedures, which included no concomitant procedure, renal artery bypass, lower extremity bypass, other abdominal procedure, or thromboembolectomy. Analyses were performed using multivariable logistic regression. Of 1314 patients who underwent elective AAA repair, 153 (11.6%) had a concomitant procedure, including renal bypass in 27 (2.1%), lower extremity bypass in 28 (2.1%), other abdominal procedures in 64 (4.9%), and thromboembolectomy in 48 (3.7%). Independent risk factors for 30-day mortality were renal bypass (odds ratio [OR], 7.2; 95% confidence interval [CI], 1.9-27.7), other abdominal procedures (OR, 4.8; 95% CI, 1.6-14.1), and thromboembolectomy (OR, 8.8; 95% CI, 3.1-24.9). Deterioration of renal function was predicted by renal bypass (OR, 5.1; 95% CI, 2.1-12.4) and thromboembolectomy (OR, 3.7; 95% CI, 1.8-7.6). Lower extremity bypass and thromboembolectomy were predictive of postoperative leg ischemia (OR, 8.9; 95% CI, 2.7-29.0; OR, 11.2; 95% CI, 4.4-28.8, respectively), and thromboembolectomy was also predictive of postoperative bowel ischemia (OR, 4.4; 95% CI, 1.6-12.0). Performing additional procedures during infrarenal open AAA repair is associated with increased morbidity and mortality in the postoperative period. Careful deliberation of the operative risks and the necessity of the additional interventions are therefore advised during operative planning. This study also highlights the importance of avoiding perioperative thromboembolic events.

Preoperative antiplatelet and statin treatment was not associated with reduced myocardial infarction after high-risk vascular operations in the Vascular Quality Initiative

Medical management with antiplatelet (AP) and statin therapy is recommended for nearly all patients undergoing vascular surgery to reduce cardiovascular events. We assessed the association between preoperative use of AP and statin medications and postoperative in-hospital myocardial infarction (MI) in patients undergoing high-risk open surgery. We studied patients who underwent elective suprainguinal (n = 3039) and infrainguinal (n = 8323) bypass and open infrarenal abdominal aortic aneurysm repair (n = 3007) in the Vascular Quality Initiative (VQI, 2005-2014). We assessed the association between AP or statin use and in-hospital postoperative MI and MI/death. Multivariable logistic analyses were performed to identify the patient, procedure, and preoperative medication factors associated with postoperative MI and MI/death across procedures and patient cardiac risk strata. Secondary end points included bleeding, transfusion, and thrombotic complications. Most patients were taking both AP and statin preoperatively (56% both agents vs 19% AP only, 13% statin only, and 12% neither agent). Use of both agents was more common for patients in the highest cardiac risk stratum (low, 54%; intermediate, 59%; high, 61%; P < .01). Increased cardiac risk was associated with higher MI rates (1.8% vs 3.8% vs 6.5% for low, intermediate, and high risk; P < .01). By univariate analysis, MI rate was paradoxically higher for patients taking both agents (3.7%, vs statin only 2.8%, AP only 2.6%, or neither AP nor statin 2.4%; P = .003). After multivariable adjustment, rates of MI in patients taking preoperative AP only (odds ratio [OR], 0.9; 95% confidence interval [CI], 0.7-1.2) and statin only (OR, 0.8; 95% CI, 0.6-1.2) were not different from those in patients taking either or neither medication (neither agent compared with taking both agents: OR, 1.0; 95% CI, 0.7-1.4; P > .05 for all). Similarly, rates of MI/death were not associated with medication status after multivariable adjustment. Estimated blood loss >1 liter (OR, 2.4; 95% CI, 1.6-3.7; P < .01) and transfusions of 1 or 2 units (OR, 2.5; 95% CI, 2.0-3.3; P < .01) and ≥3 units (OR, 4.0; 95% CI, 3.1-5.3; P < .01) were highly associated with MI, with similar findings related to composite MI/death in multivariable analysis. Rates of blood loss were slightly higher with AP use for all procedures; however, increased transfusions occurred only for infrainguinal bypass with AP use. Rates of reoperation for bleeding, graft thrombosis, or graft revision did not differ by preoperative AP use. Preoperative AP and statin medications as used in VQI were not associated with the rate of in-hospital MI/death after major open vascular operations. Rather, predicted cardiac risk and operative blood loss were significantly associated with in-hospital MI or MI/death. AP and statin medications appear to be more useful in reducing late mortality than early postoperative MI/death in VQI. However, they were not harmful, so their long-term benefit argues for continued use.

Effects of Sevoflurane and Propofol on Intestinal Ischemic Reperfusion Injury in Patients Undergoing Elective Open Infrarenal Abdominal Aortic Aneurysm Repair: A Randomized Controlled Trial

Background: We previously demonstrated that propofol had a protective effect on the intestine at risk after an ischemic injury in a rat model. The current study tested the hypothesis that such beneficial effects, so far mainly seen in the laboratory, are reproducible in humans.Methods: Seventy patients undergoing elective open infrarenal abdominal aortic aneurysm repair were randomized to receive general anesthesia with either propofol or sevoflurane. General anesthesia was induced with 3 µg/kg fentanyl, 0.2 mg/kg cisatracurium, and target-controlled infusion of propofol, set at a plasma target concentration of 4-6 µg/ml, or sevoflurane initially started at 8%. Anesthesia was maintained with target-controlled infusion of propofol (2-4 µg/ml) or sevoflurane (0.8-1.0 minimum alveolar concentration). Except for this, anesthetic and surgical management was the same in both groups. Serum intestinal fatty acid binding protein was taken as the primary outcome for evaluating intestinal injury. The secondary outcomes included other intestinal injury variables (serum endotoxin levels, serum diamine oxidase activity and the score of intestinal injury severity) as well as markers reflecting oxidative stress and systemic inflammatory response.Results: The levels of biomarkers reflecting intestinal injury were higher than baseline in both groups (all P<0.05). However, in sevoflurane-anesthetized patients, these variables increased significantly more than those in patients anesthetized with propofol (all P<0.05), whereas the scores of the intestinal injury severity didn't differ between two groups (P=0.53).Conclusions: Patients receiving propofol for abdominal aortic aneurysm repair surgery had less intestinal injury than patients receiving sevoflurane, which may be related to its better anti-oxidative property. Citation: Cai Li, Wu Yan, Jian- Tong Shen, Shi-Hong Wen, Ke-Xuan Liu. Effects of sevoflurane and propofol on intestinal ischemic reperfusion injury in patients undergoing elective open infrarenal abdominal aortic aneurysm repair: a randomized controlled trial. J Anesth Perioper Med 2015; 2: 126-35. Published on April 30, 2015. doi: 10.24015/JAPM.2015.0018This is an open-access article, published by Evidence Based Communications (EBC). This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium or format for any lawful purpose. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.

Intraoperative Hypothermia is Associated with an Increased Intensive Care Unit Length-of-Stay in Patients Undergoing Elective Open Abdominal Aortic Aneurysm Surgery: A Retrospective Cohort Study

Intraoperative hypothermia in open elective abdominal aortic aneurysm repair may be associated with increased hospital morbidity. This retrospective, single centre study investigated whether there was an association between intraoperative hypothermia in open elective abdominal aortic aneurysm repair and postoperative in-hospital morbidity. The data of 119 patients who underwent open infrarenal abdominal aortic aneurysm repair between January 2006 and January 2011 were collected. The electronic databases from the hospital, intensive care unit, transfusion medicine and operating theatres were linked by the patient's unique identifiers including date of birth and unit record number. Intraoperative nasopharyngeal temperature measurements were collected manually from paper-based anaesthetic records. The study group included 102 out of the 119 patients. Sixty-six patients (64.6%) had intraoperative hypothermia as defined by temperature <36°C. Intraoperative temperature was not predictive of hospital length-of-stay or any of the other perioperative complications such as acute renal failure, acute respiratory complications, acute myocardial infarction, transfusion requirements or postoperative infection. In the normothermic group, the number of hours in the intensive care unit was 35% lower (ratio of means=0.65; 95% confidence interval 0.51 to 0.84; P=0.0008), even after adjusting for possible confounders such as age, duration of anaesthesia, size of aneurysm, comorbidities and transfusion. Intraoperative hypothermia is a persisting problem and more aggressive warming strategies may need to be identified and employed to achieve normothermia.

Risk factors for predicting postoperative complications after open infrarenal abdominal aortic aneurysm repair: results from a single vascular center in China

Study ObjectiveTo identify the risk factors of, and develop a prediction model for, postoperative complications of patients undergoing infrarenal abdominal aortic aneurysm (IAAA) repair. DesignRetrospective analysis. SettingVascular surgery center of a university hospital. MeasurementsThe clinical data of 316 IAAA cases were collected from January 2004 to October 2010 at a single vascular center in China. Postoperative complications were observed within 30 days after surgery. Patient-specific and operation-specific characteristics were analyzed in relation to postoperative complications using multiple logistic regression analysis. Main ResultsOverall incidence of postoperative complications and overall 30-day mortality of IAAA repair patients were 48.4% (153/316) and 8.8% (28/316), respectively. Postoperative complications involved pulmonary (18.9%), cardiac (14.2%), renal (7.3%), gastrointestinal (5.4%), neurologic (1.3%), and hepatic (0.9%) systems, and acute arterial embolism of the lower limb occurred in 1.3% of cases. Risk factors were age [> 65 yrs; odds ratio (OR) 1.6], aortic occlusion time (> 90 min; OR 2.4), history of chronic obstructive pulmonary disease (COPD; OR 4.4), emergency operation (OR 6.1), and history of cardiac dysfunction (OR 2.1). ConclusionsA combination of age, COPD, emergency operation, history of cardiac dysfunction and aortic occlusion time has significant impact on postoperative complications after open IAAA repair.

Development of a risk index for prediction of mortality after open aortic aneurysm repair

Open infrarenal abdominal aortic aneurysm (oAAA) repair is associated with significant morbidity and mortality. Although there has been a shift toward endovascular repair, many patients continue to undergo an open repair due to anatomic considerations. Tools currently existing for estimation of periprocedural risk in patients undergoing open aortic surgery have certain limitations. The objective of this study was to develop a risk index to estimate the risk of 30-day perioperative mortality after elective oAAA repair. Patients who underwent elective oAAA repair (n = 2845) were identified from the American College of Surgeons' 2007 to 2009 National Surgical Quality Improvement Program (NSQIP), a prospective database maintained at >250 centers. Univariable and multivariable analyses were performed to evaluate risk factors associated with 30-day mortality after oAAA repair and a risk index was developed. The 30-day mortality after oAAA repair was 3.3%. Multivariable analysis identified six preoperative predictors of mortality, and a risk index was created by assigning weighted points to each predictor using the β-coefficients from the regression analysis. The predictors included dyspnea (at rest: 8 points; on moderate exertion: 2 points; none: 0 points), history of peripheral arterial disease requiring revascularization or amputation (3 points), age >65 years (3 points), preoperative creatinine >1.5 mg/dL (2 points), female gender (2 points), and platelets <150,000/mm(3) or >350,000/mm(3) (2 points). Patients were classified as low (<7%), intermediate (7%-15%), and high (>15%) risk for 30-day mortality based on a total point score of <8, 8 to 11, and >11, respectively. There were 2508 patients (88.2%) patients in the low-risk category, 278 (9.8%) in the intermediate-risk category, and 59 (2.1%) in the high-risk category. This risk index has excellent predictive ability for mortality after oAAA repair and awaits validation in subsequent studies. It is anticipated to aid patients and surgeons in informed patient consent, preoperative risk assessment, and optimization.

Limb Remote Ischemic Preconditioning for Intestinal and Pulmonary Protection during Elective Open Infrarenal Abdominal Aortic Aneurysm Repair

Remote ischemic preconditioning (RIPC) may confer the cytoprotection in critical organs. The authors hypothesized that limb RIPC would reduce intestinal and pulmonary injury in patients undergoing open infrarenal abdominal aortic aneurysm repair. In this single-center, prospective, double-blinded, randomized, parallel-controlled trial, 62 patients undergoing elective open infrarenal abdominal aortic aneurysm repair were randomly assigned in a 1:1 ratio by computerized block randomization to receive limb RIPC or conventional abdominal aortic aneurysm repair (control). Three cycles of 5-min ischemia/5-min reperfusion induced by a blood pressure cuff placed on the left upper arm served as RIPC stimulus. The primary endpoint was arterial-alveolar oxygen tension ratio. The secondary endpoints mainly included the intestinal injury markers (serum intestinal fatty acid-binding protein, endotoxin levels, and diamine oxidase activity), the markers of oxidative stress and systemic inflammatory response, and the scores of the severity of intestinal and pulmonary injury. In limb RIPC group, a/A ratio was significantly higher than that in control group at 8, 12, and 24 h after cross-clamp release (66 ± 4 vs. 45 ± 4, P = 0.003; 60 ± 6 vs. 37 ± 4, P = 0.002; and 60 ± 5 vs. 47 ± 6, P = 0.039, respectively). All biomarkers reflecting intestinal injury increased over time, and there was significant differences between limb RIPC and control group (P < 0.001). The severity of intestinal and pulmonary injury was decreased by limb RIPC (P = 0.014 and P = 0.001, respectively). Limb RIPC attenuates intestinal and pulmonary injury in patients undergoing elective open infrarenal abdominal aortic aneurysm repair without any potential risk.