High-risk Vascular Surgery Research Articles

Implementing primary care follow-up for high-risk vascular surgery patients

Background: The Centers for Medicare and Medicaid Services consider the 30-day hospital readmission rate an outcome of care measure; a high rate is associated with high-cost and bed utilization. Purpose: The Division of Vascular Surgery at a large academic medical center implemented a 15-week quality improvement project in the fall of 2022 to reduce readmissions among patients deemed high-risk for readmission and discharged to home. Methods: The discharging provider utilized the “HOSPITAL Score for Readmission” tool to identify patients at high-risk for unplanned 30-day readmission to receive the intervention, which included follow-up with a primary care provider (PCP) within two weeks of hospital discharge to address non-surgical medical conditions that may have been exacerbated during the hospital stay. A hospital based transitional care clinic bridged medical care for identified patients without an established PCP or whose PCP could not accommodate an appointment until PCP assumption of care. Discharging providers included 11 nurse practitioners and 2 surgery residents; each received a one-on-one educational teaching session and a weekly reminder e-mail through week 9. Results: A total of 158 vascular surgery patients (low and high-risk) were discharged home over 15 weeks with 30 patients (19%) having an unplanned readmission within 30-days from discharge. Adherence issues with the intervention among staff allowed for the high-risk group to be divided into those who did not receive the intervention versus those who did. The high-risk patients who did not receive the intervention had a higher readmission rate (30.4%) than the high-risk patients who did receive the intervention (21.4%). Conclusions: Numerous acute and chronic medical problems were treated at the PCP/transitional care clinic visits, which may have contributed to the reduction in rate of readmissions occurring within 30-days for those patients. Increased usage of the transitional care clinic identified a gap that patients continue to require assistance with establishing care with a PCP and further process change in the future is needed to ensure successful transition for all patients.

Effect of lidocaine on intraoperative blood pressure variability in patients undergoing major vascular surgery

BackgroundDynamic fluctuations of arterial blood pressure known as blood pressure variability (BPV) may have short and long-term undesirable consequences. During surgical procedures blood pressure is usually measured in equal intervals allowing to assess its intraoperative variability, which significance for peri and post-operative period is still under debate. Lidocaine has positive cardiovascular effects, which may go beyond its antiarrhythmic activity. The aim of the study was to verify whether the use of intravenous lidocaine may affect intraoperative BPV in patients undergoing major vascular procedures.MethodsWe performed a post-hoc analysis of the data collected during the previous randomized clinical trial by Gajniak et al. In the original study patients undergoing elective abdominal aorta and/or iliac arteries open surgery were randomized into two groups to receive intravenous infusion of 1% lidocaine or placebo at the same infusion rate based on ideal body weight, in concomitance with general anesthesia. We analyzed systolic (SBP), diastolic (DBP) and mean arterial blood (MAP) pressure recorded in 5-minute intervals (from the first measurement before induction of general anaesthesia until the last after emergence from anaesthesia). Blood pressure variability was then calculated for SBP and MAP, and expressed as: standard deviation (SD), coefficient of variation (CV), average real variability (ARV) and coefficient of hemodynamic stability (C10%), and compared between both groups.ResultsAll calculated indexes were comparable between groups. In the lidocaine and placebo groups systolic blood pressure SD, CV, AVR and C10% were 20.17 vs. 19.28, 16.40 vs. 15.64, 14.74 vs. 14.08 and 0.45 vs. 0.45 respectively. No differences were observed regarding type of surgery, operating and anaesthetic time, administration of vasoactive agents and intravenous fluids, including blood products.ConclusionIn high-risk vascular surgery performed under general anesthesia, lidocaine infusion had no effect on arterial blood pressure variability.Trial registrationClinicalTrials.gov; NCT04691726 post-hoc analysis; date of registration 31/12/2020.

Palliative Care Consults and Frailty Screening in High-Risk Vascular Surgery Patients

Palliative care has increasingly been integrated into the management of high-risk surgery because of the beneficial effect on patient quality of life. However, the utilization of palliative care in vascular surgery remains unclear due to a lack of data. The purpose of this study was to determine the palliative care consult rate in high-risk vascular surgery patients. A retrospective chart review was performed at a single Veteran Affairs Medical Center from 2013 to 2021. High-risk vascular surgery patients were identified by using the Veterans Affairs Surgical Quality Improvement Program (VASQIP) risk score of >4%, which predicted 30-day mortality. Patient demographics, operative procedures, and clinical outcomes were collected. A total of 126 patients underwent a high-risk vascular surgery operation. The surgical procedures consisted of 78 amputations, 19 bypasses, 18 endovascular aneurysm repair/stents, and 11 thrombectomy/arterial repair. Palliative care was consulted in 44 patients (35%) during the hospitalization: 8 patients (18%) had preoperative consults, whereas 36 patients (82%) had postoperative consults. The overall 30-day mortality was 15%, and the 1-year mortality rate was 34%. The 30-day and 1-year mortality rates were higher in those patients who received palliative care consultation (36% and 64%, respectively) compared with those without consult (0% and 21%, respectively). The palliative care consults had a higher referral rate in more frail patients, by Revised Analysis Index (RAI): n = 13 of 57 (23%) nonfrail (RAI <20), n = 14 of 44 (32%) frail (RAI = 21-32), and n = 17 of 25 (68%) very frail (RAI >33). The majority of the palliative care consults were obtained for goals of care discussion (80%) compared with withdrawal of care (20%). Palliative care is generally underused for vascular surgery patients, but our data demonstrated a palliative care consult rate of 35% in high-risk vascular surgery patients. A frailty screening program can further stratify high-risk vascular surgery patients who would benefit from an early palliative care consult.

Efficacy of Lidocaine Infusion in High-Risk Vascular Surgery—A Randomized, Double-Blind, Placebo-Controlled Single-Center Clinical Trial

In perioperative pain control, adjuvants such as lidocaine can reduce opioid consumption in a specific type of surgery. The aim of this single-center prospective double-blinded randomized controlled trial was to determine opioid consumption in the perioperative period in patients receiving continuous lidocaine infusion. Patients undergoing elective abdominal aorta and/or iliac arteries open surgery were randomized into two groups to receive 1% lidocaine or placebo at the same infusion rate based on ideal body weight (bolus of 0.15 mL/kg during the induction of anesthesia followed by continuous infusion of 0.2 mL/kg/h during surgery; postoperatively 0.1 mL/kg/h for 24 h) additionally to standard opioid analgesia. Total opioid consumption within 24 h after surgery was 89.2 mg (95%CI 80.9-97.4) in the lidocaine and 113.1 mg (95%CI 102.5-123.6) in the placebo group (p = 0.0007). Similar findings were observed in opioid consumption intraoperatively (26.7 mg (95%CI 22.2-31.3) vs. 35.1 mg (95%CI 29.1-41.2), respectively, p = 0.029) and six hours postoperatively (47.5 mg (IQR 37.5-59.5) vs. 60 mg (IQR 44-83), respectively, p = 0.01). In high-risk vascular surgery, lidocaine infusion as an adjunct to standard perioperative analgesia is effective. It may decrease opioid consumption by more than 20% during the first 24 h after surgery, with no serious adverse effects noted during the study period.

Abstract 12636: Association Between Pre-Operative Specialist Assessment and Adverse Outcomes Among Patients Scheduled for Major Vascular Surgery

Background: The impact of pre-operative specialist assessment on outcomes following high-risk vascular surgery remains uncertain. Our objective was to characterize the association between pre-operative cardiology or general internal medicine (GIM) assessment and post-operative outcomes following scheduled major vascular surgery. Methods: This is a population-based cohort study of all adult scheduled major vascular surgery patients in Ontario, Canada (April 1, 2004-March 31, 2019). Those who underwent an ambulatory cardiology and/or GIM assessment within 6 months prior to surgery were compared to those who did not. The primary outcome was 30-day mortality. Secondary outcomes included 30-day mortality, myocardial infarction or stroke; 30-day cardiovascular death; 1-year mortality; 1-year mortality, myocardial infarction or stroke; and 1-year cardiovascular death. Multivariable cox proportional hazard regression using inverse probability of treatment weighting (IPTW) was used to mitigate confounding by indication. Results: Among 50,228 scheduled major vascular surgery patients, 20,484 underwent pre-operative ambulatory specialist assessment: 11,074 (54.1%) with cardiology, 8,071 (39.4%) with GIM and 1,339 (6.5%) with both. Patients who underwent cardiology or GIM assessment had a higher Revised Cardiac Risk Index (N with Index over 2= 4,989 [24.4%] vs. 4,587 [15.4%], p&lt;0.001) and more frequent pre-operative cardiac testing (N=7,772 [37.9%] vs. 6,113 [20.6%], p&lt;0.001) but had lower crude 30-day mortality (N=551 [2.7%] vs. 970 [3.3%], p&lt;0.001). After application of IPTW, pre-operative specialist assessment remained associated with a lower rate of 30-day mortality (Hazard Ratio [95%CI] = 0.73 [0.65-0.82]) and a lower rate of all secondary outcomes (Figure). Conclusion: Pre-operative ambulatory cardiology or GIM assessment is associated with improved outcomes following scheduled major vascular surgery

Prognostic value of preoperative electrocardiography in predicting myocardial injury after vascular surgery.

The current European guidelines recommend that a preoperative electrocardiogram (ECG) should be performed routinely in patients scheduled for high-risk surgery. However, the evidence regarding ECG as a predictor of perioperative cardiac complications is weak. To evaluate the association of preoperative ECG with short- and long-term outcomes in patients undergoing high-risk vascular procedures. This was a substudy of the international Vascular events In noncardiac Surgery patIents cohort evaluatioN (VISION) Study and included consecutive patients undergoing vascular procedures in a single tertiary center. In each patient, a preoperative 12-lead ECG was evaluated by two experienced clinicians following the Polish Cardiac Society recommendations. We performed routine perioperative troponin monitoring at five time points (one preoperative and four postoperative measurements) to evaluate whether preoperative ECG abnormalities are associated with myocardial injury after noncardiac surgery (MINS) and 1-year major adverse cardiovascular events (MACE) including cardiac death, myocardial infarction, and stroke. The study group comprised 348 patients, 80.5% of whom were male and the median age (interquartile range [IQR]) was 65 (59-72) years. The incidence of MINS and 1-year MACE was 18.7% and 14.4%, respectively. Multivariable analysis showed that none of the predefined ECG abnormalities (ST depression, left axis deviation, atrial fibrillation, and bundle branch block) was associated with the incidence of MINS or 1-year MACE. This study confirmed that preoperative ECG abnormalities are frequent in patients undergoing high-risk vascular surgery. However, we did not find evidence supporting the relation between preoperative ECG abnormalities and postoperative adverse cardiac outcomes in high-risk patients.

Descending thoracic aorta to bifemoral bypass grafting in Aortobiiliac occlusive disease

Introduction: The aim of this prospective study is to describe the clinical symptoms, investigation findings and surgical treatment of aortoiliac occlusive disease where abdominal approach not feasible or not possible for aortobifemoral bypass grafting. Method: From May 2013 to May 2019, ten patients were treated with descending thoracic aorto-bifemoral bypass for aortoiliac occlusive disease at Grant Medical College and JJ group of Hospitals, Mumbai (Maharashtra). Total 20 limbs were re-vascularized. Demographic data, co-morbid factors, per operative findings were noted. Indication for surgery is juxtarenal occlusion of the abdominal aorta, in most of the cases. In postoperative period, all patients were evaluated for appearance of distal pulsations, primary patency, warmness of foot, symptom relief, wound infection, healing of the ulcer, and complications. CT angiography was done in follow-up. Maximal followup of two years and minimum followup of one month was done after surgery. Results: No mortality. Mean duration of surgery was 2.5-5 h and mean blood loss was 250 - 400 mL. Major morbidity includes one graft occlusion. None of the patients developed proximal propagation of aortic thrombus. Ulcers showed healing. All patients had a good quality of life postoperatively. Postoperative angiography showed good re-vascularization. Conclusion: Majority of our patients are old age having juxtarenal aortic occlusion so we decided to use DTA as inflow for primary revascularization to avoid entering abdomen and renal injury. Some authors have recommended supraceliac aorta bypass surgery within the retroperitoneal space for juxtarenal aortic occlusive disease but is technically difficult and associated with morbidity. The major limitation to thoracic aorta bifemoral grafting technique is the morbidity rate associated with thoracotomy in a relatively high-risk vascular surgery population. Also, tunnelling in conventional DTA-to-femoral artery bypass is usually a “blind” procedure.For the cardiothoracic surgeon with experience, the use of descending thoracic aorta could be a very good alternative for infrarenal aortic occlusion or extra-anatomic aortoiliac bypass without any morbidity and mortality with good improvement in quality of life.

Predisposition of functional genetic variants of A-kinase anchoring protein 10 toward acquired repolarization disorders in high-risk vascular surgery patients

PurposeWe aimed at assessing the predisposition of A-kinase anchoring protein 10 (AKAP10) polymorphism toward acquired repolarization disorders in high-risk vascular surgery patients.Patients and methodsOne hundred adult patients (age =44–85 years), scheduled for an elective high-risk “open” vascular surgery procedure, were recruited. The electrocardiogram Holter monitor was used to assess repolarization stability from the beginning of the operation up to 24 hours afterward. The AKAP10 gene rs203462 polymorphism and cardiac complications were analyzed.ResultsRepolarization disturbances defined as QT interval duration corrected for heart rate (QTc) interval prolongation >500 ms and QTc interval dispersion >65 ms were recorded in 46 patients. A model of multivariate logistic regression showed that only the presence of allele G of the AKAP10 polymorphism was an independent risk factor for repolarization disturbances in the perioperative period (odds ratio =14.35; 95% CI =4.65–44.23; p<0.0001).ConclusionWhen the acquired QTc interval prolongation or QTc dispersion is associated with AKAP10 polymorphism, it may remain clinically silent.

Incidence of Myocardial Infarction After High-Risk Vascular Operations in Adults

Advances in perioperative cardiac management and an increase in the number of endovascular procedures have made significant contributions to patients and postoperative myocardial infarction (POMI) risk following high-risk vascular procedures. Whether these changes have translated into real-world improvements in POMI incidence remain unknown. To examine the temporal trends of myocardial infarction (MI) following high-risk vascular procedures. A retrospective cohort study was performed using data collected from January 1, 2005, to December 31, 2013, in the American College of Surgeons National Surgery Quality Improvement Program database, to which participating hospitals across the United States report their preoperative, operative, and 30-day outcome data. A total of 90 303 adults who underwent a high-risk vascular procedure-open aortic surgery or infrainguinal bypass-during the study period were identified. Patients were divided into cohorts based on their year of operation, and their baseline cardiac risk factors and incidence of POMI were compared. Cases from 2005 to 2014 in the database were eligible for inclusion if one of their Current Procedural Terminology codes matched any of the operations identified as a high-risk vascular procedure. Data analysis took place from August 1, 2016, to November 15, 2016. The main exposure was the year of the operation. Other variables of interest included demographics, comorbidities, and other risk factors for MI. Primary outcome of interest was the incidence of POMI. Of the 90 303 patients included in the study, 22 836 (25.3%) had undergone open aortic surgery and 67 467 (74.7%) had had infrainguinal bypass. The open aortic cohort comprised 16 391 men (71.9%), had a mean (SD) age of 69.1 (11.5) years, and was predominantly white (18 440 patients [80.8%] self-identified as white race/ethnicity). The infrainguinal bypass cohort included 41 845 men (62.1%), had a mean (SD) age of 66.7 (11.7) years, and had 51 043 patients (75.7%) who self-identified as white race/ethnicity. During the study period, patients who underwent open aortic procedures were more likely to be classified as American Society of Anesthesiologists class IV (7426 patients [32.6%] vs 15 683 [23.3%] for the infrainguinal bypass cohort) or class V (1131 [5.0%] vs 206 [0.3%]; P < .001) and to undergo emergency procedures (4852 [21.3%] vs 4954 [7.3%]; P < .001). The open aortic procedure cohort also experienced significantly higher actual incidence of POMI (464 [3.0%] vs 1270 [1.9%]; P < .001). From 2009 to 2014, the incidence of POMI demonstrated no substantial temporal change (2.7% in 2009 to 3.1% in 2014; P = .64 for trend). Postoperative MI was consistently associated with poor prognosis, with a 3.62-fold (95% CI, 2.25-5.82) to 11.77-fold (95% CI, 6.10-22.72) increased odds of cardiac arrest and a 3.01-fold (95% CI, 2.08-4.36) to 6.66-fold (95% CI, 4.66-9.52) increased odds of mortality. The incidence of MI did not significantly decrease in the past decade and has been consistently associated with worse clinical outcomes. Further inquiry into why advanced perioperative care did not reduce cardiac complications is important to quality improvement efforts.

Perioperative β-Blockers in Patients Undergoing Noncardiac Surgery-Scientific Misconduct and Clinical Guidelines.

β-blocker use in perioperative period of noncardiac surgeries has been a topic of debate since many years. Earlier studies conducted in the 90s showed decreased cardiac adverse events and improved postoperative outcomes with β-blocker use. Based on this, the ACCF and ESC published guidelines strongly supporting β-blocker use. But contemporaneous studies conducted revealed conflicting evidence and have also proven some of the earlier studies to be fraudulent. Although ACCF guidelines have been updated to partially reflect the changes, ESC guidelines continue to support β-blocker use. In light of the ACCF and ESC guidelines supporting β-blocker use in perioperative period of noncardiac surgeries, our aim was to review the available literature and consolidate evidence in this regard. PubMed search was conducted to include relevant studies between 1950 and 2015. We reviewed 24 eligible studies and few debates conducted in this regard. Based on our review, our findings were as follows: β-blockers should be continued throughout perioperative period in patients who were on β-blockers before surgery for other indications such as angina, hypertension, and symptomatic arrhythmias. Preoperative β-blockers are indicated in patients undergoing high risk vascular surgery or those having high preoperative Cardiac Risk Index Score. In patients with intermediate-to-low cardiac risk, the proven benefit is not sufficient enough to suggest universal use. Based on our review, we conclude that the use of β-blockers in perioperative period of noncardiac surgeries should be determined on an individual basis based on risk-benefit analysis. Guideline organizations should update their recommendations based on new evidence.

Randomized Controlled Trial of Negative Pressure Wound Therapy for High-Risk Groin Wounds in Lower Extremity Revascularization

Revascularization of the lower extremity requiring groin incision is associated with a high rate of surgical site infection (SSI). The objective of this study was to assess the effect of negative pressure wound therapy (NPWT) on rates of infection following primary closure of high-risk groin wounds in vascular surgery patients undergoing lower limb revascularization. We performed a randomized controlled trial at an academic tertiary medical center. High-risk groin wounds were defined as having previous femoral artery cutdown, body mass index >30 kg/m2, or major or minor ischemic tissue loss. We randomized patients to NPWT or standard group once the surgical incision was primarily closed. The primary outcome of the study was overall 30-day groin SSI. Our secondary outcomes were length of stay, readmissions, reoperations, amputations, and mortality. A total of 101 patients were randomized during 13 months. Criteria for inclusion were previous femoral artery cutdown in 24%, >30 kg/m2 body mass index in 36%, and ischemic tissue loss in 40%. The most common revascularization procedure performed was femoral to distal bypass (51%), followed by femoral to femoral artery bypass (20%) and other (29%). Primary outcome of 30-day SSI showed a lower trend but was nonsignificant in the NPWT group (11%) compared with the standard dressing group (19%; P = .24). There was one in-hospital SSI in both groups (P = .96). Length of hospital stay was significantly shorter for the NPWT group compared with the standard group (6.4 days vs 8.9 days; P = .01). We found a trend toward lower groin SSI in high-risk vascular surgery patients treated with NPWT compared with standard dressing. The NPWT group had significantly shorter length of hospital stay than the standard group. Our study was underpowered because of lower than expected infection rates.

Hospitalist-vascular surgery comanagement: effects on complications and mortality

ABSTRACTObjectives: Hospitalized vascular surgery patients have multiple severe comorbidities, poor functional status, and high perioperative cardiac risk. Thus they may be ideal patients for a collaborative care model. However, there is little evidence for a comanagement model on clinical outcomes.Methods: The two-year pre-post study consisted of a comanagement model where a hospitalist actively participated in the medical care of American Society of Anesthesiologist Physical Status Classification scale 3 or 4 vascular surgery patients. Outcomes were in-hospital mortality, length of stay, 30-day readmission rate, pain scores, and patient safety metrics.Results: With comanagement, patient complications decreased from 3.5 to 2.2 events per 1000 patients. (p = 0.045). Mortality decreased from 2.01% to 1.00% (p = 0.049), corresponding to a decrease in the risk-adjusted observed to expected mortality rate ratio from 1.22 to 0.53 (p = 0.01). Patient reported pain scores improved; more patients in the comanagement cohort expressed no pain (72% vs 82.8%; p = 0.01) and there were reductions in reports of mild and moderate pain. There was no significant difference in the risk-adjusted length of stay (observed to expected ratio 0.83 to 0.88 for the pre-intervention and comanagement groups, respectively, p = 0.48). The 30-day readmission rate was unchanged (21.9 vs 20.6% p = 0.44). Patients in the intervention period were more clinically complex, as evidenced by the greater case mix index (2.21 vs 2.44).Conclusions: After two years of implementation, our comanagement service reduced complications, mortality, and pain scores among high-risk vascular surgery patients.

Is the Mortality Benefit With Empagliflozin in Type 2 Diabetes Mellitus Too Good To Be True?

Signaling a likely end to a long and elusive quest for cardiovascular outcome benefit associated with treatment intervention in type 2 diabetes mellitus, the results of the EMPA-REG OUTCOME trial [BI 10773 (Empagliflozin) Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients] were received with a standing ovation at the European Association for the Study of Diabetes scientific meeting in Stockholm, Sweden, on September 17, 2015.1 Witnessing the spontaneous applause, I had mixed emotions. Was it time to bring the trumpets out and rejoice that the “holy grail” had finally been achieved? Or, was it more appropriate to curb the enthusiasm and question the “historic milestone,” given that the mortality benefit was unexpected and unprecedented? Examples abound of instances where we have been led astray by implausibly large treatment effects that were not confirmed by subsequent trials. Perhaps the most compelling is the case of perioperative β-blockade with bisoprolol in high-risk vascular surgery.2 The DECREASE 1 trial (Dutch Echocardiographic Cardiac Risk Evaluation Applying Stress Echo) yielded a 91% risk reduction in cardiovascular death or myocardial infarction ( P <0.001) in 112 patients. These results were widely disseminated and adopted by several practice guidelines, ultimately rising to the status of a performance measure. The positive results of this trial were never replicated. On the contrary, a large, randomized trial (POISE [Perioperative Ischemic Evaluation]) and a meta-analysis pointed to harm, necessitating a downgrading of recommendations a decade after the publication of the original trial results.3 One systematic review concluded that most large treatment effect estimates should be considered with caution. The vast majority are either spurious …

Perioperative Complications are Associated With Adverse Long-Term Prognosis and Affect the Cause of Death After General Surgery.

BackgroundIt is unclear how mortality and causes of death vary between patients and surgical procedures and how occurrence of postoperative complications is associated with prognosis. This study describes long-term mortality rates and causes of death in a general surgical population. Furthermore, we explore the effect of postoperative complications on mortality.MethodsA single-centre analysis of postoperative complications, with mortality as primary endpoint, was conducted in 4479 patients undergoing surgery. We applied univariate and multivariable regression models to analyse the effect of risk factors, including surgical risk and postoperative complications, on mortality. Causes of death were also explored.Results75 patients (1.7 %) died within 30 days after surgery and 730 patients (16.3 %) died during a median follow-up of 6.3 years (IQR 5.8–6.8). Significant differences in long-term mortality were observed with worst outcome for patients undergoing high-risk vascular surgery (HR 1.5; 95 % CI 1.2–1.9). When looking at causes of death, high-risk surgery was associated with a twofold higher risk of cardiovascular death (HR 1.9; 95 % CI 1.2–3.1), whereas the intermediate-risk group had a higher risk of dying from cancer-related causes (HR 1.5; 95 % CI 1.1–2.0). Occurrence of complications—particularly of cardiovascular nature— was associated with worse survival (HR 1.9; 95 % CI 1.3–2.7).ConclusionHigh-risk vascular surgery and occurrence of postoperative complications are important predictors of late mortality. Further focus on these groups of patients can contribute to reduced morbidity. Improvement in quality of care should be aimed at preventing postoperative complications and thus a better outcome in a general surgical population.

Diagnosis, Incidence, and Clinical Implications of Perioperative Myocardial Injury in Vascular Surgery.

Routine measurement of cardiac biomarkers such as troponin T (TnT) is recommended perioperatively, especially in high-risk vascular surgery. Long-term prognosis is worse even in those with nonspecific perioperative myocardial injury. However, a clear understanding of these biomarker profiles and how they should affect patient management is lacking. We examined the perioperative profile of high-sensitivity TnT (hsTnT) release in 85 patients undergoing elective major vascular surgery. Plasma hsTnT was measured preoperatively, at 6, 12, and 24 hours postoperatively, and then every 24 hours for a maximum of 5 days. Significant elevations in hsTnT with/without clinical indicators of ischemia were used to diagnose myocardial infarction or injury. A high incidence of myocardial injury was evident (46% had elevated hsTnT); only 5% were associated with myocardial infarction, and 41% were due to myocardial injury. This study emphasizes the high incidence of perioperative myocardial injury and stress in vascular surgery as revealed by the use of the robust and very sensitive biomarker of myocardial damage, hsTnT. The high availability and swift development of increasingly sensitive assays allow detection of abnormal elevated hsTnT levels in a higher proportion of the population. Consequent challenges are the reduced specificity to separate acute events as well as to deduce the prognostic value of elevations due to confusing criteria; this is especially the case in a patient group with multiple comorbidities that affect hsTnT levels chronically.

Effect of Hydroxyethyl Starch on Outcomes in High-Risk Vascular Surgery Patients: A Retrospective Analysis.

To assess the effect of using hydroxyethyl starch (HES) for intraoperative fluid therapy on outcomes in high-risk vascular surgery patients. Retrospective case series. Single-center academic hospital. The study included 1,395 adult vascular surgery patients with peripheral vascular disease. Retrospective review of hospital databases. Outcomes were compared between patients who were intraoperatively administered HES (Voluven [Fresenius Kabi, Bad Homburg, Germany] or Pentaspan [Bristol-Myers Squibb Canada, Montreal, Quebec, Canada]) versus patients who received only crystalloids during their procedure. Logistic regression was used to assess for association between these groups and mortality (in-hospital, 30-day), intensive care unit admission, hemodialysis requirement, vasopressor requirement, and ventilator requirement. Overall, 796 patients had complete fluid records and were included in the analysis. After adjustment for potential confounders, receiving an HES solution was associated with increased likelihood of 30-day mortality (odds ratio [OR] 2.11, 95% confidence interval [CI] 1.05-3.80), postoperative requirement for hemodialysis (OR 6.17, 95% CI 1.09-35.10), intensive care unit admission (OR 3.52, 95% CI 2.15-5.74), and mechanical ventilation (OR 3.16, 95% CI 1.84-5.41). Intraoperative administration of HES was associated with an increased likelihood of adverse outcomes compared with use of crystalloids alone.

Temporary Axillorenal Bypass in Complex Aorto-Renal Surgery

Prolonged renal ischemia during vascular surgery carries high morbidity and mortality. We report an alternative technique for maintaining renal circulation during suprarenal aortic or renal artery clamping. Between October 2007 and May 2012, 16 patients undergoing aorto-renal surgery (13 men, 3 women) were operated using temporary axillorenal bypass. Operations were performed for supra- and juxtarenal aortic aneurysms (11), occlusive aortic disease (2), renal artery stenoses (2), and abdominal myofibroblastic tumor (1). In elective cases, axillorenal bypass was planned, when prolonged renal ischemia was expected based on preoperative information. Preoperative risk factors (renal dysfunction, hypertension, coronary disease, diabetes, smoking) and intraoperative variables (operating time, blood loss, renal ischemia time) were assessed and compared with postoperative kidney function (serum creatinine, urine output, dialysis) and in-hospital or 30-day-mortality. Even though renal blood flow was restored between clampings, the total cumulative ischemia time was used in analysis. Acute renal failure postoperatively was based on RIFLE criteria. Preoperatively, 44% (7) of the patients had normal renal function (S-crea ≤ 100mmol/L). Renal function was moderately present in 50% (8) (S-crea 100-200mmol/L) and severely in 6% (1) (S-crea ≥ 200mmol/L). Median operation time was 393min (251-535min) and median renal ischemia time was 24.5min (range 8-50min). Transient acute renal dysfunction occurred in 6 (38%) patients, and 4 of them had renal insufficiency preoperatively. Transient renal replacement therapy was needed in 1 (6%) patient only. In 1-month control, postoperative renal function had returned to its baseline level or improved and in-hospital or 30-day mortality was zero. Temporary axillorenal bypass is a considerable option to minimize renal ischemia time during high-risk vascular surgery.

Abstract 14566: Mild Elevation in Cardiac Troponin T is Independently Associated With Long-Term Mortality After Intermediate or High-Risk Vascular Surgery

Introduction: Myocardial injury is a risk factor for adverse outcomes after non-cardiac surgery. However, the prevalence of cardiac troponin T (cTnT) sampling after vascular surgery in real-word practice has not been well studied. Further, whether mild perioperative cTnT elevation is associated with long-term mortality is not established. Methods: This was a retrospective study of 13,196 patients who underwent intermediate or high-risk vascular surgery at a single center from January 1, 2010 - May 1, 2015. Patients were assessed for cTnT sampling within 96 hours of surgery. Cumulative 3 year mortality was stratified by absence of cTnT sampling, a normal value of 0.10 ng/mL. Cox proportional hazards analysis was used to adjust mortality for Revised Cardiac Risk Index (RCRI) score and other patient characteristics. Results: Mean age was 66.2±14.4 years, and 5,357 (40.6%) were female. Troponin was sampled in 3,296 (25.0%) patients, and among those 747 (5.7%) were elevated (positive yield 22.7%). There were 1,858 (14.1%) deaths. On Kaplan-Meier analysis, all-cause mortality was greatest with elevated cTnT (p&lt;0.0001, Figure - A) and was higher across degrees of cTnT elevation (p&lt;0.0001, Figure - B). After adjusting for RCRI score, age, gender, and diabetes, degree of cTnT elevation remained independently associated with mortality (Table). Conclusions: The degree of cTnT elevation independently predicts long-term mortality after vascular surgery. Even mild elevations of cTnT above threshold are associated with heightened risk of mortality, which extends well beyond the acute post-operative period.

Haemodynamic effects of phenylephrine commenced prior to induction of anaesthesia in older patients undergoing high-risk vascular surgery

Fall in mean arterial blood pressure (MAP) during anaesthetic induction is common and may result in profound hypotension. Using the LiDCORapid (LiDCO Ltd, UK), we previously demonstrated that the fall in MAP is usually driven by a reduction in stroke volume (SV) that was presumed due to venodilation. Low- dose phenylephrine (PE), a venoconstrictor, commenced immediately prior to induction ameliorated these effects to a significant degree [1]. However, it is important that the pre-induction administration of PE should not cause any marked changes in MAP and CO. We retrospectively studied a group of 40 high-risk patients about to undergo major peripheral vascular surgery where PE was commenced immediately pre-induction. The haemodynamic effects of this dose of PE on MAP, SV and CO were analysed.

Abstract 18554: The Association of Diagnostic Criteria for Myocardial Infarction and Peri-Operative Cardiac Risk Factors in Vascular Surgery Patients

Background: The inclusion of cardiac biomarkers and ST-T changes on electrocardiography in the diagnostic criteria for myocardial infarction (MI) has increased the apparent incidence of infarction in the general population. The impact of re-defining MI on the incidence and risk of peri-operative MI is unclear. We evaluate the association between diagnostic criteria changes and incidence of and risk factors for peri-operative MI in vascular surgery patients. Methods: Patients who underwent non-emergent vascular surgery between 2005 and 2011 were identified from the American College of Surgeons’ National Surgical Quality Improvement Program (NSQUIP) multi-center database. In 2005, MI was defined by new Q-waves on electrocardiography. In 2009, the definition included variable electrocardiographic evidence (ST elevation, new left bundle branch block, or new q-waves) or an elevation of cardiac troponin greater than 3 times the upper level of normal. Baseline characteristics were identified, and yearly incidence of MI was determined. Multivariable regression was used to determine risk factors associated with MI according to the old and new definitions. Results: Of 70,811 patients who underwent vascular surgery between 2005 and 2011, 40,017 (57%) were ≥ 70 years old, and 46,206 (65%) were male. High-risk vascular surgery (open abdominal aortic aneurysm repair or aorto-bifemoral bypass) was performed in 7,359 (10%) patients. Peri-operative MI more than tripled from the 2005-2008 to 2009-2011 time periods (1.5% vs. 0.4%; p&lt;0.001). In multivariable analyses, significant risk factors for MI also changed from the earlier to later model (See Table). Conclusions: Re-defining MI increased the apparent incidence of and number of independent risk factors for peri-operative MI. The diagnostic criteria for MI utilized in prior cardiac risk prediction models should be considered when determining risk in patients undergoing non-emergent vascular surgery.