Vascular surgery critical care: perioperative cardiac optimization to improve survival

Endovascular Treatment versus Open Surgical Repair for Isolated Iliac Artery Aneurysms

Purpose

Endovascular treatment (EVT) has been shown to be effective and safe for isolated iliac artery aneurysms (IAAs). However, concerns remain regarding the lack of consideration to recent advances in perioperative care and surgical techniques, as well as a significant number of re-interventions with EVT. This study compares the outcomes of open surgical repair (OSR) and EVT using recent clinical data.

Materials and Methods

This retrospective, single-center study included patients who underwent OSR or EVT for isolated degenerative IAAs between January 2007 and December 2018. Primary outcomes were procedure time, number of transfusions during admission, length of hospital stay, complications, and number of preserved internal iliac arteries. Secondary outcomes included all-cause and aneurysm-related mortality, and re-intervention rates.

Results

Fifty-eight consecutive patients underwent treatment for isolated IAAs (25 underwent OSR and 33 underwent EVT), with a median follow-up of 75 months (range: 39-133 months). Baseline characteristics were similar between the groups, except for a lower mean age in the OSR group than in the EVT group (66.0±8.2 vs. 73.1±8.6, P=0.003). Both groups had a mild risk of comorbidity severity score. Early complications (within 30 days of the procedure) occurred more frequently in the OSR group, though not statistically significant (24.0% vs. 6.1%, P=0.07). Late complications, including sac expansion and thrombotic occlusion, were significantly more common in the EVT group (15.2% vs. 0%, P=0.04). Re-intervention rate was higher in the EVT group but not statistically significant (9.1% vs. 4.0%, P=0.44). No significant differences were observed in major adverse cardiovascular events and mortality between the groups (P=0.66 and P=0.27), and there were no aneurysm-related deaths.

Conclusion

For patients with mild risk factors, EVT does not offer a survival or re-intervention advantages over OSR in the treatment of isolated IAAs. However, EVT is associated with an increased risk of late complications. Although larger randomized studies are necessary, OSR may be considered the first-line treatment for isolated IAAs in younger and mild-risk patients.

Anesthetic management for lower extremity vascular bypass procedures: The impact of general or regional anesthesia on clinical outcomes

PURPOSE

Postoperative complications after major surgery, especially vascular procedures, are associated with a significant increase in costs and mortality. Previous studies evaluating general anesthesia versus regional or neuraxial anesthesia for infrainguinal bypass have produced conflicting results. The main aim of the present study is to review current evidence on the application of regional or general anesthesia in patients undergoing infrainguinal bypass surgery and its potential favorable effects on postoperative outcomes.

CONTENTS

Patients undergoing vascular surgery often have multiple comorbidities, and it is important to outline both benefits and risks of regional anesthesia techniques. Neuraxial anesthesia in vascular surgery allows overall avoidance of general anesthesia and does provide short-term benefits beyond analgesia. Previous observational studies suggest that neuraxial anesthesia for lower limb revascularization may reduce morbidity and length of stay. However, evidence of long-term benefits is lacking in most procedures and further work is still warranted.

CONCLUSIONS

Neuraxial anesthesia is usually an effective anesthesia technique for infrainguinal bypass surgery. Elderly patients and those with underlying respiratory problems may display some benefit from neuraxial anesthesia. Further evaluation within institutions should be performed to identify which patients would most benefit from regional techniques. Notably, systemic antithrombotic and anticoagulation therapy is common among this population and may affect anesthetic choices.

The influence of cardiac output on propofol and fentanyl pharmacokinetics and pharmacodynamics in patients undergoing abdominal aortic surgery

Cardiac output (CO) is expected to affect elimination and distribution of highly extracted and perfusion rate-limited drugs. This work was undertaken to quantify the effect of CO measured by the pulse pressure method on pharmacokinetics and pharmacodynamics of propofol and fentanyl administrated during total intravenous anesthesia (TIVA). The data were obtained from 22 ASA III patients undergoing abdominal aortic surgery. Propofol was administered via target-controlled infusion system (Diprifusor) and fentanyl was administered at a dose of 2-3 µg/kg each time analgesia appeared to be inadequate. Hemodynamic measurements as well as bispectral index were monitored and recorded throughout the surgery. Data analysis was performed by using a non-linear mixed-effect population modeling (NONMEM 7.4 software). Three compartment models that incorporated blood flows as parameters were used to describe propofol and fentanyl pharmacokinetics. The delay of the anesthetic effect, with respect to plasma concentrations, was described using a biophase (effect) compartment. The bispectral index was linked to the propofol and fentanyl effect site concentrations through a synergistic Emax model. An empirical linear model was used to describe CO changes observed during the surgery. Cardiac output was identified as an important predictor of propofol and fentanyl pharmacokinetics. Consequently, it affected the depth of anesthesia and the recovery time after propofol-fentanyl TIVA infusion cessation. The model predicted (not observed) CO values correlated best with measured responses. Patients' age was identified as a covariate affecting the rate of CO changes during the anesthesia leading to age-related difference in individual patient's responses to both drugs.

Effect of Blood Loss and Transfusion Requirements on Clinical Outcomes of Fenestrated-Branched Endovascular Aortic Repair

OBJECTIVE

The aim of this study was to evaluate the effect of blood loss and transfusion requirements on clinical outcomes of patients treated by fenestrated-branched endovascular aortic repair (F-BEVAR) for pararenal (PRA) and thoracoabdominal aortic aneurysms (TAAAs).

METHODS

We reviewed the clinical data of 370 consecutive patients (277 male, mean age 74 ± 10 years) treated by F-BEVAR between 2007 and 2017. Outcomes were estimated blood loss (EBL), use of intraoperative blood salvage (IOBS), transfusion of packed red blood cells (PRBCs), mortality, and major adverse events (MAEs).

RESULTS

There were 189 patients (51%) treated for PRAs and 181 patients (49%) treated for TAAAs. IOBS was used in 194 patients (52%) and transfusion of PRBCs was needed in 137 (37%). Thirty-day mortality was 2.2% (8/370) and MAEs occurred in 123 patients (33%), including 74 patients (20%) who had EBL > 1L. EBL > 1L and transfusion of PRBCs were significantly higher (P < 0.05) in patients treated in the first half of clinical experience and in those with larger aneurysms, iliofemoral conduits, bilateral open surgical femoral access and Extent I-III TAAAs. Use of DrySeal^® sheaths (WL Gore, Flagstaff AZ) was associated with significantly lower (P < .05) EBL volume and with less transfusion of PRBCs. On multivariate analysis PRBCs > 1L, male gender and the last half of clinical experience were associated with MAEs/mortality.

CONCLUSIONS

F-BEVAR was associated with significantly higher volume of blood loss and transfusion requirements in patients treated in the early experience and in those who had iliofemoral conduits, open femoral surgical exposure or Extent I-III TAAAs.

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

Importance

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.

Objective

To examine the temporal trends of myocardial infarction (MI) following high-risk vascular procedures.

Design, Setting, and Participants

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.

Exposures

The main exposure was the year of the operation. Other variables of interest included demographics, comorbidities, and other risk factors for MI.

Main Outcomes and Measures

Primary outcome of interest was the incidence of POMI.

Results

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.

Conclusions and Relevance

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.

Neuraxial anaesthesia for lower-limb revascularization

BACKGROUND

Lower-limb revascularization is a surgical procedure that is performed to restore an adequate blood supply to the limbs. Lower-limb revascularization surgery is used to reduce pain and sometimes to improve lower-limb function. Neuraxial anaesthesia is an anaesthetic technique that uses local anaesthetics next to the spinal cord to block nerve function. Neuraxial anaesthesia may lead to improved survival. This systematic review was originally published in 2010 and was first updated in 2011 and again in 2013.

OBJECTIVES

To determine the rates of death and major complications associated with spinal and epidural anaesthesia as compared with other types of anaesthesia for lower-limb revascularization in patients aged 18 years or older who are affected by obstruction of lower-limb vessels.

SEARCH METHODS

The original review was published in 2010 and was based on a search until June 2008. In 2011 we reran the search until February 2011 and updated the review. For this second updated version of the review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, LILACS, CINAHL and Web of Science from 2011 to April 2013.

SELECTION CRITERIA

We included randomized controlled trials comparing neuraxial anaesthesia (spinal or epidural anaesthesia) versus other types of anaesthesia in adults (18 years or older) with arterial vascular obstruction undergoing lower-limb revascularization surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed data extraction and assessed trial quality. We pooled the data on mortality, myocardial infarction, lower-limb amputation and pneumonia. We summarized dichotomous data as odds ratio (OR) with 95% confidence interval (CI) using a random-effects model.

MAIN RESULTS

In this updated version of the review, we found no new studies that met our inclusion criteria. We included in this review four studies that compared neuraxial anaesthesia with general anaesthesia. The total number of participants was 696, of whom 417 were allocated to neuraxial anaesthesia and 279 to general anaesthesia. Participants allocated to neuraxial anaesthesia had a mean age of 67 years, and 59% were men. Participants allocated to general anaesthesia had a mean age of 67 years, and 66% were men. Four studies had an unclear risk of bias. No difference was observed between participants allocated to neuraxial or general anaesthesia in mortality rate (OR 0.89, 95% CI 0.38 to 2.07; 696 participants; four trials), myocardial infarction (OR 1.23, 95% CI 0.56 to 2.70; 696 participants; four trials), and lower-limb amputation (OR 0.84, 95% CI 0.38 to 1.84; 465 participants; three trials). Pneumonia was less common after neuraxial anaesthesia than after general anaesthesia (OR 0.37, 95% CI 0.15 to 0.89; 201 participants; two trials). Evidence was insufficient for cerebral stroke, duration of hospital stay, postoperative cognitive dysfunction, complications in the anaesthetic recovery room and transfusion requirements. No data described nerve dysfunction, postoperative wound infection, patient satisfaction, postoperative pain score, claudication distance and pain at rest.

AUTHORS' CONCLUSIONS

Available evidence from included trials that compared neuraxial anaesthesia with general anaesthesia was insufficient to rule out clinically important differences for most clinical outcomes. Neuraxial anaesthesia may reduce pneumonia. No conclusions can be drawn with regard to mortality, myocardial infarction and rate of lower-limb amputation, or less common outcomes.

Pharmacokinetics and pharmacodynamics of propofol in patients undergoing abdominal aortic surgery

Available propofol pharmacokinetic protocols for target-controlled infusion (TCI) were obtained from healthy individuals. However, the disposition as well as the response to a given drug may be altered in clinical conditions. The aim of the study was to examine population pharmacokinetics (PK) and pharmacodynamics (PD) of propofol during total intravenous anesthesia (propofol/fentanyl) monitored by bispectral index (BIS) in patients scheduled for abdominal aortic surgery. Population nonlinear mixed-effect modeling was done with Nonmem. Data were obtained from ten male patients. The TCI system (Diprifusor) was used to administer propofol. The BIS index served to monitor the depth of anesthesia. The propofol dosing was adjusted to keep BIS level between 40 and 60. A two-compartment model was used to describe propofol PK. The typical values of the central and peripheral volume of distribution, and the metabolic and inter-compartmental clearance were V(C) = 24.7 l, V(T) = 112 l, Cl = 2.64 l/min and Q = 0.989 l/min. Delay of the anesthetic effect, with respect to plasma concentrations, was described by the effect compartment with the rate constant for the distribution to the effector compartment equal to 0.240 min(-1). The BIS index was linked to the effect site concentrations through a sigmoidal E(max) model with EC(50) = 2.19 mg/l. The body weight, age, blood pressure and gender were not identified as statistically significant covariates for all PK/PD parameters. The population PK/PD model was successfully developed to describe the time course and variability of propofol concentration and BIS index in patients undergoing surgery.

Quality of life and mortality assessment in patients with major cardiac events in the postoperative period

BACKGROUND AND OBJECTIVES

Cardiovascular complications in the postoperative period are associated with high mortality and morbidity. Few studies have assessed the degree of dependence in these patients and their perception of health. The objective of this study was to assess the mortality and the quality of life in patients who developed major cardiac events (MCE) in the postoperative period.

METHOD

Retrospective study carried out in a Surgical Intensive Care Unit (SICU), between March 2006 and March 2008. The patients were assessed regarding the occurrence of CE. Six months after the hospital discharge, the Short-Form-36 (SF-36) questionnaire was filled out and dependence was assessed in relation to activities of daily living (ADL). The comparisons between independent groups of patients were carried out using Student's t test. The comparison between each variable and the occurrence of CE was carried out by logistic regression and included all patients.

RESULTS

Of the 1,280 patients that met the inclusion criteria, 26 (2%) developed MCE. The univariate analysis identified as independent determinants for the development of major cardiac events: ASA physical status, hypertension, ischemic heart disease, congestive heart disease and score of the Revised Cardiac Risk Index (RCRI). The six-month mortality after the SICU discharge was 35%. Of the 17 surviving patients, 13 completed the questionnaires. Thirty-one percent of them reported that their general health was better on the day they answered the questionnaire, when compared to 12 months before. Sixty-nine percent of the patients were dependent in instrumental ADL e 15% in personal ADL.

CONCLUSIONS

The development of MCE has a significant impact on the duration of hospital stay and mortality rates. Six months after the discharge from the SICU, more than 50% of the patients were dependent in at least one instrumental ADL.

Neuraxial anaesthesia for lower-limb revascularization

BACKGROUND

Lower-limb revascularization surgery is used to reduce pain and sometimes to improve lower-limb function. The type of anaesthesia used during lower-limb revascularization may affect the risks of both good and bad outcomes.

OBJECTIVES

To determine the rates of death and major complications with spinal and epidural anaesthesia compared with other types of anaesthesia for lower-limb revascularization.

SEARCH STRATEGY

We searched CENTRAL (The Cochrane Library 2008, Issue 2); MEDLINE (1960 to 10th June 2008); EMBASE (1982 to 10th June 2008); LILACS (1982 to 10th June 2008); CINAHL (1982 to 10th June 2008) and ISI Web of Science (1900 to 10th June 2008).

SELECTION CRITERIA

We included randomized controlled trials that evaluated the effect of anaesthetic type in adults aged 18 years or older undergoing lower-limb revascularization surgery.

DATA COLLECTION AND ANALYSIS

Two authors independently performed the data extraction. Primary outcomes were mortality, cerebral stroke, myocardial infarction, nerve dysfunction and postoperative lower-limb amputation rate. The secondary outcome analysed was pneumonia. We judged risk of bias with four criteria: randomization and allocation concealment methods, blinding of treatment and outcome assessment and completeness of follow up. To assess heterogeneity we used the I(2) statistic. We summarized dichotomous data as odds ratio (OR) with 95% confidence interval (CI) using a random-effects model.

MAIN RESULTS

We included four studies that compared neuraxial anaesthesia with general anaesthesia. The total number of participants was 696, of whom 417 were allocated to neuraxial anaesthesia and 279 to general anaesthesia. Participants allocated to neuraxial anaesthesia had a mean age of 67 years and 59% were men. Participants allocated to general anaesthesia had a mean age of 67 years and 66% were men. There was no difference between participants allocated to neuraxial or general anaesthesia in: mortality rate (OR 0.89, 95% CI 0.38 to 2.07; 696 participants, four trials); myocardial infarction (OR 1.23, 95% CI 0.56 to 2.70; 696 participants, four trials); and lower-limb amputation rate (OR 0.84, 95% CI 0.38 to 1.84; 465 participants, three trials). Pneumonia was less common following neuraxial anaesthesia than general anaesthesia (OR 0.37, 95% CI 0.15 to 0.89; 201 participants, two trials).

AUTHORS' CONCLUSIONS

There was insufficient evidence available from the included trials that compared neuraxial anaesthesia with general anaesthesia to rule out clinically important differences for most clinical outcomes. Neuraxial anaesthesia may reduce pneumonia. No conclusions can be drawn with regard to mortality, myocardial infarction and rate of lower-limb amputation or less common outcomes.

Neuroaxis block compared to general anesthesia for revascularization of the lower limbs in the elderly. A systematic review with metanalysis of randomized clinical studies

BACKGROUND AND OBJECTIVES

Currently, it is controversial on whether neuroaxis block (NB) is more effective than general anesthesia (GA) in elderly individuals undergoing non-cardiac surgeries. The objective of this study was to determine the efficiency of NB in comparison to GA for revascularization of the lower limbs (RLL) in the elderly.

METHODS

A search of the following data base was conducted: MEDLINE (1955 to 2007), CINHAL (1982 to 2007), EMBASE (1980 to 2007), LILACS (1982 to 2007), and ISI (1945 to 2007). Two investigators undertook an independent analysis of the studies published to identify randomized clinical trials (RCTs) comparing NB with GA for RLL. The full text of the RCTs that fulfill the inclusion criteria was analyzed. Disagreements were analyzed in consensus meetings. The software Review Manager was used for the Metanalysis by means of odds ratio with a confidence interval of 95%.

RESULTS

Three studies involving 465 patients were selected. Metanalysis of the following parameters did not show statistically significant differences: mortality (OR: 0.90; CI 95%: 0.30-2.73; p = 0.85 for spinal anesthesia; OR: 1.30, CI 95%: 0.38-4.48, p = 0.68, for epidural block); myocardial infarction (OR: 1.38, CI 95%: 0.29-6.46, p = 0.68); and rate of lower limb amputation (OR: 0.81, CI 95%: 0.30-2.19, p = 0.68, for spinal block; OR: 0.70, CI 95%: 0.24-2.07, p = 0.52 for epidural block). A statistically significant difference was observed for pneumonia (OR: 0.37, CI 95%: 0.15-0.89, p = 0.03); however, clinical heterogeneity was present.

CONCLUSIONS

This metanalysis did not generate enough evidence to demonstrate that NB is more efficient, equivalent, or less efficient than GA for RLL in the elderly.

Anesthetic Considerations in the Patient With Valvular Heart Disease Undergoing Noncardiac Surgery

Valvular heart disease can be an important finding in patients presenting for noncardiac surgery. Valvular heart disease and resulting comorbidity, such as heart failure or atrial fibrillation, significantly increase the risk for perioperative adverse events. Appropriate preoperative assessment, adequate perioperative monitoring, and early intervention, should hemodynamic disturbances occur, may help prevent adverse events and improve patient outcome. This review article aims to guide the practitioner in the various aspects of anesthetic management in the perioperative care of patients with valvular heart disease. The pharmacological approach to optimization of patient outcome with drugs, such as βblockers and lipid-lowering medications (statins), is an evolving field, and recent developments are discussed in this article.

Should Cardiac Troponins be Used as a Risk Stratification Tool for Patients with Chronic Critical Limb Ischaemia?

OBJECTIVES

Cardiovascular mortality in patients with chronic critical lower limb ischaemia (CCLI) is high and early risk stratification in these patients may aid clinical management improving outcomes. Cardiac troponin I (cTnI) has prognostic significance in patients with unstable angina. The aim of this study was to evaluate the prognostic significance of cardiac troponins in CCLI patients who had no clinical evidence of unstable coronary heart disease.

METHODS

Patients (n=152) admitted with CCLI to a single vascular unit over a two-year period were included prospectively in this study. Patients with clinical evidence of unstable coronary disease were excluded from the study. Patient demographics, clinical history, co-morbidity and risk factors for peripheral vascular disease were documented. Admission cTnI levels were recorded using a threshold, 0.1 ng/ml. The primary endpoint was mortality.

RESULTS

Fifty-two patients (34.2%) had an elevated cTnI, whilst 100 (65.8%) had cTnI <0.1 ng/ml. Sixty-two patients died during the follow-up period, 38 with an elevated admission cTnI. Death rate in patients with cTnI >0.1 ng/nl was 73% compared with 24% in those with levels below the threshold (p<0.0001). Patients with elevated cTnI were significantly older than those with normal level (median age 76 years vs 71 years, p<0.001). An elevated cTnI was found to independently predict disease-specific mortality on Cox regression analysis (Hazard Ratio 4.2; 95% Confidence Interval 1.3-12.7).

CONCLUSION

In this series of patients with CCLI the measurement of cTnI on admission was a significant independent predictor of survival. cTnI has potential as a prognostic test to stratify patients with a high cardiovascular risk and may enable further optimisation of these high-risk patients.