Perioperative Myocardial Injury after Elective Open Abdominal Aortic Aneurysm Repair Predicts Outcome

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

BACKGROUND

Major vascular surgery is associated with a high perioperative risk and significant mortality. Despite advances in risk stratification, monitoring, and management of perioperative complications, cardiac complications are still common. Stress echocardiography is well established in coronary artery disease diagnostics; however, its prognostic value before high-risk aortic surgery is unknown. This prospective, single-center study compared the outcome of patients undergoing extended cardiac risk assessment before open abdominal aortic surgery with the outcome of patients who had received standard preoperative assessment.

METHODS

The study included patients undergoing elective open abdominal aortic surgery. Patients who underwent standard preoperative assessment before the start of a dedicated protocol were compared with patients who had extended cardiac risk assessment, including dobutamine stress echocardiography, as part of a stepwise interdisciplinary cardiovascular team approach. The combined primary endpoint was cardiovascular death, myocardial infarction, emergency coronary revascularization, and life-threatening arrhythmia within 30 days. The secondary endpoint was acute renal failure and severe bleeding.

RESULTS

In total, 77 patients (mean age 68.1 ± 8.1 years, 70% male) were included: 39 underwent standard and 38 underwent cardiac risk assessment. The combined primary endpoint was reached significantly more often in patients before than after implementation of the extended cardiac stratification procedure (15% vs. 0%, p = 0.025). The combined secondary endpoint did not differ between the groups.

CONCLUSIONS

Patients with extended cardiac risk assessment undergoing elective open abdominal aortic surgery had better 30-day outcomes than did those who had standard preoperative assessment.

Wireless continuous single-lead ST-segment monitoring to detect new-onset myocardial injury at the general ward-An exploratory subanalysis

Patients admitted for acute medical conditions and major noncardiac surgery are at risk of myocardial injury. This is frequently asymptomatic, especially in the context of concomitant pain and analgesics, and detection thus relies on cardiac biomarkers. Continuous single-lead ST-segment monitoring from wireless electrocardiogram (ECG) may enable more timely intervention, but criteria for alerts need to be defined to reduce false alerts. This study aimed to determine optimal ST-deviation thresholds from wireless single-lead ECG for detection of myocardial injury following major abdominal cancer surgery and during acute exacerbation of chronic obstructive pulmonary disease. Patients were monitored with a wireless single-lead ECG patch for up to 4 days and had daily troponin measurements. Single-lead ST-segment deviations of <0.255 mV and/or >0.245 mV (based on previous study comparison with 0.1 mV 12-lead ECG and variation in single-lead ECG) were analyzed for relation to myocardial injury defined as hsTnT elevation of 20-64 ng/L with an absolute change of ≥5 ng/L, or a hsTnT level ≥ 65 ng/L. In total, 528 patients were included for analysis, of which 15.5% had myocardial injury. For corrected ST-thresholds lasting ≥10 and ≥ 20 min, we found specificities of 91% and 94% and sensitivities of 17% and 13% with odds ratios of 2.0 (95% CI: 1.1; 3.9) and 2.4 (95% CI: 1.1; 5.1) for myocardial injury. In conclusion, wireless single-lead ECG monitoring with corrected ST thresholds detected patients developing myocardial injury with specificities >90% and sensitivities <20%, suggesting increased focus on sensitivity improvement.

Myocardial Injury after Non-Cardiac Surgery in Patients Who Underwent Open Repair for Abdominal Aortic Aneurysm: A Retrospective Study

BACKGROUND

Myocardial injury after non-cardiac surgery (MINS) has been known to be associated with mortality in various surgical patients; however, its prognostic role in abdominal aortic aneurysm (AAA) open repair remains underexplored. This study aimed to investigate the role of MINS as a predictor of mortality in patients who underwent AAA open repair.

METHODS

This retrospective study investigated 352 patients who underwent open repair for non-ruptured AAA. The predictors of 30-day and 1-year mortalities were investigated using logistic regression analysis.

RESULTS

MINS was diagnosed in 41% of the patients after AAA open repair in this study. MINS was an independent risk factor of 30-day mortality (odds ratio [OR]: 10.440, 95% confidence interval [CI]: 1.278-85.274, p = 0.029) and 1-year mortality (OR: 5.189, 95% CI: 1.357-19.844, p = 0.016). Kaplan-Meier survival curves demonstrated significantly lower overall survival rates in patients with MINS compared to those without MINS (p = 0.003).

CONCLUSION

This study revealed that MINS is a common complication after AAA open repair and is an independent risk factor of 30-day and 1-year mortalities. Patients with MINS have lower overall survival rates than those without MINS.

Asymptomatic myocardial injury identified on postoperative troponin testing after open or endovascular surgical procedures is a predictor of mortality

OBJECTIVE

Elevated troponin (TnT) levels after open or endovascular surgical procedures have been previously shown to correlate with significantly higher postoperative and short-term mortality. The incidence of asymptomatic myocardial injury after vascular surgical procedures has also been shown to be high. The aim of the present study was to evaluate the utility of routine postoperative TnT screening and long-term outcomes for patients with postoperative TnT elevation.

METHODS

Data from consecutive patients who had undergone open or endovascular surgery on an emergent or elective basis with routine postoperative TnT testing from January 2010 to December 2012 were retrospectively analyzed. Elevated postoperative TnT was considered >0.01 ng/mL. Patients with no documented postoperative TnT levels, those who had denied research authorization, and those with elevated TnT levels secondary to renal insufficiency alone were excluded. Patients were also excluded if they had required a dialysis access procedure, varicose vein procedure, or any procedure performed on an outpatient basis, because these were considered nonmajor surgeries. The end points were all-cause mortality at 30 days and 1, 2, 4, and 8 years postoperatively. Mortality data were retrieved from the electronic medical records and the Social Security Death Index and Accurint Death database.

RESULTS

During the 3-year study period, 1632 patients with postoperative TnT levels available had met the inclusion criteria (70% men; 30% women; mean age, 69.7 years). Postoperatively, 410 patients (25.1%) had had elevated TnT levels (TnT+) and 1222 (74.9%) had had nonelevated TnT levels (TnT-). Of the 410 TnT+ patients, 261 had undergone open, 143 had undergone endovascular, and 6 had undergone hybrid procedures. These included 180 aortic, 128 infrainguinal, 22 cerebrovascular, and 80 upper extremity or miscellaneous procedures. Of the 410 TnT+ patients, 168 had experienced asymptomatic myocardial injury. The 30-day mortality was significantly higher for the TnT+ patients than for the TnT- patients (3.9% vs 0.8%; P < .001). The cumulative probability of death for the TnT+ patients remained significantly higher than that for the TnT- patients at 1 (13% vs 3.2%), 2 (17.8% vs 4.8%), 4 (43% vs 18.5%), and 8 (81.4% vs 48.6%) years (P < .0001). The difference held true even for the 168 asymptomatic TnT+ patients compared with the TnT- patients at 30 days (2.4% vs 0.8%) and 1 (7.6% vs 3.2%), 2 (13.3% vs 4.8%), 4 (43.6 vs 18.5%) and 8 (80.8 vs 48.6%) years (P < .0001).

CONCLUSIONS

In the present study, patients with elevated TnT levels after vascular surgery had had significantly higher early and late all-cause mortality compared with those with normal postoperative TnT levels. This was true even for patients with asymptomatic TnT elevation, suggesting a role might exist for routine postoperative TnT screening to allow for long-term risk stratification and targeted medical management.

Long-term major adverse cardiovascular events following myocardial injury after non-cardiac surgery: meta-analysis

BACKGROUND

Myocardial injury after non-cardiac surgery is diagnosed following asymptomatic troponin elevation in the perioperative interval. Myocardial injury after non-cardiac surgery is associated with high mortality rates and significant rates of major adverse cardiac events within the first 30 days following surgery. However, less is known regarding its impact on mortality and morbidity beyond this time. This systematic review and meta-analysis aimed to establish the rates of long-term morbidity and mortality associated with myocardial injury after non-cardiac surgery.

METHODS

MEDLINE, Embase and Cochrane CENTRAL were searched, and abstracts screened by two reviewers. Observational studies and control arms of trials, reporting mortality and cardiovascular outcomes beyond 30 days in adult patients diagnosed with myocardial injury after non-cardiac surgery, were included. Risk of bias was assessed using the Quality in Prognostic Studies tool. A random-effects model was used for the meta-analysis of outcome subgroups.

RESULTS

Searches identified 40 studies. The meta-analysis of 37 cohort studies found a rate of major adverse cardiac events-associated myocardial injury after non-cardiac surgery of 21 per cent and mortality following myocardial injury after non-cardiac surgery was 25 per cent at 1-year follow-up. A non-linear increase in mortality rate was observed up to 1 year after surgery. Major adverse cardiac event rates were also lower in elective surgery compared with a subgroup including emergency cases. The analysis demonstrated a wide variety of accepted myocardial injury after non-cardiac surgery and major adverse cardiac events diagnostic criteria within the included studies.

CONCLUSION

A diagnosis of myocardial injury after non-cardiac surgery is associated with high rates of poor cardiovascular outcomes up to 1 year after surgery. Work is needed to standardize diagnostic criteria and reporting of myocardial injury after non-cardiac surgery-related outcomes.

REGISTRATION

This review was prospectively registered with PROSPERO in October 2021 (CRD42021283995).

[Diagnosis and Management of Perioperative Myocardial Ischemia after Elective Aortic Aneurysm Surgery]

INTRODUCTION

Perioperative myocardial ischemia (PMI) is a serious postoperative complication. Aortic operations represent an especially high-risk surgery concerning cardiac complications. This aim of this study was to analyse the clinical features of PMI after elective aortic aneurysm surgery.

PATIENTS AND METHODS

This study is a retrospective analysis of 863 patients who underwent elective aortic aneurysm surgery between 2005 and 2012 in the Department of Vascular and Endovascular Surgery of Heidelberg University Hospital with regard to PMI. The PMI diagnosis was based on a positive serum troponin diagnostic test. We evaluated the clinical course, time point of the diagnosis and features of diagnostics to characterise PMI. Moreover, we analysed the treatment options and management of the patients' discharge.

RESULTS

Thirty-one patients (3.6% of 863) with PMI after elective aortic aneurysm surgery were identified. Of these, 21 patients (67.7%) underwent open surgery and 10 patients (32.3%) received endovascular treatment. PMI was diagnosed in 24 patients (77%) during the first 3 days. More than half of these patients (16/31) were clinically asymptomatic. Electrocardiogram did not show pathological findings in 24 cases (77.4%). The first troponin measurement was not elevated in eight patients (25.8%). Drug therapy alone was used in 17 cases (54.8%) of PMI, coronary catheterisation was performed in 12 patients (38.7%) and two patients (6.5%) received aortocoronary bypass. Fourteen patients (45.1%) were discharged home and another 14 patients (44.1%) were transferred to another hospital or to a rehabilitation institution. Two patients died because of multi-organ failure.

CONCLUSION

PMI is not a rare complication after elective aortic surgery. The diagnosis of PMI can be challenging because of occult symptoms especially in a perioperative setting. Due to the potentially serious consequences, cardiac enzyme diagnostics should be initiated immediately if there is suspicion of PMI or routinely in defined at-risk patients after aortic surgery.

Cost-effectiveness of a population-based AAA screening program for men over 65 years old in Iran

BACKGROUND

Screening program tend to recognized patients in their early stage and consequently improve health outcomes. Cost-effectiveness of the abdominal aortic aneurysm (AAA) screening program has been scarcely studied in developing countries. We sought to evaluate the cost-effectiveness of a screening program for the abdominal aortic aneurysm (AAA) in men aged over 65 years in Iran.

METHODS

A Markov cohort model with 11 mutually exclusive health statuses was used to evaluate the cost-effectiveness of a population-based AAA screening program compared with a no-screening strategy. Transitions between the health statuses were simulated by using 3-month cycles. Data for disease transition probabilities and quality of life outcomes were obtained from published literature, and costs were calculated based on the price of medical services in Iran and the examination of the patients' medical records. The outcomes were life-years gained, the quality-adjusted life-year (QALY), costs, and the incremental cost-effectiveness ratio (ICER). The analysis was conducted for a lifetime horizon from the payer's perspective. Costs and effects were discounted at an annual rate of 3%. Uncertainty surrounding the model inputs was tested with deterministic and probabilistic sensitivity analyses.

RESULTS

The mean incremental cost of the AAA screening strategy compared with the no-screening strategy was $140 and the mean incremental QALY gain was 0.025 QALY, resulting in an ICER of $5566 ($14,656 PPP) per QALY gained. At a willingness-to-pay of 1 gross domestic product (GDP) per capita ($5628) per QALY gained, the probability of the cost-effectiveness of AAA screening was about 50%. However, at a willingness-to-pay of twice the GDP per capita per QALY gained, there was about a 95% probability for the AAA screening program to be cost-effective in Iran.

CONCLUSIONS

The results of this study showed that at a willingness-to-pay of 1 GDP per capita per QALY gained, a 1-time AAA screening program for men aged over 65 years could not be cost-effective. Nevertheless, at a willingness-to-pay of twice the GDP per capita per QALY gained, the AAA screening program could be cost-effective in Iran. Further, AAA screening in high-risk groups could be cost-effective at a willingness-to-pay of 1 GDP per capita per QALY gained.

Risk factors and outcomes of myocardial injury after non-cardiac surgery in high-risk patients who underwent radical cystectomy

Radical cystectomy is considered the standard treatment for patients with muscle-invasive bladder tumors and has high postoperative complication rates among urological surgeries. High-risk patients, defined as those ≥45 years of age with history of coronary artery disease, stroke, or peripheral artery disease or those ≥65 years of age, can have a higher incidence of cardiac complications. Therefore, we evaluated the incidence, risk factors, and outcomes of myocardial injury after non-cardiac surgery (MINS) in high-risk patients who underwent radical cystectomy.This retrospective observational study analyzed 248 high-risk patients who underwent radical cystectomy. MINS was defined as serum troponin I concentration ≥0.04 mg/L within postoperative 3 days. The risk factors for MINS were evaluated by multivariate logistic regression analysis. Postoperative outcomes were evaluated. The 1-year survival after radical cystectomy was also compared between patients who developed MINS (MINS group) and those who did not (non-MINS group) by Kaplan-Meier analysis.MINS occurred in 35 patients (14.1%). Multivariate logistic regression analysis showed that early diastolic transmitral filling velocity (E)/early diastolic septal mitral annular velocity (E') ratio (odds ratio = 1.102, 95% confidence interval [1.009-1.203], P = .031) and large volume blood transfusion (odds ratio = 2.745, 95% confidence interval [1.131-6.664], P = .026) were significantly associated with MINS in high-risk patients who underwent radical cystectomy. Major adverse cardiac events and 1-year mortality were significantly higher in the MINS group than in the non-MINS group (17.1% vs 6.1%, P = .035; 28.6% vs 12.7%, P = .021, respectively). Kaplan-Meier analysis showed significantly lower 1-year survival in the MINS group than in the non-MINS group (P = .010).MINS occurred in 14.1% of patients. High E/E' ratio and large volume blood transfusion were risk factors for MINS in high-risk patients who underwent radical cystectomy. Postoperative major adverse cardiac events and 1-year mortality were significantly higher in the MINS group than in the non-MINS group. Preoperative evaluation of risk factors for MINS may provide useful information to detect cardiovascular complications after radical cystectomy in high-risk patients.

C, Kumar L, Pillai A. Myocardial injury after noncardiac surgery-incidence and predictors from a prospective observational cohort study at an Indian tertiary care centre

Asymptomatic myocardial injury following noncardiac surgery (MINS) is an independent predictor of 30-day mortality and may go unrecognized based on standard diagnostic definition for myocardial infarction (MI). Given lack of published research on MINS in India, our study aims to determine incidence of MINS in patients undergoing noncardiac surgery at our tertiary care hospital, and evaluate the clinical characteristics including 30-day outcome.The prospective observational study included patients >65 years or >45 years with either hypertension (HTN), diabetes mellitus (DM), coronary artery disease (CAD), cerebrovascular accident (CVA), or peripheral arterial disease undergoing noncardiac surgery. MINS was peak troponin level of ≥0.03 ng/dL at 12-hour or 24-hour postoperative. All patients were followed for 30 days postoperatively. Predictors of MINS and mortality were analyzed using multivariate logistic regression. Patients categorized based on peak troponin cut-off values determined by receiver operating characteristic curve were analyzed by Kaplan-Meir test to compare the survival of patients between the groups.Among 1075 patients screened during 34-month period, the incidence of MINS was 17.5% (188/1075). Patients with DM, CAD, or who underwent peripheral nerve block anaesthesia were 1.5 (P < .01), 2 (P < .001), and 12 (P < .001) times, respectively, more likely to develop MINS than others. Patients with heart rates ≥96 bpm before induction of anesthesia were significantly associated with MINS (P = .005) and mortality (P = .02). The 30-day mortality in MINS cohort was 11.7% (22/188, 95% CI 7.5%-17.2%) vs 2.5% (23/887, 95% CI 1.7%-3.9%) in patients without MINS (P < .001). ECG changes (P = .002), peak troponin values >1 ng/mL (P = .01) were significantly associated with mortality. A peak troponin cut-off of >0.152 ng/mL predicted mortality among MINS patients at 72% sensitivity and 58% specificity. Lack of antithrombotic therapy following MINS was independent predictor of mortality (P < .001), with decreased mortality in patients who took post-op ASA (Aspirin) or Clopidogrel. Mortality among MINS patients with post-op ASA intake is 6.7% vs 12.1% among MINS patients without post-op ASA intake. Mortality among MINS patients with post-op Clopidogrel intake is 10.5% vs 11.8% among MINS patients without post-op Clopidogrel intake.A higher (17.5%, 95% CI 15-19%) incidence of MINS was observed in our patient cohort with significant association with 30-day mortality. Serial postoperative monitoring of troponin following noncardiac surgery as standard of care, would identify "at risk" patients translating to improved outcomes.

Randomized comparison of sevoflurane versus propofol-remifentanil on the cardioprotective effects in elderly patients with coronary heart disease

Background

It is skeptical about cardioprotective property of sevoflurane in patients undergoing noncardiac surgery, especially in the elderly patients with coronary heart disease. We hypothesized that long duration of sevoflurane inhalation in noncardiac surgery could ameliorate myocardial damage in such patients.

Methods

This was a randomized, prospective study. One hundred twenty-one elderly patients with coronary heart disease were randomly allocated into two groups. Maintenance of anesthesia was achieved by sevoflurane inhalation (Group S) or propofol-remifentanil respectively (Group PR). Serum cardiac troponin I (cTnI) and brain natriuretic peptide (BNP) were measured before anesthesia induction (T0), 8 h (T1) and 24 h (T2) after anesthesia respectively. The perioperative cardiac output, complications and postoperative 3-month follow-up from end of surgery were recorded.

Results

Between the two groups, there were no statistical differences in the values of cTnI and BNP during the study. However, The area under the curve of cTnI values over 24 h after operation was less in Group S. Group PR had lower cardiac output and consumed more amount of phenylephrine during the study (P < 0.05).

Conclusions

Compared with the group PR, sevoflurane had no benefit in the myocardial protection for the elderly patients with CHD. However, Sevoflurane showed advantage in maintaining hemodynamic stability during the operative period.

Trial registration

Chinese Clinical Trial Registry, ChiCTR-IPR-16008871, 21 July 2016.

An update on predictive biomarkers for major adverse cardiovascular events in patients undergoing vascular surgery

Cardiovascular complications signify a major cause of morbidity and mortality in patients undergoing vascular surgery adversely affecting both short- and long-term prognosis. During the last decade, unmet needs for a distinct cardiovascular risk assessment have led to an intensive research for establishment of biomarkers with sufficient predictive value. This literature review aims in examining the value of several biomarkers in predicting the incidence of major adverse cardiac events in vascular surgery patients. We reviewed the English language literature and analyzed the biomarkers as independent predictors or in correlation with other factors. We found several biomarkers showing a significant predictive value for a major adverse cardiovascular event in patients undergoing vascular surgery. These biomarkers can be used in clinical practice as outcome predictors, although sensitivity and specificity varies. Detection of subclinical cardiovascular damage may improve total risk estimation and facilitate clinical assessment of patients at risk for future cardiovascular events. The wide variety of sensitivity and specificity in predicting a MACE of these biomarkers exert the need for future trials in which these markers will be tested as adjunctive tools of cardiovascular risk estimation scoring systems.

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

Introduction:

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.

Methods:

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.

Results:

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.

Conclusions:

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.

Hypoxia-induced inflammation and purinergic signaling in cross clamping the human aorta

Open aortic surgery evokes a systemic inflammatory response and is associated with high morbidity and mortality. Purinergic signaling has been shown to be crucial for maintaining vascular integrity and attenuating inflammation related to hypoxia. The involvement of purinergic signaling in cross clamping of major human arteries is unknown. Our aim was to compare systemic inflammatory responses and hypoxia-induced purinergic signaling in patients undergoing either open infra-renal abdominal aortic repair or infra-inguinal revascularization. Pre- and 24 h post-operative blood samples were gathered from 6 patients undergoing aortic clamping and 6 similar patients undergoing common femoral artery cross-clamping. Using Biorad Multipex™ 21- and 27-panels 48 different cytokines, chemokines and growth factors were analyzed, in addition to circulating levels of ATP, ADP, CD39, CD73 and HIF-1α, and compared between the groups. Several inflammatory cytokines were elevated from baseline levels after aortic clamping, but not after femoral cross clamping. Most pronoun rises were seen in IL-6 (667 %, P = 0.016) and HGF (760 %, P = 0.016). HIF-1α values showed a steady increase after clamping of either artery unless the subject underwent blood transfusion. Despite an adequate increase in HIF-1α CD39 and CD73 activity decreased significantly after aortic clamping (P = 0.047 and P = 0.016, respectively). Aortic clamping is associated with a clear and strong systemic inflammatory response and impaired repair mechanisms in terms of purinergic signaling. Patients undergoing open aorta repair could benefit from pre-operative medical therapy, which enhances CD73 expression.

Myocardial injury after noncardiac surgery

PURPOSE OF REVIEW

Recent investigations have substantially improved our understanding of myocardial injury after noncardiac surgery (MINS).

RECENT FINDINGS

MINS is defined as a prognostically relevant myocardial injury due to ischemia that occurs during or within 30 days after noncardiac surgery. MINS occurs in 8% of adults undergoing major noncardiac surgery and is diagnosed with an elevated postoperative troponin measurement. MINS is associated with significant morbidity, and approximately 10% of patients experiencing MINS will die within 30 days. There is a dose-graded response in mortality and time to death with increasing levels of postoperative troponin elevations. Most patients (>80%) suffering from MINS will not experience an ischemic symptom. Without troponin monitoring, the majority of MINS events would go undetected. To avoid missing these prognostically relevant events, guidelines now recommend perioperative troponin monitoring in high-risk patients having noncardiac surgery. In patients who suffer MINS, risk-adjusted observational data suggest that aspirin and a statin can reduce the risk of 30-day mortality.

SUMMARY

Among adults, MINS is the most common cardiovascular complication that occurs after noncardiac surgery. Given that worldwide 200 million adult patients undergo major noncardiac surgery each year, at least 8 million of these patients will suffer MINS making this a substantial public health problem.

Myocardial injury after surgery is a risk factor for weaning failure from mechanical ventilation in critical patients undergoing major abdominal surgery

Background

Myocardial injury after noncardiac surgery (MINS) is a newly proposed concept that is common among adults undergoing noncardiac surgery and associated with substantial mortality. We analyzed whether MINS was a risk factor for weaning failure in critical patients who underwent major abdominal surgery.

Methods

This retrospective study was conducted in the Department of Critical Care Medicine of Peking University People's Hospital. The subjects were all critically ill patients who underwent major abdominal surgery between January 2011 and December 2013. Clinical and laboratory parameters during the perioperative period were investigated. Backward stepwise regression analysis was performed to evaluate MINS relative to the rate of weaning failure. Age, hypertension, chronic renal disease, left ventricular ejection fraction before surgery, Acute Physiologic and Chronic Health Evaluation II score, pleural effusion, pneumonia, acute kidney injury, duration of mechanical ventilation before weaning and the level of albumin after surgery were treated as independent variables.

Results

This study included 381 patients, of whom 274 were successfully weaned. MINS was observed in 42.0% of the patients. The MINS incidence was significantly higher in patients who failed to be weaned compared to patients who were successfully weaned (56.1% versus 36.5%; P<0.001). Independent predictive factors of weaning failure were MINS, age, lower left ventricular ejection fraction before surgery and lower serum albumin level after surgery. The MINS odds ratio was 4.098 (95% confidence interval, 1.07 to 15.6; P = 0.04). The patients who were successfully weaned had shorter hospital stay lengths and a higher survival rate than those who failed to be weaned.

Conclusion

MINS is a risk factor for weaning failure from mechanical ventilation in critical patients who have undergone major abdominal surgery, independent of age, lower left ventricular ejection fraction before surgery and lower serum albumin levels after surgery.

Electrophysiological, hemodynamic, and metabolic response to open procedure or endovascular repair of infrarenal aortic aneurysms

BACKGROUND

The occurrence of cardiovascular diseases in the group of patients undergoing vascular surgery because of abdominal aorta aneurysm is very high. Endovascular procedures are regarded as hemodynamically safer for the patients. The aim of this study was to compare the changes in electrophysiological, hemodynamic, and metabolic parameters depending on the type of operation, using invasive hemodynamic monitoring and Holter electrocardiography recording.

METHODS

A prospective, observational, nonrandomized study was conducted to compare dynamic changes of electrophysiological parameters (dominant rhythm, arrhythmia, corrected QT interval (QTc), invasive blood pressure, electrolytes, and acid-base balance in defined points during perioperative time in 2 groups: vascular prosthesis implantation group (91 patients) and stent-graft implantation group (83 patients).

RESULTS

The study group comprised 174 consecutive adult Caucasian patients (mean age 64.4 ± 8.9 years in stent-graft group and 70.0 ± 7.5 years in vascular prosthesis implantation group). Although patients in the stent-graft implantation group were younger, they were diagnosed with lower limbs vascular atherosclerosis, type 2 diabetes mellitus, and a lower left ventricle ejection fraction more often than patients in the open procedure group. During the open procedure, higher blood pressure amplitudes (P = 0.00009), higher decrease in pH (P = 0.049), increase in the arterial lactate level (P = 0.00002), prolonged QTc values (P = 0.001), more frequent ventricular extrasystoles (P = 0.005), and cardiovascular deaths were observed, when compared with those observed during the endovascular aneurysm repair.

CONCLUSIONS

When compared with the chosen techniques, the one for infrarenal abdominal aneurysm was found to be associated with significant differences in electrophysiological, hemodynamic, and metabolic parameters.

Myocardial injury after noncardiac surgery: a large, international, prospective cohort study establishing diagnostic criteria, characteristics, predictors, and 30-day outcomes

BACKGROUND

Myocardial injury after noncardiac surgery (MINS) was defined as prognostically relevant myocardial injury due to ischemia that occurs during or within 30 days after noncardiac surgery. The study's four objectives were to determine the diagnostic criteria, characteristics, predictors, and 30-day outcomes of MINS.

METHODS

In this international, prospective cohort study of 15,065 patients aged 45 yr or older who underwent in-patient noncardiac surgery, troponin T was measured during the first 3 postoperative days. Patients with a troponin T level of 0.04 ng/ml or greater (elevated "abnormal" laboratory threshold) were assessed for ischemic features (i.e., ischemic symptoms and electrocardiography findings). Patients adjudicated as having a nonischemic troponin elevation (e.g., sepsis) were excluded. To establish diagnostic criteria for MINS, the authors used Cox regression analyses in which the dependent variable was 30-day mortality (260 deaths) and independent variables included preoperative variables, perioperative complications, and potential MINS diagnostic criteria.

RESULTS

An elevated troponin after noncardiac surgery, irrespective of the presence of an ischemic feature, independently predicted 30-day mortality. Therefore, the authors' diagnostic criterion for MINS was a peak troponin T level of 0.03 ng/ml or greater judged due to myocardial ischemia. MINS was an independent predictor of 30-day mortality (adjusted hazard ratio, 3.87; 95% CI, 2.96-5.08) and had the highest population-attributable risk (34.0%, 95% CI, 26.6-41.5) of the perioperative complications. Twelve hundred patients (8.0%) suffered MINS, and 58.2% of these patients would not have fulfilled the universal definition of myocardial infarction. Only 15.8% of patients with MINS experienced an ischemic symptom.

CONCLUSION

Among adults undergoing noncardiac surgery, MINS is common and associated with substantial mortality.

Exercise-induced cardioprotection is mediated by a bloodborne, transferable factor

Exercise protects against myocardial ischemia-reperfusion (I-R) injury but the mechanism remains unclear. Protection can be transferred from a remotely preconditioned human donor to an isolated perfused rabbit heart using a dialysate of plasma. We hypothesized that physical exercise preconditioning also confers cardioprotection through a humorally mediated effector dependent on opioid receptor activation. Thirteen male volunteers performed vigorous exercise (four 2-minute bouts of high-intensity exercise) and 1 week later they underwent remote ischemic preconditioning (four cycles of 5 min upper limb ischemia and reperfusion). Dialysates were prepared from blood collected before (control) and after the two interventions. Isolated rabbit hearts were perfused with the dialysates without and with co-administration of naloxone (opioid receptor antagonist) prior to 40 min regional ischemia and 2 h reperfusion. Exercise and remote ischemic preconditioning (rIPC) reduced infarct size from 60 ± 5 to 35 ± 5 % and from 57 ± 7 to 27 ± 3 % of the area at risk, respectively (p < 0.05 and < 0.01). Furthermore, post-ischemic left ventricular developed pressure was improved compared with controls (p = 0.08 for exercise and p = 0.04 for rIPC). Co-perfusion with naloxone abrogated the protective effects of exercise and remote ischemic preconditioned dialysates. In conclusion, high-intensity exercise preconditioning elicits cardioprotection through a humorally mediated dependent on opioid receptor activation, similar to rIPC.

Volatile agents for cardiac protection in noncardiac surgery: a randomized controlled study

OBJECTIVE

Volatile anesthetics reduce the risk of myocardial infarction and mortality in coronary artery surgery. Recently, the American College of Cardiology/American Heart Association Guidelines suggested the use of volatile anesthetic agents for the maintenance of general anesthesia during noncardiac surgery in patients at risk for perioperative myocardial ischemia, but no randomized experience to document the cardioprotective effects of these agents exists in this setting. Therefore, the authors performed a prospective, randomized, controlled trial to compare the effects of sevoflurane versus total intravenous anesthesia, in terms of postoperative cardiac troponin I release in patients undergoing noncardiac surgery.

DESIGN

A randomized, controlled trial.

SETTING

A teaching hospital.

PARTICIPANTS

Eighty-eight consecutive patients undergoing noncardiac surgery.

INTERVENTIONS

Patients were allocated randomly to receive either volatile anesthetic (44 patients) as the main anesthetic agent or total intravenous anesthesia (TIVA) (44 patients).

MEASUREMENTS

Postoperative cardiac troponin I release was measured as a marker of myocardial necrosis. Patients with detectable postoperative troponin I in the sevoflurane group (12/44, 27.3%) were similar to those in the propofol group (9/44, 20.5%; p = 0.6). There was no significant reduction of postoperative median peak cTnI release (0.16 ± 0.71 ng/mL in the sevoflurane group compared with the TIVA group, 0.03 ± 0.08 ng/mL; p = 0.4). Three patients died at the 1-year follow-up for noncardiac causes (2 in the TIVA group).

CONCLUSIONS

In the authors' experience, patients undergoing noncardiac surgery did not benefit from anesthesia based on halogenated anesthetics. Further studies are necessary to evaluate the cardioprotective effects of volatile agents in noncardiac surgery.

Anesthesia for Open Abdominal Aortic Aneurysm Repair

Abdominal aortic aneurysms (AAAs) are the 13th leading cause of death in the United States 1 and approximately 40,000 patients undergo elective AAA repair each year.2 With the population aging, this number is expected to increase. Although the use of endovascular AAA repair is becoming more common, open repair, first reported by Dubost et al. in 1951 remains the gold standard.2 This chapter will review the etiology, risk factors, diagnosis, pathophysiology, operative technique, perioperative management, and postoperative complications of patients undergoing open AAA repair.

Perioperative cardiac damage in vascular surgery patients

BACKGROUND

Patients undergoing vascular surgery are at increased risk for developing cardiac complications. Majority of patients with perioperative myocardial damage are asymptomatic. Our objective is to review the available literature addressing the prevalence and prognostic implications of perioperative myocardial damage in vascular surgery patients.

METHODS

An Internet-based literature search was performed using MEDLINE to identify all published reports on perioperative myocardial damage in vascular surgery patients. Only those studies published from 2000 to 2010 evaluating myocardial damage using troponin I or T, with or without symptoms of angina pectoris were included.

RESULTS

Thirteen studies evaluating the prevalence of perioperative myocardial ischaemia or infarction were included in the study. The incidence of perioperative myocardial ischaemia ranged from 14% to 47% and the incidence of perioperative myocardial infarction ranged from 1% to 26%. In addition, 10 studies evaluating the prognostic value of perioperative myocardial ischaemia towards postoperative mortality or the occurrence of major adverse cardiac events were included. In the retrieved studies, hazard ratios varied from 1.9 to 9.0.

CONCLUSION

The high prevalence and asymptomatic nature of perioperative myocardial damage, combined with a substantial influence on postoperative mortality of vascular surgery patients, underline the importance of early detection and adequate management of perioperative myocardial damage. This article provides an extended overview regarding the prevalence and prognostic value of perioperative myocardial ischaemia and infarction in vascular surgery patients. In addition, treatment options to reduce the risk of perioperative myocardial damage are provided based on the current available literature.