Perioperative myocardial infarction—aetiology and prevention

The Evolution of Current Management for Carotid Artery Bifurcation Disease

Options for treatment of symptomatic carotid bifurcation disease include carotid endarterectomy (CEA) and carotid artery stenting (CAS). While over the years CEA has established itself as the gold standard for carotid artery revascularization, results from recent trials have shown CAS to be safe and effective in selected patients. This review details the evolution of carotid artery bifurcation disease by highlighting key clinical trials.

Preoperative Assessment of Patients with Vascular Disease

Patients with vascular disease represent a particularly high-risk surgical population. Many of the comorbidities that contribute to their vascular presentation impact a number of vascular beds or other organ systems. As a result, these patients have the highest rates of cardiac and pulmonary complications among patients with noncardiac surgery. The vascular surgeon is in a unique position to help evaluate and treat many of these conditions to not only reduce the perioperative risk but also to improve the patient's overall health. This article presents a comprehensive review of the common preoperative evaluations that have a high impact on patients with vascular disease.

The Effect of Modifiable Risk Factors on Postoperative Complications in Lumbar Spine Fusions

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The impact of modifiable risk factors (MRFs) on complications, costs, and readmission rates at 30, 90, and 180-days following lumbar spine fusion.

METHODS

Patients with lumbar spine fusions within the 2016-2017 Nationwide Readmissions Database (NRD). Patients were stratified by the following MRFs: Alcohol use, tobacco/nicotine use, nutritional malnourishment, dyslipidemia, and primary hypertension. Differences in complications, non-elective readmission rates, costs, and length of stay were compared between MRFs and the non-MRF group. Statistical analysis was conducted using Tukey multiple comparisons of means, 1-way ANOVA, Wald testing, unpaired Welch 2-sample t-tests, multivariate analysis, and predictive modeling.

RESULTS

The final analysis included 297,579 lumbar fusion patients. At 30 and 90 days, patients with nutritional malnutrition, dyslipidemia, and primary hypertension had significantly greater readmission rates than patients without MRFs (all P<0.01). At 180-days, all MRFs had significantly greater readmission rates than the non-MRF group (all P<0.001). Dyslipidemia demonstrated significantly greater rates of myocardial infarction at 90 days compared to all groups (all P<0.02). Nutritional malnutrition was associated with a significantly greater mortality rate than primary hypertension, non-MRF, and tobacco/nicotine use at 90 days (P<0.001) and only tobacco/nicotine use at 180 days (P=0.007). Predictive modeling showed increases of 0.77%, 1.70%, and 2.44% risk of readmission at 30, 90, and 180-days respectively per additional MRF (all P<0.001).

CONCLUSIONS

These findings highlight the negative impact each MRF has on patients following lumbar spinal fusion. Further longitudinal research is necessary to comprehensively characterize the effects of various MRFs on spine surgery outcomes.

Risk of myocardial infarction after invasive outpatient procedures

OBJECTIVE

To assess the short-term risk of acute myocardial infarction (AMI) associated with procedures performed at outpatient specialised hospital clinics.

METHODS

In this case-crossover, population-based study, we identified first-time AMI cases aged ≥40 years via patient registries and linked them to their surgical intervention in Norway (2008-2016) and Sweden (2001-2014), respectively. The number of individuals with AMI who underwent procedures 0-7 days (hazard period) prior to the AMI diagnosis was compared with cases who were exposed 29-36 days (control period) before the AMI. A total of 6176 patients with AMI who underwent a procedure either during the defined hazard or control period contributed to the analyses. ORs with 95% CIs were computed using conditional logistic regression.

RESULTS

The mean age of the total population was 74.7 years and 64.6% were male. The relative risk was higher following procedures performed under general/regional anaesthesia for gastrointestinal endoscopy (OR_summary, 4.23, 95% CI 1.58 to 11.31), vascular (OR_summary, 3.12, 95% CI 1.10 to 8.90), urological/gynaecological (OR_summary, 2.30, 95% CI 1.50 to 3.53) and orthopaedic (OR_summary,1.78, 95% CI 1.30 to 2.44) procedures, and for ENT (ear, nose and throat) and mouth procedures (OR_summary, 1.53, 95% CI 1.19 to 1.99) performed under local anaesthesia.

CONCLUSION

This large population-based register study from two countries suggests that outpatient procedures are generally safe with regard to the postoperative risk of AMI. However, some procedures, such as gastrointestinal endoscopy, vascular procedures and urological/gynaecological procedures may increase the risk of AMI by twofold or threefold within the first 8 days after the procedures. Further studies are warranted to assess whether the effect is modified by cardiovascular medication or other clinical factors.

Evaluation of the cardiovascular risk in patients undergoing major non-cardiac surgery: role of cardiac-specific biomarkers

Major adverse cardiovascular events are frequently observed in patients undergoing major non-cardiac surgery during the peri-operative period. At this time, the possibility to predict cardiovascular events remains limited, despite the introduction of several algorithms to calculate the risk of adverse events, mainly death and major adverse cardiovascular events (MACE) based on the clinical history, risk factors (sex, age, lipid profile, serum creatinine) and non-invasive cardiac exams (electrocardiogram, echocardiogram, stress tests). The cardiac-specific biomarkers natriuretic peptides (NPs) and cardiac troponins (cTn) have been proposed as additional tools for risk prediction in the peri-operative period, particularly for the identification of myocardial injury in patients undergoing major non-cardiac surgery. The prognostic information from the measurement of BNP/NT-proBNP and hs-cTn is independent and complementary to other important indicators of risk, also including ECG and imaging techniques. Elevated levels of cardiac-specific biomarkers before surgery are associated with a markedly higher risk of MACE during the peri-operative period. BNP/NT-proBNP and hs-cTn should be measured in all patients during the clinical evaluation before surgery, particularly during intermediate- or high-risk surgery, in patients aged >65 years and/or with comorbidities. Several questions remain to be assessed in dedicated clinical studies, such as how to optimize the management of patients with raised cardiac specific biomarkers before surgery, and whether a strategy based on biomarker measurement improves patient outcomes and is cost-effective.

Risk for Acute Myocardial Infarction After Ophthalmologic Procedures

BACKGROUND

Preoperative cardiovascular evaluations are frequently done before ambulatory ophthalmologic procedures. However, whether these procedures can trigger an acute myocardial infarction (AMI) is unknown.

OBJECTIVE

To assess the short-term risk for AMI associated with ophthalmologic procedures.

DESIGN

Case-crossover design.

SETTING

Population-based nationwide study from Norway and Sweden.

PARTICIPANTS

First-time patients with AMI, aged 40 years and older, identified via inpatient registries and linked to outpatient surgical procedures in Norway (2008 to 2014) and Sweden (2001 to 2014), respectively.

MEASUREMENTS

Using self-matching, for each participant, exposure to ophthalmologic procedures in the 0 to 7 days before AMI diagnosis (hazard period) was compared with an 8-day period 30 days earlier, that is, days 29 to 36 before AMI (control period) to estimate the relative risk for an AMI the week after an ophthalmologic procedure. The odds ratios (ORs) with 95% CIs were calculated, using conditional logistic regression. Only patients who had a procedure of interest during either the hazard or control period were included.

RESULTS

For the 806 patients with AMI included in this study, there was a lower likelihood of AMI in the week after an ophthalmologic procedure than during the control week (OR_, 0.83; 95% CI, 0.75 to 0.91). Furthermore, there was no evidence of increased risk for AMI when analyses were stratified by surgery subtype, anesthesia (local or general), duration, invasiveness (low, intermediate, or high), patient's age (<65 years or ≥65 years), or comorbidity (none vs. any).

LIMITATION

Potential bias from time-varying confounders between the hazard and the control periods.

CONCLUSION

Ophthalmologic procedures done in an outpatient setting did not seem to be associated with an increased risk for AMI.

PRIMARY FUNDING SOURCE

Central Norway Regional Health Authority and the Swedish Research Council.

Natriuretic Peptides and Troponins to Predict Cardiovascular Events in Patients Undergoing Major Non-Cardiac Surgery

Patients undergoing major surgery have a substantial risk of cardiovascular events during the perioperative period. Despite the introduction of several risk scores based on medical history, classical risk factors and non-invasive cardiac tests, the possibility of predicting cardiovascular events in patients undergoing non-cardiac surgery remains limited. The cardiac-specific biomarkers, natriuretic peptides (NPs) and cardiac troponins (cTn) have been proposed as additional tools for risk prediction in the perioperative period. This review paper aims to discuss the value of preoperative levels and perioperative changes in cardiac-specific biomarkers to predict adverse outcomes in patients undergoing major non-cardiac surgery. Based on several prospective observational studies and six meta-analyses, some guidelines recommended the measurement of NPs to refine perioperative cardiac risk estimation in patients undergoing non-cardiac surgery. More recently, several studies reported a higher mortality in surgical patients presenting an elevation in high-sensitivity cardiac troponin T and I, especially in elderly patients or those with comorbidities. This evidence should be considered in future international guidelines on the evaluation of perioperative risk in patients undergoing major non-cardiac surgery.

CircTRRAP Knockdown Has Cardioprotective Function in Cardiomyocytes via the Signal Regulation of miR-370-3p/PAWR Axis

Background

Circular RNA Transformation/Transcription Domain Associated Protein (circTRRAP, hsa_circ_0081241) was abnormally upregulated in acute myocardial infarction (AMI) patients. However, its biological role and functional mechanism in AMI remain to be researched.

Methods

Human cardiomyocyte AC16 was exposed to hypoxia to induce cell injury. Cell viability was detected through Cell Counting Kit-8. CircTRRAP, microRNA-370-3p (miR-370-3p), and Pro-Apoptotic WT1 Regulator (PAWR) levels were assayed by reverse transcription-quantitative polymerase chain reaction. Cell proliferation analysis was performed via 5-ethynyl-2′-deoxyuridine (EdU) assay. Cell apoptosis was assessed using flow cytometry and caspase-3 activity assay. The protein levels were measured through western blot. Enzyme-linked immunosorbent assay was used to examine the release of inflammatory cytokines. Oxidative stress was assessed by the commercial kits. Dual-luciferase reporter assay, RNA immunoprecipitation, and RNA pull-down assays were performed for the validation of target interaction.

Results

CircTRRAP was highly expressed following hypoxia treatment in AC16 cells. Downregulation of circTRRAP promoted cell growth but inhibited apoptosis, inflammation, and oxidative stress in hypoxic cells. CircTRRAP could target miR-370-3p, and the regulatory effects of circTRRAP on the hypoxic cells were associated with the sponge function of miR-370-3p. PAWR served as the target for miR-370-3p, and it was regulated by circTRRAP/miR-370-3p axis. The protective role of miR-370-3p was achieved by downregulating the PAWR expression in hypoxia-treated AC16 cells.

Conclusion

These findings demonstrated that silence of circTRRAP exerted the protection against the hypoxia-induced damages in cardiomyocytes through regulating the miR-370-3p and PAWR levels.

Cardiopulmonary Exercise Testing and Other Tests of Functional Capacity

Purpose of Review

Assessment of functional capacity is a cornerstone of preoperative risk assessment. While subjective clinician assessment of functional capacity is poorly predictive of postoperative outcomes, other objective functional assessment measures may provide more useful information.

Recent Findings

Cardiopulmonary exercise testing (CPET) is generally accepted as the gold standard for functional capacity assessment. However, CPET is resource-intensive and not universally available. Simpler objective tests of functional capacity such as the Duke Activity Status Index (DASI) and the 6-min walk test (6MWT) are cheap and efficient. In addition, they predict important postoperative outcomes including death, disability, and myocardial infarction.

Summary

Simple preoperative tests such as the DASI may be useful for routine preoperative assessment. CPET may be helpful to investigate further patients with functional status limitation, and to guide prehabilitation and perioperative shared decision-making in high-risk patients.

Extracellular Vesicles: A New Paradigm for Cellular Communication in Perioperative Medicine, Critical Care, and Pain Management

Extracellular vesicles (EVs) play critical roles in many health and disease states, including ischemia, inflammation, and pain, which are major concerns in the perioperative period and in critically ill patients. EVs are functionally active, nanometer-sized, membrane-bound vesicles actively secreted by all cells. Cell signaling is essential to physiological and pathological processes, and EVs have recently emerged as key players in intercellular communication. Recent studies in EV biology have improved our mechanistic knowledge of the pathophysiological processes in perioperative and critical care patients. Studies also show promise in using EVs in novel diagnostic and therapeutic clinical applications. This review considers the current advances and gaps in knowledge of EVs in the areas of ischemia, inflammation, pain, and in organ systems that are most relevant to anesthesiology, perioperative medicine, critical care, and pain management. We expect the reader will better understand the relationship between EVs and perioperative and critical care pathophysiological states and their potential use as novel diagnostic and therapeutic modalities.

[Preoperative stress testing in patients prior to vascular surgery]

Myocardial infarction is the leading cause of mortality during peripheral artery surgery. The review summarizes the data on cardiac event risk stratification in angiosurgical patients by preoperative stress testing. The prognostic value of positive and negative results is described. Stress testing with physical activity or pharmacological agents is rarely indicated in patients at low risk of major adverse cardiovascular events. Stress testing may be used in patients at increased risk of myocardial infarction (functional activity less than <4 metabolic equivalents), and if the test results should change the approaches to perioperative therapy, anesthesia or the volume of surgical intervention and, in rare situations, to perform coronary revascularization.

Modulation of Peripheral CD4+CD25+Foxp3+ Regulatory T Cells Ameliorates Surgical Stress-Induced Atherosclerotic Plaque Progression in ApoE-Deficient Mice

Systemic inflammation associated with major surgery rapidly accelerates atherosclerotic plaque progression in mice. Regulatory T cells (Tregs) have emerged as important modulators of atherogenesis. In coronary artery disease patients, low frequency of Tregs constitutes an independent risk factor for cardiovascular complications after non-cardiac surgery. In this exploratory analysis, we investigate whether preoperative Treg levels affect surgery-induced atherosclerotic lesion destabilization in a murine model of perioperative stress. After 9 weeks of high-cholesterol diet, atherosclerotic apolipoprotein E-deficient mice with modulated Treg levels were subjected to a 30-minute surgical procedure consisting of general isoflurane anesthesia, laparotomy and moderate blood loss. Controls underwent general anesthesia only. Brachiocephalic arteries were harvested 3 days after the intervention for histomorphological analyses of atherosclerotic plaques. Tregs were depleted by a single dose of anti-CD25 monoclonal antibody (mAb) administered 6 days prior to the intervention. Expansion of Tregs was induced by daily injections of IL-2/anti-IL-2 complex (IL-2C) on three consecutive days starting 3 days before surgery. Isotype-matched antibodies and PBS served as controls. Antibody-mediated modulation was Treg-specific. IL-2C treatment resulted in an eight-fold elevation of peripheral CD4⁺CD25⁺Foxp3⁺ Tregs compared to mice administered with anti-CD25 mAb. In mice treated with PBS and anti-CD25 mAb, surgical stress response caused a significant increase of atherosclerotic plaque necrosis (PBS: p < 0.001; anti-CD25 mAb: p = 0.037). Preoperative Treg expansion abrogated perioperative necrotic core formation (p = 0.556) and significantly enhanced postoperative atherosclerotic plaque stability compared to PBS-treated mice (p = 0.036). Postoperative plaque volume (p = 0.960), stenosis (p = 0.693), lesional collagen (p = 0.258), as well as the relative macrophage (p = 0.625) and smooth muscle cell content (p = 0.178) remained largely unaffected by preoperative Treg levels. In atherosclerotic mice, therapeutic expansion of Tregs prior to major surgery mitigates rapid effects on perioperative stress-driven atherosclerotic plaque destabilization. Future studies will show, whether short-term interventions modulating perioperative inflammation qualify for prevention of cardiovascular events associated with major non-cardiac surgery.

Expert Opinion Regarding Appropriately Timing Dermatological Surgeries in Patients With Recent Myocardial Infarctions

BACKGROUND

There is limited data on the risk of perioperative myocardial infarctions (MIs) in patients with a recent MI who undergo dermatologic surgeries.

OBJECTIVE

Present the recommendations of dermatologic surgeons and cardiologists to determine the safety of dermatologic surgeries after a recent MI.

METHODS

An electronic survey was distributed to Mohs surgeons and cardiologists to infer the risk of major adverse cardiac events (MACE) inherent to dermatologic surgery and determine timing of dermatologic surgery in patients with a recent MI.

RESULTS

One hundred twenty Mohs surgeons and 30 cardiologists were surveyed. Ninety-seven percent of cardiologists and 87% of Mohs surgeons deemed cutaneous excisions and Mohs micrographic surgery as low-risk procedures with less than one-percent chance of MACE. Seventy-seven percent of cardiologists and 46% of Mohs surgeons stated dermatologic surgery should either not be delayed or be delayed up to 1 month after an MI. Responses between cardiologists and Mohs surgeons did not significantly differ.

CONCLUSION

A preponderance of surveyed experts believe that most dermatologic surgeries may be safely performed in patients with a history of an MI within 1 month. The decision to implement urgent dermatologic surgery in patients with a recent MI should account for all clinically significant factors.

Perioperative myocardial injury and infarction following non-cardiac surgery: A review of the eclipsed epidemic

The perioperative period induces unpredictable and significant alterations in coronary plaque characteristics which may culminate as adverse cardiovascular events in background of a compromised myocardial oxygen supply and demand balance. This “ischemic-imbalance” provides a substrate for perioperative cardiac adversities which incur a considerable morbidity and mortality. The propensity of myocardial injury is dictated by the conglomeration of various factors like pre-existing medical condition, high-risk surgical interventions, intraoperative hemodynamic management, and the postoperative care. Perioperative myocardial infarction (PMI) differs from myocardial infarction (MI) in a non-operative setting. PMI can often be notoriously “silent” demonstrating a conspicuous absence of the classic clinical symptoms. Moreover, myocardial injury following non-cardiac surgery (MINS) characterized by an elevation of the cardiac insult biomarkers has demonstrated an independent prognostic significance in the perioperative scenario despite the lack of a formal categorization as PMI. This has evoked interest in the meticulous characterization of MINS as a discrete clinical entity. Multifactorial etiology, varying symptomatology, close differential diagnosis, and a debatable management regime makes perioperative myocardial injury-infarction, a subject of detailed discussion.

A feasibility study to investigate post-operative oxygen consumption (POpOC) after colorectal surgery requiring bowel resection

BACKGROUND

Oxygen consumption after surgery is increased in response to the tissue trauma sustained intra-operatively and the subsequent systemic inflammatory response that ensues. The cardio-respiratory system must match the tissue oxygen and metabolic requirements; otherwise, peri-operative complications may occur. Existing data is several decades old. The primary objective of this feasibility study was to determine the ease of recruiting participants and collecting relevant data to assess the extent and duration of increased oxygen consumption and post-operative complications after major abdominal surgery in contemporaneous times.

METHODS

One hundred patients scheduled for elective colorectal surgery requiring a bowel resection were screened to test specific feasibility criteria relating to ease of recruitment, duration of post-operative stay, ease of data collection, and drop-out rates. A calibrated metabolic cart was used to obtain unblinded pre-operative resting oxygen consumption recordings. The metabolic cart was then used to obtain post-operative oxygen consumption readings on days 1 to 5 as long as the participant remained as an inpatient. At the time of the oxygen consumption reading, a Post-Operative Morbidity Survey score (POMS) was calculated. Feasibility outcomes chosen a priori were that at least one participant would be recruited every 2 weeks from the pre-admission colorectal clinic, at least 10% of potential subjects screened would be enrolled, at least 80% of recruited participants would have a minimum post-operative stay of 2 nights, a minimum of 3 consecutive days of oxygen consumption data would be collected for each subject, at least 8 of 9 POMS score domains would be completed per participant per day and the drop-out rate would be no greater than 10%. We deemed that screening 100 patients would be sufficient to test our feasibility outcomes.

RESULTS

Twelve participants completed the protocol. All pre-specified feasibility criteria were met. No increase in post-operative oxygen consumption was observed in this feasibility cohort.

CONCLUSIONS

The protocol and experiences gained from this feasibility study could be used to plan a larger study to better define changes in post-operative oxygen consumption after major abdominal surgery utilizing current surgical techniques.

Computed tomographic coronary angiography in risk stratification prior to non-cardiac surgery: a systematic review and meta-analysis

OBJECTIVES

Utility of CT coronary angiography (CTA) and coronary artery calcium (CAC) scoring in risk stratification prior to non-cardiac surgery is unclear. Although current guidelines recommend stress testing in intermediate-high risk individuals, over one-third of perioperative major adverse cardiovascular events (MACE) occur in patients with a negative study. This systematic review and meta-analysis evaluates the value of CTA and CAC score in preoperative risk prognostication prior to non-cardiac surgery.

METHODS

MEDLINE, PubMed and EMBASE databases were searched for articles published up to June 2018. Summary ORs for degree of coronary artery disease (CAD) and perioperative MACE were pooled using a random-effects model.

RESULTS

Eleven studies were included. Two hundred and fifty-two (7.2%) MACE occurred in 3480 patients. Risk of perioperative MACE rose with the severity and extent of CAD on CTA (no CAD 2.0%; non-obstructive 4.1%; obstructive single-vessel 7.1%; obstructive multivessel 23.1%, p<0.001). Multivessel disease (MVD) demonstrated the greatest risk (OR 8.9, 95% CI 5.1 to 15.3, p<0.001). Increasing CAC score was associated with higher perioperative MACE (CAC score: ≥100 OR 5.1, ≥1000 OR 10.4, both p<0.01). In a cohort deemed high risk by established clinical indices, absence of MVD on CTA demonstrated a negative predictive value of 96% (95% CI 92.8 to 98.4) for predicting freedom from MACE.

CONCLUSIONS

Severity and extent of CAD on CTA conferred incremental risk for perioperative MACE in patients undergoing non-cardiac surgery. The 'rule-out' capability of CTA is comparable to other non-invasive imaging modalities and offers a viable alternative for risk stratification of patients undergoing non-cardiac surgery.

TRIAL REGISTRATION NUMBER

CRD42018100883.

Hip Fracture, Comorbidity, and the Risk of Myocardial Infarction and Stroke: A Danish Nationwide Cohort Study, 1995-2015

We evaluated risks of MI and stroke in elderly patients with hip fracture compared with the general population. We also examined the interaction between hip fracture and comorbidity with respect to risks of MI or stroke, defined as excess of risk explained by combining risks of hip fracture and comorbidity. We conducted a population-based cohort study using Danish health registries, in 1995 to 2015 including 110,563 hip fracture patients and 552,774 members of the comparison cohort from the general population. Thirty-day cumulative incidences of MI were 1.15% among patients with hip fracture and 0.09% in the general population (adjusted hazard ratio [aHR] = 12.97; 95% confidence interval [CI], 11.56 to 14.55). Thirty-day cumulative incidences of stroke were 2.16% for hip fracture patients and 0.21% in the general population (aHR = 9.42; 95% CI, 8.71 to 10.19). During the 31 to 365 days following hip fracture, the aHR for MI was 1.05 (95% CI, 0.97 to 1.14) and remained at this level during the remainder of follow-up (maximum of 20 years). The aHR for stroke was 1.29 (95% CI, 1.22 to 1.35) during the 31 to 365 days following hip fracture, remained elevated for up to 10 years, and then decreased to the general population level. The aHRs for MI and stroke were increased for both men and women, and in all age and comorbidity groups. During the first 30 days, up to 76% of MI and stroke risk was attributable to interaction between hip fracture and comorbidity. Patients with hip fracture are at increased risk of both MI and stroke up to 1 year following the fracture. Risk of stroke, but not of MI, was elevated during up to 10 years postfracture. Although the absolute risks were low, our finding underscores the importance of targeting multimorbidity, including prevention and adequate treatment, to improve the prognosis of hip fracture patients. © 2017 American Society for Bone and Mineral Research.

Thrombin induced platelet-fibrin clot strength in relation to platelet volume indices and inflammatory markers in patients with coronary artery disease

Platelet aggregation and inflammation are both implicated in coronary artery disease (CAD). Thrombin induced platelet-fibrin clot strength (MA_Thrombin) measured by thrombelastography (TEG) has been proved to be a novel marker of platelet aggregation. The aim of this study was to investigate the correlation of MA_Thrombin to platelet volume indices (PVIs) or to inflammatory markers in different types of CAD. 206 patients with different types of CAD were enrolled. MA_Thrombin, PVIs, including mean platelet volume (MPV), platelet distribution width (PDW), and platelet-large cell ratio (P-LCR) as well as inflammatory markers, including high-sensitivity C-reactive protein (hs-CRP) and fibrinogen (Fbg) were measured. Multiple linear regression models were used to analyze the association between MA_Thrombin, PVIs, and inflammatory markers. MA_Thrombin and inflammatory markers both varied with CAD types (P<0.001). MA_Thrombin was correlated to PVIs in NSTEMI individuals (MPV, r=0.393, P=0.007; PDW, r=0.334, P=0.023; P-LCR, r=0.382, P=0.008), but had inner-link with inflammatory markers in STEMI cases (hs-CRP, r=0.499, P<0.001; Fbg, r=0.500, P<0.001). These findings may suggest different mechanisms of platelet aggregation in different types of CAD. Moreover, MA_Thrombin may be used as a potential parameter to evaluate platelet aggregation and inflammation together.

Postoperative Extracorporeal Membrane Oxygenation Support for Acute Type A Aortic Dissection

BACKGROUND

Few studies have investigated the use of postoperative extracorporeal membrane oxygenation (ECMO) in acute type A aortic dissection (aTAAD). We identified aTAAD surgical patients at risk of ECMO implantation postoperatively and analyzed the prognosis of these patients.

METHODS

We retrospectively reviewed 162 consecutive aTAAD patients undergoing operations from January 2008 to December 2015. Patient data were analyzed for risk factors leading to an ECMO requirement. Short-term and long-term outcomes in patients who did and did not require ECMO were compared.

RESULTS

Postoperative ECMO was required in 20 patients (12.3%), and in-hospital mortality was higher in the ECMO group (65.0% vs 8.5%, p < 0.001). Factors predicting postoperative ECMO were preoperative hemodynamic instability (p = 0.049), aortic cross-clamp time (p = 0.036), and postoperative peak creatinine kinase-MB (p = 0.002). ECMO survivors presented at a younger age (p = 0.036) and had a less postoperative blood transfusion (p = 0.034) than ECMO nonsurvivors. The postdischarge survival rate was equivalent in patients with or without ECMO support.

CONCLUSIONS

Although postoperative ECMO is an important predictor of in-hospital death, this pilot study showed that aTAAD patients supported with postoperative ECMO who survive to hospital discharge have a long-term survival comparable to patients who did not receive ECMO.

Incomplete Revascularization Is Associated With an Increased Risk for Major Adverse Cardiovascular Events Among Patients Undergoing Noncardiac Surgery

OBJECTIVES

The aim of this study was to determine whether incomplete revascularization is associated with a higher risk for major adverse cardiovascular events (MACE) and myocardial infarction (MI) among patients undergoing noncardiac surgery.

BACKGROUND

Patients with coronary artery disease and prior percutaneous coronary intervention (PCI) frequently undergo noncardiac surgery. These patients may have had PCI either on all obstructive lesions (i.e., complete revascularization) or only on some (i.e., incomplete revascularization).

METHODS

Patients were identified using the Veterans Affairs Clinical Assessment, Reporting, and Tracking program. Veterans Affairs and non-Veterans Affairs surgical records were used to link patients who underwent noncardiac surgery within 2 years after stent placement. Incomplete revascularization was defined as a residual stenosis of ≥50% in the left main coronary artery or ≥70% in another major epicardial coronary artery on the basis of operator visual estimate.

RESULTS

In total, 4,332 patients (34.7%) had incomplete revascularization. A total of 567 MACE occurred within 1 month post-operatively. Patients with incomplete revascularization had an unadjusted 19% increased odds of post-operative MACE, compared with those with complete revascularization (odds ratio: 1.19; 95% confidence interval [CI]: 1.00 to 1.41). Among the MACE components, post-operative MI appears to contribute the most, with a 37% increased risk for post-operative MI among patients with incomplete revascularization (odds ratio: 1.37; 95% CI: 1.10 to 1.70). After adjustment, there was a significant interaction between time from PCI and outcomes after noncardiac surgery; incomplete revascularization was associated with significantly increased risk for post-operative MI primarily if surgery was performed within 6 weeks after PCI (adjusted odds ratio: 1.84; 95% CI: 1.04 to 2.38). The number of vessels with incomplete revascularization was also associated with an increased risk for post-operative MI: for each additional vessel with incomplete revascularization, there was a 17% increased odds of post-operative MI.

CONCLUSIONS

Incomplete revascularization among patients with coronary artery disease is associated with an increased risk for MI after noncardiac surgery.

Perioperative β-Blockade in Noncardiac Surgery: A Cautionary Tale of Over-reliance on Small Randomized Prospective Trials

PURPOSE

Our aim was to analyze the current scientific literature relevant to the use of β-adrenergic receptor antagonists for the prevention of cardiovascular morbidity and mortality in patients undergoing noncardiac surgery.

METHODS

A PubMed search was conducted for the following concepts: pre- or perioperative, β-adrenergic receptor antagonist, treatment outcome, and cardiovascular complication. Randomized clinical trials measuring the effect of β-adrenergic blocking agents against that of placebo on cardiovascular outcomes after noncardiac surgery were included in the review.

FINDINGS

Two small randomized controlled trials published in 1996 and 1999 reported associations between perioperative β-blockade and significant reductions in long-term and 30-day cardiac mortality, respectively. These 2 studies prompted guideline changes in 2002 encouraging perioperative β-blockade in subsets of noncardiac surgery patients. However, subsequent trials failed to validate these results. In 2008, the first large randomized controlled trial on the topic was published and found an association between perioperative β-blockade and an increase in perioperative mortality. Furthermore, in 2011, the lead author of the 1999 study was dismissed from his academic position for scientific misconduct, casting doubt on the validity of guidelines based on his work. Existing studies are highly heterogeneous, making comparisons difficult. Current literature does not support initiating perioperative β-blockade in noncardiac surgery patients not already receiving these medications.

IMPLICATIONS

Future research on the topic should account for the influence individual genetic variation can have on outcomes and β-blocker metabolism. Additionally, the relationship between outcomes and the β-1 selectivity of different β-blockers should be explored.

Plasma levels of growth differentiation factor-15 are associated with myocardial injury in patients undergoing off-pump coronary artery bypass grafting

Growth differentiation factor-15 (GDF-15) has recently emerged as a risk predictor in patients with cardiovascular diseases. We therefore aimed to investigate the role of GDF-15 in the occurrence of cardiac injury during off-pump coronary artery bypass grafting (OPCAB). 55 consecutive patients with coronary artery diseases were recruited in this prospective, observational study. All patients were operated for OPCAB surgery. Serial blood samples were collected preoperatively, 12 hours and 36 hours after surgery. GDF-15, together with C-reactive protein, cardiac troponin I, creatine kinase MB and N-terminal pro B-type natriuretic peptide levels in plasma were measured at each time-point. GDF-15 levels increased significantly at 12 hours after surgery, attaining nearly 2.5 times the baseline levels (p < 0.001). Postoperative GDF-15 levels correlated positively with cTnI (p = 0.003) and EuroSCORE II (p = 0.013). According to the ROC curves, postoperative plasma GDF-15 was found to be the best biomarker to predict perioperative cardiac injury, compared with cTnI, CK-MB and EuroSCORE II. Circulating GDF-15 is a promising novel biomarker for identifying perioperative myocardial injury in patients undergoing OPCAB.

Early cardiology assessment and intervention reduces mortality following myocardial injury after non-cardiac surgery (MINS)

BACKGROUND

Myocardial injury after non-cardiac surgery (MINS) is defined as troponin elevation of ≥0.03 ng/mL associated with 3.87-fold increase in early mortality. We sought to determine the impact of cardiology intervention on mortality in patients who developed MINS after general thoracic surgery.

METHODS

A retrospective review was performed in patients over 5 years. Troponin was routinely measured and levels ≥0.04 ng/mL classified as positive. Data acquisition and mortality status was obtained via medical records and NHS tracing systems. Thirty-day mortality was compared on MINS cohort using Fisher's exact square testing and logistic regression analysis.

RESULTS

Troponin levels were measured in 491 (96%) of 511 patients. Eighty (16%) patients fulfilled the MINS criteria. Sixty-one (76%) received early cardiology consult and "myocardial infarction" stated in four (5%) patients. Risk assessment (for AMI) was undertaken; 20 (25%) patients were commenced on aspirin, four (5%) on β-blockers and one (1%) underwent percutaneous coronary intervention. Forty-nine (61%) patients received primary risk factor modifications and 26 (33%) had outpatient follow-up. There were no significant differences in the proportion of patients who died within 30 days post-operatively in the MINS group of 2.6% compared to the non-MINS group of 1.6% (P=0.625). The odds ratio for 30-day mortality in the MINS group was 1.69 (95% CI: 0.34 to 8.57, P=0.522).

CONCLUSIONS

MINS is common after general thoracic surgery. Early cardiology intervention reduced the expected hazard ratio of early death from 3.87 to an odds ratio of 1.69 with no significant difference in 30-day mortality for patients who developed MINS.

Preoperative β-blockers do not improve cardiac outcomes after major elective vascular surgery and may be harmful

OBJECTIVE

Routine initiation β-blocker medications before vascular surgery is controversial due to conflicting data. The purpose of this analysis was to determine whether prophylactic use of β-blockers before major elective vascular surgery decreased postoperative cardiac events or mortality.

METHODS

The Society for Vascular Surgery Vascular Quality Initiative (SVS-VQI) data set was used to perform a retrospective cohort analysis of infrainguinal lower extremity bypass (LEB), aortofemoral bypass (AFB), and open abdominal aortic aneurysm (AAA) repair patients. Chronic (>30 days preoperatively) β-blocker patients were excluded, and comparisons were made between preoperative (0-30 day) and no β-blocker groups. Patients were risk stratified using a novel prediction tool derived specifically from the SVS-VQI data set. Propensity-matched pairs and interprocedural specific risk stratification comparisons were performed. End points included in-hospital major adverse cardiac events (MACEs), including myocardial infarction (MI; defined as new ST or T wave electrocardiographic changes, troponin elevation, or documentation by echocardiogram or other imaging modality), dysrhythmia, and congestive heart failure, and 30-day mortality.

RESULTS

The study analyzed 13,291 patients (LEB, 68% [n = 9047]; AFB, 11% [n = 1474]; and open AAA, 21% [n = 2770]); of these, 67.7% (n = 8999) were receiving β-blockers at time of their index procedure. Specifically, 13.2% (n = 1753) were identified to have been started on a preoperative β-blocker, 54.5% (n = 7426) were on chronic β-blockers, and 32.3% (n = 4286) were on no preoperative β-blockers. Among the three procedures, patients had significant demographic and comorbidity differences and thus were not combined. A 1:1 propensity-matched pairs analysis (1459 pairs) revealed higher rates of postoperative MI with preoperative β-blockers (preoperative β-blocker relative risk, 1.65; 95% confidence interval, 1.02-2.68; P = .05 vs no β-blocker), with no difference in dysrhythmia, congestive heart failure, or 30-day mortality. When stratified into low-risk, medium-risk, and high-risk groups within each procedure, all groups of preoperative β-blocker patients had no difference or higher rates of MACEs and 30-day mortality, with the exception of high-risk open AAA patients, who had a lower rate of MI (odds ratio, 0.35; 95% confidence interval, 011-0.87; P = .04).

CONCLUSIONS

Exclusive of high-risk open AAA patients, preoperative β-blockers did not decrease rates of MACEs or mortality after LEB, AFB, or open AAA. Importantly, exposure to prophylactic preoperative β-blockers increased the rates of some adverse events in several subgroups. Given these data, the SVS-VQI cannot support routine initiation of preoperative β-blockers before major elective vascular surgery in most patients.

Intraoperative cardiac emergencies

Intraoperative cardiac emergencies require prompt recognition and management in order to optimize patient safety and recovery. This article addresses the perioperative management of hypertension, myocardial infarction, arrhythmias, autonomic dysreflexia, tamponade, and tension pneumothorax. These complications can occur in patients with underlying coexisting disease, but can also occur in surgical patients regardless of the underlying disorder.

A case-cohort study of postoperative myocardial infarction: impact of anemia and cardioprotective medications

OBJECTIVE

Postoperative myocardial infarction (poMI) is a serious and costly complication. Multiple risk factors for poMI are known, but the effect of anemia and cardioprotective medications have not been defined in real-world surgical practice.

METHODS

Patients undergoing inpatient elective surgery were assessed at 17 hospitals from 2008 to 2011 for the occurrence of poMI (American Heart Association definition). Non-MI control patients were chosen randomly on the basis of case type. Descriptive, univariable, and multivariable statistical analysis were performed for primary outcomes of poMI and death at 30 days.

RESULTS

Compared with controls (N = 304), patients with poMI (N = 222) were older (72 ± 11 vs 60 ± 17 years, P < .0001), had a lesser preoperative hematocrit (37 ± 6 vs 39 ± 5, P < .0001), more often were smokers, had a preoperative T-wave abnormality (21% vs 9%, P < .0001), and had a preoperative stress test with a fixed deficit (26% vs 3%; P < .001). Preoperative factors associated with poMI included peripheral vascular disease (odds ratio 2.6; 95% confidence interval 1.3-5.3), tobacco use (1.7; 1.01-2.9), history of percutaneous coronary angioplasty (2.8; 1.6-5.0), and age (1.05; 1.03-1.07), whereas hematocrit >35 (0.51; 0.32-0.82) and preoperative acetylsalicylic acid, ie, aspirin (0.59; 0.4-0.97) were protective. Preoperative β-blockade, statin, and use of angiotensin-converting enzyme inhibitors were not associated with lesser rates of poMI. Non-MI complication rates were 23-fold greater in the poMI group compared with the control group (P < .0001). Mortality with poMI within 30 days was 11% compared with 0.3% in non-MI control patients (P < .0001). In patients with poMI, factors independently associated with death included use of epidurals (3.5; 1.07-11.4) and bleeding (4.2; 1.1-16), whereas preoperative use of aspirin (0.29; 0.1-0.88), and postoperative β-blockade (0.18; 0.05-0.63) were protective. Cardiac catheterization, percutaneous coronary intervention, or coronary artery bypass grafting after poMI was performed in 34% of those alive and 20% of those who died (P = .16).

CONCLUSION

In the current era, poMI patients have a markedly increased risk of death. This risk is decreased with preoperative use of acetylsalicylic acid and post MI β-blockade. Further study is warranted to explore the role of anemia and cardiac interventions after poMI.

Do Preoperative β-blockers Improve Postoperative Outcomes in Patients Undergoing Cardiac Surgery? Challenging Societal Guidelines

Preoperative β-blockers (BBs) are widely administered to reduce morbidity and mortality among surgical patients. In fact, the Society of Thoracic Surgeons uses the administration of preoperative BBs as a quality metric. Recent reports, however, have questioned the benefit and safety of pre-operative BB administration. The aim of our study was to investigate whether preoperative BBs lead to improved surgical outcomes in patients undergoing cardiac surgery. A review of our prospectively maintained institutional database was done to identify adults undergoing cardiac operations at our institution from 2008 to 2013. Survival to discharge was the primary outcome with several additional secondary measures of morbidity included. A total of 2120 patients were included in the analysis and a multivariate logistic regression model was developed to adjust for differences between patient groups. After adjustment, BB administration was associated with lower odds of both prolonged ventilation (odds ratio [OR], 0.73; P = 0.032) and prolonged length of stay (OR, 0.79; P = 0.044). BB use was not associated with significant differences in other outcomes such as mortality or postoperative atrial fibrillation. Our study found that preoperative BBs may not be associated with sufficiently improved outcomes to justify their use as a quality metric in this population. Thus, prospective studies are warranted.

Plasma levels of microRNA-499 provide an early indication of perioperative myocardial infarction in coronary artery bypass graft patients

BACKGROUND

Recent studies indicated that microRNAs (miRNAs, miRs) were important for many biological and pathological processes, and they might be potential biomarkers for cardiovascular diseases. The present study aims to determine the release patterns of miRNAs in cardiac surgery and to analyze the ability of miRs to provide early prediction of perioperative myocardial infarction (PMI) in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODOLOGY/PRINCIPAL FINDINGS

Thirty on-pump CABG patients were recruited in this study; and miR-499, miR-133a and miR-133b, cardiac troponin I (cTnI) were selected for measurement. Serial plasma samples were collected at seven perioperative time points (preoperatively, and 1, 3, 6, 12, 24, and 48 hours after declamping) and were tested for cTnI and miRs levels. Importantly, miR levels peaked as early as 1-3 hours, whereas cTnI levels peaked at 6 hours after declamping. Peak plasma concentrations of miRs correlated significantly with cTnI (miR-499, r = 0.583, P = 0.001; miR-133a, r = 0.514, P = 0.006; miR-133b, r = 0.437, P = 0.05), indicating the degree of myocardial damage. In addition, 30 off-pump CABG patients were recruited; miR-499 and miR-133a levels were tested, which were significantly lower in off-pump group than in on-pump group. A prospective cohort of CABG patients (n = 120) was recruited to study the predictive power of miRs for PMI. The diagnosis of PMI strictly adhered to the principles of universal definition of myocardial infarction. The data analysis revealed that miR-499 had higher sensitivity and specificity than cTnI, and indicated that miR-499 could be an independent risk factor for PMI.

CONCLUSION

Our results demonstrate that circulating miR-499 is a novel, early biomarker for identifying perioperative myocardial infarction in cardiac surgery.

Predicting major adverse cardiac events in spine fusion patients: is the revised cardiac risk index sufficient?

STUDY DESIGN

Observational cohort study.

OBJECTIVE

To determine the accuracy of the Revised Cardiac Risk Index (RCRI) in predicting major adverse cardiac events in patients undergoing spine fusion surgery of 3 levels or more.

SUMMARY OF BACKGROUND DATA

Preoperative cardiac testing is extensively guided by the RCRI, which was developed and validated in thoracic, abdominal, and orthopedic surgical patients. Because multilevel spine fusion surgery is often associated with major transfusion, we hypothesize that the RCRI may not accurately characterize the risk of cardiovascular morbidity in these patients.

METHODS

After institutional review board approval, perioperative data were collected from 547 patients who underwent 3 or more levels of spinal fusion with instrumentation. Postoperative cardiac morbidity was defined as any combination of the following: arrhythmia requiring medical treatment, myocardial infarction (either by electrocardiographic changes or troponin elevation), or the occurrence of demand ischemia. The surgical complexity was categorized as anterior surgery only, posterior cervical and/or thoracic fusion, posterior lumbar fusion, or any surgery that included transpedicular osteotomies. Logistic regression analysis was performed to determine RCRI performance.

RESULTS

The RCRI performed no better than chance (area under the curve = 0.54) in identifying the 49 patients (9%) who experienced cardiac morbidity.

CONCLUSION

The RCRI did not predict cardiac morbidity in our patients undergoing major spine fusion surgery, despite being extensively validated in low-risk noncardiac surgical patients. Preoperative testing and optimization decisions, previously based on the RCRI, may need to be revised to include more frequent functional cardiac imaging and more aggressive implementation of pharmacologic modalities that may mitigate cardiac morbidity, similar to the preoperative evaluation for major vascular surgery.

LEVEL OF EVIDENCE

3.

Usefulness of troponin T to predict short-term and long-term mortality in patients after hip fracture

The purpose was to evaluate the short-term (30-day) and long-term (1,000-day) prognostic values of perioperative troponin T (TnT) and electrocardiographic (ECG) findings in hip fracture patients. A consecutive cohort of 200 patients (68 men) was enrolled. Blinded TnT levels and ECG were assessed on admission, before operation, and on first and second postoperative days. Median (interquartile range) follow-up time was 3.1 (0.3) years. TnT elevation was observed in 71 patients (35.5%): already before the operation in 36 patients (51%) and only after surgery in 35 patients (49%). New ischemic ECG changes were detected in 101 of 194 patients (52%), including 7 ST elevations. Patients with TnT elevation had higher short-term (17% vs 4.7%, respectively, p=0.008) and long-term (61% vs 40%, respectively, p=0.005) mortality, the short-term mortality being higher in patients with major (TnT≥0.15 μg/L) compared with minor TnT elevation (24% vs 13%, respectively, p=0.005). TnT elevation was the only independent predictor of short-term mortality (hazard ratio [HR] 3.87, 95% confidence interval [CI] 1.45 to 10.3, p=0.007), whereas TnT elevation (HR 1.73, 95% CI 1.14 to 2.64, p=0.01), increasing age (HR 1.03, 95% CI 1.01 to 1.06, p=0.01), dementia (HR 1.84, 95% CI 1.22 to 2.78, p=0.004), and atrial fibrillation (HR 1.86, 95% CI 1.18 to 2.93, p=0.007) remained independent predictors of long-term mortality. ECG findings other than ST elevation did not affect mortality. In conclusion, elevated perioperative TnT level is a strong predictor of short-term and long-term mortality. Routine TnT measurements and earlier diagnosis together with appropriate treatment may improve survival of this fragile patient group.

Perioperative management of antiplatelet therapy

Worldwide, cardiovascular events represent the major cause of morbidity and mortality. A key role in the pathogenesis of these events is played by platelets. Interventional procedures, with placement of coronary and vascular stents, often represent the preferred therapeutic strategy. Antiplatelet medications are considered first-line therapy in preventing cardiovascular thrombotic events. A wide array of antiplatelet agents is available, each with different pharmacological properties. When patients on antiplatelet agents present for surgery, the perioperative team must design an optimal strategy to manage antiplatelet medications. Each patient is stratified according to risk of developing a cardiovascular thrombotic event and inherent risk of surgical bleeding. After risk stratification analysis, various therapeutic pathways include continuing or discontinuing all antiplatelet agents or maintaining one antiplatelet agent and discontinuing the other. This review focuses on the pharmacological and pharmacokinetic properties of both older and novel antiplatelet drugs, and reviews current literature and guidelines addressing options for perioperative antiplatelet management.

Recurrent intraoperative silent ST depression responding to phenylephrine

Intraoperative myocardial ischemia is attributed to decreased myocardial oxygen supply. We present an unusual case of recurrent, symptomless inferior wall ischemia in an apparently healthy male with no history of coronary artery disease after a spinal block. The recurring episodes were linked to tachycardia and presented with significant ST depression in Lead II with reciprocal elevation in lead aVL. The episodes responded to phenylephrine and subsided without residual sequelae.