Myocardial infarction after vascular surgery: the role of prolonged stress-induced, ST depression-type ischemia

Antiplatelet therapy and long-term mortality in patients with myocardial injury after non-cardiac surgery

BACKGROUNDS

Myocardial injury after non-cardiac surgery (MINS) has recently been accepted as a common complication associated with increased mortality. However, little is known about the treatment of MINS. The aim of this study was to investigate an association between antiplatelet therapy and long-term mortality after MINS.

METHODS

From 2010 to 2019, patients with MINS, defined as having a peak high-sensitivity troponin I higher than 40 ng/L within 30 days after non-cardiac surgery, were screened at a tertiary centre. Patients were excluded if they had a history of coronary revascularisation before or during index hospitalisation. Clinical outcomes at 1 year were compared between patients with and without antiplatelet therapy at hospital discharge. The primary outcome was death, and the secondary outcome was major bleeding.

RESULTS

Of the 3818 eligible patients with MINS, 940 (24.6%) received antiplatelet therapy at hospital discharge. Patients with antiplatelet therapy had a significantly lower mortality at 1 year than those without antiplatelet therapy (7.5% vs 15.9%, adjusted HR 0.60, 95% CI 0.45 to 0.79, p<0.001). A risk of major bleeding at 1 year was not significantly different between the patients with and without antiplatelet therapy (6.6% vs 7.6%, adjusted HR 0.85, 95% CI 0.62 to 1.17, p=0.324). In propensity score-matched analysis of 886 pairs, patients with antiplatelet therapy had a significantly lower risk of 1-year mortality (adjusted HR 0.53, 95% CI 0.39 to 0.73, p<0.001) than those without antiplatelet therapy.

CONCLUSIONS

In patients with MINS, antiplatelet therapy at discharge was associated with decreased 1-year mortality.

Long-term outcomes of perioperative myocardial infarction/injury after non-cardiac surgery

AIMS

Perioperative myocardial infarction/injury (PMI) following non-cardiac surgery is a frequent cardiac complication. Better understanding of the underlying aetiologies and outcomes is urgently needed.

METHODS AND RESULTS

Aetiologies of PMIs detected within an active surveillance and response programme were centrally adjudicated by two independent physicians based on all information obtained during clinically indicated PMI work-up including cardiac imaging among consecutive high-risk patients undergoing major non-cardiac surgery in a prospective multicentre study. PMI aetiologies were hierarchically classified into 'extra-cardiac' if caused by a primarily extra-cardiac disease such as severe sepsis or pulmonary embolism; and 'cardiac', further subtyped into type 1 myocardial infarction (T1MI), tachyarrhythmia, acute heart failure (AHF), or likely type 2 myocardial infarction (lT2MI). Major adverse cardiac events (MACEs) including acute myocardial infarction, AHF (both only from day 3 to avoid inclusion bias), life-threatening arrhythmia, and cardiovascular death as well as all-cause death were assessed during 1-year follow-up. Among 7754 patients (age 45-98 years, 45% women), PMI occurred in 1016 (13.1%). At least one MACE occurred in 684/7754 patients (8.8%) and 818/7754 patients died (10.5%) within 1 year. Outcomes differed starkly according to aetiology: in patients with extra-cardiac PMI, T1MI, tachyarrhythmia, AHF, and lT2MI 51%, 41%, 57%, 64%, and 25% had MACE, and 38%, 27%, 40%, 49%, and 17% patients died within 1 year, respectively, compared to 7% and 9% in patients without PMI. These associations persisted in multivariable analysis.

CONCLUSION

At 1 year, most PMI aetiologies have unacceptably high rates of MACE and all-cause death, highlighting the urgent need for more intensive treatments.

STUDY REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02573532.

Current management of coronary artery disease prior to vascular surgery: A clinical dilemma

Here we present a case of an elderly man who underwent cardiac stress testing as a preoperative evaluation prior to femoral-popliteal bypass surgery. He subsequently underwent a preoperative coronary angiogram after a high-risk stress test with the latter demonstrating obstructive three-vessel coronary artery disease. We discuss the clinical challenges that such a common clinical scenario presents particularly when it comes to preoperative coronary revascularisation prior to vascular surgery. We examine the case within the framework of the latest revascularisation guidelines and discuss the available evidence for preoperative revascularisation and its limitations.

Tracheal Extubation Under Deep Anesthesia Using Transnasal Humidified Rapid Insufflation Ventilatory Exchange vs. Awake Extubation: An Open-Labeled Randomized Controlled Trial

Background

Tracheal extubation can be associated with several complications, including desaturation, agitation, hypertension, and tachycardia. We hypothesize that the use of transnasal humidified rapid insufflation ventilator exchange (THRIVE) immediately after extubation under deep anesthesia reduces the incidence of these adverse events.

Methods

One hundred patients who underwent elective abdominal surgery under general anesthesia were randomly assigned to undergo tracheal extubation under deep anesthesia employing THRIVE (THRIVE group) or awake extubation (CONTROL group). The primary outcome was the incidence of experiencing desaturation (SpO₂ < 90%) at any time during emergence from anesthesia. Secondary outcomes included variations in heart rate and blood pressure, comfort level, bucking, and agitation.

Results

The THRIVE group showed a lower incidence of desaturation than the CONTROL group (12 vs. 54%, OR = 0.22 [95% CI, 0.10-0.49], P < 0.001). Less patients in the THRIVE group experienced a 20% (or more) increase in mean arterial pressure (4 vs. 26%, OR = 0.15 [95% CI, 0.04-0.65], P = 0.002). THRIVE patients did not suffer from agitation or bucking, while in the CONTROL group agitation and bucking occurred in 22 and 58% of the patients, respectively. Additionally, the THRIVE group showed a lower incidence of uncomfortable experience than the CONTROL group (8 vs. 36%, OR = 0.22 [95% CI, 0.08-0.61], P = 0.001).

Conclusion

Tracheal extubation under deep anesthesia using THRIVE decreases the incidence of desaturation and adverse haemodynamic events and increases patient satisfaction. Extubation under deep anesthesia using THRIVE might be an alternative strategy in selected patient populations.

Perioperative Myocardial Infarction in Free Flap for Head and Neck Reconstruction

INTRODUCTION

Acute myocardial infarction (AMI) is a postoperative complication of major surgical procedures, including free flap surgery. It is the most common cause of postoperative morbidity and mortality. Moreover, patients receiving free flap reconstruction for the head and neck have significant risk factors such as coexisting coronary artery disease (CAD). Our primary aim was to ascertain predictors of perioperative AMI to enable early detection and consequently early treatment of perioperative AMI. Our secondary aim was to determine the group of patients who would be at a high risk for perioperative AMI after free flap surgery.

MATERIALS AND METHODS

This retrospective study enrolled patients who underwent free flap reconstruction surgery at the Division of Plastic and Reconstructive Surgery of Taipei Veterans General Hospital between 2013-01 and 2017-12.

RESULTS

This study included 444 patients and 481 free flap head and neck reconstruction surgeries. Fifteen (3.1%) patients were diagnosed with perioperative AMI. Statistical analysis of the variables revealed that patients with underlying CAD or cerebrovascular accident (CVA) were at a high risk of developing perioperative AMI (odds ratio: 6.89 and 11.11, respectively). The flap failure rate was also higher in patients with perioperative AMI compared with those without perioperative AMI (P = 0.015).

CONCLUSIONS

Patients with underlying diseases, such as CAD or CVA, constituted high-risk groups for perioperative AMI.

Patient Selection for Routine Troponin Monitoring After Noncardiac Surgery

Background

Myocardial infarction is an important complication after noncardiac surgery. Therefore, perioperative troponin surveillance is recommended for patients at risk. The aim of this study was to identify patients at high risk of perioperative myocardial infarction (POMI), in order to aid appropriate selection and to omit redundant laboratory measurements in patients at low risk.

Methods and Results

This observational cohort study included patients ≥60 years of age who underwent intermediate to high risk noncardiac surgery. Routine postoperative troponin I monitoring was performed. The primary outcome was POMI. Classification and regression tree analysis was used to identify patient groups with varying risks of POMI. In each subgroup, the number needed to screen to identify 1 patient with POMI was calculated. POMI occurred in 216 (4%) patients and other myocardial injury in 842 (15%) of the 5590 included patients. Classification and regression tree analysis divided patients into 14 subgroups in which the risk of POMI ranged from 1.7% to 42%. Using a risk of POMI ≥2% to select patients for routine troponin I monitoring, this monitoring would be advocated in patients ≥60 years of age undergoing emergency surgery, or those undergoing elective surgery with a Revised Cardiac Risk Index class >2 (ie >1 risk factor). The number needed to screen to detect a patient with POMI would be 14 (95% CI 14–14) and 26% of patients with POMI would be missed.

Conclusions

To improve selection of high‐risk patients ≥60 years of age, routine postoperative troponin I monitoring could be considered in patients undergoing emergency surgery, or in patients undergoing elective surgery classified as having a revised cardiac risk index class >2.

Type 2 Myocardial Infarction: JACC Review Topic of the Week

Acute myocardial infarction (MI) can occur from increased myocardial oxygen demand and/or reduced supply in the absence of acute atherothrombotic plaque disruption; a condition called type 2 myocardial infarction (T2MI). As with any MI subtype, there must be clinical evidence of myocardial ischemia to make the diagnosis. This condition is increasingly diagnosed due to the increasing sensitivity of cardiac troponin assays and is associated with adverse short-term and long-term prognoses. Limited data exist defining optimal management strategies because T2MI is a heterogeneous entity with varying etiologies and triggers. Thus, these patients require individualized care. A major barrier is the absence of a uniform definition that can be operationalized with high reproducibility. This document provides a synthesis of the data about T2MI to assist clinicians' understanding of its pathobiology, when to deploy the diagnosis, and its associated treatments. It also clarifies prognosis, identifies gaps in knowledge, and provides recommendations for moving forward.

Estimating Regional Myocardial Contraction Using Miniature Transducers on the Epicardium

This paper describes an ultrasound system to monitor cardiac motion using miniature transducers attached directly to the epicardial surface. Our aim was to develop both a research tool for detailed studies of cardiac mechanics and a continuous, real time system for peri-operative evaluation of heart function. The system was tested on a porcine model. Two 3 mm diameter, 10 MHz ultrasound transducers were sutured to the epicardial surface. As the epicardial surface was the reference for the velocity and strain estimations, this procedure compensated for the motion of the heart. The short distance allowed for the use of high frequencies and pulse repetition rates. The system was driven in pulse-echo mode, using electronics developed for the application, and radio frequency (RF) lines were recorded at a pulse repetition rate of 2500 s^-1. The endocardial border was detected using an algorithm based on fuzzy logic with filtration to reduce noise and remove outliers, and the myocardium was divided into four layers. Inside the myocardium, radial tissue velocity as a function of depth was calculated from the recorded RF signals, and the velocity estimates were used to estimate radial strain rate and strain and to track the motion of the myocardial layers. The scope of this paper is technical, giving a detailed description of system design, hardware electronics and algorithms, with examples of processed velocity patterns and myocardial strain curves. The results from this study on a porcine model demonstrate the system's ability to estimate myocardial velocity and strain patterns and to track the motion of the myocardial layers, thereby obtaining detailed information of the regional function of the myocardium.

[Perioperative myocardial ischemia : Current aspects and concepts]

In the future an increasing number of older patients with significant comorbidities will have to undergo major surgical procedures. Perioperative cardiovascular events account for many major complications and even fatalities. While perioperative myocardial infarction (PMI) is a generally well-known and recognized complication, the less severe myocardial injury after non-cardiac surgery (MINS) has not gained widespread scientific attention until recently; however, two large observational trials (VISION 1 and VISION 2) have shown a significantly increased mortality after MINS with even subtle increases in troponin T being associated with an increased risk of death. This review summarizes the current knowledge pertaining to PMI and MINS and proposes a diagnostic and therapeutic framework for optimally guiding patients at risk through the perioperative period.

Recommendations for Institutions Transitioning to High-Sensitivity Troponin Testing: JACC Scientific Expert Panel

High-sensitivity cardiac troponin (hs-cTn) I or T methods have been in use in certain regions for years but are now increasingly globally adopted, including in the United States. Accordingly, inevitable challenges are created for institutions transitioning from conventional cardiac troponin (cTn) assays. hs-cTn assays have higher analytic precision at lower concentrations, yielding greater clinical sensitivity for myocardial injury and allowing accurate recognition of small changes in troponin concentration (rise or fall) within a short time frame. Although much of the knowledge regarding troponin biology that was applicable with older troponin assays still holds true, considerable education regarding the differences between conventional cTn and hs-cTn is needed before medical systems convert to the newer methods. This includes a basic understanding of how hs-cTn testing differs from conventional cTn testing and how it is best deployed in different settings, such as the emergency department and inpatient services. This Expert Panel will review important concepts for institutional transition to hs-cTn methodology, providing recommendations useful for education before implementation.

Comparison of In-Hospital Outcomes of Patients With-Versus-Without Ischemic Cardiomyopathy Undergoing Left Ventricular Assist Device Placement

The objective of this study was to evaluate the impact of heart failure (HF) etiology (ischemic cardiomyopathy [ICM] versus nonischemic cardiomyopathy) on in-hospital outcomes in patients undergoing left ventricular assist device (LVAD) placement using the Nationwide Inpatient Sample database. We identified patients who underwent LVAD placement from 2011 to 2014. The primary end point was the effect of ICM on in-hospital mortality. Secondary end points included periprocedural vascular complications requiring surgery, postoperative myocardial infarction, stroke, and hemorrhage requiring transfusion. We also assessed length of stay and cost of hospitalization. A mixed effects logistic model was used for clinical end points and a linear mixed model was used for cost and length of stay. In 3,511 patients who underwent LVAD placement (23.32% women and 56.23 ± 13.51 years old), the incidence of ICM was 53.5%. After adjusting for patient- and hospital-level characteristics, ICM was not found to influence in-hospital mortality (odds ratio [OR] 0.98, 95% confidence interval [CI] 0.78 to 1.23). ICM was associated with an increased risk in periprocedural hemorrhage requiring transfusion (OR 1.29, 95% CI 1.08 to 1.53), vascular complications requiring surgery (OR 1.58 95% CI 1.10 to 2.28) and postoperative ST-segment myocardial infarction (OR 7.38 95% CI 5.33 to 10.24). In conclusion, ICM did not impact in-hospital mortality in patients who underwent LVAD placement but was associated with increased vascular complications, hemorrhage requiring transfusion, and postoperative myocardial infarction.

Preoperative heart rate and myocardial injury after non-cardiac surgery: results of a predefined secondary analysis of the VISION study

Background

Increased baseline heart rate is associated with cardiovascular risk and all-cause mortality in the general population. We hypothesized that elevated preoperative heart rate increases the risk of myocardial injury after non-cardiac surgery (MINS).

Methods

We performed a secondary analysis of a prospective international cohort study of patients aged ≥45 yr undergoing non-cardiac surgery. Preoperative heart rate was defined as the last measurement before induction of anaesthesia. The sample was divided into deciles by heart rate. Multivariable logistic regression models were used to determine relationships between preoperative heart rate and MINS (determined by serum troponin concentration), myocardial infarction (MI), and death within 30 days of surgery. Separate models were used to test the relationship between these outcomes and predefined binary heart rate thresholds.

Results

Patients with missing outcomes or heart rate data were excluded from respective analyses. Of 15 087 patients, 1197 (7.9%) sustained MINS, 454 of 16 007 patients (2.8%) sustained MI, and 315 of 16 037 patients (2.0%) died. The highest heart rate decile (>96 beats min⁻¹) was independently associated with MINS {odds ratio (OR) 1.48 [1.23–1.77]; P<0.01}, MI (OR 1.71 [1.34–2.18]; P<0.01), and mortality (OR 3.16 [2.45–4.07]; P<0.01). The lowest decile (<60 beats min⁻¹) was independently associated with reduced mortality (OR 0.50 [0.29–0.88]; P=0.02), but not MINS or MI. The predefined binary thresholds were also associated with MINS, but more weakly than the highest heart rate decile.

Conclusions

Preoperative heart rate >96 beats min⁻¹ is associated with MINS, MI, and mortality after non-cardiac surgery. This association persists after accounting for potential confounding factors.

Clinical trial registration

NCT00512109.

Etiology of Acute Coronary Syndrome after Noncardiac Surgery

BACKGROUND

The objective of this investigation was to determine the etiology of perioperative acute coronary syndrome with a particular emphasis on thrombosis versus demand ischemia.

METHODS

In this retrospective cohort study, adult patients were identified who underwent coronary angiography for acute coronary syndrome within 30 days of noncardiac surgery at a major tertiary hospital between January 2008 and July 2015. Angiograms were independently reviewed by two interventional cardiologists who were blinded to clinical data and outcomes. Acute coronary syndrome was classified as ST-elevation myocardial infarction, non-ST-elevation myocardial infarction, or unstable angina; myocardial infarctions were adjudicated as type 1 (plaque rupture), type 2 (demand ischemia), or type 4b (stent thrombosis).

RESULTS

Among 215,077 patients screened, 146 patients were identified who developed acute coronary syndrome: 117 were classified as non-ST-elevation myocardial infarction (80.1%); 21 (14.4%) were classified as ST-elevation myocardial infarction, and 8 (5.5%) were classified as unstable angina. After coronary angiography, most events were adjudicated as demand ischemia (type 2 myocardial infarction, n = 106, 72.6%) compared to acute coronary thrombosis (type 1 myocardial infarction, n = 37, 25.3%) and stent thrombosis (type 4B, n = 3, 2.1%). Absent or only mild, nonobstructive coronary artery disease was found in 39 patients (26.7%). In 14 patients (9.6%), acute coronary syndrome was likely due to stress-induced cardiomyopathy. Aggregate 30-day and 1-yr mortality rates were 7 and 14%, respectively.

CONCLUSIONS

The dominant mechanism of perioperative acute coronary syndrome in our cohort was demand ischemia. A subset of patients had no evidence of obstructive coronary artery disease, but findings were consistent with stress-induced cardiomyopathy.

Pretransplant Resting Heart Rate and Its Association With All-Cause Mortality in Liver Transplant Recipients

BACKGROUND

The importance of heart rate (HR) measurement as a prognostic factor has been recognized in many clinical conditions, such as hypertension, coronary artery disease, or heart failure. Patients with liver cirrhosis tend to have increased resting HR as consequence of hyperdynamic circulation. In the current study, we examined whether pretransplant resting increased HR is associated with overall mortality in cirrhotic patients following liver transplantation (LT).

PATIENTS AND METHODS

We retrospectively collected and analyzed the data of 881 liver recipients who underwent LT surgery between October 2009 and September 2012. Patients were categorized into 3 groups by tertile of resting HR as follows: tertile 1 group, HR ≤ 65 beats per minute (bpm); tertile 2 group, HR 66 to 80 bpm; and tertile 3 group, HR > 80 bpm.

RESULTS

Kaplan-Meier analysis showed that the all-cause mortality rate was significantly different according to tertiles of HR (P = .016, log-rank test). The multivariate Cox regression analysis showed that tertile 3 group was significantly associated with higher risk for all-cause mortality (hazard ratio 1.83, 95% confidence interval, 1.10-3.07; P = .021) compared with tertile 1 group, after adjusting for clinically significant variables in univariate analysis.

CONCLUSIONS

Our results demonstrate that pretransplant resting tachycardia can identify patients at high risk of death in cirrhotic patients following LT, suggesting that further study will be need to clarify relationship between HR burden and sympathetic cardiac neuropathy.

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.

Incidence and predictors of perioperative myocardial infarction in patients undergoing non-cardiac surgery in a tertiary care hospital

Background

The stress in the perioperative period is compounded by unpredictable and un-physiological changes in sympathetic tone, cardiovascular performance, coagulation and inflammatory responses, all of which in turn lead to alterations in plaque morphology predisposing to perioperative myocardial infarction (PMI). PMI has a considerable morbidity and mortality in patients undergoing not only high risk surgery, but also even with minor surgical interventions.

Objective

To study the incidence of PMI and its predictors in patients undergoing non-cardiac surgery in a tertiary care hospital.

Materials and methods

Patients undergoing non-cardiac surgery were included in this prospective single-center observational study. The revised cardiac risk index (RCRI) was used for risk stratification. ECG monitoring was done for all patients. For patients suggestive of acute myocardial ischemia, echocardiography and serum troponin were evaluated. The patient was labeled as having a PMI if there was raised troponin level along with any one evidence of myocardial ischemia (symptoms, ECG changes or imaging results) and in these patients the factors predisposing to PMI were evaluated. All patients in the study were followed up to 30 days.

Results

Of the 525 patients analyzed, 33 patients (6.28%) had a PMI. Twelve out of the 33 (36.36%) PMI patients died within 30 days following surgery. Patients undergoing high risk surgery, smokers and patients with a past history of ischemic heart disease (IHD) were found to be at higher risk of developing PMI. The ASA physical status classification and the RCRI proved to be good predictors of PMI. Most of the PMI events (72.7%) occurred within 48 hours of surgery.

Conclusion

PMI is a dreaded complication associated with a very high mortality. High risk surgery, smoking and past history of ischemic heart disease were independent predictors of PMI. The RCRI is a useful tool in pre-operative risk stratification of patients.

The myocardial protective effect of dexmedetomidine in high-risk patients undergoing aortic vascular surgery

Objective:

The aim of the study was to assess the effect of dexmedetomidine in high-risk patients undergoing aortic vascular surgery.

Design:

A randomized prospective study.

Setting:

Cairo University, Egypt.

Materials and Methods:

The study included 150 patients undergoing aortic vascular surgery.

Intervention:

The patients were classified into two groups (n = 75). Group D: The patients received a loading dose of 1 μg/kg dexmedetomidine over 15 min before induction and maintained as an infusion of 0.3 μg/kg/h to the end of the procedure. Group C: The patients received an equal volume of normal saline. The medication was prepared by the nursing staff and given to anesthetist blindly.

Measurements:

The monitors included the heart rate, mean arterial blood pressure, central venous pressure, electrocardiogram (ECG), serum troponin I level, end-tidal sevoflurane, and total dose of morphine in addition transthoracic echocardiography to the postoperative in cases with elevated serum troponin I level.

Main Results:

The dexmedetomidine decreased heart rate and minimized the changes in blood pressure compared to control group (P < 0.05). Furthermore, it decreased the incidence of myocardial ischemia reflected by troponin I level, ECG changes, and the development of new regional wall motion abnormalities (P < 0.05). Dexmedetomidine decreased the requirement for nitroglycerin and norepinephrine compared to control group (P < 0.05). The incidence of hypotension and bradycardia was significantly higher with dexmedetomidine (P < 0.05).

Conclusion:

The dexmedetomidine is safe and effective in patients undergoing aortic vascular surgery. It decreases the changes in heart rate and blood pressure during the procedures. It provides cardiac protection in high-risk patients reflected by decreasing the incidence of myocardial ischemia and serum level of troponin. The main side effects of dexmedetomidine were hypotension and bradycardia.

Anesthesia for Patients with Concomitant Cardiac and Renal Dysfunction

Renal disease and cardiovascular disease are commonly encountered in the same patient. The dynamic interactions between renal disease and cardiovascular disease have an impact on perioperative management. Renal failure is an independent risk factor for cardiovascular disease and the link between the two disease states remains to be fully elucidated.

Frequency of Increase in Cardiac Troponin Levels After Peripheral Arterial Operations (Carotid Endarterectomy, Abdominal Aorta Procedure, Distal Bypass) and Their Effect on Medical Management

The utility of measuring cardiac troponins (cTn) in asymptomatic patients during the perioperative period has been controversial. In the present substudy of the Cardiac Remote Ischemic Preconditioning Prior to Elective Vascular Surgery Trial (NCT01558596), we hypothesized that surveillance of myocardial injury with cTnI in the perioperative period would lead to initiation or intensification of medical therapies for coronary artery disease. Increases in cTnI ≥0.01 μg/l in the perioperative period were considered clinically significant. Intensification of medical therapy was defined as initiation of aspirin or initiation or increases in the dose of angiotensin-converting-enzyme inhibitors or angiotensin-receptor blockers, statins, or β blockers and was left to the discretion of treating physicians. From June 2011 to April 2015, a total of 185 patients (mean age 68 ± 7 years, 100% men) were enrolled in the trial. A total of 28 patients (15%) had significant increases in cTnI after vascular surgery, and 38 (20.5%) had their medical therapies intensified in the perioperative period. Among patients with increases in cTnI, 11 (39%) had intensification of medical therapy versus 27 patients (17%) with no or smaller increases in cTnI (p = 0.02). Among those patients with ΔcTnI ≥0.01 μg/l, hospital readmissions at 3 to 6 months were 7.6% for the intensification group versus 25% for the no intensification group (p = 0.18). Mortality rate at 6 months was low in both groups (2.6% vs 0%, respectively, p = 0.13). In conclusion, among patients undergoing vascular surgery, perioperative increases in cTn were associated with initiation or intensification of medical therapies for coronary artery disease at the time of discharge.

Postoperative Cardiac Ischemia Detection by Continuous 12-Lead Electrocardiographic Monitoring in Vascular Surgery Patients: A Prospective, Observational Study

OBJECTIVES

Elderly patients undergoing vascular surgery are at major risk for perioperative cardiac complications. The authors investigated continuous electrocardiographic Holter monitoring in a postoperative setting to determine the degree of postoperative ischemic load and its possible associations with perioperative myocardial infarction.

DESIGN

A prospective, observational study.

SETTING

One university hospital.

PARTICIPANTS

The study comprised 51 patients aged 65 years or older undergoing peripheral arterial surgery.

INTERVENTIONS

Continuous electrocardiographic monitoring with a Holter device was started postoperatively and continued for 72 hours or until discharge. Postural changes were recorded using a 3-axis accelerometer. Standard 12-lead electrocardiography, high-sensitive troponin T measurements, and an inquiry of ischemic symptoms were performed 4 times perioperatively.

MEASUREMENTS AND MAIN RESULTS

The primary outcomes were ischemic load (area under the function of ischemic ST-segment deviation and ischemic time) and perioperative myocardial infarction. During 3,262.7 patient-hours of monitoring, 17 patients (33.3%) experienced 608 transient ischemic events, all denoted by ST-segment depression. Of these 17 patients, 5 experienced perioperative myocardial infarction. The mean ischemic load in all patients was 913.2±2,797.3 µV×minute. Ischemic load predicted perioperative myocardial infarction, with an area under receiver operating characteristics curve (95% confidence interval) of 0.87 (0.75-0.99). Ischemic changes occurred most frequently during hours 24 to 60 of monitoring. Ischemia was asymptomatic in 14 of 17 patients (82.4%).

CONCLUSION

Postoperative myocardial ischemia was common in peripheral vascular surgery patients and may progress to perioperative myocardial infarction. Ischemic load was a good predictor of perioperative myocardial infarction. Ambulatory electrocardiographic monitoring solutions for continuous postoperative ischemia detection are warranted in the surgical ward.

Canadian Cardiovascular Society Guidelines on Perioperative Cardiac Risk Assessment and Management for Patients Who Undergo Noncardiac Surgery

The Canadian Cardiovascular Society Guidelines Committee and key Canadian opinion leaders believed there was a need for up to date guidelines that used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system of evidence assessment for patients who undergo noncardiac surgery. Strong recommendations included: 1) measuring brain natriuretic peptide (BNP) or N-terminal fragment of proBNP (NT-proBNP) before surgery to enhance perioperative cardiac risk estimation in patients who are 65 years of age or older, are 45-64 years of age with significant cardiovascular disease, or have a Revised Cardiac Risk Index score ≥ 1; 2) against performing preoperative resting echocardiography, coronary computed tomography angiography, exercise or cardiopulmonary exercise testing, or pharmacological stress echocardiography or radionuclide imaging to enhance perioperative cardiac risk estimation; 3) against the initiation or continuation of acetylsalicylic acid for the prevention of perioperative cardiac events, except in patients with a recent coronary artery stent or who will undergo carotid endarterectomy; 4) against α₂ agonist or β-blocker initiation within 24 hours before surgery; 5) withholding angiotensin-converting enzyme inhibitor and angiotensin II receptor blocker starting 24 hours before surgery; 6) facilitating smoking cessation before surgery; 7) measuring daily troponin for 48 to 72 hours after surgery in patients with an elevated NT-proBNP/BNP measurement before surgery or if there is no NT-proBNP/BNP measurement before surgery, in those who have a Revised Cardiac Risk Index score ≥1, age 45-64 years with significant cardiovascular disease, or age 65 years or older; and 8) initiating of long-term acetylsalicylic acid and statin therapy in patients who suffer myocardial injury/infarction after surgery.

Signal Quality Analysis of Ambulatory Electrocardiograms to Gate False Myocardial Ischemia Alarms

OBJECTIVE

The objective of this study is to propose and validate an alarm gating system for a myocardial ischemia monitoring system that uses ambulatory electrocardiogram. The PeriOperative ISchemic Evaluation study recommended the selective administration of β blockers to patients at risk of cardiac events following noncardiac surgery. Patients at risk are identified by monitoring ST segment deviations in the electrocardiogram (ECG); however, patients are encouraged to ambulate to improve recovery, which deteriorates the signal quality of the ECG leading to false alarms.

METHODS

The proposed alarm gating system computes a signal quality index (SQI) to quantify the ECG signal quality and rejects alarms with a low SQI. The system was validated by artificially contaminating ECG records with motion artifact records obtained from the long-term ST database and MIT-BIH noise stress test database, respectively.

RESULTS

Without alarm gating, the myocardial ischemia monitoring system attained a Precision of 0.31 and a Recall of 0.78. The alarm gating improved the Precision to 0.58 with a reduction of Recall to 0.77.

CONCLUSION

The proposed system successfully gated false alarms with future work exploring the misidentification of fiducial points by myocardial ischemia monitoring systems.

SIGNIFICANCE

The reduction of false alarms due to the proposed system will decrease the incidence of the alarm fatigue condition typically found in clinicians. Alarm fatigue condition was rated as the top patient safety hazard from 2012 to 2015 by the Emergency Care Research Institute.

Role of prophylactic coronary revascularisation in improving cardiovascular outcomes during non-cardiac surgery: A narrative review

Coronary revascularisation has been a topic of debate for over three decades in patients undergoing high-risk non-cardiac surgery. The paradigm shifted from routine coronary angiography toward stress test guided decision-making based on larger randomised trials. However, this paradigm is challenged by relatively newer data where routine coronary angiography and revascularisation is shown to improve perioperative cardiovascular outcomes. We review major studies performed over a long period including more contemporary data with regard to the 2014 American College of Cardiology/American Heart Association as well as 2014 European Society of Cardiology guideline on perioperative cardiovascular evaluation of patients undergoing non-cardiac surgery.

Diagnosing Perioperative Myocardial Infarction in Cardioth oracic and Vascular Surgery

Patients undergoing cardiac and high-risk noncardiac surgery have a high incidence of perioperative myocardial infarction. The early diagnosis of perioperative myocardial injury in these patients is complicated. In the perioperative period, there is a high incidence of nonspecific electrocardiographic changes and cardiac biomarker release. It is becoming increasingly imortant to differentiate myocardial necrosis from nonspecific changes because of the need for early intervention and the poential long term implications of a perioperative myocardial event. Although sensitive and specific assays to assess myoardial damage have been developed, specific thresholds to establish the occurrence a significant perioperative event have not been firmly defined. This review will attempt to outline the current evidence supporting the use of clinical symptoms, electrocardiographic changes, and cardiac biomarkers in the diagnosis of perioperative myocardial infarction and the longerm implication of these findings.

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.

Repeated Episodes of Remote Ischemic Preconditioning for the Prevention of Myocardial Injury in Vascular Surgery

OBJECTIVES

Remote ischemic preconditioning (RIPC) involves the phenomenon whereby transient episodes of limb ischemia induced by cuff inflation provide cardioprotection. The effectiveness of RIPC in vascular surgery is uncertain. This randomized, controlled trial was designed to investigate the potential of two episodes of RIPC to provide myocardial protection in patients undergoing vascular surgery.

DESIGN AND METHODS

Patients undergoing an elective major vascular procedure (open abdominal aortic aneurysm (AAA) repair, endovascular aneurysm repair, and lower-limb bypass grafting) were randomized into RIPC group (n = 42) or control group (n = 43). Remote ischemic preconditioning consisted of three 5-minute cycles of upper limb cuff occlusion with 5-minutes of reperfusion between cycles, both 24 hours and immediately before surgery. Control patients received a similarly timed sham treatment. Cardiac high-sensitivity troponin T (hsTnT) concentration was measured in plasma at 6, 12, 24, and 48 hours post-surgery, and at 72, 96, and 120 hours in patients still in hospital. Perioperative clinical adverse events and readmissions within ∼12 months were recorded.

RESULTS

Myocardial injury was demonstrated perioperatively in 43% of RIPC patients and 49% of controls, as defined by a significant hsTnT elevation. These incidences were statistically equivalent (odds ratio 0.79, 95% confidence interval 0.33-1.85, P = .58). The 48-hour area under the curve for hsTnT change from baseline also revealed no difference (RIPC vs control median: 5.3 vs 7.5 ng/L.h, P = .22). Each group had one type I and one type II myocardial infarction and no difference in complications or readmissions.

CONCLUSIONS

This trial could not confirm that two episodes of RIPC reduce myocardial injury following vascular surgery. Along with other equivocal studies, it appears that RIPC does not induce a clear benefit in vascular surgery.

Frequency of concomitant ischemic heart disease and risk factor analysis for an early postoperative myocardial infarction after elective abdominal aortic aneurysm repair

Purpose

We aimed to see the frequency of concomitant ischemic heart disease (IHD) in Korean patients with abdominal aortic aneurysm (AAA) and to determine risk factors for an early postoperative acute myocardial infarction (PAMI) after elective open or endovascular AAA repair.

Methods

We retrospectively reviewed a database of patients who underwent elective AAA repair over the past 11 years. Patients were classified into 3 groups: control group; group I, medical IHD treatment; group II, invasive IHD treatment. Rates of PAMI and mortality at 30 days were compiled and compared between groups according to the type of AAA repair.

Results

Six hundred two elective repairs of infrarenal or juxtarenal AAAs were enrolled in this study. The patients were classified into control group (n = 398, 66.1%), group I (n = 73, 12.1%) and group II (n = 131, 21.8%). PAMI developed more frequently after open surgical repair (OSR) than after endovascular aneurysm repair (EVAR) (5.4% vs. 1.3%, P = 0.012). In OSR patients (n = 373), PAMI developed 2.1% in control group, 18.0% in group I and 7.1% in group II (P < 0.001). In EVAR group (n = 229), PAMI developed 0.6% in control group, 4.3% in group I and 2.2% in group II (P = 0.211). On the multivariable analysis of risk factors of PAMI, PAMI developed more frequently in patients with positive functional stress test.

Conclusion

The prevalence of concomitant IHD was 34% in Korean AAA patients. The risk of PAMI was significantly higher after OSR compared to EVAR and in patients with IHD compared to control group. Though we found some risk factors for PAMI, these were not applied to postoperative mortality rate.

The second window of desflurane-induced preconditioning is mediated by STAT3: role of Pim-1 kinase

BACKGROUND

Late ischemic preconditioning is mediated via nuclear transcription factor signal transducer and activator of transcription 3 (STAT3). Pim-1 kinase reduces infarct size in cardiomyocytes and is regulated by STAT3. We tested the hypothesis that late desflurane-induced preconditioning (DES-SWOP) is mediated via STAT3 and Pim-1.

METHODS

After institutional approval, pentobarbital-anesthetized male C57BL/6 mice were subjected to 45 min coronary artery occlusion (CAO) and 3 h reperfusion. Control animals received no additional intervention. Desflurane was administered 48 h before CAO either alone or in combination with the janus kinase/STAT3 inhibitor AG-490 (40 μg/g i.p., 20 min before desflurane administration) or the Pim-1 kinase inhibitor II (PIM-Inh.II, 10 μg/g i.p., 15 min before CAO). Infarct size (IS) and area at risk were determined with triphenyltetrazolium chloride and Evans blue, respectively. Additionally, cytosolic and nuclear fractions were separated at two different time points and expression of STAT3, phospho-STAT3(Ser727) , phospho-STAT3(Tyr705) , Pim-1, Bad and phospho-Bad(Ser112) were determined by Western Blot analysis. Data were analyzed with one-way or two-way ANOVA and post hoc Duncan test and are presented as mean ± SEM.

RESULTS

IS was 47 ± 2% (n = 7-8 per group) in control animals (CON). DES-SWOP reduced myocardial infarct size to 23 ± 4%* (*P < 0.05 vs. CON). AG-490 alone did not affect myocardial infarct size (44 ± 7%), but abolished DES-SWOP (44 ± 4%). Blockade of Pim-1 did not affect the protection by DES-SWOP (34 ± 4%*). Desflurane reduced cytosolic content and enhanced nuclear content of phospho-STAT(S) (er727) . After 48 h, desflurane enhanced Pim-1 activity, whereas Pim-1 expression remained unchanged.

CONCLUSION

These data suggest that DES-SWOP is mediated by activation and nuclear translocation of STAT3. The impact of Pim-1 in DES-SWOP signaling remains unclear.

Kinetics of Highly Sensitive Troponin T after Cardiac Surgery

Perioperative myocardial infarction (PMI) confers a considerable risk in cardiac surgery settings; finding the ideal biomarker seems to be an ideal goal. Our aim was to assess the diagnostic accuracy of highly sensitive troponin T (hsTnT) in cardiac surgery settings and to define a diagnostic level for PMI diagnosis. This was a single-center prospective observational study analyzing data from all patients who underwent cardiac surgeries. The primary outcome was the diagnosis of PMI through a specific level. The secondary outcome measures were the lengths of mechanical ventilation (LOV), stay in the intensive care unit (LOSICU), and hospitalization. Based on the third universal definition of PMI, patients were divided into two groups: no PMI (Group I) and PMI (Group II). Data from 413 patients were analyzed. Nine patients fulfilled the diagnostic criteria of PMI, while 41 patients were identified with a 5-fold increase in their CK-MB (≥120 U/L). Using ROC analysis, a hsTnT level of 3,466 ng/L or above showed 90% sensitivity and 90% specificity for the diagnosis of PMI. Secondary outcome measures in patients with PMI were significantly prolonged. In conclusion, the hsTnT levels detected here paralleled those of CK-MB and a cut-off level of 3466 ng/L could be diagnostic of PMI.

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.

Continuous monitoring of regional function by a miniaturized ultrasound transducer allows early quantification of low-grade myocardial ischemia

BACKGROUND

Sensitive methods for the early detection of myocardial dysfunction are still needed, as ischemia is a leading cause of decreased ventricular function during and after heart surgery. The aim of this study was to test the hypothesis that low-grade ischemia could be detected quantitatively by a miniaturized epicardial ultrasound transducer (Ø = 3 mm), allowing continuous monitoring.

METHODS

In 10 pigs, transducers were positioned in the left anterior descending and circumflex coronary artery areas. Left ventricular pressure was obtained by a micromanometer. The left internal mammary artery was grafted to the left anterior descending coronary artery, which was occluded proximal to the anastomosis. Left internal mammary artery flow was stepwise reduced by 25%, 50%, and 75% for 18 min each. From the transducers, M-mode traces were obtained, allowing continuous tissue velocity traces and displacement measurements. Regional work was assessed as left ventricular pressure-displacement loop area. Tissue lactate measured from intramyocardial microdialysis was used as reference method to detect ischemia.

RESULTS

All steps of coronary flow reduction demonstrated reduced peak systolic velocity (P < .05) and regional work (P < .01).The decreases in peak systolic velocity and regional work were closely related to the degree of ischemia, demonstrated by their correlations with lactate (R = -0.74, P < .01, and R = -0.64, P < .01, respectively). The circumflex coronary artery area was not affected by any of the interventions.

CONCLUSIONS

The epicardially attached miniaturized ultrasound transducer allowed the precise detection of different levels of coronary flow reduction. The results also showed a quantitative and linear relationship among coronary flow, ischemia, and myocardial function. Thus, the ultrasound transducer has the potential to improve the monitoring of myocardial ischemia and to detect graft failure during and after heart surgery.

Perioperative clinical variables and long-term survival following vascular surgery

Cardiovascular disease is the leading cause of death in patients with peripheral arterial disease (PAD). Coronary artery disease (CAD) is highly prevalent, and often times coexist, in patients with PAD. The management of patients with PAD that requires a high-risk vascular surgical procedure for intermittent claudication, critical limb ischemia or expanding abdominal aortic aneurysm requires risk stratification with the revised cardiac risk index, optimization of medical therapies, and limited use of cardiac imaging prior to surgery. Preventive revascularization in patients with stable CAD, with the sole intention to mitigate the risk of cardiac complications in the peri-operative period, is not effective and may be associated with significant bleeding and thrombotic risks, in particular if stents are used. A strategy of universal use of cardiac troponins in the perioperative period for active surveillance of myocardial ischemia may be more reasonable and cost-effective than the current standard of care of widespread use of cardiac imaging prior to high-risk surgery. An elevated cardiac troponin after vascular surgery is predictive of long-term mortality risk. Medical therapies such as aspirin and statins are recommended for patients with post-operative myocardial ischemia. Ongoing trials are assessing the role of novel anticoagulants. Additional research is needed to define the role of cardiac imaging and invasive angiography in this population.

Use of ivabradine and atorvastatin in emergent orthopedic lower limb surgery and computed tomography coronary plaque imaging and novel biomarkers of cardiovascular stress and lipid metabolism for the study and prevention of perioperative myocardial infarction: study protocol for a randomized controlled trial

Background

The incidence of perioperative myocardial infarction (PMI) globally is known to be around 2 to 3% and can prolong hospitalization, increased morbidity and mortality. Little is known about the pathophysiology and risk factors for PMI. We investigate the presence of elevated novel cardiac markers and preoperative coronary artery plaque through contemporary laboratory techniques to determine the correlation with PMI, as well as studying ivabradine and atorvastatin as protective pharmacotherapies against PMI in the context of orthopedic surgery.

Methods/Design

We aim to enroll 200 patients aged above 60 years who suffer from neck of femur fracture requiring surgery. Patients will be randomized to four arms (no study drugs, atorvastatin only, ivabradine only and ivabradine and atorvastatin). Our primary outcome is incidence of PMI. All patients will receive an electrocardiogram, cardiac echocardiography, measurement of novel cardiac biomarkers and computed tomography (CT) coronary angiography. A telephone interview post discharge will be conducted at 30 days, 60 days and 1 year.

Discussion

We postulate that ivabradine and atorvastatin will reduce the rate and magnitude of PMI following surgery by reducing heart rate and attenuating catecholamine-induced tachycardia postoperatively. Secondly, we postulate that postoperative reduction in heart rate and catecholamine-induced tachycardia with ivabradine will correlate with a reduction in cardiovascular novel biomarkers which will reduce atrial stretch and postoperative incidence of arrhythmia. We aim to demonstrate that treatment with ivabradine and atorvastatin will cause a reduction in the incidence and magnitude of PMI, the benefit of which is derived primarily in patients with greater atherosclerotic burden as measured by higher CT coronary calcium scores.

Trial registration

This study protocol has been listed in the Australia New Zealand Clinical Trial Registry (registration number: ACTRN12612000340831) on 23 March 2012.