Perioperative myocardial infarction

Preoperative biomarker evaluation for the prediction of cardiovascular events after major vascular surgery

OBJECTIVE

The cause of perioperative myocardial infarction (PMI) is postulated to involve hemodynamic stress or coronary plaque destabilization. We aimed to evaluate perioperative factors in patients with peripheral artery disease (PAD) undergoing major vascular surgery to determine the likely mechanisms and predictors of PMI.

METHODS

This was a prospective cohort study of 133 patients undergoing major vascular surgery including open abdominal aortic aneurysm (AAA) repair (n = 40) and major suprainguinal or infrainguinal arterial bypasses (non-AAA; n = 93). Preoperative assessment with history, physical examination, and peripheral artery tonometry was performed in addition to plasma sampling of biomarkers associated with inflammation and coronary plaque instability. The primary outcome was occurrence of a 30-day cardiovascular event (CVE; composite of PMI [troponin I elevation >99th percentile reference of ≥0.1 μg/L], stroke, or death).

RESULTS

Of 133 patients, 36 patients (27%) developed a 30-day CVE after vascular surgery, and all were PMI. Patients with 30-day CVE were older (75 ± 8 years vs 69 ± 10 years, mean ± standard deviation; P = .001), had higher prevalence of hypertension (94% vs 79%; P = .01) and preoperative beta-blocker therapy (50% vs 29%; P = .02), and had longer duration of surgery (5.1 ± 1.8 hours vs 4.0 ± 1.1 hours; P < .0001). Significant elevations in cystatin C, N-terminal pro-B-type natriuretic peptide (NT-proBNP), troponin I, high-sensitivity troponin T, matrix metalloproteinase 3, and osteoprotegerin occurred in those who developed 30-day CVE (all P < .05). Multivariate binary logistic regression identified AAA surgery and log-transformed NT-proBNP to be independent preoperative predictors of 30-day CVE (area under the receiver operating characteristic curve = 0.81).

CONCLUSIONS

In patients with peripheral artery disease undergoing major vascular surgery, the likely mechanism of PMI appears to be the hemodynamic stress related to the type and duration of surgery. NT-proBNP was a useful independent predictor of CVE and thus may serve as an important biomarker of cardiovascular fitness for surgery.

Assessing Pancreas Transplant Candidate Cardiac Disease: Preoperative Protocol Development at a Rapidly Growing Transplant Program

Pancreas transplant rates, despite improving outcomes, have decreased over the past two decades. This is due, in part, to ageing, increasingly co-morbid pancreas transplant candidates. There is a paucity of published data regarding coronary artery disease (CAD) in this population. To inform peri-operative management strategies, we sought to understand the frequency of CAD among recipients of pancreas transplants at our center. Informed by these data, we sought to develop a standard protocol for evaluation. A retrospective review of pancreas transplants (solitary pancreas and simultaneous pancreas-kidney) was undertaken at the University of Maryland. Transplant outcomes and frequency of cardiac disease were analyzed. Current data were compared with historic controls. Over the study period, 59 patients underwent pancreas transplantation. Coronary architecture was assessed in 38 patients (64.4%). Discrete evidence of CAD was present in 28 of 39 patients (71.7%). All pancreas candidates (n = 21) who underwent left heart catheterization (LHC) demonstrated CAD (100%). No patients experienced myocardial infarction (MI) and no deaths resulted from cardiac disease in the early post-transplant period. Pancreas transplant candidates are at high risk for CAD. At a center in which pancreas transplant rates are increasing, a rigorous cardiac work up revealed that 71.7% of assessed recipients had CAD. Although asymptomatic, 6.8% required coronary artery bypass graft (CABG). Despite increasing age and co-morbid status, pancreas transplant recipients can enjoy excellent results if protocolized preoperative testing is used.

Assessment and Treatment of Patients With Type 2 Myocardial Infarction and Acute Nonischemic Myocardial Injury

Although coronary thrombus overlying a disrupted atherosclerotic plaque has long been considered the hallmark and the primary therapeutic target for acute myocardial infarction (MI), multiple other mechanisms are now known to cause or contribute to MI. It is further recognized that an MI is just one of many types of acute myocardial injury. The Fourth Universal Definition of Myocardial Infarction provides a taxonomy for acute myocardial injury, including 5 subtypes of MI and nonischemic myocardial injury. The diagnosis of MI is reserved for patients with myocardial ischemia as the cause of myocardial injury, whether attributable to acute atherothrombosis (type 1 MI) or supply/demand mismatch without acute atherothrombosis (type 2 MI). Myocardial injury in the absence of ischemia is categorized as acute or chronic nonischemic myocardial injury. However, optimal evaluation and treatment strategies for these etiologically distinct diagnoses have yet to be defined. Herein, we review the epidemiology, risk factor associations, and diagnostic tools that may assist in differentiating between nonischemic myocardial injury, type 1 MI, and type 2 MI. We identify limitations, review new research, and propose a framework for the diagnostic and therapeutic approach for patients who have suspected MI or other causes of myocardial injury.

A Prospective International Multicentre Cohort Study of Intraoperative Heart Rate and Systolic Blood Pressure and Myocardial Injury After Noncardiac Surgery: Results of the VISION Study

BACKGROUND

The association between intraoperative cardiovascular changes and perioperative myocardial injury has chiefly focused on hypotension during noncardiac surgery. However, the relative influence of blood pressure and heart rate (HR) remains unclear. We investigated both individual and codependent relationships among intraoperative HR, systolic blood pressure (SBP), and myocardial injury after noncardiac surgery (MINS).

METHODS

Secondary analysis of the Vascular Events in Noncardiac Surgery Cohort Evaluation (VISION) study, a prospective international cohort study of noncardiac surgical patients. Multivariable logistic regression analysis tested for associations between intraoperative HR and/or SBP and MINS, defined by an elevated serum troponin T adjudicated as due to an ischemic etiology, within 30 days after surgery. Predefined thresholds for intraoperative HR and SBP were: maximum HR >100 beats or minimum HR <55 beats per minute (bpm); maximum SBP >160 mm Hg or minimum SBP <100 mm Hg. Secondary outcomes were myocardial infarction and mortality within 30 days after surgery.

RESULTS

After excluding missing data, 1197 of 15,109 patients (7.9%) sustained MINS, 454 of 16,031 (2.8%) sustained myocardial infarction, and 315 of 16,061 patients (2.0%) died within 30 days after surgery. Maximum intraoperative HR >100 bpm was associated with MINS (odds ratio [OR], 1.27 [1.07-1.50]; P < .01), myocardial infarction (OR, 1.34 [1.05-1.70]; P = .02), and mortality (OR, 2.65 [2.06-3.41]; P < .01). Minimum SBP <100 mm Hg was associated with MINS (OR, 1.21 [1.05-1.39]; P = .01) and mortality (OR, 1.81 [1.39-2.37]; P < .01), but not myocardial infarction (OR, 1.21 [0.98-1.49]; P = .07). Maximum SBP >160 mm Hg was associated with MINS (OR, 1.16 [1.01-1.34]; P = .04) and myocardial infarction (OR, 1.34 [1.09-1.64]; P = .01) but, paradoxically, reduced mortality (OR, 0.76 [0.58-0.99]; P = .04). Minimum HR <55 bpm was associated with reduced MINS (OR, 0.70 [0.59-0.82]; P < .01), myocardial infarction (OR, 0.75 [0.58-0.97]; P = .03), and mortality (OR, 0.58 [0.41-0.81]; P < .01). Minimum SBP <100 mm Hg with maximum HR >100 bpm was more strongly associated with MINS (OR, 1.42 [1.15-1.76]; P < .01) compared with minimum SBP <100 mm Hg alone (OR, 1.20 [1.03-1.40]; P = .02).

CONCLUSIONS

Intraoperative tachycardia and hypotension are associated with MINS. Further interventional research targeting HR/blood pressure is needed to define the optimum strategy to reduce MINS.

[In-hospital Myocardial Infarction: Scale of the Problem]

All cases of acute myocardial infarction (AMI) can be divided into outpatient-onset AMI and in-hospital-onset AMI depending on the place and circumstances of their development. In this review we consider the problem of in-hospital AMI. Special attention is paid to specific features of its clinical manifestations and the scale of the clinical problem. Possible causes of difficulties in the diagnosis and treatment of this condition are presented in comparison with those in patients with outpatient-onset AMI.

Prevalence and risk factors of subclinical coronary artery disease in patients undergoing carotid endarterectomy: a retrospective cohort study

BACKGROUND

Coronary artery disease (CAD) is closely associated with carotid artery stenosis in the context of systemic arteriosclerosis, and it is a known perioperative risk factor for carotid endarterectomy (CEA). We aimed to evaluate the prevalence and risk factors of subclinical CAD in patients without known CAD undergoing CEA.

METHODS

This was a single-center, retrospective, observational study conducted between January 2013 and December 2016. Among the patients scheduled for elective CEA, 69 with no medical history of CAD and no clinical symptoms (mean age, 76.4±7.8 years; 71.0% men) underwent coronary computed tomography (CT). Coronary angiography (CAG) and subsequent fractional flow reserve (FFR) estimation were performed if necessary. Subclinical CAD was defined as newly found significant coronary lesions after coronary CT screening. Significant coronary lesions were defined as lesions that showed total or subtotal occlusion on coronary CT, had ≥75% stenosis on CAG, or had FFR≤0.80 in major coronary arteries.

RESULTS

The prevalence of subclinical CAD was 17.4% (12 of 69 patients). Among the patient characteristics assessed, only high-density lipoprotein cholesterol (HDL-C) levels were significantly different between patients with and those without subclinical CAD (45.8±10.1 vs. 59.7±16.7 mg/dL, P=0.0072). A multivariate analysis revealed that low HDL-C levels were independent risk factors for subclinical CAD after adjusting for possible confounders (adjusted odds ratio: 0.91, 95% confidence interval: 0.84-0.98, P=0.0099).

CONCLUSIONS

Subclinical CAD is a common finding and is associated with low HDL-C in patients without known CAD undergoing CEA.

Postoperative Management in Patients with Pheochromocytoma and Paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare catecholamine-secreting neuroendocrine tumors of the adrenal medulla and sympathetic/parasympathetic ganglion cells, respectively. Excessive release of catecholamines leads to episodic symptoms and signs of PPGL, which include hypertension, headache, palpitations, and diaphoresis. Intraoperatively, large amounts of catecholamines are released into the bloodstream through handling and manipulation of the tumor(s). In contrast, there could also be an abrupt decline in catecholamine levels after tumor resection. Because of such binary manifestations of PPGL, patients may develop perplexing and substantially devastating cardiovascular complications during the perioperative period. These complications include hypertension, hypotension, arrhythmias, myocardial infarction, heart failure, and cerebrovascular accident. Other complications seen in the postoperative period include fever, hypoglycemia, cortisol deficiency, urinary retention, etc. In the interest of safe patient care, such emergencies require precise diagnosis and treatment. Surgeons, anesthesiologists, and intensivists must be aware of the clinical manifestations and complications associated with a sudden increase or decrease in catecholamine levels and should work closely together to be able to provide appropriate management to minimize morbidity and mortality associated with PPGLs.

Perioperative myocardial injury in revascularized coronary patients who undergo noncardiac surgery

BACKGROUND

Whether high-sensitivity cardiac troponin elevation during the perioperative period is associated with poor clinical outcome in revascularized coronary patients who undergo noncardiac surgery remains unclear. We investigated the effects of perioperative troponin elevation on the long-term clinical outcomes of patients with a history of coronary revascularization.

METHODS

We analyzed patients whose pre- or postoperative high-sensitivity cardiac troponin I (hs-cTnI) assay results were available. Patients were divided into two groups according to hs-cTnI levels. The patient groups were analyzed separately according to whether hs-cTnI was assessed preoperatively or postoperatively. The primary outcome was all-cause death during the follow-up period.

RESULTS

Median follow-up duration was 25 months (interquartile range 11-50). In the propensity-matched analysis, the risk of all-cause death during follow-up was higher in the group with elevated hs-cTnI group than in the normal group (12.7% vs 6.3%; hazard ratio [HR], 2.67; 95% confidential interval [CI], 1.04-6.82; p = 0.04). In the propensity-matched analysis of preoperative hs-cTnI levels, we found no significant difference between the groups in the rate of all-cause death (12.9% vs. 11.9%; HR, 1.06; 95% CI, 0.45-2.50; p = 0.89). In the postoperative propensity-matched analysis, all-cause death was higher in patients with elevated hs-cTnI than in those with normal levels (14.9% vs. 5.9%; HR, 2.80; 95% CI, 1.01-7.77; p = 0.048).

CONCLUSION

In revascularized coronary patients who underwent noncardiac surgery, postoperative (but not preoperative) hs-cTnI elevation was associated with all-cause death during follow-up. Larger datasets are needed to support this finding.

Peri-operative copeptin concentrations and their association with myocardial injury after vascular surgery: A prospective observational cohort study

BACKGROUND

Copeptin levels in conjunction with cardiac troponin may be used to rule out early myocardial infarction in patients presenting with chest pain. Raised pre-operative copeptin has been shown to be associated with postoperative cardiac events. However, very little is known about the peri-operative time course of copeptin or the feasibility of very early postoperative copeptin measurement to diagnose or rule-out myocardial injury.

OBJECTIVES

In this preparatory analysis for a larger trial, we sought to examine the time course of peri-operative copeptin and identify the time at which concentrations returned to pre-operative levels. Second, in an explorative analysis, we sought to examine the association of copeptin in general and at various time points with myocardial injury occurring within the first 48 h.

DESIGN

Preparatory analysis of a prospective, observational cohort study.

SETTING

Single university centre from February to July 2016.

PATIENTS

A total of 30 consecutive adults undergoing vascular surgery.

INTERVENTION

Serial peri-operative copeptin measurements.

MAIN OUTCOME MEASURE

We measured copeptin concentrations before and immediately after surgery (0 h), then at 2, 4, 6 and 8 h after surgery and on the first and second postoperative day. Postoperative concentrations were compared with pre-operative levels with a Wilcoxon signed-rank test. Second, we explored an association between postoperative copeptin concentrations and myocardial injury by the second postoperative day. Myocardial injury was defined as a 5 ng l increase between pre-operative and postoperative high-sensitivity cardiac troponin T with an absolute peak of at least 20 ng l.

RESULTS

Immediate postoperative copeptin concentrations (median [interquartile range]) increased nearly eight-fold from pre-operative values (8.5 [3.6 to 13.8] to 64.75 pmol l [29.6 to 258.7]; P < 0.001). Copeptin concentrations remained elevated until returning to baseline on the second postoperative day. Postoperative copeptin was significantly higher in patients experiencing myocardial injury than in those who did not (P = 0.02). The earliest most promising single time point for diagnosis may be immediately after surgery (0 h). The receiver-operating characteristics curve for immediate postoperative copeptin and myocardial injury by the second postoperative day was 0.743 (95% confidence interval 0.560 to 0.926).

CONCLUSION

Copeptin concentrations are greatly increased after vascular surgery and remain so until the 2nd postoperative day. Postoperative copeptin concentrations appear to be higher in patients who go on to exhibit myocardial injury. Immediate postoperative copeptin concentrations show promise for eliminating or identifying those at risk of myocardial injury.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02687776, Mauermann/Lurati Buse.

Medical therapy for atherosclerotic cardiovascular disease in patients with myocardial injury after non-cardiac surgery

BACKGROUND

Myocardial injury after non-cardiac surgery (MINS) is a common post-operative cardiovascular complication and is associated with short and long-term mortality. The objective of this study was to describe the contemporary management of patients with and without MINS after total joint and spine orthopedic surgery at a large urban health system in the United States.

METHODS

Adults admitted for total joint and major spine surgery from January 2013 through December 2015 with ≥1 cardiac troponin (cTn) measurement during their hospitalization were identified. MINS was defined by a peak cTn above the 99th percentile of the upper reference limit. Demographics, medical comorbidities, and admission and discharge medications were reviewed for all patients.

RESULTS

A total of 2561 patients underwent 2798 orthopedic surgeries, and 236 cases of MINS were identified. Patients with MINS were older (71.9 ± 10.9 vs. 67.0 ± 10.0, p < 0.001) and more likely to have cardiovascular risk factors, including hypertension, chronic kidney disease, prior stroke, coronary artery disease, prior MI, and a history of heart failure. Among patients with MINS, only 112 (47.5%) were discharged on a combination of aspirin and statin. Patients with MINS were more likely to be prescribed a statin (154 [65.3%] vs. 1463 [57.1%], p = 0.018), beta-blocker (147 [62.3%] vs. 1194 [46.6%], p < 0.001), and oral anticoagulation (65 [27.5%] vs. 436 [17.0%], p < 0.001) than patients without MINS.

CONCLUSIONS

The proportion of patients with MINS who were prescribed medical therapy for atherosclerotic cardiovascular disease was low. Additional efforts to determine optimal management of MINS are warranted.

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.

Lipid lowering in dialysis patients with cardiovascular disease who are awaiting kidney transplantation

Dyslipidemias are highly prevalent in chronic kidney disease, end-stage renal disease, and kidney transplant patients. These dyslipidemias are associated with high cardiovascular risk and mortality. Many clinical trials have shown that statin therapy can significantly reduce adverse cardiovascular events in chronic kidney disease patients and kidney transplant recipients. However, three major trials did not show a benefit of statin therapy in end-stage renal disease patients on dialysis. Major guidelines either recommend against the use of statins in patients on dialysis or provide no recommendations about statin use for this complex patient population. As a result, we suspect many patients on dialysis are not on statins, even if they have known atherosclerotic cardiovascular disease. When these patients receive kidney transplants, the risk of adverse cardiovascular events increases in the peri-operative period. Although there are no randomized clinical trials looking at statin use in these patients, we suggest that statin use be considered in patients with a history of atherosclerotic cardiovascular disease, to potentially minimize peri-operative cardiovascular complications. We also recommend further research to determine whether statin therapy in dialysis patients awaiting kidney transplant is associated with better survival.

Causes and prevention of postoperative myocardial injury

Over the past few years non-cardiac surgery has been recognised as a serious circulatory stress test which may trigger cardiovascular events such as myocardial infarction, in particular in patients at high risk. Detection of these postoperative cardiovascular events is difficult as clinical symptoms often go unnoticed. To improve detection, guidelines advise to perform routine postoperative assessment of cardiac troponin. Troponin elevation - or postoperative myocardial injury - can be caused by myocardial infarction. However, also non-coronary causes, such as cardiac arrhythmias, sepsis and pulmonary embolism, may play a role in a considerable number of patients with postoperative myocardial injury. It is crucial to acquire more knowledge about the underlying mechanisms of postoperative myocardial injury because effective prevention and treatment options are lacking. Preoperative administration of beta-blockers, aspirin, statins, clonidine, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, and preoperative revascularisation have all been investigated as preventive options. Of these, only statins should be considered as the initiation or reload of statins may reduce the risk of postoperative myocardial injury. There is also not enough evidence for intraoperative measures such blood pressure optimisation or intensified medical therapy once patients have developed postoperative myocardial injury. Given the impact, better preoperative identification of patients at risk of postoperative myocardial injury, for example using preoperatively measured biomarkers, would be helpful to improve cardiac optimisation.

Cardiac vagal dysfunction and myocardial injury after non-cardiac surgery: a planned secondary analysis of the measurement of Exercise Tolerance before surgery study

Background

The aetiology of perioperative myocardial injury is poorly understood and not clearly linked to pre-existing cardiovascular disease. We hypothesised that loss of cardioprotective vagal tone [defined by impaired heart rate recovery ≤12 beats min⁻¹ (HRR ≤12) 1 min after cessation of preoperative cardiopulmonary exercise testing] was associated with perioperative myocardial injury.

Methods

We conducted a pre-defined, secondary analysis of a multi-centre prospective cohort study of preoperative cardiopulmonary exercise testing. Participants were aged ≥40 yr undergoing non-cardiac surgery. The exposure was impaired HRR (HRR≤12). The primary outcome was postoperative myocardial injury, defined by serum troponin concentration within 72 h after surgery. The analysis accounted for established markers of cardiac risk [Revised Cardiac Risk Index (RCRI), N-terminal pro-brain natriuretic peptide (NT pro-BNP)].

Results

A total of 1326 participants were included [mean age (standard deviation), 64 (10) yr], of whom 816 (61.5%) were male. HRR≤12 occurred in 548 patients (41.3%). Myocardial injury was more frequent amongst patients with HRR≤12 [85/548 (15.5%) vs HRR>12: 83/778 (10.7%); odds ratio (OR), 1.50 (1.08–2.08); P=0.016, adjusted for RCRI). HRR declined progressively in patients with increasing numbers of RCRI factors. Patients with ≥3 RCRI factors were more likely to have HRR≤12 [26/36 (72.2%) vs 0 factors: 167/419 (39.9%); OR, 3.92 (1.84–8.34); P<0.001]. NT pro-BNP greater than a standard prognostic threshold (>300 pg ml⁻¹) was more frequent in patients with HRR≤12 [96/529 (18.1%) vs HRR>12 59/745 (7.9%); OR, 2.58 (1.82–3.64); P<0.001].

Conclusions

Impaired HRR is associated with an increased risk of perioperative cardiac injury. These data suggest a mechanistic role for cardiac vagal dysfunction in promoting perioperative myocardial injury.

Acute and Subacute Triggers of Cardiovascular Events

Inability to predict short-term cardiovascular (CV) events and take immediate preemptive actions has long been the Achilles heel of cardiology. However, certain triggers of these events have come to light. Although these triggers are nonspecific and are part of normal life, studying their temporal relationship with the onset of CV events provides an opportunity to alert high-risk atherosclerotic patients who may be most vulnerable to such triggers, the "vulnerable patient". Herein, we review the literature and shed light on the epidemiology and underlying pathophysiology of different triggers. We describe that certain adrenergic triggers can precipitate a CV event within minutes or hours; whereas triggers that elicit an immune or inflammatory response such as infections may tip an asymptomatic "vulnerable patient" to become symptomatic days and weeks later. In conclusion, healthcare providers should counsel high-risk CV patients (e.g., in secondary prevention clinics or those with coronary artery Calcium >75th percentile) on the topic, advise them to avoid such triggers, take protective measures once exposed, and seek emergency care immediately after becoming symptomatic after such triggers. Furthermore, clinical trials targeting triggers (prevention or intervention) are needed.

Effects of Ischemic Preconditioning on Abdominal Aortic Aneurysm Repair: A Systematic Review and Meta-analysis

BACKGROUND

Ischemic preconditioning is an innate mechanism of cytoprotection against ischemia, with potential for end-organ protection. The primary goal of this study was to systematically review the literature to determine the effect of ischemic preconditioning on outcomes after open and endovascular abdominal aortic aneurysm (AAA) repair.

METHODS

The methodology followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. We included randomized clinical trials that evaluated the effect of remote ischemic preconditioning (RIPC) in reducing morbidity and mortality in patients undergoing open or endovascular AAA repair surgery. The primary outcomes were death, myocardial infarction, and renal impairment. Outcomes were addressed separately for open AAA repair and endovascular AAA repair (EVAR). Data were collected on patient characteristics, methodology, and preconditioning protocol for each trial.

RESULTS

Nine trials of ischemic preconditioning in aortic aneurysm surgery were included with a total of 599 patients; 336 patients were included in the open AAA repair meta-analysis, and 263 patients were included in the EVAR meta-analysis. For both open and endovascular repairs, ischemic preconditioning did not have a significant effect on death, myocardial infarction, or renal impairment requiring dialysis.

CONCLUSIONS

The randomized clinical trials investigating the effect of ischemic preconditioning on outcomes after open and endovascular AAA repair that have been completed to date have not been adequately powered to evaluate improvements in patient-important outcomes. The evidence is insufficient to support the use of ischemic preconditioning for AAA repair in clinical practice. The variability in treatment effect across studies may be explained by clinical and methodological heterogeneity.

Periprocedural Stroke and Myocardial Infarction as Risks for Long-Term Mortality in CREST

BACKGROUND

The Carotid Revascularization Endarterectomy versus Stenting Trial (CREST) previously reported increased mortality in patients who sustained a periprocedural stroke or cardiac event (myocardial infarction [MI] or biomarker only) in follow-up to 4 years. We now extend these observations to 10 years.

METHODS AND RESULTS

CREST is a randomized controlled trial designed to compare the outcomes of carotid stenting versus carotid endarterectomy. Proportional hazards models were used to assess the association between mortality and periprocedural stroke, MI, or biomarker-only events. For 10-year follow-up, patients with periprocedural stroke were at 1.74× the risk of death compared with those without stroke (adjusted hazard ratio [HR]=1.74; 95% CI, 1.21-2.50; P<0.003). This increased risk was driven by increased early (between 0 and 90 days) mortality (adjusted HR=14.41; 95% CI, 5.33-38.94; P<0.0001), with no significant increase in late (between 91 days and 10 years) mortality (adjusted HR=1.40; 95% CI, 0.93-2.10; P=0.11). Patients with a protocol MI were at 3.61× increased risk of death compared with those without MI (adjusted HR=3.61; 95% CI, 2.28-5.73; P<0.0001), with an increased hazard both early (adjusted HR=8.20; 95% CI, 1.86-36.2; P=0.006) and late (adjusted HR=3.40; 95% CI, 2.09-5.53; P<0.0001). Patients with a biomarker-only event were at 2.04× increased risk overall (adjusted HR=2.04; 95% CI, 1.09-3.84; P=0.03) than those without MI, with an increased early hazard (adjusted HR=8.44; 95% CI, 1.09-65.5; P=0.04) and a suggestive but nonsignificant association toward higher 91-day to 10-year risk (1.88; 95% CI, 0.97-3.64; P=0.062) contributing to the increased risk.

CONCLUSIONS

In the CREST trial, patients with periprocedural events demonstrate a substantial increase in future mortality to 10 years. For stroke, this risk is largely confined to an early time frame while periprocedural MI or biomarker-only events confer a continuous increased mortality for 10 years. Strategies to reduce periprocedural events and to optimize the evaluation and management of patients with cardiac events should be considered in efforts to reduce not only early but also long-term mortality.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov . Unique identifier: NCT00004732.

Two-way Interaction Effects of Perioperative Complications on 30-Day Mortality in General Surgery

BACKGROUND

Multiple perioperative complications increase mortality risk, and certain complications synergistically increase this risk to a greater degree than might be expected if the complications were independent, but these effects are not well established.

METHODS

This is a retrospective cohort study of 422,827 intraabdominal general surgery patients (American College of Surgeons National Surgical Quality Improvement Program 2005-2011). Eight complications were evaluated: acute respiratory failure (ARF), acute kidney injury (AKI), sepsis/septic shock, stroke, cardiac arrest (CA), myocardial infarction (MI), deep vein thrombosis/pulmonary embolus, and transfusion. Each combination of two complications (28 total) was modeled using a Cox model for 30-day mortality, with adjustment for preoperative comorbidities and risk factors. Additive interaction was determined with the relative excess risk due to interaction (RERI). A positive RERI indicates that the mortality risk with both complications is greater than the sum of the individual mortality risks. Bonferroni correction was applied (α = 0.05/28 = 0.0018).

RESULTS

Seven combinations demonstrated positive interaction: sepsis-CA (RERI 88.1; p < 0.0001), ARF-AKI (RERI 50.5; p < 0.0001), AKI-sepsis (RERI 33.9; p < 0.0001), sepsis-stroke (RERI 33.9; p < 0.0001), ARF-stroke (RERI 32.3; p < 0.0001), AKI-MI (RERI 24.5; p = 0.0013), and ARF-sepsis (RERI 19.2; p < 0.0001). Two combinations demonstrated negative interaction: ARF-CA (RERI -65.1; p = 0.0017) and CA-transfusion (RERI -52.0, p < 0.0001).

CONCLUSIONS

Interaction effects exist between certain complications to increase the risk of short-term mortality. ARF, AKI, sepsis, and stroke were most likely to be involved in positive interactions. Further research into the mechanisms for these effects will be necessary to develop strategies to minimize the compounding effects of multiple complications in the perioperative period.

Troponin elevations after non-cardiac, non-vascular surgery are predictive of major adverse cardiac events and mortality: a systematic review and meta-analysis

BACKGROUND

Patients undergoing non-cardiac, non-vascular surgery are at risk of major cardiovascular complications. In non-cardiac surgery, troponin elevation has previously been shown to be an independent predictor of major adverse cardiac events and postoperative mortality; however, a majority of studies have focused on vascular surgery patients. The aim of this meta-analysis was to determine whether troponin elevation is a predictor of major adverse cardiac events and mortality within 30 days and 1 yr after non-cardiac, non-vascular surgery.

METHODS

A systematic review and meta-analysis was conducted in January 2016 according to the Meta-analysis Of Observational Studies in Epidemiology guidelines. Both interventional and observational studies measuring troponin within the first 4 days after surgery were eligible. A systematic search was performed in PubMed, EMBASE, Scopus, and the Cochrane Central Register of Controlled Trials.

RESULTS

Eleven eligible clinical studies (n=2193) were identified. A postoperative troponin elevation was a predictor of 30 day mortality, odds ratio (OR) 3.52 [95% confidence interval (CI) 2.21-5.62; I²=0%], and an independent predictor of 1 yr mortality, adjusted OR 2.53 (95% CI 1.20-5.36; I²=26%). A postoperative troponin elevation was associated with major adverse cardiac events at 30 days, OR 5.92 (95% CI 1.67-20.96; I²=86%), and 1 yr after surgery, adjusted OR 3.00 (95% CI 1.43-6.29; I²=21%).

CONCLUSIONS

Postoperative myocardial injury is an independent predictor of major adverse cardiac events and mortality within 30 days and 1 yr after non-cardiac, non-vascular surgery. The meta-analysis provides evidence that supports troponin monitoring as a cardiovascular risk stratification tool.

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.

Increased risk of acute arterial events in young patients and severely active IBD: a nationwide French cohort study

OBJECTIVE

Magnitude and independent drivers of the risk of acute arterial events in IBD are still unclear. We addressed this question in patients with IBD compared with the general population at a nationwide level.

DESIGN

Using the French National Hospital Discharge Database from 2008 to 2013, all patients aged 15 years or older and diagnosed with IBD were identified and followed up until 31 December 2013. The rates of incident acute arterial events were calculated and the impact of time with active disease (period around hospitalisation for IBD flare or IBD-related surgery) on the risk was assessed by Cox regression adjusted for traditional cardiovascular risk factors.

RESULTS

Among 210 162 individuals with IBD (Crohn's disease (CD), n=97 708; UC, n=112 454), 5554 incident acute arterial events were identified. Both patients with CD and UC had a statistically significant overall increased risk of acute arterial events (standardised incidence ratio (SIR) 1.35; 95% CI 1.30 to 1.41 and SIR 1.10; 95 CI 1.06 to 1.13, respectively). The highest risk was observed in patients under the age of 55 years, both in CD and UC. The 3-month periods before and after IBD-related hospitalisation were associated with an increased risk of acute arterial events in both CD and UC (HR 1.74; 95 CI 1.44 to 2.09 and 1.87; 95% CI 1.58 to 2.22, respectively).

CONCLUSION

Patients with IBD are at increased risk of acute arterial events, with the highest risk in young patients. Disease activity may also have an independent impact on the risk.

Revised cardiac risk index poorly predicts cardiovascular complications after adhesiolysis for small bowel obstruction

BACKGROUND

The number of patients undergoing preoperative risk stratification in the United States is expected to increase as the population ages. A large percentage of patients undergo some form of preoperative testing, and society guidelines suggest that up to 50% of the testing in lower risk surgical subgroups is unnecessary. The Revised Cardiac Risk Index and the risk calculator of the American College of Surgeons National Surgical Quality Improvement Program are widely used tools as the first step of preoperative cardiac evaluation. The Revised Cardiac Risk Index was developed to fill a need for objective perioperative cardiac risk evaluation. Despite the ease of use of Revised Cardiac Risk Index, it is uncertain if the stratification is accurate for surgical patients because its accuracy in large surgical samples has not been tested. With the National Surgical Quality Improvement Program risk calculator having excellent accuracy in estimating cardiac complications (area under the receiver operating characteristic 0.895), a unique opportunity to test the predictive accuracy of postsurgical cardiac events became available. The purpose of this study is to determine the accuracy of the Revised Cardiac Risk Index for predicting cardiovascular complications after adhesiolysis for small bowel obstruction.

METHODS

From 2005 to 2015, 34,032 cases of open or laparoscopic adhesiolysis (Current Procedural Terminology codes 44005 and 44180) for small bowel obstruction (International Classification of Diseases, 10th edition [ICD-10]) were analyzed using the National Surgical Quality Improvement Program dataset. Revised Cardiac Risk Index estimates were calculated for each case and compared to reported cardiovascular complications (myocardial infarction or cardiac arrest) using univariable logistic regression. Overall predictive accuracy was assessed by measuring model discrimination (area under the receiver operating characteristic) and model calibration (Hosmer-Lemeshow chi-squared statistics).

RESULTS

Although the Revised Cardiac Risk Index predicted cardiovascular complications with an odds ratio of 2.3 and a 95% confidence interval of 1.9 to 2.8 (P < .001) and the Hosmer-Lemeshow chi-square was significant (0.22, P = 0.64), the area under the receiver operating characteristic was poor (0.63, 95% confidence interval 0.59-0.67).

CONCLUSION

Despite its relative simplicity, the Revised Cardiac Risk Index performed poorly as a predictor of cardiovascular complications after adhesiolysis for small bowel obstruction. These findings question the utility of the Revised Cardiac Risk Index in this patient population. Future studies should aim to develop models that are computationally simple while retaining predictive accuracy.

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.

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

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

Cardiovascular dysfunction and liver transplantation

Cardiovascular complications have emerged as the leading cause of death after liver transplantation, particularly among those with advanced liver cirrhosis. Therefore, a thorough and accurate cardiovascular evaluation with clear comprehension of cirrhotic cardiomyopathy is recommended for optimal anesthetic management. However, cirrhotic patients manifest cardiac dysfunction concomitant with pronounced systemic hemodynamic changes, characterized by hyperdynamic circulation such as increased cardiac output, high heart rate, and decreased systemic vascular resistance. These unique features mask significant manifestations of cardiac dysfunction at rest, which makes it difficult to accurately evaluate cardiovascular status. In this review, we have summarized the current knowledge of heart and liver interactions, focusing on the usefulness and limitations of cardiac evaluation tools for identifying high-risk patients.

Myocardial injury after non-cardiac surgery: a perioperative affair?

Myocardial injury after non-cardiac surgery (MINS) is a rather new nosological entity and an unfortunately common perioperative complication. The diagnostic criteria for MINS, also indicated as isolated myocardial injury (IMI), are an elevated postoperative high sensitivity troponin T (hsTnT level ranging between 20 and 65 ng/L with an absolute change of at least 5 ng/L or hsTnT level >65 ng/L), in absence of symptoms and/or EKG findings suggestive of ischemia and without a non-ischemic etiology causing troponin elevation. MINS does not fulfill the universal definition of myocardial infarction even if it is related to ischemic causes and it is independently associated with 30-day postoperative mortality and complications. Nevertheless, mortality at 30 days in MINS patients has been calculated up to 10% and it increases exponentially as a function of peak postoperative troponin concentration. Physician and researchers should discriminate MINS from perioperative myocardial infarction and from not ischemic troponin increases. In the postoperative period, the possibility of missing the diagnosis of an acute coronary syndrome for the paucity of clinical symptoms or because physician failed to evaluate a postoperative EKG recording should always be considered. Physiopathology of MINS is not yet well defined: current hypotheses are surrogated from perioperative myocardial infarction studies. Up to now there are not specific treatments for MINS, even if antithrombotic therapy is under evaluation. Treatment decisions should be tailored to the individual case; potential benefits of troponin screening include a cardiology consultation and consequently, improved patients' information to promote lifestyle changes and enhanced therapy.

Increased neutrophil to lymphocyte ratio predicts myocardial injury in patients undergoing non-cardiac surgery

BACKGROUND

The neutrophil to lymphocyte ratio (NLR), has been proposed as potential indicator of cardiovascular events. Our aim was to determine the relationship between NLR and development of myocardial injury after non-cardiac surgery (MINS).

METHODS

This observational cohort study included 255 consecutive noncardiac surgery patients aged ≥45 years. Electrocardiography recordings and high sensitivity cardiac troponin T (hscTnT) levels of the patients were obtained for a period of 3 days postoperatively.

RESULTS

MINS was detected in 30 (11.8%) patients using the cut-off level of ≥14 ng/L for hscTnT. In the MINS group NLR (3.79 ± 0.7 vs. 2.69 ± 0.6, p < 0.000) values were higher than non-NLR group. The NLR to be independently associated with the development of MINS (OR: 11.690; CI: 4.619-29.585, p < 0.000).

CONCLUSIONS

NLR seems to be a simple, easy and cheap tool to predict the development of MINS in patient undergoing non-cardiac surgery.

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.

Spinal versus general anesthesia for lumbar spine surgery in high risk patients: Perioperative hemodynamic stability, complications and costs

OBJECTIVE

More stable perioperative hemodynamic conditions, lower costs and a lower perioperative complication rate were reported in young healthy patients undergoing lumbar spine surgery in spinal anesthesia (SA) compared to general anesthesia (GA). However, the benefits of SA in high risk patients (ASA≥II suffering from cardiovascular and/or pulmonary pathologies) undergoing this surgery are unclear. Our objective was to analyze whether SA leads to an improved perioperative hemodynamic stability and to a more cost-effective management compared to GA in high risk patients undergoing this surgery.

METHODS

In a retrospective analysis 146 ASA II-III patients who underwent lumbar spine surgery in SA were compared with 292 ASA I-III patients who were operated in GA between 2000 and 2014. Hemodynamic effects, hospitalization times, complications, and costs according to the Swiss billing system were assessed. The data extraction was conducted according to Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) initiative for cohort studies.

RESULTS

The patients in the SA group were older (75years (±9.6) vs 69 (±11.5), p<0.001), had a lower BMI (25.8kg/m2 (±4.8) vs 27.2 (±4.7), p=0.003) and showed a higher ASA score (3 vs 2, p<0.001). However, SA was associated with significantly better perioperative hemodynamic stability with less need for intraoperative vasopressors (15% vs 57%, p<0.001), volume supplementation (1113ml ±458 vs 1589±644, p<0.001) and transfusions (0% vs 4%, p<0.001). Additionally, the number of hypotension episodes was lower in the SA group (15% vs 47%, p<0.001). Furthermore, the SA group showed a significantly shorter duration of surgery (70min (±1.2) vs 91 (±41), p<0.001), lower postoperative nausea and vomiting (PONV) (4% vs 28%, p<0.001) and pain in the post anesthesia care unit (PACU) (visual analogue scale (VAS) 2.3 (±1.1) vs 0.8 (±0.8), p<0.001), whereas pain after 24h did not differ (VAS 0.9 (±1) vs 0.8 (±1.1), p=ns). The postoperative complication (7% vs 5%, p=0.286) and revision rates (4% vs 5%, p=0.626) were similar in both groups. Total costs (United States Dollars (USD) 6377 (±2332) vs 7018 (±4056), p=0.003) and PACU time were significantly lower in the SA group (35min (±12) vs 109 (±173), p<0.001).

CONCLUSIONS

Lumbar spine surgery in cardiovascular high risk patients with SA is safe, allows good perioperative hemodynamic stability and might lead to lower health care costs. Further prospective studies are needed to confirm these findings.