Cardiac complications after elective major vascular surgery

Value of Routine Troponin Measurement in Open Abdominal Aortic Aneurysm Repair

BACKGROUND

Cardiovascular complications are a major cause of morbidity and mortality in the postoperative period after major vascular surgery. Depending on the study population, up to 25% of patients have troponin elevation after noncardiac surgery, yet many do not meet the diagnosis of myocardial infarction (MI). Although outcomes of routine troponin elevation in patients undergoing mixed major vascular surgery have been evaluated, this has not been studied exclusively in elective, open abdominal aortic aneurysm repair (oAAA), especially regarding perioperative and overall mortality.

METHODS

We conducted a single-center, retrospective review of routine troponin surveillance for consecutive, oAAA from 2014 to 2019. A total of 319 patients were identified and analyzed for management patterns and interventions. The cohort was stratified into groups for comparison based on those in whom troponin was routinely checked (RC) as part of a care strategy during the study period, not routinely checked (NRC), elevated troponin (ET) >0.001 ng/mL, and not elevated. The median follow-up was 21.5 ± 23.8 months. Groups were compared on demographic data, cardiac comorbidities, 30-day and 3-year outcomes for MI and death using two-sample t-tests, Wilcoxon rank sum tests, Pearson chi-square tests, and Fisher exact tests when appropriate.

RESULTS

Troponin was measured in 83.7% (267/319) of patients who underwent elective oAAA repair. Routine troponin checks were obtained in 79.9% (255/319) of patients. ET was identified in 16.5% of those with RC (42/255) and 4.7% of those with NRC (3/64). Of patients with ET, 37.8% (17/45) had a cardiology consultation, 4.4% (2/45) had a percutaneous coronary intervention (PCI), and 4.4% (2/45) had another cardiac intervention. All 4 patients undergoing PCI or other cardiac intervention had received routine troponin checks. Patients with ET were older (71.2 vs. 68.6; P = 0.04), more likely to receive intraoperative blood products (P = 0.003), had longer operative times (P = 0.011), higher length of stay (9 vs. 7 days; P < 0.01), and higher 30-day MI rate (3 vs. 0; P = 0.04). They had neither longer aortic clamp times nor worse preoperative cardiac function, and the proximal clamp position during oAAA repair did not impact troponin detection. Additionally, 3-year overall mortality was increased in patients who had ET but there was not a significant difference in 3-year mortality between groups receiving routine troponin checks versus not.

CONCLUSIONS

ET, identified after elective oAAA repair, was associated with a higher risk of 30-day MI and lower overall survival. However, it was not demonstrated that routine assessment of troponin levels postoperatively leads to decreased 3-year mortality in this setting.

Critical Care of the Vascular Surgery Patient

Patients that require major vascular surgery suffer from widespread atherosclerosis and have multiple comorbidities that place them at increased risk for postoperative complications and require admission to the intensive care unit (ICU). Postoperative critical care of these patients is focused on hemodynamic optimization, and early identification and management of complications to improve outcomes.

Preexisting Right Ventricular Dysfunction Is Associated With Higher Postoperative Cardiac Complications and Longer Hospital Stay in High-Risk Patients Undergoing Nonemergent Major Vascular Surgery

OBJECTIVES

To evaluate whether the presence of preexisting right ventricular (RV) dysfunction in high-risk patients undergoing nonemergent major vascular surgery is associated independently with higher incidents of postoperative cardiac complications and a longer length of hospital stay.

DESIGN

Retrospective chart review.

SETTING

Single-center university hospital setting.

PARTICIPANTS

The patient population consisted of those identified as American Society of Anesthesiologists classification III and above who had a preoperative echocardiogram within 1 year of undergoing nonemergent major vascular surgery between January 2010 and May 2017.

MEASUREMENTS AND MAIN RESULTS

After multivariate analyses, RV dysfunction (RVD) is associated independently with a higher incidence of postoperative major cardiac complications with an odds ratio = 6.3 (95% confidence interval [CI], 1.0-38.5; p = 0.046). In addition, patients with RVD had a 50% longer length of stay than those without RVD (incident rate ratio [95% CI], 1.5 [1.2-1.8]; p < 0.001).

CONCLUSION

In this retrospective study of high-risk patients undergoing major vascular surgery, RV dysfunction was associated independently with a higher incidence of postoperative major cardiovascular events and longer length of hospital stays. Based on current findings, the prognostic value of RVD extends beyond the cardiac surgical cohort. Knowledge in management of patients with RVD in the perioperative setting should be understood by all anesthesiologists. Of note, a future study with a larger sample size is needed to validate the current findings given the small sample size of this study.

Acute perioperative-stress-induced increase of atherosclerotic plaque volume and vulnerability to rupture in apolipoprotein-E-deficient mice is amenable to statin treatment and IL-6 inhibition

Myocardial infarction and stroke are frequent after surgical procedures and consume a considerable amount of benefit of surgical therapy. Perioperative stress, induced by surgery, is composed of hemodynamic and inflammatory reactions. The effects of perioperative stress on atherosclerotic plaques are ill-defined. Murine models to investigate the influence of perioperative stress on plaque stability and rupture are not available. We developed a model to investigate the influence of perioperative stress on plaque growth and stability by exposing apolipoprotein-E-deficient mice, fed a high cholesterol diet for 7 weeks, to a double hit consisting of 30 min of laparotomy combined with a substantial blood loss (approximately 20% of total blood volume; 400 µl). The innominate artery was harvested 72 h after the intervention. Control groups were sham and baseline controls. Interleukin-6 (IL-6) and serum amyloid A (SAA) plasma levels were determined. Plaque load, vascular smooth muscle cell (VSMC) and macrophage content were quantified. Plaque stability was assessed using the Stary score and frequency of signs of plaque rupture were assessed. High-dose atorvastatin (80 mg/kg body weight/day) was administered for 6 days starting 3 days prior to the double hit. A single dose of an IL-6-neutralizing antibody or the fusion protein gp130-Fc selectively targeting IL-6 trans-signaling was subcutaneously injected. IL-6 plasma levels increased, peaking at 6 h after the intervention. SAA levels peaked at 24 h (n=4, P<0.01). Plaque volume increased significantly with the double hit compared to sham (n=8, P<0.01). More plaques were scored as complex or bearing signs of rupture after the double hit compared to sham (n=5-8, P<0.05). Relative VSMC and macrophage content remained unchanged. IL-6-inhibition or atorvastatin, but not blocking of IL-6 trans-signaling, significantly decreased plaque volume and complexity (n=8, P<0.01). Using this model, researchers will be able to further investigate the pathophysiology of perioperative plaque stability, which can result in myocardial infarction, and, additionally, to test potential protective strategies.

Summary: We developed a model to study the dynamics of atherosclerotic plaque growth and stability following surgery, and show that IL-6 inhibition and statins beneficially affect plaque volume and complexity.

Haemodynamic optimisation in lower limb arterial surgery: room for improvement?

BACKGROUND

Goal-directed therapy has been proposed to improve outcome in high-risk surgery patients. The aim of this study was to investigate whether individualised goal-directed therapy targeting stroke volume and oxygen delivery could reduce the number of patients with post-operative complications and shorten hospital length of stay after open elective lower limb arterial surgery.

METHODS

Forty patients scheduled for open elective lower limb arterial surgery were prospectively randomised. The LiDCO™plus system was used for haemodynamic monitoring. In the intervention group, stroke volume index was optimised by administering 250 ml aliquots of colloid intraoperatively and during the first 6 h post-operatively. Following surgery, fluid optimisation was supplemented with dobutamine, if necessary, targeting an oxygen delivery index level ≥ 600 ml/min(/) m(2) in the intervention group. Central haemodynamic data were blinded in control patients. Patients were followed up after 30 days.

RESULTS

In the intervention group, stroke volume index, and cardiac index were higher throughout the treatment period (45 ± 10 vs. 41 ± 10 ml/m(2), P < 0.001, and 3.19 ± 0.73 vs. 2.77 ± 0.76 l/min(/) m(2), P < 0.001, respectively) as well as post-operative oxygen delivery index (527 ± 120 vs. 431 ± 130 ml/min(/) m(2), P < 0.001). In the same group, 5/20 patients had one or more complications vs. 11/20 in the control group (P = 0.05). After adjusting for pre-operative and intraoperative differences, the odds ratio for ≥ 1 complications was 0.18 (0.04-0.85) in the intervention group (P = 0.03). The median length of hospital stay did not differ between groups.

CONCLUSION

Perioperative individualised goal-directed therapy may reduce post-operative complications in open elective lower limb arterial surgery.

[Perioperative myocardial damage in non-cardiac surgery patients]

Perioperative myocardial damage occurs with a high incidence depending on the operative procedure and the patients examined and is considered to be among the most relevant risk factors for increased perioperative morbidity and mortality in patients undergoing non-cardiac surgery. The pathophysiology of myocardial damage in the perioperative period is still not well understood. Both ischemia with and without acute coronary occlusion and non-ischemic stimuli can put a substantial strain on the heart in the perioperative period. However, in many cases the clinical presentation does not allow a clear differentiation between ischemic and non-ischemic myocardial damage. In the majority of cases perioperative myocardial infarctions occur with only mild or even without any clinical symptoms. This is probably due to a considerable difference in phenotype and pathophysiology between perioperative and non-perioperative myocardial infarctions. As a result of this unexplained etiology of perioperative myocardial infarction it remains an open question whether the contemporary diagnostic and therapeutic recommendations for the acute coronary syndrome can be extrapolated to the perioperative situation. The present review reflects the current state of knowledge and presents an optional approach to the diagnosis and therapy of perioperative myocardial injury.

Review article: The role of statins in reducing perioperative cardiac risk: physiologic and clinical perspectives

PURPOSE

To review the pathobiology and clinical implications of coronary vulnerable atherosclerotic plaques (VAPs), to discuss the role of statin therapy in VAP stabilization, and the potential benefits of perioperative statin therapy (PST) in reducing perioperative risk of acute coronary syndromes (ACSs).

SOURCE

MEDLINE search using "perioperative", "cardiac morbidity", "atherosclerosis", "vulnerable plaque", "statins" and combinations of these terms as keywords. The reference lists of relevant articles were further reviewed to identify additional citations.

PRINCIPAL FINDINGS

The nonstenotic, yet rupture-prone VAP causes most myocardial infarctions (MIs) and other ACSs, both in the nonsurgical and surgical patients. Large clinical trials in both primary and secondary prevention and in patients with ACSs have demonstrated that statin therapy will reduce cardiovascular morbidity and mortality across a broad spectrum of patient subgroups. These trials also suggest, and laboratory investigations establish, that statins possess favourable vascular effects independent of cholesterol reduction. Statins appear to interfere specifically with the pathophysiologic mechanisms implicated in atherothrombotic disease. Statins reduce vascular inflammation, improve endothelial function, stabilize VAPs, and reduce platelet aggregability and thrombus formation. Recent studies have shown that PST is associated with a reduced incidence of perioperative and long-term cardiovascular complications in high-risk patients. Combined therapy with statins and ss-blockers is a conceptually valid strategy targeting critical steps in the pathogenesis of an ACS.

CONCLUSION

Emerging evidence for the efficacy and safety of PST is promising, especially when combined with ss-blocker therapy in patients at highest risk. Confirmation of this early evidence awaits the results of ongoing and future prospective randomized controlled trials.

Pre-operative coronary revascularization: an optimal therapy for high-risk vascular surgery patients?

Cardiac complications are the leading cause of peri-operative morbidity and mortality of patients undergoing vascular surgery. This high incidence of cardiac complications is related to the presence of underlying coronary artery disease. The optimal treatment strategy for these high-risk patients, including the use of pre-operative coronary revascularization for the purpose of improving peri-operative and long-term cardiac outcomes, has been controversial for several decades. Recently, the results of the Coronary Artery Revascularization Prophylaxis (CARP) trial showed that in the short term there is no reduction in the number of post-operative myocardial infarctions, deaths or length of stay in the hospital, or in long-term outcomes in patients who underwent pre-operative coronary revascularization compared with patients who received optimized medical therapy. In this review, we summarize the role of pre-operative revascularization before elective vascular surgery using current evidence from the CARP trial and of those from published studies.

Influence of cardiac risk factors and medication on length of hospitalization in patients undergoing major vascular surgery

Major vascular surgery is associated with a long in-hospital length of stay (LOS). Cardiac risk factors identify patients with an increased risk. Recent studies have associated statin, aspirin, and beta-blocker therapies with improved postoperative outcome. However, the effect of all these factors on LOS has not been defined. Our aims were to determine the effect of cardiac risk factors and (preventive) statin, aspirin, and beta-blocker therapy on LOS and to deduce from these factors a model that predicts LOS. In total, 2,374 patients from 1990 to 2004 were enrolled. Mean LOS was 18 +/- 9 days. Cardiac risk factors that were significantly associated with LOS in the multivariable analysis were age, previous heart failure, hypertension, diabetes mellitus, renal failure, and chronic obstructive pulmonary disease. Statin and aspirin use was associated with a shorter LOS. Beta blockers shortened LOS only in patients with underlying coronary artery disease. Together, these factors explained 14.1% of the variance in LOS. In conclusion, in-hospital LOS in patients who undergo major vascular surgery can be predicted more accurately by clinical cardiac risk factors. A significant decrease in in-hospital LOS was achieved with statin, aspirin, and beta-blocker therapies.

Defining the high-risk patient for carotid endarterectomy: An analysis of the prospective National Surgical Quality Improvement Program database

BACKGROUND

Carotid endarterectomy (CEA) is the gold standard for the treatment of carotid stenosis, but carotid angioplasty and stenting has been advocated in high-risk patients. The definition of such a population has been elusive, particularly because the data are largely retrospective. Our study examined results for CEA in the National Surgical Quality Improvement Program database (both Veterans Affairs and private sector).

METHODS

National Surgical Quality Improvement Program data were gathered prospectively for all patients undergoing primary isolated CEA during the interval 2000 to 2003 at 123 Veterans Affairs and 14 private sector academic medical centers. Study end points included the 30-day occurrence of any stroke, death, or cardiac event. A variety of clinical, demographic, and operative variables were assessed with multivariate models to identify risk factors associated with the composite (stroke, death, or cardiac event) end point. Adjudication of end points was by trained nurse reviewers (previously validated).

RESULTS

A total of 13,622 CEAs were performed during the study period; 95% were on male patients, and 91% of cases were conducted within the Veterans Affairs sector. The average age was 68.6 +/- 0.1 years, and 42.1% of the population had no prior neurologic event. The composite stroke, death, or cardiac event rate was 4.0%; the stroke/death rate was 3.4%. Multivariate correlates of the composite outcome were (odds ratio, P value) as follows: deciles of age (1.13, .018), insulin-requiring diabetes (1.73, <.001), oral agent-controlled diabetes (1.39, .003), decade of pack-years smoking (1.04, >.001), history of transient ischemic attack (1.41, >.001), history of stroke (1.51, >.001), creatinine >1.5 mg/dL (1.48, >.001), hypoalbuminemia (1.49, >.001), and fourth quartile of operative time (1.44, >.001). Cardiopulmonary comorbid features did not affect the composite outcome in this model. Regional anesthesia was used in 2437 (18%) cases, with a resultant relative risk reduction for stroke (17%), death (24%), cardiac event (33%), and the composite outcome (31%; odds ratio, 0.69; P = .008).

CONCLUSIONS

Carotid endarterectomy results across a spectrum of Veterans Affairs and private sector hospitals compare favorably to contemporary studies. These data will assist in selecting patients who are at an increased risk for adverse outcomes. Use of regional anesthetic significantly reduced perioperative complications in a risk-adjusted model, thus suggesting that it is the anesthetic of choice when CEA is performed in high-risk patients.

Complications of major aortic and lower extremity vascular surgery

Atheromatous disease and invasive intervention of the aortoiliac and distal arteries are common. Morbidity and mortality have been reduced through understanding and management of patient risk factors. Complications of this form of treatment affect all organ systems; mortality is most frequently caused by a cardiovascular complication (eg, myocardial infarction). Infection, leading to aortoenteric fistula is a dreaded complication, and paraplegia, though rare, is a devastating outcome. Multiorgan failure and death may result from a systemic inflammatory response syndrome. Vascular surgery for infrainguinal disease also has a significant cardiovascular complication rate. Resulting complications may affect all organs; loss of an extremity may occur. The first part of this article reviews perioperative and postoperative complications of open aortic repair and lower-extremity revascularization and addresses the issue of regional anesthesia for major vascular surgery. The second part reviews endovascular aortic repair (EVAR). EVAR is a new intervention that combines surgery and radiology. Complications of EVAR are similar to open repair, but early results suggest they may be less frequent. New technology leads to new complications; endoleaks, migration of the endoprosthesis, and surgical conversion are unique to EVAR. The benefits of EVAR may be less blood loss, shorter hospitalization, and less cardiovascular stress; the risks may be aneurysm recurrence, prolonged surveillance and repeated secondary procedures. The development of EVAR, the complications, and the anesthesia-related concerns of EVAR, including its use in management of acute abdominal aortic aneurysm are reviewed.

Assessment and management of patients with ischemic heart disease

OBJECTIVE

Review the perioperative management of patients who are scheduled for noncardiac surgery.

DATA SOURCE

Review of literature (PubMed, MEDLINE).

CONCLUSIONS

Patients with ischemic heart disease who undergo noncardiac surgery are at significant risk of perioperative cardiac morbidity and mortality. Recent joint guidelines from the American College of Cardiology and American Heart Association have significantly streamlined the preoperative evaluation processes. Augmented hemodynamic control with intensive perioperative pharmacologic therapy with beta-blockers and possibly alpha-2 agonist has been shown to improve perioperative cardiovascular outcomes. However, translating this information to clinical practice continues to be a challenge and requires a multi- disciplinary approach. A particular intraoperative anesthetic technique is unlikely to influence perioperative cardiac morbidity and mortality. Postoperative management with goals of decreasing hemodynamic stress is important in patients with ischemic heart disease. Diagnosis and management of perioperative myocardial infarction continues to be a challenge. However, use of cardiac specific biomarkers should improve the diagnostic process.

Routine Measurement of Radioisotope Left Ventricular Ejection Fraction Prior to Vascular Surgery: Is it Worthwhile?

OBJECTIVE

To determine whether estimation of left ventricular (LV) ejection fraction (EF) by means of multiple gated acquisition (MUGA) scanning could reliably stratify cardiac risk prior to elective major vascular surgery.

METHODS

A review of the English-language literature.

RESULTS AND CONCLUSIONS

Twenty-two studies enrolling a total of 3096 patients were identified from 1984 to date. Selection bias, blinding of the results, different cut-off limits, and several retrospective studies were some of the problems preventing a comprehensive analysis. The resting LVEF was not found to be a consistent predictor of perioperative ischaemic cardiac events. In the perioperative phase, poor LV function was, mainly, predictive of congestive heart failure, and, in the long-term, of cardiac outcome. The presence of myocardial wall motion abnormalities was also associated with both a higher chance of postoperative cardiac complications and a worse long-term cardiac outcome. Although measurements of LV function seem to play a key role in defining a patient's long-term prognosis, the value of routinely measuring LVEF preoperatively is limited and, therefore, MUGA scanning cannot be recommended as a general screening test. Despite this, it has been widely used for cardiac risk assessment in vascular surgery, and only recently its popularity has started declining. Other tests, such as stress-echocardiography and myocardial perfusion imaging, used selectively in moderate-risk patients can refine prediction of cardiac risk. In the future, gated stress myocardial perfusion scintigraphy, perhaps combined with ANP/BNP plasma level determination, may become a first choice test in preoperative cardiac risk assessment.