Infrarenal abdominal aortic aneurysm repair: detection and treatment of associated carotid and coronary lesions

Pre-operative stress testing in the evaluation of patients undergoing non-cardiac surgery: A systematic review and meta-analysis

Background

Pre-operative stress testing is widely used to evaluate patients for non-cardiac surgeries. However, its value in predicting peri-operative mortality is uncertain. The objective of this study is to assess the type and quality of available evidence in a comprehensive and statistically rigorous evaluation regarding the effectiveness of pre-operative stress testing in reducing 30-day post -operative mortality following non -cardiac surgery.

Methods

The databases of MEDLINE, EMBASE, and CENTRAL databases (from inception to January 27, 2016) were searched for all studies in English. We included studies with pre-operative stress testing prior to 10 different non-cardiac surgery among adults and excluded studies with sample size<15. The data on study characteristics, methodology and outcomes were extracted independently by two observers and checked by two other observers. The primary outcome was 30-day mortality. We performed random effects meta-analysis to estimate relative risk (RR) and 95% confidence intervals (95% CI) in two-group comparison and pooled the rates for stress test alone. Heterogeneity was assessed using I² and methodological quality of studies using Newcastle-Ottawa Quality Assessment Scale. The predefined protocol was registered in PROSPERO #CRD42016049212.

Results

From 1807 abstracts, 79 studies were eligible (297,534 patients): 40 had information on 30-day mortality, of which 6 studies compared stress test versus no stress test. The risk of 30-day mortality was not significant in the comparison of stress testing versus none (RR: 0.79, 95% CI = 0.35–1.80) along with weak evidence for heterogeneity. For the studies that evaluated stress testing without a comparison group, the pooled rates are 1.98% (95% CI = 1.25–2.85) with a high heterogeneity. There was evidence of potential publication bias and small study effects.

Conclusions

Despite substantial interest and research over the past 40 years to predict 30-day mortality risk among patients undergoing non-cardiac surgery, the current body of evidence is insufficient to derive a definitive conclusion as to whether stress testing leads to reduced peri-operative mortality.

Frequency of coronary artery disease in patients undergoing peripheral artery disease surgery

The prevalence of coronary artery disease (CAD) in patients with peripheral arterial disease (PAD) varies widely in published reports. This is likely due at least in part to significant differences in how PAD and CAD were both defined and diagnosed. In this report, the investigators describe 78 patients with PAD who underwent preoperative coronary angiography before elective peripheral revascularization and provide a review of published case series. Among the patients included, the number with concomitant CAD varied from 55% in those with lower-extremity stenoses to as high as 80% in those with carotid artery disease. The number of coronary arteries narrowed by ≥ 50% was 1 in 28%, 2 in 24%, and 3 in 19%; 28% did not have any angiographic evidence of CAD. The review of published research resulted in the identification of 19 case series in which a total of 3,969 patients underwent preoperative coronary angiography before elective PAD surgery; in the 2,687 who were described according to the location of the PAD, 55% had ≥ 1 epicardial coronary artery with ≥ 70% diameter narrowing. The highest prevalence of concomitant CAD was in patients with severe carotid artery disease (64%). In conclusion, despite sharing similar risk factors, the prevalence of obstructive CAD in patients with PAD ranges widely and appears to differ across PAD locations. Thus, the decision to perform coronary angiography should be based on indications independent of the planned PAD surgery.

Guidelines for Screening of Extracranial Carotid Artery Disease: A Statement for Healthcare Professionals from the Multidisciplinary Practice Guidelines Committee of the American Society of Neuroimaging; Cosponsored by the Society of Vascular and Interventional Neurology

The aim of this new statement is to provide comprehensive and timely evidence-based recommendations on the screening for asymptomatic carotid artery stenosis in the general population and selected subsets of patients. Recommendations are included for high-risk persons in the general population; patients undergoing open heart surgery including coronary artery bypass surgery; patients with peripheral vascular diseases, abdominal aortic aneurysms, and renal artery stenosis; patients after radiotherapy for head and neck malignancies; patients following carotid endarterectomy, or carotid artery stent placement; patients with retinal ischemic syndromes; patients with syncope, dizziness, vertigo or tinnitus; and patients with a family history of vascular diseases and hyperhomocysteinemia. The recommendations are based on prevalence of disease, anticipated benefit, and concurrent guidelines from other professional organizations in selected populations.

Estenose carotídea acima de 70% em pacientes no pré-operatório de cirurgia da aorta abdominal: freqüência e fatores de risco

OBJETIVO: Analisar a freqüência e os fatores de risco associados à estenose carotídea acima de 70% em pacientes que serão submetidos a cirurgias de aorta abdominal. MATERIAL E MÉTODO: Foram analisados 94 pacientes que realizaram ultra-som Doppler de carótidas no pré-operatório de cirurgias de aorta abdominal entre janeiro de 2000 e janeiro de 2003, pela disciplina de Cirurgia Vascular da Santa Casa de São Paulo. RESULTADOS: Sessenta e sete pacientes (71%) eram homens. Dentre os 94 pacientes, 42 (44,6%) tinham doença oclusiva aorto-ilíaca, e 52 (53,4%), aneurismas da aorta abdominal (AAA). A análise dos dados mostrou uma prevalência de estenose de carótidas acima de 70% em 8,33% dos pacientes com AAA e em 13,51% dos pacientes com doença oclusiva aorto-ilíaca, diferença esta sem significância estatística (P = 0,5). Nos pacientes que apresentavam antecedente de isquemia cerebral - acidente vascular cerebral (AVC) ou ataque isquêmico transitório (AIT) -, houve uma prevalência estatisticamente maior de estenose carotídea entre 70 e 99%. Outros fatores de risco para aterosclerose, como sexo masculino, diabetes, hipertensão arterial e tabagismo, não foram preditivos da presença de estenose carotídea acima de 70%. CONCLUSÃO: A freqüência de estenose da carótida acima de 70% em pacientes no pré-operatório de cirurgia de aorta foi de 9,57%, e a presença de antecedente de AVC ou AIT na história foi preditiva de estenose acima de 70% neste grupo de pacientes.

Risk for stroke after elective noncarotid vascular surgery

INTRODUCTION

Patients undergoing operations to treat peripheral vascular disease have systemic atherosclerosis and are at risk for stroke. However, the incidence and effect of cerebrovascular events on noncarotid vascular surgical outcomes are not well-defined.

METHODS

Patients undergoing common operations for vascular disease from 1997 to 2000 were examined with data from the Veterans Affairs (VA) National Surgery Quality Improvement Project and the VA patient treatment files. Operations studied included abdominal aortic aneurysmectomy (n = 2551), aortobifemoral bypass (n = 2616), lower extremity bypass (n = 6866), and major lower extremity amputation (n = 7442). The incidence of perioperative stroke was determined, and logistic regression analysis was used to identify independent risk factors for stroke. Logistic and linear regression analyses were used to quantify the effect of postoperative stroke on adjusted mortality and length of stay. Odds ratio (OR) and 95% confidence interval (CI) were defined. P <.05 was considered significant.

RESULTS

Stroke was uncommon after noncarotid vascular procedures, occurring in only 0.4% to 0.6% of patients. Independent risk factors for stroke include preoperative ventilation (OR, 11; 95% CI, 5.0-22.3; P <.001), previous stroke or transient ischemic attack (OR, 4.2; 95% CI, 2.7-6.4; P <.001), postoperative myocardial infarction (OR, 3.3; 95% CI, 1.3-8.7; P =.009), and need to return to the operating room (OR, 2.2; 95% CI, 1.4-3.5; P =.001). Factors that did not appear to be associated with stroke risk included procedure type, diabetes, renal failure, dialysis dependence, number of transfused units of blood, and hypertension. After controlling for other postoperative complications and comorbid conditions, postoperative stroke significantly increased the risk for perioperative mortality (OR, 6.3; 95% CI, 3.4-11.4; P <.001), with similar magnitude as postoperative myocardial infarction (OR, 6.3; 95% CI, 3.9-10.1; P <.001). Stroke was also associated with a 48% increase in overall length of stay.

CONCLUSIONS

Stroke after noncarotid peripheral vascular surgery is uncommon, but results in markedly increased mortality and length of stay. Stroke risk is most strongly associated with previous stroke history and greater degree of illness. Patients with these associated conditions deserve particular attention to assessing and medically managing modifiable risk factors.

Use of near-infrared spectroscopy to monitor regional cerebral oxygen saturation during infrarenal aortic crossclamping in piglets

PURPOSE

The hemodynamic changes induced by infrarenal aortic crossclamping have been well documented, but the effects of such crossclamping on cerebral perfusion are unknown. To investigate these effects, we used near-infrared spectroscopy (NIRS) to monitor regional cerebral oxygen saturation (rSO2) during infrarenal aortic crossclamping in a piglet model.

METHODS

The study involved 19 piglets, each weighing 7.8 +/- 1 kg. The NIRS sensor was placed on each animal's forehead. General anesthesia was induced, and the infrarenal abdominal aorta was mobilized through a laparotomy. After heparin (1 mg/kg) was administered, crossclamps were applied proximally and distally. A 2 mm segment was resected from the proximal aortic stump, and an aorto-aortic anastomosis was performed.

RESULTS

Crossclamping lasted for 30.6 +/- 6.7 min. Between the time of baseline measurement and clamp application, the rSO2 did not decrease significantly (65.4%+/- 8.9% vs. 62.4%+/- 7.8%). However, significant decreases in the rSO2 occurred between baseline measurement and clamp removal (65.4%+/- 8.9% vs. 55.7%+/- 8.9%; P<0.01), between baseline measurement and the end of surgery (65.4%+/- 8.9% vs. 57.7%+/- 7.5%; P<0.01), and between clamp application and removal (62.4%+/- 7.8% vs. 55.7%+/- 8.9%; P<0.01). At these same intervals, no intergroup differences occurred in the temperature, heart rate, or mean arterial pressure.

CONCLUSION

Infrarenal aortic crossclamping significantly decreases the rSO2. NIRS, which has the advantages of being non-invasive and continuous, may be useful for monitoring this variable intraoperatively.

Cost of routine screening for carotid and lower extremity occlusive disease in patients with abdominal aortic aneurysms

OBJECTIVE

The burden of clinically relevant noncoronary atherosclerotic occlusive disease in patients with abdominal aortic aneurysms (AAAs) is poorly defined. Furthermore, the cost-effectiveness of routine versus selective preoperative noninvasive examination of the carotid and lower extremity arterial beds has not been established in patients who undergo elective AAA repair.

METHODS

Diagnostic vascular laboratory study results were reviewed in 206 patients who underwent evaluation before AAA repair from 1994 to 1998. The patients underwent routine preoperative carotid duplex scan examinations and lower extremity Doppler scan arterial studies with ankle-brachial index (ABI) determinations. The medical records were reviewed for the identification of clinical evidence consistent with cerebrovascular or lower extremity arterial occlusive disease. The costs of routine screening and selective screening were determined with Medicare reimbursement schedules.

RESULTS

The prevalence rate of advanced (80% to 100%) carotid artery stenosis (CAS) was 3.4%, and 18% of the patients had CAS between 60% and 100%. Advanced peripheral vascular occlusive disease (PVOD; ABI, <0.3) was found in 3% of the patients, and 12% of the patients had an ABI of less than 0.6. Most patients with advanced CAS (71%) or advanced PVOD (83%) had clinical indications of their disease. The absence of clinical evidence of disease had a negative predictive value of 99% for both advanced CAS and PVOD. The cost of routine screening for all patients for advanced CAS was $5445 per case. Routine screening for severe PVOD costs were $3732 per case discovered. In contrast, the costs for selective screening for advanced CAS or PVOD in patients with appropriate history or symptoms were $1258 and $785 per case found, respectively.

CONCLUSION

Routine noninvasive diagnostic testing for the identification of asymptomatic CAS and PVOD in patients with AAA may not be justified. Preoperative screening is more clearly indicated for patients with AAAs who have clinical evidence suggestive of CAS or PVOD.

The prevalence of carotid artery stenosis in patients undergoing aortic reconstruction

BACKGROUND

Coronary artery disease occurs frequently in patients undergoing aortic reconstruction, and it has been presumed that internal carotid artery occlusive disease is also common. This has led to the practice of screening for and repairing significant carotid lesions in asymptomatic patients prior to aortic reconstruction. The purpose of this study was to determine the true prevalence of internal carotid artery disease in these patients.

METHODS

The records of 240 patients who underwent duplex ultrasound screening for carotid artery disease prior to aortic reconstruction were reviewed. Surgery was performed for aortic aneurysm (AA) or aorto-iliac occlusive disease (AO). The prevalence of hyperlipidemia and coronary artery disease was similar between the two groups, but tobacco use, hypertension, and diabetes mellitus differed.

RESULTS

Internal carotid artery stenosis > or = 50% occurred in 26.7% of the total group (64 of 240 cases). Stenosis > or = 50% was more common in the AO group (40 of 101 cases, 39.6%) than the AA group (24 of 139 cases, 17.3%, P = 0.0001). Severe disease (70% to 99%) was also more common in the AO group than the AA group (9.9% versus 3.6%, P = 0.0464).

CONCLUSION

Internal carotid artery disease occurs commonly in patients undergoing aortic reconstruction, and screening is worthwhile. Significant disease is more common in patients with aorto-iliac occlusive disease than in those with aortic aneurysm, although atherosclerotic risk factors occur with varying frequency in the two groups. These findings suggest that additional factors may contribute to the higher prevalence of internal carotid artery stenosis in aorto-iliac occlusive disease.