Use of intraoperative epiaortic ultrasonography to delineate aortic atheroma

2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization: A Report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines

AIM

The guideline for coronary artery revascularization replaces the 2011 coronary artery bypass graft surgery and the 2011 and 2015 percutaneous coronary intervention guidelines, providing a patient-centric approach to guide clinicians in the treatment of patients with significant coronary artery disease undergoing coronary revascularization as well as the supporting documentation to encourage their use.

METHODS

A comprehensive literature search was conducted from May 2019 to September 2019, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Collaboration, CINHL Complete, and other relevant databases. Additional relevant studies, published through May 2021, were also considered.

STRUCTURE

Coronary artery disease remains a leading cause of morbidity and mortality globally. Coronary revascularization is an important therapeutic option when managing patients with coronary artery disease. The 2021 coronary artery revascularization guideline provides recommendations based on contemporary evidence for the treatment of these patients. The recommendations present an evidence-based approach to managing patients with coronary artery disease who are being considered for coronary revascularization, with the intent to improve quality of care and align with patients' interests.

Surgical strategies for severely atherosclerotic (porcelain) aorta during coronary artery bypass grafting

Porcelain aorta (PA) is an asymptomatic atherosclerotic disease, characterized by circumferential calcification throughout the whole perimeter of the aorta. It is seen in 2% to 9.3% of patients undergoing elective coronary artery bypass grafting (CABG) and makes manipulation of the ascending aorta impossible. It has been clearly shown that most emboli seen and detected during the CABG procedure occur during aortic cross-clamping and aortic side-clamping. Manipulation of porcelain or a severely atherosclerotic aorta increases the risk of perioperative stroke. The incidence of stroke after CABG is between 0.48% and 2.9%, and the risk is correlated with the extent and severity of the atherosclerotic disease. A conventional CABG procedure involves successive steps that include cannulation of the ascending aorta, application of a cross-clamp to the aorta, and partial clamping of the aorta to create the proximal anastomosis. Therefore in procedures that involve cannulation, clamping, or proximal anastomosis, and where aortic manipulation is inevitable, preassessment of the atherosclerotic aortic plaques is crucial. Although many surgeons still rely on intraoperative manual aortic palpation, this approach has very low sensitivity and underestimates the severity of the atherosclerotic illness. Imaging methods including preoperative computed tomography or intraoperative epiaortic ultrasonography enable modification of the surgical technique according to the severity of atherosclerosis. Various surgical techniques have been described to reduce the risk of atheroembolism that may lead to cerebrovascular events in patients with severely atherosclerotic ascending aorta. Anaortic or "no-touch" techniques that do not utilize aortic manipulation may significantly decrease the development of neurological complications by avoiding aortic maneuvers known to cause emboli. In cases where severe atherosclerotic disease or other factors preclude safe use of the ascending aorta, modifications in the surgical techniques, such as switching to different cannulation sites including the axillary/subclavian, femoral and innominate arteries, or using hypothermic ventricular fibrillation and in-situ pedicled arterial grafts, or performing proximal anastomoses at alternative anatomical locations will enable CABG operations to be performed safely with low morbidity and mortality rates in patients with porcelain aortas.

Animal Study of a Novel Device for Clamp-less Proximal Anastomosis in Coronary Bypass Surgery

PURPOSE

Limitations of existing techniques for clampless proximal anastomosis (CPA) in CABG include air emboli and excessive bleeding. This study evaluated the safety and performance of a new device for performing CPA.

DESCRIPTION

The device includes a temporary adjustable sealing element which is connected via a catheter to a handle that controls its opening and closure. An aortic punch is mounted on the catheter and activated by a detachable handle.

EVALUATION

Six adult female swine underwent partial CABG which included construction of CPA using autologous arterial or venous conduits. During anastomosis construction, good sealing was achieved in all cases and in 4/6 animals there was no need for use of a blower. In the first two cases, blower was intermittently used in 14% of the entire anastomosis construction time. Mean flow rate of 140.0±52.9 ml/min was measured for the arterial grafts and 666.7±230.9 ml/min for the venous grafts.

CONCLUSIONS

The VIOLA device is safe and associated with good hemostasis and minimal use of a blower during CPA construction in swine model.

Ultrasound Methods in the Evaluation of Atherosclerosis: From Pathophysiology to Clinic

Atherosclerosis is a key pathological process that causes a plethora of pathologies, including coronary artery disease, peripheral artery disease, and ischemic stroke. The silent progression of the atherosclerotic disease prompts for new surveillance tools that can visualize, characterize, and provide a risk evaluation of the atherosclerotic plaque. Conventional ultrasound methods-bright (B)-mode US plus Doppler mode-provide a rapid, cost-efficient way to visualize an established plaque and give a rapid risk stratification of the patient through the Gray-Weale standardization-echolucent plaques with ≥50% stenosis have a significantly greater risk of ipsilateral stroke. Although rather disputed, the measurement of carotid intima-media thickness (C-IMT) may prove useful in identifying subclinical atherosclerosis. In addition, contrast-enhanced ultrasonography (CEUS) allows for a better image resolution and the visualization and quantification of plaque neovascularization, which has been correlated with future cardiovascular events. Newly emerging elastography techniques such as strain elastography and shear-wave elastography add a new dimension to this evaluation-the biomechanics of the arterial wall, which is altered in atherosclerosis. The invasive counterpart, intravascular ultrasound (IVUS), enables an individualized assessment of the anti-atherosclerotic therapies, as well as a direct risk assessment of these lesions through virtual histology IVUS.

Does epiaortic ultrasound screening reduce perioperative stroke in patients undergoing coronary surgery? A topical review

Although the occurrence of stroke in patients undergoing coronary artery bypass grafting (CABG) is decreasing, it remains an important concern. Therefore, it is important to identify and adopt strategies that can decrease the incidence of stroke in these patients. One of the strategies that have demonstrated the potential to decrease the rate of post-CABG stroke is an assessment of aorta for atherosclerosis before surgery and changing the surgical plan accordingly to minimize the stroke risk. This assessment can be done through palpation of the aorta, transesophageal echocardiography (TEE), and epiaortic ultrasound scanning (EAS). EAS has shown superiority over both palpation and TEE for intraoperative evaluation of aorta. However, despite the evidence demonstrating reduced stroke rates with the EAS-guided approach, EAS is not yet the standard of care procedure in patients undergoing CABG. Therefore, we have reviewed the literature for evidence that supports the routine use of EAS in patients undergoing coronary surgery and have presented solutions to overcome the barriers to its routine use.

The use of intraoperative epiaortic ultrasonography in monitoring patients over 75 years old treated with aortic valve replacement

Introduction

Epiaortic ultrasound scanning (EAS) extended the use of ultrasound to the intraoperative diagnosis of aortic pathology. Surgical palpation of the ascending aorta underestimates the presence and severity of atherosclerotic plaques. Epiaortic ultrasound scanning has been used as an adjunct to transesophageal echocardiography (TEE) or as a primary direct diagnostic tool for imaging the ascending aorta as well as the aortic arch, which gained prominence as part of a multipronged intraoperative strategy to reduce atherosclerotic emboli.

Aim

To compare the epiaortic examination with transthoracic and transesophageal echo (transthoracic echocardiography (TTE) and TEE), X-ray, surgical intraoperative palpation, and postoperative neurological status.

Material and methods

The analyzed group consisted of 35 patients (mean age: 81.3 years) treated with aortic valve replacement (AVR), either alone (60%) or combined with coronary artery bypass grafting (CABG; 22.8%) or aortic aneurysm replacement (11.42%). In 2 patients, only CABG was performed because intraoperatively reevaluated strategy. Thierteen patients have got a history of diabetes, 10 chronic renal failure and 3 of cerebral stroke.

Results

In more than 80% of patients, positive EAS results had an influence on the choice of aortic clamping site and in 50% of patients on the site of cannulation. Female sex, peripheral vascular disease, history of previous stroke, and calcifications in the ascending aorta in TTE have significant predictive value for recognizing atherosclerotic changes in EAS and the risk of postoperative neurological complications in octogenarians treated with AVR.

Conclusions

Epiaortic ultrasound scanning imaging is superior to TTE and manual palpation in the detection and localization of ascending atherosclerosis. This technique should be introduced as a standard perioperative examination in older patients at risk of neurological complications.

Imaging Techniques for Diagnosis of Thoracic Aortic Atherosclerosis

The most severe complications after cardiac surgery are neurological complications including stroke which is often caused by emboli merging from atherosclerosis in the ascending aorta to the brain. Information about the thoracic aorta is crucial in reducing the embolization risk for both surgical open and closed chest procedures such as transaortic heart valve implantation. Several techniques are available to screen the ascending aorta, for example, transesophageal echocardiography (TEE), epiaortic ultrasound, TEE A-view method, manual palpation, computed tomography, and magnetic resonance imaging. This paper provides a description of the advantages and disadvantages of these imaging techniques.

Innovative approaches in the perioperative care of the cardiac surgical patient in the operating room and intensive care unit

Perioperative care for cardiac surgery is undergoing rapid evolution. Many of the changes involve the application of novel technologies to tackle common challenges in optimizing perioperative management. Herein, we illustrate recent advances in perioperative management by focusing on a number of novel components that we judge to be particularly important. These include: the introduction of brain and somatic oximetry; transesophageal echocardiographic hemodynamic monitoring and bedside focused ultrasound; ultrasound-guided vascular access; point-of-care coagulation surveillance; right ventricular pressure monitoring; novel inhaled treatment for right ventricular failure; new approaches for postoperative pain management; novel approaches in specialized care procedures to ensure quality control; and specific approaches to optimize the management for postoperative cardiac arrest. Herein, we discuss the reasons that each of these components are particularly important in improving perioperative care, describe how they can be addressed, and their impact in the care of patients who undergo cardiac surgery.

Avoiding aortic clamping during coronary artery bypass grafting reduces postoperative stroke

OBJECTIVE

The purpose of this study was to determine whether the incidence of postoperative stroke could be reduced by eliminating aortic clamping during coronary artery bypass grafting.

METHODS

From 2002 to 2013, 12,079 patients underwent primary, isolated coronary artery bypass grafting at a single US academic institution. Aortic manipulation was completely avoided by using in situ internal thoracic arteries for inflow in 1552 patients (12.9%) (no-touch), a clampless facilitating device for proximal anastomoses in 1548 patients (12.8%), and aortic clamping in 8979 patients (74.3%). These strategies were assessed in a logistic regression model controlling for relevant variables.

RESULTS

The overall incidence of postoperative stroke was 1.4% (n = 165), with an unadjusted incidence of 0.6% (n = 10) in the no-touch group, 1.2% (n = 18) in the clampless facilitating device group, and 1.5% (n = 137) in the clamp group (P < .01 for no-touch vs clamp). The ratio of observed to expected stroke rate increased as the degree of aortic manipulation increased, from 0.48 in the no-touch group, to 0.61 in the clampless facilitating device group, and to 0.95 in the clamp group. Aortic clamping was independently associated with an increase in postoperative stroke compared with a no-touch technique (adjusted odds ratio, 2.50; P < .01). When separated by cardiopulmonary bypass use, both the off-pump partial clamp and the on-pump crossclamp techniques increased the risk of postoperative stroke compared with no-touch (adjusted odds ratio, 2.52, P < .01; and adjusted odds ratio, 4.25, P < .001, respectively).

CONCLUSIONS

A no-aortic touch technique has the lowest risk for postoperative stroke for patients undergoing coronary artery bypass grafting. Clamping the aorta during coronary artery bypass grafting increases the risk of postoperative stroke, regardless of the severity of aortic disease.

Perioperative Echocardiography

Echocardiography has been utilized perioperatively since the 1970s and many studies have been conducted to prove its efficacy. Epicardiac echocardiography (EE) is the modality of choice when transesophageal echocardiography (TEE) is contraindicated or when aortic atherosclerosis is suspected. Perioperative TEE has shown to be an excellent tool in the operating room for assessment, diagnosis, surgical guidance, and outcome evaluation. Pediatric surgery has also shown better surgical outcomes for congenital disease states with the guidance of TEE. The cardiac Sonographer’s role in the operating room is a very important one because it involves operating the ultrasound machine and communicating image interpretations to surgeons in a timely and efficient manner. Cardiac Sonographers eager to progress in their careers can take advantage of this opportunity to enhance their clinical and educational qualifications. Technology is advancing quickly with the breakthrough of 3D and 4D TEE, where images are captured in real time, providing improved diagnoses and prognosis. This article discusses the evolution of echocardiography in the operating room and its future impact on perioperative evaluation, with attention paid to the role of cardiac Sonographers and the future clinical progression in their scope of practice.

Trends in aortic clamp use during coronary artery bypass surgery: effect of aortic clamping strategies on neurologic outcomes

OBJECTIVE

The purpose of the present study was to determine the effect of different clamping strategies during coronary artery bypass grafting on the incidence of postoperative stroke.

METHODS

In the present case-control study, all patients at Emory hospitals from 2002 to 2009 with postoperative stroke after isolated coronary artery bypass grafting (n = 141) were matched 1:4 to a contemporaneous cohort of patients without postoperative stroke (n = 565). The patients were matched according to the Society of Thoracic Surgeons' predicted risk of postoperative stroke score, which is based on 26 variables. The patients who received on-pump and off-pump coronary artery bypass grafting were matched separately. Multiple logistic regression analysis with adjusted odds ratios was performed to identify the operative variables associated with postoperative stroke.

RESULTS

Among the on-pump cohort, the single crossclamp technique was associated with a decreased risk of stroke compared with the double clamp (crossclamp plus partial clamp) technique (odds ratio, 0.385; P = .044). Within the on-pump cohort, no significant difference was seen in the incidence of stroke according to clamp use. Epiaortic ultrasound of the ascending aorta increased from 45.3% in 2002 to 89.4% in 2009. From 2002 to 2009, clamp use decreased from 97.7% of cases to 72.7%.

CONCLUSIONS

During on-pump coronary artery bypass grafting, the use of a single crossclamp compared with the double clamp technique decreased the risk of postoperative stroke. The use of any aortic clamp decreased and epiaortic ultrasound use increased from 2002 to 2009, indicating a change in the operative technique and surgeon awareness of the potential complications associated with manipulation of the aorta.

Risks of Stroke After Coronary Artery Bypass Graft - Recent Insights and Perspectives

Stroke is one of the most devastating complications after coronary artery bypass graft (CABG) surgery, entailing permanent disability, a 3-6 fold increased risk of mortality, an incremental hospital resource consumption and a longer length of hospital stay. Notwithstanding advances in surgical, anaesthetic and medical management across the last 10 years, the risk of stroke after CABG has not significantly declined, likely because an older and sicker population is now deemed suitable to undergo CABG. The pathogenesis of stroke is multifactorial, but two variables are believed to play a major role - cerebral embolisation of atheromatous debris arising from the ascending aorta during surgical manipulation and hypoperfusion during surgery. Identification of vulnerable patients at increased risk of stroke before CABG is of paramount importance for the surgical decision-making approach and informed consent. Several models including demographic, clinical and procedural variables have been developed to risk-stratify the hazard of stroke in patients undergoing CABG, but identification of severe atherosclerosis of the ascending aorta and pre-existing cerebrovascular disease are key determinants for appropriate risk stratification and decision-making. Atherosclerotic disease of the ascending aorta can be identified before surgery using transoesophageal echocardiography, computed tomography and magnetic resonance imaging. However, intra-operative ultrasound scanning of the ascending aorta is the diagnostic tool with the best sensitivity and specificity for the detection of atheromatous debris in the ascending aorta. Although many investigators have advocated the use of off-pump CABG to minimise the risk of peri-operative stroke, results from randomised trials and meta-analyses have been inconsistent. Anaortic approaches, including total arterial revascularisation with in situ grafting of both mammary arteries, or the use of the HEARTSTRING® seal device avoid any manipulation of the aorta, thus potentially minimising the risk of stroke in high-risk patients. Assessment and treatment of severe carotid artery disease, and aggressive and prompt treatment of post-operative atrial fibrillation are other important strategies that should be routinely implemented to reduce the risk of stroke in patients undergoing CABG.

Coronary-coronary bypass grafting to reduce the risk of aortic atheroembolism

Coronary-coronary bypass grafting refers to making anastomoses between two segments of the same coronary artery or between different coronary arteries, and provides less "touch" to the aorta, which is important for the patients with severely atherosclerotic ascending aorta. In this report we represent a case of a patient with extensive atherosclerotic aorta, in whom a saphenous vein graft was placed between the acute marginal and the posterior-descending branches of the right coronary artery during an off-pump coronary artery bypass grafting surgery.

A multimodal approach to the prevention of postoperative stroke in patients undergoing coronary artery bypass surgery

BACKGROUND

Stroke is known to be multifactorial in origin. This study was designed to assess the effectiveness of a multimodal approach to preventing this complication in patients undergoing coronary artery bypass.

METHODS

One thousand five hundred thirty consecutive coronary artery bypass patients operated on by a single surgeon from July 1994 to April 2008 were studied. Group 1 patients (n = 1,214) were operated on before 2004. Group 2 patients (n = 316) were operated on after 2004. In group 2 patients, epiaortic scanning, selective use of proximal anastomotic devices, and alternative cannulation were used. Off-pump coronary artery bypass (OPCAB) was used in 730 patients. On-pump coronary artery bypass (ONCAB) was used in 800 patients. Preoperative risk factors including age, cerebrovascular disease, peripheral vascular disease, hypertension, and diabetes were examined in all patients. The incidence of postoperative stroke was determined for group 1 and 2 patients and the individual cohorts of OPCAB and ONCAB patients.

RESULTS

The overall incidence of stroke was 1.6% (25/1,530). The postoperative incidence of stroke was 1.7% (21/1,214) in group 1 patients as compared with 1.3% (4/316) in group 2 patients. The incidence of postoperative stroke was 2.4% (19/800) in ONCAB patients as compared with 0.8% (6/730) in OPCAB patients (P < .05).

CONCLUSIONS

OPCAB is an important tool for the prevention of postoperative stroke. Adjunctive techniques for the prevention of emboli from the ascending aorta may also reduce the risk of stroke in OPCAB and ONCAB patients.

Intraoperative Epiaortic Ultrasound Scanning Guides Operative Strategies and Identifies Patients at High Risk during Coronary Artery Bypass Grafting

Objective

Epiaortic ultrasound (EU) reliably reveals ascending aortic atherosclerosis (AAA), allowing strategies to minimize the risk of embolization or plaque disruption during coronary artery bypass grafting. Our objective was to delineate if EU-guided intervention improved outcomes.

Methods

Patients undergoing coronary artery bypass grafting (2004–2007) were categorized by EU grade (grade 1–2 [mild] vs. 3–5 [moderate/severe]) and the use of an aortic clamp. A propensity score estimated probability of clamp use was based on 45 risk factors. Multiple logistic regression models measured the association between outcomes—death, stroke, myocardial infarction, and major adverse cardiac and cerebrovascular events (MACCE)—and the primary variables (grade and clamp use), adjusted for propensity score.

Results

Grade was available in 4278 patients. Patients with grade 3 to 5 AAA had an increased risk of death (adjusted odds ratios (AOR) 3.11; P < 0.001), stroke (AOR 2.12; P < 0.001), and MACCE (AOR 2.58; P < 0.001). Aortic clamping (any clamp, all grades) led to a higher risk of stroke (AOR 2.77; P = 0.032). EU altered aortic manipulation in 530 patients (12.4%). In this group, patients with high grade aortas had similar rates of death, stroke or MACCE, when compared with patients with low-grade aortas.

Conclusions

EU alters surgical strategy. Patients with grade 3 to 5 AAA are at increased risk of death, stroke, and MACCE compared with patients with grade 1 to 2 AAA. Clamping the aorta (any grade) increases the risk for stroke. Aortic clamping should be avoided in patients with grade 3 to 5 AAA, but EU may minimize morbidity and mortality if a clamp must be used.

Enhanced intra-operative grading of ascending aorta atheroma by epiaortic ultrasound vs echocardiography

AIMS

Intra-operative grading of atheromatous plaques in the ascending aorta by epiaortic ultrasound (EAU) and transesophageal echocardiography (TEE) in patients who have undergone CABG.

METHODS AND RESULTS

Sixty patients scheduled for elective CABG were prospectively enrolled to undergo intra-operative TEE and EAU ultrasound scanning of the ascending aorta. The ascending aorta was divided into three sections; proximal, middle and distal, and four segments; anterior, posterior, medial and lateral. Degree of atherosclerosis was graded according to a modified Montgomery scale. Epiaortic ultrasound was unable to provide images for a reliable assessment in 56 areas (7.7%; 56/720) vs 322 non-visualized areas by TEE (44.7%; 298/720) (p<0.01). Out of 563 areas that scored >or=2, EAU visualized 379/720 areas (52.6%), whereas TEE visualized 184/720 areas (25.5%) (p<0.01). EAU mean scores were significantly higher for the mid (p=0.0001) and distal (p=0.05) sections and for the posterior segment (p<0.01) vs TEE. TEE had a higher mean score than EAU in the anterior segment. When all EAU areas were grouped the posterior segment reached a significantly higher mean score (p<0.01), and the anterior segment was the second mostly diseased.

CONCLUSIONS

EAU is the intra-operative investigation of choice because it allowed a detailed grading of atheromatous lesions over the entire length of the ascending aorta. Accurate grading by TEE was restricted only to those areas that could be sufficiently visualized. TEE has a reduced power of investigation that limits its use, especially in the distal ascending aorta, a site of great surgical manipulation.

The influence of epiaortic ultrasonography on intraoperative surgical management in 6051 cardiac surgical patients

BACKGROUND

Intraoperative echocardiography has become a mainstay monitor of cardiac function and a popular diagnostic tool in patients undergoing cardiac procedures. Previous reports suggest that epiaortic ultrasonography (EU) is superior to transesophageal echocardiography and manual palpation in identifying ascending aortic atheroma. Its impact on surgical decision making has not been thoroughly investigated, however.

METHODS

We retrospectively analyzed the medical records of 6051 consecutive patients who underwent EU of their ascending aorta during cardiac operations between 1996 and 2006 to determine a potential impact on intraoperative surgical decision making. Aortic atheroma was graded according to standard classification. Neurologic complications were evaluated according to the Society of Thoracic Surgeon definition for stroke and transient ischemic attack (TIA).

RESULTS

The overall impact of EU on surgical decision making was 4.1% and included a change in the technique for inducing cardiac arrest in 1.8%, aortic atherectomy or replacement surgery in 0.8%, requirement for off-pump coronary artery bypass grafting (CABG) in 0.6%, avoidance of aortic cross-clamping and use of ventricular fibrillatory arrest in 0.5%, change in arterial cannulation site in 0.2%, or avoidance of aortic cannulation in 0.2%. The greatest affect of EU was observed in patients undergoing combined CABG with aortic/mitral valve procedures (6.7%). The smallest impact was seen in patients undergoing mitral valve operations (1.4%). Aortic atheroma was more frequent on the anterior aspect of the aorta (n = 171) in patients with a change in surgical plan than on the posterior aspect (n = 78). The overall stroke rate was lower in patients with intraoperative EU compared with all patients undergoing surgical procedures.

CONCLUSIONS

Epiaortic ultrasonography is a useful technique to detect ascending aortic atheroma, has a significant impact on surgical decision making in more than 4% of cardiac surgical patients, and might result in improved perioperative neurologic outcome.

Atherosclerosis of the ascending aorta as a major determinant of the outcome of cardiac surgery

Epiaortic ultrasonography has high sensitivity for the detection of atherosclerosis. In several studies, the technique has identified atherosclerosis of the ascending aorta as the major risk factor for stroke after cardiac surgery. The level of risk depends on the presence, location and extent of disease when the ascending aorta is surgically manipulated. This knowledge enables clinicians to focus on the diagnostic and surgical technique and to consider the various options. Routine use of intraoperative epiaortic ultrasonography should be applied so that surgical manipulation of the ascending aorta can be reduced or, if possible, avoided in patients with atherosclerosis of the ascending aorta. Alternatively, if major manipulation such as clamping must be performed in the presence of severe atherosclerosis, the use of intra-aortic filters could be considered.