Intraoperative transesophageal echocardiography and epiaortic ultrasound for assessment of atherosclerosis of the thoracic aorta

The Rationalisation of Intra-Operative Imaging During Cardiac Surgery: A Systematic Review

INTRODUCTION

One critical complication of cardiac surgery is cerebrovascular accidents (CVAs). Ascending aorta atherosclerosis poses a significant risk of embolisation to distal vessels and to cerebral arteries. Epi-aortic ultrasonography (EUS) is thought to offer a safe, high-quality accurate visualisation of the diseased aorta to guide the surgeon on the best surgical approach to the planned procedure and potentially improve neurological outcomes post-cardiac surgery.

METHOD

The authors conducted a comprehensive search of PubMed, Scopus and Embase. Studies that reported on epi-aortic ultrasound use in cardiac surgery were included. Major exclusion criteria were: (1) abstracts, conference presentations, editorials, literature reviews; (2) case series with <5 participants; (3) epi-aortic ultrasound in trauma or other surgeries.

RESULTS

A total of 59 studies and 48,255 patients were included in this review. Out of the studies that reported patient co-morbidities prior to cardiac surgery, 31.6% had diabetes, 59.5% had hyperlipidaemia and 66.1% had a diagnosis of hypertension. Of those that reported significant ascending aorta atherosclerosis found on EUS, this ranged from 8.3% of patients to 95.2% with a mean percentage of 37.8%. Hospital mortality ranged from 7% to 13%; four studies reported zero deaths. Long-term mortality and stroke rate varied significantly with hospital duration.

CONCLUSION

Current data have shown EUS to have superiority over manual palpation and transoesophageal echocardiography in the prevention of CVAs following cardiac surgery. Yet, EUS has not been implemented as a routine standard of care. Extensive adoption of EUS in clinical practice is warranted to aid large, randomised trials before making prospective conclusions on the efficacy of this screening method.

Predictors and Outcomes of Stroke After Isolated Coronary Artery Bypass Grafting. A Single-Center Experience in 20,582 Patients

OBJECTIVE

Stroke remains a devastating complication after cardiac surgical procedures despite perioperative monitoring and management advances. This study aimed to determine the predictors of stroke in a large, contemporary coronary artery surgery population.

DESIGN

Patient data were analyzed retrospectively.

SETTING

This single-center study was performed in the Catharina Hospital (Eindhoven).

PARTICIPANTS

All patients who underwent isolated coronary artery bypass grafting (CABG) between January 1998 and February 2019 were included.

INTERVENTIONS

Isolated CABG.

MEASUREMENTS AND MAIN RESULTS

The primary endpoint was a postoperative stroke, defined according to the international updated definition for stroke. Logistic regression was performed to retrieve variables associated with postoperative stroke. A total of 20,582 patients underwent CABG during the period of the study. Stroke was observed in 142 patients (0.7%), of which 75 (52.8%) occurred during the first 72 hours. The incidence of postoperative stroke declined over the years. A significantly higher 30-day mortality rate was seen in patients with stroke (20.4%) compared with 1.8% in the rest of the population; p < 0.001. Multivariate logistic regression analysis showed age, peripheral arterial disease, reexploration for bleeding, perioperative myocardial infarction, and year of surgery as independent predictors for stroke. Patients with postoperative stroke had worse long-term survival (log-rank p < 0.001). Cox regression analysis revealed postoperative stroke (odds ratio 2.13 [1.73-2.64)) as an independent predictor of late mortality.

CONCLUSIONS

Stroke after CABG is associated with high early and late mortality. Age, peripheral vascular disease, and the year of surgery were associated with postoperative stroke.

Cardiopulmonary Bypass Emergencies and Intraoperative Issues

Cardiopulmonary bypass (CPB) is a complex biomechanical engineering undertaking and an essential component of cardiac surgery. However, similar to all complex bioengineering systems, CPB activities are prone to a variety of safety and biomechanical issues. In this narrative review article, the authors discuss the preventative and intraoperative management strategies for a number of intraoperative CPB emergencies, including cannulation complications (dissection, malposition, gas embolism), CPB equipment issues (heater-cooler failure, oxygenator issues, electrical failure, and tubing rupture), CPB circuit thrombosis, medication issues, awareness during CPB, and CPB issues during transcatheter aortic valve replacement.

Impact of High-Resolution Epiaortic Ultrasonographic Imaging on Evaluating Aortic Wall Pathology

There has been no definitive method, other than pathological findings, to identify the degeneration of the tunica media in the aortic wall (TM). We describe how high-resolution intraoperative epiaortic ultrasonographic imaging identifies changes in the TM of patients with aortic dissection. This method shows great promise in facilitating presymptomatic diagnoses of various aortic wall pathologies.

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.

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.

Routine preoperative aortic computed tomography angiography is associated with reduced risk of stroke in coronary artery bypass grafting: a propensity-matched analysis

OBJECTIVES

The aim of this study was to determine stroke rates in patients who did or did not undergo routine computed tomography angiography (CTA) aortic imaging before isolated coronary artery bypass grafting (CABG).

METHODS

We conducted a retrospective analysis of a prospectively maintained single-centre registry. Between 2009 and 2016, a total of 2320 consecutive patients who underwent isolated CABG at our institution were identified. Propensity score matching was used to create a paired cohort of patients with similar baseline characteristics who did (CTA cohort) or did not (non-CTA cohort) undergo preoperative aortic CTA. The primary end point of the analysis was in-hospital stroke.

RESULTS

In 435 propensity score-matched pairs, stroke occurred in 4 patients (0.92%) in the CTA cohort and in 14 patients (3.22%) in the non-CTA cohort (P = 0.017). Routine preoperative aortic CTA was associated with a significantly reduced risk of in-hospital stroke [relative risk 0.29, 95% confidence interval (CI) 0.09-0.86; P = 0.026; absolute risk reduction 2.3%, 95% CI 0.4-4.2; P = 0.017; number needed to treat = 44, 95% CI 24-242].

CONCLUSIONS

A preoperative screening for atheromatous aortic disease using CTA is associated with reduced risk of stroke after CABG. The routine use of preoperative aortic CTA could be applied so that surgical manipulation of the ascending aorta can be selectively reduced or avoided in patients with atheromatous aortic disease.

Timing of Recognition for Perioperative Strokes Following Cardiac Surgery

INTRODUCTION

More than half of reported perioperative strokes following cardiac surgery are identified beyond postoperative day one. The objective of our study was to determine preoperative and intraoperative factors that are associated with stroke following cardiac surgery and to identify factors that may contribute delayed recognition of perioperative stroke.

METHODS

Patients undergoing coronary artery bypass surgery or isolated valve surgery from January 2, 2015 to April 28, 2017 at an academic health system were identified from the Society of Thoracic Surgeons Registry. We determined preoperative and intraoperative factors associated with perioperative stroke. Two neurologists performed retrospective chart reviews on perioperative stroke patients to determine the last seen well time and the stroke cause.

RESULTS

During the study period, 2795 patients underwent coronary artery bypass surgery or isolated valve surgery (mean age 64 ± 11 years, 71% male, 72% Caucasian, 9% history of stroke), of which 43 (1.5%) had a perioperative stroke; 31 (72%) patients had an embolic mechanism of stroke based on neuroimaging. In multivariable analysis, perioperative strokes were independently associated with increasing age (OR 1.04, 95% 1.01-1.07), history of stroke (OR 2.73, 95% CI 1.47-5.06), and history of thoracic aorta disease (OR 3.36, 95% CI 1.16-9.71). Strokes were identified after postoperative day one in 32 (74%) patients of which 26 (81%) had a preoperative last seen well time.

CONCLUSION

Given the high frequency of preoperative last seen well time in perioperative stroke patients who are identified after postoperative day one, delayed stroke recognition may contribute to the bimodal distribution in timing of perioperative stroke. Frequent neurological monitoring within 24 hours after CABG or isolated valve surgery should be considered for all patients undergoing cardiac surgery, particularly elderly patients and those with a history of stroke or thoracic aorta disease, to improve early stroke recognition.

Atherosclerotic plaque detected by transesophageal echocardiography is an independent predictor for all-cause mortality

Atherosclerotic lesions in the great arteries are frequent findings in the elderly. Numerous studies have shown their strong predictive value for cardiovascular disease, embolic events, and mortality. We sought to determine the risk of all-cause mortality depending on the localization of plaques in the thoracic aorta evaluated by transesophageal echocardiography (TEE). A total of 2,054 patients (median age 65 years, interquartile range 52–73; 58% men) who underwent a TEE examination between 01/2007 and 03/2015 were retrospectively analyzed. For each patient, the presence of atherosclerotic lesions in the ascending aorta, the aortic arch, and in the descending aorta, as well as cardiovascular risk factors and survival were documented. Median follow-up period was 48 months (interquartile range 38–58). Multivariate Cox regression analysis indicated plaque in the ascending aorta (HR of 1.36, 95% CI 1.01–1.83, P = 0.046), the aortic arch (HR of 1.78, 95% CI 1.29–2.45, P < 0.001), the descending aorta (HR of 2.01, 95% CI 1.54–2.77, P < 0.001), and plaque in any part of the thoracic aorta (HR of 1.84, 95% CI 1.42–2.4, P < 0.001), as independent predictors for all-cause mortality after adjusting for age, sex, arterial hypertension, hyperlipidemia, smoking, and diabetes. In this study, we could demonstrate that more than mild plaque at any site of the thoracic aorta predicts all-cause mortality. Assessment of atherosclerotic lesions in all segments of the thoracic aorta should be part of every routine TEE examination.

Epiaortic Ultrasound for Assessment of Intraluminal Atheroma; Insights from the REGROUP Trial

OBJECTIVES

To assess the use of epiaortic ultrasound in contemporary cardiac surgery, as well as its impact on surgical cannulation strategy and cerebrovascular events.

DESIGN

Epiaortic ultrasound data was prospectively collected in the Randomized Endovein Graft Prospective (REGROUP) trial (VA Cooperative Studies Program #588, ClinicalTrials.gov, NCT01850082), which randomized 1,150 coronary artery bypass graft patients between 2014 and 2017 to endoscopic or open-vein graft harvest.

SETTING

Sixteen cardiac surgery programs within the Veterans Affairs Healthcare System with expertise at performing endoscopic vein-graft harvesting.

PARTICIPANTS

Veterans Affairs patients, greater than 18 years of age, undergoing elective or urgent coronary artery bypass grafting with cardiopulmonary bypass and cardioplegic arrest with at least one planned saphenous vein graft were eligible for enrollment.

INTERVENTIONS

Epiaortic ultrasound was performed by the surgeon using a high frequency (>7 MHz) ultrasound transducer. Two-dimensional images of the ascending aorta in multiple planes were acquired before aortic cannulation and cross-clamping.

MEASUREMENTS AND MAIN RESULTS

Epiaortic ultrasound was performed in 34.1% (269 of 790) of patients in REGROUP. Among these patients, simple intraluminal atheroma was observed in 21.9% (59 269), and complex intraluminal atheroma comprised 2.2% (6 of 269). The aortic cannulation or cross-clamp strategy was modified based on these findings in 7.1% of cases (19 of 269). There was no difference in stroke between patients who underwent epiaortic ultrasound and those who did not (1.9% v 1.2% p = 0.523).

CONCLUSIONS

Despite current guidelines recommending routine use of epiaortic ultrasound (IIa/B) to reduce the risk of stroke in cardiac surgery, in this contemporary trial, use remains infrequent, with significant site-to-site variability.

Impact of Aortic Atherosclerosis Burden on Outcomes of Surgical Aortic Valve Replacement

BACKGROUND

Epiaortic ultrasound detects and localizes ascending aortic atherosclerosis. In this analysis we investigated the association between epiaortic ultrasound-based atheroma grade during surgical aortic valve replacement (SAVR) and perioperative adverse outcomes.

METHODS

SAVR patients in a randomized trial of 2 embolic protection devices underwent a protocol-defined 5-view epiaortic ultrasound read at a core laboratory. Aortic atherosclerosis was quantified with the Katz atheroma grade, and patients were categorized as mild (grade I-II) or moderate/severe (grade III-V). Multivariable logistic regression was used to estimate associations between atheroma grade and adverse outcomes, including death, clinically apparent stroke, cerebral infarction on diffusion-weighted magnetic resonance imaging, delirium, and acute kidney injury (AKI) by 7 and 30 days.

RESULTS

Precannulation epiaortic ultrasound data were available for 326 of 383 randomized patients (85.1%). Of these, 106 (32.5%) had moderate/severe Katz atheroma grade at any segment of the ascending aorta. Although differences in the composite of death, stroke, or cerebral infarction on diffusion-weighted magnetic resonance imaging by 7 days were not statistically significant, moderate/severe atheroma grade was associated with a greater risk of AKI by 7 days (adjusted odds ratio, 2.63; 95% confidence interval, 1.24-5.58; P = .01). At 30 days, patients with moderate/severe atheroma grade had a greater risk of death, stroke, or AKI (adjusted odds ratio, 1.97; 95% confidence interval, 1.04-3.71; P = .04).

CONCLUSIONS

Moderate/severe aortic atherosclerosis was associated with an increased risk of adverse events after SAVR. Epiaortic ultrasound may serve as a useful adjunct for identifying patients who may benefit from strategies to reduce atheroembolic complications during SAVR.

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.

Echocardiographic imaging options in ovine research subjects

OBJECTIVES

To determine the feasibility of acquiring quality transesophageal (TEE), epicardial (EE), and intracardiac (ICE) echocardiographic images in ovine subjects and to discuss the merits of each technique with a focus on ICE image acquisition.

ANIMALS

Eleven male castrated Dorset adult sheep.

METHODS

Transesophageal echocardiography was performed under general anesthesia. Epicardial echocardiography was performed as part of an open chest (thoracotomy or sternotomy) experiment. Subjects were recovered with permanent jugular vein indwelling catheter and ICE from this approach was described. Feasibility of each technique was qualitatively assessed based on subjective image quality from three images for each image plane in each sheep.

RESULTS

Transesophageal echocardiography was technically challenging and did not provide adequate image quality for consistent interpretation. Epicardial echocardiography and ICE had more favorable results with ICE demonstrating unique benefits for post-operative serial monitoring.

CONCLUSIONS

Epicardial echocardiography and ICE were effective imaging techniques. Epicardial echocardiography required the least specialized training but was considered to have limited feasibility due to its requirement for an open chest procedure. Even with the necessity for permanent indwelling jugular cannulation, ICE was the least invasive of the three imaging techniques and potentially the most practical approach for chronic studies by minimizing post-operative stress. Transesophageal echocardiography was not a feasible technique in this study.

Atheromatous embolization

Atheromatous embolization is a multisystem disease complicating advanced atherosclerosis. It occurs most often as a complication of angiography, an endovascular procedure or cardiovascular surgery. Atheromatous embolization can present in a subtle manner where it is often under-recognized, or with catastrophic results including myocardial infarction, strake or acute renal failure. It may mimic other disease processes and often goes underdiagnosed and undertreated. A high clinical suspicion is the key to diagnosis. Atheromatous embolization results in significant morbidity and mortality; therefore, early recognition followed by aggressive management may help to prevent end-organ damage and improve overall clinical outcomes. Management strategies should include risk factor modification, prevention of further insults by discontinuing or avoiding predisposing factors, supportive treatment and interventional or surgical approaches to remove the atheroembolic source. Atheromatous embolization is expected to increase as our population ages and the epidemics of diabetes mellitus and obesity increase.

The Impact of Intraoperative Echocardiography on Clinical Outcomes Following Adult Cardiac Surgery

Over the past 30 years, intraoperative echocardiography has become an invaluable diagnostic tool and monitor of cardiac performance for the management of cardiac surgical patients. The essential information provided by intraoperative echocardiography regarding hemodynamic management, cardiac valve function, congenital heart lesions, and great vessel pathology has contributed to its widespread popularity. Numerous investigations have been conducted in an attempt to specifically demonstrate a beneficial impact of intraoperative echocardiography in cardiac surgery. However, there is a relative paucity of data derived from prospective trials in which the use of intraoperative echocardiography has been randomized among various cardiac surgical patient populations to formally ascertain, rather than simply infer, its putative impact on perioperative decision-making and clinical outcomes. Ironically, the popularity of intraoperative echocardiography has imposed ethical limitations on performing randomized trials in patient populations for whom significant benefit has been previously inferred. Nonetheless, significant evidence has been published to support its almost universal acceptance as an important perioperative diagnostic tool and monitor for cardiac surgical patients. This review focuses on the impact of intraoperative echocardiography on clinical outcomes in the more common adult cardiac surgical scenarios, including coronary artery bypass graft surgery, mitral and aortic valve surgery, and in evaluating the intrathoracic aorta.

3-D Imaging for Aortic Plaque Assessment

Stroke and neurologic dysfunction continue to complicate cardiac surgery despite improvements in cardiopulmonary bypass. Intra-aortic plaque disrupted during aortic manipulation is a known risk factor contributing to neurologic complications; therefore, avoidance of these plaques during aortic manipulation is important. Intraoperative epiaortic echocardiography, with its high sensitivity and specificity, has become the modality of choice for detecting plaque within the aorta during cardiac surgery and is superior to either transesophageal echocardiography or aortic palpation for this purpose. Recently the matrix x4 three-dimensional (3D) ultrasound probe (Philps Medical Systems) was introduced allowing both real time 3D imaging and electrocardiography-gated “full volume” imaging, which essentially acquires a larger image but requires 8 cardiac cycles. Modification of our routine scanning technique was required, employing a saline (about 30 mL) filled sterile sheath secured with a sterile elastic band (creating a saline pocket). There appears little difference in the sensitivity of either 2D or 3D imaging to detect plaque within the aorta. We found that live 3D was superior to 2D imaging in identifying, localizing, and defining the true extent of plaque in the aorta.

Stroke associated with coronary artery bypass grafting

While coronary artery bypass grafting (CABG) has been playing a significant role in the revascularization for ischemic heart disease, neurological complications associated with CABG have been a primary concern. Stroke, although the incidence is low, is one of the most devastating complication of CABG. Many studies have identified the risk factors for stroke with CABG, such as prior stroke, carotid artery stenosis, aortic atherosclerosis, atrial fibrillation and cardiopulmonary bypass. Various rational approaches focusing on individual risk factor have been proposed for the stroke. Prophylactic carotid revascularization is an important strategy, and the diagnosis of carotid stenosis has to be established correctly. Prevention of emboli from aortic plaque is also an essential issue. Intraoperative monitoring with transesophageal or epiaortic ultrasound is useful to identify mobile atheromatous plaques and to select appropriate aortic manipulations. Maintenance of cerebral blood flow and blood pressure during cardiopulmonary bypass might be critical issues. Besides, there are conflicting two opinions regarding off-pump CABG; one supports an efficiency for the prevention of stroke while the other advocates no effect. This discrepancy might be explained by the difference of the risk of stroke in the population of the individual study and by the variation of the percentage of aortic clamping or aortic anastomosis in each study. Pharmaceutical therapies such as statin, preventive medication for atrial fibrillation, or antiplatelet are promising methods. Although it is hard to decrease the incidence of the stroke with any single countermeasure, sustained effort should be continued to overcome the stroke associated with CABG.

Reconstruction of the descending thoracic aorta by multiview compounding of 3-D transesophageal echocardiographic aortic data sets for improved examination and quantification of atheroma burden

A robust and efficient approach to reconstruction of the descending thoracic aorta from contiguous 3-D transesophageal echocardiographic (TEE) images is proposed. An ad hoc image acquisition protocol was designed to acquire ordered and partially overlapped 3-D TEE data sets, followed by dedicated image processing to align and fuse all acquired data sets. Alignment strategy implemented pairwise rigid registration guided by a priori knowledge, and it was validated using artificially misaligned images. Image fusion was finally performed to enable visualization and analysis of extended field-of-view of the acquired aorta. The application of different fusion techniques was also investigated. The method was applied to a population of 17 consecutive patients. Qualitative and quantitative results supported the feasibility and accuracy of the proposed approach. In a clinical scenario, its application could allow the quantitative assessment of aortic plaque burden in the descending thoracic aorta from 3-D TEE images.

Bad aorta

As its outcomes improve, cardiac surgery has been performed on more and more cases which were previously considered to be difficult to deal with. However, there are still a number of problems to be solved regarding surgery on patients with severe sclerotic lesions in the ascending aorta, which we collectively call "bad aorta". Concerning a preoperative assessment of the ascending aorta, our report revealed no relationship between the severity of calcification detected with a preoperative non-enhanced CT and the aortic lesion found during the surgery. Meanwhile, an intraoperative epiaortic ultrasound enables us to make high-quality evaluations of the aorta without imposing much burden on the patient. This modality may be essential for cardiac surgery. As for surgical management for bad aorta, quite a few methods have been reported to this point, but the overall operative mortality rate and cerebrovascular accident rate are relatively high, at a little <10 %, respectively. With the recent cross-clamping method under short-term total circulatory arrest (TCA), however, the results are much better; these rates total around 5 %. Further improvement is expected in the outcome of cardiac surgery on bad aorta cases by establishing a modality to evaluate sclerotic lesions in the ascending aorta with epiaortic ultrasound and by selecting a proper procedure for each case.

Effects of single aortic clamping versus partial aortic clamping techniques on post-operative stroke during coronary artery bypass surgery

BACKGROUND

The aim of this study was to compare the effects of single-clamping and partial-clamping techniques on postoperative stroke during coronary artery bypass surgery.

METHODS

Between December 2008 and December 2012, 2 000 patients who underwent coronary artery bypass grafting in two hospitals were analysed. Post-operative neurological complications were analysed retrospectively in these patients. The cases were divided into two groups: in group 1, 1 500 patients were analysed, in whom proximal anastomosis was performed with partial clamping in a beating heart (n = 1 500, 846 male, 654 female; mean age 63.25 ± 5.72 years; range 43-78 years). In group 2, 500 patients were analysed, in whom proximal anastomosis had been performed by other surgical teams in another hospital, with cross clamping in a resting heart with cardioplegia (n = 500, 296 male, 214 female; mean age 64.83 ± 8.12 years; range 41-81 years). During 30 days post-operatively, neurological deficits, stroke incidence and the relationship of the clinical situation to mortality were analysed.

RESULTS

For both groups, patients were similar in terms of patient characteristics. In group 2, cross-clamp duration and perfusion time were longer; however, time of hospital stay was similar in the two groups. Post-operative stroke was seen in 26 patients in group 1 (1.73%) and in nine in group 2 (1.8%). The difference between the two groups was not statistically significant (p = 0.92). All stroke patients were over the age of 55 years. Seven of the stroke patients died (21.1%). In total, 31 patients died because of multiple organ failure in the postoperative 30 days (group 1: 1.6%; group 2: 1.4%) (p = 0.91). Smoking, diabetes mellitus, hypertension, atrial fibrillation, peripheral vascular disease and hypercholesterolaemia were found to be factors that affected stroke development. Mean duration of hospital stay was 5.1 ± 2.8 days in group 1 and 4.9 ± 3.6 days in group 2 and the difference between the two groups was not statistically significant (p = 0.46).

CONCLUSION

In patients without plaques in the aorta, performing partial clamping did not increase stroke incidence.

Management of carotid disease in patients undergoing coronary artery bypass surgery: is it time to change our approach?

PURPOSE OF REVIEW

The management of concurrent severe carotid and coronary disease is a subject of ongoing debate in the absence of randomized clinical trials. Amidst the growing controversy, the clinician has to carefully tailor the best strategy for a given patient based on neurologic and cardiac symptoms. This review aims to compile current evidence in this area to help plan strategies for the optimal management of coexisting severe carotid and coronary disease.

RECENT FINDINGS

Carotid revascularization with carotid endarterectomy (CEA) or stenting (CAS) is frequently performed in conjunction with coronary artery bypass surgery (CABG) in the United States for asymptomatic carotid disease. The risk of perioperative stroke with unilateral asymptomatic 70-99% carotid stenosis is likely small based on several observational data. Moreover, the risk associated with both staged and combined CEA-CABG procedures in the asymptomatic population may outweigh any benefit. Carotid artery stenting is an alternative option in patients with severe coronary disease who are considered 'high risk' for CEA. Neurologically symptomatic patients require carotid revascularization prior to or in conjunction with CABG surgery. Ultimately, the choice of carotid revascularization or conservative management will depend on clinical characteristics, anatomy, and local expertise.

SUMMARY

Severe carotid disease in the CABG population is often unilateral and asymptomatic. Based on the available data, conservative carotid therapy in the low-risk asymptomatic individuals is likely the best treatment option. Carotid revascularization may be justified in symptomatic or high-risk patients such as those with contralateral carotid occlusion or bilateral severe stenosis.

Branch-first aortic arch replacement with no circulatory arrest or deep hypothermia

BACKGROUND

For aortic arch surgery, the potential risks of deep hypothermic circulatory arrest with or without antegrade cerebral perfusion have been widely documented. We hereby describe our early experience with a "branch-first continuous perfusion" technique that, by avoiding deep hypothermia and circulatory arrest, has the potential to reduce morbidity and mortality.

METHODS

Arterial perfusion is peripheral using femoral and axillary inflows. Disconnection of each arch branch, and anastomosis to the trifurcation graft, proceeds sequentially from the innominate to the left subclavian artery, with continuous perfusion of the heart and viscera by lower body and brain by upper body arterial return. After the descending aorta is clamped, the debranched arch may then be replaced and connected to the ascending aorta before the common stem of the trifurcation graft is joined to the arch graft. Thirty patients underwent this technique. Twelve patients were operated on for aortic dissection and the remainder for aneurysms.

RESULTS

With experience, minimum pump temperature rose from 16°C to 34°C. There was 1 (3.3%) death, and 2 (6.7%) patients had neurological dysfunction. Extubation was achieved within 24 hours in 12 (40%) patients, whereas 14 (47%) left the intensive care unit within 2 days. Ten (33%) patients were discharged from the hospital within 7 days. Eight (27%) patients required no transfusion of blood or blood products.

CONCLUSIONS

This technique brings us closer to the goal of arch surgery without cerebral or visceral circulatory arrest and the morbidity of deep hypothermia. Early results are encouraging.

Aortic atheroma and adverse cerebral outcome: risk, diagnosis, and management options

Aortic atheromatous disease is a common finding in the patient presenting for cardiac surgery. Adverse neurologic outcome has been closely linked to the extent of aortic atherosclerosis. In order to optimize perioperative outcomes, the location and severity of disease needs accurate characterization using multimodal techniques. Although various preoperative radiographic techniques have variably identified patients with significant atheroma, intraoperative echocardiographic imaging has proven most useful in localizing and characterizing the degree of aortic atheroma. Epiaortic assessment of the ascending aorta has been utilized in guiding surgical modifications and interventions aimed at reducing the risk of neurologic injury. Although no particular technique has been definitely studied, avoidance of the identifiable atheromatous aortic region has been a main feature of the various modifications employed to optimize neurologic outcome after cardiac surgery.

Meta-analysis of the diagnostic accuracy of transesophageal echocardiography for assessment of atherosclerosis in the ascending aorta in patients undergoing cardiac surgery

BACKGROUND

Stroke after cardiac surgery may be caused by emboli emerging from an atherosclerotic ascending aorta (AA). Epiaortic ultrasound scanning (EUS), the current 'gold' standard for detecting AA atherosclerosis, has not gained widespread use because there is a lack of optimized ultrasound devices, it lengthens the procedure, it endangers sterility, and there is a false belief by many surgeons that palpation is as sensitive as EUS. Furthermore there is no clear evidence proving that the use of epiaortic scanning changes outcome in cardiac surgery. Various researchers investigated the ability of transesophageal echocardiography (TEE) to discriminate between the presence and absence of AA atherosclerosis. It is acknowledged that TEE has limited value in this, but it has never been supported by a meta-analysis estimating the true diagnostic accuracy of TEE based on all quantitative evidence. We aimed to do this using state-of-the-art methodology of diagnostic meta-analyses.

METHODS

We searched multiple databases for studies comparing TEE vs. EUS for detection of atherosclerosis. A random-effects bivariate meta-regression model was used to obtain summary estimates of sensitivity and specificity, incorporating the correlation between sensitivity and specificity as well as covariates to explore heterogeneity across studies.

RESULTS

We extracted six studies with a total of 346 patients, of whom 419 aortic segments were analyzed, including 100 segments with atherosclerosis [median prevalence 25% (range 17-62%)]. Summary estimates of sensitivity and specificity were 21% (95% CI 13-32%) and 99% (96-99%), respectively.

CONCLUSIONS

Because of the low sensitivity of TEE for the detection of AA atherosclerosis, a negative test result requires verification by additional testing using epiaortic scanning. In case of a positive test result, AA atherosclerosis can be considered as present, and less manipulative strategies might be indicated.

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.