Paul A. Tunick

Protruding aortic atheromas predict stroke in elderly patients undergoing cardiopulmonary bypass: Experience with intraoperative transesophageal echocardiography

Protruding atheromas of the aortic arch identified by transesophageal echocardiography have been implicated as a cause of stroke in elderly patients. One hundred thirty patients greater than or equal to 65 years of age were studied with intraoperative transesophageal echocardiography to detect aortic arch protruding atheromas and determine if these patients were at higher risk for perioperative stroke. Protruding atheromas were identified in 23 (18%) of 130 patients. In 19 (83%) of these 23 patients, palpation of the aortic arch at operation did not identify significant abnormalities. Five patients (4%) had perioperative stroke. Logistic regression identified aortic arch atheroma as the only historical or procedural variable that was predictive of stroke (odds ratio 5.8, 95% confidence interval 1.2 to 27.9, p less than 0.03). A history of peripheral or cerebrovascular disease, presence of aortic calcification, cardiac risk factors, age and duration of cardiopulmonary bypass did not predict stroke. In contrast, patients with protruding atheromas with mobile components were at highest risk. There were 3 (25%) of 12 patients with a mobile atheroma who had a stroke versus 2 (2%) of 118 patients without a mobile atheroma (chi-square = 10.3, p = 0.001). Displacement and detachment of the frail, protruding atherosclerotic material by aortic arch cannulation or by the high pressure jet emanating from the cannula tip may play an important role in the creation of embolization and stroke.

Protruding atheromas in the thoracic aorta and systemic embolization.

OBJECTIVE To determine whether protruding atheromas in the thoracic aorta are a risk factor for systemic embolization. DESIGN Case-control study. SETTING A referral hospital. PATIENTS A total of 122 patients with a history of stroke, transient ischemic attack, or peripheral emboli and an equal number of age- and sex-matched control patients. MEASUREMENTS Evaluation using transesophageal echocardiography was done in case patients to detect protruding atheromas in the thoracic aorta and in control patients for cardiac indications other than emboli. MAIN RESULTS Matched logistic regression showed that the presence of protruding atheromas was strongly related to the occurrence of embolic symptoms (odds ratio, 3.2; 95% Cl, 1.6 to 6.5; P less than 0.001). Furthermore, atheromas with mobile components were present only in case patients. When known risk factors for stroke (hypertension and diabetes) were added to the model, the presence of protruding atheromas remained an independent risk factor for embolic symptoms (odds ratio, 3.8). Hypertension was also independently associated with embolic symptoms (odds ratio, 2.7), but diabetes was not (odds ratio, 1.0). CONCLUSION Protruding atheromas in the thoracic aorta can be detected by transesophageal echocardiography and should be considered as a cause of strokes, transient ischemic attacks, and peripheral emboli.

Surgical Left Atrial Appendage Ligation Is Frequently Incomplete: A Transesophageal Echocardiographic Study

OBJECTIVES This study sought to determine the incidence of incomplete ligation of the left atrial appendage (LAA) during mitral valve surgery. BACKGROUND Ligation of the LAA to prevent future thromboembolic events is commonly performed during mitral surgery. However, success in completely excluding the appendage from the circulation has never been systematically assessed. METHODS Using transesophageal Doppler echocardiography, we studied 50 patients who underwent mitral valve surgery and ligation of the LAA. Thirty patients were studied immediately postoperative, and 20 patients were studied 6 days to 13 years after surgery. Incomplete ligation was detected by demonstrating a color jet traversing the separation between the left atrial body and appendage. RESULTS Transesophageal echocardiography detected incomplete LAA ligation in 18 of 50 (36%) patients. The incidence of incomplete ligation was not significantly different between patients studied immediately postoperative and patients studied at various times after surgery. Type of mitral surgery (repair vs. replacement), operative approach (sternotomy vs. port access), left atrial size or degree of mitral regurgitation did not significantly correlate with the incidence of incomplete appendage ligation. However, the power to detect a significant difference in left atrial size was only 64%. Spontaneous echo contrast or thrombus was identified within appendages in 9 of 18 (50%) patients with incomplete ligation, while 4 of these 18 (22%) patients had thromboembolic events. CONCLUSIONS Surgical LAA ligation is frequently incomplete. The similar incidence of incomplete ligation detected immediately postoperative and at various times thereafter suggest that this results from an intraoperative phenomenon rather than from gradual dehiscence of sutures over years. The incidence of incomplete left atrial ligation was unrelated to type of surgery, surgical approach, left atrial size or degree of mitral regurgitation. Residual communication between the incompletely ligated appendage and the left atrial body may produce a milieu of stagnant blood flow within the appendage and be a potential mechanism for embolic events.

Protruding atherosclerotic plaque in the aortic arch of patients with systemic embolization: A new finding seen by transesophageal echocardiography

Patients with unexplained stroke or other embolic phenomena are often referred for echocardiography. The aortic arch is not usually visualized in detail during routine echocardiography; however, with the introduction of transesophageal echocardiography, this area may be seen with great resolution. We recently studied three patients who had embolic events, and transesophageal echocardiography showed a new and unexpected finding; large, protrusive plaques in the aortic arch and descending aorta, which have mobile projections that move freely with the blood flow. These lesions could be responsible for embolic syndromes, especially after catheter manipulation in the aorta.

High risk for vascular events in patients with protruding aortic atheromas: A prospective study

OBJECTIVES The purpose of this study was to prospectively evaluate the risk of vascular events in patients with protruding aortic atheromas. BACKGROUND Protruding atheromas of the thoracic aorta have been shown to be associated with embolic disease in previous retrospective studies. METHODS During a 1-year period, 521 patients had transesophageal echocardiography. Of these, 42 patients had protruding atheromas and no other source of emboli. They were followed up for up to 2 years (mean follow-up 14 months) and compared with a control group without atheromas, matched for age, gender and hypertension. RESULTS Of 42 patients with atheromas, 14 (33%) had 19 vascular events during follow-up (5 brain, 2 eye, 4 kidney, 1 bowel, 7 lower extremity). Of 42 control patients, 3 (7%) had vascular events (2 brain, 1 eye). Univariate analysis identified only protruding atheromas as significantly correlating with events (p = 0.003). There was no positive correlation of events with age, gender, hypertension, smoking, family history, atrial fibrillation, valve replacement, antithrombotic drug use, diabetes or coronary disease. Multivariate analysis showed that only protruding atheromas independently predicted events (p = 0.005, odds ratio 4.3, 95% confidence interval 1.2 to 15.0). Nine patients died in the atheroma group versus six in the control group, but this was not statistically significant (p = 0.39). CONCLUSIONS Protruding atheromas seen on transesophageal echocardiography predict future vascular events.

Aortic Atherosclerotic Disease and Stroke

In the 1940s, most strokes were attributed to cerebral vasospasm, a mechanism that is not given a great deal of credence today. It was not until the early 1950s that Harvard neurologist C. Miller Fisher1 stressed the importance of carotid artery atherosclerosis as a major cause of cerebral infarction. Later that decade, the importance of atrial fibrillation as a cause of cerebral embolism began to be stressed,2 and the presence of a left atrial thrombus was first seen on angiocardiography in 1965.3 Despite the established importance of these 2 causes of stroke, carotid disease and atrial fibrillation, nearly half of strokes were listed as “of undetermined cause” in a large stroke registry as recently as 1989.4 In this series, 40% of 1273 cerebral infarctions in the Stroke Databank of the National Institute of Neurological and Communicative Disorders and Stroke (NINCDS) were thought to be cryptogenic (from the Latin crypticus , meaning secret or mysterious). The clinical syndrome in those patients, as well as the angiographic and computed tomographic (CT) findings, could be reclassified as embolic; however, because no source of embolus could be identified, the authors kept these strokes in the undetermined cause category. In 1990, a third leading cause of embolic stroke was identified on transesophageal echocardiography (TEE), namely severe atherosclerotic plaques in the aortic arch.5 The 3 patients described in that initial report were a 68-year-old woman with dysarthria and an embolus to the foot, a 77-year-old woman with a cerebellar infarction after cardiac catheterization, and a 70-year-old man with staggering, diplopia, and a visual field cut. All 3 had severe plaque in the aortic arch on TEE. In addition, freely mobile projections were seen superimposed on the plaques, making it seem likely that these findings were the reason for the patients’ embolic …

Effect of treatment on the incidence of stroke and other emboli in 519 patients with severe thoracic aortic plaque

Severe aortic plaques seen on transesophageal echocardiography (TEE) are a high-risk cause of stroke and peripheral embolization. Evidence to guide therapy is lacking. Retrospective information was obtained regarding the occurrence of embolic events (stroke, transient ischemic attacks, or peripheral emboli) in 519 patients with severe thoracic aortic plaque seen on TEE since 1988. Treatment with statins, warfarin, or antiplatelet medications was noted. Treatment was not randomized. In a matched-paired analysis, each patient taking each class of therapy was matched for age, gender, previous embolic event, hypertension, diabetes, congestive failure, and atrial fibrillation to someone not taking that medication. Multivariate analysis was also performed. An embolic event occurred in 111 patients (21%). Multivariate analysis showed that statin use was independently protective against recurrent events (p = 0.0001). Matched analysis also showed a protective effect of statins (p = 0.0004; absolute risk reduction 17%, relative risk reduction 59%, number needed to treat [n = 6]). No protective effect was found for warfarin or antiplatelet drugs. The odds ratio for embolic events was 0.3 (95% confidence interval [CI] 0.2 to 0.6) for statin therapy, 0.7 (95% CI 0.4 to 1.2) for warfarin, and 1.4 (95% CI 0.8 to 2.4) for antiplatelet agents. Thus, there is a protective effect of statin therapy, and no significant benefit of warfarin or antiplatelet drugs on the incidence of stroke and other embolic events in patients with severe thoracic aortic plaque on TEE.

Atheromas of the thoracic aorta: clinical and therapeutic update

Atherosclerotic lesions of the thoracic aorta have recently been recognized as an important cause of stroke and peripheral embolization, which may result in severe neurologic damage as well as multiorgan failure and death. Their prevalence is approximately 27% in patients with previous embolic events. Transesophageal echocardiography is the modality of choice for the diagnosis of these atheromas, although computed tomography, magnetic resonance imaging and intraoperative epiaortic ultrasound are complementary. Two clinical syndromes account for the embolic phenomena, atheroemboli and, more commonly, thromboemboli. In addition to such superimposed thrombi, plaque thickness (especially > or =4 mm) also correlates with embolic risk. This risk is high, with 12% of patients having a recurrent stroke within approximately one year, and up to 33% of patients having a stroke or peripheral embolus. In addition, aortic atheromas (as seen with intraoperative transesophageal echocardiography and intraoperative epiaortic ultrasound) are an important cause of stroke during heart surgery requiring cardiopulmonary bypass. Such strokes occur during approximately 12% of cardiac operations employing cardiopulmonary bypass when aortic arch atheromas are seen with transesophageal echocardiography (six times the general intraoperative stroke rate). Although anticoagulant strategies have been reported with encouraging results in nonrandomized studies, prospective, randomized data must be developed before an effective and safe treatment strategy can be determined. This review details the current state of knowledge in this area, including the clinical and pathologic evidence that thoracic aortic atherosclerosis is an important embolic source, data which guide current therapy and future directions for clinical investigation.

Contrast echocardiography clarifies uninterpretable wall motion in intensive care unit patients.

OBJECTIVES The study examined the value of contrast echocardiography in the assessment of left ventricular (LV) wall motion in intensive care unit (ICU) patients. BACKGROUND Echocardiograms done in the ICU are often suboptimal. The most common indication is the evaluation of LV wall motion and ejection fraction (EF). METHODS Transthoracic echocardiograms were done in 70 unselected ICU patients. Wall motion was evaluated on standard echocardiography (SE), harmonic echocardiography (HE), and after intravenous (IV) contrast echocardiography (CE) using a score for each of 16 segments. A confidence score was also given for each segment with each technique (unable to judge; not sure; sure). The EF was estimated visually for each technique, and a confidence score was applied to the EF. RESULTS Uninterpretable wall motion was present in 5.4 segments/patient on SE, 4.4 on HE (p = 0.2), and 1.1 on CE (p < 0.0001). An average of 7.8 segments were read with surety on SE, 9.2 on HE (p = 0.1), and 13.7 on CE (p < 0.0001). Ejection fraction was uninterpretable in 23% on SE, 13% on HE (p = 0.14), and 0% on CE (p = 0.002 vs. HE; p < 0.0001 vs. SE). The EF was read with surety in 56% of patients on SE, 62% on HE (p = 0.47), and 91% on CE (p < 0.0001). Thus, wall motion was seen with more confidence on CE. More importantly, the actual readings of segmental wall motion and EF significantly differed using CE. CONCLUSIONS CE should be used in all ICU patients with suboptimal transthoracic echocardiograms.

Discrete atherosclerotic coronary artery aneurysms : a study of 20 patients

The incidence, angiographic features and natural history of discrete atherosclerotic coronary aneurysms were evaluated in 20 patients with 22 aneurysms (0.2% of 8,422 patients referred for coronary angiography). Fifteen aneurysms (68%) were in the left anterior descending, four (18%) in the circumflex, two (9%) in the right and one (5%) in the left main coronary artery. Aneurysm diameter ranged from 4 to 35 mm (mean 8); 95% of aneurysms were adjacent to a severe obstruction. Seventy-five percent of patients had severe triple vessel disease that included severe left main disease in 15%. Total obstruction of one or two arteries was present in 75%. In patients with wall motion abnormalities, 78% of the abnormalities were in the distribution of the aneurysm. Follow-up (range 1 to 90 months [mean 30]) was obtained in all 20 patients. There were two cardiac and two noncardiac deaths; 12 patients had coronary bypass surgery and of 16 survivors, 13 were angina-free. In conclusion, discrete coronary aneurysms are much less common than diffuse ectasia. Unlike ectasia, they are never found in arteries without severe stenosis, and are most common in the left anterior descending coronary artery. Associated coronary artery disease is more severe in patients with discrete aneurysms than in those with diffuse ectasia. Discrete coronary aneurysms do not appear to rupture, and their resection is not warranted.