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Biomedical subjects

N T Kouchoukos

Publications and source records attributed to N T Kouchoukos.

At least 19 recordsLinked to original sources
PubMed1995

Sensitive detection of abnormal aortic architecture in Marfan syndrome with high-frequency ultrasonic tissue characterization.

BACKGROUND: Aneurysmal dilation of the aorta with subsequent rupture or dissection occurs frequently in patients with Marfan syndrome and is the primary cause of morbidity. These complications are related to the altered composition and disorganized structure of the aortic media. Our goal was to use high-frequency ultrasonic tissue characterization to identify these structural changes in abnormal aorta from patients with Marfan syndrome. We measured integrated backscatter and anisotropy of backscatter of ultrasound from specimens of aorta from patients with Marfan syndrome undergoing aortic root replacement and compared these values with those from aortic specimens of patients without clinical aortic pathology. METHODS AND RESULTS: Aortic tissue was obtained at the time of surgery from 11 patients with Marfan syndrome undergoing repair of an aortic aneurysm or dissection. Normal tissue was obtained at the time of autopsy from 8 patients without evidence of aortic disease. Acoustic microscopy at 50 MHz was performed to measure integrated backscatter from each specimen. The magnitude of ultrasonic anisotropy of backscatter for each tissue type was determined as an index of the three-dimensional (3D) organization of the vessel matrix. The collagen content of each specimen was determined with a hydroxyproline assay. Marfan aortas exhibited less backscatter than did normal aortas (-40.9 +/- 2.9 versus -32.6 +/- 2.2 dB for patients with Marfan syndrome and healthy subjects, respectively, P < .0001). No significant difference in collagen concentrations was observed between normal and Marfan aorta (262.7 +/- 52.7 versus 282.4 +/- 41.8 mg/g tissue for normal and Marfan aortas, respectively, P = .42), despite the large difference in backscatter. Histological analysis revealed striking differences in both the amount and organization of the elastin in the aortic aneurysm segments from patients with Marfan syndrome compared with normal aorta. Normal aorta was characterized by well-formed elastin fibers arranged in a lamellar pattern. The media from aneurysms in Marfan aorta exhibited a profound decrease in elastin content that was associated with loss of the highly aligned and ordered lamellar arrangement. The directional dependence of scattering, or ultrasonic anisotropy, also differed dramatically between the two tissue types. Backscatter from normal aorta decreased substantially when the media was insonified parallel compared with perpendicular to the principal axis of the elastin fibers. Marfan aorta exhibited a much smaller directional dependence of scattering. Normal aortas manifested a 14-fold greater ultrasonic anisotropy than did Marfan aortas (24.1 +/- 3.7 versus 12.4 +/- 3.3 dB for normal and Marfan aortas, P < .0001), which is indicative of the profound extent of matrix disorganization in Marfan syndrome. CONCLUSIONS: These data show that high-frequency ultrasonic tissue characterization sensitively detects changes in vessel wall composition and organization that occur in the aorta of patients with Marfan syndrome. Aortic segments from these patients manifested a significant decrease in integrated backscatter compared with normal aorta (approximately 8 dB, or greater than a 6-fold decrease in scattering). A 15-fold reduction in the ultrasonic anisotropy of Marfan tissue was observed, which suggests a marked disorganization of the 3D architecture of these aortas. These data support the hypothesis that high-frequency ultrasonic tissue characterization may be useful for identifying abnormalities of vessel wall composition, architecture, and material properties.

Adult↗
PubMed1995

Life expectancy in the Marfan syndrome.

Data reported in 1972 indicated that lifespan in patients with the Marfan syndrome is markedly shortened, and that most deaths are cardiovascular. This study was performed to determine whether survival in the Marfan syndrome has changed since 1972, and to discern whether treatment (medical or surgical) has altered prognosis. Survival curves were generated on 417 patients from 4 referral centers, with a definite diagnosis of the Marfan syndrome. Birth date, age at death, cardiovascular surgery, or treatment with beta blockers, or any combination of these, were included in the analysis. Forty-seven of 417 patients died. Mean age at death (41 +/- 18 years) was significantly increased compared with age in 1972 (32 +/- 16 years, p = 0.0023). Median (50%) cumulative probability of survival in 1993 was 72 years compared with 48 years in 1972. Of 112 surgically treated patients, 10-year probability of survival was 70%. Patients undergoing surgery after 1980 enjoyed significantly increased survival than patients who had undergone operation before 1980 (p = 0.008). In conclusion, life expectancy for patients with the Marfan syndrome has increased > 25% since 1972. Reasons for this dramatic increase may include (1) an overall improvement in population life expectancy, (2) benefits arising from cardiovascular surgery, and (3) greater proportion of milder cases due to increased frequency of diagnosis. Medical therapy (including beta blockers) was also associated with an increase in probable survival.

Adult↗
PubMed1995

Transesophageal echocardiography and adult cardiac operations.

Transesophageal echocardiography (TEE) now is used widely as a monitoring technique during and after cardiac operations. Widespread adoption of the technique has provided a wealth of new information. This review analyzes the influence of TEE on the routine conduct of cardiac operations and on surgical decision making in specific areas. Its use in routine hemodynamic monitoring and problem solving, both intraoperatively and postoperatively, is discussed. Transesophageal echocardiography has a particular role in valve operations, in guiding and assessing the immediate results of mitral valve repair. It also has found application in the grading and operative management of the severely atheromatous aorta, the diagnosis and management of aortic dissection, and other aspects of surgery of the thoracic aorta. In addition, management in specialized areas, such as cardiopulmonary transplantation and the insertion and monitoring of ventricular assist devices, have also been helped by the information provided by TEE.

Adult↗
PubMed1995

Coronary artery disease in patients with type A aortic dissection.

The usefulness of preoperative coronary arteriography in patients with type A dissection of the aorta is controversial. To determine the prevalence of arteriosclerotic coronary artery disease in patients with type A dissection of the aorta, we reviewed our experience in 62 patients (42 with acute dissection and 20 with chronic dissection) who underwent operation between January 1, 1986, and December 31, 1993. Among 23 patients with acute dissection who underwent coronary arteriography, 8 (34.8%) had one or more coronary artery lesions causing a greater than 50% narrowing. Among 14 patients with chronic dissection who underwent coronary arteriography, 6 (42.9%) had one or more coronary artery lesions causing a greater than 50% narrowing. There were no fatal complications associated with coronary arteriography. Four patients with acute dissection and 6 patients with chronic dissection underwent coronary artery bypass grafting at the time of operative repair of the aortic dissection, with no operative deaths. On the basis of these findings and the success of combined coronary artery bypass grafting and aortic repair, we recommend that patients with an acute type A dissection who are in stable condition and all patients with a chronic type A dissection of the aorta should undergo preoperative coronary arteriography.

Acute Disease↗
PubMed1995

Profound systemic hypothermia inhibits the release of neurotransmitter amino acids in spinal cord ischemia.

Profound hypothermia induced with cardiopulmonary bypass has a protective effect on spinal cord function during operations on the thoracoabdominal aorta. The mechanism of this protection remains unknown. It has been proposed that the release of excitatory amino acids in the extracellular space plays a causal role in irreversible neuronal damage. We investigated the changes in extracellular neurotransmitter amino acid concentrations with the use of in vivo microdialysis in a swine model of spinal cord ischemia. All animals underwent left thoracotomy and right atrium-femoral artery cardiopulmonary bypass with additional aortic arch perfusion. Lumbar laminectomies were then done and microdialysis probes were inserted stereotactically in the anterior horn of the second and fourth segments of the lumbar spinal cord. The probes were perfused with artificial cerebrospinal fluid at a rate of 2 microliters/min and 15-minute samples were assayed by high-performance liquid chromatography. Group 1 animals (n = 6) underwent aortic clamping distal to the left subclavian artery and proximal to the renal arteries for 60 minutes at normothermia (37 degrees C) and group 2 animals (n = 5) were cooled to a rectal temperature of 20 degrees C before application of aortic clamps, maintained at this level during cardiopulmonary bypass until the aorta was unclamped, and then slowly rewarmed to 37 degrees C. Seven amino acids were studied, including two excitatory neurotransmitters (glutamate and aspartate) and five putative inhibitory neurotransmitters (glycine, gamma-aminobutyric acid, serine, adenosine, and taurine). Glutamate exhibited a threefold increase in extracellular concentration during normothermic ischemia compared with baseline values and remained elevated until 60 minutes after reperfusion. The increase in aspartate concentration was not significant. The extracellular concentrations of glycine and gamma-aminobutyric acid also increased significantly during ischemia and reperfusion. Hypothermia uniformly prevented the release of amino acids in the extracellular space. Glutamate levels remained significantly decreased even after rewarming to normothermia whereas glycine levels returned to baseline values. These results are consistent with a role for excitatory amino acids in the production of ischemic spinal cord injury and suggest that the mechanism of hypothermic protection may be related to decreased release of these amino acids in the ischemic spinal cord.

Analysis of Variance↗
PubMed1995

Hypothermic bypass and circulatory arrest for operations on the descending thoracic and thoracoabdominal aorta.

BACKGROUND: Hypothermic cardiopulmonary bypass with intervals of circulatory arrest is a useful adjunct during operations on the descending thoracic aorta and distal aortic arch when severe aortic disease precludes placement of clamps on the aorta. Hypothermia also has a marked protective effect on spinal cord function during periods of aortic occlusion. METHODS: Fifty-one patients (age range, 22 to 79 years) with descending thoracic or thoracoabdominal aortic disease had resection and graft replacement of the diseased aortic segments using hypothermic cardiopulmonary bypass and intervals of circulatory arrest in situations where the location, extent, or severity of disease precluded placement of clamps on the proximal aorta (8 patients) or (in 43 patients) when extensive thoracic (11) or thoracoabdominal (32) aortic disease was present and the risk for development of spinal cord ischemic injury and renal failure was judged to be increased. Patent intercostal (below T-6) and upper lumbar arteries were attached to the graft whenever possible. RESULTS: Thirty-day mortality was 9.8% (5 patients). Paraplegia occurred in 2 and paraparesis in 1 of the 46 30-day survivors (6.5%). Among the 27 operative survivors with thoracoabdominal aneurysms, paraplegia occurred in 1 of 12 with Crawford type I (8%), 0 of 10 with type II, and 1 of 5 with type III aneurysms (20%). Paraplegia occurred in none of the 12 patients with aortic dissection and in 2 of the 15 patients with degenerative aneurysms. Renal failure requiring dialysis occurred in 1 (2.2%) of the 46 30-day survivors. CONCLUSIONS: Hypothermic circulatory arrest is a valuable adjunct for the treatment of complex aortic disease involving the aortic arch and thoracoabdominal aorta. In patients with thoracoabdominal aneurysms, its use has been associated with a low incidence of renal failure and an incidence of paraplegia/paraparesis in traditionally high-risk subsets (type I and II aneurysms, aortic dissection), which may be less than that observed with other surgical techniques.

Adult↗
PubMed1994

Dextrorphan inhibits the release of excitatory amino acids during spinal cord ischemia.

The release of excitatory amino acids, particularly glutamate, into the extracellular space plays a causal role in irreversible neuronal damage after central nervous system ischemia. Dextrorphan, a noncompetitive N-methyl-D-aspartate receptor antagonist, has been shown to provide significant protection against cerebral damage after focal ischemia. We investigated the changes in extracellular neurotransmitter amino acid concentrations using in vivo microdialysis in a swine model of spinal cord ischemia. After lumbar laminectomies were performed, all animals underwent left thoracotomy and right atrial-femoral cardiopulmonary bypass with additional aortic arch perfusion. Microdialysis probes were then inserted stereotactically into the lumbar spinal cord. The probes were perfused with artificial cerebrospinal fluid and 15-minute samples were assayed using high-performance liquid chromatography. Group 1 animals (n = 9) underwent aortic clamping distal to the left subclavian and proximal to the renal arteries for 60 minutes. Group 2 animals (n = 7) were treated with dextrorphan before application of aortic clamps, and during aortic occlusion and reperfusion. Five amino acids were studied, including two excitatory neurotransmitters (glutamate and aspartate) and three putative inhibitory neurotransmitters (glycine, gamma-amino-butyric acid, and serine). Somatosensory-evoked potentials and motor-evoked potentials were monitored. Glutamate exhibited a threefold increase in extracellular concentration during normothermic ischemia compared with baseline values and remained elevated until 60 minutes after reperfusion. In animals treated with dextrorphan, glutamate concentrations decreased to one-third of baseline levels before aortic clamping and remained unchanged during ischemia and reperfusion. There was early loss of somatosensory-evoked potentials and motor-evoked potentials during ischemia in group 1 animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1994

Managed care involvement by cardiovascular specialists: prevalence, attitudes and influence on practice.

OBJECTIVES: The purpose of this study was to determine the involvement in and attitudes toward managed care by cardiovascular specialists and the influence of such programs on their practices. BACKGROUND: No in-depth study has measured the impact of managed care on cardiovascular specialists. Therefore, we conducted a mail survey to determine the prevalence of managed care arrangements among cardiovascular specialists and variations among pediatric and adult cardiologists and cardiovascular surgeons; the types of managed care arrangements in which cardiovascular specialists are engaged; the reasons why those not participating in managed care have chosen not to do so; and the general attitudes among cardiovascular specialists with regard to various aspects of managed care. In addition, we evaluated the impact of managed care among several aspects of cardiovascular practice. METHODS: A questionnaire was mailed in the spring of 1993 to 4,577 practicing, domestic, American College of Cardiology (ACC) members selected at random from within each primary cardiovascular specialty group (adult cardiologists, pediatric cardiologists and cardiovascular surgeons). Additional data concerning practice characteristics were cross tabulated using results from the 1992 ACC membership profile survey. RESULTS: In total, 1,961 of the 4,577 members responded to the survey, representing a 43% response rate. Of all survey respondents, 76% reported entering into at least one relationship with a health maintenance organization (HMO) or preferred provider organization (PPO). Of those not participating in managed care arrangements, the most frequently mentioned reason was "concern over the quality of care." This reason was cited by 51% of those not entering into HMO relationships and 41% of those not participating in PPOs. The majority of respondents indicated that they do not strongly object to the gatekeeper approach to managing nonemergent patients, although more than half indicated concern that gatekeepers may not be appropriate in the management of cardiac emergencies. In addition, cardiovascular specialists report that under managed care, referrals have not increased, income has decreased, and managed care formularies have not substantially affected their ability to prescribe appropriate medication to their patients. CONCLUSIONS: Despite concerns over the quality of care and contract requirements and general philosophical opposition of cardiovascular specialists, most are becoming integrated into managed care environments.

Adult↗
PubMed1994

Hypothermic circulatory arrest for cerebral protection during combined carotid and cardiac surgery in patients with bilateral carotid artery disease.

OBJECTIVE: The authors evaluated the protective effect of hypothermic circulatory arrest for patients with bilateral carotid artery disease who underwent cardiac surgical procedures. SUMMARY BACKGROUND DATA: Severe bilateral carotid artery disease coexisting with cardiac disease that requires surgical treatment is associated with a substantial incidence of stroke after operations that require cardiopulmonary bypass. The optimal method of management of patients with these coexisting conditions is not established clearly. Because hypothermia has a protective effect on neural and myocardial tissue during cardiac operations, a protocol employing profound hypothermia and a period of circulatory arrest was evaluated in a group of patients who underwent combined carotid and cardiac surgery who were considered to be at increased risk for the development of stroke. METHODS: Fifty patients with bilateral carotid artery disease, including 24 patients with high-grade unilateral stenosis and contralateral occlusion and 6 patients with 80% to 99% bilateral stenosis, underwent combined carotid endarterectomy and cardiac surgery (coronary artery bypass grafting in all 50 patients and additional procedures in 8 patients). Profound systemic hypothermia (15 C) was instituted, and the carotid endarterectomy was performed during a period of circulatory arrest that averaged 30 minutes. The cardiac procedure was performed during the periods of cooling and rewarming. RESULTS: The 30-day mortality rate was 6% (3 patients). There were no early postoperative strokes or reversible ischemic neurologic deficits. There have been seven late deaths in the postoperative period, which extends to 54 months. None of these deaths were caused by stroke. There has been one late stroke, which occurred in the distribution of the unoperated carotid artery. CONCLUSIONS: This technique provides adequate protection of the brain and myocardium during combined carotid and cardiac surgical procedures and appears to reduce the frequency of stroke in the high-risk subgroup of patients with bilateral carotid artery disease.

Aged↗
PubMed1994

Management of the severely atherosclerotic aorta during cardiac operations.

Embolization of atheroma from the ascending aorta is a major cause of stroke following cardiac surgery. We evaluated a protocol for intraoperative detection and treatment of the severely atherosclerotic ascending aorta which included epiaortic ultrasonographic scanning and resection and graft replacement of the involved segment using hypothermic ischemic arrest. During an 81-month interval, 47 patients 50 years of age and older (mean age 71 years) who underwent coronary artery bypass grafting had resection and graft replacement of the ascending aorta. This represented approximately 2% of the patients in this age group who had cardiac operations during this interval. Nineteen patients (40%) required additional procedures. The 30-day mortality rate was 4.3% (2 patients). Both patients died of myocardial failure. None of the 45 surviving patients sustained a perioperative stroke. There have been no strokes or transient ischemic events in the follow-up period, which extends to 72 months (mean 21 months). While this technique for management of the severely atherosclerotic aorta could be considered radical, it was associated with lower mortality and stroke rates than those that were observed in patients with moderate or severe atherosclerosis in whom only minor modifications in technique were made to avoid embolization of atheroma. Resection and graft replacement during a period of hypothermic circulatory arrest is currently our preferred method of treatment for the severely atherosclerotic aorta during cardiac surgery.

Aged↗
PubMed1994

Atherosclerosis of the ascending aorta. Prevalence and role as an independent predictor of cerebrovascular events in cardiac patients.

BACKGROUND AND PURPOSE: The cause of cerebral and peripheral embolism remains undetermined in a significant number of patients. An atherosclerotic thoracic aorta has thus far been considered to be an uncommon one. METHODS: To define the potential role of the ascending thoracic aorta as an embolic source, intraoperative ultrasonic aortic imaging was performed in 1200 of 1334 consecutive patients aged 50 years and older who were undergoing cardiac surgery. Patients were divided into two groups according to the results of the ultrasound study in terms of presence or absence of atherosclerotic disease. The prevalence of previous neurological events in the two groups was characterized and compared. RESULTS: Ascending aortic atherosclerosis was present in 231 (19.3%) of the patients studied. Patients in this category were older (P < .0001). A higher percentage of them were smokers (P < .0001) compared with patients with less severe disease. Coronary artery disease was more extensive (P = .012), and a higher percentage of these patients had a history of peripheral vascular disease (P < .0001). Univariate analysis of the subjects with (n = 158) and without (n = 1042) previous neurological events indicated that age, body mass index, atrial fibrillation, hypertension, and atherosclerosis of the ascending aorta were associated significantly with previous occurrence of a cerebrovascular accident. For the group as a whole, multiple logistic regression analysis demonstrated that hypertension (odds ratio, 1.81; P = .002), atherosclerosis of the ascending aorta (odds ratio, 1.65; P = .013), and atrial fibrillation (odds ratio, 1.54; P = .060) were significantly and independently associated with the occurrence of previous neurological events. CONCLUSIONS: Atherosclerosis of the ascending aorta is an independent risk factor for cerebrovascular events. An atherosclerotic ascending aorta may represent a potential source of emboli or may be a marker of generalized atherosclerosis.

Age Factors↗
PubMed1993

Renal dysfunction and intravascular coagulation with aprotinin and hypothermic circulatory arrest.

High-dose aprotinin was used in 20 patients undergoing primary or repeat operations on the thoracic or thoracoabdominal aorta using cardiopulmonary bypass and hypothermic circulatory arrest. The activated clotting times immediately before the establishment of hypothermic circulatory arrest exceeded 700 seconds in all but 1 patient. Three patients (15%) required reoperation for bleeding. Seven patients died during hospitalization, and 5 had postmortem examination. Platelet-fibrin thrombi were present in multiple organs including the coronary arteries of 4 patients with myocardial infarction or failure, the pulmonary arteries of 2 patients, 1 of whom died of acute right ventricular failure, the brains of 2 patients who sustained a stroke, and the kidneys of 4 patients, 3 of whom had development of renal dysfunction. Renal dysfunction occurred in 13 patients (65%), and all were 65 years of age or older. Five of these patients required hemodialysis. Among 20 age-matched patients who had similar operations without aprotinin, there was one hospital death (5%) from myocardial infarction, and renal dysfunction developed in 1 patient (5%), who did not require dialysis. None of these 20 patients required reoperation for bleeding. Although aprotinin has been shown to reduce blood loss in patients having cardiac operations employing cardiopulmonary bypass, this benefit was not attained in this group of patients with thoracic aortic disease in whom hypothermic circulatory arrest was used. Use of aprotinin in elderly patients undergoing these procedures was associated with an increased risk of renal dysfunction and failure, and of myocardial infarction and death.

Aged↗
PubMed1992

Intraaortic balloon counterpulsation: patterns of usage and outcome in cardiac surgery patients.

Between January 1, 1986, and May 6, 1991, 7,884 cardiac surgical procedures requiring cardiopulmonary bypass were performed at our institution, including 672 (9.8% of adult procedures) performed in 669 patients that were associated with preoperative (n = 240), intraoperative (n = 353), or postoperative (n = 79) use of an intraaortic balloon pump. The mean age of recipients was 65.3 years (range, 16 to 89 years). Intraaortic balloon pump usage increased during the study period from 6.4% of patients (83/1,298) in 1986 to 12.7% of patients (169/1,333) in 1990. The relative distribution between preoperative (mean, 35.7%), intraoperative (52.5%), and postoperative (11.8%) insertion remained nearly constant during the study period. The overall operative (30-day) mortality for patients with preoperative, intraoperative, or postoperative insertion of the intraaortic balloon pump was 19.6%, 32.3%, and 40.5%, respectively (X2 = 16.4; p less than 0.001). Although use of the intraaortic balloon pump in the intraoperative and postoperative settings is accompanied by a favorable outcome in most patients, the high associated mortality suggests the need for earlier use of the intraaortic balloon pump or other supportive measures such as the ventricular assist device.

Angina, Unstable↗
PubMed1992

Transesophageal echocardiography predicts successful withdrawal of ventricular assist devices.

Transesophageal echocardiography has been found to be an effective technique for the real-time assessment of myocardial and valvular function in postoperative patients. To determine the value of transesophageal echocardiography in patients with mechanical assist devices, we performed daily, bedside transesophageal echocardiography on 16 patients with right (n = 3), left (n = 1), or biventricular assist devices (n = 12). We obtained four-chamber and short-axis views in all patients. Valvular function and the presence of left-to-right shunts were evaluated by means of color flow Doppler imaging. During the echocardiographic study ventricular assist device flow was diminished to less than 1.5 L/min, and inotropic agents (dobutamine or epinephrine) were given to assess ventricular reserve. Changes in day-to-day ventricular function were assessed in comparisons made by two observers (one unaware of the study sequence) using a semiquantitative method for wall motion analysis. The left ventricular wall motion scores in the patients successfully weaned from left or biventricular assist devices (n = 5) improved (14.2 +/- 1.6 versus 8.2 +/- 1.5, p < 0.0001). The scores did not improve in patients who remained dependent on the devices (n = 8). Two patients with only right ventricular assist devices were successfully weaned after documentation of improvement of right ventricular function by transesophageal echocardiography. Transesophageal echocardiography documented a clot compressing the heart in three patients; intracavitary thrombi were seen in two other patients. Marked hemodynamic improvement occurred after surgical decompression. In conclusion, transesophageal echocardiography is a safe, effective method for the assessment of ventricular function of patients on ventricular assist device support. In addition, it allows one to assess valvular function and the presence or absence of impaired ventricular filling.

Adult↗
PubMed1992

Management of the severely atherosclerotic ascending aorta during cardiac operations. A strategy for detection and treatment.

Embolization of atheroma from the ascending aorta is a principal cause of stroke after cardiac operations. We have previously shown that intraoperative ultrasonographic scanning of the aorta rapidly, safely, and accurately identifies atheromatous disease in the ascending aorta. Intraoperative ultrasonography of the ascending aorta was performed in 500 of a consecutive series of 540 patients 50 years of age or older (mean 68 years) who underwent a variety of cardiac operations. Eighty-nine percent required bypass grafting. Sixty-eight patients (13.6% of the total) with a mean age of 72 years (range 55 to 85 years) had significant atheromatous disease in the ascending aorta and were considered to be at increased risk for embolization. Palpation identified the atheromatous disease in only 26 (38%) of these patients and underestimated its severity. A total of 168 modifications in the standard techniques for cannulation and clamping of the aorta were implemented in the 68 patients (mean 2.5 per patient) and included alterations in the sites of aortic cannulation (50 patients), aortic clamping (54 patients), attachment of the vein grafts (35 patients), and cannulation for infusion of cardioplegic solution (29 patients). Ten patients with severe diffuse atheromatous disease underwent graft replacement of the ascending aorta with hypothermic circulatory arrest without aortic clamping. Fourteen patients with symptoms or with high-grade carotid artery occlusive disease were treated by concomitant carotid endarterectomy. Thirty-day mortality for the entire group was 3.4% (17 patients). Permanent neurologic deficits occurred in five (1.0%) of the patients in the entire group but in none of the 68 patients with significant atheromatous disease in whom modifications in technique were used. One patient in the latter group had a reversible ischemic neurologic deficit. Modification of standard cannulation and clamping techniques based on ultrasonography may reduce the frequency of stroke related to atheromatous embolization.

Aged↗