In vivo evaluation of a breast-specific magnetic resonance guided focused ultrasound system in a goat udder model.

PURPOSE: This work further evaluates the functionality, efficacy, and safety of a new breast-specific magnetic resonance guided high intensity focused ultrasound (MRgFUS) system in an in vivo goat udder model. METHODS: Eight female goats underwent an MRgFUS ablation procedure using the breast-specific MRgFUS system. Tissue classification was achieved through the 3D magnetic resonance imaging (MRI) acquisition of several contrasts (T1w, T2w, PDw, 3-point Dixon). The MRgFUS treatment was performed with a grid trajectory executed in one or two planes within the glandular tissue of the goat udder. Temperature was monitored using a 3D proton resonance frequency (PRF) MRI technique. Delayed contrast enhanced-MR images were acquired immediately and 14 days post MRgFUS treatment. A localized tissue excision was performed in one animal and histological analysis was performed. Animals were available for adoption at the conclusion of the study. RESULTS: The breast-specific MRgFUS system was able to ablate regions ranging in size from 0.4 to 3.6 cm(3) in the goat udder model. Tissue damage was confirmed through the correlation of thermal dose measurements obtained with realtime 3D MR thermometry to delayed contrast enhanced-MR images immediately after the treatment and 14 days postablation. In general, lesions were longer in the ultrasound propagation direction, which is consistent with the dimensions of the ultrasound focal spot. Thermal dose volumes had better agreement with nonenhancing areas of the DCE-MRI images obtained 14 days after the MRgFUS treatment. CONCLUSIONS: The system was able to successfully ablate lesions up to 3.6 cm(3). The thermal dose volume was found to correlate better with the 14-day postablation nonenhancing delayed contrast enhanced-MR image volumes. While the goat udder is not an ideal model for the human breast, this study has proven the feasibility of using this system on a wide variety of udder shapes and sizes, demonstrating the flexibility that would be required in order to treat human subjects.

Design and characterization of a laterally mounted phased-array transducer breast-specific MRgHIFU device with integrated 11-channel receiver array.

PURPOSE: This work presents the design and preliminary evaluation of a new laterally mounted phased-array MRI-guided high-intensity focused ultrasound (MRgHIFU) system with an integrated 11-channel phased-array radio frequency (RF) coil intended for breast cancer treatment. The design goals for the system included the ability to treat the majority of tumor locations, to increase the MR image's signal-to-noise ratio (SNR) throughout the treatment volume and to provide adequate comfort for the patient. METHODS: In order to treat the majority of the breast volume, the device was designed such that the treated breast is suspended in a 17-cm diameter treatment cylinder. A laterally shooting 1-MHz, 256-element phased-array ultrasound transducer with flexible positioning is mounted outside the treatment cylinder. This configuration achieves a reduced water volume to minimize RF coil loading effects, to position the coils closer to the breast for increased signal sensitivity, and to reduce the MR image noise associated with using water as the coupling fluid. This design uses an 11-channel phased-array RF coil that is placed on the outer surface of the cylinder surrounding the breast. Mechanical positioning of the transducer and electronic steering of the focal spot enable placement of the ultrasound focus at arbitrary locations throughout the suspended breast. The treatment platform allows the patient to lie prone in a face-down position. The system was tested for comfort with 18 normal volunteers and SNR capabilities in one normal volunteer and for heating accuracy and stability in homogeneous phantom and inhomogeneous ex vivo porcine tissue. RESULTS: There was a 61% increase in mean relative SNR achieved in a homogeneous phantom using the 11-channel RF coil when compared to using only a single-loop coil around the chest wall. The repeatability of the system's energy delivery in a single location was excellent, with less than 3% variability between repeated temperature measurements at the same location. The execution of a continuously sonicated, predefined 48-point, 8-min trajectory path resulted in an ablation volume of 8.17 cm(3), with one standard deviation of 0.35 cm(3) between inhomogeneous ex vivo tissue samples. Comfort testing resulted in negligible side effects for all volunteers. CONCLUSIONS: The initial results suggest that this new device will potentially be suitable for MRgHIFU treatment in a wide range of breast sizes and tumor locations.

Comparison of surgical outcomes between teaching and nonteaching hospitals in the Department of Veterans Affairs.

OBJECTIVE: To determine whether the investment in postgraduate education and training places patients at risk for worse outcomes and higher costs than if medical and surgical care was delivered in nonteaching settings. SUMMARY BACKGROUND DATA: The Veterans Health Administration (VA) plays a major role in the training of medical students, residents, and fellows. METHODS: The database of the VA National Surgical Quality Improvement Program was analyzed for all major noncardiac operations performed during fiscal years 1997, 1998, and 1999. Teaching status of a hospital was determined on the basis of a background and structure questionnaire that was independently verified by a research fellow. Stepwise logistic regression was used to construct separate models predictive of 30-day mortality and morbidity for each of seven surgical specialties and eight operations. Based on these models, a severity index for each patient was calculated. Hierarchical logistic regression models were then created to examine the relationship between teaching versus nonteaching hospitals and 30-day postoperative mortality and morbidity, after adjusting for patient severity. RESULTS: Teaching hospitals performed 81% of the total surgical workload and 90% of the major surgery workload. In most specialties in teaching hospitals, the residents were the primary surgeons in more than 90% of the operations. Compared with nonteaching hospitals, the patient populations in teaching hospitals had a higher prevalence of risk factors, underwent more complex operations, and had longer operation times. Risk-adjusted mortality rates were not different between the teaching and nonteaching hospitals in the specialties and operations studied. The unadjusted complication rate was higher in teaching hospitals in six of seven specialties and four of eight operations. Risk adjustment did not eliminate completely these differences, probably reflecting the relatively poor predictive validity of some of the risk adjustment models for morbidity. Length of stay after major operations was not consistently different between teaching and nonteaching hospitals. CONCLUSION: Compared with nonteaching hospitals, teaching hospitals in the VA perform the majority of complex and high-risk major procedures, with comparable risk-adjusted 30-day mortality rates. Risk-adjusted 30-day morbidity rates in teaching hospitals are higher in some specialties and operations than in nonteaching hospitals. Although this may reflect the weak predictive validity of some of the risk adjustment models for morbidity, it may also represent suboptimal processes and structures of care that are unique to teaching hospitals. Despite good quality of care in teaching hospitals, as evidenced by the 30-day mortality data, efforts should be made to examine further the structures and processes of surgical care prevailing in these hospitals.

Effect of a resident self-study and presentation program on performance on the thoracic surgery in-training examination.

BACKGROUND: In this study we examine whether conversion from a didactic lecture format to a resident self-study and presentation program can improve performance on the Thoracic Surgery In-Training Examination (TSITE). METHODS: During the first 5 years, educational conferences were didactic lectures delivered by the attending thoracic surgery staff (group 1, n = 9 residents). During the second 5 years, residents prepared and delivered reviews from major textbook sources (group 2, n = 9 residents). Scores on the American Board of Surgery In-Training Examination (ABSITE) as a chief resident in general surgery were analyzed using one-way analysis of variance to assess fund of knowledge and test-taking skills prior to thoracic surgery training for the two groups. Scores on the TSITE during the first and second years of thoracic surgery training were recorded for each resident and analyzed using a paired t test. The data are expressed as the mean +/- standard deviation. RESULTS: Eighteen thoracic surgery residents over a 10-year period were involved in the study. ABSITE scores as a chief resident in general surgery did not differ between the two groups. Residents in group 1 improved their percentile rank from the first to the second year by a mean of 11%+/-12%, whereas those in group 2 improved their scores by a mean of 31%+/-21% (P < 0.05). CONCLUSIONS: When compared with a didactic lecture format, a resident self study and presentation program improves performance on the Thoracic Surgery In-Training Examination. This improvement in performance typically manifests during the second year of thoracic surgery training.

Coronary artery bypass grafting with cardiopulmonary bypass versus off-pump cardiopulmonary bypass grafting: does eliminating the pump reduce morbidity and cost?

BACKGROUND: Cardiopulmonary bypass (CPB) may contribute to the complications and cost of coronary artery bypass grafting (CABG). Off-pump CABG (OPCAB) allows coronary revascularization without CPB. We hypothesized that OPCAB provides satisfactory graft patency while reducing complications and cost compared with CABG with CPB. METHODS: We prospectively followed 80 patients undergoing CABG: 40 patients undergoing OPCAB and 40 patients undergoing CABG with CPB. OPCAB patients underwent angiography within 48 hours of surgery to determine early graft patency. Incidence of complications, length of stay, and costs were recorded for each patient. The influence of the number of vessels bypassed was analyzed. RESULTS: OPCAB patients (n = 40) underwent grafting of 2.7 +/- 0.7 vessels per patient compared with 3.6 +/- 0.8 vessels per patient in the CABG with CPB group (n = 40) (p < 0.0001). Angiography demonstrated 105 of 108 (97%) of grafts were patent in the OPCAB group. Incidence of complications, length of stay, and costs did not differ between the OPCAB and CABG with CPB groups. Number of vessels grafted showed a positive correlation to total costs in both groups. CONCLUSIONS: While OPCAB provided satisfactory early graft patency, there was no significant difference between OPCAB and CABG with CPB with regard to cost, length of stay, or incidence of complications. In this study, eliminating CPB did not reduce morbidity or cost after CABG.

Early and sufficient feeding reduces length of stay and charges in surgical patients.

BACKGROUND: The role of perioperative nutrition in surgical patients remains controversial. We performed a Clinical Practice Improvement (CPI) study that, while controlling for severity of illness, explored the relationship between the timing and amount of parenteral or enteral nutrition, with two outcomes: length of stay (LOS) and total charges in patients undergoing open intestinal operations. MATERIALS AND METHODS: A CPI study was conducted at eight hospitals to determine which process steps were associated with shorter LOS and lower charges. Hospital charts were abstracted for over 800 components of detailed patient, process, and outcome measures. Severity of illness was measured multiple times during the stay using the Comprehensive Severity Index, a disease-specific physiologic severity measurement instrument. Data on 1007 patients undergoing intestinal operations, 183 of whom received nutritional support, were then analyzed using multiple regression procedures. Early (within 48 h of surgery) and sufficient (60% of protein and calorie goals) nutrition, patient variables, and a severity of illness measure were included as independent variables and LOS and hospital charges were used as dependent variables. RESULTS: Mean patient age was 58 years. After controlling for severity of illness, patients who received early and sufficient nutrition had significantly shorter LOS (11.9 days) and lower charges ($34,602) than patients who received early (13.3; $36,452), sufficient (14.6, $39,883), or neither early nor sufficient (14.8, $38,578) (P < or = 0.0001 for early and sufficient versus all other groups). CONCLUSIONS: CPI methodology provides a detailed view of the actual relationship between the timing and the amount of nutrition with LOS and hospital charge outcomes.

Performance standards: piece of cake or pie in the sky?

BACKGROUND: Centrally mandated levels of performance are now common in the Veterans Health Administration. Performance standards for ambulatory procedures were developed based on HCFA data. The 11 procedures to be measured were arthroscopy, breast biopsy, eyelid procedures, lens/cataracts, bronchoscopy, endoscopy, colonoscopy, hernia repair, cystoscopy, laparoscopy, and cardiac catheterization. Were the performance standards for ambulatory procedures reasonable and achievable in a tertiary care VA? METHODS: Ambulatory procedure performance standards for the 11 selected procedures were evaluated for Fiscal Year 1998 at one tertiary care VA and at each of the 22 Veteran's Integrated Service Networks (VISNs). Further review was undertaken for those procedures in which performance was below the fully successful level. This included chart reviews at the tertiary care VA and analysis of caseloads by VISN. Descriptive statistics were used as well as Student's t test to analyze the difference in means. RESULTS: The tertiary care VA performed at the fully successful level for 6 procedures and at the exceptional level for 3 procedures. Performance levels for bronchoscopy and laparoscopy were below the preset goals. At the VISN level, 8 VISNs performed at the fully successful/exceptional level for all 11 procedures. The remaining 14 were deficient in 1 to 4 procedures. Eight of the VISNs were deficient in 2 or 3 procedures. Six VISNs were deficient in laparoscopy. CONCLUSIONS: The majority of centrally mandated performance standards appear to be reasonable and achievable. One notable exception is laparoscopy. Surgeons should understand how performance standards are calculated at their institution and review the data carefully for any systematic errors. Underperformance can be used as an opportunity to improve both data collection and outcomes.

Using the Veterans Administration National Surgical Quality Improvement Program to improve patient outcomes.

BACKGROUND: The primary goal of collecting quality assurance data is to ultimately improve patient care. The VA National Surgical Quality Improvement Program (NSQIP) provides each station with risk-adjusted morbidity and mortality data on a regular basis. This report of one medical center's use of the risk-adjusted data shows how it can be used to improve patient care. MATERIALS AND METHODS: Risk-adjusted surgical outcome data for Fiscal Year 1996 (FY96) was received from the NSQIP coordinating center. The Salt Lake City VA medical center was identified as a high outlier for morbidity in general surgery. Patient charts were reviewed and data analyzed to determine practice patterns and to determine if there were any provider issues. Data analysis revealed a large number of wound complications and uncovered a practice pattern of closure of contaminated wounds. Using these data and data from the literature, wound infection and disruption prevention protocols were instituted in the fall of 1997. Wound complications from January to December 1996 (preprotocol) and January to December 1998 (postprotocol) were compared using Student's t test. RESULTS: The total number of operations in 1998 was 719 compared with 634 in 1996. Superficial wound infections dropped from 3.6 to 1.7%, while overall wound complications dropped from 5.5 to 2.9%. None of these changes were statistically significant. CONCLUSIONS: Although introduction of wound infection and disruption prevention protocols did not result in a statistically significant decrease in wound complication, it did result in a clinically significant improvement in patient care.

Aprotinin preserves myocardial biochemical function during cold storage through suppression of tumor necrosis factor.

OBJECTIVE: Inflammatory cytokines, particularly tumor necrosis factor, contribute to myocardial dysfunction after ischemia-reperfusion injury. Aprotinin may improve outcomes in cardiac surgery through suppression of inflammatory mediators. We hypothesized that aprotinin may exert its beneficial effects through suppression of tumor necrosis factor alpha. METHODS: Adult rat hearts were precision cut into slices with a thickness of 200 microm and stored in crystalloid cardioplegic solution alone or with one of the following additions: aprotinin or tumor necrosis factor alpha, aprotinin plus tumor necrosis factor alpha, a monoclonal antibody to tumor necrosis factor alpha, or a polyclonal antibody to the tumor necrosis factor alpha receptor. Myocardial biochemical function was assessed by adenosine triphosphate content and capacity for protein synthesis immediately after slicing (0 hours) and after 2, 4, and 6 hours of storage at 4 degrees C. The content of tumor necrosis factor alpha was measured by an enzyme-linked immunosorbent assay. Six slices were assayed at each time point for each solution. The data were analyzed by analysis of variance and are expressed as the mean +/- standard deviation. RESULTS: When stored in cardioplegic solution containing aprotinin, the heart slices demonstrated (1) an increase in adenosine triphosphate content and protein synthesis (P <.0001), (2) a decrease in intramyocardial generation of tumor necrosis factor alpha (P

A new model for recognizing and rewarding the educational accomplishments of surgery faculty.

Faculty members' educational endeavors have generally not received adequate recognition. The Association for Surgical Education in 1993 established a task force to determine the magnitude of this problem and to create a model to address the challenges and opportunities identified. To obtain baseline information, the task force reviewed information from national sources and the literature on recognizing and rewarding faculty members for educational accomplishments. The group also developed and mailed to surgery departments at all U.S. and Canadian medical schools a questionnaire asking about the educational endeavors of the surgery faculty and their recognition for such activities. The response rate after two mailings was only 56%, but the responses reaffirmed the inadequacy of systems for rewarding and recognizing surgeon-teachers and surgeon-educators, and confirmed that the distinction between the roles of teacher and educator was rarely made. The task force created a four-tier hierarchical model based on the designations teacher, master teacher, educator, and master educator as a framework to offer appropriate recognition and rewards to the faculty, and endorsed a broad definition of educational scholarship. Criteria for various levels of achievement, ways to demonstrate and document educational contributions, appropriate support and recognition, and suggested faculty ranks were defined for these levels. The task force recommended that each surgery department have within its faculty ranks a cadre of trained teachers, a few master teachers, and at least one educator. Departments with a major commitment to education should consider supporting a master educator to serve as a resource not only for the department but also for the department's medical school and other medical schools. Although this model was created for surgery departments, it is generalizable to other disciplines.

Characteristics of women surgeons in the United States.

BACKGROUND: Women surgeons are becoming increasingly prevalent. Despite this, there have been few studies of personal or professional characteristics of US surgeons of either gender. METHODS: Data were taken from the Women Physicians' Health Study, a nationally representative random sample (n = 4,501 respondents) of US women physicians, and data were analyzed in SUDAAN. RESULTS: Surgeons were younger, and more likely to be US born, white, unmarried, and childless than were other women physicians; their personal health behaviors were similar to those of others. They worked significantly more clinical hours and call nights, but were not more likely to report feeling that they worked too much, had too much work stress, or had less control of their work environment. Their career satisfaction was similar to that of other women physicians, and satisfaction with their specialty was greater. They were less avid preventionists than were primary care practitioners, and somewhat less avid than other specialists. CONCLUSIONS: Women surgeons differ in interesting and important ways from other women physicians.

Does volume of patients seen in an outpatient setting impact test scores?

BACKGROUND: Methods of teaching surgery in the outpatient setting and means to measure the effectiveness of these methods have not been defined. This study was designed to evaluate the impact of number of outpatient encounters on test scores for third-year medical students. METHODS: Students rotating on the required third-year surgery clerkship between July 1994 and June 1996 kept a log of their activities including number of patients seen in clinic, number of cases scrubbed, and pages read. At the end of the rotation the students were given an essay examination and a multiple-choice examination. The data were analyzed looking for correlation between examination scores and volume of patients seen. United States Medical Licensing Examination (USMLE) Step 1 scores were used as a baseline measure to compare the rotation groups. RESULTS: USMLE scores did not differ between groups. Mean essay examination scores varied significantly between some rotation groups, but did not follow a pattern. There was no correlation between the number of patients seen in clinic and essay examination scores. There was a significant correlation between essay score and USMLE Step 1 score (Pearson's r = 0.398) and between essay and multiple-choice examination scores (Pearson's r = 0.313). There was a significant negative correlation between number of patients seen in clinic and number of cases scrubbed (Pearson's r = -0.347). CONCLUSIONS: Participation in outpatient surgery clinics did not result in improved performance on written examinations in this surgery clerkship. To achieve the most benefit from the outpatient clinic, objectives of the experience need to be determined and appropriate tools used to measure their successful achievement.

Who should teach medical students surgery?

BACKGROUND: Medical schools are undergoing major curricular reform, partly in attempts to increase the number of graduates pursuing careers in the generalist disciplines. These reforms have often resulted in a shortening of the surgery clerkship, decreasing students' experiences in several domains important to the generalist. METHODS: A seven-question survey of clerkship directors of US medical schools was administered to measure the magnitude of curriculum change during the past 5 years affecting the surgery and family practice clerkships. The survey also addressed attitudes about the purpose of the surgery clerkship. RESULTS: There was an 80% (103 of 129) response rate. Between 1989 and 1994, surgery clerkships decreased on average from 11 to 10.2 weeks (P <0.05) while family practice clerkships increased from 4.2 to 6.8 weeks (P <0.05). Ninety-one percent of clerkship directors felt the primary goal of the clerkship should be to train generalists. CONCLUSIONS: The length of the surgery clerkship has decreased at several institutions. In order to ensure an appropriate educational experience for medical students, surgeons must participate actively in curriculum reform within medical schools and highlight their unique role in training generalists.

Long-term results of cardiac transplantation in patients older than sixty years. UTAH Cardiac Transplant Program.

Advanced age has traditionally been a contraindication to cardiac transplantation. We have, however, offered cardiac transplantation to patients older than 60 years with end-stage heart failure if they were otherwise acceptable candidates. From 1985 to 1994, 527 patients underwent cardiac transplantation. Among these patients, 101 were older than 60 years at transplantation. The mean follow-up of this group is 6 years. Patients older than 60 years had significantly fewer rejection episodes per patient than those who were younger than 60 years at transplantation (1.9 +/- 1.3 vs 2.6 +/- 1.8, p = 0.009). No difference in the number of infectious complications per patient was detected between the two groups. Both short-term and long-term survival after transplantation were significantly lower for patients who were older than 60 years at transplantation than for younger patients (p < 0.05). The 6-year actuarial survival after transplantation for patients older than 60 years was 54% compared with 72% for patients younger than 60 years at transplantation (p < 0.05). Patients older than 60 years at transplantation were more likely to die of infectious complications or malignant disease after transplantation (p < 0.05). We believe caution is warranted in offering cardiac transplantation to patients older than 60 years. This group of patients should be carefully observed for the development of potentially life-threatening infectious complications or new malignant tumors after transplantation.

The effects of improved hemodynamics on aortic dimensions in patients undergoing heart transplantation.

PURPOSE: Retrospective studies have demonstrated an accelerated growth rate of abdominal aortic aneurysms in heart transplant patients. This prospective study was undertaken to define the relationship between cardiac hemodynamics and posttransplant aortic dilation. METHODS: Sixty-eight patients undergoing heart (n = 60) or heart-lung (n = 8) transplantation were prospectively evaluated with abdominal ultrasonography before transplantation and annually after transplantation. Risk factors implicated in aneurysm growth, including age, indication for transplantation, immunosuppression, posttransplantation hypertension, and abdominal aortic dimension before transplantation were recorded. All patients underwent annual coronary artery catheterization and multiple gated acquisition scanning. RESULTS: Thirty-seven patients (54%) had no change in aortic diameter after transplantation (pretransplantation and posttransplantation diameter = 1.8 +/- 0.3 cm), over a mean follow-up period of 28 +/- 14 months. In the remaining 31 (46%) patients, aortic diameter increased by 0.5 +/- 0.6 cm over 31 +/- 15 months (p < 0.05). Four (6%) of these 31 patients had abdominal aortic aneurysms (mean aortic diameter = 5.0 +/- 0.8 cm). The mean increase in aortic diameter among these 4 patients was 1.8 +/- 0.2 cm (annual rate of growth = 0.96 +/- 0.3 cm/year). Patients experiencing an increase in aortic dimension after transplantation had significantly lower (p < 0.005) pretransplantation ejection fractions (17.1% +/- 10.5% vs 28.6% +/- 18.1%) and, as a consequence, significantly greater (p < 0.05) increases in their ejection fractions after transplantation compared with patients with stable aortic dimensions (42.7% +/- 12.6% vs 31.8% +/- 18.0%). CONCLUSIONS: Of 68 heart transplant patients prospectively evaluated, aortic diameter increased in 31 (46%); new aneurysms developed in four of these patients. Greater incremental increases in cardiac ejection fraction were significant correlates with aortic enlargement.

Female surgeons in the 1990s. Academic role models.

As part of a larger survey of the membership of the Association of Women Surgeons, data were collected to characterize the participation of women in academic surgery and surgical education. Of the 1500 members, 676 (45%) responded, and 318 of these respondents held a faculty appointment. Two hundred thirty-nine of the respondents' practices were based in a university or university-affiliated hospital. This sample was biased toward more academically motivated, upwardly mobile surgeons. Two hundred thirty-six of the respondents believed policies relating to tenure are unfair to women. Four hundred fifty-three respondents reported having role models at some point in their career, half of whom were men. However, only 204 still had access to role models or mentors at the time of the survey. Six hundred thirty respondents believed that female medical students need successful female surgeons as role models.

Cytomegalovirus appendicitis in a patient with human immunodeficiency virus infection. Case report and review of the literature.

We report a case of chronic abdominal pain with subsequent development of acute right lower quadrant tenderness in a patient infected with the human immunodeficiency virus. Ultrasonography and computed tomography revealed an enlarged appendix. On subsequent laparotomy, the patient was found to have appendicitis due to cytomegalovirus. Six additional cases of this infection were identified in a review of the literature. The course of cytomegalovirus appendicitis in these patients was prolonged and atypical compared with noncompromised patients with acute appendicitis. Because perforation may occur, surgery is advocated when this diagnosis is suspected in the patient infected with human immunodeficiency virus.

Risk factors for stroke in patients undergoing coronary artery bypass grafting.

Stroke is a significant cause of morbidity and mortality following coronary artery bypass grafting (CABG). Over a 30-month period, 245 consecutive patients undergoing elective CABG were prospectively examined to determine which risk factors might predispose to stroke following surgery. The risk factors evaluated included hypertension, diabetes, hypercholesterolemia, hypertriglyceridemia, smoking, atrial fibrillation, a history of cerebrovascular accident or transient ischemic attack, carotid artery stenosis > 60% documented by duplex scanning, severe atherosclerosis of the ascending aorta, and the presence of ventricular thrombus. Postoperative stroke occurred in five of the 245 patients (2%), four evident immediately on awakening and one on day 7 after surgery. The probable causes of the immediate strokes were atheroembolism in three patients and severe ipsilateral carotid stenosis in one. Hypertensive hemorrhage was responsible for the one case of delayed stroke. In this study, carotid artery stenosis did not presage stroke following CABG, but ventricular thrombus was highly predictive of stroke after surgery.