High prevalence of the PER-1 gene among carbapenem-resistant Acinetobacter baumannii in Riyadh, Saudi Arabia.

The prevalence of carbapenem-resistant Acinetobacter baumannii in Saudi Arabia and their resistance genetic mechanisms are yet to be identified. We studied the prevalence and genetic diversity of extended-spectrum beta-lactamase genes, particularly the PER-1 gene, among carbapenem-resistant A. baumannii strains from patients at a tertiary care hospital in Riyadh, Saudi Arabia between 2006 and 2014. Fresh subcultured samples were tested for antimicrobial susceptibility minimum inhibitory concentration (MIC). Total genomic DNA was extracted from each isolate and further used for polymerase chain reaction (PCR) genotyping, sequence-based typing (SBT) of PER-1 and OXA-51-like gene, and multilocus sequence typing (MLST) of positive isolates. Randomly selected clinical isolates (n = 100) were subjected to MLST. A total of 503 isolates were characterized as multidrug-resistant (MDR) using the MIC. Isolates were further PCR tested for bla -TEM and bla -PER-1 resistance genes (n = 503). The genotyping results showed that 68/503 (14 %) isolates were positive to bla TEM. The genotyping results of PER-1-like genes showed that 384/503 (76.3 %) were positive among MDR Acinetobacter isolates. Based on SBT, the majority of these isolates were clustered into three main groups including isolates harboring PER-1: AB11 (bla -PER-1), isolate AB16 (bla -PER-1), and, finally, the plasmid pAB154 (bla -PER-7). Remarkably, many isolates were concealing the PER-1 gene and harboring the TEM resistance genes as well. MLST results for selected isolates (n = 100) identified four main sequence types (STs: 2, 19, 20, and 25) and four novel isolates (ST 486-489). We report 76.3 % prevalence of the PER-1 resistance gene among Acinetobacter clinical isolates from Riyadh, Saudi Arabia. Further work is needed to explore the clinical risks and patient outcome with such resistance related to healthcare-associated infections and investigate the genetic and molecular mechanisms that confer the MDR phenotype.

Genetic diversity of OXA-51-like genes among multidrug-resistant Acinetobacter baumannii in Riyadh, Saudi Arabia.

We explore the genetic diversity of class D oxacillinases, including OXA-23, -24 (-40), -58 and, particularly, the intrinsic OXA-51-like genes, among multidrug-resistant (MDR) Acinetobacter baumannii strains from inpatients at a tertiary care hospital in Riyadh, Saudi Arabia. Sequence-based typing (SBT) of the OXA-51-like gene was carried out on 253 isolates. Selected isolates (n = 66) were subjected to multilocus sequence typing (MLST). The polymerase chain reaction (PCR) typing results showed that all isolates (n = 253) contained the OXA-51-like and OXA-23 genes. However, the OXA-58 gene was detected in five isolates. Further, none of the isolates had the OXA-40 (identical to the OXA-24) gene. SBT revealed a high OXA-51-like genotypic diversity and showed that all isolates were clustered into four main groups: OXA-66 (62.3 %), followed by OXA-69 (19.1 %), OXA-132 (7.6 %) and other OXA-51-like genes (10.3 %), including OXA-79, -82, -92, -131 and -197. MLST revealed four main sequence types (STs), 2, 19, 20 and 25, among the isolates, in addition to six isolates with newly designated ST194-ST197 singletons. Further, a high prevalence (81.4 %) of OXA-66 and OXA-69-like genes in A. baumannii was identified. More studies are essential in order to explore the molecular mechanisms that confer carbapenem-resistant phenotypes for A. baumannii isolates and to investigate the genetic diversity of other OXA-D genes.

Epidemiology of Acinetobacter spp.-associated healthcare infections and colonization among children at a tertiary-care hospital in Saudi Arabia: a 6-year retrospective cohort study.

A retrospective cohort study was conducted among hospitalized children less than 12 years of age who had Acinetobacter spp. isolated from ≥1 cultures between October 2001 and December 2007 at King Abdulaziz Medical City in Riyadh, Saudi Arabia. Children with multidrug-resistant (MDR) Acinetobacter spp. healthcare-associated infections (HAIs) were compared to children with antimicrobial-susceptible Acinetobacter spp. HAIs and to children colonized with Acinetobacter. Children with MDR Acinetobacter spp. HAIs were older (p = 0.01), more likely to be admitted to an intensive care unit (ICU) (p = 0.06), and had a higher mortality rate (p = 0.02) than colonized children. Children with MDR Acinetobacter spp. HAIs were older than children with antimicrobial-susceptible Acinetobacter spp. HAIs (p = 0.0004), but their mortality rates were similar. Among children with MDR Acinetobacter spp. HAIs, burn injuries were the most common underlying illness. HAIs caused by MDR or susceptible Acinetobacter spp. occurred after prolonged hospitalization, suggesting nosocomial acquisition. Patients infected with MDR Acinetobacter spp. frequently received inappropriate empiric therapy (73.9 %). Further studies are needed in order to identify effective strategies to prevent nosocomial transmission and effective ways of improving patient outcomes.

The epidemiology of the first described carbapenem-resistant Klebsiella pneumoniae outbreak in a tertiary care hospital in Saudi Arabia: how far do we go?

The purpose of this investigation was to describe the first documented carbapenem-resistant Klebsiella pneumoniae (CRKP) outbreak in a tertiary care facility in Saudi Arabia. We initiated a prospective study to follow all cases of CRKP as well as the active surveillance of patients in areas where cases were identified. We also conducted a retrospective review of the microbiology database for any missed cases of CRKP. Pulsed field gel electrophoresis (PFGE) was conducted for the available CRKP isolates. During March 2010, a cluster of eight CRKPs was detected primarily in the adult intensive care unit (ICU). Patients with CRKPs were put under strict contact isolation, along with appropriate infection control measures. A retrospective review of K. pneumoniae isolates over the previous 6 months revealed two more CRKPs. The PFGE results during the outbreak period showed that the majority of strains were genetically indistinguishable or closely related. The majority of patients had prolonged hospital stay (91%), indwelling devices (81%), surgical procedures (74%), carbapenem use (62%), and colonization/infection with other multiple drug-resistant organisms (MDROs) (57%). Two-fifths of patients with CRKP had clinical infection and 38% died during the current hospitalization. Contact isolation, hand hygiene, environmental cleaning, and staff education may control CRKP outbreak in the acute care setting, but did not prevent endemicity.

Public attitude towards biomedical research at outpatient clinics of King Abdulaziz Medical City, Riyadh, Saudi Arabia.

The aim of this study was to determine the attitude of Saudi Arabians to research involving storage and use of human tissues from which genetic information may be derived and to assess their willingness to donate tissue samples to biobanks. In a cross-sectional interview study of 1051 outpatients at a hospital in Riyadh city, 68.8% had a positive attitude towards biomedical research and 78.4% were willing to allow use of excess surgical tissues for research purposes. Participants were less willing to allow the use of tissue or organs from a deceased relative. Logistic regression analysis found that predictors for a positive attitude to biomedical research and to use of tissue in research were: female sex, higher level of education, previous experience of blood testing and previous participation in health-related research. The attitudes towards biomedical research among the participants were satisfactory and comparable to findings from other countries.

Public attitude towards biomedical research at outpatient clinics of King Abdulaziz medical city, Riyadh, Saudi Arabia

The aim of this study was to determine the attitude of Saudi Arabians to research involving storage and use of human tissues from which genetic information may be derived and to assess their willingness to donate tissue samples to biobanks. In a cross-sectional interview study of 1051 outpatients at a hospital in Riyadh city, 68.8% had a positive attitude towards biomedical research and 78.4% were willing to allow use of excess surgical tissues for research purposes. Participants were less willing to allow the use of tissue or organs from a deceased relative. Logistic regression analysis found that predictors for a positive attitude to biomedical research and to use of tissue in research were: female sex, higher level of education, previous experience of blood testing and previous participation in health-related research. The attitudes towards biomedical research among the participants were satisfactory and comparable to findings from other countries

Methicillin-resistant Staphylococcus aureus: a 5-year review of surveillance data in a tertiary care hospital in Saudi Arabia.

BACKGROUND: Staphylococcus aureus is an important pathogen that leads to serious infections in the community and in hospitals. Evidence has shown that the prevalence of infection and colonization with drug-resistant S. aureus, such as methicillin-resistant S. aureus (MRSA) and glycopeptide intermediately susceptible S. aureus, is increasing. Authorities must be aware of the prevalence of MRSA infection and colonization in their country in order to implement and monitor infection control policies that help curtail further emergence of this pathogen. OBJECTIVES: To examine the trend of hospital-acquired MRSA infection and colonization in a tertiary care institution in Saudi Arabia during a 5-year period in order to identify specific areas at high risk for MRSA transmission, and to review our MRSA decolonization procedure and outcomes. METHODS: Surveillance data prospectively collected from January 1, 2000, through December 31, 2004, on hospital-acquired (HA) MRSA were analyzed, with an emphasis on the trend of HA-MRSA infection and colonization, areas of high transmission, risk factors, and effectiveness of the implemented decolonization policy. RESULTS: During the study period, 442 cases of HA-MRSA infection and colonization were identified. Of these, 51.2% were infections, and 48.8% were colonizations. An increasing trend in the incidence rates of infection and colonization was noticed during the study period, and most cases were identified on the surgical ward (33.3%) and medical ward (32.1%). Of the 34 infected patients who underwent systematic decolonization, 35.3% were successfully decolonized, and of the 11 who underwent topical decolonization, 63.6% were successfully decolonized. CONCLUSION: The increasing trend of HA-MRSA infections has been a noticeable global problem. We identified a gradual increase in the rates of MRSA colonization and infection in a tertiary care center Saudi Arabia and recognize the importance of abiding by strict infection control policies, including hand hygiene and proper isolation practices. Continued surveillance for MRSA and other emerging multidrug-resistant pathogens is also needed.

Seroprevalence survey of varicella, measles, rubella, and hepatitis A and B viruses in a multinational healthcare workforce in Saudi Arabia.

OBJECTIVE: To determine the prevalence of the vaccine-preventable diseases caused by varicella, measles, rubella, and hepatitis A and B viruses in a multinational healthcare workforce. DESIGN: Prospective cohort study. SETTING: A 750-bed tertiary care center located in Riyadh, Saudi Arabia. METHODS: In compliance with hospital policy, newly recruited healthcare workers (HCWs) were enrolled in the study from September 2001 to March 2005. Serum samples were collected from all HCWs during the initial hiring process and tested for IgG antibodies against each of the 5 viral agents. Nonimmune HCWs were subsequently vaccinated at the earliest opportunity. RESULTS: A total of 4,006 newly hired (international and local) employees were included in the study. All underwent serologic testing for IgG antibodies against varicella, measles, rubella, hepatitis A, and hepatitis B viruses. Of the total, 63% were female and 37% were male. Middle Eastern employees comprised 47% of the total, followed by employees from the Far East (35%), the West (10%), and Africa (8%). Forty-two percent were nurses, 27% were in administration, 18% were medical technicians, and 13% were physicians. Among the 4,006 newly hired HCWs, 14% had negative IgG antibody test results for varicella virus, 13% for measles virus, 10% for rubella virus, 33% for hepatitis A virus, and 43% for hepatitis B virus. More women than men were susceptible to hepatitis A (40% vs. 24%; P<.001), whereas more men were susceptible to hepatitis B (55% vs. 35%; P<.001). Varicella susceptibility was more common among HCWs from the Far East (19%), whereas susceptibility to measles, rubella, hepatitis A, and hepatitis B was highest among HCWs from the Middle East. Both relative youth and male sex were associated with lack of antibodies against hepatitis B virus and rubella virus. In contrast, female sex and younger age were associated with lack of antibodies against hepatitis A virus (P<.001). CONCLUSION: Seroprevalence surveys of vaccine-preventable diseases among HCWs, although labor intensive, are invaluable in caring for a multinational workforce.

Epidemiologic shift in the prevalence of Hepatitis A virus in Saudi Arabia: a case for routine Hepatitis A vaccination.

This study aims to determine the seroprevalence of Hepatitis A among a selected group of Saudi children and thus, identify the best immunization strategy. A school-based seroprevalence study in children 4-18 years of age attending the National Guard schools was done. Of the 25,531 children attending the National Guard schools, 2399 (10%) were randomly selected through a stratified one-stage cluster survey. The overall prevalence of HAV-IgG was 28.9%. The prevalence was almost the same in male and female (28.2% versus 29.5%, respectively). There was a gradual increase in the HAV-IgG with 7% in children (< 8 years), 14% (8-11 years), 30% (12-15 years), and 52% (> 16 years) of age. Since a substantial proportion of this pediatric population confirms a continuing decrease in anti-HAV seroconversion rates, we recommend including Hepatitis A in the schedule of routine childhood vaccinations.

Rate, risk factors and outcomes of catheter-related bloodstream infection in a paediatric intensive care unit in Saudi Arabia.

The aim of this study was to determine the rate, risk factors and outcomes of catheter-related bloodstream infections (CRBSIs) in patients in a paediatric intensive care unit (PICU). A prospective cohort study was performed in King Abdulaziz Medical City, Riyadh, Saudi Arabia; a 650-bed academic/tertiary care centre with a combined 10-bed medical and surgical PICU. All patients admitted to the PICU from July 2000 to February 2003 who had a central line placed were monitored for the development of bloodstream infection (BSI) from insertion until 48 h after removal. Four hundred and forty-six patients with 2493 central-line-days were documented; 273 (55%) were male and the mean age was 2.6 years. Of the 446 patients, 278 (56%) had congenital heart disease, 108 (22%) had genetic disorders and/or congenital malformations, 55 (11%) had respiratory disease, and 42 (8%) had trauma. There were 50 episodes of CRBSI in 46 patients with a rate of 20.06 per 1,000 central-line-days and a device-utilization rate of 57%. Of these 50 episodes, 24 (48%) were polymicrobial, 16 (32%) were due to Gram-negative organisms, five (10%) were due to Gram-positive organisms, and five (10%) were fungal. The most common organisms isolated were Klebsiella pneumoniae (N=12, 16%), coagulase-negative staphylococci (N=10, 14%) and Pseudomonas aeruginosa (N=8, 11%). The mean duration of line insertion was 11.8 days for CRBSI patients and 4.22 days for non-BSI patients (P<0.0001). The mean PICU stay was 30.20 days for CRBSI patients and 6.35 days for non-BSI patients (P<0.0001). BSI occurred more often in catheters inserted in the PICU compared with the operating room, and in the femoral site compared with jugular or subclavian sites (P<0.001). In multiple logistic regression analysis of the risk factors, CRBSI patients were more likely to have multiple central lines [odds ratio (OR) 9.19; 95% confidence intervals (CI): 3.76-22.43), the line was more likely to be used for total parenteral nutrition (OR: 8.69; 95% CI: 3.5-21.4), and guidewire exchange was more likely to be performed on the line. CRBSI was not associated with a higher mortality rate. The CRBSI rate in our hospital is high compared with that reported by the National Nosocomial Infection Surveillance system. This study has established a benchmark for future comparisons. Additional studies from Saudi Arabia are necessary for national comparison and development of preventive measures.

In vitro activity of quinolones against S. pneumoniae, H. influenzae and M. catarrhalis in Saudi Arabia.

Susceptibility of 88 clinical Streptococcus pneumoniae isolates, 116 Haemophilus influenzae isolates and 80 Moraxella catarrhalis isolates to 6 fluoroquinolones--ciprofloxacin, ofloxacin, levofloxacin, trovafloxacin, grepafloxacin and gemifloxacin--were determined. Isolates were from patients with invasive disease at 4 hospitals in Saudi Arabia between 1996 and 1998. S. pneumoniae isolates were fully susceptible to trovafloxacin, grepafloxacin and gemifloxacin; susceptibility to ofloxacin and levofloxacin was 97.7% and 98.9% respectively. H. influenzae isolates were susceptible to all agents, except for trovafloxacin (99.1%). M. catarrhalis strains were fully sensitive to all agents except ofloxacin (97.5%). No isolates were resistant to gemifloxacin or grepafloxacin.

In vitro activity of quinolones against S. pneumoniae, H. influenzae and M. catarrhalis in Saudi Arabia

Susceptibility of 88 clinical Streptococcus pneumoniae isolates, 116 Haemophilus influenzae isolates and 80 Moraxella catarrhalis isolates to 6 fluoroquinolones--ciprofloxacin, ofloxacin, levofloxacin, trovafloxacin, grepafloxacin and gemifloxacin--were determined. Isolates were from patients with invasive disease at 4 hospitals in Saudi Arabia between 1996 and 1998. S. pneumoniae isolates were fully susceptible to trovafloxacin, grepafloxacin and gemifloxacin; susceptibility to ofloxacin and levofloxacin was 97.7% and 98.9% respectively. H. influenzae isolates were susceptible to all agents, except for trovafloxacin [99.1%]. M. catarrhalis strains were fully sensitive to all agents except ofloxacin [97.5%]. No isolates were resistant to gemifloxacin or grepafloxacin

Importance of screening household members of acute brucellosis cases in endemic areas.

Isolated reports of brucellosis among family members have been documented. The aim of this study is to determine if active serological screening of the households' members of acute brucellosis cases will detect additional unrecognized cases. From May 2000 to October 2001, patients with acute brucellosis were enrolled and their household members were serologically screened for brucellosis using the Standard Agglutination Test (SAT). Fifty-five index cases with acute brucellosis and 404 household members were enrolled. The majority of index cases (48%) were young adults, and 79% were illiterate. Ownership of animals and ingestion of unpasteurized raw milk were reported by 45 and 75% of the index cases respectively. Of the 55 families screened, 23 (42%) had two family members or more with serological evidence of brucellosis and 32 (58%) had only the index case. Households of > or = 5 members and a history of raw-milk ingestion by family members were risk factors associated with the seropositives (P < 0.05). Of the 404 household members screened, 53 (13%) were seropositive; of these 39 (74%) were symptomatic, and 9 (35%) had brucella bacteraemia. Symptomatic seropositives tended to have bacteraemia and higher brucella antibody titres compared to asymptomatic seropositives (P < or = 0.05). Screening family members of an index case of acute brucellosis will detect additional cases.

Brucella melitensis bacteremia in children: review of 62 cases.

Brucella bacteremia is not uncommon in children living in endemic areas. Reports on brucella bacteremia, however, are scarce. Its clinical features and complications are unknown. This retrospective review describes the clinical and laboratory characteristics, the relapse rate, and response to different regimens of antimicrobials in children with brucella bacteremia over a 5-year period. Antimicrobial susceptibility testing was performed on all isolates. Data on 62 children with brucella bacteremia were collected between 1996 and 2000. All isolates were of Brucella melitensis species. Most children were between five and 10 years of age; males were twice as affected as females (66% vs 34%). Fever and arthralgia were the most common presenting symptoms, 81% and 48% respectively. Fever and arthritis were the most common physical findings, 81% and 19% respectively. Forty-five (73%) patients presented within 10 days of illness onset. Brucella titers were measured in all patients; 95% had a positive titer of 1:320 or more. Resistance to co-trimoxazole (sulfamethoxazole + trimethoprim) increased from 22% in 1996 to 66% in year 2000. Rifampicin and co-trimoxazole were the most commonly used combination in 50%, rifampicin, co-trimoxazole, supplemented with gentamicin or streptomycin in 27%. The median duration of therapy was 6 weeks. The overall relapse rate was 13% (95% CI, 4.6%-21.2%) but was higher among those with symptoms lasting >10 days (P<0.001). There was a high relapse rate among patients infected with co-trimoxazole-resistant species and treated with co-trimoxazole compared to patients infected with sensitive species who also received co-trimoxazole (22% vs. 8%), but this was not statistically significant (P = 0.16). Patients with brucella bacteremia present early in their course of illness. Their clinical features, however, did not differ from brucellosis patients who did not have bacteremia. Despite the high rate of in-vitro resistance to co-trimoxazole, this did not correlate with a significant relapse rate.

Severe La Crosse encephalitis with significant neurologic sequelae.

La Crosse encephalitis, a member of the California arbovirus group, is the most common cause of reported mosquito-borne illness in the United States. Approximately 70 cases of La Crosse encephalitis are reported each year. The principal vector is the mosquito Aedes triseriatus. During the summer the virus is amplified horizontally in a cycle among small mammals such as chipmunks and squirrels. Infected female A. triseriatus deposit eggs in the basal holes of hardwood trees, although man-made containers and old tires containing water also supply a suitable breeding site. Some of these eggs infected with La Crosse virus hatch the next spring and give rise to infected adult A. triseriatus, and the host-vector cycle is renewed. Only a minority of children infected with the virus become ill. Clinical disease caused by La Crosse is usually mild, and neurologic sequelae are relatively uncommon. In this report we describe six patients with severe La Crosse meningoencephalitis diagnosed within a 4-week period. All patients required intensive care management, and there was a high rate of neurologic sequelae, suggesting that La Crosse is not necessarily a benign meningoencephalitis.

Endotoxin fails to induce IFN-gamma in endotoxin-tolerant mice: deficiencies in both IL-12 heterodimer production and IL-12 responsiveness.

Mice exposed to sublethal endotoxemia develop short-term endotoxin tolerance, a state characterized by decreased monokine production and enhanced protection against endotoxic lethality. We confirmed that TNF-alpha production is markedly impaired in endotoxin-tolerant mice and additionally found 2- to 6-fold decreases in serum IFN-gamma in these animals following endotoxin challenge. The IFN-gamma deficiency of endotoxin tolerance correlated with 8-fold decreases in the bioactive p40/p35 heterodimeric form of IL-12. In contrast, total circulating IL-12 p40 was reduced by only 30-50%. Endotoxin-tolerant mice were less responsive to IL-12 than control mice, as evidenced by 3-fold lower levels of IFN-gamma inducible in vivo when rIL-12 was administered at the time of endotoxin challenge. Similarly, spleen cell cultures of endotoxin-tolerant mice produced 3-fold less IFN-gamma in the presence of optimal concentrations of both IL-12 and IL-18. Finally, levels of IL-12R beta 2 subunit mRNA and the percent composition of NK lymphocytes in the spleen were both decreased in endotoxin-tolerant mice relative to controls. We conclude that endotoxin-tolerant mice are profoundly impaired in their ability to produce IFN-gamma in response to endotoxin and that this is associated with acquired defects in both the production of circulating IL-12 heterodimer response and the response to IL-12 by NK cells.

Parvovirus: a review.

Infections caused by human parvovirus B19 result in a variety of clinical manifestations, the severity of which depends on the immune and hematologic status of the host. Arthropathy is known to occur in children and adults with acute parvovirus B19 infection. In adults, the arthropathy is common and is usually brief and self-limited, although a chronic arthropathy due to HPV B19 infections can occur rarely. It is important to differentiate between such chronic infection and RA, because of the similar clinical manifestations and different modes of treatment. An association between HPV B19 and other rheumatologic diseases such as vasculitis needs further research before confirmation is possible.

Screening carotid ultrasonography and risk factors for stroke in coronary artery surgery patients.

BACKGROUND: The role of noninvasive carotid artery screening in relation to other clinical variables in identifying patients at increased risk of stroke after coronary artery bypass grafting was examined. METHODS: Preoperative, intraoperative, and postoperative clinical data were prospectively collected for 1,835 consecutive patients undergoing first-time isolated coronary artery bypass grafting between March 1990 and July 1995, 1,279 of whom had screening carotid ultrasonography. All patients with postoperative neurologic events were identified and reviewed in detail. Average patient age was 65.3 years (range, 33 to 92 years), and 9.3% (171 patients) had a prior permanent stroke or transient ischemic attack. Hospital and 30-day mortality was 2.2% (41 patients). Forty-five patients (2.5%) had a transient or permanent postoperative neurologic event. The data were analyzed by stepwise logistic regression to determine the independent predictors of both significant carotid stenosis and stroke. RESULTS: On multivariate analysis, the clinical predictors of significant carotid stenosis were age (p < 0.0001), diabetes (p = 0.0123), female sex (p = 0.0026), left main coronary stenosis greater than 60% (p < 0.0001), prior stroke or transient ischemic attack (p = 0.0008), peripheral vascular disease (p = 0.0001), prior vascular operation (p = 0.0068), and smoking (p < 0.0001). When all variables were evaluated for those patients who underwent noninvasive carotid artery screening, the independent predictors of postoperative neurologic event were prior stroke or transient ischemic attack (p < 0.0001), peripheral vascular disease (p = 0.0037), postinfarction angina pectoris (p = 0.0319), postoperative atrial fibrillation (p = 0.0014), carotid stenosis greater than 50% (p = 0.0029), cardiopulmonary bypass time (p = 0.0006), significant aortic atherosclerosis (p = 0.0054), postoperative amrinone or epinephrine use (p = 0.0054), and left ventricular ejection fraction less than 0.30 (p = 0.0744). CONCLUSIONS: The etiology of postoperative stroke is multifactorial. Selective use of carotid ultrasonography is of value in identifying patients who are at greater risk of postoperative stroke independent of other variables and should be considered before coronary artery bypass grafting, particularly in patients with a history of neurologic event or peripheral vascular disease.