Short link N acts as a disease modifying osteoarthritis drug.

Osteoarthritis (OA) is a degenerative joint disease characterised by a progressive degradation of articular cartilage and underlaying bone and is associated with pain and disability. Currently, there is no medical treatment to reverse or even retard OA. Based on our previous reports, where we establish the repair potential of short Link N (sLN) in the intervertebral disc, a cartilage-like tissue, we hypothesise that sLN may hold similar promises in the repair of articular cartilage. This study aimed to determine if sLN, could prevent OA disease progression. Skeletally mature New Zealand white rabbits underwent unilateral anterior cruciate ligament transection (ACLT) of their left femorotibial joints to induce joint degeneration typical of OA. Beginning 3 weeks post-operatively, and every three weeks thereafter for 12 weeks, either saline (1 mL) or sLN (100 µg in 1 mL saline) was injected intraarticularly into the operated knee. Six additional rabbits underwent sham surgery but without ACLT or post-operative injections. The effects on gross joint morphology and cartilage histologic changes were evaluated. In the Saline group, prominent erosion of articular cartilage occurred in both femoral condyle compartments and the lateral compartment of the tibial plateau while, sLN treatment reduced the severity of the cartilage damage in these compartments of the knee showing erosion. Furthermore, statistically significant differences were detected between the joint OA score of the saline and sLN treated groups (p = 0.0118). Therefore, periodic intraarticular injection of sLN is a promising nonsurgical treatment for preventing or retarding OA progression, by reducing cartilage degradation.

Osteocutaneous free flaps for mandibular reconstruction: systematic review of their frequency of use and a preliminary quality of life comparison.

OBJECTIVES: To determine whether the fibula free flap is the most frequently used osteocutaneous flap for mandible reconstruction, and whether it provides quality of life, depression and anxiety advantages. METHODS: A systematic review of the public Medline database was conducted. Thirteen patients who underwent mandibular reconstruction at our hospital centre completed questionnaires to evaluate quality of life, depression and anxiety outcomes. RESULTS: The most frequently used free flaps are those of the fibula (n = 982), radial forearm (n = 201), iliac crest (n = 113), subscapular system (n = 50) and rib-serratus (n = 7). In our patient population, there was a trend towards a better quality of life in those with a fibula free flap. However, patients in this group were significantly younger than patients with other flap types (p = 0.025). Patients with a subscapular system free flap were more depressed (p = 0.031); however, they had large through-and-through defects. CONCLUSION: The flap used most frequently in the literature is the fibula free flap. Comparative quality of life data are lacking, and homogeneous populations should be used to reach significant conclusions.

International prospective evaluation of scintimammography with technetium-99m sestamibi: interim results.

OBJECTIVE: The purpose of this study is to evaluate the validity and reliability of scintimammography with technetium-99m (99mTc)-labeled sestamibi as an adjunct radiodiagnostic agent in the diagnosis of breast cancer. METHODS: This is a multicenter prospective cohort clinical trial that was initiated in June 1999 and will terminate May 2001. All patients with a physical or mammographic finding visiting any of the participating clinics are enrolled in the study. Patients who are younger than 18 years, pregnant, not willing to sign the consent form, or who have undergone an invasive procedure on the breast 30 days or less before scintimammography are excluded. At the time of the first interim report, 633 patients had been recruited from six Canadian centers. To date complete data have been collected for 530 patients. RESULTS: The mean (SD) age of the patients is 56 (12) years with a range between 24 and 85. There were 122 (23%) of the women in the sample who were postmenopausal and 36 (7%) who were perimenopausal. Breast density was graded as dense for 127 (24%), normal for 260 (50%), and fatty for 138 (26%). Of the 530 women in the study 156 (29%) had a palpable mass at physical examination. The mammographic results were classified as 76 (14%) breast imaging reporting and data system (BIRADS) 5, 60 (11%) BIRADS 4, 70 (13%) BIRADS 3 and the remaining BIRADS 2 or 1. The scintimammography results were positive for 118 (23%) of the patients and negative for 412 (78%). The histopathology showed malignant breast disease for 66 (12.5%) of the patients in the sample. Sensitivity and specificity of scintimammography for the detection of breast cancer was estimated 90.9% and 87.5%, respectively. A positive predictive value (PPV) of 50.8% with a negative predictive value of 98.5% and an accuracy of 87.5% were calculated. The PPV is interpreted as the posttest probability of disease given a positive test result. In this sample the pretest probability of disease would be best estimated by the prevalence of disease, which is equal to 12.5%. A positive scintimammography result would change the estimated probability to 51%, which is equivalent to a 400% change from the pretest value. Therefore a positive scintimammography result significantly increases our ability to predict the presence of malignant disease in this population. CONCLUSION: The interim results of the present study suggest that scintimammography with 99mTc-sestamibi is accurate and potentially useful as an adjunct to mammography for the detection of breast cancer.

Impact of waiting time on the quality of life of patients awaiting coronary artery bypass grafting.

BACKGROUND: A lack of resources has created waiting lists for many elective surgical procedures within Canada's universal health care system. Coronary artery bypass grafting (CABG) for the treatment of atherosclerotic ischemic heart disease is one of these affected surgical procedures. We studied the impact of waiting times on the quality of life of patients awaiting CABG. METHODS: A prospective cohort of 266 patients from 3 hospitals in Montreal was used. Patients who gave informed consent were followed from the time they were registered for CABG until 6 months after surgery; recruitment began in November 1993, and the last follow-up was completed in July 1995. Patient groups were classified according to the duration of the wait for CABG (< or = 97 days or > 97 days). We measured the following outcomes: quality of life (using the Medical Outcomes Study 36-item Short Form [SF-36]), incidence of chest pain (using the New York Heart Association angina classification), frequency of symptoms (using the Cardiac Symptom Inventory) and rates of complications and death before and after surgery. RESULTS: There were no differences in quality of life at baseline between the 2 groups. Immediately before surgery, compared with patients who waited 97 days or less, those who waited longer had significantly reduced physical functioning (change from baseline SF-36 score 0 v. -4 respectively, p = 0.001), vitality (change from baseline score -0.1 v. -1.3, p = 0.01), social functioning (change from baseline score 0.4 v. -0.4, p = 0.03) and general health (change from baseline score 1.1 v. -1.7, p = 0.001). At 6 months after surgery, compared with patients who waited 97 days or less for CABG, those who waited longer had reduced physical functioning (change from baseline SF-36 score 4.0 v. -0.1 respectively, p = 0.001), physical role (change from baseline score 0.8 v. 0.0, p = 0.001), vitality (change from baseline score 2.2 v. 0.9, p = 0.001), mental health (change from baseline score 1.2 v. 0.0, p = 0.001) and general health (change from baseline score 1.8 v. -0.3, p = 0.001). The incidence of postoperative adverse events was significantly greater among the patients with longer waits for CABG than among those with shorter waits (32 v. 14 events respectively, p = 0.005). Longer waits before CABG were associated with an increased likelihood of not returning to work after surgery (p = 0.08): 10 (53%) of the 19 patients with longer waiting times remained employed after CABG, as compared with 17 (85%) of the 20 with shorter waiting times. INTERPRETATION: The significant decrease in physical and social functioning, both before and after surgery, for patients waiting more than 3 months for CABG is an important observation. Longer waiting times were also associated with increased postoperative adverse events. By decreasing waiting times for CABG, we may improve patients' quality of life and decrease the psychological morbidity associated with CABG.

Cardiopulmonary resuscitation: errors made by pre-hospital emergency medical personnel.

The purpose of the current study was to evaluate the CPR techniques of emergency healthcare professionals (emergency medical technicians, firemen, emergency first responders, CPR instructors). Skills were evaluated using a Laerdal Skillmeter Manikin, which provided a computerized printout of the quantifiable data during the CPR sequence. All of the 66 subjects in the study had completed a recertification course within the last 2 years (mean = 0.86 +/- 0.18, 95% CI). The sequence was videotaped for later viewing and for correlating the errors with the data. In addition, the participants were required to fill in a questionnaire. The most frequently occurring errors were observed in landmarking, overcompression, palpating a carotid pulse and insufficient ventilation. Although 98.5% of participants made an attempt to landmark their position for compression on the sternum, 35.9% of the total compressions performed by all subjects were incorrectly positioned on the patient's chest. Overcompression of the patient's chest accounted for 55.3% of incorrect compressions. Although 94% of participants attempted to verify a carotid pulse, only 45% were able to feel it and therefore stop performing cardiac massage. Of the total ventilations, 49% were below the American Heart Association (AHA) recommended minimum (800 ml). The results of this study showed a high rate of errors occurring in the CPR provided by emergency healthcare professionals.

Measuring postoperative complications in general surgery patients using an outcomes-based strategy: comparison with complications presented at morbidity and mortality rounds.

BACKGROUND: This study was undertaken to compare the incidence of adverse postoperative outcomes recorded in a prospective general surgery database with that identified through weekly morbidity and mortality (M&M) rounds and to measure the impact of feedback of information to the providers of care. METHODS: Data were collected on patients admitted to one general surgery service between October 1, 1995, and May 15, 1996, and recorded in a computer database. Postoperative complications were graded in severity from I (minor) to IV (mortality). RESULTS: Of 479 admissions entered into the database during the study period, 325 (311 patients) led to operations and were further analyzed. Admissions resulting in complications were associated with longer hospital stays, regardless of complication grade, compared to uncomplicated admissions (p < 0.01). A total of 29 of 106 patients with postoperative complications were presented at M&Ms (27.4%). Whereas 15.4% of database patients with grade I complications were presented at M&Ms, this proportion increased to 22.2% for grade IIa, 34.8% for grade IIb, 33.3% for grade III, and 87.5% for grade IV. (p < 0.05 for grade I, IIa, and IIb compared to grade IV). A total of 58 of 142 patients in the first part of the study period developed complications (40.8%), compared to 53 of 183 patients in the second part of the study (29%, p = 0.034). CONCLUSIONS: Although most severe complications are recorded at M&M rounds, a large proportion of complications remain unreported. Monitoring of outcomes may contribute to improvements in quality of care.

Ultrasound in the assessment of cranial bone thickness.

Preoperative knowledge of skull thickness before harvesting cranial bone grafts would be ideal to help minimize intracranial complications. Previous research has demonstrated regional variations in calvaria; however, accurate preoperative and intraoperative methods of skull thickness measurement are not available. The aim of this research represents the first attempt to examine the reliability of ultrasound to determine cranial bone thickness. Four previously studied calvarial sites were marked in 10 adult male cadaveric skulls. The individual points were insonified using an A-mode ultrasonic transducer operating in pulse-echo mode. The times of flight of the waves propagating in the bone samples were compared with caliper measurements. The mean difference in cranial bone thickness was 0.16 mm, with a standard deviation of 0.09 mm. Student's t-test failed to reveal any statistically significant differences between caliper and ultrasonic measurements (p = 0.569) and Pearson's correlation coefficient supported an extremely strong and positive relationship between the two modalities (r > 0.992). Multiple linear regression models predicted that calvarial thickness could be accurately predicted by ultrasound without consideration of cadaveric specimen or sampling point location (R2 = 0.988). The convergent values between ultrasonic and caliper measurements suggest that this modality can accurately and reliably determine skull thickness. A-mode ultrasound can have significant implications in guiding the harvest of in situ split cranial bone grafts, the placement of osseointegrated implants, skull anthropometrics, and related craniomaxillofacial applications.

Perioperative mortality after pneumonectomy: analysis of risk factors and review of the literature.

OBJECTIVE: To determine risk factors for perioperative death associated with pneumonectomy. DESIGN: A retrospective case-control study in which a perioperative death group was compared with a survivor group, and a review of the English literature on the subject. SETTING: The Montreal General Hospital, a tertiary-care teaching institution. PATIENTS AND INTERVENTION: Ninety-two consecutive patients who underwent pneumonectomy between April 1989 and 1994. MAIN OUTCOME MEASURES: The effects of age, sex, smoking history, tumour size, type and stage, pulmonary function, cardiovascular risks, comorbidity, preoperative blood values and volume of fluids administered perioperatively. Values from the literature were reported for comparison. RESULTS: The perioperative death rate was 10.9%. Selection bias and in-hospital values reported in the literature have underestimated the death rate, with actual rates ranging from 7% to 11%. Age (odds ratio 2.48, p = 0.04), the presence of 1 or more comorbid diseases (odds ratio 7.92, p = 0.05) and amount of fluids given in the first 12 hours postoperatively (odds ratio 2.21, p = 0.06) were found to be significant risk factors for death. Multivariate logistic regression demonstrated that the volume of fluids given remains an independent risk factor whereas age and comorbid disease are dependent variables. CONCLUSIONS: The results were consistent with previously reported death rates and risk factors. Patient age and concomitant disease are not modifiable risk factors, but perioperative fluid administration and other means to prevent postpneumonectomy pulmonary edema may reduce the perioperative death rate.

Risk factors for adult Still's disease.

OBJECTIVE: To assess risk factors for adult Still's disease (ASD). METHODS: A matched case-control study of 60 patients with ASD and 60 same sex siblings closest in age was conducted. Subjects were recruited from cohorts in Eastern Canada, Pittsburgh, and the Arthritis, Rheumatism, and Aging, Medical Information Systems (ARAMIS). A questionnaire was used to obtain data on demographic characteristics, education, income, occupation, exposure to toxic substances, stress, and medical history. RESULTS: 116 patients with ASD were identified, of which 104 participated. 86 identified same sex siblings, of which 60 replied. When compared to same sex siblings, ASD patients were similar with respect to education and occupation but had a trend to higher median income. There were no significant associations of ASD with smoking, alcohol consumption, individual toxic substances, vaccination, blood transfusion, minor or major surgery, pregnancy, or diet in the year preceding disease onset. There were no significant associations with tonsillectomy or adenoidectomy, appendectomy, asthma, hay fever, allergy shots, or pregnancy at any time preceding the onset of disease. There was a statistically nonsignificant increase in a history of exposure to coal dust [odds ratio (OR) 3.0; 95% confidence interval (CI) 0.30 to 28.84], in allergy preceding the onset of disease (OR 2.67; 95% CI 0.71 to 10.05), and in oral contraceptive use in the year preceding onset (OR 2.00; 95% CI 0.18 to 22.06). Stressful life events (OR 2.56; 95% CI 1.18 to 5.52) in the year preceding onset was significantly associated with increased risk for ASD. This positive association should be treated with caution unless confirmed by a separate study. CONCLUSION: This exploratory study of risk factors for ASD draws attention to stress as a potentially important risk factor, while likely excluding a considerable number of others.

Predictive validity and internal consistency of the pre-hospital index measured on-site by physicians.

Physiological measures of injury are used as triage tools to identify patients that require treatment in trauma centres. The Pre-Hospital Index (PHI) is based on systolic blood pressure, pulse, respiratory rate, (level of) consciousness, and presence of penetrating injury. The present study evaluated the validity and internal consistency of the PHI. The study was based on 628 patients assessed by physicians at the scene. Mean age was 38.7 years (SD = 24.8), and 65% were male. Motor vehicle collisions caused the injury for 45%. The majority had head/neck (56%) and extremity (45%) injuries. Mean PHI was 4.62 (SD = 5.77), 40% had a PHI of zero, 6% between 1 and 3, 32% between 4 and 7, and 21% greater than 7. The associations between PHI and rates of hospital admission, surgery, ICU treatment, mortality, duration of hospitalization, and length of ICU stay were significant (p < 0.001). A total of 260 (41.4%) patients had major trauma requiring treatment at a trauma centre. A PHI > 3 had 83% sensitivity and 67% specificity for identifying these patients. Internal consistency of the PHI variables was above the acceptable limits. This study has shown that the PHI is a valid and reliable physiological measure of injury severity and field triage tool.

Human breast cancer: genetic alterations in the MET gene region.

OBJECTIVE: to test whether the MET gene at chromosome 7q31, which encodes a receptor protein (tyrosine kinase) related to normal histological differentiation, undergoes structural changes in breast cancer. A previous study reported somatic alterations detected as loss of heterozygosity (LOH) at this locus in breast cancer. DESIGN: Analysis of DNA from tumours and matched normal tissue by Southern blot hybridization with the metH probe; the tumours were also analysed for estrogen and progesterone receptors, ploidy and S phase, and protein expression of the MET and c-erbB-2 protooncogenes. PARTICIPANTS: Eighty-two patients with breast cancer. RESULTS: Fifty-three percent of the patients were informative for polymorphism with the metH marker. Somatic alterations of MET, consisting of LOH, were demonstrated in 22% of women who were informative and had breast cancer. No correlation was found between LOH of MET and conventional prognostic factors, or status for c-erbB-2 proto-oncogene expression. Estrogen-receptor status correlated with progesterone-receptor status, and S phase correlated with ploidy and size of the tumour. CONCLUSIONS: Somatic alterations of MET, detected as LOH with the metH probe, occur in 22% of informative patients. These alterations do not correlate with the prognostic factors established when the mastectomy is performed. It remains to be determined whether the patients' overall survival and disease-free survival rates are correlated with genetic alteration of MET.

Biodegradation of polyurethane foam, revisited, in the rat model.

In a prospective, randomized, controlled animal study, we systematically analyzed implanted polyurethane foam to determine the rate of degradation in the rat and to compare it to our previous human data. Sixteen 1-cm2 silicone-backed pieces of polyurethane foam were randomly implanted into dorsal subcutaneous pockets in each of 16 Sprague-Dawley rats. Eight animals had polyurethane implants removed at 3 and 6 months and the remaining 8 animals at 9 and 12 months. Specimens were examined either by histology or by scanning electron microscopy of recovered foam after collagenase digestion of the capsule. Histologically, there was evidence of foam degradation and a multinucleated giant cell inflammatory response surrounding the implants. With the scanning electron microscope, the strut width of the polyurethane foam upon implantation measured 51.4 +/- 1.3 microns (mean+SEM). This progressively decreased to 29.1 +/- 1.3 microns at 3 months, 16.6 +/- 0.6 micron at 6 months, 14.9 +/- 0.5 micron at 9 months, and 13.2 +/- 0.3 micron at 12 months (p < 0.0001). Duration of implantation has a significant impact on polyurethane degradation as measured by scanning electron microscopy in the rat animal model. The rate of degradation in the rat is much faster than in our human study, indicating that the rat studies cannot be used to draw conclusions regarding rate of biodegradation in humans.

Global flap ischemia: a comparison of arterial versus venous etiology.

It has been suggested by clinical observations that acute venous thrombosis following free-flap surgery results in more severe tissue injury than postoperative arterial thrombosis. This current study, in the pig model, was designed (1) to determine the rate of survival and the percentage area of flap survival in both cutaneous and myocutaneous flaps following a secondary venous ischemic insult, (2) to compare this with findings following a secondary arterial ischemic insult, and (3) to determine the reliability of laser Doppler flowmetry and dermofluorometry index in the prediction of necrosis outcome following both venous and arterial ischemic insults. A total of 116 flaps were elevated in 29 pigs. Data analysis documented a decrease in the rate of flaps surviving venous ischemia as compared with arterial ischemia or control and of arterial ischemia as compared with control. In contrast to our previous work, a lower rate of buttock flaps survived a secondary ischemic insult (of either arterial or venous etiology) than did the cutaneous component of the myocutaneous flaps. As expected, as the length of ischemia increased, the rate of flaps surviving decreased, as did the percentage area of survival. Although laser Doppler performed slightly better than dermofluorometry index, as measured on immediate reperfusion following secondary venous ischemia, both were relatively poor predictors of eventual survival or necrosis. Under conditions of immediate reperfusion following secondary arterial ischemia, dermofluorometry index proved to be a superior predictor of ultimate necrosis as compared with laser Doppler flowmetry.

Canadian laparoscopic surgery survey.

OBJECTIVE: To assess the status of laparoscopic general surgery in Canada and the training experience and educational needs of Canadian surgeons, particularly with laparoscopic cholecystectomy (LC). DESIGN: All of Canada's practising general surgeons were surveyed by mail approximately 15 months after the general availability of laparoscopic video equipment. Questionnaires completed by 736 surgeons form the basis of the analysis. SETTING: The respondent profile produced a good sample distribution to assess differences related to age, experience, location and type of practice; 30% practised in communities of 50,000 or less; 38% in hospitals with 250 or fewer beds and 57% in community hospitals. RESULTS: Eighty-four percent had already learned LC, and 51% of them had performed more than 25 LCs. The number performed correlated directly with the number of cholecystectomies usually performed yearly before laparoscopy. Age and lack of relevance to practice were reasons for not learning. Ninety-one percent took formal training courses, usually university sponsored and in Canada. Complications were experienced by 44% of respondents. Bile leak (26%), hemorrhage (15%) and bile-duct injury (9%) were the most common and increased as the number of cholecystectomies usually performed prior to LC increased. Age, sex, type and location of hospital and size of city were not significant factors. The data show a consistent (p < 0.001) increase in the proportion of surgeons who encountered a complication as the number of LCs performed increased. CONCLUSIONS: LC has been introduced in Canada in an unpredicted, rapid and seemingly orderly and responsible fashion in all areas, types and sizes of communities. It has been equally well applied by surgeons of all ages and size of practice whether practising in the smaller community or in the university centre. The dogma of complications related to a "learning curve" is not supported by the author's data, and experience with complications is not restricted to the occasional biliary surgeon. Continued vigilance is necessary.

Prognostic significance of proliferating cell nuclear antigen expression in colorectal cancer.

BACKGROUND: Recognition of a biologic marker in colorectal cancer tissue that correlates with recurrence and poor survival would offer a rationale for planning aggressive adjuvant therapy. This study assessed the prognostic significance of proliferation activity in cancer cells and nonneoplastic epithelial cells in patients with colorectal cancer, using proliferating cell nuclear antigen (PCNA) immunohistochemical analysis. METHODS: A mouse monoclonal antibody that reacted with PCNA was used to measure proliferation indexes in neoplastic and nonneoplastic colonic tissues of two sex-matched and age-matched groups of 40 patients with different clinical outcomes. In one group of 20 patients, there was no evidence of recurrence or residual disease after a median follow-up of 5.3 years. In the other group, all 20 patients had died within 3.6 years of recurrent disease. RESULTS: The proliferation indexes in both cancer cells and epithelial cells of adjacent nonneoplastic crypts were elevated significantly in those who died compared with survivors; this finding was independent of other variables. There was evidence of an upward shift in the proliferation compartment of the normal crypt that occurred to the same extent in both patient groups. No correlation between Dukes stage and any of the proliferation indexes was observed. CONCLUSION: Proliferation indexes in neoplastic and adjacent normal mucosa, as defined by PCNA immunohistochemical analysis, are independent predictors of recurrence and poor survival in patients with colorectal cancer, indicating that they may be helpful as predictors of long-term survival and in planning prophylactic adjuvant therapy.

Results of the surgical treatment of obesity.

A prospective, randomized trial comparing vertical banded gastroplasty (VBG) and vertical gastric bypass (GB) for obesity was completed in 106 patients who did not differ in baseline body mass index (BMI = kg/m2) or length of follow-up. The goal of this surgery was to return patients to within 50% of their ideal weight, i.e., a body mass index less than 35 kg/m2, and to accomplish this while maintaining a low risk for malnutrition as well as other morbidity and mortality. Success was defined as a BMI less than 35 kg/m2 because the mortality risk increases rapidly above this degree of obesity. Surgical failures were encountered in 43% of the 54 patients in the VBG group, all of whom had division between the vertical staple lines. The main causes of failure were stenosis and enlargement of the gastroplasty orifice. Surgery failed in 23% of the GB-treated patients, due to perforation of the vertical staple line. An isolated gastric bypass (IGB) not dependent on staples was performed as the remedial operation for the failures of both VBG and GB. IGB was significantly better than VBG or GB, with a success rate of 83% compared with 39% for VBG and 58% for GB. Subsequent experience since completion of this randomized trial in 54 consecutive patients supports IGB for primary, as well as remedial, operations for the morbidly obese (BMI = 40 to 50 kg/m2), as well as for patients who are super obese (BMI greater than 50 kg/m2).

Coronary artery bypass using internal mammary artery branches.

The excellent long-term patency rates achieved with use of the internal mammary artery (IMA) to bypass the left anterior descending coronary artery have stimulated a variety of approaches to expand the use of this conduit in coronary bypass surgery. In this report we document our results using the two terminal branches of the IMA to bypass two arteries in a Y configuration. Sixty-seven patients received IMA Y grafts during a 6-month period in 1987. A total of 150 IMA branch anastomoses were performed (8 patients received bilateral IMA Y grafts). Fourteen of 67 patients were revascularized using IMA grafts only. Operative mortality was 2 of 67 (3%), and follow-up mortality was 5 of 67 (7.5%). Fifty-eight patients could be evaluated 37 +/- 2.7 months later. Clinically 36% of patients reported some recurrence of angina and 12 of 47 (25%) had a positive electrocardiographic stress test. Four patients were reoperated on (2 redo coronary artery bypass grafting, 2 transplants). Sixty (40%) of the 150 branch anastomoses could be evaluated objectively and 30 (50%) were patent. Five (8.5%) were stenotic and 25 (41.5%) were occluded (overall patency rate, 58.5%). We conclude that although the use of IMA Y grafts is a technically feasible means to increase IMA usage, extended application of this technique cannot be recommended unless improved patency rates can be demonstrated.

Coronary artery bypass profile in Canada and the United States.

This study compares computer registry data on coronary bypass surgery from several centres in Canada and the United States to assess current trends in patient profile, and looks at demand and resources available for this form of treatment. A computerized registry established at the Royal Victoria Hospital in 1982 was used to document the profile of patients undergoing coronary artery bypass graft. Comparing 1988 to the previous six years (1982-87), a significant increase was found in patients with unstable angina (P less than 0.001) and abnormal left ventricular function (P less than 0.015) among those operated. The incidence of emergency operations also increased (P less than 0.001). The patient profile was similar to that of the Toronto university hospital population and many major United States university hospitals. The incidence of coronary artery bypass graft per 100,000 population, however, is much greater in the United States than in Canada (120 versus 56). Resources in many Canadian centres appear to be insufficient to meet demand for this type of surgical intervention.

Links between passive smoking and disease: a best-evidence synthesis. A report of the Working Group on Passive Smoking.

We reviewed the toxicologic, clinical, and epidemiologic evidence on the health effects of environmental tobacco smoke (ETS). For each type of exposure to environmental tobacco smoke we have sought articles in the English language reporting studies of effects on human health. Formal criteria that stressed study design, quality of execution and generalizability of results were used to select 116 scientifically admissible reports from over 2,900 articles. We concluded that: (a) there is strong evidence of an association between residential exposure to environmental tobacco smoke and both respiratory illness and reduction of lung function, and also between maternal smoking and reduced birth weight; (b) the weight of evidence is compatible with an association between active maternal smoking during pregnancy and increased infant mortality, and also between residential exposure to environmental tobacco smoke (primarily spousal smoking) and the risk of lung cancer; (c) there is evidence consistent with a relationship between exposure to environmental tobacco smoke in the workplace and respiratory symptoms, (d) the evidence is insufficient to implicate residential exposure to environmental tobacco smoke in relation to other forms of malignant disease or congenital malformations; (e) there is no evidence in the literature of an association between nonresidential exposure to environmental tobacco smoke and any form of cancer. Further studies are required to address the effects of exposure to environmental tobacco smoke, especially nonresidential exposure, in carcinogenesis and as a risk factor for atherosclerosis. Further work is also needed to improve measurement of exposure in such studies and to assess the importance of confounding factors.