Thesis (Ph.D.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 142-164). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:NR38999

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 253-284).

Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: oxygen consumption; PET; blood flow. Includes bibliographical references (p. 58-61).

published_or_final_version / Nursing Studies / Master / Master of Nursing

Background Management of coronary heart disease remains a challenge even with modern advances. New anti-platelet agents which reduce thromboembolic events in patients with coronary heart disease were introduced. However, there are concerns about an increased in bleeding risk for patients taking these new anti-platelet agents. Platelet function test, such as VerifyNow, claimed to be able to predict bleeding risk. However, the evidence was limited, especially among the Asian population. This study aimed to evaluate the use of VerifyNow to assess bleeding risk. Subjects with low residual platelet reactivity, i.e. low PRU value, were hypothesized to have an increased bleeding risk. Methods This was a case control study performed in the Princess Margaret Hospital of Hong Kong. A total of 120 subjects who were taking a P2Y12 inhibitor and had a VerifyNow test were recruited. The cases were defined as subjects with a PRU value of less than or equal to 95, a threshold for increased bleeding risk as recommended by Western studies. The controls were age matched to the cases. The primary outcome was the increase in bleeding risk associated with a low PRU value at 30 days. The secondary outcome was the increase in bleeding risk associated with a low PRU value at 1 year. The use of the percentage of platelet inhibition was also evaluated as a secondary outcome. Multivariable logistic regression was used to obtain the odds ratio of the low PRU group. Results Bleeding events occurred more frequently in the low PRU group. At 30 days, 31.7% of subjects among the case had a bleeding event while 43.3% of the cases had a bleeding event at 1 year. The majority of these bleeding events were minor bleeding, such as easy bruising. After adjusting for confounders, there was no statistically significant increase in bleeding risk among those in the low PRU group at 30 days or 1 year. Subjects with a high percentage of platelet inhibition (>50%) was also not associated with a statistically significant increase in bleeding risk. Conclusion A low PRU value was not associated with an increased bleeding risk at 30 days. Thus the VerifyNow test was not shown to be useful in assessing the bleeding risk of patients in an Asian population, contrary to the findings from Western literature. A possible explanation was that the VerifyNow threshold for predicting bleeding might be higher among the Asian population. The definition for low residual platelet reactivity might be different in our locality. A larger sample size might also be needed. Further studies are needed to evaluate whether a different cut off is more optimal for the Asian population. / published_or_final_version / Public Health / Master / Master of Public Health

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Purpose: The primary purpose of the study was to assess if physical activity (PA) habits change between the first and final week in a phase II cardiac rehabilitation (CR) population and to determine if the PA habits differ on CR days versus non-CR days. The secondary purpose of the study was to determine if there were differences between the two PA assessment methods. Methods: There were 41 male subjects and 16 female subjects that volunteered for the study; however only 25 male subjects (age: 64.7 ± 11.4 years, BMI: 28.8 ± 4.5 kg/m2) and 11 female subjects (age: 65.2 ± 13.3 years, BMI: 31.6 ± 4.0 kg/m2) were included in the data analyses after accounting for dropouts and subject's whose data did not meet validation criteria. Subjects were required to wear both of the activity devices (pedometer and accelerometer) during both the first and final week assessments. Steps/day, activity counts/day, inactive minutes/day, light minutes/day and walking minutes/day were assessed by the Actigraph Accelerometer. Results: There was no significant difference in step counts from 5,290 ± 1,561 steps/day during the first week assessment to 5,730 ± 1,447 steps/day during the final week assessment. However, significant differences were seen between rehabilitation and nonrehabilitation days step counts/day (6,503 ± 1,663 steps/day vs. 4,517 ± 1517 steps/day, respectively). Furthermore, there was a significant increase between the first and final weeks activity counts/day (144,185 ± 56,399 counts/day vs. 165,220 ± 51,892 counts/day respectively) and a significant increase between rehabilitation and non-rehabilitation days activity counts/day (175,692 ± 58,239 counts/day vs. 133,712 ± 46,139 counts/day respectively). Conclusions: The results of the study suggest that patients are performing significantly more activity on days they attend rehabilitation versus days they do not attend rehabilitation. Furthermore, activity counts/day increased between the first and final weeks of rehabilitation and were higher on CR days vs. non-CR days, which may be due to the progressive exercise prescription associated with Phase II CR. Therefore, it was concluded that Phase II CR successfully increases the intensity of PA on CR days and between the first and final week of CR.Key Words: Cardiac Rehabilitation, Coronary Artery Disease, Pedometer, Accelerometer. / School of Physical Education, Sport, and Exercise Science

Physical inactivity is a significant health concern for individuals in the United States, and is especially an issue for those with a history of coronary artery disease. Increased physical activity is encouraged for those who are participants in Phase III cardiac rehabilitation to promote a healthy lifestyle after a cardiac event. The purpose of the study was to assess and characterize the physical activity levels of Phase III cardiac patients. Other objectives of this study were to compare various forms of physical activity assessment and compare the activity levels of the cardiac rehabilitation participants with other populations. Comparisons of three physical activity devices were analyzed as well as activity levels on rehab and non-rehab days. Those who participated in home exercise vs. those who did not do home exercise were compared as well as those who were retired vs. those who were employed. Subject inclusion criteria included Phase III cardiac patients who were 40-69 years of age and who attended rehab a minimum of two days per week. The subjects were required to wear a pedometer and accelerometer for at least 12 days and complete a questionnaire following the trial. The mean ± S. D. for age, height, weight and BMI of the subjects was 59.4±8.2 years, 69.1±3.1 inches, 200.9±41.8 lbs., and 29.4±4.8 kg/m2 respectively. The Lifecorder, ActiGraph and International Physical Activity Questionnaire (IPAQ) were used to measure physical activity levels of the Phase III cardiac patients. The IPAQ did not correlate well with the Lifecorder or ActiGraph in assessing physical activity in Phase III cardiac patients (R=0.251, P=0.226-ActiGraph and R=0.280, P=0.175-Lifecorder), however, the Lifecorder and the ActiGraph had a significant correlation coefficient with one another (R=0.83, P<0.001). Rehab vs. non-rehab day data as well as rehab session and non-rehab session physical activity levels were compared among the subjects. On a rehab day, subjects took 9,770±3132 steps/day, which was significantly higher than what they took on a non-rehab day, 5,404±2843 steps/day. Those who did not exercise at home accumulated on average 8,194±2912 steps/day on a rehab day, while on a non-rehab day they accumulated 3,475±1579 steps/day (P<0.001). Those who did exercise at home, took 10,883±2856 steps/day on a rehab day, while on a non rehab day they took 6,767±2768 steps/day (P<0.001). Those who were employed were more active than those who were retired. In conclusion, Phase III cardiac rehabilitation is an effective way to increase physical activity levels of those with a history of coronary artery disease. All participants in Phase III cardiac rehabilitation should be encouraged to come into the center-based facility at least 4-5 days per week or implement a home exercise program into their weekly regimen. / School of Physical Education, Sport, and Exercise Science