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Biomedical subjects

L Pettigrew

Publications and source records attributed to L Pettigrew.

4 recordsLinked to original sources
PubMed1996

Detection of microemboli by transcranial Doppler ultrasound.

Doppler ultrasound detection of abnormally high-pitched signals within the arterial waveform offers a new method for diagnosis, and potentially for prediction, of embolic complications in at-risk patients. The nature of Doppler "microembolic" signals is of particular interest in patients with prosthetic heart valves, where a high prevalence of these signals is observed. Monitoring the middle cerebral artery with 2-MHz transcranial Doppler ultrasound (TC-2000, Nicolet Biomedical; Warwick, UK), we looked for microemboli signals in 150 patients (95 women and 55 men), and found 1 or more signals during a 30-min recording in 89% of 70 patients with Bjork-Shiley valves (principally monostrut), 54% of 50 patients with Medtronic-Hall valves, and 50% of 30 patients with Carpentier-Edwards valves (p < 0.001, chi 2). In the patients with Bjork-Shiley valves, the mean number of signals per hour was 59 (range, 42-86; 95% confidence interval), which was significantly higher than the mean in patients with Medtronic-Hall and Carpentier-Edwards valves (1.5[range, 0.5-2.5] and 1 [range, 0-5.3], respectively; both p < 0.04, multiple comparisons. Bonferroni correction). In the patients undergoing serial pre- and postoperative studies, the causative role of the valve implant was emphasized. There was no correlation between the number of emboli signals and a prior history of neurologic deficit, cardiac rhythm, previous cardiac surgery, or the intensity of oral anticoagulation, in patients with prosthetic heart valves. In Bjork-Shiley patients, dual (mitral and aortic) valves were associated with more signals than were single valves. In Medtronic-Hall patients, the signal count was greater for valves in the aortic position than it was for valves in the mitral position. Comparative studies of Doppler emboli signals in other clinical settings suggest a difference in composition or size of the underlying maternal between prosthetic valve patients and patients with carotid stenosis. These studies also suggest that the signals are of gaseous origin in valve patients. The clinical significance of continuing microembolism remains to be determined.

Carotid Stenosis↗
PubMedDate not supplied

White matter medullary infarcts: acute subcortical infarction in the centrum ovale.

Acute infarction confined to the territory of the white matter medullary arteries is a poorly characterised acute stroke subtype. 22 patients with infarction confined to this vascular territory on CT and/or MRI were identified from a series of 1,800 consecutive admissions to our stroke unit (1.2%) between August 1993 and March 1997. 19 patients had small infarcts (< 1.5 cm maximum diameter) and 3 large infarcts (> 1.5 cm). Small infarcts were associated with a history of smoking (69%), hypertension (58%), and hyperlipidaemia (37%), and less frequently with atrial fibrillation (21%). Significant (>50%) ipsilateral carotid stenosis (16%) was a less frequent finding in this group. Patients most commonly presented with weakness and/or sensory disturbance affecting mainly the upper limbs, but dysarthria, dysphasia, and ataxia were also seen. Large infarcts were infrequent in our series, but did not differ significantly from small infarcts with respect to clinical presentation or risk factor profiles (p > 0.05 for all comparisons). The majority of symptomatic patients with white matter medullary infarcts are associated with small (< 1.5 cm diameter) lesions and a risk factor profile consistent with small vessel disease. More data are required to elucidate the mechanism of larger (> 1.5 cm) infarcts. Because of the potential overlap between white matter medullary infarcts and internal watershed infarcts, suggested criteria for each are presented.

Acute Disease↗
PubMedDate not supplied

Implementing a year-long, worksite-based incentive program for smoking cessation.

BACKGROUND: There have been few reports of the process of implementing ongoing worksite health promotion programs. This article describes the implementation of a year-long smoking cessation program in nine worksites employing a total of approximately 700 smokers. METHODS: Issues discussed include: forming a partnership with organizations, design of the multicomponent incentive intervention, program promotion, maintaining participation, and the need to modify program components over time. RESULTS: The program produced high participation rates (29% of smokers joined the program) and moderate cessation rates among participants (during the last half of the program, monthly cessation rates averaged 20%). There was marked variability across worksites on both participation and cessation, and qualitative features of organizations associated with outcome are discussed. DISCUSSION: The importance of working with employee steering committees to tailor health promotion programs to fit the organization is discussed. The article concludes with recommendations for implementation of similar programs.

Follow-Up Studies↗