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Richard M Royall

Publications and source records attributed to Richard M Royall.

4 recordsLinked to original sources
PubMed2003

Cognitive changes with coronary artery disease: a prospective study of coronary artery bypass graft patients and nonsurgical controls.

BACKGROUND: Cognitive impairment after coronary artery bypass grafting (CABG) is well recognized, but previous investigations have been limited by lack of an appropriate control group. We compared changes in cognitive performance at 3 and 12 months after CABG with those in a control group of patients with comparable risk factors for coronary artery disease (CAD) who had not undergone surgery. METHODS: Patients undergoing CABG (n = 140) and demographically similar nonsurgical control subjects with CAD (n = 92) completed baseline neuropsychological assessment and were followed prospectively at 3 and 12 months. Cognitive function was evaluated with a battery of neuropsychological tests assessing the cognitive domains of attention, language, verbal and visual memory, visuoconstruction, executive function, and psychomotor and motor speed. RESULTS: The CABG patients who were tested in their hospital rooms before surgery had lower scores for timed tests; however, after adjustment for demographic variables and testing location there were no statistically significant differences between the CABG and nonsurgical control subjects in baseline neuropsychological test performance. Both groups improved from baseline to 3 months; the only statistically significant group difference was a greater improvement in the CABG group with regard to verbal memory. At 12 months there were no statistically significant differences between the two groups. CONCLUSIONS: The prospective longitudinal neuropsychological performance of patients with CABG did not differ from that of comparable nonsurgical control subjects with CAD at 3 months or 1 year after base line examination. This suggests that the previously reported cognitive decline during the early postoperative period after CABG is transient and reversible. Continued follow-up will determine whether a specific "late decline" occurs in CABG patients but not in nonsurgical control subjects with similar risk factors for cardiovascular and cerebrovascular disease.

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PubMed2002

Electrical stimulation promotes motoneuron regeneration without increasing its speed or conditioning the neuron.

Motoneurons reinnervate the distal stump at variable rates after peripheral nerve transection and suture. In the rat femoral nerve model, reinnervation is already substantial 3 weeks after repair, but is not completed for an additional 7 weeks. However, this "staggered regeneration" can be temporally compressed by application of 20 Hz electrical stimulation to the nerve for 1 hr. The present experiments explore two possible mechanisms for this stimulation effect: (1) synchronization of distal stump reinnervation and (2) enhancement of regeneration speed. The first possibility was investigated by labeling all motoneurons that have crossed the repair at intervals from 4 d to 4 weeks after rat femoral nerve transection and suture. Although many axons did not cross until 3-4 weeks after routine repair, stimulation significantly increased the number crossing at 4 and 7 d, with only a few crossing after 2 weeks. Regeneration speed was studied by radioisotope labeling of transported proteins and by anterograde labeling of regenerating axons, and was not altered by stimulation. Attempts to condition the neuron by stimulating the femoral nerve 1 week before injury were also without effect. Electrical stimulation thus promotes the onset of motor axon regeneration without increasing its speed. This finding suggests a combined approach to improving the outcome of nerve repair, beginning with stimulation to recruit all motoneurons across the repair, followed by other treatments to speed and prolong axonal elongation.

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PubMed2002

Encephalopathy and stroke after coronary artery bypass grafting: incidence, consequences, and prediction.

BACKGROUND: In contrast to perioperative stroke, much less attention has been paid to those with evidence of diffuse brain encephalopathy, presenting as delirium, confusion, coma, and seizures in the immediate postoperative period. OBJECTIVE: To determine the incidence, consequences, and predictive factors for encephalopathy and stroke following coronary artery bypass grafting. METHODS: In a prospective evaluation of 2711 patients operated on between January 1, 1997, and December 31, 2000, preoperative risk factors were obtained before surgery and postoperative outcomes, encephalopathy and stroke, were determined on a daily basis. All strokes were confirmed by neurologic consultation and, in most instances, by imaging. Logistic regression analyses were performed to determine risk factors for these outcomes. RESULTS: The incidence of encephalopathy was 6.9% and of stroke, 2.7%. For patients without either of these outcomes, the average length of stay in the hospital was 6.6 days and the mortality was 1.4%. In contrast, patients with encephalopathy had a length of stay of 15.2 days and a mortality of 7.5%, and those with stroke, a length of stay of 17.5 days and a mortality of 22.0%. Predictive models were developed for encephalopathy involving 5 preoperative factors (age, past stroke, carotid bruit, hypertension, and diabetes) and 1 perioperative factor (time on cardiopulmonary bypass). The model for stroke involved only 3 preoperative risk factors (past stroke, hypertension, and diabetes). CONCLUSIONS: Encephalopathy or stroke is associated with significant increases in length of stay and mortality after coronary artery bypass grafting. Patients at higher risk for these outcomes can be identified before surgery.

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