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Biomedical subjects

R C Davidson

Publications and source records attributed to R C Davidson.

50 records · Page 3Linked to original sources

Presumptive tricuspid valve malfunction induced by a pacemaker lead: a case report and review of the literature.

A 23-year-old woman developed 3 degrees AV block with syncope. Insertion of a permanent pacemaker lead was followed by the onset of a persistent murmur in late systole preceded by single or multiple clicks. The murmur was best heard at the left sternal edge, grade 3-4/6 with two major frequencies (60-250 Hz), increased with inspiration and on assuming the erect posture. It was considered to be tricuspid in origin and related to interference of the tricuspid valve apparatus by the pacemaker lead resulting in tricuspid regurgitation. No tricuspid valve prolapse or flutter was seen on echocardiography. Withdrawal of the pacemaker lead resulted in immediate disappearance of the new auscultatory findings. Review of the literature suggests that the appearance of such a murmur following pacemaker insertion could be associated with later complications in relation to tricuspid valve dysfunction. It is therefore recommended that, under these circumstances, permanent pacemaker leads should be appropriately repositioned.

Adult↗

The future of home health agencies.

A multidisciplinary, multi-institutional, volunteer task force was convened by the Visiting Nurse Association (VNA) of Los Angeles to perform an evaluation of the agency and, on the basis of the evaluation, to make recommendations regarding the future potential of home health service agencies in the United States. For the VNA of Los Angeles, this use of a voluntary task force as a planning mechanism was successful; we strongly recommend its application to other agencies. The recommendations made were specific to the VNA of Los Angeles, but many are applicable to home health agencies in general. They called for an expansion of the types of services currently offered, with an emphasis on the coordinated team approach to health problems, an increased emphasis on preventive and health education services, and a movement toward providing services to groups as well as individual home care patients. The task force also urged willingness to expand services to include primary care. Modern management techniques were recommended as tools to increase the efficiency of home health service agencies. Potential new sources of revenue were proposed.

California↗

Brain-stem compression in rheumatoid arthritis.

A woman had cervical C-1 to C-2 subluxation with dysphagia. Initial improvement with halo cast and posterior fusion was followed by recurrence of symptoms, but transpharyngeal resection of the odontoid process had continued to alleviate symptoms at 18-month follow-up examination. The importance of vertical C-1 to C-2 subluxation in rheumatoid cervical arthritis is emphasized.

Arthritis, Rheumatoid↗

Prospective study of atherosclerotic disease progression in the renal artery.

BACKGROUND: The aim of this study was to determine the incidence of and the risk factors associated with progression of renal artery disease in individuals with atherosclerotic renal artery stenosis (ARAS). METHODS AND RESULTS: Subjects with >/=1 ARAS were monitored with serial renal artery duplex scans. A total of 295 kidneys in 170 patients were monitored for a mean of 33 months. Overall, the cumulative incidence of ARAS progression was 35% at 3 years and 51% at 5 years. The 3-year cumulative incidence of renal artery disease progression stratified by baseline disease classification was 18%, 28%, and 49% for renal arteries initially classified as normal, <60% stenosis, and >/=60% stenosis, respectively (P=0.03, log-rank test). There were only 9 renal artery occlusions during the study, all of which occurred in renal arteries having >/=60% stenosis at the examination before the detection of occlusion. A stepwise Cox proportional hazards model included 4 baseline factors that were significantly associated with the risk of renal artery disease progression during follow-up: systolic blood pressure >/=160 mm Hg (relative risk [RR]=2.1; 95% CI, 1.2 to 3.5), diabetes mellitus (RR=2.0; 95% CI, 1.2 to 3.3), and high-grade (>60% stenosis or occlusion) disease in either the ipsilateral (RR=1.9; 95% CI, 1.2 to 3.0) or contralateral (RR=1.7; 95% CI, 1.0 to 2.8) renal artery. CONCLUSIONS: Although renal artery disease progression is a frequent occurrence, progression to total renal artery occlusion is not. The risk of renal artery disease progression is highest among individuals with preexisting high-grade stenosis in either renal artery, elevated systolic blood pressure, and diabetes mellitus.

Aged↗

Clinical and duplex ultrasound follow-up after balloon angioplasty for atherosclerotic renal artery stenosis.

The purpose of this study was to investigate changes in blood pressure and renal function after percutaneous renal artery balloon angioplasty in hypertensive patients with atherosclerotic renal artery stenosis. Renal artery lesions were assessed by duplex ultrasound before and after renal artery balloon angioplasty. Renal arteries were classified as normal, < 60% stenosis, > or =60% stenosis, and occluded according to previously validated duplex criteria. Data regarding risk factors for atherosclerosis and years of hypertension were collected. Systolic and diastolic blood pressure, creatinine, and number of medications were obtained before and after intervention. The immediate technical outcome of renal artery angioplasty was classified based on the arteriographic result as follows: success (residual stenosis < or =30%), partial success (residual stenosis 31-50%), or unsuccessful (residual stenosis > 50%). For bilateral procedures, success required both renal arteries to be classified as technical successes; a technical success on one side only was classified as partial success. The blood pressure response to intervention was classified as follows: cure (diastolic blood pressure < or =95 mm Hg on no medications), improved (control of blood pressure with a significant reduction in number of medications or control of previously elevated blood pressure without a change in medications), or failed (all other responses). The study group included 28 patients (14 men, 14 women) with a mean age of 65 years. The preintervention and the first postintervention evaluations occurred within 180 days of the procedure. All patients were hypertensive, and all except one were under medical treatment. Mean duration of hypertension was 9.1 +/-8.8 years. There were 38 interventional procedures (28 unilateral, 10 bilateral) involving 41 renal arteries; seven arteries had two procedures done. Before angioplasty, all renal arteries had lesions of > or =60% diameter reduction by duplex scanning. Endovascular stents were deployed following angioplasty in 14 (34%) of the procedures. The technical result was classified as a success in 24 (63%), a partial success in 12 (32%) of the procedures, and two procedures (5%) were classed as technical failures. There were statistically significant reductions in blood pressure following successful and partially successful procedures, but cure of hypertension was achieved in only 11% of cases. There were no significant changes in creatinine in any of the technical result groups. Of the 38 renal arteries evaluated with duplex ultrasound following intervention, 39% were found to have stenosis of > or =0% involving a treated renal artery, including one postintervention occlusion. Cure of hypertension was rare in this patient population with atherosclerotic renal artery stenosis. More than one third of the treated renal arteries showed > or =0% lesions recurring after the procedure. Thirteen percent of those with technical success and 17% of those with partial technical success had creatinine improvement of at least 20% over the baseline value. Significant clinical and anatomic improvement were relatively uncommon following balloon angioplasty in this series of patients.

Aged↗

The "one-and-two" family practice residency revisited.

First brought to the attention of the medical education community in 1977, the "one-and-two" program was designed to improve the relevance of residency training by using both a university teaching hospital and a smaller community hospital as training centers. This paper reviews the progress of implementing this format over the past ten years, and cites some of the advantages and disadvantages encountered from doing so.

California↗