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Biomedical subjects

W Henderson

Publications and source records attributed to W Henderson.

At least 73 records · Page 4Linked to original sources
PubMed1989

Preoperative identification of patients likely to have left ventricular dysfunction after aortic valve replacement. Participants in the Veterans Administration Cooperative Study on Valvular Heart Disease.

The purpose of this study was to identify preoperative and intraoperative variables predictive of left ventricular dysfunction 6 months after aortic valve replacement. Patients were considered to have postoperative left ventricular dysfunction if the end-diastolic-volume index was greater than or equal to 101 ml/m2 or if the ejection fraction was less than or equal to 0.50. Data from 180 patients entered into the Veterans Administration Cooperative Study on Valvular Heart Disease who had technically satisfactory cardiac catheterizations 6 months postoperatively were analyzed by a series of univariate and multivariate analyses. For the 88 patients with preoperative aortic stenosis, the most powerful predictor of postoperative left ventricular dysfunction in the final multivariate model was preoperative left ventricular ejection fraction (p = 0.0001), followed by preoperative myocardial infarction (p = 0.012), aortic valve gradient (p = 0.020), and incomplete coronary revascularization (p = 0.059). Abnormal preoperative left ventricular ejection fraction had a sensitivity of 72% and a specificity of 82% in identifying patients with postoperative left ventricular dysfunction. Preoperative left ventricular systolic-volume index greater than or equal to 40 ml/m2 had a similar sensitivity and specificity (79% and 84%, respectively). For the 36 patients with aortic regurgitation, preoperative left ventricular ejection fraction was again the most powerful predictor of postoperative left ventricular dysfunction (p = 0.013), followed by left ventricular systolic pressure (p = 0.038) and arteriovenous oxygen difference (p = 0.054). For the 56 patients with mixed aortic stenosis and regurgitation, left ventricular systolic pressure (p = 0.007) and preoperative myocardial infarction (p = 0.022) were the variables predictive of postoperative left ventricular dysfunction. Although many patients with preoperative left ventricular dysfunction experience improved left ventricular performance after aortic valve replacement, performance does not always return to normal. For patients with either aortic stenosis or regurgitation, the strongest predictor of postoperative left ventricular dysfunction is preoperative dysfunction. These data support the concept that patients with moderate or severe aortic stenosis or regurgitation should be operated on before the onset of significant left ventricular dysfunction.

Aortic Valve↗
PubMed1988

Improvement in early saphenous vein graft patency after coronary artery bypass surgery with antiplatelet therapy: results of a Veterans Administration Cooperative Study.

To determine whether specific antiplatelet therapies improved vein graft patency after coronary artery bypass grafting (CABG) we compared (1) aspirin, 325 mg daily, (2) aspirin, 325 mg three times daily, (3) aspirin plus dipyridamole (325 mg and 75 mg, respectively, three times daily), (4) sulfinpyrazone (267 mg three times daily), and (5) placebo (three times daily). Therapy, except aspirin, was started 48 hr before CABG. When aspirin was a treatment, one 325 mg dose was given 12 hr before surgery and therapy was maintained thereafter according to the assigned regimen. Angiographic graft patency data were obtained within 60 days of surgery. Analysis of early graft patency in 555 patients (1781 grafts), revealed the following graft patency rates: aspirin daily, 93.5%; aspirin three times daily, 92.3%; aspirin and dipyridamole, 91.9%; and sulfinpyrazone, 90.2%. All aspirin-containing therapeutic regimens improved (p less than .05) graft patency compared with placebo (85.2%). Chest tube drainage measured within the first 35 hr after CABG revealed that the median loss with aspirin daily (965 ml), aspirin three times daily (1175 ml), and aspirin plus dipyridamole (1000 ml) exceeded (p less than .02) that with placebo (805 ml), while median loss with sulfinpyrazone (775 ml) did not. The reoperation rate was greater (p less than .01) in all the treatment groups that received aspirin (6.5%) compared with the two nonaspirin groups (1.7%). Overall operative mortality was 2.3%, without significant differences among treatment groups. Transient renal insufficiency occurred in 5.3% of patients taking sulfinpyrazone. Thus, early vein graft patency was improved after CABG with all aspirin-containing drug regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗
PubMed1987

The Vietnam Era Twin (VET) Registry: method of construction.

A Vietnam Era (1964-1975) Twin Registry of American male-male veterans born between 1939 and 1955 has been developed to provide a study sample for research evaluating the impact of Vietnam service on the medical and psychosocial aspects of health. In preparation for developing the Registry, several alternative sources of twins and methods for identifying twins were investigated. A computerized database of veterans discharged from the military after 1967 was selected as the source because it contains about 50% of the total Vietnam era veteran population, is reasonably unbiased, and provides a feasible method for identifying twins. Twins were identified using an algorithm which involved matching entries on the database for same last name, different first name, same date of birth, and similar social security number. Twin status was confirmed by review of military records. The registry, now complete, is composed of 7,400 twin pairs. It will be an important resource for future research projects.

Adult↗
PubMed1987

The Vietnam Era Twin (VET) Registry: ascertainment bias.

An examination of ascertainment bias in identification of twin pairs in the Vietnam Era Twin Registry has been conducted. A complete listing of all male-male Vietnam era veteran twin pairs born in Connecticut between 1939 and 1955 was obtained (N = 150). An attempt was made to match these pairs with a listing of Vietnam era veteran twin pairs derived from the United States Department of Defense's Defense Manpower Data Center (DMDC) computer files. The results indicate that the DMDC files identified only 46.7% of the 150 Connecticut born Vietnam era veteran pairs. Statistically significant differences (P less than 0.05) between pairs found on the DMDC files and Connecticut veteran pairs missing from the DMDC files are observed for the following variables: a) year of discharge from military service, b) total length of active military service, c) branch of service, and d) foreign service. No consistent pattern of bias is observed for factors related to the physical and psychosocial health of veteran pairs. The implications of the ascertainment biases in the Vietnam Era Twin Registry are discussed.

Adult↗
PubMed1987

Dietary patterns and metabolic control in diabetic diets: a prospective study of 51 outpatient men on unmeasured and exchange diets.

In a prospective, single blind study, 51 adult diabetic, male outpatients at or below ideal body weight (IBW), all but four of whom were insulin-treated, were randomly assigned to a calorically defined exchange diet (EXCH) or an unmeasured diet avoiding refined sugars (UNMEAS). Fasting chemistries, weights and 48-hr dietary recalls were obtained every 3 months for 3 years. There was no difference between groups in mean body weight, mean caloric intake, percentages of carbohydrate or fat intake, day to day consistency of caloric intake, or fasting chemistries. The patients whose actual weight tended to be less than IBW consumed more calories than their theoretical calculated needs (p = 0.002) without effect on glycemic control or stability of weight. Patients with low carbohydrate intake (less than 30%) had significantly higher triglyceride levels (p = 0.015). Otherwise, variations in dietary patterns were not reflected in fasting clinical chemistries. Individual fasting serum glucose levels were not related to consistency of carbohydrate intake, caloric distribution throughout the day or composition of diets. These results suggest that actual dietary patterns of subjects following exchange diabetic diets with precise caloric prescriptions are similar to those resulting from unmeasured diets with restriction of simple sugars. Other than correlation between carbohydrate intake and triglycerides, there was no detectable effect of variations in dietary patterns upon conventional chemical metabolic levels.

Adult↗
PubMed1977

Factors affecting performance during an endurance relay.

A successful attempt by Edinburgh Athletic Club on the world record for the 24-hour 10-man x 1 mile relay is reported. The effects of a variety of factors on the performances of the athletes are assessed, and some physiological changes noted. In the light of these observations recommendations are made to help the planning of future record attempts.

Heart Rate↗
PubMed1975

Inflammatory lesions localized with technetium Tc 99m-labeled leukocytes.

Canine leukocytes were labeled with a gamma-ray emitting isotope by permitting them to phagocytize technetium Tc 99m sulfur colloid particles in vitro and removing the unphagocytized particles by washing the cells. The labeled cells were reinfused intravenously into the donor dogs. Scintigraphic scans were performed 4 and 24 hours following the leukocyte infusion. In animals with sterile and infected intramuscular abscesses and pulmonary infections, it was possible to localize the lesions by scintigraphic scanning four hours following administration of labeled leukocytes. In one experiment, a positive scan was observed 24 hours after the leukocyte infusion. It was also shown that labeled leukocytes tend to concentrate in abscess fluid. These results suggest that technetium Tc 99m sulfur colloid-labeled leukocytes may be a useful diagnostic tool in localizing abscesses and inflammatory lesions in humans.

Abscess↗