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Biomedical subjects

B S Lewis

Publications and source records attributed to B S Lewis.

At least 73 records · Page 4Linked to original sources
PubMed1994

Doppler diastolic transmitral flow patterns in severe heart failure: response to controlled changes in filling pressure using intravenous isosorbide dinitrate.

Serial Doppler diastolic transmitral flow patterns were compared with simultaneous hemodynamic measurements in a homogeneous group of patients with severe (New York Heart Association class 4) heart failure who were receiving high dose (508 +/- 271 micrograms/min) intravenous isosorbide dinitrate. The Doppler tracing uniformly showed a severe restrictive pattern, with tall peak early diastolic filling (E) wave (84 +/- 12 cm/s), small late filling (A) wave (28 +/- 8 cm/s) and very high E/A ratio (3.2 +/- 0.8). Isosorbide dinitrate decreased wedge pressure and systemic vascular resistance by a third and increased cardiac index by more than 40%. Transmitral Doppler E/A ratio changed directly in relation to the changes in pulmonary capillary wedge (r = 0.85, p = 0.03) and right atrial pressure (r = 0.84, p = 0.03), indicating preload dependence of transmitral flow velocity, even in severe heart failure.

Aged↗
PubMed1994

Push and sonde enteroscopy for the diagnosis of obscure gastrointestinal bleeding.

OBJECTIVE: The combination of push and sonde enteroscopy permits endoscopic evaluation to extend the distal small bowel. Our objective was to determine the yields of both push and sonde enteroscopy in patients with obscure GI bleeding. METHODS: We retrospectively reviewed 553 small bowel examinations performed with an orally passed 135-cm pediatric colonoscope in combination with a 2750-cm per nasal sonde enteroscope to investigate the small bowel for sources of gastrointestinal bleeding of obscure origin. RESULTS: The examination reached the distal jejunum or beyond in over 90% of patients undergoing both push and sonde enteroscopy. The yield of these combined studies was 58% for identifying a possible source of gastrointestinal blood loss. In 40% of the examinations, the abnormality was found distal to the limits of routine upper gastrointestinal endoscopy. In 26% of all examinations, the lesion was detectable only by sonde enteroscopy. The most common small bowel findings were mucosal vascular lesions (31% of all exams) and tumors (6%). No major endoscopic complications occurred, and patients tolerated the procedures well. CONCLUSIONS: The combination of push and sonde enteroscopy is a valuable tool in the evaluation of obscure gastrointestinal bleeding and may provide useful information necessary to formulate treatment plans aimed at cessation of bleeding.

Adolescent↗
PubMed1994

Small intestinal bleeding.

Bleeding from the small intestine may be difficult to diagnose, because of the organ's length and free intraperitoneal location. Although there is a variety of causes of intestinal bleeding, angiodysplasia is the most common. Several different tests can be used to identify the bleeding site preoperatively or intraoperatively, including enteroscopy.

Aged↗
PubMed1993

Left ventricular systolic and diastolic function, and exercise capacity six to eight weeks after acute myocardial infarction. The DEFIANT Study Group. Doppler Flow and Echocardiography in Functional Cardiac Insufficiency: Assessment of Nisoldipine Therapy.

Echocardiographic and Doppler-derived measurements of left ventricular (LV) function at rest were examined as predictors of maximal bicycle exercise capacity in a homogeneous group of 115 patients with mild to moderate LV dysfunction (ejection fraction 22 to 56%, median 43%) participating in the DEFIANT study of nisoldipine after acute myocardial infarction. Although the relations were not exact, peak exercise work load 7 weeks after infarction correlated with measurements of diastolic LV function at rest. Exercise work load was inversely related to peak late diastolic transmitral blood flow velocity (A wave) (slope -86.6; 95% confidence interval -120.9 to -52.2) and directly to the E/A ratio (slope 20.5; 95% confidence interval 6.0 to 35.1). The relations between exercise work load and peak late diastolic flow velocity remained significant after correction for age, sex, heart rate at rest, and use of beta-blocking drugs or nisoldipine. There was no relation between peak exercise work load and peak early diastolic transmitral flow velocity (E wave), isovolumic relaxation period or deceleration time. Measurements of systolic LV function (LV end-diastolic and end-systolic volumes, and ejection fraction, stroke volume and cardiac index) were also not significant as predictors of exercise capacity.

Adult↗
PubMed1993

The effect of physician advice on exercise behavior.

BACKGROUND: Although sedentariness, a prevalent lifestyle, is recognized as a significant risk factor for coronary artery disease and other conditions, little is known about the effectiveness of prevention strategies in the primary care setting. This study examines the impact of brief, exercise advice-giving by family physicians. METHODS: During a 2-month baseline period, patients visiting their family physician and who were age 18 or older were queried about their exercise habits and attitudes and whether their physician had discussed exercise. During the following 2-month experimental phase, the same data were gathered, and half the physicians were trained to give brief exercise advice. All patients were followed for 1 month. Changes in exercise duration and frequency were the primary outcome measures. RESULTS: During baseline, a sizable portion of patients were given exercise advice. This was true also of control group patients during the experimental phase, although trained physicians gave advice almost twice as often. A comparison of the patients receiving advice with those not receiving advice revealed significant increases in exercise duration, but not frequency. Patient attitudes were responsive to exercise advice. CONCLUSION: Members of primary care, adult patient population will increase their duration of physical activity in response to physician advice to exercise.

Adult↗
PubMed1993

Haemodynamic and neurohumoral effects of flosequinan in severe heart failure: similarities and differences compared with intravenous nitroglycerin therapy.

The acute haemodynamic and neurohumoral effects of flosequinan, a new direct-acting vasodilator, were studied in 12 patients with severe (eight in New York Heart Association grade 3, four in grade 4) cardiac failure. Flosequinan was administered in a single oral dose of 100 mg, with haemodynamic monitoring over a 22 h period. The effects were compared with those observed during high dose intravenous nitroglycerin therapy (276 +/- 100 micrograms.min-1), given to the same patients for an identical period on the previous day. Both flosequinan and nitroglycerin produced significant haemodynamic improvement during the 22 h monitoring period. Cardiac and stroke indices increased with both drugs. However, while systemic and pulmonary vascular resistance were reduced similarly by both drugs, the decrease in right atrial and pulmonary capillary wedge pressures was greater with nitroglycerin and less with flosequinan, indicating a greater venodilator effect for nitroglycerin and a more balanced arterial and venodilator effect for flosequinan. Systemic arterial pressure and heart rate tended to increase with flosequinan and to decrease with nitroglycerin. In contrast to nitroglycerin, flosequinan did not increase plasma renin activity and serum aldosterone levels. Atrial natriuretic peptide decreased appropriately after both drugs, in keeping with the decreases in left and right heart filling pressures. The favourable haemodynamic and neurohumoral profiles of flosequinan suggest that it may be a useful vasodilating drug in the management of patients with severe heart failure.

Administration, Oral↗
PubMed1992

Atrial natriuretic peptide in severe heart failure: response to controlled changes in atrial pressures during intravenous nitroglycerin therapy.

Atrial natriuretic peptide (ANP) levels were measured in 17 patients with severe congestive heart failure (New York Heart Association functional class IV), and the response of the peptide was studied during changes in cardiac filling pressures induced by a 24-hour infusion of nitroglycerin. In the control state plasma ANP levels (687 +/- 551 pg/ml) were 10-fold normal. During the administration of nitroglycerin, natriuretic peptide levels decreased (p less than 0.005) with changes matching very closely the decreases in pulmonary arterial wedge and right atrial pressures, a 1% mean decrease in the peptide level for every 1.5 to 2% mean change in atrial filling pressures. In patients with hemodynamic tolerance to constant-dose nitroglycerin infusion, the resulting increase in atrial pressures was accompanied by an appropriate secondary increase in the plasma ANP level. During the 24-hour study period there was a direct linear relationship between both wedge (r = 0.93, p = 0.007) and right atrial (r = 0.93, p = 0.008) pressures and the plasma ANP level, with a zero-pressure ANP intercept near normal (69 pg/ml for wedge, 174 pg/ml for right atrial pressure). The findings were no different in a subgroup of five patients receiving simultaneous treatment with captopril, except that plasma renin activity was higher and the aldosterone level lower than in the control group by a factor of approximately 2.5. The close relationship and tracking of atrial pressure and natriuretic peptide curves suggested that the sensitivity of the atrial stretch response to changes in atrial filling pressures was maintained in severe congestive heart failure.

Aged↗
PubMed1992

Surgical approach to occult gastrointestinal bleeding.

In 5% of patients with gastrointestinal bleeding, standard evaluation fails to reveal the source of the bleeding. We describe the management of 71 patients treated for obscure gastrointestinal bleeding at the Mount Sinai Medical Center, New York, New York, from 1985 to 1991. There were 38 men (54%) and 33 women (46%). The mean age was 60 years. The patients had bleeding episodes for a mean period of 26 months and required an average of 20 units of blood prior to surgical treatment. All had undergone an extensive diagnostic workup including barium contrast studies, endoscopies, and angiographies. Some had multiple bleeding scans, Meckel scans, and surgical explorations. Three patients were found to have "watermelon stomach" on endoscopy and had an antrectomy. Sixty-eight (96%) patients underwent a preoperative small bowel enteroscopy, which revealed the precise diagnosis in 50 (70%) of the patients. All patients underwent surgery. In 30 (42%) patients in whom the bleeding site was not apparent at exploration, intraoperative enteroscopy was performed. Two actively bleeding patients had intraoperative enteroscopy, which failed to localize the bleeding site, and intraoperative scintigraphy was utilized. The bleeding was found to originate in small bowel arteriovenous malformation (AVM) (28 patients), leiomyoma (8 patients), primary small bowel malignancies (11 patients), and other causes (24 patients). Fifty-six patients (80%) had no further bleeding; 9 with multiple small bowel AVM have experienced rebleeding and are alive. Six patients died of recurrent bleeding, and six died of metastatic cancer. An aggressive approach should be applied in patients in whom standard evaluation fails to localize the source of gastrointestinal bleeding. Enteroscopy, surgical exploration with additional intraoperative enteroscopy, and occasional intraoperative scintigraphy can achieve an excellent yield and allow resection and potential cure.

Algorithms↗
PubMed1992

Systemic diseases affecting the mesenteric circulation.

The mesenteric circulation is acutely sensitive to processes that affect the entire body. Such systemic diseases and syndromes are reviewed with particular emphasis on the mechanisms by which they influence the mesenteric vasculature and blood flow.

Connective Tissue Diseases↗
PubMed1992

Usefulness of intracoronary isosorbide dinitrate in alleviating myocardial ischaemia during coronary balloon angioplasty.

The effect of intracoronary isosorbide dinitrate on provoked myocardial ischaemia during percutaneous transluminal coronary angioplasty (PTCA) was studied in 60 patients who had at least 1 mm electrocardiographic (ECG) ST segment deviation during a 70 s control balloon inflation period. Isosorbide dinitrate (dose 1 mg, 2 mg or 3 mg) or placebo (saline) was administered by slow intracoronary injection, and the ST segment changes recorded again during an identical dilatation period 2-4 min later. Following injection of isosorbide dinitrate, the severity of ST segment deviation decreased (1 mg -31 +/- 30%, P = 0.03; 2 mg -51 +/- 35%, P = 0.0001; 3 mg -36 +/- 32%, P = 0.002) during coronary balloon inflation, and the time until onset of 1 mm ST deviation was prolonged (1 mg +79 +/- 137%, P = 0.06; 2 mg +85 +/- 87%, P = 0.02; 3 mg +78 +/- 109%, P = 0.02). With the 3 mg dose, the time to maximum ECG change increased (+37 +/- 87%, P = 0.02). In the placebo group, there was a small decrease in the severity of ST segment deviation in patients receiving placebo (-23 +/- 32%, P = 0.03), but no change in the time to its onset or in the time to maximum ST deviation. Isosorbide dinitrate did not alter heart rate, systolic arterial pressure or the rate-pressure product at maximum ST segment change, implying that when isosorbide was administered by direct intracoronary injection, a direct cardiac effect was responsible for the major anti-ischaemic effect of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1992

Does hormonal therapy have any benefit for bleeding angiodysplasia?

Sixty-four patients took part in a cohort study measuring the efficacy of daily hormonal therapy in diminishing intestinal bleeding from small bowel angiodysplasia. Thirty patients received 5-10 mg norethynodrel either with mestranol, 0.075-0.15 mg (24 patients) or with conjugated estrogens, 0.625 mg (six patients). The cohort group consisted of 34 patients who either refused hormonal therapy (six patients) or were diagnosed early in our experience, before the resurgence of hormonal therapy (28 patients). Mean follow-up was 15.6 months (range 2-31 months) for the treated group and 13.4 months (range 1-23 months) for the untreated group. In addition, the change in monthly transfusion requirement with therapy was analyzed ("within group" analysis). Fifty percent (15 of 30) of the treated group required no further transfusion during therapy, while 44% (15 of 34) of the untreated group required no further therapy (not significant). During therapy, the mean monthly transfusion requirement of packed red blood cells in the treated group was not significantly different from that found before therapy (1.5 vs. 2.2 units, NS) or from that of the control group (1.5 vs. 1.6 units, NS). The findings do not support the use of hormonal therapy for bleeding from small intestinal angiodysplasia.

Adolescent↗
PubMed1992

Colonoscopy: a prospective report of complications.

Patients (N = 2,097) undergoing ambulatory office colonoscopy were followed to determine the incidence of endoscopic complications. In this group, 1,320 patients had diagnostic colonoscopy with or without biopsy; 777 patients had 2,019 polyps removed. Three of 2,097 patients (0.1%) had transient hypotension requiring i.v. fluid resuscitation and oxygen administration. All patients went home without sequelae. Acute postpolypectomy bleeding occurred in 11 of 777 patients (1%) requiring acute management; bleeding was controlled during colonoscopy in all. Postpolypectomy syndrome occurred in 9 of 777 patients (1%). All patients were treated medically. Late postpolypectomy bleeding occurred in 15 of 777 patients (2%). Perforation occurred in two of 777 patients (0.3%), at 1 and 9 days postpolypectomy. Both patients underwent surgery with uneventful recoveries. We conclude that office colonoscopy including polypectomy is safe. The overall complication rate for therapeutic ambulatory colonoscopy was 5%, with major events requiring hospitalization in 2% of patients.

Adolescent↗
PubMed1991

Small bowel tumours: yield of enteroscopy.

A total of 258 patients with obscure gastrointestinal bleeding were referred for small bowel enteroscopy, a procedure which allows endoscopic evaluation of most of the small intestine. A small bowel tumour was found in 5% of patients. In 50% of patients no diagnosis could be made, but when the cause of obscure bleeding was discovered small bowel tumours were the single most common lesion in patients younger than 50 years. Small bowel tumours causing gastrointestinal bleeding may remain undetected despite extensive diagnostic evaluation. We conclude that small bowel tumours are the most common cause of obscure gastrointestinal bleeding in patients less than 50 years of age. Small bowel enteroscopy is diagnostic of small bowel tumours even when all previous diagnostic studies, including enteroclysis and angiography, are negative.

Adult↗
PubMed1991

Effect of nisoldipine on exercise performance in heart failure following myocardial infarction.

The effects of the second generation calcium channel blocking drug nisoldipine on subjective and objective measurements of exercise performance were studied in 19 patients with moderate to severe heart failure (9 New York Heart Association functional class 2, 9 class 3 and 1 class 4) due to fixed ventricular dysfunction following myocardial infarction. Nisoldipine (10 mg 3 times daily) or placebo were administered for 8 weeks in a double-blind parallel study, assessing exercise performance by symptom-limited treadmill exercise testing using a modified Naughton protocol. Nisoldipine was well-tolerated and produced a small increase in peak estimated workload performed (6.2 +/- 2.9 to 8.2 +/- 3.0 METs, p = 0.06). The rate of perceived exertion (Borg scale) increased from 17.5 +/- 2.2 to 18.8 +/- 1.2 (p less than 0.02). The higher workload was performed at a lower peak systolic blood pressure (p = 0.03), higher peak heart rate (p = 0.06) and identical double product (NS). There was no change in resting and peak heart rate and blood pressure or in exercise performance in patients receiving placebo. Resting left ventricular ejection fraction, measured by radionuclide ventriculography, was unchanged after 8 weeks both in the placebo (21 +/- 9 to 20 +/- 9%) and nisoldipine (34 +/- 17 to 36 +/- 19%) groups.

Aged↗