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Biomedical subjects

S J Phillips

Publications and source records attributed to S J Phillips.

At least 19 recordsLinked to original sources
PubMed1992

Benefits of combined balloon pumping and percutaneous cardiopulmonary bypass.

Sixteen patients (2 women, 14 men) aged 29 to 72 years with continued cardiogenic shock during intraaortic balloon pumping (IABP) had additional treatment with percutaneous cardiopulmonary bypass (PBY). Cause of cardiogenic shock was myocardial infarction in 7 (3 survived), failed percutaneous transluminal coronary angioplasty requiring emergency coronary artery bypass grafting in 5, postoperative aortic valve replacement in 1, postoperative emergency coronary artery bypass grafting in 1, after cardiac transplantation in 1, and bridging to transplantation in 1. Mean blood pressure with PBY and IABP combined was 75 mm Hg versus 60 mm Hg with IABP off. Percutaneous cardiopulmonary bypass flows ranged from 0.8 to 2.1 L/min with a mean flow of 1.3 L/min. Time on IABP ranged from 24 hours to 1 week. Time on IABP to PBY ranged from 1 to 20 hours, and time on PBY ranged from 65 minutes to 20 hours. Ten of 16 (63%) were successfully weaned, and 3 died after weaning. Seven of 16 (44%) survive. Combined IABP with PBY appears to be a better therapy than either one individually. Staging the therapy as the balloon first in and last out appears to be a good methodology.

Adult↗
PubMed1992

Sheathless insertion of the percutaneous intraaortic balloon pump: an alternate method.

A technique is described that allows insertion of a standard percutaneous intraaortic balloon without use of the larger 12F sheath. Standard 9.5-cm. Percor balloons were inserted in a series of patients without using the provided sheath. Elimination of the sheath reduced the potential vascular complications related to the extra bulk placed in the femoral artery by the sheath. No serious complications were noted in more than 25 patients.

Humans↗
PubMed1992

Relationship of cardiac disease to stroke occurrence, recurrence, and mortality.

BACKGROUND AND PURPOSE: This is a study of cardiac diseases associated with the 1,382 cases of first cerebral infarction in residents of Rochester, Minn., during 1960-1984. METHODS: This is a population-based study in Rochester, Minn., for which the medical record-linkage system was used to identify cardiac disease among patients with first cerebral infarction. RESULTS: There were 318 patients (23%) who had at least one major potential cardiac source of emboli. The proportion of patients with a cardiac source of emboli was significantly higher among patients older than age 75 years (29%) than among younger patients (17%). The 30-day stroke recurrence rate among patients with a cardiac source of emboli (2%) was not significantly different than that among those without a cardiac source of emboli (2%). Among patients with a cardiac source of emboli, there was no difference in the probability of stroke at 30 days and at 90 days for those treated or not treated with anticoagulants. During the first 30 days after cerebral infarction, the risk of death in patients with a cardiac source of emboli (23%) was 14 times that of recurrent stroke. The risk of death at 30 days in patients without a cardiac source of emboli was 8%. CONCLUSIONS: Significant independent predictors of death (Cox proportional-hazards analysis) were age, prior myocardial infarction, atrial fibrillation present at onset of stroke, congestive heart failure before the stroke, and an age x congestive heart failure interaction. The only significant independent predictors of recurrent stroke were cardiac valve disease and congestive heart failure.

Cerebrovascular Disorders↗
PubMed1992

Hypertension and the brain. The National High Blood Pressure Education Program.

Neurogenic mechanisms are important in the maintenance of most forms of hypertension, yet the brain is highly vulnerable to the deleterious effects of elevated blood pressure. Hypertensive encephalopathy results from a sudden, sustained rise in blood pressure sufficient to exceed the upper limit of cerebral blood flow autoregulation. The cerebral circulation adapts to chronic less severe hypertension but at the expense of changes that predispose to stroke due to arterial occlusion or rupture. Stroke is a generic term for a clinical syndrome that includes focal infarction or hemorrhage in the brain, or subarachnoid hemorrhage. Atherothromboembolism and thrombotic occlusion of lipohyalinotic small-diameter end arteries are the principal causes of cerebral infarction. Microaneurysm rupture is the usual cause of hypertension-associated intracerebral hemorrhage. Rupture of aneurysms on the circle of Willis is the most common cause of nontraumatic subarachnoid hemorrhage. Stroke is a major cause of morbidity and mortality, particularly among persons aged 65 years or older. Treatment of diastolic hypertension reduces the incidence of stroke by about 40%. Treatment of isolated systolic hypertension in persons aged 60 years and older reduces the incidence of stroke by more than one third. Blood pressure management in the setting of acute stroke and the role of antihypertensive therapy in the prevention of multi-infarct dementia require further study.

Aged↗
PubMed1991

The architecture of adventitial elastin in the canine infrarenal aorta.

Although the artery wall consists of three distinct layers, only the structures of the intima and media have been well characterized. The adventitia has generally been overlooked. Our examination focused on the organization of elastin and collagen which are the major components of this tunic. Canine infrarenal aortas were excised, stretched to their in vivo length, then pressure fixed in formalin. Transverse, longitudinal, and frontal sections were prepared with specific elastin and collagen stains. Areas of adventitia in these sections were examined with LM, and interconnections between collagen and elastin were photographed at various magnifications. Subsequently, the slides were fractured for attachment to SEM stubs, and the coverslips were demounted. The identical areas were then examined with SEM using the LM micrographs as a guide to identify elastin and collagen. Whole mount aortic ring preparations were digested in formic acid for 72 and 96 h at 45 degrees C to confirm adventitial elastin architecture. The adventitia was organized in alternating lamellae of collagen and elastin. The elastin lamellae consisted of continuous sheets of elastin with a longitudinal fibrillar substructure. Finer circumferential elastin fibers were also identified. These attached to both longitudinal elastin and adjacent collagen lamellae. Collagen lamellae were arranged in broad corrugated bands of fibrils. The unique architecture of the adventitia may explain some of the visco-elastic properties of the aorta in both normal and pathologic states.

Animals↗
PubMed1991

Treatment of cardiogenic shock with the Hemopump left ventricular assist device.

A multiinstitutional study is in progress to evaluate the Hemopump in the treatment of cardiogenic shock. Fifty-three patients with refractory cardiogenic shock were selected for Hemopump assistance. The hemodynamic definition of cardiogenic shock included (1) a cardiac index of less than 2.0 L.min-1.m-2, (2) pulmonary capillary wedge pressure of greater than 18 mm Hg, and (3) a systolic blood pressure of less than 90 mm Hg or a left ventricular work index of less than 1,500 g-m.m-2.min-1. The Hemopump was successfully inserted in 41 of 53 patients (77.3%). A significant improvement in the hemodynamic status was seen during Hemopump assistance. A minimal level of hemolysis was observed. No leg ischemia was observed. The 30-day overall survival of the Hemopump group was 31.7%. Criteria establishing indications for use and clinical utility are proposed. We conclude that the Hemopump provides significant hemodynamic support of the patient in cardiogenic shock allowing for recovery from ventricular stunning in marginal ventricles, and that in select patients the Hemopump may offer a major improvement in survival over conventional therapy.

Cardiac Output↗
PubMed1991

Cutaneous effects of transdermal levonorgestrel.

The irritation of transdermal devices delivering levonorgestrel and the permeation enhancer ethyl acetate with or without ethanol was evaluated in rabbits. Erythema and oedema were assessed 24, 48 and 72 hr and 7 days after application of the 24-hr delivery system. The devices were found to be mild to moderately irritating, with erythema the primary manifestation. No differences were observed between devices using pure ethyl acetate or ethyl acetate-ethanol (7:3, v/v) as enhancers. Devices using pure ethanol as an enhancer gave levels of irritation similar to those using ethyl acetate-ethanol (7:3) or pure ethyl acetate. Control devices containing only water (no drug) were also found to be mildly irritating to rabbits following a 24-hr exposure period. A histological evaluation of the application sites of two of the formulations confirmed the visual observations of mild subacute irritation. The changes produced by transdermal levonorgestrel were reversible. The problems of skin irritation of transdermal devices is discussed with particular reference to the use of ethyl acetate and ethanol as skin penetration enhancers.

Acetates↗
PubMed1991

Epidemiological characteristics of lacunar infarcts in a population.

BACKGROUND AND PURPOSE: This study evaluated the characteristics and natural history of patients with lacunar (small, deep) cerebral infarcts in a defined population for comparison of these characteristics to those in patients with nonlacunar infarcts. METHODS: This is a population-based study in Rochester, Minnesota, from 1960 to 1984, that used the medical record-linkage system to identify and characterize patients with cerebral infarction. RESULTS: The age- and sex-adjusted average annual incidence rate of lacunar cerebral infarction was 13.4/100,000 persons, accounting for 12% of all first cerebral infarcts. Temporal trends in incidence rates, stroke recurrence rates, prevalence of diabetes mellitus, and causes of death (given survival for 30 days) for cases of lacunar infarction were not significantly different from those for cases of nonlacunar infarction. Hypertension was found in 81% of patients who had a lacunar infarct and in 70% of patients who had a nonlacunar infarct (p = 0.05). A potential cardiac source of embolism was found in 12% of patients who had a lacunar infarct and in 28% of patients who had a nonlacunar infarct (p = 0.002). Survival was significantly better after a lacunar infarct than after a nonlacunar infarct. CONCLUSIONS: Small, deep cerebral infarcts had many of the epidemiological characteristics of other cerebral infarcts but there was a slightly higher frequency of hypertension, significantly lower frequency of a cardiac embolic source, and significantly better survival in patients with lacunar infarction than in those with nonlacunar infarction.

Cerebral Infarction↗
PubMed1990

Carbon dioxide milliwatt laser in the vasovasostomy of vas deferens in dogs: Part I.

This is the first arm of a two prong study conducted to learn two different aspects of vasovasostomy in dog vas deferens using the milliwatt carbon dioxide laser. The first study involved the evaluation of patency without collection of sperm. Six dogs were evaluated and all underwent vasectomy and subsequently had vasovasostomies performed between 4 and 12 weeks utilizing two approximating sutures and welding with the milliwatt carbon dioxide laser. Metal clips were used for both X-ray analysis and localization of the vasovasostomy site. In this investigation a vasogram was performed. Dogs were sacrificed at 4, 6, and 8 weeks postvasovasostomy. The vasovasostomy specimens were studied with electron microscopy and histological evaluation. The vasovasostomy was completed in under 120 minutes using this laser-assisted technique and was found to be a viable and promising technique for vasovasostomy.

Animals↗
PubMed1990

Vasovasostomy in dogs using the carbon dioxide milliwatt laser: Part II.

This is the second study of a two-prong investigation conducted to learn two different aspects of vasovasostomy in dog vas deferens by using the carbon dioxide milliwatt laser. This investigation involves the evaluation of patency and analysis of sperm. Six dogs underwent vasectomy, followed by vasovasostomies performed between 4 and 12 weeks later, utilizing two approximating sutures and welding with the carbon dioxide milliwatt laser. Metal clips were used both for x-ray analysis and localization of the vasovasostomy site. All dogs had pre-vasectomy semen analysis. Following vasectomy each dog underwent ejaculation until azoospermia was obtained. Vasovasostomy was performed and semen was examined. Prior to harvesting, vasography was also obtained. All ejaculates had active sperm noted and 12 of 12 vasograms (100%) revealed patency. The dogs were sacrificed at 4 weeks, 6 weeks, and 8 weeks post-vasovasostomy. The vasovasostomy specimens were studied with electron microscopy and by histological evaluation. The vasovasostomy was completed in under 90 minutes by using this laser-assisted technique. This procedure offers to the urologist a more simplified and reproducible operation that can be performed easily and with a potential decrease in hospital costs.

Anastomosis, Surgical↗
PubMed1990

Correction of total anomalous pulmonary venous connection below the diaphragm.

Six infants with total anomalous pulmonary venous connection below the diaphragm had correction by modification of conventional surgical technique. Catheterization revealed the confluence of the pulmonary veins draining into a descending vein below the diaphragm. Symptoms of pulmonary venous hypertension and low cardiac output were typical. All had repair with circulatory arrest (average time, 32 minutes). Mobilization of the pulmonary veins and the descending vein is important. The descending vein was transected at the diaphragm. Its anterior surface was incised through the confluence of the pulmonary veins, thus creating an open Y incision. This large Y-shaped vein was anastomosed to the left atrium and carried obliquely to the tip of the left atrial appendage. The anastomosis was fashioned so that the long limb of the Y rotated anteriorly and superiorly to substantially enlarge the left atrium, making the total diameter of the anastomosis larger than the mitral valve orifice. This simplified the surgical repair and allowed direct suture closure of the atrial septal defect in all patients, as the left atrial size was at least doubled. No postoperative complications occurred, and the patients were discharged an average of 4.2 days postoperatively. Restudy at an average of 3.5 years revealed normal pressures and normal architecture by angiography. Use of the descending vein as an integral part of the reconstruction and enlargement of the left atrium was the major technical factor leading to a successful outcome in these patients and eliminating a patch or transposition of the atrial septum.

Anastomosis, Surgical↗
PubMed1990

Prevalence of cardiovascular disease and diabetes mellitus in residents of Rochester, Minnesota.

To determine the prevalence of cardiac disorders as risk factors for stroke, we conducted a survey in 1986 in a stratified random sample of the population of Rochester, Minnesota, 35 years of age or older. The medical records of the 2,122 subjects in the sample were retrieved with use of the Rochester Epidemiology Project medical records linkage system. The data were used to estimate (1) the reliability of self-reported information about cardiac and cerebrovascular disorders and (2) the age- and sex-specific prevalence of diabetes mellitus and various cardiac and cerebrovascular conditions. The estimated prevalence for selected risk factors in the population 35 years of age or older was 5.8% for diabetes mellitus, 3.3% for myocardial infarction, 1.2% for mitral valve disease, 4.2% for left ventricular hypertrophy, and 2.8% for atrial fibrillation or flutter. These data can be used to estimate resources required for evaluation and management of the disorders. When the prevalence and the relative risk for stroke are known for a particular cardiac disorder, the proportion of stroke attributable to that disorder can be estimated.

Adult↗
PubMed1990

Is atrial fibrillation an independent risk factor for stroke?

That non-rheumatic atrial fibrillation is an independent risk factor for cerebral infarction has not been established with certainty. The rationale underlying contemporary clinical trials of warfarin therapy for the prevention of stroke in patients who have non-rheumatic atrial fibrillation is that the majority of strokes in such patients are due to cardiogenic cerebral embolism. However, there is evidence to suggest that the increased probability of stroke attributed to this arrhythmia is due to its association with other risk factors such as hypertension, diabetes mellitus, and atherosclerosis. The question of who should be anticoagulated is a major public health issue since atrial fibrillation is present in approximately ten per cent of the general population aged 65 or more years.

Adult↗
PubMed1989

Disrupted coronary artery caused by angioplasty: supportive and surgical considerations.

Of 2,859 patients having percutaneous transluminal coronary angioplasty, 201 (7%) underwent emergency coronary artery bypass grafting. Two categories of patients were reviewed. Group 1 consisted of 126 patients of 2,304 who had immediate coronary artery bypass grafting after failed elective percutaneous transluminal coronary angioplasty. Ninety-eight of these patients had angiographic evidence of occlusion of a coronary artery, and 28 had angiographic evidence of coronary artery dissection. Epicardial hemorrhage was observed at operation in 20% (25 patients). Three deaths (2.4%) occurred in group 1, and an average of 3.3 grafts was performed per patient. Group 2 comprised 75 of 555 patients who had unsuccessful attempted percutaneous transluminal coronary angioplasty during an evolving myocardial infarction and required immediate coronary artery bypass grafting. Angiography revealed coronary artery occlusion in 61 patients with dissection in 14. All group 2 patients had evidence of myocardial injury by electrocardiographic and enzymatic (myocardial-specific isoenzyme of creatine kinase) criteria. Three deaths (4%) occurred in this group, and there was an average of 3.4 grafts per patient. Percutaneous transluminal coronary angioplasty is routinely performed without surgical consultation, although an operating room and team are usually available. Supportive techniques include the intraaortic balloon pump and percutaneous cardiopulmonary bypass. In those patients with coronary artery dissection, care must be taken to reestablish the true lumen of the coronary artery. Hemopericardium should be surgically explored and broken guidewires or other foreign bodies or debris removed. From 1979 through 1986, the number of patients requiring emergency coronary artery bypass grafting after percutaneous transluminal coronary angioplasty steadily declined to less than 5%.

Angioplasty, Balloon↗
PubMed1989

Use of a double-lumen pressure monitoring catheter to facilitate pulmonary artery banding.

Pulmonary artery banding is facilitated by simultaneously measuring the pressure above and below the band. This can be accomplished with a commercially available double-lumen central venous pressure monitoring catheter. This catheter is inserted through the outflow tract of the right ventricle and positioned so that the band will be between the two lumens. Gradual tightening of the band can be accomplished while monitoring the pressures proximal and distal to the band.

Catheterization, Central Venous↗
PubMed1989

Percutaneous cardiopulmonary bypass: application and indication for use.

Percutaneous cardiopulmonary bypass (CPB) was used in 22 patients: 7 patients with cardiac arrest due to acute myocardial infarction; 4 patients in cardiac arrest because of failed angioplasty; 1 patient for high-risk elective angioplasty; 1 patient with massive pulmonary emboli; 2 patients with hypothermia; 2 pediatric patients (1 with sepsis and 1 in combination with extracorporeal membrane oxygenator support); 1 patient with refractory arrhythmia; and 4 patients with trauma. Percutaneous CPB involves a modified Seldinger technique that is easily applied. All patients except those with massive trauma were resuscitated with the use of percutaneous CPB. One patient requiring a very difficult proposed angioplasty received percutaneous CPB support while triple-vessel angioplasty was performed. Percutaneous CPB appears to be beneficial in resuscitating patients with refractory cardiac arrest or other forms of circulatory collapse except trauma. Limited use for brief periods in high-risk patients having elective angioplasty might be applicable.

Angioplasty, Balloon↗
PubMed1989

The cardiac actin locus (Actc-1) is not on mouse chromosome 17 but is linked to beta 2-microglobulin on chromosome 2.

A restriction fragment variant and recombinant inbred strains were used to show that the cardiac actin locus (Actc-1) is closely linked to beta 2-microglobulin (B2m) and several other loci on chromosome 2 of the mouse. Close linkage of Actc-1 and B2m in both man and mouse provides another example of a chromosomal segment that has been conserved since the divergence of the lineages leading to these two species.

Alleles↗