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Biomedical subjects

A J Leach

Publications and source records attributed to A J Leach.

At least 37 records · Page 2Linked to original sources

Psychosocial aspects of coronary artery disease related to military patients.

OBJECTIVE: Coronary artery disease (CAD) is a major cause of nontraumatic morbidity and mortality in military personnel. Most studies of the psychosocial impact of CAD have dealt with civilian populations. The purpose of this paper is to highlight differences between military and civilian populations with CAD in 4 areas: depression and anxiety, social support, return to work, and stress. METHOD: A computerized literature search from 1985 to 1995 using the search terms "stress," "cardiovascular," "cardiac," "depression," "military," "anxiety" and "psychosocial" was undertaken. Controlled and prospective studies of civilian patients were selected along with relevant studies involving military populations. RESULTS: Unique characteristics of the military may be important factors in affecting the psychosocial outcome of military patients with CAD. These characteristics include a high level of denial of illness, strong social supports, a powerful military work ethic, and stressful situations unique to the military. CONCLUSIONS: Most studies of the psychosocial impact of CAD are based on civilian populations. A review of available studies suggests that little is known about how military patients adapt to CAD, particularly with regard to symptoms of depression and anxiety, social impairment, and rates of return to work. Studies in this area are needed regarding the psychosocial aspects of CAD in military populations.

Adult↗

Adaptation to coronary artery disease: first pilot study in the military.

To determine how a group of 29 male military patients with coronary artery disease (CAD-MIL group) have adapted physically and psychosocially, we compared results from standard questionnaires with those from 39 healthy military men (WELL-MIL group) and 27 male civilian patients with coronary artery disease (CAD-CIV group). There was no difference in the degree of severity of coronary artery disease between the two groups with the disease. The WELL-MIL group reported a higher activity level than the CAD-MIL group, which reported a higher activity level than the CAD-CIV group. Both the CAD-MIL group and WELL-MIL groups had lower levels of state anxiety compared with the CAD-CIV group, and the CAD-MIL group had a better overall psychosocial adjustment score compared with that of the CAD-CIV group. Thus, male military patients with coronary artery disease reported better physical and psychosocial adjustment to their illness than a group of male civilian patients with a similar degree of disease severity. but they were less physically active than healthy military men.

Adaptation, Psychological↗

Coronary bypass graft fate and patient outcome: angiographic follow-up of 5,065 grafts related to survival and reoperation in 1,388 patients during 25 years.

OBJECTIVES: We sought to examine, angiographically, the longterm fate of a large number of mainly venous coronary bypass grafts and to correlate graft patency and disease with patient survival and reoperation. BACKGROUND: Much is known about bypass graft patency and disease, but the precise relation between graft fate and patient outcome has not been substantiated and documented. METHODS: A total of 1,388 patients underwent a first coronary artery bypass graft procedure at a mean age of 48.9 years, 234 had a second bypass procedure at a mean age of 53.3 years, and 15 had a third bypass procedure at a mean age of 58.2 years during the 25-year period from 1969 to 1994. Most were male military personnel or veterans; 12% were < or = 39 years old. Of 5,284 grafts placed, 91% were venous and 9% arterial. Angiograms were performed on 5,065 (98% of surviving) grafts early, on 3,993 grafts at 1 year and on 1,978 grafts at 5 years after operation; other examinations were also performed up to 22.5 years after operation, and 353 grafts were examined after > or = 15 years. Grafts were graded for patency and disease. The status of all patients was known at the study's end. RESULTS: The perioperative mortality rate was 1.4% for an isolated first coronary bypass procedure, 6.6% for reoperation. Vein graft patency was 88% early, 81% at 1 year, 75% at 5 years and 50% at > or = 15 years; when suboptimal grafts, graded B, were excluded from calculation, the proportion of excellent grafts, graded A, decreased to 40% after > or = 12.5 years. After the early study, the vein graft occlusion rate was 2.1%/year. Internal mammary artery graft patency was significantly better but decreased with time. Vein graft disease appeared by 1 year and the rate accelerated by > or = 2.5 years, involving 48% of grafts at 5 years and 81% at > or = 15 years; 44% of the latter grafts were narrowed > 50%. Survival of all patients was 93.6% at 5 years. 81.1% at 10 years, 62.1% at 15 years, 46.7% (150 patients) at 20 years and 38.4% (25 patients) at 23 years after operation. Survival decreased as age increased, but curves approximated "normal" life expectancy for older patients. Survival curves at all ages showed a steeper decline after 7 years. The rate of reoperation increased between 5 years and 10 to 14 years, then decreased to stable levels. Coronary atheroembolism from vein grafts was the major cause of morbidity and mortality associated with reoperation. Vein graft patency and disease were temporally and closely related to reoperation and survival. CONCLUSIONS: Coronary bypass graft disease and occlusion are common after coronary artery bypass grafting and increase with time. They are major determinants of clinical prognosis, specifically measured by reoperation rate and survival. Intraoperative graft atheroembolism was a major reoperation hazard. Reoperation is definitely worthwhile but entails identifiable risks that must be dealt with.

Adult↗

Carriage of multiple ribotypes of non-encapsulated Haemophilus influenzae in aboriginal infants with otitis media.

Ribotyping with the restriction enzyme XbaI was used to study the dynamics of Carriage of non-encapsulated Haemophilus influenzae (NCHi) in Aboriginal infants at risk of otitis media. Carriage rates of NCHi in the infants in the community were very high; the median age for detection was 50 days and colonization was virtually 100% by 120 days of age and persisted at a high level throughout the first year of life [1]. Eighteen different ribotypes of NCHi were identified from 34 positive swabs taken from 3 infants over a period of 9 months. The same ribotypes were recovered for up to 3 months from consecutive swabs of individual infants, and 12 of 27 swabs (44.4%) yielded two ribotypes from four colonies typed. Statistical analysis suggested that most swabs would have been positive for two ribotypes if enough colonies had been typed although the second most frequent ribotype was detected on average in only 13% of strains. Early colonization and carriage of multiple ribotypes of NCHi may help to explain the chronicity of carriage and thus the persistence of otitis media in Aboriginal infants.

Bacterial Typing Techniques↗

Streptococcus pneumoniae carriage and penicillin/ceftriaxone resistance in hospitalised children in Darwin.

BACKGROUND: The prevalence of resistant Streptococcus pneumoniae (SP) is increasing world-wide. Pneumococcal prevalence and susceptibility patterns are not known for children in the Top End of the Northern Territory. AIMS: To determine the prevalence of nasopharyngeal carriage of pneumococci in children hospitalised in Darwin, and the extent of penicillin and ceftriaxone resistance in these isolates. METHODS: Nasopharyngeal swabs were collected on admission from 85 children who had not received antimicrobials for their admission illness. Antimicrobial resistance was determined following selective culture for SP isolates. Minimal inhibitory concentrations (MICs) for penicillin and ceftriaxone were determined using the E-test method. RESULTS: The overall prevalence of nasopharyngeal SP carriage was 44%. Carriage occurred more often in Aboriginal children from rural areas (56%) than in urban children (24%) (OR 3.94, 95% CI 1.35-11.78, p < 0.01). Thirty per cent of isolates were penicillin resistant, 35% were ceftriaxone resistant, and 49% were resistant to at least one of these. One isolate showed high-level resistance to both antimicrobials; all other resistant isolates were of intermediate-level resistance. For the same isolate, MICs for ceftriaxone were more often higher than those for penicillin. Five isolates had intermediate resistance to ceftriaxone whilst remaining sensitive to penicillin. CONCLUSIONS: The prevalence of pneumococcal resistance to penicillin and ceftriaxone in hospitalised children in Darwin is much higher than previously reported in Australia. This has implications for future antimicrobial management and highlights the need for regular regional surveillance of SP resistance. The development of conjugate pneumococcal vaccines for children under two years is a priority.

Ceftriaxone↗

Health services market testing--the experience of the community services review team in British Forces Germany.

During 1993-1995 the health services in British Forces Germany were subjected to a market testing process by which the primary, community and acute health services for the British Servicemen and women, their families and attached civilian staff, a population of 70,000, were put out to competitive tender with the then current provider, the Defence Medical Services, as one tenderer for the contract. This paper outlines the methodology developed by the Health Alliance Community Services Review team in formulating a successful bid. It is considered that the process outlined could be of value to those involved in future market tests, commissioning projects or performance improvement programmes.

Community Health Nursing↗

Interventions for coronary stenosis--a Canadian experience of 30 revolutionary years.

OBJECTIVE: To report 2324 coronary stenosis interventions (Vineberg procedures [VbP], coronary artery bypass graft operations [CABG] and percutaneous transluminal coronary angioplasties [PTCA]), in 1711 patients of a Canadian military hospital between 1965 and 1995 and to report their evolution and interaction in a historical context. DESIGN: Retrospective examination of clinical and angiographic findings in hard records, collected from the beginning for long term follow-up and later embedded in a custom-designed computer database. PATIENTS: Most were male, mean ages 43.2 and 43.3 years for first and second VbPs; 48.9 and 58.2 years for first and repeat CABGs; and 53.4 and 59.9 years for first and repeat PTCAs, respectively; 12% of all patients were 39 years old or younger at the first intervention. INTERVENTIONS: There were 160 VbPs, 1637 CABGs and 527 PTCAs. Of 1711 subjects, 74% had only one procedure, 15% had more than one of the same kind, and 11% had more than one of different kinds. MAIN RESULTS: Perioperative mortality for VbPs was 4.4%; for 'isolated' first CABGs it was 1.4% and 6.6% for reoperations, when other concurrent major cardiac procedures, excepting ventricular aneurysm repair, were excluded. It was 0.4% for PTCAs. Perioperative mortality for all 1761 'isolated' coronary interventions necessitating thoracotomy, during 30 years, was 2.4%. Angiographic follow-up rates were high and some findings are reported, including early postoperative patency rates for 5065 coronary bypass grafts, and long term follow-up data on graft patency and disease. CONCLUSIONS: Each intervention was used to circumvent or relieve coronary stenosis, in the early years when it became available and, later, as was most appropriate for dealing with specific clinical problems. The impact of advances in the evolution of these interventions on therapeutic decision-making is discussed. Finally, tributes are paid to those responsible for making these procedures possible, including a Canadian surgeon whose role was pivotal.

Adult↗

Exercise echocardiography after coronary artery bypass surgery: correlation with coronary angiography.

OBJECTIVES: Our aim was to assess, in patients after coronary artery bypass surgery, how well exercise echocardiography predicts the presence of vascular compromise on angiography. BACKGROUND: Because late graft failure frequently occurs after bypass surgery, a reliable noninvasive technique is needed to identify those patients who would benefit from angiographic study. METHODS: In 182 patients, a total of 213 symptom-limited treadmill exercise electrocardiograms (ECGs) and exercise echocardiograms were performed in association with coronary and bypass angiography 2 weeks to 21 years after bypass surgery. RESULTS: There were more inconclusive exercise ECGs (28%) than exercise echocardiograms (9%). The positive predictive value was 85% for the exercise echocardiogram versus 62% for the exercise ECG; the corresponding negative predictive values were 81% versus 52%. The accuracy of the exercise echocardiogram was linked to the degree of underlying vascular compromise. After excluding cases with nondiagnostic results, due to either submaximal stress or poor image quality, the exercise echocardiogram detected 46 of the 60 cases with vascular compromise in one region (sensitivity 77%) and 47 of the 49 cases with compromise in two or three regions (sensitivity 96%). Similarly, an abnormal exercise echocardiogram had a positive predictive value of 71% for vascular compromise in one region and 98% for compromise in two or three regions. Most false negative exercise echocardiographic results were associated with posterolateral single-region vascular compromise on angiography. CONCLUSIONS: This study confirms a high positive and negative predictive value of exercise echocardiography in the detection of vascular compromise in patients after bypass surgery. It is clearly superior to exercise electrocardiography in predicting which patients will have angiographically significant graft or arterial lesions, and it can be used to obtain a better selection of patients for angiographic study.

Coronary Angiography↗

Aortocoronary vein graft spasm during angiography.

OBJECTIVE: To determine the frequency and clinical significance of aorto-coronary vein graft spasm during angiography. DESIGN: Retrospective review of angiograms and subsequent correlation with clinical outcome. PATIENTS: A total of 1264 patients having bypass surgery between 1971 and 1986. MAIN RESULTS: Twenty-four men, aged 31 to 54 years, demonstrated spasm in 31 vein grafts at angiography. Vein graft spasm occurred in 13 anterior descending, 12 right coronary, four marginocircumflex and two diagonal grafts. Spasm occurred less than six months after surgery in six cases, six to 12 months after surgery in 18 cases and five or more years after surgery in two cases. There was technical difficulty associated with the intubation of 15 of the 31 grafts. In all but two of the cases, the graft spasm was proximal. There was ischemic discomfort and/or electrocardiographic changes in nine patients, with ventricular fibrillation in three cases. Three cases of very severe vein graft spasm could be reversed with vasodilators, but in three others it could not be relieved and the grafts occluded irreversibly, leading to myocardial infarction in two patients. CONCLUSION: Aortocoronary vein graft spasm may occur during angiography and may be associated with more technically difficult graft intubation. Severe vein graft spasm may respond to vasodilators but can progress to graft occlusion with myocardial infarction. Aortocoronary vein graft spasm during angiography is not related to any higher incidence of spontaneous graft closure or recurrent angina.

Adult↗

Bacterial colonization of the nasopharynx predicts very early onset and persistence of otitis media in Australian aboriginal infants.

Otitis media (OM) develops in the first months of life and persists throughout childhood in many rural Aboriginal children. We have followed Aboriginal and non-Aboriginal infants from birth to determine the relationship of the early onset of OM to nasopharyngeal colonization with respiratory pathogens. Aboriginal infants were colonized with multiple species of respiratory bacteria (Moraxella catarrhalis, Haemophilus influenzae, Streptococcus pneumoniae) at a rate of 5% per day and the timing of colonization predicted the onset of persistent OM in individual Aboriginal infants. Non-Aboriginal infants became colonized by M. catarrhalis alone at the slower rate of 1% per day and experienced transient episodes of OM in the absence of colonization. We attribute early bacterial colonization in most Aboriginal infants to high rates of cross-infection due to overcrowding, poor hygiene and high rates of bacterial carriage. Early age of infection and the multiplicity of bacterial types may contribute to prolonged carriage and to eustachian tube damage leading to persistent OM. Thus Aboriginal infants are "otitis-prone" and might qualify for prophylactic antibiotics.

Age Factors↗

Coronary bypass graft fate: long-term angiographic study.

In 222 patients, 741 venous coronary bypass grafts were studied angiographically early, at 1 year and at a late examination at greater than 6.5 years (mean 9.6) after operation; 565 of these grafts were also examined 5 years postoperatively. Grafts were graded for patency and disease considered to be atherosclerotic and for both extent and profile of lesions. Graft occlusion rates increased steadily from 8% early to 20% at 5, 41% at 10 and 45% at greater than 11.5 years after operation. All grafts were considered free of atherosclerosis early, but disease appeared in 8% at 1 year, increasing to 38% at 5 and 75% at 10 years postoperatively. Increasing involvement of vessel wall area was associated with greater protrusion of lesions into the graft lumen. Diseased grafts became more so at subsequent examinations, with occlusion occurring in many. However, absence of disease had little prognostic significance because diseased and abruptly occluded grafts were generated in those with healthy appearance at earlier examinations. For instance, 82% of very diseased grafts at the 5 year study originated from normal grafts at 1 year and 73% of occluded grafts at 1 year had appeared normal early postoperatively. Of 590 patent grafts free of disease at 1 year, 30% were occluded at the late examination, 76% of those patent were diseased, 55% of these were diffusely diseased and 35% were greater than 50% narrowed. Only 17% of the original 590 patent grafts were healthy at this time. Bypass graft atherosclerosis severely limits the long-term utility of these grafts. It is suggested that the solution may lie in some powerful drug regimen.

Adult↗

Atherosclerosis of coronary artery bypass grafts and smoking.

Follow-up angiography was performed at selected intervals on 340 men who had undergone coronary artery bypass surgery. There were 1160 grafts, but 112 were excluded from study because they occluded shortly after the operation. After 5 years 115 patients were smokers and 225 were nonsmokers. The mean number of grafts per patient was similar in the two groups. We classified each graft according to irregularities in graft outlines and graft patency and found disease-free grafts in 39% of the smokers and 52% of the nonsmokers; the proportion of diseased or occluded grafts was greater in the smokers than in the nonsmokers. Our results do not identify the effect of smoking cessation after bypass surgery, but they do suggest that men who continue to smoke are at significantly greater risk of atherosclerosis and occlusion than nonsmoking men.

Angiography↗

Coronary artery disease and coronary bypass grafting in young men: experience with 138 subjects 39 years of age and younger.

One hundred thirty-eight men aged less than or equal to 39 years had coronary bypass grafting during a 13 year period. Angina was the presenting symptom in 77% and of these patients, one-third had unstable angina. More than half of the patients had experienced at least one myocardial infarct. There was a high incidence of coronary risk factors, especially smoking. Nineteen patients (13.8%) had left main coronary artery stenosis (it was isolated in two); 13.8, 24.6 and 60.2% had single, double and triple vessel disease, respectively. Left ventriculograms showed serious functional impairment in 42%. A total of 461 coronary bypass grafts, 3.34 per patient, were placed; almost all were vein grafts. There were no operative deaths. Transmural myocardial infarction occurred in 4.3% of patients. All bypass grafts were opacified angiographically early after operation, 95% at 1 year, 56% at 5 years and 26% at 10 years after operation. Some patients also had coronary angiograms, dictated by clinical events, between 1 and 5 and between 5 and 10 years postoperatively. Patency rates for bypass grafts were comparable with those previously reported and were acceptable, although they decreased with time. However, increasing evidence of atherosclerosis of bypass grafts was seen beyond 1 year, particularly beyond 5 years. Of 23 subjects with a coronary bypass reoperation, 2 died and 44% had perioperative transmural myocardial infarction. During follow-up, 13.8% of the patients died, survival being 95, 84 and 76% at 5, 10 and 12 years, respectively. It is considered that the patients were advantageously treated with coronary bypass grafting especially in the short-term. However, bypass graft patency steadily decreased with the passage of time and graft atherosclerosis became an increasingly important problem.

Adult↗

Coronary bypass graft fate. Angiographic study of 1,179 vein grafts early, one year, and five years after operation.

A total of 1,179 vein grafts were studied angiographically in 353 (45%) unselected survivors (male, mean age 45.5 years) of 786 coronary bypass operations. Studies were conducted early (0.96 months), 1 year (12.8 months), and 5 years (59.7 months) postoperatively. A previously described technique was used to grade the patency of the grafts, and a new technique was used to assess intimal irregularity, presumably caused by atherosclerosis; this new technique indicated both intimal surface distribution of disease and profile (relief or elevation). Ten percent, 17%, and 26% of grafts were occluded early, at 1 year, and at 5 years, respectively. Distal anastomotic defects were the commonest cause for low grades in the patency classification. Irregularities in patent grafts increased from 9% at 1 year to 42% at 5 years, with 11% of all the 1 year lesions and 20% of all the 5 year lesions having a high profile (more than 50% graft stenosis); of the lesions categorized as showing the widest surface spread, 17% were in high relief at 1 year and 34% at 5 years. Thus, the lesions we believed to be atherosclerotic proliferated in both surface spread and elevation. All severely diseased grafts at the 1 year study had been normal in outline early; 79% at the 5 year study had been disease free at 1 year. All newly occluded grafts at the 1 year study had been normal in outline and 82% had had good patency early; 78% of newly occluded grafts at the 5 year study had been disease free at 1 year and 77% had had good patency. Normal appearance of the intima in grafts studied at 1 year had no prognostic value for 5 year findings. However, 62% of all grafts with the appearance of intimal disease at 1 year showed deterioration by 5 years, and 28% were occluded. The differences between these outcomes are highly significant (p less than 0.0005). In conclusion, the appearance of intimal irregularity compatible with atherosclerosis in a coronary bypass graft 1 year after operation carried a poor prognosis for adverse angiographic change at 5 years. On the other hand, normally appearing intima at 1 year had no predictive valve for the 5 year study despite a generally better prognosis for nondiseased grafts.

Adult↗

Perioperative myocardial infarction complicating coronary bypass. Clinical and angiographic correlations and prognosis.

To investigate the importance and the causes of myocardial infarction complicating the coronary bypass operation, we have reviewed clinical and preoperative angiographic data on 717 patients operated on over an 81/2 year period and postoperative angiography on all but one survivor. The hospital mortality was 0.6%. Of the 56 (7.8%) patients who sustained perioperative myocardial infarction, two died. Left ventricular angiography supported the diagnosis in 40 patients and aided in quantification of myocardial infarction. Age, preoperative symptomatic status, incidence of prior myocardial infarction, and perfusion and axoxia timed did not correlate with myocardial infarction, but extent of coronary disease, number of grafts, and associated endarterectomy did. There have been no late deaths in the 54 survivors of perioperative infarction, which appears usually to be a benign event. Graft occlusion was nearly three times commoner in patients with myocardial infarction, and in 42 of 54 survivors the myocardial infarction could be explained by new impairment of perfusion, usually owing to compromise of the grafted artery. The relationship of perioperative infarction to iatrogenic diminution of perfusion, of the infarcted segment suggests that technical factors, especially meticulous attention to the quality of the graft-coronary artery anastomosis might further reduce the perioperative infarction rate.

Coronary Angiography↗

Cardiac depression by intravenous disopyramide in patients with left ventricular dysfunction.

The hemodynamic effects of disopyramide phosphate were studied in nine patients with left ventricular dysfunction. After control measurements, administration of a 2 mg/kg bolus of disopyramide phosphate over 5 or 15 minutes was followed by a 20 minute 0.4 mg/kg/hour infusion and a 15 minute recovery period. Response to the 5 and 15 minute bolus injection was similar. Maximum hemodynamic effects occurred immediately after the bolus was given; there were decrements in systolic pressure (142 to 124 mm Hg)(p less than 0.005), cardiac index (2.5 to 1.8 liters/min/m2)(p less than 0.001) and stroke index (29.4 to 20.6 ml/beat/m2)(p less than 0.001), and increases in right atrial pressure (9 to 12 mm Hg)(p less than 0.005) and total peripheral resistance (21.2 to 25.7 U)(p less than 0.005). Two studies had to be terminated after the bolus was given due to profound hemodynamic deterioration. In the remainder, the systolic pressure returned to control by the end of the infusion, whereas the mean arterial pressure increasd significantly (92 to 96 mm Hg)(p less than 0.01). Little further change in mean arterial pressure, cardiac and stroke index, and total peripheral resistance occurred during the recovery period. These data indicated that intravenous disopyramide phosphate is a potent cardiac depressant when given over 5 to 15 minutes to patients with left ventricular dysfunction. It is concluded that disopyramide should not be administered to such patients unless conventional therapy fails. In such circumstances it should be used with extreme caution and careful monitoring.

Aged↗