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Biomedical subjects

J K Ross

Publications and source records attributed to J K Ross.

At least 55 records · Page 3Linked to original sources
PubMed1981

Ultrastructural changes in spontaneous rupture of mitral chordae tendineae.

Mitral valves from ten patients with spontaneous rupture of mitral chordae were examined by light, scanning and transmission electron microscopy. Changes identified at rupture sites included oedema and necrosis of collagen, endothelial loss and, in some cases, partial or complete re-endothelialisation of the disrupted ends. With a solitary exception these abnormalities were confined to chordae which had actually ruptured. Some non-ruptured chordae were irregularly thinned and stretched but were normal by light and electron microscopy. Mucoid degeneration was almost invariable in mitral valve leaflets. These results suggest that spontaneous chordal rupture is more likely to be the result of abnormal mechanical strain rather than a diffuse connective tissue abnormality affecting multiple chordae. They may also provide theoretical justification for reconstruction rather than replacement of mitral valves in this condition.

Aged↗
PubMed1981

The effect of dietary citrus pectin on the excretion of human fecal neutral and acid steroids and the activity of 7alpha-dehydroxylase and beta-glucuronidase.

The purpose of this study was to investigate the effects of citrus pectin on human fecal neutral and acid steroid excretion and beta-glucuronidase and 7alpha-dehydroxylase activity. Eight healthy male subjects (age 20 to 27 yr) were used in a switchback design with or without 15 g citrus pectin added to a mixed low fiber diet. There were three successive 18-day periods preceded by a 4-day adjustment period. Half of the subjects followed a pectin-nonpectin-pectin protocol and the other half followed a nonpectin-pectin-nonpectin protocol. Fecal samples were collected throughout the study under anaerobic conditions. Compared to the control diet, mean fecal weight, percentage moisture, transit time, and fecal fat for both groups of subjects were not significantly different by analysis of variance when subjects were fed pectin diet. Mean beta-glucuronidase activity was increased (35%) when subjects were fed the pectin. Mean 7alpha-dehydroxylase activity showed no definite trend. Mean neutral steroid concentration was slightly decreased (8%) when the pectin diet was fed but total excretion was unchanged. End of period neutral steroid concentration was decreased 9% and total excretion was decreased 3.5%. Mean acid steroid concentration was not changed but total excretion was increased (11%) on the pectin diet. End of period acid steroid concentration and excretion was increased 6% on the pectin diet. This study shows that there were interrelationships between dietary pectin, neutral and acid steroid metabolism, and bacterial enzyme activity.

Adult↗
PubMed1981

Homograft aortic valve replacement: seven years' experience with antibiotic-treated valves.

One hundred and sixty-five patients had their aortic valve replaced with antibiotic-sterilised homograft. In all cases, a two-layered freehand technique of valve implantation was used. Tailoring (narrowing) of the annulus was required in 29 cases, and an aortic root gusset was used to enlarge the non-coronary sinus in 68 cases. There was an early mortality of 1.8% and late mortality of 2.4%. The actuarial survival rate was 95% at a maximum follow-up of seven years. The incidence of valvar regurgitation (early diastolic murmur) was 11.5% up to six months after operation and an additional 7.2% subsequent to this. Overall, it was trivial in 10.3%, mild in 7.8%, and moderate in 0.6%. Most valve regurgitation was non-progressive and actuarial analysis showed 74% regurgitation-free valves at the end of seven years. The age of the donor and the valve storage time showed some relationship to valve deterioration. Special attention has been paid to the control of hypertension to prevent accelerated graft degeneration. The results suggest that this has been successful. Anticoagulant therapy was not used and thromboembolism has not been seen in patients undergoing isolated aortic valve replacement. There was one case of miliary tuberculosis after homograft valve replacement but no pyogenic or fungal endocarditis occurred. No haemolysis, calcification, or valvar stenosis were observed. This series, followed for a maximum of seven years, shows excellent sustained valve performance and a very low incidence of important postoperative regurgitation, with 91.8% of the survivors symptom-free.

Adolescent↗
PubMed1979

Surgery of the ascending aorta: five years' experience at a regional cardiac centre.

Between 1972 and 1978, 31 patients underwent replacement of the ascending aorta, with or without aortic valve surgery, at the Wessex Regional Cardiac Centre. The commonest indications for operation were aneurysmal dilatation of the ascending aorta causing aortic regurgitation and acute dissection of the ascending aorta. Eleven of the 31 patients had features of Marfan's syndrome. The overall hospital mortality was 19.4%, a figure comparable with those reported in other series; ventricular failure secondary to ischaemia during operation was the commonest cause of death. The long-term symptomatic results were excellent, except in the two patients who underwent resuspension of the aortic valve for aortic regurgiation associated with acute dissections. For aneurysms of the ascending aorta with associated aortic regurgitation, replacement of the valve and ascending aorta with a combined valve prosthesis and synthetic tube graft, with reimplantation of the coronary ostia, is the procedure of choice if the aortic valve ring is diseased. Experience to date indicates that replacement of the ascending aorta and aortic valve with separate prostheses, leaving the coronary ostia undisturbed, is a satisfactory alternative provided the aortic annulus is of suitable size and quality; this is more likely to be the case in dissections than in aneurysmal dilatation of the ascending aorta. Replacement of the ascending aorta may also be indicated in some cases of dilatation of the ascending aorta secondary to aortic valve disease if the aortic wall is unusually thin.

Adult↗
PubMed1978

The cost of cardiac surgery.

A study in Wessex has shown that at 1977 prices, and excluding the cost of equipment already installed in the unit, the cost of replacing a man's aortic valve in this unit is about 1800 pounds. Nevertheless, this seems a small price to pay for return to health and full working capacity, particularly since such patients no longer need to draw social security benefits and their tax contributions will return to normal, thus probably paying for the operation within two years.

Adult↗
PubMed1977

Pulmonary hypertension in mitral valve disease: 56 surgical patients reviewed.

A total of 392 patients have undergone prosthetic valve surgery including the mitral valve over a four-year period (1972-76). Of these patients 56 (14%) had a pulmonary artery systolic pressure of 70 mmHg or more during preoperative cardiac catheterisation and the hospital mortality of this group was 5.4%. Similarly, the hospital mortality of the remaining 336 patients with a pulmonary artery pressure below 70 mmHg was 5.4%. The presence of pulmonary hypertension in patients with valve disease including the mitral valve does not therefore indicate that the risk of dying in hospital as a consequence of corrective surgery is increased. The absence of a raised hospital mortality in this recent series may be attributed to improved surgical techniques and materials, while the use of droperidol and pentolinium which may reduce pulmonary vascular resistance as well as systemic resistance during surgery could be contributory.

Adult↗
PubMed1976

Intraoperative left ventricular perforation with false aneurysm formation.

Two cases of perforation of the left ventricle during mitral valve replacement are described. In the first case there was perforation at the site of papillary muscle excision and this was recognized and successfully treated. However, a true ventricular aneurysm developed at the repair site. One month after operation rupture of the left ventricle occurred at a second and separate site on the posterior aspect of the atrioventricular ring. This resulted in a false aneurysm which produced a pansystolic murmur mimicking mitral regurgitation. Both the true and the false aneurysm were successfully repaired. In the second case perforation occurred on the posterior aspect of the atrioventricular ring and was successfully repaired. However, a false ventricular aneurysm developed and ruptured into the left atrium producing severe, but silent, mitral regurgitation. This was recognized and successfully repaired. The implications of these cases are discussed.

Echocardiography↗
PubMed1976

Elective operations for post-infarction left ventricular aneurysms.

During a two-year period (February 1973 to February 1975) 20 consecutive patients with post-infarction left ventricular aneurysm, seen at the Wessex Cardiac and Thoracic Centre, underwent aneurysmectomy with or without aorta-to-coronary artery saphenous vein bypass grafts, ventricular septal defect closure, or valve replacement. The diagnoses were established by clinical means, plain chest radiographs, left ventriculography, and selective coronary arteriography. The indications for surgery were uncontrollable congestive heart failure and angina, ventricular arrhythmias, or a rapidly growing aneurysm. Low cardiac indices or high left ventricular end-diastolic pressure were not considered to be contraindications to operation. Resection of the left ventricular aneurysm was performed with the use of normothermic cardiopulmonary bypass with haemodilution. In addition to the aneurysmectomy, four of these patients had concomitant closure of post-infarction ventricular septal defects; four had valve replacements; two had grafts to coronary arteries; and one had both replacement of the mitral valve and a right coronary vein graft. There were two hospital deaths (10%) and two late deaths (10%), making an overall mortality of 20%. All but one of the deaths were related to coronary artery disease. The survivors are active, and their rehabilitation was satisfactory. The longest survivor is doing well two years after left ventricular aneurysmectomy, ventricular defect closure, and tricuspid valve replacement. It is evident from our experience and from the reports of others that surgery has an established place in the management of post-infarction left ventricular aneurysm.

Adult↗
PubMed1976

Mitral valve reconstruction by posterior cusp advancement using a pericardial graft. Long-term follow-up in nine patients.

Between December 1964 and March 1969, 11 posterior cusp advancement operations were carried out for patients with mitral valve disease in whom there was posterior cusp deficiency. Seven of the nine long-term survivors have required reoperation for recurrent mitral regurgitation, combined in six instances with stenosis of varying severity, the interval between the first and second operations ranging from five months to nine years (average 57-5 months). Histological examination of the pericardial grafts recovered at re-operation has been made and shows that after an initial period during which the graft retains near normal structure, there is a progressive degeneration with fibrous tissue replacement. This process takes place on both surfaces of the graft where there is evidence of vascularization in the zone between the graft remnant and the overlying and increasingly thick fibrous tissue covering. The conclusion drawn from the experience with this small series is that the long-term performance of pericardial grafts designed to restore function to the posterior cusp of the mitral valve is poor and unpredictable.

Adult↗
PubMed1975

Late complications of surgery for coarctation of the aorta.

The problem of the patient who has had one operation for coarctation of the aorta and who then requires another because of a late complication at or near the coarctation site is a demanding one. The safety of aortic cross-clamping at the second operation depends on the adequacy or otherwise of the collateral circulation, and this in turn depends on the presence or absence of residual or recurrent aortic obstruction. Three illustrative cases are described in which there was complete, incomplete, and no aortic obstruction respectively at the time of reoperation, two of the cases presenting the additional complication of local aneurysm formation. The various aspects of management of such individuals are discussed, and the relevant literature has been reviewed in an attempt to provide a systematic approach to these difficult patients. The methods for assessing collateral circulation are both clinical and radiological with trial clamping of the aorta and pressure measurement as the most reliable ultimate test. A pressure of 50 mmHg in the distal aorta is accepted as indicating an adequate peripheral circulation, but it is recommended that the trial clamping should always include both the left subclavian artery and any particularly large local collaterals. The use of a perfusion technique to sustain the distal tissues is also recommended, although local bypass shunts have a place when their use is dictated in the interests of safety for the patient.

Adolescent↗