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Biomedical subjects

J L Monro

Publications and source records attributed to J L Monro.

At least 91 records · Page 5Linked to original sources

The surgical treatment of restrictive cardiomyopathy in pseudoxanthoma elasticum.

A patient with pseudoxanthoma elasticum presented in pulmonary oedema with restrictive left ventricular cardiomyopathy caused by calcified endocardial bands that were confirmed on echocardiography and at catheterisation. The bands were resected as far as possible and the involved mitral valve was replaced by a heterograft. A year later calcification of the heterograft forced its replacement by a St Jude prosthesis. Relief of symptoms has been good in the medium term.

Adult↗

Surgical management in tetralogy of Fallot and vascular ring.

The management of three infants born with a combination of tetralogy of Fallot and a vascular ring causing tracheoesophageal compression is described. There was a double aortic arch in two patients and an aberrant left subclavian artery with left ligamentum arteriosum and right aortic arch in one. Single-stage corrective surgery of both lesions during infancy, performed under profound hypothermia and circulatory arrest, was successful. In our opinion, this is the treatment of choice, when the anatomy of the tetralogy is favorable for primary correction.

Aorta↗

Closure of ventricular septal defect through the pulmonary artery.

A transpulmonary arterial approach to the closure of a high ventricular septal defect (VSD) has been used, between 1978 and 1982, in eight patients. The reasons were ease of access and the wish to overcome the problems associated with right ventriculotomy. The patients' ages ranged from three weeks to 15 months, their weight from 2.9 kg to 9 kg. The approach was used both when the VSD was an isolated anomaly and when there were major associated defects. It is in this latter group, four with aortic arch anomalies, two with additional double outlet right ventricle (DORV), that avoidance of ventriculotomy was most helpful. It was especially important in the two patients with DORV and a perimembranous, outlet subpulmonary VSD, where it was possible to close off the left ventricular outflow tract and pulmonary valve using a patch, without opening the right ventricle, which was subsequently to become the systemic ventricle. This technique obviates the need for ventriculotomy in the closure of some perimembranous outlet and doubly committed subarterial VSDs, and is the approach of choice for the closure of a perimembranous, outlet, subpulmonary VSD in DORV.

Double Outlet Right Ventricle↗

Eleven year experience of aortic valve replacement with antibiotic sterilized homograft valves in Southampton.

Aortic valve replacement with an antibiotic-treated aortic valve homograft was performed in 200 patients between April 1973 and December 1984. In all cases, a two-layered freehand technique of valve implantation was used. Tailoring of the annulus was performed in 39 cases and a gusset in the non-coronary sinus was used to maintain the shape of the aortic root in 67 patients. There were 6 early deaths (3%) and 14 late deaths (7.2%); 4 of these were related to homograft regurgitation. The 11 years survival rate on actuarial analysis was 83%. The overall incidence of early diastolic murmurs was 27.3%; being significantly higher in those with tailored roots (P less than 0.001). Severe homograft aortic valve incompetence requiring re-operation developed in 3.1%. Anticoagulant therapy was not used routinely, and there was no major thromboembolic episode in those who had isolated homograft aortic valve replacement. There was one case of miliary tuberculosis but pyogenic and fungal endocarditis were not encountered. No hemolysis, valvular calcification or stenosis was observed.

Adolescent↗

Oral verapamil fails to prevent supraventricular tachycardia following coronary artery surgery.

A prospective randomised trial was performed on 100 patients undergoing coronary artery bypass grafting without concomitant procedure. The study group commenced oral verapamil 40 mg three times daily on the first post-operative day while the control group received no antiarrhythmic agents. The pre-operative characteristics of both groups were similar with the exception of the incidence of hyperlipidemia which was greater in the verapamil group (P = 0.04). Myocardial protection was achieved with cold crystalloid cardioplegia. Cardiopulmonary bypass times, aortic cross clamp times and graft numbers were similar for both groups. Nine patients were excluded on the first post-operative day; the remainder were studied for 8 days. Supraventricular tachyarrhythmias (atrial fibrillation, atrial flutter or paroxysmal supraventricular tachycardia) were detected in 8 patients in the study group (n = 44) and in 5 patients in the control group (n = 47). The difference was not significant (P = 0.3). The ventricular rate in patients taking verapamil who developed supraventricular tachycardia was 138 +/- 14.9 compared with 156.8 +/- 17.9 in the control group, but the difference failed to reach significant levels (P = 0.065). In conclusion, prophylactic oral verapamil 40 mg given three times daily after coronary artery surgery failed to decrease the incidence of post-operative supraventricular tachycardia or to significantly influence the ventricular rate if tachycardia developed.

Administration, Oral↗

The use of glycerol-preserved homologous dura mater grafts in cardiac surgery: the Southampton experience.

Dura mater obtained from human cadavers and preserved in glycerol was used as patch grafts in various positions in the repair of acquired and congenital cardiac defects in 107 patients over a four-year period. The ages of the recipients ranged from 2 days to 75 years. The mean duration of preservation of the dura mater before use was 25.2 +/- 8.1 weeks. The dural grafts were used as an aortic root gusset in 38 patients (35.5%) undergoing aortic valve replacement, for enlargement of the pulmonary artery or right ventricular outflow tract or both in 38 patients (35.5%), and for repair of coarctation of the aorta in 10 patients (9.4%). The grafts also were used for closure of atrial septal defects, for a variety of other congenital cardiac anomalies, and for replacement of segments of the aorta (2 patients). There were no complications attributable to the use of dura mater. Dura mater preserved in glycerol would seem to be a suitable material for repair of various cardiac defects because of its strength, low antigenicity, athrombogenicity, ease of handling, availability in large sizes, and rapid bonding to host tissue. However, long-term follow-up is important to assess the lasting properties of dura mater.

Adolescent↗

Study of the risk factors related to early mortality following combined mitral valve replacement and coronary artery bypass grafting.

Combined mitral valve replacement (MVR) and coronary artery bypass graft (CABG) operation was performed in 62 consecutive patients at the Wessex Cardiothoracic Centre, Southampton, from 1972 to 1983. There were 43 men and 19 women. The mean age was 61 years. Ten patients were in New York Heart Association (NYHA) functional class II, 34 in class III and 18 were in functional class IV. Mitral regurgitation was predominant in 50 patients and mitral stenosis in 12. Emergency operations were performed in 9 patients and elective operations in 53. There were 5 operative deaths (8.06%), 2 in patients having elective operations (2/53 = 3.7%) and 3 in those having emergency operations (3/9 = 33.3%). Significant factors related to early death were NYHA functional class, timing of surgery, etiology and type of valve lesion, increased pulmonary vascular resistance and low cardiac index.

Adult↗

Aortic root enlargement with glycerol-preserved homologous dura mater patch during aortic valve replacement.

Aortic root enlargement with a patch is sometimes indicated either to prevent aortic homograft valve distortion during implantation or to facilitate easy, tension-free closure of the aortotomy. Patches made of prosthetic material have been widely used for this purpose. The use of autogenous pericardium has recently been reported. Although dura mater has been shown to have great strength, low antigenicity, athrombogenicity, easy availability in large sizes and rapid bonding to most tissues, its use for patch enlargement of the aortic root has not been previously documented. From 1979 to 1983, 38 patients had dura mater aortic root gussets placed during aortic valve replacement at the Southampton General Hospital. In all cases, the patches were placed to facilitate aortic closure, or to prevent homograft valve distortion by enlarging the non-coronary sinus. Aortic homografts were implanted in 11 patients, Carpentier Edwards' Xenograft valves in 16, Björk-Shiley valves in 8 and Wessex Xenografts in 3 patients. All the patients survived and in a mean follow-up of 30 +/- 12.8 months (range 3 to 48 months) there has been no clinical evidence of patch failure due to leakage, rupture or aneurysm formation. These results suggest that glycerol-preserved dura mater is a satisfactory patch material for aortic root enlargement during aortic valve replacement.

Adolescent↗

Left ventricular aneurysm. The Wessex experience.

One hundred patients with left ventricular aneurysms were operated on between February 1973 and January 1983. The principal indications for operation were left ventricular failure in 58, angina in 23, both in 17, with arrhythmia and systemic emboli accounting for one case each. Eighty five had had anterior infarction causing 82 anteroapical and three lateral aneurysms, while the remainder had had inferior infarcts resulting in 14 inferior aneurysms and one lateral aneurysm. Coronary angiography detected a single coronary lesion in 46%. Three patients had aneurysmal plication and the remainder had aneurysmectomy. Eleven mitral valve replacements were performed. Forty patients underwent coronary artery bypass grafting with a mean number of grafts per patients of 1.4. The early mortality was 7% with no early deaths since 1978. The actuarial five year survival was 68%, and 82% of survivors are in New York Heart Association class I or II (mean follow up three years). Left ventricular aneurysmectomy may be performed with a low operative mortality and good long term results.

Coronary Artery Bypass↗

Cardiac surgery in Wessex.

The results of 3000 consecutive operations using cardio-pulmonary bypass show that the overall early mortality was 6.1%, dropping from 8.9% in the first 1000 to 4.4% in the third 1000. Operations for valve disease have been the most common, the early mortality for aortic valve replacement being 3.1% and for mitral valve replacement 2.9%. Combined aortic and mitral valve replacement had an early mortality of 4.4%. The number of patients undergoing isolated coronary artery bypass grafting has increased from 59 in the first 1000 to 292 in the third 1000 operations, with an overall early mortality of 1.3%. Six hundred and ninety seven patients underwent surgery for congenital heart disease with an overall early mortality of 10.9% (7.5% in the last 2000 cases). The patients have been followed up from one to 8.5 years. A high proportion have returned to work and enjoy a normal life. At the time of review, 87% of the 3000 patients were alive. Long waiting times for outpatient and inpatient care indicate underprovision of facilities relative to regional demand.

Adolescent↗

Valve surgery in patients over the age of sixty-five.

Two hundred one patients over the age of 65 underwent valvular heart surgery with a hospital mortality of 5.5% and a late mortality of 18.4%. One hundred forty-one patients underwent isolated valve replacement (90 AVR, 51 MVR) with a hospital mortality of 1.5% (AVR 1%, MVR 2%). Multiple procedures carried a significantly higher hospital mortality (16%). Analysis of hospital and late deaths does not suggest that age alone should be accepted as a decisive factor in selection for surgery. There is a significantly higher late mortality in those who have had MVR (30%) compared with those having had AVR (14.6%). The importance of associated coronary artery disease as a risk factor has not been defined, but there is some evidence to suggest it is more important in this respect when found in association with mitral valve rather than aortic valve disease. An improved quality of life postoperatively was evident in the majority of survivors.

Age Factors↗

Acquired ventricular septal defect.

The past 9 years' experience with ventricular septal rupture complicating myocardial infarction has been reviewed. Thirty-six patients were treated surgically, with 10 early deaths (28%) and one late death, for an 8 year actuarial survival rate of 63%. The mortality was highest for those defects which followed inferior infarction, 38% compared with 13% following anterior infarction. The infarction-operation interval also greatly influenced mortality; under 2 weeks, 43%; over 2 weeks, 18%. Concomitant coronary artery bypass grafts (13 patients) or left ventricular aneurysmectomy (14 patients) did not carry an increased mortality. Of 17 patients who presented with cardiogenic shock, eight died (47%). The intra-aortic balloon pump (IABP) was used in 16 patients (44%) and helped greatly in the management of the critically ill. With an estimated 17 acquired septal defects occurring each year in persons under 65 years of age in Wessex, awareness of this complication and of the favorable outcome of operation is essential among those who treat the aftereffects of myocardial infarction.

Aged↗

The quality of life after cardiac surgery.

A follow-up study to assess the quality of life after cardiac surgery was begun in 1973. The results, for a total of 383 patients followed up for a maximum of 44 months after surgery, showed an overall improvement in all aspects of life for most patients.

Activities of Daily Living↗

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↗

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↗