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Biomedical subjects

M X Shanahan

Publications and source records attributed to M X Shanahan.

At least 19 recordsLinked to original sources
PubMed1989

Repeat myocardial revascularization surgery: an analysis of 169 cases.

One hundred and sixty-nine patients who underwent repeated myocardial revascularization surgery between 1982 and 1987 were studied. The mean interval between operations was 91.6 +/- 7.3 months. The indications for repeated surgery were graft failure in 37.2% of patients, progressive coronary atherosclerosis in 40.2% of patients and a combination of the two causes in 22.5% of patients. The mean number of grafts that were inserted was 2.74 +/- 0.61 grafts per patient at the second operation. Coronary endarterectomy as an adjunctive procedure was necessary in 17.1% of patients. The hospital mortality rate was 4.1%, with a 1.8% incidence of perioperative myocardial infarctions. Of the surviving patients, 96.3% were available for follow-up at a mean of 19 +/- 6.4 months. Of these patients, 68.5% were well and could be categorized into the New York Heart Association's functional class I. We conclude that both progression of coronary atherosclerosis in native vessels and obstruction of venous grafts cause recurrent angina and that repeated myocardial revascularization surgery is a feasible treatment option in these patients.

Adult↗
PubMed1989

Ascending aortic aneurysms associated with aortic valve regurgitation: St Vincent's Hospital's experience.

This report represents a retrospective analysis of the St Vincent's Hospital experience with combined replacement of the aortic valve and ascending aorta using a composite conduit and coronary artery reimplantation, in 44 patients, from 1 January 1981 to 30 June 1988. The mean age at operation was 48 years. Annuloaortic ectasia was the most common indication for operation in 24 patients (54%). There were three hospital deaths (7%). Forty-one patients were discharged from hospital and were followed up for a total of 1,106 patient months (mean = 26.5 months). There were three late deaths (7%). One death was due to a new dissection, one to a cerebrovascular accident and one to a drug overdose. So far, no patients have required reoperation. Of the 36 surviving patients available for follow-up, 28 are in New York Heart Association class I, seven patients are in class II and one in class III. Composite graft replacement reduces the risk of recurrent dissection and aneurysm formation and of periprosthetic leak. In the present experience, it is the method of choice in patients with degenerative lesions in the ascending aorta and aortic valve and particularly for annuloaortic ectasia. The exact surgical technique currently used has been the result of an evolution of different techniques.

Adolescent↗
PubMed1989

Open cardiac compression in the postoperative cardiac intensive care unit.

Thirty-nine patients required heroic resuscitative measures for sudden hypotension and cardiac arrest in the first 72 hours following cardiac surgery between January 1, 1984 and May 31, 1988. Emergency sternotomy with open cardiac compression was performed in twenty-four of these patients when external cardiac compression failed. These were categorised as Group A. Group B comprised the fifteen patients in whom resuscitation was entirely by means of external compression and adjuvant measures. Survival with NYHA Functional Class I and II status was noted in 75% of patients in Group A, compared with 20% in Group B (P less than 0.002). Emergency sternotomy with open cardiac compression is an effective way of resuscitating patients in the intensive care unit in the first few days following open heart surgery.

Cardiac Surgical Procedures↗
PubMed1988

Psychological adjustment after cardiac transplantation.

Cardiac transplantation is viable therapeutic alternative for patients with end-stage heart disease, which offers a favourable short- and medium-term prognosis. The survival has improved from 20% of patients who survived at one year after transplantation in the 1960s to the present figures of 80%-85% of patients who are alive at one year, and 50%-70% of patients who are alive at five years, after transplantation. Therefore, it seems timely to focus attention on the psychological well-being of cardiac-transplant recipients. The medical literature is scant in regard to the psychiatric and the psychosocial impact of cardiac transplantation on recipients, and a systematic and prospective study of the psychosocial adaptation of recipients is lacking. Since 1984, we have been studying the emotional impact of cardiac transplantation on recipients and their families. This article presents the results for a group of recipients who have been assessed before transplantation, then followed-up at discharge from hospital and at four, eight and 12 months after transplantation. The study attempted to quantitate the recipients' anxiety, depression, body image and subjective quality of life by way of standardized self-assessment questionnaires. The recipients' satisfaction with relationships or their marital situation also was reported, as were their degree of rehabilitation at 12 months and their attitudes to various aspects of treatment after the transplantation. Before the transplantation, 53% of patients reported an increase in anxiety and 34% of patients recorded scores that indicated mild-to-moderate levels of depression. Thirty-seven per cent of patients showed a deterioration in the quality of their lives and 34% of patients had a negative body image. After the transplantation, significant improvements occurred in all parameters, which were maintained at follow-up.

Adaptation, Psychological↗
PubMed1987

Effects of low-dose cyclosporine A on toxicity and rejection in cardiac transplantation.

In conclusion, the low doses of CsA have significantly reduced nephrotoxicity and infectious complications. The patient survival has been acceptable, but there has been a disappointing incidence of rejection and graft loss in patients who have survived the first 3 months. We feel our experience would indicate that by targeting our CsA dosages to such low serum levels some of our patients receive suboptimal immunosuppression. Perhaps the best way of overcoming this is add a third maintenance immunosuppressive agent such as azathioprine to supplement immunosuppression. In fact, we have now changed our immunosuppressive protocol to include azathioprine while maintaining our CsA therapy at its current level.

Adolescent↗
PubMed1986

Rationale for simultaneous carotid endarterectomy and aortocoronary bypass.

Seventy-eight patients were treated for coexistent carotid and coronary stenosis by simultaneous reconstructions. Five patients died (6.4%), one from a stroke contralateral to the carotid reconstruction. Four others suffered a perioperative stroke (total stroke incidence 6.4%). Three myocardial infarctions occurred (3.8%) including one fatal infarct. Analysis of the most recent 36 combined reconstructions indicates that the extramorbidity in this group increased the stroke or death rate for all carotid endarterectomies carried out in the same period by only 1%. Alternatively if these patients had been operated upon by aortocoronary grafting alone the mortality would have increased by 0.1% assuming no neurologic complications. Since these 36 patients had severe carotid stenosis and would have been refused carotid endarterectomy as an isolated procedure the results seem better than would have been achieved by staged operations.

Adult↗
PubMed1985

Combined carotid coronary reconstructions--synchronous or sequential?

Analysis of 16 synchronous with 26 sequential combined carotid coronary reconstructions showed no statistical advantage of either approach. Sequential operations are more convenient but increase the total operating time by an hour or so. Synchronous operations can be carried out without carotid shunting despite hypotension provided hypothermia is established. In other circumstances the internal carotid back pressure is used to indicate the need for carotid shunting. In the 42 patients there were three strokes (7%) including one fatal stroke (2%) and two myocardial infarctions, both fatal (5%).

Cardiopulmonary Bypass↗
PubMed1985

Patient selection for cardiac transplantation.

Since February 1984, 27 isotopic cardiac transplants have been performed in 25 patients. These 25 patients were from a pool of 45 patients who were accepted into the Programme. Sixteen patients have died awaiting a transplant, and four patients are presently on the waiting list. All patients accepted for cardiac transplantation were NYHA Class IV. There were 136 referrals during this period for cardiac transplantation, and 14 referrals for heart-lung transplantation. The commonest reason for non-acceptance into the Programme is that patients were considered not to be ill enough and to have a prognosis of more than six months. Patient selection is a key factor in ensuring a successful outcome with cardiac transplantation.

Adolescent↗
PubMed1983

Long-term results of tricuspid valve replacement and the problem of prosthetic valve thrombosis.

Observations in 71 patients having tricuspid valve replacement over a 14-year period are described. The operative mortality rate was 10% and the actuarial survival rate was 73% at 5 years and 47% at 10 years. Survival was unaffected by the number of valves replaced or the type used (27 Starr-Edwards, 32 Björk-Shiley, 8 Lillehei-Kaster, and 4 porcine xenografts). Complications were common: 3 deaths were related to anticoagulation and 1 was due to a systemic embolus. Six patients required permanent pacing. There was a very high incidence of thrombosis of the prosthetic tricuspid valve. Twenty percent of the tilting disc valves thrombosed, compared with 4% of the Starr-Edwards valves (p less than 0.05). Symptoms of thrombosis were usually insidious, and its diagnosis was often delayed. There was a continuing risk of this complication, and presentation occurred up to 12 years after the original operation. Thrombolytic therapy with streptokinase was successful in 1 of 2 patients. Replacement of the thrombosed prosthetic valves was carried out without mortality in 8 patients.

Adult↗
PubMed1982

Postinfarction cardiac rupture.

This paper records an experience of 42 cases of cardiac rupture or syndromes simulating rupture. These include free wall rupture, hemopericardium without rupture, septal rupture associated with free wall rupture, pseudoaneurysm, and septal rupture. These groups constitute a series of syndromes with many features in common in terms of clinical presentation, difficulty in assessment, timing of operative intervention, and operative management. Free wall rupture, which can be simulated by hemopericardium without rupture, is not always rapidly fatal. Successful intervention was achieved in six of the 13 cases in the free wall group. Ventricular septal defect occurs less frequently than free wall rupture, is more easily diagnosed, and less frequently requires urgent medical intervention. In 12 of the 14 cases of acute rupture, stabilization of the patient by conservative measures could not be achieved and operation was undertaken within 1 week of infarction. There were seven survivors, in four of whom the defect reopened, with successful reoperation in three. In the remaining 15 cases, stabilization by conservative measures was achieved and operation was delayed until at least 2 weeks after infarction. There were 14 survivors and only one instance of reopening of the defect.

Aged↗
PubMed1980

Endocarditis due to an atypical mycobacterium following porcine heart valve replacement.

Following aortic valve replacement with a porcine xenograph, a patient developed endocarditis complicated by a fistula between aorta and right ventricle. The xenograph was replaced by a mechanical valve and the fisutla oversewn. No organisms were cultured but acid-fast bacilli were seen in the aortic wall and excised valve tissue. It is likely that these were contaminants of the porcine prosthesis.

Aortic Valve↗
PubMed1979

Cardiac valve replacement (1963-1979).

A 15-year experience (from 1963-1978) in cardiac valve replacements with mechanical prosthetic valves (caged ball or tilting disc types) and with bioprostheses (porcine xenografts) is reported. The actuarial survival rates for patients who received the caged ball type prostheses (Starr-Edwards) were 42% and 36% respectively for mitral valve-replacements at 12 and 14 years. The actuarial survival rate for patients who received the tilting disc type prostheses (Björk-Shiley type and later the Lillehei-Kaster type) was 74% at six to seven years. The actuarial survival rate for patients who had aortic valve replacement with a caged ball valve was 43% at 14 years, and for those who had a tilting disc valve it was 80% at six to seven years. Multiple valve replacements were carried out with combinations of prostheses. The actuarial survival rate for patients was 65% for triple valves, and 57% for double valves at 13 years. Bioprostheses are now our first choice as cardiac valve replacements. In 121 implants performed since 1977, there have been two operative deaths, but no late deaths. Bioprostheses, although less thrombogenic than mechanical valve prostheses, are less durable and some risk of thromboembolism remains.

Adolescent↗
PubMed1978

Perforation of the interventricular septum complicating myocardial infarction.

The presentation and management of 21 patients with postinfarction ventricular septal defect (VSD) in whom surgical treatment was considered or performed since 1970 have been analysed and reviewed. An acute group of 11 patients, each of whom developed cardiogenic shock, 9 of whom came to surgery within one week from the onset of their VSD, had a poor outlook, only 27% becoming long-term survivors. Six patients were classified as subacute because their surgery was precipitated by worsening congestive cardiac failure in all, and by pulmonary oedema at the time of surgery in three patients. Four chronic patients were operated upon electively. The results in the subacute and chronic groups were excellent, and all are long-term survivors. Operative closure of the defect is best achieved by the use of a patch. Infarctectomy and aneurysmectomy are necessary in more than half of the cases. Left ventricular assistance by the intra-aortic balloon counterpulsation catheter has been disappointing and did not contribute to long-term survival. The major factor determining survival is the integrity of the closure, and the function of the remaining viable myocardium. Reoperation for reopening of the defect should always be considered.

Acute Disease↗
PubMed1978

Calcification of the mitral annulus.

Successful valve replacement has been achieved within the first three years in two patients who had extensive calcification of the mitral valve annulus. This condition, although commonly reported in pathology and autopsy studies, has been rare in our clinical experience. Surgical management does not appear to us to have been reported previously. It was regarded in our earlier experience as a deterrent to mitral valve surgery. Certain technical factors which contributed to success are emphasized in the two cases described in this report.

Calcinosis↗