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Biomedical subjects

A J Parry

Publications and source records attributed to A J Parry.

30 records · Page 2Linked to original sources
PubMed1996

Cardiopulmonary bypass during pregnancy.

Despite the incidence of heart disease during pregnancy falling to 1.5% over the last 25 years, when a cardiac operation is required the risk is obviously greater as two lives are at risk. The risk to the mother is now similar to that for nonpregnant female patients (3% overall) but the fetal mortality remains high (19%). Cardiac operation is ill advised except in extreme emergencies during the first two trimesters as the incidence of teratogenesis is high. During the third trimester, with improvements in the outcome for premature infants with modern neonatal intensive care, delivery of the child immediately before commencing cardiopulmonary bypass is a safe option. If this is inappropriate, high-flow, high-pressure, normothermic bypass for as brief a period as possible should be used. However, although it has theoretic advantages, the benefit of pulsatile perfusion is unproven. The fetal response to cardiopulmonary bypass is bradycardia thought to be due to hypoperfusion secondary to uterine contractions, and this dysrhythmia is reversible by increasing the perfusion rate. Fetal heart rate monitoring is therefore essential to allow these manipulations. The response of the fetoplacental unit is more complex, comprising two elements: an early vasoactive response is due to prostaglandin synthesis, whereas a more profound late acidosis appears to be related to a fetal stress response. Whether these responses can be modified by changes in our approach to cardiopulmonary bypass in pregnant women remains to be proven. Finally, uterine contractions occur in response to bypass, possibly due to a dilutional effect from the stabilizing influence of progesterone. Various techniques to modify this include the administration of progesterone, beta2-agonists, and intravenous alcohol, all with some effect. Uterine monitoring is essential to allow early control of these contractions as they are associated with significant fetal loss.

Bradycardia↗
PubMed1996

Fate of the native aorta after repair of acute type A dissection: a magnetic resonance imaging study.

OBJECTIVE: To determine late patency of the aortic false lumen and propensity for aneurysm formation after repair of type A dissection. DESIGN: Retrospective follow up study. SETTING: Regional cardiac surgical unit. PATIENTS: 28 patients after repair of type A dissection. METHODS: Magnetic resonance imaging (MRI) was performed between 6 weeks and 12 months after operation. RESULTS: A patent distal false lumen with demonstrable blood flow was found in 22 patients (78%). Only six patients had complete obliteration of the false lumen by thrombus. The conduct of operation did not influence this. Nine patients (32%) showed aneurysmal dilatation of the false lumen and three had a repeat operation. CONCLUSIONS: So-called "successful repair" of aortic dissection does not obliterate the distal false lumen. MRI is a safe and effective radiological procedure for determining patency and dilatation in the false lumen. Patients with type A dissection with blood flow in the false lumen should be studied every 6 months to look for aneurysmal dilatation.

Acute Disease↗
PubMed1995

Myxoma of the aortic valve.

Myxomas are one of the most common cardiac tumors but usually are confined to the atria. Although described in all cardiac chambers and on all cardiac valves, only one postmortem case of an aortic valve myxoma has been published. We present the case of a young man with an aortic valve myxoma with peripheral embolization. The other pathologic conditions with which valvular myxomas can be confused are compared and discussed.

Adult↗
PubMed1995

Leg ischaemia following bilateral internal thoracic artery and inferior epigastric artery harvesting.

There is increasing evidence that the use of arterial conduits for coronary artery bypass grafting provides superior long-term results when compared to using saphenous veins alone. Major complications of using internal thoracic arteries (ITAs) and inferior epigastric arteries (IEAs) are uncommon. We report the case of a 42-year-old man who underwent coronary revascularisation in which harvesting of these arteries resulted in critical ischaemia of the lower limbs requiring aortobifemoral grafting. This patient had a long-standing occluded abdominal aorta which was asymptomatic and relied on the ITAs and IEAs as important collateral blood supply to the legs. The enormous size of these conduits found at operation suggested their role. Management strategies to avoid such a serious complication are discussed.

Abdominal Muscles↗
PubMed1995

Transmyocardial laser revascularization.

In transmyocardial laser revascularization a series of channels are created between the left ventricular cavity and the myocardium. The operation is usually performed in isolation via a left thoracotomy without cardiopulmonary bypass, but has been done in combination with coronary artery bypass grafting. Angina pectoris with coronary artery anatomy unsuitable for either angioplasty or bypass grafting is currently the most common indication for this procedure.

Angina Pectoris↗
PubMed1994

Heart-lung transplantation in situs inversus and chest wall deformity.

Heart-lung transplantation in the presence of complex congenital heart disease including situs inversus and significant chest wall deformity can be accomplished successfully. However, the postoperative course is apt to be prolonged because of mechanical respiratory problems, which will respond to a protocol of weaning and nutritional supplementation.

Adult↗
PubMed1994

An audit of cardiac surgery in patients aged over 70 years.

With an increasingly aged population, the number of patients requiring treatment for cardiovascular diseases will rise. Previous expectations of cardiac surgery in the over-seventies have been poor, with surgery being very much a last resort. We decided to test whether this was appropriate, and to determine whether the priority of surgery affected the outcome. Three hundred and six patients over the age of 70 were operated on in our unit in a 4 1/2-year period, 210 as elective operations and 96 as emergencies. Eighty-nine per cent were in NYHA class III-IV pre-operatively and half had other significant medical problems. Most (46%) underwent coronary artery surgery. The methods used were identical to those used for the younger patients in both operative approach and post-operative management. The overall mortality was 6.9%; 1.9% for elective procedures and 16.7% for emergencies (12.3% when catastrophic pathologies are excluded). However, the morbidity was not significantly different between the two groups and the length of post-operative ventilation and hospital stay were likewise not significantly different. Follow-up of the survivors showed no late deaths, and 87% were in NYHA class I and II. Of the others, 25 have required additional hospital admissions for associated cardiac problems. One required another invasive procedure (a PTCA), but none has required further surgery. The findings of low mortality for elective cardiac surgery in this age group are in agreement with other reports. If early referral prevents emergency surgery, it should be avidly pursued, in view of the improved outcome for elective surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Stentless aortic bioprosthesis? The way forward: early experience with the Edwards valve.

Tissue valve degeneration has been variably attributed to preservation and fixation methods. Additionally, a rigid valve ring might contribute to valve failure. The use of a nonstented porcine valve in the aortic position has clear hemodynamic advantages, and the lack of a stent may favorably influence long-term function. We have implanted stentless aortic valves (Prima valve) in 31 patients. There were 17 men. The mean age was 71.5 years (range, 50 to 83 years). After sculpturing of the sinuses the valve is positioned below the coronary arteries. Valve sizes ranged from 19 to 27 mm. There were no early or late deaths. Mean follow-up to date is 8.9 months (range, 4 weeks to 15 months). Early hemodynamic follow-up using Doppler echocardiography shows average peak systolic and mean gradients of 20.4 mm Hg and 8.6 mm Hg, respectively, at 4 weeks in 26 patients, with no significant change in 13 patients at 6 months. All patients are currently in New York Heart Association class I or II. Our early experience of stentless aortic valves shows them to be reliable with a satisfactory early hemodynamic profile. Their use in the elderly may conserve homografts for children and the young.

Aged↗
PubMed1993

Continuous retrograde cerebral perfusion during an aortic arch operation.

An 81-year-old woman presented with acute aortic regurgitation in the setting of an aneurysm of the ascending aorta and arch. The aortic valve, ascending aorta, and arch were replaced with a composite graft during continuous hypothermic total-body perfusion. Continuous cerebral perfusion was carried out by low-pressure retrograde perfusion via the superior vena cava while perfusion of the lower body was maintained via a femoral arterial cannula.

Aged↗
PubMed1992

Reoperation for prosthetic valve endocarditis in the third trimester of pregnancy.

A pregnant 29-year-old woman underwent emergency aortic valve re-replacement for prosthetic valve endocarditis. Cesarean section was performed with the chest open ready for cannulation. Fears of uterine hemorrhage during systemic heparinization for cardiopulmonary bypass were unfounded, and both mother and the 28-week-gestation newborn recovered uneventfully.

Adult↗