Biomedical subjects

D F Shore

Publications and source records attributed to D F Shore.

At least 37 records · Page 2Linked to original sources

PubMed1993

Brain damage after profoundly hypothermic circulatory arrest: correlations between neurophysiologic and neuropathologic findings. An experimental study in vertebrates.

Five groups of neonatal pigs were subjected to cardiopulmonary bypass with circulatory arrest periods that varied from 70 to 120 minutes for the investigation of brain changes in induced deep-core hypothermia (15 degrees C) with circulatory arrest. The parameters that were analyzed were (1) microscopy of the brain in animals at 6 hours after bypass procedures and (2) intraoperative monitoring of somatosensory evoked potentials. Microscopic cellular damage appeared in all animals with a circulatory arrest period of more than 70 minutes. These changes involved mainly Purkinje's cells of the cerebellum, and they affected particularly the inferior half of the cerebellum. The prolongation of latency in the cortical responses, which reflects a slowing of the neural transmission with hypothermia, occurred in all animals. The late evoked potentials remained absent in all piglets with circulatory arrest periods of 90, 105, and 120 minutes, but they were fully recovered in all piglets of the control group and those with 70-minute arrest times. We concluded that the cerebellar region is the most sensitive site in which ischemic lesions attain their maximal severity and extent, and the maximum time of circulatory arrest without histopathologic and neurophysiologic sequelae should not exceed 70 minutes.

Animals↗

PubMed1992

Twelve year experience with the modified Blalock-Taussig shunt in neonates.

Between 1978 and 1990, 53 consecutive modified Blalock-Taussig (MBT) shunts were performed on 51 neonates with cyanotic congenital heart disease using 3 mm-5 mm Gore-Tex grafts. Only 4 of these children had uncomplicated tetralogy of Fallot. The remainder had more complicated pathology requiring urgent intervention. Retrospective analysis of the acute and long term results was performed with 100% follow-up, ranging from 1 month to 12 years (mean 3 years). There were 3 (6%) early deaths (within 30 days of operation) and 17 (33%) late deaths. Of the late deaths, 2 died after further palliation, 2 died after total correction and 13 died suddenly at home. Post mortem examination of the 13 sudden deaths revealed blocked shunts in only 3. Actuarial survival at 2 years was 58%. Shunt patency at 12 months was 87% and at 2 years, 62%. No patient used their initial MBT shunt for more than 40 months. Although this shunt provides good initial palliation, there is a high incidence of late sudden death. We are also concerned about the limited life span of the shunt which partly (3/13) explains the sudden deaths. Therefore we have adopted an aggressive approach to re-study by angiography within 3 months of surgery.

Actuarial Analysis↗

PubMed1991

Cardiac arrhythmias after surgical correction of total anomalous pulmonary venous connection: late follow-up.

Sixteen patients (10 males and six females) aged 7 months to 20 years, who had undergone surgical repair in the first year of life for total anomalous pulmonary venous connection (TAPVC), underwent assessment of cardiac rhythm by 24-h electrocardiogram (ECG) monitoring, nine of them also had maximal exercise treadmill tests, 3 months to 19.5 years after surgical repair. No patient had symptoms of an arrhythmia and the resting ECG was normal in all except one who had occasional single supraventricular ectopic beats. But on 24-h ECG monitoring significant arrhythmias were recorded in six of the 16 patients, including supraventricular tachycardia (three patients), bradyarrhythmia (two patients), sick sinus syndrome (two patients), and multiform supraventricular and ventricular ectopic beats (two patients). Five of these six patients were assessed more than 6 years after surgery. An inappropriate chronotropic response was seen on maximal exercise treadmill testing in four patients; three of them had arrhythmias previously recorded by 24-h ECG monitoring. Our observations show that significant arrhythmias may occur in asymptomatic patients long after TAPVC correction, and we therefore recommend long-term follow-up of these patients, even if they are asymptomatic.

Adolescent↗

PubMed1991

The early and long-term results of surgery for coarctation of the aorta in the 1st year of life.

The cases of 110 infants less than 1 year of age, who had surgical repair for coarctation of the aorta between June 1974 and February 1988, were analysed. Three groups of patients were identified. In group 1 there were 39 patients with isolated coarctation. In group 2 there were 25 infants with additional ventricular septal defects (VSD), while in group 3 there were 46 infants with other associated congenital cardiac defects. Repair was performed using the subclavian flap aortoplasty (SFA) procedure in 83 patients, resection with end-to-end anastomosis (EEA) in 23, patch aortoplasty in 3 and Goretex tube bypass in 1. Twenty-eight patients had simultaneous pulmonary artery banding and one concomitant closure of the VSD. The overall early mortality rate was 8.2% (5.1% in group 1, 0% in group 2, and 15.2% in group 3). Age at operation (under 1 month, p = 0.04) and other associated cardiac anomalies (p = 0.03) increased early mortality significantly. There were 11 late deaths (10.8%) among 101 patients followed from 1 to 15 years (mean 5.3 years). Twelve patients underwent further surgery for recoarctation, eight of them within 11 months. A further 11 patients currently have a Doppler gradient across their coarctation site of more than 20 mmHg, but have not undergone further surgery to the coarctation repair site.

Anastomosis, Surgical↗

PubMed1990

Reoperation for recurrent angina after aortocoronary bypass surgery.

One hundred reoperations were performed on 93 patients of a total of 2287 patients who underwent initial coronary artery bypass surgery (CABG) between September 1972 and August 1988. The mean age of the 84 males and 9 females was 55.5 years (range 31-75 years). All patients prior to reoperation had severe angina and were judged to be in NYHA class III or class IV. Late graft failure alone or in combination with progressive atherosclerosis accounted for more than 60% of the cases requiring reoperation. The early mortality for reoperation was 1% compared with 1.4% for initial CABG. Perioperative myocardial infarction was recorded as a complication in 3.2% of cases at initial operation compared with 1% at reoperation. Symptomatic improvement occurred in 89.1% of cases after reoperation and almost 60% became entirely asymptomatic (mean follow-up interval 17 months).

Adult↗

PubMed1990

Gamna-Gandy nodules in a cardiac myxoma.

A 33-year-old female was admitted for surgery for removal of a left atrial myxoma. Histological examination of the tumour showed features characteristic of myxoma. Additionally, Gamna-Gandy bodies were present in the tumour. This is a rare finding.

Adult↗

PubMed1990

Changing role of non-invasive investigation in the preoperative assessment of congenital heart disease: a nine year experience.

The total surgical experience of a supraregional paediatric cardiology unit over a nine year period (January 1980 to December 1988) was reviewed to assess the effect of the introduction of the full range of ultrasound techniques. A total of 1517 patients underwent cardiac surgery (955 cardiopulmonary bypass, 562 closed procedures). Of these, 485 patients (32%) did not undergo cardiac catheterisation before operation: 217 bypass (23% of all procedures under cardiopulmonary bypass) and 268 closed procedures (48%). The overall ratio of catheterisations to operations for patients undergoing palliative or corrective surgery fell from 0.97 (1980) to 0.38 (1988). The patients were classified as (a) neonates (0-28 days), (b) infants (one to 12 months), and (c) children (one to 14 years). The main impact of non-invasive surgical referral was in neonates (total catheter:operation ratio 0.38; neonates 0.2 for 1988). The surgical population was further divided according to the principal echocardiographic technique available: (a) 1980-4 cross sectional imaging; (b) 1985-6; imaging plus spectral Doppler ultrasound; (c) 1987-8; imaging plus spectral Doppler ultrasound and colour flow mapping. A fall in the catheter:operation ratio for all age groups was most pronounced in the last four years. This reflects increased familiarity and surgical confidence with non-invasive diagnostic assessment. The introduction of each new echocardiographic technique was associated with a significant fall in the total catheter:operation ratio compared with the preceding period. Six incorrect ultrasound diagnoses were made during the entire period; one of these patients died in the early postoperative period. The integration of Doppler ultrasound with cross sectional imaging has made non-invasive assessment an increasingly practical alternative to preoperative cardiac catheterization.

Adolescent↗

PubMed1990

Primary balloon dilatation of coarctation of the aorta in neonates.

Primary balloon dilatation of coarctation of the aorta was attempted in 10 consecutive neonates (age range 2-23 days). The coarctation site was crossed and the balloon inflated in all but one patient. In two patients with associated severe isthmal hypoplasia there was no change in the gradient after dilatation. In the remainder, the residual gradients were trivial and angiography showed complete relief of coarctation. Severe recoarctation developed 5-12 weeks after dilatation in five patients, each considered to have had an excellent initial result. The coarctation was rapidly progressive in three patients in whom Doppler studies within two weeks of the development of recoarctation had shown no significant gradient. In the other two patients progressive restenosis was charted by Doppler examinations over the course of 6-8 weeks. Three patients had a second, initially successful, dilatation procedure. One patient remained well with no residual gradient 18 weeks later. Stenosis recurred within eight weeks in the other two, and both have undergone successful surgical repair. Balloon dilatation of a native coarctation of the aorta gave excellent immediate results in most neonates. Severe isthmal hypoplasia is, however, a contraindication to balloon dilatation and early restenosis is an important problem. These results do not support the continued use of primary balloon dilatation of coarctation of the aorta in neonates.

Aorta, Thoracic↗

PubMed1990

Surgical treatment for infarct-related ventricular septal defects. Improved early results combined with analysis of late functional status.

A total of 101 patients (mean age 64.9 years) underwent surgical correction of postinfarction ventricular septal defect at this institution over a 15-year period (1973 to 1988). The overall early mortality rate was 20.8%, although the most recent experience with 36 patients (January 1987 to October 1988) has seen this decline to 11.1%. Factors found to influence early death significantly, when analyzed univariately, were as follows: (1) site of infarction (anterior 12.1%, inferior 32.6%, p = 0.02); (2) time interval between infarction and operation (less than 1 week 34.1%, greater than 1 week 10.5%, p = 0.008); (3) cardiogenic shock (present 38.1%, absent 8.5%, p = 0.001). Nonsignificant variables included preoperative renal function, age, and concomitant coronary artery bypass, although older age (greater than 65 years) became significant when examined in a multivariate fashion. Of the 80 hospital survivors, eight were subsequently found to have a recurrent or residual defect necessitating reoperation, with survival in seven. Late follow-up is 99% complete and reveals an actuarial survival rate for 100 patients of 71.1% at 5 years (95% confidence interval 60.6 to 80.0), and 40.0% at 10 years (95% confidence interval 21.7 to 58.4). A significant recent change in policy of not using coronary angiography in patients with a ventricular septal defect caused by anterior wall infarction has not resulted in any increase in either the early mortality or in the late prevalence of angina. The functional status of 38 surviving patients has been analyzed by a graded treadmill exercise protocol, whereas left ventricular functional assessment was by nuclear scan with additional information on mitral valve function by echocardiogram. Color Doppler flow mapping has been used to determine the presence of a residual defect. Most late survivors have limited exercise tolerance related to both cardiac and noncardiac factors. Left ventricular function is moderately impaired (mean ejection fraction = 0.39). However, many patients are elderly and have adapted to their residual symptoms without significant changes in life-style.

Age Factors↗

PubMed1989

Aortic valvotomy for critical aortic stenosis in neonates and infants aged less than one year.

Between April 1974 and December 1987, 20 infants (six under one month of age) (mean weight 4.9 kg) underwent surgical valvotomy for critical aortic stenosis. Three of the four patients treated before 1976 died. Since 1979, 16 infants (four neonates) have undergone valvotomy with no deaths. Mortality for the whole group was 15%; in the neonates it was 33%. There were no late deaths. The survivors were followed up for a mean of 3 years 9 months and two required re-operations. The considerable improvement in surgical results in the past decade should be taken into account when newer techniques such as balloon dilatation are evaluated.

Aortic Valve↗

PubMed1987

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↗

PubMed1985

Atrioventricular septal defect with a well developed primary component of the atrial septum ("septum primum").

A heart is described with an atrioventricular septal defect in which the lower part of the atrial septum ("septum primum") was well developed and in which superior and inferior bridging leaflets were attached neither to the crest of the ventricular septum nor the inferior rim of the atrial septum. Diagnostic pre-operative angiographic and echocardiographic features and the method of surgical correction are outlined.

Down Syndrome↗

PubMed1985

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↗

PubMed1985

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↗

PubMed1984

Calcification of implanted xenograft pericardium. Influence of site and function.

In a series of 23 dogs, glutaraldehyde-fixed xenograft pericardium was implanted as a left atrial wall patch (Group I, 11 dogs), as a substitute for the mitral valve chordae (Group II, 12 dogs), and as an external pericardial patch (Group III, five dogs, in which one of the two former procedures was associated). All dogs of Group I survived and were put to death after 12 months. The atrial patch appeared thickened and shrunken in all, with intense fibrous reaction, calcification, and even bone formation. The structural changes were minimal in the external aspect of the patch, not in contact with the host's endocardium and blood. Eight dogs of Group II survived from 7 months to 3 years. In all, the pericardial chordae were thickened and calcified with good healing at the suture lines; that their original length was retained, however, allowed for good valve function. In the dogs of Group III the pericardial substitute appeared well preserved after 12 months, not calcified, and without noteworthy degenerative changes. Minimal or absent epicardial adhesions were noted. We conclude that (1) the tendency for xenograft pericardial tissue to calcify is strongly influenced by the site of implantation and function and by contact with host blood and endocardium; (2) heterologous pericardium may be considered suitable for closure of pericardial defects after open cardiac operations, and (3) studies on calcification of biological tissue should be carried out by long-term evaluation of such tissues inside the heart.

Animals↗

PubMed1983

Aortopulmonary septal defect coexisting with ventricular septal defect and pulmonary atresia.

Three patients are described in whom an aortopulmonary septal defect (aortopulmonary window) coexisted with a ventricular septal defect and pulmonary atresia. One patient had mild and another, moderate aortic regurgitation. In addition, one patient had a sinus of Valsalva aortic aneurysm, while another had a single coronary artery arising from the pulmonary trunk. One patient underwent surgical correction in infancy; the other two, in early adult life. In all three patients, surgical correction involved closure of the aortopulmonary window, closure of the ventricular septal defect, and placement of a valved conduit between the right ventricle and the distal pulmonary trunk. One patient died 3 weeks postoperatively due to secondary hemorrhage where the conduit had been sutured to the right ventricle. The other two patients are alive and well 3 1/2 years and 6 months after surgery, respectively. The presence of aortopulmonary window permits normal development of the pulmonary arteries in the presence of the coexisting pulmonary atresia; in the three patients described, the absence of pulmonary vascular disease made total surgical repair feasible for this combination of defects.

Adult↗

PubMed1982

Recognition of imperforate atrioventricular valves by two dimensional echocardiography.

The majority of hearts in which selective right or left atrial angiography shows no direct communication between one atrium and a ventricular chamber are considered to be examples of atresia of the right or left atrioventricular valves. Most patients presenting with the clinical features of tricuspid atresia have an absent right atrioventricular connection, while those with features of mitral atresia and a normal aortic root frequently have an absent left atrioventricular connection. By studying 67 patients using two dimensional echocardiography we have identified 12 in whom there was an imperforate atrioventricular valve and not an absent atrioventricular connection. Thus, in 44 hearts with the angiographic features of tricuspid atresia, 36 had absence of the right atrioventricular connection and six had an imperforate right atrioventricular valve. In the latter, four were examples of atrioventricular concordance and two were univentricular hearts of left ventricular morphology in which the mode of atrioventricular connection was through one perforate and one imperforate valve. Similarly, 17 out of 23 cases of mitral atresia had absence of the left atrioventricular connection. The remaining six had an imperforate left atrioventricular valve which was associated with atrioventricular concordance in two patients and with double inlet univentricular heats in four patients.

Child↗

PubMed1982

Severe tricuspid stenosis presenting as tricuspid atresia. Echocargraphic diagnosis and surgical management.

Two cases of pulmonary atresia with intact ventricular septum and severe tricuspid stenosis are described in which the initial angiographic diagnosis was tricuspid atresia and pulmonary atresia. Two dimensional echocardiography showed the features of an imperforate tricuspid valve because in each case contrast echocardiography failed to show anterograde flow from the right atrium to right ventricle. Successful radical surgical repair was achieved in one patient with performing a tricuspid valvotomy and inserting an external valved conduit between the hypoplastic right ventricle and the main pulmonary artery. In the second case, an infant died four weeks after tricuspid valvotomy and right ventricular outflow tract reconstruction.

Child, Preschool↗