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Biomedical subjects

W G Williams

Publications and source records attributed to W G Williams.

At least 163 records · Page 9Linked to original sources
PubMed1989

Course of tricuspid atresia in the Fontan era.

Tricuspid atresia is an uncommon form of congenital heart disease and long-term survival was rare before the Fontan era. It was thought that the long-term survival of patients with tricuspid atresia would be improved by the introduction of the Fontan procedure and its subsequent modifications. This study reviews the clinical course of 84 patients with tricuspid atresia identified in the first year of life in the Fontan era. Prior palliative operations, their results and their ultimate application for the Fontan procedure were considered. Eleven patients died before surgical intervention and 5 did not undergo catheterization or echocardiographic confirmation before death. Five children underwent the Fontan procedure without prior palliation and 1 child does not require palliation at the present time. Sixty-seven patients (80%) had surgical procedures before evaluation for the suitability of a Fontan operation. Thirty-four patients had a second surgical palliation and 9 patients had a third palliation. The surgical mortalities for the first, second and third palliative surgery were 17.9, 17.6 and 0%, respectively. Thirty-two patients (38%) underwent the Fontan procedure and 2 deaths occurred (6%). An estimate of the probability of surviving for 1 year was 64% (95% confidence limits 54 to 74%) and that of 8 years was 55% (95% confidence limits 44 to 66%).

Blood Vessel Prosthesis↗
PubMed1989

Long-term results in neonates with pulmonary atresia and intact ventricular septum.

Our entire institutional experience with pulmonary atresia and intact ventricular septum (1965 through 1987) included 115 patients, 16 of whom died before surgical intervention. Fifty-six percent of surgical patients (n = 99) had angiographic evidence of right ventricle-coronary arterial connections. The early mortality in the surgical group was 27.2%, and the actuarial survival was 24.7% +/- 6% at 13 years postoperatively. Multivariate analysis indicated that the presence of ventriculocoronary connections (p = 0.037), a decreasing ratio between right ventricular and left ventricular pressure at the initial cardiac catheterization (p = 0.007), and lower weight at operation (p = 0.001) were incremental risk factors for postoperative death; the presence of Ebstein's anomaly was an additional risk factor in the overall experience (including patients not surgically treated) (p = 0.01). Nearly all long-term survivors underwent at least one reoperation, including right ventricular outflow tract reconstruction (n = 39) and thromboexclusion of the right ventricle (n = 9). The presence of severe stenosis or interruption of the proximal left anterior descending coronary artery system was a uniformly lethal risk factor for patients undergoing these procedures (p = 0.0003). We conclude that surgical procedures that successfully decompress the right ventricle will usually result in biventricular circulation in and long-term survival of patients with pulmonary atresia with intact ventricular septum not complicated by Ebstein's anomaly or extensive ventriculocoronary connections. Decompression or thromboexclusion of the right ventricle is contraindicated in patients with ventriculocoronary connections and a right ventricle-dependent coronary circulation.

Coronary Vessel Anomalies↗
PubMed1989

Effect of oxygen tension on the anti-oxidant enzyme activities of tetralogy of Fallot ventricular myocytes.

Since the chronically cyanotic tetralogy of Fallot (TOF) myocardium is more sensitive to reperfusion injury after cardiac surgery than the adult myocardium, we decided to study the regulation of myocardial superoxide dismutase (SOD), catalase and glutathione peroxidase by oxygen tension. TOF myocytes were cultured at a Po2 of 150 mmHg for 30 days to establish the culture. The cells were then cultured at Po2 of 150 and 40 mmHg and the myocyte antioxidant enzymes measured at days 3, 7, 14 and 21. On day 21 the myocytes cultured at Po2 of 40 mmHg were then cultured at 150 mmHg and SOD and catalase activities measured on days 28 and 35. Although there were no differences in the rates of incorporation of 35S-methionine into the myocytes at either Po2 on these days, the myocytes scavenger enzyme levels were significantly higher by day 14 when cultured at a Po2 of 150 mmHg than at a Po2 of 40 mmHg. With the increase in oxygen tension from 40 to 150 mmHg, SOD and catalase activities increased significantly by day 35. The myocytes cultured at Po2 40 mmHg were more sensitive by day 7 to an hypoxanthine-xanthine oxidase generated free radical injury than the Po2 150 mmHg cultured cells. The regulation of these enzyme activities by oxygen tension and the increased sensitivity to free radical injury of the myocytes cultured at an oxygen tension of 40 mmHg provide putative evidence that the chronically cyanotic myocardium may be less well protected than the normally perfused myocardium against oxygen-mediated free radical injury and be at higher risk for cardiovascular surgery.

Catalase↗
PubMed1989

Analysis of survival in patients with pulmonary atresia and intact ventricular septum treated surgically.

The epidemiology of 98 children who underwent surgical intervention for pulmonary atresia and intact ventricular septum is presented. Sixty-one (62.2%) of the children died. Survival time from the date of the first operation ranged from 0 to 17.76 years. Analysis of the survivors revealed that an estimate of the probability of surviving for two years is 47% (95% confidence limits of 37%, 57%). An estimate of the median survival time is 1.43 years. In a Cox proportional hazards model, using survival time in days as the outcome variable (n = 73, using complete data), operative weight at first operation (P = 0.0019), right/left ventricular pressure ratio (P = 0.0185), and absence of ventriculo-coronary arterial connections (P = 0.0362) were identified as significant predictors of survival.

Adolescent↗
PubMed1989

Aortic regurgitation: a common complication after surgery for hypertrophic obstructive cardiomyopathy.

Surgical ventriculomyectomy and ventriculomyotomy by the aortic approach are safe and effective methods of relieving symptoms and obstruction to left ventricular outflow in patients with hypertrophic obstructive cardiomyopathy. With the addition of Doppler ultrasound to the routine follow-up assessment of these patients an unexpectedly high occurrence of aortic regurgitation was found in the postoperative patients. Because aortic regurgitation has been reported to rarely accompany this condition, 67 patients with hypertrophic obstructive cardiomyopathy were studied clinically and with Doppler echocardiography for the presence and severity of aortic regurgitation. Severity of the regurgitation was quantitated by pulsed or color Doppler echocardiography according to the length and width of the regurgitant jet in at least two views. In 37 patients with hypertrophic obstructive cardiomyopathy who did not undergo surgery, aortic regurgitation was detected in only 1 (3%) by Doppler ultrasound and in none clinically. In 52 patients who did undergo surgery and were studied a mean of 7.8 years postoperatively, aortic regurgitation of trivial to moderate degree was common, being detected in 28 (54%) by Doppler ultrasound and in 6 (12%) clinically. In a subgroup of 22 patients who were studied preoperatively and again early postoperatively (mean 6 weeks), new aortic regurgitation was found in 8 (36%) and was graded as trivial in all. Aortic regurgitation is a common complication related to ventriculomyectomy and ventriculomyotomy in patients with hypertrophic obstructive cardiomyopathy. Although initially trivial, the regurgitation may progress in severity over time. The regurgitation has been well tolerated in all patients studied to date.

Aortic Valve↗
PubMed1989

Surgical experience with left ventricular outflow tract obstruction in patients with complete transposition of the great arteries and essentially intact ventricular septum undergoing the Mustard operation.

During a 24-year period (1963-1987), 46 infants and children with complete transposition of the great arteries (CTGA) and an essentially intact ventricular septum (IVS) have undergone surgical relief of left ventricular outflow tract obstruction (LVOTO) concurrently with the Mustard operation (MO). The obstruction was valvar in 2 patients, subvalvar in 43 and combined valvar and subvalvar in 1; the ventricular septum was intact in 42, and 4 patients had a small VSD at the time of repair. Neonatal and pre-Mustard cardiac catheterization (CC) data were analyzed to obtain LV to right ventricular peak systolic pressure ratio (LV/RVPSP) and LVOT peak systolic gradient (PSG). The mean neonatal LV/RVPSP (n = 31) was 0.79 +/- 0.04; pre-Mustard LV/RVPSP (n = 44) was 0.75 +/- 0.05; pre-Mustard LVOT PSG (n = 34) was 46.5 +/- 3.5 mmHg. Neonatal (n = 29) and pre-Mustard (n = 30) cardiac angiograms were retrospectively reviewed to analyse morphologic substrates of LVOTO. In the neonatal period, LVOTO was present in 7 patients (anatomic, n = 4; dynamic, n = 2; combined, n = 1). Immediately prior to the MO, LVOTO was present in 29 (anatomic, n = 20; dynamic n = 2; combined, n = 7). Techniques to correct LVOTO at the initial MO included pulmonary valvotomy (n = 3), ventriculomyectomy (n = 41), resection of an windsock aneurysm (n = 1), LV to pulmonary artery valved conduit (VC) (n = 1). Two patients underwent VC early postoperatively (PO) for severe residual LVOTO (both died).(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1989

Fibrinolytic treatment of acute prosthetic heart valve thrombosis. 5 cases and a review.

Acute thrombotic obstruction of prosthetic heart valves has usually needed an emergency operation and carries a high mortality. Over the past 16 years, sporadic papers have appeared reporting the successful use of fibrinolytic therapy with a low mortality. We report five consecutive cases treated in this way. The diagnosis of valve thrombosis was made on clinical, echocardiographic and cineradiographic grounds. Treatment consisted of streptokinase (SPK) in a loading dose of 250,000 units in one case and 500,000 units in the remaining four cases, followed by 100,000 units hourly. Rapid improvement in clinical state was seen in all five patients. Four patients recovered completely and have been followed up for a minimum of 3 years. One patient died of a retroperitoneal haemorrhage, a recognised complication of fibrinolytic therapy. A review of the literature is presented. Fibrinolytic therapy is recommended in the acute episode and should result in either a return to normal valve function or sufficient improvement in haemodynamics to allow semielective surgery at considerably lower risk.

Adult↗
PubMed1989

Abnormal cardiac signs after Fontan type of operation: indicators of residua and sequelae.

Among 74 survivors of the Fontan type of operation abnormal cardiac signs were detected in 46 (62%) at postoperative examination. The findings were analysed in relation to the state of the cardiovascular system of these patients. Cyanosis was present in 10 (13.5%) patients. The causes of cyanosis included residual interatrial shunt (six patients), acquired pulmonary arteriovenous fistulas (three patients) and acquired systemic-to-pulmonary vein communication (one patient). Signs of chronic fluid retention were detected in six (8%) patients. In four of them the fluid retention was related to conduit obstruction and in the remaining two it was secondary to severe subaortic stenosis in one and atrioventricular valvar regurgitation in the other. Organic heart murmurs were heard in 29 (39%) patients. The aetiologies of these murmurs were multiple. They included aortic valve regurgitation (eight patients), subaortic stenosis (seven patients), atrioventricular valvar regurgitation (five patients), pulmonary valve regurgitation (five patients), residual Blalock-Taussig shunt (two patients), residual ventricular septal defect (two patients), residual communication in the main pulmonary artery which had been ligated but not divided (one patient), and left ventricular to right atrial shunting (one patient). Cardiac rhythm disturbances of varying aetiology were noted in 23 (31.1%) patients. Sixteen (21%) had supraventricular arrhythmias and seven (9.5%) had conduction abnormalities. The present review suggests that among survivors of the Fontan type of operation abnormal cardiac signs are indicators of residua or sequelae or both of the native cardiovascular anomalies or surgical procedures.

Adolescent↗
PubMed1988

An echocardiographic study of the association of ventricular septal defect and right ventricular muscle bundles with a fixed subaortic abnormality.

Since 1983, 36 patients with the combination of right ventricular muscle bundles and a perimembranous ventricular septal defect have been studied in our institution to address the incidence of on associated subaortic abnormality. Of that total 32 (88%) had echocardiographic evidence of such an abnormality (29 had a typical subarotic ridge protruding from the crest of the interventricular septum and the remaining 3 had an echodense area in the same location). Surgical confirmation of the presence or absence of a subaortic abnormality was available in 26. There was correlation between the surgical and echocardiographic findings in all patients. A resting Doppler gradient of greater than or equal to 10 mm Hg was present in only 10. During the study period, 6 patients had Doppler evidence of progression of their gradient. The incidence of subaortic abnormalities in right ventricular muscle bundles and ventricular septal defects appears to be far greater than previously suspected. The exact significance of this finding in the absence of a pressure gradient is still unclear.

Child, Preschool↗
PubMed1988

Left ventricular systolic and diastolic function after two-stage anatomic correction of transposition of the great arteries.

Anatomic repair of transposition of the great arteries (TGA) has been developed because of concerns about right ventricular function after atrial repair by the Mustard or the Senning technique. This study assessed left ventricular systolic and diastolic function in three patients after two-stage anatomic repair. Two patients had a ventricular septal defect (one with coarctation), and the third patient had right ventricular dysfunction precluding atrial repair. All had pulmonary artery banding. The mean ages at the time of repair and catheterization were 2.75 and 4.9 years, respectively. The control group included 10 patients with insignificant or no cardiac disease. At cardiac catheterization the group with TGA had a higher mean end-diastolic volume index (110.9 +/- 4.74 ml/m2) compared to normal subjects (79.1 +/- 14.55; p less than 0.001), mean end-systolic volume index (37.3 +/- 3.69 vs 22.7 +/- 4.42; p less than 0.001), mass index (101.0 +/- 16.9 vs 68.2 +/- 12.34; p = 0.038), and stroke volume index (73.6 +/- 3.52 vs 56.5 +/- 12.1; p = 0.0027). The ejection fractions, end-diastolic and peak systolic pressures, and stresses were not different. There was no difference in the relationship between the mean rate-corrected velocity of circumferential fiber shortening and end-systolic stress for the group with TGA, but myocardial stiffness was markedly elevated (29.5 +/- 1.84 vs 10.8 +/- 2.20; p less than 0.001). Thus, this study found abnormalities of left ventricular size after two-stage anatomic repair of TGA in this group of patients with TGA.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1988

Successful use of intraaortic balloon pumping in a 2-kilogram infant.

Severe low cardiac output of unknown cause that did not respond to inotropic and ventilatory support developed in a 2-kg infant. Intraaortic balloon pumping was used successfully to acutely improve her cardiac function and peripheral perfusion and to decrease the requirement for inotropic medications. We describe the technique for insertion and the equipment used, as well as our experience with intraaortic balloon pumping in children.

Cardiac Output, Low↗
PubMed1988

Congenital tracheal stenosis: a review of 22 patients from 1965 to 1987.

Twenty-two infants with congenital tracheal stenosis (CTS) were treated in our hospital between 1965 and 1987. Diagnosis was confirmed by endoscopic and radiographic methods. Patients had a spectrum of tracheobronchial lesions from localized stenosis to more complex deformities involving the carina and bronchi. Other anomalies were found in all patients with the occurrence of vascular slings or rings in 11 patients (50%). Six infants treated nonoperatively died from severe CTS and other lethal anomalies. Five of 16 patients (31%) treated surgically survived. Localized CTS in four cases was treated by dilatation, tracheostomy, or tracheal resection with primary anastomosis (two survivors, 2 non-survivors). Funnel-shaped deformities and extensive tracheobroncial stenosis were treated by tracheal reconstruction using a variety of autogenous tissue and prosthetic grafts (three survivors, nine non-survivors). The overall mortality was 77%. A new intratracheal stent was used in two patients. The stent was a flexible steel spring covered with a silicone rubber sheath. In one patient, it was placed within the trachea at the time of repair and removed later with the bronchoscope. A stent was used in a second patient with intermittent airway obstruction following an esophageal tracheoplasty. In this case, the device failed to alleviate the obstruction, and the infant expired from progressive respiratory failure. Issues of importance in the management of infants with CTS are: (1) adequate evaluation of the tracheobronchial tree, (2) awareness that tracheobronchography may precipitate further respiratory decompensation, (3) assessment of vascular and other anomalies requiring surgical correction, and (4) selection of an appropriate therapeutic approach.

Female↗
PubMed1988

Closed heart surgery for congenital heart disease in infancy.

Closed heart surgery in congenital heart disease can be palliative or corrective. Palliative surgery aims at improving the physiologic deficit rather than the anatomic defect of the heart. Palliative procedures aim to increase pulmonary blood flow in cyanotic children with decreased pulmonary blood flow (Blalock-Taussig shunt), decrease pulmonary blood flow when there is unrestricted flow (pulmonary artery banding), or improve venous mixing in cyanotic children that require pulmonary and systemic venous mixing for survival (atrial septectomy). The indications for palliation over corrective surgery have changed over time. Now we reserve palliation for children that require low pulmonary vascular resistance for correction, a conduit that will require replacement as the child grows, or where the risk of the corrective procedure decreases rapidly with age. For palliation with systemic to pulmonary artery shunts, we prefer to perform a Blalock-Taussig subclavian to pulmonary artery shunt using a synthetic (PTFE) tube graft in infants. The operative mortality is higher in infants under 1 month of age but is not affected by weight or diagnosis. Palliative surgery to decrease pulmonary blood flow is restricted primarily to infants with large left-to-right shunts where the risk of correction in infancy is high (multiple VSDs) or not feasible (univentricular heart). The operative risk for pulmonary artery banding is affected mostly by the complexity of the cardiac defect and the clinical state of the infant (severe congestive failure) at the time of surgery. A trial septectomy to improve venous mixing is used mostly in infants with univentricular heart in whom a balloon septostomy was ineffective.(ABSTRACT TRUNCATED AT 250 WORDS)

Alprostadil↗
PubMed1988

Valve surgery in children.

Valve surgery constitutes a small percentage of overall pediatric cardiac practice. Most of the lesions seen are congenital anomalies, often in association with other lesions. Valvotomy and valvuloplasty can usually provide good long term palliation, although reoperation is probably inevitable. The late results of valve replacement in children have been compromised by the rapid calcification of biologic valves. There is some evidence to suggest that this may not occur with homograft valves. The importance of implanting as large a valve as possible is emphasized and follow-up must include an assessment of whether the child is outgrowing the previously implanted prosthesis.

Aortic Valve↗
PubMed1988

Myocardial performance after repair of congenital cardiac defects in infants and children. Response to volume loading.

The hemodynamic response to increasing left atrial pressure by volume loading was evaluated in 70 children during the first 24 hours after repair of congenital cardiac defects. The children were grouped into four diagnostic categories: atrial septal defect or pulmonary valve stenosis (n = 8), ventricular septal defect (n = 36), complete transposition after Mustard's operation (n = 13), and tetralogy of Fallot (n = 13). Within 2 hours of bypass, both cardiac index and left ventricular stroke work index were adequate and increased appropriately with volume loading in all four diagnostic groups. The atrial septal defect group demonstrated a similar response to volume loading 4 and 24 hours after bypass. However, the other three diagnostic groups had a higher filling pressure, lower cardiac index and stroke work index, and a depressed response to increasing preload 4 hours postoperatively, which indicated a deterioration in cardiac performance. The deterioration was maximal between 4 and 12 hours after bypass, and performance tended to recover 24 hours postoperatively. The transposition group had a more profound depression in cardiac performance than the other two groups. Within the ventricular septal defect group, smaller children (body surface area less than 0.36 m2) had a more profound depression in performance than larger children. These results demonstrate a significant alteration in cardiac performance during the first 24 hours after repair of congenital cardiac defects in children. These changes should be considered when postoperative management is being planned.

Cardiac Output↗
PubMed1988

Inadequate myocardial protection with cold cardioplegic arrest during repair of tetralogy of Fallot.

Postoperative low cardiac output is the most common cause of death in patients undergoing elective repair of tetralogy of Fallot. The incidence is much higher than in elective adult bypass operations for coronary artery disease. To explain this difference, we investigated 16 children having elective repair of tetralogy (mean age 6.3 years). Myocardial biopsy specimens obtained during bypass before arrest, at the end of cold arrest by blood cardioplegia, and after 30 minutes of reperfusion were studied for adenosine triphosphate and lactate levels. Myocardium was submitted for microscopic study shortly after the onset of ischemia. The operation was successful in reducing right ventricular-pulmonary artery gradients from 82 +/- 28 to 9 +/- 1 mm Hg, yet seven patients required significant inotropic support (dopamine, greater than 5 micrograms/kg/min) for more than 24 hours and 12 patients needed prolonged use of digoxin and diuretics for right ventricular failure. Tissue levels of adenosine triphosphate and lactate in the tetralogy groups were compared with those in 20 adults with coronary artery disease having similar myocardial protection techniques. Adenosine triphosphate levels in the tetralogy group decreased during cross-clamping (41 +/- 8 minutes) from 24 +/- 3 to 16 +/- 2 mmol/kg dry weight (mean +/- 1 standard error), with a marked further drop after reperfusion to 9 +/- 2 mmol/kg (p less than 0.01). Adenosine triphosphate levels in the group with coronary disease also decreased from 20 +/- 1 to 16 +/- 1 mmol/kg after a longer cross-clamp time (70 +/- 17 minutes) but remained at 15 +/- 2 mmol/kg after reperfusion. Tissue lactate levels in the tetralogy group rose markedly during ischemia and remained elevated after reperfusion. In contrast, lactate levels in the group with coronary disease rose moderately during ischemia and returned to normal early on reperfusion. Microscopic study revealed focal myocyte necrosis in tetralogy of Fallot. Our findings, which demonstrate inadequate myocardial protection of patients with tetralogy during repair, with depression of adenosine triphosphate and increased lactate during ischemia and reperfusion, suggest a defect in oxidative metabolism. The drop in adenosine triphosphate after reperfusion in the patients with tetralogy implicates reperfusion injury as a mechanism of myocardial damage.

Adenosine Triphosphate↗
PubMed1988

Early and late results of a protocol for simple transposition leading to an atrial switch (Mustard) repair.

Inferences: A treatment protocol for patients with simple transposition, consisting of initial balloon atrial septostomy and leading to a delayed atrial switch repair of the Mustard type, in good circumstances, results in survivorship at 1 month, 1 year, 10 years, and 20 years of 95% (95% confidence limits [CL] 90% to 97%), 90% (95% CL 84% to 94%), 83% (95% CL 74% to 90%), and 80% (95% CL 70% to 88%), respectively. Low birth weight adversely affects survivorship. Hypoxia or heart failure accounts for most deaths within the first month and before the atrial switch (Mustard) repair. Most of the few deaths late postoperatively are sudden and they appear to occur particularly in patients who have junctional rhythm. A progressive increase in the prevalence of junctional rhythm has been a risk of the atrial switch repair, and only 76%, 65%, 59%, 56%, and 53% of patients can be expected to be free of this by 1, 5, 10, 15, and 20 years after repair. Important right ventricular dysfunction late after an atrial switch repair, with its adverse affect on the patients' functional capacity, appears to be present in up to 10% of patients after the atrial switch repair, but may not be an immutable risk of this type of repair. About 90% of patients, essentially all of those who do not have right ventricular dysfunction, can be expected to be in New York Heart Association class I or II late postoperatively.

Adult↗