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Biomedical subjects

A Pawade

Publications and source records attributed to A Pawade.

At least 19 recordsLinked to original sources
PubMed2004

Myocardial metabolic changes during pediatric cardiac surgery: a randomized study of 3 cardioplegic techniques.

BACKGROUND: Blood cardioplegia and terminal warm blood cardioplegic reperfusion ("hot shot") reduce myocardial injury and improve metabolic recovery in hypoxic but not normoxic experimental models. However, there is little evidence of a benefit of either technique in pediatric clinical practice compared with crystalloid cardioplegia. METHODS: Pediatric patients undergoing cardiac surgery were randomized to receive intermittent antegrade cold crystalloid cardioplegia, cold blood cardioplegia, or cold blood cardioplegia with a hot shot. Right ventricular biopsy specimens were collected before ischemia, at the end of ischemia, and 20 minutes after reperfusion. Cellular metabolites were analyzed. In acyanotic patients postoperative serum troponin I levels were also measured at 1, 4, 12, 24, and 48 hours. RESULTS: Of 103 patients recruited, 32 (22 acyanotic and 10 cyanotic), 36 (24 acyanotic and 12 cyanotic), and 35 (25 acyanotic and 10 cyanotic), respectively, were allocated to the groups receiving cold crystalloid cardioplegia, cold blood cardioplegia, and cold blood cardioplegia with a hot shot. Cyanotic patients were younger, with longer crossclamp times. There were no significant differences in clinical outcomes between cardioplegic methods. The cardioplegic method had no overall effect in terms of adenosine triphosphate, ln(adenosine triphosphate/adenosine diphosphate), or ln(glutamate) in acyanotic patients (P =.11, P =.66, and P =.30, respectively). Also, there was no significant difference between groups in troponin I release. However, in cyanotic patients cold blood cardioplegia with a hot shot significantly reduced the decrease in adenosine triphosphate, ln(adenosine triphosphate/adenosine diphosphate), and glutamate observed at the end of ischemia and after reperfusion compared with the decrease seen in those receiving cold crystalloid cardioplegia (P =.002, P =.003, and P =.008, respectively), with cold blood cardioplegia representing an intermediate. CONCLUSIONS: For cyanotic patients (younger, with longer crossclamp times), cold blood cardioplegia with a hot shot is the best method of myocardial protection. For acyanotic patients (older, with shorter crossclamp times), cardioplegic technique is not critical.

Adenosine Diphosphate↗
PubMed2001

Age-dependent and hypoxia-related differences in myocardial protection during pediatric open heart surgery.

BACKGROUND: Current cardioplegic protection techniques used in pediatric cardiac surgery do not take into consideration age and cyanotic differences. The aim of the present work was to address this question by monitoring clinical outcome, myocardial metabolism, and reperfusion injury in pediatric patients protected by cold-crystalloid cardioplegia. METHODS AND RESULTS: Fifty-eight patients (31 children and 27 infants) with or without hypoxic stress (cyanosis) undergoing open heart surgery with cold-crystalloid cardioplegia were included in the study. Clinical outcome measures assessed included inotropic and ventilatory support, intensive care, and hospital stay. Ischemia-induced changes in metabolism (adenine nucleotides, purines, lactate, and amino acids) were determined in ventricular biopsies collected at the beginning and end of ischemic time (cross-clamp time). Reperfusion injury was assessed by measuring postoperative serial release of troponin I. Evidence was observed of ischemic stress during cardioplegic arrest in children and infants as shown by significant changes in cellular metabolites. Compared with infants, children had significantly less reperfusion injury and better clinical outcome, and these factors were related to duration of ischemic time. Cyanosis did not influence outcome in infants, but cyanotic children showed worse reperfusion injury and clinical outcome than acyanotic children. CONCLUSIONS: Extent of myocardial protection with cold-crystalloid cardioplegia in pediatric open heart surgery is dependent on age and degree of cyanosis.

Age Factors↗
PubMed1998

Superior sternal cleft: construction with a titanium plate.

Sternal cleft is a rare congenital deformity, with a superior cleft being the most common. Although sternal clefting is known to be associated with vascular dysplasia, to our knowledge, we report the first case of superior sternal cleft with cervicofacial hemangiomata and cardiac defects in the absence of true ectopia cordis in a neonate. Early surgery in all cases of sternal clefting is advocated, preferably within the first 4 weeks of life. However, if the child is unfit for operation at this stage, repair should be carried out as soon as the child is stable and fit. The method of choice is primary approximation with the intraoperative precaution of confirming cardiorespiratory stability. We suggest reinforcing the primary approximation with a titanium plate to achieve rigid internal fixation and to reduce the tension at the approximation site. Because titanium osseointegrates well, this procedure results in a solid bony sternum.

Bone Plates↗
PubMed1995

Heart transplantation for chyloptysis after Fontan operation.

Chyloptysis is a rare clinical problem, fewer than 10 patients having been reported in the literature. We report a patient with intractable chyloptysis associated with a Fontan procedure, who was palliated by heart transplantation.

Bronchial Fistula↗
PubMed1995

Cardiac anatomy in patients undergoing the Fontan procedure.

BACKGROUND: Controversies in nomenclature, especially of hearts with "single ventricle," have clouded discussion and understanding of the anatomy. Many patients with such malformations are submitted to the Fontan procedure as definitive surgical palliation. The spectrum of anatomy among these patients is wide and deserves analysis in an effort to provide a simple framework for description and to eliminate confusion. METHODS: We reviewed 138 successive patients undergoing the Fontan operation at one institution to demonstrate the variability in pathology. RESULTS: Only 89 patients (65%) had a univentricular type of atrioventricular connection. All but 5 patients had two ventricular chambers. Among the 49 patients with biventricular atrioventricular connections, 43 had a hypoplastic ventricle that precluded a biventricular repair. CONCLUSIONS: Full understanding of the malformations that may preclude a "biventricular" repair and hence necessitate a Fontan procedure requires knowledge of the different forms of univentricular atrioventricular connection that, although usually associated with two ventricular chambers, are seldom amenable to a "two-pump repair." Understanding of those types of "biventricular heart" that preclude a two-pump repair (eg, severe hypoplasia of the left ventricle or the right ventricle) or are associated with high risks (eg, straddling atrioventricular valve) is also important.

Fontan Procedure↗
PubMed1995

Pulmonary artery size after bidirectional cavopulmonary connection.

Pulmonary arterial size was measured during cineangiography in 23 patients, 1.9 months before, and 14 months after bidirectional cavopulmonary connection (BCPC). Measurements were standardized for body surface area using the method of Nakata and co-workers (pulmonary artery index). There was a significant reduction in pulmonary artery index after BCPC. These data suggest that pulmonary arterial growth is impaired after the creation of a BCPC. This may be related to an absolute reduction in pulmonary arterial flow, and/or the loss of systolic expansion of the pulmonary artery.

Cardiac Catheterization↗
PubMed1995

Surgical intervention for infective endocarditis in infancy and childhood.

BACKGROUND: Infective endocarditis is an uncommon but serious disease in children. Optimal treatment strategy, especially surgical indications, continues to evolve. METHODS: Retrospective review of 98 patients treated for infective endocarditis during the past 13 years at the Royal Children's Hospital, including medically and surgically treated patients. RESULTS: Thirty of 98 patients had surgical intervention with 6.7% hospital mortality, and 76% survival probability at 45 months. The remaining patients were treated medically, with 10% hospital mortality and 52% 5-year survival probability. The incidence of structural heart disease, congestive heart failure, and spectrum of organisms was similar in the two groups. CONCLUSIONS: Despite advances in antibiotic therapy, early surgical intervention is required in a significant subset. Concurrent intracardiac repair may be appropriate.

Adolescent↗
PubMed1994

Arterial switch: translocation of the intramural coronary artery.

Translocation of an intramural coronary artery is one of the most challenging problems in anatomic correction of transposition of the great arteries. Of 259 patients undergoing arterial switch procedure for transposition of the great arteries in our hospital, 12 (4.6%) were found to have intramural coronary arteries. The diagnosis was made intraoperatively in all patients. There were five different types of intramural coronary anatomy noted, with ostial stenosis present in half. The operative technique consisted of detachment of the posterior commissure of the aortic valve and unroofing of the intramural segment of the coronary artery by excision of a triangular portion of internal aortic wall. The coronary arteries were excised as a single disc, which was divided into two cuffs. The arterial switch was then performed in the usual fashion. The posterior commissure of the aortic valve was resuspended to the pericardial patch used to reconstruct the neopulmonary artery sinus. There were no operative or late deaths over a follow-up of 328 patient-months. Postoperatively, no patient showed ischemic changes on electrocardiogram or abnormal wall motion on echocardiogram. We believe that intramural coronary arteries can be managed satisfactorily with this technique, and that arterial switch will be possible in all cases.

Coronary Vessel Anomalies↗
PubMed1994

Management strategy in neonates presenting with pulmonary atresia with intact ventricular septum.

The management of neonates with pulmonary atresia and intact ventricular septum presents a challenging problem mainly because of the profound heterogeneity of the morphology of the right ventricle. This article outlines a different approach to the management based on the presence or absence of a well-formed infundibulum (outflow) of the right ventricle. In most of the children with a well-formed infundibulum, successful biventricular repair can be achieved, after promoting the growth of the right ventricle by promoting ategrade flow through it. In patients with poorly formed or an absent infundibulum, on the other hand, a Fontan procedure is an excellent solution.

Clinical Protocols↗
PubMed1994

Surgical management of Marfan syndrome in children.

Between August 1983 and January 1991, seven patients with Marfan syndrome underwent surgery for severe cardiovascular complications. The mean age at presentation was 5.7 months (range 4 to 9 months) in the infant group (n = 3), and 13.3 years (range 10 to 16 years) in a group of older children (n = 4). The primary indications for surgery in the infant group (performed at a mean of 3 years after diagnosis) were ascending aortic aneurysm with valvar regurgitation in one patient, and severe mitral valve prolapse with regurgitation in two. In the older group, surgical indications (performed at a mean of 2.8 years after diagnosis) were ascending aortic aneurysm with valvar regurgitation in three patients and acute aortic dissection in one. For aortic surgery, a composite valved conduit was used in four patients, and an aortic homograft in one. For mitral valve surgery, mechanical prostheses were used. All patients survived the primary operation. Over a mean follow-up of 17.5 patient-years (range 1 to 9 years), two patients in the infant Marfan group went on to further successful surgery (prosthetic mitral valve replacement and aortic root repair with aortic homograft) at a mean interval of 4.3 years after the initial surgery. Our results suggest that the major cardiovascular risk factors of Marfan syndrome in the young, even in those diagnosed during infancy, have been favorably changed by surgery with an encouraging medium-term outlook. The correct timing of surgery is aided by echocardiography.

Adolescent↗
PubMed1993

Pulmonary atresia with intact ventricular septum: surgical management based on right ventricular infundibulum.

The optimal management of infants with pulmonary atresia with intact ventricular septum (PA.IVS) remains a controversy. Attempts have been made to base the surgical approach on various geometrical or morphological characteristics of the right ventricle (RV). However, the overall results remain poor when compared to other complex congenital heart defects. Forty-eight neonates with PA.IVS were admitted to our unit between 1980 and 1992. The management plan has evolved to be based entirely on the echocardiographic assessment of the state of development of the infundibulum of the RV. In neonates with a well-formed infundibulum (n = 31), the initial palliation consisted mainly of pulmonary valvotomy (without cardiopulmonary bypass) and PTFE shunt from the left subclavian artery to the main pulmonary artery. There was one death from initial palliation in this subgroup. If necessary, the RV cavity was later enlarged by excision of the hypertrophic muscle of both the trabecular and infundibular portions, before finally attempting biventricular repair. The actuarial probability of achieving a biventricular repair at 40 months of age was 60% (95% CL = 39.5% to 71.3%). Thirteen patients have undergone biventricular repairs with one late death over a total follow-up of 1,720 patient months. In one patient, the RV failed to grow satisfactorily, necessitating a Fontan procedure. Seventeen patients without a well-formed infundibulum were approached with a Fontan procedure in mind. The initial palliation in these patients consisted of a modified Blalock-Taussig shunt only. Ten have undergone a Fontan procedure so far and five are awaiting such repairs. In this group there were four operative deaths: two after initial palliation, and two after Fontan procedures. In patients with a well-developed infundibulum, the actuarial survival probability was 93% (95% CL = 74% to 98%) at 8 months with no further late deaths over 120 months follow-up, whereas in patients without a well-formed infundibulum it was 75% at 40 months (95% CL = 46% to 89%). The overall survival probability at 104 months was 77% (95% CL = 51% to 90%).

Actuarial Analysis↗
PubMed1993

Cardiopulmonary bypass in neonates weighing less than 2.5 kg: analysis of the risk factors for early and late mortality.

A low weight has been implicated as one of the major reasons for deferring cardiac surgical procedures on cardiopulmonary bypass (CPB), resorting instead to palliative procedures. The purpose of this study is to analyze the risk factors associated with an increased mortality for surgery using CPB in small infants, and to compare this group with infants weighing over 2.5 kg. Between 1979 and 1990, 60 infants weighing less than 2.5 kg underwent surgery on CPB at our institute. The mean age was 17.9 days (range 1 to 68 days, SD = 16.4) and the mean weight was 2.1 kg (range 1.2 to 2.5, SD = 0.35). Eight had univentricular and 52 had biventricular repairs. The hospital mortality was 16.5% (70% CL 11.5% to 22.7%). The actuarial survival over 100 months was 67.5% (including hospital mortality). Over the same period, 946 patients under the age of 6 months but weighing more than 2.5 kg underwent surgery on CPB with a lower hospital mortality of 7.1% (70% CL 6.3% to 8.0%, p < 0.006). The risk factors associated with an increased risk of early death in the group weighing less than 2.5 kg were analyzed using logistic regression. They were: (1) presence of preoperative metabolic acidosis; (2) univentricular versus biventricular repair; and (3) duration of CPB. Within the less than 2.5 kg group, low weight per se did not affect the outcome adversely. The main cause of late death was the presence of associated medical conditions, notably bronchopulmonary dysplasia and tracheo bronchomalacia.

Cardiopulmonary Bypass↗
PubMed1993

Recent results with the modified Fontan operation.

From Jan 1989 to December 1991, 61 patients had modified Fontan procedures for a variety of lesions, including tricuspid atresia (18), mitral atresia (3), double inlet ventricle (14), isomeric hearts (4) and others (22). The hospital mortality was 1.6% (70% CL.0.2-5.3%). There were 2 late deaths. The median age at operation was 3.7 years (mean 5.6, range 1.5 to 20.3 years). There were two late failures at 2 months and 30 months after the operation, requiring take down of the Fontan in one and heart transplantation in the other. The 89% of the patients followed up are in NYHA class I or II at a mean follow up of 21.5 months (range 3-35 months). This suggests that the modified Fontan operation performed with the current patient selection criteria can be performed with a low mortality and that the early results are encouraging in the majority of the patients.

Adolescent↗
PubMed1992

Pulmonary artery sling.

Eighteen patients who underwent surgical treatment of pulmonary artery sling at this institution since 1969 were reviewed. Four of them had associated tracheal stenoses produced by complete cartilaginous rings (stovepipe trachea). All patients underwent operation. The median age at operation was 180 days (range, 27 days to 54 months). In the 14 patients with isolated pulmonary sling, the operation consisted of division of left pulmonary artery and reimplantation into the main pulmonary artery anterior to the trachea. In the 4 patients with stovepipe trachea, the stenotic tracheal segment was resected on cardiopulmonary bypass and the left pulmonary artery was brought anterior to the trachea before the latter was reanastomosed to the main pulmonary artery. There were no early deaths. One patient died late. The pulmonary artery anastomosis was patent in all 14 patients investigated postoperatively. Three patients have residual tracheobronchial problems. One patient is mentally retarded and is institutionalized. All other patients are symptom-free and growing normally and have normal chest radiographs.

Child, Preschool↗
PubMed1992

Complex coronary arterial anatomy in transposition of the great arteries. Arterial switch procedure without coronary relocation.

Translocation of the coronary arteries remains a technical problem in anatomic correction of transposition of the great arteries. Myocardial ischemia related to difficulties with coronary relocation is a significant factor in perioperative morbidity and mortality, particularly in those patients with complex coronary anatomy. Two neonates with transposition of the great arteries and intact ventricular septum are described in whom the coronary arteries arose from multiple ostia, all lying within sinus 1, with one of the ostia in each instance being severely eccentric. An anatomic switch of the great vessels was done without coronary relocation. This was achieved by means of an aortopulmonary fenestration with a bovine pericardial tunnel to allow coronary artery perfusion with blood from the neoaorta. An additional pericardial patch was placed to the contralateral wall of the proximal neopulmonary artery. Both infants had an uneventful postoperative recovery with no evidence of myocardial ischemia, although both have a mild gradient across the proximal pulmonary artery. This operative technique may be appropriate in those patients in whom there is concern over the feasibility of translocating the coronary arteries without producing myocardial ischemia.

Anastomosis, Surgical↗
PubMed1990

Circulatory support in infants with post-cardiopulmonary bypass left ventricular dysfunction using a left ventricular assist device.

Extracorporeal membrane oxygenation has been advocated as the most appropriate mode of circulatory support in the paediatric age group for post-cardiopulmonary bypass ventricular dysfunction. The results in infants who have predominantly left ventricular failure, or who require such support in order to be weaned off bypass, have been disappointing. Three infants with severe left ventricular dysfunction following cardiopulmonary bypass for correction of congenital heart defects have been managed with a left ventricular assist device. Two required this form of circulatory support in order to be weaned from full bypass while in the third infant it was instituted for progressive left ventricular dysfunction postoperatively. All three were less than 10 kg in weight. Left atrial appendage to aortic bypass was effected using a closed loop circuit with a constrained vortex pump (Biomedicus). Duration of support ranged between 40 and 146 h. One infant made a complete recovery and was able to be discharged home 20 days postoperatively. Another made a circulatory recovery such that both mechanical and inotropic support could be discontinued but had sustained massive neurological damage. The third died of progressive left ventricular dysfunction. This experience with a left ventricular assist device demonstrates that it is technically feasible in small infants, and can be performed to good effect in infants with predominant left ventricular dysfunction following cardiac surgery. It may well be more appropriate than extracorporeal membrane oxygenation in this group of patients.

Cardiac Output, Low↗