Impact of delayed systemic heparinization on postoperative bleeding and thromboembolism during post-cardiotomy extracorporeal membrane oxygenation in neonates

INTRODUCTION

Veno-arterial extracorporeal membrane oxygenation is well-established for pediatric patients with post-cardiotomy heart failure. However, extracorporeal membrane oxygenation support is associated with major complications, that is, hemorrhage and thromboembolism. We seek to report our experience with delayed systemic heparinization during neonatal cardiac extracorporeal membrane oxygenation and its impact on bleeding and thromboembolism.

METHODS

We retrospectively identified 15 consecutive neonates who were placed on extracorporeal membrane oxygenation after congenital heart surgery during a period of 3 years (2015-2017). Our anticoagulation protocol consisted of full heparin reversal by protamine after switching from cardiopulmonary bypass to extracorporeal membrane oxygenation (target activated clotting time: 120 ± 20 seconds). Administration of systemic heparinization was delayed until postoperative drainage volume declined to <1 mL/kg/h. Primary study endpoints were thromboembolism, bleeding, and requirement of blood products on extracorporeal membrane oxygenation.

RESULTS

Our cohort (mean age: 13 ± 2.6 days; mean weight: 3.1 ± 0.3 kg; 66.7% male) required post-cardiotomy extracorporeal membrane oxygenation with a mean support time of 4.5 ± 2.2 days. Systemic heparinization was delayed averagely for 18.1 ± 9.3 hours. No thromboembolic events were observed on extracorporeal membrane oxygenation or after weaning. Relevant surgical site bleeding occurred in two patients (13.3%) requiring re-thoracotomy on the first postoperative day. Analysis of transfusion volumes revealed 24.5 ± 21.9 mL/kg/d mean packed red blood cells, 9.6 ± 7.1 mL/kg/d mean fresh frozen plasma, and 7.5 ± 5.7 mL/kg/d mean platelets. In-hospital survival was 86.6% (n = 13).

CONCLUSION

In this retrospective analysis, the results of delayed systemic heparinization in neonatal post-cardiotomy extracorporeal membrane oxygenation could lead one to conclude that this routine is safe and favorable with low risk for thromboembolic events, reduced postoperative hemorrhage, and reduced blood product utilization.

Autologous Tissue Technique to Repair Unilateral Isolated Absence of a Pulmonary Artery

Isolated unilateral absence of a pulmonary artery (UAPA) is a rare congenital anomaly in which one branch pulmonary artery has no connection to the main pulmonary trunk (most often there is ductal origin). Without treatment, it may lead to ipsilateral pulmonary hypoplasia and contralateral pulmonary artery hypertension. To avoid these complications, early surgical repair of UAPA is necessary. Surgical strategies include direct anastomosis between the "isolated" branch pulmonary artery (PA) and the main pulmonary trunk or creation of an interposition graft using prosthetic material or flap techniques. We describe a surgical technique using a totally autologous interposition tube graft.

Towards a Tissue-Engineered Contractile Fontan-Conduit: The Fate of Cardiac Myocytes in the Subpulmonary Circulation

The long-term outcome of patients with single ventricles improved over time, but remains poor compared to other congenital heart lesions with biventricular circulation. Main cause for this unfavourable outcome is the unphysiological hemodynamic of the Fontan circulation, such as subnormal systemic cardiac output and increased systemic-venous pressure. To overcome this limitation, we are developing the concept of a contractile extracardiac Fontan-tunnel. In this study, we evaluated the survival and structural development of a tissue-engineered conduit under in vivo conditions. Engineered heart tissue was generated from ventricular heart cells of neonatal Wistar rats, fibrinogen and thrombin. Engineered heart tissues started beating around day 8 in vitro and remained contractile in vivo throughout the experiment. After culture for 14 days constructs were implanted around the right superior vena cava of Wistar rats (n = 12). Animals were euthanized after 7, 14, 28 and 56 days postoperatively. Hematoxylin and eosin staining showed cardiomyocytes arranged in thick bundles within the engineered heart tissue-conduit. Immunostaining of sarcomeric actin, alpha-actin and connexin 43 revealed a well -developed cardiac myocyte structure. Magnetic resonance imaging (d14, n = 3) revealed no constriction or stenosis of the superior vena cava by the constructs. Engineered heart tissues survive and contract for extended periods after implantation around the superior vena cava of rats. Generation of larger constructs is warranted to evaluate functional benefits of a contractile Fontan-conduit.

A multicentre evaluation of the autograft procedure for young patients undergoing aortic valve replacement: update on the German Ross Registry†

OBJECTIVES

Conventional aortic valve replacement (AVR) in young, active patients represents a suboptimal solution in terms of long-term survival, durability and quality of life. The aim of the present work is to present an update on the multicentre experience with the pulmonary autograft procedure in young, adult patients.

METHODS

Between 1990-2013, 1779 adult patients (1339 males; 44.7 ± 11.6 years) underwent the pulmonary autograft procedure in 8 centres. All patients underwent prospective clinical and echocardiographic examinations annually. The mean follow-up was 8.3 ± 5.1 years (range 0-24.3 years) with a total cumulative follow-up of 14 288 years and 662 patients having a follow-up of at least 10 years.

RESULTS

The early (30-day) mortality rate was 1.1% (n = 19). Late (>30 day) survival of the adult population was comparable with the age- and gender-matched general population (observed deaths: 101, expected deaths: 91; P = 0.29). Freedom from autograft reoperation at 5, 10 and 15 years was 96.8, 94.7 and 86.7%, respectively, whereas freedom from homograft reoperation was 97.6, 95.5 and 92.3%, respectively. The overall freedom from reoperation was 94.9, 91.1 and 82.7%, respectively. Longitudinal modelling of functional valve performance revealed a low (<5%) probability of a patient being in higher autograft regurgitation grades throughout the first decade. Similarly, excellent homograft function was observed throughout the first 15 years.

CONCLUSION

The autograft principle results in postoperative long-term survival comparable with that of the age- and gender-matched general population and reoperation rates within the 1%/patient-year boundaries and should be considered in young, active patients who want to avoid the shortcomings of conventional prostheses.

Outcomes of aortic coarctation surgical treatment in adults

OBJECTIVE

The aim of this study is to describe our experience in aortic coarctation surgery in adult patients by assessing the immediate and mid-term outcomes.

METHODS

From January 1987 to March 2000, 50 consecutive adult patients underwent surgery for correction of aortic coarctation, through left lateral thoracotomy. Of these, forty two (84%) patients presented high blood pressure, with mean systolic arterial pressure of 170.56 mmHg (125-220 mmHg). The mean of pressure gradient in the coarctation area was 51.4 mmHg (18-123 mmHg). Other associated surgical cardiovascular diseases were not treated in the same operative act, except in two cases of patent ductus arteriosus (PDA). Three different techniques were used: aortic coarctation resection with end-to-end anastomosis was performed in 20 (40%) patients, coarctation enlargement with bovine pericardial patch was performed in 22 (44%) patients and synthetic tube interposition was performed in eight (16%) patients.

RESULTS

Operative morbidity was low; there was one case of bleeding who required reoperation. The most common immediate postoperative event was high blood pressure (98%), but it was easily controlled by intravenous drugs. There was no hospital death. Mean residual pressure gradient was 18.7 (8-33 mmHg). Patients were discharged in 9.5 days (5-30). Postoperative follow-up mean was 46.8 months (1-145 months) in 45 (91.8%) patients. Forty one (91.1%) of these followed-up patients had normal blood pressure, whereas 75.6% of them without drugs intake. 93.3% of these followed-up patients were asymptomatic. Four of them required further surgical operation, one needed a pacemaker implant, other two patients needed a cardiac valve replacement and one had endocarditis. There was one related death due to sepsis secondary to endocarditis.

CONCLUSION

Surgical treatment of aortic coarctation, even in adult patients, is an efficient therapeutic choice, regardless of the applied surgical technique, with low morbidity and mortality. It reduces efficiently the arterial pressure levels in both immediate and mid-term follow-up.

Pediatric heart transplantation in refractory cardiogenic shock: a critical analysis of feasibility, applicability and results

BACKGROUND

In children with dilated cardiomyopathy who are on the waiting list for heart transplantation, we evaluate the seriousness of their hemodynamic conditions. Some develop cardiogenic shock, and the mortality rate is high. Even with inotropic and respiratory support, heart transplantation is considered an extremely grave circumstance.

OBJECTIVE

The objective of this study is to report on our experience with children in this condition, in an attempt to analyze the viability, applicability and results of heart transplantation in these children.

METHODS

From March 2001 to February 2004, 22 children with dilated cardiomyopathy who were on the waiting list for heart transplantation developed cardiogenic shock, requiring transfer to pediatric intensive care unit (ICU), intubation and inotropic support. Their ages ranged from 11 months to 11 years (mean age: 4.3 years), 55% were males, 14 could be listed as clinical priority, and the remaining 8 were removed from the waiting list due to their unfavorable clinical conditions.

RESULTS

Eight heart transplantations were performed, and 6 children died while on the waiting list (42.9%). Two children died (25%) after transplantation and the remaining 6 were discharged from hospital in good clinical condition. The two main complications were organ rejection in 4 cases and infection in 5 cases. Two patients developed neurological complications, and one of them fully recovered.

CONCLUSION

Children with cardiomyopathy and cardiogenic shock require immediate heart transplantation; only 57.1% could be transplanted, with an early 25% mortality rate. Those who survived transplantation showed good clinical progress, similar to that of children transplanted on an elective basis.

Ascending Aortic Aneurysm After Pediatric Heart Transplantation: Case Report of an Unusual Complication

A 28-month-old boy, weighing 11 kg, with severe dilated cardiomyopathy, was transplanted on December 1995. Hypertension and supraventricular tachycardia were detected in the immediate post-operative period, with favorable outcome. After 5 months of clinically asymptomatic follow-up, a dilation in the ascending aorta was observed on routine echocardiogram. Nuclear magnetic resonance imaging (NMRI) confirmed an ascending aortic aneurysm, with a diameter of 38 mm. An operation was performed, a bovine pericardium patch was sutured with reconstruction of the aortic wall, excluding the aneurysm. Good recovery was obtained and the child was discharged on Day 7 postoperatively. A post-operative echocardiogram showed absence of the aortic aneurysm and good surgical results. Another NMRI was done 5 months later, showing an intact ascending aorta. After 64 months, the patients clinical condition was confirmed as normal by echocardiogram. Surgical treatment was successful and the positive results have been maintained.

Long-term results of correction of tetralogy of Fallot in adulthood

OBJECTIVES

The natural history of tetralogy of Fallot (TOF) allows that a minority of patients reach adulthood without any treatment, representing mild forms of the disease. The aim of this study is the long-term evaluation of patients with TOF surgically treated in adulthood, in order to define its real benefit.

METHODS

Between November 1982 and January 2001, 39 patients older than 18 years of age with tetralogy of Fallot underwent total correction. Mean age was 26.6 years (range 18-67) and 21 patients (53.8%) were females. A previous modified Blalock-Taussig shunt was performed in four patients (10.3%). Fifteen patients (38.5%) were in NYHA functional class III or IV. Mean hematocrit was 53.6+/-10% and the mean gradient across the right-ventricular outflow tract was 93.9+/-24.8 mmHg. The operation was performed via transatrial/transpulmonary approach in 16 patients (41%) and six patients (15.4%) required transannular patch. Pulmonary valvotomy was necessary in 13 patients (33.3%) and pulmonary valve replacement with bioprosthesis in 3 patients (7.7%).

RESULTS

Hospital and late mortality were 5.1 and 7.7%, respectively. The mean follow-up was 45.1 months (range 1-194 months). Actuarial survival was 91.2+/-4.9%, 85.5+/-7.2% and 68.4+/-16.3% at 3, 7 and 15 years, respectively. In the latest follow-up, 27 (79.4%) of the survivals are presently in NYHA functional class I (P<0.001). Echocardiography has shown moderate/severe pulmonary insufficiency in 9 patients (26.5%), moderate pulmonary stenosis in 3 patients (8.8%) and residual ventricular septal defect in 4 patients (11.8%). Arrhythmias were identified in 38.9% of patients with symptoms suspicious of rhythm disturbances. There was impairment of right-ventricular function in 13 patients (38.2%). Three patients were reoperated on to close residual ventricular septal defects in two patients and for pulmonary valve replacement in one patient.

CONCLUSIONS

The overall survival of surgically treated adult patients with TOF is acceptable. The great benefit of the complete repair at this age is the functional improvement. On the other hand, late complications closely related to chronic hypoxia, such as arrhythmia and ventricular dysfunction might direct for a more careful follow-up after the surgical correction.

Choreoathetosis after cardiac surgery with hypothermia and extracorporeal circulation

Eleven children, 4-48 months old, with congenital cyanotic heart defects developed choreoathetoid movements 2-12 days after cardiac surgery with hypothermia and extracorporeal circulation (ECC). The abnormal movements mainly involved the limbs, facial musculature, and tongue, leading to a severe dysphagia. The symptoms had an acute onset, after a period of apparent neurologic normality, and had a variable outcome. Of the nine children that survive, three had abnormal movements when last seen (41 days to 12 months of follow-up). The other six children had a complete regression of the choreoathetoid movements 1-4 weeks after onset. No specific finding was observed in the CT scans, cerebrospinal fluid examination, or EEG that could be related to the abnormal movements. Symptomatic therapy with haloperidol with or without benzodiazepines led to symptomatic improvement in six children, although there was no evidence that this treatment modified the evolution of the disease. The authors conclude that the choreoathetoid syndrome after cardiac surgery with deep hypothermia and ECC is an ill-defined entity requiring additional study to better understand its pathogenesis so that preventive measures can be taken to avoid a condition that can lead to permanent and incapacitating neurologic sequelae.

[Neonate and infant heart transplantation]

PURPOSE

Heart transplantation has offered children with complex congenital heart diseases and severe cardiomyopathies a chance for survival. The present article was written to show the three year experience of this procedure at the Instituto do Coração-HCFMUSP.

METHODS

The methodology used was based on heart transplant indication criteria, inclusion criteria for donors, postoperative management, immunosuppression and prophylaxis as well as treatment of potential complications.

RESULTS

From November 1992 to November 1995, 11 children, aged 12 days old to six years (mean 2.5 years) underwent transplantation. Sixty percent of recipients were male; weight ranged from 3.5 to 17.8 kg (mean 10.3 kg). The mean age of donors was 4.4 years (a range of three weeks to ten years), 80% male, weight ranging from 3.8 to 20 kg (median 14.3 kg). The survival rate was 91% and the remaining 10 children are doing well. The most important complications were systemic hypertension, acute rejection and infection. The number of rejections and infections per patient were 3.5 and 4.7 episodes, respectively. The follow-up was between one month to three years (average 16 months).

CONCLUSION

In this experience, heart transplantation has given an additional opportunity for children with complex congenital heart diseases and cardiomyopathies, with a survival rate of 91% in three years.

[Anomalous origin of the left coronary artery. Concomitant correction with valvar replacement for mitral insufficiency]

A four year-old boy with an anomalous origin of the left coronary artery (LCA) directly from the right pulmonary artery was reported. He had been underwent to mitral valve replacement by a St Judes no. 29, due to severe mitral insufficiency, secondary to an extensive myocardial infarction including the anterior and posterior papilary muscles, beside the implantation of the LCA in the aorta. Instead of this favorable outcome, it's emphasized the need for earlier recognition to avoid risk sequelae.

Left ventricular apical approach for the surgical treatment of congenital mitral stenosis

From June 1987 to October 1991, 12 patients with congenital mitral valve stenosis underwent surgical correction. Their ages ranged from 2 to 74 months. Nine patients were less than 22 months of age. Five patients were in New York Heart Association functional class IV, and seven patients were in class III. In nine, parachute-type mitral stenosis was clearly definite. In three, a complex congenital valvular and subvalvular stenosis was found. Associated anomalies were present in every patient; five had undergone previous operations. Correction of the mitral stenosis was done through an apical left ventriculotomy. The removal of the mitral obstruction starts from below; the papillary muscle was split and the chordae were divided or fenestrated. The commissurotomies were performed from the ventricular aspect of the mitral valve. Associated anomalies were corrected simultaneously. The operative mortality rate was zero. There was one late death, which was unrelated to cardiovascular status. The echocardiographic serial postoperative studies (up to 52 months) showed no significant residual mitral stenosis and normal global and regional function of the left ventricle in all but one patient.

A technique for correction of truncus arteriosus types I and II without extracardiac conduits

A new corrective operation for truncus arteriosus without the use of an extracardiac conduit was performed in seven patients with truncus type I (six patients) or type II (one patient) aged from 2 to 9 months. The common truncus arteriosus was septated with a patch into aortic and pulmonary segments and the ventricular septal defect was closed through a ventriculotomy. A direct anastomosis between the pulmonary arteries and the right ventricle was performed, the anterior wall being constructed with a patch with a monocusp valve. There was one death in the immediate postoperative period. In the surviving six patients the postoperative right ventricular/left ventricular peak systolic pressure ratio was less than 0.51 in five and 0.60 in one with a residual ventricular septal defect. All are in functional class I between 1 and 14 months after the operation. On the basis of these results, we propose this technique for patients with truncus type I or II in the first year of life.

Activation of 2',5'-oligoadenylate synthetase and B-2 microglobulin in cancer patients treated with partially pure gamma interferon: dependence of biological effect on administration route

Partially pure immune (gamma) interferon (IFN-gamma) was administered to patients intramuscularly (IM), by rapid IV bolus, and by 6-h continuous infusion as part of a phase I clinical trial. The activity of 2',5'-oligoadenylate synthetase (2,5 A) in peripheral blood cells and the concentration of beta-2 microglobulin (B-2M) in serum were monitored as indicators of interferon biological activity in vivo. Five patients received IFN-gamma by the IM route in doses ranging from 6.5 X 10(5) to 9.6 X 10(6) antiviral units daily. There was little induction either of serum B-2M or of 2,5A in peripheral blood cells. Eight patients received IFN-gamma by rapid (5 min) IV bolus infusion in doses ranging from 6.5 X 10(5) to 54 X 10(6) antiviral units daily. As with IM administration, there was little significant induction of 2,5A synthetase, but the concentration of B-2M was increased above pretherapy values in most patients. Eleven patients received IFN-gamma by 6-h infusion daily for 10 days at a dosage of 27 X 10(6) units/day. In contrast to IM and IV bolus administration, 6-h infusion of IFN-gamma resulted in significant induction of both B-2M serum concentration and of 2,5A activity in all patients. The induction of 2,5A was highest on days 2 and 4 of therapy and decreased to pretherapy values by day 7. During the second 10-day course of the infusion study 2,5A activity was not induced until day 7 of therapy, and it decreased rapidly thereafter. These studies show clearly that consistent biological activity such as B-2M activation and specific intracellular biochemical events such as 2,5A induction may be optimally obtained by the administration of IFN-gamma by continuous IV infusion.