Gerardus Bennink

Superior vena cava stenting and transvenous pacemaker implantation (stent and pace) after the Mustard operation

SummaryThe Mustard operation for transposition of the great arteries is associated with good long-term survival. Typical complications at follow-up include progressive loss of sinus node function requiring permanent pacemaker implantation, and systemic venous pathway obstruction often precluding a transvenous approach to pacing. We report on 7 patients (median age 14.1; range 5–19) with bradyarrhythmia requiring permanent pacemaker implantation with associated stenosis (n = 6) or occlusion (n = 1) of the superior vena cava, in whom stent implantation relieved the obstruction and facilitated subsequent transvenous permanent pacing. In five of them stenting and pacemaker implantation were performed during a single procedure; two patients underwent elective pacemaker implantation 6 weeks later. In one patient the pacemaker had to be explanted due to pacemaker pocket infection. In the others the follow-up has been uneventful, with excellent chronic pacing thresholds and appropriate sensing. Two patients have had their generator replaced electively.We conclude that stenting of the SVC stenosis allows implantation of transvenous pacemaker leads with good intermediate term results in patients with a Mustard operation for transposition of the great arteries.

Reopening acutely occluded cavopulmonary connections in infants and children.

Little is known about the outcome of acute thrombotic occlusion of segments of the cavopulmonary connections (CPC) in infants and children with univentricular hearts. Early recognition and aggressive therapy may result in successful salvage of some of these patients. Five consecutive patients (age range 4-8 months) presenting with acute occlusion of a CPC segment underwent emergency cardiac catheterization. After angiographic confirmation, the occluded segment was crossed using an endhole catheter and guidewire combination. Serial balloon dilation and stent implantation (ten stents in total) were undertaken to recanalize the occlusion. The stents used were mounted on balloons ranging in diameter from 6 mm to 8 mm, depending on the size of the native vessel. The sites of occlusion were the left pulmonary artery (n=4), and the left-sided superior caval vein (n=3). All occlusions could be successfully recanalized. In three patients, early reocclusion necessitated either surgery or repeat catheterization and angioplasty. There were two early deaths, due to recurrent thrombotic obstruction confirmed either at autopsy or angiography. The remaining patients are alive and well; the majority of survivors have undergone completion of the Fontan operation. A high index of clinical suspicion combined with aggressive therapy can result in successful recanalization in some infants with acutely occluded CPC segments, with acceptable long-term outcome.

Palliative stent implantation for coarctation in neonates and young infants

Background: In selected neonates and infants, primary palliative stent implantation may be indicated for coarctation of the aorta. We describe our experience with this approach in five consecutive patients. Methods: Five neonates and infants (age range 6 to 68 days, gestation 33 to 38 weeks, weight range at procedure of between 1650 to 4000 g) underwent palliative stent implantation as primary therapy for coarctation of the aorta. Indications for primary stent implantation were varied. All procedures were performed by elective surgical cut down of the axillary artery. Standard coronary stents (diameter 4.5 to 5 mm, length 12 to 16 mm) were delivered via a 4F sheath. The axillary artery was repaired after removal of the sheath. Results: All procedures were acutely successful, and without procedural complications. All patients survived to hospital discharge. Four patients have subsequently undergone elective stent removal and surgical repair of the arch, at between 38 and 83 days following stent implantation. Complete stent removal was achieved in three patients. Over a follow-up ranging between 8 weeks and 36 months, none of the patients has had any further complications. Conclusions: This palliative approach is warranted in carefully selected patients. Long-term follow-up is required.

Comparison of arrhythmia incidence after the extracardiac conduit versus the intracardiac lateral tunnel Fontan completion

Background: Early and late arrhythmias are relatively common following completion of the Fontan operation in its original form (direct atriopulmonary connection). They contribute significantly to late morbidity and mortality. The incidence of these arrhythmias, especially late arrhythmias, has been shown to be diminished after the Fontan modification using an intracardiac lateral tunnel to connect the inferior caval vein to the pulmonary arterial system. Little data however are available for arrhythmia incidence following the use of an extracardiac conduit Fontan completion. Aim: To compare a consecutive series of Fontan patients who had undergone Fontan completion either using an intracardiac lateral tunnel or an extracardiac conduit, for early and late arrhythmia incidence. Patients and Methods: The early postoperative course and follow-up data of 51 consecutive survivors (at > 6 months after the Fontan completion) were analysed. The patients fell into 2 categories: those with an intracardiac lateral tunnel Fontan completion (ILT – n=26 (11 with a fenestration); median age at Fontan completion

Perioperative placement of stents for relief of proximal pulmonary arterial stenoses in infants

INTRODUCTION Stenoses in the pulmonary arterial system can have a significant negative impact on the early postoperative course in infants. Early recognition and aggressive management are mandatory. PATIENTS AND METHODS We describe our experience with 8 infants, with ages ranging from 3 to 9 months, weighing from 4.5 to 7.7 kilograms, who presented in the up to 18 days following construction of a shunt from the superior caval vein to the pulmonary arteries with clinical symptoms of obstructed pulmonary flow. We include also 2 infants in whom pulmonary arterial stents were implanted in the operating room. Cardiac catheterization showed significant stenoses or occlusion of the left pulmonary arteries in 9 infants, the right pulmonary arteries in 2, or the superior caval vein in 1, the investigation being prompted by the findings of supraphysiological superior caval venous pressures and systemic hypoxaemia. We implanted a variety of stents mounted on balloons ranging in diameter from 6 to 13 millimetres, with 7 placed across a newly created surgical anastomotic site. RESULTS All stenoses were crossed successfully, and stents implanted satisfactorily in all patients, albeit that 1 infant suffered an acute tear of the left pulmonary artery, requiring immediate reoperation. This patient died 72 hours later due to a diffuse coagulopathy. All other patients demonstrated sustained clinical improvement following the procedure. At follow-up, 7 of the 9 survivors have progressed to completion of the Fontan circulation. Redilation of the stents was required in the interim, prior to completion of the Fontan circulation, in 4 of them. In 2 patients, the previously implanted stents were incised during the Fontan completion, permitting placement of the extracardiac Goretex conduit from the inferior caval vein to the pulmonary arteries. CONCLUSIONS Stents can successfully be implanted perioperatively in the pulmonary arterial system during infancy, and redilated, with improvement in clinical outcome in the majority of those with clinically relevant obstruction.

Cerebral oxygenation monitoring during cardiac bypass surgery in infants with broad band spatially resolved spectroscopy

Neurological impairments following cardio-pulmonary bypass (CPB) during open heart surgery can result from microembolism and ischaemia. Here we present results from monitoring cerebral haemodynamics during CPB with near infrared spatially resolved broadband spectroscopy. In particular, the study has the objective (a) to monitor oxy- and deoxy-hemoglobin concentrations (oxy-Hb, deoxy-Hb) and their changes as well as oxygen saturation during CPB surgery and (b) to develop and test algorithms for the calculation of these parameters from broad band spectroscopy. For this purpose a detection system was developed based on an especially designed lens imaging spectrograph with optimised sensitivity of recorded reflectance spectra for wavelengths between 600 and 1000 nm. The high f/#-number of 1:1.2 of the system results in about a factor of 10 higher light throughput combined with a lower astigmatism and crosstalk between channels when compared with a commercial mirror spectrometers (f/# = 1:4). For both hemispheres two independent channels each with three source-detector distances (&rgr; = 25 . 35 mm) were used resulting in six spectra. The broad band approach allows to investigate the influence of the wavelength range on the calculated haemoglobin concentrations and their changes and oxygen saturation when the attenuation A(&lgr;) and its slope &Dgr;A(&lgr;)/&Dgr;&rgr; are evaluated. Furthermore, the different depth sensitivities of these measurement parameters are estimated from Monte Carlo simulations and exploited for an optimization of the cerebral signals. It is demonstrated that the system does record cerebral oxygenation parameters during CPB in infants. In particular, the correlation of haemoglobin concentrations with blood supply (flow, pressure) by the heart-lung machine and the significant decreases in oxygen saturation during cardiac arrest is discussed.

Extended applications of the Amplatzer vascular plug IV in infants

OBJECTIVE A variety of devices are available for transcatheter closure of unwanted shunts. We describe our experience with the use of the Amplatzer vascular plug IV in a consecutive series of infants. METHODS A total of eight consecutive infants - all born preterm at gestational ages ranging from 24 to 35 weeks - undergoing transcatheter closure of unwanted shunts - persistently patent arterial duct in five patients, an aorta to right atrium fistula in one, multiple aortopulmonary collateral vessels in one, and an azygos vein to left atrium connection in one - are described. Their age, from birth, ranged between 3 and 11 months, and weight between 2.6 and 11.3 kilograms. All devices were delivered using percutaneous arterial or venous vascular access via a large lumen (0.038 inch) 4-French delivery catheter. RESULTS All lesions could be successfully occluded using one or more devices. Device diameters ranged between 4 and 8 millimetres, and exceeded the minimum diameter of the target vessel by 1 to 2 millimetres. Successful occlusion was confirmed either directly at angiography or on follow-up echocardiography. Of the infants who were mechanically ventilated prior to the procedure, three could be successfully weaned following closure of the shunt. There were no procedure-related complications. CONCLUSIONS The new vascular plug IV is cheap and efficacious in closing a variety of shunts in young infants, and warrants further extended clinical application.

Protein losing enteropathy secondary to a pulmonary artery stent

A 2-year-old patient with hypoplastic left heart syndrome presented 6 months following Fontan completion with protein-losing enteropathy (PLE). He had undergone stent implantation in the left pulmonary artery after the Norwood procedure, followed by redilation of the stent prior to Fontan completion. Combined bronchoscopic and catheterization studies during spontaneous breathing confirmed left bronchial stenosis behind the stent, and diastolic systemic ventricular pressure during expiration of 25 mm Hg. We postulate that the stent acts as a valve, against which the patient generates high expiratory pressures, which are reflected in the ventricular diastolic pressure. This may be the cause of PLE.

Stent therapy for acute and chronic obstructions in extracardiac Fontan conduits.

We describe transcatheter therapy for early onset occlusion or stenoses of extracardiac conduits in three children who had undergone Fontan completion. Successful stent implantation was associated with complete resolution of symptoms.

Coarctation of the aorta and vein of Galen malformation - treatment considerations in a severely compromised patient.

A vein of Galen malformation - a rare cause of cardiac insufficiency in neonates - is sometimes associated with coarctation of the aorta, two diseases requiring urgent therapy in the neonatal period. We report on a term neonate in whom we first palliated the coarctation by stent implantation, providing time to treat the vein of Galen malformation by endovascular embolisation. Following this, the coarctation was surgically repaired and the stent was explanted.