[Interventional treatment of congenital heart defects in infants with a body weight up to 2,500 grams]

Comparative risk of cardiac catheterisations performed on low birth weight neonates

To determine whether cardiac catheterisation procedures for low birth weight neonatesr < or = 2.5 kg carries a greater risk of complications compared with neonates > 2.5 kg, we conducted a single-centre retrospective case–control study. From 01/03 to 01/09, 46 consecutive neonates < 2.5 kg at the time of cardiac catheterisation were identified. For each low birth weight case, three control patients > or = 2.5 kg were randomly selected from our heart centre database during the same time period. Data included demographic characteristics, type of intervention, fluoroscopy time, contrast volume, pre- and post-blood urea nitrogen to creatinine ratio, physician performing procedure, procedural risk category, and all major and minor complications. The overall incidence of complications was higher in neonates < or = 2.5 kg compared with neonates > 2.5 kg (34.8% versus 17.6%, p = 50.023) because of a greater proportion of minor complications (34.8% versus 16.9%, p = 50.021). When specific minor complications were stratified, there was a greater incidence of hypotension requiring intravenous fluids in neonates < or = 2.5 kg (6.5% versus 0%, p50.015). After controlling for physician performing procedure and risk category, neonates < or = 2.5 kg remained at a higher risk for any complication (adjusted odds ratio = 3.2, 95% confidence interval 1.4–7.2, p = 0.005). The percentage of neonates having at least one major complication was not higher in the < or = 2.5-kg group (2.2% versus 2.2%). No procedural deaths occurred in either group.

Bailout stenting for critical coarctation in premature/critical/complex/early recoarcted neonates

BACKGROUND

Surgical repair of critical coarctation can be problematic in premature, critical, complex, or early postoperative neonates.

OBJECTIVES

We aimed to review our experience with stent implantation to defer urgent surgery to an elective time.

METHODS

Fifteen neonates with severe aortic coarctation: five premature-hypotrophic (1,400-2,000 g), six critical and complex cardiac malformation, four early (1 day [0-2 days]; median [range]) after surgical coarctectomy or complex arch reconstruction. Bare coronary stents (diameter 4.0 [3.5-5.0] mm; length 10 [8-16] mm) were used. Stents were removed surgically depending on clinical needs.

RESULTS

Adequate aortic flow was obtained in 15 patients. The femoral artery was preserved in 13/15 patients. Two deaths occurred before stent removal and were nonprocedure related. In patients with simple stented coarctation, the stent was removed after 2.8 [0.2-5.0] months. In complex cardiac malformation, stents were finally removed 3.0 [0.2-78] months after implantation.

SURGICAL TECHNIQUE

simple coarctectomy end-to-end in eight, extensive arch patch reconstruction in four. One patient is awaiting stent removal. The final maximum systolic velocity (cw-Doppler) across the aortic arch was 1.7 [1.2-2.5] m/sec.

CONCLUSIONS

In premature/critical/complex neonates with severe coarctation, bailout stenting followed by early or late surgical coarctectomy appears a promising concept.

Balloon dilation of the pulmonary valve in premature infants with tetralogy of Fallot

Infants with tetralogy of Fallot (ToF) presenting with desaturation may require augmentation of the pulmonary blood flow, usually in the form of a Blalock-Taussig shunt. Shunts may result in a preferential increase in blood flow to one lung. They also may be associated with significant morbidity and possibly mortality of premature infants. Balloon dilation of the pulmonary valve is reported to improve saturation in early infancy. This report describes two premature infants (weighing, respectively, 1.8 and 1.6 kg) with ToF and desaturation for whom balloon dilation of the pulmonary valve showed good results. Neither infant required palliative surgery. At this writing, one infant has already undergone complete repair.

Successful percutaneous balloon valvuloplasty in a preterm infant weighing 1500 g with critical pulmonary valve stenosis

We describe a successful cardiac intervention in an infant, born at 32 weeks of gestation, with a birth weight of 1040 g, who had a critical pulmonary valve stenosis with the right ventricular pressure twice the systemic pressure. Continuous prostaglandin E infusion kept the arterial duct open and at the age of four weeks and a weight of 1500 g a balloon valvuloplasty was performed, which reduced the systolic right ventricular pressure to below the systemic pressure. Two weeks later the procedure was repeated because of increasing right ventricular pressure. At two months of age the mean systolic transpulmonary Doppler gradient was 30 mmHg with an adequate right ventricular volume. The neurological status of the infant was normal and the femoral vein was patent. Timely interventional heart catheterisation is a successful method of treatment in critical pulmonary valve stenosis in infants with a low birth weight. (Neth Heart J 2008;16:264-6.).

Imaging the neonatal heart—Essentials for the radiologist

Modern radiological imaging provides precise diagnosis in congenital heart disease (CHD). The most important and readily available radiological examination is still chest radiography. The diagnostically most important imaging method is echocardiography. Magnetic resonance imaging and computed tomography have gained much ground over the more invasive cardiac catheter angiography, which is still needed in more complex conditions and for interventional procedures, which are performed more frequently. This article is focused on imaging of the neonatal heart. Basically, characteristics of the chest radiograph in CHD are illustrated. To establish an understanding of CHD haemodynamics are reviewed. It is not the role of the radiologist to make a detailed anatomic or physiologic diagnosis on the basis of a plain film, but the radiologist should be aware of changes in a neonatal chest X-ray that CHD can cause and should point out that the child might have CHD thus initiating further work-up.

Biocompatibility screening in cardiovascular implants

BACKGROUND

Interest in information on biocompatibility of implants is increasing. The purpose of this paper is to discuss methods and results of pathological biocompatibility screening of explanted cardiovascular implants.

METHODS

Use of standard histology after embedding in paraffin is limited since metallic implants have to be removed during workup with disruption of the specimen. Alternatively, tissue blocks containing an implant can be embedded in methylmethacrylate or hydroxyethylmethacrylate and processed by sectioning with a diamond cutter and grinding, thus leaving the implant in situ and saving the tissue/implant interface for detection of local inflammatory reactions. Another important aspect of evaluation is the progress of thrombus organisation after initial fibrin clotting on the metal surface or in the inner part of occlusion devices. New methacrylate resins and embedding techniques allow for specific immunohistochemical staining of the specimen thus enabling characterisation of tissues surrounding the implant. Information on endothelialisation of the vascular surface of the implant can be obtained by means of immunohistochemistry or by scanning electron microscopy.

RESULTS

Illustrating the use of these technologies, we demonstrate findings in tissue specimens from animal studies with different types of devices (i.e. stents, occlusion devices). We present corresponding findings in human specimens with implants that were removed during corrective surgery for congenital heart defects. Early endothelialisation of the vascular surface was seen after implantation in all types of devices. Cells within occlusion devices could be characterised histologically and immunohistochemically as fibromuscular cells as seen in intimal hyperplasia after stent implantation. Inflammatory implant-host reactions ranged from mild to moderate (medical grade stainless steel, nitinol) to severe (polytetrafluoroethylene [PTFE]).

CONCLUSIONS

With an optimal work-up of cardiovascular implants, ingrowth and endothelialisation as well as inflammatory reactions in the surrounding tissue can be assessed. This information allows evaluation of individual tissue reactions to the implant and may serve as valuable basis for optimisation of biocompatibility by implant modification.