Severe aortic root dilatation in infantile Marfan syndrome.

Cardiovascular manifestations of Marfan syndrome are associated with increased mortality, especially in the pediatric population. Early recognition is critical to long-term management. We present two cases of genetically defined "classical" Marfan syndrome presenting with severe infantile aortic root dilatation among siblings and discuss options for therapy.

Optimum position of transthoracic intracardiac line following cardiac surgery.

OBJECTIVES: The transthoracic intracardiac line placed in the right atrium provides a convenient access to the central venous system following cardiac surgery. However, it is associated with risks such as migration and bleeding. We conducted a retrospective study to determine whether position of transthoracic line with respect to site of exit from the chest makes a difference in the rate of complications. METHODS: All infants receiving a transthoracic intracardiac line in the right atrium following cardiac surgery between June 2012 and December 2015 were part of the study. A 3.5-Fr double-lumen umbilical venous catheter was placed directly into the right atrium. The lines exited the thorax either above in the suprasternal notch (upper transthoracic line) or below the diaphragm across the abdominal wall (lower transthoracic line). Patients were analysed for complications such as catheter migration, bleeding upon removal, atrial thrombus, line occlusion, premature removal and failed removal. RESULTS: A total of 131 patients received a transthoracic intracardiac line during the study period. Of the total patients, 88 patients received the upper transthoracic line and 43 patients received the lower transthoracic line. The upper transthoracic line was associated with significantly lower incidence of catheter migration (1% vs 14%) and this held by multivariable logistic regression, adjusting for age and duration of the line (P = 0.003). There was no difference in the rate of other complications including bleeding. CONCLUSIONS: The upper transthoracic line is associated with significantly lower incidence of catheter migration and offers a more optimum position for central access following cardiac surgery.

Effect of thyroid hormone on cardiac function following orthotopic heart transplantation in piglets.

Studies in adult HT have demonstrated improved cardiac function in the recipient following administration of T3 to the donor. The purpose of this experiment was to assess the effects of T3 on the function of the immature donor heart following HT in a piglet model. A total of 32 piglets were divided into 16 donors and 16 recipients. Following creation of brain death, half of the donor piglets were randomized to receive three doses of T3 (0.2 µg/kg) along with hydrocortisone (1 mg/kg). The donor hearts were then transplanted into the recipient piglets on CPB. Duration of survival off CPB, inotrope score, and EF of heart following CPB were evaluated. There were no differences between the two groups in age, weight, pre-brain death EF, T3 levels, and CPB times. Post-CPB survival times were inversely related to the ischemic times in both groups (Pearson r=-0.80, P<.001), and this relationship was not influenced by T3. There was no difference in inotrope score, EF, or biochemical assessment between the two groups. Administration of T3 in combination with hydrocortisone to the brain-dead donor confers no beneficial effect on myocardial function or survival following HT in a piglet model.

Clinical evaluation of a radio-protective cream for the hands of the pediatric interventional cardiologist.

OBJECTIVES: The aim of this study was to evaluate the effectiveness of UltraBLOX™ radiation attenuating hand cream during lengthy cardiac catheterization procedures in children. BACKGROUND: The hands of interventional cardiologists receive high doses of radiation due to their proximity to the X-ray beam. Radiation attenuating gloves have about a 26% attenuation rate, but reduce dexterity and tactile sensation. The UltraBLOX™ cream is a new FDA-approved X-ray attenuating cream that can be applied to the operator's hands for radio-protection. METHODS: Two nanoDot™ dosimeters were secured side by side on the dorsum of the operator's (n = 2) left hand close to the wrist. One dosimeter and the rest of the hand were covered with 0.2 mm layer of the cream. The other dosimeter was unshielded. Procedures were performed using 110 kVp fluoroscopy at 15 pulses/sec. The measurements were categorized into four groups dependent on the duration of the procedure. The patients in all four groups were well matched for age and size. RESULTS: Procedural and cumulative hand radiation doses were higher with longer procedural duration. The overall % attenuation by the cream was 39.7% (28.6-51.5) and was unaffected by the length of the procedure (median: 40.9% at 30 min and 41.4% at 180 min; P = 0.66) or the dose of radiation. The kappa statistic for interobserver agreement for good tactile sensitivity was 0.82. CONCLUSIONS: UltraBLOX™ cream provides a new option for radio-protection for the hands of interventional cardiologists without impairing tactile sensitivity. There was no decrease in attenuation up to 180 min. © 2016 Wiley Periodicals, Inc.

Feasibility and Safety of Unzipping Small Diameter Stents in the Blood Vessels of Piglets.

OBJECTIVES: This study sought to determine the feasibility and safety of unzipping small-diameter stents (SDS) in a growing animal model. BACKGROUND: SDS implanted to relieve stenosis of blood vessels in infants may result in refractory stenosis as the child grows. If stents can be longitudinally fractured-unzipped-then the target vessel can potentially be redilated to the eventual adult vessel diameter. METHODS: Fifty stents (diameter 4 to 7 mm) were implanted in 5 neonatal piglets (mean age and weight = 1.5 weeks and 3.4 kg). Pre-mounted coronary (CS) (n = 24), biliary (BS) (n = 14), nitinol (NS) (n = 3), and renal stents (RS) (n = 9) were implanted in pulmonary arteries (n = 13), systemic arteries (n = 25), and systemic veins (n = 12). Three months later (median weight = 32 kg), unzipping was attempted by dilating the stents. RESULTS: All CS and RS unzipped at twice their nominal diameter with <20% shortening. None of the NS unzipped. The BS shortened the most (∼40%), with only 69% of the stents unzipping. Stainless steel CS and RS with an open cell design were significant predictors (p ≤ 0.01) for unzipping. On histopathology, unzipping of the BS caused the most medial dissection and vessel wall injury, while unzipping of the CS caused the least. CONCLUSIONS: Unzipping of small-diameter CS and RS implanted in systemic and pulmonary vessels is more feasible than the BS and NS. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.

Superior Vena Cava Reconstruction for Treatment of Chylothorax Resulting From Thrombosis of Superior Vena Cava in Young Infants.

BACKGROUND: Thrombosis and occlusion of the superior vena cava (SVC) can cause massive chylothorax resulting in significant morbidity and mortality among young infants. Medical therapy is often unsuccessful. We report a new surgical technique that entails open thrombectomy and reconstruction of the SVC and innominate vein to treat this condition. METHODS: The charts of 4 consecutive infants with chylothoraces refractory to conservative management were reviewed. The operations were performed on cardiopulmonary bypass without myocardial arrest. The SVC and innominate veins were incised open, and thrombectomy was performed. This was followed by homograft patch reconstruction of both the veins. RESULTS: The infants were aged between 5 weeks to 4 months and had an average weight of 4 kg. All of them had hypoalbuminemia and evidence of hypercoagulable state. After surgical intervention, 3 had complete relief of SVC obstruction. Two of the 3 patients had complete resolution of chylous effusion, and the third patient had a significant decrease in chest tube drainage (70%) by the end of 1 week. The fourth patient had recurrence of high drainage after an initial improvement, and a subsequent angiogram demonstrated stenosis of the SVC without thrombosis. The chest tube drainage finally resolved after balloon angioplasty. CONCLUSIONS: Thrombotic occlusion of the SVC can result in chylothorax that is often not amenable to medical therapy. This is associated with significant loss of proteins and hypercoagulable state. A complete surgical relief of SVC obstruction by open thrombectomy and venoplasty can result in dramatic decrease in chylous output.

Unzipping of small diameter stents: an in vitro study.

OBJECTIVE: The purpose of this study was to determine if small-diameter stents can be unzipped in vitro. BACKGROUND: Small-diameter stents can relieve stenosis in infant blood vessels. As the child grows, refractory stenosis may result. If an implanted stent can be intentionally fractured along its length-"unzipped," it can be redilated to the eventual adult vessel diameter. METHODS: Stents of diameters ≤6 mm were dilated using angioplasty balloons until they fractured. The change in length-diameter (dL/dD ratio), and the yield-point-force (σy ) for each stent was calculated. RESULTS: Thirty-four coronary (CS), 11 biliary, and 10 nitinol peripheral stents (median diameter = 4, 5, and 6 mm; range = 2.75-4.5, 4-6, 6 mm, respectively) were tested. Stainless-steel (SS) CS unzipped predictably at twice their nominal diameter with minimal shortening (n = 24, median dL/dD = 0.4). Nitinol stents fractured in a disorganized fashion. The remaining stents unzipped, had disorganized fractures, and shortened significantly (dL/dD>1). A dL/dD ratio of<1 had a strong, positive correlation with the ability to unzip (Pearson rho = 0.94). By multivariate regression analysis, SS alloy, and closed-cell design were found to be significant predictors (P < 0.05) for unzipping. Optimal cut-off points for stents to unzip included, strut-thickness = 112 µm, alloy-density = 7.7 g/cm(3) , dL/dD ratio = 0.12 and σy = 108Mpa (Youden's index = 0.8, 0.4, 0.8, and 0.5, respectively). CONCLUSIONS: Stainless-steel, coronary stents of a closed-cell design unzip at twice their nominal diameter without significant shortening when serially dilated. This study may encourage the implantation of small stents in infant blood vessels and aid in selection of appropriate stent type.

17Beta-estradiol confers a protective effect against transforming growth factor-beta2-induced cataracts in female but not male lenses.

Transforming growth factor-beta2 (TGF-beta2) induces anterior subcapsular cataracts, with a marked increase in cytoskeletal and extracellular matrix proteins, such as alpha-smooth muscle actin (alphaSMA). It has been shown that 17beta-estradiol (E2) can prevent TGF-beta2-induced cataracts in lenses from ovariectomized female rats. The purpose of the current study was to extend this finding by testing whether E2 can prevent TGF-beta2-induced cataracts and inhibit the induction of alphaSMA gene expression in normal male and normal, non-ovariectomized female rats.Sex-specific differences were observed in 17-week-old rat lenses incubated in 0.15 ng ml(-1) TGF-beta2 and in 10(-8)M E2 plus TGF-beta2. TGF-beta2 induced approximately twice as many anterior subcapsular plaques and 1.5 times the level of alphaSMA transcripts in male lenses compared to female lenses. Notably, E2 inhibited plaque formation and the induction of alphaSMA transcripts in female rat lenses but not in male rat lenses. E2 also inhibited the induction of alphaSMA in TGF-beta2-incubated lenses from ovariectomized female rats.E2 prevented lens opacification and the induction of alphaSMA gene expression in female, but not male, lenses. This sex-specific difference may have implications for studies on the therapeutic use of estradiol for treatment of secondary cataract.

Matrix metalloproteinases are down-regulated in rat lenses exposed to oxidative stress.

Matrix metalloproteinases are important biological effectors of tissue remodelling. Increased MMP expression occurs during injury, inflammation, cellular transformation, and oxidative stress. Oxidative stress in the lens, a causal factor in cataractogenesis, has been shown to induce MMP secretion. The objective of this study was to assess the expression of MMPs and their regulators in an oxidative stress model of cataract, where epithelial cell death and cortical fibre cell swelling occurs in rat lenses after exposure to riboflavin, oxygen, and light. Two time points (4 and 7 hr of exposure) were chosen in order to compare transparent lenses with partially opaque lenses. MMP activity, protein, and mRNA levels were measured. The results show that MMP-2, MMP-9, MT1-MMP, and MT3-MMP are down-regulated by oxidative stress and that the down-regulation is most likely due to reduced gene transcription. In contrast, genes for catalase, glutathione peroxidase, and GAPDH are essentially unaffected, while beta-actin mRNA and protein levels are markedly increased at both time points. The down-regulation of MMPs occurs in lenses still seemingly transparent after 4 hr of exposure, indicating that reduced MMP activity is a relatively early response to the oxidative stress. Moreover, in our model system, MMP inhibition, not induction, is associated with cataractogenesis.