Controlled contrast transcranial Doppler and arterial blood gas analysis to quantify shunt through patent foramen ovale.

BACKGROUND AND PURPOSE: A right-to-left shunt can be identified by contrast transcranial Doppler ultrasonography (c-TCD) at rest and/or after a Valsalva maneuver (VM) or by arterial blood gas (ABG) measurement. We assessed the influence of controlled strain pressures and durations during VM on the right-to-left passage of microbubbles, on which depends the shunt classification by c-TCD, and correlated it with the right-to-left shunt evaluation by ABG measurements in stroke patients with patent foramen ovale (PFO). METHODS: We evaluated 40 stroke patients with transesophageal echocardiography-documented PFO. The microbubbles were recorded with TCD at rest and after 4 different VM conditions with controlled duration and target strain pressures (duration in seconds and pressure in cm H2O, respectively): V5-20, V10-20, V5-40, and V10-40. The ABG analysis was performed after pure oxygen breathing in 34 patients, and the shunt was calculated as percentage of cardiac output. RESULTS: Among all VM conditions, V5-40 and V10-40 yielded the greatest median number of microbubbles (84 and 95, respectively; P<0.01). A significantly larger number of microbubbles were detected in V5-40 than in V5-20 (P<0.001) and in V10-40 than in V10-20 (P<0.01). ABG was not sensitive enough to detect a shunt in 31 patients. CONCLUSIONS: The increase of VM expiratory pressure magnifies the number of microbubbles irrespective of the strain duration. Because the right-to-left shunt classification in PFO is based on the number of microbubbles, a controlled VM pressure is advised for a reproducible shunt assessment. The ABG measurement is not sensitive enough for shunt assessment in stroke patients with PFO.

Baerveldt aqueous shunt implantation into the ciliary sulcus

Purpose: Aqueous shunt implantation into the anterior chamber is associated with corneal decompensation in up to a third of eyes. Intracameral tube position may affect corneal endothelial cell loss. The authors set out to examine the efficacy and safety of Baerveldt shunt implantation into the ciliary sulcus combined with surgical peripheral iridectomy (SPI). Methods: One hundred eyes prospectively underwent Baerveldt shunt implantation into the cilliary sulcus combined with SPI, leaving a short intracameral tube length (1-2mm). Pre and post operative measures recorded included patient demographics, visual acuity, IOP, number of glaucoma medications (GMs) and all complications. Pre-existing corneal decompensation was recorded. Success was defined as IOP≤21mmHg and 20% reduction in IOP from baseline with or without GMs. Results: Mean age was 65.4 years (±20.4years). Mean follow-up was 10.8 months. Preoperatively IOP was 25.7mmHg (± 9.9mmHg), GMs were 2.9 (±1.2) and VA was 0.4 (±0.3). At one year postoperatively there was a significant drop in IOP (mean= 13.3mmHg (± 5.0mmHg); p<0.001) and number of GMs (mean= 1.3 (±1.4); p<0.001); and no significant change in VA (mean= 0.4 (±0.3); p=0.93). The success rate at one year was 83%. Complications were minor and non sight threatening (10%), there were no cases of postoperative corneal decompensation, tube blockage or iris/corneal-tube contact. Conclusions: The results demonstrate that placement of Baerveldt shunts into the ciliary sulcus with SPI is a safe and efficacious method of IOP reduction in comparison with standard shunt positioning in the anterior chamber. The intracameral tube position combined with SPI avoided tube-iris contact and corneal decompensation. Sulcus placement of aqueous shunts should be considered in pseudophakic eyes.

Modified Blalock Taussig shunt: a not-so-simple palliative procedure.

OBJECTIVES: Thirty-two consecutive isolated modified Blalock Taussig (BT) shunts performed in infancy since 2004 were reviewed and analysed to identify the risk factors for shunt intervention and mortality. METHODS: Sternotomy was the only approach used. Median age and weight were 10.5 (range 1-74) days and 2.9 (1.9-4.4) kg, respectively. Shunt palliation was performed for biventricular hearts (Tetralogy of Fallot/double outlet right ventricle/transposition of great arteries_ventricular septal defect_pulmonary stenosis/pulmonary atresia_ventricular septal defect/others) in 21, and univentricular hearts in 11, patients. Hypoplastic left heart syndrome patients were excluded. Two procedures required cardiopulmonary bypass. Median shunt size was 3.5 (3-4) mm and median shunt size/kg body weight was 1.2 (0.9-1.7) mm/kg. Reduction in shunt size was necessary in 5 of 32 (16%) patients. RESULTS: Three of 32 (9%) patients died after 3 (1-15) days due to cardiorespiratory decompensation. Lower body weight (P = 0.04) and bigger shunt size/kg of body weight (P = 0.004) were significant risk factors for mortality. Acute shunt thrombosis was observed in 3 of 32 (9%), none leading to death. Need for cardiac decongestive therapy was associated with univentricular hearts (P < 0.001), bigger shunt size (P = 0.054) and longer hospital stay (P = 0.005). Twenty-eight patients have undergone a successful shunt takedown at a median age of 5.5 (0.5-11.9) months, without late mortality. CONCLUSIONS: Palliation with a modified BT shunt continues to be indicated despite increased thrust on primary corrective surgery. Though seemingly simple, it is associated with significant morbidity and mortality. Effective over-shunting and acute shunt thrombosis are the lingering problems of shunt therapy.

Modified Blalock-Taussig shunt with compensatory properties.

Determination of the proper length of the tubular prosthesis is a major issue when performing a systemic-pulmonary artery shunt. The procedure is simplified by using a prosthesis with accordionlike properties. This was demonstrated in 7 consecutive infants with complex congenital heart defects, in whom systemic-pulmonary artery shunts were placed without early or late complications.

Surgical outcomes of Baerveldt aqueous shunt implantation versus combined phacoemulsification and Baerveldt aqueous shunt implantation

Purpose: To examine the efficacy and safety of Baerveldt shunt (BS) implantation compared to combined phacoemulsification and Baerveldt shunt implantation (PBS). This study was designed to detect a difference in IOP reduction of 20% (~4mmHg) between groups with 90% power. Methods: Sixty patients with medically uncontrolled glaucoma, prospectively underwent either or BS implantation with phacoemulsification (Group PBS; n=30) or BS implantation alone (group BS; n=30, pseudophakic eyes only). Groups were matched for age, glaucoma subtype and length of follow-up. Pre and post-operative measures recorded included patient demographics, visual acuity, IOP, number of glaucoma medications (GMs) and all complications. Success was defined as IOP≤21mmHg and 20% reduction in IOP from baseline with or without GMs. Results: Age of PBS and BS groups was 61 vs 62 years respectively (p=0.72*). There were no significant differences in preoperative baseline characteristics: PBS vs PB, mean IOP =25.5mmHg (standard deviation (SD); ±10.3mmHg) vs 26.1mmHg (SD ±10.6mmHg), p=0.81*; mean GMs=3.0 (SD ±1.1) vs 3.1 (SD ±1.0), p=0.83*; mean VA=0.3 vs 0.3, p=0.89*. At year one there were no significant differences observed between groups in post-operative IOP, GMs or VA, mean IOP =14.1mmHg (SD ±5.4mmHg) vs 11.5 mmHg (SD ±4.2mmHg), p=0.12*; mean GMs=1.6 (SD ±1.4) vs 1.1 (SD ±1.1), p=0.23*; mean VA=0.5 vs 0.4, p=0.46*. Complication rates were similar between the two groups (7% vs 14%). Success rate was lower in eyes with PBS (71%) than with BS (88%), however this did not reach statistical significance (p=0.95, log-rank test). * two-sample t-test Conclusions: There were no significant differences at year one in success or complication rates between PBS and BS groups suggesting that simultaneous phacoemulsification does not have a marked (difference of >4mmHg) effect on tube function. IOP reduction and success were less in the PBS group, a larger sample (n=120) would be required to investigate if there is a 10% difference in IOP reduction between groups, however it is unclear if this would be a clinically significant difference to justify separate surgeries.

Visualization of aqueous shunt position and patency using anterior segment optical coherence tomography.

PURPOSE: To describe the use of anterior segment optical coherence tomography (AS-OCT) to clarify the position and patency of aqueous shunt devices in the anterior chamber of eyes where corneal edema or tube position does not permit a satisfactory view. DESIGN: Noncomparative observational case series. METHODS: Four cases are reported in which aqueous shunt malposition or obstruction was suspected but the shunt could not be seen on clinical examination. The patients underwent AS-OCT to identify the position and patency of the shunt tip. RESULTS: In each case, AS-OCT provided data regarding tube position and/or patency that could not be obtained by slit-lamp examination or by gonioscopy that influenced management. CONCLUSIONS: AS-OCT can be used to visualize anterior chamber tubes in the presence of corneal edema that precludes an adequate view or in cases where the tube is retracted into the cornea. In such cases, AS-OCT is useful in identifying shunt patency and position, which helps guide clinical decision making.

Surgical outcomes of deep sclerectomy versus Baerveldt aqueous shunt implantation following initial failed deep sclerectomy

Purpose: To examine the efficacy and safety of repeat deep sclerectomy (DS) versus Baerveldt shunt (BS) implantation as second line surgery following failed primary DS. Methods: Fifty one patients were prospectively recruited to undergo BS implantation following failed DS and 51 patients underwent repeat DS, for which data was collected retrospectively. All eyes had at least one failed DS. Surgical success was defined as IOP≤21mmHg and 20% reduction in IOP from baseline. Success rates, number of glaucoma medications (GMs), IOP, and complication rates were compared between the two groups at year 1, post-operatively. Results: Mean age, sex and the proportion of glaucoma subtypes were similar between groups. Preoperatively IOP was significantly lower in DS group vs BS group (18.8mmHg vs 23.8mmHg, p<0.01, two sample t-test). Postoperatively IOP was significantly higher in DS group than BS group (14.6mmHg vs 12.0mmHg, p<0.01, two-sample t-test). In the DS group, 47% of eyes did not achieve 20% reduction in IOP from baseline, as a result the success rates were significantly lower in eyes with DS (51%) than in eyes with BS (88%) (p=0.02, log-rank test). Preoperatively the number of GMs used in DS and BS groups were similar (2.2 vs 2.7 p=0.02, two sample t-test). Postoperatively there remained no significant difference in GMs between groups (0.9 vs 1.1, p= 0.58, two sample t-test). Complication rates were similar between the two groups (12% vs 10%). Conclusions: Baerveldt tube implantation was more effective in lowering IOP than repeat deep sclerectomy in eyes with failed primary DS, at year one. Complications were minor and infrequent in both groups

Early transjugular intrahepatic portosystemic shunt in cirrhotic patients with acute variceal bleeding: a systematic review and meta-analysis of controlled trials.

INTRODUCTION: There is conflicting evidence on the benefit of early transjugular intrahepatic portosystemic shunt (TIPSS) on the survival of patients with acute variceal bleeding (AVB). AIM: To assess the effect of early TIPSS on patient prognosis. MATERIALS AND METHODS: We carried out a meta-analysis of trials evaluating early TIPSS in cirrhotic patients with AVB. RESULTS: Four studies were included. Early TIPSS was associated with fewer deaths [odds ratio (OR)=0.38, 95% confidence interval (CI)=0.17-0.83, P=0.02], with moderate heterogeneity between studies (P=0.15, I=44%). Early TIPSS was not significantly associated with fewer deaths among Child-Pugh B patients (OR=0.35, 95% CI=0.10-1.17, P=0.087) nor among Child-Pugh C patients (OR=0.34, 95% CI=0.10-1.11, P=0.074). There was no heterogeneity between studies in the Child-Pugh B analysis (P=0.6, I=0%), but there was a high heterogeneity in the Child-Pugh C analysis (P=0.06, I=60%). Early TIPSS was associated with lower rates of bleeding within 1 year (OR=0.08, 95% CI=0.04-0.17, P<0.001) both among Child-Pugh B patients, (OR=0.15, 95% CI=0.05-0.47, P=0.001) and among Child-Pugh C patients (OR=0.05, 95% CI=0.02-0.15, P<0.001), with no heterogeneity between studies. Early TIPSS was not associated with higher rates of encephalopathy (OR=0.84, 95% CI=0.50-1.42, P=0.5). CONCLUSION: Cirrhotic patients with AVB treated with early TIPSS had lower death rates and lower rates of clinically significant bleeding within 1 year compared with patients treated without early TIPSS. Additional studies are required to identify the potential risk factors leading to a poor prognosis after early TIPSS in patients with AVB and to determine the impact of the degree of liver failure on the patient's prognosis.

Extracorporeal membrane oxygenation support after heart explantation: a proposal on how to deal with hyperacute rejection of heart transplant

Purpose: In extreme situations, such as hyperacute rejection of heart transplant or major bleeding per-operating complications, an urgent heart explantation might be the only means of survival. The aim of this experimental study was to improve the surgical technique and the hemodynamics of an Extracorporeal Membrane Oxygenation (ECMO) support through a peripheral vascular access in an acardia model. Methods: An ECMO support was established in 7 bovine experiments (59±6.1 kg) by the transjugular insertion to the caval axis of a self-expanded cannula, with return through a carotid artery. After baseline measurements of pump flow and arterial and central venous pressure, ventricular fibrillation was induced (B), the great arteries were clamped, the heart was excised and right and left atria remnants, containing the pulmonary veins, were sutured together leaving an atrial septal defect (ASD) over the cannula in the caval axis. Measurements were taken with the pulmonary artery (PA) clamped (C) and anastomosed with the caval axis (D). Regular arterial and central venous blood gases tests were performed. The ANOVA test for repeated measures was used to test the null hypothesis and a Bonferroni t method for assessing the significance in the between groups pairwise comparison of mean pump flow. Results: Initial pump flow (A) was 4.3±0.6 L/min dropping to 2.8±0.7 L/min (P B-A= 0.003) 10 minutes after induction of ventricular fibrillation (B). After cardiectomy, with the pulmonary artery clamped (C) it augmented not significantly to 3.5±0.8 L/min (P C-B= 0.33, P C-A= 0.029). Finally, PA anastomosis to the caval axis was followed by an almost to baseline pump flow augmentation (4.1±0.7 L/min, P D-B= 0.009, P D-C= 0.006, P D-A= 0.597), permitting a full ECMO support in acardia by a peripheral vascular access. Conclusions: ECMO support in acardia is feasible, providing new opportunities in situations where heart must urgently be explanted, as in hyperacute rejection of heart transplant. Adequate drainage of pulmonary circulation is pivotal in order to avoid pulmonary congestion and loss of volume from the normal right to left shunt of bronchial vessels. Furthermore, the PA anastomosis to the caval axis not only improves pump flow but it also permits an ECMO support by a peripheral vascular access and the closure of the chest.

Actualités diagnostiques et thérapeutiques dans le domaine de l'encéphalopathie hépatique [Hepatic encephalopathy: recent developments].

Hepatic encephalopathy is a neurological syndrome occurring in patients with liver failure or in those with a large porto-systemic shunt. In cirrhotic patients, the current classification comprises covert and overt encephalopathy. Diagnosis of covert encephalopathy requires sensitive tests. Lactulose and rifaximin are the two leading therapeutic options. Rifaximin is efficacious for maintaining remission from hepatic encephalopathy. Liver transplantation should be discussed in cirrhotic patients with encephalopathy.

Approche des oedèmes du membre supérieur liés à une occlusion de la veine sous-clavière située en aval d'une fistule artério-veineuse [Approach to upper limb edema secondary to subclavian vein occlusion situated distal to an arteriovenous fistula]

AIM OF THE STUDY: To analyse the course of upper limb edema in patients with an arteriovenous fistula used for dialysis and to analyse the available therapeutic options. STUDY DESIGN: Retrospective study of patients with this type of edema, who were treated in our institution from 1992 to 1996. PATIENTS AND METHODS: Seven consecutive patients with an arterioveinous fistula treated for edema of the upper extremity, were reviewed. The fistula was created at the elbow in 6 patients and at the forearm in 1. The edema appeared immediately after operation in 4 patients and after a delay in 3 patients. Stenosis (3 patients) or occlusion (2 patients) of the subclavian vein was documented in 5 patients who were investigated by angiography. RESULTS: The edema regressed spontaneously in 4 patients because collaterals developed in 3 patients, and the fistula thrombosed in 1 patient. Surgical intervention allowed regression of the edema in the other 3 patients: excessive output of the fistula was reduced in 2 patients and an axillojugular bypass was performed in 1 patient. The fistula remained effective in 6 patients. Another fistula was performed on the contralateral arm in 1 patient. CONCLUSION: Non-operative management is recommended in patients who develop edema immediately after creation of the fistula, because spontaneous regression is likely. Measures aimed at reducing the output of the fistula or enhancing the venous capacities of the arm are required when edema appears at a later stage. The fistula can be saved in the majority of cases.

Anomalies et complications vasculaires dans les drusen du nerf optique [Vascular anomalies and complications of optic nerve drusen]

BACKGROUND: Drusen of the optic disc are associated with slowly progressive optic neuropathy, characterized by accumulation of acellular laminated concretions in the prelaminar portion of the optic nerve. Papillary hemorrhages and vascular shunts have been reported with disc drusen but their frequency and clinical significance is not well known. METHODS: Retrospective study of fundus photographs of 116 patients with disc drusen referred to the National Hospital for Neurology and Neurosurgery, London, between 1965 and 1991. RESULTS: Hemorrhages were found in 23 eyes from 16/116 (13.8%) patients. Most cases (68.8%, 11/16 cases) occurred in patients with buried drusen, and most hemorrhages were deeply located. Vascular shunts were present in 6.9% (8/116 cases), most frequently in patients with exposed drusen (6/8 cases), most being of the venous type (7/8 cases). DISCUSSION: Vascular anomalies are not rare in disc drusen, as 20.7% (24/116 cases) of our patients presented either disc hemorrhages or shunt vessels. Their presence supports the hypothesis of the slowly progressive nature of disc drusen and the more advanced stage of optic neuropathy in such eyes.

Neuro-developmental follow-up of neonates treated with magnesium sulfate for persistent pulmonary hypertension

Rapport de synthèse : DEVENIR NEURO-DEVELOPPEMENTAL DE NOUVEAU-NES TRAITES PAR DU SULFATE DE MAGNESIUM POUR UNE HYPERTENSION PULMONAIRE PERSISTANTE L'hypertension pulmonaire persistante du nouveau-né (HTPP) est un trouble de l'adaptation post-natale de la circulation pulmonaire caractérisé par une défaillance de la diminution normale des résistances vasculaires pulmonaires, accompagné d'un shunt droite-gauche, résultant en une hypoxémie profonde. C'est une pathologie sévère nécessitant des soins intensifs avec un risque augmenté de handicaps neurologiques chez les survivants. Le traitement de l'HTPP du nouveau-né inclut une ventilation mécanique ainsi que différents agents pharmacologiques pour dilater les vaisseaux pulmonaires, dont le sulfate de magnésium (MgSO4) à hautes doses par voie intraveineuse et le monoxyde d'azote par voie inhalée (iN0). Le MgSO4 est une alternative thérapeutique de l'HTPP du nouveau-né avec peu d'effets secondaires et une mortalité basse. Il a aussi été démontré que le MgSO4 est un traitement de l'HTPP du nouveau-né autant efficace que le iN0 et moins coüteux. Des études sur le suivi neuro-développemental de nouveau-nés avec HTPP traités selon différentes méthodes ont été publiées reportant des taux élevés de handicaps majeurs et mineurs. Plus récemment, des études de suivi après traitement par iN0 ont montré des taux plus bas qu'avec des traitements antérieurs. Le devenir neuro-développemental àlong terme d'enfants traités avec du MgSO4 n'a pas été documenté. Le but de cette étude est de décrire le développement des enfants qui ont présenté une HTPP traitée seulement avec du MgS04, de reporter l'incidence de handicaps majeurs et mineurs, et de les comparer à un groupe contrôle d'enfants sains du même âge ainsi qu'aux données de la littérature. La population consiste en 33 nouveau-nés traités pour une HTPP avec seulement du MgSO4 (groupe étude) et 32 nouveau-nés à terme sains (groupe contrôle). Un suivi neurodéveloppemental standardisé et approfondi a été effectué aux âges clés de 18 mois et 5 ans. Les taux de handicaps majeurs à 18 mois et 5 ans dans le groupe étude étaient de 6% et 11,4% respectivement, et de 0% aux deux âges dans le groupe contrôle. Les taux de handicaps mineurs aux mêmes âges étaient de 3% et 26,9% pour le groupe étude, et de 0% et 26,1% pour le groupe contrôle. Les quotients développementaux moyens à 18 mois étaient de 106,6 (DS 1,6) dans le groupe étude et de 118,3 (DS 1,0) dans le groupe contrôle (P < 0,001). L'index général intellectuel en âge préscolaire était de 112.6 (DS 3.7), respectivement de 119.3 (DS 3.1 ), sans différence significative entre les deux groupes. A 18 mois, les taux de handicaps majeurs et mineurs dans les groupes études et contrôle étaient de 6% et 3%. Dans la littérature, des taux entre 0% et 33% ont été décrits. A cet âge, il y avait une différence significative pour tous les scores du test de Griffiths, mëme en tenant compte du status socio-économique de la famille. Ceci suggère un léger retard du développement global et non une altération spécifique. Ces différences n'étaient plus significatives en âge préscolaire, suggérant un rattrapage développemental. Le taux de handicaps majeurs en âge préscolaire pour le groupe étude était de 11.5%, sans aucune infirmité motrice cérébrale. Ces résultats correspondent à ceux d'études de suivi après d'autres traitements jusqu'à l'âge de 24 mois avec des taux variant de 0% à 15%. Le taux de handicaps mineurs était de 26.9% dans le groupe étude et de 26.1% dans le groupe contrôle, sans différence significative entre les deux groupes. L'incidence de handicaps mineurs dans le groupe étude était plutôt élevée en comparaison aux données de la littérature (6 à 22% à 6 ans). Une explication possible est que nous avons considéré des problèmes de langage et de comportement comme handicaps mineurs. Ceci suggère une différence méthodologique et non une plus mauvaise issue dans nos deux groupes. Les évaluations cognitives des enfants des deux groupes se trouvaient dans la norme, ce qui est aussi le cas dans la littérature. En conclusion, cette étude longitudinale non randomisée d'enfants traités avec du MgSO4 seul pour une HTPP sévère ne montre pas de conséquences sur le devenir neuro-développemental à long terme. Cette étude le démontre pour la première fois. Malgré le fait que iN0 soit le traitement actuellement recommandé pour l'HTPP du nopuveau-né, le MgSO4 reste largement utilisé, en particulier dans des pays en voie de développement. L'absence de complications neuro-développementales majeures à long terme permet de considérer l'administration du MgSO4 pour le traitement de l'HTPP du nouveau-né en cas de non réponse ou d'inaccessibilité au iNO.