Bicuspid pulmonary valve with atrial septal defect leading to pulmonary aneurysm

Pulmonary artery aneurysms are rare. We describe 2 adult patients with pulmonary artery aneurysm with normal pulmonary pressure associated with bicuspid pulmonary valve and atrial septal defect. One patient presented with moderate pulmonary valve stenosis and was treated with open surgery; the other patient had a small atrial septal defect and mild pulmonary valve insufficiency and is periodically still being evaluated. Hemodynamic alterations associated with a pulmonary artery aneurysm are described; the influence of additional volume overload and intrinsic wall abnormalities in pulmonary valvular lesions as potential triggers for the development of these aneurysms are analyzed and therapeutic strategies are discussed.     

Management of acute intraoperative cerebrospinal fluid leaks

Incidental durotomy in spinal surgery has been reported with incidences varying between 1 and over 16%, depending on the type of surgery and the region of the spine. When a dural tear occurs, immediate and meticulous repair is advised in order to minimize the risk of complications secondary to persistent leakage of cerebrospinal fluid (CSF). These complications include intracranial hypotension, pseudomeningocele formation and the development of a CSF fistula with secondary wound infection and meningitis. Most dural tears are caused during biting actions by Kerrison rongeurs, and dural adhesions, dural redundancy and thinned dura are known risk factors. Accurate visualization and thorough preparation of the surgical field are key steps in dural tear repair. Those tears that are amenable to it should be carefully sutured. Large defects may require a patch of dural substitute to be sewed in. Autologous fat has proven to be useful as onlay or plugin graft. The use of fibrin glue has become a widespread practice and its effectiveness as an adjunct to primary suturing and graft constructions has been well demonstrated. Hydrogel sealants and collagen matrix onlay grafts have become available to the surgeon as additional tools in dural tear repair. However, primary suturing — if possible — is still considered to be the most effective way of reducing the chance of persistent CSF leakage. Tight closure of the fascial layer is imperative. After lumbar durotomy repair, bed rest is advised. Postoperative lumbar or ventricular CSF drainage can also help as an additional protective measure. While numerous measures and tools are available, the key message is that the surgeon confronted with a dural tear should take his time and apply all intraoperative and postoperative means required to secure watertight closure.     

Surgical epicardial left ventricular lead versus coronary sinus lead placement in biventricular pacing.

OBJECTIVE: Biventricular pacing has demonstrated improvement in cardiac function in treating congestive heart failure (CHF). Two different operative strategies (coronary sinus vs. epicardial stimulation) for left ventricular (LV) pacing were compared. METHODS: Since April 1999, a total of 86 patients (pts, age: 63+/-10 years) with depressed systolic LV function (mean ejection fraction 24+/-9%), left bundle-branch-block (mean QRS 182+/-22 ms) and congestive heart failure NYHA III or higher were enrolled. For biventricular stimulation coronary sinus (CS) leads were placed in 79 pts. Nine of these devices were converted to surgical epicardial LV-leads, because of CS-lead failure. In 7 patients epicardial LV-leads were initially implanted surgically, accounting for a total of 16 pts with surgical placed epicardial steroid-eluting LV-leads. For these, a limited left-lateral thoracotomy (7+/-4 cm) was used. Thirty-three (38%) pts had an indication for a defibrillator. The mean follow-up time was 16.4+/-15.4 months (0.1-45 months), representing 107.1 patient-years. RESULTS: In the biventricular pacing mode, QRS duration decreased to 143+/-16 ms (P<0.001). Threshold capture of the CS-leads increased significantly compared to surgically placed epicardial leads (18 month control: 2.2+/-1.4V/0.5 ms vs. 0.7+/-0.3V/0.5 ms), which had no increase in threshold (P<0.001). At the 18 month follow-up 7 CS-leads had a threshold of >4V/0.5 ms vs. epicardial leads which were under 1.1V/0.5 ms, except for one (1.8V/0.5 ms). After CS-lead implantation 25 LV-lead related complications occurred, (failed implantation, CS-dissection, loss of pacing capture, diaphragm stimulation or lead dislodgment), vs. one dislodgement after surgical epicardial lead placement (P<0.05). Correct lead positioning (obtuse marginal branch area) was achieved in all surgical epicardial placements but only in 70% with CS-leads (P<0.03). In the follow up period, 9 pts died (4 cardiac related). Heart transplantation was necessary in 4 pts due to deterioration of the cardiomyopathy. CONCLUSIONS: Surgical epicardial lead placement revealed excellent long-term results and a lower LV-related complication rate compared to CS-leads. Although, the approach via limited thoracotomy for biventricular pacing is associated with 'more surgery', it is a safe and reliable technique and should be considered as an equal alternative.     

Cytochrome P450 3A4 and P-glycoprotein Activity and Assimilation of Tacrolimus in Transplant Patients with Persistent Diarrhea

Renal transplant recipients suffering from persistent diarrhea have been repeatedly reported to have increased tacrolimus (Tac) trough levels. This study aimed to explore this phenomenon in detail in 15 renal transplant recipients with diarrhea, whose immunosuppression consisted of corticosteroids, mofetil mycophenolate and Tac. Both hepatic and intestinal CYP3A4 and PGP activity, important determinants of Tac bioavailability, were assessed, together with global CYP activity and investigations for gastrointestinal infection, function and morphology. Global CYP, CYP3A4, PGP and trough/dose levels of Tac were compared with diarrhea-free controls. In addition, a pharmacokinetic study of Tac was performed in 11 patients affected by diarrhea versus 9 controls. As expected, diarrhea was associated with increased Tac trough levels. An even stronger, significant increase of dose-normalized Tac levels was observed between 90 and 360 min after Tac intake. Time to peak concentration and drug half-life, however, were not altered. In addition, a concomitant decrease (+/-50%) of intestinal PGP activity was noticed in patients with diarrhea. For global CYP, CYP3A4 and hepatic PGP activity no such differences were noted. This pattern was not influenced by the specific cause of diarrhea. These data strongly suggest that persistent diarrhea is associated with an increased oral bioavailability of Tac.     

Carnosine as a protective factor in diabetic nephropathy: association with a leucine repeat of the carnosinase gene CNDP1

The risk of diabetic nephropathy is partially genetically determined. Diabetic nephropathy is linked to a gene locus on chromosome 18q22.3-q23. We aimed to identify the causative gene on chromosome 18 and to study the mechanism by which the product of this gene could be involved in the development of diabetic nephropathy. DNA polymorphisms were determined in 135 case (diabetic nephropathy) and 107 control (diabetes without nephropathy) subjects. The effect of carnosine on the production of extracellular matrix components and transforming growth factor-beta (TGF-beta) after exposure to 5 and 25 mmol/l d-glucose was studied in cultured human podocytes and mesangial cells, respectively. A trinucleotide repeat in exon 2 of the CNDP1 gene, coding for a leucine repeat in the leader peptide of the carnosinase-1 precursor, was associated with nephropathy. The shortest allelic form (CNDP1 Mannheim) was more common in the absence of nephropathy (P = 0.0028, odds ratio 2.56 [95% CI 1.36-4.84]) and was associated with lower serum carnosinase levels. Carnosine inhibited the increased production of fibronectin and collagen type VI in podocytes and the increased production of TGF-beta in mesangial cells induced by 25 mmol/l glucose. Diabetic patients with the CNDP1 Mannheim variant are less susceptible for nephropathy. Carnosine protects against the adverse effects of high glucose levels on renal cells.     

Use of single‐representative reverse‐engineered surface‐models for RSA does not affect measurement accuracy and precision

Implant migration can be accurately quantified by model‐based Roentgen stereophotogrammetric analysis (RSA), using an implant surface model to locate the implant relative to the bone. In a clinical situation, a single reverse engineering (RE) model for each implant type and size is used. It is unclear to what extent the accuracy and precision of migration measurement is affected by implant manufacturing variability unaccounted for by a single representative model. Individual RE models were generated for five short‐stem hip implants of the same type and size. Two phantom analyses and one clinical analysis were performed: “Accuracy‐matched models”: one stem was assessed, and the results from the original RE model were compared with randomly selected models. “Accuracy‐random model”: each of the five stems was assessed and analyzed using one randomly selected RE model. “Precision‐clinical setting”: implant migration was calculated for eight patients, and all five available RE models were applied to each case. For the two phantom experiments, the 95%CI of the bias ranged from ?0.28 mm to 0.30 mm for translation and ?2.3° to 2.5° for rotation. In the clinical setting, precision is less than 0.5 mm and 1.2° for translation and rotation, respectively, except for rotations about the proximodistal axis (<4.1°). High accuracy and precision of model‐based RSA can be achieved and are not biased by using a single representative RE model. At least for implants similar in shape to the investigated short‐stem, individual models are not necessary. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:903–910, 2016.

     

Surgical treatment of achilles tendon rupture: examination of strength of 3 types of suture techniques in a cadaver model

BACKGROUND: The mechanical properties of present-day percutaneous repairs of Achilles tendon ruptures are not known. MATERIAL AND METHODS: Artificially-created ruptures in 24 human cadaveric Achilles tendons were repaired with an open Bunnell repair, a percutaneous calcaneal tunnel or a percutaneous bone-anchor repair. In the open technique no.1 PDS-II absorbable suture material was used, and in the percutaneous techniques either no.1 PDS-II or no.1 Panacryl absorbable suture material was used. The specimens were tested in a materials testing machine until failure occurred. RESULTS: The common mode of failure was suture breakage in non-anchor repairs, and anchor pullout in anchor repairs. The average strength of the repairs varied from 166 N (SD 60) to 211 N (SD 30), with no differences between the techniques (p = 0.5). INTERPRETATION: Taking costs into account, the percutaneous calcaneal tunnel technique and the open technique are the methods of choice.     

Long-term reendothelialization of excimer laser-assisted nonocclusive anastomoses compared with conventionally sutured anastomoses in pigs

OBJECT: In contrast to conventional anastomosis methods, the excimer laser-assisted nonocclusive anastomosis (ELANA) technique involves a platinum ring and intima-adventitia apposition with a rim of medial and adventitial layers exposed to the bloodstream. The authors assessed the reendothelialization of porcine carotid arteries through ELANA compared with conventional anastomosis by using scanning electron microscopy. METHODS: In 28 pigs a bypass with one ELANA and one conventional anastomosis was made on the left common carotid artery. All patent anastomoses were evaluated intraoperatively with the aid of an ultrasonographic flowmeter and postoperatively by using scanning electron microscopy at 2 weeks, 2 months, 3 months, and 6 months thereafter. Twenty-four of 28 bypasses (48 of 56 end-to-side anastomoses) were fully patent at the time of evaluation. On scanning electron microscopic evaluation of the bypasses, all 48 patent anastomoses showed complete reendothelialization, including all 24 ELANAs in which the endothelium covered the rim and the laser-ablated edge completely. No endothelial difference was observed between conventional anastomoses and ELANAs, aside from the obvious anatomical differences like the platinum ring, which had been completely covered with endothelium. At 6 months postsurgery, remodeling of the ELANA was observed, leaving the ring covered with a layer of endothelium as the most narrow part of the anastomosis. CONCLUSIONS: In long-term experiments, ELANA allows reendothelialization comparable to that achieved with conventional anastomosis. Considering its nonocclusive and high-flow characteristics, the ELANA technique is preferable in cerebral revascularization procedures.