Digestive proteases and in vitro protein digestibility of feed ingredients for the Central American river turtle, Dermatemys mawii.

Functional characteristics of digestive proteases and in vitro digestibility of several protein sources were studied in hatchlings of Central American river turtles, Dermatemys mawii. Acidic and alkaline proteases from the stomach and intestines were used, and optimums for acidic proteases were registered at 55°C and pH 2, while alkaline proteases were found at 55°C and pH 9. Ten protein ingredients, both vegetable and animal sources, were explored by the pH-STAT method, only for alkaline proteases. The degree of hydrolysis was at its highest for squid meal and lowest for blood meal, while the total free amino acids level was at its highest for squid meal, and lowest for wheat gluten meal. Our results indicate that D. mawii has a broad capacity to digest both animal and vegetable sources, and suggests some ingredients more suitable to design artificial diets for this species.

Percutaneous mitral valve treatment.

Over the last decade a multitude of transcatheter technologies, many of them based on surgical mitral repair techniques, are being developed. This manuscript describes some of these technologies based on their mechanism of action.

Injection augmentation of arytenoids after partial laryngectomy: case series.

BACKGROUND: We undertook collagen injection laryngoplasty to achieve arytenoid augmentation in patients with dysphagia and persistent aspiration following partial laryngectomy, and we evaluated the efficacy of arytenoid augmentation in aiding neoglottic closure and ensuring airway safety. METHODS: Two patients with persistent swallowing impairment after partial laryngectomy were studied. Swallowing was evaluated using fibre-optic endoscopy, and modified barium swallow study. Collagen was then injected into the arytenoid mucosa to achieve neoglottic competence. RESULTS: The patients were followed up for up to two years. Both patients showed a marked improvement in neoglottic competence, as evaluated by fibre-optic and flexible endoscopy at three-month and one-year follow-up appointments. CONCLUSION: Arytenoid augmentation by injection laryngoplasty can be considered a safe and effective surgical tool for the treatment of dysphagia with persistent aspiration following partial laryngectomy.

Transcatheter heart valves for the treatment of aortic stenosis: state-of-the-art.

UNLABELLED: Degenerative aortic stenosis is the most frequent heart valve disease. As an alternative to surgical aortic valve replacement, several companies are working on the development of new prosthesis designed to be deployed by transcatheter approaches. Both transfemoral and transapical techniques are feasible, and initial trials in high-risk patients show good procedural outcomes and mid-term (up to 2 years) functionality. Two first-generation prosthesis (Edwards-SAPIEN and CoreValve Revalving System) are commercially available in Europe, and a number of other second-generation valves (with the capabilities of repositioning and retrievability) are under evaluation. Among them, the Sadra-Lotus Valve, The Direct Flow Medical valve and the Paniagua Heart Valve have published first-in-man results; the JenaValve and AorTx devices have also been temporarily implanted in humans. The development of repositionable and retrievable prosthesis with improved profile is mandatory, and it is the main focus of current projects. Not only technical improvements but also operators specialization and an optimal patient selection are essential to improve these initial RESULTS: Some procedural challenges need to be overcome prior to the expansion of these techniques to lower risk groups, and time is needed for detailed long-term outcomes and risk estimations. Only with a close collaboration among different specialists, basic researchers and the industry will the future development of transcatheter aortic implantation techniques be ensured.

Transcatheter aortic valve implantation and mitral valve repair: state of the art.

Surgical replacement of cardiac valves evolved significantly since its first use. Evolution of techniques and valves used was driven by the frequent complications encountered with surgically implanted valves. Transcatheter implantation of valves is a new technique which continues to be under investigation and promises to perform a task with less risk and potentially better outcome. In addition, new techniques are being developed to address minimizing mitral regurgitation. Progress in transcatheter valve implantation and catheter mitral annuloplasty is reviewed in this article.

Percutaneous closure of a left ventricular perforation post balloon mitral valvotomy.

The risk of left ventricular perforation is a rare but well-recognized complication of percutaneous double balloon mitral valvuloplasty that usually requires surgical bailout. We describe a case of left ventricular perforation with cardiac tamponade, caused by the propulsion of the balloons during balloon mitral valvotomy on an 86-year-old female with previous thoracotomies that was resolved using percutaneous coil embolization of the perforation. This approach to these types of complications, although unlikely to be of extensive use, will serve to expand the horizon of options in the field of interventions. Cathet. Cardiovasc. Intervent. 48:78-83, 1999.

Factors determining normalization of pulmonary vascular resistance following successful balloon mitral valvotomy.

Balloon mitral valvotomy (BMV) provides improvement in pulmonary vascular resistance (PVR) in patients with severe mitral stenosis. Its normalization, however, remains questionable. We evaluated PVR before, after BMV, and at follow-up in 37 patients who had a previous successful BMV. Patients were divided into 2 groups: group 1 had 21 patients with normalized PVR (<125 dynes/s/cm5) either after BMV or at follow-up, and group 2 had 16 patients with persistently abnormal PVR. Patients in group 2 were older than patients in group 1 (55+/-13 vs 43+/-14 years, p = 0.01) and had atrial fibrillation more frequently (10 [63%] vs 6 [29%], p = 0.04). Age, cardiac rhythm, mitral valve area, pulmonary bed gradient, pulmonary artery pressure, and PVR before the procedure were significant univariate predictors for normalization of PVR. Age, echocardiographic score, systolic pulmonary artery pressure, and mitral regurgitation were all independent determinants of normalization of PVR in a multivariate logistic regression model. We conclude that PVR failed to return to normal in 16 patients (43%) after successful BMV; this can be predicted by baseline clinical and hemodynamic parameters.

Catheter therapy for fontan baffle obstruction and leak, using an endovascular covered stent.

A 6 1/2-year-old (weight 20 kg) patient was found to have significant cavo-atrial obstruction and significant right-to-left shunt via multiple large fenestrations in the baffle, with oxygen saturation of 81% 3 1/2 yr after a fenestrated Fontan operation. In one session, this patient had undergone placement of a Palmaz stent at the cavo-atrial narrowing in order to increase anterograde venous return into the pulmonary artery. This was unsuccessful in improving the oxygen saturation because of the large leak in the baffle. Therefore, at a second catheterization session, two telescoping dacron-covered experimental vascular self-expanding stents were placed from the right atrial origin (distal to the hepatic veins) into the pulmonary artery connection delineated by the Palmaz stent, with complete reconstruction of the baffle and improvement in oxygen saturation to 95%.

Comparison of late results of balloon valvotomy in mitral stenosis with versus without mitral regurgitation.

Balloon mitral valvotomy (BMV) is safe and effective in patients with mitral stenosis (MS) and coexisting mild mitral regurgitation (MR). Influence of preexisting MR on late outcome of BMV is under evaluation. We included 77 patients without MR and 72 with MR in this study, and compared their immediate and late results in a mean follow-up of 33 +/- 24 months after BMV. Patients with coexisting MR were older and more frequently had significant valvular calcium and atrial fibrillation than patients without MR. After BMV, mitral valve gradient decreased, and cardiac output and mitral valve area by planimetry increased significantly (all p = 0.0001) in both groups. There was no difference in values of mitral valve gradient and cardiac output after BMV between the groups. Mitral valve area was significantly smaller in patients with preexisting MR. During follow-up, there were 11 patients (14%) in the group without MR and 24 (33%) in the group with MR developed cardiac events (p = 0.006). Cumulative event-free survival was 90% at the second year, 87% at the fourth year, and 69% at the sixth year, respectively, in the group without MR versus 78%, 62%, and 37%, respectively, in the group with MR (p = 0.0014). Cox regression showed that preexisting MR was a significant predictor for late cardiac events with a threefold increased hazard risk (p = 0.0025), but age, valvular calcium, echocardiographic score, and cardiac rhythm also played a culpable role. We conclude that preexisting MR is an important risk factor for poor, late outcome of BMV.

Non-surgical treatment of abdominal aortic aneurysms.

Percutaneous placement of an endovascular stent, with and without coils, in the treatment of large AAA in animal models is feasible, safe and effective. The covered stent sealed off AAA immediately after stent placement, however, it interrupted blood flow into arteries in the area covered by the stent. The uncovered stent prevented further expansion of the aneurysm and also significantly decreased the incidence of rupture. The long-term patency of branch arteries by the uncovered stent supported the possibility of safely using this approach in humans. Furthermore, either covered stent or uncovered stent with additional coils have the potential for treatment of acute aneurysm rupture or leaking. Most importantly, the aneurysm lumen in our model was gradually replaced by collagen after stent placement which further reduces the risk of aneurysm rupture: and this healing process was enhanced by the addition of coils. If proven safe and effective for humans as well, this technique has the potential for substantially reducing the morbidity and mortality associated with AAA.

A novel prognostic scoring system to predict late outcome after percutaneous balloon valvotomy in patients with severe mitral stenosis.

We developed a prognostic scoring system to predict the outcome of follow-up after balloon mitral valvotomy. The system incorporates seven variables before valvotomy: age, New York Heart Association class, fluoroscopic calcification, echocardiographic score, cardiac rhythm, mitral regurgitation, and mitral valve area. Each variable was coded with either 0 or 1 and a total score was between 0 and 7. The study included 150 patients with a mean follow-up of 33 +/- 24 months. In patients with scores of 0-1, 2-3, 4-5, and 6-7, the estimated cardiac event-free survival rate was 97%, 94%, 86%, and 68%, respectively, at 1 year; 95%, 88%, 74%, and 47%, respectively, at 3 years; and 92%, 82%, 61%, and 30%, respectively, 5 years after valvotomy (p = 0.0001). The hazard risk ratio for cardiac events was 1.7 times greater for every step up of the score (p = 0.0001). Our scoring system provides a simple but effective method to predict late outcome of balloon mitral valvotomy.

Percutaneous treatment of abdominal aortic aneurysm in a swine model: understanding the behavior of aortic aneurysm closure through a serial histopathological analysis.

BACKGROUND: Previous studies used covered stent grafts to treat abdominal aortic aneurysms; however, such devices block flow into aortic side branches. We used uncovered stents with and without additional embolization coils to treat abdominal aortic aneurysm in a swine model and examined serial histological changes in the aneurysms over a 6-month period. METHODS AND RESULTS: We examined aneurysms in 9 control and 9 treated pigs (5 received stents alone and 4 received stents and coils). Aneurysms were surgically created with abdominal fascia. Three days later, we percutaneously placed a self-expandable uncovered stent across the aneurysm. Coils were implanted through the stent into the aneurysm lumen. An aortogram immediately after stent placement showed no significant change in aneurysm lumen; however, in pigs that had aortograms between 6 weeks and 6 months after treatment, the diameter decreased (28% to 65%) in 4 of 5 pigs, and 1 had no discernible aneurysm. Three treated pigs died, but only 1 from rupture. In contrast, 7 untreated aneurysms ruptured (2 pigs died of other causes). Histological examination revealed that the aneurysm lumen was reduced after treatment by collagen production. This healing process was accelerated in aneurysms treated with both stents and coils. In contrast, only limited amounts of new collagen were found in untreated, ruptured aneurysms. Instead, the fascia was disrupted and there was evidence of collagen degradation. CONCLUSIONS: We found that uncovered stents reduce the likelihood of aneurysm rupture in a swine model without blocking arterial branches. The presence of coils enhanced filling of the lumen by collagen.