Ebrahim Khabiri

Porcine carotid artery replacement with biodegradable electrospun poly-e-caprolactone vascular prosthesis

OBJECTIVE There is a continuous search for shelf-ready small-caliber vascular prostheses with satisfactory early and late results. Biodegradable scaffolds, repopulated by recipients cells regenerating a neovessel, can be a suitable option for adult and pediatric, urgent and elective cardiovascular procedures. METHODS This was a short-term experimental assessment of a new biodegradable vascular prosthesis for arterial replacement in the pig. Eleven pigs underwent bilateral carotid artery replacement with biodegradable electrospun poly-ε-caprolactone (PCL) nanofiber prostheses (internal diameter, 4 mm; length, 5 cm); or expanded polytetrafluoroethylene (ePTFE) prostheses as control. Perioperative anticoagulation was achieved with intravenous heparin (double baseline activated clotting time). Postoperatively, until conclusion of the study at 1 month, animals received aspirin and clopidogrel daily. Transit time flow was measured intraoperatively and at sacrifice. Doppler ultrasound (1 and 4 weeks) and a selective carotid angiography (4 weeks) were performed to assess patency. All explanted grafts were analyzed by histology, morphometry, and scanning electron microscopy in order to study graft-host interaction. RESULTS Surgical handling and hemostasis of the new prostheses were excellent. Patency rate was 78% (7/9) for PCL grafts, compared with 67% (4/6) for ePTFE grafts. Transit time flow and Doppler ultrasound showed no significant changes in flow and velocity or diameter over time in both groups. Both prostheses showed no detectable in vivo compliance as compared with native carotid artery. Percent neoendothelialization was 86% for PCL and 58% for ePTFE grafts (P = .008). Neointima formation was equal in both grafts. More adventitial infiltration of macrophages, myofibroblasts, and capillaries was seen in PCL grafts with a milder foreign-body reaction when compared with ePTFE implants. Both grafts showed similar endoluminal thrombus formation. CONCLUSIONS Biodegradable, electrospun PCL grafts showed good surgical and mechanical properties, no aneurysm formation, and similar short-term patency compared with ePTFE grafts. Rapid endothelialization and cell ingrowth confirms favorable PCL graft-recipient biological interaction. Despite good early results, long-term follow-up is required before clinical application.

Improved neo-endothelialization of small diameter ePTFE grafts with titanium coating

Background Patency of small synthetic bypass grafts is inferior compared to autologous grafts for revascularization procedures. Titanium coating of foreign surfaces has shown to decrease thrombogenicity, enhance biocompatibility and promote adhesion of endothelial cells. The aim of this study was to test the effect of titanium coating of small diameter ePTFE grafts on short term patency, neo-endothelialization and neointimal proliferation. Methods Bilateral carotid graft interposition was performed in 5 pigs with uncoated (n=5) and titanium-coated (n=5) ePTFE grafts (internal diameter=4 mm, length=5 cm), thus each pig served as its own control. At the end of the study (30 ± 3 days), patency and stenosis severity was assessed by carotid angiography. Animals were sacrificed and grafts were excised for histology and scanning electron microscopy. Morphometry of histologic sections was carried out to determine neointimal proliferation and percentage of neo-endothelial coverage. Results Patency rate was 80% for uncoated and titanium-coated grafts. Quantitative angiography did not show any significant difference in lumen size between two groups. Morphometry revealed a significantly higher cellular coverage with CD 31 positive endothelial cells for titanium-coated (84 ± 19%) than uncoated grafts (48 ± 26%, p<0.001). There was a non significant trend (p=0.112) towards increased neointimal proliferation in titanium-coated (94 ± 61 μm2/μm) compared to uncoated grafts (60 ± 57 μm2/μm). Conclusions Patency rate in uncoated and titanium-coated ePTFE grafts is similar at one month. However, titanium coated grafts show a significant improvement in neo-endothelialization compared to uncoated grafts.

Isolated Bilateral Profunda Femoris Artery Aneurysm

BACKGROUND Isolated bilateral profunda femoris artery aneurysm (PFAA) is a very rare entity. Most of the cases are unilateral and occur with synchronous aneurysms elsewhere. Symptoms range from none to limb ischemia or hemorrhage because of rupture. METHODS We present a rare case of PFAA. In contrast to the general rule, the patient had a bilateral PFAA which was isolated to the deep femoral artery. The aneurysm was discovered after signs of acute limb ischemia caused by distal embolization. The patient was treated surgically with open aneurysmectomy and ligation of a branch of the deep femoral artery. CONCLUSION PFAA are asymptomatic most of the time. Surgical repair is always recommended to prevent such life-threatening complications. Different treatment modalities are offered, including endovascular options. The presence of a PFAA should prompt screening for concomitant aneurysms.

Sequela-free long-term survival of a 65-year-old woman after 8 hours and 40 minutes of cardiac arrest from deep accidental hypothermia

In the setting of accidental deep hypothermia, rare cases of lengthy cardiac arrests may be associated with excellent long-term cardiovascular and neurologic outcomes. These unusual cases should be reported to a registry and studied further to advance our knowledge and improve treatments and outcomes for those affected by accidental deep hypothermia. We present here the longest, to our knowledge, cardiac arrest with an excellent long-term outcome.

Ascending aorto-superior mesenteric artery bypass as a surgical option for revascularization in mesenteric ischemia associated with type B aortic dissection

We report the case of an acute ischemia of the superior mesenteric artery (SMA) after endovascular fenestration of a complicated acute type B aortic dissection. An initial attempt for endovascular revascularization of the SMA failed, and an ascending aorto-superior mesenteric artery bypass was urgently performed to salvage the small bowel. Surgery of patients in these specific settings is more complex because an adequate, more distal inflow vessel is often not present due to the dissected aorta and iliac arteries. This surgical option could be lifesaving and should be part of the vascular surgeons armamentarium.

Successful palliation of acute superior vena caval obstruction after the Senning operation

Superior vena caval obstruction after an intraatrial baffle procedure can lead to acute cerebral complications and hence requires immediate management. We present a case of successful palliation of acute superior vena caval obstruction after a Senning procedure by establishing a venous shunt between the innominate vein and pulmonary artery. This technique resulted in immediate hemodynamic and functional improvement that subsequently allowed for the enlargement of the superior vena cava-right atrial junction with a pericardial patch.

Popliteal artery entrapment syndrome: report of two cases

Popliteal artery entrapment syndrome accounts for an important part of correctible causes of claudication and limb ischemia in young people. It is caused by an abnormal relation between the popliteal artery (PA) and the medial head of the gastrocnemius muscle. The diagnosis should be considered in any patient under 50 with calf claudication. The mainstay of treatment is prevention of PA fibrosis because if left untreated, the syndrome leads to irreversible damage to the PA with thrombosis and limb ischemia. We describe two cases of different types in 21- and 27-year-old males, respectively, and we review the literature about the presentation, diagnosis, classification and management of this entity.

Vascular ultrasound studies for the non-invasive assessment of vascular flow and patency in experimental surgery in the pig

Vascular ultrasound is a reliable non-invasive tool used for the routine assessment of vascular flow and patency in human recipients. We describe the use at three different time points (immediately, 1 week and 4 weeks postsurgery) of ultrasound studies and its validation by angiographic studies in 37 swine undergoing carotid graft replacement. We calculated predictive values (>92%), sensitivity (>85%) and specificity (>92%) with high results at all time points. Ultrasound appeared as an accessible non-invasive technique, providing rapid, safe, repeatable and reliable results. It is an excellent alternative to angiography, avoiding risks inherent to invasive methods and therefore contributing to animal welfare.

A novel high vacuum chest drainage system - a pilot study.

Aim To assess the safety and feasibility of use of a novel high vacuum chest drainage system (HVCDS) and its influence on the cardiovascular system compared to a conventional system (CCDS). Material and methods Five anesthetized pigs underwent a median sternotomy. Three drains were placed in retrocardiac, retrosternal and left pleural positions. The animals received a HVCDS (22 Fr with 180 2-mm holes, n = 2) or a CCDS (n = 2). In the fifth animal off pump coronary artery bypass graft (OPCABG) stabilizers were tested. After chest closure animals had three 30 min runs of artificial bleeding (5 ml/min) under different negative aspiration pressures (–2, –20, –40 kPa) for both groups, followed by standardized surgical bleeding (–40 kPa – HVCDS, – 2 kPa – CCDS). Hemodynamic parameters and each drains output were registered every 5 minutes and the residual blood was assessed. All catheters, the heart and left lung underwent macroscopic and histopathological examination. Results The application of the different pressures showed neither hemodynamic changes nor differences in blood drainage with both systems in two bleeding models. The HVCDS enabled drainage comparable to the CCDS but showed relevant clotting. Application of –20 kPa and –40 kPa caused macroscopic epicardial and pulmonary lesions in all tested devices including OPCABG stabilizers consisting of sub-epicardial or sub-pleural hemorrhage without myocyte or alveolar damage. Conclusions The novel and conventional chest drainage systems used at pressures up to 40 kPa induced no hemodynamic instability. Both systems showed adequate equal drainage, despite major HVCDS clotting. High negative pressure drainage with both systems showed focal sub-epicardial and subpleural hemorrhage. Thus, long-term assessment of high pressure drainage and potential interaction with fragile structures (coronary bypass graft) should be carried out.

Hospital Treatment of Hypothermia Victims in Cardiorespiratory Arrest

Hypothermia by submersion is associated with various levels of asphyxia and is often seen in accidental hypothermia [1]. Avalanche victims also suffer from asphyxia and show several other similarities with drowning. Therefore, we believe that the reported clinical and laboratory data, well documented in avalanche victims, can be applied to drowning victims [2, 3].