Robert A. Brenes

Current Usage and Future Directions for the Bovine Pericardial Patch

Bovine pericardium (BP) is widely used in surgery and is commonly used as a patch after arteriotomy in cardiovascular surgery. BP patches have several advantages compared with prosthetic patches, including superior biocompatability, easy handling, less suture line bleeding, and possibly reduced rates of infection. These advantages of BP have led to its common use during carotid endarterectomy (CEA). However, long-term clinical results reported after CEA have suggested several issues that may be related to the patch, including restenosis, pseudoaneurysm formation, infection, fibrosis, calcification, and thrombosis. These complications may diminish the long-term efficacy of CEA and suggest potential areas for improvement of surgical patches. Understanding the mechanisms by which BP heals after patch angioplasty may lead to next generation tissue-engineered patches.

Toward A Mouse Model of Hind Limb Ischemia to Test Therapeutic Angiogenesis

INTRODUCTION Several clinical trials are currently evaluating stem cell therapy for patients with critical limb ischemia that have no other surgical or endovascular options for revascularization. However, these trials are conducted with different protocols, including use of different stem cell populations and different injection protocols, providing little means to compare trials and guide therapy. Accordingly, we developed a murine model of severe ischemia to allow methodic testing of relevant clinical parameters. METHODS High femoral artery ligation and total excision of the superficial femoral artery was performed on C57BL/6 mice. Mononuclear cells (MNCs) were isolated from the bone marrow of donor mice, characterized using fluorescence-activated cell sorting, and injected (5×10(5) to 2×10(6)) into the semimembranosus (proximal) or gastrocnemius (distal) muscle. Vascular and functional outcomes were measured using invasive Doppler imaging, laser Doppler perfusion imaging, and the Tarlov and ischemia scores. Histologic analysis included quantification of muscle fiber area and number as well as capillary density. RESULTS Blood flow and functional outcomes were improved in MNC-treated mice compared with controls over 28 days (flow: P<.0001; Tarlov: P=.0004; ischemia score: P=.0002). MNC-treated mice also showed greater gastrocnemius fiber area (P=.0053) and increased capillary density (P=.0004). Dose-response analysis showed increased angiogenesis and gastrocnemius fiber area but no changes in macroscopic vascular flow or functional scores. Overall functional outcomes in mice injected proximally to the ischemic area were similar to mice injected more distally, but muscle flow, capillary density, and gastrocnemius fiber area were increased (P<.05). CONCLUSIONS High femoral ligation with complete excision of the superficial femoral artery is a reliable model of severe hind limb ischemia in C57BL/6 mice that shows a response to MNC treatment for functional and vascular outcomes. A dose response to the injection of MNCs appears to be present, at least microscopically, suggesting that an optimal cell number for stem cell therapy exists and that preclinical testing needs to be performed to optimally guide human trials. Injection of MNCs proximal to the site of ischemia may provide different outcomes compared with distal injection and warrants additional study.

Stem cell therapy for critical limb ischemia: What can we learn from cell therapy for chronic wounds?

Although much progress has been made regarding our knowledge of stem cells and their potential applications for therapeutic angiogenesis, there has been less success with the clinical application of this knowledge to patients with critical limb ischemia (CLI). Patients with CLI often have chronic wounds and newer cell-based therapies for chronic wounds show interesting parallels to stem cell therapy for CLI. Several human-derived wound care products and therapies, including human neonatal fibroblast-derived dermis (Dermagraft®), bilayered bioengineered skin substitute (Apligraf®), recombinant human platelet-derived growth factor and autologous platelet-rich plasma may provide insight into the mechanisms through which differentiated cells can be used as therapy for chronic wounds, and, analogously, by which stem cells might function therapeutically in CLI.

Cell-based interventions for therapeutic angiogenesis: review of potential cell sources

Alternative therapies are currently being developed to treat patients with chronic limb ischemia who are unable to be revascularized in order to avoid amputation. Cell-based therapy using mononuclear cells is gaining attention as many clinical trials are currently underway. We review cell differentiation along with the different potential cell sources for use in therapeutic angiogenesis.

Video assisted thoracoscopic resection of a posterior mediastinal Castleman's tumor

Castlemans disease (CD) or angiofollicular lymph node hyperplasia is a rare spectrum of lymphoproliferative disorders. CD tumors are commonly localized in the mediastinum and are usually asymptomatic. The mainstay of treatment is surgical resection and has typically been performed using open thoracotomy. Few reports in the literature describe video assisted thoracoscopic resection of these tumors. The differential diagnosis for mediastinal masses is extensive, and CD tumors, although uncommon, should be considered. We describe a case report of a posterior mediastinal Castlemans tumor adherent to the esophagus, which was resected thoracoscopically and review the literature.

Prevention of type II endoleak by laparoscopic inferior mesenteric artery ligation.

Abdominal aortic aneurysm repair by endovascular techniques have gained wide acceptance as a treatment option. A potential well-known complication of endovascular repair includes endoleak. Specifically, type II endoleak, which is described as retrograde flow into the aneurysm sac through collateral vessels, can occur in up to 30% of patients. Certain preoperative factors can predict which patients may develop type II endoleak. This article describes laparoscopic inferior mesenteric artery ligation prior to endovascular abdominal aortic aneurysm repair as a viable treatment option in the prevention of type II endoleak.

Hyaluronate-Iodine Complex: A New Adjunct for the Management of Complex Sternal Wounds After a Cardiac Operation

A wound-healing agent developed in the European Union is based on the combination of organic hyaluronan with inorganic iodine. The aim of this pilot study was to assess the efficacy and safety of hyaluronate-iodine in the treatment of sternal wounds. Eight patients with sternal wound dehiscence were entered into the study. After debridement, wounds were dressed with gauze soaked in hyaluronate-iodine. In one patient with an epipleural abscess, hyaluronate-iodine was instilled directly into the abscess cavity daily. Complete healing was achieved in 7 patients, and 1 patient underwent a reconstructive operation for wound closure. The mean (SD) length of treatment was 136 (114.2) days. No adverse effects or complications were apparent in this group. Hyaluronate-iodine is safe and effective in healing sternal wound dehiscence. Randomized controlled trials are needed for further validation.

Blind loop: rare but important surgical complication

BackgroundSurgical complications worldwide are dreaded by both patients and physicians alike. They represent significant and serious morbidity and mortality, and contribute substantially to increased costs of healthcare.Case presentationOur Case Report describes a 65yo Caucasian man with an extensive operative history for Crohn’s disease, including 4 laparotomies with small bowel resections to ameliorate small bowel obstructions. He presented with signs and symptoms of a chronic draining sinus, but was found to have a Blind Loop of bowel. This finding is believed to be the result of a surgical complication.ConclusionWhile the Case Reports discusses this particular patient presentation, the paper defines, describes and offers treatment strategies for Enterocutaneous Fistulas (ECF). We offer aim to add Blind Loop to the differential diagnosis when presented with a patient with signs and symptoms of ECF.

QS35. Cumulative Initial Experience Using Hyaluronate-Iodine Complex in Wound Healing

Fourteen patients (nineteen wounds) have been entered into our prospective study. Nine patients (twelve wounds) have completed treatment. Of the twelve wounds, eleven have gone on to complete healing with a mean healing time of 21 20.82 weeks. Treatment was discontinued in one patient due to burning/painful application of ointment after twenty-two weeks with 20.2% wound area remaining to heal. Five patients (seven wounds) are still undergoing treatment satisfactorily.