Adhesion barriers in cardiac surgery: A systematic review of efficacy.

BACKGROUND: Postoperative pericardial adhesions have been associated with increased morbidity, mortality, and surgical difficulty. Barriers exist to limit adhesion formation, yet little is known about their use in cardiac surgery. The study presented here provides the first major systematic review of adhesion barriers in cardiac surgery. METHODS: Scopus and PubMed were assessed on November 20, 2020. Inclusion criteria were clinical studies on human subjects, and exclusion criteria were studies not published in English and case reports. Risk of bias was evaluated with the Cochrane Risk of Bias Tool. Barrier efficacy data was assessed with Excel and GraphPad Prism 5. RESULTS: Twenty-five studies were identified with a total of 13 barriers and 2928 patients. Polytetrafluoroethylene (PTFE) was the most frequently evaluated barrier (13 studies, 67% of patients) with adhesion formation rate of 37.31% and standardized tenacity score of 26.50. Several barriers had improved efficacy. In particular, Cova CARD had a standardized tenacity score of 15.00. CONCLUSIONS: Overall, the data varied considerably in terms of study design and reporting bias. The amount of data was also limited for the non-PTFE studies. PTFE has historically been effective in preventing adhesions. More recent barriers may be superior, yet the current data is nonconfirmatory. No ideal adhesion barrier currently exists, and future barriers must focus on the requirements unique to operating in and around the heart.

Ovary-Sparing Surgery for Ovarian Teratoma in an Infant with Nonbilious Vomiting.

Ovarian teratoma is the most common ovarian tumor in children with an overall incidence of 2.6 cases per 100,000 girls per year. Diagnosis and management are challenging due to its nonspecific presentation, malignancy determination, and need to conserve fertility. A previously healthy 5-month-old female infant presented with fever, abdominal distension, and nonbilious emesis, and an 8.2 × 6.8 × 6.1-centimeter pelvic mass originating from the left adnexa was found on imaging. Due to concern for malignancy and torsion, exploratory laparotomy and ovarian-sparing surgery (OSS) with resection of the mass were performed. Histology showed a grade 1 teratoma. This case illustrates a challenging diagnosis and its symptom overlap with other etiologies in infants. The keys to diagnosing and managing this entity are including ovarian pathology in the differential diagnosis and performing OSS whenever possible. Furthermore, ultrasound follow-up is needed to monitor for ipsilateral and contralateral ovarian tumors later in life.

A Simplified Model for Heterotopic Heart Valve Transplantation in Rodents.

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of transplant with the potential to deliver durable heart valves capable of somatic growth with no requirement for anticoagulation. However, the immunobiology of heart valve transplants remains unexplored, highlighting the need for animal models to study this new type of transplant. Previous rat models for heterotopic aortic valve transplantation into the abdominal aorta have been described, though they are technically challenging and costly. For addressing this challenge, a renal subcapsular transplant model was developed in rodents as a practical and more straightforward method for studying heart valve transplant immunobiology. In this model, a single aortic valve leaflet is harvested and inserted into the renal subcapsular space. The kidney is easily accessible, and the transplanted tissue is securely contained in a subcapsular space that is well vascularized and can accommodate a variety of tissue sizes. Furthermore, because a single rat can provide three donor aortic leaflets and a single kidney can provide multiple sites for transplanted tissue, fewer rats are required for a given study. Here, the transplantation technique is described, providing a significant step forward in studying the transplant immunology of heart valve transplantation.

Devices to enhance organ perfusion during cardiopulmonary resuscitation.

INTRODUCTION: The recommended method of cardiopulmonary resuscitation (CPR) has been closed-chest cardiac compressions, but the development of CPR adjunctive devices has called into question the efficacy and role of these adjunctive devices. In this review, we provide a comprehensive evaluation and discussion on the commercially available noninvasive CPR adjuncts used during out-of-hospital cardiac arrest (OHCA). AREAS COVERED: We review the three most common CPR adjunctive devices: the piston mechanism, the load distributing band, and the impedance threshold device. All three CPR adjunctive devices have preclinical data to support their use during cardiac arrest. In clinical trials, limited data show improvement in survival and neurologic recovery for these devices, and there is insufficient high-level evidence to support their use over manual chest compressions. However, there is a role for them when adequate manual chest compressions are not feasible. EXPERT OPINION: The commercially available CPR adjuncts do not consistently show improved outcomes in the literature. There is still a need for research and development into innovative solutions to improve OHCA survival and neurologic recovery. Efforts focused on increasing the speed of CPR initiation and increasing perfusion to the cerebral and coronary vasculature have the potential to advance resuscitative practices.

Surgical techniques for aortic valve xenotransplantation.

BACKGROUND: Heart valve replacement in neonates and infants is one of the remaining unsolved problems in cardiac surgery because conventional valve prostheses do not grow with the children. Similarly, heart valve replacement in children and young adults with contraindications to anticoagulation remains an unsolved problem because mechanical valves are thrombogenic and bioprosthetic valves are prone to early degeneration. Therefore, there is an urgent clinical need for growing heart valve replacements that are durable without the need for anticoagulation. METHODS: A human cadaver model was used to develop surgical techniques for aortic valve xenotransplantation. RESULTS: Aortic valve xenotransplantation is technically feasible. Subcoronary implantation of the valve avoids the need for a root replacement. CONCLUSION: Aortic valve xenotransplantation is promising because the development of GTKO.hCD46.hTBM transgenic pigs has brought xenotransplantation within clinical reach.

Cellular Viability of Partial Heart Transplant Grafts in Cold Storage.

Congenital heart defects are the most common types of birth defects in humans. Children with congenital heart defects frequently require heart valve replacement with an implant. Unfortunately, conventional heart valve implants do not grow. Therefore, these children are committed to serial re-operations for successively larger implant exchanges. Partial heart transplantation is a new and innovative approach to deliver growing heart valve implants. However, the transplant biology of partial heart transplant grafts remains unexplored. This is a critical barrier for clinical translation. Therefore, we investigated the cellular viability of partial heart transplants in cold storage. Histology and immunohistochemistry revealed no morphological differences in heart valves after 6, 24, or 48 h of cold storage. Moreover, immunohistochemistry showed that the marker for apoptosis activated caspase 3 and the marker for cell division Ki67 remained unchanged after 48 h of cold storage. Finally, quantification of fluorescing resorufin showed no statistically significant decrease in cellular metabolic activity in heart valves after 48 h of cold storage. We conclude that partial heart transplants remain viable after 48 h of cold storage. These findings represent the first step toward translating partial heart transplantation from the bench to the bedside because they have direct clinical implications for the procurement logistics of this new type of transplant.

Intestinal crypt-derived enteroid coculture in presence of peristaltic longitudinal muscle myenteric plexus.

The role of enteric neurons in driving intestinal peristalsis has been known for over a century. However, in recent decades, scientists have begun to unravel additional complex interactions between this nerve plexus and other cell populations in the intestine. Investigations into these potential interactions are complicated by a paucity of tractable models of these cellular relationships. Here, we describe a novel technique for ex vivo coculture of enteroids, so called "mini-guts," in juxtaposition to the longitudinal muscle myenteric plexus (LMMP). Key to this system, we developed a LMMP culture media that: (i) allows the LMMP to maintain ex vivo peristalsis for 2 weeks along with proliferation of neurons, glia, smooth muscle and fibroblast cells, and (ii) supports the proliferation and differentiation of the intestinal stem cells into enteroids complete with epithelial enterocytes, Paneth cells, goblet cells, and enteroendocrine cells. Importantly, this technique identifies a culture condition that supports both the metabolic needs of intestinal epithelium as well as neuronal elements, demonstrating the feasibility of maintaining these two populations in a single culture system. This sets the stage for experiments to better define the regulatory interactions of these two important intestinal cell populations.

Immune Privilege of Heart Valves.

Immune privilege is an evolutionary adaptation that protects vital tissues with limited regenerative capacity from collateral damage by the immune response. Classical examples include the anterior chamber of the eye and the brain. More recently, the placenta, testes and articular cartilage were found to have similar immune privilege. What all of these tissues have in common is their vital function for evolutionary fitness and a limited regenerative capacity. Immune privilege is clinically relevant, because corneal transplantation and meniscal transplantation do not require immunosuppression. The heart valves also serve a vital function and have limited regenerative capacity after damage. Moreover, experimental and clinical evidence from heart valve transplantation suggests that the heart valves are spared from alloimmune injury. Here we review this evidence and propose the concept of heart valves as immune privileged sites. This concept has important clinical implications for heart valve transplantation.

Differential immune signatures in the tumor microenvironment are associated with colon cancer racial disparities.

BACKGROUND: Disparities in colon cancer (CC) outcomes may be due to a more aggressive phenotype in African American patients in the setting of a decreased tumor immunity, though the precise mechanism for this result has not been well elucidated. To explore the molecular factors underlying CC disparities, we compared the immunogenomic signatures of CC from African American and European American patients. METHODS: We identified all CC patients from the publicly available Cancer Genome Atlas for whom race and survival data are available. Immunophenotype signatures were established for African American and European American patients. Comparisons were made regarding survival and a multivariable linear regression model was created to determine the association of immune cellular components with race. Differential gene expression was also assessed. RESULTS: Of the 254 patients identified, 58 (23%) were African American and 196 (77%) were European American. African American patients had a decreased progression free survival (p = 0.04). Tumors from African American patients displayed a reduced fraction of macrophages and CD8+ T cells and an increased fraction of B cells compared with tumors from European Americans. Differences persisted when controlling for sex, age, and disease stage. Immunostimulatory and immunoinhibitory gene profiles including major histocompatibility complex expression differed by race. CONCLUSIONS: Differences in the tumor immune microenvironment of African American as compared to European American CC specimens may play a role in the survival differences between the groups. These differences may provide targeted therapeutic opportunities.