Postoperative Pericardial Adhesions Research Articles

A Case Report of Video-assisted Thoracoscopic Pericardiectomy for Postpericardiotomy Recurrent Loculated Pericardial Effusion

Abstract Surgical drainage, particularly pericardiotomy, which has a low recurrence rate, can safely and efficiently treat symptomatic pericardial effusion in patients with cancer. A thoracoscopic video-assisted pericardiectomy is an effective treatment option for rare instances of recurrent localized pericardial effusion. A 63-year-old male presented with a rare form of recurrent pericardial effusion that was initially circumferential, but recurred in a loculated form. On the right side, a loculated pericardial effusion caused right ventricular dysfunction and lower leg edema. The patient’s clinical symptoms, especially severe pedal edema, improved significantly after video-assisted thoracoscopic surgery with pericardiectomy through the right chest wall. Infrequent instances of recurrent loculated pericardial effusion after pericardiotomy may manifest with atypical symptoms. In addition to echocardiography, chest computed tomography can be used to examine in great detail local lesions caused by postoperative pericardial adhesions or scarring. Video-assisted thoracic surgery improves visualization and effectively treats loculated pericardial effusion during pericardiectomy.

DETERMINING THE TRANSLATIONAL POTENTIAL OF HUMAN PERICARDIAL FLUID TO IMPROVE CLINICAL OUTCOMES IN CARDIAC SURGERY

The pericardial space, which contains pericardial fluid (PF), maintains homeostatic conditions that facilitates optimal heart function. The loss of PF during surgery perturbs the equilibrium of this environment, contributing to postsurgical complications, including postoperative pericardial adhesion formation (PPAF) and postoperative atrial fibrillation (POAF), both of which involve immune-mediated pathways. We have yet to fully understand the exact pathophysiology of these adverse events. This study aimed to establish the immune profile of human PF, determine whether specific markers can drive inflammatory processes, such as fibrosis, and elucidate the underlying mechanisms that can result in such phenomena.

A review of animal models for post-operative pericardial adhesions.

Post-operative pericardial adhesions remain a serious complication after cardiac surgery that can lead to increased morbidity and mortality. Fibrous adhesions can destroy tissue planes leading to injury of surrounding vasculature, lengthening of operation time, and increased healthcare costs. While animal models are necessary for studying the formation and prevention of post-operative pericardial adhesions, a standardized animal model for inducing post-operative pericardial adhesions has not yet been established. In order to address this barrier to progress, an analysis of the literature on animal models for post-operative pericardial adhesions was performed. The animal model, method used to induce adhesions, and the time to allow development of adhesions were analyzed. Our analysis found that introduction of autologous blood into the pericardial cavity in addition to physical abrasion of the epicardium caused more severe adhesion formation in comparison to abrasion alone or abrasion with desiccation (vs. abrasion alone p = 0.0002; vs. abrasion and desiccation p = 0.0184). The most common time frame allowed for adhesion formation was 2 weeks, with the shortest time being 10 days and the longest being 12 months. Finally, we found that the difference in adhesion severity in all animal species was similar, suggesting the major determinants for the choice of model are animal size, animal cost, and the availability of research tools in the particular model. This survey of the literature provides a rational guide for researchers to select the appropriate adhesion induction modality, animal model, and time allowed for the development of adhesions.

Unique Angiogenesis From Cardiac Arterioles During Pericardial Adhesion Formation.

ObjectivesThe molecular mechanisms underlying post-operative pericardial adhesions remain poorly understood. We aimed to unveil the temporal molecular and cellular mechanisms underlying tissue dynamics during adhesion formation, including inflammation, angiogenesis, and fibrosis.Methods and ResultsWe visualized cell-based tissue dynamics during pericardial adhesion using histological evaluations. To determine the molecular mechanism, RNA-seq was performed. Chemical inhibitors were administered to confirm the molecular mechanism underlying adhesion formation. A high degree of adhesion formation was observed during the stages in which collagen production was promoted. Histological analyses showed that arterioles excessively sprouted from pericardial tissues after the accumulation of neutrophils on the heart surface in mice as well as humans. The combination of RNA-seq and histological analyses revealed that hyperproliferative endothelial and smooth muscle cells with dedifferentiation appeared in cytokine-exposed sprouting vessels and adhesion tissue but not in quiescent vessels in the heart. SMAD2/3 and ERK activation was observed in sprouting vessels. The simultaneous abrogation of PI3K/ERK or TGF-β/MMP9 signaling significantly decreased angiogenic sprouting, followed by inhibition of adhesion formation. Depleting MMP9-positive neutrophils shortened mice survival and decreased angiogenic sprouting and fibrosis in the adhesion. Our data suggest that TGF-β/matrix metalloproteinase-dependent tissue remodeling and PI3K/ERK signaling activation might contribute to unique angiogenesis with dedifferentiation of vascular smooth muscle cells from the contractile to the synthetic phenotype for fibrosis in the pericardial cavity.ConclusionsOur findings provide new insights in developing prevention strategies for pericardial adhesions by targeting the recruitment of vascular cells from heart tissues.

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

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. 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. 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. 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.

Surgical pericardial adhesions do not preclude minimally invasive epicardial pacemaker lead placement in an infant porcine model.

Pericardial adhesions in infants and small children following cardiac surgery can impede access to the epicardium. We previously described minimally invasive epicardial lead placement under direct visualization in an infant porcine model using a single subxiphoid incision. The objective of this study was to assess the acute feasibility of this approach in the presence of postoperative pericardial adhesions. Adhesion group piglets underwent left thoracotomy with pericardiotomy followed by a recovery period to develop pericardial adhesions. Control group piglets did not undergo surgery. Both groups underwent minimally invasive epicardial lead placement using a 2-channel access port (PeriPath) inserted through a 1 cm subxiphoid incision. Under direct thoracoscopic visualization, pericardial access was obtained with a 7-French sheath, and a pacing lead was affixed against the ventricular epicardium. Sensed R-wave amplitudes, lead impedances and capture thresholds were measured. Eight piglets underwent successful pericardiectomy and developed adhesions after a median recovery time of 45 days. Epicardial lead placement was successful in adhesion (9.5 ± 2.7 kg, n = 8) and control (5.6 ± 1.5 kg, n = 7) piglets. There were no acute complications. There were no significant differences in capture thresholds or sensing between groups. Procedure times in the adhesion group were longer than in controls, and while lead impedances were significantly higher in the adhesion group, all were within normal range. Pericardial adhesions do not preclude minimally invasive placement of epicardial leads in an infant porcine model. This minimally invasive approach could potentially be applied to pediatric patients with prior cardiac surgery.

Novel Trilaminar Polymeric Antiadhesion Membrane Prevents Postoperative Pericardial Adhesion

Postoperative pericardial adhesion formation is a prominent cause of morbidity and death in cardiovascular surgery, but there is still no ideal prevention method, especially in redo cases. This study investigated a novel antiadhesion trilaminar polymeric film compared with the Gore PRECLUDE Pericardial Membrane (W. L. Gore & Associates, Flagstaff, AZ) and a negative control. Our novel trilaminar membrane is composed of polyvinyl alcohol (PVA) and carboxymethylcellulose (CMC). An established pericardial adhesion rabbit model was used to test the property of the membrane. After sternotomy, a portion of pericardium was resected and the epicardium was abraded. Rabbits (n= 24) were randomly assigned to 3 groups: control group, no trilaminar membrane or expanded polytetrafluoroethylene (ePTFE); ePTFE group, or trilaminar membrane group (PVA-CMC group). Evaluation of adhesion formation was performed by resternotomy 4 weeks after the operation. The degree of tissue adhesion surrounding the heart in the PVA-CMC group was significantly less than in the control (P < .01) and ePTFE (P < .05) groups. The inflammation score in group PVA-CMC was significantly lower than that in the ePTFE (P < .01) and control (P < .01) groups. The fibrosis score was significantly lower in group PVA-CMC than that in the ePTFE (P < .05) and control (P < .01) groups. The novel trilaminar membrane effectively reduced postoperative pericardial adhesions. The placement of the trilaminar membrane at the time of sternal closure provides a novel combination to minimize the extent and severity of pericardial adhesions while providing a physical barrier between the sternum and the cardiac structures.

Use of a supramolecular polymeric hydrogel as an effective post-operative pericardial adhesion barrier.

Post-operative adhesions form as a result of normal wound healing processes following any type of surgery. In cardiac surgery, pericardial adhesions are particularly problematic during reoperations, as surgeons must release the adhesions from the surface of the heart before the intended procedure can begin, thereby substantially lengthening operation times and introducing risks of haemorrhage and injury to the heart and lungs during sternal re-entry and cardiac dissection. Here we show that a dynamically crosslinked supramolecular polymer-nanoparticle hydrogel, with viscoelastic and flow properties that enable spraying onto tissue as well as robust tissue adherence and local retention in vivo for two weeks, reduces the formation of pericardial adhesions. In a rat model of severe pericardial adhesions, the hydrogel markedly reduced the severity of the adhesions, whereas commercial adhesion barriers (including Seprafilm and Interceed) did not. The hydrogels also reduced the severity of cardiac adhesions (relative to untreated animals) in a clinically relevant cardiopulmonary-bypass model in sheep. This viscoelastic supramolecular polymeric hydrogel represents a promising clinical solution for the prevention of post-operative pericardial adhesions.

Decrease in VEGF-Induced Pericardial Adhesion Formation Using Bevacizumab After Surgery.

Some degrees of postoperative cardiac adhesions occur in response to the first cardiac surgery in patients that may limit surgeons for subsequent operations and increase the risk of heart injury. In this article, we established a model of postoperative pericardial adhesions, and because vascular endothelial growth factor (VEGF) seems to initiate adhesion formation through inflammatory responses, we used an anti-VEGF antibody, that is, bevacizumab, to examine its effects on postoperative adhesion formation. Twenty Wistar rats were divided in 2 groups: control and bevacizumab. After chest opening, pericardial sac was opened and the heart was fully exposed. In the bevacizumab group, bevacizumab (2.5 mg/kg) was applied locally on the heart and then the chest was closed. The control group received saline solution as placebo. After 42 days, high-sensitivity C-reactive protein in peripheral blood was measured, and re-sternotomy was performed to measure severity of pericardial adhesions. Then, the hearts were collected from all rats to evaluate percentage of CD-31-positive cells (as a marker of angiogenesis) using immunohistochemical staining. When the bevacizumab group was compared with the control group, we found that the mean score of adhesion (0.89 ± 0.38 vs 2.56 ± 0.41) and CD-31 expression (27.45 ± 3.75% vs 56.26 ± 1.98%) was decreased significantly after bevacizumab administration. However, we did not find any difference in high-sensitivity C-reactive protein levels of control and bevacizumab animals. In the current study, bevacizumab administration could effectively reduce adhesion formation after first sternotomy by preventing VEGF-induced angiogenesis through CD-31 downregulation.

Effects of Alcohol on Postoperative Adhesion Formation in Ischemic Myocardium and Pericardium

Postoperative formation of adhesions increases risk of complications during cardiac reoperations. We previously demonstrated that swine supplemented with vodka had a significant reduction in adhesions at sternotomy after previous thoracotomy. This follow-up study was conducted to determine reproducibility and the mechanism for adhesion reduction in swine supplemented with ethanol. An ameroid constrictor was placed in the left circumflex in 14 male Yorkshire swine to induce chronic myocardial ischemia through left minithoracotomy. Animals were supplemented postoperatively with ethanol (45 g ETOH, n= 7) or sucrose (80 g SUC, n= 7) for 7 weeks, followed by a reoperative median sternotomy. The ETOH group had significantly fewer adhesions, thinner pericardial thickness, decreased intramyocardial fibrosis, and decreased myocardial collagen deposition compared with the SUC group. In the myocardium, ETOH animals had decreased expression of proadhesion proteins focal adhesion kinase, paxillin, integrin-β1, transforming growth factor-β1 and phosphorylated SMAD and increased expression of adhesion breakdown proteins matrix metalloproteinase (MMP) 1, MMP2, MMP3, and MMP9 compared with SUC animals. However in the pericardium, ETOH animals had increased expression of proadhesion proteins focal adhesion kinase, paxillin, phosphorylated paxillin, vinculin, integrin-β1, tumor necrosis factor-α, transforming growth factor-β, and phosphorylated SMAD3, and decreased expression of adhesion breakdown proteins MMP1, MMP3, MMP9, and plasmin compared with SUC animals. Alcohol supplementation substantially reduced postoperative pericardial adhesion formation, attenuated pericardial thickening, and reduced myocardial fibrosis in response to chronic ischemia. Alcohol supplementation modulates adhesion protein and MMP/tissue inhibitor of metalloproteinase expression, favoring a profile associated with reduced pericardial adhesions. These results suggest that the myocardium is the driving factor in reducing pericardial adhesions and mediating the postoperative healing process.

A novel bioabsorbable pericardial membrane substitute to reduce postoperative pericardial adhesions in a rabbit model.

In paediatric cardiac surgery, reoperations remain challenging since the injury and the formation of dense adhesions before reoperations can be life-threatening to the heart, bypass conduits or great vessels. To prevent the formation of dense adhesions, a variety of different types of pericardial membrane substitute have been employed. However, due to peel formation, calcification and infection, the routine application of these pericardial membrane substitute has not been achieved clinically. A novel bioabsorbable membrane has been developed from polylactic acid (PLA) to overcome these drawbacks. The purpose of this study was to assess the biosafety and the effectiveness of PLA membrane as a new bioabsorbable pericardial membrane substitute after pericardium replacement in a rabbit model. A total of 33 rabbits underwent abrasion on the surface of the heart through right thoracotomy and were divided into a PLA membrane group (n = 17) and a control group (n = 16). Biosafety was assessed by comparing pre- and postoperative liver/kidney function and C-reactive protein levels. Subsequently, at 4 and 12 weeks postoperatively, the degree of reabsorption of the membrane and the intensity of adhesions were macroscopically assessed, followed by a microscopic evaluation for histological changes. Samples of the regenerated fibrous membranes that were harvested 12 weeks after implantation were used to perform immunostaining for cytokeratin and human bone marrow endothelial cell-1 (HBME-1). The PLA membrane group exhibited a little inflammatory response (P > 0.05) and liver/kidney dysfunction (P > 0.05). The PLA membrane was mostly absorbed by 12 weeks with the replacement of loosely adherent tissue. Moderate adhesions were found between the pericardial membrane substitute and the epicardium at the 4-week postoperative inspection. After 12 weeks postoperatively, the adhesions were found to have resolved completely. The composite score, which combined the histological findings of inflammation and the tightness of adhesions, was graded on a scale of 0 to 3. Significant differences between the PLA and control groups were detected at 4 weeks (1.2 ± 0.4, 2.1 ± 0.6; P = 0.007, respectively) and 12 weeks (0.5 ± 0.5, 2.5 ± 0.7; P = 0.001, respectively). Twelve weeks after the replacement of the pericardium with the PLA membrane, as shown by the cells positively immunostained for cytokeratin and HBME-1, the regenerated membrane consisted of a bilayer structure mimicking the native pericardium. To prevent the formation of adhesions after cardiac surgery, the bioabsorbable PLA membrane might serve as a promising substitute for the pericardium, which proved to be safe and efficacious in our study.

Alcohol and the Heart: A Proteomics Analysis of Pericardium and Myocardium in a Swine Model of Myocardial Ischemia

Previous studies have demonstrated that moderate alcohol consumption is cardioprotective and reduces postoperative pericardial adhesions; however, the mechanism is not fully understood. Using proteomic analysis, we sought to objectively investigate the effects of daily moderate alcohol consumption in the pericardium and myocardium in a swine model of chronic myocardial ischemia. Fourteen swine underwent placement of an ameroid constrictor to induce chronic myocardial ischemia. Animals were supplemented with 90 mL of ethanol daily (ETOH) or 80 g of sucrose of equal caloric value (SUC). After 7 weeks, the ischemic myocardium and pericardium were harvested for proteomics analysis. Pericardial proteomics analysis yielded 397 proteins, of which 23 were unique to SUC and 52 were unique to ETOH. Of the 322 common proteins, 71 were statistically significant and 23 were characterized (p < 0.05). Alcohol supplementation increased structural proteins, and decreased immune protease inhibitors and coagulation proteins in the pericardium (p < 0.01). Myocardial proteomics analysis yielded 576 proteins, of which 32 were unique to SUC and 21 were unique to ETOH. Of the 523 common proteins, 85 were significant, and 32 were characterized (p < 0.05). Alcohol supplementation decreased cardiac remodeling proteins, cell death proteins and motor proteins, and increased metabolic proteins (p < 0.05). The results suggest that daily moderate alcohol consumption affects numerous pathways that contribute to cardioprotection, including cardiac remodeling, metabolism, and cell death. Our findings reveal the biosignature of myocardial and pericardial protein expression in the setting of chronic myocardial ischemia and daily moderate alcohol consumption.

Assessment of the efficacy of Ankaferd blood stopper on the prevention of postoperative pericardial adhesions : cardiovascular topic

SummaryObjectivesAnkaferd has been used as a blood-stopping agent and it may also have an anti-inflammatory effect. We investigated the efficacy of Ankaferd in preventing postoperative pericardial adhesions in an experimental rabbit model.MethodsSixteen New Zealand white rabbits were used and categorised into two groups: an Ankaferd and a control group. The Ankaferd group of rabbits was treated with a sponge impregnated with Ankaferd solution, which was applied over the abraded epicardium. A sponge impregnated with 0.9% isotonic NaCl solution was applied to the control group using the same protocol. Scores for adhesion and visibility of coronary vessels were graded by macroscopic examination, and pericardial tissues were analysed microscopically in terms of inflammation and fibrosis.ResultsIn the Ankaferd group, the adhesion scores were significantly higher than in the control group (p = 0.007). When the groups were compared according to the prevalence of fibrosis and degree of inflammation, the Ankaferd group was found to be statistically significantly different from the control group in terms of prevalence of fibrosis (p = 0.028).ConclusionTopical application of Ankaferd to prevent postoperative pericardial adhesions increased adhesion and fibrosis scores.

Combined Application of Acellular Bovine Pericardium and Hyaluronic Acid in Prevention of Postoperative Pericardial Adhesion

An experiment was designed to find the suitable acellular bovine pericardium (ABP) patch in pericardial cavity reconstruction and to evaluate the effect of sodium hyaluronic acid (NaHA) on inflammatory reaction in prevention of pericardial adhesions. The pericardial adhesion model was established in 20 rabbits, weighing from 3.2 to 3.6 kg. Groups were classified as follows: Group A (n = 5), the control group, the pericardium was directly closed; Group B (n = 5), 0.15% glutaraldehyde-treated ABP (low cross-link degree); Group C, 0.3% glutaraldehyde-treated ABP (middle cross-link degree); Group D, 0.15% glutaraldehyde-treated ABP + NaHA solution. Blood samples were collected at 6 h, 24 h, 3 days, and 5 days, to assay postoperative inflammatory reaction. The tenacity and severity of adhesions were evaluated 2 months after operation, by macroscopic and microscopic examinations, and Q-PCR (real-time quantitative polymerase chain reaction) test was used to quantitatively analyze the associated genes with adhesion. Pericardium regeneration was demonstrated by immunohistochemical technique to identify mesothelial cells. In Group D, the serum concentration of tumor necrosis factor-α (TNF-α) was significantly lower in the early postoperative period, and the mean adhesion score (adhesion between the epicardium and ABP) was significantly lower compared with the control group (Groups D vs. A: 0.20 ± 0.45 vs. 2.00 ± 0.71, P = 0.009*). The signs of degradation of the ABPs were observed 2 months postoperation in Groups D and B. Immunohistochemically, the positive cytokeratin AE1 staining results demonstrated the relatively total regeneration of the pericardium in Group D. Signs of regeneration were observed in Group D. Compared with the control group, the level of TGF-β2 in Group D was significantly lower (0.00132 ± 0.00114, P = 0.022*). The TGF-β3 level was statistically significant, being highest in Group D (0.00805 ± 0.00136, P = 0.029*). The mean quantity of Smad6 in Group D was also lower than the other groups. Low cross-link degree ABP may be an efficient physical block between the epicardium and the sternum and also an ideal scaffold for pericardial tissue regeneration, whereas combined use with NaHA may significantly reduce postoperative pericardial adhesions. The signal transduction pathway of transforming growth factor-β (TGF-β) and Smad6 may play a key role in the formation of pericardial adhesion.

Epicardial mapping and ablation of arrhythmias: is magnetic navigation the answer we have been waiting for?

Epicardial mapping and ablation of arrhythmias: is magnetic navigation the answer we have been waiting for?

Alcohol reduces postoperative pericardial adhesion formation in swine

had microscopically positive margins (all radiation inductiontreated). Twenty-seven patients had complete response, 44 had partial response. Median number of lymph nodes resected was 17(1-39). Median length of stay: 12 days (1-77). There was one perioperative death (0.8%). Thirty-four patients had major complications: pulmonary 12, cardiac 3, bleeding 1, chylothorax 7, recurrent nerve injuries 7, leak 11 (3 necessitating intervention). No conduit necrosis or need for diversion was recorded. Median follow-up of 86 patients still alive: 20.5 months (3 monthse9.5 years). Five-year survival was 50%.

Effect of topical N-acetylcysteine in the prevention of postoperative pericardial adhesion formation in a rabbit model

N-acetylcysteine (NAC), a precursor of reduced glutathione, has been in clinical use primarily as a mucolytic. In addition, NAC is well known for their free radical scavenging and antioxidant properties. Increasing of reactive oxygen products occurring during cardiac surgery can play an important role in postoperative adhesion formation. We investigated to the efficacy of the NAC for postoperative pericardial adhesions. Sixteen New Zealand white rabbits (2.5-3 kg) were used and categorized into two groups including study (use of NAC) and control groups. In both groups, the pericardium was opened longitudinally, and the exposed epicardial surfaces were abraded with dry gauze. The rabbits were divided into two groups: Group 1 was treated with the sponge, which impregnated with NAC solution, (10%, 300 mg/3 ml) and applied over the abraded epicardium for 5 min (n=8). Group 2 was the control, and the sponge, which was impregnated with 3-ml isotonic NaCl solution (0.9%), was applied onto the surface of the abraded epicardium for 5 min (n=8). After a period of 2 weeks, the animals were sacrificed. The scores of adhesion were graded by macroscopic examination, and the pericardial tissues were analyzed microscopically in point of inflammation and fibrosis. In Group 1, the adhesion scores were significantly lower compared with the control group [Group 1 vs. 2; 1 (1-2) vs. 3 (2-3), P<.001]. No significant difference was found between the groups in terms of the severity of inflammation [Group 1 vs. 2; 1.5 (1-3) vs. 2.5 (1-3), P=.083]. There was a difference between groups in terms of the degree of fibrosis [Group 1 vs. 2; 2 (1-2) vs. 3 (2-3), P=.007]. The use of NAC for preventing postoperative pericardial adhesions was reduced to adhesion and fibrosis scores in an experimental rabbit model. There was no statistically significant difference between groups in terms of inflammatory scores. The NAC effectively prevented the formation of pericardial adhesion.

Prevention of Postoperative Pericardial Adhesions With TachoSil

The prevention of the pericardial adhesions largely accountable for the technical difficulty and risk of injury inherent to resternotomy continues to gain in importance with the increasing frequency of reoperations. The hemostatic sponge TachoSil (Nycomed Austria GmbH, Linz, Austria), has shown promising results in adhesion prevention in several regions of the body. This study was designed to evaluate its effectiveness in the prevention of pericardial adhesions in comparison with the Gore-Tex (W. L. Gore and Assoc, Flagstaff, AZ) surgical membrane and a control. Twenty-four rabbits were distributed into 3 groups: TachoSil, Gore-Tex, or no barrier agent (control). After median sternotomy and pericardiotomy, the cardial surface was exposed to the aggravating effects of room air, irrigation, and gauze abrasion for one hour. A pericardial defect was created and repaired with one of the barrier agents, or left uncovered (control). Resternotomy was performed after 6 months for the evaluation of adhesion formation. Significantly fewer macroscopic adhesions were observed with TachoSil than Gore-Tex in all regions (p < 0.05) excluding the coronary arteries, where the difference in favor of TachoSil did not achieve significance (0.05< p-value <0.10). TachoSil also demonstrated significantly fewer retrosternal adhesions than the control, as well as a universal non-significant trend of fewer adhesions in all regions. The limited lesions present in the TachoSil group were filmy in nature and removed with blunt dissection relatively easily. No significant differences were found between Gore-Tex and the control. Microscopically, the least pronounced fibrosis formation and inflammatory reaction was detected with TachoSil. TachoSil is effective in the prevention of pericardial adhesions.

The Effect of Mitomycin-C in Reducing Pericardial Adhesion After Cardiac Surgery in Rabbits

BackgroundMitomycin-C has been in clinical use primarily as a chemotherapeutic agent and is well known for antifibrotic properties. It has been widely used to prevent postoperative fibroblast proliferation and reduce scar adhesion in ophthalmologic and otolaryngologic operations. We investigated the efficacy of mitomycin-C in reducing postoperative pericardial adhesions in a rabbit model. MethodsNew Zealand white rabbits were used and categorized into 2 groups, study (use of mitomycin-C) and control. Group 1 (n = 8) was treated with a sponge impregnated with mitomycin-C solution that was applied over the abraded epicardium. In group 2 (control group), the sponge was impregnated with 0.9% isotonic NaCl solution and was applied with the same protocol as the mitomycin-C–impregnated sponge in group 1 (n = 8). Rabbits were humanely killed at a mean of 2 weeks. The scores of adhesion were graded by macroscopic examination, and the pericardial tissues were analyzed microscopically in terms of inflammation and fibrosis. ResultsIn group 1, the adhesion scores were significantly lower than the control group's. No significant difference was found between the groups in terms of the severity of inflammation. There was a difference between groups in terms of the degree of fibrosis. ConclusionsThe use of mitomycin-C to prevent postoperative pericardial adhesions reduced adhesion and fibrosis scores in an experimental rabbit model. However, efficacy in reducing inflammation was not demonstrated.

Effects of alcohol on pericardial adhesion formation in hypercholesterolemic swine

Reoperative cardiac surgery is complicated in part because of extensive adhesions encountered during the second operation. The purpose of this study was to examine the effects of alcohol with and without resveratrol (red wine vs vodka) on postoperative pericardial adhesion formation in a porcine model of hypercholesterolemia and chronic myocardial ischemia. Male Yorkshire swine were fed a high-cholesterol diet to simulate conditions of coronary artery disease followed by surgical placement of an ameroid constrictor to induce chronic ischemia. Postoperatively, control pigs continued their high-cholesterol diet alone, whereas the 2 experimental groups had diets supplemented with red wine or vodka. Seven weeks after ameroid placement, all animals underwent reoperative sternotomy. Compared with controls, pericardial adhesion grade was markedly reduced in the vodka group, whereas there was no difference in the wine group. Intramyocardial fibrosis was significantly reduced in the vodka group compared with controls. There was no difference in expression of proteins involved in focal adhesion formation between any groups (focal adhesion kinase, integrin alpha-5, integrin beta-1, paxillin, vinculin, protein tyrosine kinase 2, protein kinase C ε, and phosphorylated protein kinase C ε). The wine group exhibited elevated C-reactive protein levels versus the control and vodka groups. Postoperative vodka consumption markedly reduced the formation of pericardial adhesions and intramyocardial fibrosis, whereas red wine had no effect. Analysis of protein expression did not reveal any obvious explanation for this phenomenon, suggesting a post-translational effect of alcohol on fibrous tissue deposition. The difference in adhesion formation in the vodka versus wine groups may be due to increased inflammation in the wine group.