The choice of the graft conduit for coronary artery bypass grafting (CABG) has significant implications both in the short-and long-term. The patency of a coronary conduit is closely associated with an uneventful postoperative course, better long-term patient survival and superior freedom from re-intervention. The internal mammary artery is regarded as the primary conduit for CABG patients, given its association with long-term patency and survival. However, long saphenous vein (LSV) continues to be utilized universally as patients presenting for CABG often have multiple coronary territories requiring revascularization. Traditionally, the LSV has been harvested by creating incisions from the ankle up to the groin termed open vein harvesting (OVH). However, such harvesting methods are associated with incisional pain and leg wound infections. In addition, patients find such large incisions to be cosmetically unappealing. These concerns regarding wound morbidity and patient satisfaction led to the emergence of endoscopic vein harvesting (EVH). Published experience comparing OVH with EVH suggests decreased wound related complications, improved patient satisfaction, shorter hospital stay, and reduced postoperative pain at the harvest site following EVH. Despite these reported advantages concerns regarding risk of injury at the time of harvest with its potential detrimental effect on vein graft patency and clinical outcomes have prevented universal adoption of EVH. This review article provides a detailed insight into the technical aspects, outcomes, concerns, and controversies associated with EVH.
Objective To explore the advance in physical materials,chemical matrix, and biological seed cells for fabricating artificial nerve. Methods Recent literature relevant to artificial nerve, especially the achievement in physical material, chemical matrix and biological seed cells for fabricating artificial nerve, were extensively reviewed. Results Polymers of polylactic acid or polyglycolic acid and their polymer, polymer of hyaluronic acid and glut-aldehyde, polymer of polyacrylonitrile and polyvinylchloride were artificial nerve materials with the properties of good biocompatibility and biodegradation. A conduit with multichannel and high percentage of pores was beneficial to the regeneration of nerve. The activated Schwann cells were excellent seeds of artificial nerve. A suitable chemical matrix, such as laminin and alginate, could promote the regeneration of nerve. Conclusion The successful fabrication of artificial nerve lies in the advance in the mechanism of nerve regeneration and physical material, chemical matrix and biological seed cells.
ObjectiveTo evaluate the clinical outcome of valved homograft conduits (VHC) used for right ventricular outflow tract (RVOT) reconstruction in Fuwai Hospital in recent 13 years, and explore the factors influencing the long-term durability of VHC. MethodsClinical data of patients using VHC for RVOT reconstruction in Fuwai Hospital from November 2007 to October 2020 were retrospectively analyzed. The Kaplan-Meier survival curve was used to evaluate survival, VHC reintervention and VHC dysfunction. Cox proportional risk regression model was used to analyze the risk factors for VHC dysfunction. ResultsFinally 251 patients were enrolled, including 145 males and 106 females. The median age at surgery was 6.0 (0.3-67.0) years. Early death occurred in 5 (2.0%) patients. The follow-up was available for 239 (95.2%) patients, with the follow-up time of 0.3-160.0 (61.3±45.4) months. Five patients died during the follow-up, and the 1-year, 6-year, and 13-year survival rates were 96.6%, 95.5% and 95.5%, respectively. Eight patients received VHC reintervention during the follow-up, and freedom rates from VHC reintervention were 100.0%, 97.1% and 82.4% at 1 year, 6 years and 13 years, respectively. A total of 226 patients were followed up by echocardiography after discharge, with the follow-up time of 0.2-138.0 (48.5±40.5) months. During the follow-up, 46 (20.4%) patients developed VHC dysfunction, and freedom rates from VHC dysfunction at 1 year, 5 years, and 10 years were 92.6%, 79.6% and 59.3%, respectively. Univariate Cox regression analysis showed that age<6 years and VHC diameter<19 mm were risk factors for VHC dysfunction (P=0.029, 0.026), but multivariate regression analysis only indicated that age<6 years was an independent risk factor for VHC dysfunction (P=0.034). ConclusionThe early and late outcomes of VHC used for RVOT reconstruction are satisfactory, and the long-term durability of VHC is also optimal. In addition, age<6 years is an independent risk factor for VHC dysfunction.
Objective To summary the experience of extracardiac conduit total cavopulmonary connection (TCPC) and study the operative indication, design, method, and therapeutic efficacy. Methods 29 patients of extracardiac conduit TCPC were reviewed:the average age was 10 years. Of them, there were 9 cases of tricuspid atresia, 9 double inlet ventricle with left ventricular type, 3 mitral atresia, 3 corrected transposition of the great arteries with anatomically right ventricular hypoplasia and 5 double outlet of right ventricle with left ventricular hypoplasia. All patients underwent cardiopulmonary bypass, 12 cases with heart arrested, and 17 without heart arrested. In them, 20 cases’ superior vena cava were anastomosed directly to the upper margin of right pulmonary artery, 9 cases deviated to the left side of right pulmonary artery to enlarge the stoma. For the inferior vena cava stoma, 22 cases’ anterior walls of right atrium were partially incised, and sutured to the posterior wall, then anastomosed with Gore-Tex blood vessel prostheses and connected to pulmonary trunk, and the other 7 cases’ bottom of right atrium was totally incised, the proximal was closed, and the distal was anastomosised with Gore-Tex blood vessel prostheses and connected to the lower margin of right pulmonary artery, deviated to the right sidedness. Results 5 died in the first 22 cases, and the next 7 cases all survive. All patients were followed up for 3 months to 10 years with no late death. Of them, 12 cases had low cardiac output syndrome, and 11 cases of chylothorax. Conclusions Compared with other types of Fontan operation, the extracardiac conduit TCPC has better long-term effects in older or grown-up children. Nevertheless, strict operative adoption, reasonable operative design, refined procedures, carefully observation and treatment are the key points of improving therapeutic efficacy.
Objective To study the result of using nerve conduit coated with chitin and filled with a guide-fiber to repair peripheral nerve defect. Methods Twenty-four female adult SD rats were made the model of 14 mm-gap on bilateral sciatic nerve under sterile condition. The rats were randomly divided into 4 groups(n=6),group A: polymer polyglycolic-lactic acid(PGLA) nerve conduit coated with chitin and filled with a guide-fiber as experimental group to repair 14 mm gap of rat sciatic nerve；group B: PGLA nerve conduit coated with chitin； group C: PGLA nerve conduit； group D: autograft (control group). The repair result was evaluated by normal observation, EMG testing and S-100 histological immunostaining analysis 4 and 12 weeks after operation.Results Four weeks after the operation，there were new regenerated immature fibers in groups A,B and C, 12 weeks after the operation, the regenerated nerve fibers were seen to have bridged the gap. There were myelinated fibers equably distributed and rarely newgenerated nerve fibers in distal parts of group D. The repair result of PGLA nerve conduit coated with a chitin and filled with guide-fiber was better than that of groups B and C（Plt;0.05）. There was significant difference of nerve fiber diameter，thickness of myelin sheath and fiber density in group D from those in groups A, B and C（Plt;0.05），but there were degenerative changes such as vacuoles insheaths and myelin separation in proximal and few new regenerated nerve fibers in distal parts of group D. Conclusion PGLA nerve conduit coated with chitin and filled with a guide-fiber offers a possible substitute for the repair of peripheral nerve defect.
ObjectiveTo summarize the research progress of autologous vein nerve conduit for the repair of peripheral nerve defect.
MethodsThe recent domestic and foreign literature concerning autologous vein nerve conduit for repair of peripheral nerve defect was analyzed and summarized.
ResultsA large number of basic researches and clinical applications show that the effect of autologous venous nerve conduit is close to that of autologous nerve transplantation in repairing short nerve defect, especially the compound nerve conduit has a variety of autologous nerve tissue, cells, and growth factors, etc.
ConclusionAutologous vein nerve conduit for repair of non-nerve defect can be a good supplement of autologous nerve graft, improvement of autologous venous catheter to repair peripheral nerve defect is the research direction in the future.
OBJECTIVE To investigate the methods to fabricate repair materials of tissue engineered peripheral nerve with bioactivity of Schwann cells (SC). METHODS 1. The materials were made by dry-wet spinning process to fabricate PLA hollow fiber canal with external diameter of 2.3 mm, internal diameter of 1.9 mm, thickness of 0.4 mm, pore size of 20 to 40 microns, pore ratio of 70% and non-spinning fiber net with pore size of 100 to 200 microns, pore ratio of 85%. 2. SC were implanted into excellular matrix (ECM) gel to observe the growth of SC. 3. SC/ECM complex were implanted into non-spinning PLA fiber net to observe the growth of SC. 4. SC, SC/ECM and SC/ECM/PLA were implanted into PLA hollow fiber canal to bridge 10 mm defect of rat sciatic nerve. RESULTS 1. SC were recovered bipolar shape at 1 day after implantation, and could be survived 14 days in ECM gel. 2. After SC/ECM complex was implanted into PLA net, most of SC were retained in the pore of PLA net with the formation of ECM gel. SC could be adhered and grown on PLA fiber. 3. Most of SC in ECM gel could be survived to 21 days after transplantation. Survival cell numbers of SC/ECM and SC/ECM/PLA groups were obviously higher than SC suspension group. CONCLUSION Non-spinning PLA porous biodegradable materials with ECM is benefit for SC to be adhered and grown.
Objective To investigate the effects of chitosan/polyvinyl alcohol (PVA) nerve conduits for repairing radial nerve defect in Macaques. Methods Twelve adult Macaques weighing 3.26-5.35 kg were made the models of radial nerve defect (2 cm in length) and were randomly divided into 3 groups according to nerve grafting, with 4 Macaques in each group. Chitosan/PVA nerve conduit, non-graft, and autografts were implanted in the defects in groups A, B, and C, respectively. And the right radial nerves were used as normal control. At 8 months postoperatively, the general observation,electrophysiological methods, and histological examination were performed. Results At 8 months postoperatively, theregenerated nerve bridged the radial nerve defect in group A, but no obvious adhesion was observed between the tube and the peripheral tissue. The regenerated nerve had not bridged the sciatic nerve defect in group B. The adhesions between the implanted nerve and the peri pheral tissue were significant in group C. Compound muscle action potentials (CMAP) were detected in group A and group C, and no CMAP in group B. Peak ampl itude showed a significantly higher value in normal control than in groups A and C (P lt; 0.05), but there was no significant difference between groups A and C (P gt; 0.05). Nerve conduction velocity and latency were better in normal control than in groups A and C, and in group C than in group A, all showing significant differences (Plt; 0.05). The density of myl inated fibers in groups A and C was significantly lower than that in normal control (P lt; 0.05), but there was no significant difference between groups A and C (P gt; 0.05). The diameter and the myel in sheath thickness of the myl inated fibers in normal control were significantly higher than those in groups A and C, and in group C than in group A, all showing significant differences (P lt; 0.05). Conclusion The chitosan/PVA nerve conduits can promote the peripheral nerve regeneration, and may promise alternative to nerve autograft for repairing peripheral nerve defects.
Objective To explore a green route for the fabrication of thermo-sensitive chitosan nerve conduits, improve the mechanical properties and decrease the degradation rate of the chitosan nerve conduits. Methods Taking advantage of the ionic specific effect of the thermo-sensitive chitosan, the strengthened chitosan nerve conduits were obtained by immersing the gel-casted conduits in salt solution for ion-induced phase transition, and rinsing, lyophilization, and 60Co sterilization afterwards. The nerve conduits after immersing in NaCl solutions for 0, 4, 12, 24, 36, 48, and 72 hours were obtained and characterized the general observation, diameters and mechanical properties. According to the above results, the optimal sample was chosen and characterized the microstructure, degradation properties, and cytocompatibility. The left sciatic nerve defect 15 mm in length was made in 20 male Sprague Dawley rats. The autologous nerves (control group, n=10) and the nerve conduits (experimental group, n=10) were used to repair the defects. At 8 weeks after operation, the compound muscle action potential (CMAP) was measured. The regenerated nerves were investigated by gross observation and toluidine blue staining. The gastrocnemius muscle was observed by HE staining. Results With the increased ionic phase transition time, the color of the conduit was gradually deepened and the diameter was gradually decreased, which showed no difference during 12 hours. The tensile strength of the nerve conduit was increased gradually. The ultimate tensile strength showed significant difference between the 48 hours and 12, 24, and 36 hours groups (P<0.05), and no significant difference between the 48 hours and 72 hours groups (P>0.05). As a result, the nerve conduit after ion-induced phase transition for 48 hours was chosen for further study. The scanning electron microscope (SEM) images showed that the nerve conduit had a uniform porous structure. The degradation rate of the the nerve conduit after ion-induced phase transition for 48 hours was significantly decreased as compared with that of the conduit without ion-induced phase transition. The nerve conduit could support the attachment and proliferation of rat Schwann cells on the inner surface. The animal experiments showed that at 8 weeks after operation, the CMAPs of the experimental and control groups were (3.5±0.9) and (4.3±1.1) m/V, respectively, which showed no significant difference between the two groups (P<0.05), and were significantly lower than that of the contralateral site ［(45.6±5.6 m/V), P>0.05］. The nerve conduit of the experimental group could repair the nerve defect. There was no significant difference between the experimental and control groups in terms of the histomorphology of the regenerated nerve fibers and the gastrocnemius muscle. Conclusion The green route for the fabrication of thermo-sensitive chitosan nerve conduits is free of any toxic reagents, and has simple steps, which is beneficial to the industrial transformation of the chitosan nerve conduit products. The prepared chitosan nerve conduit can be applied to rat peripheral nerve defect repair and nerve tissue engineering.
ObjectiveTo summerize the early results of total cavopulmonary connection (TCPC) procedure with an extracardiac conduit in adults with congenital heart disease, and assess risk factors for postoperative delayed recovery in ICU.
MethodsWe retrospectively analyzed the clinical data of 20 adult patients underwent TCPC operation with extracardiac conduit in Fu Wai Hospital between January 2012 and December 2014. There were 14 female and 6 male patients at age of 16 to 33 (20.45±4.33) years.
ResultsThere was no hospital mortality. The time of ICU stay was 4.4±1.7 days. And time of hospital stay was 32.5±21.6 days. Morbidities included prolonged pleural effusion lasting more than 7 days in 12 patients (60.0%), new arrhythmias in 3 patients (15.0%), reexploration for bleeding in 3 patients (15.0%), surgical wound poor healing in 1 patient (5.0%). Dopamine and calcium were used in all the patients in the ICU, epinephrine in 18 patients, milrinone in 11 patients. Risk factors for postoperative delayed recovery in ICU were preoperative arrhythmias (P=0.02), cardiopulmonary bypass time longer than 120 min (P=0.04), plasma applications more than 2 000 ml (P=0.01), absence of fenestration (P=0.04), and pleural effusion lasting longer than 7 days (P=0.04).
ConclusionThe TCPC procedure with an extracardiac conduit can be performed in adults with encouraged early results. Actively vasoactive drugs to maintain circulation early in ICU has good results for the patient's recovery.
