Mitral valve repair with artificial chordae replacement in children: a single-center experience.

OBJECTIVES: To summarize the experience of mitral valve (MV) repair with artificial chordae replacement in children, and analyze early and intermediate outcomes. METHODS: From January 2011 to May 2019, all patients (< 18 years) who received MV repair with artificial chordae replacement were retrospectively reviewed. Freedom from MV reoperation, MV dysfunction, moderate or severe MR were estimated by the Kaplan-Meier curve and log-rank test. RESULTS: A total of 30 patients were included in this study. According to our definition, 15 patients had simple lesions and 15 patients had complex lesions. During 36 months' follow-up (range 3-97 months), two patients received MV reoperation and seven patients developed MV dysfunction, including six patients with moderate or severe MR and one patient with mitral stenosis. Freedom from MV reoperation at 1, 5 and 8 years were 100%, 91.3% and 91.3%, respectively. And freedom from MV dysfunction at 1, 3 and 5 year were 96.0%, 77.1% and 61.8%, respectively. Five-year freedom from MV dysfunction showed significant differences between patients with simple lesions and patients with complex lesions (100% vs 32.7%, log-rank P = 0.008), and between patients aged less than 12 years and patients aged more than 12 year (33.5% vs 90.0%, log-rank P = 0.025). CONCLUSION: The early and intermediate outcomes of mitral valve repair with artificial chordae replacement were acceptable in children, and the outcomes were optimal in patients with simple lesions, and patients aged more than 12 years.

The catalytic pathways of hydrohalogenation over metal-free nitrogen-doped carbon nanotubes.

Nitrogen-doped carbon nanotubes (N-CNTs) are found to be active as one novel heterogeneous catalyst for acetylene hydrochlorination reaction, possessing good activity (TOF=2.3×10(-3) s(-1) ) and high selectivity (>98 %). Compared to toxic and energy-consuming conventional catalysts, such as HgCl2 , N-CNTs are more favorable in terms of sustainability, because of their thermo-stability, metal-free make up, and the wide availability of bulk CNT. Coupling X-ray photoelectron spectroscopy and density functional theory computations (DFT), the main active source and reaction pathway are shown. Good linearity between the quaternary nitrogen content and conversion is revealed. DFT study shows that the nitrogen doping enhanced the formation of the covalent bond between C2 H2 and NCNT compared with the undoped CNT, and therefore promoted the addition reaction of the C2 H2 and HCl into C2 H3 Cl.

Surgical treatment for primary mitral valve tumor: a 25-year single-center experience.

OBJECTIVE: Primary mitral valve (MV) tumor is a rare lesion, and to date, there have been few larger surgical series of MV tumors. We retrospectively analyzed 11 cases of primary MV tumors regarding clinical and pathological features, surgical procedure and long-term outcomes. METHODS: From November 1983 to December 2008, we operated on 11 patients (age 36.3 ± 17.7 years, weight 55.4 ± 11.2 kg) with primary MV tumors. Symptoms were cardiac in 8 cases (72.7%) and neurologic in 3 (26.3%). Surgical procedures included en bloc excision and MV repair in 8 cases and tumor resection and MV replacement in 3. No radiotherapy or chemotherapy was given to patients with malignant tumors. RESULTS: Pathological diagnosis was papillary fibroelastoma in 3 cases, myxoma in 3, lymphangioma in 1, lipoma in 1, hemangioma in 1 and sarcoma in 2. No early deaths or complications occurred. Late death occurred in 2 patients with sarcoma 1 year postoperatively. At the latest follow-up, with a maximum of 25 years (mean 10.6 ± 8.8), the 9 survivors were in New York Heart Association functional class I with normal MV function and no echocardiographic evidence of local recurrence. CONCLUSIONS: The majority of primary MV tumors are benign. They can cause cardiac or neurologic symptoms and should be excised as soon as a diagnosis is made. For benign tumors, valve-sparing resection and valve repair are often possible with excellent long-term outcomes. The prognosis of malignant MV tumors is poor.

Surgical and transcatheter closure of right pulmonary artery to left atrial fistula.

BACKGROUND AND AIM OF THE STUDY: Right pulmonary artery to left atrium fistula is a very rare cardiac malformation. We sought to describe our experience with surgical and transcatheter treatment of this defect in three cases. MATERIAL AND METHODS: Between October 2000 and October 2009, three patients with right pulmonary artery to left atrial fistula were treated at our institute. They were all males and aged 23, 7, and 14, respectively. They presented with cyanosis with clubbing of fingers and toes in three cases, and exertional dyspnea in two. Laboratory tests showed elevated hemoglobin and decreased systemic arterial oxygen saturation. Preoperative diagnosis was made by echocardiography and cardioangiography. The fistula was closed surgically in two patients either by simple ligation without cardiopulmonary bypass or by suture of the fistula from inside the right pulmonary artery lumen under cardiopulmonary bypass. In the third patient, the fistula was occluded with an 18-mm Amplatzer septal occluder (AGA Medical, Plymouth, MN, USA). RESULTS: The systemic oxygen saturation rose up to above 96% immediately after the procedures. No operative or procedural complication and late deaths occurred. All three patients were asymptomatic on follow-up. CONCLUSIONS: Both surgical and transcatheter closure are safe and reliable treatment for patients with right pulmonary artery to left atrial fistula. The treatment should be individualized and performed as soon as the diagnosis is made.

Surgical treatment of traumatic tricuspid insufficiency: experience in 13 cases.

BACKGROUND: Traumatic tricuspid insufficiency (TTI) is uncommon and surgical experience is limited. We report our surgical experience with TTI in 13 patients. METHODS: From January 2000 through March 2008, we operated on 13 patients with TTI (10 men 3 women; mean age, 39.8 ± 10.5 years). The intervals from trauma to diagnosis and from trauma to surgery averaged 37.4 and 54.4 months, respectively. At operation, the mechanism of TTI was due to anterior chordal rupture in 8, anterior papillary muscle rupture in 3, rupture of anterior papillary muscle and chordae in 1, and anterior leaflet defect in 1. In 7 patients the annulus was dilated. Valve repair was successful in 13 patients. RESULTS: No early or late deaths occurred. Severe hemolysis occurred in 1 patient after tricuspid and mitral valve repairs. At follow-up extending to 9.5 years, 9 patients were in New York Heart Association functional class I, and 4 were in class II. Transthoracic echocardiography demonstrated no or trivial residual regurgitation in 7 patients, mild regurgitation in 4, and mild-to-moderate regurgitation in 2. A significant decrease of the right ventricular end-diastolic dimension (37.7 ± 9.7 vs 20.7 ± 4.6 mm; p < 0.001) was observed. The mean transvalvular gradient was 2.5 ± 0.8 mm Hg. Eleven patients were in sinus rhythm. CONCLUSIONS: Satisfactory early and midterm outcomes can be achieved for TTI by tricuspid valve repair. Early surgical intervention should be emphasized to achieve good functional results and preserve the right ventricular function.

[Combined palliative procedures for cyanotic congenital heart defects with intractable hypoplasia of pulmonary arteries].

OBJECTIVE: To explore the clinical experiences of combined palliative procedures for cyanotic congenital heart defects with intractable hypoplasia of pulmonary arteries. METHODS: From August 2001 to September 2009, 31 patients with cyanotic congenital heart defects and intractable hypoplasia of pulmonary arteries underwent surgical procedures. Among them, 26 patients were pulmonary atresia with ventricular septal defect and the other 5 cases complicated congenital heart defects with pulmonary stenosis. Different kinds of palliative procedures were performed according to the morphology of right and left pulmonary arteries in every patient. If the pulmonary artery was well developed, Glenn procedure was performed. Modified Blalock-Taussig or Waterston shunt was performed if pulmonary arteries had hypoplasia. If the pulmonary arteries were of severe hypoplasia, Melbourne shunt was performed. Systemic-pulmonary artery shunts were performed bilaterally in 23 cases. Systemic-pulmonary shunt was performed in one side and Glenn procedure contralaterally in 8 cases. RESULTS: There was one early death because of cardiac arrest. The number of patients suffered from low cardiac output syndrome, perfusion lung and pulmonary infection postoperatively was 5, 3 and 2, respectively. Systemic-pulmonary shunts were reperformed after the original operation in 3 cases because of occlusion of conduits. The mean follow-up time was 25 ± 16 months (6 - 72 months). Left pulmonary index (8.1 ± 3.7 vs 14.9 ± 6.2), right pulmonary index (12.7 ± 8.1 vs 17.7 ± 7.8) and pulmonary index (20.9 ± 9.4 vs 32.6 ± 11.7) increased significantly (all P < 0.001). The pulmonary diameter increased significantly after modified Blalock-Taussig shunt (5.5 ± 1.0 vs 7.0 ± 2.0), modified Waterston shunt (5.7 ± 4.0 vs 9.2 ± 3.6) and melbourne shunt (2.2 ± 0.4 vs 7.4 ± 2.5) (all P < 0.05). Bilateral pulmonary arteries developed well compared with that of preoperative condition. Hemoglobin decreased from (194 ± 27) g/L to (174 ± 24) g/L (P < 0.05) and peripheral oxygen saturation increased from (65 ± 11)% to (84 ± 6)% (P < 0.001). During the follow-up ultimate complete repair were performed in 3 cases and one patients underwent Glenn procedure. CONCLUSIONS: The procedures should be considered for hypoplasia of pulmonary arteries in cyanotic congenital heart defects. Combined palliative operation is an adequate therapy.

Gas flow-assisted alignment of super long electrospun nanofibers.

Electrospinning provides a simple and versatile method for generating ultra thin fibers with diameters ranging from nanometer to micron out of various materials. However, there are still challenges in the alignment of electrospun nanofibers, which is an important step toward the exploitation of these fibers in applications. In this letter, we report a method using the gas flow to assist the alignment of electrospun nanofibers, which can form well-aligned super long polymeric nanofibers over large areas with the length of more than 20 cm. The improved collector is built by coupling a "T"-shaped electrode and a rectangle electrode, and it can make the electrospun nanofiber form a fixed site at the "T"-shaped electrode under the electric field and make it possible to use an assisting gas flow (AGF) to draw the other part of the nanofiber to fly toward the upside of the rectangle electrode and obtain well-aligned long nanofibers. These well-aligned long nanofibers can be further applied easily without disturbing the aligned structure, which is convenient for the measurement and device fabrications.

Improvement of Fe/MgO catalysts by calcination for the growth of single- and double-walled carbon nanotubes.

Calcination at 900-1000 degrees C for 8-12 h of an Fe/MgO catalyst prepared by impregnation was found to result in a uniform MgFe2O4/MgO solid solution that showed a successful settling of well-dispersed iron species into the MgO lattice. During methane reduction, many iron-containing particles with a diameter of about 4 nm were formed on the catalyst surface to provide numerous active sites for the growth of single- and double-walled carbon nanotubes. There was a significant improvement of the Fe/MgO catalyst that resulted in a high yield of impurity-free nanotubes. Using C2H4 cracking at 600 degrees C and transmission electron microscope observations, the Fe species distribution in the catalysts and microscope images of nanotube growth were described in detail. H2 reduction of the calcined Fe/MgO catalyst was found to cause the formation of iron layers on the catalyst surface, which resulted in the growth of only carbon layers. The results are useful for understanding changes in the metal species distribution in the catalysts and the nanotube growth mechanism, and they provide a simple method to improve Fe/MgO catalysts.

[Surgical treatment of giant coronary artery aneurysm].

OBJECTIVE: To discuss the clinical features and surgical treatments of giant coronary artery aneurysm (CAA). METHODS: From July 1996 to October 2004, 6 giant CAA patients were underwent surgery at Fuwai hospital. Three cases were underwent CAA resection, 2 concomitant coronary bypass, 3 reconstruction. The giant CAA was often combined with other cardiac diseases. Four cases underwent additional procedures of fistula closure, 3 aortic valve replacements, 2 aortoplasty and 1 thrombus cleaning at the same time. RESULTS: All patients recovered uneventfully. The mean of cardiopulmonary bypass time was (144 +/- 26) min (range 67 to 207 min). Aortic cross clamping time was (104 +/- 21) min (range 56 to 172 min). Patients follow-up time occurred from 8 to 87 months (mean of 48 months). All patients were free of symptoms during follow-up. None of the patients died during the follow-up period and none of the CAA recurred. CONCLUSIONS: The giant CAA is a serious cardiovascular disease, early diagnosis and surgical treatment are mandatory.

Surgical treatment of giant coronary artery aneurysm.

OBJECTIVE: Giant coronary artery aneurysm is an extremely uncommon disease. Most previous reports have involved only single cases. This report describes 6 patients with giant coronary artery aneurysm, examines its causes, and aims to establish the optimal surgical strategies for this exceptional and rare pathology. METHODS: From July 1996 to October 2004, a total of 30,268 patients underwent heart surgery at Fuwai Hospital in Beijing. Among these, 6 patients had giant coronary artery aneurysm diagnosed and underwent operation. Various surgical strategies were used for the operations of these 6 patients, such as coronary artery aneurysm resection, coronary artery reconstruction, and concomitant coronary bypass. Additional procedures, such as fistula closure, aortic valve replacement, aortoplasty, and embolectomy, were done at same time for the patients with complications of coronary fistula, aortic valve insufficiency, or thrombus. Patients were followed up from 8 to 87 months, with a mean of 48 months. Doppler echocardiography, ultrafast computed tomography, and 3-dimensional aerial image studies were performed during follow-up. RESULTS: Five of these six cases were found combined with coronary artery fistula, and the cause for these giant coronary artery aneurysms was congenital. The remaining case was caused by atherosclerosis. After surgery, all patients recovered uneventfully, without in-hospital mortality. None died during the follow-up, nor did any have recurrence of the symptoms or giant coronary artery aneurysm. CONCLUSION: Giant coronary artery aneurysm is a rare entity that is commonly caused by congenital malformation and combined with other cardiac anomalies. An optimal surgical operation should be based on the specific cardiac anomaly of the individual patient.

Correction of traumatic tricuspid insufficiency using the double orifice technique.

Traumatic tricuspid insufficiency is an uncommon clinical condition and surgical procedures vary. In this paper we report our experience in treating traumatic tricuspid insufficiency using the double orifice technique. From January 2000 to September 2003, 10 patients with traumatic tricuspid regurgitation were admitted to our hospital, 5 of whom were corrected using the double orifice technique. There were 4 males and 1 female with ages ranging from 31 to 52 years. Preoperative transthoracic echocardiography (TTE) detected severe tricuspid regurgitation in 4 patients and moderate tricuspid regurgitation in 1 patient. At surgery, tear of the tricuspid anterior papillary muscle was found in 2 cases and anterior chordal rupture in 3 cases. The valves were successfully repaired using the double orifice technique in combination with ring annuloplasty. There was no repeat operation, no operative complications or deaths. Before discharge, TTE detected normal tricuspid valve function in 2 cases and tiny regurgitation in 3 cases. After a follow up of 8 to 36 months, TTE demonstrated normal valve function in 1 patient and tiny regurgitation in 4 patients. The double orifice technique appears to be a simple but effective method of repairing traumatic tricuspid incompetence. Satisfactory clinical outcomes can be produced in carefully selected patients.

Comparison of different approaches for pediatric congenital heart diseases.

To compare the clinical results of different surgical approaches for congenital heart disease in pediatric patients, 1669 cases of atrial septal defect, ventricular septal defect, or tetralogy of Fallot, which were corrected from January 1999 to December 2001, were classified according to approach (sternotomy, ministernotomy, or minithoracotomy). In cases of ventricular septal defect, the incidence of pulmonary complications was significantly higher in the minithoracotomy group than in the full sternotomy or ministernotomy groups. In patients with tetralogy of Fallot, hemoglobin concentration was higher, oxygen saturation was lower, and more patients required a transanular patch in the sternotomy group than in the other groups, but the clinical results were similar. Patients with complex defects or severe pulmonary hypertension should undergo a full sternotomy.