Hemodynamics-based numerical comparison between two options of modified B-T shunt / 医用生物力学

Objective To analyze and compare hemodynamic features of two different options for modified B-T shunt (MBTS) surgery, namely end-to-side(ETS) and side-to-side (STS), so as to provide references for clinical treatment of single ventricle heart defect syndrome. MethodsThe real geometric model was reconstructed by medical images obtained from a patient with hypoplastic left heart syndrome (HLHS); MBTS surgery was simulated through virtual operations; a lumped parameter model (LPM) was constructed based on physiological data of the patient; the post-operational boundary conditions of computational fluid dynamics (CFD) models (namely STS model and ETS model) were predicted based on the LPM; numerical simulation was conducted on two CFD models by using finite volume method. Results Flow details and wall shear stress distributions were all obtained for two models. The mean oscillatory shear index (OSI) of ETS model and STS model in part of pulmonary arteries was 3.058×10-3 and 13.624×10-3, respectively, while the energy loss was 116.5 and 94.8 mW, respectively, and blood flow rate ratios of left pulmonary artery to right pulmonary artery (RRPA/LPA) were 0.8 and 1.72, respectively. Conclusions There were nearly no differences between two CFD models in energy loss, which led to a relatively small impact on the surgery. The STS model had a more balanced pulmonary artery blood perfusion and a smaller mean OSI in part of pulmonary arteries, therefore, the STS model was superior to the ETS model. This study provides an important theoretical support and reference for treating patients with HLHS.

Numerical study on multiscale simulation for hemodynamics of systemic-pulmonary shunt procedure based on lattice Boltzmann method / 医用生物力学

Objective Based on time-coupled multiscale coupling algorithm, to simulate the hemodynamics after systemic-pulmonary shunt procedure on single ventricular patient so as to obtain the local three-dimensional (3D) fluid field and global hemodynamic information before and after surgery. MethodsFirstly, the 0D-3D coupled multiscale hemodynamic model of systemic-pulmonary shunt procedure was established based on the lumped parameter model (0D) before surgery and the shunt model (3D), then the 0D-3D interface coupling condition and the time coupling algorithm were discussed. Secondly, the multiscale simulation of 3D CFD (computational fluid dynamics) model coupled with 0D lumped parameter model was realized based on lattice Boltzmann method. Finally, the multiscale simulation results were compared with patient’s 0D simulation results to study the hemodynamic changes before and after surgery. Results The global hemodynamic change and local 3D flow pattern were obtained by this multiscale simulation. The pulmonary blood flow distribution ratio was increased from 32.21% to 57.8%. Conclusions The systemic-pulmonary shunt procedure can effectively increase the blood supply of pulmonary circulation by implanting the shunt between the systematic circulation and pulmonary circulation. The geometrical multiscale method can effectively simulate both the coarse global and detailed local cardiovascular hemodynamic changes, which is of great significance in pre-operation planning of cardiovascular surgery.

Mutation analysis and prenatal diagnosis of FBN1 gene mutations for four patients with Marfan syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To screen for mutations of fibrillin-1 (FBN1) gene in 4 patients with Marfan syndrome in order to provide prenatal diagnosis and genetic counseling.</p><p><b>METHODS</b>Potential mutations of the FBN1 gene in the probands were detected with PCR and DNA sequencing. Subsequently, genomic DNA was extracted from amniotic fluid sampled between 18 to 20 weeks gestation. The mutations were confirmed with denaturing high-performance liquid chromatography - robust microsatellite instability (DHPLC-MSI) analysis with maternal DNA as reference. The products were further analyzed by direct sequencing and BLAST search of NCBI database.</p><p><b>RESULTS</b>An IVS46+1G>A substitution was identified in patient A at +1 position of intron 46 of the FBN1 gene. Two novel missense mutations were respectively discovered at positions +4453 of intron 35 in patient B (Cys1485Gly) and position +2585 of intron 21 in patient C (Cys862Tyr). In patient D, a novel deletion (c.3536 delA) was found at position +3536 of intron 28. In all of the 4 cases, the same mutations have been identified in the fetuses.</p><p><b>CONCLUSION</b>FBN1 gene analysis can provide accurate diagnosis of Marfan syndrome, which can facilitate both prenatal diagnosis and genetic counseling.</p>

Efficacy of minimally invasive left ventricular epicardial lead placement for cardiac resynchronization therapy / 中华心血管病杂志

<p><b>OBJECTIVE</b>Ventricular resynchronization might be achieved via minimally invasive left ventricular epicardial lead placement.</p><p><b>METHOD</b>Six patients with congestive heart failure underwent minimally invasive left ventricular epicardial lead placement after failed coronary sinus cannulation were followed up for 1 year, cardiac function and LV lead threshold were evaluated.</p><p><b>RESULTS</b>There were no in-hospital deaths, intraoperative complications and diaphragm stimulation. Correct lead positioning was achieved in all 6 patients. LV lead thresholds remained unchanged [(1.2 ± 0.5) V vs (1.1 ± 0.4) V, P = 0.68] at 12 months follow-up. Improvements on 6 min walking test [(327 ± 77) m vs (267 ± 68) m, P = 0.001], LVEF [(26.1 ± 6.0)% vs (38.2 ± 4.7)%, P = 0.004], and NYHA functional class were evidenced at 12 months follow-up.</p><p><b>CONCLUSION</b>Minimally invasive left ventricular epicardial lead placement is a safe and reliable technique and should be considered as an alternative option in case of difficult coronary venous anatomy and inability to position the lead for resynchronization therapy.</p>

Clinical outcome of mitral valve repair in primary infective endocarditis with mitral insufficiency / 中华外科杂志

<p><b>OBJECTIVE</b>To study the clinical results of mitral valve repair in patients of primary infective endocarditis with mitral insufficiency.</p><p><b>METHODS</b>From January 2004 to July 2007, 40 patients who had undergone valve repair procedure for infective endocarditis with mitral insufficiency were analyzed retrospectively. There were 26 male and 14 female patients, with an average age of (34.0 +/- 3.5) years old, including 6 patients of underlying heart disease, 34 patients of no previously underlying heart disease. There were 12 patients in NYHA functional class II, 19 patients in class III, 9 patients in class IV preoperatively. Preoperative echocardiography showed moderate to severe MR in all patients. The surgery was performed under extracorporeal circulation and moderate hypothermia. The distribution of anatomical lesion according to surgical findings were vegetation in 32 patients, leaflet prolapsed in 34 patients, leaflet perforation in 16 patients, chordal rupture in 32 patients, and annular abscess in 2 patients. The vegetations and infected tissues were debrided. The surgery consisted of complex methods to repair mitral valve, including direction leaflet closure in 5 patients, pericardial patch closure of leaflet perforation in 18 patients, chords reimplantation in 4 patients and chords transference in 6 patients, quadrangular resection in 12 patients, double orifice method in 17, closure of the commissure in 8, rings annuloplasty in 28 cases, and so on. There were 28 selective surgeries and 12 emergent ones. Patients were evaluated for early and long-term clinic and echocardiographic outcome before and after operation.</p><p><b>RESULTS</b>There were no early postoperative death. Mitral valve repair was feasible in 39 patients, one patient was transformed to mitral valve replacement during the operation. Postoperative echocardiography demonstrated no (n = 24) or mild (n = 15) mitral regurgitation at the discharge examination and observed significant reductions in left ventricular end diastolic [from (62 +/- 7) mm to (51 +/- 6) mm, P < 0.05] and end systolic dimensions [from (45 +/- 3) mm to (40 +/- 4) mm, P < 0.05] and left atrial dimensions [from (49 +/- 4) mm to (42 +/- 6) mm, P < 0.05]. Mean follow-up (25.6 +/- 3.2) months, freedom from recurrent moderate to severe MR, freedom from repeat operation or infective endocarditis, revealed patients were 36 cases in NYHY class I, 3 cases in class II.</p><p><b>CONCLUSION</b>Mitral valve repair for mitral valve endocarditis is feasible with a satisfied clinical outcome, maintains valve competency with significant reductions in left atrial and left ventricular dimensions after surgery.</p>

Clinical analysis of pregnancy and postpartum cardiovascular complications in Marfan syndrome / 中华妇产科杂志

Objective To investigate the management of pregnancy and cardiovascular complications in women with Marian syndrome(MFS).Methods From October 1994 to September 2006, 30 patients with MFS undergoing cardiovascular surgery were studied retrospectively.Results In the labor of 46 offsprings given birth by 30 women,5 cases(11%)were performed elective cesarean section because of the existence of aortic complication,and 12(26%)were diagnosed as MFS.The gestation in two patients was terminated due to deterioration of aortic abnormalities during their third trimester,and they received surgical treatment with Bcntall procedure.Two developed acute aortic dissection during labor and post delivery respectively.With the manipulation of anticoagulation peripartum,one who had the implantation with mechanical prosthesis went through pregnancy and delivery uneventfully.The average duration between delivery and cardiovascular surgery was(15?9)years.Conclusions Vaginal delivery can be done safely in patients with the MFS who do not have or have mild cardiovascular system abnormalities,aortic dissection,or other important cardiac abnormalities,cesarean section should be the preferred method of delivery.Women with MFS are at increased risk for dissection and congestive heart failure during pregnancy and should be counseled before pregnancy about these risks,as well as the inheritance of the condition.