10.3969/j.issn.2095-4344.2013.25.026

10.3969/j.issn.2095-4344.2013.23.022

Objective:To reconstruct middle ear structure for open mastoid antrum with external auditorycanal after radical mastoidectomy in one-stage. Method: 71 ears of post-mastoidectomy (discharging 53 ears anddried up 18 ears) were undergone with reconstruction of middle ear. The posterior wall of external auditorycanal, mastoid cavity and chain of ossicles were reconstructed with homologous costal cartilage. Result: 69 ears of71 cases were near normal structure followed up 6 months to 5 years after operations. The result showed hearingimprovement over 15 dB were 55 ears (77.5％) and under 15 dB were 11 cases (15.5％). Five cases (7.0％)were failed. Conclusion: Reconstruction of middle ear with homologous costal cartilage is a ideal surgery toreconstruct hearing structure and avoid infection of middle cavity after radical mastoidectomy.

BACKGROUND:The artificial heart valve used in clinical application can be divided into stented and stentless. Stented valve is convenient for operations, with a low possibility of incompetency after transplantation. However stented valve cannot stimulate natural valve. OBJECTIVE:To reduce valve implantation time and improve valve properties, this study was designed to develop a new stentless porcine aortic valve for single-layer suture and implantation based on the design of valve in pig aortic root geometry optimization, and to further evaluate its performance by in vitro test. METHODS:(1) Stentless porcine aortic valve for single-layer suture was prepared. (2) The in vitro valve implantation experiment was performed with monolayer suture method. (3) The valve was detected by in vitro fluid mechanics test and fatigue test. RESULTS AND CONCLUSION:Stentless valve for single-layer suture has removed the valve hard, which contributes to reduce the damaged caused by blood flow on the valve leaflet, at the same time removal of the hard valve ring can widen the diameter of implanted valve and improve hemodynamics, even the implantation time of valve is shorter than traditional double-layer suture. The in vitro fluid mechanics test and fatigue test results are satisfactory. The future research lies in a complete elucidation of long operation time, postoperative long-term clinical efficacy and durability of stentless valve implantation.

Objective: To explore the impact of Ischemic preconditioning (IPC) in aged experimental rats after myocardial ischemia-reperfusion (I/R) with its mechanism.
Methods: A total of 32 Wistar rats at the age of (21-23) months were divided into 4 groups, n=8 in each group.①Control group, the rats received cardiac perfusion for 180 min. ②I/R group, the rats received cardiac perfusion for 30 min, followed by ischemia for 30 min, then reperfusion for 120min.③IPC group, the rats received cardiac perfusion for 10 min, followed by ischemia and reperfusion 2 times (5 min in each time), then ischemia 30 min and reperfusion 120 min. ④ Enhanced IPC group, rats received cardiac perfusion for 10 min, followed by ischemia and reperfusion 4 times (5 min in each time), then ischemia 30 min and reperfusion 120 min. The recovery rate of cardiac output (CO), left ventricular developed pressure (LVDP) and the recovery rate of maximum rise and fall of left ventricular pressure (±dp/dtmax) at (30, 60, 90, 120) min after reperfusion were recorded respectively. The creatine kinase (CK-MB), superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were examined before ischemia and 120 min after reperfusion. The apical peroxisome proliferator-activated receptorγco-stimulatory factor 1α(PGC-1α) was examined by immuno-histochemistry.
Results: The MDA content, CK-MB, SOD activities LVDP and (±dp/dtmax) recovery were similar between IPC group and I/R group, P>0.05. While compared with I/R group, the Enhanced IPC group showed decreased CK-MB activity and MDA content, increased SOD activity and CO, LVDP and (±dp/dtmax) recovery rate, all P<0.01. The PGC-1αexpression was similar between IPC group and I/R group, P>0.05. While compared with I/R group, the Enhanced IPC group had increased PGC-1αexpression, P<0.01.
Conclusion: The cardiac IPC was weakened in aged rats which might be because of decreased PGC-1αexpression, the enhanced IPC may up-regulate PGC-1αexpression and therefore, protect the cardiac tissue in aged experimental rats.

BACKGROUND:Artificial chordae transplantation and saddle ring annuloplasty are the key steps in mitral valvuloplasty. However, there are no large-size studies addressing the safety, validity and efficacy of these treatments in China.
OBJECTIVE:To summarize the efficacy and safety of artificial chordae transplantation and saddle ring annuloplasty in the treatment of degenerative mitral regurgitation.
METHODS:Eighty-five patients with degenerative mitral regurgitation underwent mitral valve repair with artificial chordae (Gore-Tex sutures) transplantation and saddle ring (SJMTM rigid saddle-shaped) annuloplasty from January 2009 to May 2013 in General Hospital of Shenyang Area Military Command, China. Operative technique included simple artificial chordae transplantation in 41 cases, artificial chordae transplantation plus quadrangular resection of the posterior leaflet in 22 cases, artificial chordae transplantation plus quadrangular resection of the posterior leaflet and sliding technique in 23 cases. Al cases received saddle ring annuloplasty.
RESULTS AND CONCLUSION:Fol ow-up after treatment was done among 78 patients for 6 months to 4 years, with a fol ow-up rate of 91.7%(78/85). Among the 78 cases, one case died of cerebral infarction after 13 months, one died from accident, and the remaining 76 were alive. According to the evaluation of cardiac function (NYHA), 59 cases were in grade I and 17 cases were in grade II. Color ultrasound displayed that, no regurgitation was found in 67 cases, and mild regurgitation in 9 cases. The echocardiography showed that postoperative left atrium diameter (P<0.05 or P<0.01), left ventricular end-diastolic diameter (P<0.05 or P<0.01), left ventricular end-systolic diameter (P<0.05 or P<0.01), and the ratio of regurgitation beam area and left atrial area (P<0.05 or P<0.01), mean pulmonary artery pressure (P<0.05 or P<0.01) were significantly decreased compared with that before operation. Ejection fraction was significantly increased after operation (P<0.05 or P<0.01). No systolic anterior motion occurred. The postoperative complications included sinus bradycardia in 12 cases and paroxysmal supraventricular tachycardia in 25 cases, late cardiac tamponade in 1 case at 1 week postoperatively, and pacemarker implantation in 1 case (who exhibited bradycardia-tachycardia syndrome before operation). There was no ring rupture, ring avulsion, hemolysis, left ventricular outflow tract infarction and artificial chordae rupture or splitting. No cases needed reoperation on valve replacement. Application of artificial chordae transplantation and saddle ring annuloplasty is a safe and effective means for treating degenerative mitral regurgitation, with excellent midterm outcomes.

Objective To summarize the prevention and treatment experience of complications of cardiac myxoma excision.Methods Cardiac myxoma excision were performed in 215 cases under general anesthesia,cardiopulmonary bypass and cardiac arrest condition.Results Two cases died from severe low cardiac output syndrome which eventually caused multiple organ failure.The remaining 213 cases were cured and discharged.Among 213 cases,low cardiac output syndrome occurred in 35 cases,re-open chest for bleeding was performed in 8 cases,30 cases in arrhythmia (including paroxysmal supraventricular tachycardia in 20 cases and ventricular premature in 10 cases),no vital organs embolism occurred.Follow-up was done to 200 patients for 1-8 years with a follow-up rate of 93.9％ (200/213).In 200 cases,1 case died from lung cancer,1 case recurred and was cured after re-operation.The remaining patients had no obvious abnormalities.Conclusion As the particularity of surgical treatment of cardiac myxoma,it is essential to take prevention measures to reduce complications of cardiac myxoma excision in perioperative periods.

Objective To summarize the treatment experience of supraventricular tachycardia (SVT) after coronary artery bypass graft (CABG). Methods The clinical data of 136 patients who had occurred SVT after CABG between January 2008 and December 2009 were analyzed retrospectively. Results Among 136 patients,no perioperative mortality,atrial fibrillation (AF) occurred in 110 cases (80.88%),paroxysmal supraventricular tachycardia (PSVT) occurred in18 cases ( 13.24% ), atrial flutter occurred in 8 cases (5.88%),112 of 136 cases occurred in 1-3 days after surgery,accounting for 82.35% ,24 cases occurred in 4-7 days after surgery,accounting for 17.65%. Given amiodarone in the treatment of 105 cases,100 cases reverted to sinus rhythm (cardioversion rate of 95.24% ),given esmolol in the treatment of 11 cases, 9 cases reverted to sinus rhythm( cardioversion rate of 81.82% ), synchronous direct current cardioversion in 20 cases, all transferred to sinus rhythm, all patients with improved symptoms. The remaining failed to transfer to sinus rhythm, had got normal ventricular rate, and symptoms improved significantly. Conclusions It is necessary to take effective measures to prevent SVT within 3 days after CABG. Amiodarone, esmolol and synchronous direct current cardioversion can be used effectively and safely to control SVT after CABG.

Objective To summarize the experience of application of artificial chordae transplantation in mitral valve repair.Methods One hundred and five patients with mitral regurgitation due to mitral degeneration,underwent mitral valve repair with artificial chordae transplantation.Operative technique included simple Gore-Tex artificial chordae transplantation in 25 cases,artificial chordae transplantation plus quadrangular resection of the posterior leaflet in 67 cases,artificial chordae transplantation plus quadrangular resection of the posterior leaflet and Sliding technique in 13 cases.Results No early death occurred after operation.The postoperative complications were caused in 30 patients including sinus bradycardia in 8 cases,supraventricular tachycardia in 20 cases,late cardiac tamponade in onecase,pacemarker implantation in one case.Hospital time was 9-21 (14 ±4) d.Follow-up was done to 96 patients for 3 months to 5 years with a follow-up rate of 91.4％(96/105).Among 96 cases,one died of cerebral infarction after 13 months,one died from accident while the remaining were alive,74 cases were with cardiac function (NYHA) of grade Ⅰ and 20 cases with grade Ⅱ.No regurgitation was found in 92 cases,mild regurgitation in 2 cases.There were no artificial chordae ruptures.Conclusions The key to improve the early and midterm results of artificial chordae transplantation are to choose patients strictly,to grasp proper surgical skills,to do a good job in intraoperative shaping effect evaluation and the myocardial protection during extracorporeal circulation.

Objective To study the long-term effect of total right heart bypass on pulmonary perfusion after extracardiac total cavopulmonary connection (ETCPC).Methods Fifty-three patients (29males,24 females; average age (10.8±6.1) years) undergoing ETCPC from March 1990 to December 2005were retrospectively analyzed.Forty-three patients had full set of pulmonary perfusion data at 1 month and 5years postoperation.The perfusion ratios of each lung segment were calculated based on 99Tcm-MAA radionuclide imaging.The PVR and pulmonary artery index were calculated from angiocardiography measurements.All data were compared with paired t test.Results Compared with the early postoperative data,the perfusion ratio of superior/inferior segment(0.72±0.20 vs 0.75±0.01; t =2.54,P＜0.05),the PVR ((142.98±2.61) vs (146.95±2.54) dyn · s · cm-5; t=2.08,P＜0.05; 1 dyn · s · cm-5 =0.1 kPa · s · L-1) and vena cava pressure ((9.35±0.24) vs (9.95±0.23) mmHg; t=2.69,P＜0.05; 1 mmHg=0.133 kPa) decreased significantly in follow-up data; while the ratio of posterior basal segment perfusion increased significantly (0.12±0.00 vs 0.10±0.03; t=2.16,P＜0.05).The arterial oxygen saturation ((92.70±0.30)％ vs (92.86±0.29) ％ ; t =1.12,P＞0.05),the total pulmonary nuclear counts ((701.91 ± 8.26) × 103 vs (698.93 ± 12.0) ×103 ; t=0.38,P＞0.05) and the perfusion ratio of inferior vena cava to the right lung (0.61±0.06 vs 0.60±0.06 ; t =0.74,P ＞ 0.05) were similar between the two terms of follow-up.The early angiographic and radionuclide perfusion studies did not match in 5 patients.Conclusions Hypostatic redistribution of pulmonary blood flow is the characteristics in long-term follow-up of ETCPC patients.The radionuclide imaging is superior to angiocardiography in revealing functional pulmonary blood perfusion.