High-sensitivity troponin T levels before and after cardiac surgery and the 30-day mortality: a retrospective cohort study.

Background: The suggested threshold level of cardiac troponin T elevation after cardiac surgery is not very clear, and the values recommended by various guidelines and literature reports are quite different. Methods: In this retrospective cohort study, we collected clinical data of patients who underwent heart surgery at Tsinghua University First Hospital between January 2015 and December 2022. Using the high-sensitivity cardiac troponin T levels (reference upper limit: 14 ng/L) measured at 1-3 days postoperation, the relationship between the cardiac troponin T level and the 30-day mortality risk was evaluated using Cox regression analysis. Results: Among the 3,128 patients included in this study, the types of operations mainly consisted of coronary artery bypass graft (CABG, 1,164, 37.2%), aortic valve replacement (AVR, 735, 23.5%), and other cardiac operations (1,229, 39.3%). Within 30 days postoperation, 57 patients (1.8%) died and 72 patients (2.3%) developed major vascular complications. In patients undergoing CABG or AVR, the cardiac troponin T threshold level measured within one day postoperation related to an increased 30-day mortality was determined to be 3,012 ng/L (95% CI: 1,435-3,578 ng/L), which is 218 times higher than the reference upper limit. In patients undergoing other cardiac operations, this threshold was 5,876 ng/L (95% CI: 2,458-8,119 ng/L), which is 420 times higher than the reference upper limit. Conclusion: The high-sensitivity cardiac troponin T level associated with an increased 30-day mortality risk after cardiac surgery is significantly higher than the current recommendations for defining clinically important perioperative myocardial injury.

Surgical strategies and outcomes for myocardial bridges coexisting with other cardiac conditions.

BACKGROUND: Myocardial bridges are congenital coronary artery anomalies. There are still many controversies surrounding surgical treatment strategies for myocardial bridges combined with other heart disorders. The purpose of this study was to evaluate the surgical treatment strategies and outcomes in patients with these conditions. METHODS: Between March 2004 and October 2021, our institution witnessed 77 patients diagnosed with myocardial bridging who underwent surgical intervention. According to the myocardial bridge and combined heart disorder, four groups were identified: 1. isolated LAD supra-arterial myotomy group, 2. LAD CABG and(or not) myotomy  group, 3. LAD supra-arterial myotomy and grafting of other branches group, and 4. LAD supra-arterial myotomy and other cardiac surgery group. The perioperative outcomes, symptoms, life quality, mortality, and major adverse cardiac events (MACEs) were analyzed. RESULTS: There were no deaths during hospitalization and no rethoractomy for postoperative bleeding or major adverse cardiac events (MACEs). The follow-up period ranged from 2 months to 199.2 months (55.61 ± 10.21) months, the 10-year cumulative survival rates for the four groups of patients were 95.0%, 100%, 100% and 74.1%, and the 10-year freedom rates from the MACEs were 83.9%, 92.0%, 87.5% and 76.2%, respectively. CONCLUSIONS: Supra-arterial myotomy is preferred in patients with isolated myocardial bridge, and acceptable results can be achieved by choosing supra-arterial myotomy in combination with CABG or other cardiac surgery simultaneously for patients with myocardial bridges and other heart disorders.

Left ventricular pacing in the treatment of pediatric cardiac dysfunction caused by idiopathic complete left bundle branch block.

OBJECTIVE: This study aimed to investigate the feasibility and effectiveness of transthoracic epicardial dual-chamber pacemaker implantation in the treatment of cardiac dysfunction caused by idiopathic complete left bundle branch block (CLBBB) in children. METHODS: Nine children diagnosed with cardiac dysfunction due to idiopathic CLBBB were included in this study. All patients underwent transthoracic epicardial dual-chamber pacemaker implantation. Cardiac function was evaluated using echocardiography during the follow-up. Additionally, intraventricular synchronization parameters were assessed using two-dimensional speckle tracking echocardiography (STE). RESULTS: Nine children (mean age, 3.0 ± 2.6 years) were included in this study. The median follow-up duration was 2 (interquartile range, 1-3) years. The cardiac function of all patients recovered to normal levels within 1 year postoperatively. The postoperative QRS duration on electrocardiography (142 ± 21 ms) was significantly shorter than that at baseline (106 ± 12 ms) (p < .05). Cardiac dyssynchrony in patients who manifested preoperatively achieved complete correction after pacemaker implantation. The comparison of preoperative and postoperative (last follow-up visit) synchronization parameters were as follows: longitudinal standard deviation of the time to peak strain, 99.0 ± 41.9 versus 36.8 ± 5.0 ms (p = .004); delay time of peak longitudinal strain, 252.2 ± 131.4 versus 35.0 ± 22.9 ms (p = .002); and longitudinal systolic dyssynchrony index, 2.8 ± 0.8% versus 1.0 ± 0.3% (p = .001), respectively. CONCLUSION: Transthoracic epicardial dual-chamber pacemaker implantation (with left atrial sensing and left ventricular single-site pacing) can be used for the treatment of cardiac dysfunction caused by idiopathic CLBBB in children.

Preclinical study of human umbilical cord mesenchymal stem cell sheets for the recovery of ischemic heart tissue.

BACKGROUND: Human umbilical cord mesenchymal stem cells (hUC-MSCs) have been widely used due to their multipotency, a broad range of sources, painless collection, and compliance with standard amplification. Cell sheet technology is a tissue engineering methodology requiring scaffolds free, and it provides an effective method for cell transplantation. To improve the therapeutic efficacy, we combined hUC-MSCs with cell sheet technology to evaluate the safety and efficacy of hUC-MSC sheets in preclinical studies using appropriate animal models. METHODS: hUC-MSC sheets were fabricated by hUC-MSCs from a cell bank established by a standard operation process and quality control. Cytokine secretion, immunoregulation, and angiopoiesis were evaluated in vitro. Oncogenicity and cell diffusion assays of hUC-MSC sheets were conducted to verify the safety of hUC-MSCs sheet transplantation in mice. To provide more meaningful animal experimental data for clinical trials, porcine myocardial infarction (MI) models were established by constriction of the left circumflex, and hUC-MSC sheets were transplanted onto the ischemic area of the heart tissue. Cardiac function was evaluated and compared between the experimental and MI groups. RESULTS: The in vitro results showed that hUC-MSC sheets could secrete multiple cellular factors, including VEGF, HGF, IL-6, and IL-8. Peripheral blood mononuclear cells had a lower proliferation rate and lower TNF-α secretion when co-cultured with hUC-MSC sheets. TH1 cells had a smaller proportion after activation. In vivo safety results showed that the hUC-MSCs sheet had no oncogenicity and was mainly distributed on the surface of the ischemic myocardial tissue. Echocardiography showed that hUC-MSC sheets effectively improved the left ventricular ejection fraction (LVEF), and the LVEF significantly changed (42.25 ± 1.23% vs. 66.9 ± 1.10%) in the hUC-MSC transplantation group compared with the MI group (42.52 ± 0.65% vs. 39.55 ± 1.97%) at 9 weeks. The infarct ratio of the hUC-MSCs sheet transplantation groups was also significantly reduced (14.2 ± 4.53% vs. 4.00 ± 2.00%) compared with that of the MI group. CONCLUSION: Allogeneic source and cell bank established by the standard operation process and quality control make hUC-MSCs sheet possible to treat MI by off-the-shelf drug with universal quality instead of individualized medical technology.

Types of vertebral fractures could influence the selection of clinical bone mineral measures to predict biomechanical properties.

Areal and volumetric BMD (aBMD and vBMD) measured by DXA and quantitative CT (QCT), respectively, are usually employed to predict vertebral fracture risks. In this study, we induced compression and wedge vertebral fractures to test if the types of fracture could influence the selection of bone mineral measures to predict biomechanical properties of vertebral bodies. DXA and QCT were employed to scan twenty-four male cadaveric vertebral bodies of humans for bone mineral content (BMC) and aBMD measures, and vBMD measures, respectively. We computed vBMD measures from three kinds of volumes of interest: intact structures (vertebral body, cortical compartment, and trabecular core), axially middle sections (1.250-1.875 cm height) of the intact structures, and clinically used elliptical regions of trabecular bone. We loaded vertebral bodies to failure for properties of strength (Pu), failure displacement (δu), and stiffness (K). Thirteen vertebral bodies sustained compression fractures and the remaining sustained wedge fractures. Linear and power regression models were used to test bone mineral predictions for Pu, δu, and K. We also did equality tests of correlation coefficients. Our results showed aBMD, BMC, and vBMD of the middle section of trabecular bone had the strongest correlations with Pu (R2 = 0.6420, p < 0.001), δu (R2 = 0.4619, p < 0.001), and K (R2 = 0.5992, p < 0.001) in power regression models, respectively when compression and wedge fractures were mixed. Considering compression fractures only, vBMD of the intact vertebral body displayed the strongest correlations with both Pu (R2 = 0.6529, p < 0.001) and K (R2 = 0.6354, p < 0.001) while BMC showed the strongest correlation with δu (R2 = 0.4376, p < 0.001) in linear regression models. When only wedge fractures were analyzed, vBMD of the elliptical regions of trabecular bone exhibited the strongest correlations with both Pu (R2 = 0.5845, p < 0.001) and K (R2 = 0.6420, p < 0.001) in power regression models, however, no bone mineral measure could significantly correlate with δu. These results may suggest the type of fracture could influence the determination of bone mineral measures to predict biomechanical properties of vertebral bodies.

Surgical intervention and outcome for treatment of myocardial bridging refractory to medication.

INTRODUCTION: Myocardial bridging (MB) is a common and usually benign inborn coronary abnormality that may lead to anginal symptoms, acute coronary syndrome, arrhythmias, and rarely sudden cardiac death. MB are most commonly localized in the middle segment of the left anterior descending coronary artery (LAD). The treatment of LAD-MB is still challenging. Our objective was to assess the short- and long-term results of surgical procedures in patients with LAD-MB who had chest pain refractory to medical therapy. METHODS: Between March 2005 and January 2020, 26 patients (19 males and 7 females; mean 55.8 ± 12.4 years) with MB underwent surgery. All MB was located in the mid-segment of the LAD with a mean length of 4.2 ± 1.7 cm. Coronary angiography before surgery demonstrated LAD-MB with systolic compression more than or equal to 70% in all patients. RESULTS: Twenty-five patients underwent myotomy and one patient underwent coronary artery bypass grafting (CABG). All patients survived and recovered uneventfully. Neither hospital or late death nor major complications occurred. Follow-up time was 3-173 months (mean 55.7 months). Follow-up of coronary angiography or computed tomography scan performed in 16 patients demonstrated restoration of coronary blood flow and myocardial perfusion without significant residual compression of the artery. All patients were symptom-free and are currently in NYHA Class I. CONCLUSION: The symptomatic LAD-MB patients who are refractory to medication should actively undergo the surgical intervention such as myotomy and CABG to eliminate the clinical symptoms and achieve satisfactory results by follow-up findings. Myotomy is a preferred procedure because of its safety and satisfactory results.

Application of mesenchymal stem cell sheet to treatment of ischemic heart disease.

In recent years, mesenchymal stem cells (MSCs) have been used to improve cardiac function and attenuate adverse ventricular remodeling of the ischemic myocardium through paracrine effects and immunoregulation functions. In combination with cell sheet technology, MSCs could be more easily transplanted to the ischemic area. The long-term retention of MSCs in the affected area was realized and significantly improved the curative effect. In this review, we summarized the research and the applications of MSC sheets to the treatment of ischemic heart tissue. At present, many types of MSCs have been considered as multipotent cells in the treatment of heart failure, such as bone marrow-derived mesenchymal stem cells (BM-MSCs), adipose-derived mesenchymal stem cells (AD-MSCs), umbilical cord-derived mesenchymal stem cells (UC-MSCs), and skeletal myoblasts (SMs). Since UC-MSCs have few human leukocyte antigen-II and major histocompatibility complex class I molecules, and are easy to isolate and culture, UC-MSC sheets have been proposed as a candidate for clinical applications to ischemic heart disease.

Surgical Treatment of Primary Cardiac Tumor Associated with Malignant Arrhythmias.

OBJECTIVE: Pediatric primary cardiac tumor is an extremely rare disease. The tumor can extend into the conduction system and cause malignant arrhythmias. We retrospectively reviewed 6 consecutive cases of children with primary cardiac tumor that manifested as rhythm disturbance. METHODS: In our center, 6 children were enrolled from October 2009 to August 2016. Detailed operative data and follow-up information were comprehensively collected and statistically analyzed. RESULTS: The patients were ages 1 to 16 years and weighed 7.9 to 44.5 kg. Preoperative ventricular tachycardia was present in 3 patients, frequent ventricular ectopic beats in 1 patient, supraventricular tachycardia in 1 patient, and atrial flutter in 1 patient. All 6 patients underwent a complete tumor resection. The tumors were localized in the left ventricular free wall (3 patients), left ventricular outflow tract (1 patient), left atrium (1 patient), and right atrium (1 patient). One patient received 2 radiofrequency ablation procedures before tumor resection. Postoperative sick sinus syndrome occurred in 1 patient because the tumor infiltrated the sinoatrial node. Tumors from 2 patients were pathologically diagnosed as fibroma and 4 as rhabdomyoma. Reoperation of mitral valve repair was performed in 1 patient 1 year after tumor resection. The mean (± SD) follow-up time was 63.7 ± 31.4 months, and all children were well, with Ross functional classification I and no signs of recurrence or metastasis. CONCLUSIONS: In conclusion, cardiac tumor is a rare but nonneglectable reason for arrhythmia, and surgical resection is the optimal procedure, with satisfactory results.

A novel mechanical parameter to quantify the microarchitecture effect on apparent modulus of trabecular bone: A computational analysis of ineffective bone mass.

BACKGROUND: One of the characteristics of osteoporotic bone is the deterioration of trabecular microarchitecture. Previous studies have shown microarchitecture alone can vary the apparent modulus of trabecular bone significantly independent of bone volume fraction (BV/TV) from morphological and topological perspectives. However, modulus is a mechanical quantity and there is a lack of mechanical explanatory parameters. This study aims to propose a novel mechanical parameter to quantify the microarchitecture effect on the apparent modulus of trabecular bone. MATERIALS AND METHODS: Fourteen human female cadaveric vertebrae were scanned with a dual-energy X-ray (DXA) equipment followed by a micro-CT (µCT) system at 18 µm isotropic resolution. Four trabecular bone specimens (3.46 × 3.46 × 3.46 mm) were obtained from each vertebral body and converted to voxel-based micro finite element (µFE) models. The apparent modulus (E) of the µFE model was computed using a linear micro finite element analysis (µFEA). The normalized apparent modulus (E*) was computed as E divided by BV/TV. The relationship between E and BV/TV was analyzed by linear, power-law and exponential regressions. Linear regression was performed between E* and BV/TV. Ineffective bone mass (InBM) was defined as the bone mass with a negligible contribution to the load-resistance and represented by elements with von Mises stress less than a certain stress threshold. InBM was quantified as the low von Mises stress ratio (LSVMR), which is the ratio of the number of InBM elements to the total number of elements in the µFE model. An incremental search technique with coarse and fine search intervals of 10 and 1 MPa, respectively, was adopted to determine the stress threshold for calculating LSVMR of the µFE model. Correlation between E* and LSVMR was analyzed using linear and power-law models for each stress threshold. The threshold producing the highest coefficient of determination (R2) in the correlation between E* and LSVMR was taken as the optimal stress threshold for calculating LSVMR. Linear regression was performed between E and LSVMR. Multiple linear regression of E against both BV/TV and LSVMR was further analyzed. RESULTS: E significantly (p < .001) correlates to BV/TV whereas E* has no significant (p = .75) correlation with BV/TV. Incremental search suggests 59 MPa to be the optimal stress threshold for calculating LSVMR. BV/TV alone can explain 59% of the variation in E using power-law regression model (E = 2254.64BV/TV1.04, R2 = 0.59, p < .001). LSVMR alone can explain 48% of the variation in E using linear regression model (E = 1696.4-1647.1LSVMR, R2 = 0.48, p < .001). With these two predictors taken into consideration, 95% of the variation in E can be explained in a multiple linear regression model (E = 1364.89 + 2184.37BV/TV - 1605.38LSVMR, adjusted R2 = 0.95, p < .001). CONCLUSION: LSVMR can be adopted as the mechanical parameter to quantify the microarchitecture effect on the apparent modulus of trabecular bone.

The measured mechanical properties of osteoporotic trabecular bone decline with the increment of deformation volume during micro-indentation.

PURPOSE: Osteoporosis is a critical global health issue. However, the biomechanical properties of osteoporotic trabecular bone have not been well understood due to its hierarchically complex structure mingled with accumulated microcracks. Previous studies indicated the mechanical behaviors of trabecular bone may differ with varying amounts of deformation. Therefore, this study aims to further reveal the relationship between the measured mechanical properties of osteoporotic trabecular bone and various amounts of deformation volume during micro-indentation. METHODS: Two trabecular specimens were dissected transversally and frontally from an osteoporotic lumbar vertebral (L5) cadaver and embedded into Methyl methacrylate. On each specimen, two orthogonal cuts were performed to make a right-angle, followed by five parallel slicing. On each slice, the region of interest was gridded into 16 (4 × 4) sub-regions with the size equal to the microscope field. Within each sub-region, indentations were made on a single trabecula with five different indentation depths (3, 4, 5, 6, 7 µm) to induce different deformation volume. Both the indentation hardness and modulus were computed from the indenting curve for each measurement. The results of the five slices are pooled together to represent the longitudinal and circumferential mechanical characteristics, respectively. Linear regression was performed to investigate the relationship between the measured mechanical properties and various deformation volumes. RESULTS: A total of 1055 indents were made. After eliminating outliers, 840 indents were left for data analysis with 490 indents from transversal slices and 350 indents from frontal slices. Both the hardness and modulus decreased with the increasement of indentation depths. The hardness decreased by slopes of -0.65 (R2 = 0.72, p = 0.044) and -0.869 (R2 = 0.95, p = 0.003) longitudinally and circumferentially while the modulus decreased by slopes of -0.39 (R2 = 0.82, p = 0.02) and -0.348 (R2 = 0.94, p = 0.004) longitudinally and circumferentially. CONCLUSIONS: Mechanical properties of trabecular bone measured by micro-indentation can alter with the variation of deformation volume, which reflects the nonlinear behavior of vertebra from the material perspective.

Right Atrial Appendage Aneurysm Resection to Cure Aneurysm-Related Atrial Tachyarrhythmia.

Congenital right atrial appendage aneurysm (RAAA) is an extremely rare malformation that can coexist with atrial tachyarrhythmia. There is no consensus on treatment for this condition. This research aimed to investigate the clinical characteristics and efficacy of surgical resection to treat atrial tachyarrhythmia originating from RAAA in children. Four RAAA children diagnosed with atrial tachyarrhythmia at the age of 1-5.25 years weighing 8.3-17.1 kg were discussed in this retrospective study. Patients underwent various treatments, included electrocardiogram (ECG) and echocardiography, antiarrhythmic medication therapy, radiofrequency catheter ablation (RFCA), surgical resection of RAAA and pathological examinations. The results from these treatments along with clinical features of patients were analyzed. The incidence of RAAA in patients with atrial tachycardia originating from the right or left atrial appendages (RAA or LAA) was 7.3% (4/55). The prevalence of RAAA in the RAA was 12.5% (4/32). Atrial tachyarrhythmia was identified both prenatally (26 and 36 weeks of gestational age) and postnatally (1 and 4 months after birth), with two patients per group, respectively. The RAAAs condition in two patients with atrial tachycardia (AT), concomitant atrial flutter (AF) and atrial fibrillation (Af) was identified using echocardiogram. Although, RAAA in two patients with mono AT was unidentified in echocardiogram and failed to be identified in the procedure of RFCA, RAAA was confirmed during surgical resection of the RAA. Multiple pre-surgical antiarrhythmic medications combined therapy used to treat all four patients showed either no effect at all or was only partially effective. The original atrial tachyarrhythmia was successfully abolished after RAAA surgical resection in four patients. AT originating from new foci was established in two patients post-surgically. The conditions of these two patients were successfully reverted and normal sinus rhythm maintained in the application of antiarrhythmic medications. These results confirmed the efficacy of RAAA surgical resection. The pathology study showed cystic dilation in parts of the atrial cavity, fibrosis of the cyst wall, generalized fibrosis of atrial myocardium with myocardium atrophy and cystic dilation. RAAA is prone to misdiagnosis by echocardiogram. Atrial tachyarrhythmia in patients with RAAA is usually resistant to antiarrhythmic medication therapy and RFCA. Surgical resection of RAAA is a safe and effective option that is minimally invasive.

Modified Peritoneal Dialysis for Treatment of Acute Renal Failure after Complex Congenital Heart Surgery in Infants.

BACKGROUND: Acute kidney injury (AKI) is one of the common complications in infants and children after complex congenital heart surgery. Peritoneal dialysis (PD) is usually applied for renal replacement therapy (RRT), especially in infants. We investigated the efficacy and safety of modified PD for the treatment of acute renal failure and congestive heart failure after cardiac surgery for congenital heart disease in infants. METHODS: We retrospectively analyzed five consecutive patients from October 2015 to February 2017. The patients were aged from four days to five years old, and all had acute renal failure and congestive heart failure after cardiac surgery. In the five patients treated with modified PD (five males; average weight: 11.2 ± 5.5 kg), we used the Seldinger technique percutaneous abdominal puncture 16 G single lumen central venous catheter instead of the Tenckhoff peritoneal dialysis catheter as a PD catheter. Modified PD was intermittent. We recorded and monitored circulation and metabolism index. RESULTS: Five cases (100%) with modified PD were restored to normal renal function. Congestive heart failure was gradually alleviated, and pulmonary and cardiovascular function were improved. Urine volume increased. Neither peritonitis nor catheter leakage occured in any of our cases. Urine volume increased due to PD, from 0.16 + 0.18 mL/kg*h before PD to 2.63 + 1.05 ml/kg*h at the end of PD (P < .05). Serum creatinine, serum urea nitrogen, and serum K+ changed from 85.0 ± 36.5 µmol/L, 17.1 ± 7.5 mmol/L, and 4.57 ± 0.30 mmol/L before PD, to 76.0 ± 36.7 µmol/L, 20.1 ± 11.0 mmol/L, and 4.42 ± 0.42 mmol/L at the end of PD, respectively (P > .05). Acidosis, hyperkalemia, hypoxemia and low cardiac output syndrome were improved. All patients were cured and discharged with normal renal function. CONCLUSION: We conclude that modified single lumen central venous catheter for PD is a safe, feasible, and less invasive therapeutic strategy for AKI in infants undergoing cardiac surgery, and is worthy of being widely applied in clinical practice.

Successful resection of giant right atrial appendage aneurysm to cure chaotic atrial tachycardia in a child: case report.

Right atrial appendage aneurysm is an extremely rare congenital malformation with unknown aetiology. The most common potential complication is atrial arrhythmias including atrial flutter, atrial fibrillation, and atrial tachycardia. These arrhythmias are usually refractory to medication therapy. Radiofrequency catheter ablation has poor efficacy with low success rate and high recurrence rate. Aneurysm resection is the recommended treatment with satisfactory efficacy. We report a child with chaotic atrial tachycardia due to giant right atrial appendage aneurysm who was successfully treated by aneurysm resection.

Surgical Treatment for Double Outlet Right Ventricle With Pulmonary Outflow Tract Obstruction.

BACKGROUND: Double outlet right ventricle (DORV) is a conotruncal anomaly that is a defining element of many types of complex congenital heart disease. Because of a big variety of pathology, there are still some controversies with respect to the definition, classification, and surgical treatment. We report our experience with surgical treatment for DORV (as defined by the "90% rule") with pulmonary outflow tract obstruction (POTO). METHODS: From July 2005 to July 2015, 90 patients underwent surgical treatment of DORV with POTO at the First Hospital of Tsinghua University. There were 55 males and 35 females whose age varies from 3 months to 36 years (mean age 7.1 ± 9.0 years old), and body weights ranged from 5 to 63 kg (mean weight 20.4 ± 16.6 kg). Besides DORV, ventricular septal defect, and POTO, this group of patients includes some with additional associated cardiac abnormalities. RESULTS: Fourteen patients (15.6%) died. The main cause of death was low cardiac output syndrome. CONCLUSIONS: The DORV is usually associated with a variety of cardiac abnormalities and POTO is a common defining feature. Acceptable surgical results can be achieved by individualized surgical treatment of most patients. Some patients may require reoperation, and a close follow-up is needed.