Detection of pathogens from venous or arterial blood of patients with left-sided infective endocarditis by metagenomic next-generation sequencing: A prospective study.

BACKGROUND: Infective endocarditis is a life-threatening uncommon infectious disease, and we aimed to explore the clinical utility of venous or arterial blood-based metagenomic next-generation sequencing (mNGS) approaches to diagnose left-sided infective endocarditis (LSIE). METHODS: We prospectively studied 79 LSIE patients who received valvular surgery in our hospital. Results of blood culture, valve culture, venous blood-based mNGS, arterial blood-based mNGS, venous blood-based mNGS plus blood culture, and arterial blood-based mNGS plus blood culture were evaluated and compared. RESULTS: Both venous blood- and arterial blood-based mNGS methods displayed significantly higher positive detection rates than blood culture and valve culture (43.0 %, 49.4 % vs. 32.9 %, 19.0 %; P < 0.001). Strikingly, when combining blood-based mNGS and blood culture, the positive rate could be further improved to more than 60 %. Moreover, we found mNGS LSIE detection was closely associated with preoperative leukocyte (P = 0.027), neutrophil value (P = 0.018), vegetation ≥ 14 mm (P = 0.043), and vegetations in aortic valve (P = 0.048). In addition, we discovered that blood-based mNGS had a superir capacity over blood culture to detect gram-negative bacteria, fungi, Bartonella Quintana, and mixed infections than blood culture. CONCLUSION: This study indicates that venous blood- and arterial blood-based mNGS displayed high positive rate in the rapid detection of pathogens in high-risk LSIE patients.

ASSESS-IE: a Novel Risk Score for Patients with Infective Endocarditis.

Mortality in patients with infective endocarditis (IE) remains high. The existing risk scores are relatively complex with limited clinical application. This study was conducted to establish a new risk model to predict in-hospital and 6-month mortality in IE patients. A total of 1549 adult patients with definite IE admitted to Guangdong Provincial People's Hospital (n=1354) or Xiamen Cardiovascular Hospital (n=195) were included. The derivation cohort consisted of 1141 patients. The score was developed using the multivariate stepwise logistic regression analysis for in-hospital death. Bootstrap analysis was used for validation. Discrimination and calibration were evaluated by the receiver operating characteristic curve and the Hosmer-Lemeshow goodness-of-fit test. Six risk factors were used as score parameters (1 point for each): aortic valve affected, previous valve replacement surgery, severe heart failure, elevated serum direct bilirubin, moderate-severe anemia and acute stage. The predictive value and calibration of the ASSESS-IE score for in-hospital death were excellent in the derivation (area under the curve [AUC]=0.781, p<0.001; Hosmer-Lemeshow p=0.948) and validation (AUC=0.779, p<0.001; Hosmer-Lemeshow p=0.520) cohorts. The score remained excellent in bootstrap validation (AUC=0.783). The discriminatory ability of the ASSESS-IE score for in-hospital (AUC: 0.781 vs. 0.799, p=0.398) and 6-month mortality (AUC: 0.778 vs. 0.814, p=0.040) were similar with that of Park's score which comprised 14 variables. The ASSESS-IE risk score is a new and robust risk-stratified tool for patients with IE, which might further facilitate clinical decision-making.

Coxiella burnetii and Bartonella Endocarditis Diagnosed by Metagenomic Next-Generation Sequencing.

(1) Background: Culture-negative endocarditis is challenging to diagnose. Here, we retrospectively identified 23 cases of Coxiella burnetii and Bartonella endocarditis by metagenomic next-generation sequencing. (2) Methods: Twenty-three patients with culture-negative endocarditis were retrospectively enrolled from Guangdong Provincial People's Hospital (n = 23) between April 2019 and December 2021. Metagenomic next-generation sequencing was performed on blood (n = 22) and excised cardiac valvular tissue samples (n = 22) for etiological identification, and Sanger sequencing was performed for pathogenic diagnostic verification. The demographic and clinical data of the 23 patients were obtained from hospital electronic health records. (3) Results: A total of 23 male patients (median age, 56 years (interquartile range, 16)) with culture-negative endocarditis were diagnosed with Coxiella burnetii (n = 21) or Bartonella (n = 2) species infection by metagenomic next-generation sequencing. All patients underwent cardiac surgery. The resected tissue exhibited both a significantly higher number of unique suspected pathogen read-pairs and more unique pathogen read-pairs than the blood specimens. The results of Sanger sequencing tests on all remaining tissue and blood specimens were positive. Oral doxycycline was added to the antibiotic regimen for at least 1.5 years according to etiology. A total of 21 patients (91%) were discharged, and 20 patients were healthy at the 21-month (interquartile range, 15) follow-up visit. One patient exhibited endocarditis relapse with the same pathogen from inadequate antibiotic administration. The last 2 patients (9%) developed septic shock and multiple organ dysfunction syndrome postoperatively and died shortly after discharge. (4) Conclusions: CNE caused by C. burnetii and Bartonella species is challenging to diagnose and exhibits poor outcome due to delayed treatment. In response, mNGS, characterized by high sensitivity and rapid results, is an effective alternative for the etiological identification of C. burnetii and Bartonella endocarditis.

Application of Metagenomic Next-Generation Sequencing in the Etiological Diagnosis of Infective Endocarditis During the Perioperative Period of Cardiac Surgery: A Prospective Cohort Study.

Objective: The present study aimed to prospectively evaluate the role of metagenomic next-generation sequencing (mNGS) in the etiological diagnosis of patients with perioperative infective endocarditis (IE). Methods: From May 1st, 2019 to December 31st, 2020, a total of 99 patients with IE were enrolled in the present study according to the modified Duke criteria, etiological, and pathological results. 11 non-IE patients undergoing heart valve surgery in the same period were selected as the control group. A blood culture test was performed immediately after admission, and the valves harvested operatively were examined by blood culture and mNGS. Results: In the IE group, there were 29 cases (29.3%) with positive blood culture, 16 cases (16.2%) with positive valve culture, and 85 cases (85.9%) with positive valve mNGS. Compared to culture-based detection, mNGS achieved better performance with a sensitivity, specificity, area under the curve (AUC) of 0.859, 0.727, and 0.793, respectively. The combined approach using culture and mNGS further improved the diagnostic accuracy (sensitivity 89.9%, specificity 72.7%, AUC 0.813). Preoperative white blood cell (P = 0.029) and neutrophils (P = 0.046) were identified as independent factors affecting the detection rate of mNGS. In the mNGS-positive group, 95 strains of pathogens were found and 10 cases were identified with mixed infection. There were 72 gram-positive bacteria and 14 gram-negative bacteria. mNGS positive group displayed higher species richness than mNGS negative group with enrichment of Streptococcus sanguis, Streptococcus buccalis, and Streptococcus griseus. Proteobacteria and Actinomycetes were enriched in mNGS negative group. Notably, six patients showed disconcordant results between culture and mNGS. Rothia aeria was identified in the blood culture, valve culture, and valve mNGS in one patient. Bartonella Quintana and Coxiella burnetii, which were fastidious intracellular bacteria, were found in two blood and valve culture-negative cases. Conclusions: mNGS outperformed the conventional culture method and displayed high accuracy in detecting pathogens in IE patients. This study provided support for the use of mNGS in the etiological diagnosis of IE.

The Efficacy of Resin Hemoperfusion Cartridge on Inflammatory Responses during Adult Cardiopulmonary Bypass.

AIM: This study aimed to evaluate the efficacy of the resin hemoperfusion device (HA380 hemoperfusion cartridge) on inflammatory responses during adult cardiopulmonary bypass (CPB). METHODS: Sixty patients undergoing surgical valve replacement were randomized into the HP group (n = 30) with an HA380 hemoperfusion cartridge in the CPB circuit or the control group (n = 30) with the conventional CPB circuit. The results of routine blood tests, blood biochemical indexes, and inflammatory factors were analyzed at V0 (pre-CPB), V1 (CPB 30 min), V2 (ICU 0 h), V3 (ICU 6 h), and V4 (ICU 24 h). RESULTS: The HP group had significantly lower levels of IL-6, IL-8, and IL-10. Significant estimation of group differences in the generalized estimating equation (GEE) models was also observed in IL-6 and IL-10. The HP group had significantly lower levels of creatinine (Cr), aminotransferase (AST), and total bilirubin (TBil) compared to the control group. The estimation of differences of Cr, AST, and TBil all reached statistical significance in GEE results. The HP group had significantly less vasopressor requirement and shorter mechanical ventilation time and ICU stay time as compared to the control group. CONCLUSION: The HA380 hemoperfusion cartridge could effectively reduce the systemic inflammatory responses and improve postoperative recovery of patients during adult CPB.

A Modified Technique for Valve Regurgitation After Partial Atrioventricular Septal Defect Repair.

Given its complex pathologic anatomy, recurrent left atrioventricular valve regurgitation after partial atrioventricular septal defect repair remains a challenge for surgical correction. Here, we introduce a modified bridging technique by shortening the anteroposterior leaflet distance in selected patients with inadequate coaptation to compensate for the short leaflet height, specifically that of the anterior leaflet.

T1 mapping and feature tracking imaging of left ventricular extracellular remodeling in severe aortic stenosis.

BACKGROUND: Left ventricular (LV) extracellular remodeling is a critical process in aortic stenosis (AS), which is related to functional abnormalities. Data regarding the use of combined T1 mapping and feature tracking (FT) to assess LV extracellular remodeling in severe AS are scarce. This study aimed to investigate the ability of T1-derived and FT-derived parameters to identify and assess the changes in process of LV extracellular remodeling in patients with severe AS. METHODS: A total of 49 patients with severe AS and 20 healthy volunteers were prospectively recruited. Modified look-locker inversion-recovery T1 mapping and FT imaging were performed in all participants using 3.0-T cardiac magnetic resonance imaging. The degree of myocardial fibrosis was quantified using Masson trichrome stain in biopsy specimens obtained intraoperatively from 13 patients and expressed as collagen volume fraction (CVF). Patients were divided into subgroups according to preserved LV ejection fraction (LVEF) (LVEF ≥50%) or reduced LVEF (LVEF <50%). RESULTS: Regarding the diffuse fibrosis burden, extracellular volume (ECV) was statistically insignificant between patients with preserved LVEF) and controls (28.0%±3.3% vs. 26.5%±2.3%, P>0.05). ECV in the reduced LVEF group (n=20) was significantly higher than that in the preserved LVEF group (n=29) (30.4%±3.9% vs. 28.0%±3.3%, P<0.05). Regarding the myocardial strain, global longitudinal strain (GLS) showed increasing impairment from the control group to the preserved LVEF AS group to the reduced LVEF AS group (-23.4%±3.3% vs. -18.6%±3.8% vs. -11.2%±4.8%, P<0.05). A significant correlation was found between ECV and CVF (r=0.64, P=0.020), whereas the correlation between GLS and CVF was insignificant. Significant correlations were observed between GLS and LV mass index (r=0.72, P=0.006) and LVEF (r=0.82, P<0.001). However, no correlations were found between ECV and LV mass index (P=0.172) and between ECV and LVEF (P=0.339). Discrimination of patients with preserved LVEF from controls, GLS yielded the best diagnostic performance as defined by the area of under the curve (-0.83), and GLS, ECV, and post-T1 were significant discriminators after regression analysis. CONCLUSIONS: In the process of LV extracellular remodeling in severe AS, ECV is the structural marker of extracellular fibrosis burden, and GLS is the functional marker before the fibrosis burden intensifies.

ECG-gated CT in Aortic Perivalvular Abscess: Comparison with Transesophageal Echocardiography and Intraoperative Findings.

Background The 2015 European Society of Cardiology guidelines acknowledged similar diagnostic performance of electrocardiography (ECG)-gated CT on perivalvular abscesses compared with transesophageal echocardiography (TEE), but data on ECG-gated CT remain insufficient. Purpose To determine the diagnostic performance of ECG-gated CT for assessing aortic root perivalvular abscesses and to compare it with TEE. Materials and Methods Between January 2008 and June 2019, the imaging records of surgically confirmed infective endocarditis were retrospectively reviewed for presence of aortic perivalvular abscesses, their extension, fistulization, vegetations, and valvular destruction. The diagnostic performance of ECG-gated CT was analyzed in all patients (part A) and in an noninferiority analysis (part B; δ = -10%) in patients undergoing TEE. Results A total of 178 patients (median age, 54 years [interquartile range, 15 years]; 147 men) were evaluated (CT, n = 178; TEE, n = 35). In part A, the sensitivity and specificity of CT were 70 of 71 (99% [95% confidence interval (CI): 96%, 100%]) and 102 of 107 (95% [95% CI: 91%, 99%]) for abscess; 65 of 68 (96% [95% CI: 91%, 100%]) and 107 of 110 (97% [95% CI: 94%, 100%]) for extension, 36 of 36 (100% [95% CI: 100%, 100%]) and 139 of 142 (98% [95% CI: 96%, 100%]) for fistulization, 153 of 160 (96% [95% CI: 93%, 99%]) and five of 18 (28% [95% CI: 7%, 49%]) for vegetations, and 90 of 90 (100% [95% CI: 100%, 100%]) and 24 of 88 (27% [95% CI: 18%, 37%]) for valvular destruction. In part B, ECG-gated CT had noninferior sensitivity compared with TEE for detecting abscess (difference, 14 percentage points [lower one-sided 95% CI: -4 percentage points]), extension (difference, 0 percentage points [lower one-sided 95% CI: 0 percentage points]), fistulization (difference, 0 percentage points [lower one-sided 95% CI: 0 percentage points]), and valvular destruction (difference, 5 percentage points [lower one-sided 95% CI: -4 percentage points]). Specificity of CT was inferior for demonstrating perivalvular abscess (difference, 5 percentage points [lower one-sided 95% CI: -11 percentage points]) and valvular destruction (difference, -62 percentage points [lower one-sided 95% CI: -92 percentage points]). ECG-gated CT had inferior sensitivity in detecting vegetations (difference, -6 percentage points [lower one-sided 95% CI: -14 percentage points]). Conclusion Electrocardiography-gated CT had noninferior sensitivity compared with transesophageal echocardiography for identification of aortic perivalvular abscesses, extension of these abscesses, fistulization, and valvular destruction but had inferior sensitivity in detection of vegetations. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Sakuma in this issue.

Upregulation of miR-146a-5p is associated with increased proliferation and migration of vascular smooth muscle cells in aortic dissection.

BACKGROUND: This study aimed to investigate whether miR-146a-5p was involved in the pathogenesis of thoracic aortic dissection (AD) via regulating the biological function of vascular smooth muscle cells (VSMCs). METHODS: Circulating miR-146a-5p level was measured by quantitative polymerase chain reaction (qPCR) in AD patients and healthy controls. Human dissected aortic samples were obtained from patients with thoracic AD Stanford type A undergoing surgical repair, and normal control samples were from organ donors who died from nonvascular diseases. The expression level of miR-146a-5p was detected using qPCR in each sample. The expression of SMAD4, which is involved in the TGF-ß pathway and indicated as the target gene of miR-146a-5p, was measured by qPCR and Western blot analysis at the mRNA level and protein level, respectively. Subsequently, VSMCs were transfected with miR-146a-5p mimics or inhibitors in vitro. VSMC proliferation and migration were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and Transwell assay, respectively. Flow cytometry was used to identify apoptosis. The expression of SMAD4 in VSMCs was determined using qPCR and Western blot analysis. RESULTS: Plasma level of miR-146a-5p is significantly higher in the AD group as compared with the control group. The expression of miR-146a-5p was significantly upregulated in dissected aorta compared with controls (P < 0.05). The overexpression of miR-146a-5p significantly induced VSMC proliferation and migration in vitro. CONCLUSIONS: The expression of SMAD4 was modulated by miR-146a-5p. miR-146a-5p induced VSMC proliferation and migration through targeting SMAD4 and hence might be potentially involved in the development of AD.

[Surgical correction of tetralogy of Fallot in adults over 40 years of age].

OBJECTIVE: To summarize the experience with surgical correction of tetralogy of Fallot in adults over 40 years of age. METHODS: From November 1985 to July 2008, 9 male and 11 female patients aged 41-53 years (mean 46.3±3.5 years) underwent total surgical correction for tetralogy of Fallot. Twelve patients had preoperative NYHA class III cardiac function. The common comorbidities included infective endocarditis, cerebral abscess, cerebral infarction, renal dysfunction, and tricuspid insufficiency. Surgical corrections were carried out at the anatomical or physiological level. RESULTS: Nineteen patients received right ventriculotomy to relieve right ventricular outflow obstruction and for ventricular septal defect closure, and 1 patient had Fontan operation. Two patients died after the surgery for heart failure and ventricular fibrillation. The average cardiopulmonary bypass time, aortic clamp time, and postoperative ventilation time was 142.9±36.3 min, 89.9±25.1 min, and 72.0±17.5 h, respectively. Postoperative low cardiac output syndrome occurred in 5 cases, septic shock in 1 case, secondary renal failure in 1 case, and bleeding in 2 cases. Echocardiography showed a significant postoperative reduction of the mean right ventricular outflow tract velocity from 4.29±1.36 m/s to 2.13±0.83 m/s (P<0.01); the right ventricular longitudinal dimension exhibited no significant changes postoperatively (57.1±6.7 mm vs 55.1±7.0 mm, P=0.65). CONCLUSIONS: Surgical correction of the tetralogy of Fallot in patients over 40 years is highly risky and requires appropriate management of cardiac failure, careful myocardial protection, and thorough intracardiac lesion correction to decrease surgical complications.

Surgical outcome of isolated total anomalous pulmonary venous connection in adults: a 14-year experience.

AIM OF THE STUDY: To investigate the surgical result of adult total anomalous pulmonary venous connection (TAPVC). METHODS: From March 1997 to March 2011, 12 adult cases of isolated TAPVC, with an average age of 24.9 ± 6.7 years (from 18 to 41 years), underwent surgical repair in our department. All patients suffered from right-sided volume overload with clinical manifestations varying from mild cyanosis to severe heart failure. RESULTS: According to Darling's classification, eight cases were classified as supracardiac type, four as cardiac type. Unobstructed connections were established between the left atrium and the pulmonary common vein in all patients with external cardiac approach in four supracardiac cases, and internal cardiac approach in four cardiac and three supracardiac cases, and Warden technique in one supracardiac patient. Concomitant operations included De Vega's tricuspid annuloplasty in six patients, patent arteriosus ductus closure in two. All patients survived the operation, and postoperative follow-up was 100% complete with a period ranging from 10 months to 14 years. NYHA grade decreased from 2.33 ± 0.49 to 1.08 ± 0.29 (p < 0.01). Three patients had postoperative tricuspid insufficiency. Five patients had cardiac arrhythmia, among two symptomatic cases; one controlled with medication, another received a successful radiofrequency ablation for incision-related atrial flutter. CONCLUSIONS: Surgical correction of isolated adult TAPVC can be carried out safely with acceptable long-term outcome. Postoperative tricuspid insufficiency and cardiac arrhythmias may have a negative long-term impact, which should be evaluated preoperatively and managed individually during surgery.

[Surgical treatment of congenital bicuspid aortic valve in 73 patients aged over 50 years].

OBJECTIVE: To summarize the clinical characteristics, surgical management and postoperative complications in patients with congenital bicuspid aortic valve (CBAV) over 50 years of age. METHODS: From January 2009 to September 2011, 73 CBAV patients aged 51-76 years (mean 61.8∓0.73 years) were treated in our center. Except for 1 patient who underwent Bentall surgery and another having Wheat surgery, all the patients received aortic valve replacement (AVR), including 7 with double (mitral and aortic) valve replacement (DVR), 6 with mitral valvular plasty, 11 with tricuspid valvular plasty, 8 with coronary artery bypass graft implantation, 1 with aortic-left ventricular tunnel repair, 1 with atrial maze ablation, and 1 with left atrial thrombosis removal. RESULTS: Two patients died after the surgery, with a perioperative mortality rate of 2.7%. The cardiopulmonary bypass time was 78-217 min (mean 131.9 ∓6.0 min) with an aortic blocking time of 56-158 min (mean 88.2 ∓4.8 min) and total postoperative ICU time of 23.0-647.4 h (mean 97.9∓10.5 h). The postoperative complications included low heart output syndrome in 5 cases, bleeding in 4 cases, wound debridement in 4 cases, and hemodialysis due to acute renal failure in 1 case. The left ventricular end diastolic diameter reduced significantly after the surgery (52.6∓1.7 vs 43.2∓1.0, P=0.001). No significant changes were detected in the left ventricular ejection fraction (62.3∓2.5 vs 65.5∓1.3, P=0.257). CONCLUSION: Thorough preoperative examination, preoperative risk factor assessment, timely perioperative interventions, careful evaluation of patients' tolerance of surgery, and prevention of surgical complications are essential to decrease the perioperative mortality in elderly patients with CBAV.

[Effect of decellularization on tissue composition and immunogenicity of porcine and human aortic valves].

OBJECTIVE: To study the changes of tissue composition and immunogenicity of porcine and human aortic valves after decellularization. METHODS: Three cryopreserved human aortic valves and 4 porcine valves were decellularized with trypsin, and the leaflet tissue was homogenized for SDS-PAGE protein electrophoresis and U-937 migration assay. RESULTS: Trypsin effectively removed the cells from the valve. SDS-PAGE demonstrated an obvious difference in the tissue composition between porcine and human valves. Although decellularization significantly diminished the differences between the valves, decellularized procine aortic valve stilled contained more protein components (between 26 000 and 43 000) than human valve. U-937 migration assay showed an obvious decrease of cell migration in the valves by decellularization (from 832.7×10(3) to 152.4∓31.1×10(3) for porcine valves, P<0.01, and from 644.9×10(3) to 91.2×10(3) for the human valves, P<0.01). Decellularized porcine valves induced a significantly greater cell migration than decellularized human valves (P<0.05). CONCLUSION: Decellularization with trypsin can effectively decrease the immunogenicity of human or porcine heart valve, but can not completely eliminate the antigen, and decellularized porcine valve still retain strong immunogenicity.

[Subcutaneous implantation of tissue-engineered heart valve leaflets in nude mice].

OBJECTIVE: To investigate the viability of tissue-engineered heart valve leaflets prepared with cell-polymer constructs in nude mice. METHODS: Sheep endothelial cells and smooth muscle cells/fibroblasts were seeded on patches of PHA and implanted subcutaneously in athymic mice (BALB/C). The cell-polymer constructs were harvested 12, 14, 21 and 28 days after implantation. RESULTS: Fourteen days after implantation, the cell-polymer constructs exhibited similar color with the autologous tissues, and HE staining showed more numerous cells in the implant. At 28 days following implantation, muscular fibers were formed in the cell-polymer constructs. V-G staining showed positive collagen staining in the implant at 12 days after implantation, while the control implants retrieved 28 days after implantation did not show extensive tissue formation or muscular fiber formation. CONCLUSION: The cell-polymer constructs can survive in vivo and has the potential to grow into autologous valve leaflets in the nude mice.

[Effect of trypsin and Triton-X 100 for decellularization of porcine aortic heart valves].

OBJECTIVE: To test two decellularization procedures for their potential of cell removal and mormal matrix preservation. METHODS: Porcine aortic valve leaflets were treated with either 0.05% trypsin or 0.25% Triton-X 100 respertively for 48 h for decellularization and with fresh untreated valve leaflets as control. Two tissue samples from each group were stained with hematoxylin and eosin and observed light-microscopically followed by scanning electron microscopy. Ten valve leaflets in each group were measured for shrinkage temperature, tensile strength/fracture toughnes and percentage elongation. RESULTS: Trypsin and Triton-X 100 all achieved complete decellularization but Triton-X 100 caused stronger structural alterations. No significant difference was identified between untreated and trypsin groups in shrinkage temperature, tensile strength/fracture toughnes and percentage elongation, but Triton-X 100 group showed significant difference from the other two groups. CONCLUSION: Decellularization using trypsin is superior to Triton-X100 in efficiency and matrix preservation.