Clinical Effects of Surgical Left Atrial Reduction and Concomitant Mitral Valve Replacement in Patients with Giant Left Atrium.

INTRODUCTION: A giant left atrium may cause respiratory dysfunction and hemodynamic disturbance postoperatively. This retrospective study aimed to evaluate clinical effects of surgical left atrial reduction in concomitant cardiac valves operations. METHODS: One hundred and thirty-five patients with heart valve diseases and giant left atriums from January 2004 to July 2021 were enrolled into this research. They were divided into the folded group (n=63) and the unfolded group (n=72). Patients in the folded group had undergone cardiac valve operations concomitantly with left atrial reductions. The perioperative characteristics were compared between both groups, and subgroup analysis was performed. RESULTS: There were five deaths in the folded group and 25 deaths in the unfolded group (P<0.001). Complications including pneumonia, sepsis, multiple organs dysfunction syndrome, low cardiac output syndrome, and the use of continuous renal replacement therapy were significantly fewer in the folded group. The receiver operating characteristic curve of left atrial max. diameter predicting mortality was significant (area under the curve=0.878, P=0.005), and the cutoff point was 96.5 mm. The stratified analysis for sex showed that more female patients died in the unfolded group. Logistic regression for mortality showed that the left atrium unfolded, left atrial max. diameter, cardiopulmonary bypass time, and mechanical ventilation time increased the risk of death. CONCLUSION: Surgical left atrial reduction concomitantly with valves replacement could decrease mortality and was safe and effective in giant left atrium patients.

Comparative cardioprotective effects of carvedilol versus atenolol in a rat model of cardiorenal syndrome type 4.

The incidence of chronic kidney disease is escalating; cardiorenal syndrome (CRS) type 4 is gaining a major health concern causing significant morbidity and mortality, putting major burdens on the healthcare system. This study was designed to compare the cardioprotective effects of carvedilol versus atenolol against CRS type 4 induced by subtotal 5/6 nephrectomy in rats and to explore the underlying mechanisms. Immediately after surgery, carvedilol (20 mg/kg/day) or atenolol (20 mg/kg/day) was added to drinking water for 10 weeks. Carvedilol was more effective than atenolol in improving kidney functions, decreasing elevated blood pressures, attenuating cardiac hypertrophy, reducing serum brain natriuretic peptide, and diminished cardiac fibrous tissue deposition. However, carvedilol was equivalent to atenolol in modulating ß1-adrenergic receptors (ß1ARs) and cardiac diacylglycerol (DAG) signaling, but carvedilol was superior in modulating ß-arrestin2, phosphatidyl inositol 4,5 bisphosphates (PIP2), and caspase 3 levels. Carvedilol has superior cardioprotective effects than atenolol in a rat model of CRS type 4. These protective effects are mediated through modulating cardiac ß1ARs/ß-arrestin2/PIP2/DAG as well as abating cardiac apoptotic signaling pathways (caspase3/pS473 protein kinase B (Akt)).

Reversible pulmonary trunk banding: Myocardial vascular endothelial growth factor expression in young goats submitted to ventricular retraining.

BACKGROUND: Ventricle retraining has been extensively studied by our laboratory. Previous studies have demonstrated that intermittent overload causes a more efficient ventricular hypertrophy. The adaptive mechanisms involved in the ventricle retraining are not completely established. This study assessed vascular endothelial growth factor (VEGF) expression in the ventricles of goats submitted to systolic overload. METHODS: Twenty-one young goats were divided into 3 groups (7 animals each): control, 96-hour continuous systolic overload, and intermittent systolic overload (four 12-hour periods of systolic overload paired with 12-hour resting period). During the 96-hour protocol, systolic overload was adjusted to achieve a right ventricular (RV) / aortic pressure ratio of 0.7. Hemodynamic evaluations were performed daily before and after systolic overload. Echocardiograms were obtained preoperatively and at protocol end to measure cardiac masses thickness. At study end, the animals were killed for morphologic evaluation and immunohistochemical assessment of VEGF expression. RESULTS: RV-trained groups developed hypertrophy of RV and septal masses, confirmed by increased weight and thickness, as expected. In the study groups, there was a small but significantly increased water content of the RV and septum compared with those in the control group (p<0.002). VEGF expression in the RV myocardium was greater in the intermittent group (2.89% ± 0.41%) than in the continuous (1.80% ± 0.19%) and control (1.43% ± 0.18%) groups (p<0.023). CONCLUSIONS: Intermittent systolic overload promotes greater upregulation of VEGF expression in the subpulmonary ventricle, an adaptation that provides a mechanism for increased myocardial perfusion during the rapid myocardial hypertrophy of young goats.

149 Fontan Conversions.

Patients with a functionally univentricular heart who have had an atriopulmonary Fontan are at risk for atrial dilatation, atrial arrhythmias, and progressive circulatory failure. Between 1994 and 2018, we performed 149 Fontan conversions with arrhythmia surgery and epicardial pacemaker placement at Ann & Robert H. Lurie Children's Hospital of Chicago. This operation converts the atriopulmonary Fontan to an extracardiac Fontan that improves hemodynamics and controls the atrial arrhythmias. Operative mortality during that time was 2%, and freedom from death or heart transplant at 10 years is 84%. For properly selected patients, Fontan conversion improves both survival and quality of life. Patients with an atriopulmonary Fontan constitute an eroding population, as they face many comorbidities and have a decreased life expectancy without treatment; therefore, all patients with an atriopulmonary Fontan should be evaluated for this procedure.

Analysis of fibrosis in control or pressure overloaded rat hearts after mechanical unloading by heterotopic heart transplantation.

Mechanical unloading (MU) by implantation of left ventricular assist devices (LVAD) has become clinical routine. This procedure has been shown to reverse cardiac pathological remodeling, with the underlying molecular mechanisms incompletely understood. Most studies thus far were performed in non-standardized human specimens or MU of healthy animal hearts. Our study investigates cardiac remodeling processes in sham-operated healthy rat hearts and in hearts subjected to standardized pathological pressure overload by transverse aortic constriction (TAC) prior to MU by heterotopic heart transplantation (hHTx/MU). Rats underwent sham or TAC surgery. Disease progression was monitored by echocardiography prior to MU by hHTx/MU. Hearts after TAC or TAC combined with hHTx/MU were removed and analyzed by histology, western immunoblot and gene expression analysis. TAC surgery resulted in cardiac hypertrophy and impaired cardiac function. TAC hearts revealed significantly increased cardiac myocyte diameter and mild fibrosis. Expression of hypertrophy associated genes after TAC was higher compared to hearts after hHTx/MU. While cardiac myocyte cell diameter regressed to the level of sham-operated controls in all hearts subjected to hHTx/MU, fibrotic remodeling was significantly exacerbated. Transcription of pro-fibrotic and apoptosis-related genes was markedly augmented in all hearts after hHTx/MU. Sarcomeric proteins involved in excitation-contraction coupling displayed significantly lower phosphorylation levels after TAC and significantly reduced total protein levels after hHTx/MU. Development of myocardial fibrosis, cardiac myocyte atrophy and loss of sarcomeric proteins was observed in all hearts that underwent hHTX/MU regardless of the disease state. These results may help to explain the clinical experience with low rates of LVAD removal due to lack of myocardial recovery.

Giant Left Atrium in a 14-Month-Old Child With Compression of Airways.

Giant left atrium (GLA) is a rare entity in the pediatric population. GLA carries a significant mortality risk; once its existence is established, it needs to be evaluated with intention to treat. We report a 14-month-old boy with GLA presenting with symptoms of cough and stridor because of compressed airways. The child underwent successful surgical resection for the same.

Cardiac autotransplantation and ex vivo surgical repair of giant left atrium: a case presentation.

BACKGROUND: Chronic Mitral Valve disease is strongly associated with Left atrial enlargement; the condition has a high mortality risk. Clinical manifestations include atrial fibrillation, pulmonary hypertension, thromboembolic events, and in cases of Giant Left Atrium (GLA) and a distorted cardiac silhouette. Full sternotomy, conventional open-heart surgery, reductive atrioplasty and atrioventricular valve repair are required to resolve symptoms. However, these procedures can be complicated due to the posterior location of the GLA and concomitant right lateral protrusion. Cardiac autotransplantation is superior under these conditions; it provides improved visual access to the posterior atrial wall and mitral valve, hence, facilitates corrective surgical procedures. We aimed to assess the clinical outcome of patients undergoing cardiac autotransplantation as the primary treatment modality to resolve GLA. Moreover, we evaluated the procedural safety profile and technical feasibility. CASE PRESENTATION: Four patients, mean EuroSCORE II of 23.7% ± 7.7%, presented with heart failure, atrial fibrillation, left atrial diameter > 6.5 cm and a severe distorted cardiac silhouette; X-ray showed prominent right lateral protrusion. We performed cardiac autotransplantation using continuous retrograde perfusion with warm blood supplemented with glucose followed by atrioplasty, atrial plication, valve annuloplasty and valve repair on the explanted beating heart. The surgical approach reduced the left atrial area, mean reduction was - 90.71 cm2 [CI95% -153.3 cm2 to - 28.8 cm2, p = 0.02], and normalized pulmonary arterial pressure, mean decrease - 11.25 mmHg [CI95% -15.23 mmHg to - 7.272 mmHg, p = 0.003]. 3 out of 4 patients experienced an uneventful postoperative course; 2 out of 4 patients experienced a transient return to sinus rhythm following surgery. One was operated on in 2017 and is still in good condition; two other patients survived for more than 10 years; Kaplan-Meier determined median survival is 10.5 years. CONCLUSIONS: Cardiac autotransplantation is an elegant surgical procedure that facilitates the surgical remodelling of Giant Left Atrium. Surgical repair on the ex vivo beating heart, under continuous warm blood perfusion, is a safe procedure applicable also to high-risk patients.

A Modified Atrial Volume Reduction Technique for a Giant Left Atrium.

We describe a modified volume reduction technique for a giant left atrium that consists of circumferential resection of a strip of left atrial wall with the appendage, plicated pericardium replacing the posterior atrial wall, and anastomoses of the remaining right side free wall to the interatrial septum instead of the interatrial groove. Our initial application showed that this technique can safely reduce a giant left atrium to the desired volume and obtain a high rate of sinus rhythm restoration after a maze operation.

Is mesocardia with left-sided caval vein draining to coronary sinus a contraindication for a percutaneous pulmonary valve implantation? A case description.

Introduction Although the right jugular vein approach for percutaneous pulmonary valve implantation is well described, there are no reports that describe a percutaneous pulmonary valve implantation through a left superior caval vein to coronary sinus pathway. Case A 14-year-old female with tetralogy of Fallot, mesocardia, left superior caval vein draining into the coronary sinus, and hemiazygos continuation of the inferior caval vein underwent ventricular septal defect closure, with homograft insertion from the right ventricle to the pulmonary artery, patch augmentation of the left pulmonary artery, and creation of an atrial communication. Thereafter followed numerous catheterisations and interventions with stent implantation for stenosis of the left pulmonary artery and the homograft, as did device closure of the atrial communication. When she was a 12-year-old, the indications for a percutaneous pulmonary valve implantation were fulfilled and she underwent implantation of a 22 mm Melody® valve through the left superior caval vein. The extra-stiff exchange wire was pre-formed into a "U-spiral"-type configuration, according to the underlying anatomy, in order to provide a smooth route for the delivery of stents, to create the landing zone, and for the implantation of the Melody "ensemble". The procedure was performed under deep sedation according to our standard protocol. The duration of the procedure was 172 min and the radiation time was 24.9 min. CONCLUSION: On the basis of this unique experience, percutaneous pulmonary valve implantation is safe and feasible even in patients with unusual anatomy. Crucial is the "U-spiral" shaped configuration of the guide wire.

[Changes in the diameter and length of hypertrophic cardiomyocytes in the dilated left ventricle of cardiac surgical patients]. / Izmenenie diametra i dliny gipertrofirovannykh kardiomiotsitov dilatirovannogo levogo zheludochka u kardiokhirurgicheskikh bol'nykh.

AIM: to investigate changes in the diameter and length of hypertrophic cardiomyocytes (CMCs) in the dilated left ventricle (LV). SUBJECTS AND METHODS: Light microscopy, morphometry, and statistical analysis were used to investigate the status of the contractile apparatus and changes in the length, diameter of CHC and diameter of CMC nuclei, by using intraoperative dilated LV biopsy samples from 31 patients with valvular disorders and dilated cardiomyopathy. Morphological findings were compared with the clinical parameters of the patients. RESULTS: CMCs in the patients with the dilated LV were hypertrophic and were at different stages of restructuring with progressive myofibrillar loss (PML). In 81% of patients, the diameter of CMCs was not significantly changed as their zones of PML extended. The length of CMCs, which correlated with the enlarged LV cavity, was increased in 52% of patients during cell restructuring with PML. In 42% of patients, the CMC nuclear diameter increased during restructuring with PML, which appeared to be associated with CMC polyploidization; in some of these patients (19% of the total number of patients), the diameter of CMCs increased in parallel with the higher diameter of their nuclei. CONCLUSION: The findings suggest that after completion of their transverse growth, hypertrophic CMCs are involved in a restructuring process with PML. The findings are consistent with the hypothesis that dilatation of the hypertrophied LV cavity is related to the preferential elongation of CMCs with an inadequate increase in their diameter. The results of the investigation may assume that the higher CMC diameter that brings to completion before the entry of the cells into the restructuring process with PML, resumes in the cells, the ploidy of which increases in the course of restructuring with PML, triggering an additional mechanism for raising the CMC diameter at this stage of myocardial hypertrophy. The results are indicative of different mechanisms for increasing the diameter and length of hypertrophic CMCs, since the diameter of CMCs directly correlates with that of their nuclei, and the length increases as the zones of PML extend in the CMCs.

Preservation of Myocardial Perfusion and Function by Keeping Hypertrophied Heart Empty and Beating for Valve Surgery: An In Vivo MR Study of Pig Hearts.

Objectives. Normothermic hyperkalemic cardioplegia arrest (NHCA) may not effectively preserve hypertrophied myocardium during open-heart surgery. Normothermic normokalemic beating perfusion (NNBP), keeping hearts empty-beating, was utilized as an alternative to evaluate its cardioprotective role. Materials and Methods. Twelve hypertrophied pig hearts at 58.6 ± 7.2 days after ascending aorta banding underwent NNBP and NHCA, respectively. Near infrared myocardial perfusion imaging with indocyanine green (ICG) was conducted to assess myocardial perfusion. Left ventricular (LV) contractile function was assessed by cine MRI. TUNEL staining and western blotting for caspase-3 cleavage and cardiac troponin I (cTnI) degradation were conducted in LV tissue samples. Results. Ascending aortic diameter was reduced by 52.7% ± 0.4% at approximately fifty-eight days after banding. LV wall thickness was significantly higher in aorta banding than in sham operation. Myocardial blood flow reflected by maximum ICG absorbance value was markedly higher in NNBP than in NHCA. The amount of apoptotic cardiomyocyte was significantly lower in NNBP than in NHCA. NNBP alleviated caspase-3 cleavage and cTnI degradation associated with NHCA. NNBP displayed a substantially increased postoperative ejection fraction relative to NHCA. Conclusions. NNBP was better than NHCA in enhancing myocardial perfusion, inhibiting cardiomyocyte apoptosis, and preserving LV contractile function for hypertrophied hearts.

Right-Dominant Unbalanced Atrioventricular Septal Defect: Echocardiography in Surgical Decision Making.

BACKGROUND: Management of right-dominant atrioventricular septal defect (AVSD) remains a challenge given the spectrum of ventricular hypoplasia. The purpose of this study was to assess whether reported echocardiographic indices and additional measurements were associated with operative strategy in right-dominant AVSD. METHODS: A blinded observer retrospectively reviewed preoperative echocardiograms of patients who underwent surgery for right-dominant AVSD (January 2000 to July 2013). Ventricular dimensions, atrioventricular valve index (AVVI; left valve area/right valve area), and right ventricular (RV)/left ventricular (RV/LV) inflow angle were measured. A second observer measured a subset of studies to assess agreement. Pearson correlation analysis was performed to examine the relationship between ventricular septal defect size (indexed to body surface area) and RV/LV inflow angle in systole. A separate validation cohort was identified using the same methodology (August 2013 to July 2016). RESULTS: Of 46 patients with right-dominant AVSD (median age, 1 day; range, 0-11 months), overall survival was 76% at 7 years. Twenty-eight patients (61%) underwent single-ventricle palliation and had smaller LV dimensions and volumes, AVVIs (P = .005), and RV/LV inflow angles in systole (P = .007) compared with those who underwent biventricular operations. Three patients undergoing biventricular operations underwent transplantation or died and had lower indexed LV end-diastolic volumes compared with the remaining patients (P = .005). Interobserver agreement for the measured echocardiographic indices was good (intraclass correlation coefficient = 0.70-0.95). Ventricular septal defect size and RV/LV inflow angle in systole had a strong negative correlation (r = -0.7, P < .001). In the validation cohort (n = 12), RV/LV inflow angle in systole ≤ 114° yielded sensitivity of 100% and AVVI ≤ 0.70 yielded sensitivity of 88% for single-ventricle palliation. CONCLUSIONS: Mortality remains high among patients with right-dominant AVSD. RV/LV inflow angle in systole and AVVI are reproducible measurements that may be used in conjunction with several echocardiographic parameters to support suitability for a biventricular operation in right-dominant AVSD.

Cardiac Magnetic Resonance Imaging Predictors of Short-Term Outcomes after High Risk Coronary Surgery.

BACKGROUND: The euroSCORE II is a widely used pre-coronary artery bypass graft surgery (CAGS) risk score, but its predictive power lacks the specificity to predict outcomes in high-risk patients (16) and left ventricular (LV) dysfunction (<40%) based on 2D-echocardiography who underwent CAGS and in whom CMRI (1.5T) was performed preoperatively were retrospectively studied. Cardiac magnetic resonance imaging parameters were assessed in patients who either had complications immediately post-surgery (n=35), six weeks post-surgery (n=20) or were uncomplicated. RESULTS: The average age of patients recruited was 69±5 years with high euroSCORE II (22±4) and low 2D-echocardiography LV ejection fraction (38%±2%). Cardiac magnetic resonance imaging results demonstrated that those with immediate complications had higher LV scar/infarct burden as a proportion of LV mass (17±3% vs 10±3%; p=0.04) with lower circumferential relaxation index (2.5±0.46 vs 2.8±0.56; p=0.05) compared to those with no complications. Early mortality from surgery was 17% (n=9) and was associated with lower RV stroke volume (55±12 vs 68±18; p=0.03) and higher LV infarct scar/burden (18±2% vs 10±2%, p=0.04). Cardiac magnetic resonance imaging showed patients with complications at six weeks post-surgery had higher LV scar/infarct burden (14.5±2% vs 6.8±2%, p=0.03) compared to those without complications. CONCLUSION: Cardiac magnetic resonance imaging preoperative LV and RV parameters are valuable in assessing the likelihood of successful outcomes from CAGS in high-risk patients with LV dysfunction.

HDAC inhibition attenuates cardiac hypertrophy by acetylation and deacetylation of target genes.

Pharmacological histone deacetylase (HDAC) inhibitors attenuate pathological cardiac remodeling and hypertrophic gene expression; yet, the direct histone targets remain poorly characterized. Since the inhibition of HDAC activity is associated with suppressing hypertrophy, we hypothesized histone acetylation would target genes implicated in cardiac remodeling. Trichostatin A (TSA) regulates cardiac gene expression and attenuates transverse aortic constriction (TAC) induced hypertrophy. We used chromatin immunoprecipitation (ChIP) coupled with massive parallel sequencing (ChIP-seq) to map, for the first time, genome-wide histone acetylation changes in a preclinical model of pathological cardiac hypertrophy and attenuation of pathogenesis with TSA. Pressure overload-induced cardiac hypertrophy was associated with histone acetylation of genes implicated in cardiac contraction, collagen deposition, inflammation, and extracellular matrix identified by ChIP-seq. Gene set enrichment analysis identified NF-kappa B (NF-κB) transcription factor activation with load induced hypertrophy. Increased histone acetylation was observed on the promoters of NFκB target genes (Icam1, Vcam1, Il21r, Il6ra, Ticam2, Cxcl10) consistent with gene activation in the hypertrophied heart. Surprisingly, TSA attenuated pressure overload-induced cardiac hypertrophy and the suppression of NFκB target genes by broad histone deacetylation. Our results suggest a mechanism for cardioprotection subject to histone deacetylation as a previously unknown target, implicating the importance of inflammation by pharmacological HDAC inhibition. The results of this study provides a framework for HDAC inhibitor function in the heart and argues the long held views of acetylation is subject to more flexibility than previously thought.