Zen-Chung Weng

A Right-sided Aortic Arch with Kommerell's Diverticulum of the Aberrant Left Subclavian Artery Presenting with Syncope

A right-sided aortic arch with an aneurysm of the aberrant subclavian artery is a rare disease. We report a case of Kommerells diverticulum of an aberrant left subclavian artery in a patient with a right-sided aortic arch. Fewer than 50 cases have been reported in the literature. A number of operative strategies are described. Right thoracotomy provides good exposure and avoids the morbidity associated with bilateral thoracotomy or sternotomy and thoracotomy. In our patient with symptoms of dysphagia, syncope, and left subclavian steal syndrome, a left thoracotomy was used. The repair was accomplished by division of a left ligamentum arteriosum, obliteration of the Kommerells aneurysm, and an aorto-subclavian bypass. Postoperative complications included left vocal cord palsy and Horners syndrome. Hoarseness and left ptosis recovered spontaneously 3 months after surgery, and the patient remained symptom-free at the 1-year follow-up. We believe a left thoracotomy for direct repair of Kommerells diverticulum is a simple and safe method without the increased morbidity found in other procedures.

Malignancy After Heart Transplantation

Background: The purpose of this study was to assess the incidence and type of malignancies after heart transplantation at a medical institute in Taiwan. Methods: From January 1987 to December 2008, a total of 66 patients who survived more than 30 days after transplantation were enrolled in this study. Results: Of the 66 heart transplant recipients, 8 (12.1%) post‐transplant malignancies were diagnosed: 5 post‐ transplant lymphoproliferative diseases (PTLD), 1 prostate cancer, 1 lung cancer, and 1 squamous cell carcinoma of the cheek. The clinical presentations were diverse, and the diagnoses were confirmed by biopsy. Only 1 patient died of PTLD and subsequent multiple organ failure. Conclusion: Cancer is a limiting factor for long‐term survival after heart transplantation. The most common type in this study was PTLD. Early detection and aggressive treatment results in good response and preserves the allograft.

Brief Pressure Overload Preconditions Rabbit Myocardium Independent of Adenosine Receptor Activation

BACKGROUND We previously reported brief pressure overload of the left ventricle reduced myocardial infarct size. The role of adenosine receptors was investigated in this study. METHODS Pressure overload was achieved by two 10-minute partial snaring of the ascending aorta. Systolic left ventricular pressure was raised 50% above baseline value. Ischemic preconditioning was elicited by two 10-minute coronary artery occlusions. Ten minutes after different pretreatments, 60-minute occlusion of the left anterior descending coronary artery followed by 3-hour reperfusion was done to induce infarction. The area at risk and myocardial infarct size were determined by Evans blue dye injection and triphenyltetrazolium chloride staining. RESULTS Myocardial infarct size (mean ± standard deviation), expressed as percentage of area at risk, was significantly reduced in the pressure overload group (19.3 ± 2.5 %, p < 0.001) and in the ischemic preconditioning group (18.3 ± 1.8 %, p < 0.001) versus the control group (27.3 ± 3.3 %). Pretreatment with 8-(p-sulfophenyl)-theophylline, an adenosine receptor antagonist, limited the protection by ischemic preconditioning (26.8 ± 3.7%), but not that by pressure overload (19.2 ± 2.5%, p < 0.001). The 8-(p-sulfophenyl)-theophylline did not significantly affect the extent of infarct (26.4 ± 5.4%). The hemodynamics prior to treatment, area at risk, and mortality were not significantly different among all groups of animals. CONCLUSIONS Brief pressure overload of the left ventricle preconditioned rabbit myocardium against infarction. Because 8-(p-sulfophenyl)-theophylline had no significant effect on this response, the results are consistent with the hypothesis that the underlying mechanism does not depend on activation of adenosine receptors.

Cardiac Myocyte Progenitors from Adult Hearts for Myocardial Regenerative Therapy

Background: The heart is a highly vascular organ and prolonged interruption of myocardial blood flow initiates events that culminate in cardiac myocyte death. Proposed experimental reparative strategies include harvesting potent cells followed by direct injection into ischemic myocardium to achieve myogenesis and angiogenesis. Methods: Accordingly, we set out to isolate and expand a purified population of adult rat putative cardiomyocyte precursors, and to identify their characteristics in vitro. By using an acute myocardial infarction model and direct cell implantation, we further tested the hypothesis that these cells are an ideal cell source for myocardial regeneration and can enhance cardiac repair after implantation into the ischemic rat heart. Results: We describe here the identification of a subpopulation of primitive cells from rat heart, processing stem cell marker, c‐kit and myogenic transcriptional factors, GATA‐4 and MEF 2C, and cardiac specific proteins, troponin‐I, a‐sarcomeric actinin and connexin‐43. They exhibited a high in vitro proliferative potential. These findings strongly suggest that these cells are putative cardiomyocyte precursors. After transplantation, they were able to be retained and proliferate (13.63 ± 5.97% after 2 weeks) within the ischemic heart. Progeny of implanted cells migrated along the infarcted scar, reconstituted regenerated cardiomyocytes with incorporation into host myocardium, and inhibited cardiac remodeling with decreased scar formation. Conclusion: Our findings suggest that putative cardiomyocyte precursors isolated from adult heart could potentially be an autologous cell source for myocardial regeneration cell therapy.

Coronary Artery Bypass Grafting in Patients with Left Ventricular Dysfunction

Background: Coronary artery bypass grafting surgery (CABG) remains a challenge for patients with coronary artery disease and left ventricular (LV) dysfunction. The aim of this study was to evaluate the result of CABG in patients with LV dysfunction. Methods: Medical records of 1,847 patients who underwent primary, isolated CABG at Taipei Veterans General Hospital from January 1, 1991 to December 31, 2002, were reviewed. The mortality rate associated with clinical and operative variables was compared between patients with LV ejection fraction (LVEF) = 35% and patients with LVEF < 35%. Results: Patients with LVEF < 35% had more episodes of myocardial infarction (57.5% vs 28.9%, p < 0.001) and history of congestive heart failure (18.1% vs 3.2%, p < 0.001), higher New York Heart Association (NYHA) class, and higher angina class. Longer cardiopulmonary bypass time (147 ± 44 minutes vs 137 ± 40 minutes, p < 0 .001) but fewer left internal mammary artery (LIMA) grafts (46.8% vs 65.7%, p < 0.001) were used in patients with LVEF < 35%. Patients with LVEF < 35% had significantly higher hospital mortality (6.6% vs 2.2%, p < 0.001), higher major morbidity (23.3% vs 16.1%, p < 0.01), and longer hospital stay (25 ± 23 days vs 21 ± 16 days, p < 0.01). Conclusion: Although patients with LV dysfunction had higher mortality and morbidity, CABG could be done in these high‐risk patients with acceptable results.

Prenatal Diagnosis of Tetralogy of Fallot with Pulmonary Atresia

Tetralogy of Fallot involves an abnormal embryological development in which an unequal conotruncal division results in a small pulmonary artery and a great aortic artery. In its most severe form, the infundibulum of the right ventricle and the pulmonary artery can be atretic with the anomaly commonly referred to as pulmonary atresia with ventricular septal defect. Reported here is a case of prenatal diagnosis of tetralogy of Fallot with pulmonary atresia. The characteristic ultrasonographic findings included a small pulmonary artery, a large aorta, and a ventricular septal defect. The search for an atretic pulmonary valve and a ductus arteriosus with reversed blood flow was emphasized in the presence of asymmetrically dilated fetal heart. After birth, the newborn received single-stage total correction for the tetralogy of Fallot and was discharged a month later in stable condition. In this case report, the neonatal angiogram is added for confirming the prenatal diagnosis, which is of value in teaching fetal echocardiography to novice practitioners. We believe a prenatal diagnosis of tetralogy of Fallot can improve neonatal outcome.

Prenatal Diagnosis of Dextrotransposition of the Great Arteries

Dextrotransposition of the great arteries (DTGA) is a common cardiac cause of cyanosis in newborn infants that can cause acidosis and death within a short period of time unless there is a large atrial-level shunt or a patent ductus arteriosus. Here, we report a case of prenatal diagnosis of DTGA at 24+1 gestational weeks. In a tilted 4-chamber view, the pulmonary trunk branched to the left and the right pulmonary, with its root connected to the left ventricle outflow tract. In the short-axis view, the pulmonary trunk was shown to be parallel with the ascending aortic root. Cesarean section was performed due to the nonreassuring fetal status at 38+5 gestational weeks. The male neonate appeared to have mild cyanotic symptoms and weighed 3,108 g. Apgar scores were 8 and 9 at 1 and 5 minutes, respectively. Neonatal echocardiography was performed immediately after birth and the findings confirmed DTGA associated with atrial septal defect secundum. Postnatally, angiography confirmed the echocardiographic diagnosis of DTGA with a large atrial septal defect secundum and a large patent ductus arteriosus. Jatene arterial switch operation and atrial septal defect closure with Gore-Tex patch were performed. The neonate withstood the operation well and was discharged 27 days after birth weighing 2,950 g and in a stable condition. Prenatal diagnosis of DTGA can greatly aid to prepare the patients family and the surgeon and significantly improve the outcome of complex heart disease in the neonatal period.

Primary cardiac fibroma in an infant: Computed tomography and magnetic resonance imaging findings

Cardiac fibromas (CFs) are benign primary tumors that typically occur during childhood and may be asymptomatic. However, due to the proximity of CFs to the cardiac structure, significant morbidity and mortality may also be anticipated. CFs do not show spontaneous regression and surgical resection generally remains the treatment of choice for these tumors in children. Thus, it is important to take aggressive steps to obtain accurate pretreatment image diagnosis. A full-term male infant was presented to our facility suffering from shortness of breath, after an episode of upper respiratory tract infection at age 1.5 months. Subsequent chest X-ray revealed widening of the mediastinum and trachea deviation. Cardiogenic pathology was suspected. Computed tomography and magnetic resonance imaging were performed, and we confirmed a diagnosis of benign CF. Thoracotomy biopsy of the tumor confirmed the pathological diagnosis.