Shiau-Ting Lai

Ten-year experience with surgical repair of mycotic aortic aneurysms

Background: Mycotic aneurysm remains a lethal pathologic entity, especially when rupture occurs. It may result from primary aortitis, be induced by septic emboli, or be secondary to an adjacent infection, such as pancreatitis or a psoas muscle abscess. Surgical intervention is the only way to treat such disease. Even when successful repair is achieved by insertion of an interposition in situ graft or by performance of an extra‐anatomic bypass, the prognosis is poor. The aim of this study was to present our experience of managing mycotic aortic aneurysms during the past 10 years. Methods: From January 1994 to June 2004, a total of 734 patients with aortic aneurysms underwent surgical repair at our institution. Among these cases, 17 (2.3%) were shown to be mycotic aneurysms of the ascending aorta (n = 1), aortic arch (2), thoracic and thoracoabdominal aorta (3), or abdominal aorta (11); 14 patients (mean age, 58.8 years) were male. Preoperative imaging studies were performed in all patients. Mycotic aortic aneurysms were suspected in 12 of the 17 patients (70.6%) preoperatively, and 4 of these 12 patients were found to have ruptures on imaging. At the time of surgery, 9 of the 17 aneurysms (52.9%) were ruptured. Fifteen patients had an interposition graft inserted after meticulous debridement, 1 underwent an aorto‐aortic bypass, and 1 underwent an extra‐anatomic (axillo‐femoral) bypass. An omentum patch was applied to wrap the graft in 8 of 11 mycotic aortic aneurysms of the abdominal aorta. The most common pathogens were Salmonella spp. (n = 7) and Staphylococcus spp. (4). All patients received antibiotic therapy, according to the culture report, for about 4–6 weeks postoperatively. Results: In‐hospital mortality was 11.8% (n = 2). Another patient died from massive upper gastrointestinal bleeding 6 months after operation because of complications involving an aorto‐duodenal fistula, and another died from stomach cancer 6 years after surgery. Long‐term follow‐up (mean, 37 months; range, 3–111 months) revealed that, at the time of writing, the remaining 13 patients were alive and well, without any recurrence of aneurysm. Conclusion: Mycotic aneurysm of the aorta is a life‐threatening disease, especially when rupture occurs. The high mortality rate is due not only to the high rupture rate, but also to sepsis. When mycotic aortic aneurysm is diagnosed, early surgical intervention is mandatory.

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.

Endomyocardial Biopsy-related Tricuspid Regurgitation After Orthotopic Heart Transplantation: Single-center Experience

Background: Damage of tricuspid valve (TV) with resultant tricuspid regurgitation (TR) induced by endomyocardial biopsy (EMB) following heart transplantation has been reported in several studies. This study tried to determine the prevalence of EMB‐related iatrogenic damage over tricuspid apparatus following orthotopic heart transplantation and to evaluate its impact on the patients. Methods: Fifty patients received orthotopic heart transplantation between July 1987 and March 2005. Eleven patients were excluded from the study due to early postoperative mortality or inadequate follow‐up. The medical records of the remaining 39 patients were reviewed retrospectively for basic characteristics as well as each attempted EMB. The iatro‐genic damage of tricuspid apparatus and serial change of TR were accessed with 2‐D and Doppler echocardiography. The obtained data were analyzed for their statistical significance with SPSS (version 12.0). Results: A total of 373 biopsies were performed on the 39 patients between 1987 and 2005. The follow‐up duration was 42.9 ± 26.7 months. The prevalence of TR immediately following heart transplantation was 84.6%, with only 25.6% of patients having moderate or severe TR. At the end of the follow‐up, the prevalence of TR increased to 92.3% and 61.5% of patients having moderate or severe TR, respectively. Eight patients (20.5%) had small chordae rupture (SCR) noted after 6.6 ± 3.2 biopsies, and 10 patients (25.6%) had flail tricuspid valve (FTV) after 5.7 ± 5.1 biopsies. Of patients with SCR, 62.5% had progression of TR, and 70% of patients with FTV showed significant TR change. Conclusion: The prevalence of iatrogenic tricuspid apparatus damage was high in this study. It contributed to the progression of TR significantly regardless of the damage severity. Measurements should be taken for prevention of iatro‐genic tricuspid apparatus damage induced by EMB.

Short-term results of catheter-directed intrathrombus thrombolysis versus anticoagulation in acute proximal deep vein thrombosis

Background: Deep vein thrombosis (DVT) is a potentially progressive disease with complex clinical sequelae. The clinical practice guidelines of the American College of Chest Physicians (ACCP) recommend various treatments for all patients with objectively proven DVT. This study retrospectively compares enoxaparin with CDT on treatment efficacy and safety and the evolution of acute proximal DVT in the lower limbs. Methods: This study comprised 53 patients with acute proximal DVT, who received either CDT followed by intravenous unfractionated heparin (UFH) or adjusted subcutaneous low‐molecular‐weight heparin (LMWH) (enoxaparin) for 7–14 days. Warfarin was administered to all patients for at least 6 months. The study endpoints included the evolution of DVT and treatment efficacy and safety, which were assessed with frequent duplex ultrasounds, plethysmography, and venography. The mean duration of the follow‐up was 15.2 months. Results: In the CDT group, patency of the iliofemoral vein segment was observed in 42.3% of the patients after 1 week (p < 0.001) and in 69.2% after 6 months. In the control group, patency was present in 15.4% of the patients after 3 months and in 38.5% after 6 months (p = 0.05). Femoral venous obstruction was found in 30.8% of CDT patients and in 61.5% of the control group (p = 0.05). Furthermore, femoral venous insufficiency was present in 46.2% of the CDT group and 53.9% of the control group after 6 months (p = 0.587). After 12 months, post‐thrombotic syndrome (PTS) was found in 19.2% of the CDT patients compared to 50% of the LMWH group (p = 0.04). Conclusion: Duplex ultrasound analysis of thrombus progression is useful for assessing the treatment of a patient with acute proximal DVT. In this study, patients undergoing CDT experienced higher thrombus resolution and early recanalization of their veins, which may preserve venous function and further prevent development of post‐thrombotic syndrome.

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.

Left Ventricular Aneurysm Repair: A Comparison of Linear Versus Patch Remodeling

Background: Surgical repair of left ventricular (LV) aneurysm has been performed for around 50 years. However, the most appropriate surgical approach remains undetermined. This study was undertaken to compare the efficacy of 2 established techniques, linear versus patch remodeling, for repair of dyskinetic LV aneurysms. Methods: We retrospectively reviewed the records of 49 patients (mean age, 69.8 ± 7.3 years) who had operation for postinfarction dyskinetic LV aneurysm between 1996 and 2006. Thirty‐one patients underwent patch remodeling and 18 underwent linear repair. Short‐term and mid‐term outcomes, including complications, cardiac function and mortality, were assessed. Results: Overall inhospital surgical mortality, major complications and early hemodynamics showed no significant differences between the 2 groups. During a mean follow‐up of 44.0 ± 34.4 months, 8 patients died, with 4 due to cardiac‐related causes. Actuarial survival rates at 1, 5 and 10 years were 85.7%, 69.9% and 45.7%, respectively. Functional class improved from 2.51 ± 0.59 to 1.66 ± 0.54 among the mid‐term survivors (p < 0.001), with no significant difference between the 2 groups. Multivariate analysis identified preoperative NYHA functional class ≥ 3 as an independent risk factor for overall mortality (p = 0.008). Mid‐term follow‐up revealed that LV ejection fraction improved from 26.5 ± 7.2% to 34.1 ± 7.9% (p < 0.001) in the patch group, and from 26.3 ± 9.0% to 32.0 ± 9.2% in the linear group (p = 0.032). In contrast, right ventricular ejection fraction improved from 49.4 ± 10.1% to 52.0 ± 7.3% (p = 0.190) in the patch group, but deteriorated from 55.0 ± 6.3% to 50.3 ± 8.6% in the linear group (p = 0.029). Conclusion: These findings indicate that the 2 repair techniques have similar effectiveness with respect to short‐ and mid‐term outcomes except for right ventricular ejection fraction. We suggest that the selection of repair technique for LV aneurysms should be individualized for each patient based on aneurysm size and extent of the scarring process into the septum and subvalvular mitral apparatus.

Endoaneurysmorrhaphy and Cryoablation for Postinfarction Left Ventricular Aneurysm with Ventricular Tachycardia

Background: Early reperfusion in the acute phase of myocardial infarction and better medical treatment of consequent heart failure and tachyarrythmia have decreased the incidence of massive myocardial infarction, left ventricular (LV) aneurysm and also postinfarction‐sustained ventricular tachycardia (VT). However, for a number of patients, surgical ablation combined with aneurysm resection and myocardial revascularization remains a possible curative procedure. In this study, the efficacy of endoaneurysmorrhaphy and cryoablation was evaluated in patients with postinfarction LV aneurysm with VT. Methods: The medical records of 9 patients who underwent LV endoaneurysmorrhaphy and cryoablation for VT at Taipei Veterans General Hospital between January 1995 and August 2005 were reviewed retrospectively. Results: There were 8 men and 1 woman, with a mean age of 69.7 years (range, 52‐77 years). Preoperative VT and LV aneurysm were found in all patients, who underwent extensive cryoablation at the transitional zone of scar and viable tissue without intraoperative mapping and LV remodeling with prosthetic patch. Associated procedure included coronary artery bypass grafting in 8 patients. During follow‐up, no surgical or inhospital mortality were noted. There was 1 late sudden death at home 1.7 months after the operation. No recurrent VT was detected, and all patients showed improvement in New York Heart Association functional class (mean, 2.33 vs. 1.67; p = 0.025) and LV ejection fraction (mean, 26.3% vs. 34.1%; p =0.021). Conclusion: In patients suffering from postinfarction LV aneurysm complicated with VT, combining cryoablation and endoaneurysmorrhaphy offers good arrhythmia control and clinical outcome.

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.

S20-7 ONE STAGE OPERATION OF TOTAL ARCH REPAIR WITH STENT GRAFT IMPLANTATION AT REVERSE SLEEVE GRAFT FOR RESIDUAL TYPE A DISSECTING AORTIC ANEURYSM

of the 16th Asian Pacific Congress of Cardiology, Taipei, Taiwan, 13–16 December, 2007 41 recipients especially those with lower BMI. Our results may give a new insight into VGC usage against CMV infection.