Asian Cardiovascular and Thoracic Annals

Hydrodynamics of St. Jude Medical, Carbomedics, Advancing The Standard, and On-X bileaflet valves with an annular diameter of 25 mm were obtained using an in-vitro test system. Steady flow studies demonstrated different pressure drops due to differences in valve design, particularly the geometric orifice diameter and the opening angle. The On-X valve produced the least pressure drop, whereas the Carbomedics valve had the greatest pressure drop. In pulsatile flow experiments, the On-X and St. Jude Medical valves consistently produced the lowest mean positive pressure gradients, while the Carbomedics valve had the highest gradients. In spite of its parallel leaflets design, the On-X valve showed a closing volume as small as that of Carbomedics valve. The results indicate that a larger orifice diameter and greater opening angle can significantly reduce transvalvular pressure loss. This study also demonstrated that attempts to improve the hydrodynamic efficacy of the On-X valve were successful in reducing the pressure gradient as well as maintaining a low closing volume.

All patients who received a Carbomedics heart valve prosthesis were assessed retrospectively by interview regarding thromboembolic, hemorrhagic, or other valve-related events. In cases of such events, the patient's practitioner or cardiologist was interviewed. Hospital records were reviewed in cases of hospital admission. Included in the study were patients who had isolated replacement of the aortic or mitral valve in whom it was possible to collect all International Normalized Ratio values from discharge through follow-up. There were 148 patients with isolated aortic valve replacement and 56 with isolated mitral valve replacement. Bleeding events were 3 times more frequent than thromboembolic events. Based on our results we will apply an International Normalized Ratio between 2 and 2.5 for patients with a Carbomedics heart valve prosthesis in aortic position and ratios between 2.5 and 3 for those with a mitral valve prosthesis.

Postoperative blood loss, blood and blood-product requirements, and complications were compared for 3 commonly used doses of epsilon-aminocaproic acid in 150 patients undergoing first-time coronary artery bypass surgery. The patients were randomly assigned to one of 4 groups. Group 1 (n = 30) served as a control, group 2 (n = 30) received a single dose of 150 mg·kg⁻¹ of epsilon-aminocaproic acid after anesthetic induction, group 3 (n = 30) received a loading dose of 150 mg·kg⁻¹ followed by infusion of 1 g·h⁻¹ for 6 hours, and group 4 (n = 60) received doses of 150 mg·kg⁻¹ at induction, on bypass, and after protamine. No patients, including those who had endarterectomies, experienced any complications attributable to epsilon-aminocaproic acid administration. All patients who received epsilon-aminocaproic acid had significantly less bleeding compared to controls. Groups 3 and 4 had the least blood loss and packed-cell requirements.

To evaluate serum troponin T as a marker of perioperative myocardial infarction, 50 patients undergoing coronary artery bypass grafting were divided into 2 groups. Group A (14 patients) had serum creatine kinase MB-isoenzyme levels above 100 U·L⁻¹ and electrocardiographic changes indicative of infarction. Group B (36 patients) had creatine kinase MB levels below 100 U·L⁻¹ and no electrocardiographic changes. Blood samples were obtained preoperatively, 6 hours after aortic declamping, and on postoperative day 1, 2, and 3. Following surgery, all patients had increased levels of troponin T and creatine kinase MB. Troponin T was significantly higher in group A compared to group B at 6 hours, day 1, and day 2 postoperatively. Creatine kinase MB levels were significantly higher in group A compared to group B at 6 hours and day 1 postoperatively. The increased levels of troponin T in patients without myocardial infarction suggest that some operative myocardial damage occurred. Patients with perioperative myocardial infarction had significantly higher levels of troponin T up to postoperative day 2, whereas creatine kinase MB levels were almost normal by day 2. This suggests that troponin T may be used up to 2 days postoperatively for detection of myocardial infarction.

Six patients with coronary artery fistula were treated surgically between October 1977 and November 1998. The clinical manifestations, diagnostic criteria, indications for operation, and surgical techniques were evaluated. One patient died from ventricular fibrillation on the 2nd postoperative day. The outcome for the other 5 patients was good; symptoms and heart murmurs disappeared and all are alive and well after 10 to 21 years of follow-up. It was concluded that analysis of clinical data can confirm the diagnosis and this condition can be treated satisfactorily by suitable surgery.

Between January 1989 and December 1998, 13 patients (7 males) aged 3 months to 32 years, underwent surgery for anomalous left coronary artery from the pulmonary artery. Eight presented with congestive cardiac failure and all had evidence of left ventricular dysfunction. One patient had associated tetralogy of Fallot. Preoperative diagnosis was established by echocardiography and cineangiography. Nine patients underwent Takeuchi repair and 4 had direct implantation of the anomalous artery into the aorta. There were 2 postoperative deaths due to low cardiac output. In survivors, serial echocardiograms demonstrated significant improvement in left ventricular function 3 months to 10 years after surgery. Postoperative angiograms in 4 patients showed a patent aortocoronary tunnel in 3 who underwent Takeuchi repair and a patent aortocoronary anastomosis in one who had direct implantation of the anomalous artery into the aorta. It was concluded that early establishment of a two-coronary system gave gratifying short-term and long-term results.

To evaluate myocardial impairment induced by uncontrolled reoxygenation, the effects of hypoxia-reoxygenation were compared with ischemia-reperfusion in isolated rat hearts. After stabilization, 2 groups (n = 8) of Langendorff-perfused rat hearts were exposed to 40 minutes of ischemia (10% of baseline flow) or hypoxia (10% of baseline oxygen content) followed by a sudden return to baseline conditions (reperfusion or reoxygenation). The O₂ content was identical for the two groups during baseline conditions, O₂ shortage, and O₂ readmission. Metabolic (lactate production) and functional parameters (heart rate, peak systolic pressure, left ventricular developed pressure, maximal contraction and relaxation rates, end-diastolic pressure, coronary perfusion pressure) were recorded at the end of stabilization, after O₂ deficiency, and after 2 minutes of reoxygenation. Systolic function was significantly depressed after ischemia (p < 0.0001) but completely recovered to baseline values after 2 minutes of reperfusion. In contrast, systolic function was less severely depressed after hypoxia but failed to return to baseline after 2 minutes of reoxygenation. Diastolic function, unchanged during ischemia-reperfusion, remained significantly impaired during hypoxia-reoxygenation.

Between 1965 and 1995, 552 patients underwent closure of isolated secundum atrial septal defect, of whom 24 (4.3%) were infants with a mean age of 238.5 ± 13.8 days (range, 90 to 348 days). Mean weight was 6 ± 0.3 kg (range, 3.5 to 9 kg). Twenty-two had noted failure to thrive and 13 had chest infections. Direct closure was carried out in 20 and 4 underwent patch closure. There were 3 (12.5%) early deaths (intraoperatively, 5 hours, and 2 days postoperatively). Three patients had pulmonary hypertension with pulmonary arterial to systemic arterial pressure ratios of 0.74 to 0.83 preoperatively. Of 21 survivors, 13 were extubated within 24 hours and 8 within 72 hours of surgery. Mean hospital stay was 16.2 ± 8.2 days. There were 2 late deaths; one from pneumonia at 177 days postoperatively and another patient with a severe neuromuscular disorder who could not be extubated, died 328 days postoperatively. We concluded that some infants require early surgery and an atrial septal defect can be closed safely in infancy but the risk increases in patients with pulmonary vascular disease. The etiology of pulmonary vascular disease in such patients remains unclear.

This retrospective study of 6 cases of atypical carcinoid tumor was carried out to highlight their clinicopathological features and behavior. All patients were over 40 years of age and were treated by surgical excision of the tumor. Four tumors were central and 2 were peripherally located in the lung. Grossly, the tumors were large with spotted areas of necrosis. Microscopically, all tumors had a typical carcinoid pattern with spotted areas of necrosis and mitotic activity in the range of 2 to 5 per 10 high-power fields. On immunohistochemistry, the tumors were positive for neuron-specific enolase and cytokeratin. Follow-up ranging from 1 to 5 years was available in 4 patients; 2 are currently alive, 1 with local recurrence and distant metastasis one year postoperatively, the other with no disease after 5 years. Two patients died; one had a local recurrence at 2 years and the other had liver metastasis at 3 years.

Forty-two symptomatic patients underwent both electron-beam computed tomo-graphic calcium scoring and coronary angiography. Correlation between coronary artery calcium score and angiographic coronary disease showed a high specificity (90%) but low sensitivity (50%). The low negative predictive value of 36% suggests that electron-beam computed tomography is not useful in symptomatic patients.

Thromboembolic complications and valve thrombosis in pericardial xenografts are rare. A case of early postoperative thrombosis of a pericardial xenograft is described.

A 22-year-old female suffering from idiopathic long-QT syndrome complicated by frequent syncope, torsade-de-pointes-type ventricular tachycardia, and asthma, was successfully treated by video-assisted extensive left second and third thoracic sympathetic ganglionectomy, instead of left stellate and first thoracic ganglio-nectomy, to avoid postoperative Horner's syndrome. The QT interval was significantly shortened from 0.6 to 0.43 seconds four days after the surgery. It remained at 0.43 seconds during a 3-month follow-up with no recurrence of tachycardia or syncope.

Spontaneous dissection of a coronary artery is a rare cause of obstructive coronary artery disease and sudden death. We report a case of spontaneous dissection of the left main coronary artery, which manifested as ischemic heart disease and was successfully treated by emergency myocardial revascularization. Prompt diagnosis and surgical revascularization are crucial for survival.

An asymptomatic 24-year-old man underwent surgical correction of an aorto-left ventricular tunnel. A 1-cm opening was found 1 cm above the commissure of the left and right coronary cusps, which communicated with the left ventricle. It was successfully closed by direct suture.

A 20-year-old man with a 5-year history of ulcerative colitis presented with sudden chest pain and diarrhea. Chest radiography, echocardiography, and computed tomography demonstrated pneumomediastinum and pneumopericardium. The condition resolved completely after one week.

A 24-year-old man was investigated for dyspnea and swelling of the right side of the neck with pain in the right shoulder, which had developed over the previous year. Hydatid cyst of the right first rib was diagnosed by chest radiography and computed tomography. Serology for hydatid disease was negative. The cysts and the first rib were excised via a right thoracotomy. The postoperative course was uneventful. Histology revealed multilocular echinococcal lesions.

A 65-year-old man had a 6 × 4 × 4 cm myxoma adhering to the posterior leaflet of the mitral valve. He underwent successful myxoma resection and mitral valve replacement.

An unusual case of primary leiomyosarcoma presenting as a cystic mass is reported. An 86-year-old man underwent resection of a large cystic mass measuring 15 cm in diameter, arising from the left lower lobe of the lung. Histology of the resected specimen showed primary pulmonary leiomyosarcoma. The patient made a good recovery.

Multiple anastomotic suture lines in aortic aneurysm surgery are prone to bleeding. To improve hemostasis, a 15-mm-wide strip of native pericardium was used to reinforce all anastomotic suture lines. This technique was used in 4 consecutive patients who underwent modified Bentall and elephant trunk procedures for extensive aortic aneurysm. The mean cardiopulmonary bypass time was 230 minutes and the mean aortic crossclamp time was 92 minutes. Mean blood loss through the mediastinal drainage tubes was 193 mL in the first 12 hours postoperatively and the mean blood requirement was 3 units. It was concluded that this technique markedly improved hemostasis in extensive aortic aneurysm surgery.

A modification of the Nicks procedure to obtain a firm blood-tight aortoplasty is described. Autologous pericardium was used in a bilayer arrangement with a sandwich suture technique. It was found to be an easy and effective way of decreasing bleeding. It may also prevent true and false aneurysms.

A simplified method of reinforced sternal closure is described. Figure-of-8-shaped sutures of no. 5 stainless steel wire are inserted with 2 Sterna-Bands between them. The advantages of this technique are simplicity, effectiveness, and speed.

The management of complex bronchopleural fistula remains a major therapeutic challenge for the thoracic surgeon. Although the incidence of bronchopleural fistula following lung resection has decreased in recent years to 1% to 2%, when it occurs, it is associated with significant morbidity and mortality. Using illustrative cases, the epidemiology and pathophysiology of bronchopleural fistula are reviewed and operative strategies are discussed. Algorithms for the diagnosis and treatment are suggested on the basis of cases described in the literature. The best way to prevent a fistula is to rigorously follow the surgical techniques described, with minimal devascularization of the bronchus and prophylactic coverage of the stump in high-risk patients. Successful management of a fistula is combined with treatment of the associated empyema cavity. Definitive repair should be accomplished expeditiously, minimizing the number of procedures performed. When treatment is protracted, secondary complications are more likely and survival is adversely affected. The first step should be control of active infection and adequate drainage of the hemithorax, followed by timely repair of the bronchopleural fistula when possible and reinforcement of the stump with vascularized tissue. If a residual cavity is present it must also be obliterated with a pedicled muscle flap.

Myocardial infarction was the underlying event in the majority of deaths from cardiovascular disease in Western countries in the past quarter-century. The introduction of angiotensin-converting enzyme inhibitors to the treatment of heart failure following myocardial infarction was a major advance in the last 10 years. However, the role of cardiac angiotensin-converting enzyme during postinfarction cardiac remodeling remains to be elucidated. Experimental studies demonstrated that angiotensin-converting enzyme inhibitors administered one week before myocardial infarction could limit infarct size, improve cardiac function, and prevent cardiac hypertrophy. Numerous large-scale clinical trials have shown that angiotensin-converting enzyme inhibitors are safe and can reduce mortality and the occurrence of severe left ventricular dysfunction after myocardial infarction. This review focuses on the effects of these inhibitors in experimental studies and in multicenter clinical trials.