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Biomedical subjects

A P Yim

Publications and source records attributed to A P Yim.

At least 19 recordsLinked to original sources
PubMed1999

A survey on partial left ventriculectomy in the Asia-Pacific region.

BACKGROUND: There has been increasing interest in partial left ventriculectomy as a new therapy for end-stage heart failure. Because the most significant impact of this development is likely to be in regions where heart transplantation is largely unavailable, we conducted a survey among a group of cardiac surgeons based in the Asia-Pacific region to evaluate their overall views on partial left ventriculectomy procedures. METHODS: A questionnaire was sent to surgeons from 65 major institutions in 17 countries and regions in the Asia-Pacific. Questions examined current demographics and opinions regarding potential application and future prospects of this operation. RESULTS: Surveyed surgeons were based in equal proportions in academic, government, and private practice institutions. One third of respondents have already performed partial left ventriculectomy operations, largely in small numbers. In total, 86 procedures were performed with 75% hospital survival rate. Failures were thought to be caused by limited knowledge about patient selection criteria and lack of experience with operative technique and perioperative care. The majority of respondents believe that partial left ventriculectomy is potentially a valuable intervention and intend to perform more cases. Nevertheless, most surgeons identified the need to have larger clinical experience, to perform randomized trials against other therapeutic modalities, and to improve perioperative care. CONCLUSIONS: Although all surgeons recognize that more knowledge is needed before partial left ventriculectomy becomes a standard procedure, it is clear from this survey that the procedure has rapidly gained interest, with more surgeons seeking to learn it.

Cardiac Volume↗
PubMed1999

Favorable scanning electron microscopic findings of stapled saphenous vein-carotid artery anastomoses.

BACKGROUND: In the progress toward "off-pump" endoscopic coronary artery surgical procedures, new techniques for coronary artery anastomoses are being developed. One such approach is the use of nonpenetrating titanium clips. We evaluated the quality of anastomoses achieved using this technique in a porcine model of saphenous vein-carotid artery grafting using scanning electron microscopy. METHODS: Bilateral saphenous vein-carotid artery interposition grafts were implanted in 10 "white race" pigs, using the nonpenetrating clips in one side of the neck and conventional hand suturing on the opposite side. One week after operation, the grafts were harvested. RESULTS: All grafts were patent 7 days after operation, and 40 anastomoses underwent scanning electron microscopic study. In all samples, the luminal surfaces of both the carotid artery and vein graft were covered by a continuous layer of endothelial cells up to the anastomosis. Anastomotic sites in all clipped samples and most of the sutured anastomoses were completely endothelialized, and anastomotic clefts were indistinguishable. However, in 25% of sutured specimens, the suture material remained clearly visible inside the lumen of the vessel, and the subendothelial matrix remained exposed, with extensive fibrin, red blood cells, and platelet deposition on its surface. CONCLUSIONS: Because the endothelial coverage consistently appeared to be complete and the subendothelial matrix was not exposed, it is likely that the risk of early anastomotic thrombosis is reduced by using the nonpenetrating titanium clips.

Anastomosis, Surgical↗
PubMed1999

A Chinese thoracic surgeon and his two decisions.

Doctor Wu Ying-Kai is known to many in the thoracic surgical academia worldwide. This article focuses on the two decisions he made at the ages of 33 and 70 that profoundly influenced the development of thoracic and cardiovascular medicine in a country with one quarter of the world population. His successful career was gauged not so much by the position he achieved, but by the obstacles he had to overcome to achieve it.

China↗
PubMed1999

Does steroid pretreatment increase endotoxin release during clinical cardiopulmonary bypass?

OBJECTIVE: The mechanism involved in the endotoxemia frequently recognized during cardiopulmonary bypass remains unclear. It has also been suggested that endotoxin levels were higher in steroid-pretreated patients undergoing cardiopulmonary bypass. METHODS: Twenty patients undergoing cardiopulmonary bypass were randomly pretreated with steroids (methylprednisolone, 30 mg/kg) or placebo. Blood samples for endotoxin measurement were drawn simultaneously from the superior and inferior venae cavae before heparin administration, 5 and 50 minutes after the onset of bypass, 5 minutes after aortic declamping, at the end of bypass, and 1, 2, and 20 hours after the end of cardiopulmonary bypass. RESULTS: The perioperative variables in the two groups were similar. Blood endotoxin levels were higher in the inferior vena cava than in the superior vena cava immediately after the onset of bypass. Endotoxin levels in inferior vena cava blood were significantly lower in steroid-pretreated patients than those in patients not receiving steroids. CONCLUSIONS: Endotoxin is released during cardiopulmonary bypass from the region drained by the inferior vena cava. Steroid pretreatment may actually reduce endotoxin release during bypass.

Aged↗
PubMed1999

Video-assisted thoracoscopic thymectomy for myasthenia gravis.

Thymectomy is an established therapy in the management of generalized myasthenia gravis, in addition to medical treatment. However, the optimal surgical approach to thymectomy has remained controversial. There are advocates for transternal, transcervical approaches or "maximal" thymectomy. Video-assisted thoracic surgery (VATS) presents a new approach to thymectomy and forms the basis of this article, in which we discuss patient selection, technique, and results. We believe complete thymectomy, comparable with the transternal approach, could be achieved by VATS. Our intermediate-term results compare well with other surgical techniques. By minimizing chest wall trauma, VATS not only causes less postoperative pain, shortens hospital stay, gives better cosmetic results but also leads to wider acceptance by patients (and their neurologists) for earlier surgery. However, the true role of this approach in thoracic surgery awaits long-term results.

Anesthesia, General↗
PubMed1999

Video-assisted thoracic surgery: a renaissance in surgical therapy.

Within a few years, video-assisted thoracic surgery (VATS) has become the accepted or preferred approach over a wide range of thoracic procedures. The authors review the development of this technique, the basic operative strategies and the current surgical indications. Technical pitfalls and future developments are also discussed.

Humans↗
PubMed1999

Routine intraoperative angiography improves the early patency of coronary grafts performed on the beating heart.

OBJECTIVES: The techniques of performing coronary revascularization without cardiopulmonary bypass are rapidly evolving. However, concern remains regarding the accuracy of coronary artery anastomoses performed on the beating heart. This report reviews the use of intraoperative angiography in the critical appraisal of "off-pump" coronary artery bypass graft (CABG) surgery. PATIENTS: Intraoperative angiography was performed in 24 consecutive patients undergoing CABG surgery without cardiopulmonary bypass. In all, 24 left internal mammary artery (LIMA) grafts and 18 saphenous vein bypass grafts were assessed for patency, anastomosis quality, distal and proximal runoff, and correct placement. RESULTS: All of the saphenous vein-to-coronary artery anastomoses were widely patent, although two patients (8%) required revision of their LIMA grafts on the basis of angiographic findings. CONCLUSION: Intraoperative angiography permits the surgeon to immediately appraise the CABG and to revise, if necessary, any graft abnormality, thus potentially eliminating the need for early repeated surgery. The practice of routine intraoperative angiography is likely to improve the outcome of CABG surgery on the beating heart.

Coronary Angiography↗
PubMed1999

Video-assisted thoracoscopic thymectomy.

Video-assisted thoracoscopic surgery (VATS) provides a new, alternative approach to thymectomy and has several advantages over the other established techniques. However, even among surgeons using this approach, there are differences in the actual technique. We prefer the right approach using conventional instruments. The rationale behind our technique is discussed.

Humans↗
PubMed1999

Can cardioplegia management influence cytokine responses during clinical cardiopulmonary bypass?

BACKGROUND: Cytokines play an important role in the inflammatory response associated with cardiopulmonary bypass (CPB) and may contribute to postoperative complications. Although it has been shown that the production of tumor necrosis factor a (TNF-a) and interleukin (IL)-6 were higher following normothermic CPB than hypothermic CPB, whether different cardioplegic management could influence the release of cytokines remains unknown. METHODS: We compared the blood concentrations of four cytokines (TNF-a, IL-6, IL-8, and IL-10) in two groups of patients undergoing complete revascularization with CPB in the same study period. Seventeen patients received cold crystalloid cardioplegia at a Belgian center (group-CC), while 21 patients received warm blood cardioplegia at a center in Hong Kong (group-WB). Blood samples were collected before and after surgery in each patient. RESULTS: There were no differences between the 2 groups in terms of age, sex ratio, number of grafts, duration of CPB and aortic crossclamping. All patients survived their hospital stay. The levels of TNF-a, IL-6 and IL-8 after surgery were higher in group-CC than in group-WB. However, IL-10 levels were significantly lower at the end of surgery in group-CC than in group-WB. CONCLUSIONS: Our data suggest that the use of warm blood cardioplegia, rather than cold crystalloid cardioplegia, may reduce the inflammatory response to CPB. This observation warrants future randomized investigation to determine its clinical relevance.

Blood↗
PubMed1998

Multimodality treatment of primary lymphoepithelioma-like carcinoma of the lung.

BACKGROUND: Lymphoepithelioma-like carcinoma (LELC) of the lung occurs at a higher frequency in Asian compared with Western patients. Its association with Epstein-Barr virus varies among different ethnic groups. METHODS: Nine patients with primary LELC of the lung treated at a single institution with a multimodality approach comprised of surgery, chemotherapy, and radiotherapy are reported. Chemotherapy was comprised of cisplatin, 100 mg/m2, on Day 1 and 5-fluorouracil, 1 g/m2, on Days 2, 3, and 4. RESULTS: Five male and 4 female patients were treated over a 3-year period. Eight patients were non-smokers. Three patients had operable disease. Two of these patients received adjuvant radiotherapy or chemotherapy and remained free of recurrence at 18 and 20 months, respectively; 1 patient received no adjuvant treatment, and palliative chemotherapy was given for subsequent recurrent disease. Six patients had inoperable disease and received palliative chemotherapy +/- radiotherapy. Five patients had distant metastatic disease at presentation. Of the 7 patients who were evaluable for response to chemotherapy, 71.4% had a partial response and 28.6% had progressive disease. One patient who was evaluable for response to radiotherapy achieved a partial response. CONCLUSIONS: Primary LELC of the lung has a high rate of systemic metastasis and is highly chemosensitive. A multimodality approach to the management of this disease is recommended.

Adult↗
PubMed1998

Video-assisted interventional bronchoscopy. The Hong Kong experience.

BACKGROUND: Major airway obstruction due to benign or malignant etiology is not uncommon and is always distressing. Intraluminal stenting has been shown to be a safe and effective approach for symptomatic relief in selected patients based on the European and North American experience. METHODS: We reviewed our experience in Hong Kong on airway stenting over a 19-month period. RESULTS: From February 1994 to August 1995, 33 silicone stents (Dumon stent, Cometh, Marseille, France) were placed in 23 patients (20 males, three females with mean age 61.4 years, range from 26 to 81). Eighteen stents were placed in the trachea, nine in the left main stem, five in the right main stem, and one Y-stent over the carina. Twelve patients had esophageal carcinoma involving the airway, seven had bronchial carcinoma, one had metastatic carcinoma, and three had benign strictures (of which two were due to tuberculosis). There was no procedural related mortality. Stent migration occurred in four patients (17%) and required stent change. Symptoms were improved in all patients as documented by the visual analogue scale. CONCLUSION: Our experience represents the "stentable" diseases seen in Hong Kong, where carcinoma of the esophagus (and tuberculosis) remains prevalent. We conclude that intraluminal stenting remains a safe and effective approach in selected patients with critical airway stenosis. Complications, however, do exist and should be realized by the operator, the patients, and their families.

Adult↗
PubMed1998

Thoracoscopic operations on reoperated chests.

BACKGROUND: A previous operation is generally considered to be a relative contraindication to the minimal access approach. We reviewed our combined experience from three centers with video-assisted thoracic surgery on reoperated chests. METHODS: From September 1992 to December 1996, 2,477 patients underwent video-assisted thoracic surgery of whom 40 patients (33 men; age range, 9 to 78 years) had prior operations on the ipsilateral side of the chest: 23 after prior open procedures (22 thoracotomies, 1 median sternotomy) and 17 after video-assisted thoracic surgery. The second procedures consisted of bullectomy or bulla ligation (8), mediastinal and hilar mass biopsy (8), wedge lung resection (6), pericardial window (5), lung volume reduction (4), redo thoracodorsal sympathectomy (3), talc insufflation alone (3), decortication (2), and suturing of a pleural rent (1). RESULTS: Adhesions were noted in all patients ranging from minimal to strong fibrous adhesions. However, in only 2 patients (5%) were the procedures abandoned because of adhesions. Video-assisted thoracic surgery was safely completed in all other patients. There was no mortality or intraoperative complications and mean hospital stay was 5.1 +/- 3.2 days (range, 0 to 17 days). CONCLUSIONS: Video-assisted thoracic surgery on reoperated chests is feasible and does not carry a higher morbidity or mortality compared with first-time operations, even though it may be technically more difficult. Experience and clinical judgment, however, are required to select these patients for reoperation with video-assisted thoracic surgery.

Adolescent↗