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Biomedical subjects

M G Song

Publications and source records attributed to M G Song.

At least 19 recordsLinked to original sources
PubMed2001

Atrial fibrillation surgery simplified with cryoablation to improve left atrial function.

BACKGROUND: The Maze procedure restores atrial fibrillation to normal sinus rhythm. However, concurrent left atrial functional recovery is not always achieved. To address this limitation, a modification using linear cryoablation is described. METHODS: Between July 1997 and December 1999, 83 patients received atrial fibrillation surgery in association with mitral valve surgery with or without additional concurrent procedures by either the conventional technique, group I (n = 30) or the modified technique, group II (n = 53). Onset of sinus conversion and echocardiographic assessment of postoperative left ventricular function, left atrial size, and mitral A-wave velocity were compared in the early postoperative period and 6 months after surgery. RESULTS: Sinus conversion occurred significantly earlier in group II, 2.4 +/- 5 days versus group I, 7.0 +/- 10 days. The mean transmitral A-wave velocity and the incidence of A-wave appearance in the early postoperative period and 6 months postoperatively were greater in group II than group I. CONCLUSIONS: With the current modification, restoration of sinus rhythm and superior left atrial contractile function occurred earlier than with the standard Maze III technique.

Atrial Fibrillation↗
PubMed2001

Different clinical features of aortic intramural hematoma versus dissection involving the ascending aorta.

OBJECTIVES: The goal of this study was to test the hypothesis that the absence of direct flow communication through intimal tear in aortic intramural hematoma (AIH) involving the ascending aorta has different clinical impact on clinical course compared with typical aortic dissection (AD). BACKGROUND: Although emergent surgical repair has been applied for patients with proximal AIH as if it was typical AD, the natural history of proximal AIH is not known clearly yet. METHODS: Direct comparison of the clinical data of 81 patients with proximal AD and 24 patients with AIH was performed retrospectively. RESULTS: Patients with AIH were older (67 +/- 10 vs. 50 +/- 13, p = 0.001), and female gender was more predominant in AIH (19/24 vs. 29/81, p = 0.001). The development of mediastinal hemorrhage and pericardial and pleural effusion was more frequent in patients with AIH than it was in patients with AD. Although medical treatment was more frequently selected in the AIH group (75% vs. 15%, p = 0.001) due to old age and other associated medical diseases, the mortality rate with medical treatment was much lower in patients with AIH than it was in patients with AD (6% vs. 58%, p = 0.003). In follow-up imaging studies of 13 patients who survived AIH without surgical repair, seven patients showed complete resolution. Typical AD developed in three patients, and the other three patients showed focal AD only in the descending aorta. The two-year survival rate did not show significant difference (84% +/- 6% in AIH vs. 76% +/- 17% in AD, p = 0.47). CONCLUSIONS: Absence of continuous flow communication can explain a more favorable clinical course of AIH than for AD, and medical treatment with frequent imaging follow-up and timed elective surgery in cases with complications can be a rational option for patients with proximal AIH.

Age Distribution↗
PubMed2001

Anastomosis of vessels less than 2 mm with the vascular clip system clip applier.

Sutures may cause endothelial trauma and occlusion. The vascular clip system (VCS) clip applier may minimize endothelial injury. Fourteen carotid arteries of nine adult rabbits were transected and re-anastomosed with either #7-0 polypropylene (Group I, n=8) or VCS clips (Group II, n=6). The animals were sacrificed at 1, 3, 8, 14, and 30 days postoperatively. The operation time and bleeding amount were checked for each anastomosis. Carotid angiograms, photography, H&E staining and scanning electron microscopy (SEM) were performed. Fibrin and thrombus, inflammatory cell infiltration, endothelial disruption, luminal distortion, fibrosis, and wall thickening were compared. The luminal diameter was greater in group II. There were minimal differences in thrombosis, wall thickening and fibrosis between the two groups. However, fibrin, inflammatory cell infiltration, multinucleated giant cell formation, endothelial disruption, and luminal distortion were greater in group I. On SEM, group I showed trans-mural penetration. In contrast, group II showed suture margin eversion and no transmural penetration. Stenosis was greater in group I than in group II on carotid angiogram. The operation time was shorter in group II than in group I, i.e. 5+/-1.4 min vs. 11+/-3.8 min, respectively. The current data showed similar or superior results with VCS clips in comparison to conventional suturing with polypropylene.

Angiography↗
PubMed2001

Clinical characteristics of constrictive pericarditis diagnosed by echo-Doppler technique in Korea.

A retrospective analysis of clinical data of 71 patients with constrictive pericarditis (CP) diagnosed by echo-Doppler technique (mean age, 49+/-17) was done. In 27 patients (38%), the etiology was unknown, and the three most frequent identifiable causes were tuberculosis (23/71, 32%), cardiac surgery (8/71, 11%), and mediastinal irradiation (6/71, 9%). Pericardiectomy was performed in 35 patients (49%) with a surgical mortality of 6% (2/35), and 11 patients (15%, 11/ 71) showed complete resolution of constrictive physiology with medical treatment. Patients with transient CP were characterized by absence of pericardial calcification, shorter symptom duration, and higher incidence of fever, weight loss, and tuberculosis. The 5-yr survival rates of patients with transient CP and those undergoing pericardiectomy were 100% and 85+/-6%, respectively, which were significantly higher than that of patients without undergoing pericardiectomy (33+/-17%, p=0.0083). Mediastinal irradiation, higher functional class, low voltage in ECG, low serum albumin, and old age were the independent variables associated with a higher mortality. Tuberculosis is still the most important etiology of CP in Korea, and not infrequently, it may cause transient CP. Early diagnosis and decision-making using follow-up echocardiography are crucial to improve the prognosis of patients with CP.

Adult↗
PubMed2000

Routine minimally invasive aortic valve procedures.

BACKGROUND: Due to the lack of objective evidence supporting the advantages and early technical difficulties, minimally invasive aortic valve procedures were performed on a highly selective rather than routine basis. METHODS: From September 1997 to February 1999, one surgeon routinely used upper or transverse minimally invasive sternotomy to perform 46 consecutive cases of aortic valve procedures (M), whereas two other surgeons performed 40 aortic valve procedures through a conventional sternotomy (C). RESULTS: More time consuming and technically demanding surgeries were done in M. There was one death in each group. Aortic clamp time was longer in M (93+/-40 vs 59+/-24 min, P=0.001). There were no differences in operating time, pump time, intubation duration, bleeding and intensive care unit stay. The advantages of minimally invasive aortic valve operation included better postoperative ejection fraction (58+/-17 vs 51+/-10%, P=0.04), decreased pain score (3+/-2 vs 5+/-2, P=0.004), less transfusion (19 vs 55%, P=0.02), shorter duration of chest tube drainage, and cosmetically more acceptable surgical wound (6.8+/-2.2 vs 5.2+/-2.0, P=0.018). From our series, we could not find any negative effects of minimal access surgery. CONCLUSIONS: Our study demonstrated that aortic valve surgeries could be performed routinely by the minimally invasive approach with a high degree of effectiveness and safety.

Adolescent↗
PubMed1999

Different remodeling of descending thoracic aorta after acute event in aortic intramural hemorrhage versus aortic dissection.

The natural healing process of medically treated aortic dissection (AD) and aortic intramural hemorrhage (AIH) developed in the descending thoracic aorta was compared to test the hypothesis that absence of intimal tear and flow communication in AIH may have different impact on the remodeling of the affected aorta after the acute event. In 25 patients with AD and 20 with AIH involving distal descending thoracic aorta stabilized with medical treatment, follow-up (mean 9 months) transesophageal echocardiography was performed to measure the maximal dimensions of aorta, true lumen, false lumen in AD, and abnormal wall thickening in AIH. The sex ratio, prevalence of hypertension, baseline maximal dimension, and longitudinal extent of the affected aorta did not show any significant difference in both groups. Patients with AIH were older than those with AD (63 +/- 10 vs 50 +/- 9, p <0.01). Disappearance of abnormal wall thickening with complete restoration of the aorta occurred in 70% (14 of 20) patients with AIH, which was significantly more frequent than in AD (8%, p <0.01). In AD, progressive dilatation of the aorta with continuous flow communication in the false lumen resulted in larger dimension of the aorta than in AIH (44 +/- 13 vs 35 +/- 7 mm, p <0.01). Absence of persistent flow communication resulted in a favorable remodeling process in AIH affecting distal descending aorta. This finding, along with different mean age in AIH and AD, may suggest that AIH is not just a precursor of overt AD but a distinct disease entity with different pathophysiology.

Acute Disease↗
PubMed1999

Resurfacing of facial angiofibromas in tuberous sclerosis patients using CO2 laser with flashscanner.

BACKGROUND: Angiofibromas are a common presentation of tuberous sclerosis. They cause considerable cosmetic and hygienic morbidity for patients. Treatments of angiofibromas have included curettage, cryosurgery, chemical peel, dermabrasion, shave excision, and 13-cis retinoic acid. Results from these modalities in many cases were not satisfactory from a cosmetic standpoint. Copper vapor, argon, pulsed dye, and CO2 lasers have been used with success in isolated cases. OBJECTIVE: The purpose of this study was to evaluate the efficacy of CO2 laser resurfacing with flashscanner in the treatment of facial angiofibromas. METHODS: Two patients with angiofibromas on the face were treated with a CO2 laser with flashscanner. The cheek and nose were treated in one patient, and entire face was done in the other. RESULTS: Both patients showed remarkable cosmetic improvements without scarring. Mild hyperpigmentation was found in both patients, which disappeared in 1 month with the application of topical agents. Facial erythema persisted about 2 months in both patients. CONCLUSION: A CO2 laser equipped with flashscanner causes less residual thermal damage than conventional CO2 lasers and enables controlled depth vaporization for more precise and regular removal of angiofibromas. In whole-face resurfacing, more cosmetically acceptable results are possible because localized treatment leaves marginal prominences. Laser resurfacing is an effective alternative in the treatment of multiple protuberant angiofibromas even though we cannot permanently clear these lesions due to their nature.

Adult↗
PubMed1999

Left ventricular muscle mass regression after aortic valve replacement.

Implanting a valve that will reduce left ventricular mass is critical in aortic stenosis. Regression of left ventricular hypertrophy in 46 aortic valve replacement (AVR) patients receiving a St. Jude Medical (SJM) valve was assessed by serial electrocardiographic and echocardiographic studies during the preoperative, immediate, and late postoperative periods. The patients were divided into three groups according to valve size; 19 mm group (n=9), 21 mm group (n=20), and 23+mm group (n=17). There was no surgical mortality. The NYHA functional class improved from an average of 2.2+/-0.8 preoperatively to 1.3+/-0.5 post-operatively. Left ventricular muscle mass index (LVMI) regression failed to reach statistical significance in the 19 mm group, whereas in the other two groups a steady decrease in the LVMI occurred with follow up. ECG findings were less remarkable showing insignificant differences in voltage among the three groups (p=0.000). In conclusion, the current data suggest that the 19 mm SJM valve may not result in satisfactory left ventricular muscle mass regression despite adequate function, even in small patients. Therefore, additional procedures to accommodate a larger valve may be warranted in the aortic annulus smaller than 21 mm.

Adult↗
PubMed1998

Clinical and echocardiographic outcomes of aortic intramural hemorrhage compared with acute aortic dissection.

Aortic intramural hemorrhage (IMH), which presents clinical manifestations identical to those of acute aortic dissection, is different from aortic dissection in terms of the absence of intimal tear and communication of blood flow between the true and false lumen. This study was conducted for the purpose of diagnosing IMH by transesophageal echocardiography (TEE) prospectively and comparing the clinical and echocardiographic outcome of IMH with aortic dissection. Between August 1991 and November 1996, 27 IMHs and 73 acute aortic dissections were diagnosed using TEE in 202 consecutive patients with suspected aortic dissections. The TEE diagnoses of IMH and aortic dissection were initially compared with computed tomography and magnetic resonance imaging and later confirmed by operative findings (n = 37) or follow-up changes (n = 12). In the 49 patients whose diagnosis was confirmed by operation or follow-up changes, the sensitivity and specificity of TEE for the diagnosis of IMH were 27 of 27 (100%) and 20 of 22 (91%), respectively. There were 11 deaths in 73 patients (15%) from acute aortic dissection and 1 death in 27 patients (4%) from IMH during a follow-up of 1.7+/-1.5 years (p = NS). Stanford classification and types of treatment were not related to death in both groups. Complications developed less often in patients with IMH (3 of 27) than in those with acute aortic dissection (24 of 73), and no death occurred in patients with uncomplicated IMH who were medically treated. A follow-up imaging study of 12 IMH patients showed complete resolution in 8, regression in 3, and progression in 1 patient. TEE is accurate in the diagnosis of IMH and IMH has a lower incidence of complications than aortic dissection because of the absence of intimal tear and communication of blood flow in the false lumen.

Acute Disease↗
PubMed1994

Radiologic assessment in pulmonary lobar transplantation.

UNLABELLED: Pulmonary lobar transplantation provides a clue to the acute donor shortage. To examine the experimental and clinical applicability of lobar transplantation, the authors observed the extent of lung expansion and infiltrate in the allografted lobe through the sequential analysis of the early chest roentgenograms. MATERIALS AND METHODS: Twenty two mongrel dogs weighting 17 kg on average were used. Donor lung bloc was taken and flushed with Euro-Collins solution. The left lower lobar bloc was procured and implanted in the pneumonectomized recipient dog. The anastomosis was performed in the order of the pulmonary vein, artery, and bronchus. To assess the radiological pattern in the lobar allograft, a grading system was designed according to the extent of lung expansion and infiltrate. RESULTS: A) Expansion pattern: Good to excellent lung expansion was seen on postoperative day 0 in 6 out of 10 dogs; on day 1, 4/7; day 2, 3/12; day 3, 1/1; and day 4, 1/3, respectively. Radiographs on day 6, 7, and 12 also showed good expansion in one dog. B) Lung opacity pattern: Clear to minimal infiltrates were seen on day 0 in 8 out of 10 dogs; day 1, 7/17; day 2, 2/12; and day 4, 1/3. The same appearances were detected in a single dog on day 6, 7, and 12. C) Expansion-opacity correlation pattern: Radiographs on postoperative day 0 showed good expansion with mild infiltrates, and excellent expansion with minimal infiltrates were observed on day 1 in 3 out of 17 dogs, day 2, 1/12; and day 4, 1/3, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Hearts with twisted atrioventricular connections: findings at MR imaging.

The "crisscross" heart and the heart with "superoinferior ventricles" are closely related congenital cardiac malformations that are characterized by twisted atrioventricular connections. The authors studied the morphologic characteristics of three hearts with twisted atrioventricular connections as seen on magnetic resonance (MR) images. The most important clue to the diagnosis was the distorted atrioventricular connections that were demonstrated on serial images. The axes of the atrioventricular connections through the atrioventricular valves were not parallel to each other. The presence of unusual recesses in the cardiac chambers, the angulated or curved configuration of the atrial and ventricular septa, and the unexpected great arterial relationship for the given combination of segmental connections supported the findings of twisted atrioventricular connections. MR imaging facilitated the precise morphologic diagnosis of these hearts.

Child, Preschool↗
PubMed1993

Early allograft function in canine single lung transplant.

An assessment of early graft function in canine single lung transplant recipients was made by analysing early postoperative radiographic progression, lung perfusion, bronchial patency and bronchial anastomotic wound healing and histopathology of the allografted lung. Eighteen mongrel dogs weighing 15kg on average were used. Donor lung bloc with a generous atrial cuff, the pulmonary artery and left bronchus were taken and flushed with Euro-Collins solution which implanted in the pneumonectomized recipient dog. Anastomosis was done with the atrium, pulmonary artery and bronchus in that order. To assess an early graft function, a protocol for a grading system was designed into the chest roentgenogram, lung perfusion scan, bronchial patency and histopathologic progression of the bronchial anastomosis and allografted lung (Table 1). The results were obtained as follows: Radiographically, clear to infiltrate was seen in 67% (8/12), 33% (5/15), 30% (3/10) and 33% (2/6) on postoperative day 0, 1, 2 and 3 respectively. Lobar to total opacification was 33% (4/12), 67% (10/15), 70% (7/10) and 67% (4/6) on days 0 to 3 (Table 2). Perfusion scan showed normal to mild defect in 43% (3/7) and moderate to severe defect in 57% (4/7) on day 0 and 100% (5/5) on day 2 (Table 3). The bronchial anastomotic site showed patent to mild stenosis in 100% (8/8) on day 0 and mild stenosis in 2/2 on day 9 bronchofiberscopically, and showed normal wound healing in 38% (3/8), cellular infiltration in 38% (3/8) and infarction in 25% (2/8) up to day 9 postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

MR anatomy of ventricular septal defect in double-outlet right ventricle with situs solitus and atrioventricular concordance.

Surgical treatment of patients with double-outlet right ventricle (DORV) depends on the spatial relation between the associated ventricular septal defect (VSD) and the arterial valves. This study was performed to refine the magnetic resonance (MR) imaging characteristics of VSD in DORV. Ten patients with DORV underwent MR imaging. Coronal, transverse, and oblique images were obtained with an electrocardiographic-gated multiple-section spin-echo technique. The transverse plane was the most valuable in defining the spatial relation of the VSD to the arterial valves. The site of fusion of the outlet septum with the VSD margin was diagnostically the most important feature in differentiating subaortic from subpulmonary VSD. The outlet septum fused with the anterior margin in subaortic VSD and the posterior margin in subpulmonary VSD; it was absent in doubly committed VSD. This study suggests that MR imaging can demonstrate the pertinent features of VSD and may be an indispensable adjunct to echocardiography in the preoperative evaluation of patients with DORV.

Angiocardiography↗