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Biomedical subjects

M F Chen

Publications and source records attributed to M F Chen.

At least 55 records · Page 3Linked to original sources
PubMed2000

Video-assisted endoscopic thyroidectomy.

BACKGROUND: Several experimental and clinical reports concerning endoscopic parathyroid surgery have appeared. However, reports concerning minimally invasive surgery for thyroid remains rare. Herein we present a new method, called video-assisted endoscopic thyroidectomy (VAET), for the management of various benign thyroid diseases. METHODS: In all, 16 consecutive patients who underwent VAET for benign thyroid diseases were retrospectively studied. The study group included nodular hyperplasia in 8 patients, follicular adenoma in 6, and Hurthle's tumor and simple cyst in 1 each. A 2 to 3 cm transverse incision was made on the suprasternal notch. The wound was deepened to expose the underlying trachea from which the plane of the thyroid fascia was accessed directly, and the working space was established with lifting method using conventional instrument. All surgical procedures could be manipulated and monitored under laparoscopy without gas insufflation. The ultrasonically activated scalpel was the principal instrument used for VAET. RESULTS: All 16 patients underwent VAET successfully without conversion to open thyroidectomy. The surgical procedures included lobectomy in 13 and extirpation in 3. The operation time ranged from 28 minutes to 5 hours (mean 1 hour, 42 minutes). For the 5 most recent cases, lobectomy took an average of 2 hours, whereas extirpation less than 40 minutes. The tumor size ranged from 3.5 cm to 8.0 cm (mean 5.8 cm). There were no surgical complications. All patients but 1 were discharged on postoperative day 2. During follow-up, all patients demonstrated euthyroid function and satisfactory cosmetic results. CONCLUSIONS: VAET emerges as a promising minimally invasive surgical technique replacing conventional thyroidectomy for benign thyroid diseases in selected cases, with the advantage of satisfactory cosmetic results.

Adenoma↗
PubMed2000

Biliary cutaneous stent insertion via T-tube tract by choledochoscopy.

BACKGROUND: Postoperative biliary ductal dilation and stent insertion are mandatory for managing complicated residual hepatolithiasis with intrahepatic strictures. Usually this procedure is performed under fluoroscopic guidance. Choledochoscopic examination is a routine procedure for residual hepatolithiasis. This is the first report of choledochoscopic biliary cutaneous stent insertion. METHODS: Fifty-three patients underwent biliary cutaneous stent insertion under postoperative choledochoscopic guidance. Of the 53 patients, 35 had strictured intrahepatic ducts, 6 a stenotic hilum, 9 a tortuous fistula tract and 3 a choledochoduodenocutaneous fistula. RESULTS: A total of 120 procedures have been performed in the 53 patients. Two thirds necessitated a repeated procedure. No major complication was found except 2 patients experienced mild abdominal pain after the procedure. Neither fluoroscopy nor contrast medium was used. CONCLUSIONS: Choledochoscopic guidance is effective for postoperative biliary cutaneous stent insertion. It has the advantage of being technically easy and is relatively safe.

Biliary Fistula↗
PubMed2000

Acute effects of urinary bladder distention on the coronary circulation in patients with early atherosclerosis.

OBJECTIVES: We sought to examine whether distention of the urinary bladder, a physiologic stimulus, could induce impaired coronary circulation in patients with early atherosclerosis. BACKGROUND: Distention of the urinary bladder reflexively causes an increase in sympathetic activity. The effect of such distention on the coronary circulation in patients with early atherosclerosis remains unknown. METHODS: To assess the effect of bladder distention on coronary dynamic forces, epicardial and microvascular responses were measured with an intracoronary Doppler flow wire in 40 patients with early atherosclerosis (<50% diameter stenosis). Patients were randomized into two groups according to whether they did not (group 1, n = 20) or did have (group 2, n = 20) pretreatment with an alpha1-adrenergic receptor blocker (oral doxazosin, 2 mg). Coronary flow velocity was monitored by quantitative coronary angiography at baseline, during urinary bladder distention and after intracoronary nitroglycerin injection. RESULTS: Bladder distention significantly decreased the coronary diameter in the stenotic segments (p<0.001), decreased coronary blood flow (p<0.001) and increased coronary resistance (p<0.001), as compared with baseline values, in group 1 patients. In group 2 patients with bladder distention, the angiographic variables did not show significant changes, as compared with baseline values. No significant differences were noted between the groups in the responses of the angiographic variables after nitroglycerin administration. CONCLUSIONS: The present study shows, for the first time, that urinary bladder distention caused vasoconstriction of coronary conduit and resistance vessels involved mechanisms related to alpha1 adrenoceptors. Pretreated administration of doxazosin reversed the changes toward baseline. Vasoconstriction during bladder distention can be relieved after nitroglycerin administration, suggesting an unchanged responsiveness of vascular smooth muscle cells to such distention.

Blood Flow Velocity↗
PubMed2000

Impact of concomitant hepatolithiasis on patients with peripheral cholangiocarcinoma.

The association of hepatolithiasis (HL) and peripheral cholangiocarcinoma (PCC) has been well recognized. However, information concerning the impact of hepatolithiasis on patients with peripheral cholangiocarcinoma is sparse and therefore difficult to assess. A total of 162 consecutive patients with histologically proven peripheral cholangiocarcinoma were treated surgically at Chang-Gung Memorial Hospital between 1977 and 1994. Among them, 106 patients (65.4%) had associated hepatolithiasis (PCC + HL group), and the remaining 56 patients (34.6%) did not (the PCC - HL group). The differences in demographics, symptomatology, laboratory data, tumor staging, histological pattern, resectability rates, and long-term survival of these two groups were compared. The male to female ratio was 0.7 in the PCC + HL group and 1.3 in the PCC - HL group (P < 0.05). Two thirds of the PCC + HL group presented with acute cholangitis, whereas two thirds of the PCC - HL group presented with hepatomegaly (P < 0.01). Those patients in the PCC + HL group were in earlier stages than those of the PCC - HL group at the time of the initial diagnosis (P < 0.05). The resectability rate for the PCC + HL group was 31.1% and for the PCC - HL group, 26.8% (P > 0.05). Surgical mortality rates were 3.8% in the PCC + HL group and 3.6% in the PCC - HL group (P > 0.05). The morbidity rate was much higher in the PCC + HL group than in the PCC - HL group (P < 0.01). The 1-, 3-, and 5-year survival rates were 35.5%, 20.5%, and 16.5% in the PCC + HL group and 27.2%, 8.8%, and 7.8% in the PCC - HL group (P > 0.05). In conclusion, the presence of hepatolithiasis hindered an exact diagnosis of underlying cholangiocarcinoma preoperatively, precipitated biliary sepsis which affected resectability, and increased postoperative morbidity. Hepatolithiasis per se, however, did not influence the long-term survival.

Adult↗
PubMed2000

Hepatic resection for benign tumours of the liver.

The most frequent benign tumours of the liver include haemangioma, liver cell adenoma and focal nodular hyperplasia. Patients may undergo hepatic resection because of a preoperative diagnosis of malignancy or uncertainty in diagnosis despite an extensive work-up.

Adenoma, Liver Cell↗
PubMed2000

Effect of n-3 fatty acids on the composition and binding properties of lipoproteins in hypertriglyceridemic patients.

BACKGROUND: Treatment of hyperlipidemic patients with fish oil results in an increase in plasma LDL cholesterol despite a marked decrease in the LDL precursor, VLDL. OBJECTIVE: We studied the relation between VLDL composition and LDL concentrations. DESIGN: Fourteen hypertriglyceridemic patients were treated with encapsulated fish oil (containing 1.45 g eicosapentaenoic acid and 1. 55 g docosahexaenoic acid/d) for 4 wk. Venous blood samples were collected before and after treatment. Eleven normolipidemic subjects served as a control group. RESULTS: Fish oil effectively lowered plasma lipid and apolipoprotein (apo) E concentrations in the hypertriglyceridemic patients, whereas apo B concentrations increased. The lipid and apolipoprotein content of VLDL decreased, whereas LDL cholesterol and LDL apo B increased. Fractionation of VLDL by heparin-affinity chromatography showed that before treatment hypertriglyceridemic patients had more VLDL in the 0.05-mol NaCl/L subfraction and less in the 0.20-mol/L subfraction than did control subjects (P < 0.05), whereas the subfraction distribution pattern was normalized after fish-oil treatment. Nevertheless, plasma concentrations of the 0.05-mol NaCl/L subfraction were decreased and those of the 0.20-mol/L subfraction were increased in hypertriglyceridemic patients after fish-oil treatment (P < 0.05). Fish-oil treatment both enhanced VLDL binding and lowered LDL binding to fibroblasts. CONCLUSION: Treatment of hypertriglyceridemic patients with fish oil caused differential effects on VLDL subfractions and decreased LDL binding to fibroblast receptors, which may have contributed to the paradoxical increase in LDL-cholesterol concentrations.

Apolipoproteins B↗
PubMed2000

Effects of timing of diatrizoate (water-soluble contrast medium) administration on pancreatic microcirculatory derangement in cerulein pancreatitis in rats.

OBJECTIVE: We investigated whether the timing of administration of contrast medium after onset of acute pancreatitis is critical in determining the magnitude of microcirculatory derangement. METHODS: An acute pancreatitis model in male Sprague-Dawley rats (225-275 g) was established by continuous infusion of cerulein (15 mg/kg per hour). The mean arterial pressure was monitored continuously by means of a femoral artery catheter. Diatrizoate (Hypaque-76), a water-soluble contrast medium, was delivered through a femoral vein catheter at doses corresponding to those given to humans, either 1, 2, or 3 hours after pancreatitis induction. In vivo microscopy and laser-Doppler flowmetry were used to investigate microcirculatory derangement. The water contents of the pancreas and lung, the malondialdehyde levels of the pancreas, and the trypsinogen activation peptide levels in the serum were measured at the end of the experiment (8 hours after infusion of cerulein). RESULTS: Early administration of contrast medium (1 hour after pancreatitis induction) resulted in significantly greater changes in microcirculation and mean arterial pressure than did late administration (2 or 3 hours after pancreatitis induction). Rats given contrast medium 1 hour after induction also had highest pancreas and lung water contents, the highest pancreas malondialdehyde levels, and the highest serum trypsinogen activation peptide levels. CONCLUSION: These results show that a water soluble contrast medium that is often used for computed tomographic imaging of the pancreas can adversely affect the pancreatic microcirculatory parameters, such as tissue perfusion and leukocyte sticking, and hemodynamics in a cerulein-induced model of acute pancreatitis. Early administration seems to cause more severe derangement of the pancreatic microcirculation.

Acute Disease↗
PubMed2000

Blunt hepatic injury: minimal intervention is the policy of treatment.

BACKGROUND: Many publications recommend nonoperative treatment for stable blunt hepatic injury patients. Unstable hemodynamic status is the only indication for surgery. When operation is indicated, controversies exist regarding which operative procedure will be more beneficial to the patients. The purposes of this study are to compare the results of operative and nonoperative management of patients with blunt hepatic injuries and to identify the optimal surgical approach when surgery is indicated. METHODS: Different prospective protocols of treating adult blunt hepatic injuries were conducted. From 1992 to 1993 (group I), urgent surgery would be performed in the presence of hemoperitoneum. The policy shifted to aggressive nonoperative approach between 1996 and 1997 (group II). The patients from each period were divided into three subgroups. Group A included the patients who received nonoperative treatment in either period. Group B consisted of the patients who received surgery in the first period and nonoperative management in the second period. Group C included the patients who were operated on in either group. Comparisons were made between matched groups. RESULTS: Groups IA and IIA patients had minor injuries and could be successfully treated nonoperatively. The results of groups IB and IIB were similar concerning hospital stay, morbidity, and mortality. Transfusion requirements of group IIB patients were significantly higher (2.2 vs. 1.1 units,p = 0.01) than those of group IB. However, 25 (58%) celiotomies of group IB patients were nontherapeutic. When surgery was indicated, group IC patients had significantly higher liver-related mortality (14 of 49 vs. 3 of 55, p = 0.002). Anatomic resection was performed more frequently in that period. CONCLUSION: Nonoperative treatment significantly decreased the rate of nontherapeutic laparotomy but carried the risks of higher transfusion requirements and delaying operation. When surgery was indicated, the policy of minimal intervention positively affected the patients' outcomes. The goal of surgery should be hemorrhage control rather than resection of the injured liver tissues.

Adult↗
PubMed2000

Factors determining operative mortality of grade V blunt hepatic trauma.

BACKGROUND: Despite recent advances in the management of severe hepatic injuries, the operative mortality rate of grade V hepatic injuries still ranges from 67% to 80%. Grade V hepatic injuries involving the retrohepatic cava or main hepatic veins are almost always lethal, especially those from blunt trauma. The purpose of this study is to understand the risk factors determining operative mortality in grade V blunt hepatic trauma, and to try to improve the surgical management of these injuries. METHODS: A retrospective study was conducted at a medical center that offers services including primary, secondary, and tertiary care. Forty-four patients with grade V blunt hepatic injuries were treated during a 6-year period from January 1, 1991, to December 31, 1996. The operative mortality was compared by a multivariate analysis. RESULTS: Forty-four patients with grade V blunt hepatic injuries were identified. Seven patients had only parenchymal injuries, and the others had vascular and associated parenchymal injuries. Venorrhaphy was used in 37 patients; 29 were treated using a nonshunting approach, and 8 with an atriocaval shunt. The overall mortality rate was 68% (30 of 44), and liver-related mortality was 50% (22 of 44). Univariate analysis revealed that the significant variables affecting operative mortality were initial systolic blood pressure, initial base deficit, the Glasgow Coma Scale, injury type, number of resected segments, and total intraoperative blood loss. Based on forward stepping logistic regression analysis, patients with an initial base deficit of -6 mmol/L or less (relative risk = 17.3), and a total intraoperative blood loss of 5,000 mL or more (relative risk = 23.5) would, significantly, encounter a worsening prognosis. CONCLUSIONS: Initial base deficit and total intraoperative blood loss were the significant factors that determined operative mortality after grade V blunt hepatic trauma. We suggest that prompt resuscitation and expeditious and appropriate surgical management, to control operative blood loss, is the only way to reduce operative mortality in patients with grade V blunt hepatic trauma.

Adolescent↗
PubMed2000

Classification and treatment of pooling of contrast material on computed tomographic scan of blunt hepatic trauma.

BACKGROUND: Pooling of contrast material on computed tomographic (CT) scan represents free extravasation of blood as a result of active bleeding. For patients with blunt hepatic injury, aggressive management such as angiography or celiotomy is usually indicated if this sign is detected. The purposes of this study were to further categorize this CT scan finding and to correlate its characteristics with clinical outcomes. This CT scan classification might be helpful for the selection of appropriate management. METHODS: During a 42-month period, 276 patients with blunt hepatic injury were treated. Two hundred twelve of them were hemodynamically stable after initial resuscitation and underwent abdominal CT scan examination. Pooling of contrast material was detected on the CT scans of 15 patients. The CT scans and medical records were reviewed. Special attention was paid to the presence, location, and character of the extravasated contrast material. RESULTS: The finding of pooling of contrast material on CT scan was categorized into three types according to its location and character. Type I showed extravasation and pooling of contrast material in the peritoneal cavity (six patients). All patients with type I CT scan findings became hemodynamically unstable soon after CT scan examination and required emergent laparotomy. Type II findings showed simultaneous presence of hemoperitoneum and intraparenchymal contrast material pooling (six patients). Four patients with type II CT scan findings required laparotomy for hemostasis. Type III findings showed intraparenchymal contrast material pooling without hemoperitoneum (three patients). All patients with type III CT scan signs remained hemodynamically stable. CONCLUSION: With the use of a high-speed spiral CT scanner, it is possible to predict the necessity of operative management or angiography for patients with blunt hepatic injury before deterioration of hemodynamic status. The presence of pooling of contrast material within the peritoneal cavity indicates active and massive bleeding. Patients with this CT scan finding show rapid deterioration of hemodynamic status. Most of these patients might require emergent surgery. Pooling of contrast material in a ruptured hepatic parenchyma indicates active bleeding. Close monitoring and emergent angiography should be performed. Deterioration of hemodynamic status in these patients usually requires prompt surgical intervention. Intraparenchymal pooling of contrast material with unruptured liver capsule often indicates a self-limited hemorrhage. Patients with this CT scan finding have a high possibility of successful nonoperative treatment.

Adolescent↗
PubMed2000

Exercise shifts the platelet aggregation modulatory role from native to mildly oxidized low-density lipoprotein.

PURPOSE: The role of low-density lipoprotein (LDL) lipid peroxides in strenuous exercise-induced changes in platelet function was studied in 30 patients (male/female = 22/8) aged 30-62 yr (mean +/- SD = 508). METHODS: All subjects were subjected to a treadmill exercise test, using the standard Bruce protocol. Blood samples were collected pre-, peak, and 10 min postexercise to assess hematological and biochemical parameters and platelet aggregation. Ex vivo whole blood platelet aggregation during treadmill exercise was assessed in 10 subjects by adding mildly oxidized LDL. RESULTS: Preexercise, a correlation existed between plasma thromboxane (TX) levels and plasma LDL cholesterol or beta-thromboglobulin (beta-TG) levels (r = 0.48, P < 0.05: r = 0.47, P < 0.05, respectively), whereas, at peak exercise, TX and beta-TG levels increased, but no correlation was seen. At peak exercise, platelets showed hyperaggregability in terms of maximal amplitude and reaction slope (P < 0.001 and P < 0.01, respectively). In contrast to the increase in plasma lipid peroxide levels seen during peak exercise (P < 0.05), LDL lipid peroxides decreased during exercise, this decrease reaching a statistical significance at 10 min postexercise (P < 0.05). In addition, the ex vivo addition of mildly oxidized LDL (10 mg protein x L(-1)) to peak exercise blood resulted in a significant attenuation of platelet aggregation and a decrease in TX release. At 10 min postexercise, a correlation was seen between LDL lipid peroxides and TX levels (r = 0.78, P < 0.001) or beta-TG levels (r = 0.68, P < 0.005). CONCLUSION: These results suggest that LDL lipid peroxides play a role in modulating and attenuating platelet aggregation during strenuous exercise.

Adult↗
PubMed2000

Malignant perihilar biliary obstruction: magnetic resonance cholangiopancreatographic findings.

OBJECTIVE: We studied the efficacy of magnetic resonance cholangiopancreatography (MRCP) in the evaluation of malignant perihilar biliary obstructions, with reference to endoscopic retrograde cholangiopancreatography (ERCP). METHODS: A total of 40 patients with malignant perihilar biliary obstructions, who underwent both MRCP (Magnetom Vision; Siemens, Erlangen, Germany; projection technique and multislice plus maximum intensity projection) and ERCP examinations, were studied. The study group included hilar cholangiocarcinoma (Klatskin tumor) in 26 patients, icteric hepatocellular carcinoma in four patients, gallbladder carcinoma in five patients, and metastasis from other than hepatobiliary origin in five patients. Axial and coronal magnetic resonance (MR) images were added simultaneously to the MRCP. The mean serum bilirubin level on admission was 11.5 mg/ml (range, 2.8-28.5 mg/ml). The presence and extent of malignant biliary obstruction were determined with both MRCP and ERCP following the known criteria: an abrupt and irregular character of a distal narrow segment, a proportionally dilated biliary tree proximally, and an irregularly shaped intraluminal filling defect. The efficacy of the MRCP examination in detecting the presence of biliary obstruction, its anatomical extent, and the underlying cause, respectively, was compared to that of ERCP. RESULTS: MRCP examination was successfully performed on all patients, whereas ERCP examination was unsuccessful in two patients. Both MRCP and ERCP were very effective in detecting the presence of biliary obstructions (40 of 40 vs. 38 of 38, p = 1.0). MRCP was superior in its investigation of anatomical extent (34 of 40 vs. 24 of 38, p = 0.015) and the cause of the jaundice (31 of 40 vs. 22 of 38, p = 0.023) compared to ERCP. Specifically, the performance of MRCP is promising for the interpretation of cholangiocarcinoma (22 of 26) and gallbladder carcinoma (five of five), but is relatively ineffective for the interpretation of icteric HCC (two of four) and metastasis (two of five). CONCLUSION: MRCP represented an ideal noninvasive diagnostic tool for the evaluation of malignant perihilar biliary obstructions with reference to ERCP.

Bile Duct Neoplasms↗
PubMed2000

Female sex hormones modulate the function of LPS-treated macrophages.

PROBLEM: To study the effects of estradiol (E2) or progesterone on macrophage function in the presence of lipopolysaccharide (LPS). METHOD OF STUDY: Male rat peritoneal macrophages were treated in vitro with 0.1 microg/mL of LPS and E2 or progesterone. RESULTS: At 10(-2) ng/mL, E2 significantly (P < 0.05; n = 6) enhanced tumor necrosis factor (TNF) release by LPS-treated macrophages. TNF release was significantly (P < 0.05; n = 6) inhibited by 10(2) ng/mL or 10(3) ng/mL of E2 and by progesterone at less than 10(-3) ng/mL or greater than 10(-1) ng/mL. E2 (10(-4) and 10 ng/mL) and progesterone (10(-6)-10(-4) ng/mL and 10(2) ng/mL) each significantly (P < 0.05, n = 8) enhanced H2O2 release by LPS-treated macrophages. E2 ( < 10(-2) and > 10 ng/mL) and progesterone (10(-7)-10(4) ng/mL) each significantly inhibited (P< 0.05; n = 6) NO2- release by LPS-treated macrophages. CONCLUSIONS: Exposure to LPS tended to diminish the effects of E2 and to enhance the effects of progesterone on the parameters determined here. Such LPS-associated alterations in the dose-response profile of macrophages to female sex hormones may contribute to gender-related differences in the immune response under normal and pathological conditions.

Animals↗
PubMed2000

Therapeutic effect of sheng-ji-san on pressure ulcers.

In the present study, the effectiveness of sheng-ji-san (SJS) in promoting the healing of pressure ulcers was evaluated. Thirty-two patients with pressure ulcers were divided into two groups. The treated group received routine medical care combined with SJS treatment and the control group received only routine medical care. After three weeks, the treated group showed a significant reduction in both surface area and depth grade, while the control group showed no significant change. The reduction ratio of the surface area of the ulcer and the effectiveness ratio for the treated group were significantly higher than for the control group. Multiple Linear Regression Analysis revealed that only the SJS treatment was significantly associated with the reduction of surface area and that the use of SJS could independently explain the observed high effectiveness ratio and a relatively high Odds Ratio of 9.539. These results indicate that SJS is effective in promoting the healing of pressure ulcers and should be considered as an adjuvant to routine therapy.

Aged↗
PubMed2000

Distension of urinary bladder induces exaggerated coronary constriction in smokers with early atherosclerosis.

Distension of the urinary bladder causes an increase in efferent sympathetic activity, which can precipitate myocardial ischemia. Smoking has been shown to modulate activities of afferent nerves from the distended urinary bladder and to impair endothelial function in response to sympathetic activation. To assess the effect of bladder distension on coronary dynamics in smokers, we measured epicardial and microvascular responses in 24 patients with early atherosclerosis (< 50% diameter stenosis). Patients were classified into habitual smokers (group 1, n = 14) and nonsmokers (group 2, n = 10). Habitual smokers were randomized into two subgroups on the basis of the use of doxazosin, as follows: subgroup 1A (n = 7), without administration of doxazosin before catheterization; subgroup 1B (n = 7), with dosing doxazosin. In response to bladder distension (mean intravesical pressure 21.5 mmHg), bladder distension significantly decreased coronary diameter at the stenotic segments, coronary blood flow, and increased coronary resistance compared with baseline values, in subgroup 1A patients. In subgroup 1B patients during bladder distension, coronary diameter, coronary blood flow, and coronary resistance did not show significant changes compared with baseline values. There were significant differences of coronary diameter at the stenotic segments, coronary blood flow, and of changes of coronary vascular resistance between subgroup 1A and group 2 during bladder distension, despite similar changes in rate-pressure product. The present study showed that urinary bladder distension caused an abnormal vasomotor response of epicardial vasoconstriction and a concomitant increased coronary resistance, which leads to reduction in coronary blood flow in patients with early atherosclerosis. Smoking may further impair the response, implying that smoking has exaggerated response to sympathetic stimulation of conduit and resistance vessels. The abnormal response was abolished by pretreated administration of doxazosin, suggesting that the involved mechanisms are related to alpha(1)-adrenoceptors.

Aged↗
PubMed2000

Integrated backscatter for quantification and risk stratification of blood stagnation in left atrial appendages of patients with rheumatic mitral stenosis.

This study was designed to quantify the blood stagnation in left atrial appendages (LAA) of patients with rheumatic mitral stenosis, and to stratify the risk of spontaneous echo contrast (SEC) for thrombus formation. A total of 45 patients were enrolled in this study. Thirty of the 45 patients had rheumatic mitral stenosis. All the above patients were evaluated for LAA contractility by transesophageal echocardiography. Acoustic density of the stagnant blood was assessed using the integrated backscatter (IBS) mode. Multivariate linear regression analysis showed that the significant independent variables determining relative IBS in LAA were the mitral valve area (p = 0.02) and the atrial fibrillation rhythm (p = 0.0003). In patients with mitral stenosis, the IBS in LAA correlated well with the presence of thrombus (p = 0.004) and SEC (p = 0.002). Using the relative IBS in LAA with 6.8 dB as the cutoff value, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of SEC formation in LAA was 83, 86, 95, 60 and 83%, respectively. Using the relative IBS in LAA with 10.0 dB as the cutoff value, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and accuracy of SEC with thrombus formation in LAA was 80, 80, 67, 89 and 80%, respectively. In conclusion, the blood stasis in LAA can be objectively quantified using IBS. Utilizing different cutoff values, the acoustic densitometry in LAA enables identification of stagnant blood which represents a risk for the development of either SEC only or SEC with thrombus formation.

Adolescent↗