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Tzong-Luen Wang

Publications and source records attributed to Tzong-Luen Wang.

13 recordsLinked to original sources
PubMed2007

Silent myocardial ischemia in coronary artery disease patients under aspirin therapy presenting with upper gastrointestinal hemorrhage.

AIM: To identify the risk factors for myocardial ischemia in patients undergoing aspirin therapy for coronary artery disease (CAD) presenting with upper gastrointestinal hemorrhage and to ascertain the impacts on mortality and length of hospital stay. METHODS: Adults with CAD under aspirin therapy (100 mg once daily) presenting to the emergency department with upper gastrointestinal hemorrhage were retrospectively recruited and divided into group A (ischemia) and group B (non-ischemia). Charts were reviewed for various demographic, laboratory and outcome data. Electrocardiograms were interpreted blindly by a senior cardiologist. RESULTS: A total of 152 patients, 72.4% men and 27.6% women, were analyzed. Of these, 31 patients had ischemia and were placed in group A and 121 patients did not have ischemia and were in group B. Independent multivariate predictors of myocardial ischemia were history of triple vessel disease (odds ratio [OR], 9.24; 95% confidence interval [CI], 2.00-42.72), lower diastolic blood pressure (OR, 1.09; 95% CI, 1.02-1.16), lower hematocrit (OR, 1.41; 95% CI, 1.16-1.70), and higher blood urea nitrogen (OR, 0.94; 95% CI, 0.89-0.98). Patients with myocardial ischemia had significantly longer hospital length of stay (8.7 +/- 4.0 days vs 5.4 +/- 1.7 days; P < 0.001) and higher in-hospital mortality (16.1%vs 2.5%; P < 0.01) than did those without myocardial ischemia. CONCLUSION: Myocardial ischemia is a relatively common complication in CAD patients under aspirin therapy presenting with upper gastrointestinal hemorrhage. A history of CAD with triple vessel disease, higher blood urea nitrogen, lower diastolic blood pressure and lower hematocrit may help identify patients who are at increased risk of myocardial ischemia, which tends to be associated with higher in-hospital mortality and increased length of hospital stay.

Aged↗
PubMed2005

Low plasma vasopressin/norepinephrine ratio predicts septic shock.

To evaluate if low plasma vasopressin and high norepinephrine concentrations predict grave prognosis of sepsis, a prospective sample of consecutive patients visiting the emergency department of a university teaching hospital who met the American College of Chest Physicians criteria of sepsis or severe sepsis was enrolled. Besides septic workup, we measured serum vasopressin and norepinephrine concentrations to correlate the impending outcome. One hundred eighty-two patients aged 27 to 99 years met the inclusive criteria and were classified as those with septic shock (n = 72), severe sepsis (n = 56), and those with sepsis only (n = 54) according to the outcome within 6 hours. Thirty healthy subjects were included as control. The plasma vasopressin level at baseline was significantly lower for those who finally developed septic shock (septic shock group, 3.6 +/- 2.5 pg/mL; 95% confidence interval [CI], 3.0-4.2 pg/mL; severe sepsis group, 21.8 +/- 4.1 pg/mL, 95% CI, 20.7-22.9 pg/mL; sepsis group, 10.6 +/- 6.5 pg/mL, 95% CI, 8.8-12.4 pg/mL, P < .001), whereas the norepinephrine level was highest for the same group (septic shock group, 3650 +/- 980 pg/mL, 95% CI, 3420-3880 pg/mL; severe sepsis group, 3600 +/- 1000 pg/mL, 95% CI, 3330-3870 pg/mL; sepsis group, 1720 +/- 320 pg/mL, 95% CI, 1630-1810 pg/mL). The vasopressin/norepinephrine ratio was significantly lower for the patients with final diagnosis of septic shock (P < .001). The mean interval between the time of samples drawn and the time of the most severe occurring sequelae was 2.4 +/- 0.8 hours. Receiver operating characteristic analysis revealed that the vasopressin/norepinephrine ratio 1 x 10(-3) had a sensitivity of 97% (95% CI, 90%-99%) and a specificity of 85% (95% CI, 78%-91%) for detecting impending septic shock. Low serum vasopressin/norepinephrine ratio can predict impending septic shock.

Adult↗
PubMed2005

Somatostatin analogue mimics acute ischemic preconditioning in a rat model of myocardial infarction.

We tested the hypothesis that octreotide, a somatostatin analogue, can mimic ischemic preconditioning (PC) to provide cardioprotection against myocardial infarction. An ischemia-reperfusion model of adult Wistar rats was used. Infarct size was expressed as a percentage of the area at risk under different treatment protocols. Octreotide PC (35 microg/Kg 20 minutes before ischemia-reperfusion) significantly decreased infarct size (18 +/- 4%) versus control (60 +/- 7%). The somatostatin receptor antagonist cyclo-somatostatin (0.5 mg/Kg) could blunt the above cardioprotection. Administration of either chelerythrine (a protein kinase C inhibitor, 2 mg/Kg) or genistein (a tyrosine kinase inhibitor, 5 mg/Kg) could also block octreotide PC (54 +/- 7% and 58 +/- 6%, respectively). Pretreatment with the mitochondrial ATP-sensitive potassium channel antagonist 5-hydroxydecanoic acid (5-HD) and the sarcolemmal ATP-sensitive potassium channel antagonist glibenclamide could abolish the effects of octreotide PC (54 +/- 6% and 52 +/- 6%). Chelerythrine, however, had no effect on octreotide PC. In conclusion, the present study demonstrates that octreotide can mimic ischemic PC to reduce infarct size. Acute effects of octreotide PC involve the activation of protein kinase C, tyrosine kinase C, and mitochondrial ATP-sensitive potassium channels, but not systemic IGF-I activation.

Animals↗
PubMed2004

Evolution of plasma D-dimer and fibrinogen in witnessed onset of paroxysmal atrial fibrillation.

BACKGROUND: Although increased D-dimer and fibrinogen have been proved to be related with atrial fibrillation (AF), their evolution in the course of time remains unclear. METHODS: To elucidate the evolution of plasma D-dimer and fibrinogen in AF of different duration. 56 patients (group A) of 3,524 patients in whom the onset of AF had been witnessed in a chest pain clinic were enrolled for study. Plasma D-dimer and fibrinogen concentrations were checked within 30 min after the onset of AF and followed up as scheduled. Another 50 patients (group B) with chronic AF underwent the same protocol and served as controls. RESULTS: In group A, the D-dimer levels reached a plateau at the 18th hour (382 +/- 52 vs. 840 +/- 280 ng/ml, p < 0.001 by ANOVA) and the fibrinogen level increased gradually from 4.1 +/- 0.6 g/ml at baseline to 6.1 +/- 0.9 g/ml at the 48th hour (p < 0.001). No subjects had evidence of intra-cardiac thrombi by transesophageal echocardiography. There were significant differences in plasma D-dimer and fibrinogen levels between the two groups at each measurement. At the cut- off value of 500 ng/ml, plasma D-dimer had a sensitivity of 100%, a specificity of 93% in defining AF lasting for less than 12 h. The positive and negative predictive values were 52% and 100%, respectively. Plasma D-dimer increased above the normal range prior to the 12th hour after the onset of AF. CONCLUSION: The observations support its use as a screening tool for identifying patients with short duration AF capable of being safely converted.

Acute Disease↗
PubMed2004

Establishing a clinical decision rule of severe acute respiratory syndrome at the emergency department.

STUDY OBJECTIVE: In the absence of reliable rapid confirmatory tests during severe acute respiratory syndrome (SARS) endemics, we designed a 2-phase cohort study to establish a scoring system for SARS and to evaluate whether it could improve the sensitivity and specificity of the World Health Organization (WHO) criteria. METHODS: According to the clinical characteristics and initial laboratory findings of 175 suspected cases defined by the WHO criteria (20 confirmed as cases of SARS) in 3 university teaching hospitals in Taipei between March 1 and April 20, 2003, the scoring system for SARS was designed by multivariate analysis and stepwise logistic regression as the simple arithmetic sum of point values assigned to 7 parameters. We thereafter applied the scoring system for SARS to the consecutive 232 patients (the validation group) who met the WHO criteria of suspected cases from April 21 to May 22, 2003. Final diagnosis of SARS was determined by the results of real-time polymerase chain reaction and paired serum. RESULTS: The scoring system for SARS was defined as radiographic findings of multilobar or bilateral infiltrates (3 points), sputum monocyte predominance (3 points), lymphocytopenia (2 points), history of exposure (1 point), lactate dehydrogenase more than 450 U/L (1 point), C-reactive protein more than 5.0 mg/dL (1 point), and activated partial prothrombin time more than 40 seconds (1 point). Of the validation group, 60 patients (group A) were confirmed as having cases of SARS, and the other 172 (group B) patients tested negative for SARS. The total points of the scoring system for SARS at initial presentation were significantly higher in the SARS group (median 9; range 6 to 11) than in the non-SARS group (median 4; range 3 to 7; P<.001). At the cutoff value of 6 points, the sensitivity and specificity of the scoring system for SARS in diagnosing SARS were 100% and 93%, respectively. The positive and negative predictive values of the scoring system for SARS were 83% and 100%, respectively. CONCLUSION: The scoring system for SARS can provide a rapid and reliable clinical decision to help emergency physicians detect cases of SARS more accurately in the endemic area.

Blood Cell Count↗
PubMed2004

Role of tissue oxygen saturation monitoring in diagnosing necrotizing fasciitis of the lower limbs.

STUDY OBJECTIVE: We determine the utility of tissue oxygen saturation monitoring in diagnosing necrotizing fasciitis of the lower extremities. METHODS: We prospectively studied patients who met the criteria of soft tissue infection throughout the lower extremities by tissue oxygen saturation monitoring (with near-infrared spectroscopy) over the middle third of possible involved areas. Cases with evidence of chronic venous stasis, peripheral vascular disease, shock, and systemic hypoxia were excluded. Biceps and contralateral unaffected leg areas were measured as references. The tissue oxygen saturation reading for each area was compared with those finally diagnosed as necrotizing fasciitis and those with only simple soft tissue infection. The tissue oxygen saturation reading was presented as mean+/-SD. Receiver operating characteristic (ROC) curves were used to determine a cutoff value of tissue oxygen saturation reading for early diagnosis of necrotizing fasciitis. RESULTS: Two hundred thirty-four consecutive patients were enrolled. Nineteen patients (group N) were confirmed to have necrotizing fasciitis, whereas the remaining 215 patients (group C) had only cellulitis. The tissue oxygen saturation reading measured over the biceps muscle was 86%+/-11% in group N and 85%+/-12% in group C. In group N, the leg with necrotizing fasciitis had a tissue oxygen saturation reading of 52%+/-18% throughout the involved site, whereas the tissue oxygen saturation reading measured in the comparative values found in group C was 84%+/-7% (difference 95% confidence interval [CI] 22% to 29%). After fasciotomy, the tissue oxygen saturation reading of the leg with necrotizing fasciitis returned to 82%+/-17% (95% CI 23% to 28% compared with prefasciotomy value) in group N. At the cutoff value of a tissue oxygen saturation reading less than 70% (area under the curve 0.883; 95% CI 0.817 to 0.949) defined by ROC curve, the test revealed a sensitivity of 100% (95% CI 82% to 100%), a specificity of 97% (95% CI 94% to 99%), and an accuracy of 97% (95% CI 95% to 99%). CONCLUSION: The low tissue oxygen saturation reading values measured by near-infrared spectroscopy throughout the involved areas of the lower extremities are of value in identifying necrotizing fasciitis. This method may offer a reliable noninvasive method of assessing lower extremities at risk for necrotizing fasciitis, at least for a selected patient population.

Adult↗
PubMed2004

Angiotensin II signals mechanical stretch-induced cardiac matrix metalloproteinase expression via JAK-STAT pathway.

BACKGROUND: Mechanical stress induces many pathophysiological effects in cardiomyocytes. The objective of this study was to test the hypothesis that angiotensin II is a potential mediator of stretch-induced activation of matrix metalloproteinases (MMP). METHODS: Neonatal rat cardiomyocytes grown on a flexible membrane were cyclically stretched achieving up to 20% elongation at 60 cycles/min (using a vacuum). We explored the signaling pathways involved in cyclical stretch-induced expression of MMP-14 and MMP-2. RESULTS: Cyclical mechanical stretch significantly increased mRNA expression and protein synthesis for MMP-14 and MMP-2 from the 6(th) to 24(th) h. The increase in MMP-14 and -2 proteins after stretch was completely blocked after the pretreatment with losartan (an angiotensin II AT1 receptor antagonist, 200 nM) and AG-490 (a Janus kinase 2 tyrosine kinase inhibitor, 100 nM) but not with PD 98059 (an inhibitor of p42/p44 mitogen-activated protein kinase, 50 microM) or wortmannin (a phosphatidylinositol 3-kinase, 30 nM). By zymography, MMP-2 activity was increased by cyclical stretch that was significantly attenuated by losartan and AG-490. The mechanical strain also increased the immunohistochemical labeling of MMP-14 and -2 that was attenuated by adding losartan. Cyclical stretch increased the expression of STAT-1 that was abolished by pretreating with losartan or AG-490 (50 microM and 100 microM). CONCLUSION: These findings indicate that cyclical stretch induces MMP-14 and -2 expression in neonatal rat cardiomyocytes and that the induction is mediated by the angiotensin II-JAK-STAT1 pathway.

Angiotensin II↗
PubMed2003

Stratification of adverse outcomes by preoperative risk factors in coronary artery bypass graft patients: an artificial neural network prediction model.

We constructed and internally validated an artificial neural network (ANN) model for prediction of in-hospital major adverse outcomes (defined as death, cardiac arrest, coma, renal failure, cerebrovascular accident, reinfarction, or prolonged mechanical ventilation) in patients who received "on-pump" coronary artery bypass grafting (CABG) surgery. We retrospectively analyzed a 5-year CABG surgery database with a final study population of 563 patients. Predictive variables were limited to information available before the procedure, and outcome variables were represented only by events that occurred postoperatively. The ANN's ability to discriminate outcomes was assessed using receiver-operating characteristic (ROC) analysis and the results were compared with a multivariate logistic regression (LR) model and the QMMI risk score (RS) model. A major adverse outcome occurred in 12.3% of all patients and 18 predictive variables were identified by the ANN model. Pairwise comparison showed that the ANN model significantly outperformed the RS model (AUC = 0.886 vs.0.752, p = 0.043). However, the other two pairs, ANN vs. LR models (AUC = 0.886 vs. 0.807, p = 0.076) and LR vs. RS models (AUC = 0.807 vs. 0.752, p = 0.453) performed similarly well. ANNs tend to outperform regression models and might be a useful screening tool to stratify CABG candidates preoperatively into high-risk and low-risk groups.

Cardiopulmonary Bypass↗