Mei-Han Wu

Quantitative Analysis of Quantity and Distribution of Epicardial Adipose Tissue Surrounding the Left Atrium in Patients With Atrial Fibrillation and Effect of Recurrence After Ablation

Epicardial adipose tissue (EAT) contains ganglionated plexuses and adipocytes that can affect the pathogenesis of atrial fibrillation (AF). The aim of this study was to quantify the EAT surrounding the left atrium (LA) and correlate it with occurrence of AF and outcome after catheter ablation. EAT was evaluated using 64-slice multidetector computed tomography in 68 patients with AF and 34 controls. EAT volume was acquired by semiautomatically tracing axial images from the pulmonary artery to the coronary sinus. Topographic distribution of EAT was assessed by dividing the periatrial space into 8 equal regions. EAT volume significantly increased in patients with AF than in controls (29.9 ± 12.1 vs 20.2 ± 6.5 cm(3), p <0.001). Most EAT was located in regions (1) within the superior vena cava, right pulmonary artery, and right-sided roof of the LA (29.8%), (2) within the aortic root, pulmonary trunk, and left atrial appendage (26.5%), and (3) between the left inferior pulmonary vein and left atrioventricular groove (18.1%). Baseline variables were analyzed in patients with (n = 24) and without (n = 44) AF recurrence after ablation. The recurrent group showed significantly increased EAT (35.2 ± 12.5 vs 26.8 ± 11.1 cm(3), p = 0.007). Multivariate analysis revealed that EAT was an independent predictor of AF recurrence after ablation (p = 0.038). In conclusion, EAT of LA was increased in patients with AF. Large clusters of EAT were observed adjacent to the anterior roof, left atrial appendage, and lateral mitral isthmus. Abundance of EAT was independently related to AF recurrence after ablation.

The impact of catheter ablation on the dynamic function of the left atrium in patients with atrial fibrillation: insights from four-dimensional computed tomographic images.

Functional Evaluation of the LA by Dynamic CT.  Introduction: Elucidating the functional properties and remodeling process of the entire left atrium (LA) is important not only for offering the mechanistic insight into atrial fibrillation (AF) but also for assessing the effectiveness of catheter ablation.

Electron Beam Computed Tomography Evidence of Aortic Calcification as an Independent Determinant of Coronary Artery Calcification

Background: Imaging of the aorta has received less attention than imaging of the coronary beds, despite the possible link between aortic and coronary artery disease (CAD). Electron beam computed tomography (EBCT) with 100 ms scanning speed can eliminate pulsation‐related motion artifacts. The goals of this study were to evaluate EBCT‐detected subclinical atherosclerosis over the whole aorta as in routine abdominal and thoracic CT scans and analyze whether or not the measurements of aortic calcification (AC) can independently predict the presence of coronary artery calcification (CAC), which is a surrogate marker of CAD. Methods: A consecutive series of 196 adults (male:female, 127:69; mean age, 65.9±10.5 years) were enrolled for EBCT examinations of the coronary arteries and whole aorta. CAC and AC were calculated by the Agatston method. Major cardiovascular risk factors were also recorded. Results: The greatest amount of AC was seen at the abdominal aorta, followed by the descending aortic arch, thoracic aorta, and ascending aorta. Total AC was significantly correlated with CAC (r=0.51, p< 0.001). After adjustment for major cardiovascular risk factors of age, gender, diabetes, hypertension, hypercholesterolemia, and family history, the three independent significant determinants of CAC were abdominal AC, thoracic descending AC, and male gender (model r2 = 0.495, p<0.001). For receiver operating characteristic analysis in predicting the presence of CAC, the threshold of descending AC was 11, with 68.3% sensitivity and 75.0% specificity. The optimal threshold of abdominal AC was 123, with 74.1% sensitivity and 67.9% specificity. Conclusion: AC values in different portions of the aorta are independent predictors for the presence of CAC.

Myocardial Bridging in Taiwan: Depiction by Multidetector Computed Tomography Coronary Angiography

BACKGROUND/PURPOSE Myocardial bridging (MB) is a condition in which a segment of the major epicardial coronary artery is tunneled within and surrounded by the myocardium. This condition has been linked to severe complications. The aim of this study was to evaluate the incidence of MB in Taiwanese subjects examined with electrocardiogram-gated, 16-slice, multidetector computed tomography (MDCT) coronary angiography, as well as to determine the location, depth, and length of the bridged segments and the concomitant atherosclerosis of MB. METHODS From August 2004 to May 2005, 276 consecutive subjects referred to our department for MDCT coronary angiography were enrolled in the study after written informed consent was obtained from each participant. RESULTS Twenty-four subjects (8.7%) had at least one coronary segment that was completely surrounded by myocardium. Patients ranged in age from 27 to 76 years, with an average of 54 +/- 12 years. Thirty coronary segments were found to have MB. The most common location of MB was in segment 7, which accounted for 14 coronary segments (46.7%) of the total number of bridged segments; left anterior descending artery (LAD) segments accounted for 23 (76.7%); and right coronary artery and left circumflex artery segments accounted for three (10%) and two (6.7%), respectively. The length of bridged segments ranged from 5.2 to 50.6 mm, with an average length of 24.6 +/- 11.8 mm, and the depth of the bridged segments ranged from 0.5 to 9.1 mm, with an average depth of 3.65 +/- 1.89 mm. Two bridged segments (6.7%) had concomitant atherosclerosis; these were located in segment 7 (24.0 mm long and 6.10 mm deep) and segment 8 (27.1 mm long and 7.0 mm deep). Bridged segments with concomitant atherosclerosis were deeper, but not longer, compared with bridged segments without concomitant atherosclerosis (p < 0.05). CONCLUSION Electrocardiogram-gated MDCT is an effective noninvasive tool for evaluating MB in a clinical setting. The most common location of MB was in the LAD, especially in segment 7. Bridged segments with concomitant atherosclerosis were deeper, but not longer, compared with bridged segments without concomitant atherosclerosis.

Percutaneous cryoablation for inoperable malignant lung tumors: midterm results.

OBJECTIVE To retrospectively analyze the efficacy and short- to mid-term survival rate of cryoablation for malignant lung tumors. METHODS Percutaneous CT-guided cryoablation for 45 malignant lung tumors in 26 patients during 41 sessions from 2009 to 2013 were performed. Follow up CT-scan were used to determine local tumor progression. Survival rate, local tumor control rate and associated risk factors were analyzed. RESULTS The immediate during and short-term complications with CTCAE grade 2 or upper include pneumothorax (15%), pleural effusion (20%), pulmonary hemorrhage (24%), pneumonitis (15%), hemothorax (15%), hemoptysis (10%), pain (20%), bronchopleural fistula (n=1), and empyema (n=2). Life-threatening bleeding or hemodynamic instability was not observed. There was no procedural-related mortality. Overall survival rate of 1, 2, 3 years are 96%, 88%, 88%. For curative intent, local tumor control (LTC) rate of 1, 2, 3 years are 75%, 72%, 72%. CONCLUSION Cryoablation for malignant lung tumors is effective and feasible in local control of tumor growth, with good short- to mid-term survival rate, as an alternative option for inoperable patients.

Frequency and risk factors associated with atherosclerotic plaques in patients with a zero coronary artery calcium score.

Background: Analysis of the coronary artery calcium levels usually provides important information that can be used in patient prognosis and stratification of treatment when coronary artery disease is suspected. However, plaques, with or without significant stenosis, have been reported in patients without coronary artery calcium. The aim of this study was to determine the frequency and risk factors of the development of coronary artery plaques in individuals with a zero calcium score. Methods: Analysis of coronary artery calcium levels and coronary computed tomography angiography (CTA) were performed using 64‐slice computed tomography (CT). The demographic data, clinical risk factors, and imaging features of 519 consecutive patients (54 ± 10 years, male:female ratio of 56:44) were retrospectively analyzed. The presence of plaques and the degree of the resulting stenosis were recorded. Descriptive, univariate, and multivariate analyses were carried out to identify the frequency and risk factors associated with the presence of coronary artery plaques. Results: Among 66 patients, 82 coronary arteries were found to have plaques, and six coronary arteries showed significant stenosis. Univariate analysis showed that an age greater than 55 years, male gender, a body mass index (BMI) of more than 27, hypertension, and diabetes mellitus are significant factors associated with the development of coronary artery plaques. Multivariate logistic regression analysis showed that an age over 55 years (p = 0.012, OR = 2.13, 95% C.I. = 1.18–3.84) and BMI greater than 27 (p = 0.026, OR = 2.01, 95% C.I. = 1.09–3.72) are independent factors associated with the presence of plaques in patients with a zero calcium score. Conclusion: The results of this study show that plaques are present in a significant proportion of individuals with a zero coronary artery calcium score. In addition, advanced age and obesity are risk factors associated with the development of plaques.

Outcome comparison between thoracic endovascular and open repair for type B aortic dissection: A population-based longitudinal study

Background Management of diseases of the descending thoracic aorta is trending from open surgery toward thoracic endovascular aortic repair (TEVAR), because TEVAR is reportedly associated with less perioperative mortality. However, comparisons between TEVAR and open surgery, adjusting for patient comorbidities, have not been well studied. In this nationwide population‐based study, we compared the outcomes between TEVAR and open surgery in type B aortic dissection. Methods From 2003 to 2009, data on patients with type B aortic dissection who underwent either open surgery or TEVAR were obtained from the National Health Insurance Research Database. Survival, length of stay, and complications were compared between TEVAR and open repair. To minimize possible bias, we performed an additional analysis after matching patients by age, sex, and propensity score. Results A total of 1661 patients were identified, of whom 1542 underwent open repair and 119 TEVAR. Patients in the TEVAR group were older (63.0 ± 15.4 years vs. 58.1 ± 13.1 years; p = 0.001), included more males, and had more preoperative comorbidities. Thirty‐day mortality in the TEVAR group was significantly lower than that in the open repair group (4.2% vs. 17.8%; p < 0.001). The midterm survival rates in the unmatched cohort between the open surgery and TEVAR groups at 1 year, 2 years, 3 years, and 4 years were 76%, 73%, 71%, and 68% vs. 92%, 86%, 82%, and 79%, respectively. The length of stay in the TEVAR group was shorter than that in the open repair group (p = 0.001). The TEVAR group had less respiratory failure (p = 0.022) and fewer wound complications than the open repair group (p = 0.008). The matched cohort showed similar results. Conclusion TEVAR for type B aortic dissection repair has less perioperative mortality, a shorter length of hospitalization, a higher midterm survival rate, less postoperative respiratory failure, and fewer wound complications than open surgery.

Radiation recall pneumonitis induced by epidermal growth factor receptor-tyrosine kinase inhibitor in patients with advanced nonsmall-cell lung cancer.

Background Radiation recall pneumonitis (RRP) is a special form of radiation pneumonitis precipitated by certain pharmacological agents. Epidermal growth factor receptor‐tyrosine kinase inhibitor (EGFR‐TKI) is an effective treatment for advanced nonsmall‐cell lung cancer (NSCLC) and has been reported as a potent radiation sensitizer. The incidence and general characteristics of EGFR‐TKI‐related RRP in patients with NSCLC remain unclear. Methods Clinical records and serial chest images of consecutive patients with advanced NSCLC who had received thoracic radiotherapy (TRT) and EGFR‐TKI treatment were retrospectively reviewed. EGFR‐TKI‐related RRP was diagnosed according to history, clinical manifestations, and radiographic characteristics. Potential risk factors were analyzed. Results In total, 160 patients with NSCLC who received EGFR‐TKI after TRT were identified. Of these patients, seven (4.4%) developed EGFR‐TKI‐related RRP. The median time interval between the end of radiotherapy and RRP was 124 days (range, 80–635 days) and that between the initiation of EGFR‐TKI and RRP was 43 days (range, 18–65 days). No risk factor for the development of RRP was identified except that patients in whom EGFR‐TKI was initiated within 90 days after the completion of radiotherapy had significantly higher rates of RRP than those of patients who began receiving EGFR‐TKI treatment after 90 days (21% vs. 2.1%, p = 0.005). Conclusion In patients with NSCLC who have a history of TRT, treatment with EGFR‐TKI may induce not only interstitial lung disease but also RRP. Physicians should be aware of both unexpected adverse events when using EGFR‐TKI.

Myocardial bridging in Taiwanese: Noninvasive assessment by 64-detector row coronary computed tomographic angiography

Background: Myocardial bridging (MB) is a congenital structural variant in which a segment of the epicardial coronary artery tunnels into and is surrounded by the myocardium. MB has been correlated to some clinical complications of cardiovascular disease (CVD). The depiction rate of MB varies significantly between catheter coronary angiography and autopsy studies. This study aimed to assess the depiction rate of MB among Taiwanese by coronary computed tomographyic angiography (CCTA), to determine the anatomical features of the tunneling vessels, and to evaluate the outcome of patients having MB. Methods: Between September 2006 and December 2007, 425 subjects (264 men and 161 women; mean age 59.6 ± 11.7 years) underwent ECG‐gated CCTA by a 64‐dectector row scanner in our institution. The presence and the location of MB in CCTA images and the presence of atherosclerosis in the tunneling vessels were evaluated and recorded. Major CVD events in the cohort were tracked from the day of CCTA examination until on March 2009 termination of follow‐up. Results: The depiction rate of MB was 20.9% (89/425). A total of 122 MB were depicted by CCTA. Thirty‐six tunneling segments (29.5%) were situated in the distal portion of the left anterior descending coronary artery (LAD), 23 segments (18.8%) were in the middle portion of the LAD, 19 (15.5%) were in the first obtuse marginal branch of the left circumflex artery, 18 (14.7%) in the first diagonal branch of the LAD, and 10 (8.1%) were in the ramus medianus. Nine tunneling segments (7.3%) had concomitant atherosclerotic plaques at the time of CCTA. One hundred and nine tunneled segments (89.3%) were superficially located in the myocardium, with a mean depth of 1.9 ± 0.81 mm (range, 0.9–4 mm). Twelve patients with CVD events were recorded during the mean follow‐up interval of 21.91 ± 4.03 months (range, 3.08–28.82 months). All 12 patients with CVD events had no MB on CCTA. Conclusion: The depiction rate of MB by CCTA was 20.9% in this study. The most common location of MB was in the LAD. Concomitant atherosclerotic plaques were found in 7.3% of MB cases. Eighty‐nine percent of tunneling vessels were superficially situated. None of the enrolled subjects with MB developed CVD event during the follow‐up period. No statistical correlation was found between the presence of MB and CVD event (p = 0.057).

Giant branching aneurysmal aberrant systemic artery for intralobar pulmonary sequestration: Computed tomographic depiction of arterial and bronchial anomaly

Aberrant systemic arteries supplying the intralobar pulmonary sequestration can become dilated and have atherosclerotic change. Computed tomography is very useful in demonstrating the aberrant artery. We report a case of intralobar pulmonary sequestration with giant branching aneurysmal aberrant artery, and demonstrated the discontinuity of the bronchus by 64-slice computed tomography, which has not previously been described.