Wei-Chun Huang

Identification and viability assessment of infarcted myocardium with late enhancement multidetector computed tomography: Comparison with thallium single photon emission computed tomography and echocardiography

BACKGROUND Recent studies revealed that multidetector computed tomography late enhancement (MDCT-LE) is a reliable technique for detecting necrotic and scarred myocardial tissue. The aims of the study were to identify infarcted myocardium using MDCT-LE protocol in patients after myocardial infarction (MI) and assess viability in resting wall motion abnormalities. METHODS One hundred one patients with previous MI (62 +/- 13 years, 1-6 months after MI) underwent MDCT-LE (15 minutes after contrast medium administration), rest-redistribution thallium single photon emission computed tomography (Tl-SPECT), and dobutamine echocardiography (DbE). In a 17-segment model, infarcted myocardium detected by MDCT-LE was categorized as none, 1%-25%, 26%-50%, 51%-75%, or >75% segmental extent and was compared with decreased uptake of Tl-SPECT and contractile function by DbE on per patient and segmental basis in a blinded fashion. RESULTS By per patient analysis, MDCT-LE identified the presence of infarcted myocardium in 97 patients (96%), and Tl-SPECT decreased uptake in 88 patients (87%), (P = .02). By per segment analysis, the concordance for detecting infarcted myocardium was good (kappa value = 0.792). In segments with resting wall motion abnormalities (N = 486), there was moderate concordance in assessing viability (kappa value between MDCT and Tl-SPECT = 0.555, MDCT and DbE = 0.498, Tl-SPECT and DbE = 0.478) with predefined MDCT-LE threshold of 50% segmental extent. Among segments with MDCT-LE >75% segmental extent, the proportion designated nonviable by Tl-SPECT and DbE reached 87.8% and 92.2%, respectively. CONCLUSIONS Multidetector computed tomography late enhancement is accurate in identifying the presence and extent of infarcted myocardium. Its segmental extent has good correlation with the magnitude of thallium decreased uptake and can predict contractile reserve. Multidetector computed tomography late enhancement can be an alternative to assess viability.

Detection of coronary artery disease using real-time myocardial contrast echocardiography: a comparison with dual-isotope resting thallium-201/stress technectium-99m sestamibi single-photon emission computed tomography.

Real-time myocardial contrast echocardiography (MCE) has the potential to evaluate myocardial perfusion and wall motion (WM) simultaneously. The purposes of this study were to correlate the diagnostic value of MCE with radionuclide single-photon emission computed tomography (SPECT), and to assess the sensitivity and specificity of real-time MCE in detecting coronary artery disease (CAD). Seventy patients with clinically suspected CAD underwent MCE and SPECT at baseline and after dipyridamole infusion. Segmental perfusion with MCE using low mechanical index after 0.3–0.4-ml bolus injections of perfluorocarbon exposed sonicated dextrose albumin solution was performed. All patients had a dual-isotope (rest thallium-201, stress sestamibi) study performed both at baseline and after dipyridamole infusion, and 40 patients had subsequent quantitative coronary angiography. Abnormalities were noted in 27 patients (38.6%) by MCE, in 29 patients (41.4%) by WM analysis, and in 30 patients (42.9%) by SPECT imaging. When MCE and WM analysis were combined, the agreement with SPECT imaging improved from 75.7% (Kappa = 0.50) to 82.0% (Kappa = 0.62). In 40 patients (120 territories) who underwent coronary angiography, good perfusion concordance was achieved for the left anterior descending and left circumflex arteries, and was fair for the right coronary arteries. Compared with quantitative angiography, there was no difference in sensitivity, specificity, and accuracy in detecting significant CAD among the three modalities. The combination of MCE and WM had a better sensitivity (84%), specificity (93.3%), and accuracy (87.5%) than the MCE and WM analysis alone. However, the difference did not reach statistical significance. Real-time MCE has a good agreement with SPECT imaging for detecting CAD. The combination of MCE and WM appears to have higher sensitivity, specificity, and accuracy in detecting CAD than either technique alone.

Comparing culprit lesions in ST-segment elevation and non-ST-segment elevation acute coronary syndrome with 64-slice multidetector computed tomography

BACKGROUND Classifying acute coronary syndrome (ACS) as ST elevation ACS (STE-ACS) or non-ST elevation ACS (NSTE-ACS) is critical for clinical prognosis and therapeutic decision-making. Assessing the differences in composition and configuration of culprit lesions between STE-ACS and NSTE-ACS can clarify their pathophysiologic differences. OBJECTIVE This study focused on evaluating the ability of 64-slice multidetector computed tomography (MDCT) to investigate these differences in culprit lesions in patients with STE-ACS and NSTE-ACS. METHODS Of 161 ACS cases admitted, 120 who fit study criteria underwent MDCT and conventional coronary angiography. The following MDCT data were analyzed: calcium volume, Agatston calcium scores, plaque area, plaque burden, remodeling index, and plaque density. RESULTS The MDCT angiography had a good correlation with conventional coronary angiography regarding the stenotic severity of culprit lesions (r=0.86, p<0.001). The STE-ACS culprit lesions (n=54) had significantly higher luminal area stenosis (78.6+/-21.2% vs. 66.7+/-23.9%, p=0.006), larger plaque burden (0.91+/-0.10 vs. 0.84+/-0.12, p=0.007) and remodeling index (1.28+/-0.34 vs. 1.16+/-0.22, p=0.021) than those with NSTE-ACS (n=66). The percentage of expanding remodeling index (remodeling index >1.05) was significantly higher in the STE-ACS group (81.5% vs. 63.6%, p=0.031). The patients with STE-ACS had significantly lower MDCT density of culprit lesions than patients with NSTE-ACS (25.8+/-13.9HU vs. 43.5+/-19.1HU, p<0.001). CONCLUSIONS Sixty-four-slice MDCT can accurately evaluate the stenotic severity and composition of culprit lesions in selected patients with either STE-ACS or NSTE-ACS. Culprit lesions in NSTE-ACS patients had significantly lower luminal area stenosis, plaque burden, remodeling index and higher MDCT density, which possibly reflect differences in the composition of vulnerable culprit plaques and thrombi.

Therapeutic Benefits of Induced Pluripotent Stem Cells in Monocrotaline-Induced Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is characterized by progressive increases in vascular resistance and the remodeling of pulmonary arteries. The accumulation of inflammatory cells in the lung and elevated levels of inflammatory cytokines in the bloodstream suggest that inflammation may play a role in PAH. In this study, the benefits of induced pluripotent stem cells (iPSCs) and iPSC-conditioned medium (iPSC CM) were explored in monocrotaline (MCT)-induced PAH rats. We demonstrated that both iPSCs and iPSC CM significantly reduced the right ventricular systolic pressure and ameliorated the hypertrophy of the right ventricle in MCT-induced PAH rats in models of both disease prevention and disease reversal. In the prevention of MCT-induced PAH, iPSC-based therapy led to the decreased accumulation of inflammatory cells and down-regulated the expression of the IL-1β, IL-6, IL-12α, IL-12β, IL-23 and IFNγ genes in lung specimens, which implied that iPSC-based therapy may be involved in the regulation of inflammation. NF-κB signaling is essential to the inflammatory cascade, which is activated via the phosphorylation of the NF-κB molecule. Using the chemical inhibitor specifically blocked the phosphorylation of NF-κB, and in vitro assays of cultured human M1 macrophages implied that the anti-inflammation effect of iPSC-based therapy may contribute to the disturbance of NF-κB activation. Here, we showed that iPSC-based therapy could restore the hemodynamic function of right ventricle with benefits for preventing the ongoing inflammation in the lungs of MCT-induced PAH rats by regulating NF-κB phosphorylation.

Dual-phase multi-detector computed tomography assesses jeopardised and infarcted myocardium subtending infarct-related artery early after acute myocardial infarction

Objectives: To investigate dual-phase multi-detector computed tomography (MDCT) for assessing extent and severity of jeopardised and infarcted myocardium subtended by infarct-related artery (IRA), and its indication for revascularisation after acute myocardial infarction (AMI). Designs, setting and patients: Prospective, single-centre study included 107 patients with uncomplicated post-AMI 3–7 days, who met criteria and underwent dual-phase 64-slice MDCT. IRA, culprit lesion and extent of jeopardised/infarcted myocardium were assessed by three-dimensional (3D) volume-rendered images with myocardium maps and computed tomography angiography (CTA), compared with stress-redistribution thallium-201 single-photon emission computed tomography (SPECT) plus conventional coronary angiography (CCA). MDCT-jeopardised score (severity of jeopardised myocardium) was defined as extent of jeopardised myocardium multiplied by the weighted factor dependent on culprit lesion severity compared with SPECT-SRS (summation of segmental reversible score). The IRA indication for revascularisation was evaluated by MDCT-jeopardised score plus CTA. SPECT-SRS ⩾2 plus CCA-culprit lesion ⩾50% was the standard reference. Results: The presence of MDCT-delayed enhancement was found in 101 (94.4%) patients. The IRA and culprit lesion were identified in 99 (92.5%) patients by MDCT-myocardium maps plus CTA. The concordance between MDCT and SPECT for detecting infarcted myocardium was good (kappa = 0.702). The correlation between MDCT-jeopardised score and SPECT-SRS was 0.741. The correlation between CTA and CCA for culprit lesion severity was 0.85. The sensitivity, specificity, negative and positive predictive values of MDCT-jeopardised score ⩾2.5 plus CTA for indicating revascularisation were 90.2%, 80.4%, 86.0% and 85.9%, respectively. Conclusions: Dual-phase MDCT has good accuracy for identifying IRA, and assessing infarcted and jeopardised myocardium for clinical relevance. It provides an alternative for triage and therapeutic planning in post-AMI.

Major Events in Uremic Patients: Insight from Parameters Derived by Flow Propagation Velocity

BACKGROUND The parameters derived by flow propagation velocity (FPV) of early-diastolic mitral inflow have been proved to be associated with cardiovascular risk. This study was undertaken to analyze the prognosis of uremic patients by FPV. METHODS A total of 100 uremic patients were enrolled. All patients underwent conventional echocardiographic examination and FPV measurement. Those examinations were performed before and after hemodialysis (within 30 minutes). Patients were followed for 4 years. Major events were recorded and defined as any-cause mortality and nonfatal cardiovascular events with hospitalization. Patients were separated into two groups according to a post-dialytic E/FPV of <1.5 or > or =1.5 (early-diastolic velocity of mitral inflow divided by FPV). RESULTS Twenty-six major events were recorded, including 13 cases with mortality and 13 cases with nonfatal cardiovascular events. The patients with a post-dialytic E/FPV of > or =1.5 had a higher prevalence of underlying coronary arterial disease (30% vs. 17%), left ventricular systolic dysfunction (left ventricular ejection fraction: 46% +/- 10% vs. 52% +/- 8%), and a major event. By Cox regression analysis, a post-dialytic E/FPV of > or =1.5 (hazard ratio 2.358, 95% confidence interval 1.118-4.62, P = .008) was the strongest independent factor to predict the major events, after adjustment of other covariates. CONCLUSION A post-dialytic E/FPV of > or =1.5 predicts higher adverse events in uremic patients.

Role of Shortened QTc Dispersion in In-hospital Cardiac Events in Patients Undergoing Percutaneous Coronary Intervention for Acute Coronary Syndrome

Background: QT dispersion (QTD) refers to the difference between maximal and minimal QT values on the electrocardiogram (ECG). QTD values are calculated and corrected with Bazetts formula (corrected QTD = QTcD = QTD/vRR). QTcD increases in patients with acute coronary syndrome (ACS). Recovery of increased QTcD (shortened QTcD) develops after successful revascularization, but prolonged QTcD occurs in certain patients. The aim of this study is to ascertain the clinical significance between shortened and prolonged QTcD groups after percutaneous coronary intervention (PCI). Methods: We retrospectively enrolled 128 patients with ACS who had received PCI. The values of QTcD were measured manually on 12‐lead standard ECGs obtained within 3 days before and after PCI (pre‐PCI QTcD and post‐PCI QTcD). All the patients were divided into 2 groups. The shortened QTcD group was defined as those patients with a decrease in QTcD after PCI and the prolonged QTcD group as those with an increase in QTcD after PCI. The underlying diseases, various clinical classifications and some prognostic factors were taken into comparison and statistical analysis between these 2 groups. Results: The shortened QTcD group showed a significantly higher rate of in‐hospital cardiac death (13% vs. 0%, p = 0.006) and a greater pre‐PCI QTcD (100.8 ± 39.5 vs. 61.3 ± 24.1 ms, p < 0.001) than the prolonged QTcD group. There was a significantly greater pre‐PCI QTcD in patients with cardiac death than those without cardiac death (111.6 ± 38.3 vs. 83.3 ± 38.3 ms, p = 0.027). Furthermore, the patients with in‐hospital cardiac death presented with a significantly more frequent occurrence of in‐hospital ventricular arrhythmia, compared with those without cardiac death (30.0% vs. 4.0%, p = 0.014). Conclusion: Among the patients with ACS undergoing PCI, directly divided into shortened and prolonged QTcD groups regardless of initial pre‐PCI QTcD, the shortened QTcD group showed a higher occurrence of in‐hospital cardiac death and a greater pre‐PCI QTcD. Shortened QTcD might be 1 risk factor for in‐hospital cardiac death.

Increased Risk of Intracranial Hemorrhage in Patients With Pregnancy-Induced Hypertension: A Nationwide Population-Based Retrospective Cohort Study.

Abstract Pregnancy-induced hypertension (PIH) may be a major predictor of pregnancy-associated intracranial hemorrhage (ICH). However, the relationship between PIH and long-term ICH risk is unknown. The objective of the study was to determine the association between PIH and ICH and to identify the predictive risk factors. Patients with newly diagnosed PIH were recruited from the Taiwan National Health Insurance Research Database. PIH patients were divided into gestational hypertension (GH) and preeclampsia groups. The 2 groups were separately compared with matched cohorts of patients without PIH based on age and date of delivery. The occurrence of ICH was evaluated in both cohorts. The overall observational period was from January 1, 2000 to December 31, 2013. Among the 23.3 million individuals registered in the National Health Insurance Research Database, 28,346 PIH patients, including 7390 with GH and 20,956 with preeclampsia, were identified. The incidences of ICH were increased in both groups (incidence rate ratio [IRR] = 3.72 in the GH group, 95% confidence interval [CI] 3.63–3.81, P < 0.0001 and IRR = 8.21 in the preeclampsia group, 95% CI 8.12–8.31, P < 0.0001, respectively). In addition, according to the results of stratification of follow-up years, both groups were associated with a highest risk of ICH at 1 to 5 years of follow-up (IRR = 11.99, 95% CI 11.16–12.88, P < 0.0001 and IRR = 21.83, 95% CI 21.24–22.44, P < 0.0001, respectively). After adjusting for age, parity, severity of PIH, number of PIH occurrences, gestational age, and comorbidities in the multivariate survival analysis using Cox regression model, age ≥30 years (hazard ratio [HR] 1.99, 95% CI 1.27–3.10, P = 0.0026), patients with preeclampsia (HR 2.18, 95% CI 1.22–3.90, P = 0.0089), multiple PIH occurrences (HR 4.08, 95% CI 1.85–9.01, P = 0.0005), hypertension (HR 4.51, 95% CI 1.89–10.74, P = 0.0007), and obesity (HR 7.21, 95% CI 1.58–32.84, P = 0.0107) were independent risk factors for the development of ICH among patients with PIH. Patients with PIH, especially those with older age, preeclampsia, and multiple PIH occurrences, may have an increased risk of developing ICH later in life.

The effect of failure mode and effect analysis on reducing percutaneous coronary intervention hospital door-to-balloon time and mortality in ST segment elevation myocardial infarction

Background Door-to-balloon (D2B) time is an important factor in the outcome of ST segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention. We aimed to use failure mode and effect analysis to reduce the D2B time for patients with STEMI and to improve clinical outcomes. Methods There were three stages in this study. In Stage 0, data collected from 2005–2006 was used to identify failures in the process, and during Stage 2 (2007) and Stage 3 (2008) the efficacy of intrahospital and interhospital strategies to reduce the D2B time were evaluated. This study enrolled 385 patients; 86 from 2005–2006; 80 in 2007; and 219 in 2008. Results By making improvements in these steps, the median D2B time was reduced from 146 min to 32 min for all patients. The proportion of patients with a D2B time of <90 min significantly increased from Stage 0 to Stage 1 and from Stage 1 to Stage 2, for all patients as well as for the non-transferred and transferred subgroups of patients (all p values <0.0001). For non-transferred patients, only reinfarction-free survival showed significant difference among the three stages (p=0.0225), and for transferred patients, only overall survival showed significant difference among the three stages (p=0.0322). Coxs proportional hazards regression analysis showed Stage 2 was associated with a lower risk of reinfarction and mortality compared with Stage 0. Conclusions This study found that failure mode and effect analysis is a powerful method for identifying weaknesses in D2B processes and evaluating strategies to reduce the D2B time.

Tricuspid flow propagation velocity predicts exercise tolerance and readmission in patients with systemic lupus erythematosus.

BACKGROUND Evaluating right ventricular dysfunction, pulmonary artery systolic pressure (PASP), and exercise tolerance is critical in patients with systemic lupus erythematosus (SLE) because of the high mortality rate in such patients with pulmonary arterial hypertension (PAH). The aim of this study was to use the flow propagation velocity (FPV) of early diastolic tricuspid inflow to evaluate exercise tolerance and PAH severity and to predict readmission in patients with SLE. METHODS A total of 66 patients with SLE with or without PAH and 30 healthy control subjects were enrolled. Controls were age-matched to patients with SLE and without PAH. All patients completed the 6-minute walking distance (6MWD) test and underwent standard echocardiography. Tricuspid FPV was measured in the modified parasternal short-axis view using the color M-mode technique. PAH was defined as PASP > 35 mm Hg using the tricuspid regurgitant method. RESULTS Patients with SLE and PAH had significantly lower tricuspid FPVs and 6MWDs than patients in the other 2 groups (both P values < .001). Tricuspid FPV was well correlated with 6MWD (r = 0.748, P < .001). In multivariate analysis, right atrial pressure was the only independent factor affecting tricuspid FPV (R(2) = 0.394, P < .001), and 6MWD was affected only by tricuspid FPV and PASP (R(2) = 0.629, P < .001). Patients with SLE who had been readmitted had lower tricuspid FPVs than those who had not (P = .035). Furthermore, FPV > or = 35.4 cm/s predicted 6MWD > or = 350 m and a lower 1-year readmission rate with good sensitivity and specificity. CONCLUSION The tricuspid FPV technique provides a simple method for predicting exercise tolerance, the severity of PAH, and readmission among patients with SLE.