Yalcin Hacioglu

Comparison of Transesophageal Echocardiography Versus Computed Tomography for Detection of Left Atrial Appendage Filling Defect (Thrombus)

Patients with atrial fibrillation, who are referred for radiofrequency pulmonary vein antral isolation, frequently undergo transesophageal echocardiography (TEE) to detect and/or exclude left atrial or left atrial appendage (LAA) thrombus and cardiac computed tomographic angiography (CCTA) to define and/or evaluate left atrial and pulmonary venous anatomy. Previous studies have reported CCTA to have high sensitivity and negative predictive value (NPV) for detecting thrombus in the LAA. Previous studies determining an optimal LAA/ascending aorta (AA) Hounsfield unit (HU) density ratio for detection of LAA thrombus have been small, with limited numbers of thrombi. We thus sought to determine both the optimal cutoff for LAA HU density and LAA/AA HU density ratio in detecting LAA thrombus compared with TEE in a multicenter population. We included 84 patients who had undergone CCTA and TEE. LAA was evaluated by 64-row CCTA qualitatively (visual filling defect) and quantitatively (measurement of LAA HU density and LAA/AA HU density ratio), using a 1-cm area of interest in the same axial plane. Results were compared with TEE visualization of thrombus or spontaneous echo contrast. Qualitative identification of thrombus in LAA by CCTA compared with TEE detection of thrombus had a sensitivity of 100%, a specificity of 77.9%, a positive predictive value (PPV) of 51.6%, an NPV of 100%, and a total accuracy of 82.1%. The optimal LAA HU density cutoff for thrombus detection was 119 with a sensitivity of 88%, a specificity of 86%, PPV 56%, and an area under the curve of 0.923 (p = 0.0004). The optimal LAA/aorta HU ratio was 0.242 with a sensitivity of 87%, a specificity of 88%, a PPV of 64%, and an area under the curve of 0.921 (p = 0.0011). There is no significant difference (p = 0.72) between both areas under the curve, and both measurements improved the specificity and PPV compared with qualitative measures. Multidetector computed tomography is an imaging technique that can exclude LAA thrombus with very high NPV. Quantitative measurement of LAA HU density (cutoff 119) or LAA/aorta HU density ratio (cutoff 0.242) improves accuracy of positively detecting LAA thrombus. This technique is especially useful when delayed scanning is not performed and LAA is found incidentally after the patient scanning is complete.

Noninvasive Anatomical Coronary Artery Imaging Versus Myocardial Perfusion Imaging: Which Confers Superior Diagnostic and Prognostic Information?

Myocardial perfusion imaging (MPI) has been a valuable diagnostic and prognosticating tool for decades, but recently it has been challenged by the growing evidence about either comparable or superior diagnostic and prognostic value of computed tomography (CT)-based anatomical imaging modalities. Although there are some studies suggesting synergy and potential for combined use of these modalities to better diagnose coronary artery disease (CAD), it is important to evaluate these approaches separately, given cost and other restraints. This review compares the noninvasive anatomical imaging modalities of coronary artery calcium scoring and coronary CT angiography to the functional assessment modality of MPI in the diagnosis and prognostication of significant CAD in symptomatic patients. A large number of studies investigating this subject are analyzed with a critical look on the evidence, underlying the strengths and limitations. Although the overall findings of the presented studies are favoring the use of CT-based anatomical imaging modalities over MPI in the diagnosis and prognosticating of CAD, the lack of a high number of large- scale, multicenter randomized controlled studies limits the generalizability of this early evidence. Further studies comparing the short- and long-term clinical outcomes and cost-effectiveness of these tests are required to determine their optimal role in the management of symptomatic patients with suspected CAD.

Differences in Coronary Atherosclerotic Plaque Burden and Composition According to Increasing Age on Computed Tomography Angiography

RATIONALE AND OBJECTIVES Few data were available regarding the underlying burden of specific plaque types with increasing ages. The aim of this study was to assess the relationship of coronary artery calcium (CAC) score with total coronary plaque burden and the difference of underlying coronary plaque composition across differing aging groups using 64-slice multidetector computed tomography. MATERIALS AND METHODS Multidetector computed tomographic images of 781 consecutive patients were evaluated using a 15-coronary segment model. Segment involvement score (the total number of segments with any plaque), segment stenosis score (the sum of maximal stenosis score per segment), total plaque score (the sum of the plaque amount per segment), and plaque composition were measured to compare with total CAC scores stratified by age tertile (lowest [n = 274], <55 years; middle [n = 242], 55-65 years; highest [n = 265], >65 years). RESULTS The mean age of the study population was 59 ± 13 years (481 men [62%]). With increasing age, higher segment involvement scores, segment stenosis scores, and total plaque scores were noted. Plaque burden was correlated significantly with total CAC scores in all tertiles. The percentage of partially calcified (P < .001) and calcified (P < .001) plaque increased with age, and in the highest age tertile, 87% of plaque contained calcium (calcified or mixed), compared to only 63% in the younger patients (P < .001). Those aged >65 years were highly unlikely to have isolated noncalcified plaque (in the setting of a calcium score of 0). Younger patients were 10 times more likely to have isolated noncalcified plaque (P < .001). CONCLUSIONS The absence of CAC strongly excludes obstructive disease, and CAC predicts the presence of coronary atherosclerotic plaque. However, the absence of any CAC does not exclude the presence of coronary atherosclerotic plaque, especially in patients aged <55 years. Plaque composition shifted from noncalcified to calcified plaque with increasing age, which may affect the vulnerability of these lesions over time.

Coronary CT angiography offers further risk stratification in the management of patients with normal SPECT results

Risk stratification strategies used in the diagnosis and management of coronary artery disease (CAD) aim to identify patients with intermediate to high likelihood of significant CAD that might benefit from coronary revascularizations and/or aggressive medical therapy. Myocardial perfusion imaging (MPI) has been an integral part of the traditional risk stratification algorithm for more than two decades. While the presence of significant ischemia on MPI usually necessitates further evaluation with coronary catheterization, patients with normal or low risk scans are mostly managed medically. Even though a normal MPI result generally indicates a benign prognosis, the ‘‘warranty period’’ of such result could be substantially shorter in patients with certain clinical risk factors such as adenosine stress (due to inability to exercise), increasing age, diabetes, female gender in diabetics, and history of known CAD indicating a lower negative predictive value for MPI in this

Relation of subclinical left and right ventricular dysfunctions measured by computed tomography angiography with the severity of coronary artery disease.

ObjectiveVentricular dysfunction in asymptomatic patients is directly linked to the eventual development of symptomatic congestive heart failure. This study investigates whether subclinical left ventricular (LV) and right ventricular (RV) dysfunctions measured by computed tomography angiography is associated with the severity of coronary artery disease (CAD). Methods and resultsWe studied 1608 consecutive patients with suspected CAD (age 62±10 years, 64% male), who underwent coronary artery calcium (CAC) scanning and computed tomography angiography. RV and LV volumes at end systole and end diastole were measured, and stroke volume and ejection fraction were calculated using the Simpson method and piecewise smooth subdivision surface (PSSS) method. Analysis by Simpson was performed on short axis and apical four-chamber views. Axial images were used to measure RV and LV volumes by the PSSS method. CAD was defined as normal, nonobstructive, and obstructive (0% stenosis, luminal stenosis 1–49 and 50%+, respectively). There was a strong agreement between PSSS and Simpson method RV ejection fraction (RVEF) and LV ejection fraction (LVEF) measurement. RVEF and LVEF decreased proportionally from CAC 0 to CAC 100+, also from normal-to-diseased coronaries (P=0.001). After adjustment for cardiovascular risk factors, the mean LVEF and RVEF decreased 2.8 and 2.4%, respectively in CAC 100+ compared with CAC 0. Similarly, LVEF and RVEF decreased significantly in nonobstructive CAD (−3.5 and −3.1%, respectively) and obstructive CAD (−5.9 and −4.5%, respectively) compared with normal coronaries, respectively (P<0.05). The relative risk of each 5% decrease in LVEF and RVEF was 1.33 and 1.29 for nonobstructive CAD and 1.54 and 1.33 for obstructive CAD, respectively. ConclusionThe presence and severity of coronary atherosclerosis is significantly associated with subclinical RV and LV dysfunctions.

Is the left anterior descending artery really absent?--a decisive input from coronary CT angiography.

This case report emphasizes the importance of coronary CT angiography (CTA) as a backup imaging modality in patients with suspected coronary anomalies and difficult canulation, during invasive coronary angiography by catheterization (Cath). In this patient, the numerous canulation attempts during Cath failed to identify a left anterior descending artery (LAD) leading to the diagnosis of absent LAD. CTA was done for further clarification, which easily visualized LAD originating from a separate ostium at the left sinus of Valsalva finalizing the diagnosis as absent left main artery with dual left coronary ostia.

CLINICAL AND PROGNOSTIC VALUE OF POST STENTING FFR FOR ASSESSMENT OF ISCHEMIA REDUCTION IN PATIENTS WITH ACUTE CORONARY SYNDROMES

results: Of 176 patients with ACS (age 63+/-10 years, 47% diabetics), 65 patients had NSTEMI and 111 unstable angina. PCI lead to angiographic lesion reduction from 76+13% to 1.2+6% with significant ischemia reduction from baseline FFR 0.63+-0.15 to PSFFR 0.90+0.6 (p<0.0001). PS-FFR identified 23 patients (13%) who had persistent ischemia (<0.80) despite angiographically optimal results. The low FFR prompted a subsequent intervention including post dilation or placement of another stent improving FFR on repeat measurement (0.73 +0.06 to 0.85+ 0.05; P<0.0001). The clinical utility of PS-FFR was similar for patients with NSTEMI and unstable angina. ROC analysis identified a cutoff of 0.86 for PS-FFR for MACE prediction in ACS population at a mean follow up of 2.7(+ 1.4) years

Determination and distribution of left ventricular size as measured by noncontrast CT in the Multi-Ethnic Study of Atherosclerosis

BACKGROUND Left ventricular (LV) volume and mass have prognostic relevance. Overall size of the left ventricle as it appears in noncontrast CT is a composite of the ventricular volume and myocardial mass. We describe a method to estimate the LV size using a single cross-section in noncontrast CT and determined normal ranges on the basis of a large population cohort. METHODS The Multi-Ethnic Study of Atherosclerosis with 6814 participants from 4 ethnicities who were free of known cardiovascular disease and enrolled between 2000 and 2002 form the basis of our analysis. LV size was calculated from a single cross-sectional slice obtained by either nonenhanced electron beam or multidetector CT. LV size was adjusted to body surface area to obtain the LV size index, which was adjusted for age, sex, race or ethnicity, hypertension, hyperlipidemia, and diabetes. RESULTS There were significant differences in LV size index by race which were further influenced by age and sex. Higher values were noted in men in all ethnic groups across all age groups. Similarly, LV size index uniformly decreased with age across all ethnic and sex categories. Caucasians had the lowest and African Americans had the highest LV size index across all age and sex categories. In multivariate regression analyses adjusted for age, sex, race or ethnicity, hypertension, hyperlipidemia, smoking, and diabetes mellitus, the significant differences were noted between male vs female (median difference, 17.5 cc/m(2); P < .001), ethnic groups (Caucasian, reference group; Asian, 3.7 cc/m(2); African American, 8.3 cc/m(2); and Hispanic, 5.6 cc/m(2); P < .001), and age groups (45-54 years, reference group; 55-64 years, -5.2 cc/m(2); 65-74 years, -11.4 cc/m(2); and 74-84 years, -12.5 cc/m(2)). CONCLUSIONS This study provides normative values for LV size as determined from a single, nonenhanced CT cross-section and indexed to body surface area, and it demonstrates that the LV size index varies by age, sex, and ethnic background.

NORMAL VALUES OF LEFT VENTRICULAR FILLING INDICES BY MULTI-DETECTOR COMPUTED TOMOGRAPHY

Background: In contrast to its well recognized value in the assessment of left ventricular (LV) systolic function, little is known about the role of Multi-detector CT (MDCT) in the evaluation of left ventricular diastolic function. This study aimed to determine the normal reference values for various LV filling indices in patients with normal systolic function and no evidence of significant coronary atherosclerosis, hypertension or diabetes.