Archive for August, 2009

Aug200931

Ronen Rubinshtein

2

Comparison of Dual-Energy Computed Tomography of the Heart with Single Photon Emission Computed Tomography for Assessment of Coronary Artery Stenosis and of the Myocardial Blood Supply

Am J Cardiol. 2009; 104(3):318-326

Ruzsics B, Schwarz F, Schoepf UJ, Lee YS, Bastarrika G, Chiaramida SA, Costello P, Zwerner PL

OBJECTIVES: To evaluate the performance of dual-energy computed tomography (DECT) for integrative imaging of the coronary artery morphology and the myocardial blood supply.

METHODS: 36 patients (15 women, mean age 57 +/- 11 years) with equivocal or incongruous single photon emission CT (SPECT) results were investigated by a single-contrast medium-enhanced, retrospectively electrocardiographic-gated dual-energy CT (DECT) scan with simultaneous acquisition of high and low x-ray spectra. Thirteen patients subsequently underwent invasive coronary angiography (ICA). The DECT data were used to reconstruct anatomic coronary CT angiographic images and to map the myocardial iodine distribution within the left ventricular myocardium. Two independent observers analyzed all DECT studies for stenosis and myocardial iodine defects. A segmental comparison was performed between the stress/rest SPECT perfusion defects and DECT iodine defects and between the ICA and coronary CT angiographic findings for stenosis. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were estimated, along with the kappa statistics.

RESULTS: Overall, DECT had 92% sensitivity and 93% specificity, with 93% accuracy for detecting any type of myocardial perfusion defect seen on SPECT. Contrast defects at DECT correctly identified 85 (96%) of 89 fixed and 60 (88%) of 68 reversible myocardial perfusion defects. The interobserver agreement was very good (weighted kappa = 0.87). Compared with ICA, coronary CT angiography had 90% sensitivity, 94% specificity, and 93% accuracy for the detection of >50% stenosis. In

CONCLUSIONS: Our initial experience suggests that DECT, as a single examination, might be promising for the integrative analysis of the coronary artery morphology and the myocardial blood supply and is in good agreement with ICA and SPECT.

PMID: 19616661

Aug200929

Ronen Rubinshtein

4

Multislice Computed Tomography in the Exclusion of Coronary Artery Disease in Patients with Presurgical Valve Disease

Circ Cardiovasc Imaging. 2009; 2(4):306-313

Nuno Bettencourt MD, João Rocha, Mónica Carvalho, Daniel Leite, Andre Michael Toschke MD, Bruno Melica MD, Lino Santos MD, Alberto Rodrigues MD, Manuel Gonçalves MD, Pedro Braga MD, Madalena Teixeira MD, Lino Simões MD, Sanjay Rajagopalan MD, Vasco Gama MD

jc large iconBACKGROUND: Multislice computed tomography (MSCT) has shown high negative predictive value in ruling out obstructive coronary artery disease. Preliminary studies in patients with valvular heart disease (VHD) have demonstrated the potential of MSCT angiography (CTA) in such patients, precluding need for invasive angiography (XA). However, larger prospectively designed studies, including patients with atrial fibrillation and incorporating dose reduction algorithms, are needed.

METHODS: To evaluate the clinical utility of 64-slice CT in the preoperative assessment in patients with VHD, we prospectively studied 452 consecutive patients undergoing routine cardiac catheterization for eligibility. Two hundred thirty-seven patients underwent both MSCT and XA. Segment-based, vessel-based, and patient-based agreement between CTA and XA was estimated assuming that “nonevaluable” segments were positive for significant coronary stenosis.

RESULTS: In a patient-based analysis, sensitivity, specificity, positive predictive value, and negative predictive values of CTA were 95%, 89%, 66%, and 99%, respectively; in vessel-based analysis, 90%, 92%, 48%, and 99%, respectively; and in segment-based analysis, 89%, 97%, 38%, and 100%, respectively. No significant differences were found between patients with or without atrial fibrillation. A CAC value of 390 was the best cutoff for the identification of patients with positive or inconclusive CTA (which would not be exempted from XA in the clinical setting).

CONCLUSIONS: In the preoperative assessment of patients with predominant VHD, the diagnostic accuracy of 64-slice CTA for ruling out the presence of significant coronary artery disease is very good even when including patients with irregular heart rhythm. Using this approach, CAC quantification before CTA can be successfully used to identify patients who should be referred directly to XA, sparing unnecessary exposure to radiation.

PMID: 19808611

Aug200924

Paul Schoenhagen

1

Geometry and Degree of Apposition of the CoreValve ReValving System With Multislice Computed Tomography After Implantation in Patients with Aortic Stenosis

J Am Coll Cardiol. 2009; 54(10):911-918

Carl J. Schultz, Annick Weustink, Nicolo Piazza, Amber Otten, Nico Mollet, Gabriel Krestin, Robert J. van Geuns, Pim de Feyter, Patrick W.J. Serruys, Peter de Jaegere

OBJECTIVES: Using multislice computed tomography (MSCT), we sought to evaluate the geometry and apposition of the CoreValve ReValving System (CRS, Medtronic, Luxembourgh, Luxembourgh) in patients with aortic stenosis. Background: There are no data on the durability of percutaneous aortic valve replacement. Geometric factors may affect durability.

METHODS: Thirty patients had MSCT at a median 1.5 months (interquartile range [IQR] 0 to 7 months) after percutaneous aortic valve replacement. Axial dimensions and apposition of the CRS were evaluated at 4 levels: 1) the ventricular end; 2) the nadir; 3) central coaptation of the CRS leaflets; and 4) commissures. Orthogonal smallest and largest diameters and cross-sectional surface area were measured at each level.

RESULTS: The CRS (26-mm: n = 14, 29-mm: n = 16) was implanted at 8.5 mm (IQR 5.2 to 11.0 mm) below the noncoronary sinus. None of the CRS frames reached nominal dimensions. The difference between measured and nominal cross-sectional surface area at the ventricular end was 1.6 cm2 (IQR 0.9 to 2.6 cm2) and 0.5 cm2 (IQR 0.2 to 0.7 cm2) at central coaptation. At the level of central coaptation the CRS was undersized relative to the native annulus by 24% (IQR 15% to 29%). The difference between the orthogonal smallest and largest diameters (degree of deformation) at the ventricularend was 4.4 mm (IQR 3.3 to 6.4 mm) and it decreased progressively toward the outflow. Incomplete apposition of the CRS frame was present in 62% of patients at the ventricular end and was ubiquitous at the central coaptation and higher.

CONCLUSIONS: Dual-source MSCT demonstrated incomplete and nonuniform expansion of the CRS frame, but the functionally important mid-segment was well expanded and almost symmetrical. Undersizing and incomplete apposition were seen in the majority of patients.

PMID: 19712801

Aug200916

Eric Williamson

1

Prognostic Value of a Comprehensive Cardiac Magnetic Resonance Assessment Soon After a First ST-Segment Elevation Myocardial Infarction

JACC Cardiovasc Imaging. 2009; 2(7):835-842

Bodi V, Sanchis J, Nunez J, Mainar L, Lopez-Lereu MP, Monmeneu JV, Rumiz E, Chaustre F, Trapero I, Husser O, Forteza MJ, Chorro FJ, Llacer A

OBJECTIVES: To evaluate the prognostic value of a comprehensive cardiac magnetic resonance (CMR) assessment soon after a first ST-segment elevation myocardial infarction (STEMI). Background: CMR allows for a simultaneous assessment of wall motion abnormalities (WMA), WMA with low-dose dobutamine (WMA-dobutamine), microvascular obstruction, and transmural necrosis. This approach has been proven to be useful to predict late systolic recovery soon after STEMI. Its prognostic value and the relative prognostic weight of these indexes are not well-defined.

METHODS: We studied 214 consecutive patients with a first STEMI treated with thrombolytic therapy or primary angioplasty discharged from hospital. In the first week (7 +/- 1 day after infarction), with CMR we determined the extent (number of segments) of WMA, WMA-dobutamine, microvascular obstruction, and transmural necrosis.

RESULTS: During a median follow-up of 553 days, 21 major adverse cardiac events (MACE) including 4 cardiac deaths, 6 nonfatal myocardial infarctions, and 11 readmissions for heart failure were documented. The MACE was associated with a larger extent of WMA (8 +/- 4 segments vs. 5 +/- 3 segments, p < 0.001), WMA-dobutamine (6 +/- 4 segments vs. 4 +/- 3 segments, p = 0.004), microvascular obstruction (3 +/- 3 segments vs. 1 +/- 2 segments p <0.001), and transmural necrosis (7 +/- 3 segments vs. 3 +/- 3 segments, p < 0.001). In a complete multivariate analysis that included baseline characteristics, electrocardiogram, biomarkers, angiography, ejection fraction, left ventricular volumes, and all CMR indexes, WMA/segment (hazard ratio: 1.29 [95% confidence interval: 1.11 to 1.49], p = 0.001) and the extent of transmural necrosis/segment (hazard ratio: 1.30 [95% confidence interval: 1.12 to 1.51], p < 0.001) were the only independent prognostic variables.

CONCLUSIONS: A comprehensive CMR assessment is useful for stratifying risk soon after STEMI, but only the extent of systolic dysfunction and of transmural necrosis provide independent prognostic information.

PMID: 19608133

Aug200915

Paul Schoenhagen

4

Feasibility of Dual-Source Cardiac CT Angiography with High-Pitch Scan Protocols

J Cardiovasc Comput Tomogr. 2009 ; 3(4):236-242

Hausleiter J, Bischoff B, Hein F, Meyer T, Hadamitzky M, Thierfelder C, Allmendinger T, Flohr TG, Schömig A, Martinoff S

OBJECTIVES: Cardiac CT angiography (CCTA) has become a frequently used diagnostic tool in clinical practice, but concern remains about the radiation exposure. Because of the second x-ray acquisition system, dual-source CT systems might allow for high-pitch CT data acquisition and thus for examination of the whole heart during a single heart beat, with the potential for radiation dose reduction. We assessed the feasibility of a high-pitch scan mode with a dual-source CT system.

METHODS: High-pitch modes were used in patients undergoing CCTA with a dual-source CT system. Diagnostic image quality for cardiac structures and coronary arteries was assessed. Radiation dose was estimated from the scanner-generated dose-length product (DLP).

RESULTS: CCTA was performed in 14 patients during a single heart beat applying a pitch value of 3.4. Mean heart rate during examination was 56.4+/-8.1 beats/min. Diagnostic image quality for the assessment of larger cardiac structures was obtained in all patients, whereas diagnostic image quality could be achieved in 82% of all coronary segments. With a mean DLP of 145+/-47 mGy x cm, the resulting estimated radiation dose was 2.0+/-0.7 mSv.

CONCLUSIONS: This proof-of-concept study shows the ability of dual-source CT scanners to scan the whole heart during one single heart beat at low radiation dose.

PMID: 19577211

Aug200915

Paul Schoenhagen

3

Impact of a Reduced Tube Voltage on CT Angiography and Radiation Dose: Results of the PROTECTION I Study

JACC Cardiovasc Imaging. 2009; 2(8):940-946

Bischoff B, Hein F, Meyer T, Hadamitzky M, Martinoff S, Schömig A, Hausleiter J

OBJECTIVES: The aim of this study was to determine the impact of a reduced 100-kV tube voltage on image quality and radiation exposure in a pre-defined subgroup analysis of the international, multicenter radiation dose survey PROTECTION I (Prospective Multicenter Study on RadiaTion Dose Estimates Of Cardiac CT AngIOgraphy I) study. Background: Cardiac computed tomography angiography (CCTA) has become a frequently used diagnostic tool in clinical practice. Despite continually improving CT technology, there remain concerns regarding the associated radiation exposure. A reduced tube voltage of 100 kV has been proposed as an effective means for dose reduction in nonobese patients.

METHODS: The study assessed the relevant radiation dose parameters as well as quantitative and qualitative diagnostic image quality data in a subgroup of 321 patients (100 kV: 82 patients; 120 kV: 239 patients), who were scanned at study sites that applied a 100-kV tube voltage in at least 1 patient. Diagnostic image quality was assessed by an experienced CCTA investigator with a 4-point score (1: nondiagnostic to 4: excellent image quality). Effective radiation dose was estimated from the dose-length-product of each CCTA study.

RESULTS: The use of the 100-kV scan protocol was associated with 53% reduction in CCTA median radiation dose estimates, when compared with the conventional 120-kV scan protocol (p < 0.001). Although image noise significantly increased by 26.3% with 100 kV, signal- as well as contrast-to-noise ratios also increased by 7.9% (p = 0.254) and 10.8% (p = 0.027), respectively. Reduction of tube voltage did not impair diagnostic image quality (median diagnostic score: 3.5 [3.25 to 3.75] vs. 3.5 [3.0 to 3.75] for 100 kV vs. 120 kV; p = 0.22).

CONCLUSIONS: In this nonrandomized PROTECTION I dose survey, reducing the CCTA tube voltage to 100 kV in nonobese patients is associated with a significant reduction in radiation exposure while maintaining diagnostic image quality. Thus, the 100-kV scan technique should be considered for CCTA dose reduction in adequately selected patients.

PMID: 19679281

Aug200911

Paul Schoenhagen

1

Low Dose CT Coronary Angiography for the Prediction of Myocardial Ischaemia

Eur Radiol. 2009; 38(9):79-94

Stolzmann P, Donati OF, Scheffel H, Azemaj N, Baumueller S, Plass A, Kozerke S, Leschka S, Grünenfelder J, Boesiger P, Marincek B, Alkadhi H

OBJECTIVES: The purpose of this study was to prospectively determine the accuracy of low-dose computed tomography coronary angiography (CTCA) for the diagnosis of functionally relevant coronary artery disease (CAD) using cardiac magnetic resonance (CMR) as a standard of reference.

METHODS: Forty-one consecutive patients (age 64 +/- 10 years) underwent k-space and time broad-use linear acquisition speed-up technique accelerated CMR (1.5 T) and dual-source CTCA using prospective electrocardiography gating within 1 day. CTCA lesions were analysed and diameter stenoses of more than 50% and more than 75% were compared with CMR findings taken as the reference standard for assessing the functional relevance of CAD.

RESULTS: CMR revealed perfusion defects in 21/41 patients (51%). A total of 569 coronary segments were analysed with low-dose CTCA. The image quality of low-dose CTCA was diagnostic in 566/569 segments (99.5%) in 39/41 patients (95%). Low-dose CTCA revealed stenoses of more than 50% in 58/123 coronary arteries (47.2%) in 24/41 patients (59%) and more than 75% stenoses in 46/123 coronary arteries (37.4%) in 23/41 patients (56%). Using a greater than 50% diameter stenosis, low-dose CTCA yielded the following per artery sensitivity, specificity, positive and negative predictive values, and accuracy for the detection of perfusion defects: 89%, 79%, 72%, 92% and 83%, respectively.

CONCLUSIONS: Low-dose CTCA is reliable for ruling out functionally relevant CAD, but is a poor predictor of myocardial ischaemia.

PMID: 19657647

Aug200908

Jacobo Kirsch

3

Major Prognostic Impact of Persistent Microvascular Obstruction as Assessed by Contrast-Enhanced Cardiac Magnetic Resonance in Reperfused Acute Myocardial Infarction

Eur Radiol. 2009; 19(9):2117-2126

Cochet AA, Lorgis L, Lalande A, Zeller M, Beer JC, Walker PM, Touzery C, Wolf JE, Brunotte F, Cottin Y

OBJECTIVES: The aim of this study was to compare the prognostic significance of microvascular obstruction (MO) and persistent microvascular obstruction (PMO) as assessed by cardiac magnetic resonance (CMR) in patients with acute myocardial infarction (AMI).

METHODS: CMR was performed in 184 patients within the week following successfully reperfused first AMI. First-pass images were performed to evaluate extent of MO and late gadolinium-enhanced images to assess PMO and infarct size (IS). Major adverse cardiac events (MACE) were collected at 1-year follow-up.

RESULTS: MO and PMO were found in 127 (69%) and 87 (47%) patients, respectively. By using univariate logistic regression analysis, high Global Registry of Acute Coronary Events (GRACE) risk score (odds ratio [OR] 95% confidence interval [CI]: 3.6 [1.8-7.4], p < 0.001), IS greater than 10% (OR [95% CI]: 2.7 [1.1-6.9], p = 0.036), left ventricular ejection fraction less than 40% (OR [95% CI]: 2.4 [1.1-5.2], p = 0.027), presence of MO (OR [95% CI]: 3.1 [1.3-7.3], p = 0.004) and presence of PMO (OR [95% CI]:10 [4.1-23.9], p < 0.001) were shown to be significantly associated with the outcome. By using multivariate analysis, presence of MO (OR [95% CI]: 2.5 [1.0-6.2], p = 0.045) or of PMO (OR [95% CI]: 8.7 [3.6-21.1], p < 0.001), associated with GRACE score, were predictors of MACE.

CONCLUSIONS: Presence of microvascular obstruction and persistent microvascular obstruction is very common in AMI patients even after successful reperfusion and is associated with a dramatically higher risk of subsequent cardiovascular events, beyond established prognostic markers. Moreover, our data suggest that the prognostic impact of PMO might be superior to MO.

PMID: 19350245

Aug200904

Gian Novaro

1

Left Atrial Volume and Geometry in Healthy Aging: The Cardiovascular Health Study

Circulation. 2009; 2(6):282-289

Aurigemma GP, Gottdiener LS, Arnold AM, Chinali M, Hill JC, Kitzman D

OBJECTIVES:  The left atrium is a validated marker of clinical and subclinical cardiovascular disease. Left atrial enlargement is often seen among older individuals; however, there are few population-based data regarding normal left atrial size among older persons, especially from those who are healthy, and from women. Furthermore, because the left atrium is a 3D structure, the commonly used parasternal long-axis diastolic diameter often underdiagnoses left atrial enlargement.

METHODS: We evaluated left atrial size in 230 healthy participants (mean age, 76±5 years) free of prevalent cardiac disease, rhythm abnormality, hypertension, and diabetes selected from the Cardiovascular Health Study, a prospective community-based study of risk factors for cardiovascular disease in 5888 elderly participants. In addition to the standard long-axis measurement, we obtained left atrial superoinferior and lateral diameters and used these dimensions to estimate left atrial volume. These measurements were used to generate reference ranges for determining left atrial enlargement in older men and women, based on the 95% percentiles of the left atrial dimensions in healthy participants, both unadjusted, and after adjustment for age, height, and weight.

RESULTS: In healthy elderly subjects, indices of left atrial size do not correlate with age or height but with weight and other measures of body build.

CONCLUSIONS: These data provide normative reference values for left atrial size in healthy older women and men. The results should be useful for refining diagnostic criteria for left atrial dilation in the older population and may be relevant for cardiovascular risk stratification.

PMID:

Aug200903

Gian Novaro

1

The Pathophysiology of Heart Failure With Normal Ejection Fraction: Exercise Echocardiography Reveals Complex Abnormalities of Both Systolic and Diastolic Ventricular Function Involving Torsion, Untwist, and Longitudinal Motion

J Am Coll Cardiol. 2009; 54(1):36-46

Tan YT, Wenzelburger F, Lee E, Heatlie G, Leyva F, Patel K, Frenneaux M, Sanderson JE

OBJECTIVES: The purpose of this study was to test the hypothesis that in heart failure with normal ejection fraction (HFNEF) exercise limitation is due to combined systolic and diastolic abnormalities, particularly involving ventricular twist and deformation (strain) leading to reduced ventricular suction, delayed untwisting, and impaired early diastolic filling. Background: A substantial proportion of patients with heart failure have a normal left ventricular ejection fraction. Currently the pathophysiology is considered to be due to abnormal myocardial stiffness and relaxation.

METHODS: Patients with a diagnosis of HFNEF and proven cardiac limitation by cardiopulmonary exercise testing were studied by standard, tissue Doppler, and speckle tracking echocardiography at rest and on submaximal exercise.

RESULTS: Fifty-six patients (39 women; mean age 72 ± 7 years) with a clinical diagnosis of HFNEF and 27 age-matched healthy control subjects (19 women; mean age 70 ± 7 years) had rest and exercise images of sufficient quality for analysis. At rest, systolic longitudinal and radial strain, systolic mitral annular velocities, and apical rotation were lower in patients, and all failed to rise normally on exercise. Systolic longitudinal functional reserve was also significantly lower in patients (p < 0.001). In diastole, patients had reduced and delayed untwisting, reduced left ventricular suction at rest and on exercise, and higher end-diastolic pressures. Mitral annular systolic and diastolic velocities, systolic left ventricular rotation, and early diastolic untwist on exercise correlated with peak VO2max.

CONCLUSIONS: In HFNEF there are widespread abnormalities of both systolic and diastolic function that become more apparent on exercise. HFNEF is not an isolated disorder of diastole.

PMID: 19555838

Aug200903

Paul Schoenhagen

2

Incremental Prognostic Value of Multi-Slice Computed Tomography Coronary Angiography Over Coronary Artery Calcium Scoring in Patients with Suspected Coronary Artery Disease

Eur Heart J. 2009; 30(21):2622-2629

van Werkhoven JM, Schuijf JD, Gaemperli O, Jukema JW, Kroft LJ, Boersma E, Pazhenkottil A, Valenta I, Pundziute G, de Roos A, van der Wall EE, Kaufmann PA, Bax JJ

OBJECTIVES: The purpose of this study was to assess the relationship between calcium scoring (CS) and multi-slice computed tomography coronary angiography (MSCTA) and to determine if MSCTA has an incremental prognostic value to CS.

METHODS: In 432 patients (59% male, age 58 +/- 11 years) referred for cardiac evaluation owing to suspected coronary artery disease (CAD), CS and 64-slice MSCTA were performed. The following events were combined in a composite endpoint: all-cause mortality, non-fatal infarction, and unstable angina requiring revascularization.

RESULTS: CS was 0 in 147 (34%) patients, CS 1-99 was present in 122 (28%), CS 100-399 in 75 (17%), CS 400-999 in 56 (13%), and CS > 1000 in 32 (7%). MSCTA was normal in 133 (31%) patients, MSCTA 30-50% stenosis was observed in 190 (44%), and MSCTA > 50% stenosis in 109 (25%). During follow-up [median 670 days (25th-75th percentile: 418-895)], an event occurred in 21 patients (4.9%). After multivariate correction for CS, MSCTA > 50% stenosis, the number of diseased segments, obstructive segments, and non-calcified plaques were independent predictors with an incremental prognostic value to CS.

CONCLUSIONS: MSCTA provides additional information to CS regarding stenosis severity and plaque composition. This additional information was shown to translate into incremental prognostic value over CS.

PMID: 19567382