JACC Cardiovasc Interv. . 2010; 3(821-7):82

Ntalianis A, Trana C, Muller O, Mangiacapra F, Peace A, De Backer C, De Block L, Wyffels E, Bartunek J, Vanderheyden M, Heyse A, Van Durme F, Van Driessche L, De Jans J, Heyndrickx GR, Wijns W, Barbato E, De Bruyne B.

OBJECTIVES: This study sought to define the additional effective radiation dose, procedural time, and contrast medium needed to obtain fractional flow reserve (FFR) measurements after a diagnostic coronary angiogram.

BACKGROUND: The FFR measurements performed at the end of a diagnostic angiogram allow the obtaining of functional information that complements the anatomic findings.

METHODS: In 200 patients (mean age 66 +/- 10 years) undergoing diagnostic coronary angiography, FFR was measured in at least 1 intermediate coronary artery stenosis. Hyperemia was achieved by intracoronary (n = 180) or intravenous (n = 20) adenosine. The radiation dose (mSv), procedural time (min), and contrast medium (ml) needed for diagnostic angiography and FFR were recorded.

RESULTS: A total of 296 stenoses (1.5 +/- 0.7 stenoses per patient) were assessed. The additional mean radiation dose, procedural time, and contrast medium needed to obtain FFR expressed as a percentage of the entire procedure were 30 +/- 16% (median 4 mSv, range 2.4 to 6.7 mSv), 26 +/- 13% (median 9 min, range 7 to 13 min), and 31 +/- 16% (median 50 ml, range 30 to 90 ml), respectively. The radiation dose and contrast medium during FFR were similar after intravenous and intracoronary adenosine, though the procedural time was slightly longer with intravenous adenosine (median 11 min, range 10 to 17 min, p = 0.04) than with intracoronary adenosine (median 9 min, range 7 to 13 min). When FFR was measured in 3 or more lesions, radiation dose, procedural time, and contrast medium increased.

CONCLUSIONS: The additional radiation dose, procedural time, and contrast medium to obtain FFR measurement are low as compared to other cardiovascular imaging modalities. Therefore, the combination of diagnostic angiography and FFR measurements is warranted to provide simultaneously anatomic and functional information in patients with coronary artery disease.

PMID: 20723854

J Am Coll Cardiol. 2010; 56(8):617-626

Van Mieghem NM, Piazza N, Anderson RH, Tzikas A, Nieman K, De Laat LE, McGhie JS, Geleijnse ML, Feldman T, Serruys PW, de Jaegere PP

Mitral regurgitation (MR) poses a significant clinical burden in the adult population, which is expected to increase even more with the ever prolonging life expectancies in developed countries. New technology has brought MR, once exclusively the arena of cardiac surgeons, to the attention of interventional cardiologists. A variety of device-oriented transcatheter strategies have evolved in recent years. A comprehensive understanding of mitral valvular anatomy is crucial for the selection of patients, the implementation of devices, and further refinements of these transcatheter techniques if they are eventually to produce procedural and clinical success. The aim of this review is to elucidate the morphology of the mitral valvular complex, integrating key anatomical features into the developing transcatheter options for the treatment of MR.

PMID: 20705218

Circulation. 2010; 122(9):884-890

Lam CS, Xanthakis V, Sullivan LM, Lieb W, Aragam J, Redfield MM, Mitchell GF, Benjamin EJ, Vasan RS

OBJECTIVES: Aortic root remodeling in adulthood is known to be associated with cardiovascular outcomes. However, there is a lack of longitudinal data defining the clinical correlates of aortic root remodeling over the adult life course.

METHODS: We used serial routine echocardiograms in participants of the Framingham Heart Study to track aortic root diameter over 16 years in mid to late adulthood and to determine its short-term (4 years; n=6099 observations in 3506 individuals) and long-term (16 years; n=14 628 observations in 4542 individuals) clinical correlates by multilevel modeling. Age, sex, body size, and blood pressure were principal correlates of aortic remodeling in both short- and long-term analyses (all P<0.01).

RESULTS: Aortic root diameter increased with age in both men and women but was larger in men at any given age. Each 10-year increase in age was associated with a larger aortic root (by 0.89 mm in men and 0.68 mm in women) after adjustment for body size and blood pressure. A 5-kg/m(2) increase in body mass index was associated with a larger aortic root (by 0.78 mm in men and 0.51 mm in women) after adjustment for age and blood pressure. Each 10-mm Hg increase in pulse pressure was related to a smaller aortic root (by 0.19 mm in men and 0.08 mm in women) after adjustment for age and body size.

CONCLUSIONS: These longitudinal community-based data show that aortic root remodeling occurs over mid to late adulthood and is principally associated with age, sex, body size, and blood pressure. The underlying basis for these differences and implications for the development of cardiovascular events deserve further study.

PMID: 20713896

American Journal or Roentgenology. 2010; 195(3):655661

Jonathon Leipsic, Troy M. LaBounty, Brett Heilbron, James K. Min, G. B. John Mancini, Fay Y. Lin, Carolyn Taylor, Allison Dunning, James P. Earls

OBJECTIVES: The objective of our study was to assess the impact of Adaptive Statistical Iterative Reconstruction (ASIR) on radiation dose and study quality for coronary CT angiography (CTA).

METHODS: We prospectively evaluated 574 consecutive patients undergoing coronary CTA at three centers. Comparisons were performed between consecutive groups initially using filtered back projection (FBP) (n = 331) and subsequently ASIR (n = 243) with regard to patient and scan characteristics, radiation dose, and diagnostic study quality.

RESULTS: There was no difference between groups in the use of prospective gating, tube voltage, or scan length. The examinations performed using ASIR had a lower median tube current than those obtained using FBP (median [interquartile range], 450 mA [350–600] vs 650 mA [531–750], respectively; p < 0.001). There was a 44% reduction in the median radiation dose between the FBP and ASIR cohorts (4.1 mSv [2.3–5.2] vs 2.3 mSv [1.9–3.5]; p < 0.001). After adjustment for scan settings, ASIR was associated with a 27% reduction in radiation dose compared with FBP (95% CI, 21–32%; p < 0.001). Despite the reduced current, ASIR was not associated with a difference in adjusted signal, noise, or signal-to-noise ratio (p = not significant). No differences existed between FBP and ASIR for interpretability per coronary artery (98.5% vs 99.3%, respectively; p = 0.12) or per patient (96.1% vs 97.1%, p = 0.65).

CONCLUSIONS: ASIR enabled reduced tube current and lower radiation dose in comparison with FBP, with preserved signal, noise, and study interpretability, in a large multicenter cohort. ASIR represents a new technique to reduce radiation dose in coronary CTA studies.

PMID:

Eur Heart J. 2010; 31(16):678-681

Andy S.C. Yong, Austin C.C. Ng, David Brieger, Harry C. Lowe, Martin K.C. Ng, Leonard Kritharides

OBJECTIVES: We investigated whether three-dimensional (3D) and two-dimensional quantitative coronary angiography (2D-QCA) measurements differed in their accuracy in predicting reduced fractional flow reserve (FFR), and how this varied with stenosis severity and the FFR cut-off used.

METHODS:  Three-dimensional and 2D-QCA were compared in their measurements of minimum luminal area (MLA), percentage area stenosis, lesion length, minimum luminal diameter (MLD) and percentage diameter stenosis, and in their prediction of functionally significant FFR.

OBJECTIVES: In total, 63 target lesions were interrogated in 63 patients undergoing elective percutaneous coronary intervention. Of all measurements of lesion severity obtained by 3D-QCA, MLA best correlated with FFR (R = 0.63, P< 0.001), and was the most accurate predictor of FFR <0.75 (C statistic 0.86, P< 0.001). Of 2D-QCA measurements, MLD correlated best with FFR (R = 0.58, P< 0.001), and best predicted FFR <0.75 (C statistic 0.80, P<0.001). Overall, 3D-QCA showed a non-significant trend towards more accurate prediction of FFR than 2D-QCA, especially in intermediate lesions. The relationship between FFR and apparent stenosis severity was found to be curvilinear. Both 3D- and 2D-QCA were less accurate in intermediate lesions, and in predicting FFR ≤0.80 than in predicting FFR <0.75.

PMID:

J Am Coll Cardiol Img . 2010; 3():811-820

Kheng-Thye Ho, Kia-Chong Chua, Ernst Klotz, Christoph Panknin

OBJECTIVES: This study sought to describe a protocol for myocardial perfusion imaging using dipyridamole stress, with 128-slice dual-source computed tomography (CT), and to assess the ability of CT myocardial perfusion imaging (MPI) to detect abnormal flow reserve and infarction in comparison with nuclear MPI (NMPI). CT MPI has not been previously described with the 128-slice dual-source CT scanner, or with the complete evaluation of dynamic time-attenuation curves of the myocardium.

METHODS: Thirty-five patients underwent a stress CT MPI protocol. Complete time-attenuation curves of the myocardium were acquired using a novel scan mode, which acquires prospectively electrocardiogram (ECG)-triggered axial images at 2 rapidly alternating positions. Myocardial blood flow (MBF) values of fixed and reversible defects obtained were compared between rest and stress. Findings on CT MPI were correlated to NMPI. Perfusion defects detected on CT were correlated to coronary stenoses detected on CT angiography (CTA) and invasive coronary angiography (ICA).

RESULTS: There was a 1.5-fold difference between stress (1.21 ± 0.31 cc/cc/min) and rest (0.82 ± 0.22 cc/cc/min) MBF in normal tissue. In reversible defects, MBF was 0.65 ± 0.21 cc/cc/min and 0.63 ± 0.18 cc/cc/min at stress and rest, respectively. In fixed defects, the MBF was 0.57 ± 0.22 cc/cc/min at stress and 0.54 ± 0.23 cc/cc/min at rest. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT MPI for identifying segments with perfusion defects was 0.83, 0.78, 0.79, and 0.82, respectively. ICA results were available for 30 patients. Sensitivity, specificity, PPV, and NPV of CT MPI compared with ICA were 0.95, 0.65, 0.78, and 0.79, respectively. The radiation dose for CT MPI was 9.15 ± 1.32 mSv for the stress scan and 9.09 ± 1.40 mSv for the rest scan.

CONCLUSIONS: Vasodilator-stress CT MPI may be feasible in human subjects at a radiation dose similar to NMPI. It identifies areas of abnormal flow reserve and infarction with a high degree of correlation to NMPI as well as to stenoses detected in CTA and ICA.

PMID:

Int J Cardiovasc Imaging. 2010; 26(6):567-569

Nagao M, Kido T, Watanabe K, Saeki H, Okayama H, Kurata A, Hosokawa K, Higashino H, Mochizuki T

OBJECTIVES: We attempted to assess coronary artery flow using adenosine-stress and dual-energy mode with dual-source CT (DE-CT).

METHODS: Data of 18 patients with suspected coronary arteries disease who had undergone cardiac DE-CT were retrospectively analyzed. The patients were divided into two groups: 10 patients who performed adenosine stress CT, and 8 patients who performed rest CT as controls. We reconstructed an iodine map and composite images at 120 kV (120 kV images) using raw data with scan parameters of 100 and 140 kV. We measured mean attenuation in the coronary artery proximal to the distal portion on both the iodine map and 120 kV images. Coronary enhancement ratio (CER) was calculated by dividing mean attenuation in the coronary artery by attenuation in the aortic root, and was used as an estimate of coronary enhancement. Coronary stenosis was identified as a reduction in diameter of >50% on CT angiogram, and myocardial ischemia was diagnosed by adenosine-stress myocardial perfusion scintigraphy.

RESULTS: The iodine map showed that CER was significantly lower for ischemic territories (0.76 +/- 0.06) or stenosed coronary arteries (0.77 +/- 0.06) than for non-ischemic territories (0.95 +/- 0.21, P = 0.02) or non-stenosed coronary arteries (1.07 +/- 0.33, P < 0.001). The 120 kV images showed no difference in CER between these two groups. Use of CER on the iodine map separated ischemic territories from non-ischemic territories with a sensitivity of 86% and a specificity of 75%.

CONCLUSIONS: Our quantification is the first non-invasive analytical technique for assessment of coronary artery flow using cardiac CT. CER on the iodine map is a candidate method for demonstration of alteration in coronary artery flow under adenosine stress, which is related to the physiological significance of coronary artery disease.

PMID: 20686853

Eur Radiol. 2010; 20(9):1045-1054

Karlo C, Leschka S, Goetti RP, Feuchtner G, Desbiolles L, Stolzmann P, Plass A, Falk V, Marincek B, Alkadhi H, Baumüller S

OBJECTIVES: To compare image quality and radiation dose of high-pitch computed tomography angiography(CTA) of the aortic valve-aortic root complex with and without prospective ECG-gating compared to a retrospectively ECG-gated standard-pitch acquisition.

METHODS: 120 patients(mean age 68 +/- 13 years) were examined using a 128-slice dual-source CT system using prospectively ECG-gated high-pitch(group A; n = 40), non-ECG-gated high-pitch(group B; n = 40) or retrospectively ECG-gated standard-pitch(C; n = 40) acquisition techniques. Image quality of the aortic root, valve and ascending aorta including the coronary ostia was assessed by two independent readers. Image noise was measured, radiation dose estimates were calculated.

RESULTS: Interobserver agreement was good(kappa = 0.64-0.78). Image quality was diagnostic in 38/40 patients(group A), 37/40(B) and 38/40(C) with no significant difference in number of patients with diagnostic image quality among all groups (p = 0.56). Significantly more patients showed excellent image quality in group A compared to groups B and C(each, p < 0.01). Average image noise was significantly different between all groups(p < 0.05). Mean radiation dose estimates in groups A and B(each; 2.4 +/- 0.3 mSv) were significantly lower compared to group C(17.5 +/- 4.4 mSv; p < 0.01).

CONCLUSIONS: High-pitch dual-source CTA provides diagnostic image quality of the aortic valve-aortic root complex even without ECG-gating at 86% less radiation dose when compared to a standard-pitch ECG-gated acquisition.

PMID: 20677006

Radiology. 2010; 256(2):456-457

Cormode DP, Roessl E, Thran A, Skajaa T, Gordon RE, Schlomka JP, Fuster V, Fisher EA, Mulder WJ, Proksa R, Fayad ZA

OBJECTIVES: To investigate the potential of spectral computed tomography (CT) (popularly referred to as multicolor CT), used in combination with a gold high-density lipoprotein nanoparticle contrast agent (Au-HDL), for characterization of macrophage burden, calcification, and stenosis of atherosclerotic plaques.

METHODS: The local animal care committee approved all animal experiments. A preclinical spectral CT system in which incident x-rays are divided into six different energy bins was used for multicolor imaging. Au-HDL, an iodine-based contrast agent, and calcium phosphate were imaged in a variety of phantoms. Apolipoprotein E knockout (apo E-KO) mice were used as the model for atherosclerosis. Gold nanoparticles targeted to atherosclerosis (Au-HDL) were intravenously injected at a dose of 500 mg per kilogram of body weight. Iodine-based contrast material was injected 24 hours later, after which the mice were imaged. Wild-type mice were used as controls. Macrophage targeting by Au-HDL was further evaluated by using transmission electron microscopy and confocal microscopy of aorta sections.

RESULTS: Multicolor CT enabled differentiation of Au-HDL, iodine-based contrast material, and calcium phosphate in the phantoms. Accumulations of Au-HDL were detected in the aortas of the apo E-KO mice, while the iodine-based contrast agent and the calcium-rich tissue could also be detected and thus facilitated visualization of the vasculature and bones (skeleton), respectively, during a single scanning examination. Microscopy revealed Au-HDL to be primarily localized in the macrophages on the aorta sections; hence, the multicolor CT images provided information about the macrophage burden.

CONCLUSIONS: Spectral CT used with carefully chosen contrast agents may yield valuable information about atherosclerotic plaque composition.

PMID: 20668118

Circ Cardiovasc Imaging. 2010; 3(4):351-359

Russo V, Zavalloni A, Bacchi Reggiani ML, Buttazzi K, Gostoli V, Bartolini S, Fattori R

OBJECTIVES: Multidetector CT coronary angiography (MDCTCA) is capable of detecting coronary artery disease (CAD) with a high diagnostic accuracy. In particular, this technique is credited with having a negative predictive value close to 100%. However, data about the prognostic value of MDCTCA are currently lacking. We sought to determine the prognostic value of MDCTCA in patients with suspected but undocumented CAD and, in particular, the incremental prognostic value as compared with clinical risk and calcium scoring.

METHODS: A total of 441 patients (age, 59.7+/-11.6 years) with suspected CAD underwent MDCTCA to evaluate the presence and severity of the disease. Patients were followed up as to the occurrence of hard cardiac events (cardiac death, nonfatal myocardial infarction, and unstable angina requiring hospitalization).

RESULTS: Coronary lesions were detected in 297 (67.3%) patients. During a mean follow-up of 31.9+/-14.8 months, 44 hard cardiac events occurred in 40 patients. CT calcium scoring showed a statistically significant incremental prognostic value as compared to a baseline clinical risk model (P=0.018), whereas MDCTCA provided an additional incremental prognostic value as compared with a baseline clinical risk model plus calcium scoring if considering both nonobstructive versus obstructive CAD (P=0.016) or, better, plaque composition (calcified versus noncalcified and/or mixed plaques, P=0.0001). During follow-up, an excellent prognosis was noted in patients with normal coronary arteries, with an annualized incidence rate of 0.88% if compared with those with mild CAD (3.89%) and with patients with significant coronary disease (8.09%). The presence of noncalcified or mixed plaques, regardless of lesion severity, was found to be the strongest predictor of events (P<0.0001) as a potential marker of plaque vulnerability.

CONCLUSIONS: MDCTCA provides independent and incremental prognostic information as compared to baseline clinical risk factors and calcium scoring in patients with suspected CAD.

PMID: 20460497