Cyclic changes in area- and perimeter-derived effective dimensions of the aortic annulus measured with multislice computed tomography and comparison with metric intraoperative sizing.

AIMS: Multislice computed tomography (MSCT) is recommended for annular sizing prior to transcatheter aortic valve implantation (TAVI), but it remains unclear whether systolic or diastolic reconstructions should be used and whether the effective annular diameter should be derived by area or perimeter. In this study these different approaches were compared with intraoperative sizing. METHODS: In 52 patients who were evaluated but deemed unsuitable for TAVI, the annulus was measured during conventional surgery using metric sizers (AnnOp) and compared with MSCT measurements (cross-sectional diameter derived by area [AnnAsys, AnnAdia; AnnAmean = (AnnAsys + AnnAdia)/2] and perimeter (AnnPsys, AnnPdia) in systole and diastole). Furthermore, TAVI was simulated based on AnnOp and the impact of the various MSCT approaches on sizing strategy was determined. RESULTS: The best agreement with AnnOp [mean difference (limits of agreement)] was shown for AnnAmean [0.03 mm (-1.9 to 1.96)], whereas the strongest deviation was noted for AnnPsys [-1.08 mm (-3.01 to 0.86)]. Mean differences between systole and diastole were significant but small: 0.82 mm (3.5 %) for area- and 0.81 mm (3.3 %) for perimeter-derived measurements. Simulation of TAVI revealed the least change of strategy for AnnAmean (76.9 %) as compared with AnnPsys (53.8 %); between AnnAsys and AnnAdia sizing would have been deviant in 17.3 % due to relatively large intraindividual cyclic differences. CONCLUSIONS: AnnAmean demonstrated the best agreement with AnnOp, whereas perimeter-derived measurements were somewhat overestimated. Despite a negligible average difference between systolic and diastolic annular values, in a subset of patients the intraindividual cyclic variability was relatively large and potentially of clinical impact.

Maladaptive hypertrophy after acute myocardial infarction positive effect of bone marrow-derived stem cell therapy on regional remodeling measured by cardiac MRI.

OBJECTIVE: In the aftermath of myocardial infarction, increased loading conditions will trigger hypertrophy of viable myocardium. This in turn causes deterioration of regional contractility. Cardiac magnetic resonance imaging (cMRI) allows the exact differentiation of viable and infarcted myocardium and therefore the measurement of regional wall thickness and function. Bone marrow-derived stem cell (BMC) transfer has been shown to improve global function and remodeling. The present study examines the effect of BMC transfer on regional remodeling and function after myocardial infarction by cMRI. DESIGN: Fifty-four patients of the MR substudy of the REPAIR-AMI trial have been studied at baseline and 12-month follow-up. Enddiastolic wall thickness (EDWT) and wall thickening (WT%) have been measured on SSFP cine sequences. RESULTS: Enddiastolic wall thickness decreased in both placebo and BMC groups in viable as well as infarcted segments. The effect was largest in the pre-specified subgroup of patients below the median EF of 48.9% (infarcted segments -1.14 mm Placebo vs. -1.91 mm BMC, p for interaction 0.01, remote segments -0.19 mm Placebo vs. -0.94 mm BMC, p for interaction 0.00001). Corrected for baseline values BMC therapy yielded smaller EDWT at 12 months in infarcted and remote segments (infarcted 7.58 mm Placebo vs. 6.13 mm BMC p = 0.0001, remote 8.76 mm Placebo vs. 7.32 mm BMC, p = 0.0001). This was associated with better contractility within the infarcted segments among BMC patients (WT% 24.17% Placebo vs. 49.31% BMC, p = 0.0001). The WT% was inversely correlated with EDWT (r = -0.37, p = 0.0001). CONCLUSION: Bone marrow-derived stem cell therapy yields smaller EDWT when compared with placebo patients suggesting a positive effect on maladaptive hypertrophy of viable myocardium. This notion is supported by the enhanced regional contractility within the BMC group which is inversely correlated with EDWT.

Intracoronary administration of bone marrow-derived progenitor cells improves left ventricular function in patients at risk for adverse remodeling after acute ST-segment elevation myocardial infarction: results of the Reinfusion of Enriched Progenitor cells And Infarct Remodeling in Acute Myocardial Infarction study (REPAIR-AMI) cardiac magnetic resonance imaging substudy.

BACKGROUND: Serial cardiac magnetic resonance imaging (CMR) is the reference standard for evaluating left ventricular function, wall motion, and infarct size in patients with acute myocardial infarction, as well as remodeling during follow-up. The cardiac CMR substudy of the randomized multicenter REPAIR-AMI trial (Reinfusion of Enriched Progenitor cells And Infarct Remodeling in Acute Myocardial Infarction study) aimed at gaining insight into postinfarction left ventricular remodeling processes. METHODS: Consecutive patients with ST-segment elevation myocardial infarction and primary percutaneous coronary intervention were enrolled (n = 204) and randomly assigned to either stem cell therapy (bone marrow-derived progenitor cells [BMC]) or placebo after bone marrow aspiration. In the magnetic resonance imaging substudy, 54 patients completed serial CMR (baseline, 4 and 12 months, respectively) after enrollment (27 BMC, 27 placebo). Image analysis was performed at a central core laboratory. RESULTS: There were no significant differences between the 2 groups with respect to global ejection fraction (EF), end-diastolic volume (EDV), and end-systolic volume (ESV) at baseline. At 12 months, the treatment effect of BMC infusion on EF amounted to 2.8 absolute percentage points (P = .26), the progression of EDV at 12 months was less in the BMC group (treatment effect 14 mL, P = .12), and unlike placebo, ESV did not increase (absolute treatment effect 13 mL, P = .08), respectively. In patients with a baseline EF < median (EF < or = 48.9%), BMC administration was associated with a significantly improved EF (+6.6%, P = .01), reduced EDV increase (treatment effect 29.1 mL, P = .02), and abrogation of ESV increase (treatment effect 29.4 mL, P = .01) after 12 months, respectively. CONCLUSION: Intracoronary administration of BMC additionally improved left ventricular function in patients with impaired left ventricular function after ST-segment elevation myocardial infarction despite optimal "state-of-the-art" reperfusion and pharmacologic treatment on 1-year follow-up and beneficially interfered with adverse postinfarction left ventricular remodeling.

Radiation dose exposure in multislice computed tomography of the coronaries in comparison with conventional coronary angiography.

BACKGROUND: Radiation dose exposure is increased in multislice spiral computed tomography (MSCT) compared to conventional coronary angiography (CXA). METHODS: Retrospective data analysis of 56 patients (66+/-8 years, 49 males, body surface area 1.98+/-0.18 m(2), heart rate 64+/-11 bpm) who underwent MSCT and CXA was performed (MSCT: 16-slice scanner, rotation time 0.375 s, 120 kV, ECG-pulsing; CXA: current technique system build in 2003). Ten patients with bypass grafts underwent bypass angiography in CXA and MSCT. To compare the radiation doses of both investigations, the effective dose (ED) was chosen as the analysis variable. RESULTS: The mean ED for MSCT was 9.76+/-1.84 mSv (n=46) for patients without bypass grafts; with calcium scoring the mean ED was 12.46+/-2.23 mSv (n=46). In comparison, the mean ED of CXA was 2.60+/-1.27 mSv (n=46) for patients without bypass grafts; with bypass grafts (n=10) the mean ED for MSCT was 12.95+/-1.75 mSv, for CXA of 6.27+/-4.04 mSv, respectively. In MSCT heart rates of 60 bpm (8.86+/-1.24 mSv versus 10.53+/-1.86 mSv). CONCLUSIONS: MSCT is still associated with a higher radiation dose exposure than CXA. The radiation dose relation is more favorable for MSCT than for CXA in patients with bypass grafts in comparison to patients without bypass grafts. This study emphasizes the importance of dose reduction techniques.

Use of automatic exposure control in multislice computed tomography of the coronaries: comparison of 16-slice and 64-slice scanner data with conventional coronary angiography.

OBJECTIVE: To evaluate the radiation-dose-reduction potential of automatic exposure control (AEC) in 16-slice and 64-slice multislice computed tomography (MSCT) of the coronary arteries (computed tomography angiography, CTA) in patients. The rapid growth in MSCT CTA emphasises the necessity of adjusting technique factors to reduce radiation dose exposure. DESIGN: A retrospective data analysis was performed for 154 patients who had undergone MSCT CTA. Group 1 (n = 56) had undergone 16-slice MSCT without AEC, and group 2 (n = 51), with AEC. In group 1, invasive coronary angiography (ICA) had been performed in addition. Group 3 (n = 47) had been examined using a 64-slice scanner (with AEC, without ECG-triggered tube current modulation). RESULTS: In group 1, the mean (SD) effective dose (ED) for MSCT CTA was 9.76 (1.84) mSv and for ICA it was 2.6 (1.27) mSv. In group 2, the mean ED for MSCT CTA was 5.83 (1.73) mSv, which signifies a 42.8% dose reduction for CTA by the use of AEC. In comparison to ICA, MSCT CTA without AEC shows a 3.8-fold increase in radiation dose, and the radiation dose of CTA with AEC was increased by a factor of 1.9. In group 3, the mean ED for MSCT CTA was 13.58 (2.80) mSV. CONCLUSIONS: This is the first study to show the significant dose-reduction potential (42.8%) of AEC in MSCT CTA in patients. This relatively new technique can be used to optimise the radiation dose levels in MSCT CTA.

Diagnostic value of the 16-detector row multislice spiral computed tomography for the detection of coronary artery stenosis in comparison to invasive coronary angiography.

OBJECTIVES: The aim of this study was to determine the diagnostic accuracy of 16-slice multislice spiral computed tomography (MSCT) of the coronaries and to provide data in a real clinical setting. Previous 16-slice MSCT studies presented data excluding patients with calcification, vessels of < 1.5 or 2 mm, and segments with impaired image quality. By including these data for 16-slice MSCT, a direct comparison with new data from 64-slice MSCT is possible. METHODS AND RESULTS: Sixty two patients with suspected or known coronary artery disease (CAD) were prospectively enrolled and underwent computed tomography angiography (CTA) and invasive coronary angiography (ICA). All vessels were evaluated for the presence of a significant coronary artery stenosis (>50%) using the American Heart Association (AHA) 15-segment model. From the evaluation of 917 segments, sensitivity, specificity, and positive and negative predictive value (NPV) (positive predictive value [PPV] and NPV) for the presence of relevant coronary stenosis were 73, 98, and 71 and 98% per segment and 94, 90, and 91 and 93% per patient, respectively. The influence of age, gender, body surface area (BSA), heart rate (HR), stents, and Ca(2+)-score value was analyzed. High Ca(2+)-score values were the only statistically significant predictor for impaired diagnostic accuracy. CONCLUSIONS: In summary, CTA with evaluation of all vessel segments in a broad spectrum of patients allowed accurate and fast noninvasive coronary artery evaluation, including evaluation of stented segments. These data are very similar to those published recently for 64-slice scanners.

Contractile effects of angiotensin and endothelin in failing and non-failing human hearts.

BACKGROUND: Angiotensin II (Ang II) and endothelin-1 (ET-1) share their effects on growth of myocardial cells but have been shown to elicit different effects on myocardial function. However, these effects vary markedly among species, cardiac regions (atrium or ventricle) and failing or non-failing myocardium. We therefore investigated the effects of both peptides on contractile function of isolated human myocytes from failing and non-failing hearts. METHODS AND RESULTS: Cardiomyocytes were enzymatically isolated and electrically stimulated (15 V, 0.2 Hz). Ang II elicited a positive inotropic effect (PIE) mediated by activation of protein kinase C (PKC) in atrial but no effect in ventricular myocytes. ET-1 (10(-8) M) increased cell-shortening by 146+/-9.3% (p<0.05) in atrial myocytes, by 99.1+/-16.5% (p<0.05) in non-failing ventricular but only by 40.5+/-6.4% (p<0.05) in failing ventricular myocytes. The PIE of ET-1 in failing myocytes was more pronounced at low extracellular pH (+112.6+/-27% at pH 7.0 vs. +40.5+/-6.4% at pH 7.4, p<0.05). Amiloride, a sodium-hydrogen-exchange inhibitor, inhibited two thirds of the PIE of ET-1 in failing myocytes. The PKC-inhibitor decreased the PIE by 50% from 113% to 64% in ventricular myocytes under acidotic conditions. CONCLUSION: Ang II and ET-1 elicited PIE in atrial myocytes, whereas in ventricular myocytes Ang II did not induce PIE in contrast to ET-1. The PIE of ET-1 was markedly attenuated in failing myocytes. Under acidotic conditions, the PIE of ET-1 was more pronounced in failing myocytes, indicating that ET-1 may activate signaling processes in failing myocytes, which are not activated in normal myocytes.

Primary stenting of the left main coronary artery with anomalous origin from the right sinus of valsalva.

The presence of an aberrant origin of left main coronary artery from the right sinus of valsalva passing between the aorta ascendens and pulmonary trunk is one of the anomalies most frequently associated with malignant clinical events, and surgical treatment is recommended. We report of a 64-year-old patient with a highly increased risk for surgery due to severe chronic obstructive pulmonary disease. This case demonstrates that the use of a drug-eluting stent offers a suitable and valuable alternative.

Value of gadolinium-enhanced magnetic resonance imaging in patients with Tako-Tsubo-like left ventricular dysfunction.

We present gadolinium-enhanced cardiac magnetic resonance imaging (CMRI) in Tako-Tsubo-like left ventricular dysfunction showing the findings in acute phase and in follow-up. Gadolinium-enhanced CMRI allows to distinguish between myocardial infarction and other myocardial alterations, e.g., myocarditis. CMRI may thus permit to non-invasively identify patients with Tako-Tsubo syndrome by ruling out myocardial infarction or myocarditis in the setting of wall motion abnormalities (WMA).

Cardiac angiosarcoma diagnosed and characterized by cardiac magnetic resonance imaging.

Primary cardiac malignancies are rare. New imaging methods like cardiac magnetic resonance imaging (MRI) play an important role in the early diagnosis and differentiation of cardiac masses. By presenting the case of a 63-year-old woman with an angiosarcoma of the right atrium and its characteristic findings on cardiac MRI, the role of this new imaging method is emphasized.

Kinetics of insulin adsorption at the oil-water interface and diffusion properties of adsorbed layers monitored using fluorescence correlation spectroscopy.

The adsorption of insulin at an oil-water interface was studied with fluorescence correlation spectroscopy (FCS). FCS is able to measure diffusion properties of insulin at nanomolar concentrations, making it possible to detect the very early steps in the adsorption process. Below 20 nM bulk insulin concentration, the insulin molecules adsorbed to the surface diffuse freely at all times during the experiment (a few hours). At higher concentrations, a surprisingly abrupt transition to a slow diffusion phase is observed. Based on the information about both diffusion times and molecular brightness derived from the FCS experiments, we suggest that the transition represents the formation of a fractal network. FCS may be a valuable tool in pharmaceutical formulation science, because it provides information about concentration buildup and phase changes at interfaces formed in drug delivery systems.

Interfacial adsorption of insulin conformational changes and reversibility of adsorption.

The adsorption of human insulin to Teflon particles was studied with respect to conformational changes and the reversibility of adsorption was examined by total internal reflection fluorescence (TIRF). Adsorption isotherms for the adsorption of human insulin indicated high affinity adsorption, even at electrostatic repulsive conditions. The plateau value for adsorption was in accordance with a protein layer consisting primarily of insulin monomers. Conformational changes of the insulin upon adsorption, was investigated by circular dicroism (CD) and fluorescence spectroscopy. The results suggested unfolding of adsorbed insulin, as observed by a decrease in alpha-helix and increase in random coil conformation. The changes in protein structure was not only related to the adsorbed species being monomeric, since CD and fluorescence results were different for adsorbed insulin compared to a monomeric analog of human insulin. Furthermore, the thermal stability in the adsorbed state was changed compared to insulin in solution. On the basis of the TIRF studies with FITC-labelled insulin it was not possible to firmly conclude whether exchange between human insulin in the adsorbed state and in solution takes place, due to the limited time range investigated. However, the desorption mechanism appeared to be different with unlabelled insulin in the bulk solution compared to phosphate buffer.