Accuracy of VO2 estimation according to the widely used Krakau formula for the prediction of cardiac output.

BACKGROUND: Invasive cardiac output (CO) is measured with the thermodilution (TD) or the indirect Fick method (iFM) in right heart catheterization (RHC). The iFM estimates CO using approximation formulas for oxygen consumption ([Formula: see text]O2), but there are significant discrepancies (> 20%) between both methods. Although regularly applied, the formula proposed by Krakau has not been validated. We compared the CO discrepancies between the Krakau formula with the reference (TD) and three established formulas and investigated whether alterations assessed in cardiac magnetic resonance imaging (CMR) determined the extent of the deviations. METHODS: This retrospective study included 188 patients aged 63 ± 14 years (30% women) receiving both CMR and RHC. The CO was measured with TD or with the iFM using the formulas by Krakau, LaFarge, Dehmer, and Bergstra for [Formula: see text]O2 estimation (iFM-K/-L/-D/-B). Percentage errors were calculated as twice the standard deviation of the difference between two CO methods divided by their means; a cut-off of < 30% was regarded as acceptable. The iFM and TD-derived CO ratio was built, and deviations > 20% were counted. Logistic regression analyses were performed to identify determinants of a deviation of > 20%. RESULTS: The TD-derived CO (5.5 ± 1.7 L/min) was significantly different from all iFM (K: 4.8 ± 1.6, L: 4.3 ± 1.6; D: 4.8 ± 1.5 L/min; B: 5.4 ± 1.8 L/min all p < 0.05). The iFM-K-CO differed from all methods (p < 0.001) except iFM­D (p = 0.19). Percentage errors between TD-CO and iFM-K/-L/-D/-B were all beyond the acceptance limit (44/45/44/43%), while percentage errors between iFM­K and other iFM were all < 16%. None of the parameters measured in CMR was predictive of a discrepancy of > 20% between both methods. CONCLUSION: The Krakau formula was comparable to other iFM in estimating CO levels, but none showed satisfactory agreement with the TD method. Improved derivation cohorts for [Formula: see text]O2 estimation are needed that better reflect today's patients undergoing RHC.

CMR detects extensive intracavitary thrombi as solitary clinical presentation of Antiphospholipid Syndrome: A case report.

Intracavitary thrombi are an important differential diagnosis of cardiac masses. Cardiac magnetic resonance imaging (CMR) allows their non-invasive characterization. This case highlights extensive cardiac thrombi detected by CMR as solitary presentation of antiphospholipid syndrome.

A randomized controlled trial of simulation training in teaching coronary angiographic views.

INTRODUCTION: Simulation technology has an established role in teaching technical skills to cardiology fellows, but its impact on teaching trainees to interpret coronary angiographic (CA) images has not been systematically studied. The aim of this randomized controlled study was to test whether structured simulation training, in addition to traditional methods would improve CA image interpretation skills in a heterogeneous group of medical trainees. METHODS: We prospectively randomized a convenience sample of 105 subjects comprising of medical students (N = 20), residents (N = 68) and fellows (N = 17) from the University of Arizona. Subjects were randomized in a stratified fashion into a simulation training group which received simulation training in addition to didactic teaching (n = 53) and a control training group which received didactic teaching alone (n = 52). The change in pre and post-test score (delta score) was analyzed by a two-way ANOVA for education status and training arm. RESULTS: Subjects improved in their post-test scores with a mean change of 4.6 ± 4.0 points. Subjects in the simulation training arm had a higher delta score compared to control (5.4 ± 4.2 versus 3.8 ± 3.7, p = 0.04), with greatest impact for residents (6.6 ± 4.0 versus 3.5 ± 3.4) with a p = 0.02 for interaction of training arm and education status. CONCLUSIONS: Simulation training complements traditional methods to improve CA interpretation skill, with greatest impact on residents. This highlights the importance of incorporating high-fidelity simulation training early in cardiovascular fellowship curricula.

A Skill Trainer for Balloon/Stent Exchange in Percutaneous Coronary Intervention-Concept and Evaluation.

BACKGROUND: To prevent complications, uncontrolled movement of the guidewire during a coronary intervention should be avoided. Unintentional withdrawal of the wire can result in the inability to recross a lesion with the risk of myocardial infarction. On the other hand, unintended forward pushing can lead to a coronary perforation. Thus, interventionalists in training should practice keeping the coronary guidewire in a stable position to prevent complications. For this purpose, a skill trainer has been developed, which provides the possibility of unlimited practice outside of the cath lab.The purpose of this study was to assess the effectiveness and the validity of this skills trainer. METHODS: Ten novices and 10 participants with experience in diagnostic catheterization underwent training on the skills trainer consisting of 25 procedures. To assess the efficacy of the training module, the mean score of the first 3 procedures was compared with the final 3 procedures in the novice and the advanced group. To determine the construct validity of the simulator, a group of experts (E; performed >1000 percutaneous coronary interventions) also underwent evaluation on the skills trainer. For each procedure, the change in position of the guidewire as well as the time was determined and combined into a skills score with a maximum of 15 points. RESULTS: The novice and the advanced group improved significantly throughout the training on the simulator (N: 7.1 ± 2.6 to 12.2 ± 2.0, P = 0.007; A: 8.3 ± 2.0 to 13.2 ± 1.0, P = 0.005, Wilcoxon).The experts scored significantly higher than novices or the advanced participants during their first 3 procedures (E: 12.9 ± 1.0; N: 7.1 ± 2.6, P = 0.001; A: 8.3 ± 2.0, P = 0.001; Mann-Whitney U ). CONCLUSIONS: This low-cost task trainer is a valid and effective tool to train adequate balloon/stent exchange while keeping the guidewire in a stable position. Whether the skills acquired on the task trainer can be transferred to procedures performed on patients needs further investigation.

Interventional closure of aortomitral perforation after TAVR: A case report.

Despite TAVR emerging as the gold standard for a broad spectrum of patients, it is associated with serious complications. In this report we present a case, where a TAVR procedure led to a perforation at the aortomitral continuity, discuss the risk factors for the occurrence of perforations and how we decided to treat the patient.

Myocardial Fibrosis Predicts 10-Year Survival in Patients Undergoing Aortic Valve Replacement.

Background Long-term data on evolution and clinical impact of myocardial fibrosis in valvular heart disease are scarce. Methods and Results In this 10 years' extension of a prospective study in patients undergoing conventional aortic valve replacement because of symptomatic severe aortic valve stenosis, the impact of myocardial replacement fibrosis (MRF) on long-term outcome was assessed. Endomyocardial biopsies were acquired during aortic valve replacement in 58 consecutive patients. MRF was graded using the calculated percentage area of fibrosis and patients categorized as severe (n=21), mild (n=15), and no fibrosis (n=22). Echocardiography including strain imaging, as well as cardiovascular magnetic resonance, to assess late gadolinium enhancement was performed at baseline, 1, and 10 years after aortic valve replacement. Death of any cause occurred in 21 patients (38.9%): 3 (14.3%) in the group without MRF, 6 (42.9%) in the mild MRF group, and 12 (63.2%) in the severe MRF group ( P=0.006), resulting in the lowest cumulative survival for patients with severe MRF (log-rank P=0.003). In the group without MRF, none died of cardiovascular cause. MRF was found to be an independent predictor of survival (hazard ratio, 1.271; 95% CI, 1.032-1.564; P=0.024). Conclusions This 10-year follow-up study underlines the profound impact of replacement fibrosis with regard to cardiac and all-cause mortality in patients undergoing aortic valve replacement for severe aortic valve stenosis. Integrating cardiovascular magnetic resonance and echocardiographic functional imaging beyond ejection fraction quantification could help in clinical decision making to stratify patient prognosis with regard to myocardial longitudinal function and prevalence of replacement fibrosis.

"Blind" pericardiocentesis: A comparison of different puncture directions.

BACKGROUND: "Blind" pericardiocentesis is the standard procedure for emergency pericardial drainage when ultrasound guidance is unavailable. Under these circumstances, puncture site and needle direction are exclusively oriented according to certain anatomic landmarks. In the literature, different techniques for this "blind" method have been described. Goal of this retrospective study was to compare the potential success and complication rate of 13 simulated puncture directions. METHODS: Simulated pericardiocentesis was performed in 150 CT scans from patients with moderate to severe pericardial effusions (greater than 1 cm distance between epicardium and pericardium). Thirteen different puncture techniques with varying puncture sites, direction of the puncture, and the angle were compared. A simulated pericardiocentesis was classified as "successful" when the effusion was reached. It was classified as "successful without a complication" when no adjacent structure was penetrated by the simulated puncture (lung, liver, internal thoracic artery, LAD, colon, and stomach). An attempt was declared as "unsuccessful" when the pericardial effusion was not reached at all, or the reached effusion measured less than 0.5 cm between the epicardium and pericardium at the location where the needle entered the pericardium. RESULTS: A subxiphoidal puncture technique starting in Larrey's triangle (sternocostal triangle) and directed toward the left midclavicular point with a 30° inclination resulted in the highest success rate (131 of 150 cases = 87%). In parallel the lowest complication rate (7 of 150 = 5%) was found using this technique, as well. In contrast, pericardiocentesis performed using other puncture directions resulted in lower success (66%-85%) and higher complication rates (9%-31%). CONCLUSION: This CT-based simulation study revealed that blind pericardiocentesis guided by anatomical landmarks only is best performed in a subxiphoid approach with a needle direction to the left midclavicular point with a 30° inclination. Nevertheless, injury of adjacent structures occurred frequently (5%) even when applying this puncture technique. Thus, blind pericardiocentesis can be performed with a high success rate and seems adequate to be performed under emergency conditions. However, planned procedures should be performed under image guidance.

Echocardiographic Determinants of One-Year All-Cause Mortality in Patients With Chronic Heart Failure Complicated by Significant Functional Tricuspid Regurgitation.

BACKGROUND: Right ventricular (RV) dysfunction plays an important role in chronic heart failure (CHF). We evaluated the echocardiographic determinants of 1-year all-cause mortality in CHF patients with clinically relevant functional tricuspid regurgitation (TR). METHODS AND RESULTS: A total of 101 consecutive CHF patients (mean age 74 ± 10 years, 53% male) with moderate or severe functional TR were enrolled. Each patient underwent at least 2 echocardiography examinations in an interval of >6 months. Clinical follow-up was made after a median of 305 (interquartile range 164-365) days after the last echocardiography. The primary end point was all-cause mortality. Forty-two patients (42%) died during follow-up. Baseline right atrial (RA) area, TR volume increase and RV enlargement over time were significantly higher in nonsurvivors than survivors (all P < .05). Compared to baseline levels, systolic pulmonary artery pressure (sPAP) was significantly reduced in nonsurvivors during follow-up echocardiography (54 ± 19 vs 49 ± 21 mm Hg; P = .010), but significantly increased in survivors (48 ± 17 vs 54 ± 17 mm Hg; P = .001). Multivariable survival analysis suggested that baseline RA area ≥27 cm2 (hazard ratio [HR] 2.41, 95% confidence interval [CI] 1.21-4.80; P = .013), follow-up TR proximal isovelocity surface area regurgitant volume increase ≥15 mL (HR 2.27, 95% CI 1.20-4.31; P = .012), RV middle diameter increase ≥10 mm (HR 2.38, 95% CI 1.10-5.11; P = .027), and sPAP reduction ≥10 mm Hg (HR 3.04, 95% CI 1.51-6.13; P = .002) were determinants of 1-year all-cause mortality after the last echocardiography. Patients with 2 or 3 of these determinants were faced with significantly increased 1-year mortality (88% or 100%). CONCLUSIONS: Dynamic RV morphologic and functional changes during serial echocardiography are associated with significantly increased mortality risk in CHF patients with moderate or severe functional TR.

Influence of cardiac motion on stent lumen visualization in third generation dual-source CT employing a pulsatile heart model.

OBJECTIVE: To detect an in-stent restenosis, an invasive coronary angiography is commonly performed. Owing to the risk associated with this procedure, a non-invasive method to detect or exclude an in-stent restenosis is desirable. The purpose of this study was to evaluate the influence of cardiac motion on stent lumen visibility in a third-generation dual-source CT scanner (SOMATOM Force; Siemens Healthcare, Forchheim, Germany), employing a pulsatile heart model (CoroSim®; Mecora, Aachen, Germany). METHODS: 13 coronary stents with a diameter of 3.0 mm were implanted in plastic tubes filled with a contrast medium and then fixed onto the pulsatile phantom heart model. The scans were performed while the heart model mimicked the heartbeat. Coronary stents were scanned in an orientation parallel to the scanner z-axis. The evaluation of the stents was performed by employing a medium sharp convolution kernel optimized for vascular imaging. RESULTS: The mean visible stent lumen was reduced from 65.6 ± 5.7% for the stents at rest to 60.8 ± 4.4% for the stents in motion (p-value: <0.001). CONCLUSION: While the difference in lumen visibility between stents in motion and at rest was significant, the use of this third-generation dual-source CT scanner enabled a high stent lumen visibility under the influence of cardiac motion. Whether this translates into a clinical setting has to be evaluated in further patient studies. Advances in knowledge: The employed modern CT scanner enables a high stent lumen visibility even under the influence of cardiac motion, which is important to detect or exclude an in-stent restenosis.

Systematic Echocardiographic Evaluation of Mitral Valve Regurgitation for Transcatheter Edge-to-Edge Repair.

In patients with relevant mitral regurgitation (MR), transcatheter edge-to-edge repair (also called MitraClip) provides an alternative treatment option especially for inoperable or high-risk patients. In preparation for the procedure, echocardiography is the method of choice for assessment of mitral valve (MV) morphology and function and thus provides important information if successful treatment of MR can be accomplished by MitraClip. This review article provides structured and detailed guidance how to systematically assess functional and degenerative MR and MV pathology by echocardiography in order to select eligible patients for this procedure. Furthermore, it highlights state-of-the-art echocardiographic methods and potential pitfalls in patient selection.

In Vitro Comparison of Second- and Third-generation Dual-source CT for Coronary Stent Visualization at Different Tube Potentials.

RATIONALE AND OBJECTIVES: The study aimed to evaluate in vitro stent lumen visibility of coronary stents in a second- and third-generation dual-source computed tomography (CT) system at 100 and 120 kVp tube potential. MATERIALS AND METHODS: Twenty-six coronary stents ranging from 2.25 to 4.0 mm in diameter were implanted in a coronary vessel phantom. Scans were performed at 100 and 120 kVp tube potential. Evaluation was performed using a medium-sharp kernel in both systems (B46f in the second-generation and Bv49 in the third-generation model) and a sharp (Bv59) convolution kernel optimized for vascular imaging in the third-generation CT. RESULTS: The median visible stent lumen diameter in the second-generation system was higher at 120 kVp with a median of 62.0% compared to 56.3% at 100 kVp (P < 0.001). The median visible diameter in the third-generation system was significantly higher applying the Bv49 kernel with 66.7% at 120 kVp and 61.1% at 100 kVp (both P < 0.001). When applying the Bv59 kernel, visible stent lumen further increased to 69.3% at 120 kVp and 66.7% at 100 kVp. Additionally, stent lumen was assessed using full width at half maximum, resulting in a comparable increase in luminal diameter at corresponding tube potential. CONCLUSIONS: Third-generation dual-source CT provides superior stent lumen visibility at equivalent tube potential and at reduced tube potential of 100 kVp when compared to 120 kVp in a second-generation system, at least when manually assessed.

Prevalence of severe mitral regurgitation eligible for edge-to-edge mitral valve repair (MitraClip).

OBJECTIVES: We assessed the prevalence of moderately severe or severe mitral regurgitation (MR) justifying edge-to-edge mitral valve (MV) repair (MitraClip(®)) in patients attending the University Hospital Wuerzburg, a tertiary care centre located in Wuerzburg, Germany. BACKGROUND: Transcatheter edge-to-edge MV repair of advanced MR is a non-surgical treatment option in inoperable and high-risk patients. It is unknown how many patients are potentially eligible for MitraClip(®) since several anatomical prerequisites of the MV apparatus have to be met for optimal treatment results. METHODS: Using a novel clinical data warehouse we searched for all patients attached to our Department of Internal Medicine from 01/2008 to 01/2012 with moderately severe or severe MR and aged ≥18 years. The current status of their treatment regime and eligibility for MitraClip(®) was assessed and re-evaluated according to current guidelines and echocardiographic criteria. RESULTS: The search of electronic medical records amongst 43,690 patients employed an innovative validated text extraction method and identified 331 patients with moderately severe or severe MR who had undergone echocardiographic assessment at our institution. Of these, 125 (38 %) received MV surgery and 206 (62 %) medical therapy only. Most patients not undergoing surgery had secondary MR (70 %). After evaluation of medical and echocardiographic data of medically treated patients (n = 206), 81 (39 %) were potential candidates for MitraClip(®) therapy, and 90 (44 %) died during the median follow-up time of 23 months. CONCLUSION: A large fraction of patients with moderately severe or severe MR but not operated was detected. Medically treated patients had a bad prognosis and about 40 % of them were potential candidates for MitraClip(®) therapy.

Thrombus-in-Transit Following Watchman Device Implantation.

Thrombus-in-transit crossing an interatrial communication is a rare but potentially serious clinical condition, which has so far not been described after implantation of left atrial appendage (LAA) closure devices. Here, we describe the case of a 76-year-old woman with permanent atrial fibrillation and contraindication for oral anticoagulation therapy, who developed pericardial tamponade and acute pulmonary embolism with visible thrombus-in-transit formation following LAA closure. Most likely manipulation of the Watchman device in the LAA during two failed attempts in device positioning led to pericardial tamponade and venous puncture, manual compression after completion of the procedure and further immobilization resulted in deep vein thrombosis with consecutive pulmonary embolism and thrombus-in-transit formation. This case highlights the value of echocardiography after LAA closure.

Does Simulation-Based Training Improve Procedural Skills of Beginners in Interventional Cardiology?--A Stratified Randomized Study.

OBJECTIVE: To assess whether mentored simulation-based-training can improve the procedural skills of beginners in coronary interventional procedures. BACKGROUND: Simulation based-catheter training is a valuable tool to practice interventional procedures. Whether this type of training enhances the procedural skills of fellows learning percutaneous coronary interventions has never been studied. METHODS: Eighteen cardiology fellows were randomized either into the simulation-based training (n = 9) or the control group (n = 9). The simulation group received 7.5 hours of virtual reality (VR) simulation training, whereas the control group attended 4.5 hours of lectures. Each participant had to perform a simple (pre-evaluation) and a more complex (post-evaluation) catheter intervention on a pulsatile coronary flow model in a catheterization laboratory. All procedures were videotaped, analyzed, and rated by 3 expert interventionalists, who were blinded to the randomization. To assess the individual performance level, a "skills score" was determined, comprising 14 performance characteristics (5-level Likert scale, maximum score of 70 points). RESULTS: The "skills score" increased by 5.8 ± 6.1 points in the VR simulation group and decreased by 6.7 ± 8.4 in the control group (P = 0.003) from the simple stenosis at pre- to the more complex lesion at post-evaluation demonstrating the effectiveness of simulation-based training. CONCLUSION: This pilot study suggests that curriculum-based mentored VR simulation training improves the performance level of cardiology fellows in coronary interventions. Further investigation to evaluate the effect on clinical outcomes is warranted.

Two-dimensional transesophageal echocardiography for aortic annular sizing in patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Accurate preoperative assessment of the aortic annulus dimension is crucial for successful transcatheter aortic valve implantation (TAVI). In this study we examined the accuracy of a novel method using two-dimensional transesophageal echocardiography (2D-TEE) for measurement of the aortic annulus. METHODS: We evaluated the theoretical impact of the measurement of the annulus diameter and area using the circumcircle of a triangle method on the decision to perform the procedure and choice of the prosthesis size. RESULTS: Sixty-three consecutive patients were scheduled for TAVI. Mean age was 82 ± 4 years, and 25 patients (55.6 %) were female. Mean aortic annulus diameter was 20.3 ± 2.2 mm assessed by TEE on the mid-esophageal long-axis view and 23.9 ± 2.3 mm using CT (p < 0.001). There was a tendency for the TEE derived areas using the new method to be higher (p < 0.001). The TEE measurements were on average 42.33 mm(2) higher than the CT measurements without an evidence of a systematic over- or under-sizing (p = 1.00). Agreement between TEE and CT chosen valve sizes was good overall (kappa = 0.67 and weighted kappa = 0.71). For patients who turned out to have no AR, the two methods agreed in 84.6 % of patients. CONCLUSIONS: CT remanis the gold standard in sizing of the aortic valve annulus. Nevertheless, sizing of the aortic valve annulus using TEE derived area may be helpful. The impact of integration of this method in the algorithm of aortic annulus sizing on the outcome of patients undergoing TAVI should be examined in future studies.

Differences in natural history of low- and high-gradient aortic stenosis from nonsevere to severe stage of the disease.

BACKGROUND: The aim of the present study was to assess and compare the disease progression of aortic stenosis (AS) subtypes from nonsevere to severe disease on the basis of measures of gradient and flow. METHODS: Seventy-seven patients with AS (mean aortic valve area, 1.3 ± 0.3 cm(2) at baseline) underwent echocardiographic examination, including two-dimensional speckle-tracking strain measurements. Patients were retrospectively grouped according to mean transvalvular pressure gradient (40 mm Hg) into low-gradient (LG/AS) and high-gradient (HG/AS) groups. The LG/AS group was further subdivided into low-flow (LF/LG; i.e., stroke volume index < 35 mL/m(2)) and normal-flow (NF/LG) groups. For subanalysis, the LF/LG group was split into two groups: "paradoxical" (P-LF/LG; ejection fraction > 50%) and "classical" LF/LG (C-LF/LG; ejection fraction < 50%). Follow-up echocardiography was performed in patients with severe AS after 3.3 ± 1.7 years. Survival status was ascertained after 5.0 ± 2.0 years. RESULTS: Coronary artery disease was more frequent in LG/AS than HG/AS patients. Already at baseline, LF/LG patients showed reduced left ventricular global systolic strain and reduced systemic arterial compliance compared with HG/AS patients (HG/AS, 1.0 ± 0.4 mL · mm Hg-(1) · m(-2); NF/LG, 0.9 ± 0.2 mL · mm Hg-(1) · m(-2); LF/LG, 0.6 ± 0.2 mL · mm Hg(-1) · m(-2); P < .001). The initially elevated valvuloarterial impedance increased significantly more in LG/AS than in the other groups (HG/AS, 2.2 ± 0.9 mm Hg · mL-(1) · m(-2); NF/LG, 2.2 ± 0.5 mm Hg · mL-(1) · m(-2); LF/LG, 3.2 ± 0.8 mm Hg · mL(-1) · m-(2); P < .001), while aortic valve area decreased by 42% in HG/AS versus 34% in NF/LG and 32% in LF/LG (P < .001). At follow-up, global systolic strain was significantly reduced in C-LF/LG (7.7 ± 2.5 vs 13.5 ± 2.9 in P-LF/LG, P < .001). In P-LF/LG, mitral E/E' ratio increased significantly from 8.9 ± 4.0 to 26.4 ± 9.2 (P < .05). CONCLUSIONS: In patients with AS with high-gradient physiology, the valve constitutes the primary problem. By contrast, low-gradient AS is a systemic disease with valvular, vascular, and myocardial components, resulting in a slower progression of transvalvular gradient, but worse clinical outcome. In C-LF/LG, impaired systolic function leads to an LG flow pattern, whereas the pathophysiology in P-LF/LG is predominantly a diastolic dysfunction.

Feasibility of a new method using two-dimensional transesophageal echocardiography for aortic annular sizing in patients undergoing transcatheter aortic valve implantation; a case-control study.

BACKGROUND: Accurate preoperative assessment of the aortic annulus dimension is crucial for successful transcatheter aortic valve implantation (TAVI). In this study we validated a new method using two-dimensional transesophageal echocardiography (2D-TEE) for measurement of the aortic annulus prior to TAVI. METHODS: We analysed 124 patients who underwent successful TAVI using a self-expandable prosthesis, divided equally into two groups; in the study group we used the cross sectional short axis 2D-TEE for measurement of the aortic annulus and in the control group we used the long axis 2D-TEE. RESULTS: Both groups were comparable regarding the clinical parameters. On the other hand, patients in the study group had less left ventricular ejection fraction (38.9 % versus 45.6 %, p = 0.01). The aortic valve annulus was, although not statistically significant, smaller in the study group (21.58 versus 23.28 mm, p = 0.25). Post procedural quantification of the aortic regurgitation revealed that only one patient in both groups had severe aortic regurgitation (AR), in this patient the valve was implanted deep. The incidence of significant AR was higher in the control group (29.0 % versus 12.9 %, p = 0.027). CONCLUSIONS: Sizing of the aortic valve annulus using cross-sectional 2D-TEE offers a safe and plausible method for patients undergoing TAVI using the self-expandable prosthesis and is significantly superior to using long axis 2D-TEE.

Next generation coronary CT angiography: in vitro evaluation of 27 coronary stents.

OBJECTIVES: To evaluate in-stent lumen visibility of 27 modern and commonly used coronary stents (16 individual stent types, two stents at six different sizes each) utilising a third-generation dual-source CT system. METHODS: Stents were implanted in a plastic tube filled with contrast. Examinations were performed parallel to the system's z-axis for all stents (i.e. 0°) and in an orientation of 90° for stents with a diameter of 3.0 mm. Two stents were evaluated in different diameters (2.25 to 4.0 mm). Examinations were acquired with a collimation of 96 × 0.6 mm, tube voltage of 120 kVp with 340 mAs tube current. Evaluation was performed using a medium-soft (Bv40), a medium-sharp (Bv49) and a sharp (Bv59) convolution kernel optimised for vascular imaging. RESULTS: Mean visible stent lumen of stents with 3.0 mm diameter ranged from 53.3 % (IQR 48.9 - 56.7 %) to 73.9 % (66.7 - 76.7 %), depending on the kernel used at 0°, and was highest at an orientation of 90° with 80.0 % (75.6 - 82.8 %) using the Bv59 kernel, strength 4. Visible stent lumen declined with decreasing stent size. CONCLUSIONS: Use of third-generation dual-source CT enables stent lumen visibility of up to 80 % in metal stents and 100 % in bioresorbable stents. KEY POINTS: • Blooming artefacts impair in-stent lumen visibility of coronary stents in CT angiography. • CT enables stent lumen visibility of up to 80 % in metal stents. • Stent lumen visibility varies with stent orientation and size. • CT angiography may be a valid alternative for detecting in-stent restenosis.