Christian Schlundt

Detection of Coronary Artery Stenoses With Thin-Slice Multi-Detector Row Spiral Computed Tomography and Multiplanar Reconstruction

Background—We analyzed the accuracy of multi-detector row spiral computed tomography (MDCT) using a 16-slice CT scanner with improved spatial and temporal resolution, as well as routine premedication with &bgr;-blockers for detection of coronary stenoses. Methods and Results—Seventy-seven patients with suspected coronary disease were studied by MDCT (12×0.75-mm cross-sections, 420 ms rotation, 100 mL contrast agent IV at 5 mL/s). Patients with a heart rate above 60/min received 50 mg atenolol before the scan. In axial MDCT images and multiplanar reconstructions, all coronary arteries and side branches with a diameter of 1.5 mm or more were assessed for the presence of stenoses exceeding 50% diameter reduction. In comparison to invasive coronary angiography, MDCT correctly classified 35 of 41 patients (85%) as having at least 1 coronary stenosis and correctly detected 57 of 78 coronary lesions (73%). After excluding 38 of 308 coronary arteries (left main, left anterior descending, left circumflex, and right coronary artery in 77 patients) classified as unevaluable by MDCT (12%), 57 of 62 lesions were detected, and absence of stenosis was correctly identified in 194 of 208 arteries (sensitivity: 92%; specificity: 93%; accuracy: 93%; positive and negative predictive values: 79% and 97%). Conclusions—MDCT coronary angiography with improved spatial resolution and premedication with oral &bgr;-blockade permits detection of coronary artery stenoses with high accuracy and a low rate of unevaluable arteries.

Coronary Computed Tomographic Prediction Rule for Time-Efficient Guidewire Crossing Through Chronic Total Occlusion : Insights From the CT-RECTOR Multicenter Registry (Computed Tomography Registry of Chronic Total Occlusion Revascularization)

OBJECTIVES This study sought to establish a coronary computed tomography angiography prediction rule for grading chronic total occlusion (CTO) difficulty for percutaneous coronary intervention (PCI). BACKGROUND The uncertainty of procedural outcome remains the strongest barrier to PCI in CTO. METHODS Data from 4 centers involving 240 consecutive CTO lesions with pre-procedural coronary computed tomography angiography were analyzed. Successful guidewire (GW) crossing ≤30 min was set as an endpoint to eliminate operator bias. The CT-RECTOR (Computed Tomography Registry of Chronic Total Occlusion Revascularization) score was developed by assigning 1 point for each independent predictor, and then summing all points accrued. Continuous distribution of scores was used to stratify CTO into 4 difficulty groups: easy (score 0); intermediate (score 1); difficult (score 2); and very difficult (score ≥3). Discriminatory performance was tested by 10-fold cross-validation and compared with the angiographic J-CTO (Multicenter CTO Registry of Japan) score. RESULTS Study endpoint was achieved in 55% of cases. Multivariable analysis yielded multiple occlusions, blunt stump, severe calcification, bending, duration of CTO ≥12 months, and previously failed PCI as independent predictors for GW crossing. The probability of successful GW crossing ≤30 min for each group (from easy to very difficult) was 95%, 88%, 57%, and 22%, respectively. Areas under receiver-operator characteristic curves for the CT-RECTOR and J-CTO scores were 0.83 and 0.71, respectively (p < 0.001). Both the original model fit and 10-fold cross-validation correctly classified 77.3% of lesions. CONCLUSIONS The CT-RECTOR score represents a simple and accurate noninvasive tool for predicting time-efficient GW crossing that may aid in grading CTO difficulty before PCI. (Computed Tomography Angiography Prediction Score for Percutaneous Revascularization for Chronic Total Occlusions [CT-RECTOR]; NCT02022878).

Comparison of contrast-enhanced breath-hold and free-breathing respiratory-gated imaging in three-dimensional magnetic resonance coronary angiography

Suppression of respiratory motion is one of the major challenges of magnetic resonance (MR) coronary angiography. Two approaches to compensate for respiratory motion have often been proposed: breath-hold (BH) and free-breathing respiratory-gated (FBRG) imaging. So far, however, these approaches have never been directly compared. MR coronary angiography was performed in 32 patients with suspected coronary artery disease. MR data were acquired using contrast-enhanced BH and FBRG 3-dimensional MR coronary angiographic techniques. MR images were compared with regard to image quality using quantitative parameters and with regard to accuracy for stenosis detection in the proximal and mid-coronary segments in comparison to x-ray angiography. With regard to image quality, BH was superior to FBRG. Signal-to-noise ratio was 29.1 +/- 10.7 for BH versus 18.8 +/- 9.7 for FBRG (p <0.05) and contrast-to-noise was 18.0 +/- 7.4 for BH versus 11.3 +/- 7.9 for FBRG (p </=0.05). One hundered seventy-one of 224 coronary artery segments (76%) were evaluable in BH compared with 155 of 224 in FBRG (69%). In the evaluable segments, BH demonstrated a sensitivity of 87% (26 of 30 stenoses detected) and specificity of 92% (129 of 141 nonstenotic segments correctly identified), whereas FBRG showed a sensitivity of 60% (15 of 25) and specificity of 89% (115 of 130). Overall accuracy was 91% (155 of 171) for BH and 84% (130 of 155) for FBRG. Sensitivity was significantly higher for BH (p = 0.0320), whereas specificity and overall accuracy were not significantly different. Thus, contrast-enhanced BH MR coronary angiography compares favorably to FBRG imaging with regard to image quality and detection of coronary stenoses.

Comparison of Intracoronary Versus Intravenous Administration of Adenosine for Measurement of Coronary Fractional Flow Reserve

Background—Measurement of fractional flow reserve (FFR) constitutes the current gold standard to evaluate the hemodynamic significance of coronary stenoses. Limited data validate the intracoronary application of adenosine against standard intravenous infusion. We systematically compared FFR measurements during intracoronary and intravenous application of adenosine about agreement and reproducibility. Methods and Results—We included 114 patients with an intermediate degree of stenosis in coronary angiography. Two FFR measurements were performed during intracoronary bolus injection (40 &mgr;g for the right and 80 &mgr;g for the left coronary artery, FFRic), and 2 FFR measurements during continuous intravenous infusion of adenosine (140 &mgr;g/kg per minute, FFRiv). FFR value, the time to reach FFR and patient discomfort (on a subjective scale from 0 for no symptoms to 5 for maximal discomfort) were recorded for each measurement. Mean time to FFR was 100±27 s for continuous intravenous infusion versus 23±14 s for intracoronary bolus administration of adenosine (P<0.001). Reported discomfort after intracoronary application was significantly lower compared with intravenous adenosine (subjective scale >0 in 35.1% versus 87.7% of the patients; P<0.001). Correlation between FFRiv and FFRic was extremely close (r=0.99; P<0.001) with no systematic bias in Bland–Altman analysis (bias 0.002 [confidence interval, −0.001 to 0.005]) and low intermethod variability (1.56%). Intramethod variability was not different between intravenous and intracoronary administration (1.47% versus 1.33%; P=0.5). Conclusions—Intracoronary bolus injection of adenosine (40 &mgr;g for the right and 80 &mgr;g for the left coronary artery) yields identical FFR results compared with intravenous infusion (140 &mgr;g/kg per minute), while requiring less time and offering superior patient comfort.

Diagnostic value of maximum intensity projections versus source images for assessment of contrast-enhanced three-dimensional breath-hold magnetic resonance coronary angiography.

Regenfus M, Ropers D, Achenbach S, et al. Diagnostic value of maximum intensity projections versus source images for assessment of contrast-enhanced three-dimensional breath-hold magnetic resonance coronary angiography. Invest Radiol 2003;38:200–206. Rationale and Objectives.We compared maximum intensity projections (MIP) versus original source images (SI) in respect to detection of coronary artery stenoses by means of magnetic resonance (MR) coronary angiography. Methods.MR coronary angiography was performed on 61 patients. MIP and SI were independently evaluated as to presence of significant stenoses in the proximal and midcoronary segments and compared with x-ray angiography. Results.A total of 315 of 427 (74%) coronary artery segments could be evaluated in MIP and 328 of 427 (77%) in SI. In segments able to be evaluated, MIP images demonstrated 84% (54/64) sensitivity and 87% (219/251) specificity, whereas SI images showed 85% (58/68) sensitivity and 90% (235/260) specificity. Overall accuracy was 87% (273/310) for MIP and 89% (293/328) for SI. There was no statistically significant difference between both modalities. Conclusions.The MIP reconstructions showed comparable accuracy to unprocessed SI. However, MIP postprocessing is compromised by a higher number of images that were unable to be evaluated due to overlap of coronary arteries with adjacent cardiac structures.

Three-dimensional on-line reconstruction of coronary bifurcated lesions to optimize side-branch stenting.

Treatment of coronary bifurcation lesions is technically challenging. Following advances in stent design, various methods of stent placement in bifurcation lesions (‘‘T,’’ ‘‘Y,’’ ‘‘V,’’ and ‘‘Culotte’’) have been described in the literature, with individual centers reporting satisfactory technical results. However, restenosis rates as high as 60% continue to be reported [1]. Recently, antiproliferative coating of coronary stents has proven to significantly reduce the amount of restenosis found in bifurcation lesions [2]. Of note, in this study, the majority of restenosis occurred at the ostium of the side branch following T-stenting. It was therefore hypothesized that these restenoses might result from inadequate or incomplete coverage of the ostium of the side branch, thereby reducing the efficacy of the drugeluting stent. To date, the most effective strategy to percutaneous therapy of bifurcation lesions needs to be carefully evaluated in randomized studies. Such randomized studies must take into account baseline anatomical differences (e.g., vessel size and bifurcation angle) of bifurcation lesions to individually determine the best strategy for a given bifurcation lesion. Therefore, tools to optimize treatment strategy and stent placement are highly desirable. The present report describes a new software that allows three-dimensional (3D) reconstruction of coronary bifurcation lesions and the individually related quantitative data.

Comparison of Fractional Flow Reserve Based on Computational Fluid Dynamics Modeling Using Coronary Angiographic Vessel Morphology Versus Invasively Measured Fractional Flow Reserve

Invasive fractional flow reserve (FFRinvasive), although gold standard to identify hemodynamically relevant coronary stenoses, is time consuming and potentially associated with complications. We developed and evaluated a new approach to determine lesion-specific FFR on the basis of coronary anatomy as visualized by invasive coronary angiography (FFRangio): 100 coronary lesions (50% to 90% diameter stenosis) in 73 patients (48 men, 25 women; mean age 67 ± 9 years) were studied. On the basis of coronary angiograms acquired at rest from 2 views at angulations at least 30° apart, a PC-based computational fluid dynamics modeling software used personalized boundary conditions determined from 3-dimensional reconstructed angiography, heart rate, and blood pressure to derive FFRangio. The results were compared with FFRinvasive. Interobserver variability was determined in a subset of 25 narrowings. Twenty-nine of 100 coronary lesions were hemodynamically significant (FFRinvasive ≤ 0.80). FFRangio identified these with an accuracy of 90%, sensitivity of 79%, specificity of 94%, positive predictive value of 85%, and negative predictive value of 92%. The area under the receiver operating characteristic curve was 0.93. Correlation between FFRinvasive (mean: 0.84 ± 0.11) and FFRangio (mean: 0.85 ± 0.12) was r = 0.85. Interobserver variability of FFRangio was low, with a correlation of r = 0.88. In conclusion, estimation of coronary FFR with PC-based computational fluid dynamics modeling on the basis of lesion morphology as determined by invasive angiography is possible with high diagnostic accuracy compared to invasive measurements.

Fatal Bioprosthetic Aortic Valve Endocarditis Due to Cardiobacterium valvarum

ABSTRACT Cardiobacterium valvarum was isolated from the blood of a 71-year-old man with fatal aortic valve endocarditis. The API NH system was used for phenotypic characterization of the C. valvarum strain. This is the first case of infective endocarditis caused by C. valvarum in Germany and the first case worldwide affecting a prosthetic valve and lacking an obvious dental focus.

3D printing for sizing left atrial appendage closure device: head-to-head comparison with computed tomography and transoesophageal echocardiography

AIMS Device sizing for LAA closure using transoesophageal echocardiography (TEE) can be challenging due to complex LAA anatomy. We investigated whether the use of 3D-printed left atrial appendage (LAA) models based on preprocedural computed tomography (CT) permits accurate device sizing. METHODS AND RESULTS Twenty-two (22) patients (73±8 years, 55% male) with atrial fibrillation requiring anticoagulation at high bleeding risk underwent LAA closure (WATCHMAN device). Preprocedurally, LAA was sized by TEE and third-generation dual-source CT. Based on CT, 3D printing models of LAA anatomy were created for simulation of device implantation. Device compression was assessed in a CT scan of the 3D model with the implanted device. Implantation was successful in all patients. Mean LAA ostium diameter based on TEE was 22±4 mm and based on CT 25±3 mm (p=0.014). Predicted device size based on simulated implantation in the 3D model was equal to the device finally implanted in 21/22 patients (95%). TEE would have undersized the device in 10/22 patients (45%). Device compression determined in the 3D-CT model corresponded closely with compression upon implantation (16±3% vs. 18±5%, r=0.622, p=0.003). CONCLUSIONS Patient-specific CT-based 3D printing models may assist device selection and prediction of device compression in the context of interventional LAA closure.

Bioresorbable vascular scaffold thrombosis in a consecutive cohort of 550 patients.

To determine the rate of bioresorbable vascular scaffold (BVS) thrombosis in a large, real‐world population.