Benefits of the selective invasive strategy guided by CTA and CTA-derived fractional flow reserve in patients with coronary artery disease.

BACKGROUND: Coronary computed tomography angiography (CTA) has high diagnostic accuracy in ruling out significant stenosis of coronary arteries. The additional use of CTA- derived fractional flow reserve (FFR) further enhances diagnostic utility of coronary CTA. Some patients interrogated non-invasively have diseased coronary arteries and undergo further diagnostic testing, including invasive coronary angiography (ICA). Patients with one-vessel disease may benefit from invasive interrogation limited to the diseased vessel only. AIMS: We analyzed the impact of a "diseased-vessel-only" selective invasive diagnostic approach in 100 patients undergoing ICA following coronary CTA (and CT-FFR) as compared to the traditional "full ICA" approach. We aimed to compare contrast volume and radiation dose used during ICA in both scenarios, seeking potential benefits for the patient in reducing those values by the "dis-eased-vessel-only" approach. RESULTS: Sensitivity, specificity, positive predictive value, and negative predictive value of CTA in prediction of subsequent revascularization were 96%, 75%, 51%, and 99%, respectively, and for CT-FFR 90%, 90%, 69%, and 97%, respectively. Using CTA as a method to guide ICA would reduce contrast volume and estimated radiation dose (ED) by 35% and 42.0%, respectively (P <0.0001 for both). Taking into consideration CT-FFR results, contrast volume would be reduced by 57% and ED by 69% (P <0.0001 for both). CONCLUSION: These real-world data support the concept that vessels with <50% diameter stenosis on quantitative computed tomography and with hemodynamically insignificant CTA-derived FFR result may be omitted during ICA. Such an approach would result in substantial reductions in con-trast media volume used, as well as patients' exposure to radiation during ICA, while not leading to misdiagnoses.

Incidence and Predictors of Clinically Significant Bleedings after Transcatheter Left Atrial Appendage Closure.

BACKGROUND: Transcatheter left atrial appendage closure (LAAC) is performed in patients unsuitable for long-term anticoagulation, predominantly due to prior bleeding events. The study aimed to investigate the incidence and predictors of clinically significant bleeding (CSB) post-LAAC. METHODS: Consecutive patients after LAAC with an Amplatzer or WATCHMAN device were analyzed (05.2014-11.2019). Bleeding was classified as CSB when associated with at least one of the following: death, ≥2 g/dL hemoglobin drop, ≥2 blood units transfusion, critical anatomic site, or hospitalization/invasive procedure. RESULTS: Among 195 patients (age 74 (68-80), 43.1% females, HAS-BLED score 2.0 (2.0-3.0)), during median follow-up of 370 (IQR, 358-392) days, there were 15 nonprocedural CSBs in 14 (7.2%) patients. Of those, 9 (60.0%) occurred during postprocedural dual antiplatelet therapy (DAPT) (median 46 (IQR: 16-60) days post-LAAC) vs. 6 (40%) after DAPT discontinuation (median 124 (81-210) days post-LAAC), translating into annualized CSB rates of 14.0% (per patient-year on DAPT) vs. 4.6% (per patient-year without DAPT). In 92.9% (13/14) of patients, the post-LAAC nonprocedural CSB was a recurrence from the same site as bleeding pre-LAAC. In the multivariable model, admission systolic blood pressure (SBP) > 127 mmHg (HR = 10.73, 1.37-84.26, p = 0.024), epistaxis history (HR = 5.84, 1.32-25.89, p = 0.020), permanent atrial fibrillation (AF) (HR = 4.55, 1.20-17.20, p = 0.025), and prior gastrointestinal bleeding (HR = 3.35, 1.01-11.08, p = 0.048) predicted post-LAAC CSB. CONCLUSIONS: Nonprocedural CSBs after LAAC, with a similar origin as the pre-LAAC bleedings, were observed predominantly during postprocedural DAPT and predicted by elevated admission SBP, prior epistaxis, permanent AF, and gastrointestinal bleeding history. Whether a more reserved post-LAAC antiplatelet regimen and stringent blood pressure control may improve LAAC outcomes remains to be studied.

Residual stroke risk after left atrial appendage closure in patients with prior oral anticoagulation failure.

BACKGROUND: Patients with atrial fibrillation (AF) and oral anticoagulation (OAC) failure may benefit from left atrial appendage closure (LAAC), however, the evidence is scarce. We report outcomes of LAAC in patients with OAC failure compared to those with classic indications of OAC contraindications. METHODS: Prospective registry of LAAC with Amplatzer or WATCHMAN device followed by dual antiplatelet therapy (DAPT) was analyzed (05.2014-11.2019). The study group included patients with OAC failure defined as stroke/TIA/PE/LAA thrombus (n = 39) during OAC, whereas the control group consisted of patients with OAC contraindications (n = 156). Structured follow-up at 3, 6, and 12 months was done. RESULTS: The study group compared to controls was younger [73 (IQR, 62-77) vs 74 (IQR, 68-81) years, P = 0.046], with higher CHA2DS2-VASc [5.0 (IQR, 3.0-6.0) vs 4.0 (IQR, 3.0-5.0), P = 0.001)], lower HAS-BLED [2.0 (IQR, 1.0-3.0) vs 3.0 (IQR, 2.0-3.0), P = 0.006] and similar proportion of WATCHMAN implantations (43.6% vs 44.2%, P = 1.000). The reduction from CHA2DS2-VASc predicted to observed annual stroke/TIA/PE rate was markedly smaller in the study vs control group (14% vs 77%) with 10.3% vs 1.9% stroke/TIA/PE respectively (P = 0.031). The reduction from HAS-BLED predicted to observed annual major nonprocedural bleeding rate was higher (100% vs 7.4%) with 0.0% vs 5.1% major bleedings respectively (P = 0.361). The device-related thrombosis remained similar (13.2% vs 11.3%, P = 0.778). CONCLUSIONS: Patients after LAAC for OAC failure and unremarkable prior bleeding history presented with high residual stroke and low bleeding risks. Therefore concomitant long-term OAC or prolonged DAPT should strongly be considered in this population.

Incremental value of volumetric quantification for myocardial perfusion imaging by computed tomography.

ackground: The extent of myocardial ischemia is the crucial prognostic factor for interventional treatment decision making for coronary artery disease. The ability of computed tomography per-fusion (CTP) to provide the missing volumetric information and its clinical value remains unknown. AIMS: The study aimed to compare a novel ischemic volume quantification method based on dynamic computed tomography perfusion (VOL CTP) with other CT-based imaging modalities for revascularization prediction. METHODS: In this prospective study, 53 (25 females, 63.5 [8.5] years old) consecutive symptomatic patients with 50%-90% coronary artery stenosis (n ≥1) on coronary computed tomography angiography underwent computed-tomography-derived fractional flow reserve (CT-FFR) analysis and dynamic CTP. We calculated the percentage of myocardial ischemia on the CTP-derived images. A 10% cut-off was used to define functionally significant ischemia. The outcomes include coronary revas-cularization during the follow-up of 2.5 (interquartile range, 1.4-2.8) years. Physicians were blinded to the results of CTP and CT-FFR. RESULTS: Of the 53 patients in the study (68 arteries with 50%-90% stenosis), 16 underwent revascularization (12 elective, 4 event-driven). In the CTP quantitative analysis, 26 patients had ischemia. Overall, 18 patients had ischemia ≥10% on volumetric ischemia quantification based on dynamic computed tomography perfusion (VOL CTP), and 28 patients had CT-FFR <0.8. VOL CTP, standard CTP, CT-FFR, and computed tomography coronary angiography (CTA) ≥70% performed well for the prediction of total revascularization. Area under the curve was 0.973 vs. 0.865, vs. 0.793, vs. 0.668, respectively. The VOL CTP with ≥10% cut-off was superior to the CT-FFR, standard CTP, and CTA ≥70% (P <0.001; P = 0.002 and P <0.001 respectively). CONCLUSIONS: VOL CTP quantification is feasible and adds important, actionable information to that provided by standard CTP or CT-FFR in patients with 50%-90% coronary artery stenosis.

Manufacturing Elements with Small Cross-Sections of 17-4 PH Steel (1.4542) with the Application of the DMLS Additive Manufacturing Method.

The application of direct metal laser sintering renders it possible to manufacture models with complex geometries. However, there are certain limits to the application of this method connected with manufacturing thin-walled cuboidal elements, as well as cylinders and holes with small diameters. The principal objective of the research was to determine the accuracy of manufacturing geometries with small cross-sections and the possibility of application in heat exchangers that are radiators with radially arranged ribs. To that end, four specimens were designed and manufactured; their geometries of representations assumed for the purpose of research (analysis) changed dimensions within the following scope: 10-0.1 mm. The specimens to be applied in the research were manufactured with 17-4 PH stainless steel (1.4542) with the application of 3D-DMLS printing and an EOS M270 printer. The measurement of accuracy was performed with the application of an optical stereomicroscope (KERN OZL-466). In addition to that, research into the chemical composition of the material, as well as the size of spherical agglomerates, was conducted with the application of a scanning electron microscope. The analysis of the chemical composition was conducted as well (after the sintering process). The analysis of the results based on the values received by means of measurements of the manufactured geometries was divided into three parts. Based on this, it is possible to conclude that the representation of models manufactured with the application of DMLS was comparable with the assumptions, and that the deviations between a nominal dimension and that received in the course of the research were within the following scope: 0-0.1 mm. At the final stage of research and based on the received results, two heat exchangers were manufactured.

Methodology for the Quality Control Process of Additive Manufacturing Products Made of Polymer Materials.

The objective of this publication is to present a quality control methodology for additive manufacturing products made of polymer materials, where the methodology varies depending on the intended use. The models presented in this paper are divided into those that are manufactured for the purpose of visual presentation and those that directly serve the needs of the manufacturing process. The authors also a propose a comprehensive control system for the additive manufacturing process to meet the needs of Industry 4.0. Depending on the intended use of the models, the quality control process is divided into three stages: data control, manufacturing control, and post-processing control. Research models were made from the following materials: RGD 720 photopolymer resin (PolyJet method), ABS M30 thermoplastic (FDM method), E-Partial photopolymer resin (DLP method), PLA thermoplastic (FFF method), and ABS thermoplastic (MEM method). The applied measuring tools had an accuracy of at least an order of magnitude higher than that of the manufacturing technologies used. The results show that the PolyJet method is the most accurate, and the MEM method is the least accurate. The findings also confirm that the selection of materials, 3D printing methods, and measurement methods should always account not only for the specificity and purpose of the model but also for economic aspects, as not all products require high accuracy and durability.

Visually Estimated RESOLVE Score Based on Coronary Computed Tomography to Predict Side Branch Occlusion in Percutaneous Bifurcation Intervention.

PURPOSE: The quantitative RESOLVE (Risk prEdiction of Side branch OccLusion in coronary bifurcation interVEntion) score derived from coronary computed tomography angiography (coronary CTA) was developed as a noninvasive and accurate prediction tool for side branch (SB) occlusion in coronary bifurcation intervention. We aimed to determine the ability of a visually estimated CTA-derived RESOLVE score (V-RESOLVE score) to predict SB occlusion in coronary bifurcation intervention. MATERIALS AND METHODS: The present study included 363 patients with 400 bifurcation lesions. CTA-derived V-RESOLVE score was derived and compared with the quantitative CTA-derived RESOLVE score. The scoring systems were divided into quartiles, and classified as the high-risk and non-high-risk groups. SB occlusion was defined as any decrease in thrombolysis in myocardial infarction flow grade after main vessel stenting. RESULTS: In total, 28 SB occlusions (7%) occurred. The concordance between visual and quantitative CTA analysis showed poor to excellent agreement (weighted κ range: 0.099 to 0.867). The area under the receiver operating curve for the prediction of SB occlusion was significantly higher for the CTA-derived V-RESOLVE score than for quantitative CTA-derived RESOLVE score (0.792 vs. 0.709, P=0.049). The total net reclassification index was 42.7% (P=0.006), and CTA-derived V-RESOLVE score showed similar capability to discriminate between high-risk group (18.6% vs. 13.8%, P=0.384) and non-high-risk group (3.8% vs. 4.9%, P=0.510) as compared with quantitative CTA-derived RESOLVE score. CONCLUSIONS: Visually estimated CTA-derived V-RESOLVE score is an accurate and easy-to-use prediction tool for the stratification of SB occlusion in coronary bifurcation intervention.