Stent dislodgement during withdrawal attempt into the guiding-catheter: A step-by-step retrieval technique.

Catheter-induced stent dislodgement may occur when attempting to withdraw the stent into the guide-catheter particularly in cases of guiding-catheter co-axiality issues. We present the management of a catheter-induced stent dislodgement with simultaneous loss of wire position.

Circumflex distortion following mitral valve repair.

Mitral valve repair or replacement poses a potential risk of injury to the left circumflex coronary artery (LCx). Such injuries can arise from either direct LCx injury caused by encircling or transfixing stitches, or indirect occlusion resulting from the distortion of adjacent tissues. We provide and illustrate a representative image depicting LCx distortion. Additionally, we offer guidance to aid angiographers in comprehending the angiographic appearance and the underlying mechanism of occlusion.

Long-term all-cause death prediction by coronary, aortic, and valvular calcification in patients with acute ST-segment elevation myocardial infarction.

BACKGROUND: To determine the prognostic value of cumulative calcification score of coronary artery calcification (CAC), thoracic aortic calcification (TAC) and aortic valve calcification (AVC) in acute ST segment elevation myocardial infarction (STEMI) patients. METHODS: This was a retrospective, single-center cohort study. A total of 332 STEMI patients who received primary percutaneous coronary intervention (PPCI) were enrolled in this study between January 2010 to October 2018. We assessed the calcification in the left anterior descending branch (LAD), left circumflex branch (LCX), right coronary artery (RCA), thoracic aorta, and aortic valve. Calcification of each part was counted as 1 point, and the cumulative calcification score was calculated as the sum of all points. The primary endpoint was all-cause mortality. Multivariate Cox proportional hazards models were used to determine association of cumulative calcification score with end points. The performance of the score was evaluated by receiver operating characteristic (ROC) curve analysis and absolute net reclassification improvement (NRI), compared with the Global Registry of Acute Coronary Events (GRACE) risk score. RESULTS: The overall population's calcification score was 2.0 ± 1.6. During a mean follow-up time of 69.8 ± 29.3 months, the all-cause mortality rate was 12.1%. Kaplan-Meier curve showed that the score was significantly associated with mortality (log-rank p < 0.001). The multivariable Cox proportional hazard analyses showed that a calcification score of 4-5 was independently associated with all-cause death in STEMI patients [hazard ratio (HR) = 2.32, 95% confidence interval (CI): 1.01-5.31, p = 0.046]. The area under the ROC curve (AUC) of the calcification score was 0.67 (95% CI: 0.61-0.72), and the AUC of the GRACE score was 0.80 (95% CI: 0.75-0.84). There was no statistical difference in the predictive value between both scores for 3-year mortality in STEMI patients after PPCI (p = 0.06). Based on the NRI analysis, the calcification score showed better risk classification compared with the GRACE score (absolute NRI = 6.63%, P = 0.027). CONCLUSION: The cumulative calcification score is independently associated with the long-term prognosis of STEMI patients after PPCI.

Active design of diffuse acoustic fields in enclosures.

This paper presents a numerical framework for designing diffuse fields in rooms of any shape and size, driven at arbitrary frequencies. That is, we aim at overcoming the Schroeder frequency limit for generating diffuse fields in an enclosed space. We formulate the problem as a Tikhonov regularized inverse problem and propose a low-rank approximation of the spatial correlation that results in significant computational gains. Our approximation is applicable to arbitrary sets of target points and allows us to produce an optimal design at a computational cost that grows only linearly with the (potentially large) number of target points. We demonstrate the feasibility of our approach through numerical examples where we approximate diffuse fields at frequencies well below the Schroeder limit.

Solving the hypersingular boundary integral equation for the Burton and Miller formulation.

This paper presents an easy numerical implementation of the Burton and Miller (BM) formulation, where the hypersingular Helmholtz integral is regularized by identities from the associated Laplace equation and thus needing only the evaluation of weakly singular integrals. The Helmholtz equation and its normal derivative are combined directly with combinations at edge or corner collocation nodes not used when the surface is not smooth. The hypersingular operators arising in this process are regularized and then evaluated by an indirect procedure based on discretized versions of the Calderón identities linking the integral operators for associated Laplace problems. The method is valid for acoustic radiation and scattering problems involving arbitrarily shaped three-dimensional bodies. Unlike other approaches using direct evaluation of hypersingular integrals, collocation points still coincide with mesh nodes, as is usual when using conforming elements. Using higher-order shape functions (with the boundary element method model size kept fixed) reduces the overall numerical integration effort while increasing the solution accuracy. To reduce the condition number of the resulting BM formulation at low frequencies, a regularized version α = ik/(k(2 )+ λ) of the classical BM coupling factor α = i/k is proposed. Comparisons with the combined Helmholtz integral equation Formulation method of Schenck are made for four example configurations, two of them featuring non-smooth surfaces.

A Modified Error in Constitutive Equation Approach for Frequency-Domain Viscoelasticity Imaging Using Interior Data.

This paper presents a methodology for the inverse identification of linearly viscoelastic material parameters in the context of steady-state dynamics using interior data. The inverse problem of viscoelasticity imaging is solved by minimizing a modified error in constitutive equation (MECE) functional, subject to the conservation of linear momentum. The treatment is applicable to configurations where boundary conditions may be partially or completely underspecified. The MECE functional measures the discrepancy in the constitutive equations that connect kinematically admissible strains and dynamically admissible stresses, and also incorporates the measurement data in a quadratic penalty term. Regularization of the problem is achieved through a penalty parameter in combination with the discrepancy principle due to Morozov. Numerical results demonstrate the robust performance of the method in situations where the available measurement data is incomplete and corrupted by noise of varying levels.

Association Between Aortic Wall Thrombus and Thromboembolic Events After Transfemoral Transcatheter Aortic Valve Replacement.

BACKGROUND: Thromboembolic events, particularly strokes, remain a major complication of transcatheter aortic valve replacement (TAVR). Embolic protection devices have failed to show significant clinical benefit in large randomized clinical trials. Aortic wall thrombus (AWT) is often observed on multidetector computed tomography during TAVR work-up, but its prognostic significance is uncertain. OBJECTIVES: This study sought to evaluate the association between the presence of AWT and the incidence of thromboembolic outcomes in patients undergoing transfemoral (TF) TAVR for severe aortic stenosis. METHODS: This was a prospective cohort study of consecutive patients who underwent TF TAVR for severe aortic stenosis between January 2011 and April 2022. A dedicated scale (range: 0-10) was qualitatively used to assess AWT. The primary outcome was a composite of procedural thromboembolic events defined as ischemic stroke, blue toe syndrome, bowel ischemia, or other solid organ infarction. The secondary endpoints were ischemic strokes and procedural death. RESULTS: Of the 641 patients included, severe AWT (score ≥8) was identified in 73 (11.4%). The presence of severe AWT was strongly associated with an increase in the primary outcome (OR: 8.48; 95% CI: 3.36-21.40; P < 0.001). This relationship persisted following multivariable analysis, which adjusted for comorbidities and procedural characteristics. The presence of severe AWT was also found to be associated with an increased incidence of stroke and procedural death (OR: 5.66; 95% CI: 2.00-15.30; P = 0.002 and OR: 4.66; 95% CI: 1.80-11.30; P = 0.002, respectively). CONCLUSIONS: The presence of severe AWT on preprocedural multidetector computed tomography is strongly associated with thromboembolic complications including stroke and mortality after TF TAVR.

Large Scale Parameter Estimation Problems in Frequency-Domain Elastodynamics Using an Error in Constitutive Equation Functional.

This paper presents the formulation and implementation of an Error in Constitutive Equations (ECE) method suitable for large-scale inverse identification of linear elastic material properties in the context of steady-state elastodynamics. In ECE-based methods, the inverse problem is postulated as an optimization problem in which the cost functional measures the discrepancy in the constitutive equations that connect kinematically admissible strains and dynamically admissible stresses. Furthermore, in a more recent modality of this methodology introduced by Feissel and Allix (2007), referred to as the Modified ECE (MECE), the measured data is incorporated into the formulation as a quadratic penalty term. We show that a simple and efficient continuation scheme for the penalty term, suggested by the theory of quadratic penalty methods, can significantly accelerate the convergence of the MECE algorithm. Furthermore, a (block) successive over-relaxation (SOR) technique is introduced, enabling the use of existing parallel finite element codes with minimal modification to solve the coupled system of equations that arises from the optimality conditions in MECE methods. Our numerical results demonstrate that the proposed methodology can successfully reconstruct the spatial distribution of elastic material parameters from partial and noisy measurements in as few as ten iterations in a 2D example and fifty in a 3D example. We show (through numerical experiments) that the proposed continuation scheme can improve the rate of convergence of MECE methods by at least an order of magnitude versus the alternative of using a fixed penalty parameter. Furthermore, the proposed block SOR strategy coupled with existing parallel solvers produces a computationally efficient MECE method that can be used for large scale materials identification problems, as demonstrated on a 3D example involving about 400,000 unknown moduli. Finally, our numerical results suggest that the proposed MECE approach can be significantly faster than the conventional approach of L(2) minimization using quasi-Newton methods.

Warmer winters are associated with lower levels of the cryoprotectant glycerol, a slower decrease in vitellogenin expression and reduced virus infections in winter honeybees.

Within the context of climate change, winter temperatures at high latitudes are predicted to rise faster than summer temperatures. This phenomenon is expected to negatively affect the diapause performance and survival of insects, since they largely rely on low temperatures to lower their metabolism and preserve energy. However, some insects like honeybees, remain relatively active during the winter and elevate their metabolic rate to produce endothermic heat when temperatures drop. Warming winters are thus expected to improve overwintering performance of honeybees. In order to verify this hypothesis, for two consecutive years, we exposed honeybee colonies to either a mild or cold winter. We then monitored the influence of wintering conditions on several parameters of honeybee overwintering physiology, such as levels of the cryoprotectant glycerol, expression levels of immune and antioxidant genes, and genes encoding multifunctional proteins, including vitellogenin, which promotes bee longevity. Winter conditions had no effect on the expression of antioxidant genes, and genes related to immunity were not consistently affected. However, mild winters were consistently associated with a lower investment in glycerol synthesis and a higher expression of fat body genes, especially apidaecin and vitellogenin. Finally, while we found that viral loads generally decreased through the winter, this trend was more pronounced under mild winter conditions. In conclusion, and without considering how warming temperatures might affect other aspects of honeybee biology before overwintering, our data suggest that warming temperatures will likely benefit honeybee vitality by notably reducing their viral loads over the winter.

Safety of conservative management for non-stenotic culprit lesions in STEMI patients treated with a two-step reperfusion strategy: a SUPER-MIMI sub-study.

Background: In the observational SUPER-MIMI study, a minimalist immediate mechanical intervention (MIMI) technique-which involves restoring blood flow in the acute phase and postponing stenting-was shown to be safe and effective among patients with a high thrombotic burden after ST-segment elevation myocardial infarction (STEMI). We aim to assess whether a non-stenting strategy after a SUPER-MIMI strategy was safe at 4-year follow-up in patients enrolled in the SUPER-MIMI study who were not stented. Methods: This prospective cohort study assessed the long-term outcomes of a subgroup of patients included in the SUPER-MIMI study. Results: Among the 155 patients enrolled in the SUPER-MIMI study, 57 patients (36.8%) benefited from a conservative management (without stenting or balloon angioplasty) and were included in the current substudy. The mean duration of follow-up was 4.1±1.0 years. Four patients (7.0%) presented definite culprit lesion re-thrombosis, all of which occurred in the right coronary artery. The re-thrombosis rate appeared to be higher among patients with larger vessels: 2.9%, 8.3%, and 28.6% in arteries with diameters of 3-<4, 4-<5, and ≥5 mm, respectively. The overall rate of target lesion revascularization was 10.5%. There was one cardiac death and three rehospitalizations for heart failure. Overall, 82.5% of patients remained event free at a mean of 4.1±1.0 years. Conclusions: Conservative management of non-stenotic culprit lesions after a SUPER-MIMI strategy was associated with a high rate of re-thrombosis, particularly in patients with large coronary arteries.

Principal image decomposition for multi-detector backscatter electron topography reconstruction.

Scanning Electron Microscopes (SEMs) often generate images with a shaded appearance which gives a natural 3D impression. Ergo, quite a few methods to reconstruct the 3D surface topography from these using shape-from-shading methods are available in the literature. Here, a novel approach is discussed which uses BackScatter Electron (BSE) images from multiple detectors to reconstruct the topography. Classically, algorithms exist which resort to a quad-BSE detector setup. However, other detector configurations are often found in SEMs. A set of images of these non-conforming detectors still contains enough information to allow for reconstruction, but requires a more general algorithm to do so. This article discusses a method based on a modal decomposition of the principal image components. The resulting method is shown to be efficient and independent of the number of detectors or their orientation. In fact, the orientation is identified as part of the algorithm and thus requires very little calibration.

Successful Treatment of Spontaneous Coronary Artery Dissection With Subintimal Tracking and Re-Entry Technique.

Percutaneous coronary intervention (PCI) remains necessary in patients with spontaneous coronary dissection (SCAD) with ongoing ischemia. However, PCI in SCAD is associated with poor results. Fenestration with a cutting balloon has been described to release the extraluminal compression. The authors describe 2 cases managed successfully with another fenestration technique-the subintimal tracking and re-entry technique. (Level of Difficulty: Advanced.).

Development of a Risk Score Based on Aortic Calcification to Predict 1-Year Mortality After Transcatheter Aortic Valve Replacement.

OBJECTIVES: The aim of this study was to develop a new scoring system based on thoracic aortic calcification (TAC) to predict 1-year cardiovascular and all-cause mortality. BACKGROUND: A calcified aorta is often associated with poor prognosis after transcatheter aortic valve replacement (TAVR). A risk score encompassing aortic calcification may be valuable in identifying poor TAVR responders. METHODS: The C4CAPRI (4 Cities for Assessing CAlcification PRognostic Impact) multicenter study included a training cohort (1,425 patients treated using TAVR between 2010 and 2014) and a contemporary test cohort (311 patients treated in 2015). TAC was measured by computed tomography pre-TAVR. CAPRI risk scores were based on the linear predictors of Cox models including TAC in addition to comorbidities and demographic, atherosclerotic disease and cardiac function factors. CAPRI scores were constructed and tested in 2 independent cohorts. RESULTS: Cardiovascular and all-cause mortality at 1 year was 13.0% and 17.9%, respectively, in the training cohort and 8.2% and 11.8% in the test cohort. The inclusion of TAC in the model improved prediction: 1-cm3 increase in TAC was associated with a 6% increase in cardiovascular mortality and a 4% increase in all-cause mortality. The predicted and observed survival probabilities were highly correlated (slopes >0.9 for both cardiovascular and all-cause mortality). The model's predictive power was fair (AUC 68% [95% confidence interval [CI]: 64% to 72%]) for both cardiovascular and all-cause mortality. The model performed similarly in the training and test cohorts. CONCLUSIONS: The CAPRI score, which combines the TAC variable with classical prognostic factors, is predictive of 1-year cardiovascular and all-cause mortality. Its predictive performance was confirmed in an independent contemporary cohort. CAPRI scores are highly relevant to current practice and strengthen the evidence base for decision making in valvular interventions. Its routine use may help prevent futile procedures.

Postoperative treatment with angiotensin-converting enzyme inhibitors in patients with preoperative reduced left ventricular systolic function.

OBJECTIVE: The utility of angiotensin-converting enzyme inhibitors (ACE-Is) as early substitutes for dobutamine was studied after cardiac surgery in patients with preoperative left ventricular ejection fraction (LVEF)