Multimodality imaging results of TAP versus novel modified TAP stenting in coronary bifurcation: From bench testing to first-in-man investigation.

OBJECTIVES: We investigated the results of T and small protrusion (TAP) versus a novel modification of TAP (mTAP) stenting by multimodality imaging in bench testing and in patients with coronary bifurcation lesions (CBL). BACKGROUND: TAP stenting is a suboptimal technique for bailout side branch (SB) stenting. METHODS: In a bench model, optical coherence tomography (OCT), microscopic examinations (ME), and computational fluid dynamics (CFD) were performed after TAP and mTAP stenting. In 20 patients with CBL, 80 intravascular ultrasound (IVUS) examinations were performed during mTAP stenting in which the SB stent was pulled-back to indent the inflated main vessel (MV) balloon and deployed while deflating it. For TAP stenting, the tip of the SB stent was positioned in the MV and deployed. RESULTS: In bench testing, OCT showed neocarina length (NL) was shorter and minimum stent area (MSA) was larger after mTAP versus TAP stenting (2.84 ± 0.70 vs. 4.80 ± 020 mm; 6.75 ± 1.50 vs. 4.5 ± 2.2 mm2 ; respectively; p < 0.05). By ME, NL was shorter and shear rate trended lower after mTAP versus TAP stenting. In patients, IVUS showed MSA was larger after versus before mTAP stenting (6.32 ± 0.58 vs. 5.21 ± 0.56 mm2 ; p < 0.01); NL was 1.43 ± 0.22 mm with SB ostium coverage. The Seattle Angina questionnaire (SAQ) score was higher at 6 months versus baseline (85 ± 4.0 vs. 48 ± 6.0, respectively; p < 0.001). CONCLUSIONS: This multimodality imaging study showed, for the first time, mTAP stenting resulted in larger stent area and shorter neocarina than TAP stenting in bench testing. In patients with CBL, mTAP stenting led to larger stent area, short neocarina with complete SB ostium coverage, and improved the SAQ score at follow-up.

Computerized technologies informing cardiac catheterization and guiding coronary intervention.

Advances in image processing and computer hardware have enabled the development of user-friendly software which operate in real-time and can be used in the catheterization laboratory to facilitate percutaneous coronary intervention (PCI). The two dimensional-(2D) quantitative coronary angiography (QCA) systems that have traditionally been used to assess lesion severity have been replaced by 3D-QCA systems, enabling more reliable evaluation of vessel geometry and lesion dimensions. This also allows 3D reconstruction of coronary bifurcation anatomy and generation of models that can be processed by computational fluid dynamic techniques to reliably detect flow-limiting lesions. More recently, software has been introduced that has the capability of generating a digital silhouette of the coronary arteries superimposed onto X-ray angiography to facilitate wire crossing and stent placement, and potentially reduce contrast use. In parallel, methodologies have been developed that operate with an accessible interface and can process intravascular imaging data, reliably quantify lesion severity and co-register intravascular and X-ray angiographic data to comprehensively assess plaque distribution and guide PCI. The above advances are used in daily practice to improve procedural results and outcomes. This review aims to provide an overview of the developments in the field - it presents the computer-based technologies that have been designed to accurately assess lesion severity, summarizes the advantages and limitations of the systems introduced to co-register imaging data and discusses the potential value of the existing and emerging software in the catheterization laboratory.

Drug-coated balloons: Technical and clinical progress.

The advancement of drug-coated balloons (DCB) presents an alternative nonstent method in the percutaneous treatment of atherosclerotic lesions. While the current generation of drug-eluting stents (DES) are the device of choice, especially in coronary artery disease (CAD), DCB has potential applications in the treatment of de novo lesions, in-stent restenosis (ISR), bifurcations, and in peripheral artery disease (PAD). In terms of coronary clinical experience, DCB is used most in ISR scenarios and more data are collected to support the use of DCB in de novo lesions compared to best-in-class DES. The use of DCB in bifurcation side branch treatment has demonstrated safety, and with good angiographic and clinical outcomes, but more data from randomized trials will be required to assess its clinical value. For PAD, the clinical outcomes of DCB with and without debulking devices in diseased femoropopliteal arteries and treatment of below-the-knee (BTK) vessels with DCB are discussed. Current data demonstrated conflicting long-term safety outcomes in the use of paclitaxel devices in the femoral and/or popliteal arteries, while the role of DCB in BTK disease remains uncertain due to a lack of randomized controlled trial data. In summary, this review provides an overall view of current DCB technologies and progress, followed by an update on DCB clinical data in the treatment of CAD and PAD.

Evaluation of an in vitro coronary stent thrombosis model for preclinical assessment.

Stent thrombosis remains an infrequent but significant complication following percutaneous coronary intervention. Preclinical models to rapidly screen and validate therapeutic compounds for efficacy are lacking. Herein, we describe a reproducible, high throughput and cost-effective method to evaluate candidate therapeutics and devices for either treatment or propensity to develop stent thrombosis in an in vitro bench-top model. Increasing degree of stent malapposition (0.00 mm, 0.10 mm, 0.25 mm and 0.50 mm) was associated with increasing thrombosis and luminal area occlusion (4.1 ± 0.5%, 6.3 ± 0.5%, 19.7 ± 4.5%, and 92.6 ± 7.4%, p < 0.0001, respectively). Differences in stent design in the form of bare-metal, drug-eluting, and bioresorbable vascular scaffolds demonstrated differences in stent thrombus burden (14.7 ± 3.8% vs. 20.5 ± 3.1% vs. 86.8 ± 5.3%, p < 0.01, respectively). Finally, thrombus burden was significantly reduced when healthy blood samples were incubated with Heparin, ASA/Ticagrelor (DAPT), and Heparin+DAPT compared to control (DMSO) at 4.1 ± 0.6%, 6.9 ± 1.7%, 4.5 ± 1.2%, and 12.1 ± 1.8%, respectively (p < 0.01). The reported model produces high throughput reproducible thrombosis results across a spectrum of antithrombotic agents, stent design, and degrees of apposition. Importantly, performance recapitulates clinical observations of antiplatelet/antithrombotic regimens as well as device and deployment characteristics. Accordingly, this model may serve as a screening tool for candidate therapies in preclinical evaluation.

Efficacy and Reproducibility of Attenuation-Compensated Optical Coherence Tomography for Assessing External Elastic Membrane Border and Plaque Composition in Native and Stented Segments　- An In Vivo and Histology-Based Study.

BACKGROUND: Attenuation-compensated (AC) technique was recently introduced to improve the plaque characterization of optical coherence tomography (OCT). Histological validation demonstrated promising results but the efficacy and reproducibility of this technique for assessing in-vivo tissue composition remains unclear.Methods and Results:OCT images portraying native (n=200) and stented (n=200) segments and 31 histological cross-sections were analyzed. AC-OCT appeared superior to conventional (C)-OCT in detecting the external elastic lamina (EEM) borders (76% vs. 65.5%); AC-OCT enabled larger EEM arc detection compared with C-OCT (174.2±58.7° vs. 137.5±57.9°; P<0.001). There was poor agreement between the 2 techniques for detection of lipid in native and lipid and calcific tissue in stented segments (κ range: 0.164-0.466) but the agreement of C-OCT and AC-OCT was high for calcific tissue in native segments (κ=0.825). Intra and interobserver agreement of the 2 analysts was moderate to excellent with C-OCT (κ range: 0.681-0.979) and AC-OCT (κ range: 0.733-0.892) for all tissue types in both native and stented segments. Ex-vivoanalysis demonstrated that C-OCT was superior to AC-OCT (κ=0.545 vs. κ=0.296) for the detection of the lipid component in native segments. CONCLUSIONS: The AC technique allows better delineation of the EEM but it remains inferior for lipid pool detection and neointima characterization. Combined AC- and C-OCT imaging may provide additional value for complete assessment of plaque and neointima characteristics.

Complex coronary bifurcation treatment by a novel stenting technique: Bench test, fluid dynamic study and clinical outcomes.

OBJECTIVES: We assess the mid-term outcomes of ultrathin biodegradable polymer double stenting using a very minimal crushing (Nano-Crush) technique in large complex coronary bifurcation. BACKGROUND: Complex bifurcations have been suggested to be better approached by a planned double stent technique. METHODS: Two hundred and five consecutive patients (107 males and 98 females) referred for large complex coronary bifurcation percutaneous coronary interventions were enrolled. The technique was also evaluated by both a bench test with a silicon tubes phantom resembling a coronary bifurcation and a computed fluid dynamic (CFD) analysis. RESULTS: Left main bifurcation accounted for 40.9% of cases (84 patients). Mean angles between main branch (MB) and side branch (SB) were 63.6 ± 21.3°. SB intravascular ultrasound-calculated MSA was 5.6 ± 1.5 mm2 . Clinical follow-up was available for 100% of patients and at a mean follow-up of 16.2 ± 6.7 months 8 deaths, all due to cardiovascular reason, (3.9%, 4 patients for stroke, two for heart failure, one after surgical aortic valve substitution, and one after acute massive pulmonary embolism) and no presumptive stent thrombosis or target vessel induced ischemia were observed. Angiographic follow-up was available in 108 patients (52.7%) and showed a very low significant restenosis (5 patients, 4.6%). Bench study and CFD evaluation suggested a complete coverage of the SB ostium with a very high strut-free area at the SB. CONCLUSIONS: The revascularization of complex large coronary bifurcation disease using the Nano-crush technique appeared promising thanks to the favorable fluid dynamic profile, complete coverage of the SD ostium, and very small metal amount at the carina.

A multicenter post-marketing evaluation of the Elixir DESolve® Novolimus-eluting bioresorbable coronary scaffold system: First results from the DESolve PMCF study.

OBJECTIVES: To date, experience with bioresorbable scaffolds (BRS) that elute agents other than everolimus is limited. Thus, a post-marketing clinical follow-up study was conducted to evaluate the continued safety and effectiveness of the DESolve® NOVOLIMUS™ Eluting BRS as treatment for patients with stable coronary artery disease. BACKGROUND: The DESolve BRS combines a poly-l-lactide-based backbone with a biodegradable polylactide-based polymer and Novolimus, a macrocyclic lactone mTOR inhibitor. METHODS: One hundred and two patients (mean age 62 years, 77.5% male) were enrolled at 10 European sites. Comparison of baseline and post-procedural angiographic assessment was performed, and a device-oriented composite endpoint (comprising cardiac death, target vessel myocardial infarction, and clinically driven target lesion revascularization) and rate of scaffold thrombosis at 12 months were examined. RESULTS: The device was successfully delivered and deployed in 98.2% (107/109) of the lesions, with two failures to cross the lesion. A total of 100 patients (109 lesions) were treated with a DESolve BRS. Post-procedural angiographic assessment indicated an in-scaffold acute gain of 1.54 ± 0.44 mm, with a reduction in % diameter stenosis from 61.00 ± 11.29 to 12.69 ± 0.44. At 12 months, the device-oriented composite endpoint had occurred in 3.0% (3/100) of patients, with 1.0% (1/100) experiencing scaffold thrombosis and myocardial infarction and 3.0% (3/100) undergoing target lesion revascularization. There were no cardiac deaths. CONCLUSIONS: Results through 12 months indicate that the DESolve BRS is a safe and effective treatment for coronary lesions, though larger, long-term prospective studies are needed.

Local Hemodynamic Forces After Stenting: Implications on Restenosis and Thrombosis.

Local hemodynamic forces are well-known to modulate atherosclerotic evolution, which remains one of the largest cause of death worldwide. Percutaneous coronary interventions with stent implantation restores blood flow to the downstream myocardium and is only limited by stent failure caused by restenosis, stent thrombosis, or neoatherosclerosis. Cumulative evidence has shown that local hemodynamic forces affect restenosis and the platelet activation process, modulating the pathophysiological mechanisms that lead to stent failure. This article first covers the pathophysiological mechanisms through which wall shear stress regulates arterial disease formation/neointima proliferation and the role of shear rate on stent thrombosis. Subsequently, the article reviews the current evidence on (1) the implications of stent design on the local hemodynamic forces, and (2) how stent/scaffold expansion can influence local flow, thereby affecting the risk of adverse events.

Biomechanical stress in coronary atherosclerosis: emerging insights from computational modelling.

Coronary plaque rupture is the most common cause of vessel thrombosis and acute coronary syndrome. The accurate early detection of plaques prone to rupture may allow prospective, preventative treatment; however, current diagnostic methods remain inadequate to detect these lesions. Established imaging features indicating vulnerability do not confer adequate specificity for symptomatic rupture. Similarly, even though experimental and computational studies have underscored the importance of endothelial shear stress in progressive atherosclerosis, the ability of shear stress to predict plaque progression remains incremental. This review examines recent advances in image-based computational modelling that have elucidated possible mechanisms of plaque progression and rupture, and potentially novel features of plaques most prone to symptomatic rupture. With further study and clinical validation, these markers and techniques may improve the specificity of future culprit plaque detection.

The Glider registry.

BACKGROUND: Provisional stenting of the side-branch (SB) is the universally accepted gold standard while there is still controversy on the usefulness of routine dilatation of the SB ostium. Recrossing the struts of a previously deployed stent with a wire and a balloon can prove challenging and is occasionally unsuccessful, mainly because the balloon tip hits a stent strut. This prospective multicenter international registry tested the crossing ability procedural results of a new-dedicated ultrashort balloon specifically designed for side branch dilatation (Glider, TriReme Medical, Pleasanton, CA, USA). METHODS: One hundred and twenty five patients (for a total of 131 bifurcation lesions) were enrolled in the registry between January 2009 and May 2012. The Glider was used as first choice in alternative to conventional balloon (group I, 72%) or as bail-out after unsuccessful previous attempt at crossing with small conventional low-profile balloons (group II, 28%). Postprocedural coronary artery dissections and in-hospital MACE (death, myocardial infarction and repeat revascularization) were assessed. Technical success was defined as the ability of the Glider to recross the struts of a previously deployed stent while procedural success was defined as less of residual 50% diameter stenosis at the origin of the SB with a final TIMI 3 and/or freedom from in-hospital MACE. RESULTS: Technical success was achieved, respectively, in 92% (group I), and 83% (group II). Clinical and angiographic procedural success was achieved in 98% of the lesions. In Group II, no other balloon of the same size could cross in cases where Glider could not. A total of 13 complications were observed, including nine ostial SB dissection four of which needed a second stent on the SB, one stent loss, two severe coronary spasms, and two by thrombus formation. CONCLUSION: The unique possibility offered by this short dedicated balloon to orientate its beveled tip provides an effective strategy for recrossing stent struts when conventional low profile balloons fail achieving greater SB ostial expansion thus reducing the incidence of strut malapposition during provisional treatment of bifurcational lesions. © 2016 Wiley Periodicals, Inc.

Coronary evaginations and peri-scaffold aneurysms following implantation of bioresorbable scaffolds: incidence, outcome, and optical coherence tomography analysis of possible mechanisms.

BACKGROUND: Peri-stent coronary evaginations may disturb flow and have been proposed as possible risk factor for late stent thrombosis. We describe incidence, predictors, and possible mechanisms of coronary evaginations 12 months after implantation of bioresorbable vascular scaffolds (BVS). METHODS AND RESULTS: One hundred and two BVS implanted in 90 patients (age 63 ± 13 years, 71 males, 14 diabetics) were analysed with angiography and optical coherence tomography (OCT) 12 months after implantation. Evaginations were identified as any hollow in the luminal vessel contour between well-apposed struts and were classified as major when extending ≥3 mm with a depth ≥10% of the BVS diameter. Fifty-five (54%) of the BVS (50(56%) of the patients) had at least one evagination (6.1 ± 6.2 evaginations per BVS), with a mean volume of 1.9 ± 1.9 mm(3). Major evaginations were only found in one patient, and in-BVS aneurysms in three patients (4BVS). The presence of evaginations was strongly associated with that of malapposition (P = 0.003) and strut fractures (P = 0.01). No association could be shown between the presence and volume of the evaginations and any clinical variable or the presence of uncovered struts (P > 0.5). Peri-strut low-intensity areas (PSLIA) were present in 29 (53%) of the BVS with evaginations and 12 (26%) of those without (P = 0.0049); their presence was independently associated with the presence, the number (P < 0.003) and volume of the evaginations (P = 0.004) and with that of strut fracture. CONCLUSIONS: Optical coherence tomography-detected evaginations are relatively common after BVS implantation, but, as for modern drug-eluting metallic stents, major evaginations are very rare. Optical coherence tomography evidence of immature neointima and strut fractures were associated with more severe development of evaginations.

Inducing Persistent Flow Disturbances Accelerates Atherogenesis and Promotes Thin Cap Fibroatheroma Development in D374Y-PCSK9 Hypercholesterolemic Minipigs.

BACKGROUND: Although disturbed flow is thought to play a central role in the development of advanced coronary atherosclerotic plaques, no causal relationship has been established. We evaluated whether inducing disturbed flow would cause the development of advanced coronary plaques, including thin cap fibroatheroma. METHODS AND RESULTS: D374Y-PCSK9 hypercholesterolemic minipigs (n=5) were instrumented with an intracoronary shear-modifying stent (SMS). Frequency-domain optical coherence tomography was obtained at baseline, immediately poststent, 19 weeks, and 34 weeks, and used to compute shear stress metrics of disturbed flow. At 34 weeks, plaque type was assessed within serially collected histological sections and coregistered to the distribution of each shear metric. The SMS caused a flow-limiting stenosis, and blood flow exiting the SMS caused regions of increased shear stress on the outer curvature and large regions of low and multidirectional shear stress on the inner curvature of the vessel. As a result, plaque burden was ≈3-fold higher downstream of the SMS than both upstream of the SMS and in the control artery (P<0.001). Advanced plaques were also primarily observed downstream of the SMS, in locations initially exposed to both low (P<0.002) and multidirectional (P<0.002) shear stress. Thin cap fibroatheroma regions demonstrated significantly lower shear stress that persisted over the duration of the study in comparison with other plaque types (P<0.005). CONCLUSIONS: These data support a causal role for lowered and multidirectional shear stress in the initiation of advanced coronary atherosclerotic plaques. Persistently lowered shear stress appears to be the principal flow disturbance needed for the formation of thin cap fibroatheroma.

Estimation of coronary wave intensity analysis using noninvasive techniques and its application to exercise physiology.

Wave intensity analysis (WIA) has found particular applicability in the coronary circulation where it can quantify traveling waves that accelerate and decelerate blood flow. The most important wave for the regulation of flow is the backward-traveling decompression wave (BDW). Coronary WIA has hitherto always been calculated from invasive measures of pressure and flow. However, recently it has become feasible to obtain estimates of these waveforms noninvasively. In this study we set out to assess the agreement between invasive and noninvasive coronary WIA at rest and measure the effect of exercise. Twenty-two patients (mean age 60) with unobstructed coronaries underwent invasive WIA in the left anterior descending artery (LAD). Immediately afterwards, noninvasive LAD flow and pressure were recorded and WIA calculated from pulsed-wave Doppler coronary flow velocity and central blood pressure waveforms measured using a cuff-based technique. Nine of these patients underwent noninvasive coronary WIA assessment during exercise. A pattern of six waves were observed in both modalities. The BDW was similar between invasive and noninvasive measures [peak: 14.9 ± 7.8 vs. -13.8 ± 7.1 × 10(4) W·m(-2)·s(-2), concordance correlation coefficient (CCC): 0.73, P < 0.01; cumulative: -64.4 ± 32.8 vs. -59.4 ± 34.2 × 10(2) W·m(-2)·s(-1), CCC: 0.66, P < 0.01], but smaller waves were underestimated noninvasively. Increased left ventricular mass correlated with a decreased noninvasive BDW fraction (r = -0.48, P = 0.02). Exercise increased the BDW: at maximum exercise peak BDW was -47.0 ± 29.5 × 10(4) W·m(-2)·s(-2) (P < 0.01 vs. rest) and cumulative BDW -19.2 ± 12.6 × 10(3) W·m(-2)·s(-1) (P < 0.01 vs. rest). The BDW can be measured noninvasively with acceptable reliably potentially simplifying assessments and increasing the applicability of coronary WIA.

Is high pressure postdilation safe in bioresorbable vascular scaffolds? Optical coherence tomography observations after noncompliant balloons inflated at more than 24 atmospheres.

OBJECTIVES: Optical coherence tomography (OCT) was used to investigate integrity and expansion of bioresorbable drug-eluting scaffolds (BVS) after high-pressure postdilation (HPPD). BACKGROUND: Because of concerns about the risk of BVS damage, postdilation was not recommended and applied in the existing randomized studies and most registries. Recent real world data suggest incomplete BVS expansion cause higher rates of thrombosis. In vivo confirmation of the safety of high pressure postdilation is of paramount importance. METHODS: Data from final OCT examination of consecutive implanted BVS, postdilated with noncompliant (NC) balloons at pressure ≥24 atm were analyzed. The following stent performance indices were assessed with OCT: mean and minimal lumen and scaffold area, residual area stenosis (RAS), incomplete strut apposition (ISA), tissue prolapse, eccentricity index (EI), symmetry index (SI), strut fractures, and edge dissections. RESULT: Twenty-two BVS postdilated at high pressure were analyzed. The average maximal postdilation balloon inflation (maxPD) was 28 ± 3 atm. High pressure OPN NC Balloon (SIS Medical AG, Winterthur Switzerland) was used in 41% of postdilations with a maximal PD of 30 ± 4.7 atm. Final mean and minimal lumen area were 6.8 ± 1.4 and 5.5 ± 1.4 mm(2) , respectively. OCT showed low percentage of RAS (16 ± 9.6%), and low percentage of ISA (1.8 ± 2.4%). Mean EI was 0.86 ± 0.02 and SI 0.35 ± 0.14. OCT analysis showed one edge dissection and no scaffold fractures. CONCLUSIONS: BVS deployment optimization using HPPD does not cause BVS disruption and is associated with a good BVS expansion, low rate of strut malapposition and edge dissections.

Stent fracture: Insights on mechanisms, treatments, and outcomes from the food and drug administration manufacturer and user facility device experience database.

OBJECTIVES: Stent fracture (SF) is an uncommon complication following percutaneous coronary intervention. Previous studies of SF have either been small single-center studies or have reported data mainly from first generation platforms. The FDA MAUDE database was used to identify cases of SF to gain mechanistic insight into procedural and anatomical factors predisposing to this complication, to define treatment and associated clinical outcomes in contemporary and first generation stent platforms. METHODS AND RESULTS: Using defined search terms, 376 unique reports of SF were identified in the FDA MAUDE database of which 336 (89.4%) occurred in first generation stent platforms with 96.1% occurring in the Cypher platform. The remaining 40 reports (10.6%) occurred with a similar distribution of cases across different contemporary platforms. Common vessel characteristics associated with SF included calcification, tortuosity, stent overlap, and significant angulation with the most common modality of presentation being in-stent restenosis or stent thrombosis. CONCLUSIONS: SF occurs most commonly in first generation Cypher stents with a similar distribution of cases across different contemporary platforms. Optimal treatment strategy remains unclear with the decision to treat and the modality of treatment utilized depending on the type and severity of SF.

Immediate results of bifurcational stenting assessed with optical coherence tomography.

BACKGROUND: A tubular stent may adapt with difficulty to coronary bifurcation lesions (CBLs). METHODS: Time domain or frequency domain (FD) optical coherence tomography (OCT) was performed to assess strut apposition immediately after stent implantation across four segments inside the bifurcation, in a consecutive series of patients. OCT pullbacks were performed in the main vessel (MV). RESULTS: A total of 13,142 struts in 45 CBL in 41 patients were assessed. Strut malapposition was significantly more frequent in the half bifurcation facing the side-branch (SB) ostium (42.9%) than in the proximal segment of the bifurcation 11.8%, half bifurcation opposite the SB 6.7%, or the distal segment 5.7% (all P < 0.0001). Lesions (n = 15) treated with stenting of both MV and SB had a total higher rate of malapposition than those (n = 30) treated with stenting of the MV only (17.6% vs. 9.5%; P = 0.0014). In latter group, lesions treated with FD-OCT-guided stent implantation (n = 13) presented a lower rate of malapposition than those treated with conventional angiographic-guided stent implantation (n = 17) (7.1% vs. 17.5%; P = 0.005). CONCLUSIONS: In CBL, strut malapposition is particularly high at the SB ostium. However, a strategy of stenting MV only with adjunctive FD-OCT guidance is associated with lower rates of malapposition.

Crush, culotte, T and protrusion: which 2-stent technique for treatment of true bifurcation lesions? - insights from in vitro experiments and micro-computed tomography.

BACKGROUND: Percutaneous coronary intervention of complex true bifurcation lesions often fails to ensure continuous stent coverage and strut apposition in both the side branch and main vessel. Struts left unopposed floating in the lumen disturb blood flow and are increasingly recognized as increasing the risk of stent thrombosis. METHODS AND RESULTS: In this study, we compared the results of different bifurcation treatment strategies: Crush (n=5); Culotte (n=3); T-/T with Protrusion (TAP) (n=4) using drug-eluting stents deployed in-vitro in representative coronary bifurcation models. After final kissing balloon post-dilatation, the rate of malapposition within the bifurcation quantified from micro-computed tomography scanning was on average 41.5 ± 8.2% with the Crush technique, reduced to respectively 31.4 ± 5.2% with Culotte and 36.7 ± 8.0% with T-/TAP approach. Overlaying layers of struts in the Crush and Culotte techniques lead to a significantly higher rate of strut malapposition in the proximal vessel than with the T-/TAP technique (Crush: 39.1 ± 10.7%, Culotte: 26.1 ± 7.7%, TAP: 4.2 ± 7.2%, P<0.01). Maximal wall-malapposed strut distance was also found on average to be higher with the Crush (1.36 ± 0.4mm) and Culotte techniques (1.32 ± 0.1mm) than with T-/TAP (1.08 ± 0.1mm, P=0.04). CONCLUSIONS: In this model, the Crush technique resulted in a higher risk of malapposition than either the Culotte or T-/TAP technique.

Stent malapposition generates stent thrombosis: Insights from a thrombosis model.

BACKGROUND: Currently, there exists differing conclusions on the role of acute stent malapposition and its role in stent thrombosis (ST). The European Association of Percutaneous Cardiovascular Interventions (EAPCI) consensus recommends that acute malapposition <0.4 mm with longitudinal extension <1 mm need not be corrected since there is no clear correlation of malapposition with adverse clinical outcomes. However, malapposition was identified as the main mechanism of ST in the Bern and PESTO registries, and one of the three leading mechanism in the PRESTIGE study. METHODS: In this study, a validated perfused benchtop thrombosis model was deployed to evaluate the role of both stent under-expansion (UE) and acute stent malapposition (MA) on thrombus formation in vitro in a controlled reproducible environment. RESULTS: The results showed that UE alone did not result in acute thrombus formation, but UE together with MA did. The data suggested that a MA distance of 0.25 mm led to significant thrombus formation; and a positive correlation exists between the longitudinal extension of the MA and the thrombus volume formed. CONCLUSION: Experiments in this in vitro model demonstrated that platelets and a thrombosis cascade were activated and developed around large segments of malapposed stent. This was significantly more thrombus formation than in the under-expanded stent region.

Polymer Coating Integrity, Thrombogenicity and Computational Fluid Dynamics Analysis of Provisional Stenting Technique in the Left Main Bifurcation Setting: Insights from an In-Vitro Model.

Currently, the provisional stenting technique is the gold standard in revascularization of lesions located in the left main (LM) bifurcation. The benefit of the routine kissing balloon technique (KBI) in bifurcation lesions is still debated, particularly following the single stent treatment. We compared the latest-generation drug-eluting stent (DES) with no side branch (SB) dilatation "keep it open" technique (KIO) vs. KBI technique vs. bifurcation dedicated drug-eluting stent (BD-DES) implantation. In vitro testing was performed under a static condition in bifurcation silicone vessel models. All the devices were implanted in accordance with the manufacturers' recommendations. As a result, computational fluid dynamics (CFD) analysis demonstrated a statistically higher area of high shear rate in the KIO group when compared to KBI. Likewise, the maximal shear rate was higher in number in the KIO group. Floating strut count based on the OCT imaging was significantly higher in KIO than in KBI and BD-DES. Furthermore, according to OTC analysis, the thrombus area was numerically higher in both KIO and KBI than in the BD-DES. Scanning electron microscopy (SEM) analysis shows the highest degree of strut coating damage in the KBI group. This model demonstrated significant differences in CFD analysis at SB ostia with and without KBI optimization in the LM setting. The adoption of KBI was related to a meaningful reduction of flow disturbances in conventional DES and achieved results similar to BD-DES.

Telemedicine: Benefits for Cardiovascular Patients in the COVID-19 Era.

The recent pandemic with SARS-CoV-2 raises questions worldwide regarding telemedicine for housebound patients, including those with cardiovascular conditions. The need for further investigation, monitoring and therapeutic management are advancing practical issues which had not been identified for consideration prior to the pandemic. Using the marketing assessment, we identified the needs of the patients and evaluated the future steps necessary in the short term to meet them. The research found progress made via telemedicine in monitoring and conducting minor decisions (like up-titrating the doses of different medication regimens) in patients with several cardiovascular diseases (heart failure, atrial fibrillation, high blood pressure), as there is a worldwide trend to develop new telemonitoring biosensors and devices based on implantable delivered transcatheter. The worldwide telemedicine trend encourages a switch from small and hesitating steps to a more consistent assessment of the patients, based on high technology and Interventional Cardiology. Cardiovascular telemedicine, although made a sustainable effort in managing patients' health, has many obstacles to overcome before meeting all their needs. Data security, confidentiality and reimbursement are the top priorities in developing remote Cardiology. The regulatory institutions need to play an integrative role in leading the way for defining the framework of future telemedicine activities. The SARS-CoV-2 outbreak with all its tragedy served to reinforce the message that telemedicine services can be life-saving for cardiovascular patients. Once the Covid-19 era will fade away, telemedicine is likely to remain a complementary service of standard care. There is still room to improve the remote identification and investigation of heart disease, provide an accurate diagnosis and therapeutic regimen, and update regulations and guidelines to the new realities of technological progress in the field.