Experimental and Numerical Study of a Synthetic Jet Ejector

A traditional synthetic jet ejector is a combination of synthetic jet and mixing tube or shroud in which flow from the surroundings is entrained through the space between the jet and shroud and discharged from the end of a mixing tube. An objective of the current research is to evaluate the accuracy of a previous simplified numerical model using results from an improved numerical model and an experimental synthetic jet ejector water flow facility. The improved model gives a better representation of the primary jet velocity profile by accurately modeling the piston motion using the dynamic mesh option. Also, flow approaching the secondary inlet plane is considered in the new model by including the surrounding fluid in the solution domain. The model is used to show the shortcomings of certain assumptions made in the simplified model. Experimentally, the phase-averaged velocity field within the shroud is determined using Particle Image Velocimetry. It is shown that the improved numerical model gives a more accurate prediction of the variation of phase-averaged volume flow rate throughout the cycle and the cycle averaged values than the previous simplified model. Also, the numerical and phase-averaged experimental flow field patterns show some similarities however, certain details of the profiles are quite different. Extremely high turbulence level or intense mixing is detected near the exit of the synthetic jet. This is thought to be responsible for the shorter flow development noticed in the experiments compared with the numerical solution

Use of Intravascular Imaging During Chronic Total Occlusion Percutaneous Coronary Intervention: Insights From a Contemporary Multicenter Registry

Background: Intravascular imaging can facilitate chronic total occlusion (CTO) percutaneous coronary intervention. Methods and Results: We examined the frequency of use and outcomes of intravascular imaging among 619 CTO percutaneous coronary interventions performed between 2012 and 2015 at 7 US centers. Mean age was 65.4±10 years and 85% of the patients were men. Intravascular imaging was used in 38%: intravascular ultrasound in 36%, optical coherence tomography in 3%, and both in 1.45%. Intravascular imaging was used for stent sizing (26.3%), stent optimization (38.0%), and CTO crossing (35.7%, antegrade in 27.9%, and retrograde in 7.8%). Intravascular imaging to facilitate crossing was used more frequently in lesions with proximal cap ambiguity (49% versus 26%, P<0.0001) and with retrograde as compared with antegrade‐only cases (67% versus 31%, P<0.0001). Despite higher complexity (Japanese CTO score: 2.86±1.19 versus 2.43±1.19, P=0.001), cases in which imaging was used for crossing had similar technical and procedural success (92.8% versus 89.6%, P=0.302 and 90.1% versus 88.3%, P=0.588, respectively) and similar incidence of major cardiac adverse events (2.7% versus 3.2%, P=0.772). Use of intravascular imaging was associated with longer procedure (192 minutes [interquartile range 130, 255] versus 131 minutes [90, 192], P<0.0001) and fluoroscopy (71 minutes [44, 93] versus 39 minutes [25, 69], P<0.0001) time. Conclusions: Intravascular imaging is frequently performed during CTO percutaneous coronary intervention both for crossing and for stent selection/optimization. Despite its use in more complex lesion subsets, intravascular imaging was associated with similar rates of technical and procedural success for CTO percutaneous coronary intervention. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02061436

Impact of Calcium on Chronic Total Occlusion Percutaneous Coronary Interventions

We sought to examine the impact of calcific deposits on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The outcomes of 1,476 consecutive CTO PCIs performed in 1,453 patients (65.5 +/- 10 years, 85% male) between 2012 and 2016 at 11 US centers were evaluated. Moderate or severe quantity of calcium was present in 58% of target lesions. Calcified lesions were more tortuous and more likely to have proximal cap ambiguity and interventional collaterals. PCI of moderately/severely calcified CTOs more often required use of the retrograde approach (54% vs 30%, p <0.001) and was associated with longer procedure and fluoroscopy time and higher air kerma radiation dose and contrast volume. Moderate/severe quantity of calcium was associated with lower technical (86.6% vs 93.8%, p <0.001) and procedural (84.4% vs 92.7%, p <0.001) success rates and higher incidence of major adverse cardiac events (3.7% vs 1.8%, p = 0.033). On multivariate analysis, the presence of moderate/severe quantity of calcium was not independently associated with technical success. Balloon angioplasty was the most common lesion preparation technique for calcified lesions, followed by rotational atherectomy and laser. To conclude, in a contemporary, multicenter registry, moderate/severe calcific deposits were present in 58% of attempted CTO lesions and were associated with higher use of the retrograde approach, lower success, and higher complication rates. However, on multivariable analysis, the amount of calcium was not independently associated with technical success. (C) 2017 Elsevier Inc. All rights reserved

Prevalence, indications and management of balloon uncrossable chronic total occlusions: Insights from a contemporary multicenter US registry

BACKGROUND: Balloon uncrossable lesions can be challenging to treat, requiring specialized techniques and equipment. METHODS: We examined the prevalence, clinical and angiographic characteristics, management and procedural outcomes of balloon uncrossable lesions in a multicenter chronic total occlusion (CTO) percutaneous coronary intervention (PCI) registry. RESULTS: Between 2012 and 2016, 718 CTO PCIs (in which the occlusion was successfully crossed with a guidewire) were performed in 701 patients at 11 US centers. Mean age was 65.6 ± 10 years and 84% of the patients were men. Balloon uncrossable lesions represented 9% of all CTOs. Balloon uncrossable CTOs had more moderate/severe calcification (82% vs. 52%, P \u3c 0.0001), moderate/severe tortuosity (61% vs. 35% P \u3c 0.0001) and higher J-CTO score (2.95 ± 1.32 vs. 2.43 ± 1.23, P = 0.005) as compared with the remaining lesions. Technical and procedural success was significantly lower for balloon uncrossable lesions (90.5% vs. 98.3%, P \u3c 0.0001 and 88.9% vs. 96.6% P = 0.004), respectively, but the incidence of major adverse events was similar (1.6% vs. 2.2%, P = 0.751). Balloon uncrossable lesions required longer procedure (208 [interquartile range: 135, 258] vs. 135 [94, 194] min, P \u3c 0.0001) and fluoroscopy (77 [52, 100] vs. 45 min [27, 75], P \u3c 0.0001) time. Techniques used to treat balloon uncrossable lesions included balloon-assisted microdissection (23%), excimer laser atherectomy (18%), and rotational atherectomy (16%). Excimer laser atherectomy and balloon-assisted microdissection were associated with the highest technical and procedural success rates. CONCLUSIONS: Balloon uncrossable CTOs are common, are associated with high rates of technical failure, and require specialized techniques for successful treatment. © 2016 Wiley Periodicals, Inc

Prevalence, indications and management of balloon uncrossable chronic total occlusions: Insights from a contemporary multicenter US registry

BackgroundBalloon uncrossable lesions can be challenging to treat, requiring specialized techniques and equipment. MethodsWe examined the prevalence, clinical and angiographic characteristics, management and procedural outcomes of balloon uncrossable lesions in a multicenter chronic total occlusion (CTO) percutaneous coronary intervention (PCI) registry. ResultsBetween 2012 and 2016, 718 CTO PCIs (in which the occlusion was successfully crossed with a guidewire) were performed in 701 patients at 11 US centers. Mean age was 65.610 years and 84% of the patients were men. Balloon uncrossable lesions represented 9% of all CTOs. Balloon uncrossable CTOs had more moderate/severe calcification (82% vs. 52%, P<0.0001), moderate/severe tortuosity (61% vs. 35% P<0.0001) and higher J-CTO score (2.95 +/- 1.32 vs. 2.43 +/- 1.23, P=0.005) as compared with the remaining lesions. Technical and procedural success was significantly lower for balloon uncrossable lesions (90.5% vs. 98.3%, P<0.0001 and 88.9% vs. 96.6% P=0.004), respectively, but the incidence of major adverse events was similar (1.6% vs. 2.2%, P=0.751). Balloon uncrossable lesions required longer procedure (208 [interquartile range: 135, 258] vs. 135 [94, 194] min, P<0.0001) and fluoroscopy (77 [52, 100] vs. 45 min [27, 75], P<0.0001) time. Techniques used to treat balloon uncrossable lesions included balloon-assisted microdissection (23%), excimer laser atherectomy (18%), and rotational atherectomy (16%). Excimer laser atherectomy and balloon-assisted microdissection were associated with the highest technical and procedural success rates. ConclusionsBalloon uncrossable CTOs are common, are associated with high rates of technical failure, and require specialized techniques for successful treatment. (c) 2016 Wiley Periodicals, Inc

Impact of Calcium on Chronic Total Occlusion Percutaneous Coronary Interventions

We sought to examine the impact of calcific deposits on the outcomes of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The outcomes of 1,476 consecutive CTO PCIs performed in 1,453 patients (65.5 ± 10 years, 85% male) between 2012 and 2016 at 11 US centers were evaluated. Moderate or severe quantity of calcium was present in 58% of target lesions. Calcified lesions were more tortuous and more likely to have proximal cap ambiguity and interventional collaterals. PCI of moderately/severely calcified CTOs more often required use of the retrograde approach (54% vs 30%,

Use of antegrade dissection re-entry in coronary chronic total occlusion percutaneous coronary intervention in a contemporary multicenter registry

BACKGROUND: We assessed efficacy and safety of chronic total occlusion (CTO) percutaneous coronary intervention (PCI) using antegrade dissection re-entry (ADR). METHODS: We examined outcomes of ADR among 1313 CTO PCIs performed at 11 US centers between 2012-2015. RESULTS: 84.1% of patients were men. Prevalence of prior coronary artery bypass graft surgery was 34.3%. Overall technical and procedural success were 90.1% and 88.7%, respectively. In-hospital major adverse cardiovascular events (MACE) occurred in 31 patients (2.4%). ADR was used in 458 cases (34.9%), and was the first strategy in 169 cases (12.9%). ADR cases were angiographically more complex than non-ADR cases (mean J-CTO score: 2.8±1.2 vs. 2.4±1.2, p CONCLUSIONS: ADR is used relatively frequently in contemporary CTO PCI, especially for challenging lesions and after failure of other strategies. ADR is associated with similar success rates and risk for complications as compared with AWE, and is important for achieving high procedural success

Equipment utilization in chronic total occlusion percutaneous coronary interventions: Insights from the PROGRESS-CTO registry

BACKGROUND: We examined guidewire and microcatheter utilization during chronic total occlusion (CTO) percutaneous coronary intervention (PCI). METHODS: We examined device utilization in 2,968 CTO PCIs performed in 2,936 patients at 19 US and two international center between January 2016 and January 2019. RESULTS: The median number of antegrade guidewires used per case declined (5 in 2016 vs 3 in 2019) and was higher in higher complexity lesions (2 in J-CTO 0 vs. 8 in J-CTO 4 or 5 score). In antegrade-only procedures, the most frequently used guidewires were the Pilot 200 (Abbott Vascular, 37%), Fielder XT (Asahi Intecc, 25%) and Gaia third (Asahi Intecc, 18%), while the most commonly used microcatheters were the Turnpike Spiral (Vascular Solutions, 18%) and Turnpike (Vascular Solutions, 16%). Compared with 2012-2015, during 2016-2019 use of novel equipment such as the Gaia guidewires and the Turnpike microcatheters led to decreased use of Confianza Pro 12 (Asahi Intecc) wire and Corsair (Asahi Intecc) family of microcatheters. In retrograde cases, the guidewires most commonly used were the Sion (44%), Pilot 200 (27%) and Fielder FC (26%), while the Corsair/Corsair Pro, Turnpike LP (Vascular Solutions) and Caravel (Asahi Intecc) were the most frequently used microcatheters for collateral crossing (29%, 26% and 22%, respectively). CONCLUSIONS: The most commonly used guidewires during CTO PCI are polymer-jacketed guidewires and the most commonly used microcatheters are torquable microcatheters