Recanalization of Complex Coronary Chronic Total Occlusions Using High‐Frequency Vibrational Energy CROSSER Catheter as First‐Line Therapy: A Single Center Experience

Background: Several studies have illustrated the safety and the procedural outcome of high‐frequency vibrational energy in guidewire refractory chronic total occlusions (CTOs). Aim: To evaluate the advantage of high‐frequency vibrational energy device (CROSSER Catheter) use in coronary complex CTO revascularization as primary strategy. Methods: CROSSER was used as a primary approach if four or more unfavorable angiographic features were observed in the CTO lesions. Results: From May 2007 to February 2009, a CTO percutaneous intervention attempt was performed in 178 lesions of 171 patients (60.1 ± 8.9 age with 49.4 ± 7.2% in ejection fraction). Among these, the CROSSER was used in 46 complex CTO lesions of 45 patients (25.8% of cases) and in the remaining cases, typical CTO percutaneous coronary intervention techniques were employed. Clinical success was 84.8% in CROSSER group. Moreover, in the CROSSER group, no periprocedural myocardial infarction, perforation, or 30 days MACE was observed. In addition, the use of CROSSER was associated with lower time of procedure, time of fluoroscopy, and contrast load administration as compared with conventional techniques [88 ± 27 minutes vs 109 ± 38 minutes (P = 0.045), 39 ± 12 minutes vs 50 ± 27 minutes (P = 0.032), and 334 ± 122cc vs 408 ± 198cc (P = 0.05), respectively]. Conclusion: In the present study, the CROSSER System was safe and obtained a high rate of success in complex CTO similar to conventional dedicated guidewire techniques for noncomplex CTO; however, the CROSSER Catheter obtained CTO recanalization with lower contrast load administration, less time of procedure, and lower fluoroscopy exposure. (J Interven Cardiol 2010;23:130‐138)     

A novel approach to chronic total occlusions: the crosser system.

OBJECTIVES: To evaluate safety and efficacy of the CROSSER CTO Recanalization System (CROSSER). BACKGROUND: The CROSSER, a novel device dedicated to recanalization of chronic total occlusions (CTO), relies on a monorail catheter delivering vibrational energy to facilitate the crossing of occluded coronary arteries. METHODS: We included de novo or restenotic occlusions in native coronary arteries with typically unfavorable characteristics and a prior failed guidewire attempt either performed in a previous procedure or just before the usage of the CROSSER. The end points analyzed were technical success (ability to cross or facilitate a guidewire crossing into the true lumen), angiographic success (<20% residual stenosis and TIMI flow grade 3), and clinical success (angiographic success and freedom from major adverse cardiac events at 30 days). RESULTS: Twenty-eight patients (30 lesions) were included. The morphology was blunt in 83.3% and the length of the occlusion was >20 mm in 76.6%. The median age of the CTO was 9 months (range 3-60 months). Technical success was obtained in 19 (63%) occlusions and angiographic success in 16 (53%): 26.3% in lesions with prior procedural failure and 73.7% when CROSSER was attempted after initial guidewire failure. Complications were: one guidewire perforation without consequences and one peri-procedural myocardial infarction (MI). No events occurred within 30-day follow-up after discharge. CONCLUSIONS: In our experience, the CROSSER System is safe and increases the success of opening CTO refractory to guidewires. This novel device may represent an useful adjunct to the armamentarium of the interventional cardiologist.     

Use of high‐frequency vibrational energy in the treatment of peripheral chronic total occlusions

Purpose: Peripheral chronic total occlusions (CTO) are challenging lesions to treat. The CROSSER system (FlowCardia, Sunnyvale, CA) uses high‐frequency low‐amplitude vibrations to break through the cap of the CTO and had been shown to be successful in coronary CTOs. This is a case series demonstrating the use of the CROSSER system with peripheral CTOs. Case Reports: Three patients with peripheral CTO of various lengths, locations, and complexities were treated with the CROSSER system. The device allowed placement of a guidewire across the area of occlusion, thus permitting further percutaneous intervention. The CROSSER system was effective with both ostial and distal lesions, tapered and abrupt lesion morphologies, and was used from both an ipsilateral (antegrade access) and contralateral approach. Conclusion: The CROSSER system is an additional device that may be used to treat peripheral CTOs. © 2009 Wiley‐Liss, Inc.     

Initial experience with a dedicated coronary re-entry device for revascularization of chronic total occlusions

Objective : The aim of this registry was to evaluate a new device designed to facilitate antegrade guidewire re‐entry into the true lumen of a chronic total coronary occlusion (CTO) from the adjacent subintimal space. Background : Successful recanalization of CTOs results in clinical improvement in appropriately selected patients. CTO intervention is time‐ and resource‐consuming, and a simplified approach enabling antegrade guidewire re‐entry into the distal true lumen might improve success. Methods : Patients with CTO and ischemia were entered into a prospective registry regardless of lesion characteristics. If wire manipulation resulted in subintimal wire entrapment, a new re‐entry tool (a 2.5‐mm flat subintimal balloon with two exit ports offset by 180°) was used as a platform to attempt guidewire penetration into the distal true lumen. The primary endpoint assessed was successful device‐guided re‐entry. Standard techniques were then utilized to open the CTO. Results : In 40 consecutive CTO lesions attempted, 19 resulted in subintimal wire entrapment (mean occlusion length 44 mm). Sixteen of these 19 were successfully crossed with an antegrade guidewire into the distal true lumen using the new device (84%). One patient with unsuccessful re‐entry was subsequently recanalized with a retrograde technique. All crossed lesions were stented (17/17), resulting in TIMI 3 flow without major complications. Two cases were unsuccessful. One patient had a grade I coronary perforation requiring no treatment. Conclusions : A new device to recanalize CTOs complicated by subintimal wire entrapment can be used successfully by experienced operators. Further study of this coronary re‐entry device is ongoing. © 2011 Wiley Periodicals, Inc.     

The revascular active percutaneous interventional device for coronary total occlusions study

Background. Despite the well‐documented benefit of recanalization of an occluded vessel in some symptomatic patients, attempt is only performed in a minority of them. Percutaneous coronary intervention (PCI) of CTO is associated with high incidence of complications and unsuccessful procedure, mainly due to inability to cross the lesion. We sought to evaluate the efficacy and safety of the novel RVT CTO Guidewire Device? (RVT‐GDW?, ReVascular Therapeutics, Sunnyvale, CA) in this complex scenario. Methods. The RAPID‐CTO study is a non‐randomized, single center, first‐in‐man evaluation of a new guidewire system for treatment of CTO. The RVT‐GDW is a new device designed to provide enhanced penetration and positioning control for crossing CTO via: (1) an 0.014 “guidewire with a mechanically active distal end; (2) a handle attached proximally to the guidewire, with an adjustable torquer, and interfaced to (3) a non‐disposable, battery‐operated, control unit, that provides activation control and audio feedback during the CTO crossing procedure. Per protocol, the RVT‐GDW device was only used after at least 5 min (fluoroscopy time) of attempt with commercially available conventional guidewires to cross the target lesion. Results. A total of 16 patients (16 lesions) were treated with the RVT‐GDW. Mean age was 56.25 years, 56.2% were men, and 25% diabetics. The average duration of occlusion was 4.7 ± 2.1 months. The mean vessel reference diameter was 2.76 ± 0.31 mm and the mean lesion length was 16.64 ± 7.70 mm (range 4.37–35.0 mm). Thirteen patients (81.2%) had “tapered stump” morphology at the proximal end of the occlusion, and a side branch was involved in 12 (75.0%). All lesions had contralateral circulation; bridging collaterals were seen in three (18.7%). Procedural success was achieved in 10 lesions (62.5%), with an average procedural time of 111.43 ± 35.76 min. There were no major adverse cardiac events at both in‐hospital and 30‐day clinical follow‐up. Conclusions. The first‐in‐man RAPID‐CTO study suggests that the novel RVT‐GDW device is technically feasible, safe and effective in crossing chronically occluded coronary arteries. Larger studies are warranted. © 2008 Wiley‐Liss, Inc.     

CTO recanalization by intraocclusion injection of contrast: The microchannel technique

Objectives : To assess the utilization of microinjection of contrast for the recanalization of chronic total occlusions (CTO). Background : Microchannels in CTOs have been considered important conduits for CTO crossing, utilizing dedicated guidewires. We postulated that microinjection of contrast immediately distal to the proximal cap of the CTO could identify and enlarge these microvessels, creating a passage for crossing the CTO with a floppy guidewire. Methods : A total of 32 patients with a CTO were treated with this technique. Following few millimetres penetration of the proximal fibrous cap of the occlusion with a dedicated CTO guidewire, the over‐the‐wire balloon was advanced into the proximal portion of the occlusion, and 50–100 μg of nitroglycerine followed by 1 ml of contrast was gently injected into the occluded segment. Technical success of the microchannel technique was defined as the ability to visualize the distal true lumen with microinjection of contrast and thereafter cross the CTO with a floppy guidewire in the absence of any dissection. Results : Overall, technical success of the microchannel technique was obtained in 20 (63%) with angiographic success in 19. In 12 (37%) cases there was a technical failure because of dissection, and we obtained recanalization of the artery in 7 of these 12 cases with another technique. There was only one case of periprocedural myocardial infarction in an unsuccessful procedure and no major adverse cardiac events or subacute stent thromboses were observed. Conclusions : Microinjection of contrast immediately distal to the proximal fibrous cap of a CTO may be an additional technique to facilitate recanalization of CTO. © 2008 Wiley‐Liss, Inc.     

Subintimal guidewire tracking during successful percutaneous therapy for chronic coronary total occlusions: Insights from an intravascular ultrasound analysis

Objectives : We sought to determine the frequency of subintimal guidewire tracking during successful percutaneous coronary intervention (PCI) for chronic coronary total occlusions (CTOs) and to better understand the procedural implications of this event. Background : Successful PCI for chronic CTO is associated with improved outcomes in patients with ischemia. While subintimal guidewire tracking resulting in failure to cross is recognized as the major mode of failure for CTO PCI, the implications of subintimal guidewire tracking during successful CTO PCI are unknown. Methods : Between March 2007 and October 2007, 26 consecutive patients, each with one de‐novo CTO lesion successfully crossed with a guidewire were included in the analysis. Intravascular ultrasound (IVUS) was performed in each CTO vessel after guidewire crossing. Cases were classified as having definite subintimal wire tracking or no clear evidence of subintimal wire tracking based on analysis of IVUS images. Results : Subintimal wire tracking occurred in 45% of cases. In cases where subintimal wire tracking was present, a previous attempt at CTO PCI was more common (42% vs. 7%, P ≤ 0.05). Subintimal wire tracking was also associated with significantly longer final mean stent length (71 vs. 50 mm), procedure time (122 vs. 69 min), fluoroscopy time (47 vs. 22 min), and contrast dose (300 vs. 199 mL, P ≤ 0.05 for all). There was one perforation in the subintimal group which was successfully treated with stent placement. Conclusions : Subintimal wire tracking occurs frequently during successful PCI for CTO and is associated with increased lesion and procedural complexity.© 2011 Wiley Periodicals, Inc     

Acute forearm muscle swelling post transradial catheterization and compartment syndrome: Prevention is better than treatment!

Objectives : To assess the application of rotational atherectomy to improving the success rate of percutaneous recanalization of chronic total occlusion (CTO). Background : Although the inability to cross the occlusion with a guidewire is the reason for failure in the majority of cases, one of the most frustrating situations that may occur during a recanalization procedure is when a guidewire crosses successfully but it is impossible to advance any device over the wire through the occluded segment. Methods : From January 2006 to October 2009, 45/648 (7%) consecutive patients with CTO resistant to recanalization by conventional techniques were treated by high‐speed rotational atherectomy (Rotablator group). Results : All but two lesions were successfully crossed by Rotablator and eventually treated by stent implantation. As compared to the 603 CTO treated by conventional techniques (Conventional group), the 45 patients in the Rotablator group were older, more often female, active smokers, with chronic kidney disease and higher rate of previous surgical revascularization. The CTO in the Rotablator group had a longer duration. Peri‐procedural myocardial infarction was more frequent in the Rotablator group (35% vs. 22%; P = 0.044). Coronary perforation occurred only in three patients in the Conventional group and two of these patients needed urgent surgical intervention. No patient died from either group. Conclusions : The inability to cross a CTO with a balloon catheter occurs in approximately 7% of all CTOs that are successfully crossed with a guidewire. Rotational atherectomy is a safe and effective technique to overcome this frustrating situation. © 2010 Wiley‐Liss, Inc.     

Collateral grading systems in retrograde percutaneous coronary intervention of chronic total occlusions

Background

The Japanese Channel (J-Channel) score was introduced to aid in retrograde percutaneous coronary intervention (PCI) of chronic total coronary occlusions (CTOs). The predictive value of the J-Channel score has not been compared with established collateral grading systems such as the Rentrop classification and Werner grade.

Aims

To investigate the predictive value of the J-Channel score, Rentrop classification and Werner grade for successful collateral channel (CC) guidewire crossing and technical CTO PCI success.

Methods

A total of 600 prospectively recruited patients underwent CTO PCI. All grading systems were assessed under dual catheter injection. CC guidewire crossing was considered successful if the guidewire reached the distal segment of the CTO vessel through a retrograde approach. Technical CTO PCI success was defined as thrombolysis in myocardial infarction flow grade 3 and residual stenosis <30%.

Results

Of 600 patients, 257 (43%) underwent CTO PCI through a retrograde approach. Successful CC guidewire crossing was achieved in 208 (81%) patients. The predictive value of the J-Channel score for CC guidewire crossing (area under curve 0.743) was comparable with the Rentrop classification (0.699, p = 0.094) and superior to the Werner grade (0.663, p = 0.002). Technical CTO PCI success was reported in 232 (90%) patients. The Rentrop classification exhibited a numerically higher discriminatory ability (0.676) compared to the J-Channel score (0.664) and Werner grade (0.589).

Conclusions

The J-channel score might aid in strategic collateral channel selection during retrograde CTO PCI. However, the J-Channel score, Rentrop classification, and Werner grade have limited value in predicting technical CTO PCI success.     

Use of the venture wire control catheter for the treatment of coronary artery chronic total occlusions

Background : The Venture catheter (St Jude, Minneapolis, MN) has a deflectable tip for facilitating wire steering and a stiff body. Both properties can be useful in percutaneous coronary interventions (PCI) of coronary chronic total occlusions (CTOs). Methods : We reviewed 26 consecutive patients in whom the Venture catheter was utilized during coronary CTO PCI at our institution between May 2008 and September 2009. Results : Mean age was 63 ± 9 years and 96% of the patients were men. The CTO target lesion was located in the right coronary artery (35%), left anterior descending artery (27%), circumflex (27%) or a saphenous vein graft (4%). A prior attempt for CTO PCI had been done in 19%. The primary CTO PCI approach was antegrade in 92% and retrograde in 8%, but a retrograde approach was used in an additional 27% of the patients after antegrade approach failed. The Venture catheter was used to overcome vessel tortuosity (73%), for CTOs with side branch at the occlusion site (15%), to facilitate collateral branch wiring during retrograde PCI (8%), and to provide extra support (4%). The overall CTO PCI success rate was 77% and was 92% in patients with upfront Venture catheter use and in 64% of patients in whom the Venture was used after PCI attempts using other equipment failed. Procedural failure was due to inability to cross the lesion in all cases. Conclusions : The Venture catheter can facilitate CTO PCI, especially in patients with marked coronary tortuosity or when additional support is required. © 2010 Wiley‐Liss, Inc.     

Coronary septal collaterals as an access for the retrograde approach in the percutaneous treatment of coronary chronic total occlusions.

OBJECTIVES: To investigate the feasibility and safety of the percutaneous dilatation of coronary septal collaterals and to allow its use as an access for retrograde approach to percutaneous coronary intervention (PCI) of coronary chronic total occlusions (CTOs). BACKGROUND: Despite improvements in percutaneous techniques and materials, CTO recanalization success rate is still suboptimal. The retrograde approach allows to significantly increase this success rate. However, its application via a bypass graft or epicardial collateral can potentially result in severe complications. A safer retrograde access is desired and would allow broadening the application of the retrograde approach in the percutaneous treatment of CTOs. METHODS: After a failed antegrade CTO recanalization attempt, a retrograde approach via septal collaterals was tried in 21 patients (19 males, 2 females). The septal collateral was accessed via the contralateral patent coronary artery and was crossed with a hydrophilic floppy wire. After successful wire crossing of the septal collateral, sequential low pressure dilatation was performed with a 1.25 or 1.5 mm balloon to allow the delivery of a balloon catheter up to the distal CTO site. RESULTS: Successful wire crossing and balloon dilatation of septal collaterals was achieved in 19 cases and in 17 cases, respectively. Postdilatation septal collateral diameter increased significantly reaching a mean diameter of 1.46 +/- 0.38 mm. Retrograde CTO recanalization was successfully performed in 71% of the cases. No major complications occurred. CONCLUSIONS: Coronary septal collaterals can be used as an access for the retrograde approach in the percutaneous treatment of CTOs.     

A prospective multicenter registry of 0.010‐inch guidewire and compatible system for chronic total occlusion: The PIKACHU registry

Objectives : The aim of this study was to evaluate the safety and effectiveness of a 0.010‐inch guidewire and a balloon catheter for treatment of chronic total occlusion (CTO). Background : Pathological studies have shown that 60–70% of CTO lesions have microchannels of sizes equal to or less than 0.010 inch. Methods : The PIKACHU registry is a prospective, multicenter registry study. A 0.010‐inch guidewire had to be used as the first guidewire to attempt to pass the CTO lesion. The primary endpoint was device success using a 0.010 system. Results : A total of 141 patients with 141 lesions were enrolled. The median duration of occlusion was 9 months (range 3–156). Average guiding catheter size was 5.8 ± 0.7 Fr. and TRI was 76.6 %. CTOs were mostly between 10–20 mm long, observed in 53 occlusions. There were 107 lesions (75.9%) with bending of more than 45 degrees. Calcification was seen in 91 lesions (64.5%). A 0.010‐inch guidewire was successfully passed through in 97 of 141 lesions (68.8%). A 0.010‐inch guidewire compatible balloon catheter was passed in 87 of the 97 lesions (88.7%) and final PCI success was achieved in all the cases. The overall clinical success rate was 87.9% (124/141). No MACE or bleeding complications were observed. Conclusion : The PIKACHU registry data suggest that the 0.010‐inch system is safe and practicable for treatment of CTO lesions. © 2010 Wiley‐Liss, Inc.     

Percutaneous coronary interventions and cardiovascular outcomes for patients with chronic total occlusions

相似文献   

A novel approach to facilitating balloon crossing chronic total occlusions: the "wire-cutting" technique

Background: Following successful guidewire passage, inability to cross the occluded lesion with a balloon is the most common cause of procedural failure for percutaneous recanalization of chronic total occlusions (CTOs). We sought to evaluate the efficacy of “wire‐cutting” technique for facilitating the balloon passage through the lesion during CTO‐percutaneous coronary intervention. Methods: Sixteen consecutive patients with CTOs were treated by “wire‐cutting” technique when a lubricious balloon could not be passed through the lesion after successful guidewire crossing. The main process of the “wire‐cutting” technique involved: inserting 2 percutaneous transluminal coronary angioplasty (PTCA) guidewires (A and B) into the distal true lumen; advancing a balloon over guidewire A to the site of the occlusion abutting the proximal cap, the balloon was then inflated and guidewire B was pressed between the balloon and the proximal cap; rapidly withdrawing guidewire B produced a cutting power that crushed the proximal cap thus facilitating balloon crossing. Technique success was defined as balloon having crossed CTO lesions successfully after performing wire‐cutting procedure. Results: Both technical success and procedural success were obtained in 10 (62.5%) cases. Technique failure occurred in 6 (37.5%) cases, of which 2 were due to the inability to place a second guidewire into the distal true lumen and the other 4 were due to severe coronary calcification. Of these 4 failures, 2 have final procedure success with the use of Rotablator and the remaining 2 patients were referred for bypass surgery. Major complication included severe coronary dissection that occurred in 1 (6.3%) patient, which was successfully treated by stenting. No other complications were observed. Conclusion: The wire‐cutting technique may be considered as a simple and effective approach for facilitating balloon crossing resistant CTO lesions. (J Interven Cardiol 2012;25:297–303)     

Contrast modulation in chronic total occlusion percutaneous coronary intervention

The intraplaque injection of contrast media in the recanalization of coronary chronic total occlusions (CTO) has witnessed a dynamic journey since its initial formulation. Contrast‐guided subintimal tracking and re‐entry (STAR) was the first contrast modulation technique for CTO percutaneous coronary intervention (PCI). With this technique, a forceful injection of a large volume of contrast (3–4 mL) was performed in order to achieve hydraulic recanalization of the vessel. This approach was associated with extensive vessel injury and unpredictable true lumen re‐entry, which were in turn linked to high rates of restenosis on follow‐up. In the subsequent iteration, called the “microchannel technique”, a smaller amount of contrast media (1 mL) was gently injected inside the plaque to modify its compliance by softening and recruiting loose tissue, which facilitated subsequent true‐to‐true lumen crossing with a polymer‐jacketed wire along paths of least resistance. The microchannel technique has later evolved into what is currently known as the “Carlino technique”, where a minimal volume of contrast media (<0.5 mL) is gently injected inside the occlusion, with the goal of modifying plaque compliance to facilitate guidewire and microcatheter advancement through a fibrocalcific plaque. The Carlino technique is now widely utilized to allow negotiation of difficult‐to‐cross occlusions, particularly by the “hybrid operators”, with high success rates and low incidence of complications. The purpose of this article is to provide a historical perspective on the use of contrast modulation in CTO PCI, its pathophysiological basis, as well as technical recommendations on how and when to perform these maneuvers.     

Successful use of the frontrunner catheter in the treatment of in-stent coronary chronic total occlusions.

Percutaneous intervention of coronary chronic total occlusion (CTO) from in-stent restenosis (ISR) is hindered by difficulty to cross the lesion with conventional guidewires. This study describes the successful treatment of five cases of CTOs from ISR using the Frontrunner controlled blunt microdissection catheter. Four of the five cases had failed previous attempts of percutaneous intervention with conventional guidewires. The Frontrunner catheter successfully facilitated the placement of guidewire into the distal true lumen in all five cases. The median crossing time was 10 min. No subintimal delivery of guidewire or vascular perforation was observed. TIMI 3 flow was achieved in all target vessels after further balloon angioplasty or stenting. The Frontrunner device is a safe and effective tool in the treatment of CTOs from ISR.     

Different strategies of retrograde approach in coronary angioplasty for chronic total occlusion

Background:

Retrograde approach through the collateral channels has been recently proposed and has the potential to improve the success rate of percutaneous coronary intervention (PCI) in chronic total occlusion (CTO) lesions of the coronary arteries.

Methods:

The author performed retrograde approach for CTO lesions in 45 patients from January 2006 to January 2007 at different medical institutions worldwide. The details of the techniques were examined retrospectively.

Results:

The septal branch route was used in 93% of the cases. The author classified the strategies into six types after the successful crossing of a guidewire into the target artery distal to the CTO lesion through the collateral channels. Among them, “Just landmark,” “Controlled antegrade and retrograde subintimal tracking,” and “Proximal true lumen puncture” strategies were used most frequently (32, 27, and 30%, respectively). The retrograde guidewires could be successfully passed distal to the CTO lesion in 37 patients (82%), among them the final PCI success was achieved in 31 patients, yielding the PCI success by pure retrograde approach of 69%. The final success rate among 45 patients including 42 patients with previous failed attempts was 84% (38 patients). There were no serious complications related to the retrograde approach.

Conclusions:

Retrograde approach with different strategies, mainly through septal arteries, can provide a high success rate with PCI, as shown in 83% of patients with previous failed attempts at traditional PCI for CTO lesions, with there being no serious complications. More experience of this technique and its refinement are required for further improvement of PCI techniques for CTO lesions. © 2008 Wiley‐Liss, Inc.     

Guidewire navigation in coronary artery stenoses using a novel magnetic navigation system: first clinical experience.

The objective of this study was to investigate the efficacy of guidewire navigation across coronary artery stenoses using magnetic navigation system (MNS) versus conventional navigation. The MNS is a novel option to facilitate access to target lesions, particularly in tortuous vessels. In an experimental study using a challenging vessel phantom, magnetic-navigated guidewire passage has been reported to reduce fluoroscopy and procedure time significantly. Both magnetic and manual guidewire navigation were attempted in 21 consecutive diseased coronary arteries. The study endpoint was defined as an intraluminal wire position distal to the stenosis. Procedural success was defined as successful guidewire passage without procedural events. Procedure time, amount of contrast, fluoroscopy time, and radiation dose/area product (DAP) were evaluated. There were no procedural events related to either guidewire. Although the lesions attempted had relatively simple and straightforward characteristics, significantly shorter procedure and fluoroscopy time were observed for manual guidewire navigation compared to MNS (median, 40 vs. 120 sec, P=0.001; 38 vs. 105 sec, P=0.001, respectively). Contrast amount and DAP were higher in MNS than in conventional method (median, 13 vs. 9 ml, P=0.018; 215 vs. 73 Gym2, P=0.002, respectively). The magnetic wire did not cross in two vessels. Guidewire navigation using MNS presented a novel, safe, and feasible approach to address coronary artery lesions. Clinical studies are needed to evaluate the potential benefit of the MNS in more complex coronary lesions and tortuous anatomy.     

Therapeutic ultrasound for chronic total coronary artery occlusions

This article focuses on the use of catheter-delivered ultrasound as a device for treatment of coronary arterial total occlusion (CTO). The standard treatment of CTO is reviewed and serves as the basis for the need for new treatment options, such as catheter-delivered ultrasound (SONICROSS). The results of FDA-approved Phase I and Phase II clinical trials using SONICROSS for refractory CTO are described. The Phase II trials indicate that the SONICROSS-facilitated guidewire passage in 71% of CTOs are otherwise refractory to guidewire passage. However, at present, the SONICROSS catheter system is limited in its ability to be delivered reliably to the CTO because of catheter size and trackability.