The CathCam: A Novel Angioscopic Solution for Endovascular Interventions.

Peripheral arterial diseases are commonly managed with endovascular procedures, which often face limitations in device control and visualization under X-ray fluoroscopy guidance. In response, we developed the CathCam, an angioscope integrated into an expandable cable-driven parallel mechanism to enhance real-time visualization, precise device positioning and catheter support for successful plaque crossing. The primary objective of this study was to assess and compare the performance of the novel CathCam with respect to conventional catheters and the CathPilot (i.e., CathCam without the angioscope), for applications in crossing chronic total occlusions (CTO). We first assessed the system in 3D-printed phantom models, followed by an ex vivo evaluation with CTO samples from a patient's superficial femoral artery. We measured and compared success rates, crossing times, and fluoroscopy times in both experiments. The CathCam demonstrated a 100% success rate in phantom experiments and a 75% success rate in ex vivo experiments with CTO samples, compared to conventional catheters, with 35% and 25% success rates, respectively. The average crossing times for the CathCam and the conventional catheter were 31 s and 502 s for the phantom experiments and 210 s and 511 s for the actual CTO lesions. The Cathcam also showed to be a reliable endovascular imaging approach in an in vivo experiment. Compared to conventional catheters, the CathCam significantly increased the success rate and reduced crossing and fluoroscopy times in both phantom and ex vivo setups. CathCam can potentially improve clinical outcomes for minimally invasive endovascular interventions by offering high-resolution real-time imaging alongside accurate device control.

Angioscopic evaluation after venous stents.

BACKGROUND: Venous stenting is increasingly used to manage femoro-ilio-caval venous outflow obstruction/stenosis due to post-thrombotic syndrome. Although the safety, efficacy, and long-term patency of venous stents have been reported, re-interventions due to stent occlusion and in-stent restenosis (ISR) have also been reported. The mechanism of ISR and the in-stent neointimal growth after venous stenting remains unclear. We performed angioscopy to evaluate intraluminal details after venous stenting, allowing real-time direct visualization of the vessel lumen. METHODS: Ten angioscopic procedures in four patients with post-thrombotic syndrome were performed. All evaluated vessels were stented iliac veins, and their native pathology was chronic post-thrombotic occlusion. Nine procedures in three patients underwent serial evaluation of the neointimal changes after stent implantation to study the natural time course of neointimal proliferation/coverage over the stent. The serial follow-up angioscopic evaluations were performed at the end of the venous stent deployment procedure, and at 6 months, 12 months, and 24 months. One procedure was performed 1 month after the stent implantation to evaluate ISR, which was observed at the first month of routine stent surveillance. A 5.7F angioscope was used to visualize the target veins. Continuous irrigation was used to displace blood and clear the visual field. RESULTS: At 6 months after stent implantation, stent struts were covered by a thin neointima in two of the three patients. The struts were partially covered in one patient, but there was little neointimal growth overall. Neointimal coverage increased over time, and at 12 months stent struts in 2 patients were almost completely covered. There was no significant change between the 12 and 24 months after stent implantation. In the ISR case, angioscopy demonstrated an overgrown thickened neointima, and the stent struts were fully embedded and invisible in the entire stented area. No thrombus and no webs or trabeculae were found in the area evaluated as an ISR lesion. CONCLUSIONS: At 6 months after stent placement, the stent struts were almost covered by a neointima. The stent struts were completely covered 1 year after stent implantation. Neointimal coverage was unchanged from the 1-year follow-up to the 2-year follow-up, suggesting that neointimal proliferation proceeded gradually with subsequent neointimal remodeling up to 1 year. The cause of ISR might be the overgrown thickened neointima rather than the formation of thrombosis.

Applications of a Novel Microangioscope for Neuroendovascular Intervention.

BACKGROUND AND PURPOSE: Visualization in neuroendovascular intervention currently relies on biplanar fluoroscopy and contrast administration. With the advent of endoscopy, direct visualization of the intracranial intravascular space has become possible with microangioscopes. We analyzed the efficacy of our novel microangioscope to enable direct observation and inspection of the cerebrovasculature, complementary to a standard fluoroscopic technique. MATERIALS AND METHODS: Iterations of microangioscopes were systematically evaluated for use in neurodiagnostics and neurointerventions in both live animal and human cadaveric models. Imaging quality, trackability, and navigability were assessed. Diagnostic procedures assessed included clot identification and differentiation, plaque identification, inspection for vessel wall injury, and assessment of stent apposition. Interventions performed included angioscope-assisted stent-retriever thrombectomy, clot aspiration, and coil embolization. RESULTS: The microangioscope was found helpful in both diagnosis and interventions by independent evaluators. Mean ratings of the imaging quality on a 5-point scale ranged from 3.0 (clot identification) to 4.7 (Pipeline follow-up). Mean ratings for clinical utility ranged from 3.0 (aspiration thrombectomy) to 4.7 (aneurysm treatment by coil embolization and WEB device). CONCLUSIONS: This fiber optic microangioscope can safely navigate and visualize the intravascular space in human cadaveric and in vivo animal models with satisfactory resolution. It has potential value in diagnostic and neurointerventional applications.

High-Resolution Scanning Fiber Angioscopy as an Adjuvant to Fluoroscopy During Endovascular Interventions.

PURPOSE: To demonstrate the feasibility and potential utility of high-resolution angioscopy during common endovascular interventions. METHODS: A 3.7-F scanning fiber angioscope was used in 6 Yorkshire pigs to image branch vessel selection, subintimal dissection, wire snaring, and stent placement. The angioscope was introduced in a coaxial fashion within a standard 6-F guide catheter. A clear field of view was provided using continuous heparinized saline flush through the outer guide catheter. The flush flow rate was manually adjusted to provide clear imaging depending on the diameter of the vessel and local blood flow conditions. RESULTS: The scanning fiber angioscope was compatible with off-the-shelf catheters and devices commonly used in peripheral and aortic interventions. Video-rate, high-resolution images were obtained during all the interventions tested and provided information that was complementary to simultaneously acquired fluoroscopy. The scanning fiber angioscope was able to detect subintimal dissection and branch vessel stent coverage with higher resolution than fluoroscopy alone. CONCLUSION: Endoluminal imaging with the scanning fiber angioscope is feasible with current endovascular devices and provides additional relevant information that cannot be assessed fluoroscopically. The scanning fiber angioscope represents a novel optical platform on which new endovascular techniques may be developed that will minimize radiation and contrast doses for patients.

Augmented reality system for freehand guide of magnetic endovascular devices.

Magnetic guide of endovascular devices or magnetized therapeutic microparticles to the specific target in the arterial tree is increasingly studied, since it could improve treatment efficacy and reduce side effects. Most proposed systems use external permanent magnets attached to robotic manipulators or magnetic resonance imaging (MRI) systems to guide internal carriers to the region of treatment. We aim to simplify this type of procedures, avoiding or reducing the need of robotic arms and MRI systems in the surgical scenario. On account of this we investigated the use of a wearable stereoscopic video see-through augmented reality system to show the hidden vessel to the surgeon; in this way, the surgeon is able to freely move the external magnet, following the showed path, to lead the endovascular magnetic device towards the desired position. In this preliminary study, we investigated the feasibility of such an approach trying to guide a magnetic capsule inside a vascular mannequin. The high rate of success and the positive evaluation provided by the operators represent a good starting point for further developments of the system.

Vascular microanastomosis through an endoscopic approach: feasibility study on two cadaver forearms.

The size of the incisions for free muscle flaps is often very large, and a source of deep adhesions and unaesthetic scars. But it is justified by performing the microsurgical step comfortably. In the hopes of shortening the size of incisions, the goal of this work was to study the feasibility of vascular microanastomoses through an endoscopic approach. The material consisted of two cadavers, a telemanipulator, and a vascular clamp. The antebrachial skin was detached then distended by gas insufflation. Four incisions, 1cm each, allowed the insertion of four trocarts connected to the telemanipulator. The artery was dissected (radial or ulnar) and the vascular clamp was introduced under the skin through one of the trocarts, and then installed on the dissected artery. The vascular anastomosis was performed with the use of a 10/0 nylon suture. The anastomosis lasted 2 hours under insufflation without any leak. The two arteries were identified then dissected without difficulty. The anastomosis was performed in good conditions. The assembling and disassembling of the clamp were time consuming. The main difficulties were caused by a long suture and a very fragile needle. Our results demonstrate the feasibility of vascular microanastomosis through an endoscopic approach. The next step is to perform the first clinical case for example on a latissimus dorsi free muscle flap.

Coronary angioscopic findings 9 months after everolimus-eluting stent implantation compared with sirolimus-eluting stents.

OBJECTIVES: We assessed angioscopic findings after everolimus-eluting stents (EES) implantation, compared with sirolimus-eluting stents (SES). BACKGROUND: Coronary angioscopy (CAS) provides an opportunity to assess neointimal coverage over stent struts, thrombus, and plaque color by direct visualization. CAS is a useful tool for evaluating stent struts after drug-eluting stent implantation. Angioscopic findings after EES implantation have not been reported before. METHODS: We performed CAS in 23 patients who were treated with EES and 41 patients with SES. CAS was performed 8.5 months after stent implantation. We assessed neointimal coverage, thrombus, and plaque color. We classified neointimal coverage in 4 grades: grade 0=struts were completely exposed; grade 1=struts were visible with dull light reflexion; grade 2=there was no light reflexion from slightly visible struts; grade 3=struts were completely covered. RESULTS: There was no significant difference in minimum, maximum, dominant grade of neointimal coverage, and heterogeneity index between EES and SES. Thrombus was less frequently observed in EES than SES (4% vs 29%, p=0.02). When we divided study patients into acute coronary syndrome (ACS) or stable angina pectoris (SAP), there was a tendency toward less thrombus in EES than SES, in both ACS and SAP. Maximum color grade of the plaques was less advanced in EES than SES (p<0.01). Yellow plaques of grade 2 or 3 were less frequent in EES than SES (35% vs 76%, p<0.01). CONCLUSIONS: This study suggested that EES were associated with lower risk of thrombus formation than SES.

[Successful application of cholangioscope as an intravascular endoscope in hybrid operation for a child].

We performed hybrid operation on a 3-year-old boy with thrombosis in the pulmonary arterial conduit which had been implanted concomitantly at the time of Fontan operation. We used a cholangioscope as a substitute of intravascular endoscope. It visualized the organized thrombus and the suture line in the conduit. Hybrid operation was successfully performed based on the detailed findings gained by cholangioscopy.

Towards real-time intravascular endoscopic magnetic resonance imaging.

Fast, minimally invasive, high-resolution intravascular imaging is essential for identifying vascular pathological features and for developing novel diagnostic tools and treatments. Intravascular magnetic resonance imaging (MRI) with active internal probes offers high sensitivity to pathological features without ionizing radiation or the limited luminal views of conventional X-rays, but has been unable to provide a high-speed, high-resolution, endoscopic view. Herein, real-time MRI endoscopy is introduced for performing MRI from a viewpoint intrinsically locked to a miniature active, internal transmitter-receiver in a clinical 3.0-T MRI scanner. Real-time MRI endoscopy at up to 2 frames/s depicts vascular wall morphological features, atherosclerosis, and calcification at 80 to 300 µm resolution during probe advancement through diseased human iliac artery specimens and atherosclerotic rabbit aortas in vivo. MRI endoscopy offers the potential for fast, minimally invasive, transluminal, high-resolution imaging of vascular disease on a common clinical platform suitable for evaluating and targeting atherosclerosis in both experimental and clinical settings.

Deep venous external valvuloplasty using a rigid angioscope.

PURPOSE: The aim of this study was to evaluate the long-term results of deep venous valvuloplasty using a rigid metal angioscope. METHODS: Forty patients who underwent deep venous external valvuloplasty using a rigid metal angioscope for primary deep venous insufficiency were enrolled. The preoperative CEAP (Clinical/Etiology/Anatomy/Pathophysiology) classifications were class 2 in 13 patients, class 3 in 8 patients, class 4 in 12 patients, class 5 in 1 patient, and class 6 in 6 patients. In 9 legs in 6 patients, the valves were either destroyed or congenitally absent, and deep venous plication was applied instead. The long-term operative results were evaluated from clinical charts and direct telephone interviews. RESULTS: During a mean follow-up period of 5.0 years, we experienced no deep vein thromboses or other complications. In 39 of the 40 patients, the subjective symptoms improved. The improvement after successful valvuloplasty was 82% with respect to the CEAP classification. Among the 9 legs treated by deep venous plication alone, 5 had improved CEAP classifications, while 4 showed no change. CONCLUSIONS: Deep venous external valvuloplasty assisted by a rigid angioscope is a safe and effective method for severe valve insufficiency. Furthermore, the long-term results are positive. Deep venous plication may therefore represent an effective alternative for patients who cannot undergo valvuloplasty.

Imaging of lysophosphatidylcholine in human coronary plaques by color fluorescence angioscopy.

Lysophosphatidylcholine (LPC) is a proinflammatory and proatherogenic substance, and it plays an important role in the initiation, progression, and destabilization of atherosclerotic plaques. If LPC in the vascular wall is visualized in vivo, the mechanisms of atherosclerosis and the effects of medical and interventional therapies on atherosclerosis can be objectively evaluated. Therefore, this study was carried out to visualize LPC in human coronary plaques using a color fluorescence angioscopy (CFA) system. (1) The fluorescence characteristics of LPC were investigated by color fluorescence microscopy (CFM) using Trypan blue dye (TB) as an indicator. For fluorescence imaging, a combination of a band-pass filter (345 nm) and a band-absorption filter of 420 nm (A imaging), or a combination of a band-pass filter (470 nm) and a band-absorption filter of 520 nm (B imaging) was employed. (2) The fluorescence of LPC in the excised human coronary plaques was investigated by CFA and CFM scanning using the same filters as those in CFM. In the presence of TB, LPC exhibited a red fluorescence in both A and B imaging. This red fluorescence color in both A and B imaging was not observed for the other known major substances that constitute the atherosclerotic plaques. This red fluorescence color in both A and B imaging was detected by CFA in both white and yellow plaques that were classified by conventional angioscopy. This fluorescence color was found to be distributed in a web-like or diffuse configuration by CFM scanning. LPC in the human coronary plaques was successfully visualized by CFA using TB as an indicator.

Angioscopy--a valuable tool in guiding hybrid stent grafting and decision making during type A aortic dissection surgery.

During hypothermic circulatory arrest (HCA), a briefly visible descending aorta is exposed, enabling direct vision to the surgeon. This study evaluated the impact of angioscopy on arch and descending aortic surgery for type A aortic dissection (AD). From December 2007 to March 2009, a flexible bronchovideoscope was used in 21 patients to assure true lumen (TL) positioning of the arterial cannula during open vision aortic cannulation (OVAC; nine of 21 cases) and to inspect the arch and descending aorta for re-entries, guide wire position and target zone for hybrid stent graft (SG) landing (20 of 21 cases). In OVAC, angioscopy secured positioning of the arterial cannula within the TL requiring additional 10-15s of cerebral ischaemia. In 10 of 21 cases, no additional re-entries were found, thus obviating arch replacement in 2 of 21 and stent grafting in 8 of 21. In 11 of 21 cases, SG deployment was guided to the target zone, in three cases incomplete unfolding initiated balloon dilatation. Angioscopy has become an indispensable tool for decision making in AD to apply OVAC, downstream stent grafting and landing zone control with the ability to indicate ballooning at neglectable time requirements during HCA.

MRI endoscopy using intrinsically localized probes.

Magnetic resonance imaging (MRI) is traditionally performed with fixed externally applied gradient magnetic fields and is hence intrinsically locked to the laboratory frame of reference (FoR). Here a method for high-resolution MRI that employs active, catheter-based, tiny internal probes that utilize the spatial properties of the probe itself for localization is proposed and demonstrated at 3 T. Because these properties are intrinsic to the probe, they move with it, transforming MRI from the laboratory FoR to the FoR of the device itself, analogous to an endoscope. The "MRI endoscope" can utilize loop coils and loopless antennas with modified sensitivity, in combination with adiabatic excitation by the device itself, to restrict the MRI sensitivity to a disk-shaped plane a few mm thick. Excitation with the MRI endoscope limits the eddy currents induced in the sample to an excited volume whose size is orders of magnitude below that excited by a conventional body MRI coil. Heat testing shows maximum local temperature increases of <1 degrees C during MRI, within regulatory guidelines. The method is demonstrated in a kiwifruit, in intact porcine and rabbit aortas, and in an atherosclerotic human iliac artery specimen, with in-plane resolution as small as 80 microm and 1.5-5 mm slice thickness.

Endovascular infrarenal abdominal aortic aneurysm repair.

Abdominal aortic aneurysm repair has undergone a revolution since Volodos and Parodi described endoluminal repair in the early 1990s. Subsequent data from large registries have confirmed its efficacy. Randomised controlled trials have shown that although endoluminal repair may not be as cost effective as open repair, it can be performed with a lower mortality in patients fit for open repair. Some European countries (eg, Belgium) have taken the results of these trials to rationalise the number of hospitals able to do endovascular repair. The devices continue to improve and although most require open surgical access at present, in future percutaneous access will become the norm. This article reviews the current state of endoluminal aortic aneurysm repair in the infrarenal aorta.

Characterization of human coronary sinus valves by direct visualization during biventricular pacemaker implantation.

BACKGROUND: The precise reasons for failure to cannulate the coronary sinus during biventricular device implantation are unknown. Visualization of the coronary sinus ostium during electrophysiology procedures may enhance understanding of how unusual anatomy can affect successful cannulation of the coronary sinus. OBJECTIVES: The aim of this study was to describe the morphology of valves at the coronary sinus ostium (CSO) visualized directly with an illuminated fiberoptic endoscope during implantation of biventricular devices. METHODS: The coronary sinus anatomy of one hundred consecutive patients undergoing implantation of biventricular devices was investigated using a fiberoptic endocardial visualization catheter (EVC). RESULTS: The CSO was clearly visualized in 98 patients using the EVC. A Thebesian valve was seen in 54% of these. Almost all Thebesian valves were positioned at the inferior (61%) or posterior (33%) aspect of the CSO. Only six patients had Thebesian valves that covered more than 70% of the CSO, but all were successfully implanted with a transvenous left ventricular pacing lead after cannulating the coronary sinus under direct visualization. CONCLUSIONS: Over half of patients undergoing biventricular device implantation have identifiable Thebesian valves. Even valves covering the majority of the ostial area may be traversed using direct visualization and modern catheterization techniques.

Prospective randomized study comparing the Teleflex Medical SaphLITE Retractor to the Ethicon CardioVations Clearglide Endoscopic System.

BACKGROUND: Several minimally invasive saphenous vein harvesting techniques have been developed to reduce morbidities associated with coronary artery bypass grafting. This prospective, randomized study was designed to compare two commonly used minimally invasive saphenous vein harvesting techniques, the SaphLITE Retractor System (Teleflex Medical) and the Clearglide Endoscopic Vessel Harvesting System (Ethicon CardioVations, Inc.). METHODS: Between January 2003 and March 2004, a total of 200 patients scheduled for primary, nonemergent coronary artery bypass grafting, with or without concomitant procedures were randomized into two groups: SaphLITE (n = 100) and Clearglide (n = 100). Pre-, intra- and postoperative data was collected and subjected to statistical analysis. Randomization provided homogenous groups with respect to preoperative risk factors. RESULTS: Harvest location for the SaphLITE group was thigh (n = 40), lower leg (n = 5) and both lower leg and thigh (n = 55). The location of harvest for the Clearglide group was thigh (n = 3), lower leg (n = 16) and both lower leg and thigh (n = 81). The mean incision length was 3.6 cm (range, 2-6) in the SaphLITE group versus 2.1 cm (range, 1-4) in the Clearglide group (p < 0.05). The total incision length was 12.9 cm versus 8.9 (p < 0.05) in the SaphLITE and Clearglide groups. Conversion to the open technique occurred in 5 SaphLITE patients and 7 Clearglide patients. Intraoperative leg exploration for bleeding occurred in two of the Clearglide patients and none of the SaphLITE patients. Post-operative complications specifically related to minimally invasive harvesting technique, including a two-week post-discharge visit, were not statistically different between the groups. CONCLUSION: The saphenous vein can be safely harvested utilizing the SaphLITE and Clearglide systems. While the Clearglide system allows for fewer incisions (number and length) and less harvest time, these benefits may be outweighed by the increased cost of the Clearglide system compared to the SaphLITE retractor.

Early human experience with use of a deflectable fiberoptic endocardial visualization catheter to facilitate coronary sinus cannulation.

BACKGROUND: Despite improvements in cardiac resynchronization therapy (CRT) implantation techniques, a significant minority of CRT attempts are unsuccessful. Inability to cannulate the coronary sinus (CS) because of difficult anatomy is a major reason for unsuccessful CRT implantation. Direct visualization of intracardiac structures during the implant may facilitate access into the CS. The present study describes CRT implantation with the aid of an endocardial visualization catheter (EVC). METHODS: Fifty-eight consecutive patients (mean age 72 +/- 12 years; ejection fraction 26.2% +/- 7.0%; New York Heart Association [NYHA] class 2.9) underwent CRT implantation using a steerable fiberoptic EVC (Acumen Medical, Inc., Sunnyvale, CA). RESULTS: The EVC was able to visualize the CS ostium in all cases. The CS was successfully cannulated in 57 (98.3%) of 58 patients. The time from vascular access to CS visualization was 6 +/- 5 minutes, and the total time to CS access was 8 +/- 6 minutes. Successful left ventricle (LV) lead implantation was accomplished in 55 (94.8%) of 58 patients. Three patients who had a previous history of failed LV lead implantation were successfully implanted using the EVC. CONCLUSION: Fiberoptic imaging of intracardiac structures during CRT implantation may be performed rapidly in a wide range of patients with an EVC. The ability to visualize right atrial anatomy may aid CS access and LV lead implantation.

[Initial experience in endoscopic radial artery harvesting].

We report the initial experience of endoscopic radial artery (RA) harvesting (ERA) using Vasoview System. The expected advantages of ERA are superior cosmetic results and fewer wound complications to the conventional open technique. ERA was performed in 33 patients from September 2004 to September 2005. Preoperatively, Allen's test with Doppler imaging was performed in all patients. ERA was successfully performed within 50 minutes except in the first 3 patients (the mean time for harvest: 37 minutes). Direct injury of the RA occurred in 1 patient, but the RA could be used as a graft for coronary artery bypass grafting (CABG) by repairing with end-to-end anastomosis. Only 1 RA graft occluded as determined by the early postoperative angiography. Local dissection of the RA was observed in 2 patients, but no flow disturbance was observed. Delayed wound healing occurred in 1 aged patient. No significant nerve complications were encountered. ERA is easy to adopt and has greater cosmetic advantages.