Endovascular robotics

The current state and the future direction.

Rapid induction of brain hypothermia by endovascular intra-arterial perfusion

OBJECTIVES

Achieving rapid, brain cooling has potentially important clinical implications. To investigate potential practicalities, we induced brain hypothermia in canines by perfusing cooled crystalloid solution into the carotid artery using an extracorporeal cooling-filtration system.

METHODS

Ringer's solution cooled to approximately 6.5 degrees C was infused at a rate of 3 ml/kg/min for 30 minutes into the right common carotid artery through an angiographic catheter via the right femoral artery in six adult canines (13.81 +/- 0.60 kg). Excessive fluid was ultrafiltrated through a venovenous extracorporeal circuit via the right femoral vein. Temperature was monitored in the cerebral hemispheres, the rectum and the vena cava. The extracellular lactate concentrations were measured by microdialysis in the frontal lobes.

RESULTS

Right brain temperature decreased to 33.6 +/- 2.0 degrees C from 37.7 +/- 1.1 degrees C 30 minutes after initiation of perfusion, while left brain and rectal temperatures were 34.3 +/- 1.7 and 34.1 +/- 1.3 degrees C, respectively. The cooling rate of the right cerebral hemisphere was 4.2 +/- 1.1 degrees C/ 30 minutes and advanced compared with the rectum (p<0.01), the left cerebral hemisphere and the vena cava (both p<0.05). There was no significant increase in the extracellular lactate concentrations in the cerebral hemispheres. Hemoglobin, hematocrit and cardiac function significantly changed during perfusion (p<0.05).

CONCLUSIONS

Brain hypothermia was rapidly and safely induced using an intra-arterial crystalloid infusion and an extracorporeal cooing-filtration system. With refinement and further assessment of metabolic and physiologic parameters, the method holds a potential for clinical utility.

Surgical management of patients with Marfan syndrome: evolution throughout the years

AIM

To evaluate the evolution of surgical management in a large population of patients with Marfan syndrome.

METHODS

This is a retrospective study of patients fulfilling the Ghent criteria for Marfan syndrome, who visited the Centre de référence national pour le syndrome de Marfan et apparentés and underwent a surgical event before or during follow-up in the centre.

RESULTS

One thousand and ninety-seven patients with Marfan syndrome, according to international criteria, came to the clinic between 1996 and 2010. Aortic surgery was performed in 249 patients (22.7%; 20 children and 229 adults), including the Bentall procedure in 140 patients (56%) and valve-sparing surgery in 88 patients (35%); a supracoronary graft was performed in 19 patients (7.6%), usually for aortic dissection. During the past 20 years, the predominant reason for aortic surgery has switched from aortic dissection to aortic dilatation, while age at surgery has tended to increase (from 32.4 ± 11.9 years to 35.2 ± 12.4 years; P=0.075). Mitral valve surgery was performed in 61 patients (5.6%; six children and 55 adults), including 37 valvuloplasties (60.6%) and 18 mitral valve replacements (29.5%). No significant difference was observed when comparing mitral valve surgery before and after 2000.

CONCLUSION

Surgery performed in patients with Marfan syndrome has switched from emergency surgery for aortic dissection to elective surgery for aortic dilatation; this is associated with surgery performed at an older age despite the indication for surgery having decreased from 60mm to 50mm. No significant evolution was observed for mitral valve surgery.

Emerging practice patterns and outcomes of percutaneous aortic balloon valvuloplasty in patients with severe aortic stenosis

A total of 33 patients with severe aortic stenosis undergoing percutaneous aortic balloon valvuloplasty (PABV) for bridging or palliative therapy were reviewed; the emerging treatment patterns for this procedure are described. Longitudinal data suggest that PABV provides a significant reduction in peak and mean aortic valve gradients with > 12-month survival for more than half of observed patients. This supports the current application of PABV, which is currently limited to palliative care and bridging therapy to more definitive forms of future treatment, including transcatheter aortic valve implantation.

[Operative treatment and diagnostics of Zenker diverticulum using modern endoscopic technique]

The authors present results of examination and treatment of 272 patients with Zenker diverticulums of different localization. Features and problems in fibroesophagoscopy in patients with Zenker diverticulum are discussed. Surgical interventions with endoscopic assistance were fulfilled in 37 patients with diverticulum. A new way of endoscopic management of Zenker diverticulum using preparation "Disport" and the method of endoscopic incision of cricofaringeal muscle are proposed. Good clinical results of the treatment were obtained.

Update on technologies for cardiac valvular replacement, transcatheter innovations, and reconstructive surgery

Since the 2006 Surgical Technology International monograph on valvular prostheses, there have been significant developmental and investigative advances, particularly for transcatheter implantation. Aortic bioprostheses and mechanical prostheses continue to incorporate design changes to optimize hemodynamics and prevent prosthesis-patient mismatch and to have a potential satisfactory influence on survival. There have been continual technological improvements striving to bring forward advances that improve the durability of bioprostheses and reduce the thrombogenicity of mechanical prostheses. There also has been a continuance to preserve biological tissue with glutaraldehyde, rather than clinically evaluate other cross-linking technologies, by controlling or retarding calcification with therapies to control phospholipids and residual aldehydes. The techniques of mitral valve reconstruction have now been well established, and annuloplasty rings have been designed for the potential of maintaining the anatomical and physiological characteristics of the mitral annulus. There has been limited advancement in the past four years for interventional annuloplasty, for remodeling of the length and shape of the dilated annulus, prevention of dilatation of the annulus, and support for the potentially fragile area after partial-leaflet resection. Currently, there continues to be emergence of catheter-based therapies, particularly for management of aortic stenosis but not mitral regurgitation. For management of selected populations with critical aortic stenosis, the techniques for aortic valve substitution have had further advancement for retrograde catheter techniques, as well as apical transventricular implantation. There has not been significant advancement during the past four years to address mitral regurgitation by experimental transcoronary sinus, stent-like devices and transventricular, edge-to-edge leaflet devices. The devices, descriptions, and pictorial images comprising this monograph have been limited to technologies that are considered to be predominant, at least for the immediate duration. The general purpose of the monograph is to serve as an educational document.

Balloon valvuloplasty in the treatment of congenital aortic valve stenosis--a retrospective multicenter survey of more than 1000 patients

BACKGROUND

The value of balloon valvuloplasty of the aortic valve in childhood is still under debate.

OBJECTIVE

To evaluate the results of the procedure in a retrospective multicenter survey of a large cohort over a long time interval.

METHODS

Retrospective analysis of 1004 patients with balloon valvuloplasty of the aortic valve performed between 9/1985 and 10/2006 at 20 centers in Germany, Austria and Switzerland. Amongst others, the following parameters were evaluated before and after the procedure as well as at the end of follow-up or before surgery: clinical status, left ventricular function, transaortic pressure gradient, degree of aortic regurgitation, freedom from re-intervention or surgery.

PATIENTS

Patients from 1 day to 18 years of age with aortic valve stenosis were divided into four groups: 334 newborns (1-28 days); 249 infants (29-365 days); 211 children (1-10 years), and 210 adolescents (10-18 years).

RESULTS

Median follow-up was 32 months (0 days to 17.5 years). After dilatation the pressure gradient decreased from 65 (± 24)mm Hg to 26 (± 16)mm Hg and remained stable during follow-up. The newborns were the most affected patients. Approximately 60% of them had clinical symptoms and impaired left ventricular function before intervention. Complication rate was 15% in newborns, 11% in infants and 6% in older children. Independently of age, 50% of all patients were free from surgery 10 years after intervention.

CONCLUSIONS

In this retrospective multicenter study, balloon valvuloplasty of the aortic valve has effectively postponed the need for surgery in infants, children and adolescents up to 18 years of age.

Paclitaxel eluting balloon: from bench to bedside

Despite the impressive progress of percutaneous treatment modalities, restenosis remains the major Achilles heel of interventional cardiology. Approximately 25% of the general population treated for coronary diseases with a bare-metal stent and about 10% of patients treated with a drug-eluting stent develop an overgrowth of vascular tissue and renarrowing inside the stent, or in-stent restenosis. These rates are even greater in diabetics and patients at higher risk of restenosis both for clinical presentation (patients in dialysis, low ejection fraction) or anatomical characteristics (ostial, bifurcation, long lesions). Non-stent based local drug delivery and particularly the use of paclitaxel eluting balloon (PEB) could be one promising strategy to reduce restenosis. This review will briefly explore the different characteristics of PEB devices currently present in the market and summarize the results obtained both in animal models and clinical practice, giving an indication of the potential field of application of this new technology.

Advances in paediatric interventional cardiology since 2000

Interventional paediatric and congenital cardiology is expanding at a rapid pace. Validated techniques (such as aortic or pulmonary valve dilatations and occlusion of persistent ductus arteriosus and atrial septal defects) are improving thanks to the use of smaller introducers and sheaths, low-profile balloons and novel devices. Moreover, catheter-based interventions have emerged as an attractive alternative to surgery in other fields: pulmonary valve replacement, balloon and stent implantation for native and recurrent coarctation, and percutaneous closure of ventricular septal defects. On the other hand, percutaneous interventions in the paediatric population may be limited by patient size or the anatomy of the defect. Hybrid approaches involving both cardiac interventionists and surgeons are being developed to overcome these limitations. Based on a better understanding of cardiac development, fetal cardiac interventions are being attempted in order to alter the history of severe obstructive lesions. Finally, some interventional procedures still carry a low success rate-for example, pulmonary vein stenosis, even with the use of conventional stents. Biodegradable stents and devices are being developed and may find an application in this setting as well as in others. The purpose of this review is to highlight the advances in paediatric interventional cardiology since the beginning of the third millennium.

Percutaneous valve procedures: Present and future

Percutaneous mitral commissurotomy and aortic valvuloplasty have been being performed since the mid-1980s. Balloon commissurotomy has been used in thousands of cases worldwide and it provides good short- and long-term results in a wide range of patients. It has virtually replaced surgical commissurotomy in the treatment of mitral stenosis. In contrast, percutaneous aortic valvuloplasty is almost abandoned worldwide due to its lack of efficacy and the risks involved. The new techniques of percutaneous valve intervention: aortic valve replacement and mitral valve repair are at an early stage: the first in-man applications of these fledgling techniques started in 2002. Preliminary series show that they are feasible; however, they need to be further evaluated in comparison with contemporary treatment to assess accurately how efficient they are and the risks involved. Currently potential applications concern high-risk patients, however, in the future, after thorough evaluation, this may be extended to others. Thus, percutaneous interventions already play an important role in treatment of valvular heart disease, a role that seems set for future expansion.

[Operation to remove tunnelled venous catheters in a dialysis unit. Is it possible to reverse the trend in their growing use?]

Introduction In an attempt to reduce unnecessary central venous catheters (CVC) dependence in prevalent population, a "CVC removal" programme was initiated in our unit. The objective was to diminish the number of CVC and to analyze the causes of their insertion and maintenance. On 09/01/07, 38 out of 173 prevalent patients on hemodialysis. Methods were CVC dependant (21.9%): 16 incident patients (42,1%) and 22 (57,8%) prevalent patients. All of them were re-evaluated for permanent vascular access utilization, included those previously rejected for surgery. Physical, psychical and vascular aspects regarding each patient were taken into consideration. The following variables were age, Body mass index, time on hemodialysis, Charlson analyzed comorbidity index, DM or vascular comorbidities and number of vascular accesses created prior to CVC placement. In those patients in whom AVF creation was feasible, the following were registered after 18 months of 1.Primary failure rate. 2. Related complications. 3. up follow Percentage of usable AVF or AVG. 4. Percentage of removed CVC. 5. Mortality and hospitalization. The decision of no realization of a new vascular access and? Results maintenance of TVC was performed in 21 patients (55.2%). In 9 of them was decision of the nephrologists and the family. In 11 patients was decision of vascular surgeon due to vascular bed exhaustion. A permanent VA was achieved in 17 patients (44.7%), 50% of them was incident patients and 45% prevalent patients. The primary failure rate was 0%. The TVC was withdrawn in 11/17 (64.7%). Only 4 patients remain without TVC after 18 months of follow-up: 5 patients died (4 with a AVF functioning and 1 VA closure due to steal syndrome) and in 8 patients was mandatory to reintroduce the TVC again. Immediate complications after the surgery were: 1 severe haematoma, 2 infections and 2 severe sequestrations. 3 patients required hospital admission following complications directly related to VA. Mean time of free of TVC was 5.2 months (range: 0.7- 14.3 months). The mortality was 29,4% (5/17) in the group of patients with a new VA and 9,5% (2/21) in the other group(RR 3,19; IC 95%: 0,68-13,98; p: 0,11). No significant differences were observed between patients who transitioned to a permanent vascular access and those who remained TVC dependant in regards to age, gender, BMI, time on dialysis, DM, comorbidity or number of previous VA, Transition from CVC use to hospitalizations or mortality. Conclusions permanent vascular access is possible in prevalent patients in dialysis. Improvement was achieved by a modest amount, and after a prolonged process with gravel complications, some of which proved severe. Need for CVC dependence is confirmed in a high percentage of prevalent patients on dialysis. Comorbidity might have influenced the results. The quality standard should be adequate to reality of current population on hemodialysis.

Radiofrequency cannula with active tip radio-opaque marker: image analysis for facet, gray ramus, and dorsal root ganglion techniques

BACKGROUND

Radiofrequency neurolysis is a common technique used in the treatment of chronic pain, particularly facet (zygapophyseal joint) arthralgia. A needle-like cannula is insulated except for the exposed active tip, which is positioned as parallel and adjacent as possible to the targeted nerve branch. Via an inserted probe connected to a radiofrequency generator, energy flowing from the tip of the cannula creates a heat lesion in the 80 - 85 degree Celsius range mostly about the length of the exposed active tip and in proportion to the diameter of the probe. The common active tip lengths used for neurolysis are 5mm or 10mm. The cannulae are FDA approved. The manufacturer advises physicians not to bend or otherwise modify a cannula prior to use. The cannulae are available straight or bent, sharp and blunt. The technique is guided under C-arm fluoroscopy. X-rays passing through the patient demonstrate in 2 dimensions the projected relative radio-opaque bony landmarks and the metallic cannula. Most currently available cannulae are uniform in their radio-opacity from tip to hub. The physician must make an educated guess as to the portion of the cannula that will be making the lesion in relationship to the bony landmark.

OBJECTIVE

A new radiofrequency cannula with a radio-opaque marker (ROC) delineates the proximal end of the active tip. The cannula was used in a phantom model. Images were reproduced with explanation of the potential advantage of the new device.

RESULT

The marker on the new cannula was visible and did help delineate the active tip as well as its orientation. It was also helpful in making sequential lesions at the same nerve using a "tip to tail" repositioning technique.

CONCLUSION

The ROC did represent an improvement over standard cannulae to optimize visualization of cannula and thus lesion placement using a phantom model. The applications described were only for conventional or "hot" RF.

Trends in silicone tubing

Silicone is the material of choice for many new applications. Those examined here include drug delivery and peristaltic pumps, pacemaker leads and tubing used in minimally invasive surgery and to deliver high pressure gases and liquids.

Percutaneous Mitral Valvuloplasty Versus Surgical Treatment in Mitral Stenosis With Severe Tricuspid Regurgitation

BACKGROUND

The persistence of significant tricuspid regurgitation (TR) after percutaneous mitral valvuloplasty (PMV) is known to be an independent predictor of adverse outcome in mitral stenosis (MS). However, it remains unclear whether mitral valve (MV) surgery combined with surgical correction of TR is the better treatment option than PMV in patients with severe MS and severe functional TR.

METHODS AND RESULTS

We included a total of 92 consecutive patients (18 men, age 49+/-13 years) with severe MS and severe functional TR, who were potential candidates for PMV from 1997 to 2005, and the exclusion criteria were defined as the presence of left atrial thrombi, mitral regurgitation > or = grade 3, echo score > 10, and left ventricular ejection fraction (EF) < 35%. PMV was performed on 48 patients (PMV group), and MV surgery combined with tricuspid valve (TV) repair was performed on 44 patients (TVP group). The clinical events were defined as death, repeat surgical or percutaneous intervention, and readmission because of heart failure. There were no significant differences between the 2 groups in terms of gender, baseline EF, and baseline severity of pulmonary hypertension, but patients in the TVP group were older and had a higher echo score and a higher incidence of atrial fibrillation than those in the PMV group. During follow-up of 57+/-35 months, 2 deaths occurred in the TVP group, and there were 2 deaths, 7 cases of heart failure requiring surgical intervention in the PMV group. The difference of event rates between the 2 groups showed borderline significance (P=0.05), but no difference in mortality was observed. The estimated actuarial 7-year event-free survival rate was 77+/-8% in the PMV group and 95+/-3% in the TVP group. Severe TR was improved to mild or absent TR in 43 (98%) patients in the TVP group, and this was significantly higher than in the PMV group (22/48, 46%; P<0.001). In the TVP group, the right ventricle (RV) size was significantly decreased in 18 (90%) patients among 20 patients with preoperative significant RV enlargement. On stepwise multivariate logistic regression analysis, TVP group and baseline sinus rhythm were independent predictors for improvement of TR (P<0.001).

CONCLUSIONS

TV repair combined with MV surgery was related to better clinical outcomes than PMV alone, and we recommend that this surgical option should be considered preferentially in severe MS with severe functional TR, especially if atrial fibrillation or enlarged RV is associated.

Cesarean Delivery in the Interventional Radiology Suite: A Novel Approach to Obstetric Hemostasis

BACKGROUND

The adjunctive use of interventional radiology procedures to minimize and control bleeding at the time of cesarean delivery has become increasingly common. These procedures require modern imaging equipment and supplies not available in traditional operating rooms.

METHODS

We describe three women who strongly desired continued reproductive function in clinical circumstances where postpartum hemorrhage and hysterectomy were likely.

RESULTS

Cesarean delivery was performed in the interventional radiology suite after selective uterine artery balloon placement and/or embolotherapy, which successfully minimized blood loss during delivery.

CONCLUSION

We propose that this novel surgical location is feasible, and may offer advantages in select patients.

Endovascular management of intracranial aneurysms: current experience and future advances

OBJECTIVE

The past 15 years have seen a revolution in the treatment of intracranial aneurysms. Endovascular technology has evolved rapidly since the Food and Drug Administration approval of Guglielmi detachable coils in 1995, which now allows successful treatment of most aneurysms. The authors provide a review of their 11-year experience at Jefferson Hospital for Neuroscience with endovascular embolization of intracranial aneurysms and discuss clinical trial outcomes and future directions of this treatment method.

METHODS

The authors reviewed the clinical and angiographic outcomes for 1307 patients undergoing endovascular treatment of intracranial aneurysms. Their analysis focuses on posterior circulation and middle cerebral artery aneurysms, as well as cases of stent-assisted coil embolization. They review their procedural protocol and patient selection criteria for endovascular management.

RESULTS

Several large clinical trials have demonstrated the safety and efficacy of endovascular treatment of intracranial aneurysms. The International Subarachnoid Aneurysm Trial provides Level I evidence demonstrating a significant reduction in disability or death with endovascular treatment compared with surgical clipping. The most common procedural complications include intraprocedural rupture and thromboembolic events; avoidance strategies are also discussed. Vasospasm after subarachnoid hemorrhage causes neurological morbidity and mortality and can be successfully managed by early recognition and interventional treatment with angioplasty, pharmacologic agents, or both.

CONCLUSION

Long-term studies evaluating experience with aneurysm coil embolization during the past decade indicate that this is a safe and durable treatment method. The introduction of stent-assist techniques has improved the management of wide-neck aneurysms. Future technology developments will likely improve the durability of endovascular treatment further by delivering bioactive agents that promote aneurysm thrombosis beyond the coil mass alone. It is clear that endovascular therapy of both ruptured and unruptured aneurysms is becoming a mainstay of practice in this patient population. Although not replacing open surgery, the continued improvements have allowed aneurysms that previously were amenable only to open clip ligation to be treated safely with durable long-term outcomes.

Recent steps toward a reconstructive endovascular solution for the orphaned, complex-neck aneurysm

OBJECTIVE

The purposes of this article are to summarize recent developments and concerns in endovascular aneurysm therapy leading to the adjunctive use of endoluminal devices, to review the published literature on stent-supported coil embolization of cerebral aneurysms, and to describe our experience with this technique in a limited subgroup of problematic complex aneurysms over a medium-term follow-up period.

METHODS

Between January 2003 and June 2004, 28 individuals among 157 patients with cerebral aneurysms we evaluated were identified as harboring aneurysms with exceptionally broad necks. Out of these 28 patients, 16 were treated with a combination of stents and detachable coils, preserving the parent artery. Recorded data included patient demographics, the clinical presentation, aneurysm location and characteristics, procedural details, and clinical and angiographic outcome.

RESULTS

Over an 18-month period, 16 patients with large cerebral aneurysms additionally characterized by neck sizes between 7 and 14 mm were treated, using combined coil embolization of the aneurysm with stent reconstruction of the aneurysm neck. Thirteen out of the 16 aneurysms were occluded at angiographic reevaluation between 11 and 24 months (mean angiographic follow-up, 17.5 mo). There were no treatment-related deaths or clinically evident neurological complications. Thirteen patients experienced excellent clinical outcomes, with good outcomes in two patients and a poor visual outcome in one patient (mean clinical follow-up, 29 mo). A single technical complication occurred, involving transient nonocclusive stent-associated thrombus, which was treated uneventfully with abciximab.

CONCLUSION

Stent-supported coil embolization of large, complex-neck cerebral aneurysms seems to provide superior medium-term anatomic reconstruction of the parent artery compared with historic series of aneurysms treated exclusively with endosaccular coils. In the near future, increasingly sophisticated endoluminal devices offering higher coverage of the neck defect will likely enable more definitive endovascular treatment of complex cerebral aneurysms and further expand our ability to manipulate the vascular biology of the parent artery.

The role of neuroendovascular therapy for the treatment of brain arteriovenous malformations

Neuroendovascular embolization represents a critical component of the multidisciplinary management of cerebral arteriovenous malformations. Safe and effective embolization may be performed only in the context of a well-designed, rational treatment plan that is fundamentally based on a clear understanding of the natural history of the lesion, as well as the cumulative risks of multimodality treatment. This article outlines the role of neuroendovascular embolization in arteriovenous malformation therapy with a specific emphasis on decision making in the context of formulating a treatment plan. The authors also provide a summary of the available embolic agents and their technical application, potential intraprocedural and periprocedural complications, and postprocedural management.

Therapy of brain arteriovenous malformations: multimodality treatment from a balanced standpoint

The three therapeutic modalities for arteriovenous malformation (AVM) treatment (surgery, embolization, and radiotherapy) developed in the past years with specific tools, each tool with its own qualities. Soon after the implementation of embolization for treatment of AVMs, this technique was used in combination with microsurgery; since the development of radiosurgery, treatment algorithms combining embolization with surgery and eventual subsequent radiosurgery, embolization with radiosurgery, or surgery with subsequent radiosurgery have been reported. These different combinations have been in use under the term multimodality treatment for many years, but the algorithms regarding the combination of tools, which tool has priority, and how the risk levels of each tool are assessed shows great variability among institutions. Centers with a surgical background see embolization as a technique to increase surgical feasibility and radiosurgery as a tool to complete subtotal AVM excision. Institutions with an endovascular background embolize AVMs with the aim of maximal occlusion rates and view surgery or radiosurgery as a technique to be used if the goal of total endovascular occlusion cannot be achieved. Radiosurgeons receive patients after incomplete embolization or surgical extirpation or a combination of both.

New Technologies in Peritoneal Dialysis: Figure 1

In recent years, there have been some interesting advances in the science and practice of peritoneal dialysis (PD). This review focuses on selected technological advances and the impact that these changes may have on this modality. New, so-called "biocompatible" fluids have more physiologic pH and reduced glucose degradation products. These new fluids may reduce the deleterious effects of chronic exposure to the peritoneal membrane. However, enthusiasm for these new fluids is outstripping rigorous evidence that they change patient outcome. Continuous-flow PD offers a way to increase dramatically small solute clearance. However, there are significant technological barriers to the implementation of this kind of dialysis. Furthermore, there is little evidence that augmented small solute clearance will improve survival in PD patients. Finally, new catheter insertion techniques provide perhaps the most practical advances in allowing successful commencement of this excellent home dialysis modality.

Brain aneurysms and arteriovenous malformations: advancements and emerging treatments in endovascular embolization

BACKGROUND AND PURPOSE

Brain aneurysms and vascular malformations can cause cerebral hemorrhages, with devastating consequences for the patients and their families. Since the development of microcatheters and materials used for endovascular embolization, we have witnessed a rapid advancement in the technology and in the number or patients treated with this approach. The aim of this review is to survey recent data relevant to new technologies and emerging treatment strategies in these areas.

SUMMARY OF REVIEW

Clinical trials assessing the safety and efficacy of coil embolization for cerebral aneurysms were based on the use of bare platinum, helical coils. Since then, endovascular operators have been testing and using new materials such as bioactive coils, expandable coils, and complex-shaped coils. Based on the data so far obtained, third and fourth generation coil designs are rapidly emerging and will be ready for clinical application in the near future. Balloon- and stent-assisted coil embolization is enabling the treatment of complex, large-neck aneurysms and the vascular reconstruction of lesions previously considered not treatable. New open- and closed-cell designs allow the navigation and deployment of stents in extremely tortuous vessels. With regards to the embolization of vascular malformations, it is possible to safely navigate microcatheters and microwires through very small arteries previously considered not accessible. In addition, embolization materials such as n-butyl cyanoacrylate and ethylene-vinyl alcohol copolymer are now routinely injected to safely reduce or obliterate large and complex arteriovenous malformations and fistulae.

CONCLUSIONS

Advancements in technology are rapidly improving the endovascular approach to the treatment of cerebral aneurysms and arteriovenous malformations.

Giant Cerebral Aneurysms: Endovascular Challenges

OBJECTIVE:

Giant (≥25 mm in diameter) cerebral aneurysms have a poor natural history, with high risks of subarachnoid hemorrhage or progressive disability or death caused by mass effect or stroke. Surgical treatment may be effective but carries a high burden of morbidity and mortality. Thus, attempts at endovascular solutions to these complex lesions have been developed to offer therapy at reduced risk.

METHODS:

The authors reviewed their clinical experience and the current body of literature concerning giant cerebral aneurysms and present their perspective on the current state of the art in endovascular therapy for these aneurysms. A variety of techniques are described that can be used in an attempt to provide a solution to the wide variety of clinical dilemmas associated with the management of these difficult lesions. Preprocedural planning and periprocedural considerations are discussed briefly. The use of intracranial balloons and stents are described in conjunction with the use of detachable platinum coils. The developing concept of using stents alone to treat aneurysms is discussed. Alternative methods of treating giant aneurysms are discussed.

RESULTS:

Current endovascular approaches, when properly selected and applied, can provide lower-risk therapies than conventional microsurgical approaches for patients harboring giant cerebral aneurysms. However, endovascular approaches do not, at present, provide results that are as durable as current surgical techniques for giant cerebral aneurysms.

CONCLUSION:

Treatment of giant cerebral aneurysms via endovascular therapeutics requires the interventionist to possess an extensive armamentarium. Meticulous preprocedure evaluation, patient selection, and execution of the treatment plan enable safe and effective management. Current therapies do not provide an ideal solution for every patient, so one must consider creative and evolving solutions to these difficult clinical challenges. The procedural morbidity of open surgery versus the decreased durability of current endovascular techniques must be assessed carefully.

Surgical Endovascular Neuroradiology in the 21st Century: What Lies Ahead?

FEW COULD HAVE imagined the tremendous growth of endovascular surgery over the past 40 years. Endovascular therapy has greatly enhanced the care of the patient in neurosurgery, spine surgery, and head and neck surgery. Progress in technology and techniques continue to push forward the boundaries of what is deemed “treatable,” assuming acceptable risk. This article will briefly review the current state of endovascular surgery and speculate about what its role will be in the near and far future. Endovascular therapy provides a minimally invasive approach to the central nervous system and other systems via natural and, at times, highly selective pathways. Maximizing the accessibility of these routes to highly specific regions of the central nervous system provides an elegant and minimalist approach to treating diseases of the central nervous system with almost no “footprints” of ever having accessed the region. In the future, safe, efficient and intelligent delivery systems that may enhance or alter the tissue's response may result in successful treatment of cerebrovascular diseases, as well as other diseases of the craniospinal axis. The growth of nanotechnology, metallurgy, synthetic polymers, imaging, and training will all combine to help grow the technology and the science that is surgical endovascular neuroradiology.

Anesthesia for Endovascular Neurosurgery

Endovascular neurosurgical procedures are complex, requiring significant planning, foresight, and coordination. The neuroanesthetist is an integral part of these procedures, organizing efforts of the technicians and nurses and responding to the needs of the neurointerventionalist. The purpose of this article is to review, in detail, the role of the neuroanesthetist in the endovascular operating room. An overview of all areas either partially or completely managed by the anesthetist is provided.

Giant Intracranial Aneurysms: Endovascular Challenges

THE TREATMENT OF giant aneurysms remains a formidable challenge for endovascular and surgical strategies. The use of endovascular techniques in a deconstructive (e.g., parent vessel occlusion) and reconstructive (e.g., stent coiling) methodology is reviewed. The results of endovascular coiling as a primary therapy for giant aneurysm occlusion have been disappointing. Hunterian strategies have had more success in published series, but recent developments in coil, glue, and stent technology show great promise in allowing parent vessel reconstruction as a primary endovascular target, with acceptable morbidity, mortality, and durability. A literature review of giant aneurysm endovascular treatment strategies was undertaken after 1994, when Guglielmi detachable coils were approved by the Food and Drug Administration. Where possible, follow-up, durability, and occlusion rates are also reviewed.

Challenges in the Endovascular Treatment of Giant Intracranial Aneurysms

OBJECTIVE:

Giant intracranial aneurysms present unique therapeutic intricacies. The purpose of this study was to evaluate the anatomic and hemodynamic characteristics of these lesions and the current endovascular and combined surgical and endovascular techniques available for their treatment.

METHODS:

A review of the literature and the personal experiences of the authors with endovascular treatment of giant aneurysms are presented. This review included anatomic and hemodynamic features and analysis of the diverse endovascular techniques that have been reported for the management of these aneurysms.

RESULTS:

Anatomic features that create particular challenges in the therapeutic approach of giant aneurysms include size, shape (saccular, fusiform, serpentine), neck dimensions, branch involvement, intraluminal thrombosis, and location. Hemodynamic characteristics that affect endovascular treatment are lateral or terminal aneurysm type of flow and embolic material placement (inflow versus outflow aneurysmal region). The current endovascular therapeutic approaches include parent artery occlusion, trapping, endosaccular embolization with or without adjunctive techniques such as balloon-assisted or stent placement, and combined surgical and endovascular approaches, mainly with surgical revascularization and endovascular occlusion.

CONCLUSION:

Although there are a wide variety of endovascular therapeutic options for the treatment of giant intracranial aneurysms, none of the current techniques is completely successful and free of complications in the management of these complex lesions. A detailed and individualized analysis of each case in conjunction with sufficient understanding of the anatomy and hemodynamics of a particular aneurysm should guide the therapeutic decision. Further research advances will assist in elucidating the factors predisposing to genesis, progression, and aggressive clinical manifestations of these giant lesions.

Endovascular Management of Cerebral Vasospasm

CEREBRAL VASOSPASM REMAINS a leading cause of death and disability in patients with ruptured cerebral aneurysms. The development of endovascular intervention in the past two decades has shown promising results in the treatment of vasospasm. Endovascular techniques that have been used in humans include intra-arterial infusion of vasorelaxants and direct mechanical dilation with transluminal balloon angioplasty. This article reviews the current indications and role of endovascular therapy in the management of cerebral vasospasm, its clinical significance, and potential future therapies.

Endovascular Training of Vascular Surgeons: Have We Made Progress?

The rapid evolution of catheter-based technologies during the last 5 years has created a critical need for development of effective resident level and postgraduate education programs in both open and endovascular techniques and associated cognitive and clinical skills. Currently, significant variability exists in endovascular training formats and in the number of endovascular procedures performed during the course of a graduate or postgraduate program. Little information on the quality of these programs exists and in the subsequent practice patterns of the trainees. This report reviews recommended credentialing requirements, training paradigms, and the growing experience of vascular surgical trainees since 2000.

Proceedings of the TCT: Balloon Aortic Valvuloplasty Appropriate for Elderly Valve Patients

Balloon aortic valvuloplasty (BAV) has been a highly successful therapy for children and young adults with aortic valve stenosis, resulting in both symptomatic improvement and durable increases in the aortic valve area. Despite enthusiasm for BAV in older adult patients with aortic valve stenosis in the mid-1980s, the therapy has had disappointing medium- and long-term outcomes. Survival of patients with aortic valve stenosis does not increase with BAV, and restenosis occurs in the vast majority of patients within 6-24 months after therapy. Despite these limitations, most patients are symptomatically improved for a year or more. BAV remains an effective palliative therapy for selected patients.

Materials for urinary catheters: a review of their history and development in the UK

The Foley catheter, introduced in the mid-1930s and originally manufactured from latex, is still the most commonly used device for the management of urinary incontinence (UI). Despite the passage of time, there are still problems associated with the use of these devices. It is currently estimated that the management and treatment of UI costs the UK National Health Service (NHS) in the order of 500 million pound per annum. Faced with the known demographic changes in the adult population these costs will continue to rise for the foreseeable future. This review examines the range of materials currently used to manufacture Foley catheters from both latex and silicone. It outlines the common problems associated with their clinical use-infection, encrustation and blockage. The main changes that have been made to the materials employed in response to these problems are analysed. In the first instance the use of controlled release glass and slow release polymers to introduce disinfectants and antibacterial agents is considered. Attempts to alter surface properties by using coatings based on silver, polytetrafluoroethylene (PTFE), hydrogels and silicone are then described. It can be seen that despite these approaches, problems remain with the design and materials currently used to manufacture catheters. The review concludes that changes to the materials currently used for the manufacture of commercially available catheters could potentially alleviate many of the existing problems. However, standards need to be developed in order to enable direct comparison of the mechanical and physical properties of existing and potential catheter designs to ensure their effective function in-service.

Percutaneous valve procedures: what is the future?

PURPOSE OF REVIEW

Since its introduction 27 years ago by Andreas Gruntzig, interventional cardiology has expanded its scope from coronary disease to peripheral, congenital, and also valve diseases.Percutaneous mitral commissurotomy and aortic valvuloplasty have been performed since the mid 1980s. Balloon commissurotomy has been used in tens of thousands of patients worldwide and provides good short- and long-term results in a wide range of patients. It has virtually replaced surgical commissurotomy in the management of mitral stenosis. On the other hand, percutaneous aortic valvuloplasty is almost abandoned worldwide due to its lack of efficacy and the risks involved.

RECENT FINDINGS

The new techniques of percutaneous valve intervention are aortic valve replacement, and mitral valve repair. Both are at an early stage since the first in-man applications only started in 2002. Preliminary series show that these techniques are feasible; however, they must be further evaluated in comparison with contemporary treatment to accurately assess efficacy and risks. Today potential applications concern high-risk patients, however, after thorough evaluation this may be extended to others in the future.

SUMMARY

Therefore, percutaneous interventions already play an important role in management of valvular heart disease, which is likely to grow in the future.

Changing pattern of care of boys with haemophilia in western European centres

Haemophilia management is not uniform among countries, even within western Europe, that have close economic, social and cultural relationship. The European Paediatric Network PedNet aims to share experiences in the field of the care of boys with haemophilia. In 1998, a PedNet survey has shown significant disparities in 20 centres from 16 countries, particularly as regards the implementation of prophylaxis regimen. This survey has been updated in 2003 to describe the current status of haemophilia management in 22 centres and the changing pattern of care of boys with severe haemophilia in western Europe. Regular, continuous long-term prophylaxis is provided in all PedNet centres, more than 50% and 80-100% of boys being treated this way in 20/22 and 15/22 centres respectively. Twenty of the 22 centres (91%) recommend continuous prophylaxis (primary or secondary A) for a new patient. The use of recombinant factor VIII concentrates was already widespread in 1998 and a further expansion of recombinant products has been observed over the last 5 years. Recombinant FVIII is now used exclusively in nine centres and for more than 80% of boys with haemophilia A in nine other centres. The use of recombinant and plasma derived FIX is more balanced: among 18 centres where boys with haemophilia B are treated, 14 use recombinant FIX, and nine administer it to a majority of patients. Other modifications of practice have been stressed in this survey, such as more targeted use of central venous devices in the youngest boys and more extensive characterisation of genetic mutations.

Catheter-related interventions to prevent peritonitis in peritoneal dialysis: a systematic review of randomized, controlled trials

As many as 15 to 50% of end-stage kidney disease patients are on peritoneal dialysis (PD), but peritonitis limits its more widespread use. Several PD catheter-related interventions (catheter designs, surgical insertion approaches, and connection methods) have been purported to reduce the risk of peritonitis in PD. The goal was to assess the trial evidence supporting their use. The Cochrane CENTRAL Registry, MEDLINE, EMBASE, and reference lists were searched for randomized trials of catheter types and related interventions in PD. Two reviewers extracted data on the rates of peritonitis and exit-site/tunnel infection, catheter removal/replacement, technique failure, and all-cause mortality. Analysis was by a random effects model, and results are expressed as relative risk and 95% confidence intervals. Thirty-seven eligible trials (2822 patients) were identified: eight of surgical strategies of catheter insertion, eight of straight versus coiled catheters, 10 of Y-set versus conventional spike systems, four of Y-set versus double-bag systems, and seven of other interventions. Despite the large total number of patients, few trials covered the same interventions, small numbers of patients were enrolled in each trial, and the methodologic quality was suboptimal. Y-set and twin-bag systems were superior to conventional spike systems (seven trials, 485 patients; relative risk, 0.64; 95% confidence intervals 0.53 to 0.77), and no other catheter-related intervention was demonstrated to prevent peritonitis in PD. This systematic review demonstrates that of all catheter-related interventions designed to prevent peritonitis in PD, only disconnect (twin-bag and Y-set) systems have been proved to be effective (compared with conventional spike systems). Despite the importance of PD as a renal replacement therapy modality and the large number of patients who receive it, it is still not known whether any particular PD catheter designs, implantation techniques, or modalities are effective, given the limitations of available trials.

[New approaches to gastric ph-metry]

The article is dedicated to three methods of gastric ph-metry: individualized ph-metry of two gastric zones, endoscopic ph-metry, and microprobe and reference electrode ph-metry.

Diffusion of new technology for the treatment of renovascular hypertension in the United States: Surgical revascularization versus catheter-based therapy, 1988-2001

BACKGROUND

Trends in the management of renovascular hypertension were evaluated by using a representative national database to determine whether a shift in treatment technology and outcomes has occurred.

METHODS

Clinical information regarding the treatment of renovascular hypertension in 5433 patients from 1988 to 2001 was derived from the Nationwide Inpatient Sample (NIS) database. Patients were classified into 3 groups: combined aortic and renal revascularization, isolated renal revascularization, and catheter-based procedures (angioplasty with or without stenting). Population-based trends were determined by using sampling weights for each year to estimate the total number of each intervention in the United States. Outcomes were compared using multivariate logistic regression analysis for risk-adjustment.

RESULTS

A 73% decrease in combined aortic and renal revascularizations ( P = .033) and a 56% decrease in isolated renal revascularizations ( P < .001) occurred during the study period. Catheter-based procedures have increased 173% from 0.4 to 1.1 procedures per 100,000 adults during this same time period ( P < .001). Predictors favoring catheter-based treatment were admission acuity, increasing age, nonwhite race, and high socioeconomic status. Predictors of mortality for all 3 treatment groups included increasing age, emergent admission, and nonwhite race.

CONCLUSIONS

A significant change in the management of patients with renovascular hypertension has occurred, with a shift towards less invasive catheter-based interventions. A better understanding of the diffusion of this technology in the treatment of individuals with renovascular hypertension will influence the training and distribution of future vascular specialists responsible for these patients.

Proton pump inhibitors and the time trends for esophageal dilation

AIM

Little is known about the impact of widespread proton pump inhibitor use on the need for dilation of esophageal strictures. To determine the time trends for upper endoscopy and stricture dilation before and after the availability of proton pump inhibitors.

METHODS

The computerized databases of two large community hospitals were analyzed. Annual data on dilation procedures (by all methods) and upper endoscopy were obtained and analyzed in quartiles from 1986 to 2001 to determine if the relative or absolute need for dilation changed following the introduction of proton pump inhibitors in the United States. The number of prescriptions for acid suppressive agents (H2 receptor antagonists and proton pump inhibitors) for the corresponding time period was obtained from the IMS health database.

RESULTS

A total of 57,496 upper GI endoscopies and 2,868 esophageal dilations were performed. The proportion of patients undergoing esophageal dilation increased from 4% in 1986-1989 to 6% in 1990-1993 (p < 0.001), remained unchanged (5.8%) in the period from 1994 to 1997 but declined significantly to 3.9% (p < 0.001) in the next quartile (1998-2001). Absolute numbers of dilation procedures declined significantly in the last quartile (1998-2001) and the proton pump inhibitor prescriptions in the United States increased markedly from 1995 onward.

CONCLUSIONS

The need for stricture dilation peaked in 1994 and has declined thereafter, corresponding to an increase in the use of proton pump inhibitors. The widespread use of proton pump inhibitors has not, however, abolished the need for esophageal dilation.

Management of patients with stroke and a patent foramen ovale

Observational studies have established a strong association between the presence of patent foramen ovale (PFO) and increased risk of ischemic stroke. The mechanism involved is presumed to be a paradoxical embolism from a venous thrombus that travels via the PFO to the systemic circulation. The best treatment modality to prevent recurrent stroke in patients with PFO remains undefined. There are four major choices: 1) medical therapy with anticoagulants, 2) medical therapy with antiplatelet agents, 3) surgical closure, and 4) percutaneous device closure. The Patent Foramen Ovale in Cryptogenic Stroke Study has demonstrated that antiplatelet and anticoagulant therapies are of equal benefit in preventing recurrent neurologic events in stroke patients with a PFO. Medical therapy should remain as the initial choice of secondary prophylactic therapy. PFO closure, either surgical or percutaneous, may further reduce event rates; however, this remains to be demonstrated because no randomized trial to date has compared PFO closure with medical therapy.