The association of clinical variables and filter design with carotid artery stenting thirty-day outcome.

OBJECTIVE: Patient and device selection are important for the success of carotid artery stenting (CAS). We hypothesize that distal protection filter (DPF) design characteristics that minimize blood flow resistance and maximize capture efficiency are associated with the absence of transient ischemic attack (TIA), stroke and neurologic-related death after 30 days. METHODS: Records from 208 patients were reviewed retrospectively. Filter design characteristics were quantified previously in our laboratory. The association between risk factors and design characteristics with 30-day outcome was quantified using univariate analysis. RESULTS: The 30-day all-cause stroke and death rate was 8.7% (asymptomatic: 7.7%, symptomatic: 10.6%). Five DPFs were used in the study: Accunet (41.3%), Angioguard (33.2%), FilterWire (24%), Emboshield (1%), and Spider (.5%). Diabetes (P = .04) and prior carotid endarterectomy (CEA, P = .03) were associated with adverse outcome. Prior stroke (P = .01) and prior CEA (P = .04) were significant for peri-procedural stroke. Design characteristics such as capture efficiency were associated with favorable outcomes. CONCLUSIONS: Patients with prior CEA or stroke are more likely to have unfavorable CAS outcomes after 30 days. Filters with high capture efficiency may yield the best clinical results. Analysis of the effect of design characteristics on CAS outcome should aid the design of future devices.

Current status in cervical carotid artery stent placement.

Based upon recent and old medical literature, with the exception of high surgical risk symptomatic patients, there remains much debate on how to manage extracranial carotid arterial disease, whether by surgical or endovascular intervention or by medical therapy alone. A review of the various global current carotid artery stent and endarterectomy registries and trials was performed incorporating more than 14,000 patients who have received carotid stents. There is substantial evidence supporting the benefit of carotid artery stenting (CAS) for the high anatomic risk population. Complication rates with symptomatic patients, including octogenarians, continue to show trend towards improvement as operators gain experience. The results are limited for standard risk carotid stenting for symptomatic patients though results with recent trials are pending but will probably show equivalence with endarterectomy. The asymptomatic patient population remains controversial: there is a small but reproducible benefit for revascularization. Long term (1-3 years) neurological results are now being reported for the major registries and trials. Analysis of target lesion revascularization, stroke and death rates of carotid stenting is comparable or better than rates for endarterectomy. Carotid artery stent placement has met the CMS targets 3% for MAE for asymptomatic patients and 6% for symptomatic patients with numerous registries and trials. CAS has also proven outcomes at 3 years with restenosis rates and stroke-free rates comparable or better than CEA. CAS provides an option for patients not suited for medical therapy and who were high-risk for CEA, especially for those symptomatic patients. It is still controversial with the role of stenting asymptomatic patients as well as for octogenarians. However, forthcoming trials will be helpful in providing more insight. Despite questionable studies and bad press, carotid stenting in the right hands with good patient selection is an excellent procedure. Finally, it is important to remember, carotid stenting is still in its early development and will only get better.

The expanding indications for virtual histology intravascular ultrasound for plaque analysis prior to carotid stenting.

Complications of carotid artery stenting (CAS), including stroke, remain relatively high when compared with carotid endarterectomy (CEA). Current selection criteria for patients undergoing CAS are based predominately on surgical risk related to other comorbidities. Little attention is given to the morphology of the atherosclerotic plaque, although studies have shown that extensive variability exists which confers certain risks for plaque vulnerability. Virtual Histology intravascular ultrasound (VH IVUS) offers a unique method of assessing plaque morphology prior to CAS. Herein, the authors review the concepts of atherosclerotic plaque morphology and discuss the background of VH IVUS and illustrate its use in the carotid system. With selection of the appropriate patient and the appropriate plaque, more favorable outcomes of CAS may be achieved which will solidify its place as a frontline treatment of carotid vascular disease.

Advances in balloon technology and reperfusion devices for peripheral circulation.

Major improvements in balloon and wire technology have been occurring for several years and, consequently, the approach to conventional angioplasty has been simplified. Results in isolated stenotic segments in renal circulation and within the iliac and superficial femoral vessels have generally been 95% technically successful, with 1-year patency rates of 80% in the superficial and renal sites and 90% in the iliac vessels. The procedure has been extended to include more distal vessels including the popliteal and tibial circulation as well as more complex lesions involving the mesenteric circulation and pre-Leriche syndromes with stenotic disease involving the infrarenal segment of the abdominal aorta. Successful results have also been achieved in stenotic atherosclerotic disease involving the subclavian artery and the associated subclavian steal syndromes. Preliminary results are also being reported in a few selected series of vertebral and carotid artery angioplasty. Totally occluded segments in the iliac and peripheral circulation had previously been ammenable only to surgical bypass procedures. A series of new recanalization devices are under investigational evaluation for reperfusing these totally obstructed segments. Although technical recanalization in segments as long as 20 cm can be accomplished in approximately 75% of these patients, long-term patency is totally dependent on popliteal-tibial outflow. For these reasons, diffuse disease and totally obstructive disease in the superficial femoral vessels can have recurrence rates as high as 45%, and reestablishing tibial outflow is equally as important as successfully recanalizing the totally obstructed superficial femoral vessels.

Percutaneous transluminal dilation of aortocoronary saphenous vein bypass grafts.

To evaluate the efficacy of percutaneous transluminal angioplasty as a possible alternative to repeated open heart surgery for symptomatic aortocoronary saphenous vein graft stenoses, the procedure was initiated at Shadyside Hospital in January 1978. Percutaneous transluminal angioplasty has been used in nine aortocoronary graft stenoses and 11 native coronary artery stenoses. Of the nine grafts, eight (88 percent) were successfully dilated, including three that had been totally closed as visualized by angiography. Of the 11 coronary dilations, only four (36 percent) resulted in improved flow. The more favorable results experienced with the graft dilations was thought to be due to the nature of the occlusive processes affecting these grafts. The fibrous intimal proliferative disease that is found in most grafts is easily compressible, while the nature of the disease in the coronary arteries is not so readily predictable. Better instrumentation and careful evaluation before and after angioplasty will improve the results and extend the indications for coronary artery and saphenous vein graft transluminal angioplasty.

Percutaneous transluminal angioplasty in the management of occlusive disease involving the coronary arteries and saphenous vein bypass grafts: preliminary results.

Since January, 1978, we have evaluated 18 patients in whom segmental occlusive disease of the aorta-coronary saphenous vein graft or the native coronary circulation was present. The significantly occluded vessels were restored to relatively normal circulation by means of percutaneous transluminal dilatation in 10 of these patients, with technical failures in seven patients and the occurrence of a thrombosis during the procedure in one other. Successful dilatation occurred in six of the seven patients with saphenous vein graft stenosis. Percutaneous transluminal angioplasty of the native coronary arteries in 11 patients resulted in five successful dilatations. All dilatation procedures are performed with the use of local anesthesia with an open-heart team standing by. In the event of technical failure or incipient thrombosis with developing infarction, the patient is transferred for immediate bypass. On the basis of these early results, we have developed guidelines of the indications for percutaneous transluminal dilatation of the coronary arteries and their saphenous vein grafts. The need for improved instrumentation to broaden these guidelines is discussed. Case histories of five patients are presented, and a summary table for all 18 patients is also provided. Certain inherent complications are discussed, but our preliminary results are encouraging, particularly with regard to stenoses of saphenous vein bypass grafts.

Performance of a hybrid central venous catheter utilized for both peripheral blood stem cell harvest and transplant support of patients undergoing autologous peripheral blood stem cell transplantation.

Patients undergoing autologous peripheral blood stem cell transplantation (PBSC) frequently require the sequential insertion of two central venous catheters, one for leukapheresis and one for transplant support. Hybrid catheters suitable for leukapheresis and long-term use have been increasingly used, but there is limited information regarding their performance and complication rate. The purpose of this study was to determine the performance of the Pheres-Flow hybrid catheter when utilized for both leukapheresis and transplant support, with particular emphasis on the incidence of infectious and occlusive complications. We prospectively analyzed the performance of 92 catheters in 82 consecutive patients who underwent autologous peripheral blood stem cell (PBSC) transplantation. Occlusion was the most frequent complication of this catheter with 29% of the patients experiencing difficulty drawing blood or infusing fluids. Infection was another frequent complication. Twenty-two percent of patients developed catheter-related bloodstream infections and 15 catheters had to be removed because of proven or suspected infection that did not respond to antibiotic therapy. Nevertheless, 77% of patients were able to complete leukapheresis and transplant support with only one catheter. We conclude that the utilization of the Pheres-Flow catheter for both leukapheresis and transplant support is feasible, but that new strategies need to be developed to decrease the incidence of occlusive and infectious complications of hybrid catheters.

Cardiovascular applications of digital subtraction angiography.

Continuing interest exists in the cardiovascular applications for digital subtraction angiography. The principal intravenous application is in the evaluation of left ventricular function and the quantitative parameters presently available for digital methods. Intraarterial applications include the ability to screen multiple vascular systems, including the coronary circulation and the carotid or peripheral vascular structures. Quantitative functions available are stenosis sizing, phase and amplitude analysis, and, finally, "road mapping" during cardiovascular interventional procedures. Major expansion of storage capacity, cine pulsing, and immediate access of online data represent a few of the major limitations of the procedure.

Initial clinical experience with colonic stent placement.

BACKGROUND: The purpose of this study is to review initial experience with a colonic stent as an alternative to colostomy in patients with colonic obstruction. METHODS: Ten patients diagnosed with acute colonic obstructions from both benign and malignant causes underwent stent placement. Self-expandable metallic stents were deployed using fluoroscopic guidance. Patients were followed up clinically until removal of the stent or death. RESULTS: Nine of the 10 patients who underwent colonic stent placement achieved clinical decompression within 6 hours. Six patients underwent standard mechanical bowel preparation and elective resection of obstructing lesions. The other 4 patients received stent placement for palliative purposes. Complications included 4 cases of migration and 1 death. Migrated stents in the rectum were easily retrieved and replaced using fluoroscopic techniques. There were no perforations. CONCLUSION: Placement of self-expandable metallic stents for acute colonic obstructions may allow patients to undergo elective surgical resection avoiding possible colostomy.

Current status in cervical carotid artery stent placement.

Aim of this paper is to provide background information and the latest developments and studies pertaining to carotid artery stent placement in the treatment of carotid artery occlusive disease. A review of current literature combined with personal experience in the field of carotid stenting is presented. Endovascular stent placement for carotid artery occlusive disease is evolving from its initial controversial position to that of an alternative treatment of extracranial carotid artery disease. The high technical success (98-99%) as well as the relatively few complications makes carotid stenting a substitute for carotid endarterectomy for symptomatic patients and especially those with high medical comorbidities. With the advent of distal embolic protection, the complication rates for carotid stenting have decreased by approximately 50% to 2-4% for most major centers. Hence, with improved technology, carotid stenting is becoming an option for asymptomatic patients, especially those with high surgical risk. Early results for patency and neurological follow-up have also been encouraging. When we first began performing carotid stenting in 1995, we used a mixture of peripheral and coronary techniques. As stent design, guide catheters and cerebral protection devices have become dedicated and sophisticated, the technical success, patency and complication rates have improved. Carotid stenting will increase in application in the future especially among high surgical-risk patients with symptomatic and asymptomatic carotid occlusive disease.

Extracranial carotid angioplasty and stenting. Initial results and short-term follow-up.

Carotid percutaneous transluminal angioplasty, with or without stent implantation, is becoming another therapeutic option for carotid revascularization. To evaluate the feasibility and effectiveness of the technique, from October of 1995 to March of 1997, we performed 24 percutaneous transluminal angioplasty procedures in 22 patients with severe extracranial carotid artery stenosis. Three common carotid and 21 internal carotid arteries were treated, and 19 procedures included stent implantation using nonarticulated PALMAZ stents (P154 and P204). Twelve patients were asymptomatic and 10 patients were symptomatic; 2 of the symptomatic patients had complete obstruction of the internal carotid artery that was successfully recanalized. Technical and angiographic success was achieved in 23 of 24 procedures, with the carotid artery obstruction diminishing from 85.6% +/- 8.5% to 5.7% +/- 3.2% (P < 0.001). Average stenosis length was 12.5 +/- 3.1 mm, and mean time of carotid occlusion during balloon inflation was 11.5 +/- 2.5 seconds. Three patients experienced transitory seizures during the procedure prior to dilation, 1 patient had a minor stroke with complete recovery within 72 hours, and 1 patient had a major stroke and died 45 days after the procedure. Clinical follow-up was achieved in all patients (mean, 10.5 +/- 7.2 months) and angiographic follow-up in 16 patients (mean, 6.3 +/- 1.2 months). The results obtained in this initial experience provide adequate support to continue further evaluation of this new therapeutic strategy.

New developments in endovascular interventions for extracranial carotid stenosis.

We provide an overview of recent developments in carotid interventional technique and equipment, including new stents and emboli protection devices. The newer self-expanding stents lessen the problem of external stent compression associated with balloon expandable stents, but precise deployment and the matching (by length) of stents to lesions remain problematic. We also discuss emerging pharmacologic strategies for cerebral protection in stroke. Multiple randomized clinical trials and multicenter registries are under way to compare percutaneous with surgical strategies for the treatment of carotid stenosis. These include the evaluation of emboli protection devices, and, to a lesser degree, intravenous glycoprotein IIb/IIIa antagonists. Other clinical trials are aimed towards refining the ability to stratify patients by risk, in order to identify the subsets that would benefit most from these complex and expensive procedures.

Scintigraphic detection of pulmonary hemorrhage using Tc-99m-sulfur colloid.

Pulmonary hemorrhage, whether in the form of hemoptysis or bleeding into the pleural space, may be a life threatening problem. While fiberoptic bronchoscopy and selective bronchial and intercostal angiography are the major diagnostic modalities, these techniques are not without risks. Two patients are described-one with massive hemoptysis from a bronchogenic carcinoma; another with pleural bleeding from a torn intercostal artery-in whom Tc-99m-sulfur colloid scintigraphy accurately located the source of hemorrhage. We conclude that Tc-99m-sulfur colloid scintigraphy may be a helpful noninvasive method to increase the sensitivity and specificity of fiberoptic bronchoscopy and bronchial angiography in patients with massive pulmonary bleeding.

Hemobilia detected by Tc-99m labeled red blood cells.

Tc-99m labeled red blood cells were successfully used to determine the site of hemorrhage in a 67-year-old man with hemobilia. A false hepatic artery aneurysm was confirmed at angiography and ultimately successfully embolized. The relative merits of using Tc-99m labeled red blood cells for detecting sources of upper gastrointestinal bleeding are discussed.

Acute rhabdomyolysis associated with cocaine intoxication: a case report.

Over thirty million Americans are estimated to have tried cocaine at least once and 5 million use it on a regular basis. Recent media attention to the widespread use of cocaine has revealed the growing life-threatening complications that accompany its use. The effects of cocaine on the cardiovascular, pulmonary and central nervous system have been well-described in medical literature, but the complications of acute renal failure secondary to cocaine-induced rhabdomyolysis only recently have been addressed. Presented in this article is a case involving cocaine-induced acute renal failure.