Extracranial revascularization therapy: Angioplasty and stenting

Opinion statement  Beginning with simple balloon angioplasty, minimally invasive revascularization techniques have progressed to the use of metallic stents for improved immediate and long-term results. Stent-supported angioplasty now offers a therapeutic option for those individuals ineligible for surgical revascularization of stenotic atherosclerotic lesions and who have failed maximal medical therapy. However, the clinical equivalence, or possibly even superiority, of angioplasty of the extracranial carotid and vertebral arteries in atheromatous occlusive disease over surgical revascularization has yet to be determined in ongoing randomized controlled trials. Additionally, endovascular techniques offer treatment for a variety of nonatherosclerotic disease affecting the extracranial arteries, such as inflammatory, radiation-induced, and postsurgical strictures; acute intimal dissection; traumatic and spontaneous arteriovenous fistulas; and aneurysms or pseudoaneurysms. For certain disease entities at high risk for surgical complications, endovascular procedures have gained preference as the therapeutic modality of choice, yet lacking controlled trials providing evidence for noninferiority against surgical approach. Continued innovation and refinement of endovascular technology and techniques will further improve technical success, reduce procedurerelated morbidity, and broaden the endovascular therapeutic spectrum for extracranial and intracranial cerebrovascular disease.     

Carotid stent placement for extracranial carotid artery disease: current state of the art.

Percutaneous revascularization techniques have dramatically altered traditional approaches to the management of both coronary and peripheral vascular disease. Their major advantage is that they are less invasive than conventional surgical procedures, offering revascularization without the risk of general anesthesia and with lesser procedural morbidity and mortality, shorter hospital stay, and lower cost. In patients with comorbidities that increase their risk of surgical complications, percutaneous revascularization techniques are the procedures of choice. The Achilles heel of balloon angioplasty, the higher risk of lesion recurrence, restenosis, has been markedly reduced with the use of endovascular stents. Over the past 20 years, percutaneous angioplasty and stenting have become accepted alternatives to surgical revascularization of aortoiliac, renal, femoropopliteal, subclavian, brachiocephalic, and dialysis access lesions. The most recent application of percutaneous intervention has been to explore its clinical utility and safety for stroke prevention in stenotic extracranial carotid arteries. Cathet. Cardiovasc. Intervent. 51:339-346, 2000.     

Carotid endarterectomy versus angioplasty/stenting for carotid stenosis

Carotid occlusive disease remains an important cause of ischemic stroke. The results of large, randomized clinical trials have established the benefit of surgical revascularization in selected patients with symptomatic or asymptomatic carotid stenosis. The introduction of balloon angioplasty and stenting of the extracranial carotid artery as a potential alternative to surgery has been received with enthusiasm by patients and physicians alike. Whether or not this enthusiasm is fully justified has yet to be determined. This article reviews published data regarding the safety and clinical efficacy of carotid angioplasty and stenting. Particular focus is directed towards results from recently completed and ongoing prospective comparative trials of endarterectomy and carotid angioplasty and stenting.     

Renal artery stenosis

Among the indications for renal artery revascularization, either surgical or endovascular, in patients with renal artery stenosis are poorly controlled hypertension, ischemic nephropathy (preservation of renal function), or recurrent episodes of "flash" pulmonary edema and congestive heart failure. Pharmacologic treatment is the first-line therapy to control blood pressure. If the disease is unilateral, the blood pressure regimen should include an angiotensin-converting enzyme inhibitor. Guidelines published in the Sixth Report of the Joint National Committee on the Prevention, Detection, Evaluation, and Treatment of high blood pressure should be followed. Revascularization is recommended if patients have at least 75% stenosis of one or both renal arteries, combined with resistant or poorly controlled hypertension; recurrent flash pulmonary edema; dialysis-dependent renal failure resulting from renal artery stenosis; chronic renal insufficiency and bilateral renal artery stenosis; or renal artery stenosis to a solitary functioning kidney. To treat fibromuscular disease of the renal arteries, percutaneous transluminal angioplasty is the revascularization procedure of choice. Ex vivo surgical repair of the renal artery may be required if there is significant branch renal artery stenosis. To treat atherosclerotic renal artery stenosis, the revascularization procedure of choice is percutaneous transluminal angioplasty and stent implantation, especially if there is concomitant ostial or proximal renal artery disease. Surgical revascularization is performed if concomitant aortic surgery is required, such as for abdominal aortic aneurysm.     

Aktuelle Strategien in der Therapie der Nierenarterienstenose

Severe renal artery stenosis may cause renovascular hypertension; in case of bilateral narrowing or in a stenotic solitary kidney, renal insufficiency (ischemic kidney disease) or rarely pulmonary flush edema may occur. Renal artery stenosis may be treated by revascularization, using either percutaneous (balloon angioplasty, stenting) or less common open surgical procedures, both with excellent primary patency rates. However, randomized trials of renal artery angioplasty or stenting have failed to demonstrate a longer-term benefit with regard to blood pressure control and renal function over medical management alone (except for fibromuscular disease). Furthermore, endovascular procedures are associated with substantial risks. It has not yet been demonstrated that renal revascularization leads to a prolongation of event-free survival. Careful patient selection is essential to maximize the potential benefit.     

Optimal treatment of carotid artery disease

Extracranial carotid artery disease accounts for approximately 25% of ischemic strokes. Although carotid endarterectomy (CEA) is the established gold standard for carotid revascularization, carotid artery angioplasty and stenting (CAS) is continually developing into a safer and more efficacious method of stroke prevention. Embolic protection, improving stent designs, and ever-increasing surgeon experience are propelling CAS towards equipoise with and possible superiority to CEA. One multicenter randomized trial and several nonrandomized registries have successfully established CAS as an accepted treatment for high-risk patients. Clinicians must strive to perform well-designed clinical trials that will continue to aid understanding and improve application of both endovascular and open techniques for extracranial carotid revascularization. We review the data published to date regarding the indications for and recent developments in the use of CAS.     

Peripheral interventions and antiplatelet therapy: Role in current practice

Peripheral arterial disease(PAD) is a common disorder associated with a high risk of cardiovascular mortality and continues to be under-recognized. The major risk factors for PAD are similar to those for coronary and cerebrovascular disease. Management includes exercise program, pharmacologic therapy and revascularization including endovascular and surgical approach. The optimal revascularization strategy, endovascular or surgical intervention, is often debated due to the paucity of head to head randomized controlled studies. Despite significant advances in endovascular interventions resulting in increased utilization over surgical bypass, significant challenges still remain. Platelet activation and aggregation after percutaneous transluminal angioplasty of atherosclerotic arteries are important risk factors for re-occlusion/restenosis and life-threatening thrombosis following endovascular procedures. Antiplatelet agents are commonly prescribed to reduce the risk of myocardial infarction, stroke and death from cardiovascular causes in patients with PAD. Despite an abundance of data demonstrating efficacy of antiplatelet therapy in coronary artery disease and cerebrovascular disease, there is a paucity of clinical information, clinical guidelines and randomized controlled studies in the PAD population. Hence, data on antiplatelet therapy in coronary interventions is frequently extrapolated to peripheral interventions. The aim of this review article is to elucidate the current data on revascularization and the role and duration of antiplatelet and anticoagulant therapy in re-vascularized lower limb PAD patients.     

Update on Lower Extremity Endovascular Interventions

In the past decade there have been major strides in the development of devices and techniques for nonsurgical lower extremity revascularization. These advances have broadened indications for endovascular therapies and expanded the treatment options for patients with peripheral vascular disease. A variety of new laser-etched steel and nitinol stent designs now complement balloon angioplasty. In the iliac segment, stenting has replaced balloon angioplasty as the first-line therapy for treatment of symptomatic occlusive disease. Stenting results in superior acute procedural success and long-term clinical efficacy compared to balloon angioplasty and is a "less invasive" alternative to surgical reconstruction. Endoluminal stent grafts offer promise in the treatment of high-risk patients with abdominal aortic aneurysms. New strategies are being developed to address the diverse nature of the superficial femoral artery (SFA) and infrapopliteal disease where balloon angioplasty, stenting, and stent graft strategies have proven unsatisfactory for treatment of diffuse disease and long occlusions. The next millennium will see the use of "therapeutic angiogenesis," the intravascular and intramuscular administration of DNA fragments or proteins, to stimulate new vessel growth in patients not amenable to conventional surgical or endovascular therapies. Brachytherapy, the intravascular delivery of a retrievable ionizing radiation source, represents an exciting development that offers the potential of reducing restenosis in the SFA.     

Interventional treatment of extracranial carotid stenoses: current status, requirements and indications

Interventional treatment of extracranial carotid stenoses: current status, requirements and indications Around 30000 strokes per year in Germany are caused by extracranial obstructions of the carotid arteries. Besides the well established surgical endatherectomy, which has been proven to be superior to medical treatment alone in randomized multicenter trials, percutaneous treatment by balloon angioplasty and stent placement is increasingly performed. This consensus paper summarizes the present status of scientific studies and controlled treatment registries of carotid angioplasty and stenting and yields to recommendations regarding its performance and indication. A Medline search was done until August 2005 including all randomized comparative studies with clinical endpoints and all controlled registries with more than 500 patients included. Both completed randomized trials comparing angioplasty and stenting with surgery (CAVATAS and SAPPHIRE) did not show a significant difference with respect to stroke and death within 30 days. The incidence of this combined endpoint was between 3.3 and 6.9% in large multicenter registries. Thus, the current endovascular treatment results in a perlinterventional complication rate comparable to that which is commonly accepted for vascular surgery. A systematic preferably external quality monitoring as well as interdisciplinary cooperation most importantly with neurologists is recomendedfor all interventionalists. Based on available clinical data, this consensus paper defines recommendation classes I or II with a level of evidence B or C depending on symptoms, operative risk status of the patient and severity of the underlying stenosis.     

Role for endovascular therapy in chronic mesenteric ischemia

Chronic mesenteric ischemia is a rare condition that is caused by stenosis or occlusion of the mesenteric arteries and usually manifests as abdominal pain. While surgical revascularization has been the standard treatment for symptomatic patients, recent advances in interventional devices and techniques have made endovascular treatment feasible and effective. Percutaneous transluminal angioplasty with stent placement is now recognized as a minimally invasive means of obtaining good long-term results with an acceptable recurrence rate; consequently, the technique is suggested for the primary treatment of chronic mesenteric ischemia. The present article discusses the indications and principles of endovascular treatment, and reviews the literature, with emphasis on short- and long-term outcomes, particularly morbidity and mortality rates.     

Successful Aspiration and Rheolytic Thrombectomy of a Renal Artery Infarct and Review of the Current Literature

The use of revascularization techniques including angioplasty, thrombectomy, and stenting in the coronary, cerebral, and peripheral arteries has revolutionized the entire field of endovascular therapeutics. In renal thromboembolism, the classic treatment has been anticoagulation with possible thrombolysis and surgical thrombectomy. The role of endovascular therapy in renal thromboembolism remains controversial. There are a few anecdotal reports about the use of aspiration and rheolytic thrombectomy in the renal arteries. We present a case of acute renal infarction resulting from systemic embolism secondary to atrial fibrillation. This was treated with revascularization, including aspiration and rheolytic thrombectomy, with excellent results.     

Endovascular treatment for vertebrobasilar insufficiency

Opinion statement Endovascular management of supra-aortic atherosclerotic vascular disease is becoming relatively common in the innominate, subclavian, and carotid arteries. However, revascularization of vertebral artery disease is an infrequently used treatment option due to several reasons: 1) stroke etiology and prevention is generally considered with respect to carotid disease as posterior circulation ischemia is poorly defined; 2) the limited success and excessive morbidity have made surgery an unattractive option for vertebral artery revascularization; 3) routine screening for posterior circulation disease as an etiology for stroke is rarely performed; and 4) endovascular treatment of vertebrobasilar insufficiency is not routinely performed in peripheral interventional programs. Randomized data comparing medical therapy, endovascular treatment, or surgical treatment do not exist. Due to infrequent identification of vertebral artery disease as the etiology of posterior circulation symptomatology, randomized comparisons will be difficult to obtain. Balloon angioplasty alone, provisional stenting, or primary stent placement for the treatment of vertebral artery stenosis is associated with low restenosis rates and high success rates. The available literature demonstrates angioplasty with stent placement of posterior circulation, symptomatic, vertebrobasilar atherosclerotic disease is a safe and effective approach that avoids the morbidity associated with major surgery. We believe primary stent placement is the treatment of choice for vertebral artery revascularization due to the high technical success rate, low incidence of morbidity and mortality, and long-term durability.     

Vertebral Insufficiency: When to Intervene and How?

Percutaneous transluminal angioplasty and stenting of supra-aortic atherosclerotic vascular obstructions is becoming relatively common in the innominate, subclavian, and carotid arteries. However, percutaneous revascularization of atherosclerotic vertebral artery disease is an infrequently used treatment option. We believe that angioplasty and stent placement of posterior circulation, symptomatic, vertebrobasilar atherosclerotic disease is a safe and effective approach which avoids the morbidity associated with major surgery. Surgical revascularization of symptomatic vertebral artery stenosis is rarely performed due to limited surgical success and increased surgical morbidity. Balloon angioplasty alone or combined with stenting is associated with high success rates and low restenosis rates, although there is a scarcity of published peer-reviewed data. Series of endovascular stent placement in vertebral arteries alone for the treatment of posterior circulation ischemia is unpublished.Typical posterior circulation (vertebrobasilar) ischemic symptoms include diplopia, dizziness, drop attack, gait disturbance, or a transient ischemic attack. Initial treatment is with anticoagulation or antiplatelet therapy. We believe primary stent placement is the treatment of choice for vertebral artery revascularization due to the high technical success rate, low incidence of morbidity and mortality, and long-term durability.     

Update on Cutting Balloon Angioplasty

Cutting balloon (CB) is a unique balloon catheter with 3 or 4 metal blades on its surface making controlled endovascular surgical incisions that show promise of causing less vessel wall injury and less intimai proliferation. Multicenter randomized trials have revealed that CB angioplasty with multiple inflations achieved better lumen enlargement than single inflation and reduced coronary dissection more than plain old balloon angioplasty (POBA). Follow-up results showed CB angioplasty had a smaller late loss and loss index, resulting in lessened restenosis and target lesion revascularization rates. The main indication of CB angioplasty is basically a noncalcified lesion with concentric plaque; however, it could be applied effectively to some lesions unsuitable for POBA including in-stent restenosis, small vessel, long diffuse lesion, or ostial lesion. Additional evaluation would be necessary to determine the role of CB angioplasty in the stent era.     

Clinical trials of coronary revascularization for chronic stable angina: medical treatment versus coronary revascularization

For patients with chronic stable angina, several randomized trials have been performed comparing medical management with surgery, medical management with angioplasty, and angioplasty with surgery. Data from the medical versus revascularization trials (either surgery or angioplasty) support the following contentions: For patients with multivessel disease, particularly involving the proximal left anterior descending coronary artery, survival is superior to surgical treatment. Symptom relief with either type of revascularization is superior to medical management. The subsequent rate of myocardial infarction is not affected by the initial treatment strategy, whether medical, angioplasty, or surgery. In individual patients the potential benefits of any revascularization strategy must be weighed against its initial risks. Further study is needed, particularly with multifaceted pharmacologic therapy and with updated angioplasty techniques, to evaluate relative survival benefits in these patients. The studies supporting these conclusions are highlighted in this paper.     

Percutaneous transluminal coronary angioplasty: the second decade

Over the last decade, percutaneous transluminal coronary angioplasty has become a major therapeutic technique of myocardial revascularization. Advances in catheter design and operator experience have made angioplasty a viable alternative for many patients with both single- and multivessel disease who would otherwise require bypass surgery. Acute closure and restenosis remain the 2 principal limitations of angioplasty. Means of controlling these problems, including intracoronary stenting and antiplatelet and thrombolytic agents, are now being studied. Furthermore, controlled prospective randomized trials are underway to assess the value of angioplasty compared with coronary bypass surgery in the treatment of multivessel disease. These trials will help to establish the limits of coronary angioplasty and its relative advantages in terms of therapeutic results and costs.     

Therapeutic approach to the unilateral occlusive iliac artery disease. Preliminary results

BACKGROUND: The different therapeutic approaches to unilateral occlusive iliac artery disease are analyzed. METHODS: In the period from September 1999 to September 2001, a total of 43 patients (38 males and 5 females) has been treated for unilateral iliac artery occlusive disease. Thirty-four cases (79%) underwent an endovascular procedure, and the remaining 9 cases (21%) had a surgical intervention. Endovascular techniques included 11 cases of percutaneous transluminal angioplasty (PTA) of common iliac artery (25.6% of whole series), 5 PTA of external iliac artery (11.6%), 8 PTA+stenting of common iliac artery (18.6%) and 10 PTA+stenting of external iliac artery (23.2%). In 9 cases a surgical revascularization was performed: 6 patients underwent a femoro-femoral cross-over bypass (14%); 2 cases were treated with aorto-bifemoral reconstruction (4.7%) and one patient was operated with ilio-femoral graft (2.3 %). RESULTS: The analysis of the follow-up of our series showed, in the group of 34 patients treated with endovascular procedures, successful results were obtained in 79.4% (27 cases); in the 9 patients operated with surgical revascularization the success rate was 88.9% (8 cases ); failure rate was 20.6% for endovascular procedures and 11.1% for surgical interventions. CONCLUSIONS: The conclusion is drawn that endovascular approach (PTA, stenting) is usually the procedure of choice in the treatment of unilateral well localised lesions of the iliac artery. Conventional surgical intervention is effective for revascularizing an extensive involvement of the iliac segment or in case of bilateral disease.     

Wireless laser-assisted angioplasty of the superficial femoral artery in patients with critical limb ischemia who have failed conventional percutaneous revascularization.

Percutaneous revascularization has become an effective treatment for patients suffering from chronic critical limb ischemia (CLI) due to chronic atherosclerotic obstructions, including total occlusions. Unlike other vascular beds, total chronic occlusions of the femoropopliteal arteries are frequently found in patients with severe claudication or CLI. As a consequence, patients with long chronic total occlusions of the femoropopliteal arteries are generally not considered optimal candidates for percutaneous revascularization and are frequently referred for surgical revascularization. In the present study, we sought to evaluate the feasibility, safety, and outcome of a modified wireless laser ablation technique to recanalize total occlusions in patients with CLI who had failed conventional percutaneous techniques for limb salvage. Procedural success, complications, actuarial freedom of limb loss, and surgical revascularization were evaluated in 25 patients after a mean follow-up of 13 +/- 8 months. Procedural success was achieved in 21 patients (84%). Actuarial freedom from surgical revascularization or limb loss was 72%. There was one vascular perforation. No deaths or distal embolization occurred. Three patients (12%) required limb amputation during follow-up, whereas four patients (16%) had surgical revascularization in the presence of feasible vascular targets. Limb salvage was achieved in 88% of patients when laser recanalization was combined with surgical revascularization. These results suggest that the use of laser ablation is safe and facilitates angioplasty and stenting in patients with CLI that failed conventional endovascular revascularization. This technique might prevent limb loss in patients with CLI due to femoropopliteal total occlusions, particularly in patients with unsuitable anatomy for surgical revascularization.     

Koronarchirurgie bei Diabetes mellitus

Patients with coronary artery disease (CAD) and diabetes mellitus have an increased risk of mortality when undergoing either interventional or surgical revascularization. However, the rate of necessary reinterventions is significantly lower after surgical revascularization than after percutaneous transluminal coronary angioplasty (PTCA). As yet, no results of long-term follow-up after stent implantation are available. The risk for a patient with diabetes mellitus and CAD of dying of myocardial infarction after a bypass operation is significantly lower than after PTCA. Bypass operation with sternotomy in patients with diabetes mellitus carries, however, an increased risk of postoperative mediastinitis, especially when both internal thoracic arteries are used for "totally arterial" revascularization. For this reason the internal thoracic artery should be used only unilaterally in surgical revascularization in these patients. Preoperative and postoperative stabilization of the blood sugar level is very important. Sclerosis of the vessels in close proximity to the heart (ascending aorta, carotid arteries) must be clarified preoperatively. The operation should be carried out particularly carefully, with the wound area kept as small as possible. Reexploration should definitely be avoided. If these guidelines are followed, surgical revascularization in patients with CAD and diabetes mellitus can achieve very good results.     

Endovascular therapies for vascular disease

Endovascular techniques including angioplasty, stenting, and endoluminal stent grafts represent important therapeutic options for the treatment of vascular disease. Technologic advances have allowed for the treatment of aneurysmal disease as well as extra-cranial carotid disease that previously required surgical methods. The success of various endovascular therapies varies based on anatomic location and extent of disease. The clinical results in different arterial segments are increasingly recognized in the published literature. The aortoiliac arterial bed appears to respond most favorably, with less favorable results observed in the infra-inguinal and infrapopliteal locations. There is increasing evidence that stent-supported carotid angioplasty using cerebral protection will play an important future role in the treatment of carotid artery stenosis. Less invasive techniques to treat abdominal aortic aneurysms with endoluminal stent grafts have dramatically changed the available therapeutic options. Improved devices and delivery systems will likely increase the number of patients who can be successfully treated in this manner. The evolution of endovascular therapies will continue to change the way we treat vascular disease.