Interventional Neurovascular Techniques Research Articles

POTENTIAL ROLE OF INTERVENTIONAL NEUROVASCULAR THERAPY FOR CEREBROVASCULAR DISEASE

BACKGROUND- Recent advances in intracranial vascular catheterization along with new microballoon technology have led to an increasing interest in using interventional techniques to treat cerebrovascular disease. REVIEW SUMMARY- Interventional techniques including percutaneous transluminal angioplasty and intra-arterial thrombolysis have shown great promise in stroke prevention and treatment. Multicenter clinical trials are in progress. CONCLUSIONS- Interventional neurovascular techniques may prevent strokes and improve stroke recovery.

Interventional neurovascular techniques in the treatment of stroke--state-of-the-art therapy.

Interventional neurovascular techniques for the treatment of patients presenting with symptoms of acute or impending stroke, are now being utilized with increasing frequency in three major areas. (i) For patients presenting with cerebrovascular ischaemic symptoms due to haemodynamically significant stenosis from atherosclerosis, vasculitis, intimal hyperplasia, and dissection, cerebral percutaneous transluminal angioplasty has been shown to be beneficial for both extracranial and intracranial disease. (ii) Patients with acute, embolic occlusion of the internal carotid, middle cerebral, distal vertebral, and basilar arteries have been successfully treated by placement of microcatheters directly into the thrombus with successful thrombolysis, recanalization, and reperfusion to the distal ischemic brain. (iii) Acute arterial vasospasm secondary to subarachnoid haemorrhage is now being managed by balloon angioplasty in those instances where conventional medical therapy has failed. These techniques are altering our current management and broadening the therapeutic alternatives for patients who present with acute cerebrovascular insufficiency and stroke in evolution. As wider experience is gained in these techniques, the clinical indications for their use will also broaden.

Stroke therapy — time for a clinical breakthrough

Abstract. Attempts to limit brain infarct size and improve clinical outcome in patients with acute ischaemic stroke have focused on the restoration of blood flow and neuroprotection. Haemodilution to improve blood flow in the low‐flow zone (penumbra) surrounding the core of the infarct has not been successful in clinical trials. No consistent effect of prostacyclin has been documented. In contrast, beneficial effects of thrombolytic agents (streptokinase, urokinase or t‐PA) have been reported in animal models of stroke and in small series of patients with ischaemic stroke. There is a substantial risk of intracerebral bleeding that increases with delay from onset of symptoms to start of treatment. Large‐scale, placebo‐controlled trials of intravenous rt‐PA and streptokinase are ongoing. Interventional neurovascular techniques have been successfully applied in patients with acute embolic occlusion of extracranial or intracranial arteries, and these procedures are now ready for randomized trials.Amongst neuroprotective agents, calcium‐channel blockers have been most extensively studied in clinical trials, but no convincing benefits have been shown. Scavengers of free radicals and inhibitors of presynaptic glutamate release and glutamate‐receptor blockers reduce brain infarct size in laboratory animals and are now being investigated in clinical trials.To fully exploit, in routine clinical practice, a breakthrough in reperfusion and/or neuroprotection therapy, a drastic reorganization of the management of stroke patients before and immediately after arrival to hospital will be needed.

Interventional neurovascular techniques for cerebral revascularization in the treatment of stroke.

Recent advances in interventional neurovascular radiology have altered the management of cerebrovascular diseases by providing alternative treatments in three areas. (1) Cerebral percutaneous transluminal angioplasty is being used more often as an alternative to surgical endarterectomy or bypass grafting for patients with high-grade vascular stenosis of the innominate, subclavian, carotid, vertebral, and intracranial blood vessels. To date, the success rate has been greater than 90%, with less than 10% morbidity. (2) Transluminal angioplasty and local infusion of antispasmodic drugs are being used to treat patients with severe angiographic vasospasm unresponsive to conventional medical therapy. Intracranial arterial vasospasm due to subarachnoid hemorrhage has remained a leading cause of delayed morbidity and mortality. Neurologic improvement, defined as improvement in the Hunt and Hess neurologic grading scale, has been shown in 60-80% of the patients so treated. (3) Local intraarterial fibrinolysis has been beneficial for patients with acute thromboembolic occlusion in both intracranial arteries and the cerebral dural sinuses. Preliminary studies indicate that early revascularization is associated with improved neurologic outcome. This review delineates the current state of the art in interventional neurovascular techniques for treating patients with stroke in evolution and patients with signs and symptoms of impending stroke due to vascular stenosis or occlusion. These techniques for cerebral revascularization are under investigation as potential life-saving therapy when conventional medical or surgical treatment has failed. As more experience is gained, the results of controlled clinical trials become available, and technical improvements evolve, these procedures will decrease the morbidity and mortality associated with strokes.

Intracranial Aneurysms: Evolution and Future Role of Endovascular Techniques

Treatment of patients with an intracranial aneurysm by interventional neurovascular techniques has made tremendous advances over the past decade. Innovative occlusion devices have included detachable latex and silicone balloons, liquid polymers, intravascular lasers, and stents. As this technology continues to evolve, treatment options will expand and morbidity will continue to decline. The indications for treatment using minimally invasive surgical techniques will alter current management for these difficult and challenging vascular disorders.

Transcranial clipping of recurrent cerebral aneurysms after endovascular treatment.

Treatment of intracranial aneurysms by interventional neurovascular techniques may be useful as a therapeutic alternative. We describe two cases of recurrent aneurysms after endovascular treatment using detachable balloons. Two cases are reported of recurrence 2 years after endovascular treatment of cerebral aneurysms (posterior communicating in both cases). One patient had a subarachnoid hemorrhage after rupture of a posterior communicating aneurysm. The other patient had an aneurysm diagnosed incidentally after a contrast-enhanced computed tomographic scan of the head for an unrelated problem. Endovascular balloon embolization of both aneurysms was performed without any immediate complication. Two years after treatment, a cerebral angiogram showed recurrent aneurysms. Surgical clipping excluded both aneurysms definitely. These cases highlight the importance of control angiography at long-term follow-up and emphasize the significance of balloon migration after endovascular treatment of aneurysms.

Intracranial aneurysms: interventional neurovascular treatment with detachable balloons--results in 215 cases.

Patients with complex or surgically difficult intracranial aneurysms are being treated with interventional neurovascular techniques. With neuroleptic anesthesia and a transfemoral femoral approach, a silicone micro-balloon can be flow directed through the intracranial circulation, guided directly into the aneurysm, and detached. The aneurysm is thus eliminated from the circulation, and the parent artery is preserved. For broad-based or ectatic aneurysms, test occlusion followed by permanent occlusion of the aneurysm and parent vessel can be performed. Since 1981, 211 patients with 215 aneurysms, including 177 cases involving the anterior and 38 cases involving the posterior circulation, have been treated with this technique. In 127 cases (59.1%), the parent vessel was occluded; in 88 cases (40.9%), primary occlusion of the aneurysm was achieved with preservation of the parent artery. Therapy-related complications included 21 deaths (9.8%) and 16 strokes (7.4%). Follow-up examinations were performed at 1, 3, and 12 months after treatment, and follow-up ranged from 5 months to 9 years. In patients in whom standard surgical therapy fails or for aneurysms in surgically inaccessible anatomic locations, interventional techniques that make use of detachable balloons may be a useful therapeutic alternative.

Interventional neurovascular treatment of a giant intracranial aneurysm using platinum microcoils

A 70-year-old woman presented with symptoms of progressive cerebellar dysfunction due to mass effect from a giant, expanding, posterior fossa aneurysm arising from the distal vertebral artery. The aneurysm contained thrombus and had a broad-based neck. From a transfemoral approach, with the patient under local anesthesia, a 2.2 French microcatheter was guided through the vertebral artery and placed directly into the aneurysm. Six 5 × 15-mm platinum microcoils were deposited into the residual lumen of the aneurysm, resulting in complete thrombosis with obliteration of the aneurysm and preservation of the parent artery. Endovascular coil embolization therapy by interventional neurovascular techniques may provide a therapeutic alternative in the management of surgically difficult symptomatic intracranial aneurysms.

Endovascular detachable balloon embolization therapy of cavernous carotid artery aneurysms: results in 87 cases

Interventional neurovascular techniques for treating patients with intracranial aneurysms are now being performed in selected cases. In certain anatomical locations that are difficult to reach surgically, such as the cavernous portion of the internal carotid artery (ICA), this technique may be especially useful. The procedure is performed from a transfemoral approach, using local anesthesia, thus permitting continuous neurological monitoring. Between 1981 and 1989, 87 patients diagnosed as having an intracavernous aneurysm were treated with endovascular detachable balloon embolization techniques. The patients ranged in age from 11 to 84 years. The presenting symptom was mass effect in 69 cases (79.3%), rupture of a preexisting aneurysm resulting in a carotid-cavernous sinus fistula in eight cases (9.2%), trauma resulting in a cavernous pseudoaneurysm in seven cases (8.0%), and hemorrhage in three cases (3.4%). Therapeutic occlusion of the ICA across or just proximal to the aneurysm neck was performed in 68 patients (78.2%). Since 1984, with the development of a permanent solidifying agent (2-hydroxyethyl methacrylate) to fill the balloon, it is now feasible in some cases to guide the balloon directly into the aneurysm and preserve the parent artery; this was achieved in 19 cases (22%). Follow-up examination has demonstrated complete thrombosis with partial or total alleviation of symptoms in all patients with therapeutic occlusion of the parent vessel. Of the 19 patients with preservation of the parent artery, follow-up studies have demonstrated total exclusion in 12 cases (63%) and subtotal occlusion of greater than 85% in seven cases (37%), with clinical improvement in all cases. Complications from therapy included transient cerebral ischemia during or after therapy requiring volume expansion in seven cases, embolic symptoms requiring antiplatelet medication in two cases, and stroke in four cases; there were no deaths. Detachable balloon embolization therapy, particularly for large and giant symptomatic aneurysms of the cavernous ICA, can be an effective mode of treatment.

Endovascular treatment of intracranial aneurysms with a new silicone microballoon device: technical considerations and indications for therapy.

Treatment of complex intracranial aneurysms by means of interventional neurovascular techniques is now being performed with a newly developed silicone detachable-microballoon device. The balloon is composed of unique silicone elastomers that are extremely soft and malleable. It therefore conforms to the blood vessel lumen or aneurysm wall and reduces the risk of rupture. It is affixed onto a 2.0-F catheter and can be either directed by flow or guided with the catheter. For aneurysms with a well-defined neck, the balloon is placed directly into the aneurysm, inflated with 2-hydroxyethyl methacrylate for permanent solidification, and detached. The aneurysm is thus excluded from the circulation, and the parent vessel is preserved. For aneurysms without a well-defined neck, test occlusion can be performed, followed by permanent balloon occlusion of the parent vessel. This balloon technique has been successfully used to treat aneurysms in both the anterior and posterior circulations, where standard neurosurgical techniques have failed, and in surgically inaccessible anatomic locations.

Interventional neurovascular treatment of traumatic carotid and vertebral artery lesions: results in 234 cases.

Traumatic injuries to the head and neck that result in arteriovenous fistulae are often difficult to treat by direct surgical access. This is because of anatomic location, instability of the acutely injured patient, and difficulty in localizing the exact site of injury. Between 1974 and 1988, 234 consecutive cases of traumatic injuries to the carotid or vertebral artery were evaluated by our group for intravascular embolization therapy. This included 206 cases of direct and seven cases of indirect carotid-cavernous sinus fistulae and 21 cases of traumatic vertebral fistulae. A variety of devices including detachable balloons, liquid tissue adhesives, microcoils, and silk suture were used with the goal of fistula occlusion and preservation of the parent vessel. This was achieved in 193 cases (82%). In the remaining 41 cases (18%), the carotid or vertebral artery had to be occluded by endovascular occlusion techniques because of extensive vascular injury in 28 cases and subtotal occlusion of the fistula in 13 cases. Complications included transient cerebral ischemia in six cases, pseudoaneurysm formation in five cases, stroke in five cases, and peripheral nerve injury in one case. The development of interventional neurovascular techniques has altered the management of these acutely injured patients. The preferred method for treatment has shifted from direct surgical access under general anesthesia to endovascular therapy under local anesthesia.