Interventional Neuroradiology Intraarterial Balloon Assisted  Thrombolysis for Acute Ischemic Stroke From Neurovascular Newsletter October 1998
The Interventional Neuroradiology service at Massachusetts General Hospital and the MGH Brain Aneurysm & AVM Center.

The most common cause for exclusion of patients from treatment with intravenous rt-PA has been their presentation beyond the three hour time window. In various trials, the benefit of intravenous agents has been limited by the hemorrhagic complications, usually occurring in patients treated late. It has been shown that direct intraarterial infusion of thrombolytic may improve recanalization of an occluded vessel with less systemic effect and at a potentially lower relative dose than systemic thombolytics, thereby reducing the hemorrhagic risk.

Many institutions in the United States and throughout the world have been gaining experience over the past decade with direct intraarterial infusion of thrombolytics, although until recently no controlled trials have been published (reference 2). Direct intraarterial infusion of Urokinase has been used commonly to treat occlusions of the proximal anterior or middle cerebral arteries, the basilar artery, and the internal carotid artery. Most institutions treating patients endovascularly have successfully extended the time from symptom onset to treatment beyond that used for intravenous rt-PA, thus possibly allowing more patients to be treated. At our institution and others, patients with anterior cerebral, middle cerebral, or internal carotid artery thromboembolic occlusions are considered for emergent treatment if they present within 6 hours of symptom onset. Because patients with basilar artery occlusions frequently have a fluctuating course, they may be considered for treatment up to 24 to 48 hours from symptom onset (reference 3).

All patients presenting with potential ischemic stroke at our institution are sceened clinically and have had nonenhanced head computerized tomography (CT) to exclude hemorrhage. Patients have also had CT angiography confirming major vessel occlusion and have possibly had magnetic resonance imaging with diffusion weighted imaging. Relative contraindications to intraarterial thrombolysis include a history of recent stroke or surgery, known intracranial tumor or vascular lesion, recent prior head trauma, active or recent hemorrhage elsewhere in the body, recent myocardial infarction, hemorrhagic diathesis, etc. Late presentation to treatment as well as very minor or very severe stroke symptoms may also exclude patients from treatment.

In an attempt to overcome the contraindications to treatment and to recanalize vessels faster, several institutions have begun using various devices in conjunction with or instead of conventional thromblytics. Mechanical embolectomy has recently been reported using a commercially available microsnare (reference 4). Experiments with various novel mechanical devices as well as ultrasound and laser based devices have begun, although these are not yet readily available for clinical use.

We have begun using mechanical balloon clot disruption in addition to intraarterial thrombolytics (Urokinase) in acute stroke patients (figure). We have performed balloon angioplasty of the embolus in 11/68 cases of acute stroke treated by intra-arterial thrombolysis because of a failure of urokinase to restore flow (6 patients), coexistent contraindication to urokinase (2 patients), or late presentation to treatment (3 patients). Four middle cerebral artery (MCA), 4 basilar artery, 2 internal carotid artery (ICA), and 1 combined ICA/MCA occlusion were treated.

Occlusions were restored to TIMI grade 3 in 7/11 (complete recanalization), TIMI grade 2 (partial recanalization) in 3/11 patients, and TIMI grade 1 (minimal recanalization) in 1/11 patients. Distal emboli were seen in all patients as is frequently seen with urokinase alone, and were variably treated with selective intra-arterial urokinase. No vessel dissections or ruptures occurred from the balloon angioplasty. Excellent or good outcome on discharge or latest follow up evaluation was found in 27% (3/11) of patients. Outcome was graded as fair in 2 and poor in 3 patients. Three patients died.

Our initial experience suggests that recanalization of embolic occlusions can be consistently achieved with mechanical balloon clot disruption which may permit satisfactory outcome in some patients not treatable with urokinase alone. Other newer technologies may further expand the possibilities for acute stroke therapy. Patient and physician knowledge of the symptoms and signs of acute stroke, as well as their awareness of the possibility of newer stroke therapies will become more important as the treatment of this important disease evolves.

References:

1. The National Institute of Neurological Disorders, and Stroke rt-PA Stroke Study Group. Tissue Plasminogen Activator for Acute Ischemic Stroke. New England Journal of Medicine. 1995;333:1581-1587.
2. del Zoppo GJ, Higashida RT, Furlan AJ, et al. PROACT: A Phase II Randomized Trial of Recombinant Pro-Urokinase by Direct Arterial Delivery in Acute Middle Cerebral Artery Stroke. Stroke. 1998;29(1):4-11.
3. Barnwell SL, Clark WM, Nguyen TT, et al. Safety and Efficacy of Delayed Intraarterial Urokinase Therapy with Mechanical Clot Disruption for Thromboembolic Stroke. American Journal of Neuroradiology. 1994;15:1817-1822.
4. Wikholm G. Mechanical Intracranial Embolectomy. Interventional Neuroradiology. 1998;4(2):159-164.

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The Interventional Neuroradiology service at Massachusetts General Hospital and the MGH Brain Aneurysm/AVM Center.