Abstract and Introduction
Abstract
Intracerebral hemorrhage (ICH) secondary to intravenous and intraarterial revascularization strategies for emergent treatment of acute ischemic stroke is associated with high mortality. ICH from systemic thrombolysis typically occurs within the first 24–36 hours of treatment initiation and is characterized by rapid hematoma development and growth. Pathophysiological mechanisms of revascularization therapy-induced ICH are complex and involve a combination of several distinct processes, including the direct effect of thrombolytic agents, disruption of the blood-brain barrier secondary to ischemia, and direct vessel damage from wire and microcatheter manipulations during endovascular procedures. Several definitions of ICH secondary to thrombolysis currently exist, depending on clinical or radiological characteristics used. Multiple studies have investigated clinical and laboratory risk factors associated with higher rates of ICH in this setting. Early ischemic changes seen on noncontrast CT scanning are strongly associated with higher rates of hemorrhage. Modern imaging techniques, particularly CT perfusion, provide rapid assessment of hemodynamic parameters of the brain. Specific patterns of CT perfusion maps can help identify patients who are likely to benefit from revascularization or to develop hemorrhagic complications. There are no established guidelines that describe management of revascularization therapy–induced ICH, and great variability in treatment protocols currently exist. General principles that apply to the management of spontaneous ICH might not be as effective for revascularization therapy–induced ICH. In this article, the authors review current knowledge of risk factors and radiological predictors of ICH secondary to stroke revascularization techniques and analyze medical and surgical management strategies for ICH in this setting.
Introduction
According to the most recent report from the American Heart Association, 795,000 people in the US experience a new or recurrent stroke each year, and 87% of these strokes are ischemic. Despite advances in treatment and rehabilitation strategies, stroke remains the leading cause of long-term disability in adults. A short time window for treatment (within the first 4.5 hours of stroke onset) and late arrival to the hospital are major barriers preventing many patients from receiving IV thrombolysis. Careful analysis of acute stroke care provided at multiple hospitals in the US shows that even some patients with no absolute contraindications for thrombolysis who present to the emergency department within the "therapeutic window" do not receive recommended thrombolytic therapy. Intracerebral hemorrhage secondary to thrombolysis is associated with high mortality and remains the most feared complication of acute stroke treatment. In fact, it is often cited as a primary reason preventing patients from receiving fibrinolytic agents to restore blood flow to the brain.
Endovascular interventions with IA thrombolytic agents or by means of mechanical revascularization strategies demonstrate high recanalization rates in strokes with large artery occlusion and can be performed with an extended time window or when contraindications for IV thrombolysis are present. Theoretical models have projected that IA therapies for acute stroke secondary to large-vessel occlusion will be used in up to 10,400–41,500 cases per year in the US. However, similar to IV thrombolysis, endovascular interventions carry a risk of ICH. Recent advances in stroke imaging allow selection of patients who can benefit the most from revascularization and prediction of which patients are at higher risk for hemorrhagic complications.
In this article, we review the current literature on clinical and laboratory risk factors and radiological predictors of ICH secondary to IV and IA revascularization therapies in patients presenting with acute ischemic stroke, as well as analyzing strategies for managing this iatrogenic complication.