Ischemic stroke--novel therapeutic strategies

Cerebral ischemia and neuroregeneration

Cerebral ischemia is one of the leading causes of morbidity and mortality worldwide. Although stroke (a form of cerebral ischemia)-related costs are expected to reach 240.67 billion dollars by 2030, options for treatment against cerebral ischemia/stroke are limited. All therapies except anti-thrombolytics (i.e., tissue plasminogen activator) and hypothermia have failed to reduce neuronal injury, neurological deficits, and mortality rates following cerebral ischemia, which suggests that development of novel therapies against stroke/cerebral ischemia are urgently needed. Here, we discuss the possible mechanism(s) underlying cerebral ischemia-induced brain injury, as well as current and future novel therapies (i.e., growth factors, nicotinamide adenine dinucleotide, melatonin, resveratrol, protein kinase C isozymes, pifithrin, hypothermia, fatty acids, sympathoplegic drugs, and stem cells) as it relates to cerebral ischemia.

Patient selection for intra-arterial cerebral revascularization in acute ischemic stroke

In acute ischemic stroke, rapid revascularization of the cerebral 'penumbra volume' is the key to better patient outcome. The largest and most proximal cerebral thrombotic artery occlusions can in most cases only be opened by intra-arterial intervention. The use of intra-arterial revascularization is rapidly expanding throughout Europe and North America, despite the risk for serious complications and the fact that the benefit of this treatment has not yet been proven in large, randomized clinical trials. Oslo University Hospital has performed approximately 60 intra-arterial procedures annually in acute ischemic stroke during the last few years. In this paper, we discuss important clinical and ethical aspects learned from our own experience. The future of intra-arterial cerebral revascularization will depend on an accurate preintervention patient selection.

Acute ischemic stroke--from symptom recognition to thrombolysis

OBJECTIVES

The understanding of stroke has changed in the recent years from rehabilitation to an emergency approach. We review existing data from symptom recognition to thrombolysis and identify challenges in the different phases of patient treatment.

RESULTS

Implementation of treatment in dedicated stroke units with a multidisciplinary team exclusively treating stroke patients has led to significant reduction of stroke morbidity and mortality. Yet, first the introduction of treatment with intravenous rtPA (IVT) has led to the 'time is brain' concept where stroke is conceived as an emergency. As neuronal death in stroke is time dependent, all effort should be laid on immediate symptom recognition, rapid transport to the nearest hospital with a stroke treatment facility and diagnosis and treatment as soon as possible. The main cause of prehospital delay is that patients do not recognize that they suffered a stroke or out of other reasons do not call the Emergency Medical Services immediately. Educational stroke awareness campaigns may have an impact in increasing the number of patients eligible for rtPA treatment and can decrease the prehospital times if they are directed both to the public and to the medical divisions treating stroke. Stroke transport times can be shortened by the use of helicopter and a stroke mobile--an ambulance equipped with a CT scanner--may be helpful to decrease time from onset to treatment start in the future. Yet, IVT has several limitations such as a narrow time window and a weak effect in ischemic strokes caused by large vessel occlusions. In these cases, interventional procedures and the concept of bridging therapy, a combined approach of IVT and intraarterial thrombolysis or mechanical thrombectomy, might improve recanalization rates and patient outcome.

CONCLUSIONS

As neuronal death in stroke patients occurs in a time-dependent fashion, all effort should be made to decrease time from symptom onset to treatment start with rtPA: major challenges are stroke recognition in the public, transport times to hospital and an efficient stroke triage in the hospital.