Embolism major stroke

Ischemic strokes account for around 80-85% of all strokes and are caused by arterial vascular occlusions rarely occlusion in the cerebral venous system may result in ischemic and/or hemorrhagic stroke. Arterial occlusions resulting from cerebral embolism are the most common causes of ischemic strokes, and by about one week after stroke as many as 70-90% of occlusions will have spontaneously recanalized. Emboli typically originate from atherosclerotic stenoses in the internal carotid artery or from sources in the heart such as clots in the left atrium or the left ventricle. Hypertension-induced vascular disease of the small perforating intracerebral arteries is a common cause of lacunar strokes. A classification of the major stroke subtypes is shown in Table 31.1. 

Long-term follow-up of patients treated with embolization has been reported in several studies [11,40, 55, 60, 71, 77]. In a recent study, the long-term outcomes of embolization (mean follow-up 62 months), were successful in 83% of 112 treated patients overall and in 96% of patients in whom all angiographi-cally visible PAVMs were embolized [40]. During the follow-up after embolization major neurological complications such as cerebral abscess, transient ischemic attack, or stroke related to reperfused treated or new PAVMs have been reported [11,25,40, 77]. The long-term morbidity of reperfused PAVMs is unknown but some patients have already suffered from stroke because of recanalized PAVMs [40]. 

In general, arterial thrombi are platelet-rich ( white clots ) and form at ruptured atherosclerotic plaques, leading to intraluminal occlusion of arteries that can result in end-organ injury (e.g., myocardial infarction, stroke). In contrast, venous thrombi consist mainly of fibrin and red blood cells ( red clots ), and usually form in low-flow veins of the limbs, producing deep vein thrombosis (DVT) the major threat to life results when lower extremity (and, occasionally, upper extremity) venous thrombi embolize via the right heart chambers into the pulmonary arteries, i.e., pulmonary embolism (PE). 

Cl 0.08-0.96) and symptomatic pulmonary embolism (PE) (OR 0.34, 95% Cl 0.17-0.69), but an increase in major extracranial hemorrhage when compared to placebo (OR 2.17, 95% Cl 1.10. 28). Nonsignificant reductions in combined death and disability, as well as increases in case fatality and sICH were also observed. The authors concluded that insufficient evidence existed to support the routine use of LMWH in the management of patients with ischemic stroke. 

Carotid artery disease is one of the major causes of ischemic stroke. The predominant mechanisms by which it causes stroke are (a) arterial embolism from atherosclerotic plaques (b) hemodynamic changes, leading to watershed infarcts and (c) distal propagation of thrombus originating from acute carotid occlusion. ... 

More than 50% of patients with cerebral embolism have atrial fibrillation. In the majority of these patients, the underlying cardiac disease is nonvalvular. The risk of ischemic stroke and atrial fibrillation increases with age, reaching a cumulative risk of 35% during a patient s lifetime. Combined results from several randomized trials show that warfarin reduces the risk of stroke in patients with nonrheumatic atrial fibrillation by 68% (to 1.4% per year), with an excess incidence of major hemorrhage (including intracranial) of only 0.3% per year. 

This was systematically studied with DWI in 62 consecutive patients who presented with a classic lacunar syndrome (Ay et al. 1999). DWI showed subsidiary acute lesion(s) in addition to the index lacunar lesion in ten patients (16%). The additional lesions were punctuate and lay within the leptomen-ingeal arterial territories in the majority. Patients with subsidiary infarction(s) more frequently harbored an embolic cause of stroke. This finding is critical because underlying embolic cause may give rise to recurrent strokes with more extensive brain injury. Identification of subsidiary infarctions on DWI should have an impact in prompting the physician to introduce the best effective treatment for secondary stroke prevention in a patient with lacunar infarction. 

Q17 There are some major problems associated with oestrogen-replacement therapy. These include pulmonary embolism, thromboembolism, seizures, hepatic adenoma and risk of stroke. There is also now evidence of an increased incidence of breast, ovarian and endometrial cancer, which is related to the duration of HRT use. Approximately 14 in every 1000 women aged 50-64 years not using HRT develop breast cancer. Use of oestrogen-only HRT for five years in this age group increases the incidence of breast cancer to about 15.5 in every 1000 women this represents a relatively small increase in risk. 

Schmahmann JD (2003). Vascular syndromes of the thalamus. Stroke 34 2264-2278 Schulz UG, Rothwell PM (2001). Major variation in carotid bifurcation anatomy a possible risk factor for plaque development Stroke 32 2522-2529 Scott BL, Jankovic J (1996). Delayed-onset progressive movement disorders after static brain lesions. Neurology 46 68-74 Wardlaw JM, Merrick MV, Ferrington CM et al. (1996). Comparison of a simple isotope method of predicting likely middle cerebral artery occlusion with transcranial Doppler ultrasound in acute ischaemic stroke. Cerebrovascular Diseases 6 32-39 Wardlaw JM, Lewsi SC, Dennis MS etal. (1999). Is it reasonable to assume a particular embolic source from the type of stroke Cerebrovascular Diseases 9(Supp 1) 14... 

The main outcome in the APT overview was the occurrence of a serious vascular event (i.e. non-fetal myocardial infarction (MI), non-fetal stroke or vascular death). Where rqrpropriate, information on major bleeding, deep venous thrombosis, pulmonaty embolism and arterial or graft occlusion was also sought. 

Patients with a high risk for clotting require thromboprophylaxis. Some risk factors for venous thromboembolism include age greater than 40 years, prolonged immobility, history of prior venous thromboembolism (DVT, pulmonary embolism [PE]), cancer, major surgery (abdominal, pelvic, or lower extremity), fracture (pelvis, hip, or leg), CHF, Ml, stroke, obesity, and high-dose estrogen use. 

A major clinical role of CTA in acute ischemic stroke management remains the exclusion of unnecessary lA thrombolytic therapy in patients presenting with acute embolic stroke, but who do not have large... 

Comparative studies In the RE-LY study 18113 patients with non-valvular atrial fibrillation were randomized to dose-adjusted warfarin targeting an INR of 2.0-3.0 or dabigatran 110 or 150 mg bd [39 ]. The primary outcome was the incidence of stroke or systemic embolism, while the primary safety end-point was the frequency of major bleeding. Compared with warfarin, dabigatran 150 mg bd reduced the incidence of the primary outcome (1.7% per year with warfarin versus 1.1% per year with dabigatran 150 mg bd RR = 0.66 95% CI=0.53, 0.82) and had a similar effect on major bleeding. Patients... 

Goodman SG, Wojdyla DM, Piccini JP, et al Factors associated with major bleeding events insights from the ROCKET AF trial (rivaroxaban once-daily oral direct factor Xa inhibition compared with vitamin K antagonism for prevention of stroke and embolism trial in atrial fibrillation). J Am Coll Cardiol 2014 63 891-900. 

TPA is also under clinical trials for the treatment of unstable angina, ischaemic stroke, acute stroke and pulmonary embolism. A major competitor of TPA is streptokinase, which is a bacterial enzyme. Hiis compound is cheaper and may be more effective than TPA in some respects although there is a higher risk of allergenic response. 

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