Multimodal reperfusion therapy for large hemispheric infarcts in octogenarians: is good outcome a realistic goal?

BACKGROUND AND PURPOSE

MMRT may be beneficial in a subset of patients with large hemispheric stroke who cannot be treated with systemic thrombolysis. Because most previous studies only included relatively young patients, the outcome of very old patients given MMRT remains unknown.

MATERIALS AND METHODS

Consecutive patients with large hemispheric stroke treated with MMRT and admitted to intensive care were included. We compared neurologic and functional outcomes between patients younger and older than 80 years.

RESULTS

We included 14 patients older than 80 years and compared them with 66 patients who were younger than 80. Cerebrovascular risk factor profile, admission NIHSS scores, stroke etiology and pathogenesis, and procedure-related variables did not differ between the groups except for a higher prevalence of smoking in younger patients. Excellent target vessel recanalization (Thrombolysis in Myocardial Infarction score of 3) and good outcome at 90 days (modified Rankin Score ≤ 2) were more common in younger patients (45% versus 14%, P = .047, and 41% versus 0%, P = .008, respectively). In contrast, mortality rates were higher in octogenarians (43% versus 17%, respectively).

CONCLUSIONS

In this study, very old patients had higher chances of mortality and a very low probability of achieving functional independence even after MMRT. Further prospective studies are needed to examine the futility of MMRT in the very old.

Successful endovascular treatment of a growing megadolichoectasic vertebrobasilar artery aneurysm by flow diversion using the "diverter-in-stent" technique

Giant dolichoectatic and fusiform aneurysms of the vertebrobasilar artery are among the most difficult and dangerous aneurysms to treat. Conservative management may be reasonable in asymptomatic elderly patients. Nevertheless, due to the frequent presence of mass effect on the brainstem and the risks of thromboembolic events and rupture, these aneurysms often demand treatment rather than observation. With the advancement of endovascular techniques some of these lesions have become treatable without the high morbidity and mortality rates associated with open surgical treatment. When dealing with giant, progressively enlarging symptomatic aneurysms, more limited therapeutic alternatives are available. The authors present a case of a growing megadolichoectatic vertebrobasilar artery aneurysm causing major disability due to increasing mass effect in a 51-year-old man. The aneurysm was treated with flow diversion by placing multiple telescoped stents and diverters ("diverter-in-stent" technique), achieving thrombosis of the aneurysm and reduction of the mass effect on the brainstem, with neurological improvement. The successful clinical and angiographic results observed in our case of giant dolichoectasic vertebrobasilar aneurysm contribute to the literature on giant aneurysms treated by means of flow diversion.

Visual failure and recovery after thrombosis of a giant carotid ophthalmic aneurysm following vascular bypass and carotid artery ligation

Thrombosis via Hunterian ligation, with or without high-flow bypass, is the definitive treatment for unclippable giant aneurysms; however, secondary deterioration may occur. We present a 67-year-old woman with an unclippable giant (33mm) carotid ophthalmic aneurysm. High-flow external carotid artery to middle cerebral artery bypass and proximal cervical internal carotid artery Hunterian ligation achieved complete thrombosis. Subsequent expansion of the thrombosed aneurysm created mass effect with hydrocephalus, leading to marked cognitive and visual decline. Aneurysmal decompression led to improved vision and near-normal neurological function.

Convexity properties of products of random nonnegative matrices

Consider a sequence of N x N random nonnegative matrices in which each element depends on a vector u of parameters. The nth partial product is the random matrix formed by multiplying, from right to left, the first n of these random matrices in order. Under certain conditions, the elements of the nth partial product grow asymptotically exponentially as n increases, and the logarithms of the discrete long-run growth rates are convex functions of u. These conditions are met by some models in statistical mechanics and demography. Consequently, the Helmholtz free energy is concave and the population growth rate is convex in these models.

Food webs and the dimensionality of trophic niche space

If the trophic niche of a kind of organism is a connected region in niche space, then it is possible for trophic niche overlaps to be described in a one-dimensional niche space if and only if the trophic niche overlap graph is an interval graph. An analysis of 30 food webs, using the combinatorial theory of interval graphs, suggests that a niche space of dimension 1 suffices, with unexpectedly high frequency and perhaps always, to describe the trophic niche overlaps implied by real food webs in single habitats. Consequently, real food webs fall in a small subset of the set of mathematically possible food webs. That real food webs are compatible with one-dimensional trophic niche spaces, more often than can be explained by chance alone, has not been noticed previously.

Predictive validity and measurement issues in documenting quit intentions in population surveillance studies

INTRODUCTION

Discrete classification of smokers by intention to quit is desirable in many public health and clinical settings.

METHODS

Two methodological studies examine measurement properties of measures of discrete-time intention to quit smoking used in population-based tobacco surveillance surveys: an ecological comparison of rates of positive intention in relation to the form of measure used and a prospective analysis examining predictive validity of self-reported quit intentions using multiple possible points of dichotomization of an ordinal measure of intention to quit. The prospective analysis used a repeated measures design and follow-up to 1 year for 2,047 smokers in the Ontario Tobacco Survey cohort.

RESULTS

The estimated percent of smokers intending to quit was significantly higher using the Stages of Change intention measure, relative to another single question measure. Significant dose-response effects were found. The sooner one intended to quit the more likely one was to make an attempt or achieve at least 30 days abstinence in the next 6 months. Intending to quit in a month or later was not associated with cessation during follow-up among respondents without prior attempts. Examination of cutpoints revealed no value, which maximized both positive and negative prediction. Regardless of quit attempt history, greatest predictive validity was found where respondents stated that they had no intention at all.

DISCUSSION

Measures of intentions quit smoking in specific time periods and expressed as dichotomies have limited psychometric properties but utility in applied research. Our findings suggest a possible measurement effect warranting caution in comparisons across studies.

Therapeutic modalities in symptomatic intracranial arterial occlusive disease

Intracranial atherosclerotic disease (ICAD) is a frequent cause of stroke that is sometimes underdiagnosed. In this review, we survey the literature concerning ICAD and present the prognostic factors and the therapeutic options pertinent to it by comparing medical, surgical and endovascular approaches.

Modeling the population dynamics of a cuckoo-host association and the evolution of host defenses

Cuckoo parasitism in Nagano Prefecture in Japan has shown dramatic changes in the parasitism rate, host usage by the cuckoo, and defensive behavior of hosts during the past 60 yr. To gain insights into these phenomena, we model the population dynamics of a cuckoo-host association together with the population genetics of a rejecter gene in the host population. Analysis shows that both the dynamical change in the host-parasite association and the establishment of the host's counteradaptation crucially depend on the product of two factors, the carrying capacity of the host and cuckoo's searching efficiency. When the product is less than a critical value, the host population cannot evolve a counteradaptation even if parasitized by the cuckoo. Hence, the lack of counteradaptation does not necessarily imply that the host population only recently has become parasitized. As the product becomes larger, the rejection behavior will be eventually established at higher levels in the host population In this case, the spreading of rejection behavior is very fast, which suggests that the cuckoo-host association reaches an equilibrium state within a relatively short period. These results make possible new interpretations of several circumstances reported about cuckoo-host associations.

RESULTS OF ENDOVASCULAR TREATMENT OF TRAUMATIC INTRACRANIAL ANEURYSMS

OBJECTIVE

To present results of early angiographic diagnosis and endovascular treatment of traumatic intracranial aneurysms (TICA).

METHODS

From June 2002 to December 2006, diagnostic angiography was performed on patients with moderate to severe traumatic brain injury that involved a cranial base fracture or a penetrating brain injury with a tract from the penetrating agent that entered at the pterional area, went through the middle cerebral artery candelabra, and crossed the midline. TICAs were treated by various endovascular techniques during the same angiographic procedure.

RESULTS

Thirty-four patients with traumatic brain injury underwent angiography (25 penetrating brain injuries, nine blunt injuries); 13 TICAs were diagnosed (10 penetrating brain injuries, three blunt injuries). The Glasgow Coma Scale score at diagnosis ranged from 5 to 15. Angiography was performed for screening in eight patients and for clinical indications in five patients; 11 TICAs were diagnosed before rupture. Seven aneurysms were located on branches of the middle cerebral artery, two on pericallosal branches of the anterior cerebral artery, and four on the internal carotid artery. No recanalization was detected in 12 patients. One patient treated with a bare stent and coiling had a growing intracavernous pseudoaneurysm; therefore, internal carotid artery occlusion with extracranial-intracranial microvascular bypass was performed. Six patients refused angiographic follow-up, but computed tomographic angiography has failed to show recanalization. No patient presented with delayed bleeding (mean follow-up, 2.6 yr). There were no procedure-related complications or mortality.

CONCLUSION

Early angiographic diagnosis with immediate endovascular treatment provided an effective approach for TICA detection and management. Endovascular therapy is versatile and offers a valuable alternative to surgery, allowing early aneurysm exclusion with excellent results.

Endovascular treatment of congenital carotid-cavernous fistulas in infancy

Congenital dural arteriovenous fistulas have been infrequently described in pediatric population and they generally affect the transverse, sigmoid, straight or sagittal sinuses. Congenital carotid-cavernous fistulas in infancy are considered very rare and to our knowledge, only four cases have been reported in literature. Currently, the preferred treatment is endovascular embolization through trans-arterial route. We review the literature on congenital carotid cavernous fistulas in infancy focusing on the endovascular treatment of this rare entity and present our experience.