Atherosclerotic Plaque in the Left Carotid Artery Is More Vulnerable Than in the Right

Background and Purpose—

Ischemic stroke is more often diagnosed in the left hemisphere than in the right. It is unknown whether this asymmetrical prevalence relates to differences in carotid atherosclerosis. We compared atherosclerotic plaque prevalence, severity, and composition between left and right carotid arteries.

Methods—

In a population-based cohort, carotid MRI scanning was performed in 1414 stroke-free participants (≥45 years). Using a multisequence MRI protocol, we assessed the prevalence, stenosis, and thickness of the plaque and its predominant component (ie, lipid core, intraplaque hemorrhage, calcification, or fibrous tissue in each carotid artery). Differences between left and right side were tested using paired t tests, McNemar test and Generalized Estimating Equation analyses.

Results—

The majority (85%) of the participants had bilateral carotid plaques. Unilateral plaques were twice more prevalent on the left than on the right side (67% versus 33%; P <0.001). Plaque thickness was also greater on the left (3.1±1.2 versus 2.9±1.3 mm; P <0.001); degree of stenosis did not differ. Intraplaque hemorrhage and fibrous tissue were more prevalent on the left (9.1 versus 5.9%; P <0.001 and 45.0 versus 38.5%; P <0.001), whereas calcification occurred more often on the right (37.4 versus 31.6% at the left; P <0.001). Lipid was equally distributed.

Conclusions—

Carotid atherosclerotic plaque size and composition are not symmetrically distributed. Predominance of intraplaque hemorrhage in left-sided carotid plaques suggests a greater vulnerability as opposed to right-sided plaques, which are more calcified and therefore considered more stable.

[Intersphincteric ligation of perianal fistula]

Fistulotomy is inappropriate for patients with a high transsphincteric fistula, passing through the upper or middle third of the external anal sphincter, because this procedure requires division of a large part of the anal sphincter, with subsequent risk of fecal incontinence. Therefore, sphincter preserving procedures have been developed for the treatment of high transsphincteric fistulas, such as flap repair. In most hospitals, fistulotomy is still the treatment of choice for low transsphincteric fistula, passing through the lower third of the external anal sphincter. Although this procedure is considered simple and effective with a minimal risk of incontinence, data suggest that the risk of diminished fecal continence is not insignificant. Ligation of the intersphincteric fistula tract (LIFT) is a new sphincter preserving technique. This technique may be a sphincter preserving alternative for fistulotomy in low transsphincteric fistulas and for flap repair in high transsphincteric fistulas.