Demonstration of the Glagov phenomenon in vivo by CT coronary angiography in subjects with elevated Framingham risk

Abstract

Computed tomography coronary angiography (CTA) is a novel, non-invasive method for coronary plaque detection and quantification. We hypothesized that CTA can detect early vessel wall thickening with preserved luminal size in patients without known coronary artery disease and intermediate/high Framingham Risk Score (FRS) compared to those with low FRS. Vessel-wall and plaque geometrical and compositional parameters were measured on CTA in 375 coronary segments with a highly standardized method. These parameters were then compared in patients with low versus intermediate/high FRS. The relationship between coronary artery calcium by non-contrast CT scanning (Agatston score) and percent atheroma volume (PAV) was determined by linear regression. P value <0.05 was considered significant. PAV and remodeling index were significantly higher in patients with intermediate/high FRS compared to those with low FRS (45.9 ± 6.8 vs. 42.3 ± 6.7; P = 0.004) and (0.97 ± 0.15 vs. 0.92 ± 0.13; P = 0.04), while minimal luminal diameter and minimal luminal area were similar. There was significant correlation between Agatston score and PAV (r(2) = 0.42, P = 0.0036). However, Agatston score and plaque compositional parameters were similar between the groups. In conclusion, we demonstrated that CTA can detect early vessel-wall thickening with preserved luminal size in patients with intermediate/high versus low FRS.

Compensatory enlargement of Ossabaw miniature swine coronary arteries in diffuse atherosclerosis

“…1A). Several studies [1], [2], [3], [4], [5], [6], [7], [8] have shown arterial positive remodeling in the presence of focal disease but to our knowledge, this is the first report of a compensatory enlargement of the coronary arteries in a metabolic syndrome animal model with DCAD during the early stages of the disease.…”

“…Further accumulation of plaque resulted in decrease of lumen area. Since then, several studies have demonstrated the “Glagov phenomenon” in coronary arteries [1], [3] and peripheral arteries [8] of patients undergoing IVUS [1], [3], [8] or CCTA [6]. It has been suggested [26] that the increase in lumen CSA is largely compensatory; i.e., an adaptation to thickness of the intima to preserve vessel function.…”

“…It has also been reported [2] that the capacity for compensatory positive remodeling ceases when the plaque occupies approximately 40% of the potential lumen area. The phenomenon was described in a histological autopsy study twenty five years ago [2] and has since been demonstrated in vivo in humans using intravascular ultrasound (IVUS) [1], [3], [5], [7], [8], epicardial echocardiogram [4], and contrast enhanced computed tomographic angiography (CCTA) [6].…”

“…Post-mortem and in vivo studies suggest that coronary artery diameter increases as a consequence of atherosclerosis [1], [2], [3], [4], [5], [6], [7]. This phenomenon, also known as the Glagov phenomenon, is characterized by an outward enlargement of the vessel wall (positive remodeling) without compromise of the lumen area during the early stages of atherosclerosis [2].…”

Newer Concepts Regarding Adults With Coronary Artery Aneurysms

“…According to the Glagov theory, the outer diameter of the coronary arteries dilates in the early phases of atherosclerosis, when plaque deposition leads to positive remodeling with preservation of the vessel lumen. 4 Such positive remodeling probably does not allow for a dilatation of the coronary artery Ͼ50% of the previous normal diameter.…”