[Association between progression of untreated coronary lesions and in-stent restenosis]

Progression of coronary artery disease is only incompletely understood regarding de-novo stenoses as well as in-stent restenoses (ISR) indicative of accelerated atherosclerosis. The objective of the present angiographic study was to prove an association between target lesion ISR and progression of primarily untreated coronary lesions.

A total of 179 high-grade native coronary stenoses (mean diameter stenosis 68+/-16 %) of 131 patients were treated by stent implantation. Additional 101 lesions remained untreated because of their moderate to intermediate diameter stenoses (>30 %). Quantitative coronary angiographic analysis was performed 6+/-2 months later to evaluate ISR (diameter stenosis > 50 %), coronary progression (>20 % increase in diameter stenosis) and regression (>20 % decrease), respectively. Angiographic, procedural and clinical characteristics were assessed for a possible association with ISR and/or coronary progression and regression, respectively.

ISR was seen in 70 of 179 (39 %) stented target lesions. Presence of diabetes mellitus (p = 0.04) and cumulative duration of inflations (p = 0.01) as procedural determinant were predictive for ISR. Significant progression was found in ten of 101 (10 %) primarily untreated lesions. Progression of previously normal segments or regression were not seen. Progression of native plaques was associated with ISR presence in nine cases and with ISR absence in only one case (p = 0.01). Of note, smoking (p = 0.02) turned out to be predictive for plaque progression, whereas medication and procedural/angiographic parameters were not.

The findings of the present pilot study demonstrate target lesion ISR associated with progression of other primarily untreated lesions and thereby suggest that both atherosclerosis types share common systemic pathogenetic mechanisms. With presence of ISR, coronary angiography should also include primarily untreated arteries, especially in case of preexisting plaques.