Spontaneous regression of restenosis: an angiographic study

This study was designed to examine the possibility that spontaneous regression in stenosis severity occurs over time in patients with restenosis after percutaneous transluminal coronary angioplasty.

The underlying mechanisms of restenosis are intimal hyperplasia and smooth muscle cell proliferation in response to vascular injury. We hypothesized that the initial hyperplastic response is followed by dynamic remodeling and eventual spontaneous regression, leading to stabilization or a reduction in stenosis severity.

A total of 136 patients participated in a trial to evaluate the efficacy of fish oil versus placebo in preventing restenosis after angioplasty. One hundred thirteen patients completed this study with angiographic follow-up, of whom 56 had restenosis. Of these, 19 were asymptomatic and did not undergo repeat revascularization; 15 consented in a separate study to undergo repeat angiography, which was performed 6 to 25 months later to assess the possibility of regression.

There was a significant mean (+/- SD) decrease in lesion severity from 66.9 +/- 8.7% to 47.5 +/- 9.0% (p < 0.0001) and a significant mean increase in minimal lumen diameter from 0.91 +/- 0.31 mm to 1.44 +/- 0.35 mm (p < 0.0001). No patient showed progression of stenosis, but regression of restenosis, defined as a decrease in minimal lumen diameter > or = 0.2 mm, was noted in 12 of the patients.

Although all 15 study patients were asymptomatic, similar changes may occur in symptomatic patients. A trial of medical therapy may be appropriate in asymptomatic or mildly symptomatic patients before further interventions. This strategy would avoid unnecessary invasive procedures, prevent a "restenosis cycle" and result in significant cost savings.