Absence of detectable delayed elastic recoil 24 hours after percutaneous transluminal coronary angioplasty

During percutaneous transluminal coronary angioplasty (PTCA), part of the constraints developed by the inflated balloon beyond the value needed for splitting or fracturing the atherosclerotic plaque are absorbed by the elastic components of the arterial wall to be restored after balloon deflation. The return of these elastic components to their unstrained dimensions (elastic recoil) results in the loss of a significant part of the theoretical maximal gain in lumen diameter achieved during balloon inflation. Although the contribution of elastic recoil to the residual stenosis of coronary segments immediately after PTCA appears well established,^1-3 controversy remains regarding the possible contribution of some progressive or delayed recoil to the restenosis observed in 17 to 47% of patients several weeks or months after PTCA.⁴ Morphologic studies of restenosis sites after PTCA have suggested that chronic recoil could be a mechanism of late luminal narrowing, independent of intimai fibrous proliferation.^4-5 However, quantitative angiographic studies in small populations did not show a further reduction in minimal lumen diameter of dilated coronary segments during the first 24 hours after successful PTCA.^1,2 The present study was designed to evaluate in a large group of patients whether gradual or delayed elastic recoil could result in a further luminal narrowing during the first 24 hours after successful PTCA. Alt angiographic data were obtained under standardized conditions, including local infusion of nitrates, to minimize the influence of vasomotor tone.