Vascular Reactivit After Balloon Angioplasty in an Atherosclerotic Rabbit

Alterations in vessel wall reactivity (VR) at or adjacent to the dilation site after balloon angioplasty (BA) may vary according to the inflation protocol and the time after angioplasty and may influence outcome. In 64 atherosclerotic rabbit femoral arteries, we evaluated VR after BA with intravenous ergonovine (ERGO) (40,ug/min for 5 minutes) and intra-arterial nitroglycerin (NTG) (2,500,ug single bolus) 24-72 hours and 28 days after BA. Comparisons were made with atherosclerotic, nonangioplastied, age-matched controls. BA was standardized to three 1-minute inflations, each 1 minute apart. For each balloon size, 2.5- (appropriate size) or 3.0-mm (oversized) vessels were allocated to either 5 or 10 atm inflation pressure. For the analysis, four groups were compared: Group 1, 3.0/5; group 2, 3.0/10; group 3, 2.5/5, and group 4, 2.5 mm/10 atm. Angiographic diameters were measured at, proximal, and distal to the lesion at baseline, 10 minutes after ERGO, and 5 minutes after NTG. Angiograms were measured with electronic calipers by two blinded observers. All segments of control vessels vasoconstricted to ERGO and vasodilated to NTG (p<0.05 versus baseline), indicating a normal response. At 24-72 hours after dilatation, the angioplasty sites for all inflation pressure/balloon size combinations were not responsive to either ERGO or NTG. All segments distal to the dilatatio