Effect of Adjuvant Balloon Inflation on Infarct Artery Flow after Primary Stenting

BACKGROUND AND OBJECTIVES: Slow flow or no-reflow during the primary angioplasty is associated with a poor prognosis. The impact of adjuvant balloon inflation on infarct artery flow after successful primary stenting has not yet been studied. Therefore, we investigated the effect of adjuvant balloon inflation on infarct related artery flow after successful stenting in patients with acute myocardial infarction. SUBJECTS AND METHODS: The changes in infarct artery flow before and after adjuvant balloon inflation were assessed in 46 patients with a first episode of acute myocardial infarction (pain duration > 12 hr) who underwent adjuvant balloon inflation after successful primary stenting. Infarct artery flow was evaluated by corrected TIMI frame count (CTFC). RESULTS: After adjuvant balloon inflation, 20 patients (43%) showed a slower flow. The minimal lumen diameter became greater (3.0 > 0.5 mm vs. 3.2 > 0.5 mm, p=0.002) and the residual stenosis lessened (12.2 > 9.6% vs. 6.4 > 8.1%, p 11.5 frames vs. 26.9 > 20.5 frames, p=0.005). On multivariate analysis, only pre-adjuvant balloon CTFC was a predictor of a slower flow after adjuvant balloon inflation (odds ratio 1.148, 95% CI:1.014-1.301). CONCLUSION: Adjuvant balloon inflation after successful primary stenting reduced residual stenosis but deteriorated the infarct artery flow. Further studies are required to define the clinical impact of the positive and negative effects of adjuvant balloon inflation.

Morphological Characteristics of Intimal Hyperplasia in Stented Coronary Arteries Assessed with Intravascular Ultrasound

BACKGROUND: Intravascular ultrasound(IVUS) provides high resolution cross-sectional images of the vessels and permits the quantiative and qualitative assessment of coronary artery disease. Stent is a figid endovascular lattice that effectively prevents elastic recoil at treated sites, but in-stent restenois is a major limitation. The purpose of thecurrent study is to assess the contribution of neointimal hyperplasia for in-stent restenosis and the distribution and morphological characteristics of neointimal hyperplasia in deployed stents. METHODS: Thirty patients(male 25 & female 5;31 leions) deployed with intracoronary stents underwent intravascular ultrasound imaging at follow-up at least 4 months after stenting ([mean+/-SD] 8.3+/-2.9 months). RESULTS: 1) In-stent restenosis occurered in 15 lesions out of 31 lesions at follow-up coronary angiography. There was no difference in clinical characteristics between the restenotic and the non-restenotic groups. 2) There was no difference in angiographic profiles between two groups. Deployed stents were as follows ; 16 Palmaz-Schatz(P-S) stents, 12 Gianturco-Roubin(G-R) stents, 2 Cordis stents, and I Microstent II. Average diameter of stents in the restenotic and the non-restenotic groups were 3.07+/-0.26mm and 3.16+/-0.30mm, respectively(p=0.38). 3) There was no difference of stent cross-sectional areas(CSA) between the non-restenotic and the restenotic groups(p=0.476), but luminal CSA of the restenotic group was significantly smaller than that of the non-restenotic group(p=0.006). 4) In the restenotic group, there were no differences of the maximal and the minimal diameters of stents, and the mean CSAs of stents smong proxiaml, mid and distal segments. But the mean CSA of neointimal hyperplasia at the mid segment was larger than that at the distal segment(p<0.05). There was a tendency thatthe mean CSA of neointimal hyperplasia at the mid segment was larger than that at the proximal segment(p=0.187). These findings were the same in the non-restenotic group. 5) In the restenotic group deployed with P-S stents, there were no differences of the maximal and the minimal diameters of stents, and the mean cross-sectional areas(CSA) of stents between each segment. But, the mean CSA of neointimal hyperplasia at the mid segment was larger than that at the distal segment(p<0.005) and there was a tendency that the mean CSA of neointimal hyperplasia at the mid segment was larger than that at the proximal segment(p=0.354). 6) In the morphology of neointimal hyperplasia of the restenotic group, eccentric form(77%) was more common than concentric form(22%). Neointimal hyperplasia occurred in focal or diffuse patterns(7 versus 8 cases). CONCLUSIONS: In-stent restenosis resulted from neointimal hyperplasia which almost mainly occurred eccentrically at the mid segment of stents and in focal or diffuse patterns. Intravascular ultrasound imaging was a useful method for recognition of distribution and morphological characteristics of neointimal hyperplasia at follow-up of deployed stents.