Shinichiro Ikuta

Quantitative myocardial perfusion analysis using multi-row detector CT in acute myocardial infarction

Objective To assess the feasibility of quantitative myocardial perfusion imaging (MPI) in acute myocardial infarction (AMI), using multi-row detector CT (MDCT) with a model-based deconvolution method. Design, setting, patients and interventions Fifteen normal subjects with normal coronary arteries and 26 patients with AMI after reperfusion therapy underwent MPI with MDCT. Perfusion parameters: tissue blood flow (TBF), tissue blood volume (TBV) and mean transit time (MTT) were obtained and compared with clinical parameters, angiography and single-photon emission CT (SPECT) data. Furthermore, the MPI data were compared with data from myocardial magnetic resonance (MR) in 10 subjects. Results The TBF and TBV of infarcted myocardium were significantly lower than those of non-infarcted areas (TBF, 51.96±19.42 vs 108.84±13.29 ml/100 g/min, p<0.01; TBV, 4.47±2.23 vs 9.79±2.58 ml/100 g, p<0.01). The MTT of infarcted areas did not differ from that of non-infarcted areas. The defect areas on TBV colour maps were significantly associated with peak creatine kinase level, QRS score and SPECT defect score. The ratio of TBF or TBV in the epicardial to endocardial side was significantly higher in infarct myocardium with good collateral circulation than in myocardium with poor/no collateral circulation (p<0.01 for both). The TBF measurements with CT- and MR-MPI were in good agreement by linear regression analysis (R=0.55, p<0.01). Conclusions This study demonstrated that MDCT perfusion imaging with deconvolution analysis could quantitatively detect myocardial perfusion abnormalities in patients with AMI and may provide the basis for the non-invasive and quantitative assessment of myocardial infarction.

Difference in statin effects on neointimal coverage after implantation of drug-eluting stents.

ObjectiveThis study was carried out to examine the difference in effects between rosuvastatin and pravastatin on neointimal formation after the placement of a drug-eluting stent (DES). Materials and methodsForty patients who underwent placement of a DES in our hospital were prospectively randomized to receive rosuvastatin (n=20) or pravastatin (n=20), and analyzed by optical coherence tomography at the chronic stage. The main outcome measure was comparison of neointimal coverage analyzed at a strut level. ResultsA significant reduction in total cholesterol, low-density lipoprotein, and white blood cell count was observed during the study in the rosuvastatin group (total cholesterol, from 4.82±0.90 to 4.43±0.77 mmol/l, P=0.038; low-density lipoprotein, from 2.85±0.76 to 2.34±0.57 mmol/l, P=0.006; white blood cell count, from 5810±1399 to 5355±1257/µl, P=0.048), but not in the pravastatin group. Although not statistically significant, C-reactive protein was lower in the rosuvastatin than in the pravastatin group at the chronic stage (1.14±1.21 vs. 7.67±13.67 mg/l, P=0.051). Malapposed and uncovered struts were significantly less frequent in the rosuvastatin group than in the pravastatin group (malapposed, 0.06 vs. 0.60%, P<0.001; uncovered, 6.49 vs. 11.29%, P<0.001). The difference in uncovered struts was maintained even when stent types were analyzed separately (everolimus-eluting stent, 4.81 vs. 6.21%, P=0.007; sirolimus-eluting stent, 14.40 vs. 20.86%, P<0.001). Comparison of neointimal thickness between the rosuvastatin and the pravastatin groups showed inconsistent results depending on the stent types analyzed. ConclusionCompared with pravastatin, the use of rosuvastatin resulted in lower frequency of uncovered and malapposed struts after the placement of a DES, which might be mediated through improved inflammatory and lipid profiles.

Clinical utility of low-pressure implantation of drug-eluting stent into very small vessels

BACKGROUND Although drug-eluting stents (DES) reduce restenosis, the best strategy for DES implantation in small vessels has not been established. PURPOSE We investigated the clinical usefulness of low-pressure implantation of a 2.5-mm DES for small vessels less than 2.5mm in diameter. METHODS In 118 patients, a 2.5-mm DES was implanted for small vessels less than 2.5mm in diameter between 2007 and 2009 in our hospital. The patients were divided into two groups by initial deployment pressure: low-pressure (LP; n=46) and nominal-pressure (NP; n=72). RESULTS Patients with impaired glucose tolerance were more frequent (p=0.02) and the target vessel diameter was significantly smaller (p=0.01) in the LP group than in the NP group. A smaller minimum lumen diameter (MLD) was obtained (LP: 2.22±0.27mm vs. NP: 2.34±0.26mm, p=0.02) after DES implantation with a smaller balloon-to-artery ratio (p=0.03) in the LP group. However, at mid-term follow-up (7.7±3.9 months), MLD (p=0.55) and the binary restenosis rate (LP: 2.6% vs. NP: 11.1%, p=0.12) were not significantly different between the LP and NP groups. Furthermore, by Kaplan-Meier analysis, the incidence of major adverse cardiac events was not different between the groups during the long-term follow-up (32.4±8.6 months). CONCLUSION The present study indicates that low-pressure implantation of 2.5-mm DES for very small vessels may be feasible with regard to short- and long-term clinical outcomes.

Backyards of Chronic Total Occlusion Scenery Revealed Through Angioscope

Chronic total occlusion (CTO) remains a challenging lesion subset in percutaneous coronary intervention and endovascular treatment because of low initial procedural success rates and high rates of restenosis at the chronic stage. There are only a few reports of human pathologic specimens of CTO in the literature.1 Angioscopy has been reported to be useful for the direct visualization of thrombus and allows for characterization of the vessel wall from inside,2 but we cannot observe the distal side of CTO in coronary arteries. Here we report an evaluation of the distal side of CTO of the superficial femoral artery (SFA) via a retrograde approach with angioscopy. ### Case 1 A 71-year–old man with hypertension, dyslipidemia, and type 2 diabetes mellitus noticed intermittent claudication in both legs in 2003. He received endovascular treatment of the left iliac artery in 2003 and that of the right iliac artery in 2008. The symptom, however, recurred in 2010, and medical treatment failed to improve it. He received another endovascular treatment for the right SFA. Control angiography revealed a short total occlusion in the right SFA (Figure 1A and Movies I and II in the …