Long genuine coronary artery lesions treated with stiff tubular or flexible coiled stents. A randomized angiographic follow-up study

Cardiac Magnetic Resonance Imaging used for Evaluation of Adipose-Derived Stromal Cell Therapy in Patients with Chronic Ischemic Heart Disease

Adipose-derived stromal cell (ASC) therapy is currently investigated as a new treatment option for patients with ischemic heart disease (IHD). The aim of this study was to evaluate the effect of ASC therapy in patients with chronic IHD measuring myocardial perfusion and cardiac function using cardiac magnetic resonance imaging (CMRI). Patients were included in MyStromalCell trial, a phase II, randomized, double-blinded, placebo-controlled study investigated the effect of ASCs in patients with chronic IHD with preserved left ventricular ejection fraction (LVEF). In total, 41 of 60 patients underwent cine, late enhancement, rest and stress imaging with CMRI. There was a non-significant difference between stress and rest values in maximal signal intensity, a measure of myocardial perfusion, from baseline to follow-up comparing placebo with ASC group (–52.52 ± 88.61 and 3.05 ± 63.17, p = 0.061, respectively). LVEF, myocardial mass, stroke volume, left ventricle end-diastolic volume and end-systolic volume changed non-significantly (–0.5 ± 4.7%, –3.5 ± 13.1 g, –0.7 ± 8.6 mL, 1.9 ± 25.1 mL and 2.6 ± 16.5 mL, respectively) in the placebo group and in the ASC group (0.7 ± 8.6%, 0.9 ± 10.8 g, –0.3 ± 26.1 mL, –3.0 ± 31.5 mL and –2.7 ± 20.4 mL, respectively) from baseline to 6 months follow-up. The amount of scar tissue was unchanged in the placebo group by 0.0 ± 1.6 g, p = 1.0 and in the ASC group with –0.3 ± 2.3 g, p = 0.540. There was no difference between the groups. There was a non-significant trend toward increased myocardial perfusion but no significant changes in functional parameters or amount of scar tissue in patients treated with ASCs compared with patients allocated into the placebo group.

Quantification of myocardial perfusion using cardiac magnetic resonance imaging correlates significantly to rubidium-82 positron emission tomography in patients with severe coronary artery disease: a preliminary study

INTRODUCTION

Aim was to compare absolute myocardial perfusion using cardiac magnetic resonance imaging (CMRI) based on Tikhonov's procedure of deconvolution and rubidium-82 positron emission tomography (Rb-82 PET).

MATERIALS AND METHODS

Fourteen patients with coronary artery stenosis underwent rest and adenosine stress imaging by 1.5-Tesla MR Scanner and a mCT/PET 64-slice Scanner. CMRI were analyzed based on Tikhonov's procedure of deconvolution without specifying an explicit compartment model using our own software. PET images were analyzed using standard clinical software. CMRI and PET data was compared with Spearman's rho and Bland-Altman analysis.

RESULTS

CMRI results were strongly and significantly correlated with PET results for the absolute global myocardial perfusion differences (r=0.805, p=0.001) and for global myocardial perfusion reserve (MPR) (r=0.886, p<0.001). At vessel territorial level, CMRI results were also significantly correlated with absolute PET myocardial perfusion differences (r=0.737, p<0.001) and MPR (r=0.818, p<0.001). Each vessel territory had similar strong correlation for absolute myocardial perfusion differences (right coronary artery (RCA): r=0.787, p=0.001; left anterior descending artery (LAD): r=0.796, p=0.001; left circumflex artery (LCX): r=0.880, p<0.001) and for MPR (RCA: r=0.895, p<0.001; LAD: r=0.886, p<0.001; LCX: r=0.886, p<0.001).

CONCLUSION

On a global and vessel territorial basis, CMRI-measured absolute myocardial perfusion differences and MPR were strongly and significantly correlated with the Rb-82 PET findings.

Residual Stenosis Poststenting and Subsequent Decrease in the Proximal Reference Diameter Are Correlated:Excessive Axial Wall Stress Is a Plausible Explanation

PURPOSE

To test the hypothesis that edge restenosis in stented lesions might be due to an increase in axial wall stress in the adjacent proximal vessel segment by examining whether the proximal reference diameters of conventionally stented lesions are reduced at follow-up and whether this reduction depends on the degree of residual stenosis poststenting.

METHODS

The literature published in the past 5 years dealing with restenosis following implantation of standard stents was screened for the availability of (1) reference vessel diameters poststenting, (2) mean residual stenosis poststenting, and (3) mean reference vessel diameters at follow-up in the same patients or groups of patients. Data collected from 11 publications were pooled and used to compute the change in reference segment diameter over time. These differences were compared to the residual stenosis poststenting by nonlinear regression.

RESULTS

The reduction in the mean reference diameters over time and the mean residual stenosis poststenting appear to be strongly correlated (r2 = 0.838), which supports the idea that the evolution of a stenosis adjacent to a stent margin depends on the severity of the residual stenosis.

CONCLUSIONS

This finding indicates that edge restenosis might be due to excessive axial wall stress. It may also explain, at least partly, why edge restenosis is observed with catheter-based brachytherapy and radioactive or drug-eluting stents.