Cardiac magnetic resonance perfusion imaging for the functional assessment of coronary artery disease: a comparison with coronary angiography and fractional flow reserve.

AIMS: Cardiac magnetic resonance perfusion imaging (CMRI) is a promising technique for non-invasive measurement of myocardial perfusion reserve. Fractional flow reserve (FFR) is an established invasive method for functional assessment of coronary artery disease (CAD). To prospectively assess the diagnostic value of CMRI for the detection of haemodynamically significant coronary lesions, compared with coronary angiography (CA) and FFR. METHODS AND RESULTS: Forty-three patients with suspected or known CAD underwent CA, CMRI, and FFR measurement. First pass magnetic resonance perfusion examination was performed during hyperaemia (140 microg/kg/min adenosine over 6 min) and at rest. One hundred and twenty-nine perfusion territories were assessed by semi-quantitative evaluation of signal intensity-time curves using the myocardial perfusion reserve index (MPRI) [upslope(stress(corrected))/upslope(rest(corrected))]. Perfusion territories were categorized as normal (coronary stenosis < or = 50%), intermediate (stenosis > 50% and FFR > 0.75), or severe (stenosis > 50% and FFR < or = 0.75 or total occlusion). MPRI values (+/-SD) were significantly different between the three categories [normal, 2.2 +/- 0.5 vs. intermediate, 1.8 +/- 0.5 (P = 0.005) and intermediate vs. severe, 1.2 +/- 0.3 (P < 0.001)]. An MPRI cut-off value of 1.5 (derived from receiver operating characteristics analysis) distinguished haemodynamically relevant (severe) from non-relevant (normal and intermediate) stenoses with a sensitivity of 88% (CI 74-100%) and a specificity of 90% (CI 84-96%). CONCLUSION: In contrast to earlier studies that compared CMRI with morphological examination (CA) alone, the present study compared CMRI with CA plus a standard invasive functional assessment (FFR) and demonstrated that CMRI is able to distinguish haemodynamically relevant from non-relevant coronary lesions with a high sensitivity and specificity and may therefore contribute to clinical decision-making.

Sirolimus-eluting stent implantation and beta-irradiation for the treatment of in-stent restenotic lesions: comparison of underlying mechanisms of acute gain and late loss as assessed by volumetric intravascular ultrasound.

BACKGROUND: The aim of the study was to compare the angioplasty mechanisms of drug (sirolimus)-eluting stent (DES) implantation and vascular brachytherapy (VBT) for the treatment of in-stent restenosis (ISR) as assessed by intravascular ultrasound (IVUS). METHODS: We performed IVUS in 53 patients (28 DES, 25 VBT) before and after angioplasty of ISR and at 6-month follow-up. Cross-sectional areas of the external elastic membrane, the stent, and the lumen were measured. Plaque + media, peristent plaque, and intimal hyperplasia areas were calculated, respectively. RESULTS: Clinical and IVUS baseline characteristics did not differ between groups at baseline. After the index procedure, the lumen at the stent site was smaller in the DES group (DES 6.7 +/- 2.0 mm2 vs VBT 7.5 +/- 2.2 mm2, P = .042). Because of less intimal hyperplasia (DES 0.2 +/- 0.5 mm2 vs VBT 0.7 +/- 0.7 mm2, P = .043), the lumen dimensions revealed no difference between groups at follow-up (DES 6.5 +/- 2.3 mm2 vs VBT 6.8 +/- 2.2 mm2, P = .374). At the reference site, the index procedure led to a similar increase of plaque + media (DES 0.9 +/- 0.9 mm2 vs VBT 0.6 +/- 1.2 mm2, P = .150). At follow-up, the plaque + media was significantly smaller in the DES group (DES 8.0 +/- 6.6 mm2 vs VBT 9.9 +/- 7.8 mm2, P = .013). CONCLUSIONS: Drug-eluting stent for the treatment of ISR more effectively inhibits neointima formation when compared with VBT. Yet insufficient stent expansion might be a reason for device failure and should be avoided. At the reference site, lumen loss by an increased plaque burden, as has been well recognized following VBT, is not present with DES.

Comparison of acute and long-term results and underlying mechanisms from sirolimus-eluting stent implantation for the treatment of in-stent restenosis and recurrent in-stent restenosis in patients in whom intracoronary radiation failed as assessed by intravascular ultrasound.

In-stent restenosis (ISR), especially after vascular brachytherapy, is a therapeutic challenge. Sirolimus-eluting stent implantation is a promising new option for the treatment of patients with ISR. The efficacy of sirolimus-eluting stent implantation for the treatment of patients with their first episodes of ISR and with recurrent ISR due to the failure of vascular brachytherapy was compared using intravascular ultrasound imaging.