Functional significance of recruitable collaterals during temporary coronary occlusion evaluated by 99mTc-sestamibi single-photon emission computerized tomography

AbstractOBJECTIVESThe present study evaluated the impact of recruitable collaterals on regional myocardial perfusion measured by 99mtechnetium (Tc)-sestamibi single-photon emission computerized tomography (SPECT) during temporary coronary occlusion and related these estimates to the coronary wedge pressure and electrocardiographic (ECG) ST-segment changes.BACKGROUNDClinical variables (angina and ECG changes) and intracoronary flow and pressure recordings have indicated a protective role of recruitable collaterals on myocardial perfusion during percutaneous transluminal coronary angioplasty (PTCA).METHODSThirty patients (mean age 55 years, SD 9; 20 men) with stable angina pectoris and proximal nonoccluding single-vessel left anterior descending coronary artery (LAD)-stenosis scheduled for PTCA were included. Visualization of recruitable collaterals by ipsilateral and contralateral contrast injection, registration of coronary wedge pressure and injection of 99mTc-sestamibi during 90-s LAD occlusions were undertaken. A rest perfusion study was performed within four days before PTCA. As an estimate of the severity of regional hypoperfusion during occlusion, an occlusion/rest count ratio was calculated (mean defect pixel count during occlusion divided by mean pixel count in identical regions at rest).RESULTSThe scintigraphic occlusion/rest count ratio was higher in patients with recruitable collaterals (n = 16), 67 ± 11%, compared to patients without collaterals (n = 14), 60 ± 6% (p < 0.05). The occlusion/rest count ratio correlated with the coronary wedge pressure (R2= 0.34; p < 0.001). The occlusion/rest count ratio was lower, 61 ± 6%, in patients with ST-segment elevation (n = 23) versus 74 ± 9% in patients without ST-segment elevation (n = 7) (p < 0.0001).CONCLUSIONSUsing 99mTc-sestamibi SPECT imaging during brief episodes of coronary occlusion, the severity of regional myocardial hypoperfusion was reduced by the presence of recruitable collaterals in a selected patient population with proximal LAD stenoses. Our results demonstrate a protective effect of recruitable collaterals on myocardial perfusion during temporary coronary occlusion

Increased Rate of Stent Thrombosis and Target Lesion Revascularization After Filter Protection in Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction 15-Month Follow-Up of the DEDICATION (Drug Elution and Distal Protection in ST Elevation Myocardial Infarction) Trial

ObjectivesThe purpose of this study was to evaluate the long-term effects of distal protection during percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI).BackgroundThe use of distal filter protection during primary PCI increases procedure complexity and may influence lesion treatment and stent implantation.MethodsThe STEMI patients were assigned to distal protection (DP) (n = 312) or conventional treatment (CT) (n = 314). Clinical follow-up was performed after 1, 6, and 15 months, and angiographic follow-up after 8 months. All target lesion revascularizations (TLRs) were clinically driven. We report the pre-specified end points of stent thrombosis according to the criteria of the Academic Research Consortium, TLR, and reinfarction after 15 months.ResultsThe total number of stent thrombosis was 11 in the DP group and 4 in the CT group (p = 0.06). The rate of definite stent thrombosis was significantly increased in the DP group as compared with the CT group, with 9 cases versus 1 (p = 0.01). Clinically driven TLRs (31 patients vs. 18 patients, p = 0.05) and clinically driven target vessel revascularizations (37 patients vs. 22 patients, p = 0.04) were more frequent in the DP group.ConclusionsIn primary PCI for STEMI, the routine use of DP increased the incidence of stent thrombosis and clinically driven target lesion/vessel revascularization during 15 months of follow-up. (Drug Elution and Distal Protection in ST Elevation Myocardial Infarction Trial [DEDICATION]; NCT00192868

Reproducibility of Shin's method for necrotic core and calcium content in atherosclerotic coronary lesions treated with bioresorbable everolimus-eluting vascular scaffolds using volumetric intravascular ultrasound radiofrequency-based analysis

Although Virtual Histology intravascular ultrasound (VH-IVUS) is increasingly used in clinical research, the reproducibility of plaque composition remains unexplored in significant coronary artery and stented lesions. The purpose of this study was to assess the reproducibility of necrotic core and calcium content in atherosclerotic coronary lesions that were treated with a bioresorbable everolimus-eluting vascular scaffold (BVS) using a new measurement method (Shin's method) by VH-IVUS. Eight patients treated with a BVS (Abbott Vascular, Santa Clara, CA, USA) were analyzed with serial VH-IVUS assessments, i.e., pre- and post-stenting, and at 6 months and 2 years follow-up. A total of 32 coronary segments were imaged to evaluate the reproducibility of volumetric VH-IVUS measurements. In Shin's method, contours are drawn around the IVUS catheter (instead of the lumen) and vessel. Overall, in the imaged coronary segment, for necrotic core and dense calcium volumes, the relative intra-observer differences were 0.30 ± 0.22, 0.19 ± 0.16% for observer 1 and 0.45 ± 0.41, 0.36 ± 0.47% for observer 2, respectively. The interobserver relative differences of necrotic core and dense calcium volumes were 0.51 ± 0.79 and 0.56 ± 1.01%, respectively. The present study demonstrates a good reproducibility for both, intra-observer and interobserver measurements using Shin's method. This method is suitable for the measurement of necrotic core and dense calcium using VH-IVUS in longitudinal studies, especially studies on bioresorbable scaffolds, because the degradation process will be fully captured independently of the location of the struts and their greyscale appearance