[Percutaneous coronary intervention and stent thrombosis].

Despite improved stent implantation technologies and effective antiplatelet regimens, stent thrombosis has been one of the most important problem in percutaneous coronary intervention. Stent thrombosis is a rare but usually catastrophic event, frequently associated with large MI or death. Stent thrombosis is generally categorized according to the timing of the event as early (0 to 30 days), late (31 days to 1 year), very late (> 1 year). Late and very late stent thrombosis after stent implantation has not yet been adequately characterized, mainly because of its low incidence. And the optimal duration of dual antiplatelet therapy remains uncertain for patients receiving drug-eluting stents.

Early and Mid-Term Vascular Responses to Optical Coherence Tomography-Guided Everolimus-Eluting Stent Implantation in Stable Coronary Artery Disease.

BACKGROUND: Analysis of pooled clinical data has shown the safety of 3 months of dual antiplatelet therapy with everolimus-eluting cobalt-chromium stents (Co-Cr EESs). This study evaluated early and mid-term vascular responses to Co-Cr EESs in patients with stable coronary artery disease. METHODS: The Multicenter Comparison of Early and Late Vascular Responses to Everolimus-Eluting Cobalt-Chromium Stent and Platelet Aggregation Studies in Patients With Stable Angina Managed as Elective Case (MECHANISM-Elective) study (NCT02014818) is a multicenter optical coherence tomography (OCT) registry. Enrolled patients were evaluated by OCT immediately after everolimus-eluting stent implantation were prospectively allocated to 1 month (n = 50) or 3 months (n = 50) OCT follow-up and then received a 12-month OCT evaluation. The incidences of intrastent thrombus (IS-Th) and irregular protrusion (IRP) were also assessed. RESULTS: The percentage of uncovered struts was 6.4% ± 10.3% at 1 month (P < 0.001 vs. postprocedure) and 0.5% ± 0.9% at 12 months (P < 0.001 vs. 1 month). The corresponding values in the 3-month cohort were 2.0% ± 2.5% (P < 0.001 vs. postprocedure) and 0.5% ± 1.5% (P < 0.001 vs. 3 months). The incidence of IS-Th was 32.7% at 1 month, 5.4% at 3 months, and 2.0% at 12 months. IRP was observed in 21.8% of patients post-EES but had totally resolved at 1, 3, and 12 months. CONCLUSION: Early and mid-term vascular reactions after Co-Cr EES implantation in stable patients with coronary artery disease in the MECHANISM-Elective included dynamic resolution of IS-Th and IRP and rapid decrease in uncovered struts. Thus, EES may allow shortening of dual antiplatelet therapy duration less than 3 months in this patient subset.

A New Contrast Enhancement Protocol for Subtraction Coronary Computed Tomography Requiring a Short Breath-Holding Time.

RATIONALE AND OBJECTIVES: We have developed a new contrast enhancement protocol for subtraction coronary computed tomography (SCCTA) requiring a short breath-holding time. In the protocol, test and main boluses were sequentially and automatically injected, and correct timings for pre-contrast and contrast-enhanced scans for main bolus were automatically determined only by the test bolus tracking. Combined with a fixed short main bolus injection for 7 seconds, the breath-holding time was shortened as possible. The purpose of this study was to evaluate whether use of this new protocol produced adequate quality images, taking into account calcified lesions and in-stent lumens. MATERIALS AND METHODS: Patients (n = 127) with calcium scores of >400 Agatston units or a history of stent placement were enrolled. Breath-holding times were recorded, and image quality was visually evaluated by two observers. RESULTS: The mean ± standard deviation breath-holding time was 13.2 ± 0.6 seconds. The mean ± SD computed tomography (CT) number of coronary arteries for the pre-contrast scan was sufficiently low [99.2 ± 32.2 Hounsfield units (HU)] and, simultaneously, that for SCCTA was 367.0 ± 77.2 HU. The rate of segments evaluated as unreadable was sufficiently low (3.8%). CONCLUSIONS: Use of the SCCTA protocol was efficient and allowed for a shorter breath-holding time and adequate diagnostic accuracy of SCCTA images, including images of calcified and stent implantation segments.

Visualization of collateral channels with coronary computed tomography angiography for the retrograde approach in percutaneous coronary intervention for chronic total occlusion.

BACKGROUND: There have been no reports about the diagnostic ability of coronary computed tomography angiography (CTA) in evaluating collateral channels used for retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI). OBJECTIVE: We investigated the ability and diagnostic accuracy of coronary CTA compared with invasive coronary angiography to detect collaterals used in retrograde CTO PCI and to compared the success rates for wire crossing between collaterals that are detectable and not detectable in coronary CTA. METHODS: We retrospectively reviewed data from 43 patients (55 collaterals) who underwent coronary CTA and PCI for CTO with the retrograde approach. We compared the ability of coronary CTA to visualize collaterals to invasive coronary angiography and evaluated the rates of successful wire crossing between CTA-visible and invisible collaterals. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of coronary CTA for detecting collaterals which were used for the retrograde approach was 100.0%, 50.0%, 65.9%, 100.0%, and 74.5%, respectively. Guidewire collateral crossing was more successful in CT-visible collaterals than those not detectable in CT (74.1% vs. 46.4%, p = 0.034). There were fewer collateral vessel injuries in CTA-visible collaterals (11.1% vs. 32.1%, p = 0.041). CONCLUSION: Coronary CTA provides good visualization of collaterals used in retrograde CTO PCI. For retrograde guidewire crossing, a higher success rate with fewer complications was observed in CTA-visible collaterals than in those not detectable in coronary CTA.

Non-coronary cardiac findings and pitfalls in coronary computed tomography angiography.

Non-coronary incidental findings are not rare. Kirsch et al found 67% non-coronary abnormalities with coronary computed tomography angiography (CCTA). Radiologists are expected to identify the extracoronary, intra- and para-cardiac anatomical structures and distinguish them from pathologic processes in CCTA. We have reviewed 2000 CCTA studies done at our institution with 64-MDCT. This pictorial essay presents case studies of non-atherosclerotic cardiovascular findings to recognize cardiac anatomic structures and how to distinguish them from pathologic processes. Correct interpretation of benign, clinically insignificant findings is crucial to avoid unnecessary additional imaging tests.