Qualitative and quantitative evaluation of dynamic changes in non-culprit coronary atherosclerotic lesion morphology: a longitudinal OCT study.

AIMS: There is limited in vivo evidence regarding the temporal evolution of non-culprit coronary plaque morphology. We aimed to evaluate changes in non-culprit plaque morphology over time by optical coherence tomography (OCT). METHODS AND RESULTS: Seventy-two (72) patients with 257 non-culprit segments with serial OCT studies were analysed. Non-culprit 5 mm-long coronary segments from the same imaged region were matched between baseline and follow-up. OCT plaque characterisation including automated attenuation analysis was performed, and changes over a median follow-up of 6.2 months were evaluated. On segment level, lumen area decreased from baseline to follow-up, whereas fibrous cap thickness increased. Similarly, plaque attenuation indices at follow-up were significantly decreased. Minimal cap thickness per patient did not change. In 68.5% of segments, plaque morphology did not change. Favourable change was observed in 18.4% of segments and unfavourable in 12.9%. There were no robust clinical predictors of change in plaque morphology. Attenuation analysis supported the qualitative characterisation, showing significantly different attenuation between different plaque types. CONCLUSIONS: In non-culprit coronary segments of patients with coronary artery disease under standard medical therapy, segment-level but not patient-level minimum fibrous cap thickness increases over time, with observations of both favourable and unfavourable changes in individual segments.

Safety of optical coherence tomography in daily practice: a comparison with intravascular ultrasound.

AIMS: Previous studies have reported the safety and feasibility of both time-domain optical coherence tomography (TD-OCT) and Fourier-domain OCT (FD-OCT) in highly selected patients and clinical settings. However, the generalizability of these data is limited, and data in unselected patient populations reflecting a routine cathlab practice are lacking. We compared safety of intracoronary FD-OCT imaging to intravascular ultrasound (IVUS) imaging in a large real-world series of consecutive patients who underwent invasive imaging during coronary catheterization in our centre. METHODS AND RESULTS: This is a prospective, single-centre registry of patients scheduled for coronary angiography or intervention undergoing intracoronary imaging with FD-OCT or IVUS between April 2008 and December 2013. Intra-procedural and major in-hospital adverse events that could be possibly related to invasive imaging were registered routinely by the operator as part of our clinical report and prospectively recorded in our database. These events were retrospectively individually adjudicated by an independent safety committee. Between April 2008 and December 2013, 13 418 diagnostic or interventional coronary catheterization procedures were performed. Of these, 1142 procedures used OCT and 2476 procedures used IVUS. Invasive imaging-related complications were rare, did not differ between the two imaging methods (OCT: n = 7, 0.6%; IVUS: n = 12, 0.5%; P = 0.6), and were self-limiting after retrieval of the imaging catheter or easily treatable in the catheterization laboratory. No major adverse events, prolongation of hospital stay, or permanent patient harm was observed. CONCLUSION: FD-OCT is safe in an unselected and heterogeneous group of patients with varying clinical settings.

Comparison of acute expansion of bioresorbable vascular scaffolds versus metallic drug-eluting stents in different degrees of calcification: An Optical Coherence Tomography Study.

OBJECTIVES: The acute expansion of bioresorbable vascular scaffolds (BRS) and drug-eluting stents (DES) in lesions with different extent of calcification was compared by Optical Coherence Tomography (OCT). BACKGROUND: The acute mechanical performance of polymeric BRS in calcified lesions is poorly understood. METHODS: Acute device performance in lesions treated with either BRS(N = 50) or DES (N = 50) was compared using Optical Coherence Tomography (OCT). According to angiographic degree of calcification the lesions were divided in three groups: no/mild, moderate and heavy calcification. Device performance was assessed with the following parameters by OCT: mean scaffold area, eccentricity index (EI), symmetry index (SI) and percentage incomplete strut apposition (ISA). RESULTS: One hundred lesions from 85 patients (BRS/DES; 37/48) were analyzed. Scaffold area and SI were similar between BRS and DES groups in the three calcification subgroups. Compared to DES, EI in BRS was marginally lower in the no/mild calcification group (0.86 ± 0.03 versus 0.88 ± 0.03, p = 0.018) but was similar in the moderate and heavy calcification groups. Compared to DES, percentage ISA struts in BRS was similar in the no/mild calcification group and was significantly lower in the moderate and heavy calcification groups (2.96 ± 2.36 versus 6.78 ± 4.61%, p = 0.002 and 1.82 ± 2.40 versus 8.89 ± 8.25%, p = 0.025 respectively). CONCLUSIONS: With adequate lesion preparation, implantation of BRS in a population reflective of clinical practice, resulted in a similar luminal gain compared to DES as measured by OCT, regardless of the degree of angiographic calcification, while acute malapposition is lower with BRS in moderately and heavily calcified lesions. The clinical significance of our findings warrants further evaluation in future studies. © 2016 Wiley Periodicals, Inc.

Automated characterisation of lipid core plaques in vivo by quantitative optical coherence tomography tissue type imaging.

AIMS: Qualitative criteria for plaque tissue characterisation by OCT are well established, but quantitative methods lack systematic validation in vivo. High optical attenuation coefficient µt has been associated with unstable plaque features, such as lipid core. The purpose of this study was to validate optical coherence tomography (OCT) attenuation imaging for tissue characterisation in vivo, specifically to detect lipid core in coronary atherosclerotic plaques, and to evaluate quantitatively the ability of OCT attenuation imaging to differentiate thin-cap (TCFA) and thick-cap fibroatheroma (FA). METHODS AND RESULTS: We prospectively enrolled 85 patients undergoing imaging of a native coronary segment by both OCT and near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS). Ninety-eight NIRS-positive 4 mm plaque segments were selected and matched to the OCT data. Two experienced OCT readers classified the plaque type using OCT criteria. A cap thickness of 65 µm was used to differentiate TCFA and FA. We computed an index of plaque attenuation (IPA) in the 4 mm blocks, and assessed the association of this index with plaque type. IPA differentiated between TCFA and FA (AUC=0.82 in ROC analysis; p<0.0001). LCBI was numerically, but not significantly, higher in TCFA compared to FA (p=0.097). CONCLUSIONS: IPA is an unbiased reproducible measure of tissue optical properties. The fraction of pixels with attenuation coefficient ≥11 mm-1 can identify TCFA.

The OPTIS Integrated System: real-time, co-registration of angiography and optical coherence tomography.

The efficacy of an IVUS-guided stent implantation strategy to improve acute results and clinical outcome has been described previously. OCT is another technique which allows high-resolution intracoronary imaging. However, the use of invasive imaging modalities to guide PCI has, as yet, played a limited role in current clinical practice. This may be partly explained by the expertise required for interpretation and clinical decision making. We present a novel technology which enables real-time co-registration of OCT images with angiography. This will simplify matching cross-sectional images to their geographic position on the angiogram, thereby facilitating imaging-guided PCI.

Long-Term (>10 Years) Prognostic Value of Dobutamine Stress Echocardiography in a High-Risk Cohort.

The prognostic value of dobutamine stress echocardiography (DSE) at >10-year follow-up is unknown. The aim of this study was to assess the very long-term prognostic value of DSE in a high-risk cohort of patients with known or suspected coronary artery disease. This prospective, single-center study included 3,381 patients who underwent DSE from January 1990 to January 2003. Two-dimensional echocardiographic images were acquired at rest, during dobutamine stress, and during recovery. Follow-up events were collected and included overall mortality, cardiac death, nonfatal myocardial infarction, and revascularization. The incremental value of DSE in the prediction of selected end points was evaluated using multivariate Cox proportional hazard analysis. During a mean follow-up of 13 ± 3.2 years (range 7.3 to 20.5 years), there were 1,725 deaths (51%), of which 1,128 (33%) were attributed to cardiac causes. Patients with an abnormal DSE had a higher mortality rate (44% vs 35% at 15-year follow-up, p <0.001) than those with a normal DSE. When comparing echocardiographic variables at rest to variables at maximum dose dobutamine, the chi-square of the test improved from 842 to 870 (p <0.0001) and from 684 to 740 (p <0.0001) for all-cause mortality and cardiac death, respectively. DSE provided incremental value in predicting all-cause mortality, cardiac death, and hard cardiac events. There seems, however, to be a "warranty period" of approximately 7 years, when the survival curves of a normal and abnormal DSE no longer diverge.

Long-term prognostic value of exercise technetium-99m tetrofosmin myocardial perfusion single-photon emission computed tomography.

BACKGROUND: Exercise (99m)Tc-tetrofosmin single-photon emission computed tomography (SPECT) is a useful tool for short- and medium-term risk stratifications. Currently, the long-term prognostic application of this technique has not been evaluated. METHODS AND RESULTS: Exercise (99m)Tc-tetrofosmin was performed in 655 consecutive patients. Ten patients who underwent revascularization <60 days after nuclear testing were excluded from the analysis. The present data are based on 638 patients with complete follow-up. An abnormal SPECT study was defined as the presence of fixed and/or reversible perfusion defects. End points were cardiac death, nonfatal infarction, and late coronary revascularization. A total of 344 (54%) patients had an abnormal SPECT study. Perfusion defects included fixed defects alone in 186 patients (29%) and reversible defects in 158 (25%) patients. During a mean follow-up of 11.0 ± 3.3 years, 174 (27%) patients died (all-cause mortality). Nonfatal myocardial infarction occurred in 76 (12%) patients, and late coronary revascularization was performed in 194 (30%) patients. Univariable and multivariable Cox proportional hazard regression analyses showed that exercise (99m)Tc-tetrofosmin SPECT provided prognostic information incremental to clinical data and exercise test data. Patients with a normal SPECT had a relatively favorable long-term prognosis, in contrast to patients with an abnormal study who had a significantly increased risk of cardiac events. The SPECT parameters abnormal scan, reversible defect, and summed rest score were strong predictors of long-term outcome. CONCLUSION: Exercise (99m)Tc-tetrofosmin myocardial perfusion SPECT has an incremental long-term prognostic value over clinical and stress test parameters for the prediction of major adverse cardiac events.