Daniel Chamié

A next-generation bioresorbable coronary scaffold system: from bench to first clinical evaluation: 6- and 12-month clinical and multimodality imaging results.

OBJECTIVES This study sought to perform clinical and imaging assessments of the DESolve Bioresorbable Coronary Scaffold (BCS). BACKGROUND BCS, which is drug eluting, may have potential advantages compared with conventional metallic drug-eluting stents. The DESolve system, designed to provide vessel support and neointimal suppression, combines a poly-l-lactic acid-based scaffold with the antiproliferative myolimus. METHODS The DESolve First-in-Man (a non-randomized, consecutive enrollment evaluation of the DESolve myolimus eluting bioresorbable coronary stent in the treatment of patients with de novo native coronary artery lesions) trial was a prospective multicenter study enrolling 16 patients eligible for treatment. The principal safety endpoint was a composite of cardiac death, myocardial infarction, and clinically indicated target lesion revascularization. The principal imaging endpoint was in-scaffold late lumen loss (LLL) assessed by quantitative coronary angiography (QCA) at 6 months. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) imaging was performed at baseline and 6 months; multislice computed tomography (MSCT) was performed at 12 months. RESULTS Acute procedural success was achieved in 15 of 15 patients receiving a study scaffold. At 12 months, there was no scaffold thrombosis and no major adverse cardiac events directly attributable to the scaffold. At 6 months, in-scaffold LLL (by QCA) was 0.19 ± 0.19 mm; neointimal volume (by IVUS) was 7.19 ± 3.56%, with no evidence of scaffold recoil or late malapposition. Findings were confirmed with OCT and showed uniform, thin neointimal coverage (0.12 ± 0.04 mm). At 12 months, MSCT demonstrated excellent vessel patency. CONCLUSIONS This study demonstrated the feasibility and efficacy of the DESolve BCS. Results showing low in-scaffold LLL, low % neointimal volume at 6 months, no chronic recoil, and maintenance of lumen patency at 12 months prompt further study. (DESolve First-in-Man; EudraCT number 2011-000027-32).

Volumetric quantification of fibrous caps using intravascular optical coherence tomography

The rupture of thin-cap fibroatheroma accounts for most acute coronary events. Optical Coherence Tomography (OCT) allows quantification of fibrous cap (FC) thickness in vivo. Conventional manual analysis, by visually determining the thinnest part of the FC is subject to inter-observer variability and does not capture the 3-D morphology of the FC. We propose and validate a computer-aided method that allows volumetric analysis of FC. The radial FC boundary is semi-automatically segmented using a dynamic programming algorithm. The thickness at every point of the FC boundary, along with 3-D morphology of the FC, can be quantified. The method was validated against three experienced OCT image analysts in 14 lipid-rich lesions. The proposed method may advance our understanding of the mechanisms behind plaque rupture and improve disease management.

Frequency-domain optical coherence tomography assessment of unprotected left main coronary artery disease-a comparison with intravascular ultrasound.

To investigate safety and feasibility of imaging unprotected left main (ULM) using frequency‐domain optical coherence tomography (FD‐OCT) compared with intravascular ultrasound (IVUS).

Optical coherence tomography endpoints in stent clinical investigations: strut coverage

Late stent thrombosis (LST) and very LST (VLST) are infrequent complications after drug-eluting stent (DES) implantation, but they carry a significant risk for patients. Delayed healing, which may be represented by incomplete stent coverage, has been observed in necropsy vessel specimens treated with DES. As a result, in vivo assessment of stent coverage, as well as stent apposition using optical coherence tomography (OCT), have been recently used as surrogate safety endpoints in clinical trials testing DES platforms. By adopting strut coverage assessed by OCT, one can assess the safety profile of the new generation of DES in preregistration studies. This article focuses on stent strut coverage as a central predictor of late DES thrombosis from the histopathological point of view, discusses the limitations of the current imaging modalities and presents the technical characteristics of OCT for the detection of neointimal coverage after stent implantation. We also review the preclinical and clinical investigations using this novel imaging modality.

Automatic stent detection in intravascular OCT images using bagged decision trees

Intravascular optical coherence tomography (iOCT) is being used to assess viability of new coronary artery stent designs. We developed a highly automated method for detecting stent struts and measuring tissue coverage. We trained a bagged decision trees classifier to classify candidate struts using features extracted from the images. With 12 best features identified by forward selection, recall (precision) were 90%–94% (85%–90%). Including struts deemed insufficiently bright for manual analysis, precision improved to 94%. Strut detection statistics approached variability of manual analysis. Differences between manual and automatic area measurements were 0.12 ± 0.20 mm2 and 0.11 ± 0.20 mm2 for stent and tissue areas, respectively. With proposed algorithms, analyst time per stent should significantly reduce from the 6–16 hours now required.

A novel drug‐coated scoring balloon for the treatment of coronary in‐stent restenosis: Results from the multi‐center randomized controlled PATENT‐C first in human trial

Scoring balloons produce excellent acute results in the treatment of in‐stent restenosis (ISR), fibro‐calcific and bifurcation lesions but have not been shown to affect the restenosis rate. A novel paclitaxel‐coated scoring balloon (SB) was developed and tested to overcome this limitation.

Clinical, angiographic, and intravascular ultrasound results of the VestSaync II trial.

We sought to assess the long term efficacy of the novel VESTAsync™ Eluting Stent (VES) combining a Cro‐Co platform with a nanothin‐microporous hydroxyapatite surface coating impregnated with a polymer‐free low‐dose of Sirolimus (55 μg).

Serial Assessment of Vessel Interactions After Drug-Eluting Stent Implantation in Unprotected Distal Left Main Coronary Artery Disease Using Frequency-Domain Optical Coherence Tomography

OBJECTIVES This study sought to assess stent-vessel interactions after drug-eluting stent (DES) implantation in unprotected left main coronary artery (ULM) by frequency-domain optical coherence tomography (FD-OCT). BACKGROUND Percutaneous coronary intervention using DES in ULM has been increasingly performed in routine practice. Recently, FD-OCT assessments of DES-vessel interactions have been used as surrogates for DES safety; however, there are no FD-OCT studies in ULM. METHODS We prospectively enrolled 33 consecutive patients with ULM disease treated with sirolimus- (n = 11) and everolimus-eluting stents (n = 22). FD-OCT assessments were performed post-percutaneous coronary intervention and at 9-month follow-up. Three different segments of ULM were compared: distal (DIS), bifurcation (BIF), and ostial-body (BODY). The primary endpoints were percentages of uncovered and malapposed struts at 9-month follow-up, and the secondary endpoint was neointimal hyperplasia area. RESULTS We analyzed 25,873 stent struts. Significant differences were demonstrated for percentage of uncovered struts (3.4%, 11.7%, and 18.7%, respectively for DIS, BIF, and BODY; p < 0.05 for all the comparisons). Malapposition was also more common in BODY (5.3%) than in DIS (0.6%) and BIF (2.0%) segments (p < 0.05 for BODY vs. DIS, and BODY vs. BIF). Equivalent neointimal hyperplasia areas were demonstrated in all segments. Acute malapposition rates led to different patterns of DES-vessel interactions at 9-month follow-up. CONCLUSIONS Distinct patterns of DES-vessel interactions were demonstrated in different segments of ULM. Acute stent strut malapposition affects these findings.

Serial Angiography and Intravascular Ultrasound: Results of the SISC Registry (Stents In Small Coronaries)

OBJECTIVES The aim of this study was to evaluate the novel CardioMind Sparrow (CMS) stent (CardioMind, Inc., Sunnyvale, California) against the Multi-Link Pixel (MLP) stent (Guidant Corp., Santa Clara, California) for small vessel percutaneous coronary intervention (PCI). BACKGROUND The CMS consists of a guidewire-based, self-expandable, ultra-thin nitinol stent with smaller profile and improved flexibility and deliverability. The performance of this novel device against a standard balloon-expandable stent for small vessel PCI has not been determined. METHODS Twenty-one patients were treated with the CMS and compared with 30 patients treated with MLP. Only single de novo lesions <14 mm in length, in native vessels of 2.0 to 2.5 mm were included. The primary goal was the comparison of quantitative coronary angiography lumen loss and intravascular ultrasound intimal hyperplasia (IH) formation between groups at 6 months. RESULTS Clinical characteristics were similar between groups. The CMS cohort had smaller vessels (2.20 +/- 0.20 mm vs. 2.43 +/- 0.16 mm, p < 0.0001) and shorter lesions (10.86 +/- 3.19 mm vs. 13.12 +/- 2.79 mm, p = 0.0091). Six-month late loss was significantly lower among CMS cohort (0.73 +/- 0.57 mm vs. 1.11 +/- 0.72 mm, p = 0.038). By intravascular ultrasound, 6-month IH volume was similar between groups (1.45 +/- 0.46 mm(3)/mm vs. 1.65 +/- 1.02 mm(3)/mm, p = 0.50). However, CMS presented a mean 13.39% expansion of its volumes, resulting in a significantly lower percentage of IH volumetric obstruction (31.94 +/- 8.19% vs. 39.90 +/- 4.72%, p = 0.0005). CONCLUSIONS Despite producing similar amounts of IH volume, the self-expanding CMS stent presented chronic expansion of its volumes, better accommodating the neoformed tissue and resulting in significantly lower late loss and percent of IH volumetric obstruction in comparison with the MLP stent.

Optical Coherence Tomography and Fibrous Cap Characterization.

The pathophysiology of acute coronary syndromes has long been associated with atherosclerotic plaque rupture. Inflammation, thinning, and disruption of the fibrous cap have been implicated with the final processes leading to plaque rupture, but confirmation of these mechanisms of coronary thrombosis in humans has been hampered by the lack of imaging methods with sufficient resolution to resolve fibrous cap characterization and thickness in vivo. Intravascular optical coherence tomography (OCT) provides images with micron-level axial and lateral resolution, enabling detailed visualization of micro-structural changes of the arterial wall. The present article provides an overview of the potential role of OCT in identifying and characterizing fibrous cap morphology, thickness, and inflammation in human coronary plaques.