Yasir Bouchi

Vasomotor Function Comparative Assessment at 1 and 2 Years Following Implantation of the Absorb Everolimus-Eluting Bioresorbable Vascular Scaffold and the Xience V Everolimus-Eluting Metallic Stent in Porcine Coronary Arteries: Insights From In Vivo Angiography, Ex Vivo Assessment, and Gene Analysis at the Stented/Scaffolded Segments and the Proximal and Distal Edges

OBJECTIVES The purpose of this study was to assess and compare in vivo the restoration of vasomotor function following Absorb bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, California) and metallic Xience V (XV) (Abbott Vascular, Santa Clara, California) stent implantations in porcine coronary arteries at 1 and 2 years. BACKGROUND Drug-eluting metallic coronary stents induce sustained vasomotor dysfunction, and preliminary observations from arteries with bioresorbable scaffolds have indicated partially restored vasoreactivity. METHODS A total of 15 Absorb BVS (3.0 × 18.0 mm) and 14 XV (3.0 × 18.0 mm or 3.0 × 12.0 mm) stents were randomly implanted in the main coronaries of 12 nonatherosclerotic swine. The effect of implant on vasomotor performance (constrictive and expansive) was measured in the stented/scaffolded segments and the 5-mm proximal and distal adjacent segments in vivo by angiography assessing mean luminal diameter changes following infusion of vasoactive agents at 1 year (n = 6) and 2 years (n = 6) as well as ex vivo at 2 years using a tissue chamber apparatus. Endothelial cell function and smooth muscle cell phenotype gene marker levels were evaluated with quantitative real-time polymerase chain reaction. RESULTS The scaffolded Absorb BVS segments showed fully restored constrictive response compared with XV implanted vessels at 1 year: -24.30 ± 14.31% versus -1.79 ± 6.57% (p < 0.004) and at 2 years: -28.13 ± 14.60% versus -3.90 ± 6.44% (p < 0.004). The early restoration of vasomotor function within the scaffolded segments reached a peak at 1 year and did not significantly change up to 2 years. The vasoactive responses of Absorb BVS-implanted vessels within the scaffolded segments were similar to those observed within the proximal and distal edge segments at both time points. Conversely, the stented XV segments demonstrated significantly impaired constrictive response compared with the distal XV edges at 1 year: -1.79 ± 6.57% versus -21.89 ± 7.17% (p < 0.0002) and at 2 years: -3.90 ± 6.44% versus -21.93 ± 15.60% (p < 0.03). Ex vivo assessment of contraction induced by PGF2α and relaxation induced by substance P of isolated BVS segments compared with XV-treated segments generated greater contraction force of 3.94 ± 0.97 g versus 1.83 ± 1.03 g (p < 0.05), and endothelial-dependent relaxation reached 35.91 ± 24.74% versus 1.20 ± 3.79% (p < 0.01). Quantitative real-time polymerase chain reaction gene analysis at 2 years demonstrated increased Connexin 43 messenger ribonucleic acid levels of Absorb BVS-treated vessels compared with XV-treated vessels: 1.92 ± 0.23 versus 0.77 ± 12 (p < 0.05). CONCLUSIONS Absorb BVS-implanted coronary arteries demonstrate early functional restoration of the scaffolded and adjacent segments at 1 year, which is preserved up to 2 years.

Biocorrodible metals for coronary revascularization: Lessons from PROGRESS-AMS, BIOSOLVE-I, and BIOSOLVE-II

The impetus for developing drug-eluting bioresorbable scaffolds (BRS) has been driven by the need for elastic and transient platforms instead of stiff and permanent metallic implants in diseased coronary anatomies. This endeavor would prevent acute recoil or occlusion, allow sealing of post-procedural dissections following acute barotrauma, provide inhibition of in-segment restenosis through efficient drug-elution and would further prepare the vessel to enter a reparative phase following scaffold resorption. Biocorrodible metallic platforms have been introduced as alternatives to bioresorbable polymeric scaffolds for the treatment of significant atherosclerosis and in view of the body of evidence derived from recent clinical trials we elaborate on the clinical safety and efficacy of these devices in interventional cardiology.

Feasibility of Optical Coherence Tomography-Derived Computational Fluid Dynamics in Calcified Vessels to Assess Treatment With Orbital Atherectomy.

A 72-year-old male patient presented with stable angina, and coronary angiography showed a heavily calcified mid left anterior descending coronary artery lesion (diameter stenosis ≈ 75%). Optical coherence tomographic (OCT) assessment (C7-XRsystem, C7 Dragonfly catheter; LightLab Imaging, St. Jude

Coronary and Peripheral Vasomotor Responses to Mental Stress

Background Coronary microvascular dysfunction may contribute to myocardial ischemia during mental stress (MS). However, the role of coronary epicardial and microvascular function in regulating coronary blood flow (CBF) responses during MS remains understudied. We hypothesized that coronary vasomotion during MS is dependent on the coronary microvascular endothelial function and will be reflected in the peripheral microvascular circulation. Methods and Results In 38 patients aged 59±8 years undergoing coronary angiography, endothelium‐dependent and endothelium‐independent coronary epicardial and microvascular responses were measured using intracoronary acetylcholine and nitroprusside, respectively, and after MS induced by mental arithmetic testing. Peripheral microvascular tone during MS was measured using peripheral arterial tonometry (Itamar Inc, Caesarea, Israel) as the ratio of digital pulse wave amplitude compared to rest (peripheral arterial tonometry ratio). MS increased the rate‐pressure product by 22% (±23%) and constricted epicardial coronary arteries by −5.9% (−10.5%, −2.6%) (median [interquartile range]), P=0.001, without changing CBF. Acetylcholine increased CBF by 38.5% (8.1%, 91.3%), P=0.001, without epicardial coronary diameter change (0.1% [−10.9%, 8.2%], P=not significant). The MS‐induced CBF response correlated with endothelium‐dependent CBF changes with acetylcholine (r=0.38, P=0.03) but not with the response to nitroprusside. The peripheral arterial tonometry ratio also correlated with the demand‐adjusted change in CBF during MS (r=−0.60, P=0.004), indicating similarity between the microcirculatory responses to MS in the coronary and peripheral microcirculation. Conclusions The coronary microvascular response to MS is determined by endothelium‐dependent, but not endothelium‐independent, coronary microvascular function. Moreover, the coronary microvascular responses to MS are reflected in the peripheral microvascular circulation.

SHORTER TELOMERE LENGTH IS ASSOCIATED WITH LOWER LEVELS OF CIRCULATING PROGENITOR CELLS

Leucocyte telomere length (LTL) is a biological marker of aging which has been associated with decreased survival. Bone marrow-derived circulating progenitor cells (CPC) are involved in vascular repair and regeneration, and reduced CPC counts are associated with poor outcomes. We sought to determine