Transthyretin-related amyloid in a saphenous vein. Histological diagnosis in a patient undergoing coronary artery bypass surgery

Amyloidosis is an underdiagnosed and challenging disease with clinical and etiologic heterogenicity, requiring amyloid subtyping because of the distinctive prognostic and therapeutic impact. Transthyretin amyloidosis is more common in elderly patients, and in such population undergoing cardiovascular surgery, it could be worthy to be investigated. We herein describe an unusual case of transthyretin-related vascular amyloidosis in an 81-year-old man undergoing coronary artery bypass surgery. Diagnosis done after histology showed an intimal eccentric thickening in a remnant segment of the right saphenous vein that was harvested for grafting. Transthyretin-related amyloidosis was demonstrated by histochemical Congo Red staining under polarized light and by immunohistochemistry, corresponding to the intimal thickening. The thorough histological analysis was crucial for the diagnosis of a previously unknown transthyretin-related vascular amyloidosis.

Conduits Used in Coronary Artery Bypass Grafting: A Review of Morphological Studies

There is a significant variety of vascular conduits options for coronary bypass surgery. Adequate graft selection is the most important factor for the success of the intervention. To ensure durability, permeability, and bypass function, there must be a morphological similarity between the graft and the coronary artery. The objective of this review was to analyze the morphological characteristics of the grafts that are most commonly used in coronary bypass surgery and the coronary arteries that are most frequently occluded. We included clinical information regarding the characteristics that determine the behavior of the grafts and its permeability over time. Currently, the internal thoracic artery is the standard choice for bypass surgery because of the morphological characteristics of the wall that makes less prone to developing atherosclerosis and hyperplasia. The radial and right gastroepiploic arteries are the following second and third best options, respectively. The ulnar artery is the preferred choice when other conduits are not feasible.

Optical Coherence Tomography of De Novo Lesions and In-Stent Restenosis in Coronary Saphenous Vein Grafts (OCTOPUS Study)

BACKGROUND

The OCTOPUS registry prospectively evaluates the procedural and long-term outcomes of saphenous vein graft (SVG) PCI. The current study assessed the morphology of de novo lesions and in-stent restenosis (ISR) in patients undergoing PCI of SVG.

METHODS AND RESULTS

Optical coherence tomography (OCT) of SVG lesions in consecutive patients presenting with stable CAD and ACS was carried out. Thirty-nine patients (32 de novo and 10 ISR lesions) were included in the registry. ISR occurred in 5 BMS and 5 DES. There were no differences in the presence of plaque rupture and thrombus between de novo lesions and ISR. Lipid-rich tissue was identified in both de novo lesions and in ISR (75% vs. 50%, P=0.071) with a higher prevalence in BMS than in DES (23% vs. 7.5%; P=0.048). Calcific de novo lesions were detected in older grafts as compared with non-calcific atheromas (159±57 vs. 90±62 months after CABG, P=0.001). Heterogeneous neointima was found only in ISR (70% vs. 0, P<0.001) and was observed with similar frequency in both BMS and DES (24% vs. 30%, P=0.657). ISR was detected earlier in DES than BMS (median, 50 months; IQR, 18-96 months vs. 27 months; IQR, 13-29 months, P<0.001).

CONCLUSIONS

OCT-based characteristics of de novo and ISR lesions in SVG were similar except for heterogeneous tissue, which was observed only in ISR. (Circ J 2016; 80: 1804-1811).

Association between platelet to lymphocyte ratio and saphenous vein graft disease in patients with stable angina pectoris

OBJECTIVE

In this study, we aimed to investigate the relation of platelet to lymphocyte ratio (PLR) in saphenous vein graft disease (SVGD) in patients with stable angina pectoris after coronary artery bypass graft surgery.

METHODS

A total of 455 patients were included in the study. There were 210 patients with SVGD and 245 patients without SVGD. The effects of different variables on SVGD were computed in logistic regression analysis.

RESULTS

The platelet count, lymphocyte count, PLR, high-density lipoprotein (HDL), Na, and ALT were significantly associated with SVGD. In multivariate regression analysis, HDL and PLR were found to be significantly associated with SVGD.

CONCLUSION

To the best of our knowledge, this is the first study showing the significant association of PLR with SVGD. This study suggests that PLR can be used as a marker of SVGD because it is an easily available and inexpensive test.

γ-Secretase inhibitor DAPT attenuates intimal hyperplasia of vein grafts by inhibition of Notch1 signaling

The proliferation and high plasticity of vascular smooth muscle cells (vSMCs) are the major reasons for restenosis of vein grafts. N-[N-(3, 5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester (DAPT), specific inhibitor of γ-secretase, has been shown to regulate vSMC proliferation and differentiation through the Notch signaling pathway, but the pathophysiological importance of these findings in venous grafts has not yet been determined. A rat vein graft model was employed wherein the left jugular vein was surgically interposed into the left common carotid artery. Daily subcutaneous injections of DAPT or placebo (DMSO) were administered postoperatively (control animals received no treatment). We showed that DAPT can inhibit restenosis of vein grafts by inhibiting vSMC proliferation and increasing apoptosis in vivo. Notch1 signaling was highly active during the development of intima thickening. By blocking the Notch signaling pathway, the γ-secretase inhibitor DAPT can significantly attenuated intima thickening. These changes in vein grafts coincided with enhanced binding of myocardin to the smooth muscle-specific protein SM22 and smooth muscle myosin heavy chain at the promoters of vSMC differentiation-specific genes. These studies showed that DAPT can restore the vSMC phenotype and inhibit vSMC proliferation through suppression of the Notch1 signaling pathway, and thus opens a new avenue for the treatment of restenosis in vein grafts.