Investigating the performance of four specific types of material grafts and their effects on hemodynamic patterns as well as on von Mises stresses in a grafted three-layer aortic model using fluid-structure interaction analysis

One of the important parts of the cardiac system is aorta which is the fundamental channel and supply of oxygenated blood in the body. Diseases of the aorta represent critical cardiovascular bleakness and mortality around the world. This study aims at investigation of hemodynamic parameters in a two-dimensional axisymmetric model of three-layer grafted aorta using fluid–structure interaction (FSI). It assumes that a damaged part of aorta, which may happen as a result of some diseases like aneurysm, dissection and post-stenotic dilatation, is replaced with a biomaterial graft. Four types of grafts materials so-called Polyurethane, Silicone rubber, Polytetrafluoroethylene (PTFE) and Dacron are considered in the present study. The assumption of linear elastic and isotropic material is set for the both aorta's wall and aforementioned grafts. Blood is considered as an incompressible and Newtonian fluid. The results indicate higher displacement in Polyurethane and silicone rubber in comparison with other two. Furthermore, results reveal that blood flow velocity has slightly higher values in PTFE and Dacron grafted models compared to Polyurethane and Silicone rubber ones. Even though there are some differences in hemodynamic patterns in these grafted models, they are not considerable as much as von Mises stresses across the graft-aorta intersections are. This study shows that the types of material grafts play an important role in the amount of stresses particularly at intersections of aorta and graft.     

The importance of depression and alcohol use in coronary artery bypass graft surgery patients: risk factors for delirium and poorer quality of life

Objective To investigate whether depression, anxiety and stress increase the risk for delirium and poor quality of life (QOL) after coronary artery bypass (CABG) surgery. Methods A total of 180 CABG patients (mean age of 63.5 ± 10.1 years, 82.2% males) completed baseline and postoperative self-report questionnaires to assess distress and QOL. Incident delirium was diagnosed postoperatively with a structured clinical interview and patients were monitored every day post-operatively for confusion and disturbance in consciousness. Results Delirium developed in 63 persons (35% of sample). After adjustment for covariates, delirium was significantly associated with depression [odds ratio (OR): 1.08; 95% confidence interval (CI): 1.03–1.13, P = 0.003], anxiety (OR: 1.07; 95% CI: 1.02–1.13, P = 0.01) and stress (OR: 1.05; 95% CI: 1.00–1.09, P = 0.03). Preoperative depression scores were associated with poorer QOL including bodily pain (β = -0.39, P = 0.013), vitality (β=-0.32, P = 0.020), social functioning (β = -0.51, P ≤ 0.001), emotional role function (β = -0.44, P = 0.003) and general health (β = -0.33, P = 0.038). Among the covariates, harmful levels of alcohol use was consistently associated with poorer QOL. Conclusions Depression and harmful levels of alcohol use were consistently associated with poorer QOL whereas depression, anxiety and stress were associated with delirium risk. These findings point to further research examining depression and harmful levels of alcohol use in coronary heart disease populations undergoing coronary revascularization.     

Percutaneous coronary intervention of or through saphenous vein grafts or internal mammary arteries: the impact of stents, adjunctive pharmacology, and multicomponent distal protection.

We hypothesized that the use of stents and aggressive adjunctive pharmacotherapies has been associated with lower rates of complicating myocardial infarction (MI) and improved long-term outcomes compared to either previous balloon-only percutaneous coronary intervention (PCI) or atheroablative intervention for lesions of or through saphenous vein grafts (SVGs) and/or internal mammary arteries (IMAs). PCI of SVG has been complicated by relatively high rates of procedural MI and less favorable long-term outcomes than native vessel PCI, stimulating the development and application of an array of technologies. This study was based on retrospective review of stent-era (1999-2004) 5-year experience of a single center with 95 SVG procedures in 85 patients and 20 IMA procedures in 20 patients. These cases were compared with the previously published experience of one of the operators during the balloon-only period and literature review of the application of multiple technologies to SVG intervention, as well as consideration of the reoperation alternative. There was one in-hospital death each in the SVG cohort (1%) and in the IMA cohort (5%). There were SIX procedural MIs (6%), defined by total CK > normal, and 19 procedural MIs (20%) based on troponin-I > 1.0. Follow-up has been from 4 months to 5 years (average, 2.5 years), with 91% survival and one late CABG in the IMA group. SVG PCI with stents and adjunctive pharmacotherapies is associated with relatively low rates of procedural MI and favorable long-term outcomes.     

Resuscitative Endovascular Balloon Occlusion of the Aorta Using a Low-Profile Device is Easy and Safe for Emergency Physicians in Cases of Life-Threatening Hemorrhage

Background

Bleeding from hemorrhagic shock can be immediately controlled by blocking the proximal part of the hemorrhagic point using either resuscitative thoracotomy for aortic cross-clamping or insertion of a large-caliber (10–14Fr) resuscitative endovascular balloon occlusion of the aorta (REBOA) device via the femoral artery. However, such methods are very invasive and have various complications. With recent progress in endovascular treatment, a low-profile REBOA device (7Fr) has been developed.

The future of saphenous vein as a coronary artery bypass conduit

Continuing widespread use of autologous saphenous vein for coronary artery bypass grafting seems unavoidable despite its poor-term patency. We review here the evidence that platelet activation is responsible for early and late vein graft occlusion and conclude that other mechanisms probably contribute to late occlusions. We suggest that a rational strategy to improve vein graft patency should include: improved endothelial preservation during surgical implantation; use of better antiplatelet agents, in particular those which prevent platelet adhesion as well as aggregation; reduction of risk factors including serum cholesterol; and application of agents (e.g. heparin) which inhibit smooth muscle cell proliferation directly. We draw parallels between the pathogenesis of vein graft occlusion and coronary atherosclerosis and suggest that testing strategies for improving vein graft patency may also shed light on atherogenesis.     

Five cases of non-typhoidal Salmonella endovascular infection

The incidence of human non-typhoidal Salmonella (NTS) infection has increased in many countries. Endovascular infection is one of the most serious forms of extraintestinal infection. Five patients with NTS endovascular infection treated at Middlemore Hospital, Auckland, New Zealand, are presented here. All persons with NTS bacteraemia who are older than 50 years and have a risk of atherosclerosis should be evaluated for possible endovascular infection.     

Safety of cardiac catheterization via peripheral vascular grafts

There are few data concerning the complications and technical difficulties encountered when cardiac catheterization is performed using peripheral bypass grafts for vascular access. All cardiac catheterizations performed at our institution from January 1, 1984 to April 1, 1991 were retrospectively reviewed to assess the in-hospital clinical outcomes in patients who had arterial access for catheterization achieved via prosthetic graft puncture. Seventeen procedures had percutaneous puncture of a vascular graft from a total of 2,929 arterial catheterizations performed. The interval from graft placement to catheterization was 7.5 ± 1.1 years. Arterial sheaths were employed in all cases and corresponded to the catheter size, with 5F systems used in 53% and 7F or larger systems used in the remaining patients. No intraprocedural or postprocedural complications were recognized. Technical difficulties were limited to the inability to selectively cannulate a nondominant right coronary artery in 1 patient. We conclude that percutaneous introduction of an arterial sheath and left heart catheterization via remotely implanted vascular bypass grafts is not associated with an increased risk of procedural complications or technical difficulties. © 1993 Wiley-Liss, Inc.     

Left internal mammary graft stenosis and restenosis following angioplasty and stenting

Coronary bypass grafts using the internal mammary artery usually have an excellent record of success and long term patency. We report a 42 year old man who initially presented with a history of atypical left sided chest pain, who had coronary artery bypass surgery for a severe stenosis in his proximal left anterior descending coronary artery (LAD) and moderate stenosis of his proximal circumflex artery, with his LIMA being grafted to his mid-LAD and a saphenous venous graft to the proximal LAD. He subsequently developed multiple stenoses in the LIMA graft which required coronary augioplasty and stenting, on more than one occasion, in view of very rapid restenosis within the LIMA graft.


Keywords: graft patency; left internal mammary artery grafts; restenosis; stenosis     

Long-term outcome of endovascular therapy for acute basilar artery occlusion

The long-term functional outcome of acute basilar artery occlusion (BAO) patients who received modern endovascular therapy (EVT) is unclear. We sought to assess the long-term functional outcome of BAO patients treated with EVT and determine the prognostic factors associated with favorable outcome. We enrolled consecutive BAO patients who received EVT between December 2012 and December 2018 in this observational study. Baseline characteristics and outcomes were presented. Multivariable logistic regression analysis was performed to identify the prognostic factors associated with long-term outcome. Among the 177 BAO patients included in this study, 80 patients (45.2%) obtained favorable outcome and 97 patients (54.8%) had unfavorable outcome at long-term follow-up with a median observation time of 12 months (interquartile range, 3–19). A total of 67 patients (37.9%) died. National Institutes of Health Stroke Scale (NIHSS), posterior circulation Alberta Stroke Program Early Computed Tomography Score (pc-ASPECTS), time from stroke onset to recanalization, and recanalization condition were identified as independent predictors for long-term outcome. Over 40% of BAO patients who were treated with modern EVT achieved favorable outcome at long-term follow-up. NIHSS, pc-ASPECTS, time from stroke onset to recanalization, and recanalization condition were identified as independent prognostic factors of long-term outcome.