OBJECTIVE: The internal thoracic artery (ITA) is a useful conduit for coronary artery bypass grafting (CABG) and the patency rate is indispensable. Recently we have developed a method for increasing ITA blood flow during surgery by directly injecting phosphodiesterase III inhibitor (PDE III-I) into the left ITA (LITA) to prevent ...

PURPOSE OF REVIEW: Several options exist for detecting and preventing stenosis in polytetrafluoroethylene grafts and arteriovenous fistulae for haemodialysis. Although observational studies show a significant benefit of such strategies, data from randomized trials are limited. This review describes recently published information that has helped to advance this field during the ...

BACKGROUND: Complex use of arterial conduits has resurrected concerns about the adequacy of conduit flow. The T-graft is the extreme example of this trend. Our purpose was to identify the limitation of single source inflow and to compare flow capacity with completion coronary flow. METHODS: Between February 1999 and November ...

The major complication that occurs with grafts used as vascular access for hemodialysis, is stenosis at the venous anastomosis or in the draining vein. 75% area stenosis is considered significant as thrombotic occlusion may occur. The aim of this experimental study was to evaluate invasive and noninvasive indices to detect ...

Recombinant tissue factor pathway inhibitor (rTFPI) was immobilized on collagen impregnated (CI) knitted Dacron surfaces and its resistance to fibrin deposition evaluated following exposure to nonanticoagulated whole blood. Recombinant TFPI readily adsorbed to the CI Dacron surface and maintained its inhibitory activity. Under static conditions, rTFPI treated CI Dacron showed ...

AIM: Aside from the high incidence of venous stenosis, high-output failure and peripheral steal syndromes remain serious problems of vascular access. Meanwhile commercial tapered grafts are available to address this topic, but little is known about its effect neither on graft flow nor on hemodynamics. METHODS: Anastomotic models were constructed ...

BACKGROUND: The authors studied the impact of neutrophil activation, detected in experimental models, on reperfusion injury in clinical renal transplantation. METHODS: Forty-five patients from a larger trial comparing three immunosuppressive protocols were recruited: perioperative antithymocyte globulin (ATG) with low initial cyclosporine A (CsA) triple therapy (group A, n=15); two-dose basiliximab ...

BACKGROUND: Despite widespread use of radial artery as a bypass conduit in coronary artery bypass surgery, flow readjustment that takes place in the hands and fingers after the removal of the radial artery is poorly understood. METHODS: Using pulse volume recording plethysmography, a semiquantitative measurement of digital blood flow was ...

We have studied cerebral blood flow velocity (CBFV) and cerebral autoregulation (CA) in 23 orthotopic liver transplantation (OLT) patients using transcranial doppler. CBFV was continuously recorded using a fixed (helmet) 2-Mz probe through the trans-temporal window. CA changes were studied using a linear regression analysis of percentile changes in CBFV ...

OBJECTIVE: We are developing a hybrid arterial bypass graft of compliant poly(carbonate-urea)urethane (MyoLink), endothelial and smooth muscle cells (SMCs). To enhance adhesion of SMCs we assessed various attachment factors and the effect of pre-conditioning on cell retention. METHODS: MyoLink segments were coated with either RGD, superfibronectin, fibronectin, fibronectin-like engineered polymer ...

BACKGROUND: Blood flow (Qa) measurements are an important step in the surveillance protocol of haemodialysis vascular access (VA). The glucose pump test (GPT) is a new test for Qa measurement based on the dilution of a constant glucose infusion. The aim of this study is to verify the clinical accuracy ...

OBJECTIVES: Graft failure has been reported when the arterial conduit, such as the internal thoracic artery (ITA) or the right gastroepiploic artery (GEA), is grafted to a lower grade coronary artery stenosis. The shear stress as a significant factor affecting graft patency was compared between the arterial conduit and the ...

BACKGROUND: It is not well established whether early following surgery the blood flow of arterial composite Y-grafts may efficiently meet the flow demand of the coronary system. The aim of this study was to evaluate whether early after surgery arterial composite Y-grafts may increase the blood flow in response to ...

AIM: The aim of this paper was to examine effectiveness of maintaining venous blood flow through dissected, but not harvested, grafts on prostaglandin I2 production and endothelial cell regeneration after implantation. METHODS: Using 10 dogs, 8-cm-long bilateral jugular veins were dissected; 1 was harvested, and immersed in heparinized blood for ...

BACKGROUND: Intermittent pneumatic compression (IPC) may increase blood flow through infrainguinal arterial grafts, and has potential clinical application as blood flow velocity attenuation often precedes graft failure. The present study examined the immediate effects of IPC applied to the foot (IPC(foot)), the calf (IPC(calf)) and to both simultaneously (IPC(foot+calf)) on ...

BACKGROUND: Bivalirudin is a short-acting direct thrombin inhibitor, with advantages over unfractionated heparin for anticoagulation in cardiac surgery. We hypothesized that bivalirudin is not associated with a clinically important increase in blood loss compared with heparin with protamine reversal in patients undergoing off pump coronary artery bypass (OPCAB) surgery. We ...

Outflow distribution at the distal anastomosis of infrainguinal bypass grafts remains unquantified in vivo, but is likely to influence flow patterns and haemodynamics, thereby impacting upon graft patency. This study measured the ratio of distal to proximal outflow in 30 patients undergoing infrainguinal bypass for lower limb ischaemia, using a ...

Angiogenesis and reperfusion of blood vessels were analysed qualitatively, at the light- and electron-microscopical levels, in solid pineal autografts placed intracerebrally in adult rats (post-transplantation survival times: 1, 3, 7, 10, 14 and 28 days). Reperfusion of blood vessels was studied in sections from immersion-fixed brains incubated to demonstrate the ...

From October 2000 through April 2001, we prospectively evaluated the flow characteristics of the left internal thoracic artery (LITA) graft in a homogenous group of 44 men with isolated severe proximal left anterior descending coronary artery stenosis who underwent elective coronary artery bypass grafting with cardiopulmonary bypass. We performed transthoracic ...

A hitherto unpublished means of testing the patency across an end-to-side venous anastomosis is described. It relies on the elasticity of the venous walls to produce ballooning when the appropriate segments of the veins are occluded and blood is flowing unimpeded across the end-to-side anastomosis. It is foolproof, easy to ...

Transit-time Doppler can be used for intraoperative assessment of graft patency, by measuring conduit flow, or from the calculation of a derivation of the spectral waveform. The optimal timing of measurement is when graft flows are maximal. Fifteen patients underwent multivessel coronary bypass surgery without the use of cardiopulmonary bypass. ...

BACKGROUND: We investigated the changes occurring in cerebral cortical oxygenation during off-pump coronary artery bypass (OPCAB) surgery using near infrared spectroscopy (NIRS). METHODS: Measurement of cerebral cortical oxygenation changes included concentration of deoxygenated hemoglobin [HHb], oxygenated hemoglobin [O(2)Hb], changes in the redox status of the cytochrome c oxidase [Cyt-Ox], cerebral ...

Peripheral blood is used almost exclusively as the source of hematopoietic cells for autografting, but the best source of cells for allografting is the subject of considerable discussion and debate. Randomized studies comparing unstimulated bone marrow with G-CSF-mobilized peripheral blood in the sibling allogeneic setting have indicated a trend to ...

BACKGROUND: Total arterial grafting is increasingly preferred in coronary artery bypass grafting, but it increases blood loss. Aprotinin (Trasylol; Bayer Corp, Leverkusen, Germany) reduces blood loss in cardiac surgery but has not been subjected to a randomized trial in total arterial grafting. METHODS: A single-center, randomized, double blind, placebo-controlled trial ...

BACKGROUND: Internal thoracic arterial grafts (ITA) in coronary artery bypass surgery provide excellent long-term patency results. Due to the elevated incidence of sternal infections following pedicled ITA harvesting, blood supply to the sternum has gained the focus of attention. This study sought to evaluate real time parameters of sternal microcirculation ...

OBJECTIVE: To assess endoscopically the hemodynamic function of arterioarterial (AA) anastomoses in twin-twin transfusion syndrome (TTTS) and monochorionic selective intrauterine growth restriction (IUGR). MATERIALS AND METHODS: The videotapes of TTTS and IUGR patients undergoing laser surgery between July 1997 and December 2001 were reviewed for the presence of AA anastomoses. ...

Arterial occlusive disease remains the leading cause of death in western countries and often requires vascular reconstructive surgery. The limited supply of suitable small-diameter vascular grafts has led to the development of tissue engineered blood vessel substitutes. Many different approaches have been examined, including natural scaffolds containing one or more ...

OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have ...

The aim of this study was to compare flow characteristics of LIMA-LAD anastomoses constructed using two different techniques. Thirty patients underwent MIDCAB using either simple continuous suture (20) or separate nitinol U-clips (10). Intraoperative transit time flow measurements were recorded. Preoperative variables were similar in the two groups. Anastomosis time ...

PURPOSE: To provide functional reference values in single and sequential vein grafts by using magnetic resonance (MR) flow mapping and to examine the effect of percutaneous intervention (PCI) on coronary artery bypass graft function. MATERIALS AND METHODS: Fast MR flow mapping at baseline and during adenosine-induced stress was performed in ...

Extracorporeal arteriovenous carbon dioxide removal (AVCO2R) using percutaneous cannulae and a low resistance gas exchanger achieves near total CO2 removal, allowing lung rest and potentially improving survival. AVCO2R, redesigned to allow ambulation, has potential as treatment for severe chronic obstructive pulmonary disease or rehabilitation before lung transplant. The purposes of ...

In Takayasu arteritis recurrent brain ischemia, due to bypass graft failure, is frequent. Redo bypass grafting from the ascending aorta may be at risk if a failing but patent graft that is critical for brain blood flow is present, because partial clamping the ascending aorta may disturb graft flow if ...

OBJECTIVE: It is not well established whether the blood flow of arterial composite Y-grafts can efficiently respond to the flow demand of the coronary system early postoperatively. The aim of this study was to evaluate if soon after the operation, arterial composite Y-grafts can increase blood flow in response to ...

Vascular access placement is a key management issue for hemodialysis patients. Despite being well regarded as the access of first choice, the native arteriovenous fistula (AVF) remains underutilized in the United States. The first part of this review examines recent epidemiology studies addressing patient factors associated with the use of ...

The purpose of this study was to investigate the hemodynamic implications of a proximal shift in the aortic bifurcation that results from abdominal aortic aneurysm (AAA) stent graft deployment. A flow model was constructed in which an anatomically accurate model of the aorta was subjected to physiologic pulsatile flow. The ...

Spatial and temporal dynamics of silica (SiO2) were examined in a morphologically complex reservoir, based on data collected between high-flow year and low-flow year. SiO2 averaged 3.4 mg/L and varied from 0.1 to 9.7 mg/L depending on the year and the location. The paired sample test of SiO2 showed that ...

OBJECTIVE: to determine the degree of interobserver variation of color-flow duplex scanning of infrainguinal arterial bypass grafts. METHODS: two experienced vascular technologists randomly assessed bypass grafts in 32 consecutive patients, using a color-flow duplex scan. In pre-defined segments the highest peak systolic velocity (PSV(max)) and end-diastolic velocity (EDV) were measured ...

We present experimental and computational results that describe the level, distribution, and importance of velocity fluctuations within the venous anastomosis of an arteriovenous graft. The motivation of this work is to understand better the importance of biomechanical forces in the development of intimal hyperplasia within these grafts. Steady-flow in vitro ...

BACKGROUND AND OBJECTIVE: The study investigated the impact of induced arterial hypotension for the facilitation of endovascular stent-graft placement in patients with thoracic aortic aneurysm on cerebral blood flow velocity and neurological/neurocognitive outcome. METHODS: In 27 ASA III patients, cerebral blood flow velocity was recorded during induced arterial hypotension for ...

PURPOSE: Pseudoaneurysm is a known complication of arteriovenous grafts in chronic hemodialysis and can result in graft disruption or thrombosis if left untreated. This study evaluated the safety and efficacy of endovascular repair with Wallgraft endoprosthesis (Boston Scientific, Inc, Watertown, Mass) in a porcine arteriovenous graft (AVG) pseudoaneurysm model. Materials ...

The purpose of this prospective study was to evaluate graft patency of off-pump coronary artery surgery intraoperatively by transit-time flow measurement and to compare this technique with postoperative magnetic resonance flow mapping. Twenty patients (13 men and 7 women; mean age, 679 +/- 76 yr) underwent off-pump coronary artery surgery. ...

OBJECTIVE: Y-composite grafting with the radial artery (RA) is often used in off-pump coronary artery bypass grafting (OPCAB). However, the early flow reserve of the left internal thoracic artery (LITA) as a blood source of the Y-composite RA graft has not been delineated. METHODS: The size of the LITA was ...

OBJECTIVE: Internal thoracic artery (ITA) flow competition is a diversion of graft flow through intact ITA branches with a net decrease in perfusion to the grafted coronary. Although a widely acknowledged phenomenon, the conditions under which flow competition occurs have not been established. This is examined in a canine H-graft ...

BACKGROUND: Vascular access dysfunction is a major source of hemodialysis patient morbidity. The NKF K/DOQI Guidelines promote access flow monitoring as the most preferred access surveillance method and have established access flow thresholds for fistulography: an absolute threshold of 600 ml/min and a dynamic threshold of flow less than 1000 ...

BACKGROUND: Harvesting the radial artery (RA) with ultrasonic dissection with the Harmonic Scalpel reduces spasm induced by surgical handling. Topical exposure to phentolamine methanesulphonate (Regitine) exerts an additional effect of vasodilatation. METHODS: Between January and December 2002, the RA was harvested as a pediculated vessel with the Harmonic Scalpel in ...

OBJECTIVE: We have previously shown that baboon grafts subjected to elevated shear stress exhibit an increase in luminal area through atrophy of the neointimal layer. This study was designed to investigate the smooth muscle cell (SMC) growth kinetics during early regression and evaluate the influence of nitric oxide (NO) in ...

BACKGROUND: Many investigators have measured outflow resistance (R) following peripheral bypass procedures, but correlations with graft patency have been weak. This is because the primary determinants of graft patency are the size and quality of the conduit, not its outflow bed. Efforts at separating conduit resistance from outflow resistance have ...

Angiogenesis (the formation of new blood vessels) is essential for the growth of new tissue, tissue repair and wound healing. Tissue engineering, the construction of new tissue and organs for reparative purposes, relies on angiogenesis for the vascularisation of these new grafts. In tissue engineering, the emphasis to date has ...

Blood flow to canine saphenous nerve grafts either in contact with a healthy soft-tissue bed or isolated from the soft-tissue bed by entubulation was quantitated at 3, 7, 14, and 28 days after surgery with radionuclide-labeled microspheres and evaluated histomorphometrically. At 3 days there was no statistical difference between the ...

OBJECTIVE: Total extracardiac cavopulmonary connection is an established procedure, but the best spatial arrangement remains controversial. On the basis of our clinical experience with total extracardiac cavopulmonary connection, we performed quantitative and qualitative flow analysis on total extracardiac cavopulmonary connection models simulating the two most frequent arrangements applied to our ...