Interplay of supramolecular organization, metallophilic interactions, phase changes, and luminescence in four polymorphs of IrI(CO)2(OC(CH3)CHC(CH3)N(p-tol)).

Four polymorphs of IrI(CO)2(OC(CH3)CHC(CH3)N(p-tol)) have been characterized by single crystal X-ray crystallography. While all contain the same molecular unit with no significant structural variations within the molecules, all show different degrees of metallophilic interactions between the planar molecules. Three of these (the amber, the pale yellow, and the orange forms) are stable at room temperature, while the fourth, the L.

A reversible polymorphic phase change which affects the luminescence and aurophilic interactions in the gold (I) cluster complex, [mu3-S(AuCNC7H13)3](SbF6).

Crystallographic examination of [mu3-S(AuCNC7H13)3](SbF6) shows that it undergoes a reversible phase change from orthorhombic to monoclinic upon cooling. At 190 K, the structure shows that two cations self-associate to form a pseudo-octahedral array of six gold atoms connected by both intra- and interionic aurophilic interactions. On cooling, the clusters become less symmetric, and in one, the interionic Au.

Electron and hydrogen-atom self-exchange reactions of iron and cobalt coordination complexes.

Reported here are self-exchange reactions between iron 2,2'-bi(tetrahydro)pyrimidine (H(2)bip) complexes and between cobalt 2,2'-biimidazoline (H(2)bim) complexes. The (1)H NMR resonances of [Fe(II)(H(2)bip)(3)](2+) are broadened upon addition of [Fe(III)(H(2)bip)(3)](3+), indicating that electron self-exchange occurs with k(Fe,e)(-) = (1.1 +/- 0.

Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound.

The objective of this study was to determine the quantitative intravascular ultrasound (IVUS) and angiographic changes that occur during 1 year follow-up after renal artery stent placement, given that restenosis continues to be a limitation of renal artery stent placement. 38 consecutive patients with symptomatic renal artery stenosis treated with Palmaz stent placement were studied prospectively. IVUS and angiography were performed at the time of stent placement and at 1 year follow-up.

A comparison of balloon injury models of endovascular lesions in rat arteries.

Background: Balloon injury (BI) of the rat carotid artery (CCA) is widely used to study intimal hyperplasia (IH) and decrease in lumen diameter (LD), but CCA's small diameter impedes the evaluation of endovascular therapies. Therefore, we validated BI in the aorta (AA) and iliac artery (CIA) to compare it with CCA.

Methods: Rats underwent BI or a sham procedure (control).

Predictors for clinical success at one year following renal artery stent placement.

Purpose: To determine pretreatment variables that may predict 1-year clinical outcome of stent placement for renal artery stenosis.

Methods: In a prospective study, 40 consecutive patients (29 men; mean age 60 +/- 9.1 years) with angiographically proven atherosclerotic renal artery stenosis were treated with stent placement because of drug resistant hypertension (n=14), renal function impairment (n=14), or both (n=12).

Midterm follow-up of balloon-expandable ePTFE endografts in the femoropopliteal segment.

Purpose: To evaluate the midterm clinical outcome of patients treated with a balloon-expandable polytetrafluoroethylene (ePTFE) endograft for long-segment occlusive disease of the femoropopliteal segment.

Methods: Eighty-nine patients (68 men; median age 69 years, range 43-81) with disabling claudication (n=73) or critical ischemia (n=16) were treated with an ePTFE endograft (mean length 29 cm) for 7 stenosis (mean length 9 cm) and 82 occlusions (mean length 19 cm) in the femoropopliteal segment. The follow-up protocol included Doppler ankle-brachial pressure measurement and duplex scanning or angiography of the endograft at 6-month intervals.

Gamma radiation induces positive vascular remodeling after balloon angioplasty: a prospective, randomized intravascular ultrasound scan study.

Background: Endovascular brachytherapy (EBT) has been shown to prevent restenosis after percutaneous transluminal coronary angioplasty (PTA) in both animal and clinical studies. However, as yet, the effect of EBT on peripheral arteries is unknown.

Objective: This intravascular ultrasound scan (IVUS) study evaluates the effect of EBT on the extent of plaque growth and vascular remodeling after PTA of the femoropopliteal artery.

Validation of transrectal ultrasonographic volumetry for orthotopic prostate tumours in mice.

Orthotopic human prostate tumour models in athymic nude mice are regarded as being most suitable for fundamental and pre-clinical research on prostate cancer. The anatomic localization of the tumour in the pelvis, however, provides little possibility for monitoring tumour growth or regression. To assess time-related changes in orthotopic tumour volume, we applied transrectal ultrasonography (TRUS) to the murine prostate.

Rationale and design for the SARIS trial; effect of statin on atherosclerosis and vascular remodeling assessed with intravascular sonography. Effect of Statin on Atherosclerosis and vascular Remodeling assessed with Intravascular Sonography.

Purpose: The SARIS study (effect of Statin on Atherosclerosis and vascular Remodeling assessed with Intravascular Sonography) is a prospective randomized multicenter trial designed to assess both morphological and functional cardiovascular effects of atorvastatin.

Methods: Participating centers will include 50 patients with normal to mildly elevated cholesterol levels eligible for balloon angioplasty and/or stent placement of the common iliac artery. Patients will be randomized to 1-year treatment with either low-dose (10 mg) or high-dose (80 mg) atorvastatin.

Intravascular ultrasound evidence for stabilization of compensatory enlargement of the femoropopliteal segment after endograft placement.

Purpose: To document whether the vasodilatory response seen at the anastomotic segment 6 months after placement of a balloon-expandable endograft in the femoropopliteal segment progresses between 6 and 24 months.

Methods: Twelve patients (9 men; median age 65 years, range 47-75) treated with an investigational polytetrafluoroethylene (PTFE) endograft for obstructive disease of the femoropopliteal segment were studied with intravascular ultrasound (IVUS) immediately after placement and at 6 months (first follow-up period) and 24 months (second follow-up period). Matched IVUS cross sections derived from the endograft and the anastomotic segment were analyzed for changes in lumen (LA), vessel (VA), and plaque areas (PLA).

Early experience with intravascular ultrasound in evaluating the effect of statins on femoropopliteal arterial disease: hypothesis-generating observations in humans.

The purpose of this study was to compare the vascular response seen with intravascular ultrasound (IVUS) at 1-year follow-up between statin-treated and non-statin-treated patients. Patients (n = 10) undergoing percutaneous transluminal angioplasty (PTA) of the femoropopliteal artery were studied with IVUS immediately after PTA and at 1-year follow-up. In nondilated matched vascular segments, the change in lumen, vessel, and plaque volume was assessed.

Reproducibility of calcified lesion quantification: a longitudinal intravascular ultrasound study.

In view of a prospective intravascular ultrasound (IVUS) study, the reproducibility of the extent of the calcified lesion in IVUS images derived from separate pull-back maneuvers was assessed. Patients (n = 34) were imaged with IVUS before and after percutaneous transluminal angioplasty (PTA) and at 1-y follow-up. In the presence of a calcified lesion, the largest arc and the length of the matched calcified lesions was assessed.

Three-dimensional intravascular ultrasound assessment of abdominal aortic aneurysm necks.

Purpose: To document the accuracy of an automated analysis system for measuring lumen diameter and neck lengths of abdominal aortic aneurysms (AAAs) from intravascular ultrasound (IVUS) images and to describe additional features associated with 3-dimensional (3D) IVUS imaging.

Methods: Twenty-two aortic aneurysms were studied with IVUS. Lumen diameters obtained using the automated analysis system were compared with manual measurements from axial IVUS scans, as were neck lengths obtained using automated analysis versus those measured with the aid of a displacement sensing device.

Effect of simvastatin on restenosis after percutaneous transluminal angioplasty of femoropopliteal arterial obstruction.

This retrospective observational intravascular ultrasound study evaluated whether simvastatin therapy limits lumen area reduction 1-year after percutaneous transluminal angioplasty (PTA) by reducing reactive plaque growth, reducing reactive vasoconstriction, or both. This study showed that plaque growth is a general response 1 year after PTA regardless of the use of simvastatin; simvastatin has the potential to induce positive vascular remodeling, thereby reducing the occurrence of restenosis.

Progression of atherosclerosis at one-year follow-up seen with volumetric intravascular ultrasound in femoropopliteal arteries.

Volume measurements derived from intravascular ultrasound (IVUS) images assessed with an automated contour analysis system are accurate and reproducible. However, it is unknown to what extent plaque volume may change at follow-up. Therefore, the purpose of this longitudinal study is to examine whether IVUS is a sensitive means to identify progression of atherosclerosis and its derived primary end point plaque volume at 1-year follow-up.

Response of renal and femoropopliteal arteries to Palmaz stent implantation assessed with intravascular ultrasound.

Purpose: To establish the processes responsible for late lumen loss in renal and femoropopliteal Palmaz stents using intravascular ultrasound (IVUS).

Methods: The first 7 consecutive patients treated with stents for renal (n = 4) and femoropopliteal (n = 3) arterial occlusive disease were studied with IVUS immediately after angiographically successful stent placement (< 10% residual stenosis) and periodically during follow-up. Images of both stent edges and the most stenotic site inside the stent at followup were matched to the same cross sections captured immediately after stent placement for quantitative analysis.

Stent placement for renal arterial stenosis: where do we stand? A meta-analysis.

Purpose: To perform a meta-analysis of renal arterial stent placement in comparison with renal percutaneous transluminal angioplasty (PTA) in patients with renal arterial stenosis.

Materials And Methods: Studies dealing with renal arterial stent placement (14 articles; 678 patients) and renal PTA (10 articles; 644 patients) published up to August 1998 were selected. A random-effects model was used to pool the data.

Vascular response in the femoropopliteal segment after implantation of an ePTFE balloon-expandable endovascular graft: an intravascular ultrasound study.

Purpose: To use intravascular ultrasound (IVUS) to document changes in vascular dimensions after placement of a balloon-expandable endograft.

Methods: Thirteen patients (9 men; mean age 62 years, range 47-75) treated with an investigational polytetrafluoroethylene endograft for obstructive disease of the femoropopliteal segment were studied with IVUS immediately after endograft implantation and at follow-up. Corresponding IVUS cross sections were analyzed for changes in lumen, vessel, and plaque areas seen inside the endograft, in the anastomotic segment, and in the remote arterial segment.

Reproducibility of volumetric quantification in intravascular ultrasound images.

The reproducibility of volume measurements in intravascular ultrasound (IVUS) images derived from separate pull-back manoeuvres remains to be elucidated. Patients (n = 23) were imaged with IVUS prior to (first series) and following percutaneous transluminal angioplasty (PTA) (second series). In 15 patients, one matched vascular segment (3-4 cm in length), not subjected to PTA, was used for analysis of lumen, vessel and plaque volume using an automated contour analysis system.

Intravascular ultrasound evidence for coarctation causing symptomatic renal artery stenosis.

Background: A recent study of human cadaveric renal arteries revealed that renal artery narrowing could be due not only to atherosclerotic plaque compensated for by adaptive remodeling, but also to hitherto undescribed focal narrowing of an otherwise normal renal arterial wall (ie, coarctation). The present study investigated whether vessel coarctation could be identified in patients with symptomatic renal artery stenosis (RAS).

Methods And Results: Consecutive symptomatic patients with angiographically proven atherosclerotic RAS who were referred for stent placement were studied by 30-MHz intravascular ultrasound before intervention (n=18) or after predilatation (n=18).

Endovascular stent-grafts for aneurysms of the femoral and popliteal arteries.

Our objective was to investigate the preliminary use of endovascular stent-grafts for the treatment of femoropopliteal artery aneurysm. Ten patients with an aneurysm of the femoropopliteal artery referred for endovascular treatment were investigated. The series consisted of patients with a true aneurysm of the superficial femoral artery (n = 2); a true aneurysm of the popliteal artery (n = 4); an aneurysmal dilatation of a Biograft bypass (n = 2); a false aneurysm of the superficial femoral aneurysm (n = 1); and a false aneurysm of a composite bypass (n = 1).

Conductance method for the measurement of cross-sectional areas of the aorta.

A modified conductance method to determine the cross-sectional areas (CSAs) of arteries in piglets was evaluated in vivo. The method utilized a conductance catheter having four electrodes. Between the outer electrodes an alternating current was applied and between the inner electrodes the induced voltage difference was measured and converted into a conductance.