Diagnosis and management of type 2 endoleaks after endovascular aneurysm repair.

Endovascular repair is a major treatment advance in patients with large infrarenal abdominal aortic aneurysms. Since the FDA approved two commercial devices 2.5 years ago, over 40,000 patients have undergone this procedure in the United States.

Durability of benefits of endovascular versus conventional abdominal aortic aneurysm repair.

Purpose: Endovascular abdominal aortic aneurysm (AAA) repair is reported to result in less initial patient morbidity and a shorter hospital length of stay (LOS) when compared with conventional AAA repair. We sought to examine the durability of this result during the intermediate follow-up interval.

Methods: The records of all admissions for all patients who underwent AAA repair during a 26-month interval were reviewed.

Treatment of type 2 endoleaks after endovascular repair of abdominal aortic aneurysms: comparison of transarterial and translumbar techniques.

Objective: The exact significance of collateral endoleaks is unknown and a topic of great debate. Because of this uncertainty, some physicians choose to watch and wait while others aggressively treat these leaks. The purpose of this investigation was the evaluation of the efficacy of the two techniques used in the treatment of collateral endoleaks that occur after endovascular aneurysm repair.

Crystal structure of a phosphorylated Smad2. Recognition of phosphoserine by the MH2 domain and insights on Smad function in TGF-beta signaling.

Ligand-induced phosphorylation of the receptor-regulated Smads (R-Smads) is essential in the receptor Ser/Thr kinase-mediated TGF-beta signaling. The crystal structure of a phosphorylated Smad2, at 1.8 A resolution, reveals the formation of a homotrimer mediated by the C-terminal phosphoserine (pSer) residues.

Impact of exclusion criteria on patient selection for endovascular abdominal aortic aneurysm repair.

Purpose: Wide-ranging predictions have been made about the usefulness of endovascular repair for patients with abdominal aortic aneurysms (AAAs). The availability of US Food and Drug Administration-approved devices has removed the restrictions on patient selection, which had been controlled by device trials. This study examined the applicability of endovascular AAA repair and identified the anatomic barriers to successful endovascular AAA repair that should guide future device development.

Endovascular AAA repair in patients with renal insufficiency: strategies for reducing adverse renal events.

Vascular imaging, usually employing nephrotoxic contrast agents is relied upon for all aspects of endovascular AAA repair causing some to consider renal insufficiency a relative contraindication. We sought to determine if endovascular AAA evaluation and repair could be successfully accomplished by minimally or non-nephrotoxic modalities. Records and results for 98 consecutive patients undergoing endovascular AAA repair were reviewed.

Quantitative analysis of DNA binding by the Escherichia coli arginine repressor.

Allosteric activation of the hexameric arginine repressor (ArgR) for specific operator DNA binding appears to involve alteration in its quaternary structure. Current models for activation include subunit assembly and/or domain rearrangements in response to binding of the coeffector l-arginine. To investigate the molecular basis for ArgR operator interactions, we have carried out a series of quantitative analyses of ArgR subunit assembly and of the affinity, stoichiometry, cooperativity, and l-arginine- and DNA sequence-dependence of ArgR-DNA binding.

Endovascular repair of aortic aneurysms: critical events and adjunctive procedures.

Objective: We sought to define the learning curve relative to the incidence and range of intraoperative problems and to establish guidelines for troubleshooting during the endovascular repair of infrarenal aortic aneurysms.

Methods: We prospectively evaluated our first 75 consecutive cases over a 12-month period and focused on perioperative critical events and adjunctive procedures as categorical outcome measures collected during the operation. Patients were separated into three groups on the basis of the date of their operation, such that group 1 consisted of our first 25 cases, group 2 our next 25 cases, and group 3 our last 25 cases.

Effects of charged amino acids at b and c heptad positions on specificity and stability of four-chain coiled coils.

An understanding of the balance of chemical forces responsible for protein stability and specificity of structure is essential for the success of efforts in protein design. Specifically, electrostatic interactions between charged amino acids have been explored extensively to understand the contribution of this force to protein stability. Much research on the importance of electrostatic interactions as specificity and stability determinants in two-stranded coiled coils has been done, but there remains significant controversy about the magnitude of the attractive forces using such systems.

Balloon embolization of the internal iliac artery before aneurysm endograft deployment.

Six patients, ranging from 69 to 81 years of age, underwent iliac artery embolization with use of Detachable Silicon Balloons (DSB) 11-14 days before stent-graft repair of aneurysms. Balloons of 8.8-mm, 9.

A comparative study of peptide models of the alpha-domain of alpha-lactalbumin, lysozyme, and alpha-lactalbumin/lysozyme chimeras allows the elucidation of critical factors that contribute to the ability to form stable partially folded states.

alpha-Lactalbumin (alpha LA) forms a well-populated equilibrium molten globule state, while the homologous protein hen lysozyme does not. alpha LA is a two-domain protein and the alpha-domain is more structured in the molten globule state than is the beta-domain. Peptide models derived from the alpha-subdomain that contain the A, B, D, and 3(10) helices of alpha LA are capable of forming a molten globule state in the absence of the remainder of the protein.

Formation of a stable heterodimer between Smad2 and Smad4.

Smad proteins mediate transforming growth factor beta signaling from the cell membrane to the nucleus. Upon phosphorylation by the activated receptor kinases, the receptor-regulated Smad, such as Smad2, forms a heterocomplex with the co-mediator Smad, Smad4. This heterocomplex is then translocated into the nucleus, where it associates with other transcription factors and regulates expression of ligand-responsive genes.

The role of magnetic resonance angiography for endoprosthetic design.

Objectives: Many patients with aortic aneurysms have renal insufficiency and may be at increased risk when conventional imaging modalities (contrast-enhanced computed tomography and arteriography) are used for aortic endograft design. Our objective was to determine if magnetic resonance angiography (MRA) could be used as the sole imaging modality for endoprosthetic design.

Methods: A total of 96 consecutive patients who underwent endovascular repair of thoracic (5) and abdominal (91) aortic aneurysms (April 1998-December 1999) were included in this study.

Update on the Talent aortic stent-graft: a preliminary report from United States phase I and II trials.

Purpose: Phase I and phase II trials were conducted to determine the safety and efficacy of the Talent aortic stent-graft (Medtronic World Medical, Sunrise, Fla) in the treatment of infrarenal abdominal aortic aneurysms (AAA). This is a preliminary report of the technical results and 30-day clinical outcome of these trials.

Methods: Multicenter prospective trials were conducted to test the Talent stent-graft in high-risk and low-risk patient populations with AAA, including phase I feasibility and phase II clinical trials.

Gender-related differences in infrarenal aortic aneurysm morphologic features: issues relevant to Ancure and Talent endografts.

Purpose: The purpose of this study was to determine whether gender-related anatomic variables may reduce applicability of aortic endografting in women.

Methods: Data on all patients evaluated at our institution for endovascular repair of their abdominal aortic aneurysm were collected prospectively. Ancure (Endovascular Technologies (EVT)/Guidant Corporation, Menlo Park, Calif) and Talent (World Medical/Medtronic Corporation, Sunrise, Fla) endografts were used.

Failure of endovascular abdominal aortic aneurysm graft limbs.

Objective: Endovascular abdominal aortic aneurysm (AAA) grafts are subject to subsequent failure of endograft limbs. We sought to determine what device-related factors could be identified that might contribute to limb failure.

Methods: We reviewed the records of patients who had undergone endovascular AAA repair and femorofemoral bypass grafting at a single institution.

Aneurysm sac pressure measurements after endovascular repair of abdominal aortic aneurysms.

Objectives: The goal of endovascular grafting of abdominal aortic aneurysms (AAAs) is to exclude the aneurysm sac from systemic pressure and thereby decrease the risk of rupture. Unlike conventional open surgery, branch vessels in the sac (eg, lumbar artery and inferior mesenteric artery [IMA]) are not ligated and can potentially transmit pressure. The purpose of our investigation was to evaluate the feasibility of various interventional techniques for measuring pressure within the aneurysm sac in patients who had undergone endovascular repair of AAAs.

Dramatic recovery of renal function after 6 months of dialysis dependence following surgical correction of total renal artery occlusion in a solitary functioning kidney.

Revascularization of renal artery stenosis for the treatment of hypertension is an established procedure. In selected clinical scenarios, successful revascularization procedures may preserve or restore renal function. We present a 31-year-old man who underwent successful renal revascularization of a solitary functioning kidney after being dialysis dependent for approximately 190 days.

Brachial artery catheterization to facilitate endovascular grafting of abdominal aortic aneurysm: safety and rationale.

Purpose: Endovascular treatment of abdominal aortic aneurysms (AAAs) is a technically demanding procedure that is based on the complexity and multiplicity of steps and the guidewire and catheter manipulations required. Brachial artery catheterization is an adjunctive technique that can facilitate the placement of an endoluminal prosthesis.

Methods: Brachial access was used during endoluminal AAA repair in 79 of 103 consecutive patients with a modular-design stent-graft prosthesis at two institutions.

Limb kinking in supported and unsupported abdominal aortic stent-grafts.

Purpose: The occurrence of kinking of stent-graft limbs depends on the patient's anatomy and the device used. The purpose of this investigation was to determine the rates of limb kinking in supported and unsupported aortic stent-grafts.

Materials And Methods: The authors performed a retrospective review of patients undergoing placement of either a Guidant Ancure/EGS or Medtronic Talent aortic stent-graft for the treatment of abdominal aortic aneurysm as part of separate phase II and phase III clinical trials.

Relationship between preoperative patency of the inferior mesenteric artery and subsequent occurrence of type II endoleak in patients undergoing endovascular repair of abdominal aortic aneurysms.

Objectives: The purpose of this study was (1) to find out whether preoperative inferior mesenteric artery (IMA) patency (on radiographic imaging) predicts IMA-related endoleaks after endovascular repair of infrarenal abdominal aortic aneurysms, (2) to determine feasibility of measuring aneurysm sac pressures in patients with endoleaks, and (3) to report early evidence of effective endovascular obliteration of IMA endoleaks.

Methods: We studied 76 consecutive cases of infrarenal aortic aneurysms that were repaired with an endovascular approach (March 1998-April 1999).

Results: There were 13 (17%) endoleaks persistent 30 days after the procedure.

Safety of coil embolization of the internal iliac artery in endovascular grafting of abdominal aortic aneurysms.

Purpose: During endovascular grafting of an abdominal aortic aneurysm (AAA), iliac limb extension to the external iliac artery may be indicated when the common iliac artery is ectatic or aneurysmal. Preliminary or concomitant coil embolization of the internal iliac artery (IIA) is thus necessary to prevent potential reflux and endoleak. We sought to determine the safety of hypogastric flow interruption in this setting.

Endovascular grafting in patients with short proximal necks: an analysis of short-term results.

Objectives: To evaluate the safety of endovascular graft placement in patients with short proximal aneurysm necks, and assess factors contributing to endoleak formation.

Methods: 55 patients were enrolled over a two year period from five centers following the placement of a Talent endograft with a suprarenal stent. Preoperative and 30-day post-implant CT scans were retrospectively analyzed in a blinded fashion by two physicians.