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Biomedical subjects

E L Chaikof

Publications and source records attributed to E L Chaikof.

At least 19 recordsLinked to original sources
PubMed2001

Endovascular revascularization of renal artery stenosis in the solitary functioning kidney.

The treatment of renal artery stenosis by angioplasty and stenting is an effective and accepted alternative to surgery for the treatment of renovascular hypertension and preservation of renal function. We report the technical and clinical outcomes of renal artery stenting in patients with a solitary functioning kidney and renal artery stenosis. From October 1993 to November 1999, 30 stents were placed in the renal arteries of 27 patients (mean age 72+/-8 years) with a solitary functioning kidney and azotemia. The mean diameter renal artery stenosis was 86+/-14%. The mean preprocedure serum creatinine (Cr) level was 3.0+/-1.5 mg/dL (range 1.5-7.5 mg/dL), arterial blood pressure was 171+/-29/85+/-13 mmHg, and the number of antihypertensive drugs was 2.9+/-1.1. Indications for stenting were suboptimal balloon dilation (n = 16), intimal dissection (n = 6), and restenosis following angioplasty (n = 5). Atherosclerotic ostial lesions were present in 25 (93%) of 27 renal arteries. This represents the largest series of renal artery stenting in patients with a solitary functioning kidney, and demonstrates this treatment modality to be a relatively safe alternative to conventional surgery in this high-risk patient group. Most (74%) of the patients in this series had improved or stabilized renal function. Further efforts to define preprocedural indicators of success are necessary to identify the patients who may benefit from revascularization of their solitary kidney.

Aged↗
PubMed2001

Endovascular revascularization of renal artery stenosis: technical and clinical results.

PURPOSE: The natural history of renal artery stenosis is progression with subsequent deterioration of kidney function and development of renovascular hypertension. Percutaneous transluminal renal angioplasty is effective in the treatment of nonostial lesions but less effective for ostial stenoses. Because of the poor technical success experienced with percutaneous transluminal renal angioplasty, stenting of ostial stenoses is becoming the standard of endovascular care. In this retrospective study we analyzed the technical and clinical outcomes after renal artery stenting in 73 consecutive patients. PATIENTS AND METHODS: From July 1992 to January 1999, 88 Palmaz stents were deployed in 85 renal artery stenoses in 73 patients, with a mean age of 67.9 +/- 9.4 years. Twelve patients (16%) underwent bilateral stent placement. Atheromatous lesions were the most prevalent (99%: 82% ostial, 16% nonostial). Most stents were implanted for suboptimal balloon dilation (52%) or dissection (24%). Mean percent stenosis was 86% +/- 12%. Renal insufficiency (creatinine level > or = 1.5 mg/dL) was present in 50 (68%) patients, and uncontrolled hypertension (systolic > or = 160 mm Hg or diastolic > or = 90 mm Hg with more than two medications) was present in 57 (78%). RESULTS: Primary technical success was achieved in 89%. At the initial procedure, three additional stents were placed for residual stenoses, and urokinase was used to treat one intraprocedural stent thrombosis, resulting in an assisted primary technical success rate of 94%. Major complications occurred in 9.1% of stents placed: access artery thrombosis (n = 4), renal artery extravasation (n = 1), renal artery thrombosis (n = 1), and hematoma requiring operation (n = 2). Long-term clinical data were available on 69 (95%) patients at 20 +/- 17 months. Overall, a significant decrease in systolic and diastolic pressures (P <.001) and reduction of medication (P <.01) were noted without a change in renal function (P = NS). Angiography was performed on 22 patients at 11.3 +/- 10.3 months for persistent or worsening renal function or hypertension or for other reasons; 10 patients had significant restenoses in 14 renal arteries. CONCLUSION: Our retrospective analysis demonstrates that endovascular stenting of renal artery stenosis in patients with poorly controlled hypertension or deteriorating renal function is a safe and effective alternative treatment to surgical management.

Adult↗
PubMed2001

Age versus comorbidities as risk factors for complications after elective abdominal aortic reconstructive surgery.

PURPOSE: This study estimated the association between age and in-hospital postoperative complications, controlling for known or suspected risk factors, in a series of patients undergoing elective abdominal aortic reconstructive surgery (AAR). METHODS: This retrospective cohort study of outcome data with multivariate logistic regression analysis was conducted at Emory University Hospital, a tertiary care, university-affiliated hospital. All patients undergoing elective AAR between Jan 1, 1986, and Aug 1, 1996, were included (n = 856). An estimate of the odds ratio (OR) and 95% CI for the association between patient age and in-hospital major morbidity or mortality after elective AAR was made, controlling for significant risk factors. RESULTS: Among the 856 patients, 170 had a nonfatal complication (136 with major and 34 with minor complications), and 11 patients (1.3%) died. The final logistic regression model demonstrated a mild association between increasing age and rate of major postoperative complications, including death (for each increase in age of 10 years: OR, 1.23; 95% CI, 1.00-1.52; P =.052). Other significant covariates in the final model included cardiac disease (OR, 2.84; 95% CI, 1.18-6.86; P =.020), pulmonary disease (OR, 1.96; 95% CI, 1.35-2.84; P =.0004), and renal disease (OR, 2.57; 95% CI, 1.66-3.99; P =.0001). Increasing age was associated with a moderate increase in the rate of death (for each increase in age of 10 years: OR, 2.74; 95% CI, 1.22-6.16; P =.015) in a model with cardiac disease as the only significant covariate (OR, 14.67; 95% CI, 3.46-62.16; P =.0003). CONCLUSION: For patients undergoing elective AAR, increasing patient age is associated with a small increase in risk for in-hospital morbidity or mortality. However, significant cardiac, pulmonary, or renal disease is associated with a much greater risk of postoperative complications, and, therefore, advanced age should not be the sole basis of exclusion for otherwise suitable candidates for elective AAR.

Age Factors↗
PubMed2001

Mid-term results after endovascular repair of the abdominal aortic aneurysm.

PURPOSE: As a minimally invasive strategy for the treatment of patients with abdominal aortic aneurysm (AAA), endovascular repair has been embraced with enthusiasm because of the promise of achieving a durable result with a reduced risk of perioperative morbidity and mortality. Our mid-term experience with endovascular AAA repair was assessed by examining early and late clinical outcome in concurrent cohorts of patients stratified either as low-risk or as at increased-risk for intervention. METHODS: From April 1994 to December 1999, endovascular AAA repair was performed in 104 patients with commercially available systems. A subset of patients considered at increased risk for intervention (n = 51) were categorized as such based on a pre-existing history of ischemic coronary artery disease (73%), with documentation of myocardial infarction (57%) or congestive heart failure (29%), or because of the presence of chronic obstructive pulmonary disease, liver disease, or malignancy. RESULTS: The perioperative mortality rate (30-day) was 7.8% for patients at increased risk compared with 1.9% among those classified as low-risk (P = NS). There was no difference between groups in age (72 +/- 7 years vs 74 +/- 7 years; mean +/- SD), surgical time (221 +/- 90 minutes vs 192 +/- 68 minutes), blood loss (437 +/- 402 mL vs 331 +/- 238 mL), postoperative hospital stay (4.4 +/- 2.7 days vs 4.2 +/- 2.5 days), or days in the intensive care unit (1.2 +/- 1.6 days vs 0.6 +/- 1.3 days). Patients at increased risk of intervention had larger aneurysms than patients at low risk (58 +/- 11 mm vs 52 +/- 12 mm; P < .05). Stent grafts were successfully implanted in 47 (92%) patients at increased risk versus 50 (94%) patients at low risk (P = NS). Conversion rates to open operative repair were similar in increased-risk and low-risk groups at 3.9% and 5.7%, respectively. The initial endoleak rate was 21% versus 18% based on the first computed tomography performed (either at discharge or 1 month; P = NS). To date, patients at increased risk have been monitored for 14.6 +/- 12.4 months, and patients at low risk have been monitored for 17.7 +/- 15.0 months. Kaplan-Meier analysis for cumulative patient survival demonstrated a reduced probability of survival among those patients initially classified as at increased risk for intervention (P < .05, Mantel-Cox test). Both cohorts had similar 2-year clinical success rates of approximately 75%. CONCLUSION: Despite the use of an endovascular approach for aneurysm treatment, the risk of perioperative death and morbidity remains present for all patients including those who have no significant medical comorbidity. Moreover, although clinical success rates are comparable in both patient groups, 2 years after endovascular repair was performed, at least one in four patients was classified as a clinical failure. Given the continued uncertainty associated with clinical outcome and the need for close life-long surveillance, caution is dictated in advocating endovascular treatment for the patient who is otherwise considered an ideal candidate for standard open surgical repair.

Aftercare↗
PubMed2001

Soluble heparin-binding peptides regulate chemokinesis and cell adhesive forces.

The ability of a soluble heparin-binding peptide sequence derived from fibronectin to modulate the adhesion and chemokinetic migration behavior of arterial smooth muscle cells was assessed using a novel glass microsphere centrifugation assay and automated time-lapse fluorescence videomicroscopy, respectively. Treatment of cells grown on fibronectin-coated substrates with the soluble heparin-binding peptide resulted in the disassembly of focal adhesions, as assessed by immunohistochemical staining. These observations were consistent with an observed dose-dependent two- to fivefold reduction in cell-substrate adhesive strength (P < 0.001) and a biphasic effect on migration speed (P < 0.05). Moreover, heparin-binding peptides induced a twofold reduction (P < 0.01) in two-dimensional cell dispersion in the presence of a non-heparin-binding growth factor, platelet-derived growth factor-AB (PDGF-AB). Heparin-binding peptides were unable to mediate these effects when cells were grown on substrates lacking a heparin-binding domain. These data support the notion that competitive interactions between cell surface heparan sulfates with heparin-binding peptides may modulate chemokinetic cell migration behavior and other adhesion-related processes.

Animals↗
PubMed2000

Embryology, anatomy, and surgical exposure of the great abdominal vessels.

This article describes the embryology of the abdominal aorta and the anatomic features of its major visceral branches, including the celiac, superior mesenteric, and inferior mesenteric arteries. The common anatomic variants of these visceral vessels also are reviewed. Various operative techniques to gain surgical exposure to these vessels are described.

Aorta, Abdominal↗
PubMed2000

Subclavian artery disruption resulting from endovascular intervention: treatment options.

Endovascular intervention is a commonly accepted form of treatment in patients with subclavian artery stenosis. Complications will undoubtedly occur as the utility of catheter-based intervention continues to rise. We report two cases of subclavian artery disruption as a result of endovascular intervention. One patient had contrast extravasation after the deployment of a balloon-expandable stent in a stenotic subclavian artery, and the arterial injury was successfully treated with balloon tamponade. A second patient had a large subclavian pseudoaneurysm 4 months after a balloon-expandable stent placement. Successful repair was achieved in this patient by means of arterial reconstruction with a prosthetic bypass graft. These cases illustrate different therapeutic methods of treating subclavian artery rupture due to endovascular intervention.

Aged↗
PubMed2000

A porcine model of carotid artery thrombosis for thrombolytic therapy and angioplasty: application of PTFE graft-induced stenosis.

PURPOSE: To develop a porcine carotid artery thrombosis model for the evaluation of thrombolytic therapy and adjunctive angioplasty procedures. METHODS: Bilateral carotid thrombosis was induced in 16 pigs using endothelial crush injury followed by external polytetrafluoroethylene (PTFE, 5 x 2 cm2) wrap placement to create segmental carotid stenosis. Light microscopy was used to examine thrombus composition. Selective carotid catheterization was performed via a femoral approach. Two hours following carotid artery occlusion, a urokinase (250,000 IU) and heparin (1000 U) solution was pulse-sprayed in 1 carotid artery while the contralateral vessel received the control saline vehicle. The efficacy of thrombolytic therapy was assessed using carotid arteriography and intravascular ultrasound. The feasibility and technical efficacy of balloon angioplasty within the carotid stenosis model were also evaluated. RESULTS: Carotid artery occlusion occurred in 30 +/- 6 minutes following endothelial injury plus PTFE wrap placement. Histological examination of carotid arteries showed endothelial irregularity with fibrin-rich and platelet-rich thrombus. Urokinase was effective in recanalizing all occluded arteries (100%), while the control saline vehicle showed no effective thrombolysis (p < 0.001). Angioplasty was successful in restoring normal diameter in all arteries (100%). CONCLUSIONS: This carotid artery thrombosis model, which incorporates intimal injury with segmental stenosis, is simple to create and reproducible. It provides not only a model for the evaluation of thrombolytic therapy but also a practical training tool for adjunctive endovascular interventions.

Angiography↗
PubMed2000

An endovascular model of carotid stenosis for the evaluation of thrombolysis and angioplasty.

PURPOSE: To develop a porcine carotid artery thrombosis model using a novel stent-graft device to evaluate the efficacy of thrombolytic therapy and angioplasty procedures. METHODS: An endovascular device made from a tapered polytetrafluoroethylene graft inverted in a self-expanding nitinol stent was delivered to bilateral carotid arteries via a right femoral approach in 16 pigs. Carotid thrombotic occlusion ensued from flow stasis created by the intrastent stenosis. Via selective carotid catheterization from a femoral approach, urokinase (250,000 IU) was pulse-sprayed in one carotid artery while a control saline solution was infused in the contralateral vessel; delivery times were 1 hour, 8 hours, 3 days, or 6 days after carotid occlusion (4 animals per time period). After thrombolysis, balloon angioplasty was performed to maintain carotid patency. Arteriography and intravascular ultrasound were used to evaluate the efficacy of thrombolysis. Light microscopy was used for histological analysis of the thrombus. RESULTS: Carotid artery occlusion occurred in 15+/-8 minutes after stent-graft placement in all animals. Urokinase was effective in recanalizing all occluded arteries in the 1-hour, 4-hour, and 3-day groups (100%) but was effective in only 2 of 4 animals in the 6-day group (p < 0.05). Overall thrombolytic efficacy was 78%+/-7%. Control saline solution showed no thrombolytic effect (p < 0.001). Angioplasty successfully restored normal luminal diameter in all fully lysed arteries (100%). Histological analysis showed fibrin-predominant thrombus with a varying degree of platelet deposition. CONCLUSIONS: This endovascular approach, which creates a carotid stenosis using this novel stent-graft device, is reliable in producing carotid thrombosis. In our model, thrombolytic therapy was effective in restoring luminal patency, and the intraluminal stenosis is amenable to balloon angioplasty. The model is useful for the evaluation of antithrombotic therapy and adjunctive endovascular interventions.

Angioplasty, Balloon↗
PubMed1999

Endovascular treatment of vascular injuries.

The endovascular management of hemodynamically stable patients with traumatic vascular lesions is an appealing concept. In principle, many of the injuries detected at the time of diagnostic angiography can be treated at the same setting. Moreover, lesions that occur at the base of the skull or at infraclavicular and pelvic locations pose far less difficulty when managed by transcatheter techniques than by traditional surgical exposure. Even among more accessible injuries, standard surgical dissection is often complicated by the presence of hematoma or pseudoaneurysm, which causes obliteration of natural tissue planes, or arteriovenous fistulas that may complicate dissection because of associated regional venous hypertension. Thus, endovascular approaches may provide easier access to the target lesion, limit the morbidity often associated with surgical exploration, and reduce transfusion requirements. Nonetheless, the long-term consequence of placing an intravascular foreign body in a young patient is undefined, and the potential risk for a device infection cannot be ignored. Definitive answers to these issues await the outcome of longitudinal follow-up studies. Until that time, a prudent approach in the use of this new technology is appropriate.

Animals↗
PubMed1999

Cytomimetic biomaterials. 3. Preparation and transport studies of an alginate/amphiphilic copolymer/polymerized phospholipid film.

The significance of molecular design methodologies based upon membrane-mimetic systems lies in the ability to engineer robust materials of varying geometry with a high degree of reproducibility and molecular control over surface order and chemistry. However, non-covalently associated assemblies, in and of themselves, are often insufficiently robust for many applications. We have previously reported the in situ polymerization of a single phospholipid monolayer on a self-assembled film of octadecyltrichrolosilane (OTS) on glass, as well as the polymerization of phospholipids on an amphiphilic, dialkyl-containing terpolymer bound to a gold-coated silicon wafer. We now report the polymerization of a phospholipid monolayer assembly onto an alkylated hydrogel substrate with significant alteration in both surface chemistry and mass transport properties at the hydrogel-water interface. A general platform is thereby created for enhancing the control of either the local delivery of specific macromolecules or the immunoisolation barrier for many cell based therapies.

Alginates↗
PubMed1999

Anatomic changes after endovascular grafting for aneurysmal disease.

Long-term follow-up of controlled clinical trials of endovascular grafting for aortic aneurysms will provide data on the safety and efficacy of this new treatment to reduce morbidity and mortality compared with standard treatment. It will be several years before this information will be available, and careful analysis of surrogate markers for clinical success has value for predicting long-term outcome. One essential surrogate marker is aortic aneurysm diameter, which has traditionally been the most important variable in calculating rupture risk, and multiple studies have shown that aneurysms shrink after complete endovascular exclusion. Furthermore, measurements of aortic neck size and aortic length has shown interesting patterns that may affect the durability of endovascular repair and, thus, may suggest potential strategies for the design of future devices.

Aorta↗
PubMed1998

Concomitant aortic and renal artery reconstruction in patients on an intensive antihypertensive medical regimen: long-term outcome.

A beneficial effect in blood pressure control is presumed for patients on an intensive preoperative antihypertensive regimen who undergo empiric renal revascularization. Nonetheless, a noticeable decline in surgical cure rates for hypertension has been recently observed in patients with generalized atherosclerosis. The outcome of patients on multiple preoperative antihypertensive agents who underwent combined aortic and renal artery reconstruction was reviewed. The study population comprised 43 patients who underwent concomitant renal artery and aortic reconstruction for atherosclerotic disease between 1983 and 1995 and who were taking two or more antihypertensive medications and had a serum creatinine of less than or equal to 1.7 mg/dL. Operative management included an aortic reconstruction with either unilateral (n = 22) or bilateral (n = 19) aortorenal bypass or renal endarterectomy (n = 2). Operative mortality was 4.7% (2 of 43). The estimated 5-yr probability of survival was 83% (95% C.I. 0.70, 0.99). Late follow-up data on blood pressure control were available for review in 32 patients at a median follow-up of 37 months. Hypertension was cured in 1 (3%) and improved in an additional 15 (47%) patients. The numbers of antihypertensive medications taken preoperatively (mean = 2.7) declined at late follow-up (mean = 1.6). Notably, the largest reduction was observed with beta blockers (p = 0.006), central sympatholytics (p = 0.041), and angiotensin converting enzyme (ACE) inhibitors (p = 0.052). The number of preoperative antihypertensive medications was not significantly related to survival or to blood pressure improvement. However, uncontrolled preoperative hypertension despite antihypertensive therapy was associated with a favorable blood pressure response to operation (p < 0.001). Patients on an intensive antihypertensive regimen can safely undergo concomitant renal artery and aortic reconstruction for the empiric management of hypertension. Poorly controlled preoperative hypertension in the presence of multiple antihypertensive agents is a favorable marker for improved postoperative blood pressure control.

Aged↗
PubMed1998

The synthesis of neoglycophospholipid conjugates via reductive amination of omega-oxoalkylglycosides and phosphatidylethanolamines.

Phospholipid conjugates of mono- and disaccharides tethered with an n-decanyl spacer were efficiently synthesized via an improved reductive amination of deprotected omega-oxodecanyl beta-glycosides and phosphatidylethanolamines with or without alkenyl groups. The omega-oxodecanyl beta-glycosides were prepared by stereoselective glycosidation of glycosyl halides with 1, 10-decanediol followed by pyridinium dichromate oxidation. The acetyl groups of the omega-oxodecanyl beta-glycosides were removed with sodium methoxide prior to their conjugation with phosphatidylethanolamines.

Carbohydrate Sequence↗
PubMed1998

Continued expansion of aortic necks after endovascular repair of abdominal aortic aneurysms. EVT Investigators. EndoVascular Technologies, Inc.

BACKGROUND: Longitudinal studies have revealed that the aortic segment proximal to an infrarenal abdominal aortic aneurysm (AAA) is at risk for continued enlargement after a standard aneurysm repair. Similarly, preliminary reports have shown expansion of one or both aortic necks after endovascular repair. Although some investigators have suggested that this may be a transient effect, continued dilatation at the endograft attachment site could effect the overall device stability. METHODS: As part of a multi-institutional trial of endovascular grafting for the treatment of AAA, 59 patients were successfully implanted with straight endografts between February 1993 and January 1995. A morphometric analysis of aortic neck size was undertaken with serial review of computed tomography scans available through April 1997. The neck sizes at both graft attachment sites were measured, with investigators blinded to patient identity and date of scan. Changes in minor diameter were defined, annual interval expansion rates were calculated, and the data were correlated with endoleak, device migration, aneurysm size change, endograft diameter, attachment system fractures, and initial preimplant neck size. RESULTS: Significant aortic neck enlargement, particularly at the level of the distal neck, was observed for at least 24 months after AAA repair. The annual interval dilation rates of the proximal aortic neck were 0.7 +/- 2.1 mm/year (P = .023) and 0.9 +/- 1.9 (P = .008) mm/year during the first and second years, respectively. Enlargement of the distal neck during the observation period was more marked, with corresponding annual expansion rates of 1.7 +/- 2.9 mm/year (P < .001) and 1.9 +/- 2.5 (P < .001) mm/year. In 5 patients (14%), the minor diameter of the distal neck was at least 6 mm larger than the preimplant diameter of the graft. Migration of the distal attachment system was observed in 3 of these 5 patients. Expansion rates did not have a statistically significant correlation with initial neck size, endograft dimensions, aneurysm size change, presence of endoleak, or attachment system fracture. CONCLUSIONS: Aortic neck enlargement was observed for at least 2 years after endovascular grafting. Close patient follow-up remains mandatory in lieu of the potential risk of late failure as a result of continued aortic expansion. The relative contribution of device design to this phenomenon will need to be defined.

Aged↗
PubMed1997

Characterization of single-cell migration using a computer-aided fluorescence time-lapse videomicroscopy system.

Single-cell assays of cell migration, while yielding dynamic measurements of cell position and morphology, are predominantly limited by the time required for data collection and analysis. Computer-aided fluorescence time-lapse videomicroscopy (CAFTiV) was developed in order to facilitate the tracking and rapid examination of large numbers of motile cells. The system combines time-lapse videomicroscopy with epifluorescence capability, which allows full automation of image capture, sorting, and analysis due to the low background in the fluorescence images. Utilizing the CAFTiV system, data analysis time was reduced from over 125 h to less than 1 labor minute. In addition, fluorescence imaging permits cell tracking in small-volume chambers (<100 microL), which is useful should the addition of expensive reagents be required. It is anticipated that the ability to characterize both biochemical and biophysical properties responsible for cell movement will be enhanced by this methodology.

Cell Movement↗