Technological devices in peripheral percutaneous interventions.

New innovations and novel approaches to peripheral arterial occlusive disease have brought enormous benefits to the vascular patient. Diseases that were once manageable only by surgical intervention are now easily and successfully treated by minimally invasive procedures. While the early days of percutaneous intervention were filled with inventions of new devices, today the focus centers on using modern technology and manufacturing to further improve upon these devices. Advances in guidewires and catheters have allowed us to visualize and treat lesions in nearly any vessel, and technology is guiding us towards specialized applications for specific lesions in specific vessels. However, one of the big hurdles remaining in treating arterial occlusive diseases is the rate of restenosis and the need for reinterventions. The location and architecture of these vessels make them uniquely difficult to treat, and call for new technology to address these challenges. Current developments of drug-eluting and bioabsorbable stents are at the forefront of new advancements specifically directed at improving current patency and restenosis rates; perhaps the next step in percutaneous intervention will rely on nanotechnology and the molecular surface engineering that may achieve a new era of devices that are able to target specific cell ligands or proteins to prevent the inflammatory and proliferative response from vessels. The present review will focus on the current literature regarding technological devices in peripheral percutaneous interventions and clinical applications. Future advancements in materials engineering and biotechnology will continue to improve the current standard of percutaneous intervention for peripheral arterial occlusive diseases.

Computational study of haemodynamic effects of entry- and exit-tear coverage in a DeBakey type III aortic dissection: technical report.

OBJECTIVES: Outcome prediction in DeBakey Type III aortic dissections (ADs) remains challenging. Large variations in AD morphology, physiology and treatment exist. Here, we investigate if computational fluid dynamics (CFD) can provide an initial understanding of pressure changes in an AD computational model when covering entry and exit tears and removing the intra-arterial septum (IS). DESIGN: A computational mesh was constructed from magnetic resonance images from one patient (one entrance and one exit tear) and CFD simulations performed (scenario #1). Additional meshes were derived by virtually (1) covering the exit tear (false lumen (FL) thrombus progression) (scenario #2), (2) covering the entrance tear (thoracic endovascular treatment, TEVAR) (scenario #3) and (3) completely removing the IS (fenestration) (scenario #4). Changes in flow patterns and pressures were quantified relative to the initial mesh. RESULTS: Systolic pressures increased for #2 (300 Pa increase) with largest inter-luminal differences distally (2500 Pa). In #3, false lumen pressure decreased essentially to zero. In #4, systolic pressure in combined lumen reduced from 2400 to 800 Pa. CONCLUSIONS: CFD results from computational models of a DeBakey type III AD representing separate coverage of entrance and exit tears correlated with clinical experience. The reported results present a preliminary look at a complex clinical problem.

Carotid artery stenting--current status and future directions.

Carotid endarterectomy has been the standard of therapy for carotid occlusive disease in stroke prevention. More recently, carotid angioplasty and stenting became an important alternative in the treatment of carotid occlusive disease. The widespread use of cerebral protection devices has substantially decreased the morbidity of the procedure. As the experience with carotid stenting increases, so does the enthusiasm for the potential of this minimally invasive carotid intervention to become the main treatment option for the high risk patients, as well as for the average asymptomatic patient. Although current available data indicate that the results regarding success and complication rates are similar between carotid stenting and endarterectomy, several prospective clinical trials are currently in progress to evaluate the efficacy of carotid artery stenting in different patient populations and definitively establish its role in the treatment of carotid disease. This paper reviews the current status of carotid stenting, including results from clinical trials, technical aspects and controversial issues and strategies to provide cerebral protection from embolization.

Embolus of surgical adhesive to the extremities causing acute ischemia: report of two cases.

We present 2 cases in which a surgical adhesive embolized to the extremities. In the first case an adhesive was successfully used in the repair of a DeBakey type I aortic dissection. The patient was seen 2 months postoperatively with acute lower extremity ischemia, and a large piece of adhesive was extracted from the iliac and femoral arteries at embolectomy. In the second case the adhesive was used to seal a pericardial patch during repair of a ventricular septal defect. This patient was seen 1 day postoperatively with acute arm ischemia, and the adhesive particle was extracted from the brachial artery during embolectomy.

Endovascular management of abdominal aortic aneurysms.

An estimated 1.5 million people in the United States have abdominal aortic aneurysms (AAAs) with more than 200000 American diagnosed each year. The natural history of AAAs is to expand and rupture, accounting for an estimated 15000 deaths per year. Thus, the major impetus for AAA repair is for prophylaxis against aneurysm-related death. The standard open surgical repair of AAAs is a well-established and durable procedure. However, as with all other major abdominal surgical operations, associated significant morbidity and mortality exist, along with prolonged recovery and various late complications. Furthermore, both mortality and morbidity increase significantly with advanced patient age and associated co-morbid disease states. Endovascular AAA repair using covered stent-grafts offers a significantly less invasive alternative to conventional open-surgical repair. A considerable reduction in hospital stay has been demonstrated, with early return to preoperative levels of activity. Patients previously considered unsuitable for open repair can often receive treatment for aneurysms with endovascular techniques. Current estimates are that more than 1/2 all infrarenal AAAs will be repaired using endovascular approach in the future. Despite the minimally-invasiveness of this new treatment, there are unanswered questions as to the durability and efficacy of devices, which results in concerns about their ability to successfully protect the patient from subsequent rupture. Three devices are commercially available and have been extensively used for implantation in the United States with a 4th device recently receiving approval from the Food and Drug Administration (FDA). In this review article, endovascular management of AAAs with these devices is described, as are the design and deployment techniques of the currently available endografts.

Epidural analgesia in patients with chronic obstructive pulmonary disease undergoing transperitoneal abdominal aortic aneurysmorraphy--a multi-institutional analysis.

INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) are more likely to develop pulmonary morbidity following major abdominal surgery. The purpose of this study was to examine the utility of epidural analgesia in patients with COPD who underwent elective transperitoneal abdominal aortic aneurysm (AAA) repair. METHODS: During a 7-year period, all patients diagnosed with COPD undergoing elective AAA repair (n=425) from three hospitals were reviewed. Inclusion criteria were an FEV(1)/FVC ratio <75% and/or a PaCO(2)>45 mmHg. Clinical outcomes were compared between those who received epidural analgesia (epidural group) and those who did not (control group). Primary endpoints measured were duration of intubation, ICU stay, hospital days, and pulmonary complications. RESULTS: Strict inclusion criteria were met by 131 patients, which included 86 patients in the epidural group and 45 patients in the control group. When comparing the epidural vs. control group, the mean AAA size was 6.3+/-0.9 cm vs. 6.0+/-1.5 cm (NS), FEV(1) was 57.2+/-24.7% vs. 49.0+/-10.3% (NS), and the mean FEV(1)/FVC ratio was 52.0+/-11.4% vs. 50.6+/-6.7% (NS), respectively. The epidural group had a significantly lower incidence of post-operative ventilator dependency and ICU stay (p<0.05), as well as a decreased trend in pulmonary complications when compared to the control group. The overall hospital stay remained similar between the two groups. The relative risk of developing a pulmonary complication in the absence of epidural analgesia was 2.3. CONCLUSIONS: Perioperative epidural analgesia is beneficial in patients with COPD undergoing AAA repair by reducing both the post-operative ventilator duration and ICU stay. Epidural analgesia should be considered in all COPD patients undergoing elective transperitoneal AAA repair.

Surgical intervention for complications caused by femoral artery catheterization in pediatric patients.

PURPOSE: This study evaluated the risk factors and surgical management of complications caused by femoral artery catheterization in pediatric patients. METHODS: From January 1986 to March 2001, the hospital records of all children who underwent operative repairs for complications caused by femoral artery catheterization were reviewed. A prospective cardiac data bank containing 1674 catheterization procedures during the study period was used as a means of determining risk factors associated with iatrogenic femoral artery injury. RESULTS: Thirty-six operations were performed in 34 patients (age range, 1 week-17.4 years) in whom iatrogenic complications developed after either diagnostic or therapeutic femoral artery catheterizations during the study period. Non-ischemic complications included femoral artery pseudoaneurysms (n = 4), arteriovenous fistulae (n = 5), uncontrollable bleeding, and expanding hematoma (n = 4). Operative repairs were performed successfully in all patients with non-ischemic iatrogenic femoral artery injuries. In contrast, ischemic complications occurred in 21 patients. Among them, 14 patients had acute femoral ischemia and underwent surgical interventions including femoral artery thrombectomy with primary closure (n = 6), saphenous vein patch angioplasty (n = 6), and resection with primary anastomosis (n = 2). Chronic femoral artery occlusion (> 30 days) occurred in seven patients, with symptoms including either severe claudication (n = 4) or gait disturbance or limb growth impairment (n = 3). Operative treatments in these patients included ileofemoral bypass grafting (n = 5), femorofemoral bypass grafting (n = 1), and femoral artery patch angioplasty (n = 1). During a mean follow-up period of 38 months, no instances of limb loss occurred, and 84% of children with ischemic complications eventually gained normal circulation. Factors that correlated with an increased risk of iatrogenic groin complications that necessitated surgical intervention included age younger than 3 years, therapeutic intervention, number of catheterizations (>or= 3), and use of 6F or larger guiding catheter. CONCLUSION: Although excellent operative results can be achieved in cases of non-ischemic complications, acute femoral occlusion in children younger than 2 years often leads to less satisfactory outcomes. Operative intervention can provide successful outcome in children with claudication caused by chronic limb ischemia. Variables that correlated with significant iatrogenic groin complications included a young age, therapeutic intervention, earlier catheterization, and the use of a large guiding catheter.

Colonic necrosis subsequent to catheter-directed thrombin embolization of the inferior mesenteric artery via the superior mesenteric artery: a complication in the management of a type II endoleak.

The optimal management of endoleaks after endovascular repair of abdominal aortic aneurysms remains to be established. In this report, we describe a persistent side-branch, or type II, endoleak 1 year after endograft implantation treated with catheter-directed embolization of the aneurysm sac and the inferior mesenteric artery via the superior mesenteric artery, with embolization agents including thrombin, lipiodol, and gelfoam powder. Shortly after the embolization procedure, colonic necrosis developed in the patient, manifested by peritonitis, which necessitated a partial colectomy. This case underscores the devastating complication of colonic ischemia as a result of catheter-directed embolization of the inferior mesenteric artery in the management of an endoleak.

Intra-arterial thrombin injection of an ascending aortic pseudoaneurysm complicated by transient ischemic attack and rescued with systemic abciximab.

Thrombin injection as a means of inducing thrombus formation has recently received wide attention as an alternative treatment for pseudoaneurysm. We present a case of a 67-year-old man in whom a large mycotic pseudoaneurysm developed in the ascending aorta because of sternal osteomyelitis and mediastinitis after coronary artery bypass grafting. Transcatheter intra-arterial thrombin injection was performed, and it successfully induced pseudoaneurysm thrombosis. However, the procedure was complicated by a sudden transient ischemic attack caused by thrombus propagation into the cerebral circulation. Complete thrombus dissolution in the cerebral circulation with the resolution of neurologic symptoms was achieved by means of intravenous abciximab.

Sloughing of the scrotal skin and impotence subsequent to bilateral hypogastric artery embolization for endovascular aortoiliac aneurysm repair.

Sloughing of the scrotal skin is an extremely rare event due to pelvic ischemia. We report herein one case of scrotal skin sloughing and impotence after bilateral hypogastric artery embolization for endoluminal aortoiliac aneurysm repair. Postoperative penile plethysmography demonstrated a 75% reduction in the penile brachial index, suggesting that pelvic ischemia is the main culprit for this complication. The devastating morbidity in our patient underscores the importance of maintaining pelvic collateral circulation when planning for endovascular aortoiliac aneurysm repair.

Early experience with the bifurcated Excluder endoprosthesis for treatment of the abdominal aortic aneurysm.

PURPOSE: This report describes our initial experience with the modular, bifurcated Excluder endoprosthesis and its safety and efficacy in the primary endovascular repair of infrarenal abdominal aortic aneurysms (AAAs). METHODS: AAAs (mean diameter, 58.2 +/- 14.3 mm) were repaired in 19 patients with this device between March 1999 and January 2000. The mean age of patients was 71.8 +/- 8.4 years (range, 57-86 years). This modular device was inserted through an 18F introducer sheath placed in one femoral artery, and the contralateral artery was cannulated with a 12F introducer sheath. All procedures were performed in a standard operating room with angiographic capabilities. RESULTS: Endograft deployment was successful in all patients. The average surgical time was 135 +/- 37 minutes, with a mean blood loss of 229 +/- 138 mL. In eight patients, the use of either aortic or iliac extenders was required for enhanced sealing or additional length. An external iliac artery dissection occurring at the time of endograft insertion was successfully treated with a Wallstent. Type II leaks initially found to be present by means of intraoperative completion angiography had spontaneously thrombosed by the 1-month follow-up computed tomography scan. There was one perioperative death (5.3%). Complications included superficial wound infections (n = 3) and a nonfatal myocardial infarction (n = 1). The mean length of hospital stay was 2.9 +/- 1.2 days, and only six patients required intensive care. Endoleaks were seen in four patients (21%) by means of the 30-day computed tomography scan; three of these endoleaks had spontaneously sealed at the time of the 6-month follow-up examination (5.5% 6-month endoleak rate). Aneurysm size did not increase in the patients with leaks. CONCLUSION: The Excluder endoprosthesis was an effective means of excluding an infrarenal AAA from the systemic circulation in this selected group of patients. The smaller sheath sizes may increase the pool of potential candidates. Further study of this device is warranted, and continued assessment of the long-term durability of the device will be necessary.

Detection of isolated hook fractures 36 months after implantation of the Ancure endograft: a cautionary note.

Two cases of delayed (36-month) Ancure hook fracture are reported in patients who experienced a decrease in aneurysm size and no evidence of endoleak. Both devices used redesigned hooks and are otherwise identical to those devices currently used in clinical practice. Notably, hook fractures were not visualized on all abdominal radiographic views, nor were they noted on the final "institutional" report by the reviewing radiologist. Careful clinical follow-up with multiple-view abdominal radiographs remains essential for all patients treated with an endovascular graft, with particular attention directed to the integrity of the metal components. The broader clinical significance of this observation with respect to the Ancure endograft remains to be defined.

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.

Evaluation of thrombolysis in a porcine model of chronic deep venous thrombosis: an endovascular model.

PURPOSE: The advancement of catheter-based interventions for vascular recanalization has underscored the need for an experimental animal model of vascular thrombosis that can be used for the evaluation of interventional therapies. In this model, a porcine model of deep venous thrombosis with a novel endovascular technique was described, and the efficacy of thrombolytic therapy with urokinase was evaluated. METHODS: An endovascular device that consisted of a tapered polytetrafluoroethylene graft attached within a self-expanding nitinol stent was delivered to bilateral common iliac veins in 20 pigs. Venous thrombosis occurred as a result of flow stasis created by the intrastent stenosis. Catheter-directed pulse-spray thrombolysis with urokinase (250,000 units) and heparin (5000 IU) was performed on one limb while the contralateral limb received control saline solution. Thrombolysis was performed in 1 hour (n = 4), 8 hours (n = 4), 3 days (n = 4), 7 days (n = 4), and 14 days (n = 4) after the stent-graft deployment. Venography and intravascular ultrasound were used to evaluate the efficacy of thrombolysis. Light microscopy was used for histologic analysis of the thrombus. RESULTS: Complete thrombolysis was achieved in groups with deep vein thrombosis that were younger than 1 day. Angioplasty of the tapered stent-grafts in the completely thrombolysed iliac vein was successful in restoring venous flow. The efficacy of thrombolysis in 3-day, 7-day, and 14-day groups was 86% +/- 7%, 73% +/- 13%, and 42% +/- 23%, respectively. The thrombolytic efficacy was enhanced to 92% +/- 16% and 86% +/- 18% (P <.05) in 3-day and 7-day groups, respectively, when doses of the pulse-spray thrombolysis were doubled. Increased dosages of the thrombolytic agent, however, did not significantly enhance the thrombus dissolution in the 14-day group. CONCLUSION: The thrombolytic efficacy of urokinase correlated with the chronicity of deep venous thrombosis in our model. An increased dose of urokinase may be used to enhance the efficacy of thrombolysis in a 1-week-old thrombus.

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.

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.

Endoluminal stent placement and coil embolization for the management of carotid artery pseudoaneurysms.

PURPOSE: To present a series of carotid artery pseudoaneurysms treated successfully using an endovascular approach. METHODS: From April 1995 to November 1999, 5 patients with neurological symptoms not explained by computed tomography of the head were identified by carotid angiography as having internal carotid artery (ICA) pseudoaneurysms. Three patients had sustained blunt trauma, and 2 had previous elective carotid endarterectomies for atherosclerotic disease. The time between injury and treatment ranged from 3 days to 10 years. The patients were treated with endovascular stent placement for exclusion of the pseudoaneurysm, followed by filling of the cavity with multiple detachable coils. Patients were maintained on oral antiplatelet agents or anticoagulant therapy after the procedure. RESULTS: Primary technical success was 100%. No patient suffered permanent neurological sequelae. Postprocedure angiography demonstrated a patent ICA in all cases, with complete obliteration of the pseudoaneurysm. At a mean 8.4-month follow-up (range 2-21), all patients remained symptom free; angiograms in 3 patients at a mean 11.7 months demonstrated continued ICA patency. One patient had a 60% focal narrowing of the distal common carotid artery, which was treated successfully with balloon dilation and stenting. CONCLUSIONS: Endovascular treatment of carotid artery pseudoaneurysms is a useful alternative to standard surgical repair. This modality avoids the necessity for surgical exposure at the skull base with its inherent morbidity.

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.

Effects of nicotine and cotinine on porcine arterial endothelial cell function.

UNLABELLED: BACKGROUND. There has been a significant amount of research on the effects of nicotine on vascular biology; however, little is known about the effects of cotinine, the metabolic product of nicotine. This study used a novel vascular perfusion system to study the effects of nicotine and cotinine on the vascular endothelial cell function. METHODS: Porcine common carotid arteries were cultured in a novel vascular perfusion system with nicotine or cotinine or as controls. After 24 h, vessels were precontracted with norepinephrine and subsequently relaxed with acetylcholine. Vessel diameters were recorded and analyzed. After culture, samples were taken for en face, immunohistochemistry, and RT-PCR for eNOS. Porcine coronary arteries were incubated as controls or with nicotine or cotinine and tested on a myograph system to measure contraction and relaxation. RESULTS: Porcine carotid arteries treated with nicotine and cotinine showed a 27.2% and a 41.2% reduction in endothelial-dependent relaxation, respectively, as compared to control vessels (P<0.05). Rings of coronary arteries treated with nicotine relaxed similarly to control rings while cotinine-treated rings failed to relax to endothelial-dependent stimulation. RT-PCR for eNOS mRNA showed a 23. 2 and a 24.1% reduction in eNOS expression for nicotine- and cotinine-treated vessels, respectively (P<0.01). Additionally, immunohistochemical staining for eNOS showed less dense staining on nicotine- and cotinine-treated vessels as compared to controls. En face preparations showed normal endothelial cell morphology in all groups, but cell density decreased slightly in vessels treated with nicotine and cotinine. CONCLUSION: These results indicate that cotinine may have even more effect on the impairment of endothelial-dependent vasorelaxation than nicotine for the regulation of vessel tone in porcine carotid and coronary arteries.