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R S Stack

Publications and source records attributed to R S Stack.

At least 19 recordsLinked to original sources
PubMed2001

Intra-arterial thrombolysis (reteplase) and ReoPro for subacute thrombosis of the distal aorta accomplished by radial arterial access: the radial-kissing-thrombolytic technique.

A 33-year-old woman with subacute thrombosis of the distal aorta after aorto-bi-iliac stenting had local thrombolysis with reteplase in conjunction with systemic abciximab. The infusion was given as a bolus and then continuously for 14 hr by radial artery access with two selective kissing catheters. Patency of the stented segments was achieved with this technique in conjunction with resolution of her clinical symptoms.

Abciximab↗
PubMed2001

Primary renal artery stenting: characteristics and outcomes after 363 procedures.

BACKGROUND: Stenting improves the acute results of percutaneous balloon angioplasty for atherosclerotic renal artery stenosis. Predictors of benefit and angiographic restenosis are not well understood. We describe the technical and clinical success of renal artery stenting in a large consecutive series of patients with hypertension or renal insufficiency. We identify clinical, procedural, and anatomic factors that might influence outcome, restenosis, and survival. METHODS: Primary renal artery stenting was performed in 300 consecutive patients who underwent 363 stent procedures in 358 arteries. Angiograms were analyzed quantitatively. Clinical and angiographic follow-up data are available after a median of 16.0 months. RESULTS: At baseline, 87% of patients had hypertension, and 37% had chronic renal insufficiency. The mean age was 70 years (interquartile range 63.1-74.6) years. The stenosis was unilateral in 49% and bilateral in 48% and involved a solitary functioning kidney in 3.6%. The stenting procedure was successful in all attempts. There were no procedural deaths or emergency renal surgical procedures. Postprocedure azotemia was seen in 45 of 363 (12%) procedures but persisted in only 6 patients (2%), all of whom had baseline renal insufficiency. Systolic and diastolic blood pressures were significantly reduced (systolic blood pressure from 164.0 +/- 28.7 to 142.4 +/- 19.1 mm Hg, P <.001). At follow-up, 70% of patients had improved blood pressure control regardless of renal function. In patients with baseline renal insufficiency, 19% had improvement in serum creatinine levels at follow-up, 54% had stabilization, and 27% had deterioration. Follow-up mortality was 10% and was predicted by baseline creatinine levels (odds ratio 1.72 for each 1 mg/dL creatinine increment, 95% confidence interval 1.13-2.49) and extent of coronary artery disease (odds ratio 1.66 for each diseased coronary artery, 95% confidence interval 1.03-2.67). Angiographic restenosis was found in 21% of 102 patients overall and was less common (12%) in arteries with a reference caliber >4.5 mm (P <.01 vs caliber <4.5 mm). Neither poststenotic dilation nor severity of angiographic stenosis predicted clinical outcome. CONCLUSIONS: Primary renal artery stenting can be performed safely with nearly uniform technical success. The majority of patients with hypertension or renal insufficiency derive benefit. Follow-up mortality is 5-fold higher in patients with baseline renal insufficiency. Clinical and angiographic features did not predict blood pressure or renal functional outcome. Restenosis is more common in renal arteries with a reference caliber less than 4.5 mm.

Aged↗
PubMed2000

Comparison of medicine alone, coronary angioplasty, and left internal mammary artery-coronary artery bypass for one-vessel proximal left anterior descending coronary artery disease.

Despite the deleterious and sometimes catastrophic consequences of proximal left anterior descending (LAD) artery occlusion, there is a paucity of data to guide the treatment of patients with such disease. Our aim was to describe outcomes with medical therapy, angioplasty, or left internal mammary artery (LIMA) bypass grafting in patients with 1-vessel, proximal LAD disease. We retrospectively analyzed prospectively collected data from 1,188 patients first presenting only with proximal LAD disease at 1 center over 9 years. We assessed the rates of death, acute myocardial infarction, and repeat intervention by initial treatment over a median 5.7 years of follow-up. Patients undergoing angioplasty or LIMA bypass were more often men and had progressive or unstable angina; those receiving medical therapy had a lower median ejection fraction. Both revascularization procedures offered slightly better adjusted survival versus medicine (hazard ratio for angioplasty, 0.82; 95% confidence interval, 0.60 to 1.11; hazard ratio for bypass, 0.74; 95% confidence interval, 0.44 to 1.23). Bypass, but not angioplasty, was associated with significantly fewer composite end point events (death, infarction, or reintervention, p <0.0001), and angioplasty was associated with a higher composite event rate than bypass or medical therapy (p <0.0001 and p = 0.0003, respectively). The initial advantages of bypass and medicine over angioplasty diminished over time; angioplasty became more advantageous than medicine after 1 year (p = 0.05) and not significantly different from bypass. Treatment of 1-vessel, proximal LAD disease with medicine, angioplasty, or UMA bypass resulted in comparable adjusted survival. However, LIMA bypass alone reduced the long-term incidence of infarctions and repeat procedures.

Aged↗
PubMed2000

Local delivery of heparin post-PTCA: a multicenter randomized pilot study.

Bailout stenting for major dissection and threatened closure has high rates of ischemic complications. We performed a randomized trial of local heparin delivery using the infusion sleeve before bailout stenting for suboptimal angioplasty results. In phase I, 20 patients were randomized to local delivery with either 40- or 100-psi infusion pressure. In phase II, 37 patients were randomized to local delivery at 100 psi or standard therapy. Local delivery succeeded in all but one patient; overall there was no significant worsening of intimal dissection. One patient treated with 100-psi drug infusion suffered a perforation after stent placement. There were no significant differences in the composite endpoint of death, MI, CABG, urgent repeat angioplasty, and stent thrombosis at 30 days (21% vs. 0%; P = 0.18). At 6 months, the rates of myocardial infarction in phase II were 27% with local delivery vs. 10% with standard treatment (P = 0.4). Local heparin delivery in dissected vessels may be associated with increased complications and should be approached with caution.

Aged↗
PubMed2000

Safety, efficacy, and durability of carotid artery stenting for restenosis following carotid endarterectomy: a multicenter study.

PURPOSE: To present the results of a multicenter registry established to collect data on carotid stent procedures in patients with restenosis following carotid endarterectomy. METHODS: The procedural details, outcomes, and late follow-up results were collected from 14 centers in the United States. Thirty-day and late stroke and death rates were analyzed. RESULTS: Three hundred and thirty-eight patients (201 men; 71 +/- 8 years) underwent carotid stenting in 358 arteries. The average duration from carotid endarterectomy was 5.5 +/- 7.3 years. Sixty-one percent of the patients were asymptomatic. The overall 30-day stroke and death rate was 3.7%. The minor stroke rate was 1.7% (6/358), and the major nonfatal stroke rate was 0.8% (3/358). The fatal stroke rate was 0.3% (1/358), and the nonstroke-related death rate was 0.9% (3/338). There was 1 (0.3%) fatal and 1 (0.3%) nonfatal stroke during the follow-up period. The overall 3-year rate of freedom from all fatal and nonfatal strokes was 96% +/- 1% (+/- SE). CONCLUSIONS: Carotid artery stenting can be performed in patients with restenosis following carotid endarterectomy with 30-day complication rates comparable to those of most published studies on repeat carotid endarterectomy. Results of late follow-up suggest that this technique is durable and efficacious.

Aged↗
PubMed1999

Local drug delivery of argatroban from a polymeric-metallic composite stent reduces platelet deposition in a swine coronary model.

Thrombus formation after intracoronary stent implantation provides a stimulus for neointimal hyperplasia and if excessive can result in stent thrombosis. We tested the hypothesis that local delivery of an antithrombin drug from a polymeric-metallic stent inhibits platelet thrombus formation. An uncoated metal slotted tube, a jellyroll slotted metal stent with an Argatroban-loaded polymeric sleeve, and a jellyroll slotted metal stent with a drug-leached polymeric sleeve were randomly deployed into the coronary arteries of eight juvenile farm swine. Platelet deposition in the stented segments was determined at 2 hr using autologous 111Indium oxime-labeled platelets. Platelet deposition was significantly less in the Argatroban-loaded stents compared to the Argatroban-leached stents (1.40 x 10(8) platelets/cm2 vs. 26.8 x 10(8) platelets/cm2; P=0.005). When corrected for differences in the metal surface area exposed to blood, platelet deposition was significantly lower in the Argatroban-loaded stent (1.74+/-1.95 x 10(8)/cm2) compared to the Argatroban-leached stent (33.5+/-39.1 x 10(8)/cm2; P=0.005) and the uncoated metal stent (36.2+/-73.3 x 10(8)/cm2; P=0.006). In this coronary stent thrombosis model Argatroban has local antithrombotic properties when delivered with a polymer-metallic stent. Improved polymeric designs may reduce risk of thrombus deposition at the site of stent implantation.

Animals↗
PubMed1999

Acute and long-term cost implications of coronary stenting.

OBJECTIVES: We compared the acute and one year medical costs and outcomes of coronary stenting with those for balloon angioplasty (percutaneous transluminal coronary angioplasty) in contemporary clinical practice. BACKGROUND: While coronary stent implantation reduces the need for repeat revascularization, it has been associated with significantly higher acute costs compared with coronary angioplasty. METHODS: We studied patients treated at Duke University between September 1995 and June 1996 who received either coronary stent (n = 384) or coronary angioplasty (n = 159) and met eligibility criteria. Detailed cost data were collected initially and up to one year following the procedure. Our primary analyses compared six and 12 month cumulative costs for coronary angioplasty- and stent-treated cohorts. We also compared treatment costs after excluding nontarget vessel interventions; after limiting analysis to those without prior revascularization; and after risk-adjusting cumulative cost estimates. RESULTS: Baseline clinical characteristics were generally similar between the two treatment groups. The mean in-hospital cost for stent patients was $3,268 higher than for those receiving coronary angioplasty ($14,802 vs. $11,534, p < 0.001). However, stent patients were less likely to be rehospitalized (22% vs. 34%, p = 0.002) or to undergo repeat revascularization (9% vs. 26%, p = 0.001) than coronary angioplasty patients within six months of the procedure. As such, mean cumulative costs at 6 months ($19,598 vs. $19,820, p = 0.18) and one year ($22,140 vs. $22,571, p = 0.26) were similar for the two treatments. Adjusting for baseline predictors of cost and selectively examining target vessel revascularization, or those without prior coronary intervention yielded similar conclusions. CONCLUSIONS: In contemporary practice, coronary stenting provides equivalent or better one-year patient outcomes without increasing cumulative health care costs.

Aged↗
PubMed1998

Acute hemodynamic changes during carotid artery stenting.

To determine the clinical significance of acute hemodynamic disturbances during stenting in the carotid sinus region, we assessed the relation between intraprocedural changes in heart rate (HR) and blood pressure (BP) and adverse neurologic and cardiac outcomes. Eighteen patients underwent carotid stenting with the Wallstent (Schneider Inc). Suitable candidates had at least 60% diameter stenosis of the carotid artery by angiography. Initial and nadir HR and BP were recorded during the predilatation, stent delivery, and postdilatation periods. Bradycardia was defined as HR < or =60 beats/min and hypotension as systolic BP < or =100 mm Hg. Nineteen Wallstents were successfully deployed in all 19 carotid arteries. Some degree of bradycardia or hypotension occurred in 68% of carotid stent procedures, but administration of vasoactive medications was necessary in only 7 patients (37%) with more persistent hemodynamic disturbances. Hypotension or the need for continuous vasopressor therapy was significantly more common during postdilatation (32%) than in the predilatation period (5%) (p = 0.02). Bradycardia was not reduced by prophylactic atropine. In 1 patient the hemodynamic response to stenting may have contributed to an adverse neurologic and cardiac outcome. Thus, despite frequent fluctuations in HR and BP, most carotid stenting procedures were performed with excellent overall results, even in patients at high risk.

Aged↗
PubMed1998

Local administration of L-703,081 using a composite polymeric stent reduces platelet deposition in canine coronary arteries.

We compared the effect on platelet deposition of the glycoprotein IIb/IIIa receptor antagonist L-703,081, administered locally via a drug delivery stent, with that of a standard metal stent in a canine coronary model. There was a significant reduction in platelet deposition using the L-703,081-impregnated stent compared with the bare metal stent. This study demonstrates an alternative route of delivery of GPIIb/IIIa antagonists with potential advantages over systemic administration.

Animals↗
PubMed1998

A randomized trial of vascular hemostasis techniques to reduce femoral vascular complications after coronary intervention.

This report details a prospectively randomized clinical trial comparing mechanical clamp compression to hand applied pressure for attaining vascular hemostasis after coronary intervention. Effectiveness was determined by comparing the incidence of femoral vascular complications resulting from each of the 2 techniques. Eligible participants included 778 consecutive patients scheduled for percutaneous coronary intervention over an 8-month period. An unselected cohort of the eligible patients (n = 592), determined by the availability of cross-trained clinicians, underwent follow-up serial physical examinations by blinded observers for the duration of their hospital stay. A second, similarly determined cohort (n = 390), underwent color-duplex ultrasonography within 24 hours of sheath removal. Baseline demographic and clinical characteristics, sheath removal parameters, and subsequent outcomes were collected prospectively. The primary end point was a composite of ultrasound-defined femoral vascular complications: femoral artery thrombosis, echogenic hematoma, pseudoaneurysm, or arteriovenous fistulae formation. Complications diagnosed by physical examination constituted the second fundamental end point and included: persistent oozing, ecchymosis, hematoma, bruit, and pulsatile mass. Compared to manual compression, mechanical clamp hemostasis reduced the primary adverse end point by 63% (p = 0.041). Physical examination detected ecchymosis, oozing, and hematomas at equally high frequencies in the two cohorts. Although 65% of the patients in both treatment groups encountered at least one of these cosmetic complications, the diagnoses made by physical examination did not correlate with ultrasound-defined pathology. Multivariable stepwise logistic regression analysis identified a relationship of advanced age and lower body weight to vascular complications. Utilization of a mechanical clamp rather than conventional hand pressure to attain vascular hemostasis significantly reduces ultrasound-defined femoral vascular pathology. Discrepancies between physical examination and ultrasound diagnoses challenge the utility of clinical assessment alone and establish ultrasound as the diagnostic modality of choice.

Angioplasty, Balloon, Coronary↗
PubMed1998

Internal mammary artery graft angioplasty: acute and long-term outcome.

Secondary to the low attrition rate of internal mammary artery grafts, limited data are available on the clinical and angiographic outcome of patients who have undergone balloon angioplasty of an internal mammary artery stenosis. This study examined a consecutive series of 68 patients who underwent balloon angioplasty of an internal mammary artery graft over a 9-year period. Procedural success was achieved in 60 of 68 (88%) patients. The primary reason for procedural failure was extreme vessel tortuosity. There were no major in-hospital complications. Angiographic follow-up was obtained in 78% of the patients with an angiographic restenosis rate of 19%. The overall event-free survival in patients with an initially successful procedure was 92%. In conclusion, internal mammary artery balloon angioplasty has both an excellent initial success rate as well as a low incidence of restenosis and repeat target lesion revascularization.

Aged↗
PubMed1998

[General principles in treatment of urethral strictures].

This manuscript outlines the important points in the evaluation and treatment of urethral stricture disease. The algorithms described within are not presented as strict guidelines but rather are intended to give a logical thought progression which incorporates the basic principles of urethral reconstruction. It is important to determine the therapeutic goal before applying these principles. There are basically two arms of consideration, the first is to attempt to cure the patient of urethral stricture disease and the second is to simply manage the patient's urethral stricture disease without intent of cure. Applying the current knowledge of anatomy with modern tissue transfer techniques will achieve a highly successful, single stage reconstruction in most patients. Although approaching urethral stricture disease with the intent to cure is preferred, management may not be unreasonable in certain cases. Some patients have entensive co-morbidities or may prefer a trial of conservative measures before definitive treatment is undertaken. If the goal established is urethral reconstruction, the gold standard is to perform a single stage procedure that is highly successful and durable. Excision of the urethral stricture with primary anastomosis (EPA) represents this gold standard. However, ist application is limited by stricture location or length. An accurate evaluation of the stricture location, length, and associated spongiofibrosis is mandatory in forming viable options for repair. By exploiting the advantages of differing techniques, the proper course of action can be chosen which generally will solve even the most complex problem in one stage. The reconstructive surgeon come to the operative suite armed with the full knowledge and understanding of the principals and techniques which will result in a favorable outcome. It is not uncommon for intra-operative findings to guide the decision for the best alternative for urethral reconstruction. We also offer some helpful hints regarding positioning, sutures, exposure, and retractors.

Algorithms↗
PubMed1998

Kissing stents in the aortic bifurcation.

BACKGROUND: We report the first series of simultaneously delivered stents used to treat stenosis of the aortic bifurcation. Surgical treatment of aortoiliac occlusive disease carries up to a 3% mortality rate. Percutaneous balloon techniques to treat aortic bifurcation stenosis, although safer, are still associated with up to a 9% incidence of dissection, thrombosis, or significant residual stenosis. Kissing stent insertion should decrease the incidence of these complications. METHODS: Twenty patients underwent kissing stent insertion. Suitable candidates included patients with symptoms of lower limb ischemia and significant atherosclerotic lesions in both ostial common iliac arteries (n = 15) or with extremely complex single ostial iliac stenoses (n = 5). Palmaz stents were delivered simultaneously to both limbs of the aortic bifurcation. RESULTS: Kissing stent insertion was successfully performed in all 20 patients without acute complications. Mean percent stenosis decreased from 46.2%+/-24.8% to -6.8%+/-13.3% (P = .0001) in the right iliac artery, 42.3%+/-22.8% to -1.6% +/-18.1% (P = .0001) in the left iliac artery, and 19.1%+/-16.6% to 2.3%+/-16.4% (P= .0008) in the distal aorta. Intermittent claudication symptoms were improved in 18 (95%) of 19 patients with 12 (63%) of 19 patients becoming totally asymptomatic. The strongest predictor of clinical outcome after kissing stent insertion was the preprocedural extent of femoropopliteal disease: 8 (89%) of 9 patients with femoropopliteal narrowing <75% bilaterally became completely asymptomatic at follow-up compared with only 3 (30%) of 10 patients with more severe stenoses (P = .02). CONCLUSIONS: We have demonstrated in 20 patients that stenoses of the aortic bifurcation can be treated effectively with kissing stents with few serious adverse events.

Aged↗
PubMed1998

Progression of renal artery stenosis in patients undergoing cardiac catheterization.

BACKGROUND: Renal artery stenosis is potentially correctable by either revascularization surgery or percutaneous methods. However, appropriate use of these techniques has been hampered by a lack of data on the natural history of this disease. This study assesses the prevalence, risk factors for progression, and effect on renal function of angiographically demonstrated renal artery disease in patients undergoing cardiac catheterization. METHODS: The severity of renal artery stenosis was quantified in all patients who underwent abdominal aortography as part of a diagnostic cardiac catheterization study at Duke University Medical Center between January 1989 and February 1996. RESULTS: There were 14,152 patients in the study (mean age 61+/-12 years, 62% male). Normal renal arteries were identified in 12,543 (88.7%) patients, insignificant disease (<50% stenosis) in 1 or more vessels in 726 patients (5.1 %), and significant stenosis in 883 patients (6.3%). Significant bilateral renal artery stenosis was present in 178 patients (1.3%). By multivariate logistic regression, elevated serum creatinine level, coronary artery disease, peripheral vascular disease, hypertension, cerebrovascular disease, older age, female sex, and family history of coronary artery disease were identified as independent predictors of significant renal arterial disease. Disease progression was assessed in 1189 patients. Mean time between cardiac catheterizations was 2.6+/-1.6 years. Significant disease progression occurred in 133 patients (11.1 %). Independent predictors of disease progression were female sex, age, coronary artery disease at baseline, and time between baseline and follow-up. At follow-up, serum creatinine level was significantly higher in patients who demonstrated > or =75% stenosis in 1 or more vessels (mean creatinine level 141+114 micromol/L compared with those with insignificant disease (mean creatinine level 97+/-44 micromol/L (P= .01). CONCLUSIONS: Renal artery disease is frequently progressive in patients who undergo cardiac catheterization for investigation of coronary artery disease. Significant stenotic disease may develop over a short period despite evidence of normal renal arteries at prior catheterization.

Age Factors↗
PubMed1997

The natural history of single-vessel chronic coronary occlusion: a 25-year experience.

To determine the natural history of patients with a total occlusion of a single coronary artery, we searched the Duke Databank for Cardiovascular Disease to find all patients who underwent a first coronary angiogram >2 days after a symptomatic myocardial infarction between 1969 and 1994. Patients who underwent angiography >30 days after the acute event had a low risk of death in the first year (3%), and a proximal left anterior descending coronary occlusion did not confer substantially higher risk of death (4%). Patients undergoing angiography <30 days after the acute event had a higher mortality (5%), especially those with proximal left anterior descending occlusion (10%). The time from the acute event to angiography was a predictor of death (p = 0.04). Despite low 1-year mortality rates, patients with total occlusion of an isolated coronary vessel treated medically had substantial mortality, myocardial infarction, and revascularization rates over a long-term follow-up period.

Adult↗
PubMed1996

Relation between activated clotting time during angioplasty and abrupt closure.

BACKGROUND: The purpose of this study was to determine whether the degree of heparin anticoagulation during coronary angioplasty, as measured by the activated clotting time, is related to the risk of abrupt vessel closure. METHODS AND RESULTS: Sixty-two cases of in- and out-of-laboratory abrupt closure in patients in whom intraprocedure activated clotting times were measured were identified from a population of 1290 consecutive patients who underwent non-emergency coronary angioplasty. This group was compared with a matched control population of 124 patients who did not experience abrupt closure. Relative to the control population, patients who experienced abrupt closure had significantly lower initial (median, 350 seconds [25th to 75th percentile, 309 to 401 seconds] versus 380 seconds [335 to 423 seconds], P = .004) and minimum (345 seconds [287 to 387 seconds] versus 370 seconds [321 to 417 seconds], P = .014) activated clotting times. Higher activated clotting times were not associated with an increased likelihood of major bleeding complications. Within this population, a strong inverse linear relation existed between the activated clotting time and the probability of abrupt closure. CONCLUSIONS: This study demonstrates a significant inverse relation between the degree of anticoagulation during angioplasty and the risk of abrupt closure. A minimum target activated clotting time could not be identified; rather, the higher the intensity of anticoagulation, the lower the risk of abrupt closure.

Aged↗
PubMed1995

Differential expression of tissue factor protein in directional atherectomy specimens from patients with stable and unstable coronary syndromes.

BACKGROUND: Tissue factor (TF) is a cell membrane-associated protein that catalyzes the rate-limiting step of the extrinsic coagulation pathway, which is the major source of thrombin production in vivo. To explore the potential role that TF may play in ischemic coronary syndromes, directional coronary atherectomy specimens were tested for the presence of TF protein using immunohistochemical techniques. METHODS AND RESULTS: Frozen sections from atherectomy specimens in 61 patients were examined for TF expression using an IgG murine monoclonal antibody against human TF. Patients were classified according to their admission diagnosis as having either an unstable or a stable coronary syndrome. An unstable coronary syndrome was defined as either angina pectoris occurring at rest or post-myocardial infarction (< 1 week) angina. Stable coronary syndromes included patients with stable, progressive, and new-onset (< 6 weeks) angina without rest pain. TF was detected in 15 (43%) of 35 patients with unstable coronary syndromes versus only 3 (12%) of 26 patients with stable coronary syndromes (odds ratio, 5.7; 95% confidence interval, 1.3 to 24.3; P = .018). Within the subgroup of patients with unstable coronary syndromes, TF was detected in 14 (60%) of 25 patients with de novo lesions versus only 1 (10%) of 10 patients with a restenosis lesion (P < .02). An additional 8 patients with stable coronary syndromes due to a restenosis lesion were also negative for TF. Therefore, the overall incidence of TF expression was only 6% (1 of 18) in restenosis lesions compared with 33% (14 of 43) in de novo lesions (P < .03). CONCLUSIONS: This study provides the first description of TF protein expression in human coronary artery lesions in vivo. Tissue factor was readily detected in de novo lesions in patients with unstable coronary syndromes, suggesting a role for TF in the pathogenesis of this disease process. Conversely, TF was rarely detected in patients with restenosis lesions even if the resulting clinical presentation was an unstable coronary syndrome. These results may have implications for the management of patients with unstable angina from de novo lesions and patients with ischemic symptoms from a restenosis lesion.

Angina Pectoris↗