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Biomedical subjects

G New

Publications and source records attributed to G New.

At least 19 recordsLinked to original sources
PubMed2005

The foundation and launch of the Melbourne Interventional Group: a collaborative interventional cardiology project.

The Melbourne Interventional Group (MIG) is a voluntary collaborative venture of interventional cardiologists practicing at 12 major public and private hospitals in Victoria, designed to record data pertaining to percutaneous coronary interventions (PCI) and perform long-term follow-up. The potential advantages of collaboration involve large-scale analysis of current interventional strategies (e.g. drug-eluting stents, evaluation of new technologies and cost-effective analysis), provide a basis for multi-centred clinical trials and allow comparison of clinical outcomes with cardiac surgery. The established registry documents demographic, clinical and procedural characteristics of consecutive patients undergoing PCI and permits analysis of those characteristics at 30 days and 12 months. The registry is co-ordinated by the Centre of Clinical Research Excellence (CCRE), a research body within the Department of Epidemiology and Preventive Medicine (Monash University, Melbourne). The eventual goal of MIG is to provide a contemporary appraisal of Australian interventional cardiology practice, with opportunities to improve in-hospital and long-term outcomes of patients with coronary artery disease.

Angioplasty, Balloon, Coronary↗
PubMed2001

Effect of the distal-balloon protection system on microembolization during carotid stenting.

BACKGROUND: The distal-balloon protection system is being evaluated for its efficacy in preventing embolic neurological events during carotid stenting (CAS). We sought to determine the effect of this system on the frequency of Doppler-detected microembolic signals (MES) during CAS. METHODS AND RESULTS: Using transcranial Doppler, we compared the frequency of MES during CAS in 2 groups: 39 patients without distal protection and 37 who used the distal-balloon protection system (GuardWire). There were no significant differences in the clinical or angiographic characteristics between the 2 groups. Three phases with increased MES counts were identified during unprotected CAS; these were stent deployment, predilation, and postdilation (75+/-57, 32+/-36, and 27+/-25 METS, respectively). The distal-balloon protection significantly reduced the frequency of MES during CAS (MES counts: 164+/-108 in the control versus 68+/-83 in the protection group; P=0.002), particularly during these 3 phases. MES in the protection group were detected predominantly during sheath placement, guidewire manipulation, and distal-balloon deflation. CONCLUSION: Three phases with increased MES counts were identified during unprotected CAS (eg, stent deployment, predilation, and postdilation). The distal-balloon protection system significantly reduced the frequency of MES during CAS, particularly during these 3 phases.

Aged↗
PubMed2001

Immediate and late clinical outcomes of carotid artery stenting in patients with symptomatic and asymptomatic carotid artery stenosis: a 5-year prospective analysis.

BACKGROUND: Carotid stenting is a less invasive percutaneous procedure than carotid endarterectomy for the treatment of carotid stenosis. Reports suggest that it can be performed with periprocedural complication rates similar to those of carotid endarterectomy. The purpose of this study was to determine short- and long-term outcomes in the largest prospective cohort of carotid stenting patients. METHODS AND RESULTS: This study followed 528 consecutive patients (604 hemispheres/arteries) undergoing carotid stenting. There was a 0.6% (n=3) fatal stroke rate and 1% (n=5) nonstroke death rate at 30 days. The major stroke rate was 1% (n=6), and the minor stroke rate was 4.8% (n=29). The overall 30-day stroke and death rate was 7.4% (n=43). Over the 5-year study period, the 30-day minor stroke rate improved from 7.1% (n=7) for the first year to 3.1% (n=5) for the fifth year (P:<0.05 for trend). The best predictor of 30-day stroke and death was age >/=80 years. After the 30-day period, the incidence of fatal and nonfatal stroke was 3.2% (n=31). On Kaplan-Meier analysis, the 3-year freedom from ipsilateral or fatal stroke was 92+/-1%. CONCLUSIONS: Experience from a single group of operators demonstrates that carotid stenting can be performed with an acceptable 30-day complication rate. Late follow-up also demonstrates a low rate of fatal and nonfatal stroke. These results suggest that carotid stenting may be comparable to carotid endarterectomy, and it underscores the clinical equipoise and premise for the National Institute of Health-supported, randomized Carotid Revascularization Endarterectomy Versus Stent Trial comparing carotid stenting with carotid endarterectomy.

Age Factors↗
PubMed2001

Validity of duplex ultrasound as a diagnostic modality for internal carotid artery disease.

There is an increasing trend to rely on duplex ultrasound rather than angiography to measure an internal carotid artery stenosis. The aim of this study was to determine the validity of ultrasound assessment of carotid stenosis performed in community based vascular laboratories. We compared ultrasound with angiography in 225 patients referred to us for carotid intervention. Mild lesions were diagnosed by ultrasound with a sensitivity of 54%, specificity of 89%, and a positive predictive value of 89% compared with angiography. Severe lesions had a sensitivity of 93%, a specificity of 67%, and a positive predictive value of 45%. Receiver operator characteristic curves demonstrated the optimal ultrasound cut-off value of 66% stenosis as a predictor of >60% stenosis measured angiographically, is associated with a false positive rate of 38%, and a false negative rate of 9%. Similarly, if a cut-off of 76% on ultrasound is used to predict >70% stenosis measured angiographically, it would be associated with a 29% false positive rate and a false negative rate of 11%. Despite the value of non-invasive testing for carotid disease, duplex ultrasonography performed in non-accredited and some accredited laboratories may produce highly variable results. Using ultrasound as the sole diagnostic test to determine the severity of a carotid stenosis may result in a high number of inappropriate operations and a large proportion of patients who may not be offered treatment due to false negative diagnoses.

Aged↗
PubMed2001

Integrated minimally invasive approaches for the treatment of atherosclerotic vascular diseases: Hybrid procedures.

Patients may develop simultaneous symptoms of atherosclerotic vascular disease from different arterial beds. A concurrent minimally invasive approach to the management of these clinical situations may be an advantage over conventional surgical procedures. This study describes two separate case series of patients undergoing coronary/peripheral (n = 38) and peripheral/peripheral procedures (n = 10). Technical and clinical success was achieved in all patients. There were two periprocedural complications (retroperitoneal bleed and septicemia) in the coronary/peripheral series and no complications in the peripheral/peripheral series. We also present five case reports to illustrate the utility of hybrid procedures in various clinical settings. This study suggests that the use of simultaneous or sequential minimally invasive procedures appears to be a safe and feasible strategy for the treatment of patients with symptoms from more than one vascular bed. Cathet Cardiovasc Intervent 2001;52:154-161.

Aged↗
PubMed2001

Subarachnoidal hemorrhage following carotid stenting with the distal-balloon protection.

A 61-year-old man underwent carotid stenting with the distal-balloon protection system for symptomatic carotid artery stenosis. During the procedure, progressive elevation of the systolic blood pressure occurred, reaching a peak of 220 mm Hg immediately following deflation of the distal balloon. This was associated with severe headaches and progressive deterioration in the mental status to a coma. Head CT scan showed massive subarachnoidal hemorrhage contralateral to the stented side and a secondary intracerebral hemorrhage. Despite immediate successful blood pressure control, his condition deteriorated and he died 2 days later.

Carotid Artery, Internal↗
PubMed2001

Procedural safety and short-term outcome of ambulatory carotid stenting.

BACKGROUND AND PURPOSE: Ambulatory procedures increase patient comfort and enhance cost-effectiveness. We sought to determine the feasibility and safety of ambulatory carotid stenting. METHODS: A selected group of patients was admitted and discharged the same day after the carotid stenting procedure. Immediate and short-term outcomes are reported. RESULTS: A total of 98 ambulatory carotid stenting procedures (98 hemispheres in 92 patients) were performed. There were 66 men (72%), and the mean age was 70+/-9 years. Of the patients, 28% had neurological symptoms related to the treated artery within 3 months before the procedure. Sixteen percent of the patients had prior carotid endarterectomy, 4% had prior ipsilateral neck radiation, and 8% had complete occlusion of the contralateral internal carotid artery. Successful access site hemostasis was ensured in all patients with suture-mediated vascular closure devices in 96 (98%) and manual compression in 2. Clinical follow-up was available for 96% of the patients at a mean time of 6+/-4 months. There were no neurological events, deaths, repeated procedures, or major access site complications. CONCLUSIONS: Ambulatory carotid stenting is both safe and feasible. This approach will enhance the applicability of the procedure by increasing patient comfort and potentially reducing procedural costs.

Aged↗
PubMed2001

Embolization via collateral circulation during carotid stenting with the distal balloon protection system.

PURPOSE: To describe a potential route for embolization to the middle cerebral artery (MCA) during carotid stenting with the distal balloon protection system. CASE REPORT: An 82-year-old man with symptomatic severe carotid artery stenosis underwent elective carotid stenting with distal-balloon protection. Despite complete occlusion of the distal internal carotid artery, frequent emboli were detected in the ipsilateral MCA by transcranial Doppler (TCD) during the procedure. Intracranial angiography, performed during the distal-balloon protection, revealed filling of the MCA through collaterals from the ipsilateral external carotid artery. The procedure was successfully completed without complications. The patient remains asymptomatic at 6 months. CONCLUSIONS: During carotid stenting with distal-balloon protection, asymptomatic embolization into the ipsilateral MCA may occur through collateral circulation. The clinical significance of these emboli is uncertain.

Aged↗
PubMed2001

Carotid stenting with distal-balloon protection via the transbrachial approach.

PURPOSE: To document the feasibility of brachial artery access for carotid stenting with distal-balloon protection of the internal carotid artery (ICA). TECHNIQUE: Via percutaneous access to the brachial artery, a large double-curve catheter is advanced into the aortic arch over a hydrophilic guidewire to cannulate the left common carotid artery. Following sheath exchange, a GuardWire distal-protection balloon is positioned within the left ICA distal to the stenosis. The lesion is dilated, followed by deployment and dilation of a self-expanding stent. Transcranial Doppler monitoring shows only scarce microembolic signals during the procedure. CONCLUSIONS: Carotid stenting with distal balloon protection via the brachial artery appears feasible as an alternative to standard femoral access.

Aged↗
PubMed2001

Carotid angioplasty with stenting in post-carotid endarterectomy restenosis.

Recurrent stenosis post-carotid endarterectomy (CEA) is not a solitary or unusual phenomenon. Compared to the initial CEA, the reoperation is often more technically challenging and frequently results in local and neurological complications. Carotid artery angioplasty with stenting (CAS) is currently being investigated as an alternative to carotid endarterectomy. In our study, ninety-nine patients underwent CAS in 110 arteries. Procedural success was 99% (109/110). Our results show that CAS treatment in post-CEA restenosis, especially with improved technique and distal protection, is safe with a low neurological complication rate, without any "local" complications and without any cranial nerve palsies. This study suggests that the future primary mode of treatment of post-CEA restenosis might be carotid stenting rather than surgery.

Aged↗
PubMed2000

Procedural costs of digital vs. analog archiving of diagnostic cardiac catheterizations.

The use of digital technology in the cardiac catheterization laboratory is expanding at a rapid pace. The cost-effectiveness of this new technology is yet to be proven. The aims of this study were to determine the direct cost differences of digital versus analog media (CDs) for the storage of diagnostic cardiac catheterizations and to explore the factors influencing these differences. Procedural costs of all diagnostic angiograms (n = 109), from three physicians, performed in an analog catheterization laboratory (room A) and a digital catheterization laboratory (room C) were compared during a 9-month period. The mean procedural cost was higher in room A than in room C ($1,102 vs. $1,087, P < 0.001). This cost difference was eliminated when recording media costs were excluded from analysis ($1,079 vs. $1,080, P = 0.931). Therefore, we conclude there is a procedural cost savings in a cardiac catheterization room that uses digital CDs versus cineangiogram film as the archival media. Cathet. Cardiovasc. Intervent. 49:246-250, 2000.

Cardiac Catheterization↗
PubMed2000

Long-term oestrogen treatment does not alter systemic arterial compliance and haemodynamics in biological males.

BACKGROUND: Studies have shown that chronic oestrogen treatment improves both lipid profile and vascular reactivity in postmenopausal women, in whom it also appears to have a beneficial effect on vascular haemodynamics and compliance. Whether oestrogen has a similar effect in men is unknown. OBJECTIVE: To determine whether long-term oestrogen treatment alters arterial compliance and haemodynamics in biological males. METHODS: We compared the effects of chronic oestrogen treatment on blood pressure, heart rate and arterial compliance in 21 male-to-female transsexuals prescribed long-term oestrogen treatment with those in 20 age-matched healthy males. Systemic arterial compliance was assessed using the 'area method', by the simultaneous measurement of aortic flow and driving pressure. RESULTS: Mean systemic arterial compliance was similar in transsexuals and age-matched males (mean +/- SE 0.66 +/- 0.06 ml/mmHg compared with 0.58 +/- 0.05 ml/mmHg, P = 0.34). These results did not differ after the exclusion of transsexuals with coronary risk factors or vascular disease. Heart rate (67 +/- 2 beats/min compared with 64 +/- 3 beats/min, P = 0.41), systolic blood pressure (119 +/- 3 mmHg compared with 119 +/- 2 mmHg, P = 0.95), pulse pressure (55 +/- 3 mmHg compared with 50 +/- 2 mmHg, P = 0.13), diastolic blood pressure (64 +/- 2 mmHg compared with 69 +/- 2 mmHg, P = 0.06) and mean arterial pressure (84 +/- 2 mmHg compared with 89 +/- 2 mmHg, P = 0.09) were also similar at baseline between the two groups. Serum testosterone (an index of oestrogen treatment) was markedly suppressed in the transsexuals compared with the males (0.8 +/- 0.5 nmol/l compared with 25.3 +/- 12.6 nmol/l, P < 0.0001). Univariate analysis revealed that the best predictors of arterial compliance were the pulse pressure (rs = -0.41, P = 0.02) and the systolic blood pressure (rs = -0.35, P = 0.02). On multivariate analysis, the best combination of predictors of compliance were the pulse pressure, testosterone and low-density lipoprotein cholesterol concentrations (R2 = 0.29, P = 0.01). CONCLUSIONS: Although previous evidence suggests chronic oestrogen treatment can improve endothelium-dependent vasodilatation and favourably alter the lipid profile in biological males, these changes are not reflected in changes in systemic arterial compliance. Changes in arterial compliance may not be central to the beneficial effects of oestrogen on vascular function, at least in males.

Adult↗
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↗
PubMed2000

Techniques of carotid artery stenting: the state of the art.

The technique of carotid stenting has undergone significant refinement since its introduction and continues to improve as experience with the procedure matures and more suitable equipment becomes available. Improved stent designs and the utilization of cerebral protection devices are expected to significantly impact on the technique, its ultimate outcomes, and widespread application. In using the currently available technology for carotid stenting, patient selection and meticulous attention to procedural details are very important in minimizing embolic events. In this article, we provide a comprehensive practical discussion of the state-of-the-art carotid stenting techniques that have allowed us to maintain low event rates.

Carotid Arteries↗
PubMed2000

Carotid artery stenting: technical considerations.

BACKGROUND AND PURPOSE: Carotid endarterectomy (CEA) is one of the most frequently performed operations in the United States. To offer patients a less invasive means to achieve the same goal, carotid artery stenting (CAS) is investigated as an alternative treatment to CEA. METHODS: Three hundred ninety patients underwent CAS, with 451 vessels treated. CAS was performed using a coaxial system with a 7F 90-cm sheath for predilation, stent placement, and stent dilation. Pretreatment antiplatelet therapy was administered. We currently practice same-day admissions and 23-hour discharges. RESULTS: The technical success rate was 98%. The 30-day mortality/morbidity rates were as follows: death, 1.7% (two [0.5%] neurologic and five [1.2%] systemic] major strokes, 0.9% (two of four were related to the intervention); minor strokes, 5.5%. Among 25 patients who suffered minor strokes, 14 achieved complete recovery. On an annual basis, the incidence of minor stroke declined from 6.8% (1994-1995), to 5.8% (1995-1996), 5.3% (1996-1997), and then 4% (1997-1998), with no major strokes or neurologic deaths occurring during the 1997 to 1998 period. CONCLUSION: CAS is an effective treatment for carotid stenosis. With proper selection of patients and meticulous technique, complication rates compare favorably with those of CEA.

Adult↗
PubMed1999

Metabolic vasodilation in the human forearm is preserved in hypercholesterolemia despite impairment of endothelium-dependent and independent vasodilation.

OBJECTIVE: Hypercholesterolemia has been shown to impair endothelium-mediated, nitric oxide (NO)-dependent responses to acetylcholine (ACh), serotonin, substance P and flow-mediated dilation. We have recently shown that NO contributes to metabolic vasodilation in the human forearm. We sought to determine whether metabolic vasodilation is impaired in healthy subjects with hypercholesterolemia. METHODS: We compared the forearm blood flow (FBF) responses to isotonic exercise, ACh and the endothelium-independent vasodilator sodium nitroprusside in young, otherwise healthy volunteers with hypercholesterolemia and controls before and after the NO inhibitor NG-monomethyl-L-arginine (L-NMMA). FBF was measured using venous occlusion plethysmography. Hypercholesterolemic (n = 20) and control (n = 20) subjects were age- and gender-matched. RESULTS: Total cholesterol (6.9 +/- 0.3 vs. 4.6 +/- 0.1 mmol/l, P < 0.0001), low density lipoprotein (4.9 +/- 0.4 vs. 2.7 +/- 0.1 mmol/l, P < 0.001) and triglyceride (1.3 +/- 0.2 vs. 0.8 +/- 0.1 mmol/l, P = 0.005) levels were higher in the hypercholesterolemic group. Basal FBF and resistance were similar in the two groups. Hypercholesterolemia impaired the peak FBF response to ACh (11.1 +/- 1.9 vs. 17.6 +/- 2.2 ml/100 ml/min, P = 0.03), and reduced the peak response to sodium nitroprusside (6.0 +/- 0.4 vs. 8.1 +/- 0.6 ml/100 ml/min, P < 0.01). However, hypercholesterolemia did not affect peak hyperemic FBF (13.1 +/- 1.0 vs. 13.2 +/- 1.0 ml/100 ml/min, P = 1.0) or the FBF volume repayment during the 1 or 5 min after exercise. Resting FBF was reduced by L-NMMA to a similar degree (by 33% vs. 40%, P = 0.17) in both groups. Although L-NMMA reduced peak hyperemic FBF (by 16% vs. 17%, P = 0.93) and the volume repaid after exercise in both groups, there were no differences between the two groups. CONCLUSIONS: Exercise-induced metabolic vasodilation is in part dependent on NO release. Hypercholesterolemia impairs NO-mediated vasodilation, but is not associated with a reduction in exercise-induced hyperemia. This may indicate that multiple compensatory mechanisms are operative in skeletal muscle metabolic vasodilation.

Acetylcholine↗