PubMed Health⌕ Search

Biomedical subjects

G W Stone

Publications and source records attributed to G W Stone.

At least 55 records · Page 3Linked to original sources
PubMed2000

Clinical outcomes following "rescue" administration of abciximab in patients undergoing percutaneous coronary angioplasty.

Pre-intervention administration of abciximab in patients at "high risk" for coronary angioplasty has been shown to reduce acute and long-term cardiac outcomes. The role of intra-procedural ("rescue") administration of abciximab has not been fully elucidated. We assessed the clinical outcomes associated with rescue administration of abciximab during complex percutaneous coronary interventions. We studied in-hospital and long-term (1-year) outcomes (death, myocardial infarction and target lesion revascularization) of 298 consecutive patients (78% male; age, 62 +/- 11 years; 83% with acute coronary syndrome) treated with abciximab for thrombus-containing lesions, sub-optimal angioplasty results, procedural dissections or other complications. Stents were used in 73% of procedures. Procedural success was 97.0% and overall major in-hospital complication rate was 3.0% (death, 1.3%; Q-wave myocardial infarction, 0.7%; and emergent bypass surgery, 1.0%). Most frequent angiographic complications included visible thrombus (17%), dissections (17%), threatened closure (7%), and distal embolization (7%). In-hospital non-Q wave myocardial infarction (defined as CK-MB 5 times normal) occurred in 31.0%. Out-of-hospital to one-year events included death (1.7%), Q-wave myocardial infarction (2.7%), and target lesion revascularization (15.1%); cardiac event-free survival was 82.9%. We conclude that rescue administration of abciximab is associated with relatively low in-hospital complications and favorable long-term outcome in patients with sub-optimal angioplasty results and/or procedure-related complications, although peri-procedural non-Q wave myocardial infarction rate is high. A clinical and cost-effective comparison between provisional and rescue administration of abciximab may be warranted.

Abciximab↗
PubMed1999

Coronary angioplasty with or without stent implantation for acute myocardial infarction. Stent Primary Angioplasty in Myocardial Infarction Study Group.

BACKGROUND: Coronary-stent implantation is frequently performed for treatment of acute myocardial infarction. However, few studies have compared stent implantation with primary angioplasty alone. METHODS: We designed a multicenter study to compare primary angioplasty with angioplasty accompanied by implantation of a heparin-coated Palmaz-Schatz stent. Patients with acute myocardial infarction underwent emergency catheterization and angioplasty. Those with vessels suitable for stenting were randomly assigned to undergo angioplasty with stenting (452 patients) or angioplasty alone (448 patients). RESULTS: The mean (+/-SD) minimal luminal diameter was larger after stenting than after angioplasty alone (2.56+/-0.44 mm vs. 2.12+/-0.45 mm, P<0.001), although fewer patients assigned to stenting had grade 3 blood flow (according to the classification of the Thrombolysis in Myocardial Infarction trial) (89.4 percent, vs. 92.7 percent in the angioplasty group; P=0.10). After six months, fewer patients in the stent group than in the angioplasty group had angina (11.3 percent vs. 16.9 percent, P=0.02) or needed target-vessel revascularization because of ischemia (7.7 percent vs. 17.0 percent, P<0.001). In addition, the combined primary end point of death, reinfarction, disabling stroke, or target-vessel revascularization because of ischemia occurred in fewer patients in the stent group than in the angioplasty group (12.6 percent vs. 20.1 percent, P<0.01). The decrease in the combined end point was due entirely to the decreased need for target-vessel revascularization. The six-month mortality rates were 4.2 percent in the stent group and 2.7 percent in the angioplasty group (P=0.27). Angiographic follow-up at 6.5 months demonstrated a lower incidence of restenosis in the stent group than in the angioplasty group (20.3 percent vs. 33.5 percent, P<0.001). CONCLUSIONS: In patients with acute myocardial infarction, routine implantation of a stent has clinical benefits beyond those of primary coronary angioplasty alone.

Angioplasty, Balloon, Coronary↗
PubMed1999

In-hospital and long-term results of stent deployment compared with balloon angioplasty for treatment of narrowing at the saphenous vein graft distal anastomosis site.

Disease at the distal anastomosis site of saphenous vein grafts (SVGs) has been successfully treated with balloon angioplasty, with a lower restenosis rate than at sites of the aortoostial or proximal portion of the SVG. The role of stents for these lesions has not been well defined. To compare the in-hospital and long-term outcome of patients who underwent treatment at this site by either balloon angioplasty or tubular stent implantation, we studied 182 consecutive patients who underwent balloon angioplasty and 77 patients who underwent stenting between January 1994 and August 1997. Baseline clinical characteristics for both groups were similar. Angiographically, SVG stenoses treated with stents were older, longer in lesion length, and more restenotic. The in-hospital outcome was similar for both groups, with 98% procedural success rates and 1% major ischemic complications. Long-term follow-up was obtained for 93% of the patients, for an average of 17 +/- 14 months. The mortality rates were similar for patients who underwent balloon angioplasty and stenting (11.6% vs 13%, p = NS). The Q-wave myocardial infarction rates were also similar (1% vs 0%, p = NS). There was a trend toward a higher rate of target lesion revascularization in the balloon angioplasty group (25% vs 14%, p = 0.058). We conclude that percutaneous revascularization of the SVG distal anastomosis site by either balloon angioplasty or stenting can be performed with a high rate of procedural success and favorable in-hospital and long-term outcomes. Stent deployment may further improve the long-term outcome of these patients by reducing the need for repeat revascularization.

Aged↗
PubMed1999

Creatine kinase-MB enzyme elevation following successful saphenous vein graft intervention is associated with late mortality.

BACKGROUND: Although the risk for development of creatine kinase (CK-MB) elevation after saphenous vein graft (SVG) intervention is high, its prognostic significance remains unknown. This study evaluated the impact of periprocedural CK-MB elevation on late clinical events following successful SVG angioplasty. METHODS AND RESULTS: We studied 1056 consecutive patients with successful (defined by angiographic success and absence of major complications) intervention of 1693 SVG lesions. These patients were grouped as normal CK-MB (n=556), minor CK-MB rise (CK-MB 1 to 5 times normal, n=339), and major CK-MB rise (CK-MB >5 times normal, n=161). There were no differences in major clinical events at 30-day follow-up among the 3 groups. However, 1-year mortality was 4.8%, 6.5%, and 11. 7%, respectively, P<0.05 (ANOVA). Even within a population without any intraprocedure or in-hospital complications (n=727, 69% of the overall cohort), 1-year mortality remained significantly higher with CK-MB elevation: 2.4%, 5.5%, and 10.7%, respectively, P<0.05 (ANOVA). Multivariate analysis revealed major CK-MB elevation as the strongest independent predictor of late mortality (odds ratio 3.3, with 95% CI 1.7 to 6.2), followed by diabetes mellitus (odds ratio 2. 6, with 95% CI 1.5 to 4.5). CONCLUSIONS: Major CK-MB elevation occurs after 15% of otherwise successful SVG interventions and is associated with increased late mortality.

Aged↗
PubMed1999

Cardiac troponin I levels and clinical outcomes in patients with acute coronary syndromes: the potential role of early percutaneous revascularization.

OBJECTIVES: To establish the role of early catheter-based coronary intervention among patients sustaining acute coronary syndromes (ACS) stratified according to admission plasma troponin I (Tn-I) levels. BACKGROUND: The impact of early revascularization strategy on the clinical outcomes in patients with ACS stratified by plasma Tn-I levels has not been established. METHODS: In-hospital complications and long-term outcomes were assessed in 1,321 consecutive patients with non-ST elevation ACS undergoing early (within 72 h) catheter-based coronary interventions. Patients were grouped according to admission Tn-I levels. Group I (n = 1,099) had no elevated plasma Tn-I (<0.15 ng/ml), Group II (n = 95) had Tn-I level between 0.15 to 0.45 ng/ml and Group III (n = 127) had Tn-I >0.45 ng/ml. In-hospital composite cardiac events (death, Q-wave MI, urgent in-hospital revascularization) and 8 months clinical outcomes (death, MI, repeat revascularization or any cardiac event) were compared between the three groups. RESULTS: The rate of in-hospital composite cardiac events was 6.1% among patients with Tn-I >0.45 ng/ml, 1.0% in patients with Tn-I between 0.15-0.45 ng/ml and 3.1% in patients without elevated admission Tn-I (p = 0.09 between groups). There was no difference in hospital mortality (p = 0.25). At eight months of follow-up, there was no difference in out-of-hospital death (3.5%, 3.8% and 1.8%, p = 0.17, respectively), MI (2.6%, 3.8% and 2.9%, p = 0.94) or target lesion revascularization (9.0%, 8.3% and 11.5%, p = 0.47), and cardiac event-free survival was also similar between groups (p = 0.66). By multivariate analysis, Tn-I >0.45 ng/ml was independently associated with in-hospital composite cardiac events [odds ratio (OR) = 2.4, p = 0.04] but not with out-of-hospital clinical events up to eight months. CONCLUSIONS: In patients with ACS, early (within 72 h) catheter-based coronary intervention may attenuate the adverse prognostic impact of admission Tn-I elevation during eight months of follow-up despite a trend towards increased in-hospital composite cardiac events.

Aged↗
PubMed1999

Angiographic patterns of in-stent restenosis: classification and implications for long-term outcome.

BACKGROUND: The angiographic presentation of in-stent restenosis (ISR) may convey prognostic information on subsequent target vessel revascularizations (TLR). METHODS AND RESULTS: We developed an angiographic classification of ISR according to the geographic distribution of intimal hyperplasia in reference to the implanted stent. Pattern I includes focal (< or =10 mm in length) lesions, pattern II is ISR>10 mm within the stent, pattern III includes ISR>10 mm extending outside the stent, and pattern IV is totally occluded ISR. We classified a total of 288 ISR lesions in 245 patients and verified the angiographic accuracy of the classification by intravascular ultrasound. Pattern I was found in 42% of patients, pattern II in 21%, pattern III in 30%, and pattern IV in 7%. Previously recurrent ISR was more frequent with increasing grades of classification (9%, 20%, 34%, and 50% for classes I to IV, respectively; P=0.0001), as was diabetes (28%, 32%, 39%, and 48% in classes I to IV, respectively; P<0.01). Angioplasty and stenting were used predominantly in classes I and II, whereas classes III and IV were treated with atheroablation. Final diameter stenosis ranged between 21% and 28% (P=NS among ISR patterns). TLR increased with increasing ISR class; it was 19%, 35%, 50%, and 83% in classes I to IV, respectively (P<0.001). Multivariate analysis showed that diabetes (odds ratio, 2.8), previously recurrent ISR (odds ratio, 2. 7), and ISR class (odds ratio, 1.7) were independent predictors of TLR. CONCLUSIONS: The introduced angiographic classification is prognostically important, and it may be used for appropriate and early patient triage for clinical and investigational purposes.

Angioplasty, Balloon, Coronary↗
PubMed1999

Preintervention arterial remodeling as an independent predictor of target-lesion revascularization after nonstent coronary intervention: an analysis of 777 lesions with intravascular ultrasound imaging.

BACKGROUND: Pathological and intravascular ultrasound (IVUS) studies have documented arterial remodeling during atherogenesis. However, the impact of this remodeling process on the long-term outcome after percutaneous intervention is unknown. METHODS AND RESULTS: We used preintervention IVUS to define positive and negative/intermediate remodeling in a total of 777 lesions in 715 patients treated with nonstent techniques. Positive remodeling (lesion external elastic membrane area greater than average reference) was present in 313 lesions; intermediate/negative remodeling (lesion external elastic membrane area less than or equal to reference) was present in the other 464. Baseline clinical and angiographic characteristics were similar, except for a slightly higher percentage of insulin-dependent diabetic patients (10.2% versus 6.1%; P=0.054) in the negative/intermediate-remodeling group. Angiographic success and in-hospital and short-term complications were comparable in the 2 groups. There was no significant correlation between remodeling (as a continuous variable) and final lumen area (r=0.06) or final lesion plaque burden (r=0.17). At 18+/-13 months of clinical follow-up, both groups had similar rates of death and Q-wave myocardial infarction: 3.4% and 2.5% for the negative/intermediate-remodeling group versus 2.7% and 2.7% for the positive-remodeling group. However, the target-lesion revascularization (TLR) rate was 20.2% for the negative/intermediate-remodeling group versus 31.2% for the positive-remodeling group (P=0.007), and remodeling, as a continuous variable, was strongly correlated with probability of TLR (P=0.0001). By multivariable logistic regression analysis, diabetes (OR=2.3), left anterior descending artery location (OR=1.8), and remodeling (OR=5.9) were independent predictors of TLR. CONCLUSIONS: Positive lesion-site remodeling is associated with a higher long-term TLR after a nonstent interventional procedure. Thus, long-term clinical outcome appears to be determined in part by preintervention lesion characteristics.

Aged↗
PubMed1999

Clinical and angiographic follow-Up after primary stenting in acute myocardial infarction: the Primary Angioplasty in Myocardial Infarction (PAMI) stent pilot trial.

BACKGROUND: Restenosis has been reported in as many as 50% of patients within 6 months after PTCA in acute myocardial infarction (AMI), which necessitates repeat target-vessel revascularization (TVR) in approximately 20% of patients during this time period. Routine (primary) stent implantation after PTCA has the potential to further improve late outcomes. METHODS AND RESULTS: Primary stenting was performed as part of a prospective study in 236 consecutive patients without contraindications who presented with AMI of <12 hours' duration at 9 international centers. A mean of 1.4+/-0.7 stents were implanted per patient (97% Palmaz-Schatz) at 17.3+/-2.4 atm. During a clinical follow-up period of 7.4+/-2.6 months, death occurred in 4 patients (1.7%), reinfarction occurred in 5 patients (2.1%), and TVR was required in 26 patients (11.1%). By Cox regression analysis, small reference-vessel diameter and the number of stents implanted were the strongest determinants of TVR. Angiographic restenosis occurred in 27.5% of lesions. By multiple logistic regression analysis, the number of stents implanted and the absence of thrombus on the baseline angiogram were independent determinants of binary restenosis. CONCLUSIONS: A strategy of routine stent implantation during mechanical reperfusion of AMI is safe and is associated with favorable event-free survival and low rates of restenosis compared with primary PTCA alone.

Angioplasty, Balloon, Coronary↗
PubMed1999

Long-term outcome after primary angioplasty: report from the primary angioplasty in myocardial infarction (PAMI-I) trial.

OBJECTIVES: This study sought to compare the two-year outcome after primary percutaneous coronary angioplasty or thrombolytic therapy for acute myocardial infarction. BACKGROUND: Primary angioplasty, that is, angioplasty without antecedent thrombolytic therapy, has been shown to be an effective reperfusion modality for patients suffering an acute myocardial infarction. This report reviews the two-year clinical outcome of patients randomized in the Primary Angioplasty in Myocardial Infarction trial. METHODS: At 12 clinical centers, 395 patients who presented within 12 h of the onset of myocardial infarction were randomized to undergo primary angioplasty (195 patients) or to receive tissue-type plasminogen activator (t-PA) (200 patients) followed by conservative care. Patients were followed by physician visits, phone call, letter and review of hospital records for any hospital admission at one month, six months, one year and two years. RESULTS: At two years, patients undergoing primary angioplasty had less recurrent ischemia (36.4% vs. 48% for t-PA, p = 0.026), lower reintervention rates (27.2% vs. 46.5% for t-PA, p < 0.0001) and reduced hospital readmission rates (58.5% vs. 69.0% for t-PA, p = 0.035). The combined end point of death or reinfarction was 14.9% for angioplasty versus 23% for t-PA, p = 0.034. Multivariate analysis found angioplasty to be independently predictive of a reduction in death, reinfarction or target vessel revascularization (p = 0.0001). CONCLUSIONS: The initial benefit of primary angioplasty performed by experienced operators is maintained over a two-year follow-up period with improved infarct-free survival and reduced rate of reintervention.

Angioplasty, Balloon, Coronary↗
PubMed1999

Primary mechanical reperfusion in acute myocardial infarction: the United States experience.

Achievement of infarct-related artery (IRA) patency with thrombolytic agents has improved the clinical outcome of patients with acute myocardial infarction (MI). Primary angioplasty (PTCA) for direct IRA reperfusion may further improve patient outcome by overcoming several limitations of thrombolytic therapy, e.g. by decreasing the risk of haemorrhagic stroke, increasing the achievement of brisk antegrade flow, decreasing the risk of IRA reocclusion, and allowing early identification of patients who need surgical revascularization. In the PAMI-1 randomized trial, primary PTCA was superior to thrombolytic therapy. The GUSTO-IIb angioplasty substudy supported the same conclusion but with a narrower margin of benefit from PTCA. In order to further improve the outcome of primary mechanical reperfusion, routine intra-aortic balloon pump (IABP) insertion in high-risk MI patients and primary stenting have been evaluated. In PAMI-2, there was no major clinical benefit in routine IABP insertion during primary PTCA in high-risk patients. In contrast, primary stenting appears to offer significant advantages over PTCA, especially by decreasing the need for subsequent IRA revascularization procedures as shown in the recent PAMI Stent Randomized Trial. Adjunctive pharmacotherapy with potent antiplatelet agents in acute MI is being evaluated both in combination with thrombolytic therapy, and with primary PTCA and stenting. Finally, meaningful consideration of cost-effectiveness and health policy guidelines is warranted to optimize the appropriate management of MI patients in the current era, given the increasingly complex and expensive therapeutic strategies available.

Angioplasty, Balloon, Coronary↗
PubMed1998

Acute results, complications, and effect of lesion characteristics on outcome with the solid-state, pulsed-wave, mid-infrared laser angioplasty system: final multicenter registry report. Holmium:YAG Laser Multicenter Investigators.

BACKGROUND AND OBJECTIVE: The solid-state, mid-infrared holmium:YAG laser (2.1 microm wavelength) is a relatively new percutaneous device that has recently been evaluated in a multicenter study. Because of its unique wavelength and photoacoustic effects on atherosclerotic plaques, this laser may be useful in treatment of symptomatic patients with coronary artery disease. This study sought to evaluate the safety and efficacy of mid-infrared laser angioplasty in the treatment of coronary artery lesions. PATIENTS AND METHODS: Laser angioplasty was performed on 2,038 atherosclerotic lesions in 1,862 consecutive patients with a mean age of 61 +/- 11 years. Clinical indications included unstable angina (69%), stable angina (20%), acute infarction (6%), and positive exercise test (5%). Complex lesion morphology included eccentricity (62%), thrombus (30%), total occlusion (27%), long lesions (14%), and saphenous vein grafts (11%). RESULTS: This laser catheter alone successfully reduced stenosis (>20%) in 87% of lesions. With adjunct balloon angioplasty, 93% procedural success was achieved. The presence of thrombus within the target lesion was a predictor of procedural success (OR = 2.0 [95% confidence interval 2.0, 4.0], P = .04). Bifurcation lesions (OR = 0.5 [95% confidence interval 0.2, 1.0], P = .05) and severe tortuosity of the treated vessel (OR = 0.4 [95% confidence interval 0.2, 0.9], P = .02) were identified as significant predictors of decreased laser success. Calcium within the lesion was associated with reduced procedural success (OR = 0.57 [95% confidence interval 0.34, 0.97], P = .03), and calcified lesions required significantly more energy pulses than noncalcified lesions (119 +/- 91 pulses vs. 101 +/- 86 pulses, respectively, P = .0002). Complications included in-hospital bypass surgery 2.5%, Q-wave myocardial infarction 1.2%, and death 0.8%. Perforation occurred in 2.2% of patients; major dissection in 5.8% of patients, and spasm in 12% of patients. No predictor of major complications was identified. Six-month angiographic restenosis was documented in 54% of patients, and clinical restenosis occurred in 34% of patients. CONCLUSION: Mid-infrared laser has a safety profile similar to that of other debulking devices. This laser may be useful in select patients presenting with acute ischemic syndromes associated with intracoronary thrombus; however, like other coronary lasers, it is limited by the need for adjunctive balloon angioplasty and/or stenting to achieve adequate final luminal diameter. No beneficial effects on reducing 6-month restenosis rates were observed.

Aluminum Silicates↗
PubMed1998

Extensive direct-tandem organization of a long repeat DNA sequence on the Y chromosome of chinook salmon (Oncorhynchus tshawytscha).

A long repetitive DNA sequence (OtY8) has been cloned from male chinook salmon and its genomic organization has been characterized. The repeat has a unit length of 8 kb and is present approximately 300 times per diploid male nucleus. All internal fragments within the 8-kb repeat segregate from father to son, suggesting that the entire repeat unit is located on the Y chromosome. The organization of this sequence into an 8-kb repeat unit is restricted to the Y chromosome, as are several male-specific repeat subtypes identified on the basis of restriction-site variation. The repeat possesses only weak internal sequence similarities, suggesting that OtY8 has not arisen by duplication of a smaller repeat unit, as is the case for other long tandem arrays found in eukaryotes. Based on a laddered pattern arising from partial digestion of genomic DNA with a restriction enzyme which cuts only once per repeat unit, this sequence is not dispersed on the Y chromosome but is organized as a head-to-tail tandem array. Pulse-gel electrophoresis reveals that the direct-tandem repeats are organized into at least six separate clusters containing approximately 12 to 250 copies, comprising some 2.4 Mb of Y-chromosomal DNA in total. Related sequences with nucleotide substitutions and DNA insertions relative to the Y-chromosomal fragment are found elsewhere in the genome but at much lower copy number and, although similar sequences are also found in other salmonid species, the amplification of the repeat into a Y-chromosome-linked tandem array is only observed in chinook salmon. The OtY8 repetitive sequence is genetically tightly associated with the sex-determination locus and provides an opportunity to examine the evolution of the Y chromosome and sex determination process in a lower vertebrate.

Animals↗
PubMed1998

Prospective, multicenter study of the safety and feasibility of primary stenting in acute myocardial infarction: in-hospital and 30-day results of the PAMI stent pilot trial. Primary Angioplasty in Myocardial Infarction Stent Pilot Trial Investigators.

OBJECTIVES: The goals of this study were to examine the safety and feasibility of a routine (primary) stent strategy in acute myocardial infarction (AMI). BACKGROUND: Limitations of reperfusion by primary percutaneous transluminal coronary angioplasty (PTCA) in AMI include in-hospital recurrent ischemia or reinfarction in 10% to 15% of patients, restenosis in 37% to 49% and late infarct-related artery reocclusion in 9% to 14%. By lowering the residual stenosis and sealing dissection planes created by PTCA, primary stenting may further improve short- and long-term outcomes after mechanical reperfusion. METHODS: Three hundred twelve consecutive patients treated with primary PTCA for AMI at nine international centers were prospectively enrolled. After PTCA, stenting was attempted in all eligible lesions (vessel size 3.0 to 4.0 mm; lesion length < or = 2 stents; and the absence of giant thrombus burden after PTCA, major side branch jeopardy or excessive proximal tortuosity or calcification). Patients with stents were treated with aspirin, ticlopidine and a 60-h tapering heparin regimen. RESULTS: Stenting was attempted in 240 (77%) of 312 patients, successfully in 236 (98%), with Thrombolysis in Myocardial Infarction grade 3 flow restored in 230 patients (96%). Patients with stents had low rates of in-hospital death (0.8%), reinfarction (1.7%), recurrent ischemia (3.8%) and predischarge target vessel revascularization for ischemia (1.3%). At 30-day follow-up, no additional deaths or reinfarctions occurred among patients with stents, and target vessel revascularization was required in only one additional patient (0.4%). CONCLUSIONS: Primary stenting is safe and feasible in the majority of patients with AMI and results in excellent short-term outcomes.

Aged↗