PubMed Health⌕ Search

Biomedical subjects

Gregg W Stone

Publications and source records attributed to Gregg W Stone.

At least 37 records · Page 2Linked to original sources
PubMed2006

Procedural implications of intravascular ultrasound morphologic features of chronic total coronary occlusions.

Although the success rates of percutaneous coronary intervention of chronic total occlusions (CTOs) have improved, morphologic features are not well known. We analyzed experience at 4 centers where intravascular ultrasound (IVUS) was performed in 67 native artery CTO lesions (mean CTO duration 6.3 months) just after the lesion was crossed with a guidewire (n = 7) or after dilatation with a 1.5-mm (n = 46) or 2.0-mm (n = 14) balloon. IVUS detected calcium somewhere in the CTO in 96%; however, only 68% had mild calcium. IVUS identified a proximal end of the CTO in all lesions, but a distal end of the CTO in only 50%. An intramural hematoma was observed in 34% of CTOs, suggesting that the guidewire frequently entered the medial space during successful recanalization. CTOs were longer, vessel area was smaller, and total calcium index was greater in lesions with hematomas (p = 0.003, 0.05, and 0.03, respectively). Inadequate reflow after the procedure was observed in 9% and was associated with longer lesions and intralesional calcium. CTO length as measured with angiography was shorter than the length as measured with IVUS (p = 0.02). Calcium was detected on the angiogram in 61% (p = 0.054 vs IVUS). Most typical angiographic findings associated with a low rate of procedural success were not associated with different IVUS morphologies. In conclusion, CTO lesions had multiple small calcium deposits, intramural hematomas were common and were indicative of guidewire penetration into the medial space during the CTO procedure, especially in long calcified lesions in smaller vessels, and inadequate reflow after the procedure was correlated with more complex CTO morphology.

Aged↗
PubMed2006

Intravascular ultrasonic differences between aorto-ostial and shaft narrowing in saphenous veins used as aortocoronary bypass grafts.

Previous studies have reported differences in interventional complication rates that depend on saphenous vein graft (SVG) lesion location. However, little is known about morphologic differences between lesions in different SVG locations. We evaluated preintervention intravascular ultrasound (IVUS) images of 75 de novo SVG lesions (aorto-ostial, n = 15; shaft, n = 60) in 63 patients. IVUS data were measured at the minimal lumen area and at 2 proximal and 2 distal references. Positive remodeling was defined as a lesion site SVG area that was larger than the average of the 2 distal references. Shaft lesions more often contained soft plaque (60.0% vs 26.7%, p = 0.02). Minimal lumen areas were identical (4.5 +/- 2.9 vs 4.3 +/- 1.5 mm2, p = 0.3); however, plaque burden at the minimal lumen area was greater in shaft locations (79.3 +/- 9.4% vs 72.1 +/- 9.2%, p = 0.01). The frequency of positive remodeling in shaft versus aorto-ostial lesions was 70.2% versus 26.7% (p = 0.002). SVG shaft lesions have more soft plaque and larger plaque burdens and undergo positive remodeling more frequently than SVG aorto-ostial lesions. These IVUS differences may account for some of the location-specific differences in interventional complications.

Aged↗
PubMed2006

An outline for public registration of clinical trials evaluating medical devices.

Public registration of clinical trials is fundamentally important to the integrity of the medical device development process. In addition to fulfilling obligations to those study volunteers, a complete record of trial results provides the general public, clinical community, and medical device manufacturers with a more accurate understanding as to how a specific therapeutic should be used. Although the issues associated with public disclosure of clinical trials are similar to the pharmaceutical industries, the iterative nature of device development introduces differences in what type of information needs to be disclosed during development and commercialization. The Second Dartmouth Device Development Symposium (3D2) held in October 2004 brought together thought leaders representing many of the stakeholders associated with medical device development. This consensus document arising from the proceedings of the 3D2 is offered to provide background to these issues and recommend pathways to implementation of device trial registration.

Clinical Trials as Topic↗
PubMed2006

A prospective registry to evaluate sirolimus-eluting stents implanted at coronary bifurcation lesions using the "crush technique".

The "crush technique" has been proposed as an alternative approach to treat bifurcation lesions because of its predictability and high procedural success rate. However, few data are available regarding its safety and long-term efficacy. We report the long-term clinical outcomes of patients with coronary bifurcation lesions treated with sirolimus-eluting stents using the crush technique. From April 2003 to May 2004, 120 patients with coronary bifurcation lesions were treated with sirolimus-eluting stents using the crush technique. Six months of clinical follow-up was completed in 95.8% of patients. Mean patient age was 64 years; 36% had diabetes mellitus, and the left anterior descending artery/diagonal was the most frequent bifurcation location (69%). Final kissing balloon inflation was performed in 87.5% of patients. Compared with the main vessel, side branch lesions were shorter, with a smaller reference diameter and final in-stent minimum lumen diameter. Procedural success was achieved in 97.5%. At 30 days of follow-up, 1 patient had died of noncardiac causes and 2 patients (1.7%) had subacute stent thrombosis. At 6 months of follow-up, target lesion revascularization was required in 13 patients (11.3%), all of whom had focal restenosis predominantly at the side branch ostium. In conclusion, the crush technique with final kissing balloon inflation can be safely used by experienced operators to treat highly complex bifurcation lesions with sirolimus-eluting stents. The safety profile of this technique is similar to that of other bifurcation stenting techniques reported thus far. Nonetheless, despite the excellent patency rates of the main vessel, the need for revascularization at the ostium of the side branch was not fully eliminated.

Angioplasty, Balloon, Coronary↗
PubMed2006

Paclitaxel-eluting stents vs vascular brachytherapy for in-stent restenosis within bare-metal stents: the TAXUS V ISR randomized trial.

CONTEXT: Restenosis within bare-metal stents is often treated with repeat percutaneous coronary intervention, although subsequent recurrence rates are high, with vascular brachytherapy (VBT) affording the best results. The effectiveness of drug-eluting stents in this setting has not been established. OBJECTIVE: To investigate the safety and efficacy of the polymer-based, slow-release paclitaxel-eluting stent in patients with restenotic lesions after prior stent implantation in native coronary arteries. DESIGN, SETTING, AND PATIENTS: Prospective, multicenter, randomized trial conducted between June 6, 2003, and July 16, 2004, at 37 North American academic and community-based institutions in 396 patients with in-stent restenosis of a previously implanted bare-metal coronary stent (vessel diameter, 2.5-3.75 mm; lesion length, < or =46 mm). INTERVENTIONS: Patients were randomly assigned to undergo angioplasty followed by VBT with a beta source (n = 201) or paclitaxel-eluting stent implantation (n = 195). Clinical and angiographic follow-up at 9 months was scheduled in all patients. MAIN OUTCOME MEASURE: Ischemia-driven target vessel revascularization at 9 months. RESULTS: Diabetes mellitus was present in 139 patients (35.1%). Median reference vessel diameter was 2.65 mm and median lesion length was 15.3 mm. In the VBT group, new stents were implanted in 22 patients (10.9%) and in the paclitaxel-eluting stent group, multiple stents were required in 57 patients (29.2%), with median stent length of 24 mm. Follow-up at 9 months was complete in 194 patients in the VBT group and 191 patients in the paclitaxel-eluting stent group (96.5% and 97.9%, respectively). For VBT and paclitaxel-eluting stents, respectively, the number of events and 9-month rates for ischemic target lesion revascularization were 27 (13.9%) vs 12 (6.3%) (relative risk [RR], 0.45; 95% confidence interval [CI], 0.24-0.86; P = .01); for ischemic target vessel revascularization, 34 (17.5%) vs 20 (10.5%) (RR, 0.60; 95% CI, 0.36-1.00; P = .046); and for overall major adverse cardiac events, 39 (20.1%) vs 22 (11.5%) (RR, 0.57; 95% CI, 0.35-0.93; P = .02), with similar rates of cardiac death or myocardial infarction (10 [5.2%] vs 7 [3.7%]; RR, 0.71; 95% CI, 0.28-1.83; P = .48) and target vessel thrombosis (5 [2.6%] vs 3 [1.6%]; RR, 0.61; 95% CI, 0.15-2.50; P = .72). Angiographic restenosis at 9 months was 31.2% (53 of 170 patients) with VBT and 14.5% (25 of 172 patients) with paclitaxel-eluting stents (RR, 0.47; 95% CI, 0.30-0.71; P<.001). CONCLUSION: Treatment of bare-metal in-stent restenotic lesions with paclitaxel-eluting stents rather than angioplasty followed by VBT reduces clinical and angiographic restenosis at 9 months and improves event-free survival. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00287573.

Aged↗
PubMed2006

Prognostic implications of creatine kinase elevation after primary percutaneous coronary intervention for acute myocardial infarction.

OBJECTIVES: We examined the prognostic implications of the absolute level and rate of increase of creatine kinase (CK) elevation after primary percutaneous coronary intervention (PCI). BACKGROUND: Peak creatine kinase (CK(peak)) and the rate of CK increase are related to reperfusion success and clinical outcomes after thrombolytic therapy for acute myocardial infarction (AMI). The utility of routine serial CK monitoring after primary PCI, in which normal antegrade blood flow is restored in most patients, is unknown. METHODS: In the Controlled Abciximab and Device Investigation to Lower Late Angioplasty Complications (CADILLAC) trial, 1,529 patients with AMI randomized to either stenting or balloon angioplasty, each with or without abciximab, had CK levels determined at baseline and at 8 +/- 1 h, 16 +/- 1 h, and 24 +/- 1 h after PCI. RESULTS: The CK(peak) occurred at baseline in 3.9% of patients, at 8 +/- 1 h in 69.6%, at 16 +/- 1 h in 20.0%, and at 24 +/- 1 h in 6.5%. The CK levels at all post-procedural time points were significantly higher in patients who died compared with the one-year survivors, as was CK(peak) (mean, 2,865 U/l vs. 1,885 U/l, respectively, p < or = 0.001). By multivariate analysis, CK(peak) was a significant predictor of one-year mortality (hazard ratio = 2.15, p = 0.0002), independent from post-PCI Thrombolysis In Myocardial Infarction (TIMI) flow. Both the improvement in left ventricular ejection fraction from baseline to seven months and its absolute level were inversely correlated with CK(peak) (p < 0.001 for both). In contrast, the time to CK(peak) was not an independent predictor of mortality or myocardial recovery. CONCLUSIONS: The CK(peak) after primary PCI is a powerful predictor of one-year mortality independent of other clinical and angiographic measures.

Angioplasty, Balloon, Coronary↗
PubMed2006

Prediction of one-year mortality among 30-day survivors after primary percutaneous coronary interventions.

Little information exists on the features that influence risk factors for death at 1 year among 30-day survivors of ST-elevation myocardial infarction (STEMI) that is treated with primary percutaneous coronary intervention (PCI). Accordingly, we examined 3,280 patients with STEMI who were enrolled in Stent-PAMI and CADILLAC trials, were treated with primary PCI, and survived >30 days after STEMI. Death at 1 year occurred in 74 patients (2.3%) who survived >30 days after their index STEMI. Patients who died at 1 year were more likely to be older and women and have lower body weight and greater prevalence of previous stroke. Similarly, the sum of ST elevations, 3-vessel or left anterior coronary disease, and final Thrombolysis In Myocardial Infarction grade <3 flow was higher, whereas left ventricular ejection fraction was lower among patients who died versus those who survived. The multivariate logistic regression model identified age >70 years (odds ratio [OR] 3.3 95% confidence interval [CI] 1.9 to 5.7), weight <80 kg (OR 1.9, 95% CI 1.1 to 3.6), any tachyarrhythmia during index hospitalization (defined as ventricular or supraventricular tachycardia that required treatment) (OR 2.4, 95% CI 1.2 to 4.8), number of diseased coronary arteries (OR 1.5, 95% CI 1.1 to 2.1), and left ventricular ejection fraction (each 10% decrease, OR 1.5, 95% CI 1.2 to 1.8) as factors independently associated with risk of death at 1 year among 30-day survivors. In conclusion, our study provides a method for clinicians to advise patients who are treated with primary PCI and survive the acute phase of STEMI with regard to patients' long-term prognosis, thus enhancing planning and setting up of realistic expectations.

Abciximab↗
PubMed2006

Platelet glycoprotein IIb/IIIa receptor inhibition as adjunctive treatment during saphenous vein graft stenting: differential effects after randomization to occlusion or filter-based embolic protection.

AIMS: Although embolic protection devices reduce complications during saphenous vein graft (SVG) stenting, adverse events still occur in approximately 10% of patients. IIb/IIIa antagonists have not been proven effective during SVG intervention. We hypothesized that adjunctive use of these agents might enhance the efficacy of embolic protection devices. METHODS AND RESULTS: In the prospective, multicentre FilterWire EX Randomized Evaluation trial, 651 patients undergoing SVG stenting were randomized to either filter-based FilterWire EX or balloon occlusion/aspiration GuardWire embolic protection devices. IIb/IIIa inhibitor use was at the discretion of the investigator, with randomization stratified by intended use. Patients pre-selected for IIb/IIIa inhibitor use (n = 345) had higher baseline risk, with increased 30-day major adverse cardiac events (MACE, 13.0 vs. 8.0%, P = 0.03). GuardWire assigned patients treated with IIb/IIIa inhibitors had higher 30-day MACE compared with those not treated with IIb/IIIa inhibitors (16.0 vs. 6.3%, P = 0.007). In contrast, MACE in high-risk FilterWire patients treated with IIb/IIIa inhibitors were similar to their lower risk, untreated counterparts (9.9 vs. 9.5%, P = 0.89). Multivariable analysis detected a borderline significant (P = 0.056) interaction for lower MACE between FilterWire and IIb/IIIa inhibitor use. Adjustment by the propensity to use IIb/IIIa inhibitors resulted in a significant (P = 0.023) interaction for lower MACE rates. IIb/IIIa inhibition in conjunction with FilterWire was associated with less abrupt closure, no reflow, or distal embolization. CONCLUSION: IIb/IIIa antagonists may improve procedural outcome during SVG stenting in high risk patients, utilizing filter-based embolic protection devices.

Aged↗
PubMed2006

Impact of body mass index on outcomes after primary angioplasty in acute myocardial infarction.

BACKGROUND: The prognostic importance of obesity after primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) is unknown. We therefore sought to investigate the impact of body mass index (BMI) in patients with AMI undergoing primary PCI. METHODS: In the CADILLAC trial, 2082 patients of any age with AMI within 12 hours onset undergoing primary PCI were randomized to balloon angioplasty versus stenting, each +/-abciximab. Outcomes were stratified by baseline BMI. RESULTS: Baseline BMI was measured in 2035 (98%) randomized patients; 552 (27%) patients have normal weight (BMI < 25 kg/m2), 915 (45%) were overweight (> or = 25 to < 30 kg/m2), and 568 (28%) were obese (> or = 30 kg/m2). Compared with normal-weight patients, obese patients were younger and more frequently had diabetes, hyperlipidemia, hypertension, non-anterior myocardial infarction, and higher creatinine clearance. Obese patients were less likely to develop thrombocytopenia (1.8% vs 4.2%), moderate hemorrhagic complications (1.4% vs 3.3%), or required blood product transfusions (3.2% vs 6.3%) (all P < or = .04). Obese compared with normal-weight patients had lower inhospital mortality (0.9% vs 2.7%, P = .03) at 30 days (1.1% vs 3.8%, P = .02) and 1 year (1.8% vs 7.5%, P < .0001). Independent predictors of 30-day and 1-year mortality included lower ejection fraction, advanced age, 3-vessel disease, anterior AMI, and lower creatinine clearance, but not BMI. CONCLUSIONS: Obese patients with AMI have an improved prognosis after primary PCI compared with normal-weight patients, a finding attributable to AMI onset at younger age, with better renal function and less anterior infarction.

Aged↗
PubMed2006

Impact of treatment delays on outcomes of primary percutaneous coronary intervention for acute myocardial infarction: analysis from the CADILLAC trial.

BACKGROUND: The impact of treatment delays on outcomes after primary percutaneous coronary intervention for acute myocardial infarction is controversial. METHODS: The CADILLAC trial randomized 2082 patients with acute myocardial infarction to stenting versus percutaneous transluminal coronary angioplasty, each with or without abciximab. RESULTS: Earlier reperfusion (<3 vs 3-6 vs >6 hours) was associated with lower 1-year mortality (2.6% vs 4.3% vs 4.8%, P = .046 for <3 vs > or = 3 hours), more frequent grade 2 to 3 myocardial blush (55% vs 53% vs 44%, P = .003), more frequent complete ST-segment resolution (64% vs 68% vs 47%, P = .006), and greater improvement in left ventricular function. Early reperfusion (<3 vs 3-6 vs > or = 3 hours) was associated with lower mortality in high-risk patients (3.8% vs 6.9% vs 7.0%, P = .051 for <3 vs > or = 3 hours) but not in low-risk patients (1.4% vs 0.6% vs 1.0%, P = .63). Door-to-balloon times were independently correlated with mortality in patients presenting early after the onset of symptoms (< or = 2 hours, hazard ratio 1.24, P = .013) but not late (>2 hours, heart rate 0.88, P = .33). CONCLUSIONS: Early reperfusion results in superior clinical outcomes, enhanced microvascular reperfusion, and better recovery of left ventricular function. Incremental treatment delays impact mortality more in high-risk versus low-risk patients and more in patients presenting early versus late after the onset of symptoms. These data emphasize the importance of minimizing treatment delays and have implications regarding patient triage for primary percutaneous coronary intervention.

Aged↗
PubMed2006

Relationship between infarct artery location, epicardial flow, and myocardial perfusion after primary percutaneous revascularization in acute myocardial infarction.

BACKGROUND: The association between infarct artery location, reperfusion success, and clinical outcomes after primary percutaneous coronary intervention (PCI) has not been characterized. We examined the infarct artery-specific impact of epicardial and myocardial flow and reperfusion after primary PCI for acute myocardial infarction. METHODS: Among 2082 patients undergoing primary PCI in the CADILLAC trial, myocardial blush grade, TIMI flow grade, ST-segment resolution, and clinical outcomes were analyzed according to the infarct artery. RESULTS: Baseline clinical characteristics did not significantly differ between patients experiencing infarction in the left anterior descending (LAD, 37%) versus left circumflex (18%) and right coronary artery (46%) distributions. Baseline left ventricular function was reduced, and collateral flow was less commonly present in patients with infarction involving the LAD. Achievement of final TIMI-3 flow, grade 3 myocardial blush, and ST-segment resolution >70% was also significantly less common in anterior infarction. Patients with anterior versus nonanterior infarction had significantly higher mortality at 30 days (3.4% vs 1.3%, P = .0006) and 1 year (6.5% vs 2.9%, P < .0001) and had increased 1-year rates of reinfarction (3.6% vs 1.7%, P = .009) and ischemic target vessel revascularization (16.1% vs 11.7%, P = .006). By multivariate analysis, LAD infarction was a powerful independent predictor of 1-year mortality (odds ratio 2.45, P = .009). CONCLUSIONS: Acute myocardial infarction involving the LAD distribution is associated with reduced left ventricular function, less frequent collateral flow, impaired myocardial perfusion and decreased reperfusion success, findings associated with reduced survival, and increased major adverse cardiac events compared with other vascular territories. These data provide mechanistic insights to the adverse prognosis of patients with anterior infarction.

Aged↗
PubMed2006

Six-month outcomes after percutaneous intervention for lesions in aortocoronary saphenous vein grafts using distal protection devices: results from the FIRE trial.

BACKGROUND: The filter-based FilterWire EX (Boston Scientific, Natick, MA) embolic protection system and the GuardWire (Medtronic, Santa Rosa, CA) balloon occlusion and aspiration device have been previously shown to reduce periprocedural complication rates of percutaneous coronary intervention for saphenous vein graft (SVG) disease and are considered the standard of care in this setting. The late clinical course after treatment with these devices has not been reported. METHODS: In the FIRE trial, 651 patients undergoing SVG intervention were randomized to either the FilterWire EX or GuardWire. Six-month rates of the primary end point (composite major adverse cardiac events [MACE]) and its components (death, myocardial infarction [MI], or target vessel revascularization) were studied. RESULTS: MACE at 30 days occurred in 9.9% of patients randomized to the FilterWire EX compared with 11.6% with the GuardWire, P = .53. By 6 months, MACE had increased to 19.3% and 21.9% in FilterWire EX and GuardWire groups, respectively, (relative risk 0.88, 95% CI 0.65-1.19; P = .44). All-cause 6-month mortality in the entire population was 3.5% (3.0% with FilterWire EX vs 4.1% with GuardWire, P = .53, with all deaths occurring after hospital discharge). MI occurred in 12.0% of patients at 6 months (12.1% vs 11.9% with the FilterWire EX and GuardWire, respectively, P = .99), and target vessel revascularization was required in 9.1% (8.2% vs 10.0%, respectively, P = .42). CONCLUSIONS: SVG intervention with the FilterWire EX and GuardWire distal protection devices resulted in similar outcomes at 6 months, although the clinical course after hospital discharge was not benign, with significant rates of death, MI, and repeat intervention.

Aged↗
PubMed2006

Intravascular ultrasound assessment of fibrous cap remnants after coronary plaque rupture.

BACKGROUND: Although intravascular ultrasound (IVUS) can detect plaque rupture, the fibrous cap remnant has not previously been studied in detail. The aim of the present study is to assess the fibrous cap remnants by IVUS in ruptured plaques. METHODS: In 53 patients, a ruptured plaque with a fibrous cap remnant was studied by IVUS. RESULTS: In 36 (68%) patients, the rupture of the fibrous cap appeared to have occurred at the shoulder. The absolute length of the fibrous cap remnant was significantly longer in the center rupture site compared with the shoulder rupture site (1.37 +/- 0.56 vs 0.84 +/- 0.34 mm, P = .001); however, the estimated length of the original fibrous cap did not differ between the 2 rupture site groups (2.28 +/- 0.66 vs 2.11 +/- 0.69, P = not significant). In none of the patients did the remnants of the fibrous cap cover the entire mouth of the cavity. The estimated absolute length of the missing part of the fibrous cap correlated significantly with the cavity area (r = 0.517, P < .001), the lesion external elastic membrane area (r = 0.330, P = .016), the lumen area (r = 0.289, P = .036), the maximum plaque thickness (r = 0.364, P = .007), and the length of the estimated original fibrous cap (r = 0.709, P < .001). CONCLUSION: In general, the postrupture fibrous cap does not cover the entire mouth of the ruptured plaque cavity in its postrupture state. Potential explanations include the following: (1) part of the fibrous cap may be too thin to be visualized with IVUS, (2) part of it may have embolized, or (3) the prerupture fibrous cap may have been stretched and/or there were postrupture changes in lesion geometry.

Aged↗
PubMed2006

Role of adenosine as adjunctive therapy in acute myocardial infarction.

Although early reperfusion and maintained patency is the mainstay therapy for ST elevation myocardial infarction, experimental studies demonstrate that reperfusion per se induces deleterious effects on viable ischemic cells. Thus "myocardial reperfusion injury" may compromise the full potential of reperfusion therapy and may account for unfavorable outcomes in high-risk patients. Although the mechanisms of reperfusion injury are complex and multifactorial, neutrophil-mediated microvascular injury resulting in a progressive decrease in blood flow ("no-reflow" phenomenon) likely plays an important role. Adenosine is an endogenous nucleoside found in large quantities in myocardial and endothelial cells. It activates four well-characterized receptors producing various physiological effects that attenuate many of the proposed mechanisms of reperfusion injury. The cardio-protective effects of adenosine are supported by its role as a mediator of pre- and post-conditioning. In experimental models, administration of adenosine in the peri-reperfusion period results in a marked reduction in infarct size and improvement in ventricular function. The cardioprotective effects in the canine model have a narrow time window with the drug losing its effect following three hours of ischemia. Several small clinical studies have demonstrated that administration of adenosine with reperfusion therapy reduces infarct size and improves ventricular function. In the larger AMISTAD and AMISTAD II trials a 3-h infusion of adenosine as an adjunct to reperfusion resulted in a striking reduction in infarct size (55-65%). Post hoc analysis of AMISTAD II showed that this was associated with significantly improved early and late mortality in patients treated within 3.17 h of symptoms. An intravenous infusion of adenosine for 3 h should be considered as adjunctive therapy in high risk-patients undergoing reperfusion therapy.

Adenosine↗