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Biomedical subjects

Neil J Weissman

Publications and source records attributed to Neil J Weissman.

At least 55 records · Page 3Linked to original sources
PubMed2004

Subclinical thyroid disease: scientific review and guidelines for diagnosis and management.

CONTEXT: Patients with serum thyroid-stimulating hormone (TSH) levels outside the reference range and levels of free thyroxine (FT4) and triiodothyronine (T3) within the reference range are common in clinical practice. The necessity for further evaluation, possible treatment, and the urgency of treatment have not been clearly established. OBJECTIVES: To define subclinical thyroid disease, review its epidemiology, recommend an appropriate evaluation, explore the risks and benefits of treatment and consequences of nontreatment, and determine whether population-based screening is warranted. DATA SOURCES: MEDLINE, EMBASE, Biosis, the Agency for Healthcare Research and Quality, National Guideline Clearing House, the Cochrane Database of Systematic Reviews and Controlled Trials Register, and several National Health Services (UK) databases were searched for articles on subclinical thyroid disease published between 1995 and 2002. Articles published before 1995 were recommended by expert consultants. STUDY SELECTION AND DATA EXTRACTION: A total of 195 English-language or translated papers were reviewed. Editorials, individual case studies, studies enrolling fewer than 10 patients, and nonsystematic reviews were excluded. Information related to authorship, year of publication, number of subjects, study design, and results were extracted and formed the basis for an evidence report, consisting of tables and summaries of each subject area. DATA SYNTHESIS: The strength of the evidence that untreated subclinical thyroid disease is associated with clinical symptoms and adverse clinical outcomes was assessed and recommendations for clinical practice developed. Data relating the progression of subclinical to overt hypothyroidism were rated as good, but data relating treatment to prevention of progression were inadequate to determine a treatment benefit. Data relating a serum TSH level higher than 10 mIU/L to elevations in serum cholesterol were rated as fair but data relating to benefits of treatment were rated as insufficient. All other associations of symptoms and benefit of treatment were rated as insufficient or absent. Data relating a serum TSH concentration lower than 0.1 mIU/L to the presence of atrial fibrillation and progression to overt hyperthyroidism were rated as good, but no data supported treatment to prevent these outcomes. Data relating restoration of the TSH level to within the reference range with improvements in bone mineral density were rated as fair. Data addressing all other associations of subclinical hyperthyroid disease and adverse clinical outcomes or treatment benefits were rated as insufficient or absent. Subclinical hypothyroid disease in pregnancy is a special case and aggressive case finding and treatment in pregnant women can be justified. CONCLUSIONS: Data supporting associations of subclinical thyroid disease with symptoms or adverse clinical outcomes or benefits of treatment are few. The consequences of subclinical thyroid disease (serum TSH 0.1-0.45 mIU/L or 4.5-10.0 mIU/L) are minimal and we recommend against routine treatment of patients with TSH levels in these ranges. There is insufficient evidence to support population-based screening. Aggressive case finding is appropriate in pregnant women, women older than 60 years, and others at high risk for thyroid dysfunction.

Humans↗
PubMed2004

The importance of gender on coronary artery size: in-vivo assessment by intravascular ultrasound.

BACKGROUND: It remains controversial whether women have smaller coronary arteries than men because of a gender-specific trait, or whether the observed differences are primarily due to a difference in body size. Intravascular ultrasound (IVUS), with its ability to provide unique coronary images that allow precise measurement of arterial size in vivo, is ideally suited to address this issue. HYPOTHESIS: Female gender, independent of body size, is associated with smaller coronary artery size as measured by intracoronary ultrasound. METHODS: Intravascular ultrasound images of normal left main arteries were identified retrospectively from a single center database. Associations between demographic and clinical characteristics (including body size) and left main coronary dimensions were assessed with univariant and multivariate regression analyses. RESULTS: We identified 257 completely normal left main arteries. Mean left main arterial areas were smaller in women than in men (17.2 vs. 20.6 mm2, p < 0.001), as were mean luminal areas (14.0 vs. 16.7 mm2, p < 0.001). By multiple regression analysis, the independent predictors of left main lumen were body surface area (p < 0.001) and gender (p = 0. 003). CONCLUSIONS: Body surface area and gender are both independent predictors of coronary artery size, although body size has a greater influence than gender.

Aged↗
PubMed2004

Intravascular ultrasound predictors of subacute vessel closure after balloon angioplasty or atherectomy.

BACKGROUND: Factors leading to subacute vessel closure after percutaneous coronary intervention (PCI) have not been well established in lesions treated with balloon angioplasty or atherectomy. METHODS AND RESULTS: We used intravascular ultrasound (IVUS) to determine the pre- and post-PCI characteristics involved in subacute vessel closure after PCI. Of 3,403 patients undergoing IVUS imaging during coronary balloon angioplasty or atherectomy, 8 patients (0.2%) developed angiographically documented subacute vessel closure within 1 week post-PCI and were compared to a group matched by procedure date (within 6 months), age, gender, stable or unstable angina, lesion location and treatment (balloon angioplasty or atherectomy). IVUS identified at least one cause for subacute vessel closure in 87% of patients (vs 25% in matched lesions, p < 0.01). Causes were all procedure-related and included inadequate final lumen (60%), dissection (50%) and thrombus (25%). Pre-procedure lesion characteristics were not different from matched lesions. CONCLUSIONS: Subacute vessel closure after balloon angioplasty or atherectomy is mostly related to insufficient post-procedure lumen dimension or dissection.

Aged↗
PubMed2004

Safety of percutaneous coronary intervention alone in symptomatic patients with moderate and severe valvular aortic stenosis and coexisting coronary artery disease: analysis of results in 56 patients.

Whether percutaneous coronary intervention (PCI) alone is safe in patients with moderate or severe aortic stenosis (AS) and coexisting coronary artery disease (CAD), and whether aortic valve replacement (AVR) can be deferred in patients with moderate AS by undergoing PCI alone is not known. We conducted a retrospective study of surgically inoperable patients with AS who underwent PCI (moderate AS, n = 28; and severe AS, n = 28) and compared to those with AVR (n = 55). The clinical characteristics, procedural complications, in-hospital and long-term clinical outcomes of PCI were compared. Baseline and procedural characteristics were similar except that lower age, hypertension, and renal impairment were seen in the AVR group. In-hospital complications were comparable among the 3 groups. Six-month and 1-year rates of myocardial infarction (MI), non-Q-wave MI, death and out-of-hospital death were similar between AVR and moderate AS patients (p = NS) and significantly high (p < 0.04) in patients with severe AS. On multivariate analysis, severe AS was the only significant predictor of 6-month and 1-year mortality. Our study suggests that PCI is safe in patients with moderate AS and coexisting CAD but is associated with poor outcomes in patients with severe AS.

Aged↗
PubMed2003

Incidence, predictors, and prognostic implications of bleeding and blood transfusion following percutaneous coronary interventions.

Bleeding related to percutaneous coronary intervention (PCI) occurs relatively frequently. We retrospectively investigated the incidence, predictors, and prognostic impact of periprocedural bleeding and transfusion in 10,974 patients who underwent PCI. Bleeding definitions were based on Thrombolysis In Myocardial Infarction (TIMI) criteria: (1) major bleeding (n = 588; 5.4%): if patients had a hemorrhagic stroke or if hematocrit decreased >15 points or by 10 to 15 points with clinical bleeding; (2) minor bleeding (n = 1,394; 12.7%): if hematocrit decreased <10 points with clinical bleeding or by 10 to 15 points without clinical bleeding; and (3) no bleeding (n = 8,992; 81.9%): if hematocrit decreased <10 points without clinical bleeding. Patients with major bleeding were older than patients with minor or no bleeding (67.8 +/- 11 vs 65.9 +/- 11 vs 63.6 +/- 11 years, respectively; p <0.001) and more often experienced intraprocedural complications, such as emergency use of an intra-aortic balloon pump (13.6% vs 6.5% vs 2.3%, respectively; p <0.001). Multivariate logistic regression analysis identified the use of an intra-aortic balloon pump (odds ratio [OR] 3.0, p <0.0001), procedural hypotension (OR 2.9, p <0.001), and age >80 years (OR 1.9 compared with age <50 years, p = 0.001) as the strongest predictors for major bleeding. Patients who had major bleeding had higher in-hospital and 1-year mortality compared with patients with minor or no bleeding. Bleeding was an independent predictor of in-hospital death. Thus, periprocedural major bleeding occurs relatively frequently and is associated with adverse outcomes. Patients >80 years of age who experience intraprocedural complications are at particularly high risk.

Age Factors↗
PubMed2003

Incidence and mechanism of late stent malapposition after phosphorus-32 radioactive stent implantation.

Late stent malapposition is a potential complication of intracoronary brachytherapy. The aim of our study was to determine the incidence and mechanism of late stent malapposition after implantation of phosphorus-32 radioactive stents. We analyzed 159 patients for de novo lesions after the implantation of phosphorus-32 radioactive stents. There were 15 late stent malappositions. The incidence of malapposition was higher in patients who received Hot-Ends Isostents. External elastic membrane expansion greater than plaque increase in malapposed segments was observed. Late stent malapposition is caused by a localized increase in external elastic membrane that is greater than the increase in plaque area; this is believed to be a dose-dependent phenomenon because it was more common with Hot-Ends Isostents.

Brachytherapy↗
PubMed2003

Volumetric intravascular ultrasound evidence that distal embolization during acute infarct intervention contributes to inadequate myocardial perfusion grade.

We studied 35 consecutive patients with myocardial infarction (MI) who were treated with direct infarct percutaneous coronary intervention (PCI) using standard angiographic (complete assessment of flow grade and blush grade) and pre- and post-PCI volumetric intravascular ultrasound analysis. Plaque reduction, which is evidence of distal embolization, contributes to inadequate tissue reperfusion in this lesion setting and supports the use of distal protection in the setting of an acute MI.

Aged↗
PubMed2003

Impact of preinterventional arterial remodeling on neointimal hyperplasia after implantation of (non-polymer-encapsulated) paclitaxel-coated stents: a serial volumetric intravascular ultrasound analysis from the ASian Paclitaxel-Eluting Stent Clinical Trial (ASPECT).

BACKGROUND: This study used serial volumetric intravascular ultrasound (IVUS) to evaluate the effect of preinterventional arterial remodeling on in-stent intimal hyperplasia (IH) after implantation of non-polymer-encapsulated paclitaxel-coated stents. METHODS AND RESULTS: Patients were randomized to placebo or one of two doses of paclitaxel (low dose, 1.28 microg/mm2; high dose, 3.10 microg/mm2). Complete preinterventional, post-stent implantation, and follow-up IVUS were available in 18 low-dose and 21 high-dose patients. IH volumes were similar in low-dose and high-dose patients: 17.6+/-15.1 mm3 in low-dose patients and 13.1+/-13.3 mm3 in high-dose patients (P=0.3). Therefore, IVUS findings in low- and high-dose patients were combined. Preinterventional remodeling was assessed by comparing lesion site to proximal and distal reference arterial area: positive remodeling (lesion>proximal reference, n=13), intermediate remodeling (distal reference<lesion<proximal reference, n=13), and negative remodeling (lesion<distal reference, n=13). During follow-up, there was a decrease in lumen volume in positive remodeling lesions (from 106+/-30 to 90+/-27 mm3; P=0.0067) and in intermediate remodeling lesions (from 97+/-28 to 76+/-31 mm3; P=0.0004), but not in negative remodeling lesions (99+/-27 versus 92+/-32 mm3; P=0.15). The follow-up IH volume was lower in negative remodeling lesions (5+/-7 mm3) compared with positive remodeling (20+/-14 mm3; P=0.0051) and intermediate remodeling lesions (20+/-15 mm3; P=0.0043); however, IH volume was virtually identical in positive and intermediate remodeling lesions. Multivariate linear regression analysis determined that remodeling and inflation pressure were independent predictors of IH volume; variables tested in the model included diabetes, acute coronary syndromes, dose, remodeling, and preinterventional plaque burden. CONCLUSIONS: Preinterventional arterial remodeling, especially negative remodeling, influences neointimal hyperplasia suppression after implantation of non-polymer-encapsulated paclitaxel-coated stents.

Coronary Restenosis↗
PubMed2003

Predictors of subacute stent thrombosis: results of a systematic intravascular ultrasound study.

BACKGROUND: Factors leading to subacute stent thrombosis after percutaneous coronary intervention (PCI) have not been well established. We assessed the pre- and post-PCI intravascular ultrasound (IVUS) characteristics of subacute stent thrombosis. METHODS AND RESULTS: We analyzed 7484 consecutive patients without acute myocardial infarction who were treated with PCI and stenting and underwent IVUS imaging during the intervention. Twenty-seven (0.4%) had angiographically documented subacute closure <1 week after PCI (median time to subacute closure, 24 hours). Subacute closure lesions were compared with a control group (selected to be 3 times the abrupt closer group) matched by procedure date (within 6 months), age, gender, stable or unstable angina, lesion location, and additional treatment (balloon angioplasty or atherectomy). Postintervention IVUS did not identify a cause in 22% and did identify at least 1 cause for abrupt closure in 78% of patients (versus 33% in matched lesions, P=0.0002). In 48% of the patients, there were multiple causes in 48% (versus 3% in matched lesions, P<0.0001). Causes included dissection (17%), thrombus (4%), and tissue protrusion within the stent struts leading to lumen compromise lumen (4%). A total of 83% of patients with >1 of these abnormal morphologies also had reduced lumen dimensions post-PCI (final lumen <80% reference lumen). Preprocedural lesion characteristics were not different from matched lesions. CONCLUSIONS: Subacute stent thrombosis is infrequently related to the preintervention lesion characteristics. Inadequate postprocedure lumen dimensions, alone or in combination with other procedurally related abnormal lesion morphologies (dissection, thrombus, or tissue prolapse), contribute to this phenomenon.

Angioplasty, Balloon, Coronary↗
PubMed2003

Intravascular ultrasound analysis of infarct-related and non-infarct-related arteries in patients who presented with an acute myocardial infarction.

BACKGROUND: Previous studies have reported diffuse destabilization of atherosclerotic plaques in acute myocardial infarction (AMI). METHODS AND RESULTS: We used intravascular ultrasound (IVUS) to assess 78 coronary arteries (38 infarct-related arteries [IRAs] with culprit and nonculprit lesions and 40 non-IRAs) from 38 consecutive AMI patients. IVUS analysis included qualitative and quantitative measurements of reference and lesion external elastic membrane (EEM), lumen, and plaque plus media (P&M) area. Positive remodeling was defined as lesion/mean reference EEM >1.0. Culprit lesions were identified by a combination of ECG, wall motion abnormalities (ventriculogram or echocardiogram), scintigraphic perfusion defects, and coronary angiogram. Culprit lesions contained more thrombus (23.7% versus 3.4% in nonculprit IRA plaques and 3.1% in non-IRA plaques; P=0.0011). Culprit lesions were predominantly hypoechoic (63.2% versus 37.9% of nonculprit IRA plaques and 28.1% of non-IRA plaques; P=0.0022). Culprit lesions were longer (17.5+/-10.1, 9.8+/-4.0, and 10.3+/-5.7 mm, respectively; P<0.0001), had larger EEM area (15.0+/-6.0, 11.5+/-5.7, and 12.6+/-5.6 mm2, respectively; P=0.0353) and P&M area (13.0+/-6.0, 7.5+/-3.7, 9.3+/-4.3 mm2, respectively; P<0.0001), smaller lumens (2.0+/-0.9, 4.1+/-3.1, and 3.4+/-2.5 mm2, respectively; P=0.0009), and more positive remodeling (79.4%, 59.0%, and 50.8%, respectively; P=0.0155). The frequency of plaque rupture/dissection was greater in culprit, nonculprit IRA, and non-IRA plaques in AMI patients than in a control group of chronic stable angina patients with multivessel IVUS imaging. CONCLUSIONS: Culprit plaques have more markers of instability (thrombus, positive remodeling, and large plaque mass); however, these markers of instability are not typically found elsewhere. This suggests that the vascular event in AMI patients is determined by local pre-event lesion morphologies.

Angina Pectoris↗
PubMed2003

Regional remodeling as the cause of late stent malapposition.

BACKGROUND: Late stent malapposition (LSM) is only detected if intravascular ultrasound (IVUS) is performed at implantation and follow-up. We used a novel "regional" IVUS analysis to assess the mechanism of LSM. METHODS AND RESULTS: Corresponding image slices on postimplantation and follow-up IVUS studies of 11 malapposed stents were identified and electronically rotated until they were aligned. The geometric center of the stent was identified, and the angle of late malapposition measured. Radii were drawn from this center through the transition points between complete apposition and LSM. These two circumferences were divided into equal arcs, and radii were drawn to the external elastic membrane (EEM). Measurements included EEM radius and circumference, plaque and media (P&M=EEM minus stent radius) thickness and area, and stent-intima separation. Mean baseline EEM radius and P&M thickness were similar in apposed and malapposed circumferences. At follow-up, mean EEM radius increase within the malapposed circumference (0.57+/-0.34 mm) was larger than within the apposed circumference (0.16+/-0.18 mm; P=0.0004). DeltaEEM for each malapposed radius was greater than for each apposed radius (P<0.05 for all comparisons). Stent-intima separation correlated with EEM radius increase within the malapposed circumference (r=0.83, P=0.0013). At follow-up, the mean P&M thickness decreased in the malapposed circumference (-0.31+/-0.22 mm; P<0.0001). However, the decrease in P&M thickness in the malapposed circumference occurred because the same P&M area was distributed over a larger circumference (4.1+/-1.6 mm to 5.4+/-3.0 mm; P=0.05), the result of positive remodeling. CONCLUSIONS: The main cause of LSM is a regional increase in EEM (regional positive remodeling).

Blood Vessel Prosthesis↗
PubMed2003

Catheter-based autologous bone marrow myocardial injection in no-option patients with advanced coronary artery disease: a feasibility study.

OBJECTIVES: We conducted a pilot study to evaluate the feasibility of transendocardial delivery of autologous bone marrow (ABM) strategy in patients with severe symptomatic chronic myocardial ischemia not amenable to conventional revascularization. BACKGROUND: Transendocardial injection of ABM cells appears to enhance perfusion of ischemic porcine myocardium. METHODS: Ten patients underwent transendocardial injection of freshly aspirated and filtered unfractionated ABM using left ventricular electromechanical guidance. Twelve injections of 0.2 ml each were successfully delivered into ischemic noninfarcted myocardium pre-identified by single-photon emission computed tomography perfusion imaging. RESULTS: Autologous bone marrow injection was successful in all patients and was associated with no serious adverse effects; in particular, there was no arrhythmia, evidence of infection, myocardial inflammation, or increased scar formation. Two patients were readmitted for recurrent chest pain. At three months, Canadian Cardiovascular Society angina score significantly improved (3.1 +/- 0.3 vs. 2.0 +/- 0.94, p = 0.001), as well as stress-induced ischemia occurring within the injected territories (2.1 +/- 0.8 vs. 1.6 +/- 0.8, p < 0.001). Treadmill exercise duration, available in nine patients, increased, but the change was not significant (391 +/- 155 vs. 485 +/- 198, p = 0.11). CONCLUSIONS: This study provides preliminary clinical data indicating feasibility of catheter-based transendocardial delivery of ABM to ischemic myocardium.

Bone Marrow Transplantation↗