Change In Minimum Diameter Research Articles

Changes in renal artery dimensions are associated with clinical response to radiofrequency renal denervation: a series of studies using quantitative angiography and intravascular ultrasound.

Renal denervation (RDN) can cause focal (notches) and global (spasms) changes in renal artery dimensions. We quantified these changes and related them to renal norepinephrin tissue content in animals and to blood pressure (BP) changes in patients. We measured renal artery dimensions pre-RDN and post-RDN, utilizing quantitative renal angiography (QRA) in a porcine model and in a retrospective patient cohort, and intravascular ultrasound (IVUS) in a prospective patient cohort. Focal and global measurements were minimum and mean diameter/area/volume with QRA, minimum lumen/vessel/wall area and volume with IVUS. BP was assessed with 24-h ambulatory monitoring, norepinephrin content with liquid chromatography. In 36 pigs treated unilaterally with RDN, norepinephrin content of the treated right kidney was 48.2% of the untreated left kidney. QRA measurements following RDN were associated with norepinephrin content only of the (treated) right kidney. In the human QRA study (n = 43 patients), mean 24-h BP fell by 8/4 and 12/6 mmHg at 1 and 12 months, respectively. More pronounced changes in QRA measurements were associated with a more pronounced BP drop. In multiple regression models, the change in minimum diameter was independently associated with BP changes at 12 months. In the prospective IVUS study (n = 17 patients), a larger decrease in minimum lumen/vessel area and larger increase of wall area/volume were associated with a larger BP drop. Focal and global changes in renal arteries following RDN can be quantified, using QRA or IVUS, and may serve as markers of a successful procedure.

The Estrogen Replacement and Atherosclerosis (ERA) Study: Study Design and Baseline Characteristics of the Cohort

The Estrogen Replacement and Atherosclerosis (ERA) trial is a three-arm, randomized, placebo-controlled, double-blind trial to evaluate the effects of estrogen replacement therapy (0.625 mg/day oral conjugated estrogen) with or without continuous low-dose progestin (2.5 mg oral medroxyprogesterone acetate/day) versus placebo on progression of atherosclerosis. A total of 309 postmenopausal women at five sites underwent baseline coronary angiography and were randomized. Participants will have repeat coronary angiography after an average of 3.25 years of treatment. The primary outcome of interest will be change in minimum diameter of the major epicardial segments, as assessed by quantitative coronary angiography. The primary aim is to test the hypothesis that either form of hormone therapy will slow the progression or induce regression of coronary atherosclerosis compared to placebo. The secondary aims are to assess the effects of the two treatments versus placebo on endothelial function (measured using flow-mediated vasodilator responses), on several presumed mediators of estrogen's effect on atherosclerosis (i.e., plasma lipids and lipoproteins, blood pressure, glucose metabolism, hemostatic factors, and antioxidant activity), on other factors that influence the development of coronary heart disease (i.e., diet, smoking status, exercise, weight, and health-related quality of life issues), and on clinical cardiovascular events. The ERA trial is the first angiographic endpoint clinical trial to examine the effects of postmenopausal hormone replacement on coronary atherosclerosis in women. It will provide an unparalleled opportunity to determine if either regimen of hormone therapy is effective in slowing the progress of angiographically defined coronary atherosclerosis. This study will complement other estrogen replacement trials, such as the PEPI, HERS, and Women's Health Initiative studies, to provide a more comprehensive examination of the effects of estrogen replacement on cardiovascular risk factors, anatomic and functional manifestations of atherosclerosis, and risk for coronary heart disease in postmenopausal women. Control Clin Trials 2000;21:257–285

769-3 Lipid Intervention and Progression of Coronary Atherosclerosis

The Coronary Intervention Study, CIS, is a multicentre, randomized, doubleblind. placebo-controlled study to investigate the effects of lipid-modifying therapy on progression in 254 men with documented coronary artery disease (CAD) and hypercholesterolemia. Entry criteria were the presence of at least 3 coronary stenoses of ≥25% and a mean serum total cholesterol (C) of : ≥207 mg/dl after diet. Treatment with up to 40 mg simvastatin (S) or placebo (P) o.d. included diet and — as a reserve medication: — colestyramine, and was pursued for 2.3 years (S/P: 865/835 days). The two treatment groups (see below) were comparable with respect to baseline variables, e.g. average age (49.9/49.1 y), height(175.4/175.2 cm), weight(80.1/80 kg), blood pressure (123,5/79.8 vs. 123.1/78.6 mmHg), diastolic hypertension ≥90 mmHg (9.6/9.1%), fasting serum glucose ≥120 mg/dl (2.9/5.1%), family history (47.1/48.0%), smoking (83.6/85.9), ventricular score (1.0/0.9), coronary score (2.12/1.93 — vessel-disease), and lipid values, with a baseline LDL-C of 163.8/166.7 mg/dl. Treatment resulted in significant changes of serum lipids with a decrease of LDL-C by 33% and -1.5% in the Sand P group, respectively. 204 (81; 104/100) patients had a second angiography. Two primary end points were chosen: — the within-patient change in minimum diameter avenged over all assessable coronary segments (“ΔminD”, determined by quantitative analysis using the CAAS system), and—the visual Global Change Score (“GCS”, Blankenhorn), and calculated according to Bonferroni-Holme on a multiple significance level of 5%. The detailed results will be presented. Supported by MSD Sharp and Dohme, Munich, Germany.

Quantitative angiographic and statistical methods to assess serial changes in coronary luminal diameter and implications for atherosclerosis regression trials

The purpose of this study was (1) to determine a threshold for categorizing individual coronary lesions as either significantly progressing or regressing, (2) to determine whether multiple lesions within individual patients progress at independent rates, and (3) to calculate sample sizes for atherosclerosis regression trials. Seventeen patients with 46 significant lesions (2.7 lesions/patient) underwent repeat coronary arteriography 3.0 years apart. With use of the standard error of the mean change in diameter from initial to repeat catheterization across 5 pairs of consecutive end-diastolic frames, individual lesions were categorized as either significantly (p < 0.01) progressing or regressing if there was a 0.27 mm change in minimum diameter or a 7.8 percent point change in percent stenosis. The mean diameter change of a sample of lesions can also be analyzed as a continuous variable using either the lesions or the patient as the primary unit of analysis. A lesion-specific analysis can be accomplished using a multiple regression model that accounts for the intraclass correlation (ϱ) in the degree of change among multiple lesions within individual patients. The intraclass correlations in percent stenosis (ϱ = 0.01) and minimum diameter (ϱ = −0.24) were low, indicating that disease progression in different lesions within individual patients is nearly independent. With use of this model, 50 patients per treatment group would permit the detection of a 5.5% difference between treatment group means in the change in minimum diameter and a 2.7% percentage point (not percent) difference in the change in percent stenosis. Thus, quantitative angiography using multiframe averaging permits the detection of relatively small changes in the diameter of individual lesions, and the use of a small number of patients to detect differences in the rate of atherosclerosis progression among treatment groups.