Use of chelation therapy after coronary angiography.

PURPOSE: Among patients who had undergone coronary angiography, we sought to determine the proportion of chelation therapy users, their sociodemographic and clinical characteristics, and the association of chelation therapy with subsequent revascularization. METHODS: We studied all patients who underwent coronary angiography in the province of Alberta, Canada, during 1995 and 1996. The cohort was followed for up to 6 years to determine subsequent revascularization status. Use of chelation therapy was determined by a mailed survey 1 year after angiography. RESULTS: Among the 5854 patients who responded to the mail survey (70% response rate), 210 (3.6%) reported current use of chelation therapy and 252 (4.3%) reported past use. Current use of chelation therapy was associated with extensive coronary artery disease (adjusted odds ratio [OR] = 3.3; 95% confidence interval [CI]: 1.9 to 5.7 for 3-vessel disease; and OR = 2.7; 95% CI: 1.2 to 6.0 for left main disease, as compared with those with normal anatomy) and the absence of diabetes (OR = 0.6; 95% CI: 0.4 to 0.9). Current users were less likely to have undergone percutaneous transluminal coronary angioplasty (OR = 0.7; 95% CI: 0.5 to 0.9) and coronary artery bypass graft (CABG) surgery (OR = 0.3; 95% CI: 0.2 to 0.5) in the first year after angiography, but were as likely as nonusers of chelation therapy to have undergone CABG surgery in the subsequent 3- to 5-year period (adjusted hazard ratio [HR] = 1.1; 95% CI: 0.7 to 1.9). Past use of chelation therapy was associated with a history of CABG surgery before coronary angiography (OR = 1.6; 95% CI: 1.1 to 2.3) and extensive coronary artery disease. Past users were also more likely to have undergone CABG surgery in the follow-up period (HR = 1.7; 95% CI: 1.1 to 2.6). CONCLUSIONS: About 8% of patients who underwent cardiac catheterization for coronary artery disease were using or had previously tried chelation therapy. Users may have foregone revascularization in favor of this less invasive yet unproven treatment, with some users subsequently undergoing conventional treatment after chelation. Alternatively, some patients may have turned to chelation as a "last resort" after having been judged unsuitable for revascularization.

Comparison of 2 methods for calculating adjusted survival curves from proportional hazards models.

CONTEXT: Adjusted survival curves are often presented in medical research articles. The most commonly used method for calculating such curves is the mean of covariates method, in which average values of covariates are entered into a proportional hazards regression equation. Use of this method is widespread despite published concerns regarding the validity of resulting curves. OBJECTIVE: To compare the mean of covariates method to the less widely used corrected group prognosis method in an analysis evaluating survival in patients with and without diabetes. In the latter method, a survival curve is calculated for each level of covariates, after which an average survival curve is calculated as a weighted average of the survival curves for each level of covariates. DESIGN, SETTING, AND PATIENTS: Analysis of cohort study data from 11 468 Alberta residents undergoing cardiac catheterization between January 1, 1995, and December 31, 1996. MAIN OUTCOME MEASURES: Crude and risk-adjusted survival for up to 3 years after cardiac catheterization in patients with vs without diabetes, analyzed by the mean of covariates method vs the corrected group prognosis method. RESULTS: According to the mean of covariates method, adjusted survival at 1044 days was 94.1% and 94.9% for patients with and without diabetes, respectively, with misleading adjusted survival curves that fell above the unadjusted curves. With the corrected group prognosis method, the corresponding survival values were 91.3% and 92.4%, with curves that fell more appropriately between the unadjusted curves. CONCLUSIONS: Misleading adjusted survival curves resulted from using the mean of covariates method of analysis for our data. We recommend using the corrected group prognosis method for calculating risk-adjusted curves.

Validation of three myocardial jeopardy scores in a population-based cardiac catheterization cohort.

BACKGROUND: The Jeopardy Score from Duke University and the Myocardial Jeopardy Index from the Bypass Angioplasty Revascularization Investigation (BARI) have been validated but never applied to a large unselected cohort. We assessed the prognostic value of these existing jeopardy scores, along with that of a new Lesion Score developed for the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH), a clinical data collection initiative capturing all patients undergoing cardiac catheterization in the province of Alberta. METHODS: The predictive value of these three scores were compared in a cohort of >20,000 patients (9922 treated medically, 6334 treated with percutaneous intervention, and 3811 treated with bypass surgery). Scores were considered individually in logistic regression models for their ability to predict outcome and then added to models containing sociodemographic data, comorbidities, ejection fraction, indication for procedure, and descriptors of coronary anatomy. RESULTS: All scores were found to be predictive of 1-year mortality, especially when patients are treated medically or with percutaneous intervention. In these patients, the APPROACH Lesion Score performed slightly better than the other jeopardy scores. The Duke Jeopardy Score was most predictive in those patients undergoing coronary bypass surgery. CONCLUSIONS: Myocardial jeopardy scores provide independent prognostic information for patients with ischemic heart disease, especially if those patients are treated medically or with percutaneous intervention. These scores represent potentially valuable tools in cardiovascular outcome studies. The APPROACH Lesion Score may perform slightly better than previously developed jeopardy scores.

Long-term survival in 11,661 patients with multivessel coronary artery disease in the era of stenting: a report from the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) Investigators.

BACKGROUND: Studies of survival of patients with multivessel coronary artery disease (MVD) in the prestent era suggested that outcomes after coronary artery bypass surgery (CABG) are similar to those after percutaneous coronary intervention (PCI) in subsets of coronary severity. The purpose of this study of the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) was to examine the association between treatment and survival up to 5 years in patients with MVD enrolled from 1995 through 1998. METHODS AND RESULTS: Data on patient characteristics were obtained at the time of the initial coronary angiography. Survival was determined through data linkage to the provincial Bureau of Vital Statistics. Risk-adjusted hazard ratios were calculated to compare different treatments. In the 11,661 patients with MVD, CABG was the initial therapy in 3782, PCI in 3540, and medical therapy in 4339. Cumulative 5-year survival was 91.4% with CABG, 91.9% with PCI, and 82.9% with medical therapy (P <.001). Hazard ratios were CABG: medical 0.53 (95% confidence interval [CI] 0.46-0.71), PCI: medical 0.65 (95% CI 0.56-0.74), and CABG: PCI 0.81 (95% CI 0.68-0.96). Analysis across coronary severity groups revealed a benefit of CABG compared with PCI only in the group with severe left main CAD: 0.30 (95% CI 0.17-0.54). CONCLUSIONS: In a multicenter clinical setting, MVD patients treated with revascularization have significantly higher 5-year survival rate than do those treated medically. Risk-adjusted comparison reveals PCI treatment to be associated with long-term survival similar to treatment with CABG in all coronary severity subgroups except the group with severe left main coronary artery disease. Patient selection factors are likely to be contributing to these findings.

Poor long-term survival after coronary angiography in patients with renal insufficiency.

Cardiovascular disease is common among dialysis patients, but much less is known regarding non-dialysis-dependent renal insufficiency (NDDRI) and its association with cardiac disease. We undertook a study to assess the impact of renal insufficiency on survival post-coronary angiography by comparing three groups of patients: dialysis-dependent patients, patients with NDDRI (creatinine > 2.3 mg/dL), and a reference group with creatinine levels less than 2.3 mg/dL and not on dialysis therapy. We used a prospective cohort that consisted of all patients undergoing coronary angiography in Alberta, Canada, from January 1, 1995, to December 31, 1997. Of the 16,989 patients, 196 patients (1.2%) were on dialysis therapy, 262 patients (1.5%) had NDDRI, and 16,531 patients (97.3%) formed the reference group. Mortality rates 1 year after angiography were 30.2% for patients with NDDRI, 15.8% for dialysis patients, and 4.1% for the reference group. Compared with the reference group, crude 4-year survival was significantly worse for dialysis patients and those with NDDRI, with hazard ratios of 4.05 (95% confidence interval, 3.02 to 5.42) and 7.32 (95% confidence interval, 5.97 to 8.97), respectively. Even after adjusting for clinical risk factors, survival remained worse for dialysis patients and those with NDDRI, with hazard ratios of 2.59 (95% confidence interval, 1.92 to 3.49) and 2.51 (95% confidence interval, 2.02 to 3.12), respectively. We conclude that renal insufficiency, both dialysis dependent and non-dialysis dependent, is an independent risk factor for increased mortality and poor long-term survival among patients undergoing coronary angiography.

Overview of the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease. On behalf of the APPROACH investigators.

The Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) is an ongoing prospective data collection initiative that began in January 1995. The cohort for the initiative is all patients undergoing cardiac catheterization in Alberta. Patients are followed longitudinally for the determination of short and long term clinical, economic and quality of life outcomes. The project is producing valuable information on the processes and outcomes of cardiac care in Alberta, and is now being implemented in British Columbia as well. This paper provides an overview of APPROACH with specific attention to the project's general objectives, salient features, database structure and technical specifications. Examples of applied research projects based on APPROACH data are also provided.

Prognostic significance of diabetes as a predictor of survival after cardiac catheterization. APPROACH Investigators. Alberta Provincial Program for Outcome Assessment in Coronary Heart Disease.

PURPOSE: Diabetes is a recognized risk factor for the development of cardiac disease, but its importance as a prognostic factor among patients with known cardiovascular disease is less clear. We evaluated survival in patients with and without diabetes who underwent cardiac catheterization for presumed coronary artery disease. SUBJECTS AND METHODS: We analyzed data from a prospective cohort study that captures detailed clinical information and longitudinal outcomes for all patients who undergo cardiac catheterization in Alberta, Canada. We studied 11,468 patients, 1959 (17%) of whom had diabetes. Logistic regression was used to model predictors of 1-year mortality, and proportional hazards analysis was used to model predictors of survival up to 3 years after cardiac catheterization. RESULTS: One-year mortality was 7.6% for patients with diabetes versus 4.1% for those without diabetes (odds ratio = 1.9, 95% confidence interval [CI]: 1.6 to 2.3). After adjusting for other characteristics of the patients, including comorbid conditions, previous cardiac history, coronary anatomy, and renal function, the odds ratio for 1-year mortality was 1.1 (95% CI: 0.8 to 1.3). Similarly, the adjusted hazard ratio for longer term mortality was 1. 2 (95% CI: 1.0 to 1.4, mean follow-up of 702 days). CONCLUSIONS: These results suggest that there is little or no independent association between diabetes and mortality for up to 3 years after cardiac catheterization. Estimates of short- to intermediate-term prognosis for diabetic patients with coronary artery disease should be based on the presence of other prognostic factors associated with diabetes.

Dealing with missing data in observational health care outcome analyses.

Observational outcome analyses appear frequently in the health research literature. For such analyses, clinical registries are preferred to administrative databases. Missing data are a common problem in any clinical registry, and pose a threat to the validity of observational outcomes analyses. Faced with missing data in a new clinical registry, we compared three possible responses: exclude cases with missing data; assume that the missing data indicated absence of risk; or merge the clinical database with an existing administrative database. The predictive model derived using the merged data showed a higher C statistic (C = 0.770), better model goodness-of-fit as measured in a decile-of-risk analysis, the largest gradient of risk across deciles (46.3), and the largest decrease in deviance (-2 log likelihood = 406.2). The superior performance of the enhanced data model supports the use of this "enhancement" methodology and bears consideration when researchers are faced with nonrandom missing data.

'Primary intention' intracoronary stenting guided by angiography alone: a safe approach.

OBJECTIVE: To examine the outcome of intracoronary stent placement by 'primary intention', guided by angiography alone, and without the use of postprocedural anticoagulation. DESIGN: Prospective, observational study. SETTING: Canadian university teaching hospital. PATIENTS: Patients (n=559) undergoing urgent or elective percutaneous revascularization procedures (n=616) in whom a preprocedural decision to employ coronary stent placement was made. Emergency and bailout stent procedures were excluded. INTERVENTION: Stents were delivered at high pressure (1616 to 1818 kPa) on balloons matched to the proximal reference segment diameter. Adequacy of stent deployment was judged by angiographic criteria alone. Postprocedural medication included acetylsalicylic acid and ticlopidine. Quantitative coronary angiographic analysis was independently performed. Acute procedural outcomes were prospectively collected. Patients were followed for one year. RESULTS: All but one patient had a successful angiographic result. Periprocedural death (0.3%), Q wave myocardial infarction (MI) (0%), non-Q MI (1.6%) and stent thrombosis (0.6%) were uncommon events. At one year, 96% of patients were alive and free of MI, while 12% of patients required repeat target lesion revascularization. CONCLUSION: A primary intention strategy of intracoronary stenting, guided by angiography alone, is a safe and effective approach to percutaneous coronary revascularization.

Primary stenting versus balloon angioplasty in occluded coronary arteries: the Total Occlusion Study of Canada (TOSCA).

BACKGROUND: Balloon angioplasty (PTCA) of occluded coronary arteries is limited by high rates of restenosis and reocclusion. Although stenting improves results in anatomically simple occlusions, its effect on patency and clinical outcome in a broadly selected population with occluded coronary arteries is unknown. METHODS AND RESULTS: Eighteen centers randomized 410 patients with nonacute native coronary occlusions to PTCA or primary stenting with the heparin-coated Palmaz-Schatz stent. The primary end point, failure of sustained patency, was determined at 6-month angiography. Repeat target-vessel revascularization, adverse cardiovascular events, and angiographic restenosis (>50% diameter stenosis) constituted secondary end points. Sixty percent of patients had occlusions of >6 weeks' duration, baseline flow was TIMI grade 0 in 64%, and median treated segment length was 30.5 mm. With 95.6% angiographic follow-up, primary stenting resulted in a 44% reduction in failed patency (10.9% versus 19.5%, P=0.024) and a 45% reduction in clinically driven target-vessel revascularization at 6 months (15.4% versus 8.4%, P=0.03). The incidence of adverse cardiovascular events was similar for both strategies (PTCA, 23.6%; stent, 23.3%; P=NS). Stenting resulted in a larger mean 6-month minimum lumen dimension (1.48 versus 1.23 mm, P<0.01) and a reduced binary restenosis rate (55% versus 70%, P<0.01). CONCLUSIONS: Primary stenting of broadly selected nonacute coronary occlusions is superior to PTCA alone, improving late patency and reducing restenosis and target-vessel revascularization.

An open design, multicentre, randomized trial of percutaneous transluminal coronary angioplasty versus stenting, with a heparin-coated stent, of totally occluded coronary arteries: rationale, trial design and baseline patient characteristics. Total Occlusion Study of Canada (TOSCA) Investigators.

BACKGROUND: Percutaneous transluminal coronary angioplasty (PTCA) of totally occluded coronary arteries is performed in a variety of clinical settings and for a variety of indications. Most commonly it is performed for relief of symptoms of myocardial ischemia. Studies have also suggested that PTCA of occluded arteries beyond the acute phase of myocardial infarction may improve left ventricular function even in the absence of objective evidence of ischemia. One of the major limitations of total occlusion PTCA is a high rate of reocclusion, reported to be as high as 40%. Recently, small studies have suggested that stenting may improve the long term outcome after PTCA of total coronary occlusions. OBJECTIVES: To determine in a prospective, randomized trial whether long term patency and clinical outcome following successful PTCA of a totally occluded coronary can be improved by the use of of a heparin-coated stent. PATIENTS AND METHODS: Subjects were randomly assigned to one of two strategies once the guide wire had crossed the occluded segment of the target artery: PTCA alone, or PTCA followed by insertion of Palmaz-Shatz heparin-coated stent(s). Randomization was stratified according to duration of the coronary occlusion: six weeks or less, and more than six weeks. The primary end-point is failure of sustained patency (Thrombolysis in Myocardial Infarction [TIMI] flow grade less than 3) at six months. Secondary end-points are change in minimal luminal diameter, target vessel revascularization at one year, cardiovascular events at one year, and change in global and regional left ventricular function. BASELINE CHARACTERISTICS: All 410 patients have been randomly assigned to the PTCA alone (n = 208) or PTCA plus stent (n = 202) group. Mean age was 58 +/- 11 years and 18% were female. Prior myocardial infarction had been documented in 67% of patients. The duration of occlusion was six weeks or less in 40% and more than six weeks in 60% of patients. In 64% of patients TIMI flow was grade 0 and in 36% it was grade 1. STUDY IMPLICATIONS: The trial will demonstrate whether the use of a heparin-bonded stent can improve long term patency and clinical outcome in patients undergoing clinically indicated PTCA of totally occluded coronary arteries. If a significant reduction in reocclusion and clinical events is demonstrated, the Total Occlusion Study of Canada (TOSCA) would offer a more effective long term revascularization strategy in future trials testing the open artery hypothesis.

Dynamics of left ventricular apex rotation during angioplasty: a sensitive index of ischemic dysfunction.

BACKGROUND: Apex rotation has been shown to provide a reliable index of the dynamics of left ventricular (LV) twist. In this study, we aimed to characterize twist at baseline and during acute ischemia in 20 patients undergoing percutaneous transluminal coronary angioplasty to the left anterior descending (LAD) artery and to test whether an old myocardial infarction or collateral flow affected twist dynamics. METHODS AND RESULTS: Among patients with no previous infarction, five had no collaterals (group A) and six had angiographically visible collaterals (group B). Previous anterior infarction was present in nine patients (group C). Data were acquired with the LAD angioplasty wire passed beyond the apex using a view aligned with the LV long axis. Frame-by-frame dynamics of apex rotation were measured from the angular movement of the portion of the wire that traversed the apex. Aortic pressure recordings allowed precise temporal definition of the cardiac cycle. Dynamics of apex rotation were measured at fixed intervals until 60 seconds of occlusion and up to 60 seconds of reperfusion. In group A, counterclockwise apex rotation (twist) during ejection of -22.0+/-1.7 degrees (mean+/-SEE) was followed by rapid clockwise rotation (untwist) during isovolumic relaxation. During 60 seconds of ischemia, maximum apex rotation decreased to -8.2+/-2.0 degrees (P<.001 versus baseline). In group B, baseline apex rotation was similar (-26.2+/-6.9 degrees) to that in group A, but ischemia had less effect, with apex rotation values of -17.7+/-3.4 degrees (P<.05 versus group A values). Group C was characterized by reduced baseline apex rotation values (-9.7+/-3.1 degrees, P<.05 versus group A values), with little change observed during ischemia (-8.1+/-2.6 degrees). CONCLUSIONS: Apex rotation, an index of ventricular twist, is sensitive to acute ischemia in patients without previous myocardial infarction. Visible collaterals to the ischemic region attenuate the acute ischemic response at 60 seconds. Previous myocardial infarction causes abnormalities in the baseline twist pattern with no further deterioration at 60 seconds of ischemia.

Relation of pacing-induced coronary resistance vessel dilation to total serum cholesterol and heart rate-blood pressure product.

Coronary risk factors adversely affect coronary resistance vessel dilation to acetylcholine, but little is known about the effect of risk factors on coronary blood flow (CBF) responses to physiologic stimuli. CBF was derived from Doppler flow velocity (0.018-inch Doppler wire) and coronary diameter (quantitative angiography) in response to rapid atrial pacing in 50 patients (mean age 52 +/- 12 years). Patients were prospectively divided into 3 groups based on their angiograms: group 1 (n = 17), normal coronary arteries; group 2 (n = 18), 1-vessel coronary artery disease (CAD) with a smooth study artery; group 3 (n = 15), 1-vessel CAD and an irregular study artery (<20% stenosis). Pacing produced a significant increase in CBF compared with baseline in groups 1 and 2 (34 +/- 40%, 42 +/- 35%, p < 0.0001), respectively, but not in group 3 (21 +/- 33%), but there was no difference in the pacing response among the 3 groups. The increase in CBF to pacing was inversely related to serum cholesterol (p = 0.01) and triglycerides (p = 0.06) and directly related to the increase in heart rate-blood pressure product (p = 0.007). By multivariate analysis, total cholesterol and the increase in double product were the only factors related to the increase in CBF. Increases in CBF to atrial pacing are inversely related to serum total cholesterol and are not related to the angiographic presence of atherosclerosis in patients with mild CAD.

Effect of coronary angioplasty on precordial QT dispersion.

Dispersion of the QT interval is a measure of inhomogeneity of ventricular repolarization. Because ischemia is associated with regional abnormalities of conduction and repolarization, we hypothesized that the surface electrocardiographic interval dispersion would increase in patients with symptomatic coronary artery disease in the absence of myocardial infarction and that successful revascularization would reduce QT interval dispersion. Thirty-seven consecutive patients with ischemia due to 1-vessel coronary artery disease without prior myocardial infarction who underwent percutaneous transluminal coronary angioplasty (PTCA) were evaluated. Standard 12-lead electrocardiograms were performed 24 hours before, 24 hours after, and late (>2 months) after PTCA. Precordial QT interval dispersions were determined from differences in the maximum and minimum corrected QT intervals. Mean QT interval dispersion before PTCA was 60 +/- 9 ms, immediately after PTCA 23 +/- 14 ms (p <0.001), and late after PTCA 29 +/- 18 ms (p <0.001 vs before PTCA). The shortest precordial QT interval increased immediately after PTCA (367 +/- 40 vs 391 +/- 39 ms; p <0.02) and then remained stable late after PTCA (376 +/- 36 ms, p = NS vs immediately after PTCA). Symptomatic recurrent ischemia in 8 patients with documented restenosis increased QT interval dispersion (56 +/- 15 ms [p <0.01] vs 25 +/- 14 ms immediately after PTCA), which decreased again after successful repeat PTCA (22 +/- 13 ms [p <0.01] vs before the second PTCA). QT interval dispersion decreases after successful coronary artery revascularization and increases with restenosis. Therefore, QT interval dispersion may be a marker of recurrent ischemia due to restenosis after PTCA.

Platelet membrane receptor glycoprotein IIb/IIIa antagonism in unstable angina. The Canadian Lamifiban Study.

BACKGROUND: Ligand binding to the platelet membrane receptor glycoprotein (GP) IIb/IIIa, the final and obligatory step to platelet aggregation, can now be inhibited by pharmacological agents. This study was designed to evaluate the potential of lamifiban, a novel nonpeptide antagonist of GP IIb/IIIa, for the management of unstable angina. METHODS AND RESULTS: In a prospective, dose-ranging, double-blind study, 365 patients with unstable angina were randomized to an infusion of 1, 2, 4, or 5 micrograms/min of lamifiban or of placebo. Treatment was administered for 72 to 120 hours. Outcome events were measured during the infusion period and after 1 month. Concomitant aspirin was administered to all patients and heparin to 28% of patients. Lamifiban, all doses combined, reduced the risk of death, nonfatal myocardial infarction, or the need for an urgent revascularization during the infusion period from 8.1% to 3.3% (P = .04). The rates were 2.5%, 4.9%, 3.3%, and 2.4% with increasing doses. At 1 month, death or nonfatal infarction occurred in 8.1% of patients with placebo and in 2.5% of patients with the two high doses (P = .03). The highest dose of lamifiban additionally prevented the need for an urgent intervention. Lamifiban dose-dependently inhibited platelet aggregation. Bleeding times were significantly prolonged with platelet inhibition of > 80%. Major (but neither life-threatening nor intracranial) bleedings occurred in 0.8% of patients with placebo and 2.9% with lamifiban. CONCLUSIONS: The nonpeptide GP IIb/IIIa antagonist lamifiban protected patients with unstable angina from severe ischemic events during a 3- to 5-day infusion and reduced the incidence of death and infarction at 1 month, suggesting considerable promise for this new therapeutic approach.

Clinical management of unstable angina: the place of antithrombins and platelet GP IIb/IIIa receptor blockers.

Unstable angina is a clinical and anatomic mosaic in which platelet aggregation, thrombus formation and fixed and dynamic coronary artery restrictions play variable and changing roles. Emerging medical and mechanical options to deal with each of these components show promise. GP IIb/IIIa receptor blockade is a significant advance over aspirin as all pathways to platelet aggregation are blocked by the new agents. Whether the new antithrombins represent a major advance over heparin is less clear as prothrombin activation is not blocked and rebound is seen as a result. For these new antiplatelet and antithrombin medications, encouragement is based upon small trials. The initial impressions need to be confirmed in larger trials before the role of these expensive new agents can be defined.

A randomized comparison of the effects of gradual prolonged versus standard primary balloon inflation on early and late outcome. Results of a multicenter clinical trial. Perfusion Balloon Catheter Study Group.

BACKGROUND: Observational studies have suggested that prolonged balloon inflation during coronary angioplasty is associated with a high clinical success rate. This randomized clinical trial sought to evaluate the impact of primary gradual and prolonged inflations versus standard short dilatations in patients undergoing elective angioplasty. METHODS AND RESULTS: In phase 1 of the study, patients were randomized to receive two to four standard (1 minute) dilatations or one or two prolonged (15 minutes) dilatations after a perfusion balloon had been placed across a single target lesion. Patients with unsuccessful angiographic appearance after phase 1 dilatations had further dilatations in phase 2. Patients were followed for 6 to 12 months after the procedure. Of 478 patients, 242 received a median of one prolonged dilatation of 15 minutes' duration, and 236 received three dilatations for a median of 1 minute. Patients assigned to prolonged dilatations had a higher success rate (< or = 50% residual visual stenosis) (95% versus 89%; P = .016), less severe residual stenosis by quantitative angiography (median [25th and 75th percentiles], 35% [26%, 42%] versus 38% [30%, 46%]; P = .001), and a lower rate of major dissections (3% versus 9%; P = .003) at the end of phase 1. A total of 114 patients had further dilatations in phase 2-43 in the prolonged arm and 71 in the standard arm. The final procedural success rate was 98% with both primary dilatation strategies, which included additional maneuvers such as prolonged dilatations in the patients randomized to the primary standard dilatation. Overall, 320 of 416 patients (77%) who were discharged after a successful procedure without any in-hospital event (death, myocardial infarction, coronary artery bypass graft surgery, abrupt closure, or repeat angioplasty in target vessel) returned for follow-up angiography. The restenosis rate (> 50% residual visual stenosis) was 44% (95% confidence interval, 37% to 52%) in the prolonged dilatation group and 44% (36% to 52%) in the standard dilatation group. The primary angiographic end point of failure at the end of phase 1, abrupt closure, or restenosis throughout the study period was similar in both groups (prolonged, 51%; standard, 49%; P = .62). The secondary end point of absence of clinical events (death, nonfatal myocardial infarction, coronary artery bypass graft surgery, or repeat angioplasty in target vessel) also was similar (prolonged, 66%; standard, 74%; P = .15). CONCLUSIONS: Primary gradual and prolonged dilatations caused less arterial trauma with a modestly larger arterial lumen compared with standard dilatations. This initial improvement in angiographic appearance did not lead to a significant reduction in restenosis or clinical adverse events during follow-up.

An optical device to measure the dynamics of apex rotation of the left ventricle.

Systolic counterclockwise rotation of the left ventricular apex with respect to the base has been defined as left ventricular (LV) twist or torsion. If rotation of the base during systole is small, we hypothesized that the dynamics of twist can be well characterized through the measurement of apical rotation alone. A device was designed to measure apical rotation in a simpler, more direct fashion, providing continuous high-fidelity dynamic measurements. The device consists of a light source, a position-sensitive diode, and a small rotating mirror that is coupled to the apex of the heart by a wire. As the wire rotates, apical rotation (measured in degrees) can be calculated from the position of the deflected light beam. The timing of apical rotation was compared with simultaneous recordings of electrocardiogram, LV pressure, and LV diameter measurements. An initial clockwise rotation (untwist) of 4 +/- 2 degrees (SD) occurred during isovolumic contraction followed by counterclockwise rotation (twisting) through ejection, reaching maximum apical rotation of -15 degrees just before the end of systole. Rapid untwisting during isovolumic relaxation was shown with near-complete dissipation of twist by the first one-third of the diastolic filling period. Caval occlusion caused a downward and leftward shift of the pressure-apical rotation loops, and more twist/untwist was seen to occur during the respective isovolumic contraction and relaxation periods. We conclude that this device provides precise timing and definition of rapid changes during isovolumic contraction and relaxation, confirms results obtained by more laborious methods, and provides an easy method to measure the dynamics of apical rotation continuously during interventions such as load changes.