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2.
J Am Coll Cardiol ; 37(1): 19-25, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11153737

ABSTRACT

OBJECTIVES: We wished to determine the effect of post-infarct management strategy on event rates (death or recurrent nonfatal myocardial infarction [MI]) in patients who evolved non-Q-wave MI (NQMI) following thrombolytic therapy. BACKGROUND: Patients who evolve NQMI following thrombolytic therapy are often considered to be at high risk and are frequently managed with routine early invasive testing despite a lack of data supporting improved outcome. METHODS: The Veterans Affairs Non-Q-Wave Infarction Strategies In-Hospital (VANQWISH) study included 115 patients who evolved NQMI following thrombolytic therapy. We compared the event rates in patients randomized to routine early coronary angiography with those in patients randomized to a conservative strategy of noninvasive functional assessment, with angiography reserved for patients with spontaneous or induced ischemia. RESULTS: During an average follow-up of 23 months, 19 of 58 patients (33%) randomized to the invasive management strategy died or suffered recurrent nonfatal MI, compared with 11 of 57 patients (19%) randomized to the conservative strategy (p = 0.152). Equivalent numbers of patients were subjected to revascularization (percutaneous transluminal coronary angioplasty or coronary artery bypass graft). There were more deaths in the invasive management group than in the conservative management group (11 vs. 2). Excess deaths could not be attributed to periprocedural mortality. CONCLUSIONS: Overall event rates (death or recurrent nonfatal MI) are comparable with conservative and invasive strategies in patients who evolve NQMI following thrombolytic therapy. Mortality rate in patients managed conservatively is low (3.5%), and routine invasive management may be associated with an increased risk of death.


Subject(s)
Coronary Angiography , Electrocardiography , Myocardial Infarction/therapy , Myocardial Revascularization , Thrombolytic Therapy , Aged , Combined Modality Therapy , Female , Hospitals, Veterans , Humans , Male , Middle Aged , Myocardial Infarction/diagnosis , Myocardial Infarction/mortality , Outcome and Process Assessment, Health Care , Recurrence , Risk Assessment , Survival Analysis
3.
J Am Coll Cardiol ; 35(3): 583-91, 2000 Mar 01.
Article in English | MEDLINE | ID: mdl-10716458

ABSTRACT

OBJECTIVES: This study sought to determine the safety, feasibility and outcome of local delivery of cytochalasin B at the site of coronary angioplasty. BACKGROUND: Previous failures in the pharmacologic prevention of restenosis may have been related to inadequate dosing at the angioplasty site as a result of systemic drug administration. Alternatively, although previous experimental protocols have typically targeted control of excess tissue growth (intimal hyperplasia), it now appears that overall arterial constriction (vascular remodeling) is the major contributor to late lumen loss. Cytochalasin B inhibits the polymerization of actin and has proved to be a potent inhibitor of vascular remodeling in animal models. METHODS: In this phase I, multicenter, randomized, controlled trial, cytochalasin B (or matching placebo) was administered to the site of a successful balloon angioplasty using a microporous local delivery infusion balloon. RESULTS: The rate of drug delivery at a constant infusion pressure varied significantly from patient to patient (range 1.7 to 20.2 ml/min), perhaps related to a variable constricting effect of the atherosclerotic plaque on the infusion balloon. The minimal stenosis diameter after the procedure was slightly better in the active drug group (1.86 +/- 0.44 vs. 1.49 +/- 0.63 mm, p < 0.03), but this difference was not seen at four to six weeks. Although the study was not powered for clinical outcomes (n = 43), the combined end point (death, nonfatal infarction or repeat revascularization) was encountered in 20% of the patients receiving cytochalasin B and in 38% of the patients receiving placebo. Clinical restenosis occurred in 18% of the treatment group and 22% of the placebo group. There were no significant differences between groups in biochemical or electrocardiographic variables. CONCLUSIONS: Cytochalasin B can be safely administered by local delivery after successful coronary angioplasty and warrants further study of its efficacy in reducing restenosis.


Subject(s)
Angioplasty, Balloon, Coronary , Catheterization, Peripheral , Coronary Disease/therapy , Coronary Vessels/drug effects , Cytochalasin B/administration & dosage , Drug Delivery Systems/methods , Adult , Aged , Aged, 80 and over , Coronary Angiography , Coronary Disease/diagnostic imaging , Cytochalasin B/therapeutic use , Electrocardiography , Feasibility Studies , Female , Humans , Infusions, Intra-Arterial/methods , Male , Middle Aged , Myocardial Revascularization , Safety , Treatment Outcome
4.
Am Heart J ; 138(6 Pt 1): 1118-25, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10577443

ABSTRACT

BACKGROUND: The arterial access required during most invasive vascular procedures provides a common source of complications and morbidity. This problem has been made worse by recent trends in earlier ambulation and more aggressive antihemostatic drug regimens. Despite these trends, no randomized trials have been reported comparing the 3 most commonly used techniques in achieving hemostasis at the arterial puncture site. METHODS: A cohort of 400 patients undergoing catheterization laboratory procedures were randomly assigned to 1 of 3 groups of arterial compression: manual compression, mechanical clamp, and pneumatic compression device. Standard requirements of the trial included uniformity in initial compression times, patient instructions, nursing follow-up, and timing of ambulation as well as a structured interview and physical examination at 24 hours. RESULTS: Prolonged compression was required in 13% of the manual group, 20% of the clamp group, and 35% of the pneumatic group (P <.0001). In-lab bleeding was more common in the pneumatic group (3%, 4%, and 16%, respectively, P <.0001), as was the need for an alternate compression technique (1%, 1%, and 27%, P <.0001). The groups also differed in respect to mean hematoma size (3.9 cm(2), 7.8 cm(2), and 19.8 cm(2), P =.036) and level of discomfort during compression (1.9, 2.2, and 3.1 on a 1- to 10-point scale, P <.0001). Comparable findings were observed in the subgroup of patients eligible for outpatient procedures. CONCLUSIONS: Use of the pneumatic compression device leads to longer compression times, greater discomfort, more bleeding, and larger hematomas. Differences between manual compression and the mechanical clamp were more subtle but tend to favor use of the manual technique.


Subject(s)
Cardiac Catheterization , Hemostatic Techniques , Female , Humans , Male , Middle Aged , Prospective Studies
5.
J Am Coll Cardiol ; 33(3): 883-91, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10080494

ABSTRACT

OBJECTIVES: To assess whether thermodilution cardiac output determination based on measurement of injectate temperature in vivo leads to more accurate and precise estimates and to study the influence of chilled injectate on test performance. BACKGROUND: Cardiac output measurement via right heart catheterization is used extensively for hemodynamic evaluation in a variety of diagnostic, perioperative and critical care settings. Maximizing accuracy is essential for optimal patient care. METHODS: This prospective study of 960 thermodilution cardiac output measurements was conducted using conventional and dual thermistor techniques. Specialized dual thermistor right heart catheters were constructed using a second thermistor positioned to measure injectate temperature in vivo just prior to entry into the right atrium. To eliminate interinjection variability, a custom set-up was developed that permitted output measurement using both techniques simultaneously. Both ambient temperature injections and cooled injections were investigated. RESULTS: The dual thermistor technique demonstrated significantly less measurement variability than the conventional technique for both ambient temperature (precision = 0.41 vs. 0.55 L/min, p < 0.001) and cooled (precision = 0.35 vs. 0.43 L/min, p = 0.01) injections. Similarly, the average range of cardiac output values obtained during five sequential injections in each patient was less using the dual thermistor approach (1.05 vs. 1.55 L/min, p < 0.001). The use of cooled injectate reduced the mean error of the dual thermistor technique but actually increased the mean error of the conventional technique. Even with ambient temperature injections, injectate warming during catheter transit varied considerably and unpredictably from injection to injection (2 SD range = -0.22 to 5.74 degrees C). Conventional ambient temperature and cooled measurements significantly overestimated Fick cardiac output measurements by 0.32 and 0.50 L/min, respectively (p < 0.001). In contrast, dual thermistor measurements were statistically similar (-0.08 and -0.08 L/min, p = 0.34) to Fick measurements. CONCLUSIONS: This new dual thermistor approach results in a significant improvement in both precision and accuracy of thermodilution cardiac output measurement.


Subject(s)
Cardiac Catheterization/instrumentation , Cardiac Output/physiology , Cardiovascular Diseases/diagnosis , Thermodilution , Cardiovascular Diseases/physiopathology , Equipment Design , Female , Heart Atria/physiopathology , Humans , Male , Middle Aged , Prospective Studies , Reproducibility of Results , Temperature , Thermodilution/instrumentation , Thermodilution/standards
6.
Am Heart J ; 137(2): 274-83, 1999 Feb.
Article in English | MEDLINE | ID: mdl-9924161

ABSTRACT

OBJECTIVES: Thrombosis is a major contributor to complications associated with coronary interventions. It is unclear whether patients who have undergone angioplasty are predisposed to thrombus formation because of underlying perturbations in their hemostatic equilibrium. METHODS: Concentration or activity was measured for 14 plasma proteins involved in the coagulation, fibrinolytic, and inhibitory systems. Baseline systemic measurements were compared between patients undergoing balloon angioplasty (n = 15) and normal subjects (n = 32), with sampling repeated at the end of the procedure. To better assess the local hemostatic environment near the site of dilation, intracoronary arterial samples were also obtained just proximal and distal to the dilated stenosis. RESULTS: Multiple differences in measured coagulation proteins were found at baseline between the angioplasty candidates and control subjects, including higher mean concentration of plasma fibrinogen (P <.001) and lower high-molecular-weight kininogen concentration (P <.01) and factor XII activity (P <.01). Concentrations of the inhibitory proteins antithrombin III and protein S also differed significantly (P <.001 and P <.01, respectively), with a trend toward lower protein C concentration as well (P <.05). Finally, heightened fibrinolysis was suggested by a marked increase in mean plasma d-dimer concentration in the angioplasty candidates (293 +/- 191 ng/mL vs 116 +/- 31 ng/mL, P <.01), with a more modest increase in tissue plasminogen activator (P <.05) and decrease in alpha2-antiplasmin (P <.001). Importantly, none of the parameters obtained during the procedure differed significantly from samples obtained before and after angioplasty, and no translesional gradients were observed. CONCLUSIONS: Patients with active ischemic syndromes who are considered candidates for coronary angioplasty demonstrate significant and multiple alterations in their coagulation, inhibitory, and fibrinolytic systems. However, no further changes were observed during coronary dilation, either systemically or locally, after pretreatment with typical doses of heparin and aspirin.


Subject(s)
Angioplasty, Balloon, Coronary , Blood Coagulation Factors/metabolism , Blood Coagulation/physiology , Coronary Disease/therapy , Coronary Thrombosis/blood , Aspirin/therapeutic use , Coronary Disease/blood , Coronary Thrombosis/prevention & control , Coronary Thrombosis/therapy , Fibrinolytic Agents/therapeutic use , Heparin/therapeutic use , Humans , Male , Middle Aged , Premedication , Risk Factors
7.
Cathet Cardiovasc Diagn ; 45(2): 191-201, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9786402

ABSTRACT

Angioscopy represents a diagnostic tool with the unique ability of assessing the true color of intravascular structures. Current angioscopic interpretation is entirely subjective, however, and the visual interpretation of color has been shown to be marginal at best. The quantitative colorimetric angioscopic analysis system permits the full characterization of angioscopic color using two parameters (C1 and C2), derived from a custom color coordinate system, that are independent of illuminating light intensity. Measurement variability was found to be low (coefficient of variation = 0.06-0.64%), and relatively stable colorimetric values were obtained even at the extremes of illumination power. Variability between different angioscopic catheters was good (maximum difference for C1, 0.022; for C2, 0.015). Catheter flexion did not significantly distort color transmission. Although the fiber optic illumination bundle was found to impart a slight yellow tint to objects in view (deltaC1 = 0.020, deltaC2 = 0.024, P < 0.0001) and the imaging bundle in isolation imparted a slight red tint (deltaC1 = 0.043, deltaC2 = -0.027, P < 0.0001), both of these artifacts could be corrected by proper white balancing. Finally, evaluation of regional chromatic characteristics revealed a radially symmetric and progressive blue shift in measured color when moving from the periphery to the center of an angioscopic image. An algorithm was developed that could automatically correct 93.0-94.3% of this error and provide accurate colorimetric measurements independent of spatial location within the angioscopic field. In summary, quantitative colorimetric angioscopic analysis provides objective and highly reproducible measurements of angioscopic color. This technique can correct for important chromatic distortions present in modern angioscopic systems. It can also help overcome current limitations in angioscopy research and clinical use imposed by the reliance on visual perception of color.


Subject(s)
Angioscopy , Color , Colorimetry , Image Interpretation, Computer-Assisted , Algorithms , Catheterization , Humans , Image Processing, Computer-Assisted
8.
Ann Intern Med ; 128(12 Pt 1): 965-74, 1998 Jun 15.
Article in English | MEDLINE | ID: mdl-9625682

ABSTRACT

BACKGROUND: Empirical scores, computerized ST-segment measurements, and equations have been proposed as tools for improving the diagnostic performance of the exercise test. OBJECTIVE: To compare the diagnostic utility of these scores, measurements, and equations with that of visual ST-segment measurements in patients with reduced workup bias. DESIGN: Prospective analysis. SETTING: 12 university-affiliated Veterans Affairs Medical Centers. PATIENTS: 814 consecutive patients who presented with angina pectoris and agreed to undergo both exercise testing and coronary angiography. MEASUREMENTS: Digital electrocardiographic recorders and angiographic calipers were used for testing at each site, and test results were sent to core laboratories. RESULTS: Although 25% of patients had previously had testing, workup bias was reduced, as shown by comparison with a pilot study group. This reduction resulted in a sensitivity of 45% and a specificity of 85% for visual analysis. Computerized measurements and visual analysis had similar diagnostic power. Equations incorporating nonelectrocardiographic variables and either visual or computerized ST-segment measurement had similar discrimination and were superior to single ST-segment measurements. These equations correctly classified 5 more patients of every 100 tested (areas under the receiver-operating characteristic curve, 0.80 for equations and 0.68 for visual analysis; P < 0.001) in this population with a 50% prevalence of disease. CONCLUSIONS: Standard exercise tests had lower sensitivity but higher specificity in this population with reduced work-up bias than in previous studies. Computerized ST-segment measurements were similar to visual ST-segment measurements made by cardiologists. Considering more than ST-segment measurements can enhance the diagnostic power of the exercise test.


Subject(s)
Coronary Disease/diagnosis , Electrocardiography , Exercise Test/methods , Image Processing, Computer-Assisted , Adult , Aged , Angina Pectoris/etiology , Bias , Coronary Angiography , Coronary Disease/physiopathology , Hemodynamics , Humans , Middle Aged , Prospective Studies , ROC Curve , Sensitivity and Specificity
9.
Am J Cardiol ; 81(10): 1196-9, 1998 May 15.
Article in English | MEDLINE | ID: mdl-9604944

ABSTRACT

Eight consecutive patients with unstable angina underwent intravascular ultrasound imaging of the culprit artery with measurements recorded at the stenosis and at an adjacent reference site. In all patients, total artery cross-sectional area was smaller at the stenosis site than at the reference site, indicating that a structural change in the artery wall due to a constrictive process appears to contribute to the worsening of stenosis severity associated with unstable angina.


Subject(s)
Angina, Unstable/etiology , Angina, Unstable/pathology , Coronary Disease/complications , Coronary Disease/pathology , Adult , Aged , Angina, Unstable/diagnostic imaging , Coronary Angiography , Coronary Disease/diagnostic imaging , Female , Humans , Male , Middle Aged , Severity of Illness Index
10.
Am J Cardiol ; 81(8): 1004-12, 1998 Apr 15.
Article in English | MEDLINE | ID: mdl-9576161

ABSTRACT

Automated devices have regularly replaced manual sphygmomanometry for the determination of blood pressure not only in homes and clinics, but also in emergency and critical care settings. Few studies exist that correctly assess the accuracy of these devices, and even fewer that specifically compare commercially available units that rely on different physiologic events for measurement. Six hundred pressure measurements were obtained from 120 subjects using 1 of 3 randomly selected blood pressure monitors. In addition, central arterial pressure measurements were obtained simultaneously and directly from the ascending aorta of each subject. Overall, these devices tended to overestimate diastolic (+2.5 mm Hg, p < 0.0001) and mean (+3.8 mm Hg, p < 0.0001) pressures, but not systolic (+0.7 mm Hg, p = NS) pressure. Compared with the other 2 devices, device I, relying on oscillometric detection, demonstrated a significantly smaller mean absolute error for diastolic pressure (4.9 +/- 3.0 vs 7.0 +/- 4.8 and 6.2 +/- 5.3 mm Hg, p < 0.0001) and mean pressure (4.0 +/- 3.2 vs 7.8 +/- 5.9 and 8.6 +/- 7.5 mm Hg, p < 0.0001), and a trend toward smaller error with systolic pressure (6.8 +/- 6.5 vs 7.3 +/- 6.8 and 8.0 +/-5.6 mm Hg, p = 0.19). Clinically significant (+/-10 mm Hg) errors were common with each device (24.8% overall), but serious (+/-20 mm Hg) errors were unusual (3.2%) and did not occur at all with device I during diastolic and mean pressure measurement. All of the devices tested could be expected to perform satisfactorily in most clinical settings provided that an average error of 4.0 to 8.6 mm Hg is tolerable. This level of accuracy typically extended throughout the range of pressures anticipated in most noncritical clinical situations. As implemented in the devices tested, noninvasive measurement by oscillometry with stepped deflation is more accurate than automated auscultation.


Subject(s)
Blood Pressure Determination/methods , Blood Pressure/physiology , Adult , Aged , Aorta, Thoracic , Automation , Blood Pressure Determination/instrumentation , Cardiovascular Diseases/physiopathology , Catheterization, Peripheral , Humans , Male , Middle Aged , Random Allocation , Reproducibility of Results
11.
Circulation ; 96(9): 3030-41, 1997 Nov 04.
Article in English | MEDLINE | ID: mdl-9386172

ABSTRACT

BACKGROUND: Angioscopy surpasses other diagnostic tools, such as angiography and intravascular ultrasound, in detecting arterial thrombus. This capability arises in part from the unique ability of angioscopy to assess true color during imaging. In practice, hardware-induced chromatic distortions and the subjectivity of human color perception substantially limit the theoretic potential of angioscopic color. We used a novel application of tristimulus colorimetry to quantify thrombus color to both aid in its detection and assess its composition. METHODS AND RESULTS: A series of human thrombus models were constructed in vitro. Spatial homogeneity was ensured by light and electron microscopy. Quantitative colorimetric angioscopic analysis demonstrated excellent measurement reproducibility (mean difference, 0.07% to 0.17%), unaffected by illuminating light intensity (coefficient of variation, 0.21% to 3.67%). Colorimetric parameters C1 and C2 were strongly correlated (r=.99, P<.0001) with thrombus erythrocyte concentration. Principal components analysis transformed these parameters into a single value, the thrombus erythrocyte index, with little (0.06%) loss of content. Measured and predicted concentrations were similar (mean difference, 0.16 erythrocytes per 1 ng). Randomly ordered images were also subjected to visual analysis by three experienced angioscopists, with suboptimal levels of both intraobserver (mean kappa=0.63) and interobserver (mean kappa=0.48) agreement. In addition, visual ranking resulted in a Kendall rank coefficient of 0.72 to 0.76 versus a perfect 1.00 from quantitative measurement. CONCLUSIONS: Quantitative colorimetric angioscopic analysis provides a new, objective, and reproducible analytic tool for assessing angioscopic images of human thrombus. Even under ideal circumstances, experienced angioscopists do a poor job of assessing color (and therefore composition) of human thrombi. This technique can, for the first time, provide quantitative information of thrombus composition during routine diagnostic imaging.


Subject(s)
Coronary Thrombosis/diagnosis , Angioscopy , Color , Colorimetry , Humans
12.
J Am Coll Cardiol ; 30(2): 444-51, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9247517

ABSTRACT

OBJECTIVES: This study investigated the efficacy of four different methods of arterial puncture site management during recovery from invasive cardiac procedures. The primary goals were less patient discomfort and improved clinical outcome. BACKGROUND: The increasing use of outpatient catheterization, large interventional devices and potent periprocedural anticoagulation regimens has made the reduction of groin complications a high priority. Despite these trends, there are no randomized trials comparing commonly used techniques in treating the catheter entry site for the first few hours after the procedure. METHODS: Four-hundred consecutive patients undergoing catheterization laboratory procedures were randomly assigned to one of four dressing techniques applied after achieving hemostasis: a sandbag placed over the site; a pressure dressing constructed from surgical gauze and elastic tape; a commercially available compression device; and no use of compressive dressing. Of these 400 patients, 171 would have been eligible for outpatient procedures in the absence of geographic constraints. The dressings were removed, and ambulation was encouraged 5 h after sheath removal. Uniform initial compression times, patient instructions, nursing follow-up and a structured interview and physical examination at 24 h were used. RESULTS: The level of patient discomfort before and after dressing removal, as well as site tenderness at 24-h follow-up, was statistically similar in all four groups. Hematomas (typically small) and areas of ecchymosis were observed in 58 and 122 patients, respectively, but both their frequency and size were equally represented in each group. Important adverse events were confined to bleeding, rated as mild in 5.8%, moderate in 0.8% and severe in 0.6% of patients. Again, all four groups were statistically similar. Comparable findings were observed in the subgroup of patients eligible for outpatient procedures. CONCLUSIONS: Despite an increase in inconvenience and expense, none of the three compression techniques that were investigated improved patient satisfaction or outcome. Therefore, the routine use of compression dressings after invasive cardiac procedures cannot be recommended.


Subject(s)
Cardiac Catheterization , Hemostatic Techniques , Ecchymosis/etiology , Female , Hematoma/etiology , Hemorrhage/prevention & control , Humans , Male , Middle Aged , Occlusive Dressings , Patient Acceptance of Health Care , Treatment Outcome
13.
J Am Coll Cardiol ; 27(6): 1398-405, 1996 May.
Article in English | MEDLINE | ID: mdl-8626950

ABSTRACT

OBJECTIVES: This study investigates whether repeat coronary interventions, applied over an extended time period, can successfully curtail the progression of ischemic symptoms and angiographic lumen narrowing. BACKGROUND: Coronary artery disease is a chronic and generally progressive disorder, and potential treatment strategies should be examined and compared with this chronicity in mind. Percutaneous interventional revascularization procedures could theoretically be useful in controlling progression of the disease through repeated use as new coronary lesions arise. However, the outcome of this long-term management concept has not previously been subjected to detailed investigation. METHODS: From a consecutive series of 4,357 interventional cardiac procedures, 544 patients were identified who received two or more interventions during the 13-year study period. These patients were categorized into one of three groups: restenosis (repeat interventions limited to the same target segment, n = 261), new stenosis (all repeat interventions directed to stenoses not previously treated, n = 155) or both (repeat interventions directed both to the same and to different target lesions, n = 128). RESULTS: Two to five procedures were performed per patient; the time period (mean +/- SD) separating each procedure was significantly less (p < 0.0001) for the restenosis group (4.2 +/- 2.3 months) than for the new stenosis (24.2 +/- 23.5 months) or the "both" groups (11.4 +/- 11.0 months). Despite the need for repeat procedures, the severity of angina (mean New York Heart Association functional class 1.6 +/- 0.9) after 6.2 +/- 2.3 years of follow-up was substantially better than before the initial procedure (mean functional class 3.2 +/- 0.8), with a similar magnitude of change found in all three groups. This long-term functional improvement was mirrored by a corresponding anatomic improvement, with the mean number of diseased vessels remaining constant at the time of each procedure (1.5 +/- 0.7, 1.5 +/- 0.7 and 1.6 +/- 0.7, respectively, for the first, second and third procedures, p = NS). The restenosis and the new stenosis groups also demonstrated statistically similar annual rates of mortality (1.9% vs. 1.8%) and coronary surgery (2.3% vs. 2.6%), although the restenosis group had a lower rate of infarction (1.4% vs. 3.2%, p = 0.002). CONCLUSIONS: Repeat interventional treatment of newly acquired stenoses provides a rational approach for the long-term management of chronic coronary artery disease. In addition to yielding a favorable late outcome, the use of this strategy can result in sustained functional improvement and can check the progression of clinically significant stenoses.


Subject(s)
Coronary Disease/therapy , Angioplasty, Balloon, Coronary , Atherectomy, Coronary , Female , Follow-Up Studies , Humans , Male , Methods , Middle Aged , Patient Care Planning , Recurrence
14.
Circulation ; 93(6): 1123-32, 1996 Mar 15.
Article in English | MEDLINE | ID: mdl-8653832

ABSTRACT

BACKGROUND: Clinical restenosis after balloon angioplasty can be categorized by use of dichotomous terms based on the presence or absence of recurrent myocardial ischemia. In contrast, recent investigations have concluded that late luminal renarrowing, documented through angiographic imaging, occurs to a variable extent in nearly all stenoses. This process has been characterized by a gaussian or normal frequency distribution, with restenosis simply representing an extreme form of this delayed remodeling. In the current study, frequency distribution analysis was used to examine the process of coronary restenosis in a large cohort of patients at risk. METHODS AND RESULTS: Quantitative coronary angiographic analysis was applied to 9279 cineangiograms obtained in 3093 patients before and immediately after angioplasty and after 6-month follow-up. Late loss, defined as the change in minimum lumen diameter of the target stenosis from postdilation to follow-up, did not statistically conform to a normal distribution (P<.0001 by both chi2 statistic and Kolmogorov-Smirnov test), even after the exclusion of the 236 stenoses that displayed total occlusions at follow-up angiography. Examination of deviation from a normal curve revealed an excessively high frequency of stenoses that experienced either little change (0.0+/-0.3 mm) or marked change (1.0 to 2.0 mm) in late loss, with a low frequency of stenoses with intermediate values (0.3 to 1.0 mm). Similarly, although the distribution of percent diameter stenosis of the target lesion was statistically normal immediately after dilation, this gaussian distribution disappeared during the follow-up period. Other angiographic indexes of restenosis also failed to approximate a normal curve. In an attempt to improve the goodness of fit, a probabilistic model of late loss was created on the basis of deconvolution of the observed data distribution. Two theoretical, discrete populations of stenoses were identified, one with and one without overall late luminal narrowing. Unlike the gaussian distribution, this model provided a good representation of the observed data (P=NS for lack of fit). CONCLUSIONS: The frequency distributions of angiographic indexes of restenosis often superficially resemble a gaussian curve, an appearance that is artifactually enhanced by the measurement imprecision of current quantitative techniques. Nevertheless, standard indexes of coronary restenosis fail to conform statistically to a normal distribution. The pattern of deviations observed supports the possible existence of discrete subpopulations of lesions, each with a different propensity toward the development of restenosis after coronary intervention.


Subject(s)
Angioplasty, Balloon, Coronary/adverse effects , Coronary Disease/etiology , Adult , Aged , Coronary Angiography , Female , Humans , Male , Middle Aged , Recurrence
15.
Circulation ; 91(8): 2174-83, 1995 Apr 15.
Article in English | MEDLINE | ID: mdl-7697846

ABSTRACT

BACKGROUND: Computerized quantitative coronary angiography (QCA) has fundamentally altered our approach to the assessment of coronary interventional techniques and strategies aimed at the prevention of recurrence and progression of stenosis. It is essential, therefore, that the performance of QCA systems, upon which much of our scientific understanding has become integrally dependent, is evaluated in an objective and uniform manner. METHODS AND RESULTS: We validated 10 QCA systems at core laboratories in North America and Europe. Cine films were made of phantom stenoses of known diameter (0.5 to 1.9 mm) under four experimental conditions: in vivo (coronary arteries of pigs) calibrated at the isocenter or by use of the catheter as a scaling device and in vitro with 50% contrast and 100% contrast. The cine films were analyzed by each automated QCA system without observer interaction. Accuracy and precision were taken as the mean and SD of the signed differences between the phantom stenoses, and the measured minimal luminal diameters and the correlation coefficient (r), the SEE, the y intercept, and the slope were derived by their linear regression. Performance of the 10 QCA systems ranged widely: accuracy, +0.07 to +0.31 mm; precision, +/- 0.14 to +/- 0.24 mm; correlation (r), .96 to .89; SEE, +/- 0.11 to +/- 0.16 mm; intercept, +0.08 to +0.31 mm; and slope, 0.86 to 0.64. CONCLUSIONS: There is a marked variability in performance between systems when assessed over the range of 0.5 to 1.9 mm. The range of accuracy, intercept, and slope values of this report indicates that absolute measurements of luminal diameter from different multicenter angiographic trials may not be directly comparable and additionally suggests that such absolute measurements may not be directly applicable to clinical practice using an on-line QCA system with a different edge detection algorithm. Power calculations and study design of angiographic trials should be adjusted for the precision of the QCA system used to avoid the risk of failing to detect small differences in patient populations. This study may guide the fine-tuning of algorithms incorporated within each system and facilitate the maintenance of high standards of QCA for scientific studies.


Subject(s)
Coronary Angiography/methods , Coronary Disease/diagnostic imaging , Image Processing, Computer-Assisted/standards , Algorithms , Animals , Calibration , Coronary Angiography/instrumentation , Coronary Angiography/standards , Humans , Image Processing, Computer-Assisted/instrumentation , Models, Cardiovascular , Models, Structural , Reproducibility of Results , Swine
16.
Med Prog Technol ; 21(1): 39-46, 1995.
Article in English | MEDLINE | ID: mdl-7791691

ABSTRACT

Colors in video representations of angioscopic images are up until now described by an human observer. Differences in settings of the monitor and the inherent poor ability of the human eye to classify colors objectively results in a very poor intraobserver as well as interobserver variability. A PC-based method is described to measure colors in a video image and to present the results in a novel C-diagram. Results with this method for standard calibrated colors are given. Possible sources of error are discussed and methods to minimize these errors are presented.


Subject(s)
Angioscopy , Colorimetry/methods , Image Processing, Computer-Assisted/methods , Video Recording , Algorithms , Calibration , Evaluation Studies as Topic , Microcomputers , Observer Variation
17.
J Am Coll Cardiol ; 22(3): 714-9, 1993 Sep.
Article in English | MEDLINE | ID: mdl-8354803

ABSTRACT

OBJECTIVES: This study was undertaken to determine whether early successful thrombolysis can reverse infarct-associated mitral valve dysfunction. BACKGROUND: Mitral regurgitation is a common complication of acute myocardial infarction and has been shown to adversely affect both short- and long-term prognosis. Although anecdotal reports have suggested that reperfusion of the infarct-related artery may restore normal function to the mitral valve, this theory has not been subjected to formal investigation. METHODS: Patients with total or partial obstruction of the infarct-related artery received intravenous thrombolytic therapy with either streptokinase or recombinant tissue-type plasminogen activator within 7 h of symptom onset (mean 4.8 h) as part of the Thrombolysis in Myocardial Infarction (TIMI) Phase I trial. Repeat coronary angiography assessed arterial patency at 90 min and 10 days after attempted reperfusion. The presence and severity of mitral regurgitation were determined by contrast ventriculography both before thrombolysis and before hospital discharge. RESULTS: Overall, 21 (16%) of the 132 study patients exhibited mitral regurgitation on either their initial or their predischarge ventriculogram. The proportion of infarct-related arteries found to be patent (TIMI flow grade 2 or 3) was statistically similar in patients with and without mitral regurgitation during each angiographic evaluation period (initial, 90 min and 10 days). Although coronary artery perfusion increased overall during sequential measurement (mean TIMI grade was 0.4 +/- 0.6 initially, 1.5 +/- 1.3 at 90 min and 2.2 +/- 1.0 at 10 days), the pattern of reperfusion observed could not predict an increase or decrease in regurgitant severity (p = NS). Early mitral regurgitation resolved in 57% of patients by 10 days, but this resolution appeared independent of the presence or absence of improved coronary perfusion (60% vs. 50%). The development of new regurgitation during the recovery period (6%) was also unrelated to improved perfusion (7% vs. 4%). CONCLUSIONS: Acute mitral regurgitation developing during myocardial infarction shows frequent changes in its presence or severity during the 1st 10 days, appears independent of coronary artery patency both early and late after thrombolysis and cannot be reliably treated by improving arterial perfusion with thrombolytic agents.


Subject(s)
Mitral Valve Insufficiency/drug therapy , Myocardial Infarction/drug therapy , Thrombolytic Therapy , Acute Disease , Adult , Aged , Analysis of Variance , Cardiac Catheterization , Chi-Square Distribution , Coronary Angiography , Female , Heart Ventricles/diagnostic imaging , Humans , Male , Middle Aged , Mitral Valve Insufficiency/diagnostic imaging , Mitral Valve Insufficiency/epidemiology , Mitral Valve Insufficiency/etiology , Myocardial Infarction/complications , Myocardial Infarction/diagnostic imaging , Myocardial Infarction/epidemiology , Recombinant Proteins/therapeutic use , Thrombolytic Therapy/statistics & numerical data , Tissue Plasminogen Activator/therapeutic use
18.
Ann Intern Med ; 117(1): 10-7, 1992 Jul 01.
Article in English | MEDLINE | ID: mdl-1596042

ABSTRACT

OBJECTIVE: To investigate mitral regurgitation occurring early in the course of acute myocardial infarction with respect to its incidence, the impact of infarct size and location, the accuracy of clinical detection, the contribution of global and regional left ventricular performance, and its influence on prognosis. DESIGN: Prospective observational study derived from patients entering Phase I of the Thrombolysis in Myocardial Infarction (TIMI) trial. SETTING: Multicenter trial involving 13 university-affiliated medical centers. PATIENTS: A total of 206 patients studied within 7 hours of symptom onset during their first myocardial infarction. MEASUREMENTS: Contrast left ventriculography was used to document mitral regurgitation. RESULTS: Mitral regurgitation was present in 27 patients (13%). Although the presence of regurgitation correlated with the site of infarction (20 of 27 had anterior infarctions) and the number of akinetic chords, it was not statistically related to the peak creatine kinase value or to left ventricular chamber size or filling pressure. A murmur of mitral regurgitation was heard in only 2 patients (1 incorrectly). The presence of early mitral regurgitation predicted cardiovascular mortality at 1 year by univariate (relative risk, 12.2; 95% Cl, 3.5 to 42; P less than 0.0001) and multivariate (relative risk, 7.5; Cl, 2.0 to 28.6; P = 0.0008) analyses. CONCLUSIONS: Mitral regurgitation in early myocardial infarction is generally clinically "silent," is more common in anterior infarction, is associated with regional dysfunction but not early ventricular dilation or peak enzyme release, and is an important predictor of cardiovascular mortality.


Subject(s)
Mitral Valve Insufficiency/etiology , Myocardial Infarction/complications , Adult , Aged , Cineradiography , Female , Follow-Up Studies , Heart Auscultation , Heart Ventricles/diagnostic imaging , Humans , Incidence , Male , Middle Aged , Mitral Valve Insufficiency/diagnosis , Mitral Valve Insufficiency/epidemiology , Mitral Valve Insufficiency/mortality , Myocardial Infarction/mortality , Prognosis , Regression Analysis , Survival Rate , Time Factors
19.
Am Heart J ; 123(5): 1273-8, 1992 May.
Article in English | MEDLINE | ID: mdl-1575145

ABSTRACT

Although newer contrast mediums have improved hemodynamic stability during left ventriculography, the image quality and hence the diagnostic yield of the procedure is largely determined by the choice of catheter and injection technique. In this study 125 patients were prospectively assigned at random to undergo ventriculography using either of two pigtail catheters, one with a straight shaft throughout its length (straight) and one with a 145-degree bend placed 6.5 cm from the distal end (angled). Injectate composition, flow rate, and volume were held constant for all injections, and baseline clinical and catheterization variables were found to be similar in each group. The angled catheter exhibited a statistically superior ease of insertion (p = 0.038) and took less time to position (p = 0.012), saving a mean of 23 seconds of fluoroscopy time per procedure. It was also associated with superior contour edge definition (p = 0.037) and a trend toward more uniform distribution of contrast medium (p = 0.089). Compared with the straight catheter, the angled catheter was less frequently accompanied by artifactual mitral regurgitation (p = 0.038) but was equally likely to provoke ventricular arrhythmias during injection. These observed differences may be explained in part by the tendency for angled catheters to more frequently localize in the central as opposed to the inferoposterior region of the left ventricular cavity (mean distance from center = 0.53 vs 1.10 cm, respectively; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Cardiac Catheterization/instrumentation , Gated Blood-Pool Imaging/instrumentation , Aged , Cardiac Catheterization/adverse effects , Cardiac Catheterization/statistics & numerical data , Evaluation Studies as Topic , Female , Humans , Male , Middle Aged , Prospective Studies
20.
Am J Cardiol ; 69(4): 303-7, 1992 Feb 01.
Article in English | MEDLINE | ID: mdl-1734639

ABSTRACT

Multiple lead systems are shown to have a higher sensitivity than that of single leads for detecting coronary artery disease (CAD) during exercise testing, but the value of ST-segment depression isolated to the inferior leads is questionable. To ascertain the diagnostic accuracy of inferior limb lead II compared with that of precordial lead V5, a retrospective analysis of 173 men was performed (108 in a training population and 65 in a validation cohort). All patients had a standard exercise test and underwent diagnostic coronary angiography within 15 days of the exercise test (range 1 to 65). Sixty-three patients had greater than or equal to 1 coronary stenoses greater than or equal to 70%, or left main lesion greater than or equal to 50%, whereas 45 patients in the training population did not. Exclusion criteria were female sex, left ventricular hypertrophy, left bundle branch block or resting ST-segment depression on the baseline electrocardiogram, previous myocardial infarction or revascularization procedures, and any significant valvular or congenital heart disease. Lead V5 had a better combination of sensitivity (65%) and specificity (84%) (chi-square = 24.11; p less than 0.001) than that of lead II (sensitivity 71%, specificity 44%) (chi-square = 2.25; p = 0.13) at a single cut point, and this improved specificity was substantial (95% confidence interval for observed difference 22 to 58%). Receiver-operating characteristic curve analysis also revealed that lead V5 (area = 0.759) was markedly superior to lead II (area = 0.582) over multiple cut points (z = 3.032; 2p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Coronary Disease/diagnosis , Electrocardiography/methods , Exercise Test , Adult , Aged , Analysis of Variance , Chi-Square Distribution , Coronary Disease/physiopathology , Humans , Male , Middle Aged , Predictive Value of Tests , ROC Curve , Retrospective Studies , Signal Processing, Computer-Assisted
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