[Show abstract][Hide abstract]ABSTRACT: We sought to characterize the clinical determinants of mortality in patients with angiographically diagnosed ischemic or nonischemic cardiomyopathy.
Patients with ischemic cardiomyopathy may have a worse prognosis than patients with nonischemic cardiomyopathy. Few studies have assessed the effect of ischemic versus nonischemic etiology on outcomes.
We analyzed prospectively collected data on 3,787 patients with a left ventricular ejection fraction < or = 40% who underwent coronary angiography. Patients were considered to have ischemic cardiomyopathy (n = 3,112) if they had a history of myocardial infarction, percutaneous transluminal coronary angioplasty, coronary artery bypass graft surgery or at least one major epicardial coronary artery with > or = 75% stenosis; all others were considered to have nonischemic cardiomyopathy (n = 675).
The median age, ejection fraction and proportion of patients with New York Heart Association functional class III or IV symptoms for the nonischemic and ischemic groups were 55 years versus 63 years, 27% versus 32% and 57% versus 25%, respectively. After adjustment for baseline clinical risk factors and presenting characteristics, ischemic etiology remained an important independent predictor of 5-year mortality (p < 0.0001). The extent of coronary artery disease was a better predictor of survival than ischemic or nonischemic etiology (log likelihood chi-square 700 vs. 675, respectively).
Ischemic etiology is a significant independent predictor of mortality in patients with cardiomyopathy. However, the extent of coronary artery disease contributes more prognostic information than the clinical diagnosis of ischemic or nonischemic cardiomyopathy. Further research is needed to refine the clinical definition of ischemic cardiomyopathy so that physicians can appropriately prescribe treatment and accurately predict outcome.
Full-text Article · Oct 1997 · Journal of the American College of Cardiology
[Show abstract][Hide abstract]ABSTRACT: In order to limit costs, health care organizations in the United States are shifting medical care from specialists to primary care physicians. Although primary care physicians provide less resource-intensive care, there is little information concerning the effects of this strategy on outcomes.
We examined mortality according to the specialty of the admitting physician among 8241 Medicare patients who were hospitalized for acute myocardial infarction in four states during a seven-month period in 1992. Proportional-hazards regression models were used to examine survival up to one year after the myocardial infarction. To determine the generalizability of our findings, we also examined insurance claims and survival data for all 220,535 patients for whom there were Medicare claims for hospital care for acute myocardial infarction in 1992.
After adjustment for characteristics of the patients and hospitals, patients who were admitted to the hospital by a cardiologist were 12 percent less likely to die within one year than those admitted by a primary care physician (P<0.001). Cardiologists also had the highest rate of use of cardiac procedures and medications, including medications (such as thrombolytic agents and beta-blockers) that are associated with improved survival.
Health care strategies that shift the care of elderly patients with myocardial infarction from cardiologists to primary care physicians lower rates of use of resources (and potentially lower costs), but they may also cause decreased survival. Additional information is needed to elucidate how primary care physicians and specialists should interact in the care of severely ill patients.
Article · Dec 1996 · New England Journal of Medicine
[Show abstract][Hide abstract]ABSTRACT: Digital coronary angiographic techniques are now widely used in many cardiac catheterization laboratories. However, the full potential of digital imaging technology remains to be achieved because of its enormous storage and exchange requirements. Compression of digital imaging data allows a reduction in the volume of data so that storage and transmission are more efficient and cost-effective. Three angiographers reviewed the original and compressed formats of 96 coronary angiographic sequences in a blinded fashion to assess coronary lesion severity. Compression was achieved using the Joint Photographic Experts Group (JPEG) standard, which resulted in a compression ratio of approximately 15:1. The original format was reviewed in a blinded fashion a second time to assess for intraobserver variability of similar formats. Lesion severity was graded in quartiles. Coronary stenosis >50% was considered "significant." In parallel, the reproducibility of quantitative coronary angiographic (QCA) measurements of coronary artery dimensions was also evaluated. For the visual assessment of lesion severity in the compressed versus original formats, kappa=0.52, suggesting moderate agreement. When lesions were assessed as significant versus "insignificant," however, kappa=0.88, suggesting excellent agreement. In the 2 separate readings of the original data formats, kappa=0.44 for assessment of lesion severity by quartiles and kappa=0.72 for lesions assessed as significant versus insignificant. Analysis of the compressed versus original data sets using QCA resulted in an excellent correlation for the measurement of lesion severity (r=0.99). The correlation was equally strong when the original format was analyzed sequentially (r=0.98). Lossy JPEG (15:1) compression is a valid means for reducing storage and exchange requirements of coronary angiographic data. The variability in assessing lesion severity between the original and compressed formats is comparable to the reported variability in visual assessment of lesion severity in sequential analysis of cine film.
Article · Aug 1996 · The American Journal of Cardiology
[Show abstract][Hide abstract]ABSTRACT: This editorial comment provides a perspective on the changing nature of the health care system acid the need for cardiovascular databases to play a critical role in objective determination of therapeutic strategies for patients.
Article · Jan 1996 · The American Journal of Cardiology
[Show abstract][Hide abstract]ABSTRACT: Concerns about increasing costs of health care combined with an increasing appreciation of the variability in health care delivery practices has led to the development of strategies to better standardise health care delivery. Care-plans and practice algorithms define road maps of care and decision algorithms for individual patient conditions. When incorporated into routine clinical practice and coupled with the recording of the outcomes of care, they permit an improved understanding of how to provide more cost-effective health care. Routine integration into information systems should help to establish a continuous quality improvement model for health care delivery. Substantial problems exist, however, in the development of care-plans and integrating them into information systems and routine clinical practice.
Article · May 1995 · International Journal of Bio-Medical Computing
[Show abstract][Hide abstract]ABSTRACT: Health care payors and consumers have a growing interest in risk-adjusted provider profiles. Using chart-abstracted clinical data from the Cooperative Cardiovascular Project, we ranked 28 hospitals performing bypass surgery in Alabama and Iowa by their risk-adjusted surgical mortality rates using three published risk-adjustment methodologies: Parsonnet (PI, O’Connor (a) and Hannan (H). In total. 3653 bypass surgery cases performed from 6/92 to 3/93 were reviewed (mean 130 cases/hospital). The discriminatory abilities of each method for predicting surgical mortality were quite similar (area under ROC curves 0.72–0.75). Below, we display the risk-adjusted hospital rankings (comparing observed with expected mortality) by these three riskadjustment techniques:View thumbnail imagesView high quality image (87K)In terms of hospital rankings, there was generally close correlation between any two of the methods (Spearman's R = 0.87,0.88, and 0.93, comparing P-O, P-H, and H-O). Rankings for an individual hospital varied, however, an average of ± 3.3 ranks (range 0–12 ranks) depending on which riskadjustment methodology was used.Conclusion
In general. published methods of risk-adjustment for bypass surgery accurately identify institutions with low, moderate and high adjusted mortality outcomes. The precise ranking of an individual hospital. however, may vary depending on the risk adjustment method applied.
Article · Feb 1995 · Journal of the American College of Cardiology
[Show abstract][Hide abstract]ABSTRACT: We proposed to examine the relation between angiographic morphologic characteristics and abrupt closure after coronary angioplasty and to develop an empirically based risk stratification system.
Certain lesion morphologic characteristics are associated with higher rates of abrupt closure after coronary angioplasty. Previous approaches have been limited by relatively small sample sizes and an inability to combine multiple characteristics to predict risk in an individual patient.
Lesion morphology was determined for 779 lesions in 658 patients undergoing an elective first angioplasty. Abrupt closure occurred in 63 lesions (8.1%). Variables associated with abrupt closure were identified by univariate and stepwise multiple logistic regression analysis, and internal validity was assessed by use of bootstrapping. An empirically based scoring system was developed by assigning different weights to each predictive characteristic and was then validated.
Almost all lesion characteristics previously labeled "adverse" were associated with an increased risk of abrupt closure, but only total occlusion, location at a branch point, increasing lesion length, evidence for thrombus and right coronary artery location were statistically significant independent predictors. Despite the large sample size, the study was underpowered to detect even a 50% increase in risk with many characteristics. Using a scoring system, we assigned each lesion a specific risk of abrupt closure. The distribution of risk was broad, with 20% of patients having < or = 2.5% risk and 25% having > 10% risk. Internal validation techniques revealed that when 10% of patients were randomly eliminated from the sample in multiple iterations, the risk estimates varied, again pointing to the need for a larger sample.
Empirically based weighting of lesion characteristics could quantify the risk of abrupt closure for individual patients, but a very large sample will be required to understand the interplay of complex lesion characteristics in altering expected outcomes.
Article · Oct 1994 · Journal of the American College of Cardiology
[Show abstract][Hide abstract]ABSTRACT: The clinical application of quantitative methods for coronary arteriography remains limited, due in large part to the absence of a suitable replacement for cinefilm as the procedure record. The extension to the clinical environment of the validated objective methods which have found such widespread acceptance in clinical research studies is difficult to implement if the time-consuming and variable process for digitization of selected cinefilm frames is required. In addition, the complete integration of the angiographic procedure record with other patient records and procedures stored in a digital data format requires that the angiographic data eventually be converted to a digital format as well. Replacement of cinefilm requires that the media chosen for the task provide at least the same capabilities and preferably improved functions as those provided by cinefilm as a display, transport, and archival media. The demanding set of requirements imposed on the replacement options include high capacity, high acquisition rate, high transfer rate, application in a distributed environment, portability between institutions, and low expense. A true digital solution should also provide immediate access to the results of the angiographic procedure, transfer of image data over digital networks, multiple-user viewing capability, and quantitative analysis on a routine basis for all patients. In fact, a single media may not provide all the capabilities listed above but, rather, different media may need to be used for specialized tasks, i.e. the solution for archival may not be the same that will be employed as the portable patient record. Separation of the archival function from the acquisition/display and portable transfer functions increases the likelihood that cinefilm can be replaced in the imminent future by reducing the demands on a single media. Among the archival options available today are: (1) magnetic disks; (2) analog laser optical disks; (3) digital laser optical disks; (4) digital file-based magnetic tape; (5) digital video magnetic tape. In evaluating each of these alternatives, an accounting is required of how each meets the archival requirements along with an approximate breakdown of cost and readiness for implementation as a clinical solution today.
Article · Oct 1994 · International Journal of Cardiac Imaging
[Show abstract][Hide abstract]ABSTRACT: Survival after coronary artery bypass graft surgery (CABG) and medical therapy in patients with coronary artery disease (CAD) has been studied in both randomized trials and observational treatment comparisons. Over the past decade, the use of coronary angioplasty (PTCA) has increased dramatically, without guidance from either randomized trials or prospective observational comparisons. The purpose of this study was to describe the survival experience of a large prospective cohort of CAD patients treated with medicine, PTCA, or CABG.
The study was designed as a prospective nonrandomized treatment comparison in the setting of an academic medical center (tertiary care). Subjects were 9263 patients with symptomatic CAD referred for cardiac catheterization (1984 through 1990). Patients with prior PTCA or CABG, valvular or congenital disease, nonischemic cardiomyopathy, or significant (> or = 75%) left main disease were excluded. Baseline clinical, laboratory, and catheterization data were collected prospectively in the Duke Cardiovascular Disease Databank. All patients were contacted at 6 months, 1 year, and annually thereafter (follow-up 97% complete). Cardiovascular death was the primary end point. Of this cohort, 2788 patients were treated with PTCA (2626 within 60 days) and 3422 with CABG (3080 within 60 days). Repeat or crossover revascularization procedures were counted as part of the initial treatment strategy. Kaplan-Meier survival curves (both unadjusted and adjusted for all known imbalances in baseline prognostic factors) were used to examine absolute survival differences, and treatment pair hazard ratios from the Cox model were used to summarize average relative survival benefits. For the latter, a 13-level CAD prognostic index was used to examine the relation between survival and revascularization as a function of CAD severity. The effects of revascularization on survival depended on the extent of CAD. For the least severe forms of CAD (ie, one-vessel disease), there were no survival advantages out to 5 years for revascularization over medical therapy. For intermediate levels of CAD (ie, two-vessel disease), revascularization was associated with higher survival rates than medical therapy. For less severe forms of two-vessel disease, PTCA had a small advantage over CABG, whereas for the most severe form of two-vessel disease (with a critical lesion of the proximal left anterior descending artery), CABG was superior. For the most severe forms of CAD (ie, three-vessel disease), CABG provided a consistent survival advantage over medicine. PTCA appeared prognostically equivalent to medicine in these patients, but the number of PTCA patients in this subgroup was low.
In this first large-scale, prospective observational treatment comparison of PTCA, CABG, and medicine, we confirmed the previously reported survival advantages for CABG over medical therapy for three-vessel disease and severe two-vessel disease. For less severe CAD, the primary treatment choices are between medicine and PTCA. In these patients, there is a trend for a relative survival advantage with PTCA, although absolute survival differences were modest. In this setting, treatment decisions should be based not only on survival differences but also on symptom relief, quality of life outcomes, and patient preferences.
[Show abstract][Hide abstract]ABSTRACT: Abrupt closure after coronary angioplasty is often successfully treated by repeat dilation. Long-term follow-up, including 6-month repeat catheterization and 12-month clinical evaluation, was obtained in 1,056 patients treated with acute (n = 335) or elective (n = 721) coronary angioplasty to evaluate the long-term impact of successful reopening of abrupt closure. Abrupt closure occurred in 13.5% of patients and was successfully reopened in 58%. Adverse outcomes including restenosis, death, bypass surgery, myocardial infarction and repeat angioplasty were compared between patients with successfully treated abrupt closure and those with successful procedures (residual diameter stenosis < or = 50%) without abrupt closure. For patients with acute angioplasty, the restenosis rates (> 50% diameter stenosis at follow-up) were 64% for those with successfully treated abrupt closure versus 36% for those with successful procedures without abrupt closure (p < 0.01). In addition, subsequent myocardial infarction (12 vs 3%; p = 0.01) and repeat angioplasty (21 vs 10%; p = 0.03) were more frequent in the group with abrupt closure. For patients with elective angioplasty, restenosis was 43% in those with successfully treated abrupt closure versus 45% in those without abrupt closure (p = NS). Subsequent death and myocardial infarction were more frequent in patients with abrupt closure (death: 12 vs 3% [p < 0.01]; myocardial infarction: 13 vs 3% [p < 0.01]). Long-term adverse events are increased in patients with successfully treated abrupt closure compared to those with successful procedures without abrupt closure.
Article · Aug 1993 · The American Journal of Cardiology
[Show abstract][Hide abstract]ABSTRACT: Balloon angioplasty of long coronary artery narrowings has been associated with a lower rate of acute success, and a higher rate of acute complications and restenosis than that observed for short narrowings. Angioplasty catheters with longer length balloons (30 and 40 mm) are now available, and the objective of this study was to determine the acute and long-term success for patients with long coronary artery narrowings treated with these longer balloons. All patients with long narrowings (> or = 10 mm) treated with long balloons at 1 institution over a 1-year period were identified (93 narrowings in 89 patients), and acute and long-term outcomes were carefully documented. Procedural success (residual stenosis < or = 50%) was 97%. Abrupt closure occurred in 6% and major dissection in 11% of narrowings. Clinical success (procedural success without in-hospital death, bypass surgery or myocardial infarction) was achieved in 90% of patients. Repeat catheterization was performed in 61 patients (76% of those eligible), and restenosis was found in 50 to 55%, depending on the definition used. The treatment of long coronary artery narrowings using angioplasty catheters with longer balloons leads to high rates of acute success. However, there is a high rate of restenosis. New interventional devices for long lesions should be compared with long balloons in a randomized controlled trial.
Article · Jun 1993 · The American Journal of Cardiology
[Show abstract][Hide abstract]ABSTRACT: Despite a seemingly exponential rise in the number of coronary angioplasty procedures since the introduction of the procedure in 1977, several major limitations to more widespread use still remain. These include difficulty traversing chronic total occlusions, the development of major dissection with an attendant increase in the risk of abrupt closure and the continuing problem of restenosis in a significant minority of patients. This has resulted in the development of a number of new technologies to address some facet of each of the above limitations. One promising new device is the Transluminal Extraction-endarterectomy Catheter (TEC). The device is introduced percutaneously and consists of a flexible torque tube that tracks over a flexible guidewire under standard fluoroscopic guidance. A unique feature of the TEC is the simultaneous application of suction while the conical cutter rotates and removes atheromatous plaque. This reservoir allows for the collection of the excised fragments for later analysis.
Preliminary data suggest that while the TEC can be used for lesions able to be treated with conventional balloon angioplasty devices, it may have special utility in two situations that are not particularly well suited for balloon angioplasty — long diffuse disease and bypass grafts. As a result of the need to compare this new technology to established devices, the TEC Multicenter Registry was formed with the goal of enrolling 317 patients. Core lab evaluation includes determination of absolute dimensions, i.e. lesion length, minimal lumen diameter and average reference diameter as well as conventional parameters such as percent diameter and area stenosis. A particular emphasis of our laboratory has been on the methodology for calibration of images in order to calculate absolute dimensions, as well as determining the role of lesion morphology in choosing new devices. The TEC is a promising new technology which may have special utility in treating long, diffuse disease and bypass grafts, further expanding the realm of interventional cardiology.
[Show abstract][Hide abstract]ABSTRACT: The authors developed a flexible and powerful coronary anatomy
classification system which can be applied to the development and
evaluation of qualitative and quantitative methods for assessing
myocardium in jeopardy on the basis of the severity and location of
coronary artery lesions, relative size of arteries, and contributions
from collateral blood flow. The system employs a graphical user
interface for the interactive generation of a coronary tree diagram
depicting a patient's coronary anatomy. An anatomical relational
database for over 5000 patients has been collected. Various
classification schemes can be rapidly applied to this data set and
iteratively modified to arrive at a model which correlates best with
patient prognosis. As an example of this system's ability to easily
implement complex coronary artery disease risk classification models, a
risk region analysis model based on size and distribution of terminating
vessels was implemented. This method offers a significant improvement
over its predecessors in that it takes into account changes in coronary
size and distribution among different patients
[Show abstract][Hide abstract]ABSTRACT: An expert panel task force of the AHA/ACC reported that
determination of lesion morphology was predictive of adverse events
after diagnostic/interventional procedures. The authors have developed a
coronary artery tree diagramming system that employs a graphical user
interface to allow rapid and facile data entry by clinical personnel. In
addition to the baseline anatomic descriptors of coronary artery
anatomy, lesion morphology descriptors comprising each data element
comprising the AHA/ACC class are easily entered. Average time for data
entry per tree is 2 min. The system is used on a daily basis at Duke
University Medical Center for recording the results of the 20-25
diagnostic and 10-15 interventional procedures. The recording of complex
lesion morphology data can now be easily performed as part of routine
clinical care in large clinical populations undergoing catheterization