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Biomedical subjects

R J Krone

Publications and source records attributed to R J Krone.

At least 19 recordsLinked to original sources
PubMed2001

The effects of contemporary use of coronary stents on in-hospital mortality. Registry Committee of the Society for Cardiac Angiography and Interventions.

OBJECTIVES: This study was designed to determine the effect of coronary stents on in-hospital mortality. BACKGROUND: Despite extensive use of stents for percutaneous coronary interventions (PCIs), their effect on serious in-hospital events, especially mortality, is not well defined. METHODS: A cohort study was performed using 16,811 consecutive native-vessel PCI procedures performed on patients in the Society for Cardiac Angiography & Interventions Registry from July 1, 1996, through December 31, 1998. Patients undergoing balloon-only angioplasty were compared with those receiving a planned or unplanned stent. Procedures with other devices were excluded. Multivariable analyses adjusted for detailed clinical characteristics and for individual laboratory. RESULTS: Stents were associated with a significant reduction in in-hospital mortality (0.3%) compared with balloon procedures (0.6%; multivariable odds ratio [OR] 0.55; 95% confidence interval [CI] 0.34, 0.89; p = 0.014). The risk of emergency coronary bypass also was reduced by stenting (0.3% vs. 0.7%; multivariable OR 0.47; 95% CI: 0.29, 0.76; p = 0.002). Adjustment for the use of glycoprotein IIb/IIIa inhibitors did not change the results, and the effects of stenting relative to balloon procedures were similar in those procedures with and without glycoprotein IIb/IIIa blockade (p = 0.94). CONCLUSIONS: This study suggests that coronary stenting, compared with balloon procedures, reduces in-hospital mortality, independent of the clinical setting.

Adult↗
PubMed2001

Risk stratification after successful coronary revascularization: the lack of a role for routine exercise testing.

OBJECTIVE: The objective of this study was to evaluate the American College of Cardiology/American Heart Association (ACC/AHA) guidelines for exercise testing (EXT) after successful coronary revascularization (CR) using the Bypass Angioplasty Revascularization Investigation experience. BACKGROUND: The ACC/AHA guidelines state that EXT within three years of successful CR is not useful. METHODS: The 1,678 patients randomized to CR by either angioplasty or bypass surgery were required to take symptom-limited treadmill tests one, three and five years after revascularization. RESULTS: Patients who took the test at each specified time had a much lower subsequent two-year mortality than those who did not (1.9% vs. 9.4%, 3.5% vs. 12.6% and 3.3% vs. 11.0% at one, three and five years, respectively, after CR [p < 0.0001 for each]). Exercise parameters at the one- and three-year test did not improve a multivariable model of survival after including clinical parameters. Exercising to Bruce stage 3 or generating a Duke score >-6 were independently predictive of two-year survival after the five-year test. ST depression on the one-year test was associated with more revascularizations (relative risk = 1.6; p < 0.001). CONCLUSIONS: Patients with stable multivessel coronary disease who took a protocol-mandated exercise test at one, three and five years after revascularization were at low risk for mortality in the two years subsequent to each test. Exercise parameters did not improve prediction of mortality in the two years after the one- and three-year tests. The ACC/AHA guidelines on exercise testing after CR (no value for routine testing in stable patients for three years after revascularization) are supported by these results.

Angioplasty, Balloon, Coronary↗
PubMed2000

Effect of smoking on lipid and thrombogenic factors two months after acute myocardial infarction.

Cigarette smoking is linked to increased cardiac morbidity and mortality, and has been shown to affect both lipid profiles and thrombotic factors in healthy subjects. However, the influence of smoking on the atherothrombotic environment has not been studied in a large population of patients after acute myocardial infarction (AMI). Blood samples and medical history, including smoking status, were obtained from 1,045 patients at a 2-month visit after AMI. Smokers were asked to refrain 24 hours before the visit, but not all complied. Measurements included total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, apolipoprotein-B, apolipoprotein-A, triglycerides, factor VII, factor VIIa, von Willebrand factor, D-dimer, and plasminogen activator inhibitor. There were 247 current, 443 past, and 349 nonsmokers. After adjustment for clinical variables, current smokers had higher levels of total cholesterol and apolipoprotein-B than past and nonsmokers (p <0.01). High-density lipoprotein cholesterol and apolipoprotein-A levels were similar between groups. Fibrinogen was elevated in current (p = 0.001) and past (p = 0.029) smokers, compared with nonsmokers. Smokers who smoked within 24 hours of blood sampling had higher apolipoprotein-B (p = 0.005), total cholesterol (p = 0.001), and fibrinogen (p = 0.015) levels than those who refrained from smoking. In conclusion, postinfarction patients, who historically have higher levels of atherogenic lipids than healthy subjects, have increased levels of these lipids attributed to active smoking. After smoking cessation, lipid profiles approach nonsmoker levels, but fibrinogen remains elevated. Smoking within 24 hours of blood sampling was associated with further adverse prothrombotic and lipogenic effects.

Aged↗
PubMed2000

A simplified lesion classification for predicting success and complications of coronary angioplasty. Registry Committee of the Society for Cardiac Angiography and Intervention.

In 1988, the American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures presented a classification of coronary lesions utilizing 26 lesion features to predict the success and complications of balloon angioplasty. Using data from the Registry of the Society for Cardiac Angiography and Interventions (SCAI) we evaluated the ability of this classification to predict success and complications. Lesion success, death in hospital, emergency cardiac bypass surgery, and major adverse events were evaluated in 41,071 patients who underwent single-vessel angioplasty from January 1993 to June 1996. Logistic models using the ACC/AHA lesion classification, vessel patency, or both, were compared. A new classification based on the interaction of the ACC/AHA classification plus lesion patency was compared with the existing ACC/AHA classification. Vessel patency, added to the ACC/AHA classification, improved prediction of lesion success (p </=0.0001). Class A and patent B lesions had similar success and complication rates, so a simplified classification (SCAI) using only 7 lesion characteristics could be created. This system (I: non-C patent, II: C patent, III: non-C occluded, and IV: C occluded) improved prediction of lesion success compared with the ACC/AHA classification (Bayesian Information Criterion statistic: ACC/AHA 16539, SCAI 15956; and area under the receiver- operating characteristics curve 0.659, 0.693, respectively). The SCAI classification was preferred for predicting major complications and in-hospital death and was similar to the ACC/AHA classification for predicting emergency bypass surgery.

Aged↗
PubMed2000

Contemporary trends in coronary intervention: a report from the Registry of the Society for Cardiac Angiography and Interventions.

This report of the Registry for the Society for Cardiac Angiography and Interventions provides data on the trends in coronary interventional procedures from the time period June 1966 through December 1998. A total of 19,510 consecutive coronary interventional procedures were recorded. Over this time period, significant trends in coronary stent implantation were recorded along with a decreasing reliance on balloon angioplasty as sole therapy. Patients with acute myocardial infarction comprised an increased fraction of all procedures. Almost half of all interventions were performed in patients with multivessel disease. Finally, decreasing rates of in-hospital death and emergent bypass surgery compared to prior reports from the registry characterize the current practice of interventional cardiology. Cathet. Cardiovasc. Intervent. 49:19-22, 2000.

Aged↗
PubMed1999

Thrombogenic factors and recurrent coronary events.

BACKGROUND: Thrombosis is a pivotal event in the pathogenesis of coronary disease. We hypothesized that the presence of blood factors that reflect enhanced thrombogenic activity would be associated with an increased risk of recurrent coronary events during long-term follow-up of patients who have recovered from myocardial infarction. METHODS AND RESULTS: We prospectively enrolled 1045 patients 2 months after an index myocardial infarction. Baseline thrombogenic blood tests included 6 hemostatic variables (D-dimer, fibrinogen, factor VII, factor VIIa, von Willebrand factor, and plasminogen activator inhibitor-1), 7 lipid factors [cholesterol, triglycerides, HDL cholesterol, LDL cholesterol, lipoprotein(a), apolipoprotein (apo)A-I, and apoB], and insulin. Patients were followed up for an average of 26 months, with the primary end point being coronary death or nonfatal myocardial infarction, whichever occurred first. The hemostatic, lipid, and insulin parameters were dichotomized into their top and the lower 3 risk quartiles and evaluated for entry into a Cox survivorship model. High levels of D-dimer (hazard ratio, 2.43; 95% CI, 1.49, 3.97) and apoB (hazard ratio, 1.82; 95% CI, 1.10, 3.00) and low levels of apoA-I (hazard ratio, 1.84; 95% CI, 1.10, 3.08) were independently associated with recurrent coronary events in the Cox model after adjustment for 6 relevant clinical covariates. CONCLUSIONS: Our findings indicate that a procoagulant state, as reflected in elevated levels of D-dimer, and disordered lipid transport, as indicated by low apoA-1 and high apoB levels, contribute independently to recurrent coronary events in postinfarction patients.

Adult↗
PubMed1999

Coronary revascularization in diabetic patients: a comparison of the randomized and observational components of the Aypass Angioplasty Revascularization Investigation (BARI).

BACKGROUND: Patients with treated diabetes in the randomized-trial segment of the Bypass Angioplasty Revascularization Investigation (BARI) who were randomized to initial revascularization with PTCA had significantly worse 5-year survival than patients assigned to CABG. This treatment difference was not seen among diabetic patients eligible for BARI who opted to select their mode of revascularization. We hypothesized that differences in patient characteristics, assessed and unmeasured, together with the treatment selection in the registry, at least partially account for this discrepancy. METHODS AND RESULTS: Among diabetics taking insulin or oral hypoglycemic drugs at entry, angiographic and clinical presentations were comparable between randomized and registry patients. However, more registry patients were white, and registry diabetics tended to be more educated and more physically active and to report better quality of life. Procedural characteristics and in-hospital complications were comparable. The 5-year all-cause mortality rate was 34.5% in randomized diabetic patients assigned to PTCA versus 19.4% in CABG patients (P=0.0024; relative risk [RR]=1.87); corresponding cardiac mortality rates were 23.4% and 8.2%, respectively (P=0.0002; RR=3.10). The CABG benefit was more apparent among patients requiring insulin. In the registry, all-cause mortality was 14.4% for PTCA versus 14.9% for CABG (P=0.86, RR=1.10), with corresponding cardiac mortality rates of 7.5% and 6. 0%, respectively (P=0.73; RR=1.07). These RRs in the registry increased to 1.29 and 1.41, respectively, after adjustment for all known differences between treatment groups. CONCLUSIONS: BARI registry results are not inconsistent with the finding in the randomized trial that initial CABG is associated with better long-term survival than PTCA in treated diabetic patients with multivessel coronary disease suitable for either surgical or catheter-based revascularization.

Aged↗
PubMed1998

Importance of exercise capacity in the interpretation of a myocardial ischemic response to exercise testing. Multicenter Study of Myocardial Ischemia Group (MSMI).

Patients who were stable 1 to 6 months after a cardiac event underwent routine exercise testing with thallium scintigraphy. The prognosis of patients with good exercise capacity (Bruce stage 3) was similar whether or not ischemia was demonstrated and similar to patients with reduced exercise capacity and no ischemia, whereas the presence of both ischemia and a reduced exercise tolerance identified patients with a significantly poorer prognosis.

Aged↗
PubMed1998

Diagnosis and prognosis of silent ischemia.

Patients with coronary disease react differently to ischemia. Some (types I and II) experience no symptoms, while most patients with silent ischemia have both symptomatic and asymptomatic ischemia. The best evidence suggests that prognosis is determined by the amount of ischemia, not its presentation. In addition, in these patients, silent ischemia during daily living is not common. Prospective prognostic studies have not been performed in patients who do not experience angina with ischemia, therefore treatment must be individualized in these patients, considering the lack of a "warning system".

Angina Pectoris↗
PubMed1997

Predictors of success and major complications for primary percutaneous transluminal coronary angioplasty in acute myocardial infarction. An analysis of the 1990 to 1994 Society for Cardiac Angiography and Interventions registries.

OBJECTIVES: The purpose of this study was to determine predictors of successful coronary angioplasty for acute myocardial infarction (MI) and associated predictors of the major complications of in-hospital mortality and emergency coronary artery bypass graft surgery. BACKGROUND: Primary angioplasty is being increasingly used to treat acute MI, but factors affecting the success and major complications have not been well studied. Forty laboratories have been contributing clinical and procedural data to the Society of Cardiac Angiography and Interventions (SCA&I) on primary angioplasty for acute MI. METHODS: Univariable and stepwise multivariable logistic regression analysis of clinical and procedural variables was used to calculate predictors of success and major complications. RESULTS: There were 4,366 primary angioplasty procedures reported from 1990 through 1994, with an overall success rate of 91.5%, an in-hospital mortality rate of 2.5% and a rate of emergency surgery of 4.3%. Higher laboratory primary angioplasty volume and lower age were predictive of success. An intraaortic balloon pump in place, cardiogenic shock and a moribund condition had negative predictive effects. Unsuccessful angioplasty, cardiogenic shock or a moribund state were predictive of in-hospital death. Unsuccessful angioplasty, the absence of a history of hypertension and the absence of congestive heart failure were predictive of emergency surgery. CONCLUSIONS: The rates of success and major complications in the SCA&I Registry are similar to other series. Predictors of success and major complications can be assessed and may be useful for risk stratifying candidates for primary angioplasty in acute MI.

Aged↗
PubMed1997

Risk of major complications from coronary angioplasty performed immediately after diagnostic coronary angiography: results from the Registry of the Society for Cardiac Angiography and Interventions.

OBJECTIVES: This study was designed to determine the risk of performing percutaneous transluminal coronary angioplasty (PTCA) at the time of diagnostic catheterization ("combined procedures"). BACKGROUND: Health care providers are under increasing pressure to combine diagnostic and interventional coronary procedures to reduce costs. However, the risk associated with combined procedures has not been rigorously assessed. METHODS: A multicenter cohort study of 35,700 patients undergoing elective PTCA from 1992 through 1995 was performed to determine the risk of major complications (myocardial infarction, emergency coronary artery bypass graft surgery or death) from combined relative to staged procedures (i.e., performing PTCA at a session subsequent to diagnostic catheterization). RESULTS: The risks of major complications from combined and staged procedures were 2.0% and 1.6%, respectively (unadjusted odds ratio [OR] 1.28, 95% confidence interval [CI] 1.05 to 1.57). After adjusting for clinical and angiographic differences and clustering by laboratory, the risk from combined procedures was not significantly elevated (multivariable OR 1.18, 95% CI 0.89 to 1.55). However, several subgroups of patients did have an increased risk from combined procedures: patients with multivessel disease (multivariable OR 1.64, 95% CI 1.13 to 2.39); women (multivariable OR 1.64, 95% CI 1.05 to 2.55); patients > 65 years old (multivariable OR 1.40, 5% CI 1.02 to 1.93); and patients undergoing multilesion PTCA (multivariable OR 1.53, 95% CI 1.06 to 2.21). The risk of combined relative to staged procedures decreased over the 4-year period (multivariable p = 0.029). CONCLUSIONS: Combining PTCA with diagnostic catheterization appears to be safe in many patients. However, several subgroups of patients may be at increased risk. Careful patient selection will most likely remain critical to ensuring the safety of combined procedures.

Aged↗
PubMed1997

Angina pectoris after recovery from an acute coronary event--the role of psychological factors in Japanese vs North American patients.

To determine whether specific psychological characteristics are associated with angina pectoris in clinically stable patients 1 to 6 months after recovery from an acute coronary event, a battery of tests was administered to 92 Japanese and 646 North American participants (22% females) in the Multicenter Study of Myocardial Ischemia. Of these 738 patients, 541 had originally suffered acute myocardial infarction, 188 had unstable angina, and 9 were admitted for other acute ischemic events. At the time of enrollment, an average of 2.7 months after the index event, 205 patients reported having had anginal symptoms during the preceding months. Compared to those who did not report angina, these patients scored higher on a modified Autonomic Perception Questionnaire (p = 0.04) and lower on the Internal Health Locus of Control Scale (p = 0.004). These differences were generalized across the Japanese and North American cohorts. These results indicate that in these patients, angina pectoris was associated with an increased awareness of a wide range of physical symptoms and a decreased sense of personal control over one's own health and prognosis.

Acute Disease↗
PubMed1996

Psychological determinants of anginal pain perception during exercise testing of stable patients after recovery from acute myocardial infarction or unstable angina pectoris.

The objective of this study was to test the hypothesis that psychological factors are determinants of anginal symptoms during positive exercise tests. The sample consisted of clinically stable patients who were enrolled in the Multicenter Study of Myocardial Ischemia 1 to 6 months after admission to a coronary care unit. Among 186 post-myocardial infarction patients, 151 developed ischemia (i.e., a stress-induced myocardial perfusion defect) without symptoms (silent ischemia) and 35 developed angina with ischemia (symptomatic ischemia) during a thallium exercise test; among 39 patients who had been hospitalized for unstable angina, 24 developed silent ischemia and 15 developed symptomatic ischemia. Two sets of psychometric tests were administered: set 1, factors that influence awareness of physical symptoms, and set 2, factors associated with biases toward or against reporting perceived symptoms. Two hundred eleven patients produced complete data in each set. Analysis of set 1 factor scores revealed significant effects of symptom status (p = 0.006) and index event (p = 0.02), but no interaction. No effects were found in set 2. Patients who are clinically stable after recovery from an acute coronary event and who experience angina during exercise testing are more aware of physical symptoms in general than are comparable patients with silent ischemia. Psychological biases toward or against reporting perceived symptoms do not differentiate these groups. Thus, it appears that silent ischemia is probably "silent" in the sense of being truly asymptomatic rather than of stoic endurance or denial of perceived symptoms.

Aged↗
PubMed1996

Five year trends in cardiac catheterization: a report from the Registry of the Society for Cardiac Angiography and Interventions.

The Society for Cardiac Angiography and Interventions has maintained a registry of cardiac catheterizations since 1979 and of percutaneous cardiac interventions since 1990. Data from 392,923 procedures (317,592 diagnostic catheterizations, 74,963 coronary interventions, and 368 valvuloplasties) for the years 1990-1994 inclusive are presented. Over the 5 year period there was a trend toward same day and 23 hr discharges (19% in 1990 to 29% in 1994), and a decrease in combined right and left heart procedures from 38% to 26%. For cardiac catheterizations ionic contrast use declined from 26% of procedures to 13% in 1994. The use of ionic contrast was even lower in interventional procedures, with laboratories reporting use in 21% of procedures in 1990 dropping to 9% in 1994. Balloons were the first choice device in 92.5% of native arteries and 82.7% of grafts in 1994. For the first time in 1994 more mitral than aortic valvuloplasties were reported.

Angioplasty, Balloon, Coronary↗
PubMed1995

Bypass Angioplasty Revascularization Investigation: patient screening, selection, and recruitment.

Percutaneous transluminal coronary angioplasty (PTCA) is currently performed in many patients seeking care because of severe manifestations of multivessel coronary artery disease. Previously, the majority of such patients would have undergone coronary artery bypass grafting (CABG). No definitive evidence is available as to which initial revascularization strategy has the best long-term clinical and economic outcomes. The Bypass Angioplasty Revascularization Investigation (BARI) is the largest of several recent clinical trials that were designed to test the hypothesis that an initial strategy of PTCA in selected patients with multivessel coronary artery disease does not compromise long-term clinical outcome compared with an initial strategy of CABG. This report describes how patients were screened, selected, and recruited in BARI and how this process may influence the results and the interpretation of the trial. During the enrollment period, 25,200 patients undergoing diagnostic coronary angiography at the participating institutions or with off-site angiograms referred to BARI investigators were screened for BARI eligibility. Excluded from screening were patients without coronary artery disease, those with single-vessel disease, prior revascularization, primary congenital, valvular, or myocardial disease, and age > 80 years. Slightly more than half of the patients screened (12,670) were not clinically eligible for BARI because of left main disease, insufficient symptoms, emergency revascularization, or other logistic reasons. Thus, 12,530 patients had severe angina and/or ischemia and were clinically eligible for BARI. Nearly 33% of them (4,110) had multivessel disease, which was suitable for both PTCA and CABG.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

Limited usefulness of exercise testing and thallium scintigraphy in evaluation of ambulatory patients several months after recovery from an acute coronary event: implications for management of stable coronary heart disease. Multicenter Myocardial Ischemia Research Group.

OBJECTIVES: This study evaluated the value of noninvasive testing to predict cardiac events in patients with stable coronary disease after hospital admission (and risk stratification) for an acute coronary event. BACKGROUND: Exercise testing with thallium perfusion imaging identifies patients with obstructive coronary artery disease and has been used to stratify patients after myocardial infarction. Its usefulness for predicting cardiac events in patients with stable coronary disease after recovery from an acute coronary event was explored. METHODS: Nine hundred thirty-six patients were enrolled 1 to 6 months after hospital admission for a coronary event. Patients underwent exercise treadmill testing with planar thallium-201 scintigraphy and were followed up for an average of 23 months (range 6 to 43). End points were 1) unstable angina requiring hospital admission, nonfatal myocardial infarction or cardiac death; 2) nonfatal infarction or cardiac death; or 3) cardiac death alone. RESULTS: Twelve patients died of cardiac causes (1.2%); 32 had a nonfatal myocardial infarction (3.4%); and 79 patients (8.4%) developed unstable angina in the first year. Exercise testing improved proportional hazards models constructed from clinical variables for all three end points (p < 0.05). The perfusion scan further improved models for the end points (nonfatal infarction or cardiac death and cardiac death alone, p < 0.05). However, the exercise test with or without thallium added little to the overall prediction of primary events (area under the receiver operating curve increased from 0.649 to 0.663), and only 2% to 13% of patients with abnormal results either had a nonfatal infarction or died. CONCLUSIONS: Thallium-201 scintigraphy and exercise testing variables identify patients at risk for subsequent cardiac events. However, the poor predictive performance of these tests in this group of patients with stable coronary disease severely limits their usefulness. These results suggest a limited role for exercise and thallium testing in predicting cardiac events in patients with known coronary disease.

Coronary Disease↗