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Paolo Raggi

Publications and source records attributed to Paolo Raggi.

72 records · Page 4Linked to original sources
PubMed2002

Continuous probabilistic prediction of angiographically significant coronary artery disease using electron beam tomography.

BACKGROUND: We sought to incorporate electron beam tomography-derived calcium scores in a model for prediction of angiographically significant coronary artery disease (CAD). Such a model could greatly facilitate clinical triage in symptomatic patients with no known CAD. METHODS AND RESULTS: We examined 1851 patients with suspected CAD who underwent coronary angiography for clinical indications. An electron beam tomographic scan was performed in all patients. Total per-patient calcium scores and separate scores for the major coronary arteries were added to logistic regression models to calculate a posterior probability of the severity and extent of angiographic disease. These models were designed to be continuous, adjusted for age and sex, corrected for verification bias, and independently validated in terms of their incremental diagnostic accuracy. The overall sensitivity was 95%, and specificity was 66% for coronary calcium to predict obstructive disease on angiography. With calcium scores >20, >80, and >100, the sensitivity to predict stenosis decreased to 90%, 79%, and 76%, whereas the specificity increased to 58%, 72%, and 75%, respectively. The logistic regression model exhibited excellent discrimination (receiver operating characteristic curve area, 0.842+/-0.023) and calibration (chi2 goodness of fit, 8.95; P=0.442). CONCLUSIONS: Electron beam tomographic calcium scanning provides incremental and independent power in predicting the severity and extent of angiographically significant CAD in symptomatic patients, in conjunction with pretest probability of disease. This algorithm is most useful when applied to an intermediate-risk population.

Adult↗
PubMed2002

Usefulness of electron-beam computed tomography.

The field of atherosclerosis imaging has expanded rapidly in the last decade, and technologies such as electron-beam computed tomography (EBCT), have contributed significantly to our understanding of the prevalence of silent coronary artery disease and its consequences. Nonetheless, proper use of technology is necessary to conduct effective and cost-beneficial screening programs. Because most adverse events related to atherosclerosis occur in individuals at an intermediate risk level, it seems appropriate to concentrate screening efforts on this group of patients. This article reviews the current understanding of the value of coronary artery calcium screening in asymptomatic individuals and in symptomatic patients at low-to-intermediate risk and the use of EBCT as a tool for assessing the efficacy of therapy for atherosclerosis.

Adult↗
PubMed2002

Cardiac calcification in adult hemodialysis patients. A link between end-stage renal disease and cardiovascular disease?

OBJECTIVES: We sought to determine clinical and laboratory correlates of calcification of the coronary arteries (CAs), aorta and mitral and aortic valves in adult subjects with end-stage renal disease (ESRD) receiving hemodialysis. BACKGROUND: Vascular calcification is known to be a risk factor for ischemic heart disease in non-uremic individuals. Patients with ESRD experience accelerated vascular calcification, due at least in part to dysregulation of mineral metabolism. Clinical correlates of the extent of calcification in ESRD have not been identified. Moreover, the clinical relevance of calcification as measured by electron-beam tomography (EBT) has not been determined in the ESRD population. METHODS: We conducted a cross-sectional analysis of 205 maintenance hemodialysis patients who received baseline EBT for evaluation of vascular and valvular calcification. We compared subjects with and without clinical evidence of atherosclerotic vascular disease and determined correlates of the extent of vascular and valvular calcification using multivariable linear regression and proportional odds logistic regression analyses. RESULTS: The median coronary artery calcium score was 595 (interquartile range, 76 to 1,600), values consistent with a high risk of obstructive coronary artery disease in the general population. The CA calcium scores were directly related to the prevalence of myocardial infarction (p < 0.0001) and angina (p < 0.0001), and the aortic calcium scores were directly related to the prevalence of claudication (p = 0.001) and aortic aneurysm (p = 0.02). The extent of coronary calcification was more pronounced with older age, male gender, white race, diabetes, longer dialysis vintage and higher serum concentrations of calcium and phosphorus. Total cholesterol (and high-density lipoprotein and low-density lipoprotein subfractions), triglycerides, hemoglobin and albumin were not significantly related to the extent of CA calcification. Only dialysis vintage was significantly associated with the prevalence of valvular calcification. CONCLUSIONS: Coronary artery calcification is common, severe and significantly associated with ischemic cardiovascular disease in adult ESRD patients. The dysregulation of mineral metabolism in ESRD may influence vascular calcification risk.

Adult↗
PubMed2002

High coronary artery calcium scores pose an extremely elevated risk for hard events.

OBJECTIVES: We sought to assess the natural history of a cohort of asymptomatic individuals with very high (> or = 1,000) calcium scores (CSs) on a screening electron beam tomography (EBT) not submitted to further testing after the initial scan. We also compared the outcome of our prospective cohort with that of historical controls with severe abnormalities on myocardial perfusion imaging (MPI). BACKGROUND: Coronary calcium detected on EBT imaging has been shown to correlate with the total plaque burden. However, there is still controversy as to the prognostic significance of calcium, as some investigators believe that the presence of coronary calcification may stabilize the atherosclerotic plaque. METHODS: Ninety-eight asymptomatic subjects (mean age: 62 +/- 10) were followed for an average of 17 +/- 11 months (range: 4 to 36 months) after undergoing EBT screening for the occurrence of hard coronary events (HCEs), defined as myocardial infarction or coronary death. All patients had an initial CS > or = 1,000, and in none did the results of the EBT screening lead to further invasive or non-invasive testing. RESULTS: During the follow-up period, 35 patients (36%) suffered an HCE. All events were recorded in the first 28 months of follow-up. Subjects with HCEs had higher initial CSs than subjects not suffering HCEs (1,561 +/- 270 vs. 1,199 +/- 200, p < 0.001). The annualized event rate in subjects with a CS > or = 1,000 was significantly greater than that of historical controls with severe perfusion abnormalities on MPI (25% vs. 7.4%, respectively; p < 0.0001). CONCLUSIONS: A high CS (> or = 1,000) on a screening EBT in an asymptomatic person portends a very high risk of an HCE in the short term. This risk appears to be greater than the risk associated with a severe perfusion abnormality on MPI.

Aged↗
PubMed2002

Sevelamer attenuates the progression of coronary and aortic calcification in hemodialysis patients.

BACKGROUND: Cardiovascular disease is frequent and severe in patients with end-stage renal disease. Disorders of mineral metabolism may contribute by promoting cardiovascular calcification. METHODS: We conducted a randomized clinical trial comparing sevelamer, a non-absorbed polymer, with calcium-based phosphate binders in 200 hemodialysis patients. Study outcomes included the targeted concentrations of serum phosphorus, calcium, and intact parathyroid hormone (PTH), and calcification of the coronary arteries and thoracic aorta using a calcification score derived from electron beam tomography. RESULTS: Sevelamer and calcium provided equivalent control of serum phosphorus (end-of-study values 5.1 +/- 1.2 and 5.1 +/- 1.4 mg/dL, respectively, P = 0.33). Serum calcium concentration was significantly higher in the calcium-treated group (P = 0.002), and hypercalcemia was more common (16% vs. 5% with sevelamer, P = 0.04). More subjects in the calcium group had end-of-study intact PTH below the target of 150 to 300 pg/mL (57% vs. 30%, P = 0.001). At study completion, the median absolute calcium score in the coronary arteries and aorta increased significantly in the calcium treated subjects but not in the sevelamer-treated subjects (coronary arteries 36.6 vs. 0, P = 0.03 and aorta 75.1 vs. 0, P = 0.01, respectively). The median percent change in coronary artery (25% vs. 6%, P = 0.02) and aortic (28% vs. 5%, P = 0.02) calcium score also was significantly greater with calcium than with sevelamer. CONCLUSIONS: Compared with calcium-based phosphate binders, sevelamer is less likely to cause hypercalcemia, low levels of PTH, and progressive coronary and aortic calcification in hemodialysis patients.

Adult↗
PubMed2002

Effects of excess calcium load on the cardiovascular system measured with electron beam tomography in end-stage renal disease.

Cardiovascular disease is the leading cause of morbidity and mortality in dialysis patients and current research indicates that it might be linked to high serum phosphorus levels and calcium-phosphorus product. The severe osteopathy known to exist in end-stage renal disease (ESRD) patients is often coupled with an inability of bone to handle excess calcium loads. This might predispose to overflow and deposition of calcium and phosphate crystals in various soft tissues and in particular the cardiovascular apparatus. Atherosclerosis is a slow process that expands in the context of the arterial intimal layer and it is for the most part associated with extracellular calcification. Electron beam tomography (EBT) is a radiological technique utilized to non-invasively visualize this silent marker of atherosclerosis: vascular calcification. Several investigations conducted in non-ESRD patients have conclusively demonstrated that coronary calcification indicates a high risk for cardiac events. As EBT allows precise estimates of the extent of vascular and valvular calcification, it might become an important clinical tool in ESRD patients to assess the effect of excess calcium and phosphate load in soft tissues, estimate the cardiovascular risk of events and gauge the effectiveness of therapy.

Calcium↗
PubMed2002

Phosphorus restriction and control of coronary calcification as assessed by electron beam tomography.

PURPOSE OF REVIEW: Patients suffering from end-stage renal disease and undergoing dialysis demonstrate extremely elevated cardiovascular morbidity and mortality rates. Though the prevalence of traditional risk factors is very high, the extent and severity of cardiovascular complications seem disproportionate to the underlying risk profile. RECENT FINDINGS: A growing body of evidence indicates that abnormalities of calcium and phosphorus metabolism may play an important role in the morbidity and mortality of end-stage renal disease patients. Calcification of several cardiovascular structures, a likely complication of hyperphosphatemia and excessive calcium load, is both highly prevalent and extensive in end-stage renal disease patients and carries a negative prognostic weight. The extent of calcification can be accurately quantified with noninvasive radiological techniques such as electron beam tomography. Utilizing electron beam tomography in patients undergoing dialysis it has been possible to demonstrate the rapid progression of cardiovascular calcification and to gauge the effect of treatment provided to slow such process. SUMMARY: The presence of deleterious cardiovascular calcification in end-stage renal disease can be diagnosed accurately and noninvasively with electron beam tomography. This technology also allows precise assessment of the effect of medical treatment for hyperphosphatemia on calcification of cardiovascular structures.

Calcinosis↗
PubMed2002

Calcium scoring of the coronary artery by electron beam CT: how to apply an individual attenuation threshold.

OBJECTIVE: Our aim was to assess the inter- and intraindividual variability of the attenuation threshold used to identify coronary artery calcification on electron beam CT and to illustrate a new threshold method. MATERIALS AND METHODS: We measured the soft-tissue attenuation of regions surrounding the coronary arteries at the level of the left main coronary artery ostium (high level) and at the bottom of the heart (low level) in 48 consecutive patients (22 men, 26 women). Mean +/- 2 standard deviations (SD) of soft-tissue attenuation and variance of soft-tissue density and SDs were calculated at each level for every patient. It was assumed that setting an attenuation threshold greater than or equal to 3 SDs above that of soft tissue at each myocardial level would eliminate 99.5% of all scatter artifacts, allowing precise identification of calcific deposits. RESULTS: For the entire patient cohort, the average soft-tissue attenuation was 41 H and 35 H at the high and low levels, respectively (p < 0.01), indicating a large intraindividual variability. The SDs of soft-tissue attenuation measured by the computer software at the high and low levels were not different (26 H at the high level and 28 H at the low level; p = not significant). However, the calculated SD of the individual mean soft-tissue attenuation was 5 H at the high level and 8 H at the low level, again indicating a large intraindividual variability (p < 0.01). The addition of 3 measured SDs above the mean individual soft-tissue attenuation predicted a mean threshold of 120 and 121 H at the high and low levels, respectively, but with a wide interindividual variability (83-193 H at the high level and 79-242 H at the low level). There was a strong correlation between body weight and SD of soft-tissue attenuation at the low level (r = 0.75, p < 0.001) and a weaker but statistically significant correlation between weight and SD of soft-tissue attenuation at the high level (r = 0.51, p < 0.001). CONCLUSION: For the patients in this study, a threshold of 120 H for the detection of coronary calcification by electron beam CT seemed more appropriate than a threshold of 130 H, which is currently in use. However, given the great inter- and intraindividual variability, a biologic threshold tailored to the individual patient and to each individual imaging level should be used instead of a fixed threshold.

Aged↗
PubMed2002

[Electron beam computed tomography as a method to study coronary atherosclerosis].

Coronary artery disease is very prevalent in western countries and it represents the most frequent cause of death for both men and women. In the United States over 7 million people suffer from this ailment and about 500,000 die each year from its complications. Often the presenting event is an acute myocardial infarction or sudden death and the cost for society both financial and in terms of human lives lost is excessive. Despite the emphasis on prevention of atherosclerosis, unheralded events continue to occur in the general population in the absence of established risk factors. Indeed, risk factors justify only 60-70% of the risk of events for an individual patient. The focus of research has therefore turned to the application of non-invasive modalities for the imaging of the atherosclerotic plaque in its pre-clinical stages. The aim is to apply this information to guide a physician in choosing the patient in need of more aggressive preventive measures. One such imaging modality, electron beam tomography, is employed to visualize the calcified component of the atherosclerotic plaque. Calcium deposition in the wall of the coronary arteries is a highly sensitive and specific marker of atherosclerotic disease. This article summarizes the extensive amount of research published during the past 15 years on the use of calcium imaging as a tool to predict events.

Coronary Artery Disease↗
PubMedDate not supplied

Computed tomography coronary calcium screening and myocardial perfusion imaging.

Cardiac computed tomography (CT) has seen an exponential increase in interest as applications expanded from identification of coronary artery calcification to noninvasive coronary angiography and, more recently, identification of soft and noncalcified plaques. The interest arises from the well-known fact that cardiovascular disease remains the most prevalent cause of death in the Western hemisphere and the fact that in a large proportion of patients the initial event is either sudden death or a disabling myocardial infarction or stroke. Although traditional risk factors are extremely helpful in determining risk in a population, the prognostic ability of risk factors alone in the individual patient is limited. Hence, researchers have turned their attention to noninvasive modalities to image the atherosclerotic plaque in its preclinical stages, hoping to better address this ailment at its inception and change the natural history of the disease. Measurements of coronary artery calcium (CAC) serve as a quantitative reflection of the severity of coronary artery atherosclerosis, and greater calcium burdens correlate with more advanced disease. Indeed, CAC has been shown to add prognostic value to traditional risk factors in patients at intermediate risk, and in this group of patients, it is most cost-effective. Furthermore, CAC measurements providing an assessment of coronary atherosclerotic plaque burden appear to be complementary to myocardial perfusion single photon emission computed tomography that offers information regarding inducible ischemia. In this manner, a better assessment of risk in a patient suspected of harboring preclinical or early coronary artery disease can be achieved. In this article we review the most relevant literature regarding the utilization of CAC testing as a tool to refine risk assessment and use several case studies to exemplify the combination of CT imaging and functional myocardial perfusion studies, which may provide a better identification of patients in need of aggressive medical therapy and those needing invasive assessment for possible coronary revascularization.

Aged↗
PubMedDate not supplied

Cost effectiveness of screening for cardiovascular disease with measures of coronary calcium.

Cardiovascular disease is the leading cause of morbidity and mortality with annual costs of care exceeding 300 billion US dollars. Although screening tools are advocated for many cancers, the use of subclinical disease tests for cardiovascular disease are considered controversial. Health care payers and many governmental agencies apply cost-effectiveness analysis for the evaluation of new technology being considered for routine application in the US and Europe. Cost-effectiveness analysis by definition provides a comparative analysis of clinical and economic outcome data when evaluating new technology in relation to existing modalities. The current report provides a description of the framework upon methods applied in cost-effectiveness analysis as well as available data on the subject of cardiovascular screening, most notably using the evaluation of coronary calcium screening with electron beam tomography. The current report will also present several decision analytic models on the cost of atherosclerotic imaging including the evaluation of serial monitoring for disease progression and the development of cost-effectiveness models employing intermediate outcomes. Based on this review, there is an unfolding body of evidence that explores both the clinical and economic consequences of screening for atherosclerotic diseases. Although further evidence is required from prospectively designed randomized controlled trials, it appears that the current evidence from small series and decision analytic models supports cardiovascular screening of asymptomatic individuals and that the current results reveal enhanced cost effectiveness when compared with the routine evaluation using a Framingham risk assessment.

Calcinosis↗
PubMedDate not supplied

Electron beam tomography in women. Is it a valuable test?

Cardiovascular disease (CVD) is the leading cause of mortality in women and a major cause of morbidity. Coronary artery disease (CAD) accounts for nearly half of all CVD deaths. Traditional risk factors are very helpful in predicting the development of CAD in women; however, many women suffer events in the absence of established risk factors for atherosclerosis. To meet the challenge of CAD, several tools have been developed to identify atherosclerotic disease in its preclinical stages, with the hope of modifying its natural history. In this article, we review the current literature on utilization of electron beam tomography (EBT) for detection of CAD as a tool to conduct risk stratification in the general asymptomatic female population as well as among asymptomatic women. In conclusion, EBT can be used to estimate the overall coronary atherosclerotic plaque burden in women. It can also be used to diagnose its presence and determine its extent; furthermore, information from the coronary artery calcium scores can be used to assess the likelihood of obstructive disease and to provide prognostic information. Finally, EBT has the potential to determine the consequences of therapeutic interventions regarding progression, stabilization, or regression of coronary atherosclerotic disease.

Calcinosis↗
PubMedDate not supplied

Electron beam tomography to image cardiovascular calcifications in hemodialysis patients.

Cardiovascular disease is the leading cause of death in western countries and it is especially frequent in dialysis patients. Though for a long time physicians have been mainly focused on the severity of luminal coronary stenosis, atherosclerosis starts and expands in the contest of the arterial wall much before it extends into the vessel lumen. Indeed, most acute coronary events occur in patients with non-obstructive luminal disease. On pathological examination patients with end stage renal disease (ESRD) show larger and more extensively calcified atherosclerotic lesions than non-uremic patients. Recent evidence shows that even very young dialysis patients show premature calcification of the coronary arteries. Therefore, early detection of atherosclerotic disease with a non-invasive imaging technology such as electron beam tomography (EBT) may provide an opportunity to modify the disease course and reduce the related event rate.

Cardiovascular Diseases↗
PubMedDate not supplied

Coronary-calcium screening to improve risk stratification in primary prevention.

Coronary artery disease is very prevalent in the United States where over 7 million people suffer from it, and more than 500,000 die from its complications annually. For the majority of individuals suffering an acute myocardial infarction, the event represents the first indication of the presence of underlying coronary atherosclerosis. Furthermore, due to the outward remodeling of arteries that slowly accumulate atheroma in their imtima (Glagov effect), sudden death or acute myocardial infarction may occur in the absence of obstructive luminal atherosclerotic plaque. Therefore, it might seem highly desirable to detect atherosclerosis in its early stages to implement effective preventive measures rather than apply delayed treatment. Yet, statistics from primary care and sub-specialty practices indicate that the preventive attitude of the majority of physicians is not sufficiently developed, and most training programs still struggle to implement strong educational curricula in this field. To these limitations, one may add that traditional risk factors help predict only about 60% to 65% of the risk, while many individuals continue to suffer events in the absence of established risk factors for atherosclerosis. In light of this knowledge, several tools have been developed to identify atherosclerotic disease in its pre-clinical stages in the hope of modifying its natural history. This review deals with the utilization of electron beam tomography for detection of coronary arterial calcium as an additional tool to risk stratify asymptomatic individuals.

Calcinosis↗
PubMedDate not supplied

Screening for silent ischemia with coronary artery calcium and nuclear stress testing in nondiabetic patients prior to kidney transplant.

Whether coronary artery calcium (CAC) screening in pretransplant patients may help predict silent myocardial ischemia is unknown. Accordingly, we performed CAC imaging on 46 nondiabetic patients awaiting kidneytransplant. All patients underwent multidetector computed tomography imaging for CAC quantification, and a vasodilator myocardial perfusion stress (MPS) test was performed only in patients with a total CAC score>300 or>100 in a single coronary artery. The mean patient's age was 46+/-14 years and the median dialysis vintage was 33 months (interquartile range 19-53). The median CAC score was 82 (interquartile range 0-700) and correlated with patients' age (p=0.006) and dialysis vintage (p=0.02). Nineteen patients qualified for MPS, but 5 refused the test. Of the remaining 14 patients, 7 patients had normal scans and 7 showed a minimal perfusion defect in the inferoposterior segment of the left ventricle. At the time of writing, 12 patients have undergone successful kidney transplantation without untoward complications. CAC screening does not appear to be associated with silent ischemia in pretransplant patients. Though CAC is extensive in dialysis patients, calcium may be associated with nonobstructive atherosclerotic lesions or calcification of the media layer of the vessel wall.

Adult↗