American journal of cardiac imaging最新文献

Along with hypertrophy of the left ventricle (LV), hypertrophic cardiomyopathy (HC) is characterized by LV outflow tract (LVOT) obstruction, partly from systolic anterior motion (SAM) of the anterior mitral leaflet; if obstruction is significant, excision of excess subaortic septal myocardium may be indicated. In this study, the ability of computed tomography magnetic resonance imaging (Cine MRI) to provide information about LVOT obstruction was assessed in a series of 37 HC cases undergoing evaluation, including echocardiography (0 to 14 days before), for possible septal myectomy; in 4 cases, Cine MRI was used postsurgically (5 to 25 months after). Blinded to echocardiography results, 3 reviewers analyzed by consensus the Cine-MRI LVOT-long-axis image-loops for SAM grade (none, mild, severe) and "aorta:LVOT signal ratio" (intensity in descending aorta/intensity in LVOT at maximum systolic-flow disturbance). Resting LVOT flow velocities were separately determined using Doppler analysis, permitting differentiation between insignificant (< 30 mm Hg) and significant (< or = 30 mm Hg) gradients. With echocardiography, significant resting obstruction was found in 62% of cases, including 92% treated surgically. A significant association between SAM grade and obstruction was found; all cases with a SAM grade of none had insignificant ([-] predictive value: 100%) and most with a severe grade had significant ([+] predictive value: 78%) obstruction. Signal ratio in the absence of a significant gradient was significantly lower than in its presence; a significant linear relationship between aorta:LVOT signal ratio and resting gradient was found: LVOT gradient = ([2.9] x [signal ratio]) + 22.8. SAM grade did not contribute significantly in obstruction categorization when signal ratio was known. In all cases studied after surgery, SAM grade had decreased from severe to insignificant levels and aorta:LVOT signal ratio had been significantly reduced. Insights into the dynamic nature of the LVOT in HC patients can be provided by Cine MRI, either during their evaluation for surgery or after their septal myectomy.

The use of coronary angiography and coronary interventions in women with suspected coronary artery disease has recently come under close scrutiny. Clear differences in the utilization of these procedures, including coronary artery bypass graft (CABG) surgery have led to concerns that a bias may exist against the use of these procedures in women. Alternative explanations of these perceived practice differences have focused on their propriety based on patients' ages, underlying disease severity, expected prevalence of coronary disease and comorbid conditions rather than physician bias. The possibility that these procedures are over utilized in men has also been suggested. Pertinent to this debate are historical observational data suggesting that women may be at higher risk of major complications of coronary interventions and CABG surgery. Because coronary artery disease is the most frequent cause of death among women in the United States, there is some sociopolitical urgency in addressing these important concerns. This article reviews the use and findings of diagnostic coronary angiography in women with suspected coronary artery disease. Specific risks to women who have coronary angiography performed are also discussed. Finally, the outcome of percutaneous coronary revascularization procedures in women compared to men is discussed.

Diagnosis and assessment of coronary artery disease (CAD) is especially difficult in women. The history of chest discomfort and various noninvasive tests each have particular problems, which indicate the need to consider more accurate tests such as cardiac magnetic resonance imaging (MRI) and positron emission tomography (PET). MRI of cardiac function at rest and during dobutamine stress has good accuracy, and MR Myocardial perfusion imaging (MPI) with gadolinium DTPA looks promising. The most exciting MR method is cineangiography (MRA), which images blood flow through the coronary arterial lumen as an intense signal. In an initial clinical trial this method showed excellent sensitivity and fair specificity in patients in whom adequate images could be obtained. MR spectroscopy (MRS) has imaged changes in high energy phosphates in patients with severe coronary stenoses during handgrip exercise, but is still experimental. PET MPI corrects the images for attenuation problems that limit the use of other radionuclide imaging procedures in women more than in men. Many studies show excellent sensitivity and specificity to diagnose CAD by PET MPI. In view of its clinical validation and the safety of dipyridamole relative to dobutamine, PET MPI appears to be the best test for assessing CAD in women. The greater accuracy of PET (or perhaps of fully developed MRI/MRA systems) will produce better clinical outcomes and cost-effectiveness for most patients than will less accurate modalities, despite their higher initial cost.

Myocardial uptake of iodine-123 meta-iodobenzylguanidine (123I-MIBG) was measured using scintigrams at rest in 12 patients with isolated, nonischemic mitral regurgitation (MR; regurgitant fraction 64% +/- 7%) and was related to the left ventricular (LV) function assessed by cardiac catheterization. Iodine-123 meta-iodobenzylguanidine activity in the upper mediastinum, liver, and lung was comparable between MR and control (n = 8) patients. The heart-to-mediastinum 123I-MIBG activity ratio 4 hours after injection was significantly (p < 0.01) decreased in MR (2.0 +/- 0.1, mean +/- SE) compared with control (2.7 +/- 0.1) with the increased clearance of MIBG. In addition, MR patients had significantly greater heterogeneity in the 123I-MIBG distribution within the myocardial images (26.1% +/- 2.1% intraimage variability for MR versus 15.6% +/- 0.8% for control, p < 0.01). Myocardial 123I-MIBG activity correlated positively with cardiac index and negatively with pulmonary capillary wedge pressure and LV volume indexes. Thus, 123I-MIBG scintigrams can be a noninvasive method for assessing the contractile dysfunction in MR.

Bileaflet prostheses are low profile, central flow orifice devices that show excellent hemodynamic performance and low thrombogenicity. Five models are currently used for heart valve replacement. Comprehensive and comparative studies regarding valve characteristics and functioning are lacking, making the updating and the familiarization by physicians and cardiologists with these prostheses difficult. We describe the valve design characteristics and evaluate the cine-fluoroscopic appearance and functioning of 387 bileaflet prostheses that have been implanted in 367 consecutive patients. The valve types are St Jude Medical (n = 69), Edwards-Duromedics (n = 74), Carbomedics (n = 1290) Sorin Bicarbon (n = 88) and Jyros (n = 27). The prostheses' fluoroscopic appearance was evaluated through multiple radiographic views (Siemens-Elema equipment with C-arm); the prostheses' functional evaluation was performed by obtaining the "tilting disk projection" (ie, with the radiographic beam parallel to both the valve ring plane and the tilting axis of disks) to calculate opening, closing, and travel angles of the disks. This study shows that each of the five bileaflet valves has distinctive design characteristics. Fluoroscopy is an easy, readily available, and useful technique that correctly identifies the prosthesis type and properly evaluates its functioning in the majority of cases.

Coronary artery disease (CAD) is the leading cause of adult mortality in the United States. Data collected from the era preceding contemporary revascularization techniques indicated that chest pain syndromes among women carried a more favorable cardiac prognosis than such symptoms in men. More recent information indicates that many women with chest pain do not have CAD and that, among those who do, clinical manifestations first appear an average of 10 years later than in men, at a time when risk factors and comorbidities such as diabetes, hypertension, and hypercholesterolemia are more prevalent. The toll that this disease exacts among women catches up with that among men after women go through menopause, so that coronary heart disease accounts for nearly equal annual mortality rates in the two genders and for more deaths among women than is attributable to all cancers. The initial, widely held impression that chest pain is more benign in women is being replaced by a growing awareness that coronary disease is not. It appears from published experience that any potential bias in the management of women with possible CAD is overcome once the diagnosis is established. It is clear that a reliable method for the evaluation of women with known or suspected CAD is required. Stress electrocardiography, perfusion imaging, and radioventriculography suffer from a number of limitations, particularly in women. This paper discusses the rationale for and performance of stress echocardiography. Although the specific application of this method in females has been the subject of relatively limited clinical investigations, we believe that it holds great promise as the diagnostic test of choice for women.

This article reviews the current knowledge about coronary artery calcification in women, concentrating on the pathophysiology of atherosclerotic calcification, the gender and age differences in the detection of calcification by electron beam computed tomography (EBCT), and the clinical significance of detected coronary calcium. The effects of estrogen and vitamin D on vascular calcification are examined with respect to data that point to similarities between the processes of calcification and bone matrix formation. Gender and age differences in EBCT coronary calcium detection, with emphasis on differences and consequences of calcium prevalence, are also examined. Lastly, the diagnostic and prognostic significance of coronary calcification is discussed, noting that it is more significant in symptomatic, older, and high-risk adults than it is in younger individuals of either gender.

Heart disease is a major threat to women's health. However, noninvasive evaluation of women for the presence of significant heart disease is often problematic. Cardiovascular nuclear tests interrogate different consequences of physiologically significant coronary artery disease (CAD). Myocardial perfusion imaging supplies information about regional myocardial blood flow. Radionuclide angiocardiography provides information about ejection fraction and regional wall motion. Infarct and metabolic imaging yield information about myocardial viability. This article briefly discusses the concepts and radionuclides involved in cardiovascular nuclear testing and reviews published studies as they relate to assessment of coronary artery disease in women. Myocardial perfusion imaging is a reasonable test for detection of coronary artery disease in women, especially when attenuation artifacts from breast tissue are taken into account. Intravenous dipyridamole stress provides comparable overall accuracy in women and men although women reportedly have a higher incidence of side effects; gender-specific data have not been reported for adenosine. Sufficient gender-specific data are also not currently available for either 99mTc or positron-emitting perfusion tracers. Exercise radionuclide angiography can help determine the probability of significant left main or severe three vessel disease but provides only limited prognostic information in women with CAD. Thus in women, although choice of testing using nuclear techniques depends in part on local experience and expertise, myocardial perfusion imaging appears preferable to radionuclide angiocardiography for detection of significant CAD. To determine the most accurate methods to evaluate women for the presence of significant CAD, all current and future studies of diagnostic testing for CAD should analyze data separately for women and men.

Hemodynamic changes induced by ventriculo-atrial retroconduction has been considered an important factor in pacemaker syndrome. The contraction of atrial muscles, when the mitral valve is closed, induces a reverse systolic flow into the pulmonary veins, because the outlet of the pulmonary vein in the left atrium is not protected by a valve. The profile of the pulmonary vein forward flow of 25 patients was examined using transesophageal echocardiography (TEE) technique. Doppler evaluation of velocity-time integrals of forward flow (fVTI) and reverse flow (rVTI) was measured both during sinus rhythm or fully automatic (DDD) pacing, and ventricular demand pacing (VVI) accompanied by ventriculoatrial (VA) retroconduction or atrioventricular (AV) dissociation. The mean fVTI was reduced from 21.1 cm +/- 6.2 cm in DDD or sinus rhythm (SR) to 16.4 cm +/- 6.6 cm in VVI (p < 0.001). The mean rVTI was increased from 1.4 cm +/- 0.8 cm in DDD or SR to 4.3 cm +/- 1.8 cm in VVI (p < 0.001). The degree of such alterations varied considerably from patient to patient and this may explain the variability of clinical symptoms reported for pacemaker syndrome. It has not been possible to establish a direct correlation between the magnitude of hemodynamic changes and the severity of the symptoms observed because all the patients were in sequential stimulation or in SR and were temporarily submitted to VVI stimulation during the echocardiographic examination.