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Anthony N DeMaria

Publications and source records attributed to Anthony N DeMaria.

At least 73 records · Page 4Linked to original sources
PubMed2003

Assessment of right ventricular perfusion after right coronary artery occlusion by myocardial contrast echocardiography.

OBJECTIVES: The purpose of this study was to examine the ability of myocardial contrast echocardiography (MCE) to assess right ventricular (RV) perfusion. BACKGROUND: Although MCE can readily assess left ventricular perfusion abnormalities, there are no data regarding the ability to assess RV perfusion abnormalities. METHODS: The right coronary artery (RCA) was occluded in 10 open-chest dogs. Myocardial contrast echocardiography was performed with 0.27 g/min Levovist infusion by harmonic power Doppler with electrocardiographically gated intermittent triggered imaging at pulsing intervals ranging from 1:1 to 1:20 at baseline and 90 min after RCA occlusion. Video-intensity of the RV wall was plotted against pulsing intervals and was fitted to an exponential function: y = A(1-exp(-bt)), where A is the plateau video-intensity and b is the rate of video-intensity rise. Myocardial contrast echocardiography and microsphere-derived myocardial blood flow (MBF) measurements were performed at baseline and 90 min after RCA occlusion. RESULTS: Because the severity of RV perfusion abnormalities assessed by MBF varied during RCA occlusion, diverse grades of patchy opacification defects were observed by MCE. The RV wall thickness decreased, and the RV dimension increased, after RCA occlusion in each dog. The correlation of occlusion to baseline MBF ratios in the RV wall was closer to the ratio of b (r = 0.897, p = 0.0004) than A (r = 0.767, p = 0.0097) and was the closest to the ratio of Axb (r = 0.935, p < 0.0001). CONCLUSIONS: The RCA occlusion is manifested by RV wall thinning and dilation as well as by perfusion abnormalities consisting of patchy opacification defects by MCE. Myocardial contrast echocardiography-derived refilling parameters can be applied to assess RV perfusion abnormalities produced by RCA occlusion.

Animals↗
PubMed2003

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PubMed2003

Effect of microbubble fragility on transit rate measurement by contrast echography.

We sought to propose a simplified method to measure flow velocity based on ultrasonic microbubble destruction, and investigated the effect of microbubble shell fragility on such measurement. Acoustic density (AD) from the second harmonic short axis image of flow was obtained at variable velocities (2 to 73 mm/s) in an in vitro model during long (1000 ms) and short (33 ms) interval ultrasound (US) pulsing, allowing complete and partial microbubble replenishment between pulses, respectively. Microbubbles with shell elastic modulus of 0.4 MPa and 16 MPa were tested. By shortening pulsing interval, AD diminished gradually, rather than abruptly, to a plateau level for both microbubbles. The extent of AD decay was greater for the fragile than the strong microbubbles. A linear relationship existed between the magnitude of AD decay and flow velocity only in the higher and lower velocity range for the fragile and the strong microbubbles, respectively. Thus, difference in contrast intensities during long and short pulsing intervals, respectively, allowing complete and partial replenishment may provide for velocity measurement, in which choice of optimal microbubble fragility for the range of velocity to measure may increase the accuracy.

Capsules↗
PubMed2003

Coxibs--beyond the GI tract: renal and cardiovascular issues.

Although the coxibs have demonstrated superior gastrointestinal safety compared to traditional non-selective NSAIDs, questions remain regarding their effects on the renal and cardiovascular systems. In terms of renal function, both Type 1 and Type 2 cyclooxygenase (COX-1 and COX-2) are expressed constitutively in the kidney. Prostaglandins do not play a major role in the maintenance of renal function in healthy individuals but they become profoundly important in certain clinical situations such as renal stress, or volume depletion. In such situations the effects of the coxibs and non-selective NSAIDs are likely to be similar. The incidence of renal side effects is low (1-5%) and the patients at risk of renal complications are well defined and can usually be identified prospectively and followed up as appropriate. From the cardiovascular point of view, questions have been raised as to whether the coxibs have a prothrombotic effect. Here we review the available evidence and consider various hypotheses for an apparent increase in cardiovascular events reported in one coxib study (the VIGOR trial). Because of a lack of anti-platelet activity, coxibs are not suited for the provision of cardiovascular prophylaxis, and in patients at risk of myocardial infarction the prophylactic use of aspirin should always be considered. Although evidence suggests that use of coxibs with low-dose aspirin is safer than the combination of traditional NSAIDs with aspirin, further studies are required to confirm that this is the case.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2003

Time requirements of the standard echocardiogram: implications regarding limited studies.

BACKGROUND: Although no formal detailed definitions exist, a standard echocardiogram should easily be differentiated from a limited examination by its comprehensive nature and time requirement. OBJECTIVE: We evaluated the time required to perform each specific component of a comprehensive echocardiography examination and applied these data to compare the time required to complete 3 limited imaging protocols. METHODS: In all, 7 experienced sonographers were timed in their performance of a comprehensive echocardiographic examination on a healthy patient. A total of 3 limited imaging protocols were then constructed to evaluate for pericardial effusion, wall motion, and left ventricle size. The time necessary to complete each protocol was calculated by adding the average time required to perform all of its components and was compared with the comprehensive examination. RESULTS: The imaging time required to complete a standard study was 26 +/- 5.4 minutes (range: 20-32). The percentage of total study time spent on 2-dimensional imaging, M-mode, color Doppler, and spectral components was 31 +/- 2.9%, 11 +/- 3.6%, 17 +/- 2.9%, and 39 +/- 5.0%, respectively. The calculated time needed to perform a limited protocol was less than 5 minutes, resulting in a greater than 80% reduction in time compared with the standard examination. CONCLUSION: Time analysis of components of the standard echocardiography examination can be used to construct appropriate, time-efficient, limited, cardiac ultrasound imaging examinations and differentiate limited from comprehensive studies.

California↗
PubMed2003

Difference of optimal dose of contrast agent between gray-scale and power Doppler imaging in assessing graded coronary stenosis by myocardial contrast echocardiography.

RATIONALE AND OBJECTIVES: In myocardial contrast echocardiography (MCE), power Doppler imaging is more sensitive to contrast agent (microbubble) than gray-scale B-mode imaging; however, no data exist regarding the optimal contrast dose in power Doppler imaging. This study examined the optimal dose of contrast agent for power Doppler in assessing coronary stenosis. METHODS: Three grades of coronary stenosis were produced in 6 open-chest dogs. MCE was performed with gray-scale and power Doppler during continuous infusion of 0.2 mL/min FS-069. Thereafter, MCE was repeated with power Doppler during continuous infusion of 0.1 mL/min FS-069. RESULTS: Although the videointensity in the stenosed bed with power Doppler (214 +/- 14) was greater than gray scale (35 +/- 17) during 0.2 mL/min FS-069 infusion (P < 0.0001), power Doppler failed to identify milder coronary stenoses because videointensity in stenosed bed was quickly saturated with contrast agent. The videointensity in the stenosed bed with power Doppler (127 +/- 49) during 0.1 mL/min FS-069 infusion was greater than gray scale (35 +/- 17) during 0.2 mL/min FS-069 infusion (P < 0.0001), and all levels of stenosis were identified with power Doppler, even though the dose of contrast agent was half of that of gray scale imaging. The correlation between videointensity and myocardial blood flow was better in the case of power Doppler at 0.1 mL/min FS-069 infusion (r = 0.77, P < 0.0001) than in the case of gray scale imaging at 0.2 mL/min FS-069 infusion (r = 0.66, P < 0.01). CONCLUSIONS: These data support the need for a lower dose of contrast agent for power Doppler than for gray scale to detect milder coronary stenosis and avoid saturation of imaging fields.

Animals↗
PubMed2002

Physical principles of microbubble ultrasound contrast agents.

Early contrast agents could not achieve left-sided cardiac opacification because these microbubbles could not traverse the pulmonary circulation and remain intact. The specific shell material and gas used determine the properties of individual microbubbles, including fragility, persistence, and resonance. Persistence, perhaps the most important property of a microbubble, has been achieved by second-generation agents through the use of shells or surfactants and by substituting high-density, high molecular weight gas for air. Today's agents readily achieve opacification, not only of the cardiac chambers but also of the myocardium. Refinements in contrast agents and in the instrumentation for their detection are primarily responsible for these improvements.

Contrast Media↗
PubMed2002

Correlation of left ventricular diastolic filling characteristics with right ventricular overload and pulmonary artery pressure in chronic thromboembolic pulmonary hypertension.

OBJECTIVES: This study was designed to determine a quantitative relationship between right ventricular (RV) pressure overload and left ventricular (LV) diastolic filling characteristics in patients with chronic thromboembolic pulmonary hypertension (CTEPH). BACKGROUND: Right ventricular pressure overload in patients with CTEPH causes abnormal LV diastolic filling. However, a quantitative relationship between RV pressure overload and LV diastolic function has not been established. METHODS: We analyzed pre- and postoperative diastolic mitral inflow velocities and right heart hemodynamic data in 39 consecutive patients with CTEPH over the age of 30 (55 +/- 11 years) with mean pulmonary artery pressure >30 mm Hg who underwent pulmonary thromboendarterectomy (PTE). RESULTS: After PTE, mean pulmonary artery pressure (mPAP) decreased from 50 +/- 11 to 28 +/- 9 mm Hg (p < 0.001) while cardiac output (CO) increased from 4.4 +/- 1.1 to 5.7 +/- 0.9 l/m (p < 0.001). Mitral E/A ratio (E/A) increased from 0.74 +/- 0.22 to 1.48 +/- 0.69 (p < 0.001). E/A was < 1.25 in all patients pre-PTE. After PTE, all patients with E/A >1.50 had mPAP <35 mm Hg and CO >5.0 l/min. E/A correlated inversely with mPAP (r = 0.55, p < 0.001) and directly with CO (r = 0.53, p < 0.001). CONCLUSIONS: E/A is consistently abnormal in patients with CTEPH and increases post-PTE. Moreover, E/A varies inversely with mPAP and directly with CO. Following PTE, E/A >1.5 correlates with the absence of severe pulmonary hypertension (mPAP >35 mm Hg) and the presence of normal cardiac output (> 5.0 l/m).

Aged↗