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Contrast echocardiography: effects of microbubbles on coronary blood flow and left ventricular hemodynamics
P R Silverman1, S B Feinstein, R M Lang
1Department of Medicine, University of Chicago, Illinois 60637.
Insights
This study investigated the physiological effects of contrast agents used in echocardiography. Results show transient changes in coronary blood flow and systemic blood pressure following injections, with microbubbles potentially influencing these responses.
Area of Science:
- Cardiovascular Physiology
- Diagnostic Imaging
- Pharmacology
Background:
- Contrast echocardiography is used for myocardial perfusion assessment during cardiac catheterization.
- Existing data on the physiological effects of microbubble contrast agents are limited and conflicting.
Purpose of the Study:
- To evaluate the physiological effects of microbubble-containing contrast agents on coronary blood flow, blood pressure, and heart rate.
- To determine if microbubbles influence the physiological response to contrast agents.
Main Methods:
- Six dogs were studied using an electromagnetic flow meter to measure coronary blood flow.
- ECG-gated power injector delivered various sonicated and nonsonicated contrast agents (saline, Renografin-76, dextrose, sorbitol).
- Simultaneous recordings of left ventricular images and systemic blood pressure were obtained.
Main Results:
- Coronary blood flow initially decreased (-1% to -10%) then increased (+11% to +29%) post-injection.
- Systemic blood pressure showed transient increases during injection, followed by declines in systolic (-5% to -18%) and diastolic (-13% to -33%) pressures.
- Blood pressure returned to above control levels within 20-30 seconds post-injection.
Conclusions:
- Contrast agent injections cause temporary alterations in coronary blood flow and systemic hemodynamics.
- Further research is needed to fully elucidate the role of microbubbles in these physiological responses.
Abstract:
Contrast echocardiography is currently being used to define and quantitate myocardial perfusion at the time of cardiac catheterization. Limited and conflicting data exist regarding the physiologic effects of microbubble-containing contrast agents. In the present study, coronary blood flow measured using an electromagnetic flow meter, blood pressure, and heart rate responses were studied in six dogs. An ECG-gated power injector was used to deliver 7 to 9 ml of sonicated and nonsonicated solutions (saline, Renografin-76, dextrose 50% and 70%, and sorbitol 70%) through an intra-aortic catheter placed above the aortic cusps. Paired injections of sonicated and nonsonicated agents were compared to determine whether the presence of microbubbles affected the physiologic response to these agents. Simultaneous recordings of two-dimensional cross-sectional images of the left ventricle were obtained. Data are expressed as percentage of change from preinjection control values. Within 10 seconds of an injection, decreases in coronary blood flow occurred in a range from -1 to -10% compared with preinjection control values. Coronary blood flow increased between 10 and 25 seconds postinjection within a range from +11 to +29%. Systemic blood pressures rose during injections and then declined below control values within 10 seconds. The magnitude of the decline in systolic blood pressure ranged from -5. to -18%. Diastolic blood pressure declined in a range from -13 to -33%. Within 20-30 seconds postinjection, systemic blood pressure rose above control values. The magnitude of the systolic and diastolic blood pressure rise ranged from +4 to +11%.(ABSTRACT TRUNCATED AT 250 WORDS)