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[Multiplane transesophageal echocardiography and adenosine in the study of coronary blood reserve]
Insights
Multiplane Transesophageal Echocardiography effectively assesses coronary blood flow reserve. In normal subjects, adenosine infusion significantly increased coronary blood flow velocity, indicating its utility in evaluating coronary artery function non-invasively.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Coronary blood reserve is crucial for myocardial energy supply.
- Coronary stenosis impairs vasodilation and blood flow capacity.
- Intracoronary Doppler is a standard tool for measuring coronary blood flow velocity.
Purpose of the Study:
- To evaluate Multiplane Transesophageal Echocardiography (MTEE) as a non-invasive tool.
- To assess anterior descending artery blood flow velocity before and after adenosine infusion.
- To compare MTEE findings with intracoronary Doppler capabilities.
Main Methods:
- 28 patients were divided into two groups: with (Group A) and without (Group B) significant coronary stenosis.
- MTEE with a 5 MHz multiplane probe was used to measure systolic and diastolic velocities in the anterior descending artery.
- Adenosine was infused to induce vasodilation, and velocities were measured at rest and after infusion.
Main Results:
- MTEE successfully visualized the anterior descending artery in 95% of patients.
- Adenosine infusion in Group B (normal subjects) resulted in a twofold increase in diastolic and systolic velocities.
- Adenosine/rest velocity ratios were statistically significant (V.MAX D. p < 0.02, V.MN.D. p < 0.03).
Conclusions:
- MTEE demonstrates significant capacity in evaluating coronary blood flow reserve.
- Adenosine is a suitable vasodilator due to its short half-life and repeatability.
- Flow velocity increases more than twofold in normal subjects, confirming MTEE's efficacy.
Background:
Coronary blood reserve is the capacity of coronary vessels to vasodilate and thereby to increase the blood flow, when the heart needs more energy. However, when a coronary stenosis occurs, the capacity to vasodilate is reduced or completely diminished. It is then necessary to use all the tools useful in evaluating the functional conditions of the coronary vessels. Above all, the intracoronary Doppler technique is used to measure the velocity of blood flow. Our purpose was to evaluate a non-invasive tool "Multiplane Transesophageal Echocardiography" in the study of velocity of the anterior descendent artery before and after adenosine infusion.
Methods:
At first, we studied 28 patients (pts), which we divided in two groups: Group A, 18 pts 59.38 +/- 8.23 mean age, 15 M. and 3 F., with anterior descending disease; Group B 10 pts, 59.20 +/- 8.48 mean age, 7 M. and 3 F, without significant stenosis (> 75%). Echocardiography examinations were performed with a 5 MHz multiplane probe, connected to a 1000 Hewlett Parkard echocardiography. Before the test, Diazepam 1 mg i.v. and Lidocaine spray were administered to the patients. We introduced the transesophageal probe and after choosing the best position of the aortic short axis view, we studied the anterior descending artery and measured the maximum and mean diastolic and sistolic velocities (V.MAX D., V.MN.D., V.MAX S., V.MN.S.).
Results:
Transesophageal echocardiography allowed us to study the anterior descending artery in 95% of pts. There were no side effects, except for one pt affected by severe bradicardia. In Group B there was an increase of the diastolic and sistolic velocity after adenosine infusion, resulting twice greater they the rest values. The adenosine/rest velocities ratios were statistically significant (V.MAX D. p < 0.02) (V.MN.D. p < 0.03).
Conclusion:
Our results demonstrated an higher capacity of the Multiplane Transesophageal Echocardiography in studiing coronary blood reserve. We used adenosine, as a vasodilator drug, because of its short half-life and because it can be replatedly infused. The flow velocity values increased up to more than twice the rest values only in normal subjects.