Abstract
BackgroundThe determination of coronary flow reserve (CFR) is an essential concept at the moment of decision-making in ischemic heart disease. There are several direct and indirect tests to evaluate this parameter. In this sense, dobutamine stress echocardiography is one of the pharmacological method most commonly used worldwide. It has been previously demonstrated that CFR can be determined by this technique. Despite our wide experience with dobutamine stress echocardiography, we ignored the necessary heart rate to consider sufficient the test for the analysis of CFR. For this reason, our main goal was to determine the velocity of coronary flow in each stage of dobutamine stress echocardiography and the heart rate value necessary to double the baseline values of coronary flow velocity in the territory of the left anterior descending (LAD) coronary artery.MethodsA total of 33 consecutive patients were analyzed. The patients included had low risk for coronary artery disease. All the participants underwent dobutamine stress echocardiography and coronary artery flow velocity was evaluated in the distal segment of LAD coronary artery using transthoracic color-Doppler echocardiography.ResultsThe feasibility of determining CFR in the territory of the LAD during dobutamine stress echocardiography was high: 31/33 patients (94%). Mean CFR was 2.67 at de end of dobutamine test.There was an excellent concordance between delta HR (difference between baseline HR and maximum HR) and the increase in the CFR (correlation coefficient 0.84). In this sense, we found that when HR increased by 50 beats, CFR was ≥ 2 (CI 93-99.2%). In addition, 96.4% of patients reached a CFR ≥ 2 (IC 91.1 - 99%) at 75% of their predicted maximum heart rate.ConclusionsWe found that the feasibility of dobutamine stress echocardiography to determine CFR in the territory of the LAD coronary artery was high. In this study, it was necessary to achieve a difference of 50 bpm from baseline HR or at least 75% of the maximum predicted heart rate to consider sufficient the test for the analysis of CFR.
Highlights
The determination of coronary flow reserve (CFR) is an essential concept at the moment of decisionmaking in ischemic heart disease
CFR measured by this test has been compared to CFR measured by adenosine stress echocardiography, and has been validated in comparative studies [11]
After reviewing the published literature, and as we did not find any parameter indicating when coronary flow reserve should be measured during dobutamine stress echocardiography, we decided to conduct out own investigation
Summary
The determination of coronary flow reserve (CFR) is an essential concept at the moment of decisionmaking in ischemic heart disease. Despite our wide experience with dobutamine stress echocardiography, we ignored the necessary heart rate to consider sufficient the test for the analysis of CFR For this reason, our main goal was to determine the velocity of coronary flow in each stage of dobutamine stress echocardiography and the heart rate value necessary to double the baseline values of coronary flow velocity in the territory of the left anterior descending (LAD) coronary artery. The valuable information provided by coronary angiography is not enough to study the functional status of atherosclerotic disease [2]. In these sense, several studies have demonstrated that management of coronary artery disease based on coronary artery anatomy without considering a. According to previous studies and to our personal experience, coronary flow velocity has a close relation with heart rate; we focused on analyzing coronary blood flow velocity and CFR in each stage of dobutamine stress echocardiography in order to determine: 1- The target HR for each patient to reach a CFR ≥ 2 (considered the adequate limit to rule out significant coronary stenosis in the territory of the LAD coronary artery by the international literature and our own experience) [11,12,13] and, with this information, to determine the delta HR and the percentage of maximum predicted heart rate that should be reached to make another determination of CFR. 2- The feasibility of the test
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