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Transesophageal assessment of coronary flow velocity reserve during "regular" and "high"-dose dipyridamole stress
S J Hutchinson1, A Shen, S Soldo
1Division of Cardiology, Department of Medicine, Los Angeles County/University of Southern California Medical Center, Los Angeles, California, USA.
Insights
Coronary flow velocity reserve (CFVR) assessed with dipyridamole stress testing is more sensitive for detecting coronary artery disease than echocardiography alone. Higher dipyridamole doses improve sensitivity for ischemia detection.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Pharmacology
Background:
- Dipyridamole is a common pharmacologic stress agent used in non-invasive cardiac diagnostics.
- Assessing coronary flow velocity reserve (CFVR) offers a direct measure of myocardial perfusion.
- Standard echocardiographic criteria can sometimes underestimate the extent of coronary artery disease.
Purpose of the Study:
- To evaluate the impact of regular and high-dose dipyridamole on left anterior descending artery (LAD) flow velocity.
- To compare the sensitivity of CFVR versus standard echocardiographic criteria for detecting myocardial ischemia.
- To determine optimal dipyridamole dosing for different stress testing endpoints.
Main Methods:
- Prospective study of 47 patients with varying degrees of LAD stenosis.
- Transesophageal echocardiography to assess LAD flow velocity and wall motion at baseline and hyperemia.
- Administration of dipyridamole at 0.56 mg/kg and 0.84 mg/kg doses.
Main Results:
- CFVR was significantly more sensitive (88%) than wall motion monitoring (44-75%) for detecting coronary obstruction.
- A CFVR <2.3 threshold demonstrated high sensitivity for identifying coronary artery disease.
- Combining CFVR and wall motion monitoring yielded the highest sensitivity (94%) for ischemia detection.
Conclusions:
- Dipyridamole-induced CFVR assessment is a sensitive tool for diagnosing coronary artery disease.
- The 0.56 mg/kg dipyridamole dose is adequate for flow response assessment, while 0.84 mg/kg is more sensitive for ischemia detection.
- Integrating CFVR with echocardiographic wall motion analysis enhances diagnostic accuracy for coronary artery disease.
Abstract:
To assess the effect of regular and high-dose dipyridamole on coronary flow velocity in the left anterior descending artery (LAD), and to determine whether assessment of coronary flow velocity reserve (CFVR) is more sensitive for detection of ischemia than standard echocardiographic criteria, 47 patients were studied prospectively: 16 patients with stenosis of the LAD, 18 patients with angiographically normal LADs, and 13 patients with minimal disease. Patients underwent transesophageal echocardiographic study of wall motion and LAD flow velocity at baseline and at hyperemia, and for angina and electrocardiographic changes. The mean CFVR values after 0.56 mg/kg after 0.84 mg/kg of dipyridamole were similar: 2.52 +/- 0.87 versus 2.62 +/- 0.90. A CFVR <2.3 (normals mean -2 SDs) was more sensitive (88% at both doses) for the detection of underlying coronary obstruction than was wall motion monitoring (44% and 75%, respectively). The combination of CFVR <2.3 and wall monitoring was more sensitive than index alone (94% at both 0.56 and 0.84 mg/kg). The rate-pressure product was not significantly different at the two doses of dipyridamole. When flow response is the end point of stress testing, as with transesophageal monitoring, the 0.56 mg/kg dose of dipyrid mole is adequate, but when ischemia is the end point (as with wall motion monitoring by 2-dimensional echocardiography), the dose of 0.84 mg/kg is more sensitive.