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Published on: November 24, 2014
Echocardiographic evaluation of internal mammary artery graft patency
Min-Ho Song1, Mamoru Ito, Sachie Toki
1Department of Cardiovascular Surgery, Nagoya Daini Red Cross Hospital, Nagoya, Japan. songmhmd@yahoo.co.jp
Insights
Transthoracic echocardiography accurately assesses internal mammary artery graft patency after bypass surgery. This noninvasive method, using diastolic velocity-time integral, reliably predicts graft function and can verify arterial graft patency.
Area of Science:
- Cardiovascular Surgery
- Diagnostic Imaging
- Vascular Ultrasound
Background:
- Internal mammary artery grafts are crucial for coronary artery bypass grafting (CABG) outcomes.
- Assessing graft patency noninvasively remains a clinical challenge.
- Early detection of graft dysfunction is vital for patient management.
Purpose of the Study:
- To evaluate the feasibility of transthoracic echocardiography (TTE) for assessing internal mammary artery (IMA) graft patency and function.
- To determine the correlation between echocardiographic parameters and coronary angiogram findings.
- To establish TTE as a reliable noninvasive method for IMA graft assessment.
Main Methods:
- Prospective study of 60 patients undergoing CABG from April 2000 to March 2002.
- Coronary angiography and Doppler TTE performed to assess IMA graft patency and flow.
- Measurement of flow velocity, velocity-time integral (VTI), and diastolic fraction of VTI.
- Stress testing utilized to evaluate dynamic changes in coronary flow via echocardiography.
Main Results:
- Overall IMA graft patency rate was 98%.
- Patent grafts exhibited a mean diastolic VTI of 0.64, increasing to 0.72 with stress.
- Occluded grafts consistently showed diastolic VTI fractions below 0.60.
- A statistically significant correlation was found between patency (FitzGibbon grade B or higher) and diastolic VTI > 0.60.
Conclusions:
- Doppler transthoracic echocardiography is a feasible and accurate method for assessing IMA graft patency.
- The diastolic velocity-time integral is a reliable echocardiographic predictor of IMA graft patency.
- TTE offers a valuable, noninvasive alternative for routine verification of arterial graft patency post-CABG.
Abstract:
The feasibility of using transthoracic echocardiography to assess internal mammary artery graft patency and function was examined. Coronary angiography and transthoracic echocardiography was performed in 60 consecutive patients undergoing coronary artery bypass from April 2000 to March 2002. Flow velocity, velocity-time integral, and the ratio of the diastolic fraction of the velocity-time integral to total velocity-time integral were measured by doppler transthoracic echocardiography. A stress test was carried out to detect coronary flow changes by echocardiography. The relationship between the coronary angiogram and the echocardiogram was analyzed. The overall graft patency rate was 98%. The mean diastolic velocity-time integral in patients with patent grafts was 0.64, and it increased up to 0.72 in response to physical stress. The occluded grafts showed diastolic velocity-time integral fractions of less than 0.60 in all grafts. There was a statistical correlation between patency > or = FitzGibbon grade B and diastolic velocity-time integral > 0.60. The diastolic velocity-time integral recorded by transthoracic echocardiography predicted the patency of internal mammary artery grafts. As echocardiography is noninvasive and accurate, it might be a useful method of verifying arterial graft patency.
