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Preserved hyperaemic response in (distal) string sign left internal mammary artery grafts
Joost Hartman1, Hans Kelder, Rob Ackerstaff
1Department of Cardiothoracic Surgery, Thoraxcentre, Bd 575, Erasmus Medical Centre Rotterdam, PO Box 2040, 3000 CA Rotterdam, The Netherlands.
Insights
Supraclavicular ultrasonography effectively assesses left internal mammary artery (LIMA) to left anterior descending (LAD) grafts. This method identifies
Area of Science:
- Cardiovascular Surgery
- Medical Imaging
- Vascular Ultrasound
Background:
- The left internal mammary artery (LIMA) to left anterior descending (LAD) artery graft is a critical component of coronary artery bypass grafting.
- Assessing graft patency and function postoperatively is essential for patient outcomes.
- The 'string sign' on angiography indicates potential graft compromise.
Purpose of the Study:
- To evaluate the correlation between supraclavicular ultrasonography findings at rest and during hyperemia with angiographic results of LIMA-LAD grafts.
- To determine if ultrasonography can differentiate between patent grafts and those with the 'string sign'.
- To assess the functional status of LIMA-LAD grafts using Doppler ultrasonography.
Main Methods:
- Prospective study of 53 patients with LIMA-LAD grafts.
- Postoperative arteriography performed at an average of 1.4 years.
- Supraclavicular ultrasonography (rest, hyperemia, post-hyperemia) performed at an average of 1.8 years, analyzing peak velocities and velocity integrals.
Main Results:
- Ultrasonography correlated significantly with arteriographic findings (p<0.013).
- All graft types showed increased velocities during hyperemia (p<0.018).
- The 'string sign' was identified in 17.3% of grafts, with a characteristic flow profile.
Conclusions:
- Supraclavicular ultrasonography is a valuable tool for assessing LIMA-LAD graft patency and function.
- The 'string sign' grafts demonstrate recruitable flow, indicating potential functionality.
- Ultrasonography can identify functional graft status in relation to myocardial oxygen demand.
Objective:
To correlate supraclavicular ultrasonography at rest and in hyperaemic response with angiographically patent and (distal) 'string sign' left internal mammary artery (LIMA) to left anterior descending (LAD) area grafts.
Methods:
Fifty-three patients with LIMA to LAD area grafting were prospectively entered in a follow-up study. Arteriography (native and LIMA) was performed at 1.4+/-0.8 years postoperatively and ultrasonography was performed at rest, in hyperaemic response and 2min after hyperaemic response at 1.8+/-0.8 years postoperatively and was compared to arteriography. Ultrasonographic parameters analysed were systolic and diastolic peak velocity, systolic and diastolic velocity integral, diastolic/systolic peak velocity ratio and diastolic/total velocity integral ratio.
Results:
One patient was excluded because obesity hampered ultrasonography. Arteriography demonstrated functional grafts in 43 patients (group I), sequential distal 'string sign grafts' in 4 patients (group II) and total 'string sign grafts' in 5 patients (group III). Between the groups all ultrasonographic velocities showed a significant linear relation (p
Conclusions:
String sign LIMA grafts' were found in 9/52 (17.3%) patients. All patent and all 'string sign grafts' showed a shift towards a coronary flow profile in the proximal segment postoperatively. The study revealed the 'functionality' of the patent and the (distal) 'string sign LIMA graft' in regard to myocardial oxygen demand. 'String sign grafts' are 'recruitable' on demand.
