[The Doppler color detection of internal mammary artery anastomoses and a functional assessment of their patency]

Noninvasive Dynamic Assessment With Transthoracic Echocardiography of a Composite Arterial Y-Graft Achieving Complete Myocardial Revascularization

BACKGROUND

Composite arterial grafts are increasingly used in coronary artery bypass surgery. We assessed with transthoracic echocardiography the composite radial artery and in situ left internal thoracic artery Y-graft.

METHODS

In 53 of 60 consecutive patients who underwent complete myocardial revascularization using only this composite arterial graft, good transthoracic echocardiographic images and pulsed Doppler signals of the Y-graft main stem were obtained at rest and early after standard exercise. Stress/rest 99mTc-sestamibi myocardial perfusion single-photon emission computed tomography (SPECT) was the gold standard for residual myocardial ischemia. The patients with negative SPECT were divided into groups according to the number of coronary artery systems grafted, and history of preoperative myocardial infarction.

RESULTS

Diastolic peak velocity, diastolic velocity-time integral, the diastolic-to-systolic ratio of the peak velocities and velocity-time integrals, and the stress-to-rest ratio of the diastolic peak velocities and diastolic velocity-time integrals in the negative-SPECT patients were significantly greater than in the 6 positive-SPECT patients. Sensitivity and specificity for ischemia of the stress-to-rest ratio of the diastolic peak velocities less than 1.5 were 100%. The stress-to-rest ratio of the diastolic velocity-time integrals in the patients with three coronary systems grafted, and in those without preoperative myocardial infarction, were respectively greater than in the patients with two systems grafted (p < 0.0001), and in those with preoperative myocardial infarction (p = 0.0048).

CONCLUSIONS

Noninvasive dynamic assessment with transthoracic echocardiography of a composite arterial graft, including in situ left internal thoracic artery, is feasible and correlates with myocardial perfusion SPECT. The Y-graft used was able to regulate its flow capacity to myocardial demand.

Color Doppler ultrasonography for evaluation of internal mammary artery application in adolescent female patients with right-convex thoracic idiopathic scoliosis

STUDY DESIGN

Prospective comparative study.

OBJECTIVE

To establish the use of Color Doppler Ultrasonography to investigate internal mammary artery.

SUMMARY OF BACKGROUND DATA

Breast asymmetry in female adolescents with right convex idiopathic scoliosis was supposed to be linked with anatomic and functional asymmetry of the internal mammary artery that is the main supplier to the mammary gland. However, no measurements of anatomic and hemodynamic parameters of internal mammary artery have been made to justify or to reject the hypothesis of asymmetric blood flow volume to the breasts and costosternal junction in female adolescent scoliotics. Color Doppler Ultrasonography is a well established noninvasive method to assess vessel anatomy and hemodynamics.

METHODS

Twenty female adolescents with right thoracic scoliosis and 16 comparable female individuals without spine deformity were examined with Color Doppler Ultrasonography to measure at the origin of internal mammary artery lumen diameter, cross sectional area, time average mean flow and flow volume per minute and were compared each other.

RESULTS

The reliability of Color Doppler Ultrasonography was high and the intraobserver variability low (ANOVA, P = 0.92-0.94). There was no statistically significant difference in the ultrasonographic parameters of the internal mammary artery between right and left side in each individual as well as between scoliotics and controls.

CONCLUSIONS

Color Doppler Ultrasonography applied to assess anatomic or hemodynamic blood flow parameters at the origin of internal mammary artery was proven a highly reliable method. Color Doppler Ultrasonography disclosed no side-differences, while there were no differences between scoliotics and controls. Thus, it seems that this study cannot justify previous theories for development of right thoracic scoliosis in female adolescents.

[Patency study of internal mammary artery grafts: the usefulness of echo-enhancers for identifying the flow signal by color Doppler echocardiography]

OBJECTIVES

a) To study the capacity of the technique of high-frequency color Doppler to detect flow signal of left internal mammary artery grafts; b) to assess the usefulness of an echo-enhancer agent to facilitate the detection of the signal, and c) to evaluate the patency of the graft according to its pulsed Doppler velocity profile pattern.

METHODS

39 consecutive patients were studied. A Hewlett-Packard 5500 echocardiograph was used, with a high-frequency probe (S12) applied at the high left parasternal border. When a graft signal was not elicited after a predetermined 5-minute check period, an intravenous dose of 4 g of Levovist (Schering España) at 400 mg/ml was administrated. According to previous studies, a pulsed Doppler flow profile with a predominantly diastolic pattern was considered a normal graft patency, while a systolic one was deemed as abnormal.

RESULTS

Graft flow was identified by color Doppler in 33/39 patients (85%). The additional use of an echo-enhancer in 6 patients with no detected signal increased this proportion to 38/39 (97%). Normal flow patterns were seen in 34/38 (89%). Among the four patients with abnormal pattern, 1 case of early myocardial infarction was observed, while angiographic studies showed distal occlusion of the graft in 1 or the presence of competitive flow in 2 patients.

CONCLUSIONS

The high-frequency color Doppler technique allows the detection of a flow signal from internal mammary artery grafts in most patients. The administration of an echo-enhancer agent is useful in those with non detectable signals. An abnormal pulsed Doppler velocity pattern indicates graft malfunction.