Transthoracic Doppler echocardiography of mammary artery grafts to assess graft function.
BACKGROUND
Transthoracic Doppler echocardiography of internal mammary artery grafts (MAGs) has been tested by the supraclavicular approach, but little information is available about the parasternal approach.


OBJECTIVE
To evaluate the usefulness of parasternal transthoracic Doppler echocardiography to assess the patency of left and right MAGs.


METHODS
Forty-eight patients with previous MAGs were divided into two groups on the basis of coronary angiography: 42 patients had patent MAGs and six patients had severe MAG stenosis. Doppler echocardiography of MAGs was performed on all patients, both at baseline and after low-dose dipyridamole infusion. Systolic and diastolic time-velocity integrals and their ratios were obtained, and MAG flow reserve was calculated.


RESULTS
Patients with patent MAGs had a predominant diastolic flow, while a prominent systolic pattern was found in the presence of MAG stenosis. In patients with stenosis, baseline Doppler analysis showed a lower diastolic peak velocity (DPV) (P<0.01), diastolic time-velocity integral (P<0.05), and diastolic and systolic time-velocity integral ratios (both P<0.005), and a reduced MAG flow reserve (P<0.001). In the overall population, when adjusting for clinical variables, a multilinear regression analyis underscored MAG flow reserve (beta=0.38, P<0.01) and baseline DPV (beta=0.29, P<0.05) as independent determinants of MAG stenosis (cumulative R2=0.25, P<0.005).


CONCLUSIONS
Doppler echocardiographic evaluation of MAGs is a reliable, noninvasive tool to assess MAG patency and functional status of the vessel. MAG blood flow reserve and baseline DPV are independent determinants of MAG stenosis.
Cicala
Silvana
S
Department of Cardiothoracic and Respiratory Sciences, Second University of Naples, Monaldi Hospital, Naples, Italy.
Renzulli
Attilio
A
Galderisi
Maurizio
M
De Simone
Luigi
L
De Feo
Marisa
M
Onorati
Francesco
F
Cerasuolo
Flavio
F
Bonzani
Giulio
G
Caso
Pio
P
Cotrufo
Maurizio
M
D000368:Aged; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods*; D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000601:surgery*; D018618:Echocardiography, Doppler, Color; D017548:Echocardiography, Transesophageal; D005260:Female; D006084:Graft Rejection; D006085:Graft Survival; D006801:Humans; D007387:Internal Mammary-Coronary Artery Anastomosis; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000379:methods; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011336:Probability; D011379:Prognosis; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D014654:Vascular Patency