Noninvasive assessment of coronary flow reserve in the right gastroepiploic artery graft

Assessment of coronary flow velocity reserve by transthoracic Doppler echocardiography before and after coronary artery bypass grafting

Little is known about the changes in the coronary flow velocity reserve (CFVR) of the left anterior descending artery (LAD) before and after coronary artery bypass grafting (CABG). The present study aimed to evaluate the feasibility of measuring the CFVR of the LAD using transthoracic Doppler echocardiography before and after CABG. We prospectively measured the CFVR before and after CABG in 56 patients. The flow velocity in the LAD was measured using transthoracic Doppler echocardiography both at rest and during intravenous infusion of adenosine. The CFVR was calculated as the ratio of hyperemic to the basal peak and mean diastolic flow velocities. Coronary angiography was also performed to assess graft patency after CABG in all patients. Furthermore, we compared the differences between the pre- and postoperative CFVR in patients with and without a diffusely diseased LAD (lesion length >2 cm). All grafts were angiographically patent. The postoperative peak and mean CFVR were significantly increased compared to the preoperative peak and mean CFVR (both peak and mean 2.7 ± 0.9 vs 1.5 ± 0.6, respectively; p<0.0001). The preoperative peak CFVR was significantly lower in patients with a diffusely diseased LAD than in those without a diffusely diseased LAD (1.3 ± 0.5 vs 1.6 ± 0.5, respectively; p=0.04). The postoperative peak CFVR of the 2 groups was almost identical (2.5 ± 0.6 vs 2.9 ± 1.0; p=0.07). In conclusion, assessment of the CFVR of the LAD using transthoracic Doppler echocardiography was useful after CABG for confirming graft patency.

Flow capacity of gastroepiploic artery versus vein grafts for intermediate coronary artery stenosis

BACKGROUND

Native flow competition is a significant factor affecting bypass graft patency. The objective of this study was to compare the effect of competitive flow on conduit flow dynamics in the gastroepiploic artery (GEA) and the saphenous vein graft (SVG).

METHODS

In 51 patents, 23 GEAs (in-situ grafts) and 28 SVGs (aortocoronary grafts) were examined using a Doppler-tipped guidewire during coronary angiography after coronary artery bypass. Graft flow volume at rest and maximum graft flow volume during hyperemia were calculated from graft diameter and average peak velocity at rest and maximum average peak velocity induced by papaverine hydrochloride injection. Grafts were classified according to the grade of native coronary artery stenosis; group S (14 GEAs and 16 SVGs) displayed over 75% stenosis and group M (9 GEAs and 12 SVGs) exhibited over 50% up to 75% stenosis.

RESULTS

In group S, no difference in flow volume was apparent between the GEA and the SVG at rest (36+/- 17 vs 42 +/- 16) and during hyperemia (78 +/- 30 vs 88 +/- 28). In group M, flow volume of the GEA was significantly lower than that of the SVG at rest (17 +/- 11 vs 38 +/- 12; p = 0.029) and during hyperemia (32 +/- 19 vs 94 +/- 46; p = 0.001).

CONCLUSIONS

These data suggest that in intermediate coronary stenosis, GEA flow is compromised by native flow competition, whereas the SVG flow dynamics is maintained. However, the GEA can provide comparable flow capacity to the SVG and will achieve good surgical results when target coronary artery selection is appropriate.

Long-term follow-up of coronary artery bypass grafting in three-vessel disease using exclusively pedicled bilateral internal thoracic and right gastroepiploic arteries

BACKGROUND

Considerable data now exist that show that coronary artery bypass grafting with bilateral internal thoracic artery (ITA) grafts produce better outcomes than the use of a single ITA graft. The benefit of a third arterial graft has been less well established. Therefore this article describes the survival and cardiac-related event-free survival in patients having bilateral ITA and gastroepiploic artery (GEA) grafting for 3-vessel disease.

METHODS

From November 1992 to May 2002, 201 patients (mean age 53 +/- 7 years) presented with 3-vessel disease and received exclusively bilateral internal thoracic (ITAs) and right gastroepiploic (GEA) arteries as pedicled grafts for coronary artery bypass procedure. Twenty-seven (13%) patients were not elective, 10 (5%) were reoperations, 115 (57%) had one or more myocardial infarction, 21 (10%) had diabetes. In total 733 anastomoses were constructed (3.7/patient), with sequential grafting in 124 (62%) patients. The clinical follow-up was complete. The patients were followed for up to 10 years (mean 6.4 +/- 2.7 years).

RESULTS

Ten-year actuarial survival (including in-hospital death) was 87%. The actuarial freedom from angina pectoris, after hospital discharge, was 97% and 86% at 5 and 10 years respectively. None of the patients needed a repeat surgical revascularization after leaving the hospital, whereas 9 (5%) patients underwent a percutaneous transluminal coronary angioplasty. At 5 years 86% and at 10 years 69% of the patients remained free of any cardiac-related event.

CONCLUSIONS

The results of this study clearly indicate that the exclusive and extensive use of pedicled bilateral ITA and GEA in coronary bypass grafting provides excellent 10-year patient survival and functional improvement in terms of freedom from return of angina pectoris and, more impressive, freedom from any cardiac-related event. Our findings clearly corroborate the concomitant use of bilateral ITA and GEA grafts in selected patients with 3-vessel disease.

Assessment of flow velocity in a bypass graft of the gastroepiploic artery by contrast-enhanced transabdominal Doppler echocardiography: a case report

An 81-year-old man with effort angina pectoris underwent coronary artery bypass grafting operation using the bilateral internal thoracic arteries and the right gastroepiploic artery (GEA). Angiography after operation showed that the bilateral internal thoracic arteries were patent. Abdominal angiography showed severe ostial stenosis in the celiac trunk. The GEA was not opacified by the celiac trunk but by the superior mesenteric artery, by collaterals. GEA flow could be detected from the epigastric lesion by contrast-enhanced Doppler echocardiography, and moreover, the flow velocity reserve of the graft was 2.4. This case suggests that the GEA graft can provide sufficient blood flow to the coronary artery despite ostial stenosis of the celiac trunk.

Noninvasive assessment of flow velocity and flow velocity reserve in the right gastroepiploic artery graft by transcutaneous Doppler echocardiography: comparison with an invasive technique

BACKGROUND

The measurement of flow velocity (FV) in coronary artery bypass grafts using a Doppler guidewire has provided useful clinical and physiologic information. The recently developed transcutaneous Doppler echocardiography is a noninvasive technique to measure FV and FV reserve (FVR) in the right gastroepiploic artery (GEA) graft. The purpose of this study was to evaluate whether transcutaneous Doppler echocardiography accurately measures FV and FVR in the right GEA graft in a clinical setting.

METHODS

In 33 patients who underwent graft angiography for the assessment of the right GEA graft, FV in the right GEA graft was measured by transcutaneous Doppler echocardiography under the guidance of color flow Doppler imaging at the time of examination using a Doppler guidewire. FV in the midportion of the right GEA graft was measured at baseline and during hyperemic conditions using both transcutaneous Doppler echocardiography and a Doppler guidewire.

RESULTS

There were excellent correlations between the value of FV obtained by transcutaneous Doppler echocardiography and those obtained with the Doppler guidewire (averaged peak velocity: y = 0.95 x + 1.46, r = 0.98, standard error of the estimate [SEE] = 2.94 cm/s; averaged systolic peak velocity: y = 0.94 x + 1.18, r = 0.97, SEE = 3.15 cm/s; diastolic peak velocity: y = 0.97 x + 1.62, r = 0.98, SEE = 4.40 cm/s; averaged diastolic peak velocity: y = 0.95 x + 1.75, r = 0.98, SEE = 3.60 cm/s). The FVR as determined by transcutaneous Doppler echocardiography showed a good correlation with that determined using the Doppler guidewire method (y = 0.90 x + 0.21, r = 0.92, SEE = 0.31).

CONCLUSIONS

Transcutaneous Doppler echocardiography proved to be an accurate noninvasive method to measure FV and FVR in the right GEA graft.