The radiologic evaluation of patients with coronary bypass

Impact of saphenous vein graft radiographic markers on clinical events and angiographic parameters

BACKGROUND

Use of saphenous vein graft (SVG) radiographic markers has been associated with shorter cardiac catheterization procedure times and reduced contrast agent volume for postoperative coronary artery bypass graft (CABG) catheterizations. Use of such markers is varied and often operator-dependent, as the effect of SVG markers has not been fully evaluated. The goal of the present analysis was to evaluate the association of SVG markers with clinical outcomes and graft patency.

METHODS

Data were drawn from the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV trial of patients undergoing CABG at 107 hospitals across the United States. Repeat angiography was performed within 12 to 18 months after CABG. The SVG markers were used at the discretion of the surgeon and were identified on the follow-up angiogram as any device used to mark the ostium, regardless of shape.

RESULTS

The SVG markers were present in 51.2% of evaluable patients (910 of 1,778) and 52.3% of SVGs (2,228 of 4,240). Among patients with totally occluded SVGs (n = 911), visual identification of the SVG was obtained more frequently in those with an SVG marker (90.7% vs 72.1%, p < 0.001). The SVG stenosis 70% or greater at follow-up did not differ by use of markers (25.8% with marker vs 24.4% without marker, p = not significant). These findings were also consistent in ostial lesions (n = 942). Long-term death or myocardial infarction (MI) was similar by use of marker. The perioperative CABG MI was higher in patients with SVG markers (10.1% vs 5.5%, odds ratio adjusted 1.86, p = 0.021).

CONCLUSIONS

Saphenous vein graft radiographic markers were associated with higher rates of direct visualization of totally occluded SVGs without an adverse effect on graft patency or long-term clinical outcomes, but the association of SVG markers with increased perioperative CABG MI warrants further examination.

Long-term serial angiographic studies after coronary artery bypass surgery

Twenty-six patients underwent repeat coronary angiography 5--8 years after saphenous vein coronary artery bypass surgery (SVCABG). These patients were selected from the first cohort of 117 patient who had SVCABG because they had obtained essentially complete relief of angina, and because all grafts were patent at initial angiography 11.2 months (mean) after surgery. Of the 39 grafts (1.5 grafts per patient) patent at 1 year, 34 (87.2%) were patent at reexamination 76 months (mean) (range 65--103 months) after SVCABG. Graft occlusion could not be predicted by the early angiographic appearance of the graft itself or its proximal or distal anastomosis. In some cases, narrowing or irregularity consistent with intimal hyperplasia appeared to progress, while in others it developed at late follow-up. Progressive narrowing occurred in 96% (22 of 23 grafted vessels) of the native coronary arteries proximal to the graft anastomosis. Progresssion to a stenosis greater than 75% or total occlusion was seen distal to the graft anastomosis in eight of 39 grafts (20%). Of 103 non-bypassed major vessels, 56% showed some progression of disease and half of these progressed to significant stenoses (greater than 75% luminal narrowing). There were no apparent predictors to indicate whether progression in nongrafted coronary arteries would occur preferentially in a previously stenotic or nonstenotic vessel, although 80% of vessels with initial stenoses greater than 75% progressed to total occlusion.