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With time we seem to be increasingly encountering degenerated Saphenous Vein Grafts (SVG) in contemporary interventional cardiology practice. Established clinical guidelines recommend the routine use of Distal Protection Devices (DPD) to mitigate the occurrence of slow/no flow which sometimes makes the procedure complex and cumbersome. This series highlights how information from IVUS interrogation of SVG grafts have resulted in reduced dependence on DPDs and refined PCI strategy.
Over a period of 2 years (2013-2015), we evaluated 8 post-CABG patients with exertional angina who underwent conventional coronary angiograms and revealed variable degrees of bypass graft degeneration requiring repeat coronary intervention. Baseline demographic is shown in table 1 below. Based on our experience with IVUS, fibrotic lesions in vein grafts have been routinely treated with serial graded aggressive high-pressure balloon dilatations for optimal bed preparation prior to stent deployment. In all these patients' distal protection device was not used. Outcomes in the form of slow flow/no flow, stent under-deployment, dissection, perforation, periprocedural myocardial infarction, stroke and 30-day mortality were assessed in all these patients.
In this series, we intervened in a total of 11 SVG grafts. Most of the 11 SVG grafts showed tight fibrotic lesions located proximally, which initially did not yield to small diameter non-compliant balloons with high-pressure balloon dilatations, but gradually yielded to high pressure (20-24 atm) balloon dilatations with 3 to 3.5 NC balloons. Adequate bed preparation resulted in optimal stent (mean diameters of 3.8 mm) deployment with minimal residual stenosis. We stented 10 grafts. We did not stent one graft as the bed preparation was inadequate (Fig 1) and in another, we were unable to post dilate the stent despite using non-compliant balloons at high pressures (Fig 2). Accompanying IVUS images have been provided in both these cases. All the 8 patients underwent PCI without the use of any distal protection device. Despite not using DPD there was no slow flow/no flow.
In our series of 11 SVG grafts, we encountered severe difficulty in our first two grafts where we could not adequately post dilate one stented graft and failed to adequately predilate another graft in the same patient. Both these grafts had proximally situated disease and IVUS studies revealed both stenoses to be heavily fibrotic in nature. Based on this experience we employed caution in our subsequent cases, especially where the lesions were located proximally and found that this stenosis required graded balloon dilatations going up to very high pressures of 20-24 atmospheres before giving way. This enabled us to optimally deploy stents in these segments with no slow/no flow. We did not use DPD in any of these patients. Our illustrative examples show that these fibrotic lesions can be located proximally and can extend to the mid segment in a long tubular fashion with the whole graft behaving in a manner that can only suggest extensive fibrosis. We recommend the use of IVUS to interrogate such vein grafts prior to deciding optimal PCI strategy.