Abstract
We present two cases with chronic total occlusion of the saphenous vein graft in two patients with a history of previous bypass surgery with unfavorable anatomic features for recanalization of the native coronary artery. In the first case, two dedicated attempts for recanalization of chronic total occlusion of the native artery failed and in the second case there was not an adequate visualization of the native vessel beyond the occlusion point, not even by contralateral injection. Excimer laser atherectomy was used in both cases as an adjuvant therapy during recanalization of the saphenous vein graft in combination with a distal protection device in order to reduce distal embolization. The procedures proved successful after stent implantation in the whole length of the saphenous vein grafts and the patients suffered no remarkable events during hospitalization.
Highlights
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Percutaneous coronary intervention of chronically occluded saphenous vein graft in cases with unfavorable anatomic features of native coronary artery.
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Use of excimer laser atherectomy as adjuvant therapy in order to reduce distal debris embolization.
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Simultaneous use of distal protection device in combination with laser coronary to increase the safety of the procedure.
1
Introduction
Excimer laser coronary atherectomy (ELCA) consists of the application of electromagnetic energy with the capability of debulking atherosclerotic plaques in different kinds of lesions . The first generation of cardiac laser used continuous wave and subsequently generated tissue temperature higher than 160 °C, resulting in significant damage to the coronary wall as a consequence . The new generation of cardiac laser utilizes pulse-wave modality combining brief pulse duration alternated with long pause interval, which prevents adverse effects driven from thermal injury on the vascular wall .
ELCA is potentially effective for the percutaneous treatment of a variety of complex lesions including chronic total occlusion (CTO), calcified lesions, stents restenosis, balloon-crossing failures, thrombus vaporization in acute coronary syndrome and eventually saphenous vein graft (SVG) debulking . Percutaneous coronary intervention (PCI) of an SVG in the setting of acute coronary syndrome is technically feasible although attention should be paid to distal embolization due to high thrombus burden. In the case of SVG chronically occluded the recommended strategy is to recanalize the native artery if technically possible. In the event that the recanalization of the occluded native artery is not possible and the patient’s symptoms persist, a PCI over SVG can be reserved as a last option. The two cases presented here both have unfavorable anatomic features for PCI of the CTO native artery. The use of dedicated techniques for CTO-PCI combined with an adjuvant debulking device such as ELCA for recanalization of a totally occluded SVG makes the procedures technically interesting and challenging.
1.1
Case 1
A 67-year-old man was admitted to our hospital due to a non-ST elevation acute coronary syndrome (NSTEACS). Coronary risk factors were a smoking habit, hypertension and dyslipidemia. The patient suffered from chronic kidney disease and was undertaking a hemodialysis program. One year before the last coronary event he was diagnosed with a type-B aortic dissection below the left subclavian artery which was conservatively managed. From a cardiologic point of view, the patient had a history of chronic ischemic cardiomyopathy and he was operated with a coronary artery bypass graft (CABG) in 1988 with left internal mammary artery (LIMA) to left anterior descending artery (LAD), and SVG to first obtuse marginal (OM) and to right coronary artery (RCA). In January 2015, the patient presented with NSTEACS and underwent a coronary angiogram which showed all three bypasses patent. In September and December 2015, he presented two consecutive NSTEACS and both were conservatively managed. The current episode happened in June 2016, six months after the last coronary event and on this occasion the patient presented a troponin I elevation up to 14 ng/ml. A coronary angiogram revealed total occlusion of SVG supplying OM from the ostial segment. The native artery was totally occluded without adequate collateralization to its distal bed ( Fig. 1 ). SVG to RCA and LIMA to LAD both were patent. There was no Q wave in the electrocardiogram registry and an echocardiographic examination showed hypokinetic motion in the inferolateral wall with a normal left ventricular ejection fraction. As the patient presented with recurrent chest pain and taking into account the unfavorable anatomic features for PCI to the native OM, an angioplasty on the SVG was planned.
The procedure was performed by radial approach using a long sheath introducer (90 cm) and a 6F AL2 guiding catheter for a proper SVG engagement, occluded from the ostial segment ( Fig. 2 ; Video 1 ). The angiogram of the previous patent SVG was used during the procedure for the step-by-step advancement of the guidewires. With a Pilot 50 guidewire through a Finecross microcatheter (Terumo medical corporation, Japan) we were able to traverse the proximal segment of the SVG and afterwards a Pilot 200 was used to advance up to the native vessel. After blood aspiration, a cautious dye injection through the microcatheter confirmed the true lumen position ( Fig. 3 ; Video 2 ).
In this step, an ELCA 0.9 mm catheter (Spectranetics, Colorado Springs, Co.) was used at 25 mJ/mm 2 (fluences) and pulse repetition rates (frequency) of 40 Hz throughout the entire SVG ( Figs. 4 and 5 ) with the patient’s tolerance. After positioning an embolization protection device Spider FX 3 mm (ev3 Inc. Plymouth, MN, USA) in the distal part of the SVG, predilatation with 2.5 × 25 mm balloon at low atmosphere was performed ( Fig. 6 ). Three drug eluting stents (DESs), Xience 3 × 48 mm (Abbott Vascular, Santa Clara, USA), CRE 8: 3 × 46 mm (CID, Alvimedica; Saluggia VC, Italy) and Xience 3 × 23 mm were successfully implanted although a significant residual lesion in the distal segment persisted ( Fig. 7 ). Two additional DESs (Onyx: 3 × 18 mm and Onyx: 3 × 38 mm (Medtronic, Inc. MN, USA)) were implanted without a distal protection device in the SVG distal segment achieving an excellent angiographic final result ( Fig. 8 ; Video 3 ). Troponin determination after the procedure did not show any re-elevation and the patient was discharged without any remarkable events during hospitalization.
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