Asian Cardiovasc Thorac Ann 2006;14:155-157
© 2006 Asia Publishing EXchange Ltd
A Technical Failure Changes a Y-graft into a C-conduit Causing Steal Syndrome
Sharif Al-Ruzzeh, PhD,
Mahmoud Bustami, MRCP,
Thanos Athanasiou, PhD,
Shane George, FRCA,
Charles Ilsley, FRCP,
Mohamed Amrani, PhD
The National Heart and Lung Institute, Imperial College of Science, Technology and Medicine, Harefield Hospital, Middlesex, United Kingdom
For reprint information contact: Sharif Al-Ruzzeh, PhD Tel: 44 796 802 5332 Fax: 44 148 288 1657 Email: sharifalruzzeh{at}hotmail.com, 18 Fielding Way, Leeds LS27 9AB, United Kingdom.
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ABSTRACT
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Y-grafting is a common coronary grafting technique for performing composite coronary grafts. The outcome and efficacy of this technique have not been studied in detail in the literature. We report a case of an occlusion in the proximal limb of a Y-graft, changing it into a C-shaped conduit and causing a steal syndrome. Our aim is to raise the level of caution when performing this type of composite graft and to suggest how this complication can be managed postoperatively.
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CASE HISTORY
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An 80-year-old woman was admitted for an elective triple-vessel coronary artery bypass grafting (CABG). She had suffered a myocardial infarction (MI), for which she was treated by immediate thrombolysis, 13 months before the date of the operation, and was complaining of grade IV chronic stable angina and grade II dyspnea. Angiographic examination showed triple-vessel disease comprising of 70% left anterior descending (LAD) artery stenosis, 80% circumflex artery (Cx) stenosis and a completely (100%) occluded right coronary artery (RCA) (Figure 1
). Left ventricular angiography revealed an overall good function, apart from a localised area of hypokinesia inferiorly, with an overall estimated ejection fraction of 56%. Other co-morbidities included hypertension for 15 years, chronic stable asthma controlled by inhalers for 50 years and hypercholesterolemia.
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Figure 1. Preoperative angiogram showing the left anterior descending (LAD) artery and the first obtuse marginal (OM) artery.
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The patient underwent triple off-pump CABG with the left internal thoracic artery (LITA) grafted to the LAD, the saphenous vein (SV) graft anastomosed to the first obtuse marginal artery (OM) and the radial artery (RA) graft anastomosed as a Y-graft off-SV to the posterior descending artery (PDA). The procedure was well tolerated and the patient had an uneventful postoperative recovery in hospital. The patient was ventilated for 5.5 hours, and subsequently remained for 12 hours in the intensive therapy unit (ITU) and 7 days in hospital.
At the routine 6-week follow-up visit to the clinic, the patient complained of unstable angina at rest, which was limiting her physical activity to a major extent. Electrocardiogram showed new ST depression and T wave inversion changes in the lateral chest leads V4–V6. Angiographic examination revealed a patent and fully functioning LITA graft to the LAD, which was accompanied by a relative improvement in left ventricular function. The overall ejection fraction was estimated to be 68%, compared to 56% in the preoperative angiogram. Whilst the proximal limb of the Y-graft was blocked proximal to the level of the anastomosis, the rest of the SV graft and the whole of the RA graft were both patent with excellent flow. This manifested as formation of a C-shaped conduit, causing a "steal syndrome" from the OM to the RCA/PDA, which was totally occluded (Figure 2).
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Figure 2. Postoperative angiogram showing the C-shaped conduit formed from the distal part of the saphenous vein (SV) graft anastomosed to the first obtuse marginal (OM) artery, and the complete radial artery (RA) graft anastomosed to the posterior descending artery (PDA). The site of the Y-anastomosis is indicated on the figure.
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The decision was made by the cardiologist, with patient consent, to stent the left main stem into the Cx artery in an attempt to ameliorate the symptoms without surgical revision of the CABG procedure. The stenotic segment was pre-dilated with a 3 x 20 mm balloon before the deployment of 3 x 18 mm AVE-S7 (Medtronic, Minneapolis, USA) stent at 12 atmospheres. A post-stent deployment shot confirmed improved native flow into the native Cx artery and via the C-shaped conduit into the native PDA (Figure 3). The patient developed no complications subsequent to the procedure and was reviewed at follow-up clinics at 2, 6, 12 and 24 weeks without reporting any angina or dyspnea. The patient remained stable without requiring any anti-anginal medication.
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Figure 3. Post-stent deployment view showing the stented segment of the proximal part of the circumflex (Cx) artery with a functioning C-shaped conduit.
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DISCUSSION
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This reported case shows that the construction of a composite Y-graft can be complicated by obstruction of the proximal limb. The resultant C-shaped conduit causes a steal syndrome that can give rise to ischemic symptoms post-CABG. Obstruction of the proximal limb occurred early, indicating predominance of a technical failure of the proximal anastomosis rather than failure of the grafting strategy in constructing the Y-graft. However, as a self-criticism, we probably should have avoided anastomosing the RA to SV and simply constructed the Y-graft from two SV conduits.
Any composite coronary surgical grafting technique requires a very high level of surgical skill. In our case, even though the Y-graft was performed by a senior surgeon and on relatively tight target native coronary arteries, 80% and 100% stenosed, the graft failed in its proximal section. However, the two distal limbs remained patent and functioning causing this unexpected early complication.
The outcome of this technique has not been adequately assessed in the literature due to the fact that several factors can affect graft patency, and failures tend to be under-reported. It is still controversial whether the composite Y-graft provides sufficient blood flow to the myocardial regions targeted by its two distal limbs. It has already been shown that although the Y-grafting technique improved the regional myocardial blood flow (MBF) at rest, it was not as effective as independent single grafts in maintaining or improving coronary flow reserve (CFR) in a study conducted on gold-standard LITA-LAD grafts.1 Several explanations have been postulated for this occasionally-observed under-performance of the composite grafts in general, and it appears that flow competition is the most widely accepted.2 Furthermore, it has also been suggested that flow rates in the Y-grafts are probably more dependent on the severity of obstruction in the grafted native coronary arteries rather than the type of conduits chosen for creating the Y-graft.3 On the other hand, the Y-grafting technique provided excellent clinical and angiographic outcomes4 and reduced neuropsychological dysfunction.5
In conclusion, Y-grafting, and generally composite grafting requires a high level of caution and skill in order to avoid complications arising from unexpected flow dynamics.
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REFERENCES
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- Sakaguchi G, Tadamura E, Ohnaka M, Tambara K, Nishimura K, Komeda M. Composite arterial Y graft has less coronary flow reserve than independent grafts. Ann Thorac Surg 2002;74:493–6.[Abstract/Free Full Text]
- Amano A, Takahashi A, Hirose H. Skeletonized radial artery grafting: improved angiographic results. Ann Thorac Surg 2002;73:1880–7.[Abstract/Free Full Text]
- Al-Attar N. Coronary flow reserve in composite arterial Y grafts. Ann Thorac Surg 2003; 76:659–60.[Free Full Text]
- Calafiore AM, Contini M, Vitolla G, Di Mauro M, Mazzei V, Teodori G, et al. Bilateral internal thoracic artery grafting: long-term clinical and angiographic results of in situ versus Y grafts. J Thorac Cardiovasc Surg 2000;120:990–6.[Abstract/Free Full Text]
- Royse AG, Royse CF, Ajani AE, Symes E, Maruff P, Karagiannis S, et al. Reduced neuropsychological dysfunction using epiaortic echocardiography and the exclusive Y graft. Ann Thorac Surg 2000; 69:1431–8.[Abstract/Free Full Text]
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