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J Thorac Cardiovasc Surg 2008;136:1604-1606
© 2008 The American Association for Thoracic Surgery
Letter to the Editor |
Department of Cardiothoracic Surgery, Stanford University Medical School, Stanford, Calif
We thank Della Corte and Cotrufo from Naples for their interest in our observations and for raising several critical points concerning the "aortopathy" associated with bicuspid aortic valve (BAV) disease. Owing to space limitations, we can only discuss the important question of extent of aortic resection at the time of operation, particularly in light of the recent condemnation of the more aggressive American College of Cardiology/American Heart Association guidelines by Guntheroth.1
Primum non nocere. We agree with this principle and uphold it in our clinical practice. On all too numerous occasions we have surgically treated BAV patients who have undergone previous aortic valve replacement (AVR) with or without ascending aortic replacement who present with a large aortic arch aneurysm, pseudoaneurysm, or dissection, sometimes annealed to the posterior table of the sternum, which can mandate cooling and circulatory arrest before completing the redo sternotomy. These are challenging redo cases in the best of hands. The situation might possibly have been avoided if more complete resection of the dilated aorta at the time of initial procedure had been carried out. Della Corte and Cotrufo over the years have done a superb job describing the various histologic and pathologic characterizations of the aorta of patients with a BAV and have highlighted that a diseased aorta does not suddenly happen at the magical 5.0-cm mark. The 5.0-cm threshold is just an arbitrary diameter at which surgical results in average medical centers are projected to be superior to the natural history of the disease. But here, as always, is the rub: Guidelines are easy to apply to medical therapy, but application of guidelines to different surgeons who have variable degrees of experience with a given procedure and substantially different operative results may yield suboptimal patient management.
It is difficult to know whether harm has been done to a patient with BAV disease with marked dilatation of the ascending aorta and mild–moderate involvement of the arch who only underwent replacement of the ascending aorta and AVR electively. Conversely, harm will be done if the transverse arch is replaced in inexperienced centers when the arch dilatation is only modest. However, this raises the issue of who should do these procedures in the first place. It is clear from our and Westhoff-Bleck and coworkers' data2 that the aortopathy of BAV disease extends into the aortic arch in a large fraction of patients with a BAV. We aim to provide a definitive surgical procedure at the time of the initial operation, which means complete resection of all weak and dilated thoracic aortas. This is justified by the facts outlined in our report that the incremental surgical risk to the patient is minimal or absent in our hands.
Let us consider the following numbers published by Januzzi and coworkers3 from the International Registry of Aortic Dissection registry. In their database, 68 patients were younger than 40 years of age at the time of aortic dissection; of these 68 patients, 9% had a BAV. Importantly, 12% of patients had had a previous AVR at this young age. The aortic disease of those having undergone AVR is not described. It is likely that the majority of these patients had BAV disease given that degenerative aortic diseases are unlikely to present so early and that patients with the Marfan syndrome and severe aortic regurgitation owing to annuloaortic ectasia probably would have received full aortic root replacement earlier. If indeed this is the case, the majority of these patients were harmed by not having a complete resection of their diseased aortas at the time of AVR. This notion is supported by Borger and colleagues' conclusion4 that leaving ascending aortas of 4.5 to 5.0 cm in diameter at the time of AVR for a BAV is dangerous and results in patient harm. More telling are the data reported by Russo and colleagues,5 who compared 50 patients with BAV to 50 similar patients with a tricuspid valve (TAV) after AVR. These patients were followed up for a maximum of 27 years. Of the 50 BAV patients, 7 suffered sudden death and 5 presented later with acute aortic dissection. At the time of presentation or follow-up, the mean aortic diameter in the BAV group was 4.6 cm. None of the TAV patients sustained either complication. Although the natural history of asymptomatic BAV patients treated medically is relatively benign, as recently reported by Michelena and coworkers,6 it appears that surgically referred patients, as might be anticipated, may have a more malignant natural history.
In our patients with cluster IV aortic dilatation, the average aortic diameter was 3.6 cm at the takeoff of the innominate artery; traditional clamping of the aorta and replacement of the ascending aorta in such circumstances would leave behind at least a 4.0-cm diameter aorta extending into the arch. In our minds, this is inadvisable and may cause harm over the long term. We believe that at a minimum the surgeon should perform an open distal anastomosis and resect some of the dilated, soft aortic arch. Our preference includes a sigmoid-shaped tailoring of the graft leaving only a narrow tongue of arch along the greater curve and arch branches; this "peninsula style" arch replacement removes almost the entire pathologic transverse arch without resorting to an end-to-end distal aortic anastomosis and separate arch branch anastomoses. With adequate preparation, moderate hypothermia, and antegrade selective cerebral perfusion, this has been a safe and reproducible procedure in our hands for nearly 10 years and has been associated with very low morbidity and mortality rates, including stroke. It is unclear to us why this approach is avoided by many surgeons.
Given our experience, we continue to argue for a more aggressive stance regarding the aortopathy of BAV at the initial operation. We also recognize that simpler approaches might be safer at other centers where many dozens of arch replacements are not done each year, and we would hope that insightful surgeons would be honest in discussing with their patients individual risk versus benefit in treating this disease in his/her hands at his/her institution. However, the surgeon who leaves behind a substantial segment of dilated, abnormal aorta at the time of the first operation in a patient with BAV disease should recognize that he or she has most likely performed—for whatever reason—an incomplete procedure, something E. Stanley Crawford, MD, told us over 20 years ago was the "great surgical sin of omission."
References
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