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J Thorac Cardiovasc Surg 2004;127:391-398
© 2004 The American Association for Thoracic Surgery
Surgery for acquired cardiovascular disease |
a Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, Hannover, Germany
Read at the Eighty-third Annual Meeting of The American Association for Thoracic Surgery, Boston, Mass, May 4-7, 2003.
Received for publication May 3, 2003; revisions received July 15, 2003; accepted for publication July 30, 2003.
* Address for reprints: Matthias Karck, MD, Department of Thoracic and Cardiovascular Surgery, Hannover Medical School, 30623 Hannover, Germany
Karck{at}thg.mh-hannover.de
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Abstract |
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PATIENTS AND METHODS: Between March 1979 and April 2002, 119 patients with clinical evidence of Marfan syndrome underwent composite graft replacement with mechanical valve conduits (n = 74) or aortic valve-sparing reimplantation according to David (n = 45). The underlying causes were aortic dissection type A (43 patients) and aneurysms (76 patients).
RESULTS: Patients undergoing aortic valve reimplantation were younger compared with patients undergoing composite grafting (28 vs 35 years, P = .002) and had longer intraoperative aortic crossclamp times (125 vs 78 minutes, P < .0001) and extracorporeal circulation times (162 vs 124 minutes, P < .0001). Early postoperative mortality was 6.8% (n = 5) in patients undergoing composite grafting and 0% in patients undergoing aortic valve reimplantation (P = .15). Mean follow-up was 30 months for patients undergoing aortic valve reimplantation and 114 months for patients undergoing composite grafting. Freedom from reoperation and death after 5 years postoperatively was 92% and 89% in patients undergoing composite grafting and 84% and 96% in patients undergoing aortic valve reimplantation (P = .31; P = .54), respectively. Thromboembolic complications or late postoperative bleeding occurred in 17 patients undergoing composite grafting, and an early postoperative event occurred in 1 patient undergoing aortic valve reimplantation.
CONCLUSIONS: The results of aortic valve reimplantation and composite grafting of the aortic valve and ascending aorta with mechanical valve conduits are similar with regard to early and mid-term postoperative mortality and to the incidence of late reoperations in patients with Marfan syndrome. The low risk of thromboembolic or bleeding complications favors aortic valve reimplantation in these patients.
On the other hand, there is increasing evidence that valve-sparing operations, such as the aortic root remodeling technique according to Yacoub or the reimplantation technique according to David, can be applied with good functional long-term results in patients with Marfan syndrome too.7-9 This observation and the surprisingly long freedom from valve failure of up to 29 years that has been reported after 4 valve-sparing aortic root operations by Senning are good reasons to contest the restraints in this regard.4
Since 1993, we have used the aortic valve reimplantation technique according to David and have expanded the indications for this operation from acquired root pathologies to patients with Marfan syndrome with aneurysms of the aortic root.10 This report summarizes our experience with the reimplantation technique in 45 patients with Marfan syndrome in comparison with a nonmatched cohort of patients with Marfan syndrome who underwent aortic root replacement with mechanical valve conduits.
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Materials and methods |
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TopAbstractMaterials and methodsResultsDiscussionDiscussionReferences |
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Table 1 summarizes the preoperative characteristics of patients who underwent aortic valve reimplantation or aortic root replacement with a mechanical valve conduit. Table 2 shows the operative data. Patients were followed up at annual intervals. Doppler echocardiography was performed in patients with aortic valve reimplantation. In addition, all patients with aortic dissection or subcritical aortic dilatation were reinvestigated serially by computed tomography. The mean follow-up was 30 ± 27 months (1-95 months) for patients who underwent aortic valve reimplantation and 114 ± 63 months (2-249 months) for patients who underwent composite graft replacement of the aortic valve and ascending aorta. None of these patients were lost to follow-up. Infectious, thromboembolic, and bleeding complications were recorded as recommended by the guidelines of the American Association for Thoracic Surgery and Society of Thoracic Surgeons.12
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2 test. |
Results |
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Altogether, 10 patients required reexploration of the mediastinum for bleeding (2 in the valve reimplantation group and 8 in the root replacement group).
There was no perioperative stroke, myocardial infarction, or infection in the reimplantation group. In the root replacement group, 2 patients had nonfatal strokes, 2 patients had reversible ischemic neurologic deficits, and 1 patient had a transient ischemic attack. None of these patients underwent additional mitral valve surgery. The anticoagulant status reported closest to the respective events ranged between 2.5 and 3.5 international normalized ratio in all patients.
The length of hospital stay was 15 ± 9 days in the reimplantation cohort and 20 ± 18 days in the aortic root replacement cohort (P = .08).
There were 12 patients who had bleeding events in the root replacement group during further follow-up (3 with intracerebral bleeding, 3 with retinal bleeding, 3 with gastrointestinal bleeding, and 3 with severe epistaxis). No such episodes were reported in the reimplantation group.
Altogether, there were 17 of 69 survivors (24%) in the root replacement group with a mechanical valve substitute who experienced bleeding episodes or thromboembolic events during their follow-up. In the reimplantation group, however, only 1 patient had a transient ischemic attack early postoperatively.
Reoperations and late results
Reoperation on the aortic valve was performed in 4 patients (9%) after valve reimplantation. Technical problems during primary repair caused severe aortic valve incompetence 20 days postoperatively in 1 patient. Progressive aortic insufficiency (AI) during the first postoperative year occurred in 2 patients. At reoperation, cusp prolapse as the result of inadequate technique at the primary repair was identified as the cause of valve failure. Both patients demonstrated less than optimal cusp coaptation with aortic regurgitation greater than grade 1 in the early postoperative period. One patient received a prophylactic aortic valve replacement for AI grade II during aortic arch replacement 41 months after the primary repair. Preoperative echocardiography had revealed mild cusp prolapse beyond the inferior edge of the vascular graft. In all patients, valve replacement was performed within the Dacron prosthesis using mechanical prostheses. All patients recovered promptly from the second operation.
Seven patients (9%) underwent cardiac reoperations after root replacement; indications were related to the composite graft in 6 of these patients. Two patients had prosthetic valve endocarditis. Other indications were persistent perfusion of the perigraft space in 1 patient, malfunction of the prosthetic heart valve in 1 patient, perforation near a coronary reimplantation site in 1 patient, and a relevant subprosthetic ventricular septal defect in 1 patient. One patient underwent heart transplantation for progressive cardiomyopathy late after root replacement. Two of the 7 patients in this subcohort died early postoperatively. Both patients underwent reoperation for prosthetic valve endocarditis. In 1 of these patients, the conduit was replaced by another composite graft, whereas the other patient underwent partial replacement of the ascending aortic prosthesis together with direct closure of a paravalvular leak. The former patient died as a sequel of early postoperative resuscitation and subsequent stroke, and the latter patient died of septic complications 10 days postoperatively. The other 5 patients are alive.
Figure 1 shows freedom from reoperation in both groups of patients; at 5 years it was 84% ± 8% for patients who underwent aortic valve reimplantation and 92% ± 3% for patients who underwent aortic root replacement (P= .31).
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Figure 2 shows the survival in both groups of patients. Survival at 5 years was 96% ± 4% for patients who underwent aortic valve reimplantation and 89% ± 4% for patients who underwent aortic root replacement (P = .54).
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After aortic valve reimplantation, 3 of the 45 surviving patients (6%) underwent downstream aortic reoperations. The indications were dilatation of a chronically dissected aortic arch, dilatation of a nondissected arch, and a secondary subacute type B aortic dissection. All patients who underwent reoperation were alive at the end of follow-up.
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Discussion |
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According to a multicenter review by Gott and colleagues,4 elective repair of the aortic root in patients with Marfan syndrome carries a perioperative mortality risk of 1.5%. The cumulative survival in that collective series was 85% at 5 years. These results were obtained because aortic root replacement by composite grafting of the aortic valve and ascending aorta has proven to be a straightforward and safe procedure.16
The zero early postoperative mortality we obtained with the David procedure can well compete in this regard even though the aortic crossclamp and extracorporeal circulation times were longer when compared with composite grafting. This result is in accordance with the early mortality rates for elective patients reported by David's group and the early results of the remodeling procedure according to Yacoub.7,9
Survival and mid-term postoperative outcome with this technique have been satisfactory so far, with 3 patients who died of reasons that were not attributable to valve reimplantation. The cumulative survival measures 96% at 5 years, which is comparative to results of root replacement and other series of patients with valve-preserving procedures.7,9,16
The most important adverse effect of valve repair remains valve failure. Early in our experience with valve reimplantation, 4 patients had to undergo reoperation for technical reasons. A detailed analysis of the intraoperative echocardiographic findings in 3 of these patients indicated that resuspension of the commissures was too low, thereby leading to cusp prolapse. We thus believe that radical dissection of the aortic root and adequate height of resuspension of the commissures are important to avoid early valve failure.10 It remains to be determined to what extent the structural fibrillin-1 defect can affect the stability and durability of the cusps after valve reimplantation. So far, we have no evidence (from echocardiography during follow-up or direct inspection of explanted valves) that obvious degenerative changes in the cusps were possibly attributable to contact with the prosthetic vascular graft. In our opinion, both aspects together with the more radical support of the diseased aortic wall and the routine annular stabilization are good reasons to continue to use David and Feindel's8 original technique (David I operation) in patients with Marfan syndrome. This applies to patients with normal cusps, which are generally found in root aneurysms smaller than 55 mm. Valves with dilated cusps and multiple stress fenestrations, as typically seen in larger root aneurysms, should be replaced.9 It is conceivable, however, that the lack of sinuses of Valsalva still predisposes to leaflet damage, which could unmask only during further follow-up. This concern has led to modifications of the classic David I operation (David IV or V) and the clinical introduction of vascular prosthesis incorporating artificial sinuses of Valsalva.17-19
The 2 study groups (valve reimplantation and root replacement with a mechanical aortic valve prosthesis) had a number of different perioperative variables (Table 1). One of the reasons why patients who underwent valve-sparing operations were younger when compared with patients who received a conduit probably resides in the more recent tendency to operate on root aneurysms at smaller diameters (4.5-5 cm) than 20 years ago in patients with Marfan syndrome. During recent years, we have tried to preserve the aortic valve in acute aortic dissection type A too. We believe there are 2 reasons why the proportion of patients with nondissecting aneurysms was still larger in patients with preserved aortic valves than in patients with replaced valves when looking at the whole study period: (1) Increased alertness among physicians with regard to the possible complications of Marfan syndrome may have contributed to the fact that fewer patients with Marfan syndrome have presented with type A aortic dissection during recent years. This may explain why only 5 patients had to undergo operation for this diagnosis during the last 7 years of the study period when compared with the 38 patients during the first 16 years. (2) The David operation was introduced into our clinical practice only during the last 9 years of the approximately 23-year study period. Therefore, the statistical impact of the small number of patients with aortic dissection type A who had the chance to undergo valve reimplantation is relatively small, even though this operation was performed in all 5 patients who underwent operations since 1995 except for 1 patient with severely damaged leaflets.
No redo cases are documented in the cohort with valve reimplantation, whereas 12% of patients in the replacement group had undergone previous cardiac surgery. This finding probably reflects a surgical prevalence to accept the longer crossclamp times of aortic valve-preserving surgery in primary procedures rather than in redo interventions.
Another difference between the cohorts was the treatment of concomitant mitral valve insufficiency: There were no mitral valve replacements in the reimplantation group, whereas there were no mitral valve repairs in the root replacement group. With regard to the necessity of long-term anticoagulation, this finding reflects the efforts to repair not only the aortic valve but also the mitral valve whenever indicated.
In addition to these variables, the different length of follow-up in both cohorts certainly limits their statistical comparability. On the other hand, it is apparent that there were virtually no postoperative valve-related events in the reimplantation group. In contrast, 7.2% of the survivors of aortic root replacement with a mechanical aortic valve substitute have had thromboembolic complications, and 17.4% of patients have had bleeding episodes. Although other causes for these complications are conceivable, these data well reflect the incidence of the adverse events that have been attributed to long-term phenprocoumon medication after mechanical valve replacement.5 Furthermore, the risk for dissection or dilatation of downstream aortic segments with the need for vascular reoperations renders patient management more difficult when long-term anticoagulation is necessary. Considering these aspects and in view of the presented data, we favor this valve-preserving operation in patients with Marfan syndrome, provided the valve cusps appear normal. However, only true long-term results will clarify its definite value in these patients.
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Discussion |
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TopAbstractMaterials and methodsResultsDiscussionDiscussionReferences |
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I have been performing this operation for some 15 years, and I still find it a difficult operation to teach—not the technical aspects of reimplanting the aortic valve into a tube but the operative judgment of whether to save or replace an aortic valve and to select the size of the graft for the reimplantation. How did you choose the size of the graft? What guidelines do you use in the operating room to pick a graft of 34 or 26 mm?
Second, what do you do for the elongated cusps? Invariably if a patient has an aortic root aneurysm, the cusps won't be entirely normal. Thus, the principles of functional anatomy of the aortic valve are not easily applicable in patients with aortic root aneurysm. In other words, it has been my experience that the cusps are often elongated, particularly the noncoronary cusp. If you take a graft of a given size, the cusps may prolapse at the end of the operation. Do you repair the cusps? Do you shorten them?
Finally, isn't the creation of the neo-aortic sinus important for the function of the aortic valve? There is an increased amount of evidence suggesting that the velocity of closure of the aortic cusps decreases when neo-aortic sinuses are created.
Dr Karck. I am aware that you have developed a specific formula to calculate the optimum size of the tube graft to use. This is a difficult formula for us, and reviewing our data, it turns out that the vast majority of patients, including patients with Marfan syndrome, received a 28-mm prosthesis if male and a 26-mm prosthesis if female. The results we obtained, even though I understand the theoretical point, support the selection of these tube graft sizes. Few patients with exceptionally wide annuli had tube grafts with wider diameters.
Dr David. I'm sorry, you don't have a criterion for selecting 26 or 28? It is random?
Dr Karck. No, we measure, but this resulted in 28-mm or 26-mm tube grafts for the majority of patients with Marfan syndrome.
With regard to cusp elongation, we carefully assess the aortic valve, particularly in the area of the commissures. If there are stress fenestrations, we replace this valve instead of trying to reconstruct it. Commonly we see these stress fenestrations in patients who have a very wide annulus. I missed the third question.
Dr David. The need to create neo-aortic sinuses as opposed to a straight tube.
Dr Karck. There are some data on the importance of sinus function. From the work of Dr Leyh, who analyzed this aspect between the Yacoub operation and the David operation comparatively, we learned that the lack of sinus function has not affected the clinical outcome so far. In other words, with the follow-up we have accumulated so far, we do not see deterioration of the cusps or any disadvantages that may be attributable to the loss of sinus function.
Dr Gerald M. Lawrie (Houston, Tex). I enjoyed this beautifully presented article. I wanted to make a brief comment about the long-term natural history of this disease. Ten years ago, we had the opportunity to publish a report on a series of 277 patients who underwent operations at Baylor in the 1960s and 1970s before composite grafts were prevalent (Lawrie GM, Earle N, DeBakey ME. Long-term fate of the aortic root and aortic valve after ascending aneurysm surgery. Ann Surg. 1993;217:711-20). We ended up with a series of patients with simple tube grafts, with or without a separate prosthetic aortic valve replacement. As a result, we had 277 aortic roots and 118 native aortic valves that we were able to follow for up to 40 years.
What we found was that simple tube graft replacement in the patients without Marfan syndrome was a very reliable operation; 96% of the roots and their native valves came through 10 years without any problem. On the other hand, the patients with Marfan syndrome did not do so well. These patients had an 86% freedom from reoperation for their root disease and only a 75% survival of their Marfan valves, which were originally competent. This 25% incidence of AI at 10 years is very similar to what Dr Tirone David published last month for his patients undergoing valve-sparing surgery (de Oliveira NC, David TE, Ivanov J, Armstrong S, Eriksson MJ, Rakowski H, et al. Results of surgery for aortic root aneurysm in patients with Marfan syndrome. J Thorac Cardiovasc Surg. 2003;125:789-96).
Although this isn't a direct parallel to your article, we did note several points that would bear on your presentation. The first is that most of these problems emerged in the 5- to 10-year time interval. We had very few problems, almost no problems at all, in the 0- to 5-year interval. So I would continue to be cautious about the wide application of this concept in Marfan syndrome. This is a real problem. Again, 40 of 277 patients had Marfan syndrome, and 50% of the reoperations in the entire group were in those 40 patients.
I am glad to see you did pay attention to the incidence of recurrent AI in great detail. I think we need to get back somewhat parallel to the mitral repair situation in which we report the success of our reconstructions according to the presence or absence of AI rather than reoperation rates. AI is serious but sometimes well tolerated for long periods of time, and I think we need to focus on whether there is a competent valve or not.
Dr Karck. I agree. We have to wait until we have accumulated much longer follow-up times. It is possible that beyond 5 years of follow-up, complications will occur. So far, however, the results are quite encouraging. Therefore, we will continue to offer this operation to patients with Marfan syndrome too.
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Acknowledgments |
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References |
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