The aggressive approach and Freedom from re-operation?
The advocating of an aggressive intervention to replace the entire root is yet to receive a wide consensus. 4,5,6,7 Surgically replacing the entire root reduces the risk of subsequent dilation of the aorta, future occurrences of aortic insufficiency, and the possibilities of repeat dissections. These potential benefits would be expected to increase the chances of freedom from re-operation, and improving outcomes for long term survival.4
A retrospective study of 316 patients undergoing repair for ATAAD, had a small sample size of 40 patients undergoing a complete root replacement. With a mean average follow up of 26 months (94.6% complete), Nishida H et al20 reported that these patients had a 100% freedom from re-operation at 5 years. This was a significantly more favorable outcome (p=0.029) than the patients not having their aortic root replaced, who only had a 68.7% freedom from re-operation. The aortic root events that led to the need for re-intervention, included 25 aortic dilations, 3 cases of aortic insufficiency, and 1 pseudoaneurysm20; These are long term physiological complications which a root replacement can help avoid.4
A much larger study by Di Eusanio et al.4 comprising of 1,995 patients, reported that there was no statistically significant difference (p=0.770) in the rates of freedom from re-operation at 3 years between the patients undergoing Bentall and VSRR methods of repair, compared to those undergoing the conservative repair procedure. However despite the large sample size, with a follow up that was only 54% complete, and results recorded at only 3 years, it is difficult to be able to use these results alone to conclude that there would be no significant differences in the long term for rates of re-operation.4
Another study in the literature which although reported statistically insignificant results, had in fact shown a clear trend of their crude results towards more favourable outcomes for root replacement in regards to freedom from re-operation.22 The 9 year freedom from re-operation was reported by Ergin M and colleagues22 as 87.5% for the root replacement group, compared to 63.0% for the group without root being replaced.9
Hysi I and colleagues reported outcomes for results up to 15 years following the primary surgery and published their results with a much longer average follow up period. The authors were able to show that adding a root replacement in the treatment for ATAAD provides significantly better (p=0.02) outcomes for freedom from re-intervention.7 There were 93.4% of patients with root replaced that were free from re-operation at 15 years, compared to only 78% for those that underwent a supracomissural repair alone. This was another study where the reasons for re-operations would have had a far lower risk of occurrence had a root replacement been performed in those patients. 4,7,20
Chiu P and colleagues6, had included 293 patients in their retrospective study comparing root replacement(n=81) to limited root repair(n=212), for treatment of TAAD. The article reported an overall rate of re-operations to be 11.8% for the root repair group, compared to 0% for the root replacement group (p=0.001). This is of course again highly limited by the short median follow up time of 2.1 years, and the results being from a single tertiary center alone.
A short follow up period which is also not well completed, adds significant limitations to the literature discussing the fate of the aortic root.4-24 Given that much of the literature is already weakened by their retrospective studies based on a single center,4-26 such further limitations have strong impacts on the already hindered reliability, bias, and reduced statistical power from the small sample sizes.
The study published by Castrovinci S and colleagues27comparing 199 patients that underwent Bentall (n=108) or David (n=11) procedures for root replacement, with those that had a conservative root repair. The study reported results for freedom from re-operation until 7 years period with a 100% follow up rate, the results for root replacement group was 96% freedom at 7 years, compared to only 80% for the conservative repair (p=0.02). However following adjustments for propensity score matching using a considerable number of covariates, the rate of freedom from re-operation for root replacement group and without root replacement at 7 years was; 98% and 86% respectively, however now with a log-ranked p value of 0.06.27