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ORIGINAL ARTICLE

Repair of aortic root in patients with aneurysm or dissection: comparing the outcomes of valvesparing root replacement with those from the Bentall procedure

Edvard SkripochnikI; Robert E. MichlerI; Viktoria HentschelIII; Siyamek Neragi-MiandoabII

DOI: 10.5935/1678-9741.20130072

ABBREVIATIONS AND ACRONYMS

AI: Aortic insufficiency

AV: Aortic valve

AVR: Aortic valve replacement

INR: International normalized ratio

MI: Myocardial infarction

RBC: Red blood cells

STJ: Sinutubular junction

VSR: Valve-sparing root replacement

INTRODUCTION

Management of aortic root aneurysm or dissection has been evolving in recent decades. The current trend is a valve-sparing aortic root (VSR) replacement as well as restoring the diameter of the aortic annulus and sinotubular junction (STJ) [1-3]. Preservation of the native aortic valve (AV) results in maintenance of proper hemodynamics and prevention of thromboembolic complications by avoiding the use of a prosthetic valve and anticoagulation [1,4-6]. Preserving the native valve is particularly important in younger patients who refuse a mechanical valve. The crucial factors when attempting to preserve the function of the AV include adequate size and morphology of the leaflets, diameter of the STJ, and the diameter of the aortic annulus [2]. If the AV leaflets are grossly normal and aortic insufficiency (AI) is secondary to dilation of the STJ or aortic root, the native valve can be spared [6-9].

The purpose of this study was to evaluate the overall survival and compare the short- and mid-term outcomes in patients who underwent VSR with patients who underwent the Bentall procedure.

 

METHODS

We retrospectively analyzed data on 70 patients with aortic root pathology (aneurysm or dissection), who underwent aortic root replacement with either the valve-sparing technique (VSR) or the Bentall procedure between 2007 and 2011 at our institution. All operations were performed using a standard approach with a median sternotomy and extracorporeal circulation. A right axillary artery or innominate artery cannulation was performed in selected cases. The patients who underwent the Bentall procedure, who received a mechanical valve, were postoperatively started on anticoagulation using warfarin, and an international normalized ratio (INR) ranging from 2.5 to 3.0 was maintained.

Statistical Analysis

Patients' demographics, risk factors, and postoperative outcomes were reviewed retrospectively. Perioperative mortality was defined as death for any reason occurring within 30 days after the operation or any time during the same hospitalization, regardless of the length. Survival curves were generated using Kaplan-Meier methods. For continuous variables, correlations were calculated with the Student t-test. Data analysis was performed with the Grafpad Prism program (GraphPad Software Inc., La Jolla, USA). This study was approved by the institutional review board at our institution.

 

RESULTS

We evaluated 70 patients who had undergone a dissection or aneurysm of the aortic root: 25 patients had VSR (23 males and two females) and 45 patients (34 males and 11 females) had the Bentall procedure. Patients with VSR were younger with a mean age of 55.4 ± 14.8 years compared to the Bentall patients who had a mean age of 60.6 ± 12.7 years (P=ns). Overall, 57 patients had an aneurysm and 13 patients had dissection of the aortic root. In patients who had replacement of the aortic root and valve, 30 patients had the traditional Bentall procedure with a mechanical aortic valve prosthesis, 10 patients had the Bio-Bentall (replacement of the aortic valve with a bioprosthesis) procedure, and five patients had a homograft. Table 1 illustrates the patients' characteristics, which were similar in both groups; however, seven patients in the Bentall group had previous myocardial infarction (MI) whereas none in the VSR group had previously experienced MI (P=0.044). There was no significant difference in mild or severe preoperative AI between the two groups; however, more patients in the SVR group (32%, n=8) had moderate AI, compared to those in the Bentall group (8.8%, n=4), (P=0.02). In the VSR group, three patients had undergone emergency surgery, and the remaining patients had had an elective procedure. The total perfusion time was shorter in the VSR group (222.7 ± 81.1 min) compared to the Bentall group (246.9 ± 89.8 min), P=0.27.

 

 

The intraoperative need for blood transfusion was less in the VSR group compared to the Bentall group (3 units vs. 20 units, P=0.0074), which may be due to higher preoperative hematocrit in VSR patients in our series (41.8 ± 3.99 vs. 31.6 ± 4.33, P=0.0018). Concurrent CABG was performed in 8 (32%) patients in the VSR group and in 12 (26.6%) in the Bentall group (P=0.78). There was no significant difference in perioperative mortality between the two groups; 8% (n=2) and 13.3% (n=6), for VSR and Bentall groups, respectively (P=0.7, ns). Table 2 demonstrates the intraoperative parameters and differences between the two groups.

 

 

Further, the incidence of postoperative adverse events remained similar between both groups (Table 3). Postoperatively, 17 and 26 patients in the VSR and Bentall groups, respectively, required red blood cell (RBC) transfusion (P=ns). Total duration of post-operative ventilation was 51.7 ± 84.2 hours for the VSR group and 56.2 ± 121.9 for the Bentall group (P=0.89). The overall length of stay in the critical care unit was slightly longer for the Bentall group (152.5 ± 218.2 hours) compared to for the VSR group (116.6 ± 106.0 hours) (P=0.5). The overall length of stay was 10 ± 8.10 days for the VSR group and 11 ± 9.52 days for the Bentall group (P=0.89).

 

 

The prolonged length of stay for Bentall patients may be related to anticoagulation and required time to adjust the INR prior to discharge from the hospital. The one-year survival was 92% for the VSR group and 78% for the Bentall group; the estimated survival at seven years was 92% for the VSR group and 78% for the Bentall group (95% CI [0.1275 to 1.215], P=0.1). The type of procedure did not impact readmission rate to the hospital. Postoperative echocardiogram was performed in 18 VSR patients (18/25; 64.3%), of which only one patient (1/18; 5.5%) had mild to moderate AI, 7 patients (7/18; 38.9%) had mild AI, and the remaining 10 patients (10/18; 55.5%) had trace AI at a median follow-up of 20 months. The freedom from aortic valve replacement following VSR at a median follow-up of 20 months was 100% (Figure 1).

 

DISCUSSION

The Bentall approach has traditionally been the gold standard for aortic root pathology; however, this approach has been challenged by the valve-sparing root replacement [1, 10-13].

The VSR can be performed without increased mortality and morbidity compared to the Bentall procedure [1,11,14,15]. The perioperative mortality in our series was 8.0% (n=2) and 13.3% (n=6) for the VSR and Bentall procedures, respectively (P=0.7, ns), which is in line with the published literature [1,11,13-15]. The better survival in the VSR group in our series may be a reflection of younger age in these patients (55.4 ± 14.8 years compared to 60.6 ± 12.7 years in the Bentall group); however, the difference in survival was not statistically significant. The perioperative mortality was higher in patients presenting with cardiogenic shock [15,16], long cardiopulmonary bypass and cross clamp times, concomitant CABG, and red blood cell transfusion [15]. In the Bentall group, 8 patients had undergone emergent surgery and the remaining patients had had elective surgery.

Considering the small number of patients, we did not find emergency surgery to be a risk factor for operative mortality. The one-year survival in our series was 92% for the VSR group and 79% for the Bentall group; the seven-year survival was 92% for the VSR group and 79% for the Bentall group. Although survival was favorable following VSR, this difference was not statistically significant. Cameron et al. [11] reported favorable survival following aortic valve reimplantation in a series of 372 Marfan patients; 269 patients underwent the Bentall procedure, and 85 patients had VSR (the David reimplantation procedure was performed in 44 patients).

This observation was supported by Sheick-Yousif et al. [17], who reported a favorable outcome of valve reimplantation in 209 Marfan patients with AI secondary to dilatation of the aortic root or the STJ. Kerendi et al. [18] reported their experience with root replacement in 110 patients: 73 Bentall procedures and 37 David procedures. There was a slight, but non-significant increase in mortality with the Bentall procedure (8.2%) compared with the David procedure (5.4%), which is in concert with our results. We did not observe any significant differences with respect to postoperative stroke, renal failure, or respiratory failure between the two approaches, which has been confirmed by other authors [1,10-12,18]. Freedom from aortic valve replacement (AVR) at a mean follow-up of 8.8 months in Kerendi et al. [18] series was 94.3%. The authors argued that a VSR replacement can be performed safely in the setting of acute dissection, severe AI, and reoperations with acceptable early results. The freedom from AVR following VSR was 100% in our series; however, our results are limited by a short median follow up of 20 months.

Our data demonstrated that VSR is not associated with increased postoperative morbidities; in fact, intubation time, length of stay in the critical care unit, and overall length of stay were favorable following VSR compared to those in the Bentall group. The most common complications are bleeding and neurological sequelae [15]. In a series of 388 patients (reimplantation 72, remodeling 77, tailoring 239), stroke occurred in 4.6% (18/388) [1]. In a large series of 430 patients [19] who underwent VSR (remodeling in 401, reimplantation in 29) the early mortality was 2.8%, and actuarial survival at 10 years was 83.5%. Ten-year freedom from AI grade II or greater was 85%. Operative technique (remodeling vs. reimplantation) was not associated with an increased risk of late AV regurgitation or need for AV replacement. Long-term outcome of VSR was not influenced by the technique of root repair but by the preoperative aortic root geometry and postoperative cusp configuration [19].

Some authors reported that a preoperative aortoventricular junctional diameter greater than 28 mm was predictive of valve repair failure [19,20]. Although we did not evaluate the AV junction diameter, in our small series with a short median follow up (20 months), the AV function in the VSR group was excellent and none of the patients had significant AI. In David et al. [10] series 228 patients underwent reimplantation of the aortic valve, and 61 patients underwent remodeling of the aortic root, with excellent results. The 12-year survival was 82.9% with no difference between both techniques.

The incidence of AI requiring reoperations was higher following remodeling of the aortic root. Freedom from reoperation at 12 years was 90.4% after remodeling, and 97.4% after reimplantation (not statistically significant). Freedom from moderate or severe aortic insufficiency at 12 years was 91.0% after reimplantation [10]. Dias et al. [3] reported favorable outcome with an actuarial survival and freedom from reoperation of 94.4% and 96% within 11 years of follow-up, respectively [3]. In a series of 388 patients (72 reimplantation, 77 remodeling, and 239 tailoring), the hospital survival rate was 97.4% (378/388) [1].

 

CONCLUSION

Aortic VSR can be performed with acceptable morbidity and mortality. The mid-term follow up demonstrates adequate freedom from aortic insufficiency. Log-term follow up in larger series may demonstrate possibly superior long-term survival following valve sparing root repair compared to the Bentall procedure. In addition, a valve-sparing approach reduces all of the risks inherent to a mechanical or biologic prosthetic, particularly in younger patients.

REFERENCES

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No financial support.

Author's roles & responsibilities

ES: Collecting data, manuscript writing

REM: Manuscript writing

VH: Statistical analysis

SNM: Design of the project, manuscript writing

Article receive on Sunday, July 14, 2013

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