Abstract

Methods: Between October 2009 and May 2014, 46 patients (22 males, 24 females; mean age 74.74±7.35 years; range 56 to 87 years) were included. The patients were divided into two groups including 25 patients with conventional stented bioprosthetic valves in group 1 and 21 patients with sutureless aortic valves in group 2.

Results: The maximum postoperative aortic gradient was 20.1±5.5 mmHg for the sutureless group and 28.7±13.9 mmHg for the stented group (p=0.038). The mean postoperative gradient was 10.3±3.4 mmHg for the sutureless group and 15.1±8.4 mmHg for the stented group (p=0.052). No in-hospital mortality was seen in the sutureless group; however, five patients in the stented group died during the hospital stay (p=0.054).

Conclusion: Sutureless aortic valve replacement is a novel surgical treatment modality, yielding excellent hemodynamic conditions with a short ischemic time.

Aortic valve replacement (AVR) with any kind of bioprosthesis is the preferred method in elderly, particularly, thanks to satisfactory hemodynamic performance and postoperative durability without warfarin-related complications.[3] Transcatheter aortic valve implantation (TAVI) procedures have been developed and extensively used in high-risk patients who are ineligible for standard surgery using cardiopulmonary bypass (CPB). However, it seems necessary to improve its quality and safety due to the potential risks of serious complications such as pacemaker implantation, paravalvular leaks, and increased neurological events.[4]

In the high-risk patient population, replacement of the aortic valve with a sutureless prosthesis held in place by radial forces represents an interesting idea. This novel technique offers complete removal of the diseased aortic valve and calcifications, reducing surgical injuries and operating time. Sutureless aortic bioprosthesis implantation is a feasible alternative for high-risk patients with aortic valve disease.[2]

In this study, we compared the early outcomes of sutureless aortic valves versus conventional stented aortic bioprosthetic valves.

Methods

The patients were divided into two groups including 25 patients with conventional stented bioprosthetic valves in group 1 and 21 patients with sutureless aortic valves in group 2.

Three different rapid deployment valves are currently approved for the clinical use in Europe: the Enable (Medtronic, Minneapolis, MN, USA), the Perceval S (SorinBiomedica Cardio Srl, Sallugia, Italy), and the Edwards Intuity (Edwards Lifesciences, Irvine, CA, USA) valves. We used Perceval S in 17 patients (80.95%) and Edwards Intuity in four patients (19.05%) in the sutureless group.

In the stented group, we used Sorin Soprano^TM in 20 patients (80%) and St. Jude Trifecta in five patients (20%). Valves were chosen according to the optimal effective orifice area in respect of the body surface area of each patient.

The EuroSCORE II results were similar between both groups (2.8±1.5 for the sutureless group and 3.4±2.4 for the stented group; p=0.269). As the sutureless valves are commercially available in the Turkish market since January 2012, we have widely used the sutureless valves to reduce the operation time. Also, we have been implementing these valves in highrisk patients and those requiring additional procedures. In the high-risk patients such as our population, the valve selection should be optimal.

All procedures were performed by a single surgeon. Under general anesthesia and orotracheal intubation, all patients undergoing AVR were placed on CPB after complete sternotomy. Myocardial protection was achieved by antegrade and retrograde administration of blood cardioplegic solution on induction and maintained with retrograde administration of cold-blood cardioplegic doses every 20 minutes in accordance with the institutional routine practice. Finally, warm-blood dose was administered before releasing the cross-clamp.

In our series, we used six (28.57%) miniextracorporeal circulation (MECC) in the sutureless group and others were conventional CPB circuit with a roller pump. Myocardial protection was achieved by antegrade potassium chloride added calafiore solution (Politecnico di Torino, Italy). If needed, it was repeated during the procedure through the left and right coronary artery orifices.

Perceval S
After the separation of the aorta from the pulmonary trunk, a transverse aortotomy was made approximately 1 cm above the sinotubular junction. After complete visualization of the valve, the leaflets were excised and the annulus was decalcified. The aortic orifice was measured with the original size of the bioprosthesis.

This bioprosthesis was able to be collapsed through a dedicated device and positioned by means of a specific delivery system. The delivery system loaded with the collapsed stent-mounted valve was guided to its correct position by sliding it over the three guiding sutures (4-0 polypropylene), positioned at the nadir level of each resected cusp. Once the delivery system was in position, the prosthesis was deployed, the guiding sutures were removed and the valve was finally in place; at this point a post-dilation modeling was performed with a dedicated balloon (30 seconds at a pressure of 4 atmosphere) (Figure 1).

Figure 1: An intraoperative view of Perceval S.

Edwards intuity
After separation of the aorta from the pulmonary trunk, a transverse aortotomy was made approximately 1 cm above the sinotubular junction. Valve preparation involved two 1 mm washes in saline solution. The inflation device was filled with saline (minimum 30 mL) and the balloon catheter was attached. A braided, non-pledgeted suture was inserted as a figure-of-eight at the nadir of each aortic sinus. The suture was then passed through the sewing ring of the valve at the black markers and snared with a tourniquet. The valve was lowered into place in the annulus -using a gentle back and forth rocking motionwhile pulling up on the guiding sutures. Once the valve was properly positioned, its position was secured with the suture tourniquets. The balloon catheter was inserted through the holding device and locked into place. Saline was injected until the appropriate pressure was achieved (between 3 and 5 atmospheres depending on the valve size). The target inflation pressure was maintained for 10 seconds and then the balloon was deflated. Three prolene sutures on the valve holder were cut and the entire holding device and balloon were carefully removed. The three guiding sutures were tied and cut. The patency of the coronary ostia was confirmed (Figure 2).

Figure 2: An intraoperative view of Edwards intuity.

Stented bioprosthesis
All patients underwent AVR through a median sternotomy using standard CPB. Myocardial protection was achieved by the infusion of antegrade blood cardioplegia and moderate hypothermia during the procedure. An oblique aortotomy extending into the noncoronary sinus was employed. The surgical technique included meticulous native annular decalcification and correct valve sizing. It was accomplished using specific sizers and accepting the largest size which fitted the decalcified annulus. The correctly sized prosthesis was subsequently implanted using interrupted pledgeted 2/0 Ethibond sutures.

The surgical procedure was completed with the closure of the transverse aortotomy for Perceval S and Edwards Intuity and oblique aortotomy for stented bioprosthesis or with the other possible associated procedures. In case of associated CABG, the distal anastomosis preceded the implantation of the prosthesis, but followed aortotomy and annulus sizing.

Transesophageal echocardiography was performed during the procedure to evaluate the pre-implantation measurements and the prosthetic function. All patients underwent transthoracic echocardiography at discharge (Figure 3).

Figure 3: A transesophageal echocardiography image.

Statistical analysis
Statistical analysis was performed using SPSS version 16.0 (SPSS Inc., Chicago, IL, USA) software. The data were expressed in mean±standard deviation (SD) for quantitative variables and percentages for categorical variables. The groups were compared using the Student’s t-test test for continuous variables and the chi-square test (or Fisher’s exact test, if required) for categorical variables. Ap value of < 0.05 was considered statistically significant.

Results

Table 1: Baseline demographic characteristics of patients

Operative and postoperative data are summarized in Table 2. Operation, CPB and cross-clamping times were statistically significantly lower in the sutureless group. The CPB time was 78.5±34.1 minutes for the sutureless group and 161.5±62.4 minutes for the stented group (p=0.000) in patients undergoing AVR without any additional procedure. Cross-clamping time was 49.2±20.9 minutes for the sutureless group and 107.9±36.4 minutes for the stented group (p=0.038). Intubation time was 8.0±2.6 hours for the sutureless group and 10.8±4.2 hours for the stented group (p=0.012). The length of intensive care unit (ICU) and hospital stays was also statistically significantly shorter in the sutureless group.

Table 2: Operative and postoperative variables

Additional procedures are summarized in Table 3. An additional root enlargement procedure (REP) was performed in two patients (8%) in the stented group to achieve an optimal orifice area. Pre- and postoperative echocardiographic variables are given in Table 4. The maximum postoperative aortic gradient was 20.1±5.5 mmHg for the sutureless group and 28.7±13.9 mmHg for the stented group (p=0.038). The mean postoperative gradient was 10.3±3.4 mmHg for the sutureless group and 15.1±8.4 mmHg for the stented group (p=0.052). Although mean and maximum postoperative gradients were statistically significant, delta values did not vary between two groups (Table 5).

Table 3: Additional procedures

Table 4: Echocardiographic findings of patients

Table 5: Postoperative changes in echocardiographic gradients compared to baseline

No in-hospital mortality was seen in the sutureless group; however, five patients in the stented group died during the hospital stay (p=0.054). Three of them underwent additional procedures. Two had REP and CABG, while one had CABG alone. Other two patients died due to cerebrovascular events.

Discussion

Aortic valve replacement with a bioprosthesis is preferred in elderly, particularly, due to its satisfactory hemodynamic outcomes without warfarin-related complications.[3] Recent published series of conventional aortic valve replacement in elderly have shown an operative mortality ranging between 4% and 10%.[6] In our study, the sutureless aortic valve was implanted after thorough surgical removal of the diseased valve, as done with conventional valve replacement. There was no in-hospital mortality in the sutureless group with a similar risk profile to the stented population. Also, REP was additionally performed in two patients in the stented group.

Unfortunately, both died during the hospital stay. It is still controversial whether REP increases the operative mortality or REP is performed in already high-risk patients. In a study by, St. Rammos et al.,[7] 15 patients underwent REP and all were females without any in-hospital mortality and with good 10-year follow-up results. In Dhareshwar et al.[8] study, REP was found to be a univariate predictor of mortality; however, the multivariate analysis revealed that it was not.

Compared to the stented bioprostheses, sutureless valves can be implanted with reduced operative time, cross-clamp time, and CPB time. This can be an advantage in patients requiring additional procedures, such as concomitant CABG in elderly. In our experiences, 11 patients (52.38%) underwent an additional procedure in the sutureless group and 10 patients (40%) in the stented group. In high-risk patients undergoing combined surgery with prolonged surgical time as well as in patients undergoing re-intervention, the use of sutureless bioprostheses is particularly invaluable for the considerably reduced implantation time.[9] In our series, there were no re-interventions in both groups. In a multicenter study, Martens et al.[10] reported a mean cross-clamp time of 58±25 minutes in consistent with our findings.

Furthermore, we recorded significantly lower maximum and mean postoperative gradients in the sutureless group according to stented group, however, the reductions of both values were not significantly different. Similarly, Borger et al.[11] showed that the mean overall pressure gradients were 11±5 mmHg in the stentless valve group. In another study using sutureless valves, the mean transaortic gradient was 11.1±4.6 mmHg,[12] in consistent with our study findings.

Paravalvular leakage (PVL) can be a result of inadequate sizing and positioning or due to inappropriate decalcification of the annulus.[13] Correct positioning of the prosthesis can be time-consuming and should be carried out accurately. Any PVL should be checked by intraoperative TEE. It is beyond any doubt that a clearly visible PVL at the time of surgery demands immediate correction.[14] In our series, PVLs were observed in none of the patient groups.

Pollari et al.[14] reported shorter ICU stay, hospital stay, and intubation time in the stentless group compared to the stented group, in consistent with our study findings. In a recent retrospective analysis of approximately 1,000 patients undergoing surgical AVR, Ranucci et al.[15] reported that aortic crossclamp time was an independent predictor of severe cardiovascular morbidity with an increased risk of 1.4% per one minute increase. Improved operative variables at the stentless group may result in shorter ICU and hospital stay and intubation time. Similar to the Pollari et al.[14] study findings, our results also suggest lower incidence of blood transfusion need.

Between two options, TAVI or surgical AVR, it still remains to be elucidated that which one is a better indication for “gray-zone” patients. D’Onofrio et al.[16] recently compared early clinical and echocardiographic outcomes of patients undergoing sutureless Perceval AVR versus TAVI using the propensity-score matching analysis. The authors showed lower mortality and PVL rates in the Perceval group. In addition, TAVI has several disadvantages such as peripheral vascular complications. In another study, Dağdelen et al.[17] reported minor vascular complications in 20% patients.

Compared to the conventional CPB, MECC was associated with lower inotropic support need, significantly lower morbidity rates, and lower incidence of stroke and respiratory insufficiency.[18] No significant changes in intraoperative or hospital mortality after MECC compared with conventional CPB were observed, either.[19] Moreover, van Boven et al.[20] reported that the use of MECC instead of conventional CPB reduced the level of oxidative stress following reperfusion after the removal of the aortic crossclamp, as well as reduced the levels of CC16 (clara cell secretory protein)-a marker of alveolar damage. In the present study, the CPB time and cross-clamping time were statistically significantly higher in the stented group than the sutureless group. The rate of additional procedures was similar in both groups, except the AVR patients. Reduced time is likely a result of the technique facility. Reduced CPB and cross-clamp time may prevent side effects of CPB including hemolysis, ischemia, and oxidative stress, thereby, reducing the mortality and morbidity.[21]

Body surface area (BSA) was statistically larger in the stented group. In our population, there was no patient-prosthesis mismatch due to REP which was performed where applicable. Optimal orifice area was achieved in all patients. The durability of bioprosthetic valves are excellent and severe patientprosthesis mismatch is infrequent.[22,23] In the stented group, we performed REP with Sorin Soprano valves in two patients. Although REP does not increase the surgical risk, it should be avoided in elderly with severe calcified aortic wall as in our population.[24]

The major limitation of the study was its small sample size in a single-center. Achievement of early outcomes alone can be deemed another limitation. Therefore, further long-term large-scale studies are required to confirm these findings.

In conclusion, this single-center experience in the sutureless aortic valve implantation represents a novel surgical treatment modality, yielding excellent hemodynamic conditions with short ischemic time. Although it is too soon to establish a conclusion, our experience indicates that sutureless aortic valves can be first-line treatment option for high-risk elderly.

Declaration of conflicting interests
The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Funding
The authors received no financial support for the research and/or authorship of this article.

References

1) Santarpino G, Pfeiffer S, Schmidt J, Concistrè G, Fischlein T. Sutureless aortic valve replacement: first-year single-center experience. Ann Thorac Surg 2012;94:504-8.

2) Eichstaedt HC, Easo J, Härle T, Dapunt OE. Early singlecenter experience in sutureless aortic valve implantation in 120 patients. J Thorac Cardiovasc Surg 2014;147:370-5.

3) Altintas G, Diken AI, Hanedan O, Yurdakok O, Ozyalcin S, Kucuker SA, et al. The Sorin Freedom SOLO stentless tissue valve: early outcomes after aortic valve replacement. Tex Heart Inst J 2013;40:50-5.

4) Zahn R, Gerckens U, Grube E, Linke A, Sievert H, Eggebrecht H, et al. Transcatheter aortic valve implantation: first results from a multi-centre real-world registry. Eur Heart J 2011;32:198-204.

5) Breitenbach I, Wimmer-Greinecker G, Bockeria LA, Sadowski J, Schmitz C, Kapelak B, et al. Sutureless aortic valve replacement with the Trilogy Aortic Valve System: multicenter experience. J Thorac Cardiovasc Surg 2010;140:878-84.

6) Di Eusanio M, Fortuna D, De Palma R, Dell’Amore A, Lamarra M, Contini GA, et al. Aortic valve replacement: results and predictors of mortality from a contemporary series of 2256 patients. J Thorac Cardiovasc Surg 2011;141:940-7.

7) St Rammos K, Ketikoglou DG, Koullias GJ, Tsomkopoulos SG, Rammos CK, Argyrakis NP. The Nicks-Nunez posterior enlargement in the small aortic annulus: immediateintermediate results. Interact Cardiovasc Thorac Surg 2006;5:749-53.

8) Dhareshwar J, Sundt TM, Dearani JA, Schaff HV, Cook DJ, Orszulak TA. Aortic root enlargement: what are the operative risks? J Thorac Cardiovasc Surg 2007;134:916-24.

9) Kohl P, Wijns W, Danchin N, Di Mario C, Falk V, Folliguet T, et al. Guidelines on myocardial revascularization. Eur J Cardiothorac Surg 2010;38:1–52.

10) Martens S, Sadowski J, Eckstein FS, Bartus K, Kapelak B, Sievers HH, et al. Clinical experience with the ATS 3f Enable® Sutureless Bioprosthesis. Eur J Cardiothorac Surg 2011;40:749-55.

11) Borger MA, Carson SM, Ivanov J, Rao V, Scully HE, Feindel CM, et al. Stentless aortic valves are hemodynamically superior to stented valves during midterm follow-up: a large retrospective study. Ann Thorac Surg 2005;80:2180-5.

12) Minh TH, Mazine A, Bouhout I, El-Hamamsy I, Carrier M, Bouchard D, et al. Expanding the indication for sutureless aortic valve replacement to patients with mitral disease. J Thorac Cardiovasc Surg 2014;148:1354-9.

13) Folliguet TA, Laborde F, Zannis K, Ghorayeb G, Haverich A, Shrestha M. Sutureless perceval aortic valve replacement: results of two European centers. Ann Thorac Surg 2012;93:1483-8.

14) Pollari F, Santarpino G, Dell’Aquila AM, Gazdag L, Alnahas H, Vogt F, et al. Better short-term outcome by using sutureless valves: a propensity-matched score analysis. Ann Thorac Surg 2014;98:611-6.

15) Ranucci M, Frigiola A, Menicanti L, Castelvecchio S, de Vincentiis C, Pistuddi V. Aortic cross-clamp time, new prostheses, and outcome in aortic valve replacement. J Heart Valve Dis 2012;21:732-9.

16) D’Onofrio A, Rizzoli G, Messina A, Alfieri O, Lorusso R, Salizzoni S, et al. Conventional surgery, sutureless valves, and transapical aortic valve replacement: what is the best option for patients with aortic valve stenosis? A multicenter, propensity-matched analysis. J Thorac Cardiovasc Surg 2013;146:1065-70.

17) Dağdelen S, Karabulut H, Şenay Ş, Akyol A, Toraman F, Çağıl H, et al. Transcatheter aortic valve implantation in patients with high-risk aortic stenosis: a clinical follow-up. Turk Gogus Kalp Dama2011;19:495-502.

18) Wiesenack C, Liebold A, Philipp A, Ritzka M, Koppenberg J, Birnbaum DE, et al. Four years' experience with a miniaturized extracorporeal circulation system and its influence on clinical outcome. Artif Organs 2004;28:1082-8.

19) Baikoussis NG, Papakonstantinou NA, Apostolakis E. The “benefits” of the mini-extracorporeal circulation in the minimal invasive cardiac surgery era. J Cardiol 2014;63:391-6.

20) van Boven WJ, Gerritsen WB, Zanen P, Grutters JC, van Dongen HP, Bernard A, et al. Pneumoproteins as a lungspecific biomarker of alveolar permeability in conventional on-pump coronary artery bypass graft surgery vs miniextracorporeal circuit: a pilot study. Chest 2005;127:1190-5.

21) Zakkar M, Guida G, Suleiman MS, Angelini GD. Cardiopulmonary bypass and oxidative stress. Oxid Med Cell Longev 2015;2015:189863.

22) Johnston DR, Soltesz EG, Vakil N, Rajeswaran J, Roselli EE, Sabik JF, et al. Long-term durability of bioprosthetic aortic valves: implications from 12,569 implants. Ann Thorac Surg 2015;99:1239-47.

23) Suri RM, Michelena HI, Burkhart HM, Greason KL, Daly RC, Dearani JA, et al. A prospective, randomized comparison of 3 contemporary bioprosthetic aortic valves: should hemodynamic performance influence device selection? J Thorac Cardiovasc Surg 2012;144:1387-95.

24) Coutinho GF, Correia PM, Paupério G, de Oliveira F, Antunes MJ. Aortic root enlargement does not increase the surgical risk and short-term patient outcome? Eur J Cardiothorac Surg 2011;40:441-7.