Valve-sparing root replacement: surgical technique

Introduction

Thoracic aortic aneurysms (TAAs) have an incidence of 5–10 per 100,000 person-years (1) and aortic root aneurysms are the most common type of TAAs, making up almost 60% of all TAAs (1-3). Aortic root aneurysms are defined as full-thickness dilations of the aortic root of 4.5 cm diameter or greater, occurring between the aortic valve annulus and the sinutubular junction (STJ) (3). Aortic root aneurysms tend to have a heritable influence, including connective tissue disorders such as Marfan and Loeys-Dietz syndromes, and, as such, patients with aortic root aneurysms present earlier (at 60 years respectively) than those patients with sporadic aortic root aneurysms (64 years); patients with aortic root aneurysms also present earlier than those with descending TAAs (72 years) (2-4). Aortic root aneurysms may be associated with bicuspid aortic valves, which may have a heritable component, although the majority are sporadic (5). The typical acquired risk factors for sporadic degenerative TAAs, such as diabetes, hypertension, atherosclerosis, and smoking are less common in aortic root aneurysm patients than in sporadic ascending and descending TAA patients (2,6). The natural history and management of aortic root aneurysm varies with the presence or absence of family history, a heritable component, or bicuspid aortic valve. The majority of aortic root aneurysms are asymptomatic (2,3). However, if left untreated, these may result in acute aortic syndromes such as dissection or rupture.

Traditional surgical management of aortic root aneurysmal dilatation was aortic root replacement surgery with a composite valve-graft (7). The valve portion of the valve graft may be mechanical or bioprosthetic valves (7). Aortic root replacement for patients who have both aortic valve and aortic root pathology is the appropriate surgical intervention (3). However, regurgitation or dysfunction of the aortic valve may be related to annuloaortic ectasia, or dilatation of the sinuses of Valsalva or the STJ, rather than intrinsic disease or anomaly of the aortic valve leaflets themselves (7,8). In addition, connective tissue disorders such as Marfan and Loeys-Dietz syndromes, or other diseases leading to aortic root aneurysms spare the aortic valve leaflets, which have different developmental cell lineage, while leading to aortic aneurysmal disease (7). In patients with healthy aortic valve leaflets but aortic root disease, the development of an aortic valve-sparing technique represents the ideal solution, as preservation of the native valve leaflets avoids both the inevitable structural degeneration associated with the use of bioprosthetic vales as well as the need for lifelong anticoagulation associated with the use of mechanical valves.

Valve-sparing root replacement (VSRR) with the reimplantation technique was first described by Dr. Tirone David in 1992 (8). Dr. David described resecting the aneurysmal aorta, followed by reimplanting the whole aortic valve apparatus into a tubular Dacron graft (8). With proper sizing of tube graft diameter, reimplantation restores the geometry to the aortic valve itself, to the annulus, and to the STJ, thereby restoring proper valve function. The following text and video describe the technical aspects of VSRR (Video 1). We present this article in accordance with the SUPER reporting checklist (available at https://asj.amegroups.com/article/view/10.21037/asj-24-16/rc)

Preoperative preparations and requirements

Our institution, Weill Cornell Medicine, is a tertiary academic center with ample support staff and assistance in the operative room to perform complex aortic operations. VSRR is performed as a sterile procedure in the operating room.

The surgical team includes the attending cardiothoracic surgeon, trained surgical assistants such as a fellow (or resident) of cardiothoracic surgery and a physician assistant. Other team members include a cardiac critical care-trained anesthesiologist, a perfusionist, a scrub nurse, and a circulating nurse.

Surgical intervention for aortic root aneurysms is based on guidelines of the American College of Cardiology/American Heart Association (3) and is indicated in all patients with symptoms, in asymptomatic patients who have a maximum aortic root or ascending aortic diameter of ≥5.5 cm, in patients with an aneurysm of the aortic root or ascending aorta with a growth rate of ≥0.5 cm in one year, or in asymptomatic patients with aneurysms ≥5.0 cm, if repair is performed by an experienced surgeon as part of a multidisciplinary aortic team (3). VSRR is indicated for patients undergoing aortic root replacement if the aortic valve is suitable for sparing or repair (no large fenestrations, no calcifications, intact valve leaflets), and can be performed using either the reimplantation or the remodeling technique (3).

Recipients of VSRR include all patients meeting the above criteria. The majority of these patients are male, presenting at a mean age of approximately 64 years old (2,7). The majority of patients present with sporadic aortic root aneurysms, however, there is a strong heritable component to aortic root aneurysms, and patients may have a family history of aortic aneurysm, dissection, or rupture. Patients with connective tissue disorders (Marfan, Loeys-Dietz), among others, may have intact aortic valve leaflets in the presence of aneurysmal disease. Preoperative testing includes at least a history and physical exam, routine preoperative labs, cross-sectional imaging of the aortic root (computed tomography angiography), as well as echocardiogram. Informed consent must be obtained, and patients should have an understanding of the surgical risks, benefits, possible adverse events, and expected postoperative course.

The patient is positioned supine on the operating table. Adequate intravenous access is achieved (16–18 gauge intravenous lines). After induction and endotracheal intubation, central venous access, Swan-Ganz catheter, and arterial line are placed. Blood products are available in the operating room prior to procedure start. Sterile skin preparation with chlorhexidine solution is performed. Foley catheter is placed. Prophylactic antibiotics are administered. Preoperative transesophageal echocardiography (TEE) is performed to further assess valve function and anatomy.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this manuscript and the accompanying video. A copy of the written consent is available for review by the editorial office of this journal.

Step-by-step description

Median sternotomy from sternal notch to xiphoid is created with a reciprocating saw. The pericardium is opened longitudinally. At this point, heparin is administered, cannulation is performed using an aortic cannula in the arch and venous cannula in the right atrium, and the patient is placed on cardiopulmonary bypass, maintaining flow at 2.4 liters per minute per meter squared and mean arterial pressure at 80 mmHg. The patient is then cooled to 32 ℃. Antegrade cold blood potassium cardioplegia (St. Thomas solution) is used to induce diastolic arrest, while iced saline slush is used for topical protection. Cardioplegia is administered into the aortic root in patients without aortic insufficiency (AI), and by direct ostial injection into the coronary arteries in patients with AI. Cardioplegia is then readministered every 25–30 minutes, maintaining temperature lower than 10 ℃.

Once cardioplegic arrest is established, the ascending aorta is resected down to the STJ. Initial assessment of the valve leaflets’ suitability for preservation is performed. Ideal leaflets are thin and pliable without major calcification, fenestrations, or perforations. The aorta is separated from the pulmonary artery. The aorta is resected to within 3 to 4 mm of the annulus starting in the non-coronary sinus. Coronary buttons are cut from the surrounding aortic tissues using vertical incisions on either side of the button and a horizontal connecting incision at the nadir. This results in a rectangular shape, which helps with orientation and preventing twisting. A plane is developed circumferentially around the aortic annulus down to the level of the left ventricular outflow tract, below the level of the annulus. The ligament between the aorta and pulmonary artery at the left-right commissure is carefully taken down, however, other groups may make a small opening in the prosthetic graft to allow a space through which the ligament may pass.

A Hegar dilator is used to size the annulus. Twelve non-pledgeted Ethibond (Ethicon, Raritan, NJ, USA) sutures are placed in a single horizontal plane through the left ventricular outflow tract. These are placed below the level of the annulus, starting at the commissures and then evenly spaced between the commissures. Some groups use pledgeted sutures, but we have not found this to be necessary and it adds prosthetic material to the left ventricular outflow tract. A sinus of Valsalva graft (Terumo Aortic, Sunrise, FL, USA) has been adopted by our institution, as the pliable fabric, the added space in the preformed sinus segment, and the predefined STJ yield improved visualization and reproducible results. A graft 3–5 mm larger than the Hegar dilator sizer, up to a maximum of 32 mm, is selected. Patients with annular diameter larger than this are downsized to a 32-mm graft. The height of the commissure is measured from the aorto-mitral curtain to the top of the left-non commissure. The height of the commissure is marked on the graft from the neo-STJ towards the annulus. The excess length on the skirt of the Valsalva graft is trimmed. The commissures are drawn onto the graft as well as the approximate suture line for reimplantation, which is used as a guide while suturing within the graft later. It is important to maintain a “U” shape and prevent a “V” shaped reimplantation suture line as this can distort the valve, leading to AI. The valve sutures are passed through the graft at the neo-annular level and then tied down with the Hegar dilator in place to prevent an inadvertent annuloplasty effect. The commissures are lifted up vertically at their natural angular configuration (usually 120–120–120 degrees in trileaflet valves or 150–210 or 180–180 degrees in bicuspid valves) and resuspended at the neo-STJ using pledgeted 4-0 polypropylene suture. The valve is then reimplanted with running 4-0 polypropylene suture, and the left main coronary button is reattached with 5-0 polypropylene.

The valve cusps are visually assessed for prolapse or excessive free edge length. A majority of AI is improved by correcting the root dilatation, whereas a minority of patients require leaflet modification. Cusp repair, most often using central plication, is performed as needed to achieve equal free edge length and proper coaptation. Although many groups prefer to repair the cusps prior to reimplantation within the graft, we prefer to have the commissural orientation established prior to measuring the cusps. The graft is pressurized with cardioplegia as we assess left coronary perfusion using a temperature monitor in the myocardium and monitor for AI. The distal anastomosis and then right coronary button reimplantation are subsequently performed. We prefer to reimplant the right coronary button as the last step because this allows us to assess positioning with better accuracy to prevent excessive kinking or stretching.

The patient is then placed in the Trendelenburg position, de-airing of the heart is carried out, and the aortic cross-clamp is removed. The patient is re-warmed to 36 ℃ and separated from cardiopulmonary bypass. Crossclamp times are approximately 100–125 minutes and cardiopulmonary bypass times are 120–150 minutes. Echocardiography is again performed to assess ventricular function and valvular function, in particular, for aortic valve insufficiency, stenosis, and to determine the aortic valve gradient. Additional indicators of future valve durability are assessed as well, such as coaptation length. If there is significant AI on the postoperative TEE and the mechanism of AI can be seen then an aortic valve repair can be attempted. However, if the valve cannot be repaired, the operation may be salvaged by aortic valve replacement performed within the graft. In cases where there is uncontrollable bleeding from an unclear source, aortic root replacement with a composite valve graft may be required as a rescue measure.

Protamine sulfate is administered for heparin reversal, and cannulas are removed. Then cannula sites are oversewn with 4-0 polypropylene sutures. Drainage tubes are placed in the mediastinum. The sternum is reapproximated with stainless-steel wires and subcutaneous tissues are reapproximated in layers in standard fashion.

Postoperative considerations and tasks

Postoperatively, patients are monitored in the Cardiothoracic Surgery Intensive Care Unit, with Swan-Ganz catheter, central venous lines, and arterial lines in place, and vasopressor support as needed. Early extubation, when safe, is encouraged, as is removal of central and arterial lines when close hemodynamic monitoring is no longer clinically warranted. Chest tubes are removed when output has sufficiently attenuated (less than 250 cc per day). Early mobilization is further encouraged, with the use of early ambulation by nursing staff and physical therapists as necessary, as is progressive diuresis with a goal of euvolemia, and an overall aim for hospital discharge within 5 days of surgery. Patients are seen for follow-up 2 weeks after hospital discharge, with postoperative imaging and subsequent annual follow-up.

Immediate postoperative success can be gauged by absence of immediate aortic valve insufficiency (or stenosis) and other major adverse events. Short-term outcomes after VSRR are excellent. In a recent analysis of VSRR at our institution, we found zero instances of in-hospital or early mortality in our VSRR cohort (9-11). The incidence of other early major adverse events (including operative mortality, myocardial infarction, stroke, re-exploration for bleeding, requirement for renal replacement therapy, and requirement for tracheostomy) was similarly low, with the most frequent event being re-exploration for bleeding (3% of patients). Other experienced centers have reported similar success in contemporary series, with operative mortality ranging from 1.1–4% (12-16).

Long-term success can be gauged by freedom from valve-related events including reoperation and AI, and by long-term survival. Recent series with long-term follow-up extending to 20 postoperative years have reported a low incidence of these outcomes as well, highlighting the durability and effectiveness of VSRR (7). David et al. reported that 69.1% of patients survived with freedom from aortic valve re-operation at 20 years. The cumulative risk of aortic valve reoperation was 6%, and the cumulative risk of moderate or severe AI was 10.2% (16). A recent series from our institution found that among 380 patients who underwent VSRR, 10-year survival was 97.4% in patients without connective tissue disease and 97.2% in patients with connective tissue disease, with no difference between propensity-matched groups, and freedom from reoperation of 93.5% in patients with connective tissue disease and 95.3% in patients without connective tissue disease (17). Other large series with ten to 15-year follow-up have reported similar outcomes, with 10- to 15-year survival ranging from 65% to 82.9%, freedom from reoperation ranging from 85% to 92.5%, and freedom from moderate or severe AI approaching 75% (12-14,16).

Tips and pearls

Appropriate patient selection is crucial to success of VSRR. Additional tips include the need to restore proper geometry to the entire aortic valve, annulus, and STJ, as this allows the valve to function properly without the need for valve replacement. Ensuring adequate dissection down to the annulus helps to avoid future failure of the repair due to dilatation of the annulus. Lastly, resuspension of the aortic valve is a critical step.

Discussion

Highlights of the VSRR technique include resection of the aneurysmal aortic tissue and reimplantation of the entire aortic valve within a Dacron tube-graft, thereby (with the use of the prior diameter of graft) restoring the appropriate geometry to the aortic valve, the annulus, and the STJ. This restoration of geometry allows for proper valve function while the native valve leaflets remain intact, making a highly durable repair. Distortion of the geometry may lead to immediate AI or premature valve degeneration upon follow-up. Several technical details are of vital importance. During dissection of the aortic root, the surgeon must ensure that dissection is carried down to the level of the annulus and left ventricular outflow tract. This allows the valve sutures to be passed through the left ventricular outflow tract and the base of the Dacron graft serves as a ring that prevents future annular dilatation, which is a mode of failure that the remodeling technique of VSRR is susceptible to. The next important step is resuspension of the valve in its natural position by lifting the commissure up vertically in the graft when deciding on their positioning. Additionally, when placing the running reimplantation sutures inside the sinuses, care must be taken to avoid the tendency to make a “V” shaped suture line but instead preserve a natural “U” shape to the sinus. Finally, adequate mobilization of the coronary buttons allows for flexibility in their placement when reimplanting on the graft in order to prevent overstretching or kinking and subsequent coronary ischemia.

The strengths of this technique compared with composite valve-grafts (and valve replacement) include the durability of reimplanted valves, which surpasses the durability of bioprosthetic valves, and the absence of the need for lifelong anticoagulation, which is required for mechanical valves. Propensity-matched comparisons of outcomes between VSRR and conduit valve-graft patients have found that results are comparable (12,18). In an aforementioned analysis of 890 consecutive aortic root replacement procedures at our institution, we found that surgical technique (mechanical composite valve graft, bioprosthetic composite valve graft, and VSRR) did not affect in-hospital mortality or long-term survival (10); while series from other centers have found superior durability in comparisons between VSRR and bioprosthetic composite valve grafts and lower risk of anticoagulation-related hemorrhage in comparisons between VSRR and mechanical composite valve grafts (12,18).

Conclusions

VSRR is an excellent aortic root replacement option, with short-term outcomes that are comparable to management with composite valve-grafts. Long-term outcomes after VSRR are similarly excellent, with improved durability compared with bioprosthetic composite valve grafts and lower lifelong risk of hemorrhage compared with mechanical composite valve grafts. In experienced, high-volume aortic centers, VSRR can be performed with low risk of mortality and complications.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the SUPER reporting checklist. Available at https://asj.amegroups.com/article/view/10.21037/asj-24-16/rc

Peer Review File: Available at https://asj.amegroups.com/article/view/10.21037/asj-24-16/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://asj.amegroups.com/article/view/10.21037/asj-24-16/coif). C.L. serves as an unpaid editorial board member of AME Surgical Journal from January 2023 to December 2026. L.H. received a T-32 grant from the National Heart, Lung, and Blood Institute (NHLBI) (grant number: 1-T32-HL16052001A1). The other author has no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient for publication of this manuscript and the accompanying video. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Clouse WD, Hallett JW Jr, Schaff HV, et al. Improved prognosis of thoracic aortic aneurysms: a population-based study. JAMA 1998;280:1926-9. [Crossref] [PubMed]
2. Vapnik JS, Kim JB, Isselbacher EM, et al. Characteristics and Outcomes of Ascending Versus Descending Thoracic Aortic Aneurysms. Am J Cardiol 2016;117:1683-90. [Crossref] [PubMed]
3. Isselbacher EM, Preventza O, Hamilton Black J 3rd, et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines. Circulation 2022;146:e334-482. [Crossref] [PubMed]
4. Mullan CW, Mori M, Bin Mahmood SU, et al. Incidence and characteristics of hospitalization for proximal aortic surgery for acute syndromes and for aneurysms in the USA from 2005 to 2014. Eur J Cardiothorac Surg 2020;58:583-9. [Crossref] [PubMed]
5. Bravo-Jaimes K, Prakash SK. Genetics in bicuspid aortic valve disease: Where are we? Prog Cardiovasc Dis 2020;63:398-406. [Crossref] [PubMed]
6. Elefteriades JA. Natural history of thoracic aortic aneurysms: indications for surgery, and surgical versus nonsurgical risks. Ann Thorac Surg 2002;74:S1877-80; discussion S1892-8. [Crossref] [PubMed]
7. Iannacone EM, Lau C, Jr Soletti G, et al. Aortic valve-sparing root replacement or Bentall? Ann Cardiothorac Surg 2023;12:168-78. [Crossref] [PubMed]
8. David TE, Feindel CM. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovasc Surg 1992;103:617-21; discussion 622. [Crossref] [PubMed]
9. Lau C, Wingo M, Rahouma M, et al. Valve-sparing root replacement in patients with bicuspid aortopathy: An analysis of cusp repair strategy and valve durability. J Thorac Cardiovasc Surg 2021;161:469-78. [Crossref] [PubMed]
10. Gaudino M, Lau C, Munjal M, et al. Contemporary outcomes of surgery for aortic root aneurysms: A propensity-matched comparison of valve-sparing and composite valve graft replacement. J Thorac Cardiovasc Surg 2015;150:1120-9.e1. [Crossref] [PubMed]
11. Ram E, Lau C, Dimagli A, et al. Valve Sparing vs Composite Valve Graft Root Replacement: Propensity Score-Matched Analysis. Ann Thorac Surg 2024;117:69-76. [Crossref] [PubMed]
12. Svensson LG, Rosinski BF, Tucker NJ, et al. Comparison of Outcomes of Patients Undergoing Reimplantation versus Bentall Root Procedure. Aorta (Stamford) 2022;10:57-68. [Crossref] [PubMed]
13. Shrestha M, Boethig D, Krüger H, et al. Valve-sparing aortic root replacement using a straight tube graft (David I procedure). J Thorac Cardiovasc Surg 2023;166:1387-1397.e10. [Crossref] [PubMed]
14. Manganiello S, Soquet J, Mugnier A, et al. David Procedure: A 21-year Experience With 300 Patients. Ann Thorac Surg 2023;115:1403-10. [Crossref] [PubMed]
15. Leshnower BG, Guyton RA, Myung RJ, et al. Expanding the indications for the David V aortic root replacement: early results. J Thorac Cardiovasc Surg 2012;143:879-84. [Crossref] [PubMed]
16. David TE, David CM, Ouzounian M, et al. A progress report on reimplantation of the aortic valve. J Thorac Cardiovasc Surg 2021;161:890-899.e1. [Crossref] [PubMed]
17. Ram E, Lau C, Dimagli A, et al. Long-term durability of valve-sparing root replacement in patients with and without connective tissue disease. J Thorac Cardiovasc Surg 2024;168:735-743.e2. [Crossref] [PubMed]
18. Ouzounian M, Rao V, Manlhiot C, et al. Valve-Sparing Root Replacement Compared With Composite Valve Graft Procedures in Patients With Aortic Root Dilation. J Am Coll Cardiol 2016;68:1838-47. [Crossref] [PubMed]