Aortic valve reimplantation in ascending aortic aneurysm: risk factors for early valve failure

Aortic valve sparing operations: a review

Aortic valve sparing operations were developed to preserve the native aortic valve during surgery for aortic root aneurysm as well as surgery for ascending aortic aneurysms with associated aortic insufficiency. There are basically two types of aortic valve sparing oprations: remodeling of the aortic root and reimplantation of the aortic valve. These operations have been performed for over two decades and the clinical outcomes have been excellent in experienced hands. Although remodeling of the aortic root is physiologically superior to reimplantation of the aortic valve, long-term follow-up suggests that the latter is associated with lower risk of developing aortic insufficiency. Failure of remodeling of the aortic root is often due to dilatation of the aortic annulus. Thus, this type of aortic valve sparing should be reserved for older patients with ascending aortic aneurysm and normal aortic annulus whereas reimplantation of the aortic valve is more appropriate for young patients with inherited disorders that cause aortic root aneurysms. This article summarizes the published experience with these two operations. They are no longer experimental procedures and should be part of the surgical armamentarium to treat patients with aortic root aneurysm and ascending aortic aneurysms with associated aortic insufficiency.

Long-term results after aortic valve-sparing operation (David I)

OBJECTIVE

Aortic valve-sparing David procedure has gained broad acceptance. However, few long-term results have been published. We present our results.

METHODS

More than 450 David procedures have been performed in our institution so far. Of these, 126 patients were operated between July 1993 and December 2000. Median age was 57 (8-83) years and 46 (36.5%) were female. As many as 26 (20.6%) had Marfan syndrome, 21 (16.7%) had acute aortic dissection type A (AADA) and 67 (53.2%) had additional procedures.

RESULTS

There were six (4.8%) deaths in 30 post-operative period (POD), four of whom had AADA. In the follow-up, there were 32 (25.4%) late deaths, 11 (34.4%) of these were caused by cardiac or underlying disease or op-related. As many as 15 (11.9%) patients were re-operated; six (40%) were Marfan patients and two (13.3%) had early endocarditis. Follow-up echocardiography of 76 (60.3%) event-free patients showed valve insufficiency (AI)≤AI I° in 68 (89.5%) and grade II in 7 (9.2%) patients. Leaflet degeneration due to proposed leaflet contact with the straight Dacron graft was not observed. A total of 36 (47.4%) patients were in New York Heart Association (NYHA) class I, 33 (43.4%) in NYHA II, and five (6.6%) were in class III. During the entire follow-up of 790 patient-years, there was no stroke or major bleeding. Survival at 1, 5 and 10 years was 93%, 85% and 70%, respectively. Freedom from valve replacement at 1, 5 and 10 years was 96%, 91% and 87%, respectively.

CONCLUSIONS

Regardless of the underlying pathology, valve-sparing David I procedure has acceptable long-term results. Valve-related complications such as stroke or major bleeding is exceedingly low.

Valve-sparing aortic root replacement

The aortic root has a unique 3-dimensional configuration and the distinctive function of supporting the aortic valve and blood vessels. The sinuses of Valsalva are crucial to create appropriate eddy currents that are important in initiating and coordinating aortic valve closure and promoting coronary artery blood flow. Most aneurysms in the aortic root are associated with degenerative changes in the elastic media rather than atherosclerosis. Valve-sparing root repair has become widely accepted, although the Bentall procedure remains the gold standard. Because reimplantation using the Valsalva graft allows root geometry to be retained and theoretically and practically prevents recurrent aortic valve regurgitation, it is considered the most reliable and preferred technique among various valve-sparing aortic root repair procedures.

Aortic regurgitation after valve-sparing aortic root replacement: modes of failure

BACKGROUND

Despite the positive clinical results of valve-sparing aortic root replacement, little is known about the causes of reoperations and the modes of failure.

METHODS

From October 1999 to June 2010, 101 patients underwent valve-sparing aortic root replacement using the David reimplantation technique. The definition of aortic root repair failure included the following: (1) intraoperative conversion to the Bentall procedure; (2) reoperation performed because of aortic regurgitation; and (3) aortic regurgitation equal to or greater than a moderate degree at the follow-up. Sixteen patients were considered to have repair failure. Three patients required intraoperative conversion to valve replacement, 3 required reoperation within 3 months, and another 8 required reoperation during postoperative follow-up. At initial surgery 5 patients had moderate to severe aortic regurgitation, 6 patients had acute aortic dissections, 3 had Marfan syndrome, 2 had status post Ross operations, 3 had bicuspid aortic valves, and 1 had aortitis. Five patients had undergone cusp repair, including Arantius plication in 3 and plication at the commissure in 2.

RESULTS

The causes of early failure in 6 patients included cusp perforation (3), cusp prolapse (3), and severe hemolysis (1). The causes of late failure in 10 patients included cusp prolapse (4), commissure dehiscence (3), torn cusp (2), and cusp retraction (1). Patients had valve replacements at a mean of 23 ± 20.9 months after reimplantation and survived.

CONCLUSIONS

Causes of early failure after valve-sparing root replacement included technical failure, cusp lesions, and steep learning curve. Late failure was caused by aortic root wall degeneration due to gelatin-resorcin-formalin glue, cusp degeneration, or progression of cusp prolapse.

Preoperative aortic root geometry and postoperative cusp configuration primarily determine long-term outcome after valve-preserving aortic root repair

OBJECTIVE

Technical controversies exist in valve-preserving aortic root replacement. We sought to determine predictors of long-term stability of the aortic valve.

METHODS

A total of 430 patients (aged 57 ± 15 years, 323 male) underwent valve-preserving aortic root surgery (remodeling in 401, reimplantation in 29) between 1995 and 2009 and were followed echocardiographically. Factors influencing late recurrence of aortic valve regurgitation grade II or greater (n = 45) or need for reoperation on the aortic valve (n = 25) were analyzed.

RESULTS

Early mortality was 2.8% (1.9% for elective cases), and actuarial survival at 10 years was 83.5% ± 2.4%. Ten-year freedom from aortic valve regurgitation grade II or greater was 85.0% ± 2.5%. Preoperative aortoventricular junction diameter greater than 28 mm and postoperative effective height of the aortic cusp less than 9 mm were identified as significant predictors for late aortic valve regurgitation grade II or greater in multivariate analysis (both P < .001). Ten-year freedom from reoperation on the aortic valve was 89.3% ± 2.5%. Preoperative aortoventricular junction diameter greater than 28 mm (P < .001), use of pericardial patch (P = .022), and effective height of the aortic cusp less than 9 mm (P = .049) were identified as significant predictors for reoperation in multivariate analysis. Operative technique (remodeling, reimplantation), Marfan syndrome, bicuspid valve anatomy, concomitant central cusp plication, size of prosthesis used, and acute dissection were not associated with an increased risk of late aortic valve regurgitation grade II or greater or reoperation. In patients with preoperative aortoventricular junction diameter greater than 28 mm (n = 94), the addition of central cusp plication significantly improved freedom from aortic valve regurgitation grade II or greater (P = .006) regardless of root procedures (remodeling, P = .011; reimplantation, P = .053).

CONCLUSIONS

Long-term stability of valve-preserving aortic root replacement was influenced not by the technique of root repair but by the preoperative aortic root geometry and postoperative cusp configuration.

Aortic valve-sparing operations: state of the art

PURPOSE OF REVIEW

Aortic valve-sparing (AVS) operations include an armamentarium of procedures, which preserve the aortic cusps in aortic root dilation with aortic insufficiency. The purpose of this review article is to specifically outline the surgical indications, to describe the various techniques, and to present results from the most current series in AVS operations.

RECENT FINDINGS

In the worldwide literature, there is promising data on AVS operations. Patients undergoing AVS operations not only have better long-term survival but also appear to have a reduced risk of aortic insufficiency and thromboembolic complications.

SUMMARY

AVS operations are an excellent option for patients with an aortic root aneurysm and normal/minimally diseased aortic cusps.

Advances in aortic valve repair: focus on functional approach, clinical outcomes, and central role of echocardiography

The surgical classification of aortic regurgitation (AR) is based on cusp mobility. Based on this classification, there are 3 classes of AR: type I is defined as normal cusp mobility, type II is defined as excessive cusp mobility, and type III is defined as restricted cusp mobility. Patients often have multiple coexisting mechanisms. Because aortic valve (AV) repair is safe, effective, and durable, it likely will become a mainstream surgical option for the management of significant AR, even in the setting of a bicuspid valve. Intraoperative transesophageal echocardiography has a central role at all stages in AV repair. Before cardiopulmonary bypass, it can accurately diagnose the mechanism of AR to guide operative strategy for successful repair. After separation from cardiopulmonary bypass, it can comprehensively evaluate the AV repair, including the likelihood that the repair will be durable in the long-term. Important echocardiographic predictors of a durable AV repair include the absence of AR, cusp coaptation above the annular plane, a coaptation length >4 mm, and an effective cusp height >8 mm. The clinical applicability of AV repair continues to expand and likely will evolve into a mainstream surgical therapy for AR, including minimally invasive techniques.

Valve-sparing aortic root reconstruction

The aortic valve-sparing root reconstruction procedure remains an ideal concept, but it has not yet become an ideal operation. There is still great variation and evolution in techniques, which mirrors the increasing understanding of the aortic root's functional anatomy and the disease processes that affect it. These operations remain complex, and the surgeons who perform them well are often times best armed with an experienced eye for what looks right more than a mathematical model that can predetermine who will do well, with what repair type and with what percentage chance of long-term success. Because of this, it will likely still be a while before these operations are more routinely used by a broader group of surgeons, as compared with the very reproducible Bentall and De Bono repair.

Right coronary sinus fixation through a right ventriculotomy for David's procedure

A key element to the success of aortic valve reimplantation (David's procedure) is the position of the aortic annulus in the Dacron tube (DuPont, Wilmington, DE). The variable level of the right ventricular insertion can cause technical difficulties, especially when the right ventricular insertion occurs above the aortic annulus. To resolve this issue, a technical adjunct is described using a right superior ventriculotomy. This technique allows perfect aortic annulus containment, avoids any rocking motion of the margin of the right coronary cusp, and affords the procedure better long-term durability.

Sinotubular Junction Size Affects Aortic Root Geometry and Aortic Valve Function in the Aortic Valve Reimplantation Procedure: An In Vitro Study Using the Valsalva Graft

BACKGROUND

Sinotubular junction (STJ) size in aortic valve reimplantation procedures is usually predetermined on the basis of experience or intraoperative mathematical calculations. Given the small coaptation reserve of aortic valve leaflets, small errors can produce an incompetent aortic valve. We tested in vitro the effect of geometrically changing the relationship between aortic annulus size and STJ size on aortic root geometry and aortic valve function.

METHODS

Twenty-five-millimeter diameter scalloped porcine aortic roots were reimplanted into 32-mm Valsalva grafts (Vascutek, Renfrewshire, Scotland), suspending commissures into the expandable region of the graft itself. Neoaortic roots were pressurized up to 100 mm Hg. Sinotubular junction size was then changed by wrapping the neocommissural ridge with Dacron rings of decreasing size. Geometry of the aortic root, anatomy of aortic valve leaflets, and extent of their coaptation were analyzed by direct endoscopic view and by ultrasound imaging techniques.

RESULTS

Pressurizing unwrapped aortic root resulted in centrifugal displacement of commissures, aortic leaflets tethering and bending, and central aortic regurgitation. By reducing STJ size, coaptation height of aortic valve leaflets first increased to reach a maximum for an STJ size corresponding to 30 mm, and then decreased for further reduction of STJ size. Excess reduction of STJ size also resulted in prolapsed aortic leaflets and eccentric aortic regurgitation.

CONCLUSIONS

In the reimplantation procedure performed with a Valsalva graft, aortic valve function and leaflet coaptation can be optimized by optimizing STJ size.

Aortic root remodeling: Ten-year experience with 274 patients

OBJECTIVES

Dilatation of the aortic root with concomitant aortic regurgitation can be treated by valve-preserving surgery. We have consistently chosen root remodeling rather than reimplantation whenever the aortoventricular junction was not dilated. We have analyzed our 11-year experience with root remodeling.

METHODS

Between October 1995 and October 2006, 274 patients (201 male; 73 female, aged 59 +/- 15 years) were treated by root remodeling in the presence of a preserved aortoventricular diameter (<30 mm). Acute aortic dissection was present in 46 patients. The valve anatomy was tricuspid in 193 and bicuspid in 81 patients. Cusp disease was additionally corrected in 173 (63%) patients. Follow-up was complete in 99%. Cumulative follow-up was 1045 patient-years (mean of 4.0 +/- 2.7 years).

RESULTS

Hospital mortality was 3.6% (elective 3.1%; emergency 6.5%). One patient had endocarditis 2 months postoperatively and subsequently underwent valve replacement. Freedom from aortic regurgitation of grade II or more was 91% and 87% at 10 years for bicuspid and tricuspid aortic valves. Nine patients required reoperation: in 6 patients the valve was replaced and in 3 patients rerepaired. Freedom from reoperation was 96% at 5 and 10 years, and freedom from valve replacement was 98% at 5 and 10 years. A comparison of 3 operative periods (1995-1998, 1999-2002, and 2003-2006) showed that with increasing experience cusp prolapse was diagnosed and corrected more frequently (8/49 = 17%; 62/105 = 59%; 103/108 = 82%; P < .0001), and repair stability significantly improved over time (P = .007).

CONCLUSIONS

Root remodeling leads to durable restoration of aortic valve function in both tricuspid and bicuspid valve anatomy. Aggressive correction of cusp prolapse seems to have a beneficial effect on aortic valve competence.

Aortic Valve Repair: The Functional Approach to Leaflet Prolapse and Valve-Sparing Surgery

BACKGROUND

Combined aortic valve repair and aortic valve-sparing surgery requires an approach determined by the leaflets and aortic root anatomy.

METHODS

Among patients referred for aortic root aneurysm, 114 patients underwent an aortic valve-sparing procedure in which a reimplantation or remodelling technique was used. The Gelweave Valsalva prosthesis (Sulzer Vascutek, Renfrewshire, UK) was used in 45 patients. Better molding of the prosthesis on the aortic annulus was achieved by a low proximal dissection and incisions on the prosthesis to respect the anatomy of the aortoventricular junction. The reimplantation technique was used in 58%, and 62% of all patients underwent an associated leaflet procedure.

RESULTS

The operative mortality rate was 1%, with a 2% immediate reoperation rate. During the mean follow-up 50 +/- 35 months, 3 patients (2.6%) needed reoperation for recurrent aortic regurgitation (n = 2) or aortic stenosis (n = 1). At the end of follow-up, aortic regurgitation grade exceeding 2 had occurred in 2.6% of patients (n = 3), and 98.2% were in New York Heart Association functional class 1 or 2. Neither the early nor mid-term results showed any differences among the different surgical techniques used (reimplantation, remodeling, Valsalva prosthesis, additional leaflet repair).

CONCLUSIONS

A complete approach to the different components of the aortic root allows good clinical results at mid-term.

Preservation of the Bicuspid Aortic Valve

BACKGROUND

Bicuspid anatomy of the aortic valve is a common reason for aortic regurgitation and is associated with aortic dilatation in more than 50% of patients. We have observed different patterns of aortic dilatation and used different approaches preserving the valve.

METHODS

Between October 1995 and February 2006, a regurgitant bicuspid valve was repaired in 173 patients. The aorta was normal in 57 patients who underwent isolated repair. Aortic dilatation mainly above commissural level (n = 38) was treated by separate valve repair plus supracommissural aortic replacement. In 78 patients, aortic dilatation involved the root and was treated by root remodeling.

RESULTS

Hospital mortality and perioperative morbidity were low in all three groups. Myocardial ischemia was significantly shorter in repair plus aortic replacement than remodeling (p < 0.001). Freedom from aortic regurgitation II or greater at 5 years varied between 91% and 96%. Freedom from reoperation at 5 years was 97% after remodeling, but only 53% after repair plus aortic replacement (p = 0.33). Symmetric prolapse was the most frequent cause for reoperation.

CONCLUSIONS

The long-term stability of bicuspid aortic valve repair is excellent in the absence of aortic pathology. In the presence of aortic dilatation, root remodeling leads to equally stable valve durability. In patients with less pronounced root dilatation, separate valve repair plus aortic replacement may be a less complex alternative. Symmetric prolapse should be avoided if the ascending aorta is replaced.

Aortic Valve–Sparing Operation in Marfan Syndrome: What Do We Know After a Decade?

BACKGROUND

We assessed the outcome in patients with Marfan syndrome operated on exclusively with the aortic valve-sparing reimplantation technique for aortic root aneurysms during more than a decade.

METHODS

Between July 1993 and April 2005, the aortic valve-sparing reimplantation technique (David I) was used in 325 patients. In 59 patients with clinical evidence of Marfan syndrome, procedures were done for aortic root aneurysm (n = 55) or aortic dissection type A (n = 4). Their mean age was 30 +/- 12 years (range, 9 to 62 years), and 37 (63%) were male. Additional procedures were arch replacement in 4 patients, coronary artery bypass grafting in 1, mitral valve surgery in 9, and closure of atrial septal defect in 3. Mean follow-up was 54 +/- 37 months (range, 0 to 139 months).

RESULTS

No patient died during the first 30 days postoperatively. Mean bypass time was 163 +/- 34 minutes (range, 99 to 248 minutes), and mean aortic cross clamp time was 126 +/- 28 minutes (range, 78 to 202 minutes). Four patients (6.8%) required rethoracotomy for postoperative bleeding. Five late deaths (8.5%) occurred during follow-up. Reoperation of the reconstructed valve was required in 7 patients. Freedom from reoperation was 88% +/- 5% at 5 years and 80% +/- 9% at 10 years. Mean grade of aortic insufficiency was 1.81 preoperatively compared with 0.20 early postoperatively (p < 0.001). At last investigation, the mean grade of aortic insufficiency increased slightly to 0.22 (p = 0.16). Anticoagulation was not required in 67% of patients. One thromboembolic complication and four instances of minor bleeding were documented. All patients were in New York Heart Association functional class I (86%) or II at last contact.

CONCLUSIONS

Excellent early outcome, favorable long-term results, and acceptable durability of the reimplanted valve should encourage use of this technique in patients with Marfan syndrome.

Valve-sparing aortic root replacement: the inclusion (David) technique

Presentation of the aortic valve reimplantation technique (David I): Removal of the diseased ascending aorta, excision of the coronary ostia and resection of aortic sinuses up to a rim of 2-3 mm of aortic wall as well as extensive external dissection and mobilization of the aortic root; placement of horizontal sutures placed circumferentially through the annulus underneath the valve; anchoring a Dacron-graft in the aortic root with the sutures; fixation of commissures high into the tube graft; reimplantation of the sinuses into the graft with a blood-tight running suture line; reimplantation of coronary buttons; establishment of distal aortic anastomosis.

Reoperations on the Ascending Aorta and Aortic Root in Patients With Previous Cardiac Surgery

BACKGROUND

First time operations on the ascending aorta are performed with low mortality, few complications, and excellent long-term results. Reoperations for aortic pathology in patients with previous cardiac surgery carry significantly more risk. Technical issues during the procedure, as well as age, preoperative New York Heart Association class, and perioperative renal dysfunction, have been shown to contribute heavily to worse outcomes. We analyzed our results with aortic reoperations with the intent of further reducing surgical risk through alterations in surgical technique or patient selection.

METHODS

From July 1997 until October 2005, 147 patients having previous cardiac surgery presented with aneurysm or dissection of the ascending aorta or root. Perioperative data were retrospectively analyzed. Morbidity, mortality, and risk factors for these events were calculated.

RESULTS

Eight patients expired (5.4%) after their reoperation. Significant (p < 0.05) univariate risk factors for mortality included age greater than 75 years (< 0.001), previous coronary artery bypass grafting (CABG) (< 0.008), cardiopulmonary bypass greater than 240 minutes (< 0.01), need for intraaortic balloon pump support (< 0.001), need for new CABG (< 0.007), postoperative cerebrovascular accident (< 0.032), and tracheostomy (< 0.003). Age 75 years or older (p < 0.025) was the only significant variable for death by multivariate analysis. A majority of patients (n = 87, 60%) required circulatory arrest to complete their procedure. However, neither arch involvement nor type of aortic root procedure was predictive of perioperative mortality.

CONCLUSIONS

Surgery on the ascending aorta and root in patients who have had previous cardiac surgery can be performed with low mortality. Advanced age and significant coronary disease may negatively influence surgical results.

Evaluation of native valve-sparing aortic root reconstruction with direct imaging--reimplantation or remodeling?

BACKGROUND

Aortic root reimplantation and remodeling have been used to preserve the native aortic valve. However, direct observation of valve motions with these techniques has not been performed.

METHODS

Mongrel dogs were studied. The beating heart model was created using modified Tyrode's solution. Normal aortic valves and aortic valves preserved with the remodeling or reimplantation procedure were observed with an endoscope, and behavior was recorded on a high-speed video (200 frames/s). The aortic valve orifice area was measured at 11 data points per beat. A predictable maximum valve orifice area was defined as an area encircled by the three commissures. A ratio of each aortic valve orifice area to the predictable maximum valve orifice area was calculated. The control group, the reimplantation group, and the remodeling group were compared.

RESULTS

The preserved aortic valve with reimplantation showed bending and asymmetric motion. The ratio of aortic valve orifice area and predictable maximum valve orifice area in the reimplantation group was significantly smaller compared with the control and remodeling groups.

CONCLUSIONS

The opening and closing behavior of the aortic valve preserved with the reimplantation procedure was impaired. It was speculated that the remodeling procedure may preserve more physiologic root function compared with the reimplantation procedure.

Correction of leaflet prolapse in valve-preserving aortic replacement: pushing the limits?

BACKGROUND

For aortic dilatation with morphologically intact leaflets, valve-preserving aortic replacement has become an accepted treatment modality. Leaflet prolapse, however, may be present, making composite replacement the most frequent choice. Alternatively, valve preservation may be combined with correction of leaflet prolapse. The results of this approach should be comparable with those of valve-preserving aortic surgery in the presence of normal leaflets.

METHODS

Between 1995 and 2002, 156 patients were treated by valve-preserving surgery. The aortic valve was bicuspid in 46, and tricuspid in 110 instances. In 88 aortic valves, apparently normal leaflet coaptation (normal, 12 bicuspid and 76 tricuspid), and in 68 instances, prolapse of one or more leaflets, was observed. Root remodeling (n = 133) or aortic replacement with valve reimplantation (n = 23) were performed. Leaflet prolapse was corrected by triangular resection (n = 16) or plicating sutures (n = 59), mostly placed in the central portion of the leaflet.

RESULTS

Neither operative mortality nor 5-year survival were influenced by the additional correction of prolapse. Freedom from reoperation at 1 year (normal, 98.8%; prolapse, 96.5%) and 5 years (normal, 97.3%; prolapse, 96.5%) were comparable in both cohorts, as was freedom from aortic regurgitation > or = II at 1 year (normal, 98.8%; prolapse, 94.2%) and 5 years (94.4%).

CONCLUSIONS

Surgical correction of leaflet prolapse in combination with proximal aortic replacement is feasible with good results. Midterm results are identical with those known for morphologically normal leaflets. Repair of prolapse allows for preservation of the native valve in most patients with aortic regurgitation and aortic pathology, and thus appears a beneficial addition to valve-preserving surgery.