Commissural geometry and cusp fusion insights to guide bicuspid aortic valve repair

Predictors of long-term stenosis in bicuspid aortic valve repair

OBJECTIVES

The use of modern techniques for bicuspid aortic valve repair has been shown to provide safe and durable results against recurrent regurgitation. However, an emerging body of evidence is indicating that aortic stenosis might be an additional late complication of these procedures. To date, the pathogenesis and clinical impact of aortic stenosis after bicuspid aortic valve repair are poorly understood.

METHODS

A retrospective analysis of 367 patients with bicuspid aortic valve repair was performed to identify predictors of reoperation for stenosis. Bicuspid aortic valve repair was performed using a combination of procedures on the leaflet, annulus, and aortic root.

RESULTS

During a median follow-up of 8 years, reoperation for stenosis was required in 33 patients (9.0%). Freedom from reoperation for stenosis was 100%, 99.6%, 91.7%, and 74.9% at 1, 5, 10, and 15 years, respectively. The following factors were independently associated with reoperation for aortic stenosis: Leaflet or raphe resection with shaving was a protective factor (hazard ratio, 0.34; 95% confidence interval, 0.16-0.71; P = .004), whereas the use of expanded polytetrafluoroethylene for free-edge running suture (hazard ratio, 2.55; 95% confidence interval, 1.16-5.57; P = .019), supracoronary replacement of the ascending aorta in combination with valve repair (hazard ratio, 5.41; 95% confidence interval, 2.11-13.85; P = .001), and the need for a second aortic crossclamp (hazard ratio, 10.95; 95% confidence interval, 2.80-42.80; P = .001) were associated with increased risk of reoperation for aortic stenosis.

CONCLUSIONS

While confirming previous findings, our analysis suggests that the inability to restore leaflet mobility and polytetrafluoroethylene for free-edge running suture are risk factors for stenosis. The so-called ascending phenotypes are probably more prone to stenosis. If the first attempt to repair is unsuccessful, the risk of late reoperation for aortic stenosis is high.

Current controversies in aortic valve-preserving surgery

The clinical outcome of severe aortic regurgitation (AR) remains suboptimal, but surgery has been shown to have survival benefit over medical therapy. Postoperative survival is inferior in patients with reduced left ventricular function, and therefore early surgical intervention is recommended. Aortic valvuloplasty (AVP) is an attractive option to avoid the major drawbacks of prosthetic valves but has not been widely adopted. The etiology of AR is classified functionally into three groups: normal leaflet motion (type I), cusp prolapse (type II), and restriction (type III). Type I with dilatation of the sinus of Valsalva (type Ib) can be repaired by aortic valve reimplantation or aortic root remodeling with similar valve stability. Type I with dilatation of the aortic annulus (type Ic) can be managed by annuloplasty. Type II can be corrected by plication or resuspension techniques. Pericardial patch is necessary in AVP for type Id (perforation/fenestration) and type III but is associated with risk of recurrence. Bicuspid aortic valve is classified according to commissure angle: symmetrical, asymmetrical, and very asymmetrical. Tricuspidization is recommended for repair of very asymmetrical valves to avoid postoperative stenosis. Recent progress has achieved similar reoperation rates between bicuspid and tricuspid aortic valve repair. For Marfan syndrome, valve-sparing root replacement is advantageous compared to Bentall operation regarding late survival, thromboembolic and hemorrhagic events, and endocarditis. Similar findings have been reported in acute aortic dissection. Both remodeling and reimplantation procedures provide similar favorable outcomes in these settings. Recent advances in AVP are summarized by quantitative assessment of cusp configuration (effective height and geometric height), graft size decision, use of template to cut the graft, and videoscopic assessment of post-repair cusp configuration. Due to these advances, AVP shows superior results to replacement surgery. Further concrete evidence with larger case volumes and longer observation periods are necessary to popularize AVP.

Bicuspid aortic valve repair: the 180°-Reimplantation technique

Bicuspid aortic valves (BAVs) represent a wide spectrum of aortic valve phenotypes. We have therefore previously proposed a new repair-oriented surgical classification for BAVs in order to facilitate our understanding of any given phenotype and to guide surgical repair. BAVs can range from symmetric to very asymmetric, and classification is determined by commissural orientation. This can therefore range from 180° to 120° respectively, and as such has further implications for the presence or absence of a raphe; the height of the non-functional commissure (raphe); the length of the line of cusp fusion; and the architecture of the aortic valve sinuses. Over the last three decades, we have attempted different repair strategies for BAVs, with its respective learning curves and have achieved the best long-term repair results with our signature approach: the 180°-Reimplantation technique (El Khoury technique). Although very asymmetric and tricuspid aortic valve-like phenotypes are sometimes best repaired through tricuspidization, we have found that the majority of BAVs are amenable to our 180°-Reimplantation technique. This technique creates a symmetric valve, through a selective annuloplasty, and stabilization of the entire functional aortic annulus (FAA) with reimplantation of the commissure at 180° at the level of the virtual basal ring (VBR) and sinotubular junction (STJ). Depending on the valve phenotype, additional cusp modifications are often required to address one or two prolapsing cusps and/or a fibrous raphe. With this, we have previously reported a 12-year survival rate of 94%, which is alike the general population, and also an overall freedom from aortic valve reoperation of 91%.

Valve-sparing aortic root replacement: a primer for cardiologists

PURPOSE OF REVIEW

The purpose of this article is to review the contemporary evidence supporting valve-sparing aortic root replacement as the best option for patients with aortic root aneurysms and preservable aortic valves as well as to review the technical variations and modern adjuncts of these operations that impact both short and long-term durability.

RECENT FINDINGS

In patients with an aortic root aneurysm, with or without aortic valve regurgitation, valve-sparing aortic root replacement provide excellent clinical outcomes and stable valve function over several decades. Successful execution of this operation depends on careful patient selection and a thorough understanding of the anatomical and physiological relationships between the various components of the aortic root. Echocardiography remains the mainstay of imaging to determine the feasibility of valve-sparing root replacement.

SUMMARY

Valve-sparing aortic root replacement is an excellent alternative to composite valve graft replacement in nonelderly patients with aortic root aneurysms. Dedicated aortic root surgeons perform several technical variations of valve-sparing procedures aimed at matching the specific aortic root disorder with the optimal operation.

Successful Repair of a Forme Fruste Bicuspid Aortic Valve by the Raphe Suspension Technique

A 52-year-old man underwent surgery due to shortness of breath caused by severe aortic regurgitation with right coronary cusp prolapse. Operative findings revealed three symmetrical cusps with small raphe between the right- and non-coronary cusps situated lower than the others, indicating a forme fruste bicuspid aortic valve (BAV). The BAV was successfully repaired by tricuspidization, including raphe suspension, right coronary cusp plication, and double annuloplasty. The postoperative course was uneventful, and echocardiography at 3 months showed mild aortic regurgitation with adequate left ventricular reverse remodeling. Here, we present the technical details of the raphe suspension procedure for forme fruste BAV.