Full-root aortic valve replacement with stentless xenograft achieves superior regression of left ventricular hypertrophy compared to pericardial stented aortic valves

Midterm outcomes of subcoronary stentless porcine valve versus stented aortic valve replacement

INTRODUCTION

Stentless porcine xenografts are versatile bioprosthetic valves with the advantage of improved hemodynamics that mimic the function of the native aortic valve. However, these bioprostheses are challenging to implant in the subcoronary position.

METHODS

All consecutive patients who underwent a bioprosthetic aortic valve replacement (AVR) were included from our institutional database. Cox regression analysis was preformed to determine significant predictors for mid term mortality as well as all cause, cardiac, and heart failure readmission.

RESULTS

Patients in the subcoronary stentless group were older and more likely to be female and were likely to have a higher Society of Thoracic Surgery risk of mortality. Survival was superior in the stented AVR cohort at 30-days (96.4% vs 90.5%; P < .001), 1-year (90.5% vs 71.6%; P < .001), and 5-year (74.5% vs 56.9%; P < .001) follow up. Acute kidney injury (16.22% vs 5.22%; P < .001) and blood product transfusion (70.27% vs 44.0%; P < .001) were higher in the stentless group. Multivariable analysis revealed subcoronary stentless implantation as a significant independent risk factor for mortality (hazards ratio: 1.92 [1.35,2.72]; P < .001).

CONCLUSION

Stentless porcine xenograft implantation with the Freestyle bioprosthetic in the subcoronary position can be successfully performed in select patients, but its use is associated with increased perioperative morbidity and mortality affecting midterm outcomes. Individual patient selection and surgeon experience are important to ensure favorable outcomes.

Surgery for Young Adults With Aortic Valve Disease not Amenable to Repair

Aortic valve replacement is the gold standard for the management of patients with severe aortic stenosis or mixed pathology that is not amenable to repair according to currently available guidelines. Such a simplified approach may be suitable for many patients, but it is far from ideal for young adults considering emerging evidence demonstrating that conventional valve replacement in this cohort of patients is associated with inferior long-term survival when compared to the general population. Moreover; the utilisation of mechanical and bioprosthetic valves can significantly impact on quality and is linked to increased rates of morbidities. Other available options such as stentless valve, homografts, valve reconstruction and Ross operation can be an appealing alternative to conventional valve replacement. Young patients should be fully informed about all the options available - shared decision making is now part of modern informed consent. This can be achieved when referring physicians have a better understanding of the short and long term outcomes associated with every intervention, in terms of survival and quality of life. This review presents up to date evidence for available surgical options for young adults with aortic stenosis and mixed disease not amenable to repair.

Biological aortic valve replacement: advantages and optimal indications of stentless compared to stented valve substitutes. A review

Controversy still surrounds the optimal biological valve substitute for aortic valve replacement. In light of the current literature, we review advantages and optimal indications of stentless compared to stented aortic bio-prostheses. Recent meta-analyses, prospective randomized controlled trials and retrospective studies comparing the most frequently used stentless and stented aortic bio-prostheses were analyzed. In the present review, the types and implantation techniques of the bio-prosthesis that are seldom taken into account by most studies and reviews were integrated in the interpretation of the relevant reports. For stentless aortic root bio-prostheses, full-root vs. sub-coronary implantation offered better early transvalvular gradients, effective orifice area and left ventricular mass regression as well as late freedom from structural valve deterioration in retrospective studies. Early mortality and morbidity did not differ between the stentless and stented aortic bio-prostheses. Early transvalvular gradients, effective orifice area and regression of left ventricular hypertrophy were significantly better for stentless, especially as full-root, compared to stented bio-prostheses. The long-term valve-related survival for stentless aortic root and Toronto SPV bio-prosthesis was as good as that for stented pericardial aortic bio-prostheses. For full-root configuration this survival advantage was statistically significant. There seems to be not one but different ideal biological valve substitutes for different subgroups of patients. In patients with small aortic root or exposed to prosthesis-patient mismatch full-root implantation of stentless bio-prostheses may better meet functional needs of individual patients. Longer follow-ups on newer generation of stented bio-prostheses are needed for comparison of their hemodynamic performance with stentless counterparts especially in full-root configuration.

Full-root Aortic Valve Replacement by Stentless Aortic Xenografts in Patients with Small Aortic Roots

In patients with small aortic roots who need an aortic valve replacement with biological valve substitutes, the implantation of the stented pericardial valve might not meet the functional needs. The implantation of a too-small stented pericardial valve, leading to an effective orifice area indexed to a body surface area less than 0.85 cm²/m², is regarded as prosthesis-patient mismatch (PPM). A PPM negatively affects the regression of left ventricular hypertrophy and thus the normalization of left ventricular function and the alleviation of symptoms. Persistent left ventricular hypertrophy is associated with an increased risk of arrhythmias and sudden cardiac death. In the case of predictable PPM, there are three options: 1) accept the PPM resulting from the implantation of a stented pericardial valve when comorbidities of the patient forbid the more technically demanding operative technique of implanting a larger prosthesis, 2) enlarge the aortic root to accommodate a larger stented valve substitute, or 3) implant a stentless biological valve or a homograft. Compared to classical aortic valve replacement with stented pericardial valves, the full-root implantation of stentless aortic xenografts offers the possibility of implanting a 3-4 mm larger valve in a given patient, thus allowing significant reduction in transvalvular gradients. However, a number of cardiac surgeons are reluctant to transform a classical aortic valve replacement with stented pericardial valves into the more technically challenging full-root implantation of stentless aortic xenografts. Given the potential hemodynamic advantages of stentless aortic xenografts, we have adopted full-root implantation to avoid PPM in patients with small aortic roots necessitating an aortic valve replacement. Here, we describe in detail a technique for the full-root implantation of stentless aortic xenografts, with emphasis on the management of the proximal suture line and coronary anastomoses. Limitations of this technique and alternative options are discussed.