Aortic root enlargement to mitigate patient-prosthesis mismatch: do early adverse events justify reluctance?†

Aortic root enlargement and replacement of the ascending aorta in type 0 aortic valve stenosis

INTRODUCTION

This case report aims to describe an aortic root enlargement in combination with the replacement of the ascending aorta in a patient presenting with severe aortic valve stenosis.

CASE REPORT

A 68-year-old woman with severe aortic stenosis due to a type 0 bicuspid aortic valve and an aortic aneurysm underwent surgery for treatment. The annulus was preoperatively measured with 19 mm. Enlargement was performed by using a tissue patch to create a neo-noncoronary sinus and enlarge the root.

DISCUSSION

Patients with a small aortic root face an increased risk of patient prosthesis mismatch. Enlarging the aortic root can mitigate this, but it extends cross-clamp and overall operative times. This case shows the need for carefully planned surgical interventions to optimize outcomes in complex anatomies.

CONCLUSIONS

Each step of the performed surgery is well-established, however the combination and the creation of a neo-noncoronary sinus is not described so far.

Prosthesis-Patient Mismatch and Aortic Root Enlargement: Indications, Techniques and Outcomes

Prosthesis-patient mismatch (PPM) is defined as implanting a prosthetic that is insufficiently sized for the patient receiving it. PPM leads to high residual transvalvular gradients post-aortic valve replacement and consequently results in left ventricular dysfunction, morbidity and mortality in both the short and long term. Younger patients and patients with poor preoperative left ventricular function are more vulnerable to increased mortality secondary to PPM. There is debate over the measurement of valvular effective orifice area (EOA) and variation exists in how manufacturers report the EOA. The most reliable technique is using in vivo echocardiographic measurements to create tables of predicted EOAs for different valve sizes. PPM can be prevented surgically in patients at risk through aortic root enlargement (ARE). Established techniques include the posterior enlargement through Nicks and Manouguian procedures, and aortico-ventriculoplasty with the Konno-Rastan procedure, which allows for a greater enlargement but carries increased surgical risk. A contemporary development is the Yang procedure, which uses a Y-shaped incision created through the non- and left-coronary cusp commissure, undermining the nadirs of the non- and left-coronary cusps. Early results are promising and demonstrate an ability to safely increase the aortic root by up to two to three sizes. Aortic root enlargement thus remains a valuable and safe tool in addressing PPM, and should be considered during surgical planning.

Surgical versus transcatheter aortic valve replacement: Impact of patient-prosthesis mismatch on outcomes

BACKGROUND

The hemodynamics of most prosthetic valves are often inferior to that of the normal native valve, and a significant proportion of patients undergoing surgical (SAVR) or transcatheter aortic valve replacement (TAVR) have high residual transaortic pressure gradients due to prosthesis-patient mismatch (PPM). As the experience with TAVR has increased and long-term outcomes are reported, a close look at the PPM literature is required in light of new evidence.

METHODS

For this review, we searched the Embase, Medline, and Cochrane databases from 2000 to 2022. Articles reporting PPM as an outcome following aortic valve replacements were identified and reviewed.

RESULTS

The impact of PPM on clinical outcomes in aortic valve replacement has not been clear as multiple studies failed to report PPM incidence. However, the PPM outcomes after SAVR vary more widely than after TAVR, ranging from 8% to 80% in SAVR and from 24% to 35% in TAVR. Incidence of severe PPM following redo SAVR ranges from 2% to 9% and following valve-in-valve TAVR is from 14% to 33%, however, while PPM is higher in valve-in-valve TAVR, patients had better survival rates.

CONCLUSIONS

The gap between valve performance and clinical outcomes in SAVR and TAVR could be reduced by carefully selecting patients for either treatment option. Understanding predictors of PPM can add to the safety, effectiveness, and increased survival benefit of both SAVR and TAVR.

Lifetime management of aortic valve disease: Aligning surgical and transcatheter armamentarium to set the tone for the present and the future

Transcatheter aortic valve replacement (TAVR) has already received the green light for high-, intermediate- and low-risk profiles and is an alternative for all patients regardless of age. It is clear that there has been a push towards the use of TAVR in younger and younger patients (<65 years), which has never been formally tested in randomized controlled trials but seems inevitable as TAVR technology makes steady progress. Lifetime management as a concept will set the tone in the field of the structural heart. Some subjects in this scenario arise, including the importance of optimized prosthetic hemodynamics for lifetime care; surgical procedures in the aortic root; management of structural valve degeneration with valve-in-valve procedures (TAVR-in-surgical aortic valve replacement [SAVR] and TAVR-in-TAVR) and redo SAVR; commissural alignment and cusp overlap for TAVR; the rise in the number of surgical procedures for TAVR explantation; and the renewed interest in the Ross procedure. This article reviews all these issues which will become commonplace during heart team meetings and preoperative conversations with patients in the coming years.

Aortic root enlargement: When and how

Aortic valve replacement is the definitive management for severe aortic stenosis. Intraoperatively, an aortic root enlargement (ARE) may be used to facilitate the implementation of a suitably sized prosthetic valve. This is to prevent patient prosthesis mismatch (PPM), a condition that causes a left ventricular outflow obstruction. There are four main techniques that are used to perform ARE, namely, Nicks, Manouguian, Nunez (modified Manouguian), and Kanno-Rastan procedures. They each involve incisions through different anatomical structures and allow a variety of valve sizes to be implanted. Studies prove that ARE effectively reduces the incidence of PPM. In addition, they show that there is no definitive link between ARE and perioperative mortality or other complications. There is a scarcity of literature exploring the comparative outcomes of each surgical technique. Therefore, further research is warranted for these procedures to be compared adequately. This review aims to summarise the available literature surrounding ARE with respect to three main questions. (1) What are the indications for ARE, (2) what surgical techniques exist to facilitate ARE, and (3) are there significant differences in patient outcomes when these surgical techniques are employed?

Enlargement of the narrow aortic root: Fear of what?

Prosthesis-patient mismatch (PPM) associated with aortic valve replacement, especially of aortic stenosis, is a common problem. Severe PPM is known to increase perioperative morbidity and mortality and to negatively affect late survival. Surgical enlargement of the narrow aortic root enlargement (ARE) is now increasingly accepted as a method of facilitating implantation of a larger valve prosthesis, hence decreasing the risk of PPM. There are diagnostic methods and tables that help to predict the risk of this complication and assist in the planning of the surgery. Still, many surgeons are afraid or reluctant to perform ARE because of potential technical complications of a procedure perceived to increase the complexity of the surgery. However, these procedures have been proven safe and effective, and are at the reach of almost any cardiac surgeon, including less experienced ones. In addition, there are modifications to the techniques that make them even simpler and more reproducible.

Impact of Aortic Annulus Enlargement on the Outcomes of Aortic Valve Replacement: A Meta-analysis

We sought to evaluate the impact of surgical aortic annulus enlargement (ARE) on the perioperative outcomes of surgical aortic valve replacement. Databases were searched for articles published by October 2019 in order to carry out a systematic review followed by meta-analysis. Thirteen studies with 40,447 patients (aortic valve replacement [AVR] with aortic annulus enlargement [AAE]: 4686 patients; AVR without AAE: 35,761 patients) were included. The total rate of AAE was 11.6%, ranging from 4.1%-28.1%. The overall unadjusted odds ratio (OR) (95% confidence interval [CI]) for operative mortality showed a statistically significant difference between the groups, with higher risk in the "AVR with AAE" group (OR 1.388; 95% CI 1.049-1.836, P < 0.001), but not for isolated AVR+AAE (OR 1.341; 95% CI 0.920-1.956, P = 0.127) and also not in matched populations (OR 1.003; 95% CI 0.773-1.300, P = 0.984). The "AVR with AAE" group showed an overall lower risk of significant patient-prosthesis mismatch (PPM) (OR 0.567; 95% CI 0.376-0.854, P = 0.007) and a higher overall difference in means of indexed effective orifice area (iEOA) (random effect model: 0.058 cm²/m²; 95% CI 0.024-0.092, P < 0.001). The overall ORs for myocardial infarction, stroke, complete heart block/permanent pacemaker implantation and reoperation for bleeding showed no statistically significant difference between the groups. AAE is a useful adjunct to AVR, but the benefit of reduced PPM must be balanced against a possibly higher risk of perioperative mortality.

Impact of Prosthesis-Patient Mismatch on 1-Year Outcomes after Transcatheter Aortic Valve Implantation: Meta-analysis of 71,106 Patients

OBJECTIVES

This study sought to evaluate the impact of prosthesis-patient mismatch (PPM) on the risk of early-term mortality after transcatheter aortic valve implantation (TAVI).

METHODS

Databases (Medical Literature Analysis and Retrieval System Online [MEDLINE], Excerpta Medica dataBASE [EMBASE], Cochrane Controlled Trials Register [CENTRAL/CCTR], ClinicalTrials.gov, Scientific Electronic Library Online [SciELO], Latin American and Caribbean Literature on Health Sciences [LILACS], and Google Scholar) were searched for studies published until February 2019. PPM after TAVI was defined as moderate if the indexed effective orifice area (iEOA) was between 0.85 cm2/m2 and 0.65 cm2/m2 and as severe if iEOA ≤ 0.65 cm2/m2.

RESULTS

The search yielded 1,092 studies for inclusion. Of these, 18 articles were analyzed, and their data extracted. The total number of patients included who underwent TAVI was 71,106. The incidence of PPM after TAVI was 36.3% (25,846 with PPM and 45,260 without PPM). One-year mortality was not increased in patients with any PPM (odds ratio [OR] 1.021, 95% confidence interval [CI] 0.979-1.065, P=0.338) neither in those with moderate PPM (OR 0.980, 95% CI 0.933-1.029, P=0.423). Severe PPM was separately associated with high risk (OR 1.109, 95% CI 1.041-1.181, P=0.001).

CONCLUSION

The presence of severe PPM after TAVI increased early-term mortality. Although moderate PPM seemed harmless, the findings of this study cannot not rule out the possibility of it being detrimental, since there are other registries that did not address this issue yet.