Patient prosthesis mismatch (PPM) is defined as an effective valve area of a surgically implanted prosthetic valve that is too small in relation to the patient’s body size and normal valve area.

Hemodynamically, the occurrence of PPM results in valvular pressure gradients that are higher than expected through a normally functioning prosthetic valve. Following surgical aortic valve replacement (SAVR), PPM is associated with increased short-term and long-term mortality which may be due to an increased risk of structural valve deterioration and heart failure ^(1-4). 

With the emergence of transcatheter aortic valve replacement (TAVR), valve-in-valve (ViV) TAVR is increasingly being utilized in patients with failing bioprosthetic valves ^(5,6). However, ViV TAVR carries a higher risk of PPM ⁽⁷⁾. In light of these trends in ViV TAVR and concerns for PPM, there has been an increased attention to methods for mitigating the occurrence of PPM at the time of SAVR. Aortic root enlargement (ARE) is a surgical procedure that can be performed at the time of SAVR that allows for implantation of larger prosthetic valves and thereby reduces the risk of PPM and potentially future PPM risk if ViV TAVR is indicated.

Historically, ARE has been underutilized due to concerns regarding the technical challenges of the procedure and the potential for increased short-term complications and mortality ^(8-10). However, numerous studies have demonstrated that ARE is generally a safe and effective procedure, although it may carry an elevated risk in patients over the age of 65 years ⁽¹¹⁾. Given the paucity of large-scale data on outcomes on SAVR + ARE, the current study compared in-hospital outcomes and complications of patients undergoing combined SAVR + ARE with those undergoing SAVR alone using a large representative hospital claims dataset.

In light of these gaps, we sought to describe contemporary utilization patterns and in-hospital outcomes of SAVR with concomitant ARE using a large, nationally representative, all-payer inpatient database. By including both academic and community hospitals across the United States, this analysis complements prior registry-based and single-center studies and provides insight into real-world practice patterns, perioperative risk, and resource use associated with SAVR + ARE.

Data Source

This was a retrospective cohort study of hospitalizations with a diagnosis of aortic stenosis undergoing SAVR or SAVR + ARE across the United States from 2016-2021. Hospital indexes were selected from the NIS database, which is the largest all-payer database of hospital inpatient stays in the United States Agency for Healthcare Research and Quality. Raw data from NIS represents a 20% stratified sample of hospitals in the United States and contains hospitalization and healthcare utilization information including procedures performed, length of stay (LOS), and hospitalization charges.

Discharge weights are provided for each patient discharge record, which were used to obtain national estimates. Discharge weights are calculated for NIS data by first stratifying the NIS hospitals on the same variables used for creating the sample. A weight is then calculated for each stratum by dividing the number of universe discharges in that stratum (obtained from American Hospital Association data) by the number of NIS discharges in the stratum. Weighted estimates are calculated by uniformly applying stratum weights to the discharges according to the stratum from which the discharge was drawn. Weights are assigned to each discharge and are stored in each record in the data element, DISCWT. When the discharge weights are applied to the unweighted NIS data, the result is an estimate of the number of discharges for all inpatient discharges from community hospitals in the United States. All ICD-10-CM and ICD-10-PCS codes used in this analysis can be found in the Supplementary Materials document. Of note, since there is no one primary ICD-10-PCS code for ARE, we performed a multi-hospital survey across three institutions (two tertiary centers and one community cardiac program) to determine the most commonly used procedural codes. Trained clinical abstractors reviewed operative reports for cases suspected of involving aortic root enlargement.

Across all confirmed cases, the ICD-10-PCS code 02UXO8Z was used consistently and exclusively to capture ARE, without concurrent ascending aortic grafting. To further improve specificity, we excluded cases with diagnostic codes for aortic aneurysm, dissection, and endocarditis. Additionally, we cross-validated these codes against other aortic surgical codes to minimize overlap. These codes were compared to other putative codes (02UF07Z, 02UF08Z, 02UF0JZ, 02UF0KZ and 02UXO7Z, O2UXO8Z, O2UXOJZ, and O2UXOKZ) to evaluate the possibility of missed cases using codes derived from our survey. Institutional Review Board approval is not required given NIS utilized de-identified data.

A key challenge in this analysis was the absence of a dedicated ICD-10 procedure code for aortic root enlargement (ARE). To address this, we conducted a structured multi-hospital chart review involving three institutions—two large tertiary cardiac surgery centers (Minneapolis Heart Institute and Dartmouth-Hitchcock Medical Center) and one community-based cardiac program. At each site, trained clinical abstractors and a local cardiac surgeon manually reviewed operative notes for patients who underwent SAVR+ARE was suspected based on preoperative indications or documentation. Reviewers identified the ICD-10-PCS codes assigned to these cases, and findings were cross-validated with surgical documentation to determine coding consistency. Manual chart review confirmed that this code corresponded to true root enlargement procedures, enhancing the reliability of case identification. A formal sensitivity analysis was not feasible due to limitations inherent in administrative data.

It is important to note that CPT codes are not available in the NIS dataset; therefore, all procedures were identified using ICD-10-PCS codes. As a result, we were unable to use CPT data to further validate ARE coding or to confirm the absence of additional concomitant cardiovascular procedures beyond those captured by ICD-10-PCS.

 Study Population

Individuals were identified using the International Classification of Diseases, 10th Revision, Clinical Modification codes (ICD-10-CM) as well as International Classification of Diseases, Tenth Revision, Procedure Coding System (ICD-10-PCS) codes (Supplementary Material 1). Using NIS, a cohort of adult admissions (18 years and older) with aortic stenosis in the primary diagnosis field was identified. Admissions were stratified into those receiving SAVR+ARE or SAVR. Only patients undergoing isolated SAVR or SAVR + ARE were included. Concomitant cardiac procedures (e.g., CABG, valve repair/replacement) during the same admission were not performed in this cohort. We excluded patients with the following conditions: infective endocarditis, thoracic aortic aneurysm, aortic dissection, and aortic regurgitation. These exclusions were implemented to create a more clinically homogeneous cohort with a standardized surgical indication—namely, aortic stenosis. Including patients with endocarditis or aortic regurgitation could introduce significant heterogeneity due to differing operative risk profiles, surgical approaches (e.g., valve repair vs. replacement), and procedural urgency, which may confound perioperative outcomes. Our goal was to isolate the effects of aortic root enlargement in a population undergoing elective SAVR for calcific or degenerative aortic stenosis, the most common indication for ARE.

 Study outcomes

Outcomes included in-hospital mortality, acute kidney injury, postoperative stroke, postoperative respiratory complications, cardiogenic shock, blood transfusion, mechanical ventilation, and

pacemaker placement (Supplementary Material 1) among patients undergoing SAVR+ARE compared to SAVR alone. Moreover, we analyzed contemporary outcomes of ARE used in mechanical versus tissue valves.

Statistical Analysis

Analysis was conducted using Stata BE version 18 (StataCorp, College Station, TX) on unweighted observations. To reduce confounding and selection bias, we performed propensity score matching using a multivariable logistic regression model that included demographics (age, sex, race), clinical comorbidities (e.g., diabetes, hypertension, obesity, hyperlipidemia, heart failure, atrial fibrillation, COPD, liver disease), and known risk factors for patient-prosthesis mismatch (PPM), such as female sex, older age, and elevated BMI. Hospital-level factors (teaching status, region) and primary payer were also included.

Matching was conducted using a 1:n nearest-neighbor variable ratio with a caliper of 0.1 standard deviations. Balance was assessed using standardized mean differences (SMD), with SMD <0.1 indicating acceptable match quality. Residual imbalances were noted and considered in interpretation.

Clustering of patients within hospitals was not explicitly modeled. Since the NIS samples discharges rather than hospitals, this may lead to underestimated standard errors. Although hospital characteristics were included in the model, future analyses may benefit from hierarchical or mixed-effects modeling.

Multivariable linear regression was used for continuous outcomes and logistic regression for binary outcomes. A p-value <0.05 was considered statistically significant.

Patient characteristics

A total of 70,071 SAVRs were performed between January 2016 and December 2021. Of those patients, 68,692 underwent SAVR, representing 98.4% of the cohort, whereas 1,109 patients underwent SAVR + ARE, representing 1.6% of the cohort. All patients included in the matched cohort underwent isolated SAVR or SAVR + ARE during the index hospitalization. No concomitant cardiac procedures (e.g., CABG, mitral or tricuspid valve surgery) were performed during the same surgical episode. The mean age in the SAVR + ARE group was 64.38 years (± 3.52) vs. 64.31 years (± 3.52) (p=0.88) among patients undergoing SAVR alone. The SAVR + ARE group contained 42.3% males vs. 54% males in the SAVR group (p<0.0001). White individuals made up the majority of the patient (~80%, p<0.0001). Comorbidities were balanced between groups with greater than 30% of individuals having a Charlson comorbidity index >3 in both groups (p=0.014). Covariate balance was confirmed after matching, with all absolute standardized mean differences (aSMDs) < 0.1, indicating appropriate match quality (Supplementary Table 2).

After propensity score matching, patient demographics between the SAVR and SAVR + ARE groups were generally similar. Compared to the SAVR + ARE group, patients undergoing SAVR alone had a higher proportion of male patients (54.0% vs. 50.3%, p < 0.001), more frequent bicuspid aortic valve (7.3% vs. 3.8%, p < 0.001), and a higher rate of alcohol use history (3.3% vs. 1.9%, p = 0.030). In contrast, obesity (35.0% vs. 25.8%, p < 0.001), hyperlipidemia (63.1% vs. 57.5%, p = 0.002), and diabetes mellitus (12.5% vs. 10.3%, p = 0.050) were more common in the SAVR + ARE group. Atrial fibrillation (41.4% vs. 46.8%, p = 0.003) and congestive heart failure (37.7% vs. 41.3%, p = 0.049) were also less prevalent in SAVR alone. (Table  1).

In-Hospital Outcomes

After propensity score matching, 1,099 patients (3.5%) undergoing SAVR died compared to 39 patients (5.3%) undergoing SAVR + ARE. However, this difference was not statistically significant (adjusted odds ratio [aOR]: 1.48, CI: [0.72 - 1.99], p = 0.067). In the unadjusted matched cohort, in-hospital mortality was 5.3% in the SAVR + ARE group vs. 3.5% in the SAVR-only group (OR 1.53; 95% CI: [1.10–2.12], p = 0.011). Postoperative respiratory failure occurred more frequently in the SAVR + ARE group (15.2%) compared to the SAVR group (12.7%) (aOR 1.73; CI: [1.12 - 2.44], p = 0.038). No statistically significant differences were observed between the two groups for other outcomes (Table 2). The incidence of bleeding was comparable (6.0%, 1,885 patients in the SAVR group vs. 4.0%, 30 patients in the SAVR + ARE group; aOR 1.32, p=0.429). Similarly, rates of pacemaker insertion (6.0%, 1,885 patients vs. 4.0%, 30 patients; aOR 0.769, p=0.235), cardiogenic shock (12.3%, 3,863 patients vs. 11.9%, 88 patients; aOR 1.05, p=0.690), and post-procedural infection (1.7%, 534 patients vs. 2.0%, 15 patients; aOR 1.22, p=0.833) did not differ significantly between the SAVR and SAVR + ARE groups (Table 2).

Health Utilization

The mean total hospitalization charge was numerically higher in the SAVR vs. SAVR +ARE ($281,598 vs.

$298,935 p=0.13) but these differences were not statistically significant in the matched sample. Length of stay (LOS) was longer in the SAVR + ARE group (10.48 vs 9.67 days, p = 0.42). There was no difference in discharge disposition between both groups with the majority of patients discharged home (self-care).

In-Hospital Outcomes According to Valve Type

We performed a subgroup-analysis in patients undergoing SAVR + ARE stratified by valve type. After propensity score matching, 8% (n=58) underwent SAVR + ARE with a mechanical valve vs. 92% (n=684) of patients received a bioprosthetic valve. There was no difference in in-hospital mortality or acute bleeding comparing mechanical vs tissue valves (aOR 1.34, p=0.35; aOR 1.21, p=0.72). There was an increased risk of pacemaker insertion in mechanical valves vs tissue valves (aOR 1.12, p<0.04).

Yearly Trends

Over the 6-year study period, we observed a significant increase in the overall use of SAVR + ARE, with the number of ARE procedures rising dramatically from 125 in 2016 to 1,275 in 2021—an increase of over 900% (p<0.001). Conversely, we did observe a gradual decrease in the number of SAVR only procedures, however the 29% drop between 2016 to 2021 was not found to be statistically significant (p=0.45) (Figure 2).

Distribution of Procedural Codes for Aortic Root Enlargement

Among patients identified as undergoing SAVR + ARE within the NIS database, the ICD-10-PCS code 02UXO8Z (zooplastic tissue) was used in over 85% of cases. This was followed by similar usage of 02UXO7Z (autologous tissue) and 02UXOJZ (synthetic substitute), each accounting for approximately 4–6% of procedures. The code 02OXOKZ, representing nonautologous tissue, was used in less than 1% of cases. In our multi-hospital survey, across all institutions, the code 02UX08Z was used in 100% of confirmed ARE cases. This code and the other presumed ARE ICD-10 codes were not used in any other cases of SAVR without ARE.

g

Table 1. Baseline Characteristics: Comparison of SAVR Alone vs. SAVR + ARE, Stratified by Propensity- Matched and Unmatched Groups *CHF= chronic congestive heart failure (both systolic and diastolic)

Table 2. Outcomes of propensity matched groups between those with SAVR only vs those who received SAVR with ARE

 *PPMI: permanent pacemaker insertion.

Figure 1. Total amount of surgical aortic valve replacements (SAVR) with aortic root enlargement (ARE) per year

Figure 2. Total number of surgical aortic valve replacements (SAVR) per year

In this large, contemporary and nationally representative study, we evaluated the utilization and in-hospital outcomes of aortic root enlargement among adults undergoing surgical aortic valve replacement. Overall, patients treated with SAVR + ARE did not experience a significantly higher adjusted risk of in-hospital mortality compared with those undergoing isolated SAVR. Major cardiovascular complications—including shock, stroke, bleeding, and pacemaker implantation—were also comparable between groups. By leveraging a broad population from an all-payer dataset that includes both academic and community hospitals, this analysis provides complementary and contemporary, real-world evidence on the short-term safety profile of ARE in routine clinical practice.

Large-scale studies evaluating outcomes after SAVR with concomitant ARE remain limited. In the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database analysis of 5,412 older patients, Mehaffey et al. reported higher 30-day mortality and early postoperative complications with ARE, although long-term outcomes and 3-year survival favored the ARE cohort ⁽¹¹⁾. In contrast, our study included a broader adult population (≥18 years) from a more contemporary cohort (2016-2021 compared to 2008-2016). We observed a numerically higher in-hospital mortality in the SAVR + ARE group (5.3% vs. 3.5%) among patients from the NIS registry which was strikingly similar to the 30-day adjust risk of complication and death in the study by Mehaffey et al. (5.4% vs 3.4%, P < .0001), however this difference did not remain statistically significant in our study population after adjustment (aOR 1.48; p = 0.067). This pattern is directionally consistent with early risk signals in the STS analysis and may reflect residual confounding or unmeasured surgical complexity. Lastly, in contrast to the findings of Mehaffey et al., we did observe a significant increase in the overall use of SAVR + ARE over our more contemporary study period. These findings should be interpreted cautiously and underscore the need for further study in well-phenotyped patient cohorts.

Additional observational data support the general safety of ARE when performed in appropriately selected patients. In a single-center study of 1,854 patients, higher in-hospital mortality was observed only among those undergoing SAVR + ARE with concomitant procedures; among isolated SAVR cases, ARE did not confer increased risk after adjustment ^(12,13). Similarly, a meta-analysis of 2,570 patients reported no difference in early (30-day) mortality or major in-hospital complications between SAVR + ARE and isolated SAVR ⁽¹⁴⁾. Tam et al. likewise found no increase in short-term mortality or complications in a multicenter propensity-matched cohort of 809 patients ⁽¹⁵⁾. Our findings align with these prior studies, reinforcing that ARE, when used to optimize valve hemodynamics or prosthesis size, does not appear to substantially elevate early postoperative risk.

Although most major complications were similar between groups, patients undergoing SAVR + ARE had a numerically higher rate of postoperative respiratory failure (~2.5%), which may partly explain the slightly higher mean length of stay and hospital charges observed. However, none of these differences reached statistical significance. These findings suggest that while ARE may modestly increase perioperative complexity, it does not substantially impact short-term resource utilization at a national level.

Prior studies and meta-analyses have demonstrated that severe prosthesis–patient mismatch is associated with reduced short- and long-term survival after SAVR (9,10). ARE offers a mechanism to reduce PPM risk by enabling implantation of a larger prosthesis, yet national utilization remains low. In our analysis, SAVR + ARE accounted for <2% of all SAVR procedures, although we observed a modest upward trend in ARE use over the study period. This aligns with recent single-center reports demonstrating increased adoption of ARE from 2016 to 2022 ⁽⁸⁾. We did not observe an increased mortality risk associated with ARE, a finding consistent with the elective-surgery subgroup analysis by Son et al., who reported similar early outcomes and postoperative gradients between patients undergoing SAVR + ARE and those undergoing SAVR alone.

We found that most ARE procedures were performed in the southern United States (~38%), although operative region was not associated with differences in mortality or complications ^(16,17). Similarly, procedure volume was not associated with adverse outcomes. The majority of SAVR + ARE cases occurred at academic hospitals (87%), yet mortality rates did not differ between academic and non-academic centers, suggesting that ARE can be performed safely across diverse surgical environments. Hospital charges were also comparable between groups, and outcomes did not differ across quartiles of median household income based on patient zip code.

Together, these findings contribute contemporary, nationally representative evidence demonstrating that ARE is used infrequently but appears safe in the short term when added to SAVR. While a modest signal toward higher early mortality warrants cautious interpretation, our results broadly align with prior single-center, multicenter, and registry-based studies showing no significant increase in early postoperative complications. Future studies with detailed anatomic, procedural, and longitudinal data are needed to clarify patient selection, quantify the hemodynamic benefit of ARE, and determine its long-term impact on clinical outcomes and prosthesis durability.

Limitations

There are several important limitations to this analysis. The NIS is an administrative, discharge-level database that relies on ICD-10 coding and does not contain detailed clinical, anatomic, or longitudinal follow-up data. As a result, we were unable to assess baseline left ventricular function, aortic annular or root dimensions, surgical technique, or post-operative hemodynamics, nor could we determine the degree of annular enlargement achieved or the effectiveness of individual ARE techniques. Similarly, we could not evaluate longer-term outcomes such as structural valve deterioration, late prosthesis–patient mismatch, rehospitalization, or survival beyond the index hospitalization.

With regard to procedure identification, there is no dedicated ICD-10-PCS code for aortic root enlargement, and our case definition therefore relied on codes that are most commonly used in practice. Although we performed a structured multi-hospital chart review across two tertiary cardiac surgery centers and one community-based program to validate these codes, misclassification and under- or over-ascertainment of ARE cannot be excluded. However, similar to other investigators (Zafar et al.: https://www.sciencedirect.com/science/article/pii/S0022522321014847) using administrative data to identify surgical procedures without dedicated ICD10 codes, we conducted a multi-hospital coding survey to improve evaluate the specificity of ARE identification and to characterize the distribution of ICD-10-PCS codes used for these procedures. Our survey of two academic and one community hospital demonstrated uniformity and consistency in the use of the codes utilized in our NIS analysis thereby supporting our choice of ICD10 codes.

Despite these limitations, our analysis provides complementary, nationally representative data on the real-world utilization of SAVR + ARE, associated in-hospital outcomes, and resource use across a broad spectrum of U.S. hospitals. These findings should therefore be interpreted as hypothesis-generating and as a contemporary description of practice patterns and in-hospital safety rather than as a definitive assessment of the long-term risk–benefit profile of ARE.

Among a nationally representative cohort of patients, ARE at the time of SAVR has increased over the last decade. Reassuringly, the addition of ARE to SAVR is not associated with an increased risk of in-hospital mortality or major complication compared to SAVR alone. Further research is needed to investigate the short- and long-term risks associated with ARE among patients undergoing SAVR.

Supplementary Material

Used ICD-10 CM and PCS Codes

Disclaimers

The authors have no disclaimers to report.

Conflicts of interest

The authors have no conflicts of interest to report.

Sources of support

The authors have no sources of support/funding to report.

Acknowledgements

The authors have no acknowledgements to address.

Data Availability

The authors declare that data supporting the findings of this study are available within the article.

1.    MPB. de O. Sá, M.M.B. de Carvalho, D.C. Sobral Filho, et al. Surgical aortic valve replacement and patient–prosthesis mismatch: a meta-analysis of 108 182 patients Eur J Cardiothorac Surg, 56 (2019), pp. 44-54, 10.1093/ejcts/ezy466
2.    S.J. Head, M.M. Mokhles, R.L. Osnabrugge, et al. The impact of prosthesis-patient mismatch on long-term survival after aortic valve replacement: A systematic review and meta-analysis of 34 observational studies comprising 27,186 patients with 133,141 patient-years Eur Heart J, 33 (12) (2012), pp. 1518-1529
3.    Dismorr M, Glaser N, Franco‐Cereceda A, Sartipy U. Effect of prosthesis‐patient mismatch on long‐term clinical outcomes after bioprosthetic aortic valve replacement. J Am Coll Cardiol. 2023;81:964–975.
4.    E.H. Blackstone, D.M. Cosgrove, W.R. Jamieson, et al. Prosthesis size and long-term survival after aortic valve replacement J Thorac Cardiovasc Surg, 126 (3) (2003), pp. 783-796
5.    Dvir D, Webb J, Brecker S, Bleiziffer S, Hildick-Smith D, Colombo A, Descoutures F, Hengstenberg C, Moat NE, Bekeredjian R, Napodano M, Testa L, Lefevre T, Guetta V, Nissen H, Hernández JM, Roy D, Teles RC, Segev A, Dumonteil N, Fiorina C, Gotzmann M, Tchetche D, Abdel-Wahab M, De Marco F, Baumbach A, Laborde JC, Kornowski R.
6.    Transcatheter aortic valve replacement for degenerative bioprosthetic surgical valves: results from the global valve-in-valve registry. Circulation.
7.    Kapadia SR, Kodali SK, Pichard AD, et al. Valve-in-Valve TAVR for Degenerated Bioprosthetic Aortic Valves: Insights from the STS/ACC TVT Registry. J Am Coll Cardiol. 2021;77(12):1478-1490. doi:10.1016/j.jacc.2020.11.055
8.    Sá M.P.B.O., Van den Eynde J., Simonato M., et al. "Valve-in-valve transcatheter aortic valve replacement versus redo surgical aortic valve replacement: an updated meta-analysis". J Am Coll Cardiol Intv . 2021;14:2: 211-220.

9.    Son AY, Baldridge AS, Churyla A, et al. Trends and Outcomes of Aortic Root Enlargement During Bioprosthetic Aortic Valve Replacement. Ann Thorac Surg Short Rep. 2024;3(4):e123-130. doi:10.1016/j.atsr.2024.03.001
10.    Takagi H, Yamamoto H, Iwata K, Goto SN, Umemoto T. A meta-analysis of effects of prosthesis-patient mismatch after aortic valve replacement on late mortality. Int J Cardiol 2012;159:150–4.
11.    Dayan V, Vignolo G, Soca G, Paganini JJ, Brusisch D, Pibarot P. Predictors and outcomes of prosthesis-patient mismatch after aortic valve replacement. JACC Cardiovasc Imaging 2016;9:924–33.
12.    Mehaffey J.H., Hawkins R.B., Wegermann Z.K., Grau-Sepulveda M.V., Fallon J.M., Brennan J.M., Thourani V.H., Badhwar V., Ailawadi G. Aortic Annular Enlargement in the Elderly: Short and Long-Term Outcomes in the United States. Ann. Thorac. Surg. 2021;112:1160– 1166. doi: 10.1016/j.athoracsur.2020.12.023.
13.    Dhareshwar J., Sundt T.M., Dearani J.A., Schaff H.V., Cook D.J., Orszulak T.A. Aortic Root Enlargement: What Are the Operative Risks? J. Thorac. Cardiovasc. Surg. 2007;134:916– 924. doi: 10.1016/j.jtcvs.2007.01.097.
14.    Rocha RV, Manlhiot C, Feindel CM, et al. Surgical Enlargement of the Aortic Root Does Not Increase the Operative Risk of Aortic Valve Replacement. Circulation. 2018;137(15):1585- 1594. doi:https://doi.org/10.1161/circulationaha.117.030525
15.    Yu W, Tam DY, Rocha RV, Makhdoum A, Ouzounian M, Fremes SE. Aortic Root Enlargement Is Safe and Reduces the Incidence of Patient-Prosthesis Mismatch: A Meta- analysis of Early and Late Outcomes. Can J Cardiol. 2019;35(6):782-790. doi:10.1016/j.cjca.2019.02.004
16.    Tam DY, Dharma C, Rocha RV, et al. Early and late outcomes following aortic root enlargement: A multicenter propensity score-matched cohort analysis. J Thorac Cardiovasc Surg. 2020;160(4):908-919.e15. doi:10.1016/j.jtcvs.2019.09.062
17.    Correia PM, Coutinho GF, Branco C, Antunes MJ. Long-term follow-up of patients undergoing aortic root enlargement for insertion of a larger prosthesis. Eur J Cardiothorac Surg 2016;50:82–8.
18.    Rao V, Linick JA, Reardon MJ, Vriesendorp MD, Ruel M, Patel HJ, Liu F, Klautz RJM. Early and late effects of aortic root enlargement: Results from the Pericardial Surgical Aortic Valve Replacement Pivotal Trial: A multicenter, prospective clinical trial. JTCVS Open. 2022 Dec 6;13:54-74. doi: 10.1016/j.xjon.2022.11.013. PMID: 37063123; PMCID: PMC100912