Background: Aortic stenosis (AS) is the most common heart valve disease in Europe and North America. Age-related calcification of the valve is the commonest cause of acquired AS, especially in patients older than 70 years.Conventional surgical aortic valve replacement (SAVR) and the novel, minimally invasive transcatheter aortic valve implantation (TAVI), effectively preserve left ventricular (LV) function, relieve symptoms and improve survival in patients with severe symptomatic AS. However, patients with impaired LV function may carry significant operative risk, and long recovery time. In addition, such patients might have other comorbidities, and hence adding another challenge. Thus evaluation of ventricular function before and after AVR, as well as critical evaluation of TAVI patients should contribute to better clinical outcome. Methods: We studied LV function by conventional echocardiography before and after SAVR in the following groups; (I) 86 patients (aged 71±10 years) with severe AS and LV dysfunction; (II) 112 consecutive elderly AS patients (aged 77±2 years) and compared them with 72 younger patients (aged 60±1 years); (III)66 patients (age 70±2 years, 53 male) who underwent AVR for severe AS with concurrent LV dysfunction; (IV) 89 consecutive patients with symptomatic severeAS who underwent successful TAVI, 45 of whom received trans-apical TAVI (TA)(age 80.8±4.9 year, 26 male) and 44 trans-femoral TAVI (TF) (age 82.9±5.8 year,22 male).The conventional echocardiographic measurements were made according to the guidelines. Severe AS was identified by aortic valve mean pressure gradient >40mmHg or valve area <1.0 cm2. LV systolic dysfunction was identified as ejection fraction (EF) <50%. LV long-axis function was presented by mitral annular plane systolic excursion ( MAPSE ) at lateral wall and septal wall, which were measured from apical four-chamber view. Also from the same view, LV septal and lateral wall deformation using STE as well as global longitudinal systolic strain. The LV systolic twist as the net difference between apical rotation and basal rotation was measured from the parasternal apical and basal short-axis views in the TAVI patients. Results: Study I: In the low flow and high gradient group, operative (30-day) mortality was 10%, and peri-operative mortality was associated with lower mean LVEF, higher mitral E:A ratio, peak systolic pulmonary artery pressure (PSPAP), and higher serum creatinine (all p<0.001), NYHA class III–IV, concomitant coronary artery bypass graft (CABG), urgent surgery, and longer bypass-time (all p< 0.05). Mortality at 4 years was 17%. Univariate predictors of 4-year mortality were: lower EF (p<0.001), presence of restrictive LV filling (p<0.001), raised PSPAP (p<0.001) and CABG (p=0.037). However, only EF<40 % (p=0.03), the presence of restrictive LV filling (p=0.033) and raised PSPAP (p<0.01)independently predicted mortality in this group.Study II: Elderly patients had higher NYHA class, more frequent atrial fibrillation (AF), coronary artery disease (CAD), emergency operation and use of bioprosthetic valves. They also had shorter E-wave deceleration time (DT) and larger left atria (LA) (p<0.05 for all). 30-day mortality was 12% vs 4 % (Log Rank x2=3.02, p=0.08) and long term mortality was 18% vs 7% (Log Rank x2=4.38,p=0.04) in the two groups, respectively. Age was not related to mortality after adjustment for other variables. Among all variables, anemia (OR 4.20, CI:1.02–6.86, p=0.04), cardiopulmonary bypass (CPB) time (OR 1.02, CI 1.01–1.04,p<0.01), significant patient prosthesis mismatch (PPM) (OR 5.43, CI 1.04–18.40,p<0.05) were associated with 30-day mortality in elderly patients. Their long-term mortality was related to CBP time (OR 1.02, CI 1.00–1.05, p=0.04),PPM (OR 4.64, CI 1.33–16.11, p=0.02) and raised LA pressure: DT (OR 0.94, CI0.84–0.99, p=0.03) and pulmonary artery systolic pressure (PASP) (OR 1.12, CI1.03–1.19, p<0.001).STUDY III: Following SAVR peak aortic pressure gradient (AOPG) decreased and indexed valve area increased (64±3 to 19±1 mmHg and 0.30±0.01 to 0.89±0.03 cm2/m2, p<0.001 for both). LVEF increased (from 45±1 to 54±2%;p<0.001), LV end diastolic and end-systolic dimensions fell (LVEDD index: from 33±1 to 30±1 mm/m2; and LVESD index: from 27±1 to 20±1 mm/m2; (p<0.01 forboth). LV diastolic dysfunction improved as evidenced by the fall in E/A ratio (from 2.6±0.2 to 1.9±0.4) and prolongation of total filling time; (from 29.2±0.6 to31.4±0.5 s/min, p=0.01 for both). Among all echocardiographic variables, LV dimensions (LVEDD index, OR 0.70, CI 0.52–0.97, p<0.05; LVESD index, OR 0.57, CI 0.40–0.85, p=0.005) were the two independent predictors of post-operative LV functional recovery on multivariate analysis. A cut-off value ofpre-operative LVESD index<=27.5 mm/m2 was 85% sensitive and 72% specific inpredicting intermediate-term recovery of LV function after AVR (AUC, 0.72, p=0.002). STUDY IV: Before TAVI, there was no difference between the two patient groups in gender, age, body surface area (BSA) and baseline LV function. However, left ventricular mass index (LVMi), left atrial volume index (LAVi) and tricuspid regurgitation pressure drop (TRPdrop) were increased in the TA group (p<0.05).One week after TAVI, aortic pressure gradient (AOPG) markedly dropped in thetwo groups (both p<0.001), LVEDD index and LVESD index fell but EF andmyocardial strain remained unchanged. Overall cavity twist reduced (p<0.048).Significant LVESD index reduction was only seen in TF group (p=0.02) with a slight increase in LVEF (p=0.04). Lateral MAPSE increased only in the TF group(p=0.02). LV longitudinal systolic strain remained unchanged in TA patients while apical lateral strain increased in TF group. LV apical rotation fell in the two groups but basal rotation increased only in the TA patients (p=0.02). LAVi reduced in bothgroups and to a greater extent in TF TAVI (p=0.006), as did TRPdrop (p<0.001). Conclusion: SAVR and TAVI are two effective treatments for severe AS patients.The severity of pre-operative systolic and diastolic LV dysfunction is the major predictor of mortality following SAVR for low-flow and high gradient AS.Peri-operative AVR survival is encouraging in the elderly. Long term mortality in the elderly is related to PPM, LV diastolic dysfunction and secondary pulmonary hypertension. LV functional recovery was evident in most patients with LV dysfunction after SAVR. A lower prevalence of LV functional recovery in patients with large pre-operative LVESD index might signify the loss of contractile reserveand thus predict post-operative functional recovery. TAVI results in significant early improvement of segmental and overall ventricular function, particularly in patients receiving the trans-femoral approach. The delayed recovery of the trans-apical TAVI group, we studied, might reflect worse pre-procedural diastolic cavity function.

Risk assessment models developed from administrative and clinical databases are used for clinical decision making. Since these models are derived from a database, they have an inherent limitation of being as good as the data they are derived from. Many of these models under or overestimate certain clinical outcomes particularly mortality in certain group of patients. Undeniably, there is significant variability in all these models on account of patient population studied, the statistical analysis used to develop the model and the period during which these models were developed. This review aims to shed light on development and application of risk assessment models for cardiac surgery with special emphasis on risk stratification in severe aortic stenosis to select patients for transcatheter aortic valve replacement.

Transcatheter aortic valve replacement is a well-established alternative to surgical aortic valve replacement in high-risk patients with severe symptomatic aortic stenosis. Currently, this technique is shifting towards younger patient groups with intermediate- and low-risk profile, which raises the question about long-term durability. Despite acceptable results up to 5 years, little is currently known about valve performance beyond 5 years. Since valve deterioration, thrombosis and endocarditis seem to be the main factors affecting valve durability, precise and widely accepted definitions of these parameters were stated by the European Association of Percutaneous Cardiovascular Interventions (EAPCI) in 2017, followed by the Valve in Valve International Data (VIVID) group definitions in 2018 and the Valve Academic Research Consortium 3 (VARC-3) definitions in 2021. Until the introduction of these definitions, interstudy comparisons were difficult due to missing uniformity. Since the release of these recommendations, an increasing number of studies have reported their data on long-term durability using these new criteria. The aim of the present article is to discuss the current definitions on bioprosthetic valve durability, and to summarize the available data on long-term durability of transcatheter aortic valves.