Is the European System for Cardiac Operative Risk Evaluation model valid for estimating the operative risk of patients considered for percutaneous aortic valve replacement?

Risk Stratification for Transcatheter Aortic Valve Replacement

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.

Quantifying the Shift Toward Transcatheter Aortic Valve Replacement in Low-Risk Patients: A Meta-Analysis

BACKGROUND

In recent years, use of transcatheter aortic valve replacement has expanded to include patients at intermediate- and low-risk cohorts. We sought to determine disease prevalence and treatment distribution including transcatheter aortic valve replacement eligibility in low-risk patients across 37 advanced economies.

METHODS AND RESULTS

Four systematic searches were conducted across MEDLINE, EMBASE, and the Cochrane database for studies evaluating disease prevalence, severity, decision making, and survival in patients with aortic stenosis. Estimates of disease prevalence and treatment eligibility were calculated using stochastic simulation and population data for the 37 countries comprising the International Monetary Fund's advanced economies index. Fifty-six studies comprising 42 965 patients were included across 5 domains: prevalence, severity, symptom status, treatment modality, and outcome. The pooled prevalence in the general population aged 60 to 74 years and >75 years was 2.8% (95% confidence interval [CI], 1.4%-4.1%) and 13.1% (95% CI, 8.2%-17.9%), respectively-corresponding to an estimated 16.1 million (95% CI, 12.2-20.3) people in 37 advanced economies. Of these, an estimated 3.2 million (95% CI, 2.2-4.4) patients have severe aortic stenosis with 1.9 million (95% CI, 1.3-2.6) eligible for surgical aortic valve replacement. There are ≈485 230 (95% CI, 284 550-66 7350) high-risk/inoperable patients, 152 690 (95% CI, 73 410-263 000) intermediate-risk patients, and 378 890 (95% CI, 205 130-610 210) low-risk patients eligible for transcatheter aortic valve replacement.

CONCLUSIONS

With a prevalence of 4.5%, an estimated 16.1 million people aged ≥60 years across 37 advanced economies have aortic stenosis. Of these, there are ≈1.9 million patients eligible for surgical aortic valve replacement and 1.0 million patients eligible for transcatheter aortic valve replacement.

Addition of albumin to Traditional Risk Score Improved Prediction of Mortality in Individuals Undergoing Transcatheter Aortic Valve Replacement

OBJECTIVES

The ability of the Society of Thoracic Surgeons (STS) and European System for Cardiac Operative Risk Evaluation (EuroSCORE)-2 scores to predict outcomes after transcatheter aortic valve replacement (TAVR) is insufficient. Frailty and serum albumin as a frailty marker were shown to correlate with prognosis after TAVR. We sought to evaluate the additive value of serum albumin to STS and EuroSCORE-2 scores to predict mortality in individuals undergoing TAVR.

DESIGN

Retrospective analysis.

SETTING

Tertiary-care hospital prospective registry.

PARTICIPANTS

Individuals who underwent TAVR (N = 426).

MEASUREMENTS

We compared survival rates according to median baseline albumin levels (4 g/dL), STS score (4.5%), and EuroSCORE-2 (3.45%). Participants were divided into four groups according to median serum albumin and median STS and EuroSCORE-2 scores (high vs low), and 1-year survival rates were compared. A category-free net reclassification index (NRI) was calculated to compare the ability of a model of STS or EuroSCORE-2 alone to classify mortality risk with and without the addition of baseline serum albumin.

RESULTS

Participants with low albumin levels had higher mortality (hazard ratio (HR) = 3.03, 95% confidence interval (CI) = 1.66-5.26, P < .001). Participants with low serum albumin and a high STS (HR = 4.55, 95% CI = 2.21-9.38, P < .001) or EuroSCORE-2 (HR = 2.72, 95% CI = 1.48-5.06, P = .001) score had higher mortality. Using NRI analysis, a model that included albumin in addition to STS correctly reclassified 42% of events (NRI = 0.58) and a model that included albumin in addition to EuroSCORE-2 correctly reclassified 44% of events (NRI = 0.64).

CONCLUSION

Serum albumin, as a marker of frailty, can significantly improve the ability of STS and EuroSCORE-2 scores to predict TAVR-related mortality.

Preoperative Risk Levels and Vascular Access in Transcatheter Aortic Valve Implantation-A Single-Institute Analysis

Although transcatheter aortic valve implantation (TAVI) has been indicated for patients with high surgical risk, indications for or against the procedure become more difficult as vascular access becomes more proximal and/or invasive in order to accommodate patients with even higher risks. We compared preoperative factors including the European System for Cardiac Operative Risk Evaluation (EuroSCORE) and Society of Thoracic Surgeons Predicted Risk of Mortality (STS) score with postoperative survival in 195 patients undergoing TAVI during 2.5 years (January 2010 to June 2012), when vascular access routes were developed from iliofemoral (IL/Fm access, n = 149), axillo-clavicular, apical, and direct aortic approaches (alternative access, n = 46). Logistic regression analyses showed that alternative access was associated with reduced 30-day survival (P = 0.024), while high surgical risk (>15% in both EuroSCORE and STS score) was associated with reduced 1-year survival (P = 0.046). Thus, patients treated via IL/Fm access had acceptable outcome regardless of preoperative risk levels while patients with low surgical risk (<15%) had favorable outcome irrespective of access route. Since the remaining patients with combined risk factors, high preoperative risk level (>15%) requiring alternative access, had a prohibitive risk in our experience, they might have been considered untreatable or not amenable even to TAVI and offered medical or alternative managements.

Effect of Availability of Transcatheter Aortic-Valve Replacement on Clinical Practice

BACKGROUND

Since the adoption of transcatheter aortic-valve replacement (TAVR), questions have been raised about its effect on clinical practice in comparison with the effect of surgical aortic-valve replacement, which is considered the current standard of care. Complete nationwide data are useful in examining how the introduction of a new technique influences previous clinical standards.

METHODS

We analyzed data on characteristics of patients and in-hospital outcomes for all isolated TAVR and surgical aortic-valve replacement procedures performed in Germany from 2007 to 2013.

RESULTS

In total, 32,581 TAVR and 55,992 surgical aortic-valve replacement procedures were performed. The number of TAVR procedures increased from 144 in 2007 to 9147 in 2013, whereas the number of surgical aortic-valve replacement procedures decreased slightly, from 8622 to 7048. Patients undergoing TAVR were older than those undergoing surgical aortic-valve replacement (mean [±SD] age, 81.0±6.1 years vs. 70.2±10.0 years) and at higher preoperative risk (estimated logistic EuroSCORE [European System for Cardiac Operative Risk Evaluation], 22.4% vs. 6.3%, on a scale of 0 to 100%, with higher scores indicating greater risk and a score of more than 20% indicating high surgical risk). In-hospital mortality decreased in both groups between 2007 and 2013 (from 13.2% to 5.4% with TAVR and from 3.8% to 2.2% with surgical aortic-valve replacement). The incidences of stroke, bleeding, and pacemaker implantation (but not acute kidney injury) also declined.

CONCLUSIONS

The use of TAVR increased markedly in Germany between 2007 and 2013; the concomitant reduction in the use of surgical aortic-valve replacement was moderate. Patients undergoing TAVR were older and at higher procedural risk than those undergoing surgical aortic-valve replacement. In-hospital mortality decreased in both groups but to a greater extent among patients undergoing TAVR. (Funded by the Heart Center, Freiburg University.).

Is the EuroSCORE II best suited for reoperative risk estimation in patients with structural deterioration of aortic bioprostheses?

BACKGROUND

Operative risk prediction systems (logistic EuroSCORE I, EuroSCORE II and STS Score) are employed together with multidisciplinary discussion to contraindicate conventional surgery in patients with valvular heart disease and propose the employment of alternative transcatheter procedures. The EuroSCORE I has been reported to underperform in these circumstances; we hypothesize that the EuroSCORE II is best suited for the stratification of risk in patients with structural deterioration (SVD) of valvular bioprostheses and potential candidates to the Valve-in-Valve procedure (deployment of a transcatheter valve within a failing valvular bioprosthesis).

METHODS AND EVALUATION OF THE HYPOTHESIS

A multi-institutional collaboration is required to fully address such hypothesis. Therefore, we performed a preliminary validation study by retrieval of the complete records of 81 patients undergoing reoperative aortic valve replacement for preoperative diagnosis of bioprosthetic SVD at our Institution. Logistic EuroSCORE I, EuroSCORE II and STS Score were calculated by preoperatively available data. Faced to an observed reoperative mortality of 4.9%, average EuroSCORE I was 15.8%±13.4, EuroSCORE II was 7.3%±7.4 and the STS Score was 15%±9.8. The three systems provided sufficient adequacy (Hosmer-Lemeshow p=0.847, p=0.999 and p=0.9948, respectively). Yet, the area under the ROC curve was significantly higher for the EuroSCORE II (0.9903) vs. the EuroSCORE I (0.8994) (p=0.044). The STS Score yielded an intermediate figure (0.9643). The odds ratios (logistic regression) were 1.079 for EuroSCORE I, 1.223 for the STS Score and 1.474 for EuroSCORE II.

CONCLUSIONS

The three investigated algorithms showed reasonable calibration in the prediction of mortality for reoperative aortic valve replacement, but they evenly overestimated the observed mortality. The hypothesis that the EuroSCORE II is better suited for the selection of candidates to Valve-in-Valve implantation is worth of further multi-institutional investigations on the basis of our preliminary findings and due to the expanding role of transcatheter techniques.

Comparison of outcomes of patients with left ventricular ejection fractions ≤30% versus ≥30% having transcatheter aortic valve implantation (from the German Transcatheter Aortic Valve Interventions Registry)

Transcatheter aortic valve implantation (TAVI) is rapidly evolving in Germany. Especially severe reduced left ventricular ejection fraction (LVEF) is known as a prominent risk factor for adverse outcome in open heart surgery. Thus, the data of the prospective multicenter German Transcatheter Aortic Valve Interventions Registry were analyzed for outcomes in patients with severe depressed LVEF. Data of 1,432 patients were consecutively collected after transcatheter aortic valve implantation. Patients were divided into 2 groups (A: LVEF ≤30%, n = 169, age 79.9 ± 6.7 years, logES 34.2 ± 17.8%; B: LVEF >30%, n = 1,263, age 82.0 ± 6.1 years, logES 18.9 ± 12.0%), and procedural success rates, New York Heart Association classification, and quality of life were compared at 30 days and 1 year, respectively. Technical success was achieved in 95.9% (A) and 97.6% (B). Survival and the New York Heart Association classification at 30 days demonstrated an excellent outcome in both groups. There was a significant improvement according to the self-assessment in health condition (0 to 100 scale) with a much larger gain in group A (28 vs 19 patients, p <0.0001). Nevertheless, low cardiac output syndrome (12.3% vs 5.9%, p <0.01) and resuscitation (10.4% vs 5.6%, p <0.05) were more frequently seen in group A, contributing to a higher mortality at 30 days (14.3% vs 7.2%) and 1 year (33.7% vs 18.1%, p <0.001). In conclusion, this real-world registry demonstrated a comparably high success rate for patients with severe reduced LVEF and an early improvement in functional status as demonstrated by substantial benefit, despite a doubled postprocedural mortality.

Assessing the risk of aortic valve replacement for severe aortic stenosis in the transcatheter valve era

Surgical aortic valve replacement had been the only definitive treatment of severe aortic stenosis before the availability of transcatheter valve technology. Historically, many patients with severe aortic stenosis had not been offered surgery, largely related to professional and patient perception regarding the risks of operation relative to anticipated benefits. Such patients have been labeled as "high risk" or "inoperable" with respect to their suitability for surgery. The availability of transcatheter aortic valve replacement affords a new treatment option for patients previously not felt to be optimal candidates for surgical valve replacement and allows for the opportunity to reexamine the methods for assessing operative risk in the context of more than 1 available treatment. Standardized risk assessment can be challenging because of both the imprecision of current risk scoring methods and the variability in ascertaining risk related to operator experience as well as local factors and practice patterns at treating facilities. Operative risk in actuality is not an absolute but represents a spectrum from very low to extreme, and the conventional labels of high risk and inoperable are incomplete with respect to their utility in clinical decision making. Moving forward, the emphasis should be on developing an individual assessment that takes into account procedure risk as well as long-term outcomes evaluated in a multidisciplinary fashion, and incorporating patient preferences and goals in a model of shared decision making.

Geriatric cardiac surgery: chronology vs. biology

Cardiac surgery is increasingly performed in elderly patients, and whilst the incidence of common risk factors associated with poorer outcome increases with age, recent studies suggest that outcomes in this population may be better than is widely appreciated. As such, in this review we have examined the current evidence for common cardiac surgical procedures in patients aged over 70 years. Coronary artery bypass grafting (CABG) in the elderly has similar early safety to percutaneous intervention, though repeat revascularisation is lower. Totally avoiding instrumentation of the ascending aorta with off-pump techniques may also reduce the incidence of neurological injury. Aortic valve replacement (AVR) significantly improves quality of life and provides excellent short- and long-term outcomes. Combined AVR and CABG carries higher risk but late survival is still excellent. Mini-sternotomy AVR in the elderly can provide comparable survival to full-sternotomy AVR. More accurate risk stratification systems are needed to appropriately select patients for transcatheter aortic valve implantation. Mitral valve repair is superior to replacement in the elderly, although choosing the most effective method is important for achieving maximal quality of life. Minimally-invasive mitral valve surgery in the elderly has similar postoperative outcomes to sternotomy-based surgery, but reduces hospital length of stay and return to activity. In operative candidates, surgical repair is superior to percutaneous repair. Current evidence indicates that advanced age alone is not a predictor of mortality or morbidity in cardiac surgery. Thus surgery should not be overlooked or denied to the elderly solely on the basis of their "chronological age", without considering the patient's true "biological age".

Clinical impact of paravalvular leaks on biomarkers and survival after transcatheter aortic valve implantation

BACKGROUND

There is accumulating evidence that up to 20% of the implanted devices after TAVI are associated with a significant degree of paravalvular leaks, which appear to be associated with a negative clinical outcome.

METHODS

A total of 355 patients with severe aortic valvular stenosis (AVS) were treated by TAVI (Corevalve n = 222, Edwards Sapien n = 133). Survival, NT-proBNP and the grade of PVL were quantified up to 12 months after implantation.

RESULTS

Technical success rate was 97.8%. Thirty-day mortality was 9.6%. Post-procedural transvalvular aortic regurgitation was seen only in a minority of cases (5%), whereas PVL were frequently observed (grade: <1+ in 58.2%, ≥1-<2 in 33.9%, and ≥2 in 7.9%). There was a clear relation-ship between PVL and adverse outcome (P < 0.001). After a transient increase, NT-proBNP showed a significant decline. Interestingly, a PVL ≥2+ was associated with a much higher rise in NT-proBNP compared to the other groups (P < 0.01), and a post-procedural increase in NT-proBNP by more than 1640 ng L(-1) within 5 days was associated with a significant increase in rate of death (P < 0.01).

CONCLUSIONS

TAVI is an efficient treatment option for high-risk patients with severe AVS. The incidence of PVL is an inacceptable clinical problem. Serial measurement of NT-proBNP can be used for risk-stratification in patients with a significant PVL. In general, PVL graded ≥2+ is associated with a dramatically increased 6-month mortality. Therefore, any action to reduce paraprosthetical regurgitation is highly recommended.

Simple bedside clinical evaluation versus established scores in the estimation of operative risk in valve replacement for severe aortic stenosis

BACKGROUND

The operative risk of cardiac surgery is ascertained preoperatively on the basis of scores validated in multinational studies. However, the value they add to a simple bedside clinical evaluation (CE) remains controversial.

AIMS

To compare operative mortality (defined as death from all causes before the 31st postoperative day) predicted by CE with that predicted by additive and logistic EuroSCOREs, EuroSCORE II and Society of Thoracic Surgeons (STS), Ambler and age-creatinine-ejection fraction (ACEF) scores in patients undergoing aortic valve replacement (AVR) for severe aortic stenosis.

METHODS

Overall, 314 consecutive patients were included who underwent AVR between October 2009 and November 2011 (22% with coronary artery bypass graft); mean age 73.4 ± 9.7 years (29% aged>80 years). Based on CE, patients were divided into four predefined groups of increasing estimated mortality risk: I ≤ 3.9%; II 4-6.9%; III 7-9.9%; IV ≥ 10%. The positive and negative predictive values of the six scores and CE were compared.

RESULTS

The observed overall operative mortality was 5.7%. The distribution of the four predicted mortality groups by each score was highly variable. The positive predictive value, calculated for the 64 patients classified at highest risk by CE (groups III or IV) or each score, was 17.2% for EuroSCORE II, 14.1% for CE and STS scores, 10.9% for additive and logistic EuroSCOREs, 10.6% for ACEF and 10.2% for Ambler. The positive predictive value of each score in the low-risk groups (I and II) ranged from 2.8% to 4.4%.

CONCLUSION

A simple bedside CE appears as reliable as the various established scores for predicting operative risk in patients undergoing surgical aortic valve replacement. The development and validation of more comprehensive risk stratification tools, including risk factors thus far neglected, seems warranted.

Outcomes of consecutive patients referred for consideration for transcatheter aortic valve implantation from an encompassing health-care region

Procedural outcomes for transcatheter aortic valve implantation (TAVI) are well described. However, limited information exists regarding patient screening and selection. Thus, the purpose of the study was to review consecutive patients referred for TAVI from an inclusive-defined population. The Mazankowski Alberta Heart Institute TAVI program has maintained a prospective database on all referred patients. Patients are reviewed in outpatient clinic attended by a nurse, cardiologist, cardiac surgeon, and administrative assistant. After workup is complete, a TAVI Heart Team conference occurs to accept or reject each patient. Since November 2009, 276 patients (145 men and 131 women) have been referred with a steady increase in the number of referrals annually. Mean age was 82.2 years (men 81.6 and women 82.8), with 13% aged <70 years. Mean EuroSCORE was 13.8 and mean STS score was 5.7. Of the referred patients, 34% received TAVI, 17% were rejected, 12% underwent open AVR, 10% refused TAVI, and 27% are currently being assessed or followed. There were no differences in the mean EuroSCORE (13.4 vs 14.3; p = 0.64) or STS scores (5.2 vs 6.4; p = 0.13) of those accepted for TAVI versus those who were not. In conclusion, a team-based approach to assess this complex patient population is essential to ensure efficient and comprehensive evaluation, in turn determining appropriate care allocation. With expansion of clinical experience and the evidence supporting TAVI, the Heart Teams defined to assess this patient population will be burdened with increased clinical commitment and require appropriate support.

Performance analysis of EuroSCORE II compared to the original logistic EuroSCORE and STS scores for predicting 30-day mortality after transcatheter aortic valve replacement

The original European System for Cardiac Operative Risk Evaluation (EuroSCORE) has been recently updated as EuroSCORE II to optimize its efficacy in cardiac surgery, but its performance has been poorly evaluated for predicting 30-day mortality in patients who undergo transcatheter aortic valve replacement (TAVR). Consecutive patients (n = 250) treated with TAVR were included in this analysis. Transapical access was used in 60 patients, while 190 procedures were performed using a transfemoral approach. Calibration (risk-adjusted mortality ratio) and discrimination (C-statistic and U-statistic) were calculated for the logistic EuroSCORE, EuroSCORE II, and Society of Thoracic Surgeons (STS) scores for predicting 30-day mortality. Observed mortality was 7.6% in the overall population (6.3% and 11.7% for the transfemoral and transapical cohorts, respectively). Predicted mortality was 22.6 ± 12.8% by logistic EuroSCORE, 7.7 ± 5.8% by EuroSCORE II, and 7.3 ± 4.1% by STS score. The risk-adjusted mortality ratio was 0.34 (95% confidence interval [CI] 0.10 to 0.58) for logistic EuroSCORE, 0.99 (95% CI 0.29 to 1.69) for EuroSCORE II, and 1.05 (95% CI 0.30 to 1.79) for STS score. Moderate discrimination was observed with EuroSCORE II (C-index 0.66, 95% CI 0.52 to 0.79, p = 0.02) compared to the logistic EuroSCORE (C-index 0.63, 95% CI 0.51 to 0.76, p = 0.06) and STS (C-index 0.58, 95% CI 0.43 to 0.73, p = 0.23) score, without a significant difference among the 3 risk scores. Discrimination was slightly better in the transfemoral cohort compared to the transapical cohort with the 3 risk scores. In conclusion, EuroSCORE II and the STS score are better calibrated than the logistic EuroSCORE but have moderate discrimination for predicting 30-day mortality after TAVR.

Long-term outcomes of isolated aortic valve replacement and concomitant AVR and coronary artery bypass grafting

BACKGROUND

It is well established that concomitant aortic valve replacement (AVR) and coronary artery bypass grafting (CABG) has a higher operative mortality rate than isolated AVR. However, studies report conflicting results on the long-term mortality. The aim of this prospective study was to explore and compare the outcomes and risk factors of isolated AVR and concomitant AVR and CABG in a consecutive Dutch patient population.

METHODS

From January 2001 through January 2010, 332 consecutive patients underwent AVR with or without CABG at a single institution (197 isolated AVR and 135 concomitant AVR and CABG). A multivariate Cox proportional hazard analysis was performed to determine the independent risk factors for long-term mortality after aortic valve replacement.

RESULTS

All 332 consecutive, referred patients who underwent aortic valve surgery were followed for up to 10 years. Median follow-up length was 48 months. The population had a median age of 73 years (IQR 65-78) and predominantly consisted of males (62%). Patients in the combined AVR and CABG group were older, had worse cardiac risk profiles and had worse preoperative cardiac statuses than those receiving isolated AVR. Five-year survival was 85% in AVR and 73% in AVR-CABG (p-value 0.012). Independent risk factors for mortality were higher creatinine values, previous CABG and increasing age.

CONCLUSION

Unselected, consecutive patients who underwent aortic valve replacement surgery and who received concomitant bypass surgery between 2001-2010 had higher 5-year mortality than their counterparts without CABG. Prior CABG, renal function, age but not concomitant CABG remained independently associated with increased mortality. Finally, the observed mortality rate in this consecutive patient group compared favourably with preoperative risk assessment using the EuroSCORE.

EuroScore 2 for identification of patients for transapical aortic valve replacement--a single center retrospective in 206 patients

Background

Operative risk scoring algorithms identify patients with severe AS for transcatheter valve implantation in whom the anticipated operative mortality for conventional surgery would be considered prohibitive. We compared the three risk scores EuroScore 1 (LES), society of thoracic surgeons’ (STS) score and ACEF (age-creatinine-ejection fraction score) to the readjusted EuroScore 2 recently presented.

Methods

We reviewed all consecutive patients receiving either isolated conventional aortic valve replacement (cAVR) or transapical aortic valve implantation (TA-TAVI) in a two-year period (n = 206). 30-days mortality was considered as primary endpoint.

Results

TA-TAVI was performed in 76 patients, isolated cAVR in 130 patients. Overall mortality was 4.4% (TA-TAVI: 7.9%; cAVR: 2.3%). EuroScore 2 showed a good estimation for the entire population as well as within the subgroups: 4,02 ± 5,36% (TA-TAVI: 6.16 ± 7.14%, cAVR: 2.77 ± 3.42%). Predicted mortalities as assessed by LES were largely overestimated (TA-TAVI: 27.4 ± 20.9% cAVR: 10.6 ± 10.6%, sensitivity: 0.89, specificity: 0.71). STS predicted mortality was 6.3 ± 4.4% for TA-TAVI patients as to 3.2 ± 3.1% for cAVR patients (sens.: 0.22, spec.: 0.96) and ACEF predicted a mortality of 1.16 ± 0.36% for cAVR and 1.58 ± 0.59% for TA-TAVI patients (sens.: 0.78, spec.: 0.89).

Conclusion

The newly refined EuroScore 2 showed a good correlation within the studied population. For the individual patient, new cut-offs will have to be defined to triage patients for TAVI procedure. A drawback for complex score systems such as EuroScore and STS is the lack of recalibration to smaller populations as encountered in even large single centers.

Minimally invasive surgery for aortic stenosis in the geriatric patient: where are we now?

Minimally invasive aortic valve surgery has evolved with time and become the routine approach for aortic surgery in select surgical centers. The success of these procedures in the nonelderly has led some to embark on using minimal access techniques in the geriatric population as well. With the geriatric community often inflicted with the greatest disease burden, suffering not only from a valvular process but also cumulative comorbidities, geriatric patients may be the patients most likely to derive benefit from a minimally invasive approach. Alternative therapies for symptomatic aortic stenosis include conventional full-sternotomy aortic valve replacement in addition to transcatheter aortic valve implantation. Each option has its advantages and disadvantages. The role of minimal access aortic valve surgery and its impact on the progressively aging population in the face of conventional surgery and transcatheter technology is discussed.

Transcatheter aortic valve replacement: the changing paradigm of aortic stenosis treatment

Aortic stenosis is the most common cause for valvular surgery in the USA. For nearly 50 years, surgical aortic valve replacement has been the standard of care for symptomatic patients; unfortunately, a significant number of patients are not referred to surgery owing to advanced comorbidities and age. Transcatheter aortic valve replacement has emerged as an effective therapy for patients at high risk for surgery. Through device innovations and accumulated experience, the safety and efficacy of the procedure has improved since its inception. Transcatheter valve replacement has been found superior to medical therapy in inoperable patients with aortic stenosis, yet many questions remain as to which patients are appropriate for this exciting and novel therapy.

Understanding risk assessment in cardiac surgery patients

Understanding the risk of surgery in valvular disease is of interest because aging of the population renders decision making more difficult and the magnitude of risk will influence not only the decision to intervene but also the choice of intervention and its timing. To assist clinicians in assessing the risk of cardiac surgery, multivariate risk scores are increasingly used to estimate operative mortality. Overall, the currently available scores, mostly U.S. Society of Thoracic Surgeons score and European System for Cardiac operative Risk Evaluation, achieve acceptable discrimination but suboptimal calibration in estimating the operative mortality of heart valve surgery. The intrinsic limitations of scoring systems highlight the fact that risk scores should be integrated into clinical judgment but should not be a substitute for it. A multidisciplinary approach involving cardiologists, cardiac surgeons, and anesthesiologists is required for this purpose, especially in high-risk patients.

[Transcutaneous aortic valve implantation: Anesthetic and perioperative management]

OBJECTIVE

To describe the perioperative management, from the point of view of the anesthesia-intensive care unit specialist, of patients with aortic stenosis who undergo transcatheter aortic valve implantation (femoral or apical TAVI).

DATA SOURCE

The PubMed database (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) was queried, using the following keywords: aortic stenosis, transcatheter aortic valve implantation TAVI, outcome, complications, anesthesia.

DATA SYNTHESIS

TAVI is performed in patients suffering from aortic stenosis and presenting with numerous comorbidities, high-predicted perioperative mortality and/or contraindications to conventional cardiac surgery. TAVI is performed either by percutaneous transfemoral or transapical puncture of the left ventricle (LV) apex. These patients are older, have more comorbidities than those undergoing aortic valve replacement surgery and perioperative mortality predicted by risk scores is higher. While transapical TAVI is performed with general anaesthesia, transfemoral TAVI can be performed with either general or locoregional anaesthesia and/or sedation. The choice of the anaesthetic technique for transfemoral TAVI depends on the patient's medical history, the technique chosen for valve implantation, the type of monitoring and the anticipated hemodynamic problems. The incidence of complications following TAVI is high, some are common to surgical aortic valve replacement, and others are specific to this technique. Because of the prevalence of comorbidities, the hemodynamic-specific constraints of this technique and the incidence of complications, anaesthetic and perioperative management (evaluation, anaesthetic technique, monitoring, post-surgery care) requires the same level of expertise as in cardiac surgery anaesthesia.

CONCLUSION

TAVI expands treatment options for patients with aortic valve stenosis. The anaesthesia team must be involved in the care of these patients with the same level of expertise and care as in heart surgery on critical patients.

Effect of experience on results of transcatheter aortic valve implantation using a Medtronic CoreValve System

Outcome after transcatheter aortic valve implantation (TAVI) depends on the patient risk profile, operator experience, progress in technology, and technique. We sought to compare the results of TAVI during the initiation phase and after certification to perform TAVI with the Medtronic CoreValve System without proctoring. A total of 165 consecutive patients was categorized into a first cohort of 33 patients treated before certification (November 2005 to December 2007) and a second cohort of 132 patients treated after certification (January 2008 to October 2010). The study end points were selected and defined according to the Valve Academic Research Consortium recommendations. Compared to cohort 2, the patients in cohort 1 more frequently had New York Heart Association class III-IV (100% vs 71%, p <0.001), hypertension (67% vs 39%, p = 0.004), and aortic regurgitation grade III-IV (46% vs 22%, p = 0.006) before TAVI. Over time, the patients in cohort 2 more frequently underwent a truly percutaneous approach (98% vs 82%, p = 0.002) without circulatory support (96% vs 67%, p <0.001) but with more concomitant percutaneous coronary intervention (11% vs 0%, p = 0.042) than the patients in cohort 1. They also more often received a 29-mm prosthesis (72% vs 24%, p <0.001), required less postimplantation balloon dilation (10% vs 27%, p = 0.008), and had less aortic regurgitation grade III-IV after TAVI (12% vs 30%, p = 0.010). The clinical outcome showed a nonsignificant reduction in the combined safety end point (30% to 17%) but a significant reduction in cerebrovascular events (21% to 7%, p = 0.020) and life-threatening bleeding (15% to 5%, p = 0.044) in cohort 2. However, the reduction in overall bleeding and vascular complications (25% and 14%, respectively) was not significant. In conclusion, TAVI became significantly less complex and was associated with better results over time but remained associated with a high frequency of periprocedural major cardiovascular complications.

ESC Working Group on Valvular Heart Disease Position Paper: assessing the risk of interventions in patients with valvular heart disease

AIMS

Risk scores provide an important contribution to clinical decision-making, but their validity has been questioned in patients with valvular heart disease (VHD), since current scores have been mainly derived and validated in adults undergoing coronary bypass surgery. The Working Group on Valvular Heart Disease of the European Society of Cardiology reviewed the performance of currently available scores when applied to VHD, in order to guide clinical practice and future development of new scores.

METHODS AND RESULTS

The most widely used risk scores (EuroSCORE, STS, and Ambler score) were reviewed, analysing variables included and their predictive ability when applied to patients with VHD. These scores provide relatively good discrimination, i.e. a gross estimation of risk category, but cannot be used to estimate the exact operative mortality in an individual patient because of unsatisfactory calibration.

CONCLUSION

Current risk scores do not provide a reliable estimate of exact operative mortality in an individual patient with VHD. They should therefore be interpreted with caution and only used as part of an integrated approach, which incorporates other patient characteristics, the clinical context, and local outcome data. Future risk scores should include additional variables, such as cognitive and functional capacity and be prospectively validated in high-risk patients. Specific risk models should also be developed for newer interventions, such as transcatheter aortic valve implantation.

Incidence and predictors of early and late mortality after transcatheter aortic valve implantation in 663 patients with severe aortic stenosis

BACKGROUND

There is a lack of information on the incidence and predictors of early mortality at 30 days and late mortality between 30 days and 1 year after transcatheter aortic valve implantation (TAVI) with the self-expanding CoreValve Revalving prosthesis.

METHODS AND RESULTS

A total of 663 consecutive patients (mean age 81.0 ± 7.3 years) underwent TAVI with the third generation 18-Fr CoreValve device in 14 centers. Procedural success and intraprocedural mortality were 98% and 0.9%, respectively. The cumulative incidences of mortality were 5.4% at 30 days, 12.2% at 6 months, and 15.0% at 1 year. The incidence density of mortality was 12.3 per 100 person-year of observation. Clinical and hemodynamic benefits observed acutely after TAVI were sustained at 1 year. Paravalvular leakages were trace to mild in the majority of cases. Conversion to open heart surgery (odds ratio [OR] 38.68), cardiac tamponade (OR 10.97), major access site complications (OR 8.47), left ventricular ejection fraction <40% (OR 3.51), prior balloon valvuloplasty (OR 2.87), and diabetes mellitus (OR 2.66) were independent predictors of mortality at 30 days, whereas prior stroke (hazard ratio [HR] 5.47), postprocedural paravalvular leak ≥ 2+ (HR 3.79), prior acute pulmonary edema (HR 2.70), and chronic kidney disease (HR 2.53) were independent predictors of mortality between 30 days and 1 year.

CONCLUSIONS

Benefit of TAVI with the CoreValve Revalving System is maintained over time up to 1 year, with acceptable mortality rates at various time points. Although procedural complications are strongly associated with early mortality at 30 days, comorbidities and postprocedural paravalvular aortic regurgitation ≥ 2+ mainly impact late outcomes between 30 days and 1 year.

Performance of Four Risk Algorithms in Predicting Intermediate Survival in Patients Undergoing Aortic Valve Replacement

Objective

Several risk models exist to predict operative outcomes after cardiac surgery and are used in selecting patients for alternative procedures such as transcatheter valve implantation. We sought to evaluate the performance of the Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) model in accurately identifying patients at high risk for aortic valve replacement (AVR).

Methods

Three hundred and ninety four consecutive patients who underwent isolated AVR from January 1, 2001, to July 1, 2007, at a tertiary care center were analyzed using the STS database. Patients were stratified into tertiles according to operative surgical risk calculated by the four models [STS-PROM, European system for cardiac operative risk evaluation (EuroSCORE), Ambler, and Providence]. Vital status at 1 year was determined using the National Death Index and Social Security Death Index.

Results

There were 310 low-risk patients, 56 intermediate-risk patients, and 28 high-risk patients with respect to the STS-PROM. The predicted risk of death for the low-risk, intermediate-risk, and high-risk groups were 2.4% ± 1.1%, 6.9% ± 1.4%, 15.8% ± 7.6% (P < 0.001) with respect to the STS-PROM model. Actual operative mortality for each respective group was 1.94%, 5.36%, 14.29% (P < 0.001) and 1-year mortality was 3.23%, 12.50%, 21.43% (P < 0.001), respectively.

Conclusions

High-risk patients have significantly high mortality after AVR. The STS-PROM accurately predicts operative mortality and can be used to predict 1-year survival as well. This risk model may be preferentially used instead of the EuroSCORE.

Comparison between transcatheter and surgical prosthetic valve implantation in patients with severe aortic stenosis and reduced left ventricular ejection fraction

BACKGROUND

Patients with severe aortic stenosis and reduced left ventricular ejection fraction (LVEF) have a poor prognosis with conservative therapy but a high operative mortality when treated surgically. Recently, transcatheter aortic valve implantation (TAVI) has emerged as an alternative to surgical aortic valve replacement (SAVR) for patients considered at high or prohibitive operative risk. The objective of this study was to compare TAVI and SAVR with respect to postoperative recovery of LVEF in patients with severe aortic stenosis and reduced LV systolic function.

METHODS AND RESULTS

Echocardiographic data were prospectively collected before and after the procedure in 200 patients undergoing SAVR and 83 patients undergoing TAVI for severe aortic stenosis (aortic valve area ≤1 cm(2)) with reduced LV systolic function (LVEF ≤50%). TAVI patients were significantly older (81±8 versus 70±10 years; P<0.0001) and had more comorbidities compared with SAVR patients. Despite similar baseline LVEF (34±11% versus 34±10%), TAVI patients had better recovery of LVEF compared with SAVR patients (ΔLVEF, 14±15% versus 7±11%; P=0.005). At the 1-year follow-up, 58% of TAVI patients had a normalization of LVEF (>50%) as opposed to 20% in the SAVR group. On multivariable analysis, female gender (P=0.004), lower LVEF at baseline (P=0.005), absence of atrial fibrillation (P=0.01), TAVI (P=0.007), and larger increase in aortic valve area after the procedure (P=0.01) were independently associated with better recovery of LVEF.

CONCLUSION

In patients with severe aortic stenosis and depressed LV systolic function, TAVI is associated with better LVEF recovery compared with SAVR. TAVI may provide an interesting alternative to SAVR in patients with depressed LV systolic function considered at high surgical risk.