***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Patients with severe aortic stenosis and coexisting non-cardiac conditions may be at high risk for surgical replacement of the aortic valve or even be no c and i date s for surgery . In these patients , transcatheter aortic valve implantation ( TAVI ) is suggested as an alternative . Results of the PARTNER ( Placement of AoRTic TraNscathetER Valve ) trial comparing the clinical effectiveness of TAVI with surgical valve replacement and st and ard therapy were published . The authors assessed the cost-effectiveness of TAVI  in Belgium . Methods A Markov model of incremental costs , effects ( survival and quality of life ) and incremental cost-effectiveness of TAVI was developed . The impact on survival , number of events and quality of life was based on the PARTNER trial . Costs per event were context specific . Results In high-risk operable patients , even if the minor differences in 30-day and 1-year mortality are taken into account , the incremental cost-effectiveness ratio ( ICER ) remains on average above € 750 000 per quality -adjusted life-year ( QALY ) gained ( incremental cost : € 20 400 ; incremental effect : 0.03 QALYs ) . In inoperable patients , an ICER of € 44 900 per QALY ( incremental cost : € 33 200 ; incremental effect : 0.74 QALYs ) is calculated , including a life-long extrapolation of the mortality benefit . This result was sensitive to the assumed time horizon . The subgroup of anatomically inoperable patients had better outcomes than medically inoperable patients , with ICERs decreasing more than € 10 000/QALY . Conclusions It is inappropriate to consider reimbursement of TAVI for high-risk operable patients . Reimbursing TAVI in inoperable patients in essence is a political decision . From an economic perspective , it would be prudent to first target patients that are inoperable because of anatomical prohibitive conditions . In the search for evidence , the authors identified non-published negative results from a r and omised controlled TAVI trial . The study sponsor should be more willing to share this information to allow balanced evaluations and policy recommendations . Payers should require these data before taking reimbursement decisions Objective To determine the cost-effectiveness of transcatheter aortic valve implantation ( TAVI ) compared with surgical aortic valve replacement ( SAVR ) in a high-risk aortic stenosis ( AS ) population . Design A cost-utility analysis employing the National Institute of Clinical Excellence ( NICE ) reference case design for technology appraisal s. Setting The perspective of the UK National Health Service . Patients Utility data from a UK high-risk AS population .  TAVI and SAVR effectiveness was taken from the PARTNER A r and omised controlled trial . Main outcome measures Costs modelled over a 10 year horizon using a Markov model . Incremental cost-effectiveness ratios and cost-effectiveness acceptability curve were calculated with reference to the NICE willingness to pay per quality adjusted life year ( QALY ) gain threshold . Deterministic and probabilistic sensitivity analyses performed . Results Despite greater procedural costs ( £ 16 500 vs £ 9,256 ) , TAVI was cost-effective compared with SAVR over the 10 year model horizon ( costs £ 52 593 vs £ 53 943 and QALYs 2.81 vs 2.75 ) , indicating that TAVI dominated SAVR . This appeared to be due to greater postsurgical costs , related to the length and cost of hospital stay . The results appeared robust to a number of deterministic sensitivity and probabilistic analyses . The cost-effectiveness acceptability curve indicated that at the NICE £ 20 000 willingness to pay threshold per QALY gained , TAVI had a 64.6 % likelihood of being cost-effective , compared with 35.4 % for SAVR . Conclusions TAVI is likely to be a cost-effective treatment for high-risk patients with AS compared with the reference st and ard of SAVR . However , uncertainty surrounding the long-term outcomes for TAVI  patients remains ; this could have a substantive impact on estimates of cost-effectiveness Abstract Objective : The only effective treatment for severe aortic stenosis ( AS ) is valve replacement . However , many patients with co-existing conditions are ineligible for surgical valve replacement , historically leaving medical management ( MM ) as the only option which has a poor prognosis . Transcatheter Aortic Valve Replacement ( TAVR ) is a less invasive replacement method . The objective was to estimate cost-effectiveness of TAVR via transfemoral access vs MM in surgically inoperable patients with severe AS from the Canadian public healthcare system perspective . Methods : A cost-effectiveness analysis of TAVR vs MM was conducted using a deterministic decision analytic model over a 3-year time horizon . The PARTNER r and omized controlled trial results were used to estimate survival , utilities , and some re source utilization . Costs included the valve replacement procedure , complications , hospitalization , outpatient visits/tests , and home/nursing care . Re sources were valued ( 2009 Canadian dollars ) using costs from the Ontario Case Costing Initiative ( OCCI ) , Ontario Ministry of Health and Long-Term Care and Ontario Drug Benefits Formulary , or were estimated using relative costs from a French economic evaluation or clinical experts . Costs and outcomes were discounted 5 % annually . The effect of uncertainty in model parameters was explored in deterministic and probabilistic sensitivity analysis . Results : The incremental cost-effectiveness ratio ( ICER ) was $ 32,170 per quality -adjusted life year ( QALY ) gained for TAVR vs MM . When the time horizon was shortened to 24 and 12 months , the ICER increased to $ 52,848 and $ 157,429 , respectively . All other sensitivity analysis returned an ICER of less than $ 50,000/QALY gained . Limitations : A limitation was lack of availability of Canadian-specific re source and cost data for all re sources , leaving one to rely on clinical experts and data from France to inform certain parameters . Conclusions : Based on the results of this analysis , it can be concluded that TAVR is cost-effective compared to MM for the treatment of severe AS in surgically inoperable patients OBJECTIVE With increased life expectancy and improved technology , valve replacement is being offered to increasing numbers of elderly patients with satisfactory clinical results . By using st and ard econometric techniques , we estimated the relative cost-effectiveness of aortic valve replacement by drawing on a large prospect i ve data base at our institution . By using aortic valve replacement as an example , this introductory report paves the way to more definitive studies of these issues in the future . METHODS From 1961 to 2003 , 4617 adult patients underwent aortic valve replacement at our service . These patients were provided with a prospect i ve lifetime follow-up . As of 2005 , these patients had accumulated 31,671 patient-years of follow-up ( maximum 41 years ) and had returned 22,396 yearly question naires . A statistical model was used to estimate the future life years of patients who are currently alive . In the absence of direct estimates of utility , quality -adjusted life years were estimated from New York Heart Association class . The cost-effectiveness ratio was calculated by the patient 's age at surgery . RESULTS The overall cost-effectiveness ratio was approximately 13,528 dollars per quality -adjusted life year gained . The cost-effectiveness ratio increased according to age at surgery , up to 19,826 dollars per quality -adjusted life year for octogenarians and 27,182 dollars per quality -adjusted life year for nonagenarians . CONCLUSIONS Given the limited scope of this introductory study , aortic valve replacement is cost-effective for all age groups and is very cost-effective for all but the most elderly according to st and ard econometric rules of thumb BACKGROUND Major scores for the evaluation of procedural risk in cardiac surgery are the European system for cardiac operative risk evaluation score ( EuroSCORE ) , the Society of Thoracic Surgeons ( STS ) score , and the Parsonnet score . The aim of our study was to analyze the predictive value of these scores in " high risk " patients undergoing isolated aortic valve replacement ( AVR ) .  METHODS Six hundred and fifty-two patients underwent isolated AVR from January 1999 through June 2007 . Emergency and redo operations were included ; acute endocarditis was excluded . Evaluation was performed by logistic regression analysis . Data collection was prospect i ve . RESULTS The mean logistic EuroSCORE of all patients was 8.5 + /- 7.9 % , the mean STS score was 4.4 + /- 3.9 % , and the mean logistic Parsonnet score was 9.8 + /- 8.5 % . In-hospital mortality was 2.5 % ( n = 16 ) . Freedom from all-cause death was 93.4 % at 1 year , 90.2 % at 2 years , and 75.8 % at 5 years , respectively . A total of 182 patients had a logistic EuroSCORE greater than 10 . For the group of patients with a EuroSCORE between 10 % and 20 % ( n = 130 ) the mean EuroSCORE was 13.9 + /- 2.8 % and the STS score was 6.5 + /- 3.8 % . Observed mortality was 4.6 % in this group . For the 52 patients with a logistic EuroSCORE of at least 20 ( mean 28.5 + /- 10.3 % , STS score 10.1 + /- 7.3 % ) the observed mortality was 3.9 % ( n = 2 ) . By stepwise logistic regression , none of the EuroSCORE variables could be identified as an independent predictor in the " high- risk " group . CONCLUSIONS The logistic EuroSCORE was primarily created to allow patient grouping for the total spectrum of cardiac surgery . In patients undergoing isolated AVR , the EuroSCORE highly overestimates mortality , whereas the STS score seems to be actually more suitable in assessing perioperative mortality for these patients BACKGROUND The incremental cost-effectiveness of transapical transcatheter aortic valve implantation ( TAVI )  is ill-defined in high-risk patients where aortic valve replacement ( AVR ) is an option , and has not been ascertained outside a r and omized controlled trial . METHODS We developed a Markov model to examine the progression of patients between health states , defined as peri- and post-procedural , post-complication , and death . The mean and variance of risks , transition probabilities , utilities and cost of transapical TAVI , high-risk AVR , and medical management were derived from analysis of relevant registries . Outcome and cost were derived from 10,000 simulations . Sensitivity analyses further evaluated the impact of mortality , stroke , and other commonly observed outcomes . RESULTS In the reference case , both transapical TAVI and high-risk AVR and TAVI were cost-effective when compared to medical management ( $ 44,384/QALY and $ 42,637/QALY , respectively ) . Transapical TAVI failed to meet accepted criteria for incremental cost-effectiveness relative to AVR , which was the dominant strategy . In sensitivity analyses , the mortality rates related to the two strategies , the utilities post-AVR and post-transapical TAVI , and the cost of transapical TAVI  , were the main drivers of model outcome . CONCLUSION Transapical TAVI did not satisfy current metrics of incremental cost-effectiveness relative to high-risk AVR in the reference case . However , it may provide net health benefits at acceptable cost in selected high-risk patients among whom AVR is the st and ard intervention BACKGROUND Many patients with severe aortic stenosis and coexisting conditions are not c and i date s for surgical replacement of the aortic valve . Recently , transcatheter aortic-valve implantation ( TAVI ) has been suggested as a less invasive treatment for high-risk patients with aortic stenosis . METHODS We r and omly assigned patients with severe aortic stenosis , whom surgeons considered not to be suitable c and i date s for surgery , to st and ard therapy ( including balloon aortic valvuloplasty ) or transfemoral transcatheter implantation of a balloon-exp and able bovine pericardial valve .  The primary end point was the rate of death from any cause . RESULTS A total of 358 patients with aortic stenosis who were not considered to be suitable c and i date s for surgery underwent r and omization at 21 centers ( 17 in the United States ) . At 1 year , the rate of death from any cause ( Kaplan – Meier analysis ) was 30.7 % with TAVI , as compared with 50.7 % with st and ard therapy ( hazard ratio with TAVI , 0.55 ; 95 % confidence interval [ CI ] , 0.40 to 0.74 ; P<0.001 ) . The rate of the composite end point of death from any cause or repeat hospitalization was 42.5 % with TAVI as compared with 71.6 % with st and ard therapy ( hazard ratio , 0.46 ; 95 % CI , 0.35 to 0.59 ; P<0.001 ) . Among survivors at 1 year , the rate of cardiac symptoms ( New York Heart Association class III or IV ) was lower among patients who had undergone TAVI than among those who had received st and ard therapy ( 25.2 % vs. 58.0 % , P<0.001 ) . At 30 days , TAVI , as compared 
    Output:
    
Mechanical mitral valve replacement ( MVR ) had the lowest costs per success compared to mitral valve repair and biological MVR .