***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 The use of transcatheter aortic-valve replacement has been shown to reduce mortality among high-risk patients with aortic stenosis who are not c and i date s for surgical replacement . However , the two procedures have not been compared in a r and omized trial involving high-risk patients who are still c and i date s for surgical replacement . METHODS At 25 centers , we r and omly assigned 699 high-risk patients with severe aortic stenosis to undergo either transcatheter aortic-valve replacement with a balloon-exp and able bovine pericardial valve ( either a transfemoral or a transapical approach )  or surgical replacement .  The primary end point was death from any cause at 1 year . The primary hypothesis was that transcatheter replacement is not inferior to surgical replacement . RESULTS The rates of death from any cause were 3.4 % in the transcatheter group and 6.5 % in the surgical group at 30 days ( P=0.07 ) and 24.2 % and 26.8 % , respectively , at 1 year ( P=0.44 ) , a reduction of 2.6 percentage points in the transcatheter group ( upper limit of the 95 % confidence interval , 3.0 percentage points ; predefined margin , 7.5 percentage points ; P=0.001 for noninferiority ) . The rates of major stroke were 3.8 % in the transcatheter group and 2.1 % in the surgical group at 30 days ( P=0.20 ) and 5.1 % and 2.4 % , respectively , at 1 year ( P=0.07 ) . At 30 days , major vascular complications were significantly more frequent with transcatheter replacement ( 11.0 % vs. 3.2 % , P<0.001 ) ; adverse events that were more frequent after surgical replacement included major bleeding ( 9.3 % vs. 19.5 % , P<0.001 ) and new-onset atrial fibrillation ( 8.6 % vs. 16.0 % , P=0.006 ) . More patients undergoing transcatheter replacement had an improvement in symptoms at 30 days , but by 1 year , there was not a significant between-group difference . CONCLUSIONS In high-risk patients with severe aortic stenosis , transcatheter and surgical procedures for aortic-valve replacement were associated with similar rates of survival at 1 year , although there were important differences in periprocedural risks . ( Funded by Edwards Lifesciences ; Clinical Trials.gov number , NCT00530894 . ) In the last decade , transcatheter aortic valve implantation ( TAVI ) , a disruptive technology , has revolutionized the therapy of symptomatic severe aortic stenosis , and current guidelines state that the recommendations for TAVI and surgical aortic valve replacement ( SAVR ) are equivalent in patients at high-risk . Increased operator experience , technical advances in the new generation of transcatheter heart valves ( THV ) and excellent TAVI results in recently published r and omized controlled trials have led to the expansion of TAVI indication as an alternative to SAVR in intermediate-risk subjects , given appropriate patient selection . The time is opportune to examine the role of TAVI in low-risk patients , currently the objective of on-going r and omized trials . This review aims to summarize the available knowledge on TAVI in low- to intermediate-risk patients and to discuss the potential advantages and pitfalls TAVI will face in this clinical setting 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 prospect i ve 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 Background and Purpose : Transcatheter aortic valve implantation ( TAVI ) is a rapidly emerging treatment option for patients with aortic valve stenosis and high surgical risk . Different access routes have been proposed for TAVI including transapical , transsubclavian and transfemoral , with percutaneous transfemoral being the preferred because least invasive and nonsurgical . However , vascular access site complications due to the large-bore delivery catheters remain an important clinical issue , particularly with respect to the elderly patient collective typically considered for TAVI .  In the study , the authors analyzed their 4-year TAVI experience with respect to vascular complications and their management in patients undergoing completely percutaneous transfemoral TAVI procedures . Patients and Methods : Since 2006 , TAVI was performed in 101 consecutive patients at the West German Heart Center Essen . 33 patients underwent transapical TAVI , eight patients transfemoral TAVI with surgical access or closure , and 60 patients percutaneous transfemoral TAVI using two commercially available prosthetic valve devices . Results : Completely percutaneous TAVI was technically successful in all but one patient with malpositioning in the aortic arch during valve retrieval . There was no intraprocedural death and 30-day mortality was 12 % ( 7/60 ) . Vascular access site complications occurred in 19 patients ( 32 % ) , necessitating surgical repair in six of them ( 10 % ) . Complications included retroperitoneal hematoma ( n = 2 ) , iliac or femoral artery dissection ( n = 10 ) , (pseudo)aneurysm formation ( n = 3 ) , and closure device-induced vessel stenosis/ occlusion ( n = 6 ) . Of these , 13 cases could be managed either conservatively ( n = 5 ) or by contralateral endovascular treatment ( n = 8) . Conclusion : Completely percutaneous TAVI has a high acute success rate with low intraprocedural and 30-day mortality . The patient collective appears to be prone to vascular complications which remain an important limitation of this novel technique . Although conservative or endovascular management is possible in the majority of cases , further technological developments are obliged to reduce the vascular complication rate . ZusammenfassungHintergrund und Fragestellung : Die katheterbasierte Aortenklappenimplantation ist eine neue , in der klinischen Routine bereits breit angew and te Therapieoption für Hochrisikopatienten mit kalzifizierter Aortenklappenstenose . Während in der Anfangsphase noch eine chirurgische Freilegung der arteriellen Zugangsgefäße und damit verbunden eine Vollnarkose nötig waren , ist die Durchführung heute in einer rein perkutanen Technik und somit sogar unter Analgosedierung möglich . Aufgrund der großen Kaliber der zur Einführung und zum Vorschieben der Prothese benötigten Schleusen und Katheter birgt diese Prozedur jedoch das Risiko einer Verletzung der arteriellen Zugangsgefäße , insbesondere da diese bei den betroffenen , älteren Patienten häufig atherosklerotische Veränderungen aufweisen . Die vorliegende Untersuchung gibt einen Überblick über die vaskulären Komplikationen und mögliche Managementstrategien an einem Kollektiv von 60 konsekutiven Patienten , bei denen in rein perkutaner Technik eine transfemorale Aortenklappenimplantation durchgeführt wurde . Patienten und Method ik : Seit 2006 wurde am Westdeutschen Herzzentrum Essen bei insgesamt 101 konsekutiven Patienten eine kathetergesteuerte Aortenklappenimplantation durchgeführt , bei 33 Patienten über den transapikalen , bei 68 Patienten über den transfemoralen Zugang . Während bei den initialen acht in transfemoraler Technik beh and elten Patienten noch eine chirurgische Freilegung und/oder ein chirurgischer Verschluss der Zugangsgefäße durchgeführt wurde , erfolgte die Implantation der ballonexp and ierbaren Edwards-Sapien- ( n = 41 ) und der selbstexp and ierbaren CoreValve-Prothese ( n = 19 ) bei de hemofolgenden 60 Patienten in rein perkutaner Technik unter Verwendung von Nahtverschlusssystemen . Ergebnisse : Bis auf eine Fehlpositionierung i m Aortenbogen konnten alle  Aortenklappenprothesen  erfolgreich in rein perkutaner Technik und ohne intraprozeduralen Todesfall implantiert werden . Die 30-Tage-Mortalität betrug 12 % . Postinterventionell zeigte sich eine signifikante Verbesserung der Hämodynamik mit Abfall des mittleren transaortalen Druckgradienten von 52 ± 18 auf 13 ± 6 mmHg und einer Zunahme der Klappenöffnungsfläche von 0,6 ± 0,2 auf 1,5 ± 0,3 cm2 . Die Rate an vaskulären Komplikationen betrug 32 % ( 19 von 60 Patienten ) . Die Komplikationen beinhalteten zwei retroperitoneale Hämatome , zehn Dissektionen der Femoral- und Iliakal gefäße , drei Aneurysmabildungen und sechs ver schluss systeminduzierte Komplikationen . In fünf Fällen erfolgte eine konservative Therapie , bei acht Patienten konnte eine katheterinterventionelle Beh and lung durchgeführt werden . Eine operative Sanierung war bei sechs Patienten ( 10 % ) nötig . Schlussfolgerung : Die transfemorale Aortenklappenimplantation kann heutzutage in rein perkutaner Technik mit einer hohen Erfolgsrate , geringer Mortalität und guten hämodynamischen und klinischen Ergebnissen durchgeführt werden . Vaskuläre Komplikationen sind jedoch noch häufig und stellen eine wichtige Limitation dieser neuen Technik dar . Obwohl ein konservatives oder interventionelles Management dieser Komplikationen in der Regel möglich ist , müssen zukünftige Weiterentwicklungen in besonderem Maße auch auf eine Reduktion der vaskulären Komplikationsrate gerichtet sein OBJECTIVE A population -based point-prevalence study was conducted to determine the prevalence of peripheral arterial disease ( PAD ) in Sweden , with special attention to critical limb ischemia and sex differences . METHODS An age-st and ardized r and omly selected population sample of 8000 women and men , aged 60 to 90 years , from four different regions in Sweden was invited to participate . The sample had the same age and gender distribution as the Swedish population in this age group . Participating subjects completed question naires on medical history , present medication , and symptoms , and their ankle-brachial index ( ABI ) was measured . Subjects were analyzed for presence of PAD according to reported symptoms and an ABI<0.9 . RESULTS A total of 5080 subjects were included , giving a participation rate of 64 % . The prevalence of any PAD , asymptomatic PAD , intermittent claudication , and severe limb ischemia was , respectively , 18 % ( 95 % confidence interval [ CI ] , 16 % to 20 % ) 11 % ( 9 % to 13 % ) , 7 % ( 6.5 to 7 % ) and 1.2 % ( 1 % to 1.5 % ) . Women had a higher prevalence than men when PAD was diagnosed with ABI only ; that is , asymptomatic PAD ( 12.6 % vs 9.4 % , P=.03 ) and severe limb ischemia ( 1.5 % vs 0.8 % , P<.008 ) . The prevalence of any PAD was 7.9 % in the age group 60 to 65 years and increased to 47.2 % among the age group 85 to 90 years . Severe limb ischemia occurred in 0.3 % in the youngest age group , was highest in the age group 80 to 84 years at 3.3 % , and declined to 2.5 % among the oldest . The prevalence of P 
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Moreover , the adoption of smaller sheaths during TAVI procedures was associated with fewer VC both in PAD and non-PAD patients , but the latter group had a more pronounced benefit .
CONCLUSIONS Patients with pre-existent PAD are at increased risk of all-cause mortality and VC after TAVI .
The adoption of smaller sheaths during the procedure seems to be associated with fewer peri-procedural VC both in PAD and non-PAD patients