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Transcatheter aortic valve implantation/replacement

Subclinical leaflet thrombosis in surgical and transcatheter bioprosthetic aortic valves: an observational study

20 Sep, 17 | by lfountain

Use of transcatheter aortic valve replacement (TAVR) for severe aortic stenosis (AS) has grown rapidly over the last decade and the technology has correspondingly matured. Nevertheless, recent data suggest that subclinical thrombosis may form on some leaflets of the TAVR prostheses following implant. The frequency, implications, and required treatment of this process are largely unknown, as is the relevance to surgical aortic valve replacement (SAVR).


Surgical or Transcatheter Aortic-Valve Replacement in Intermediate-Risk Patients (SURTAVI Investigators)

24 May, 17 | by flee

Transcatheter aortic valve replacement (TAVR) is superior to medical therapy in inoperable patients with severe, symptomatic aortic stenosis (AS), and may be the preferred option in high-risk surgical patients. The comparative efficacy of TAVR and surgical aortic valve replacement (SAVR) in intermediate risk AS patients has been less well studied. The PARTNER 2 randomized trial showed non-inferiority of balloon expandable TAVR compared to SAVR in intermediate risk patients at 2 years. In the Surgical Replacement and Transcatheter Aortic Valve Implantation (SURTAVI) trial, a self-expandable TAVR prosthesis (Medtronic’s CoreValve [84%] and Evolut R [16%]) was randomized against SAVR in 1660 intermediate risk patients. The primary endpoint was a composite of death from any cause and disabling stroke at 24 months. The mean age was 79.8±6.2 years with an average Society of Thoracic Surgeons (STS) estimated risk of death of 4.5±1.6%. At 24 months, the TAVR group was non-inferior to the SAVR group for the primary endpoint (12.6% vs. 14.0%, posterior probability of non-inferiority, >0.999). Rates of both individual components of this endpoint were also similar. TAVR, compared to surgery was associated with lower rates of acute kidney injury (1.7% vs. 4.4%), atrial fibrillation (12.9% vs. 43.4%), and transfusion requirements (12.5% vs. 41.1%), but higher rates of residual aortic regurgitation (5.3% vs. 0.6%) and need for pacemaker implantation (25.9% vs. 6.6%).


Von Willebrand Factor Multimers during Transcatheter Aortic-Valve Replacement

20 Sep, 16 | by flee

Patients with stenotic or regurgitant aortic valve disease appear to cleave multimers of Von Willebrand factor (HMW-multimer), presumably due to high-shear stresses and non-laminar flow. Van Belle and colleagues hypothesized that transcatheter aortic valve replacement (TAVR) would correct this process, but that significant residual paravalvular leak (PVL) following TAVR would abrogate this corrective effect. Moderate to severe PVL has been associated with increased rates of hospitalization, and death compared to mild PVL. Thus, immediate characterization of the degree of PVL post TAVR using echocardiographic, hemodynamic and/or angiographic data is important, though occasionally challenging, particularly if discrepant. In this study, ratios of HMW-multimers and platelet reactivity (CT-ADP) were assessed pre- and post-TAVR in 183 patients receiving the Sapien XT valve at a single center. Among the 137 patients with no regurgitation following TAVR, HMW-multimer ratios and CT-ADP values changed significantly within 15 minutes of the TAVR using point of care testing. Among those with significant PVL, these assays only changed following effective correction of the PVL. These results were unaffected by concomitant use of clopidogrel or pre-existing mitral regurgitation. Using TEE as a reference standard, ROC curves identified a CT-ADP result of ≥180 seconds (AUC = 0.93) and HMW-multimer ratio of ≤ 0.8 (AUC = 0.94) as providing optimal discrimination for significant PVL. In multivariate models, an HMW-ratio < 0.8 or CT-ADP value > 180 seconds at the end of the procedure were both significantly associated with ≥3-fold higher one-year mortality rates.


Transcatheter aortic valve implantation in intermediate risk patients

17 Jun, 16 | by flee

Transcatheter aortic valve implantation (TAVI) has had a major impact on both morbidity and mortality in high-risk and inoperable patients with severe aortic stenosis. Robust evidence has supported widespread adoption in this patient group but uncertainty exists as to whether TAVI may also achieve clinical equipoise with surgical aortic valve replacement (AVR)  in lower risk groups.  In the industry sponsored PARTNER 2 trial, patients deemed at intermediate surgical risk (generally with an STS score between 4 and 8) were randomized to either TAVI with the SAPIEN XT valve or conventional surgery (bioprosthetic valve of operative choice).  In a study powered for non-inferiority, a total of 2032 patients at 57 North American centers were recruited with a primary end-point of all cause mortality and disabling stroke measured at 24 months.  TAVI was found to be none-inferior to surgical AVR at 2 years with respective event rates of 19.3% and 21.1% (HR, 0.89; 95% CI, 0.73 to 1.09; P=0.25). The rates of stroke (6%) and death (17-18%) were very similar between groups. When analyzing only those patients whom underwent TAVI via transfemoral access (76% of the total population), there was a signal that TAVI resulted in a lower incidence of the primary end-point of death or stroke (P=0.05). The non-transfermoral (alternative) access cohort had similar outcomes to the surgical AVR group.  TAVI patients were found to have a lower incidence of major bleeding, kidney failure and new onset atrial fibrillation as well as having larger aortic valve areas.  In the surgical AVR group patients had less paravalvular leak and fewer vascular complications.  Interestingly, the rate of permanent pacemaker implantation was similar between the two groups at less than 10% (P=0.17)


In this landmark study, patients with intermediate surgical risk had similar, and in some instances, superior outcomes with TAVI as compared to conventional surgical AVR.  As with PCI before it, the rise of minimally invasive valve replacement appears inexorable and is likely to change the landscape of cardiac intervention over the coming years as both technology and operator experience improves.  In fact, these data reflect a TAVI technology that has already been supplanted in clinical practice by a next generation technology in most countries.


Leon MB, Smith CR, Mack MJ, Makkar RR, Svensson LG, Kodali SK, Thourani VH, Tuzcu EM, Miller DC, Herrmann HC, Doshi D, Cohen DJ, Pichard AD, Kapadia S, Dewey T, Babaliaros V, Szeto WY, Williams MR, Kereiakes D, Zajarias A, Greason KL, Whisenant BK, Hodson RW, Moses JW, Trento A, Brown DL, Fearon WF, Pibarot P, Hahn RT, Jaber WA, Anderson WN, Alu MC, Webb JG; PARTNER 2 Investigators. Transcatheter or Surgical Aortic-Valve Replacement in Intermediate-Risk Patients. N Engl J Med. 2016 374(17)1609-20


Summarized by  James McCabe, MD

TAVR adoption and outcomes in German national practice

29 Feb, 16 | by flee

The advent of transcatheter aortic valve replacement (TAVR) has afforded an alternative to surgical aortic valve replacement (SAVR) for high-risk or non-operative candidates for aortic valve surgery.  However, the adoption of TAVR may not be limited to the patient population for who the procedure has studied and outcomes in routine clinical practice may not reflect those of prior randomized trials. In this retrospective study including data on all TAVR and SAVR procedures in Germany from 2007 to 2013, the authors examine the use of these procedures in clinical practice and associated patient outcomes.  A total of 32,581 TAVI and 55,992 SAVR (without concomitant revascularization) were performed during this period.  Use of TAVR increased from 144 procedures in 2007 to 9147 in 2013, while the number of SAVRs decreased from 8622 to 7048 over the same period.  Compared with patients receiving SAVR, patients receiving TAVR were older (81.0±6.1. years vs 70.2±10.0 years) and higher risk as assessed by logistic EuroScore (22.4% vs 6.3%).  Over the period of study, in-hospital mortality following TAVR decreased from 13.2% to 5.4%.  Concurrently, in-hospital mortality following SAVR declined from 3.8% to 2.2%.  Importantly, the risk-score for patients undergoing TAVR increased over time, suggesting improvements in mortality were not a result of increasing use of TAVR in a lower risk population.  Complications of permanent pacemaker implantation were higher following TAVR (17.7% vs. 4.0%, P<0.001) as were rates of stroke (2.5% vs. 1.8%, P<0.001), and acute kidney injury (5.5% vs. 3.0%, P<0.001) while bleeding events were less frequent following TAVR (8.2% vs. 14.0%,  P<0.001).


In a nationwide evaluation of TAVR and SAVR performed in Germany between 2007 and 2013, there was a large increase in the use of TAVR that did not appear related to expanded use in lower risk patients.  Furthermore, outcomes of both TAVR and SAVR improved during this period.  These findings are consistent with a learning curve in the use of TAVR and highlight the importance of continued evaluation of the use and outcomes of this procedure in routine practice to ensure optimal patient care.

Summarized by Hussain Contractor and Steven M. Bradley

Reinöhl J, Kaier K, Reinecke H, Schmoor C, Frankenstein L, Vach W, Cribier A, Beyersdorf F, Bode C and Zehender M. Effect of Availability of Transcatheter Aortic-Valve Replacement on Clinical Practice. N Engl J Med. 2015 Dec 17;373(25):2438-47.

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