Transapical aortic valve implantation off-pump in patients with impaired left ventricular function

Myocardial injury associated with transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation (TAVI) has emerged as an important treatment option for elderly patients with symptomatic aortic stenosis whose risk is too high or prohibitive for conventional surgery. Despite notable progress during the past decade, continuous efforts directed at further improvement of procedural safety and performance are required, especially considering expanding indications for interventional treatment options among lower-risk populations. One issue that needs to be addressed is myocardial damage, which can frequently be observed after TAVI and has been linked to worse prognosis. Yet, knowledge concerning the underlying mechanisms and clinical impact remains scarce, and further investigation in this field is warranted. In this review, we provide a contemporary summary of the types of myocardial injury associated with TAVI, including access-related injury, mechanical trauma and ischemia, the role of myocardial biomarkers, and the impact on left ventricular function, with emphasis on potential mechanisms and clinical implications.

A critical review of hemodynamic changes and left ventricular remodeling after surgical aortic valve replacement and percutaneous aortic valve replacement

The introduction of transcatheter aortic valve replacement (TAVR) in clinical practice has widened options for symptomatic patients at high surgical risk; however, it is not known whether TAVR has equivalent or prolonged benefits in terms of left ventricular (LV) remodeling.

METHODS

To explore the relative hemodynamic benefits and postoperative LV remodeling associated with TAVR and surgical aortic valve replacement (SAVR), we performed a critical review of the available literature. A total of 67 studies were included in this systematic review.

RESULTS

There is at least equivalent if not slightly superior hemodynamic performance of TAVR over SAVR, and TAVR showed lower prosthesis-patient mismatch compared with SAVR. However, LV mass appears to regress to a greater degree after SAVR compared with TAVR. Aortic regurgitation, paravalvular in particular, is more common after TAVR than SAVR, although it is rarely more than moderate in severity. Improvements in diastolic function and mitral regurgitation are reported in only a handful of studies each and could not be compared across prosthesis types.

CONCLUSIONS

The published data support the hemodynamic comparability of SAVR and TAVR, with the higher incidence of prosthesis-patient mismatch in SAVR offset by higher incidence of paravalvular leak in TAVR. These results highlight the need for further studies focusing on hemodynamic changes after valve therapy.

Clinical presentation and outcomes after transcatheter aortic valve implantation in patients with low flow/low gradient severe aortic stenosis

OBJECTIVES

To identify predictors of mortality, functional status, and hemodynamical changes of patients undergoing transcatheter aortic valve implantation (TAVI) for low flow/low gradient aortic stenosis (LF/LG AS).

BACKGROUND

There is little published data regarding the outcomes of patients with LF/LG AS following TAVI.

METHODS

Sixty-eight patients with severe AS, left ventricular dysfunction (ejection fraction [EF] <35%) and low flow (LF) AS underwent TAVI. Patients were stratified according to the aortic mean pressure gradient (low gradient [LG]; with Pmean ≤40 mm Hg and high gradient [HG]: Pmean >40 mm Hg). The baseline parameters and clinical outcomes were subsequently compared among the two groups. Cox proportional hazards were used to identify predictors of 6-month mortality.

RESULTS

There were 38 patients in the LG group and 30 patients in the HG group. There were no significant difference in 30-day mortality between the two groups. The 6-month and 1-year mortality, however, was 3.8-fold and 2.8-fold higher in the LG group than in the HG group (37.8% vs. 10.3%, P = 0.01 and 37.8% vs. 13.3%, respectively, P = 0.01). Univariable predictors for 6-month mortality were: STS Score, aortic valve area, and aortic mean pressure gradient. However, only STS Score (HR 1.08, 1.04-1.12, P < 0.001) remained as independent predictor in the multivariable analysis. Six months after TAVI, hemodynamical (EF > 50%) and clinical (NYHA class I) improvements were shown in both HG and LG groups.

CONCLUSIONS

LF/LG AS does not influence procedural mortality after TAVI but exhibits a strong impact on 6-month and 1-year mortality. The survivors, however, exhibit considerable hemodynamical and clinical improvements. Therefore, risk stratification and TAVI benefit should be weighted in every patient with LF/LG AS.

Transcatheter aortic valve replacement in patients with severe aortic stenosis who are at high risk for surgical complications: summary assessment of the California Technology Assessment Forum

BACKGROUND

The California Technology Assessment Forum is dedicated to assessment and public reporting of syntheses of available data on medical technologies. In this assessment, transcatheter aortic valve replacement (TAVR) was evaluated for patients with severe aortic stenosis (AS) who are at high risk for complications.

METHODS AND RESULTS

In this assessment, 5 criteria were used: Regulatory approval, sufficient scientific evidence to allow conclusions on effectiveness, evidence that the technology improves net health outcomes, evidence that the technology is as beneficial as established methods, and availability of the technology outside investigational settings. In this assessment, all 5 criteria were judged to have been met. The primary benefit of TAVR is the ability to treat AS in patients who would otherwise be ineligible for surgical aortic valve replacement. It may also be useful for patients at high surgical risk by potentially reducing periprocedural complications and avoiding the morbidity and recovery from undergoing heart surgery. Potential harms include the need for conversion to an open procedure, perioperative death, myocardial infarction, stroke, bleeding, valve embolization, aortic regurgitation, heart block that requires a permanent pacemaker, renal failure, pulmonary failure, and major vascular complications such as cardiac perforation or arterial dissection. Potential long-term harms include death, stroke, valve failure or clotting, and endocarditis. As highlighted at the February 2012 California Technology Assessment Forum meeting, the dispersion of this technology to new centers across the United States must proceed with careful thought given to training and proctoring multidisciplinary teams to become new centers of excellence.

CONCLUSIONS

TAVR is a potentially lifesaving procedure that may improve quality of life for patients at high risk for surgical AVR. However, attention needs to be paid to appropriate patient selection, their preoperative evaluation, surgical techniques, and postoperative care to preserve and improve on the results attained in the Placement of Aortic Transcatheter Valve trial. Specialty societies are collaborating to ensure that this happens in a rational and comprehensive manner.

A systematic review of transapical aortic valve implantation

BACKGROUND

Transcatheter aortic valve implantation (TAVI) through a transapical approach (TAAVI) for severe aortic stenosis becomes the procedure of choice in cases where patients have peripheral artery disease and unfeasible access due to excessive atherosclerotic disease of the iliofemoral vessels and aorta. The present systematic review aimed to assess the safety, success rate, clinical outcomes, hemodynamic outcomes, and survival benefits of TAAVI.

METHODS

Electronic searches were performed in 6 databases from January 2000 to February 2012. The primary end points included feasibility and safety. Other end points included echocardiographic findings, functional class improvement, and survival.

RESULTS

After applying the inclusion and exclusion criteria, 48 out of 154 shortlisted potentially relevant articles were selected for assessment. Of these, 26 studies from 24 centers including total number of 2,807 patients were included for appraisal and data extraction. The current evidence on TAAVI for aortic stenosis is limited to observational studies. Successful TAAVI implantation occurred in >90% of patients. On average, the procedure took between 64 to 154 minutes to complete. The incidence of major adverse events included 30-day mortality (4.7-20.8%); cerebrovascular accident (0-16.3%); major tachyarrhythmia (0-48.8%); bradyarrhythmia requiring permanent pacemaker insertion (0-18.7%); cardiac tamponade (0-11%); major bleeding (1-17%); myocardial infarction (0-6%); aortic dissection/rupture (0-5%); moderate to severe paravalvular leak (0.7-24%); cardiopulmonary bypass support (0-15%); conversion to surgery (0-9.5%); and valve-in-valve implantation (0.6-8%). Mean aortic valve area improved from 0.4-0.7 cm(2) before TAAVI to 1.4-2.1 cm(2) after TAAVI. The peak pressure gradient across the aortic valve decreased from >70 mmHg to <20 mmHg after TAAVI. One-year survival ranged from 49.3% to 82% and the 3-year survival was 58% in 2 series.

CONCLUSIONS

TAAVI appears to be feasible with a reasonable safety and efficacy portfolio. Randomised controlled trials are required to compare transapical vs. transfemoral TAVI when both techniques are equally feasible.

The year in review: the surgical treatment of valvular disease-2011

This review highlights important advances in techniques, guidelines, outcomes and innovations in valve surgery during 2011.