New echocardiographic screening tool for left ventricular tract obstruction risk assessment in TMVR.

BACKGROUND: Transcatheter mitral valve replacement (TMVR) is an alternative to conventional surgery to treat severe mitral disease but its use is limited by the risk of left ventricular outflow tract obstruction (LVOTO). Screening depends on ECG-gated computed tomography (CT) that is not widely available and requires contrast. We developed and validated a transthoracic echocardiographic (TTE) method to assess the risk of LVOTO after TMVR with the Tendyne System. METHODS: We measured the LVOT longitudinal area on preoperative TTE dataset of patients screened for TMVR. The LVOT was measured as the box-area included by the aortic valve annulus, the anterior mitral leaflet (AML), the c-septum distance line, and the respective length of the AML on the interventricular septum. We analyzed the correlation between the TTE LVOT-box and the CT-measured neoLVOT area. Prediction performance for eligible patients was tested with ROC curves. RESULTS: Thirty-nine patients were screened, out of 14 patients (36%) not eligible for TMVR, 8 had risk of LVOTO. We found a linear correlation between the TTE LVOT-box and the CT-measured Neo-LVOT (r = 0.6, p = 0.002). ROC curve showed that the method is specific and sensitive and the cut-off value of the measure LVOT-box is 350 mm2. CONCLUSIONS: The proposed method is reliable to evaluate the risk of LVOTO after TMR with the Tendyne System. It is quick and easy and can be used as a first-line assessment in the outpatient clinic. Patients with LVOT-box <350 mm2 should not be further screened with ECG-gated cardiac CT.

Flow dynamic assessment of native mitral valve, mitral valve repair and mitral valve replacement using vector flow mapping intracardiac flow dynamic in mitral valve regurgitation.

Objectives: The present study aims to assess and describe the intracardiac blood flow dynamic in patients with mitral regurgitation (MR), repaired mitral valves (MV) and mitral valve prostheses using vector flow mapping (VFM). Methods: Patients with different MV pathologies and MV disease treatments were analysed. All patients underwent 2D transthoracic echocardiography, and images for flow visualization were acquired in VFM mode in an apical three-chamber view and four-chamber view. Vectors and vortices were qualitatively analyzed. Results: thirty-two (32) patients underwent 2D transthoracic echocardiography (TTE) with VFM analysis. We evaluated intracardiac flow dynamics in 3 healthy subjects, 10 patients with MR (5 degenerative, 5 functional), 4 patients who underwent MV repair, 5 who underwent MV replacement (3 biological, 2 mechanical), 2 surgically implanted transcatheter heart valve (THV), 2 transcatheter edge-to-edge MV repair with MitraClip (TEER), 3 transcatheter MV replacement (TMVR) and 3 transapical off-pump MV repair with NeoChord implantation. Blood flow patterns are significantly altered in patients with MV disease and MV repair compared to control patients. MV repair is superior to replacement in restoring more physiologicalpatterns, while TMVR reproducesan intraventricular flowcloser to normal than surgical MVR and TEER. Conclusions: Intracardiac flow patterns can be clearly defined using VFM. Restoration of a physiological blood flow pattern inside the LV directly depends on the procedure used to address MV disease.

In vitro assessment of pacing as therapy for aortic regurgitation.

Background and objective: Clinical evaluation of pacing therapy in mitigating the aortic insufficiency after transchateter aortic valve implantation often gives contradictory outcomes. This study presents an in vitro investigation aimed at clarifying the effect of pacing on paravalvular leakage. Methods: A series of in vitro tests reproducing the heart operating changes clinically obtained by pacing was carried out in a 26 mm Edwards Sapien XT prosthesis with mild paravalvular leakage. The effect of pacing on the regurgitant volumes per cycle and per minute was quantified, and the energy and power consumed by the left ventricle were calculated. Results: Results indicate that though pacing results in some reduction in the total regurgitation per cycle, the volume of fluid regurgitating per minute increases substantially, causing overload of left ventricle. Conclusions: Our tests indicate no effective haemodynamic benefit from pacing, suggesting a prudential clinical use of this therapy for the treatment of postoperative aortic regurgitation.

Early switch from vancomycin to oral linezolid for treatment of gram-positive heart valve endocarditis.

BACKGROUND: Patients with complicated gram-positive endocarditis are usually treated with a combination of surgical procedure and long-term antibiotic therapy with intravenous vancomycin. However, oral linezolid offers the potential for an early switch from intravenous vancomycin to oral linezolid therapy. METHODS: We conducted a retrospective study from February 2002 to August 2005 to determine the potential for early switch from intravenous vancomycin to oral linezolid in patients surgically treated for a left-sided active gram-positive endocarditis. RESULTS: Fourteen patients were identified; average age was 52 +/- 16 years. There were 10 (85%) and 2 (15%) cases of native and prosthetic valve endocarditis, respectively. Patients were operated on 3 to 10 days after diagnosis. There were no cases of operative mortality. Mean follow-up was 20.8 +/- 7.0 months. Two (14%) patients died of noncardiac causes during follow-up. The mean intensive care unit length of stay was 3.1 +/- 2.3 days, and mean hospital length of stay was 10.5 +/- 3.4 days. No cases of recurrent endocarditis or periprosthetic leakage were observed. CONCLUSIONS: The combination of aggressive surgical treatment and the early switch from intravenous vancomycin to oral linezolid for treatment of active gram-positive heart valve endocarditis is safe and effective, and reduces infection relapses, vancomycin use, hospital length of stay, and economic costs.