Biomedical subjects

G Langebartels

Publications and source records attributed to G Langebartels.

7 recordsLinked to original sources

PubMed2006

APOE alleles are not associated with calcific aortic stenosis.

OBJECTIVES: To analyse the association of APOE alleles with aortic stenosis (AS) in a large study population. METHODS: Patients with AS (n = 538) and a control group of the same age without heart disease (n = 536) were recruited. Left heart catheterisation was performed and mean gradient, aortic valve area, presence of stenotic coronary artery disease (CAD) and cardiovascular risk factors (hypercholesterolaemia, hypertension, smoking, diabetes mellitus and family history of CAD) were assessed. The frequency of the APOE major alleles e2, e3 and e4 was assessed by genotyping the polymorphisms APOE334 and APOE472 with a 5' exonuclease assay (TaqMan). RESULTS: Mean gradient across the aortic valve in cases was 50 (SD 20) mm Hg corresponding to a mean aortic valve area of 0.84 (SD 0.34) cm(2). 270 patients with AS had stenotic CAD. Among patients with AS, the prevalence of hypercholesterolaemia (64% v 40%, p < 0.001), smoking (43% v 27%, p < 0.001), diabetes (27% v 17%, p < 0.01), family history of CAD (30% v 21%, p </= 0.05), and male sex (65% v 44%, p < 0.001) was higher in those with than in those without CAD. The frequency of the major alleles was not different between cases and controls (APOE e2: 104 (19.3%) v 94 (17.5%); APOE e3: 319 (59.3%) v 332 (61.9%); APOE e4: 115 (21.3%) v 110 (20.5%); all p > 0.10). CONCLUSION: APOE e4 is not associated with AS, reflecting the different genetic backgrounds of CAD and AS.

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PubMed2006

Impact of pressure recovery in the evaluation of the Omnicarbon tilting disc valve.

BACKGROUND: Pressure recovery is not taken into account when calculating trans-prosthetic gradients after mechanical valve replacement using Doppler echocardiography. This may lead to underestimation of valvular performance. METHODS: Simultaneous measurement of Doppler and direct trans-prosthetic gradients was performed in a circulatory mock loop simulator with physiologic parameters at different heart rates and cardiac outputs for small-sized aortic Omnicarbon tilting disc valves (19 - 21 mm). RESULTS: In all adjustments the Doppler gradient significantly overestimated the net transvalvular gradient. The amount of pressure recovery averaged 59.3 %. CONCLUSIONS: Doppler echocardiography does not allow for pressure recovery, which is a significant phenomenon in the hemodynamic function of the Omnicarbon tilting disc valve. Valve performance is much better than expected from Doppler gradients.

Aortic Valve↗

PubMed2000

Prospectively randomized comparison of different mechanical aortic valves.

BACKGROUND: The aim of this prospectively randomized study was to evaluate the hemodynamic and functional outcomes after aortic valve replacement with 3 different bileaflet mechanical valves. METHODS AND RESULTS: Three hundred consecutive patients were randomly assigned to receive ATS (n=100), Carbomedics (n=100), or St Jude Medical Hemodynamic Plus (n=100) mechanical aortic valve replacement. There were no significant differences regarding patient age (average 61+/-8 years), body surface area (1.9+/-0.2 m(2)), left ventricular function (ejection fraction 0.59+/-0.17), and presence of aortic stenosis (90%, 89%, and 91%), respectively. All patients had postoperative as well as 6-month and 1-year follow-ups that included transthoracic echocardiography. Multivariate statistical analysis was performed. Implanted valve sizes were comparable at 24+/-2 (ATS), 23.7+/-1.6 (CM), and 23.6+/-1.9 (SJMHP) mm (NS). At 1-year follow-up, the following incidence of events was noted: death 3/1/1, all non-valve related; stroke 0/1/1; trivial transvalvular incompetence 3/3/2; paravalvular leak 2/3/2; and reoperation 0/1/1, respectively (NS). Transvalvular flow velocities were 2.5/2.6/2.4 m/s postoperatively (P:=0.03) and 2.4/2.4/2.3 m/s at 6-month follow-up, respectively (NS). There was a significant decrease in left ventricular mass for all patients but no significant differences among the groups. CONCLUSIONS: There are no clinically relevant differences among the tested bileaflet aortic valves. Regardless of valve type, there was a low complication rate. On the basis of these findings, all 3 bileaflet prostheses are well suited for aortic valve replacement.

Aortic Valve↗

PubMed2000

Comparison of On-X and SJM HP bileaflet aortic valves.

BACKGROUND AND AIM OF THE STUDY: The study aim was to evaluate the hemodynamic function after aortic valve replacement (AVR) using the On-X valve, in comparison with St. Jude Medical (SJM) HP bileaflet valves. METHODS: Patients received either the On-X (n = 20) or SJM HP prosthesis (n = 20) for AVR. The control (SJM HP) group was computer-matched with the On-X group for age, gender, aortic stenosis as underlying disease, body surface area, NYHA functional class, left ventricular size, mass and function, transvalvular pressure gradients and cardiac index. Mean implanted valve size was 23.5 mm (three 21 mm, ten 23 mm, six 25 mm, one 27 mm) in both groups. All patients underwent postoperative, and six- and 12-month follow up echocardiography. RESULTS: The intra- and postoperative course was uneventful in all patients. There were no significant differences in cross-clamp and cardiopulmonary bypass times, intensive care unit stay, in-hospital stay and postoperative NYHA functional class. Two patients (both On-X) had paravalvular leakage postoperatively and at follow up. Five patients in the control group had additional myocardial revascularization. Transvalvular flow velocities were 2.38 +/- 0.3 versus 2.38 +/- 0.4 m/s (p = NS) postoperatively, and 2.08 +/- 0.2 versus 2.22 +/- 0.3 m/s (p = NS) at one year follow up for On-X and SJM HP valves, respectively. Maximum pressure gradients were 16.9 +/- 6.0 versus 18.5 +/- 8.0 mmHg (p = NS) postoperatively and 14.0 +/- 3.7 versus 16.5 +/- 5.7 mmHg (p = NS) at one year for the two valve types, respectively. A relatively pronounced transvalvular reflux was diagnosed for On-X valves. CONCLUSION: At one year after implantation, the On-X bileaflet prosthesis is equally suited for AVR in comparison with the 'standard' therapy (SJM HP). Exact sizing requires some experience. There were no significant differences between the two prostheses with regard to hemodynamic parameters either postoperatively or at one-year follow up. Long-term prospective randomized studies yet have to be carried out.

Aortic Valve↗

PubMed1999

Prospectively randomized evaluation of stentless versus conventional biological aortic valves: impact on early regression of left ventricular hypertrophy.

BACKGROUND: The aim of this prospectively randomized study was to evaluate left ventricular hypertrophy and its regression after stentless versus conventional biological aortic valve replacement. METHODS AND RESULTS: From March 1996 through April 1998, 180 patients were prospectively selected; 106 patients received a stentless aortic valve (SAV), and 74 received a conventional stented bioprosthesis (CSB). Of these patients, 95% and 96%, respectively, had aortic stenosis. Their mean age was 72.3 and 74.8 years, and there were no significant differences in left ventricular function, preoperative pressure gradients, and NYHA functional status. Aortic annulus diameter indexes were comparable at 13.46 (SAV) versus 13.55 (CSB) mm (P=NS). Larger SAVs were implanted because of the oversizing technique. In-hospital mortality (n=3 and 1 for SAV and CSB) was not valve related. At follow-up, all patients were in NYHA class 1 or 2. Baseline end-diastolic left ventricular posterior wall thickness was 15.6 (SAV) and 14.8(CSB) mm (P=NS) and decreased to 11. 8 (SAV) and 13.2 (CSB) mm (P<0.05) at 6 months. Left ventricular mass index was 213 and 202 g/m(2) at baseline (P=NS), whereas after 6 months, it was 141 (SAV) and 170 (CSB) g/m(2) (P<0.05). CONCLUSIONS: Regression of left ventricular hypertrophy occurs in all patients after aortic valve replacement but is significantly enhanced after SAV implantation. This possibly is due to improved transvalvular hemodynamics.

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PubMed1999

Quadrileaflet stentless mitral valve replacement.

BACKGROUND: The study evaluates clinical results and hemodynamic parameters one year after implantation of a stentless quadrileaflet mitral valve (QMV). METHODS: Since August 1997 28 patients received the QMV, patient age was 69 +/- 8 years; 13 had predominant mitral stenosis and 15 incompetence, preoperative NYHA functional class was III or IV and cardiac index 1.8 +/- 0.6 L/min/m2. RESULTS: Surgery was performed using a conventional (25) or a minimally invasive approach (3). 20 patients received a medium and 8 a large-size prosthesis, crossclamp time was 58 +/- 19 min. Additional procedures were myocardial revascularization in four, tricuspid repair in two, and left-atrial radiofrequency ablation to restore sinus rhythm in six patients. Perioperative mortality (1) was not valve-related. All other patients were discharged on time. At postoperative, 6-, and 12-months follow-up mean transvalvular pressure gradients were 4.2 +/- 1.5 / 4 +/- 0.9/ 3.8 +/- 1.4 mmHg and mitral valve orifice area index was 1.5 +/- 0.3 / 1.6 +/- 0.3 / 1.6 +/- 0.4, NYHA class was I or II. CONCLUSIONS: The QMV is well suited for mitral valve replacement. The anulo-ventricular continuity is preserved and the QMV function resembles native mitral valve function. If its performance is maintained in the long term the QMV may be the mitral prosthesis of choice.

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PubMed1999

Regression of left ventricular hypertrophy after stentless versus conventional aortic valve replacement.

The goal of this study was to analyze regression of left ventricular hypertrophy after randomization to conventional biological versus stentless aortic valve replacement. Stentless (Freestyle, Toronto, n = 106) or conventional biological aortic valves (Carpentier-Edwards, n = 74) were evaluated prospectively. Preoperatively there were no differences with regard to aortic valve pathology, left ventricular function, and pressure gradients between the two patient groups. The patient annulus index (13.55 vs. 13.46 mm; NS) measured intraoperatively was used as baseline for further comparison. Postoperatively, left ventricular mass index was 213+/-77 g/m2 (stentless) compared with 202+/-72 (conventional group) g/m2 (NS), whereas after 6 months it was 141+/-41 g/m2 in the stentless and 170+/-43 g/m2 in the conventional group (P<.05). Regression of left ventricular hypertrophy occurs in all patients after aortic valve replacement. Nevertheless, the use of stentless bioprostheses leads to a significant enhancement, which may result in a reduction of the cardiac risk profile for the patient.

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