Biomedical subjects

Sven Lehmann

Publications and source records attributed to Sven Lehmann.

10 recordsLinked to original sources

PubMed2006

Replacing cardiopulmonary bypass with extracorporeal membrane oxygenation in lung transplantation operations.

OBJECTIVE: Cardiopulmonary bypass (CPB) support is required in some lung transplantation (LTX) operations. CPB support and full-dose heparin increases the risks of bleeding and early graft dysfunction. We report our experiences of replacing CPB with heparin-bonded low-dose heparin extracorporeal membrane oxygenation (ECMO) support in LTX surgery. METHODS: From 2003 to 2005 forty-seven patients were transplanted. Thirty-seven LTX patients were retrospectively evaluated for this study (10 patients were excluded due to heart-lung-, lung-kidney transplantation, LTX with bypass grafting, and ASD closure or emergency CPB support). Extracorporeal circulation support was necessary in 40% of the 37 LTX patients due to severe primary or secondary pulmonary hypertension (P or SPHTN), right heart dysfunction, or hemodynamic instability. There were seven LTX procedures with CPB and eight implantations with ECMO support. CPB (high-dose heparin) and ECMO support (ACT 160-220 s) was always set up through femoral veno-arterial canulation. All patients had limited access thoracotomies without transsection of the sternum. Normothermia was maintained in all patients. CPB patients: PPH 15%, COPD 15%, IPF with mean PAP>40 mmHg 70%. ECMO patients: PPH 13%, COPD 13%, IPF with severe PAP pressure elevation 74%. RESULTS: In patients undergoing LTX for PPH, the ECMO support was directly extended into the post-operative period. Packed red blood cell (PRBC) transfusion requirements during the operation and the first 24h were 13.25+/-1.6 PRBC units versus 5.1+/-2.8 PRBC units on CBP (p=0.02). Operative time was longer (p=0.11) in the ECMO LTX (451 min+/-76 vs 346+/-140). The increased 90-day mortality rate of the ECMO patients showed a trend toward significance (p=0.056), which was related to infectious complications (3 vs 1 patient). Severe graft ischemia/reperfusion injury occurred in 9% in the CPB versus 13% in the ECMO group. The 1-year survival was significantly reduced in ECMO patients (p=0.004, log-rank test). CONCLUSIONS: The advantages of femoral canulation rather than conventional central connections in lung transplantation procedures led to an undisturbed operative field. A significantly higher blood product amount was required in ECMO patients, which might lead to increased infection and mortality rates. CPB, obviously, should remain the standard support technique if extracorporeal circulation is required in lung transplantation surgery.

Adult↗

PubMed2006

Patient prosthesis mismatch affects short- and long-term outcomes after aortic valve replacement.

OBJECTIVE: The aim of this study was to evaluate the impact of patient prosthesis mismatch (PPM) and additional risk factors on outcome after aortic valve replacement (AVR). METHODS: Four thousand one hundred and thirty-one patients who were operated between May 1996 and April 2004 were evaluated. One thousand eight hundred and fifty-six patients received bileaflet mechanical AVR and 2275 stented xenograft AVR. PPM was defined as severe if manufacturers effective orifice area (EOA) divided by body surface area (BSA) was <0.65 cm(2)/m(2) and as moderate in the range of 0.65-0.85 cm(2)/m(2). PPM, age, gender, EOA index, emergency indication for surgery (within 24h), EuroSCORE as well as requirement for additional procedures were tested. Univariate (Fisher's exact test) and multivariate logistic regression analysis as well as survival analysis (Kaplan-Meier) were performed. RESULTS: Severe PPM was present in 97 (2.4%) and moderate PPM in 1103 (26.7%) patients. PPM occurs more frequently with xenograft AVR. In-hospital mortality was 5.2% for severe, 10.6% for moderate and 6.9% with no PPM (p=0.018, OR 1.4). Moderate PPM was independently predictive for short- and long-term mortality. Further analysis revealed patient age >70 years (n=1589, p=0.002, OR 1.85), emergency indication (n=374, p<0.001, OR 4.4), EuroSCORE >10 (n=494, p<0.001, OR 4.7) and additional cardiac procedures (n=2049, p<0.001, OR 2.0) as predictors for adverse outcome after AVR. CONCLUSION: Severe PPM is rare; moderate PPM is present in a quarter of patients. PPM has a significant impact on short- and long-term mortality after AVR.

Aged↗

PubMed2005

Clinical experience with stentless mitral valve replacement.

BACKGROUND: Our aim is to describe the clinical experience with stentless mitral valve (SMV) replacement with special focus on the functionality of the SMV. METHODS: Fifty-two patients (68 +/- 8.5 years old; 36 female) have been prospectively evaluated since August 1997. The chordally supported SMV (Quattro) was implanted for mitral stenosis (n = 26), severe incompetence (n = 17), or mixed lesion (n = 9). Preoperative New York Heart Association class was 3.1 +/- 0.6. Twenty patients received additional intraoperative ablation therapy. Mean follow-up is 37.3 +/- 18.7 months (range, 1 to 65). RESULTS: Surgery was performed using conventional sternotomy (33) or anterolateral minithoracotomy (19). Atrial rhythm was reestablished in 17 of 20 patients. Six patients operated on early in this series required reoperation, 2 for paravalvular leakage, 2 for functional stenosis, 1 with pannus formation due to underlying rheumatoid disease, and 1 for papillary flap rupture after 5.1 years. Mortality was 1 perioperative (1.9%, nonvalve related) and 1 after reoperation due to multiorgan failure. During late follow-up (30 +/- 7 months postoperatively) 5 patients died of noncardiac causes. Regular echocardiographic control revealed good SMV function (maximum transmitral blood flow velocity 1.7 +/- 0.2 m/s; mean transmitral pressure gradient 3.9 +/- 1.2 mm Hg) and well-preserved ejection fraction postoperatively as well as at most recent follow-up. CONCLUSIONS: The clinical experience after 5.5 years of SMV implantation is promising. Preservation of annuloventricular continuity is advantageous. However, long-term durability remains to be proved.

Aged↗

PubMed2005

Stentless mitral valve replacement by conventional and minimally invasive techniques.

Stentless mitral valve (SMV) replacement is an intriguing concept to preserve the functionality of the physiological mitral valve (MV). Beginning in August 1997 to date, 51 patients, 35 females and 16 males (age: 68.3+/-8.4 years), with severe MV disease (stenosis 25, incompetence 17, mixed lesion 9) received a chordally supported SMV. SMV implantation was performed using a conventional sternotomy in 32, or a minimally invasive lateral minithoracotomy approach in 19 of the patients. Mean valve size was 29+/-1.5 mm; cross-clamp duration was 81+/-33 min. The perioperative mortality rate was comparable to conventional MV repair or replacement. Regular echocardiographic control disclosed good SMV function (Vmax 1.7+/-0.2 m/s, Pmean 3.9+/-1.2 mmHg) and well-preserved ejection fraction postoperatively, as well as at their most recent follow-up visit. SMV implantation by way of a sternotomy or lateral minithoracotomy leads to preservation of the annulo-ventricular continuity and similar to physiological hemodynamics. However, long-term durability remains to be proven.

Aged↗

PubMed2004

Prospectively randomized evaluation of stented xenograft hemodynamic function in the aortic position.

BACKGROUND: Standard stented aortic xenograft valves have not yet been compared regarding their hemodynamic function using a stratified intraoperative randomization protocol. METHODS AND RESULTS: 100 patients were prospectively included after intraoperative metric sizing of the decalcified aortic annulus. They received Mosaic (M) or Perimount (P) aortic valve replacement. Patient age was 73+/-5 years, 51 were female, and New York Heart Association (NYHA) functional class was 2.8+/-0.5. The 21-mm annulus group consisted of 5 (M)/7 (P) patients, the 23-mm annulus group of 20 (M)/20 (P), the 25-mm annulus group of 18 (M)/19 (P), and the 27-mm annulus group of 4 (M)/7 (P) patients, respectively. Hemodynamic function was evaluated using transthoracic echocardiography before discharge and at follow-up (438+/-352 days). Surgery was uncomplicated in all patients. Labeled valve sizes were 0.93 (M) and 1.05 (P) mm smaller than the annulus diameters (p=NS). In-hospital mortality was 5%, all nonvalve-related. Transvalvular blood flow velocities and transvalvular pressure gradients were significantly lower in the 25 P versus the 25 M group at baseline and in the 23 P and 25 P groups at follow-up. There was a significant regression of left ventricular mass index in all patients at follow-up. However, left ventricular mass regression was more pronounced after P aortic valve replacement. CONCLUSIONS: Labeled sizes of prosthetic heart valves implanted are smaller than the true aortic annulus. Both standard aortic xenografts compared in this prospectively randomized trial provide a sufficient hemodynamic and functional outcome.

Aged↗

PubMed2004

Restitution of sinus rhythm plus stentless mitral valve replacement at three years.

BACKGROUND AND AIM OF THE STUDY: The study aim was to examine results after stentless mitral valve (SMV) replacement (Quattro) and restitution of physiological cardiac rhythm by intraoperative left atrial ablation therapy. METHODS: Twenty patients (13 females; mean age 69.7 +/- 5.9 years) with severe degenerative mitral valve disease (six with valve stenosis, six with valve incompetence, eight with combined lesion) were prospectively evaluated since 1998. The mean NYHA functional class was 3.2 +/- 0.4, and cardiac index 1.8 +/- 0.5 l/min/m2. Ablation therapy was performed by inducing left atrial linear lesion lines to avoid reentrant circuits. RESULTS: Surgery was performed using conventional sternotomy (n = 10) or lateral minithoractomy (n = 10). Sinus rhythm was successfully restituted in 17 patients either postoperatively or in the long term (success rate 85%). However, three patients required DDD-pacemaker implantation, and another three had to be discharged with persistent atrial fibrillation. Intermittent medical therapy (sotalol or amiodarone) was required in nine patients postoperatively, in four patients at six months, and in two patients at one-year follow up. One patient was reoperated on for paravalvular leak after one year, but subsequently died due to sepsis. In the other patients, echocardiographic control proved good SMV function with atrial contraction. CONCLUSION: Restitution of physiological cardiac function is possible by combined stentless MV implantation and left atrial ablation therapy. A persistent benefit, without need for additional re-intervention, was shown at mid-term follow up.

Aged↗

PubMed2004

Early results with stentless mitral valve replacement.

BACKGROUND AND AIM OF THE STUDY: Implantation of a chordally supported stentless mitral valve (SMV) may be the strategy of choice for patients with severe degenerative mitral valve disease. Herein, the early clinical results of this surgical technique were analyzed. METHODS: Since August 1997, 52 patients (36 females, 16 males; mean age 68.0 +/- 8.5 years) each received a SMV (Quattro; St. Jude Medical Inc.) at the authors' institution. The underlying disease was predominant mitral stenosis (n = 26), incompetence (n = 17) and combined lesion (n = 9). The mean NYHA class was 3.1 +/- 0.6, left ventricular ejection fraction 64 +/-13%, and cardiac index 2.1 +/- 0.8 1/min/m2. RESULTS: SMV implantation was performed using either a conventional sternotomy (n = 33) or a lateral minithoracotomy (n = 19). The mean implanted valve size was 29.2 +/- 1.7 mm, and mean cross-clamp time 81 +/- 33 min. Reoperation was required in six patients: two for paravalvular leakage, two for functional stenosis (both 26 mm valves), in one patient for pannus formation with underlying collagenosis, and in one for papillary flap rupture at five years. One patient died perioperatively, one died after reoperation at one year, and five patients died at longer follow up, from non-cardiac causes. Hemodynamic function was shown to be normal on echocardiography. CONCLUSION: Intermediate-term results after SMV implantation were promising. Preservation of annuloventricular continuity led to good left ventricular function, but long-term durability remains to be proven.

Aged↗

PubMed2003

Midterm results after stentless mitral valve replacement.

BACKGROUND: To analyze the midterm clinical results after stentless mitral valve (SMV) replacement. METHODS AND RESULTS: Fifty one patients (68.3+/-8.4 years, 35 female) with severe mitral valve disease (stenosis 25, incompetence 17, mixed lesion 9) received a chordally supported SMV (Quattro, St. Jude Medical Inc.) since August 1997. Preoperative New York Heart Association class was 3.1+/-0.6; left ventricular ejection fraction 64+/-13%, and cardiac index 2.1+/-0.8 l/min/m2. Additional intraoperative ablation therapy was performed on 19 patients with chronic atrial fibrillation. Mean follow-up is 35.4+/-19.2 months (range 5 to 63). SMV implantation was performed using a conventional (32) or a minimally invasive (19) approach, valve size was 29+/-1.5 mm, cross-clamp duration was 81+/-33 minutes. Atrial rhythm was reestablished in 16 of 19 patients. Five patients required reoperation early in this series, two for paravalvular leakage, two for functional stenosis, and one with underlying rheumatoid disease. Mortality was one perioperative (1.96%, non-valve-related), one after reoperation as a result of multiple organ failure (MOF), and five during late follow-up (30+/-7 months postoperatively) for noncardiac causes. Regular echocardiographic control revealed good SMV function (Vmax 1.7+/-0.2m/s, P(mean) 3.9+/-1.2 mm Hg) and well-preserved ejection fraction postoperatively and at most recent follow-up. CONCLUSIONS: Midterm results after SMV implantation are promising. Preservation of the annuloventricular continuity leads to stable left ventricular function and combined with ablation therapy to physiological hemodynamics. Long-term durability remains to be proven.

Aged↗

PubMed2002

Experimental evaluation and early clinical results of a new low-profile bileaflet aortic valve.

We performed an experimental and clinical evaluation of a new low-profile bileaflet aortic valve (Regent, St. Jude Medical Inc., St. Paul, MN, U.S.A.). Common valve sizes were experimentally tested for leakage volume, pressure drop, and transvalvular hemodynamics using a pulse duplicator. Thirty patients (mean age 60 +/- 7 years, predominant valve stenosis n = 25) received the Regent prosthesis for initial clinical evaluation. In vitro evaluation revealed equivalent leakage volumes, larger performance indices (0.552 versus 0.513), and lower pressure drops in comparison to SJM hemodynamic plus valve controls. Clinically, 21 mm (n = 9), 23 mm (n = 12), and 25 mm (n = 9) valves were implanted with no significant perioperative complications. Echocardiography revealed low transvalvular flow velocities (2.2 +/- 0.4 m/s) and low pressure gradients (20 +/- 6 mm Hg) postoperatively and at 6 months follow-up. In vitro testing and early clinical results are promising; however, long-term performance has to be proven.

Aged↗

PubMed2002

Hemodynamic evaluation of stentless mitral valve replacement.

The purpose of this study was to evaluate the perioperative and postoperative hemodynamic function of recently introduced stentless mitral valves (SMVs). Forty-two selected patients who had received the SMV since 1997 had preoperative, postoperative, and follow-up transthoracic echocardiographic (TTE) examinations. Transesophageal echocardiography (TEE) was applied routinely during the operation as well as postoperatively if indicated. Adequate SMV function was seen in all patients perioperatively. Echocardiographic prediction of valve size and of papillary muscle distances was correct in 37 of 42 patients. Transvalvular blood flow velocities were 1.6 +/- 0.2 m/s postoperatively versus 1.8 +/- 0.3 m/s at 1 year and 1.7 +/- 0.3 m/s at 3-year follow-up. Mean transvalvular gradients were 4.3 +/- 1.6, 3.8 +/- 1.9, and 4.7 +/- 1.1 mm Hg, respectively. TEE and TTE are extremely useful to assist SMV implantation as well as for regular follow-up evaluation. The hemodynamic function after SMV implantation with preservation of the annulo-ventricular continuity is promising.

Aged↗