Showing papers by "Volkmar Falk published in 2003"

Mitral valve repair in patients with end stage cardiomyopathy: who benefits?

Abstract: Objective: Patients with end stage cardiomyopathy frequently present with additional severe mitral regurgitation. We analyzed the outcome of mitral valve reconstruction in this high risk patient group. Methods: Sixty-six patients with significant mitral regurgitation and an ejection fraction (EF) below 30% (dilated cardiomyopathy ¼ 53, ischemic cardiomyopathy (ICM) ¼ 13) were retrospectively evaluated from 07/96 and 02/02. All received annuloplasty ring implantation and additional repair (n ¼ 4) if required. Mean follow-up was 28 ^ 18 months. Results: Mitral valve repair (MVR) was technically feasible in all patients. Intraoperative transesophageal echocardiography (TEE) revealed none (n ¼ 60) or only trivial (n ¼ 6) residual mitral regurgitation. Thirty day mortality was 6.1%. Actuarial survival after 1 and 5 years was 86 ^ 4 and 66 ^ 8%, respectively. During follow-up seven patients were transplanted due to lack of clinical improvement after 10 ^ 7 months (range 1 ‐ 23). Echocardiography revealed a significant improvement in EF (25 ^ 10.5% preop, 34 ^ 15% post-op) and a slight decrease in left ventricular end-diastolic diameter (69 ^ 10 mm pre-op, 67 ^ 13 mm follow up). Patients were in NYHA functional -class 3 (median) preoperatively and in class 2 at long term-follow-up. Gender, left ventricular enddiastolic diameter, preoperative ejection fraction or type of surgical approach (sternotomy, right lateral minithoracotomy) had no significant influence on patient outcome. Patients with ICM or patients older than 60 years showed an increased risk for clinical events both early post-operatively and at long-term follow-up. Conclusion: MVR can be performed with low perioperative morbidity and mortality even in patients with advanced heart failure, modifying selection criteria for potential candidates may further improve long term outcome. q 2003 Elsevier Science B.V. All rights reserved.

Short- and long-term hemodynamic effects of intra-aortic balloon support in ventricular septal defect complicating acute myocardial infarction.

Abstract: In patients with an infarct-related ventricular septal defect, an intra-aortic balloon pump provides immediate and long-term hemodynamic improvement, resulting in an enhanced effective cardiac output and a reduced left-to-right-shunt and shunt flow ratio. In patients who can be stabilized or remain stable, there is no habituation to the effects of the intra-aortic balloon pump; thus, later surgical closure of the ventricular septal defect might be possible in some selected patients.

Temporary extracorporeal membrane oxygenation in patients with refractory postoperative cardiogenic shock--a single center experience.

Abstract: Background: Approximately 1% of patients require temporary circulatory support due to refractory cardiogenic shock following cardiac surgery. Such patients are at very high risk for subsequent morbidity and mortality. We evaluated the results of temporary extracorporeal membrane oxygenation (ECMO) support in patients with postcardiotomy cardiogenic shock. Methods: From November 1997 to February 2000, 7900 patients underwent cardiac surgery in our institution. Ninety-five patients (1.2%) (CABG, n = 63; AVR, n = 16; CABG and AVR, n = 8; other procedures, n = 8) required temporary postoperative ECMO support. ECMO implantation was performed via the femoral vessels or via the right atrium and ascending aorta. Intraaortic balloon counterpulsation was employed in all patients. Results: Mean duration of ECMO support was 2.8 ± 2.1 days. Forty-five patients (47%) were successfully weaned from ECMO. Of these, 28 patients were discharged from hospital 35.8 ± 20.8 days post-ECMO support. Overall hospital mortality for all ECMO patients was considerable at 71%. Mortality rate in the combined CABG and AVR group was 100% (P < 0.05 versus the other surgical groups). ECMO support was complicated by renal failure in 64% of patients, bleeding requiring mediastinal reexploration in 62%, ischemia of the lower limbs in 16%, cerebral edema in 6%, and cerebral hemorrhage in 3%. Conclusions: ECMO is a suitable technique for short-term treatment of refractory postoperative low cardiac output. Mortality rates are comparable to other cardiac assist devices, with approximately 30% of patients able to be discharged from hospital. (J Card Surg 2003;18:512-518)

Interactive Guidance by Image Overlay in Robot Assisted Coronary Artery Bypass

Abstract: We present an original visual guidance system in the especially difficult context of robot assisted coronary artery bypass graft. The overlay of a preoperative coronary tree model on the endoscopic images is initialized to help the surgeon to locate himself. Then the surgeon points some landmarks observed in the operating field during the motion of the endoscope. The overlay is corrected in real-time and the landmarks are automatically identified through a multi-model estimation method until the precision necessary to the localization of the surgical targets is reached. The first in vivo experiment, presented here, has shown the efficiency of the system by identifying the main arteries in a few clicks.

Midterm results after stentless mitral valve replacement.

Abstract: 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/m 2 . 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 (V max 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.

Coronary artery bypass grafting in patients with systemic lupus erythematosus.

Abstract: Cardiac involvement in patients with systemic lupus erythematosus (SLE) is common. The natural history of the cardiovascular manifestations has been altered by systemic corticosteroids used for the treatment of SLE; thus, young patients with SLE may suffer from angina and myocardial infarction. The surgical problems and special requirements in patients with SLE are discussed. CAD is one of the major complications limiting the prognosis of the patient with SLE. In the future, a large number of SLE patients may be candidates for myocardial revascularization. In our opinion, total autogenous arterial bypass grafting is advised and intraoperative biopsies of the LIMA are meaningful in patients with SLE.

Telemanipulator-gestutzte Applikation eines magnetischen Gefäss-Kopplers am schlagenden Herzen mit dem da Vinci-Surgical-System

Abstract: The construction of a coronary anastomosis on the beating heart under totally endoscopic conditions is technically demanding. In this study the potential benefits of an endoscopic magnetic vascular coupler (MVP, Ventrica,Inc, Fremont, CA) designed to facilitate construction of a coronary anastomosis with the help of the da Vinci telemanipulator (Intuitive Surgical inc., Sunnyvale, CA) were evaluated in a totally endoscopic coronary arterial bypass (TECAB) operation on the beating heart in eight dogs. The telemanipulated instruments were used to guide and place the endoscopic MVP-application platform (prototype). All animals underwent angiography, and gross inspection of the anastomotic site was done after excision of the hearts. The procedure was accomplished in 169 minutes (155-190). With the exception of one premature deployment, all MVP-anastomoses were accomplished in 3 minutes (1-28). The following adverse events were encountered: Bleeding from the right ventricle caused by occlusion tape (1), anastomotic leakage upon reperfusion requiring repair stitches (2), anastomotic occlusion due to a thrombus (1). All but one animal that died on reperfusion despite a patent graft and anastomosis, survived the procedure. Overall patency was 7 out of 8. The combination of telemanipulator technology allowing increased manipulation dexterity in a total endoscopic environment and the effective and time saving magnetic technique for anastomotic coupling has the potential to facilitate TECAB on the beating heart.

Limitations for manual and telemanipulator-assisted motion tracking and dexterity for endoscopic surgery

Abstract: Background: Surgical precision is limited by human factors. Surgery on a moving object requires full dexterity and motion tracking. Currently, techniques for total endoscopic surgery using telemanipulation systems are being developed. Aim of this study was to assess the limitations for manual and telemanipulator-assisted motion tracking using the da Vinci™ telemanipulator system. Methods: To simulate moving object conditions, an endoscopic trainer was developed. Twenty subjects were asked to touch targets manually and with telemanipulator assistance with different patterns of increasing index of difficulty (resting model, unstabilized and stabilized model with a frequency of 35, 60 and 90/bpm). In addition, one task was performed using different scaling ratios on a resting model. The times between hits as well as misses were electronically recorded. Results: There was no significant impact of various frequencies and amplitudes for manual tracking. The average values for the delay (km [ms]) and information-processing (cm [ms/bit]) constants for the manual tasks were 201 and 86 ms/bit, respectively. As compared to manual control, the delay constant for the telemanipulator-assisted tasks of resting targets was three times longer (kt=630 ms; p

Thorascopic coronary surgery. Current status and future perspectives

Abstract: Thorascopic coronary surgery has achieved great progress in the past few years After computer-directed instrument systems were introduced, which enabled high precision and expanded mobility in close quarters, the limitations of conventional endoscopic instruments were largely overcome Employing modern surgical telemanipulators and endoscopic stabilizers, entirely endoscopic myocardial revascularization of the anterior wall is being successfully performed during off-pump surgery Longer operating times and conversion rates in about one-fifth of the patients due to technical and anatomical limitations still restrict the use of these new surgical techniques compared to conventional surgery Development of further technologies and integration of video-assisted navigation systems will broaden the application of computer-assisted instrument systems in the near future

Telemanipulatory application of a magnetic coupler on the beating heart with the daVinci surgical system

Abstract: The construction of a coronary anastomosis on the beating heart under totally endoscopic conditions is technically demanding. In this study the potential benefits of an endoscopic magnetic vascular coupler (MVP, Ventrica, Inc, Fremont, CA) designed to facilitate construction of a coronary anastomosis with the help of the daVinci telemanipulator (Intuitive Surgical Inc., Sunnyvale, CA) were evaluated in a totally endoscopic coronary arterial bypass (TECAB) operation on the beating heart in eight dogs. The telemanipulated instruments were used to guide and place the endoscopic MVP-application platform (prototype). All animals underwent angiography, and gross inspection of the anastomotic site was done after excision of the hearts. The procedure was accomplished in 169 minutes (155-190). With the exception of one premature deployment, all MVP-anastomoses were accomplished in 3 minutes (1-28). The following adverse events were encountered: Bleeding from the right ventricle caused by occlusion tape (1), anastomotic leakage upon reperfusion requiring repair stitches (2), anastomotic occlusion due to a thrombus (1). All but one animal that died on reperfusion despite a patent graft and anastomosis, survived the procedure. Overall patency was 7 out of 8. The combination of telemanipulator technology allowing increased manipulation dexterity in a total endoscopic environment and the effective and time saving magnetic technique for anastomotic coupling has the potential to facilitate TECAB on the beating heart.