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Biomedical subjects

M Dangel

Publications and source records attributed to M Dangel.

9 recordsLinked to original sources

New minimally invasive surgical technique using arterial T-grafts for treatment of double-vessel coronary artery disease: experimental study.

Minimally invasive surgery has been used successfully in patients with single-vessel coronary artery disease (CAD), but there are no clinical reports of surgical techniques for the treatment of multivessel disease in this field using both internal mammary arteries (IMAs). Therefore a canine model has been established to demonstrate the feasibility of a minimally invasive surgical treatment of coronary artery double-vessel disease using both IMAs. Ten mongrel dogs underwent bilateral thoracoscopic preparation of both internal mammary arteries through small left lateral chest ports. Using the Port Access endovascular cardiopulmonary bypass system the right IMA (RIMA) was anastomosed as a free graft end-to-side to the left IMA (LIMA) as a T-graft. After induction of cardioplegic arrest the RIMA was anastomosed to the circumflex artery and the LIMA to the left anterior descending artery. All animals were weaned from cardiopulmonary bypass without inotropic support. The electrocardiogram showed sinus rhythm with no signs of ischemia. Intraoperative coronary angiography demonstrated patency of all anastomoses. The minimally invasive surgical treatment of double-vessel CAD using arterial T-grafts of both IMAs is thus feasible. Surgical trauma can be further reduced by harvesting the RIMA transmediastinally through the left lateral chest.

Anastomosis, Surgical↗

Port-Access coronary artery bypass grafting with the use of cardiopulmonary bypass and cardioplegic arrest.

BACKGROUND: To reduce surgical trauma, we performed minimally invasive Port-Access (Heartport Inc, Redwood City, CA) coronary artery bypass grafting with cardiopulmonary bypass and cardioplegic arrest. METHODS: Thirty-six men and 6 women with a median age of 59 years (range, 31 to 75 years) and isolated lesions of the left anterior descending branch of the coronary artery underwent Port-Access coronary artery bypass grafting. A small (6- to 9-cm) incision was made parasternally on top of the fourth rib. The left internal thoracic (mammary) artery was dissected and taken down through the minithoracotomy either alone or using an additional thoracoscopic approach. Cardiopulmonary bypass was instituted through femoral cannulation, and an additional endoarterial balloon catheter (Heartport Inc) was introduced into the ascending aorta for aortic occlusion, aortic root venting, and the delivery of cold antegrade crystalloid cardioplegia. After cardioplegic arrest, the left internal mammary artery was anastomosed to the left anterior descending artery under direct vision. RESULTS: The median left internal mammary artery takedown time was 49.5 +/- 21.9 minutes, the duration of cardiopulmonary bypass was 59.5 +/- 32.8 minutes, the aortic occlusion time was 28.5 +/- 7.9 minutes, the intensive care unit stay was 1.0 +/- 3.2 days, and the total hospital stay was 5.0 +/- 2.5 days. Intraoperative angiograms were done in the first 10 patients and showed patent left internal mammary artery grafts without anastomotic complications in all cases. Two arterial dissections, including one aortic dissection, were observed in patients with preexisting peripheral vascular disease. The other complications were minor. All but 1 patient recovered well, with no major limitations in their daily activities. CONCLUSIONS: Using this minimally invasive method, sternotomy-related complications can be avoided, the hospital stay can be reduced, and a safe coronary artery bypass grafting procedure can be performed with the advantage of cardiopulmonary bypass and cardioplegic arrest as are used routinely in conventional coronary artery operations.

Adult↗

Minimally invasive bilateral internal mammary artery bypass grafting.

We report about a 71-year-old man with coronary artery double-vessel disease who received minimally invasive coronary artery bypass grafting through a 9-cm left lateral chest incision in the third intercostal space. Both mammary arteries were harvested either directly (left internal mammary artery) or thoracoscopically (right internal mammary artery) and anastomosed to the left anterior descending artery and the circumflex artery through this single left lateral chest incision. The postoperative course was uneventful, and the patient was discharged on postoperative day 5.

Aged↗

Minimally invasive mitral valve surgery--clinical experiences with a PortAccess system.

OBJECTIVE: This is the initial experience with a new minimally invasive surgical technique for the treatment of mitral valve disease using a PortAccess system. METHODS: Between May 1996 and May 1997, 21 patients (nine male, 12 female, aged 30-75 years, median 64 years) underwent minimally invasive mitral valve surgery. The underlying diseases were: mitral valve insufficiency (n = 11), mitral valve stenosis (n = 5) and combined mitral valve disease (n = 5). Through a small right thoracotomy (6-8 cm) access to the pericardium and the heart was gained. Cardiopulmonary bypass was instituted through femoral cannulation and an intraaortic balloon-catheter (Heartport Inc., Redwood City, CA) was introduced for aortic occlusion, aortic root venting and delivery of cold crystalloid cardioplegia. Mitral valve repair (four patients) or replacement (15 patients) was performed. RESULTS: There was no death during the whole follow-up period. There was no perivalvular leak and only minor residual mitral valve regurgitation was observed on intraoperative or postoperative (3 months) transesophageal echocardiography. There was no postoperative study-related complication. Time of ventilation, intensive care unit and hospital-stay were comparable with the data of patients undergoing conventional mitral valve surgery. CONCLUSIONS: This technique of PortAccess mitral valve surgery combines the advantage of less invasive operative trauma with the safety of conventional mitral valve surgery.

Female↗

Clinical experiences with minimally invasive mitral valve surgery using a simplified Port Access technique.

OBJECTIVE: Using the initial experiences with the Port-Access technique for the treatment of mitral valve disease some changes were made thus resulting in more simple and faster procedures. METHODS: Twenty-nine patients (13 male, 16 female, aged 30 to 75 years, median 62.5 +/- 11.0 years) underwent minimally invasive mitral valve surgery between May 1996 and December 1997. The underlying diseases were: mitral valve insufficiency (n = 16), mitral valve stenosis (n = 7) and combined mitral valve disease (n = 6). Through a small right thoracotomy (5-7 cm) access to the pericardium and the heart was gained. Cardiopulmonary bypass was instituted through femoral cannulation and an intraaortic balloon-catheter was introduced for aortic occlusion, aortic root venting and delivery of cold crystalloid cardioplegia. Mitral valve repair (five patients) or replacement (24 patients) was performed. RESULTS: There was no death during the whole follow-up period. There was no perivalvular leak and only minor residual mitral valve regurgitation was observed on intraoperative or postoperative (3 months) transesophageal echocardiography in three patients. There was no postoperative study-related complication. Time of ventilation and intensive care unit were comparable with the data of patients undergoing conventional mitral valve surgery but hospital stay was shorter in the last 10 consecutive cases. CONCLUSIONS: This simplified technique of mitral valve surgery combines the advantage of less invasive operative and good cosmetic results with the safety of conventional mitral valve surgery. At our institution this technique presents in well selected patients suffering from mitral valve disease the procedure of choice.

Cardiac Surgical Procedures↗

[A comparative study of minimal invasive harvesting of vena saphena magna segments].

From July 1997 to February 1998 we performed either minimally invasive or endoscopic saphenous vein harvesting in 55 patients and compared the results with those of 46 patients after conventional saphenous vein harvesting. Minimally invasive and endoscopical vein harvesting can be safely performed after a longer learning curve. Patients after minimally invasive and endoscopical saphenous vein harvesting showed fewer wound healing problems and better cosmetic results than after conventional vein harvesting.

Aged↗

Adhesion and migration are differentially regulated in hematopoietic progenitor cells by cytokines and extracellular matrix.

The conditions that control the migratory status of hematopoietic progenitor cells on extracellular matrix (ECM) and that decide whether a cell migrates or adheres are incompletely understood. We analyzed the migratory behavior of murine hematopoietic progenitor cells factor-dependent-cell-paterson (FDCP)-mix and purified lin-Sca1+ bone marrow cells on ECM. We found that migration on fibronectin (Fn) or laminin (Lam) becomes dependent on beta1-integrins if a surface restraint force is introduced by tilting the ECM-coated culture vessels. Under these conditions, migration specifically occured on Fn and Lam, and was not detected on collagen IV-, hyaluronate-, or bovine serum albumin- coated surfaces. Migration depended on the continuous presence of hematopoietic cytokines interleukin-3 (IL-3), granulocyte colony-stimulating factor (G-CSF), macrophage-CSF (M-CSF), granulocyte-macrophage-CSF (GM-CSF), or stem cell factor (SCF), whereas other cytokines, such as IL-8, macrophage inflammatory protein-1alpha, macrophage-chemotactic and activating factor, and erythropoietin resulted in very little or no migratory response. IL-3 induced migration was synergistically enhanced by other CSFs, but was completely inhibited by addition of transforming growth factor-beta1. In contrast to firm local adhesion of previously cytokine depleted progenitors that was rapidly inducible within 1 hour after exposure to cytokines, preincubation on Fn matrix for 4 to 6 hours was required before cytokines could induce migration. A sudden increase of cytokine concentration reversibly inhibited migration and induced a fully adhesive state; this effect could be prolonged by consecutive stimulation with heterologous cytokines. Whereas cytokines activated resting progenitor cells to migrate on ECM, cell migration speed was regulated by Fn concentration. These results indicate that beta1-integrin-mediated progenitor cell adhesion and migration are differentially regulated by external stimuli and suggest that this regulation corresponds to different activation states of beta1-integrins in hematopoietic progenitor cells.

Animals↗