Biomedical subjects

L K Von Segesser

Publications and source records attributed to L K Von Segesser.

9 recordsLinked to original sources

PubMed2002

Left atrial radiofrequency compartmentalization for chronic atrial fibrillation during heart surgery.

BACKGROUND: The excellent results of the Maze III operation have demonstrated that a surgical cure of atrial fibrillation (AF) is possible. A simplified Maze procedure with radiofrequency (RF)ablation of the atrial tissue added to open heart surgery may help to cure chronic AF with low risk. METHODS: From May 1998 to March 2001, an RF left atrial compartmentalization concomitant to a cardiac surgical intervention was performed on 40 of 1,258 patients (3.2 %). Thirty-seven patients had mitral valve disease, two had aortic valve disease and one had coronary artery disease. All patients presented with chronic refractory AF for a mean time of 40.4 months ranging from 4 months to 18 years. RESULTS: Mitral valve replacement (MVR) was performed in 19 patients, mitral valve repair in 12, combined aortic and mitral valve procedures were performed in 6, aortic valve replacement(AVR) in 2 and CABG in 1 patient. Cardiopulmonary bypass time for the complete procedure was 138 +/- 32 minutes with an ablation time of 19 +/- 5 minutes. No complication related to RF application was noted. Sinus rhythm was present in 68% after 12.5 +/- 8.5 months. CONCLUSIONS: RF left atrial compartmentalization combined with cardiac surgical interventions proved to be easy and safe to perform. The long-term results still have to be confirmed with further regular patient follow-up examinations.

Aged↗

PubMed2001

Systolic axial artery length reduction: an overlooked phenomenon in vivo.

To demonstrate axial artery motion during the cardiac cycle, the common carotid arteries (CCA) of 10 pigs were exposed and equipped with piezoelectric crystals sutured onto the artery as axial position detectors. An echo-tracking system was used to simultaneously measure the CCA diameter. For each animal, data for pressure, length, and diameter were collected at a frequency of 457 Hz. At a mean pulse pressure of 33 +/- 8 mmHg, the mean systolodiastolic length difference was 0.3 +/- 0.01 mm for a mean arterial segment of 11.35 +/- 1.25 mm. Systolic and diastolic diameters were 4.1 +/- 0.3 and 3.9 +/- 0.2 mm, respectively. The examined CCA segment displayed a mean axial systolic shortening of 2.7%. This study clearly demonstrates, for the first time, that the length of a segment of the CCA changes during the cardiac cycle and that this movement is inversely correlated with pulse pressure. It is also apparent that the segmental axial strain is significantly smaller than the diameter variation during the cardiac cycle and that the impact of the axial strain for compliance computation should be further evaluated.

Animals↗

PubMed2001

Endovascular treatment of aortic rupture by blunt chest trauma.

BACKGROUND: The usual treatment of blunt aortic injury (BAI) is prompt surgery. Frequently severe injuries to the brain or lungs exclude further surgical treatment. The purpose of this study is to assess the feasibility of placing endovascular stent-grafts. METHODS: From 1992 through 1999, in our primary and referral trauma center, 26 acute BAI, 21 males and 5 females, mean age 40.2+/-16.3 yrs were diagnosed. The last 4 patients underwent prospectively endovascular repair with Talent endograft. Endoprosthesis parameters were measured on three-dimensional spiral CT reconstruction. While waiting for devices, blood pressure was aggressively lowered and aortic lesions were monitored by transesophageal echography. RESULTS: Stent-graft deployment was successful in all 4 patients. There were no complications of endoleak, stent migration, paraplegia or death. Angiographic exclusion was complete in all 4 patients. CT scans at a mean follow-up of 11+/-5 months showed complete healing of the aortic wall in all patients. CONCLUSIONS: For stable acute BAI, endovascular stent-graft repair is feasible and safe, and is an effective therapeutic alternative to open surgery. Because of the normal proximal and distal wall in aortic injuries, endoluminal treatment might be the therapy of choice in the near future.

Adult↗

PubMed2000

[Closure of an atrial septal defect by a mini-thoracotomy with the help of extra-corporal circulation].

AIM OF THE STUDY: "Minimal invasive" surgical closure of an atrial septal defect (ASD) is performed under femoro-femoral CPB, the superior vena cava being (IVC) drained by a supplementary cannula placed directly through the thoracic opening. We present a new technique where both vena cavae are drained by a single 2 stage femoral cannula. METHODS: The cannula is introduced through the femoral vein and its distal holes are directed into the superior vena cava (SVC) while the proximal holes are maintained into the IVC. A centrifugal pump is placed on the venous line between the cannula and the venous reservoir in order to improve the venous return. Both IVC and SVC are clamped around the cannula to isolate the right atrium before opening it and repairing the ASD. RESULTS: We recently operated on a 60 years old man using this technique. Passive venous drainage was 2.6 l/min whereas the perfusion theoretical flow was 5.4 l/min. But adding the centrifugal pump increased the flow to 5.4 l/min which ensured an optimal perfusion flow. CPB time was 38 minutes and operative time was 140 minutes. There were no complications and the patient returned home at day 5 following the operation. CONCLUSIONS: Using a single venous cannula for drainage of both vena cavae simplifies the technique and therefore contributes to the development of "minimally invasive" cardiac surgery.

Cardiopulmonary Bypass↗

PubMed1999

Trillium coating of cardiopulmonary bypass circuits improves biocompatibility.

Coating of cardiopulmonary bypass circuits may be a solution to prevent adverse effects induced by contact of blood elements with foreign surfaces. Using an animal model, we investigated the Trillium TM coating of cardiopulmonary bypass circuits (a new process involving polyethylene oxide, sulphonate groups and heparin) at low systemic heparinization, focusing on haemolysis and clot formation. Cardiopulmonary bypass was initiated through jugulo-carotid access with ACT maintained around 180 sec. Treated circuits (Trillium group) were evaluated in 3 calves (mean weight of 66.0+/-8.7 kg), vs. untreated circuits in 3 control calves (mean weight of 60.7+/-7.5 kg). Blood samples were drawn at regular intervals for biochemical, hematological and blood gas analyses. After 6 consecutive hours, the animals were weaned from CPB and were awakened. The circuits were analyzed for clot deposits. After 7 days the animals were sacrificed and an autopsy was carried out. Red cell and white cell counts did not change over the 6 hours. Platelet counts dropped to 75.9+/-7.3% of the baseline value in the Trillium group after 6 hours whereas counts dropped to 57.2+/-26.0 in the control group (p<0.05). Plasma free Hb remained constant in the Trillium group but increased significantly to 280+/-65% of baseline value in the control group (p<0.05). The amount of clots were significantly higher in the control group, in the connectors, the reservoir, the heat exchanger, and the oxygenator. No renal emboli were seen in the Trillium group whereas the mean number of emboli was 3.0+/-2.4 in the control group. We conclude that Trillium coating significantly improves the biocompatibility of artificial surfaces exposed to blood.

Animals↗

PubMed1997

Aortic dissection.

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Aortic Dissection↗

PubMed1996

Congenital coronary fistulas in children and adults: diagnosis, surgical technique and results.

Coronary artery fistula is a very rare congenital malformation with abnormal coronary-cameral communication that may involve any chamber and any or all coronary artery branches. We present our experience with 11 consecutive patients [mean age 16.6 years, ranging from 4 to 64 years]; 9 of them were treated surgically, spontaneous closure of the fistula was observed in one patient and one patient is still under observation. Fistulas originated from the right coronary artery in 4 patients and drained either into the right [n=3] or into the left system [n=1]. In 9 patients, the fistulas originated from the left coronary system and the fistulous communication developed with the right cardiac structures only. In 2 patients both coronary arteries were involved in the pathological drainage and 2 patients were demonstrated to have multiple drainage from the left coronary artery. Additional congenital cardiac malformations were found in 2 patients. Surgical closure of the fistula was successful in all operated patients [in one case treatment was possible without cardiopulmonary bypass]. Simple ligation of the fistula was performed in 1 patient, intracardiac closure of the fistula was combined with different reconstructive procedure in the other patients. Neither hospital mortality nor severe complications occurred. Mean follow-up interval was 39.4 months and all patients except one were in NYHA I. In presence of symptoms of congestive heart failure, significant left-to-right shunt and arrhythmias, elective closure of coronary fistula is generally accepted, whereas indication is more controversial in asymptomatic patients.

Adolescent↗

PubMed1993

Sternal cleft associated with vascular anomalies and micrognathia.

Sternal defects combined with craniofacial vascular defects are rare. We report on a 45-year-old woman with a sternal cleft associated with craniofacial and brain hemangiomata, an aneurysm of the aortic arch, anomalous origin of the coronary arteries, a left superior vena cava, micrognathia, supraumbilical midline raphe, and a cervical cyst. The surgical procedure consisted of the resection and replacement of the aortic arch and the innominate artery with reimplantation of the left carotid artery into the graft under circulatory arrest and deep hypothermia. The presence of sternal cleft is an indication for the search for other asymptomatic internal vascular anomalies.

Abnormalities, Multiple↗

PubMed1992

Improved biocompatibility of heparin surface-coated ventricular assist devices.

Heparin surface coated ventricular assist devices (VADs) and cannulas were evaluated in comparison to uncoated VADs in 10 bovine experiments (body weight 77 +/- 6 kg). All systems were primed with cristalloid solution. No systemic heparin was given. Left ventricular assist was started with a blood flow of 4.2 +/- 0.4 l/min and maintained over 6 hours. Besides hemodynamic monitoring, blood samples were taken at regular intervals for blood gas, hematological, biochemical and coagulation studies. All animals in the study group (coated) were assisted for the scheduled 6 hours without device failure. In the control group, however, total occlusion occurred in 1 VAD after 1 hour of left ventricular assist whereas the other 4 VADs remained functional throughout the protocol. Mixed venous oxygens saturation was preassist 56 +/- 12% for coated versus 63 +/- 11% for uncoated and the final value at 60 minutes after weaning was 58 +/- 16% versus 59 +/- 5% (NS). Mean hematocrit dropped from a baseline value of 33 +/- 4% for coated versus 29 +/- 8% for uncoated to 29 +/- 7% versus 30 +/- 5% (NS) after 6 hours of assist. There was no significant difference between the baseline values (5.7 +/- 3.0 mumol/l for coated versus 4.6 +/- 3.1 mumol/l for uncoated) and the 6-hour values (3.8 +/- 3.7 mumol/l versus 7.6 +/- 6.4 mumol/l) for mean plasma hemoglobine. The normalized platelet levels dropped after 10 minutes of assist to 91 +/- 21% for coated versus 94 +/- 49% for uncoated (NS) and 89 +/- 29% versus 65 +/- 44 at 6 hours (NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗