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Biomedical subjects

U Klima

Publications and source records attributed to U Klima.

At least 19 recordsLinked to original sources
PubMed2005

[Breast cancer -- plastic surgical strategies for the treatment of tumour infiltration of the thoracic wall and brachial plexus].

Extensive locoregional recurrency or metastatic involvement of brachial plexopathy is a condition that is often associated with advanced systemic breast cancer. In the past the role of surgeon was restricted due to a scepticism as to whether any benefit will be provided for the patient. In the recent 25 years however safe and refined plastic surgical approaches have been developed that provide more options to treat even complex recurrent disease. The strategy of plastic surgery in an interdisciplinary approach of gynecology, oncology and radiotherapy as well as thoracic surgery is outlined.

Breast Neoplasms↗
PubMed2005

[Preliminary clinical experience with the Ventrica automatic distal anastomosis system in coronary surgery].

The surgical treatment of coronary lesions is based on bypassing the anatomical lesions with autologous vascular grafts. This procedure has traditionally been "invasive", requiring a micro-surgery technique, institution of extra-corporeal circulation, as well as temporary cardiac arrest with a cardioplegic solution. Recently, an automatic distal anastomosis procedure has been developed (Ventrica, Medtronic Inc.), based on a magnetic coupling with two implanted intravascular magnets, allowing easy connection between the graft and the coronary artery. The immediately obvious advantages are the time saved, ease of use, reproducibility and reliability. The learning curve is fast. Furthermore, the use of this automatic process does not compromise a manual anastomosis in case of implantation failure. The immediate post-operative results, as well as angiography immediately and at 6 months are all satisfactory. This technique is applicable for multiple revascularisations, all types of autologous grafts, terminal or sequential bypasses, as well as nearly all types of coronaries. The contribution to beating heart, closed thorax coronary surgery seems equally promising.

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PubMed2003

Microcirculation of the sternum following harvesting of the left internal mammary artery.

BACKGROUND: Internal thoracic arterial grafts (ITA) in coronary artery bypass surgery provide excellent long-term patency results. Due to the elevated incidence of sternal infections following pedicled ITA harvesting, blood supply to the sternum has gained the focus of attention. This study sought to evaluate real time parameters of sternal microcirculation prior and immediately after harvesting of the ITA by a novel laser Doppler flowmetry and remission spectroscopy system (Oxygen-To-See (O2C), LEA Medizintechnik, Giessen). METHODS: 21 patients (16 males, age 63 + 4 years, mean NYHA 2.3 +/- 0.3) scheduled for coronary artery bypass grafting (CABG) were enrolled into the study. After median sternotomy, the probe was placed sequentially pre- and retrosternally for measurements of tissue oxygen saturation (sO2), hemoglobin concentration (rHb), superficial (2 mm) und deep (8 mm) blood flow. Measurements were performed and analyzed before and after surgical harvesting of the ITA with a pedicle. RESULTS: Baseline pre- and retrosternal tissue oxygen saturation (sO2) were 90 +/- 3 % and 87 + 4 %, respectively (n. s.). After left ITA harvesting, presternal sO2 remained unchanged (90 + 4 %, n. s.), whereas retrosternal sO2 decreased significantly (54 + 4 %, p < 0.001). Simultaneously, retrosternal post-capillary venous filling (rHb) increased significantly after ITA harvesting (86 +/- 2 vs. 93 + 2, p < 0.05), whereas presternal rHb remained unchanged. Retrosternal superficial and deep blood flow also decreased significantly (75 +/- 5 vs. 41 +/- 4, and 94 +/- 5 vs. 52 +/- 6) in contrast to comparable presternal blood flow before and after ITA harvesting. There were neither superficial nor deep sternal wound infections occurred in the studied patient population. CONCLUSIONS: The pedicled harvesting of ITA leads to a significant decrease of microcirculatory blood flow, retrosternal tissue oxygen saturation, and an increase in post-capillary venous filling. Parameters of microcirculation in the presternal area after ITA harvesting remained unchanged compared to baseline values. Hence, the incidence of sternal infections after ITA harvesting in coronary surgery may well be explained by a significant decrease of sternal blood supply in the retrosternal area. Further prospective randomized studies are needed to elucidate the potential role of skeletonized ITA preparation in sternal microcirculation.

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PubMed2001

[A new combined surgical interventional method for univentricular palliation of congenital heart defects].

UNLABELLED: Total cavo-pulmonary anastomosis is frequently performed to palliate patients with a broad variety of congenital heart defects with functionally univentricular hearts precluding biventricular circulation. In patients with risk factors for primary repair a stepwise approach is frequently chosen with initial creation of an aorto-pulmonary shunt followed by a Glenn anastomosis or hemifontan procedure. Finally a total cavo-pulmonary connection is completed surgically. The aim of this feasibility study was to develop a combined surgical-interventional approach for creation of a total cavo-pulmonary anastomosis which reduces the number of surgical interventions, precludes extracorporeal circulation and intracardiac sutures, putting the patients at risk for subsequent rhythm disturbances. METHODS: A Glenn anastomosis was created in 10 sheep without cardio-pulmonary bypass. The superior vena cava was banded superior to the cavo-atrial junction leaving a minimal lumen for subsequent interventional balloon dilatation and implantation of a stent graft. A 15 mm Gore-Tex tube was sutured around the inferior vena cava intrapericardially to provide resistance for subsequent interventional stent implantation. Total cavo-pulmonary anastomosis was completed interventionally by dilating the banded vena cava superior and connection of the inferior vena cava to the superior vena cava by implanting an Aneurx covered stent graft. RESULTS: All animals survived the combined surgical-interventional procedure. Stent deployment was possible without causing obstruction to the hepatic veins. Neither stent dislocation nor rhythm disturbances were encountered. CONCLUSIONS: Total cavo-pulmonary anastomosis can be achieved without intracardiac sutures and cardio-pulmonary bypass by use of a combined surgical-interventional approach using the Aneurx covered stent graft.

Animals↗
PubMed2001

Minimally invasive removal of a dislocated stent from the right atrium after previous CABG.

Repeat sternotomy after previous open heart operations constitutes a serious risk factor for cardiac injury, particularly in the presence of a patent internal thoracic artery. We report a case of successful minimally invasive removal of a dislocated subclavian vein stent entangled in the tricuspid valve in a patient 5 years after coronary artery bypass surgery.

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PubMed2000

Effects of minimal invasive coronary artery bypass on pulmonary function and postoperative pain.

BACKGROUND: Minimally invasive direct coronary artery bypass (MIDCAB) requires substantially smaller incisions than conventional coronary artery bypass grafting (CABG). We investigated whether this fact may lead to less postoperative pain and improved pulmonary function. METHODS: Preoperative and postoperative (days 1, 3, and 5) pulmonary function and postoperative pain were assessed in 15 patients undergoing MIDCAB (group A) by using a standardized score and were compared with 15 patients admitted for CABG (group B). RESULTS: Total operation time (140 minutes versus 189 minutes; p<0.001) and duration of mechanical ventilation (300 minutes versus 840 minutes; p<0.001) were significantly less in group A. Pulmonary function was comparable between the 2 groups on postoperative day 1 (POD 1). Vital capacity was significantly greater in group A on POD 3 (59.7% versus 40.6%; p<0.001) and on POD 5 (74.4% versus 53.9%; p<0.001). Similar results were found for forced expiratory volume in 1 second (group A versus B on POD 3: 56.3% versus 42.2%; p<0.05; and on POD 5: 68.4% versus 55.5%; p<0.01). Postoperative pain was significantly higher in group A (POD 1: score 5.5 versus 3.6; POD 3: 4.0 versus 2.9; p<0.01). CONCLUSIONS: MIDCAB procedures lead to better preservation of pulmonary function compared with conventional CABG despite greater postoperative pain.

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PubMed2000

Mini-sternotomy for off-pump coronary artery bypass grafting.

The number of off-pump coronary artery bypass grafting procedures without cardiopulmonary bypass is steadily increasing. We report on a new, minimally invasive surgical approach for off-pump coronary revascularization in multivessel disease. A distal sternotomy is performed to gain access to the left and right internal thoracic arteries and to reach the left anterior descending coronary artery, diagonal branches, and right coronary artery for off-pump revascularization.

Coronary Artery Bypass↗
PubMed2000

Improved right ventricular function after intracoronary administration of a C1 esterase inhibitor in a right heart transplantation model.

OBJECTIVE: Myocardial injury from ischemia can be augmented after reperfusion due to proinflammatory events including complement activation, leukocyte adhesion, and release of various chemical mediators. It has been shown that intracoronary administration of a C1 esterase inhibitor (C1 INH) significantly reduces myocardial necrosis in an experimental model of ischemia. Our study addresses the question whether the most susceptible region of the heart for ischemic injury, the right ventricle (RV), can benefit from the protective effects of C1 esterase inhibition after transplantation. METHODS: To precisely control RV volume in vivo an isovolumic model was used in which the RV volume was regulated using an intracavity high compliance balloon inserted into donor hearts of domestic pigs (34+/-4 kg). After 4 h of ischemia, donor hearts were transplanted into recipient pigs (44+/-4 kg). Treatment groups, each with six animals, consisted of C1 INH treatment or control. After opening the cross clamp, the C1 INH group animals received 20 IU/kg body weight of C1 INH intracoronary over a 5 min period. The control animals received no drug therapy. The hearts were reperfused for 60 min, and thereafter the RV balloon volume was increased in 10 ml increments until RV failure occurred. These measurements were repeated after 120 min of reperfusion. RESULTS: There was no significant difference in maximal RV developed pressure between the two groups (after 1 h, 35.7+/-5.9 vs. 40.6+/-12.7 mm Hg; after 2 h, 41.5+/-10.7 vs. 46.3+/-15.2 mm Hg; for C1 INH and control animals, respectively). However, the RV could be loaded with a significantly higher volume after both 1 h (60.0+/-20.0 ml (C1 INH) vs. 46.7+/-13.7 ml (control) balloon volume, P<0.05), and 2 h of reperfusion (70.0+/-8.9 ml vs. 60.0+/-6.3 ml; C1 INH and control animals, respectively; P<0.05). CONCLUSIONS: Intracoronary administration of a C1 INH significantly improves right ventricular function in an experimental transplant model. Thus, inhibition of the classic complement cascade may be a promising therapeutic approach for effective protection of myocardium from reperfusion injury after transplantation.

Animals↗
PubMed1998

A new minimally invasive approach to the subclavian artery.

Aneurysms of the subclavian artery are rare. We report a case in which an aneurysm of the right subclavian artery presented as localized atrophy of the deltoid muscle. Operative repair was accomplished by a new minimally invasive surgical approach.

Adult↗
PubMed1998

Aortic homografts versus mechanical valves in aortic valve replacement in young patients: a retrospective study.

BACKGROUND: Whether aortic homografts (AH) or mechanical devices (MD) are the valves of choice for aortic valve replacement in young patients (age 20 to 50 years) is unclear. Hence, we examined all aortic valve replacements performed with AH and MD in a retrospective study. METHODS: Between 1988 and 1995, 45 patients (mean age, 38.6+/-8.5 years) underwent aortic valve replacement with an AH and 40 patients (mean age, 42.0+/-7.2 years) with an MD. Patients' demographic data were comparable in all respects, except acute endocarditis, which was an absolute indication for the use of an AH. RESULTS: The mean follow-up time was 51.7+/-22.6 months for AH versus 44.6+/-26.9 months for MD (not significant). There were significant differences in postoperative outcome among the two groups (p < or = 0.05): perioperative death (4 versus 0 for AH and MD, respectively); reoperation (8 for AH versus 0 for MD); and endocarditis (5 versus 0 for AH and MD). There were higher incidences of embolism (2 versus 0) and hemorrhage (2 versus 0) in MD compared with AH. Only late death was comparable among the two groups with 5 patients in each group. CONCLUSIONS: The mechanical valves in our midterm follow-up are superior to homografts. However, embolic and hemorrhagic complications in MD are continuously impending and cumulative during a long-term follow-up. The surprisingly high rate of endocarditis in the AH group is only partly caused by the indication: 2 cases were recurrent, but there were also 2 new onsets of endocarditis. In 4 cases structural deterioration was responsible for reoperation. Aortic valve replacement with aortic homografts showed a rather unfavorable midterm outcome in this selected group of young patients. A surprisingly high rate of graft endocarditis and structural deterioration led to subsequent reoperations. Although our results with mechanical valves are satisfying, embolism and hemorrhage are impending risk factors for many years to come in these young patients.

Adult↗
PubMed1998

Contribution of the interventricular septum to maximal right ventricular function.

OBJECTIVE: Maximal right ventricular (RV) function is influenced by left heart hemodynamics, possibly mediated by the interventricular scpturn (IVS). We examined the potential contribution of the IVS function to right heart function. METHODS: In 12 canine isovolumic right heart preparations, incremental volumes were introduced into a high compliance RV balloon until RV failure occurred. Maximal RV developed pressure (RVDP) and maximal positive RV dP/dt were determined with a working IVS at a constant left ventricular (LV) output of 2 l/min and at a constant mean arterial pressure of 80 mmHg. Thereafter the IVS was thermally inactivated, and measurements were repeated using the same protocol. RESULTS: At constant arterial pressure and constant LV output, thermal inactivation of the IVS led to a significant decrease in maximal RVDP (inactivated vs. working IVS: 36.1+/-9.8 vs. 56.8+/-16.2 mmHg, respectively, P < 0.001), and RV dP/dt (inactivated vs. working IVS: 720+/-220 vs. 1350+/-190 mmHg/s, respectively, P < 0.001). CONCLUSIONS: These results suggest that the functional status of the IVS is a major determinant of maximal RV function. At constant LV conditions and arterial pressure, an inactivated IVS leads to a significant decrease in maximal RVDP and RV dP/dt under the conditions of this study.

Animals↗
PubMed1997

A new, biventricular working heterotopic heart transplant model: anatomic and physiologic considerations.

BACKGROUND: Current heterotopic heart transplant models have nonworking left ventricles that atrophy and are not suitable for some studies. We developed and characterized a new heterotopic model with working left and right ventricles. METHODS: Hemodynamics were compared in the working and nonworking models. The influence of the length of the donor's aorta on coronary arterial oxygenation was tested. The influence of the recipient's arterial pressure on developed left ventricular systolic pressure and the effects of alpha- and beta-adrenergic stimulation were examined in both models. The nonworking and working models were compared in chronic transplant preparations to investigate possible ventricular atrophy. RESULTS: In this model, coronary arterial oxygen tension was influenced by the length of the donor's aorta. With a short donor aorta (0.5 cm in the porcine model), normal coronary arterial oxygenation is maintained. Left ventricular systolic pressure was greater in the working compared with the nonworking models. Left ventricular systolic pressure did not respond to alpha-adrenergic stimulation but did respond to beta-adrenergic and combined stimulation, which indicates its relationship to donor heart output. Left ventricular systolic pressure correlated with and was determined by recipient arterial pressure. Ventricular atrophy occurred in the nonworking model, but ventricular weight was maintained at sham control levels in this new working model. CONCLUSION: These results demonstrate the surgical anatomic considerations of a new heterotopic heart transplant model in which the left and right ventricles work. Its hemodynamic performance is related to recipient hemodynamics, and the model responds to adrenergic stimulation. In chronic studies, ventricular mass is maintained, thus allowing this model to overcome a significant shortcoming of existing heterotopic heart transplant models.

Animals↗
PubMed1997

The pulmonary homograft as aortic valve substitute: 7 years' follow up.

OBJECTIVE: The advantages of the aortic valve homograft high resistance to infective endocarditis, low risk of thromboembolism, low gradient and excellent long term results are well known. Trying to extend these advantages to a greater number of patients, we used pulmonary homografts as aortic valve substitute, based on the experimental evidence, that they can withstand the higher stress in systemic circulation. METHODS: From September 1988 to August 1994 175 patients (103 men, 72 women, mean age 61.75 +/- 12.92 years) underwent aortic valve replacement with a cryopreserved pulmonary homograft. All valves were taken from our own homograft bank. They were inserted freehand intraaortically, 162 in subcoronary position, 13 as intraaortic cylinder. All patients were followed clinically and by colorflow Doppler echocardiography in 3-12 month intervals. RESULTS: Patients, 8, died perioperatively (4.57%). None of the deaths was valve related. Patients, 2, had to be reoperated during the perioperative period due to severe valvular incompetence 165 patients were followed up to a period of 7.5 years (mean interval 3.83 +/- 1.45 years). Patients, 30, died, 13 deaths (7.42%) must be regarded as valve related. Patients, 22, (12.52%) had to be reoperated due to severe graft incompetence. Patients, 9 (5.14%), acquired prosthetic endocarditis. CONCLUSION: Due to our results, high rate of valve related deaths, high rate of graft failure and high rate of prosthetic endocarditis, we must state that the pulmonary homograft did not fulfil our expectations and presently we can not recommend it as an aortic valve substitute.

Aortic Valve↗
PubMed1997

Influence of case scheduling on outcome in cardiac surgery.

OBJECTIVE: Whether scheduling of patients for cardiac surgery as dictated by the availability of cardiopulmonary machines (CPBM) may influence postsurgical outcome, thought not to be an issue in the past, is unknown. EXPERIMENTAL DESIGN AND SETTING: Cardiac surgical outcomes were compared between two consecutive 12 months intervals surrounding the acquisition of a second CPBM by our department in a general hospital. PATIENTS: Patients in Group A (n=416) underwent surgery when only 1 CPBM was available (February 1990-January 1991) and in Group B (n=603) when 2 CPBM were used (February 1991 to January 1992). A cohort, Group C, consisted of patients (n=73), found only in Group A, scheduled as a 3rd and 4th operative case in the same day. RESULTS: There were no significant differences in demographic and clinical characteristics, the duration of ICU stay or hospital discharge between groups A and B. The surgical or technical staff did not change, and the nurse to patient ratio remained constant. Median total bypass time was significantly greater in Group B (80 vs 73 min in Group A, p<0.05), but the frequency of mortality within the first 14 postoperative days was nevertheless lower in Group B than in Group A (3.3% vs 4.6%, respectively, p<0.05). Recurrent myocardial infarction, postoperative bleeding, arrhythmia, pulmonary embolism, acute renal failure, and duodenal ulcer were also significantly higher in Group A compared to Group B (p<0.05). The excess in postoperative complications could be attributed mainly to Group C. Overall, the relative risk for morbidity and mortality decreased when a second CPBM was implemented (p<0.001). CONCLUSIONS. Postoperative complications in our unit were significantly reduced by acquisition of a second CPBM permitting two cases to be started concomitantly early in the day. This data may be valuable to guide decision analysis in departments which need to expand resources in order to cope with the demand of expanding clinical case load.

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