Biomedical subjects

Bernfried Zickmann

Publications and source records attributed to Bernfried Zickmann.

10 recordsLinked to original sources

PubMed2006

Percutaneous implantation of the CoreValve self-expanding valve prosthesis in high-risk patients with aortic valve disease: the Siegburg first-in-man study.

BACKGROUND: The morbidity and mortality of surgical aortic valve replacement are increased in elderly patients with multiple high-risk comorbid conditions. Therefore, a prospective, single-center, nonrandomized study was performed in high-risk patients with aortic valve disease to evaluate the feasibility and safety of percutaneous implantation of a novel self-expanding aortic valve bioprosthesis (CoreValve). METHODS AND RESULTS: Symptomatic high-risk patients with an aortic valve area <1 cm2 were considered for enrollment. CoreValve implantation was performed under general anesthesia with extracorporeal support using the retrograde approach. Clinical follow-up and transthoracic echocardiography were performed after the procedure and at days 15 and 30 after device implantation to evaluate short-term patient and device outcomes. A total of 25 patients with symptomatic aortic valve stenosis (mean gradient before implantation, 44.2+/-10.8 mm Hg) and multiple comorbidities (median logistic EuroScore, 11.0%) were enrolled. Device success and procedural success were achieved in 22 (88%) and 21 (84%) patients, respectively. Successful device implantation resulted in a marked reduction in the aortic valve gradients (mean gradient after implantation, 12.4+/-3.0 mm Hg; P<0.0001). The mean aortic regurgitation grade was unchanged. Major in-hospital cardiovascular and cerebral events occurred in 8 patients (32%), including mortality in 5 patients (20%). Among 18 patients with device success surviving to discharge, no adverse events occurred within 30 days after leaving the hospital. CONCLUSIONS: Percutaneous implantation of the self-expanding CoreValve aortic valve prosthesis in high-risk patients with aortic stenosis with or without aortic regurgitation is feasible and, when successful, results in marked hemodynamic and clinical improvement.

Aged↗

PubMed2005

First report on a human percutaneous transluminal implantation of a self-expanding valve prosthesis for interventional treatment of aortic valve stenosis.

BACKGROUND: Percutaneous aortic valve replacement is a new technology for the treatment of patients with significant aortic valve stenosis. We present the first report on a human implantation of a self-expanding aortic valve prosthesis, which is composed of three bovine pericardial leaflets inserted within a self-expanding nitinol stent. The 73-year-old woman presented with severe symptomatic aortic valve stenosis (mean transvalvular gradient of 45 mmHg; valve area of 0.7 cm2). Surgical valve replacement had been declined for the patient because of comorbidities, including previous bypass surgery. METHOD AND RESULTS: A retrograde approach via the common iliac artery was used for valve deployment. The contralateral femoral vessels were used for a temporary extracorporal circulation, unloading the left ventricle during the actual stent expansion. Clinical, hemodynamic, and echocardiographic outcomes were assessed serially during the procedure. Clinical and echocardiographic follow-up at day 1, 2, and 14 post procedure was performed to evaluate the short-term outcome. The prosthesis was successfully deployed within the native aortic valve, with accurate and stable positioning and with no impairment of the coronary artery or vein graft blood flow. 2D and doppler echo immediately after device deployment showed a significant reduction in transaortic mean pressure gradient (from 45 to 8 mmHg) without evidence of aortic or mitral valve insufficiency. The clinical status has then significantly improved. These results remained unchanged up to the day 14 follow-up. CONCLUSION: This case report demonstrates a successful percutaneous implantation of a self-expanding aortic valve prosthesis with remarkable functional and clinical improvements in the acute and short-term outcome.

Aged↗

PubMed2004

Perioperative management in pediatric heart transplantation from 1988 to 2001: anesthetic experience in a single center.

Pediatric cardiac transplantation is currently an accepted option for end-stage heart disease and congenital cardiac malformations. This report focuses on the anesthetic perioperative management in 12 yr. From 1988 to 2001 we performed 90 heart transplantations in 88 children, infants and neonates. The pediatric heart transplant program of the children's heart center at our university hospital started in June 1988 with the transplantation of a 2-yr-old boy who was suffering from congenital heart disease. Since then, 88 transplants have been performed. We divided our patients into two groups. Group 1 ranged from 1988 to 1996 and Group 2 from 1997 to 2001. The patient characteristics have not significantly changed over the years in our institution. At the time of transplantation, mean age of the patients was 2.6 +/- 4.3 yr from the period of 1988-1996 and 2.5 +/- 4.1 yr from 1997 to 2001. Since 1988, 90 transplants (Tx) in 88 patients have been performed. Two patients needed re-Tx within 2 days after the initial operation because of primary graft failure. Indications for Tx were congenital heart disease (n = 67) and cardiomyopathy (n = 21). In the subgroup of the patients suffering from congenital heart disease there were 46 with the diagnosis of HLHS, followed by endocardial fibroelastosis (n = 7); the remaining 14 patients had other complex cardiac malformations and some underwent corrective palliative cardiac surgery before Tx. Sixty-three patients were younger than 1 yr of age and only five children were older than 10 yr. Twenty-three percent of the patients on the waiting list died before Tx was possible. The overall survival rate was 79% at 1 yr and 73% at 5 and 10 yr. Infants with HLHS had a lower probability of survival after 5 yr compared with other diagnosis (69% vs. 84%). Until now 21 patients have died after Tx. The duration of anesthesia, time of CPB and the age at the time of surgery decreased over the years. It is always a challenge for the anesthesiologist to treat these patients with pulmonary hypertension as one of the most critical risks in this group of patients. The preventive therapy with vasodilators as well as the availability of mechanical assist devices before and after heart transplantation reduces the effects of transitional pulmonary hypertension and prevents the development of post-operative right heart failure.

Anesthesia↗

PubMed2003

Bradykinin and histamine generation with generalized enhancement of microvascular permeability in neonates, infants, and children undergoing cardiopulmonary bypass surgery.

OBJECTIVE: To investigate whether generation and liberation of bradykinin and histamine contribute to generalized edema formation in pediatric cardiopulmonary bypass surgery. DESIGN: Prospective observational study. SETTING: Pediatric heart surgery of a university hospital. PATIENTS: Forty-one neonates, infants, and children undergoing cardiopulmonary bypass to correct congenital cardiac anomalies. INTERVENTIONS: Plasma concentrations of bradykinin and histamine were determined before, during, and after cardiopulmonary bypass. Fluid balance was evaluated by control of fluid intake and output. MEASUREMENTS AND MAIN RESULTS: The susceptibility to generalized edema formation increased significantly (r = -.457; p <.005) with decreasing age. Approximately three times higher plasma concentrations of bradykinin (p <.001) were found at the onset of anesthesia and during the total observation period in patients with a fluid retention of >6% of body weight compared with patients with a lower retention rate. Plasma bradykinin reached significantly (p <.01) higher peak concentrations of 237.9 +/- 58.6 fmol/mL during cardiopulmonary bypass and of 227.5 +/- 90.7 fmol/mL during the early postoperative period in patients with severe edema formation in contrast to only 86.6 +/- 10.9 and 65.5 +/- 26.8 fmol/mL in patients with minor fluid retention. A tendency (p =.06) to slightly increasing histamine concentrations from 2.07 +/- 0.13 nmol/L at baseline to 3.32 +/- 1.41 nmol/L during 90 mins of cardiopulmonary bypass was only observed in patients with high fluid retention. CONCLUSIONS: Bradykinin seems to be essentially involved in the enhancement of microvascular permeability in pediatric cardiopulmonary bypass surgery, although a dominant causal role cannot be claimed by this study. Histamine, however, doesn't appear to play a major role and may only contribute as a cofactor. To what extent an increased expression of bradykinin-1 and bradykinin-2 receptors or a reduced potential of bradykinin-degrading enzymes is involved is the object of a further clinical study.

Adult↗

PubMed1996

Changes in heart rate variability during induction of anesthesia with fentanyl and midazolam.

OBJECTIVE: The study was designed to evaluate changes in autonomic nervous system function during induction of anesthesia with fentanyl, midazolam, and pancuronium and to answer the question of dose-dependency of these effects. DESIGN: Prospective, randomized. SETTING: A university hospital. PARTICIPANTS: Forty consecutive cardiac surgical patients. INTERVENTIONS: Anesthesia was induced with fentanyl, midazolam, and pancuronium. The patients were assigned to four groups differing in dosages of fentanyl plus midazolam and speed of injection. Fentanyl, 7.5 micrograms/kg (group A), 12.5 micrograms/kg (group B), and 20.0 micrograms/kg (group C) plus midazolam, 0.075 mg/kg (group A), 0.125 mg/kg (group B), and 0.200 mg/kg (group C) were administered over 10 minutes; in group D, fentanyl, 7.5 micrograms/kg, and midazolam, 0.075 mg/kg, were administered within 1 minute. MEASUREMENTS AND MAIN RESULTS: Heart rate variability (HRV) was measured using parameters in the time domain and the frequency domain. The comparison of preinduction HRV with the intra-anesthetic epochs did not show significant differences with respect to heart rate, coefficient of variation, and root mean squared successive differences. Spectral analysis showed significant reductions of power in the vasomotor band (0.01 to 0.05 Hz) and the low-frequency band (0.05 to 0.15 Hz) in all groups. Power in the high-frequency band (0.15 to 0.50 Hz) decreased slightly, but this did not reach the significance level. A dose dependency of these changes was found in the low-frequency band only. CONCLUSIONS: Parameters of HRV suggest that induction with fentanyl, midazolam, and pancuronium decreases sympathetic but not parasympathetic autonomic system activity. The anesthetic induction technique's modulation of autonomic nervous system balance is better represented by means of spectral analysis than by analysis in the time domain. This modulation was largely independent of the doses administered and independent of the speed of injection.

Adult↗

PubMed1993

RETRACTED: Influence of acute preoperative plasmapheresis on platelet function in cardiac surgery.

Withdrawal of autologous plasma offers the possibility of improving patients' hemostasis and of reducing homologous blood consumption in cardiac surgery. The influence of acute, preoperatively performed plasmapheresis (APP) on platelet function was investigated in elective aortocoronary bypass patients subjected to APP producing either platelet-poor plasma (PPP; group 1; n = 12) or platelet-rich plasma (PRP; group 2; n = 12). APP-treated patients were randomly compared to patients without APP (control group; n = 12). Platelet aggregation induced by ADP (concentration 0.25, 0.5, 1.0, and 2.0 mumol/L), collagen (4 microL/mL), and epinephrine (25 mumol/L) was determined by the turbidometric method before and after APP, as well as before and after cardiopulmonary bypass (CPB) until the morning of the 1st postoperative day. APP had no negative effects on the patients' aggregation parameters (maximum aggregation and maximum gradient of aggregation). The platelet counts in the withdrawn plasma were 25 +/- 10 x 10(9)/L (PPP-group) and 250 +/- 30 x 10(9)/L (PRP-group). Platelet counts were highest in the PRP-group at the end of the operation (after retransfusion of autologous plasma). After CPB, maximum aggregation and maximum gradient of aggregation were reduced in all groups (ranging from -6% to -25% from baseline values). Retransfusion of autologous plasma improved platelet aggregability significantly only in the PRP-group. By the first postoperative day, maximum aggregation and maximum gradient of aggregation recovered in all groups (including the control group) or even exceeded baseline values (ranging from +8% to +42% from baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Coagulation Tests↗

PubMed1992

RETRACTED: Right ventricular function in patients with reduced left ventricular function undergoing myocardial revascularization.

Complex interrelationships exist between the right (RV) and the left ventricles (LV). Therefore, in 30 consecutive patients with reduced LV function (left ventricular ejection fraction [LVEF]) less than 40% undergoing myocardial revascularization, RV hemodynamics were studied from the beginning of anesthesia until the end of the operation. The data were compared with 30 consecutive patients with normal LVEF (greater than 70%). Ventricular function was assessed during left heart catheterization, which was carried out within 1 month of the operation. In addition to standard hemodynamic variables, RV ejection fraction (RVEF), RV end-diastolic volume (RVEDV), and RV end-systolic volume (RVESV) were monitored by the thermodilution technique. The two groups did not differ preoperatively with regard to RVEF, pressure (MAP, PAP, PCWP, RAP, RVPsyst, RVEDP), cardiac index (CI), and volume variables (RVESV, RVEDV). However, when the group with preoperatively reduced LVEF was subdivided into patients with severely reduced LVEF (less than 30%; n = 14; mean value 25.1%) and patients with moderately reduced LVEF (30%-40%; n = 16; mean value 37.3%), RVEF was significantly lower in the patients with a LVEF below 30% throughout the entire investigation period. RVEDV and RVESV were significantly higher in these patients. In conjunction with the lower RVEF and normal PAP, this suggests reduced RV function. It can be concluded that a severely reduced preoperative LVEF (less than 30%) may also be associated with impaired RV function.

Analysis of Variance↗

PubMed1992

RETRACTED: Age and right ventricular function during cardiac surgery.

Elderly patients undergoing cardiac surgery are reported to be at a higher risk for circulatory failure than younger patients, most likely because of ventricular decompensation. To assess the role of the right heart in these patients, right ventricular (RV) hemodynamics in 40 consecutive elderly patients (greater than 70 years; mean = 77.1 +/- 3.4 years) were compared with 40 consecutive younger patients (50 to 60 years; mean = 55.2 +/- 3.0 years) undergoing elective coronary artery bypass surgery. In addition to standard hemodynamic variables, RV ejection fraction (RVEF) and RV end-systolic and end-diastolic volumes (RVESV, RVEDV) were studied perioperatively using a thermodilution technique. None of the elderly patients died in the perioperative period. The course of RV function was comparable in both groups during the entire investigation period, but the absolute values of RVEF before the onset of cardiopulmonary bypass (CPB) were significantly higher in the younger patients (48.0 +/- 4.4%) than in the older patients (38.9 +/- 4.6%). RVEDV and RVESV were always higher in the older patients in the pre-bypass period than in the control group. None of the other hemodynamic parameters showed significant differences between the groups. Analysis of covariance showed no correlation between RV volume and pressure parameters. Inotropic support during and after termination of CPB was necessary more often in the older (epinephrine, 6.7 +/- 2.0 micrograms/min) than in the younger patients (epinephrine, 4.4 +/- 2.2 micrograms/min). It is concluded that older patients undergoing myocardial revascularization can have excellent results. However, they may be predisposed to right heart complications because of their reduced RV function.

Aged↗

PubMed1992

RETRACTED: Right ventricular function in patients with aortic stenosis undergoing aortic valve replacement.

The effects of aortic stenosis (AS) on right ventricular function during cardiac surgery are not fully understood. Forty patients undergoing aortic valve replacement with either a systolic transvalvular gradient of less than 100 mm Hg (82.1 +/- 5.5 mm Hg; group 1, n = 20) or greater than 120 mm Hg (131.1 +/- 6.9 mm Hg, group 2, n = 20) were investigated with regard to right ventricular function in the perioperative period. Right ventricular ejection fraction (RVEF), right ventricular end-systolic volume (RVESV), and right ventricular end-diastolic volume (RVEDV) were measured by means of the thermodilution technique. Before cardiopulmonary bypass (CPB), RVEF was significantly lower in group 2 patients (34% +/- 6%) than in group 1 (45% +/- 5%). After CPB, RVEF increased significantly in group 2 (28% +/- 4% to 49% +/- 5%), and no further differences were noted between the groups. In the patients with a higher systolic transvalvular gradient, RVEDV and RVESV were lower at the start of surgery, but increased after opening the pericardium. Cardiac index was also lower in these patients. Pericardiotomy resulted in a decrease in right ventricular end-systolic pressure (RVESP) only in the patients of group 2. In these patients more epinephrine was necessary to maintain stable hemodynamics during the post-bypass period. It is concluded that patients with AS are at risk of reduced right ventricular function when the systolic transvalvular pressure gradient is more than 120 mmHg. Knowledge of the complex interaction between the two sides of the heart may enable anesthesiologists to optimize management during the perioperative period.

Aged↗

PubMed1991

RETRACTED: Acute preoperative hemodilution in cardiac surgery: volume replacement with a hypertonic saline-hydroxyethyl starch solution.

Preoperative hemodilution (HD) is a recommended practice in cardiac surgery that conserves blood and reduces the complications of homologous blood transfusion. In 45 patients undergoing myocardial revascularization, HD was performed preoperatively. Withdrawn volume (10 mL/kg) was replaced either by a new hypertonic saline (HS) solution prepared in hydroxyethyl starch (HES) (2,400 mOsm/L, HS-HES group, n = 15) or by a standard low molecular weight hydroxyethyl starch solution (6% HES 200/0.5, HES group, n = 15) to maintain baseline PCWP (acute normovolemic hemodilution [ANH]). Fifteen comparable patients without HD served as controls. Significantly less HS-HES (210 +/- 20 mL) than HES 6% (890 +/- 90 mL) was necessary to sustain hemodynamics during HD. Stable cardiocirculatory conditions were obtained even after termination of bypass. Fluid balance during cardiopulmonary bypass as well as in the postoperative period was significantly lower in HS-HES-treated patients. With regard to hemodynamics, CI increased most in the HS-HES group (+36%), whereas systemic vascular resistance was lower in these patients. Right ventricular ejection fraction increased only in HS-HES patients (+15%). However, sodium concentration as well as osmolarity increased after volume replacement with HS-HES, without exceeding normal values. None of the patients suffered from organ failure. Pulmonary gas exchange (PaO2) was less compromised in the HS-HES patients. There were no renal function differences between the groups. In conclusion, HS solution prepared in HES is an attractive alternative for blood substitution in cardiac patients undergoing acute hemodilution for blood conservation.

Atrial Function, Right↗