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G Ziemer

Publications and source records attributed to G Ziemer.

At least 19 recordsLinked to original sources
PubMed2006

[Echocardiographic diagnosis of the aorto-pulmonary window].

UNLABELLED: PURPOSE/MATERIALS AND METHODS: The aorto-pulmonary window is a rare congenital cardiac malformation consisting of a connection between the ascending aorta and the main pulmonary artery. Based on 5 consecutive patients who were treated in our tertiary referral centre between 7/2000 and 11/2005, we report the echocardiographic features as well the limitations of this diagnostic method in the assessment of this rare malformation. RESULTS: Dilation of the left atrium and ventricle due to the large left-to-right-shunt was the characteristic echocardiographic feature in all patients with aorto-pulmonary window. In all patients we were able to visualise the window by 2D-echocardiography. Pulsed- and continuous-wave Doppler showed diastolic negative flow in the descending aorta and in systemic arteries due to left-to-right shunting in diastole via the aorto-pulmonary window. All 5 patients had significant associated cardiovascular malformations. They were accurately diagnosed by echocardiography. Coronary anomalies could be excluded noninvasively in all patients. CONCLUSION: Echocardiography is the method of choice for diagnosis of aortopulmonary window. Detection of aortopulmonary window, however, requires a systematic and careful investigation of all cardiovascular anatomic details, since this anomaly is frequently associated with substantial additional cardiac anomalies, which would by themselves be sufficient to explain the haemodynamic abnormalities of the patient. Cardiac catheterisation is required only in cases with inadequate information about coronary artery anatomy or in older patients with pulmonary hypertension, to determine the patient's suitability for surgical correction.

Aorta, Thoracic↗
PubMed2006

Tirofiban (Aggrastat) protects platelets and decreases platelet-granulocyte binding in an extracorporeal circulation model.

OBJECTIVES: Extracorporeal circulation (ECC) induces platelet activation and inflammation with potentially life-threatening organ dysfunction. Short-acting GP IIb/IIIa inhibitors like tirofiban and eptifibatide protect platelets during ECC without increasing bleeding complications and may reduce inflammation. This study investigates anti-thrombotic and anti-inflammatory effects of different platelet inhibitors. METHODS: Control (untreated) and treated (using either 150 ng/mL tirofiban, 2.5 microg/mL eptifibatide, 0.7 microg/mL milrinone, 15 microg/mL dipyridamol, or 300 KIU/mL aprotinin) heparinized blood of healthy volunteers (n = 6) was recirculated in a well-established ECC model (Chandler loop). Percentage of platelet aggregates, P-selectin-expressing (activated) platelets, CD15-positive aggregates (indicating proinflammatory platelet-granulocyte binding), and platelet counts were determined before (baseline) and after 30 minutes recirculation in unstimulated and ADP-stimulated samples using flow cytometry. Statistical analysis was performed using multifactor ANOVA after transforming the data (logarithms for counts and log odds for percentages). Least square means were backtransformed to obtain appropriate means and their 95 % confidence intervals. Multiple post-hoc comparisons were performed by Tukey's HSD test with a global alpha of 5 %. RESULTS: Significant inhibition was observed for: 1) ECC-induced platelet aggregation by tirofiban (unstimulated: 2.2-fold/stimulated: 2.46-fold), eptifibatide (unstimulated: 1.96-fold/stimulated: 2.65-fold), and milrinone (unstimulated: 1.87-fold/stimulated: 1.37-fold); 2) ECC-induced P-selectin expression by tirofiban (unstimulated: 3.95-fold/stimulated: 2.54-fold), and eptifibatide (unstimulated: 5.87-fold/stimulated: 3.28-fold); 3) ECC-induced platelet loss by tirofiban (1.27-fold), and eptifibatide (1.25-fold); 4) ECC-induced platelet-granulocyte binding by tirofiban (unstimulated: 2.25-fold/stimulated: 1.59-fold), but not by eptifibatide. CONCLUSIONS: Amongst the investigated drugs only GP IIb/IIIa inhibitors decreased activation, aggregation, and loss of platelets during ECC but acted differently on platelet-granulocyte interaction. A short-acting GP IIb/IIIa inhibitor with the potential to inhibit platelet activation and platelet-leukocyte interaction should be considered both for platelet protection and inhibition of platelet-mediated inflammation during ECC.

Aprotinin↗
PubMed2006

Challenging the advanced: cardiac surgery without awareness of a pheochromocytoma.

We report the case of a 75-year-old male patient who underwent bypass surgery. Intraoperatively unstable hemodynamics with excessive arterial blood pressure was observed. This resulted in the tearing of an anastomosis, which subsequently required hemostasis for repeated bleeding. Postoperatively, laboratory findings and diagnostic imaging confirmed the diagnosis made intraoperatively of a pheochromocytoma. Any surgery without awareness of the possibility of a pheochromocytoma will dramatically increase intraoperative and postoperative morbidity and mortality, especially in cardiac surgery. The uncontrolled release of catecholamines raises arterial blood pressure which can become life-threatening and lead to serious intraoperative complications, as well as cerebrovascular and cardiac comorbidity.

Aged↗
PubMed2006

Incidental diagnosis of a left ventricular thrombus through novel magnetic resonance imaging technique in a patient undergoing coronary artery bypass grafting.

Stroke after cardiac surgery is a devastating complication. We report a case of incidental diagnosis of a left ventricular thrombus in a patient scheduled to undergo coronary artery bypass grafting. The preoperative diagnosis of an apical left ventricular thrombus was assessed by a novel, whole body MRI-angiography technique (TIMRA), which led to alteration of the operative approach as an additional thrombectomy was performed through an apical left ventriculotomy.

Coronary Artery Bypass↗
PubMed2005

Recanalisation of bilateral superior vena cava after total cavopulmonary connection. Interventional occlusion with the Amplatzer VSD Occluder.

UNLABELLED: Formation of systemic to pulmonary venous or systemic venous left atrial collaterals frequently occurs in patients after Glenn or Fontan-type operations. Embolization with detachable metal coils is the therapy of choice for the closure of small vessels. These devices however are not appropriate for the occlusion of large collaterals, e. g. recanalized bilateral caval veins. We report two patients who presented late after Fontan-type operations with a gradual decrease in oxygen saturation due to recanalisation of bilateral caval veins. Interventional closure of these large veins was carried out successfully with the use of 8 mm Amplatzer muscular VSD Occluders, resulting in an increase of arterial oxygen saturations. CONCLUSION: The closure of recanalized bilateral superior caval veins after Fontan procedures is possible without technical problems by means of the Amplatzer muscular VSD Occluder. In order to avoid future formation of venous collaterals via the azygos or hemiazgos system, the occluder should be placed in the vena cava below the orifice of the azygos/ hemiazygos vein.

Adult↗
PubMed2005

Hypothermia-induced platelet aggregation: no effect of aprotinin (trasylol) but inhibition by eptifibatide (integrilin).

OBJECTIVES: The serine-protease inhibitor aprotinin protects platelet function during cardiopulmonary bypass. However, its safety and efficacy during deep hypothermic circulatory arrest (DHCA) is controversial, and aprotinin is suspected to cause thrombosis especially during hypothermia. The platelet GP IIb/IIIa inhibitor eptifibatide has been assumed to preserve platelet function during cardiopulmonary bypass without increasing bleeding complications. The aim of this study was to compare the effect of aprotinin and eptifibatide on platelet function under conditions of DHCA. METHODS: Heparinized blood from healthy volunteers (n = 10) was incubated in stasis for 30 minutes at 18 degrees C to simulate DHCA and compared to samples incubated at 37 degrees C. The effect of eptifibatide (2.5 microg/ml) and aprotinin (300 KIU/ml) on platelets under these conditions was analyzed by flow cytometry. Platelet aggregates were identified using CD41-antibody binding and size. GPIIb/IIIa function was evaluated with the activation-specific antibody PAC-1 after stimulation with 10 microM ADP. Aggregate numbers and antibody mean-fluorescence are reported as mean +/- standard deviation. RESULTS: Hypothermia induced a 2.5-fold increase of aggregates ( p < 0.001) and a 2.6-fold increase of GPIIb/IIIa activation ( p < 0.001). This effect was not influenced by aprotinin but almost completely inhibited by eptifibatide ( p < 0.001). CONCLUSIONS: Aprotinin has no procoagulatory effect on platelet function during hypothermia but is not protective either. Eptifibatide inhibits hypothermia-induced platelet aggregation in vitro and may prevent aggregate sequestration in the microvasculature and consecutive ischemic organ damage in vivo.

Aprotinin↗
PubMed2005

Aortic root remodeling: functional MRI as an accurate tool for complete follow-up.

BACKGROUND: After aortic valve-sparing procedures patients should be evaluated regularly because of the risk for further disease progression in the remaining aorta as well as recurrent aortic insufficiency. The purpose of this study was to evaluate the potential of functional MRI as a single examination for complete follow-up of these patients. METHODS: Twenty-two patients with a mean age of 54 years (range 30 - 66) were prospectively examined at 1, 12, 24, 36, and 74 months postoperatively, following a Yacoub aortic root remodeling operation, using a 1.5 T MRI. The original disease was chronic aneurysm of the ascending aorta or root in 17, chronic dissection in 3, and acute dissection in 2 patients. Transverse graft diameters, regurgitant fraction, LVEDV, and cardiac index were measured using cine MRI. Results were compared to spiral computed tomography and transthoracic color Doppler echocardiography. Mean time of follow-up was 24.9 months and ranged from 1 to 74 months. RESULTS: There were 2 re-operations, 2 years after primary surgery, due to high aortic insufficiency. CT and MRI measurements of graft diameters correlated well (p = 0.4544). Mean graft diameter (mean +/- SD) was 30 +/- 3.7, 33 +/- 3.4, 36.5 +/- 1.5, 37 +/- 2.8, and 38.3 +/- 2.8 mm at 1, 12, 24, 36, and 74 months, respectively, indicating a significant increase of graft diameter (p < 0.0001). Mean regurgitant fraction as determined by MRI was 14 +/- 7, 12 +/- 9, 13 +/- 9, 15 +/- 7, and 14 +/- 9 % at 1, 12, 24, 36, and 74 months, respectively. Flow based grading of aortic insufficiency by MR imaging correlated well with color Doppler echocardiography (p < 0.0001). CONCLUSIONS: MRI provides an excellent, noninvasive, comprehensive tool for follow-up after valve-sparing aortic root reconstruction. The determination of regurgitant fraction, ventricular dimensions and functions, and graft diameters allows standardized imaging protocols with a high reproducibility, which may lead to this technique being favored for the follow-up of patients after aortic root remodeling.

Adult↗
PubMed2004

Brain natriuretic peptide (BNP) in patients undergoing coronary artery bypass grafting.

BACKGROUND: This study was designed to examine plasma concentrations of BNP and its relation to hemodynamic parameters in patients (pts.) with coronary artery disease (CAD) undergoing coronary artery bypass grafting (CABG). METHODS: 21 pts. with CAD undergoing CABG were examined. The pts. were divided into two groups. Group I: normal left ventricular function (LVF); Group II: reduced LVF. Pre-, intra- and postoperative BNP and hemodynamic parameters were measured. The perioperative administration of inotropic drugs was documented. RESULTS: In both groups postoperative BNP increased to a peak 24 h postoperatively; although BNP concentrations were high 24 h postoperatively hemodynamic parameters were improved in both groups. In Group I the BNP peak did not correlate with any hemodynamic parameter nor with the use of inotropic drugs. In Group II the BNP peak was inversely correlated with CO and CI and positively correlated with the PCWP. There was no correlation with inotropic support. CONCLUSION: Postoperative peak of BNP after 24 h does not reflect a state of acute perioperative heart failure or myocardial damage. These results suggest that the gene expression, metabolism and biological activity of BNP may be altered after extracorporeal circulation. Further studies are warranted to reveal the actual triggers for BNP increase early after CABG.

Aged↗
PubMed2004

Excision of the coronary orifices in arterial switch operation: "O" like obstructive and "U" like unobstructive?

BACKGROUND: Stenoses of the neo-pulmonary artery (NPA) may complicate follow-up of the arterial switch operation (ASO). It is unknown whether the type of patch covering the coronary excision defects ("O"- or "U"-shaped) might influence this complication. METHODS: Echocardiographically and invasively measured NPA pressure-gradients were evaluated retrospectively in 95 children after ASO. Median follow-up was 5.8 years. Defects had been covered with pericardial patches: O/O and U/U (left/right) 34 x each, and 27 x in mixed combinations. The frequency of NPA stenoses requiring re-interventions was registered. RESULTS: Median of the peak instantaneous echocardiographic pressure gradient was 23 mmHg (interquartile range, IQR: 16 - 49, n = 34) in O/O, and 19 mmHg (IQR: 13 - 23, n = 34) in U/U; p < 0.034, t-test. Invasively measured gradients were 49 mmHg (IQR: 17 - 65, n = 12) in O/O, and 12 mmHg (IQR: 7-21, n = 28) in U/U; p < 0.001. One child per O/O- and U/U-group underwent balloon angioplasty of the neo-pulmonary root. Five children of the O/O-group had to undergo repeat surgery, whereas only one child in the U/U-group required repeat surgery ( p < 0.34). CONCLUSIONS: The preferential type of covering the NPA coronary excision sites in ASO should be U-shaped.

Anastomosis, Surgical↗
PubMed2003

Isolated coronary artery rupture after blunt chest trauma.

After blunt chest trauma, a patient with chronic coronary heart disease sustained an isolated rupture of the right coronary artery. All findings suggested a heart contusion complicated by a non-compromising pericardial effusion and aggravated by anticoagulation with phenprocoumon. After right-ventricular failure occurred, emergency coronary revascularization could not prevent a fatal outcome. This case emphasizes that a coronary artery lesion may be considered in those cases of thoracic trauma with preexisting coronary calcification.

Aged↗
PubMed2003

[Echocardiographic diagnosis of the aorto-left ventricular tunnel].

AIM/METHOD: The aorto-left ventricular tunnel (ALVT) is a rare congenital cardiac malformation with clinical findings of severe aortic insufficiency. We report the echocardiographic differentiation of different anatomical variants of ALVT in two infants. RESULTS: Echocardiography in both patients demonstrated severe enlargement of the ascending aorta and the left ventricle. In the first patient the ALVT originated from the ascending aorta above the right coronary sinus and entered the left ventricle just below the aortic valve. In the second patient the ALVT originated above the left coronary sinus and took a lateral course to the left ventricle. Colour-Doppler-sonography in both patients confirmed a systolic-diastolic flow across the tunnel. Many patients have associated cardiac defects. Exact determination of the morphology of the aortic valve and coronary arteries is mandatory for surgical repair. Postoperative follow-up studies focus on the function of the aortic valve and the left ventricle. CONCLUSION: Differentiation of different anatomical variants of ALVT is possible trough echocardiography. Cardiac catheterization is required only in cases with inadequate information about coronary artery anatomy.

Aortic Valve↗
PubMed2002

[Tetralogy of Fallot with right pulmonary artery origin from the ascending aorta: noninvasive diagnosis and surgical correction in a 7-week-old infant].

Anomalous origin of one pulmonary artery from the ascending aorta is a rare anomaly which is almost always associated with hypertension in the contralateral pulmonary artery originating from the right ventricle. We report echocardiographic evaluation of an infant with tetralogy of Fallot and aortic origin of the right pulmonary artery. Since all relevant information regarding anatomy and hemodynamics could be obtained by echocardiography, cardiac catheterization and angiography were unnecessary. Surgical correction including transatrial patch closure of the ventricular septal defect, resection of the infundibular stenosis and direct reimplantation of the right pulmonary artery was performed successfully at the age of 7 weeks. The postoperative course was uneventful and persistent pulmonary hypertension was excluded by echocardiography. Our case shows that complete echocardiographic evaluation is possible in infants with this complex cardiac malformation. We recommend reserving cardiac catheterization for those patients with echocardiographic evidence of significant elevation of pulmonary vascular resistance. In order to avoid irreversible pulmonary vascular changes early surgical correction within the first 3 months of life should be performed in all children with aortic origin of a pulmonary artery including those with associated tetralogy of Fallot.

Aorta↗
PubMed2002

Successful repair of intraoperative type-A dissection in an infant.

A case of intraoperative type-A aortic dissection caused by partial displacement of the aortic cannula in a 6-month-old infant is presented, which was successfully managed by reapproximation of the dissected layers of the ascending aorta. At 1 year of follow-up the imaging studies show a normal appearance of the operation site.

Aorta↗
PubMed2002

Value of positron emission tomography for lung cancer staging.

OBJECTIVE: The therapeutic strategy in non-small-cell lung cancer (NSCLC) requires exact staging of tumour invasion (T) as well as differentiation between ipsi- and contralateral lymph node invasion (N1/2 vs N3). [18F]FDG-positron emission tomography (FDG-PET) has been shown to detect invaded N with high accuracy while correct determination of T appears to be unclear. The purpose of this prospective study was to evaluate benefit and necessity of 18FDG-PET as an additive to conventional staging modalities. METHODS: Forty patients with suspected non-small-cell lung cancer (NSCLC) were staged by means of computed tomography (CT), bronchoscopy, mediastinoscopy and bone scintigraphy. Additionally, attenuation corrected FDG-PET of the thorax was performed pre-operatively for analysis of T and N topography. After surgical resection with radical lymphadenectomy T and N staging results of CT and PET were compared with the pathological diagnoses. Specificity, sensitivity, positive predictive value and accuracy of CT and PET were calculated. RESULTS: Twenty three squamous cell carcinomas, 14 adenocarcinomas, and three non-malignant tumours were found. Accuracy of CT-T was 0.75 and of PET-T 0.78; accuracy of CT-N was 0.78 and of PET-N 0.80. By combination of CT-T and PET-T accuracy was 0.88. Combination of CT-N and PET-N yielded an accuracy of 0.90. In two out of three cases, PET correctly determined T0. In two cases non-malignant inflammatory lymph nodes were falsely staged as malignant by PET. CONCLUSIONS: Adequate pre-operative T- and N-staging is possible with both CT and FDG-PET. Accuracy can be improved by combination of CT and FDG-PET. FDG-PET is superior to CT in order to differentiate between malignant and benign tumours. However, acute inflammation can mimic malignant lymph node invasion. FDG-PET is justified as a supporting staging measure in cases presenting unclear differentiation between N2 and N3 after conventional staging and is helpful in cases with unclear cell type of the primary tumour.

Carcinoma, Non-Small-Cell Lung↗
PubMed2002

[Endovascular implantation of stent-grafts in the thoracic aorta -mid-term results of a prospective controlled study].

PURPOSE: To evaluate the effectiveness and safety of endovascular treatment of various descending thoracic aortic pathologies with covered stent-grafts as an alternative to open surgery. METHODS: Among 16 patients (5 type B dissections, 5 contained ruptures, 3 aneurysms of the descending aorta, 1 thoraco-abdominal aneurysm, 1 mural thrombosis, 1 patch aneurysm) treated between November 1997 and November 2000, eight patients received Talent stent-grafts and another 8 patients underwent a Gore-TAG stent-graft implantation. A clinical follow-up and control CT scans were obtained after the procedure and then at six-month intervals. RESULTS: Deployment of the stent-grafts was technically successful in all cases. Sufficient aortic reconstruction was achieved in all but one patient who needed surgical treatment. One patient died two days after the procedure from aortic rupture due to retrograde type A dissection. Another patient died 19 months after the procedure from an unknown cause. There was no occurrence of distal embolization, paralysis or infection. During follow-up, all patients remained free from recurrence or late complications of their disease. CONCLUSION: Endoluminal treatment of thoracic aortic pathologies with covered stent-grafts appears to be a safe and feasible method with at least mid-term efficacy.

Adult↗
PubMed2002

Right-sided cervical aortic arch with stenosis--treatment with an extra-anatomic bypass graft.

Right-sided cervical aortic arch is a very rare vascular anomaly that may lead to stenosis development. Anatomic repair may be impeded by its high course or by abnormal branching of the supraaortic vessels, or both. This report will describe the treatment of a stenotic right-sided cervical aortic arch using an extra-anatomic bypass graft without extracorporeal support in an 11-year-old girl.

Aorta, Thoracic↗
PubMed2001

Gene monitoring of surface-activated monocytes in circulating whole blood using duplex RT-PCR.

Previous studies have shown that blood-contacting materials activate blood monocytes. The aim of this study is to evaluate a highly sensitive technique for detecting changes at the mRNA level in circulating monocytes and to find suitable "gene markers" for assessing the hemocompatibility of biomaterials. Human blood was recirculated in a modified Chandler Loop formed of test tubes. Five groups of biomaterials were compared. Monocytes were separated by using magnetic beads, and gene expression analyses were performed using RT-PCR. We investigated the mRNA expression of stress proteins (hsp70) and inflammatory markers (IL-1alpha, IL-1beta, IL-6, TNF-alpha). mRNAs for cytokines were highly upregulated in LPS-stimulated monocytes. Hsp70 transcripts were upregulated after heat shock but were not influenced by treatment with LPS. The gene expression of the cytokines was affected by various biomaterials. The intensity of the inflammatory response increased in the following order: heparin coatings (PVC) < uncoated PVC < silicone, polypeptide-coated PVC. No change was seen in the expression of the hsp70 genes. An inhibitory effect of systemic heparin on surface-activated monocytes was observed for the mRNA expression of the cytokines. The recirculation of human blood in an in vitro model in combination with the immunomagnetic separation of monocytes and the Duplex RT-PCR method is a powerful tool for getting reliable results. Our data demonstrate that hsp70 genes cannot be recommended for short-term, biomaterial-induced mRNA expression studies. Conversely, mRNAs for IL-1alpha, IL-1beta, IL-6, and TNF-alpha were expressed in a material-dependent manner. Thus our model provides an effective tool for assessing the hemocompatibility of biomaterials before their clinical application and it also can serve as a safety control during the industrial manufacturing process. This method can be applied to various blood cell populations and numerous gene expression studies and may enable a more fundamental understanding of the biologic processes involved in blood-material interactions.

Biocompatible Materials↗