Biomedical subjects

Axel Haverich

Publications and source records attributed to Axel Haverich.

At least 37 records · Page 2Linked to original sources

PubMed2003

Role of inflammation in allogeneic and xenogeneic heart valve degeneration: immunohistochemical evaluation of inflammatory endothelial cell activation.

BACKGROUND AND AIM OF THE STUDY: Biological heart valve prostheses undergo degenerative changes which lead ultimately to dysfunction or even complete destruction. The study aim was to evaluate immunological factors and their potential role in biological heart valve destruction. METHODS: Allogeneic (n = 10) and xenogeneic (n = 3) aortic valve prostheses, as well as aortic valves retrieved from transplanted human hearts which had to be replaced due to chronic graft rejection (n = 4), were analyzed. Aortic valves from human donor hearts (n = 4) served as controls. Evaluated adhesion molecule expression included: selectin family ELAM-1, CD62; integrin family VLA-1, -2, -3, -4, -5 and -6; immuoglobulin supergene family PECAM-1, ICAM-1 and -2, and class I heavy chain proteins; complementary adhesion molecules CD34, CD44 and von Willebrand factor. RESULTS: ELAM-1, ICAM-1 and -2, CD34, CD44 and class I heavy chain proteins, which play significant roles during inflammatory processes, showed stronger expression patterns in allogeneic and xenogeneic aortic heart valve prostheses compared to native or chronically rejected valves. Furthermore, allogeneic and xenogeneic valves showed a strong thrombogenicity which stained positive for von Willebrand factor outside endothelial cells on these valves. Integrin molecules as well as CD62 showed only mild differences. CONCLUSION: Immunological reactions play a pivotal role in the degeneration of biological heart valve prostheses. As immunosuppressive therapy after heart valve replacement is not a viable option, novel approaches in 'tissue engineering' may help to avoid tissue degeneration while preserving the advantage of biological tissue origin.

Adult↗

PubMed2002

Inhibition of aortic allograft vasculopathy by local delivery of platelet-derived growth factor receptor tyrosine-kinase blocker AG-1295.

BACKGROUND: Signal transduction through the platelet-derived growth factor (PDGF)/PDGF-receptor (PDGFR) system has been linked to vascular smooth muscle cell migration and proliferation leading to allograft vasculopathy. This study describes the effect of the tyrphostin AG-1295, a specific PDGFR tyrosine-kinase inhibitor, on neointimal formation in this disease. METHODS AND RESULTS: Rat aortic allografts transplanted from dark agouti (RT1 ) donors to Wistar-Furth (RT1 ) recipients were assessed in a new treatment model for local drug delivery from polymeric carrier matrices precoated with AG-1295. Matrices were wrapped around the graft immediately after transplantation. The recipients received no background immunosuppression. At day 80 posttransplantation, intimal thickness in AG-1295-treated grafts was reduced when compared to controls (11.8+/-9.1% intimal thickness vs. 23.7+/-6.4% intimal thickness; P=0.042). This finding corresponded to inhibition of intimal PDGFR-beta expression in AG-1295-treated grafts at day 20 posttransplantation (P =0.029 vs. allogeneic controls). CONCLUSIONS: The tyrphostin AG-1295 reduces neointimal formation in aortic allograft vasculopathy by inhibition of PDGFR-beta-triggered tyrosine phosphorylation. Local drug release of specific tyrosine-kinase inhibitors from perivascularly co-implanted polymeric carrier matrices is effective in the prophylaxis of allograft vasculopathy under selected experimental conditions.

Animals↗

PubMed2002

Construction of autologous human heart valves based on an acellular allograft matrix.

OBJECTIVE: Tissue engineered heart valves based on polymeric or xenogeneic matrices have several disadvantages, such as instability of biodegradable polymeric scaffolds, unknown transfer of animal related infectious diseases, and xenogeneic rejection patterns. To overcome these limitations we developed tissue engineered heart valves based on human matrices reseeded with autologous cells. METHODS AND RESULTS: Aortic (n=5) and pulmonary (n=6) human allografts were harvested from cadavers (6.2+/-3.1 hours after death) under sterile conditions. Homografts stored in Earle's Medium 199 enriched with 100 IU/mL Penicillin-Streptomycin for 2 to 28 days (mean 7.3+/-10.2 days) showed partially preserved cellular viability (MTT assay) and morphological integrity of the extracellular matrix (H-E staining). For decellularization, valves were treated with Trypsin/EDTA resulting in cell-free scaffolds (DNA-assay) with preserved extracellular matrix (confocal microscopy). Primary human venous endothelial cells (HEC) were cultivated and labeled with carboxy-fluorescein diacetate-succinimidyl ester in vitro. After recellularization under fluid conditions, EC were detected on the luminal surfaces of the matrix. They appeared as a monolayer of positively labeled cells for PECAM-1, VE-cadherin and Flk-1. Reseeded EC on the acellular allograft scaffold exhibited high metabolic activity (MTT assay). CONCLUSIONS: Earle's Medium 199 enriched with low concentration of antibiotics represents an excellent medium for long time preservation of extracellular matrix. After complete acellularization with Trypsin/EDTA, recellularization under shear stress conditions of the allogeneic scaffold results in the formation of a viable confluent HEC monolayer. These results represent a promising step toward the construction of autologous heart valves based on acellular human allograft matrix.

Aortic Valve↗

PubMed2002

High failure rate after valve-sparing aortic root replacement using the "remodeling technique" in acute type A aortic dissection.

BACKGROUND: Valve-sparing surgery including the replacement of the sinus of valsalvae were initially meant to be promising approaches in the treatment of acute type A aortic dissection. However, the long-term outcome after valve-sparing aortic root replacement in acute type A dissection is currently the subject of intense debate, and the evidence reported in the literature is sparse. Here we report on our experience on valve sparing aortic root replacement inpatients with acute type A dissection. METHODS: From August 1995 to November 2000, 30 patients with acute type A dissection received valve-sparing aortic root replacement. Two different techniques were performed: the "remodeling" technique, first described by Yacoub in 1983 (8 patients) and the "reimplantation" technique, initially described by David and Feindel, in 1992 (22 patients). Endpoints of the study were early and late mortality, as well as aortic valve-related complications and reoperations. RESULTS: The mean follow-up time was 22.6+/-15.4 months. The overall 30 day mortality was 17% (5/29) and the late mortality 4% (1/24). During the observation period, 4 patients had to be reoperated (n=3) for acute aortic valve regurgitation after aortic root remodeling and for acute aortic valve endocarditis (n=1) after aortic root reimplantation. In the 3 patients with acute aortic valve regurgitation, symptoms occurred 44, 24, and 17 months after the initial operation in these patients. Intraoperatively prolapsing aortic leaflets because of commissural detachment was found in all 3 cases. In all other patients the latest echocardiographic follow-up examination revealed freedom from aortic regurgitation higher than grade 1. CONCLUSIONS: The high failure rate of aortic root remodeling inpatients with acute type A aortic dissection is discouraging. Whether this technique should be applied in acute type A aortic dissection is questionable. In contrast, aortic root reimplantation lead to favorable midterm outcome. Thus, we recommend consideration of this technique for surgical treatment of patients with acute type A aortic dissection.

Acute Disease↗

PubMed2002

Absence of PERV specific humoral immune response in baboons after transplantation of porcine cells or organs.

Xenotransplantation of pig organs seems a promising way of overcoming the prevailing limitation on allotransplantation due to donor numbers. However, as porcine endogenous retroviruses (PERVs) can infect human cells in vitro, there is substantial concern regarding the risk of a PERV infection in xenogeneic transplant recipients. Cultured porcine endothelial cells, stimulated peripheral blood mononuclear cells, and pancreatic islet cells can release PERV infectious for human cells in vitro, but it is currently unknown whether PERV is released in vivo, whether these viral particles can infect the transplant recipient, and whether they are pathogenic. In a retrospective study 15 immunosuppressed baboons were tested for a specific immune response against PERV after transplantation of porcine endothelial cells, mononuclear blood cells, and lungs. Anti-PERV antibody expression was analyzed with peptide-based, enzyme-linked immunosorbent assays and highly sensitive Western Blot assays. This xenotransplantation study using nonhuman primates found no evidence of PERV specific humoral immune response. Our data suggest that no productive PERV infection and no continuous PERV release takes place in the nonhuman primates analyzed in this study.

Animals↗

PubMed2002

[Current status of lung transplantation: patients, indications, techniques and outcome].

BACKGROUND: Lung transplantation has evolved to a standard treatment modality for patients suffering from end-stage lung diseases. INDICATIONS: Accepted indications for lung transplantation include chronic obstructive pulmonary disease of the lung (COPD) and other causes of emphysema (i.e., alpha-1-antitrypsin deficiency), parenchymal diseases (i.e., idiopathic pulmonary fibrosis), genetic disorders such as cystic fibrosis, vascular diseases (i.e., primary pulmonary hypertension), chronic infectious diseases (i.e., bronchiectasis), as well as rare indications such as lymphangioleiomyomatosis or sarcoidosis. TREATMENT AND OUTCOME: This article reviews the current strategies in the treatment of lung transplant recipients, surgical techniques, limitations of and outcome after lung transplantation.

Adolescent↗

PubMed2002

Predictors of aneurysmal formation after surgical correction of aortic coarctation.

OBJECTIVES: We sought to identify the predictors of aneurysmal formation after surgical correction of aortic coarctation. BACKGROUND: In 9% of patients, aneurysms develop late after corrective surgery of coarctation of the aorta, with a 36% mortality rate if left untreated. However, the predictors of postsurgical aneurysmal formation are unknown. METHODS: Of 25 aortic aneurysms requiring corrective surgery 152 +/- 78 months after the initial coarctation repair, 8 were located in the ascending aorta (type A) and 17 at the site of previous repair (local type). Seventy-four patients without progression of the aortic diameter within 189 +/- 71 months after coarctation repair were used for categorical data analysis in an attempt to identify the predictors of postsurgical aneurysmal formation. RESULTS: Advanced age at coarctation repair (p = 0.004) and patch graft technique (p < 0.0005) independently predicted local aneurysmal formation. Type A aneurysm was univariately associated with the presence of a bicuspid aortic valve (p = 0.02), advanced age at coarctation repair (p = 0.044) and a high preoperative peak systolic pressure gradient of 74 +/- 21 mm Hg (p = 0.041). Conversely, multivariate analysis confirmed only the presence of a bicuspid aortic valve (p = 0.015) as an independent predictor of type A aneurysm. Receiver operating characteristic curve analysis revealed that 72% of patients with a postsurgical aneurysm had an operation at age 13.5 years or more, whereas 69% with no postsurgical aneurysm had an operation at a younger age. CONCLUSIONS: Use of the patch graft technique and late correction of coarctation can predict aneurysmal formation at the site of coarctation repair, although patients with a bicuspid aortic valve may be at risk for an aneurysm developing in the ascending aorta, particularly after late repair of aortic coarctation with high preoperative pressure gradients.

Adolescent↗

PubMed2002

Mutation screening of the fibrillin-1 (FBN1) gene in 76 unrelated patients with Marfan syndrome or Marfanoid features leads to the identification of 11 novel and three previously reported mutations.

Mutations in the gene encoding fibrillin-1 (FBN1) cause Marfan syndrome (MFS) and other related connective tissue disorders. In this study we performed SSCP to analyze all 65 exons of the FBN1 gene in 76 patients presenting with classical MFS or related phenotypes. We report 7 missense mutations, 3 splice site alterations, one indel mutation, one nonsense mutation and two mutations causing frameshifts: a 16bp deletion and a single nucleotide insertion. 5 of the missense mutations (Y1101C, C1806Y, T1908I, G1919D, C2251R) occur in calcium-binding Epidermal Growth Factor-like (EGFcb) domains of exons 26, 43, 46 and 55, respectively. One missense mutation (V449I) substitutes a valine residue in the non-calcium-binding epidermal growth factor like domain (EGFncb) of exon 11. One missense mutation (G880S) affects the "hybrid" motif in exon 21 by replacing glycine to serine. The 3 splice site mutations detected are: IVS1-1G>A in intron 1, IVS38-1G>A in intron 38 and IVS46+5G>A in intron 46. C628delinsK was identified in exon 15 leading to the substitution of a conserved cysteine residue. Furthermore two frameshift mutations were found in exon 15 (1904-1919del ) and exon 63 (8025insC) leading to premature termination codons (PTCs) in exon 17 and 64 respectively. Finally we identified a nonsense mutation (R429X) located in the proline rich domain in exon 10 of the FBN1 gene. Y1101C, IVS46+5G>A and R429X have been reported before.

Adolescent↗

PubMed2002

[Recent developments in surgery of the thoracic aorta].

Aortic surgery is under continuous development. This applies to the aortic root where more and more reconstructive efforts are being made but also to intraoperative means of organ protection. Likewise, the endoluminar stent graft approach to downstream pathologies of the aorta has broadened the classical treatment option "replacement" by "exclusion". Some of these evolving changes in operative strategies and indications are discussed on the basis of a single-center experience.

Aortic Dissection↗

PubMed2002

[Surgery in advanced heart failure].

BACKGROUND: ACE inhibitors and beta blockers have reduced morbidity and mortality from chronic heart failure significantly during the last years. Apart from medical therapy several surgical strategies for the treatment of heart failure are available. PREREQUISITES OF SURGICAL TREATMENT: Surgical treatment should be directed towards the underlying etiology and mechanisms. To decide for a special surgical therapy indications and contraindications must be considered. SURGICAL PROCEDURES: The surgical therapy of heart failure can be performed with or without replacement of the heart. Especially concerning the organ-conserving techniques there has been significant progress during the last years: left ventricular aneurysmectomy, mitral valve surgery as well as high-risk coronary artery bypass surgery and electrostimulating procedures. Concerning heart replacement therapy, cardiac transplantation with a 10-year survival of 50% still remains superior to all available mechanical devices at the moment.

Cardiomyoplasty↗

PubMed2002

[Is chronic graft rejection the reason for degenerative changes in allogeneic and xenogeneic heart valve prostheses: immunohistochemical evaluation of inflammatory factors].

OBJECTIVES: After a period of 5 to 10 years, biological heart valve prostheses undergo degenerative processes, which finally lead to dysfunction and complete destruction. Although many efforts have been made to identify underlying mechanisms, many questions remain unanswered. Here we evaluate immunological factors and their potential role in biological heart valve destruction. PATIENTS AND METHODS: Allogeneic (n=10) and xenogeneic (n=3) aortic valvular prostheses, as well as aortic valves retrieved from transplanted human hearts, which had to be replaced because of chronic graft rejection (n=4) were analyzed. Aortic valves from human donor hearts (native) (n=4), which were considered not transplantable served as controls. Endothelial expression patterns of the following adhesion molecules were analyzed by immunohistochemistry: selectin family: ELAM-1, CD62, integrin family: VLA-1, -2, -3, -4, -5, and -6, immunoglobulin supergene family: PECAM-1, ICAM-1, and -2, and class I heavy chain proteins, complementary adhesion molecules: CD34, CD44 and the von Willebrand factor. RESULTS: ELAM-1, ICAM-1 and -2, CD34, CD44 and class I heavy chain proteins, all molecules which play significant roles during inflammatory processes, showed stronger expression patterns in allogeneic and xenogeneic aortic heart valve prostheses compared to native or chronically rejected valves. Furthermore, the von Willebrand factor stained positive only on allogeneic and xenogeneic valves. Only mild differences were observed regarding the expression of integrin molecules and CD62. CONCLUSIONS: Immunological reactions play a major role in the degeneration of biological heart valve prostheses. This is underlined by observations made on aortic valves from chronically rejected cardiac grafts, which did not show any degenerative alterations. Thus, since immunosuppressive therapy after heart valve replacement is no reasonable alternative, novel and future approaches in "tissue engineering" will hopefully help avoid tissue degeneration, while preserving the advantage of biological tissue origin.

Animals↗

PubMed2002

Aortic valve reimplantation in ascending aortic aneurysm: risk factors for early valve failure.

BACKGROUND: Aortic root reconstruction by reimplantation of the native valve represents a new therapeutic option for ascending aortic aneurysms. Information about long-term follow-up is limited, and possible predictors for failure of reconstruction have not been evaluated so far. METHODS: After aortic valve reimplantation 101 patients were followed in a prospective observational study. From this cohort the first 75 consecutive patients with a complete 1-year follow-up were chosen for further analysis. Clinical and echocardiographic data were obtained preoperatively, intraoperatively, and early postoperatively, as well as after 1 year of follow-up. RESULTS: No mortality was observed within the first 30 days. There were 52 male patients, mean age was 49.1+/-20.6 years, observation period was 35.6+/-20.6 months, and Marfan's syndrome was present in 22 patients. Although in 67 patients a stable valve function could be demonstrated, 5 patients presented with mild aortic insufficiency or had to be operated on again for secondary valve failure (n = 3). Analyzing possible demographic, disease-related, and procedure-related risk factors in a multivariable approach, only level of coaptation within the graft (as assessed by echocardiography) could be identified as being related to the subsequent development of aortic insufficiency. Coaptation level within the tube graft (type A) resulted in a mean aortic regurgitation grade of 0.3+/-0.5 as compared with a mean grade of 2.5+/-0.6 for a coaptation type C (below the prosthesis; p < 0.001). CONCLUSIONS: Aortic valve reimplantation is a promising alternative to alloprosthetic composite replacement. A level of coaptation within the tube graft is essential to achieve valve competence.

Adolescent↗

PubMed2002

Heart transplantation: echocardiographic assessment of morphology and function after more than 10 years of follow-up.

BACKGROUND: Over recent years, heart transplantation (HTX) developed into a successful option for long-term treatment of end-stage heart failure. Ten-year survival ranges between 40% and 50%. Little is known, however, about function and morphology of transplanted hearts during follow-up of more than 10 years. METHODS: In a consecutive cohort of 65 patients (55 male, 54.6 +/- 12.1 years at the time of transplantation), graft function was assessed by color Doppler echocardiography 12.5 +/- 1.4 years after heart transplantation (10 to 15 years). RESULTS: Left atrial and ventricular dimensions were found in a normal range (LA 37.7 +/- 8.9 mm, LV enddiastolic 45.6 +/- 6.4 mm, 30 to 71 mm). Ejection fraction (EF) of 71 +/- 11.7% and a fractional shortening of 35.3 +/- 10.3% presented with normal values. Left ventricular mass (male 263.8 +/- 111.4 g, female 373.0 +/- 181.1 g) was slightly increased resulting in mild hypertrophy in women. Focused on right ventricular morphology, enlargement of both the right atrium and the right ventricle (RA 40.7 +/- 11.8 mm, RV 37.4 +/- 8.3 mm) was observed in the majority of the patients. Tricuspid valve insufficiency (> grade II) was present in 46 of 65 patients; 5 patients had previously undergone tricuspid valve replacement. Atrial filling waves were detectable in only 47 of 65 patients, thus, 28% of patients showed signs of LA-dysfunction. CONCLUSIONS: More than 10 years post-HTX, cardiac grafts were characterized by normal left ventricular dimensions and ejection fraction. LA-dysfunction and RV-enlargement associated with tricuspid insufficiency were frequent findings, however, not associated with clinical signs of congestive heart failure in the majority of patients.

Adult↗

PubMed2002

Results of valve-sparing aortic root reconstruction in 158 consecutive patients.

BACKGROUND: This study assesses the durability and clinical outcome of valve-sparing aortic root reconstruction using the reimplantation technique in a single center cohort. METHODS: From July 1993 to July 2001, 158 patients underwent replacement of the ascending aorta with native valve reimplantation. Mean age of patients was 52 +/- 17 years (9 to 84 years), 103 were men (65%). Thirty-four patients (22%) suffered from Marfan's syndrome. Aortic dissection Stanford type A was present in 29 patients (19%) (22 acute, 7 chronic), and concomitant partial or total arch replacement was necessary in 57 patients (36%). One or more additional procedures were performed in 28 patients (18%). Mean follow-up was 36 +/- 25 months (0.4 to 96 months). RESULTS: Thirty-day mortality was 3.8% (6 patients), but only 2.2% in elective patients. Mean bypass time was 169 +/- 50 minutes (99 to 440 minutes), aortic cross-clamp time was 129 +/- 31 minutes (79 to 205 minutes). In patients undergoing arch replacement, circulatory arrest was 26 +/- 18 minutes (7 to 99 minutes). During follow-up, there were 5 (3.3%) cardiac-related late deaths. Grade of aortic insufficiency (AI) decreased from 2.3 +/- 1.1 (0 to 4) preoperatively to 0.23 +/- 0.44 (0 to 2) postoperatively (p < 0.0001). Six patients required aortic valve replacement, 4 of those due to progressive AI. Average grade of AI increased significantly to 0.42 +/- 0.61 (0 to 3) at latest evaluation (p = 0.002). Two patients experienced a transient ischemic attack within the first postoperative week. No further thromboembolic complications were noticed. All patients presented with a favorable exercise tolerance. CONCLUSIONS: The aortic valve reimplantation technique achieves excellent clinical outcome with few complications even in complex pathologies. Lack of anticoagulation and favorable durability encourage wider and earlier use of this technique.

Adolescent↗

PubMed2002

Valve-sparing aortic root reconstruction in patients with significant aortic insufficiency.

BACKGROUND: To assess the feasibility and outcome of the valve-sparing aortic root reimplantation technique in patients with severe preoperative aortic insufficiency (AI). METHODS: Within 8 years we have operated on 158 patients with aneurysms of the ascending aorta using the reimplantation technique. We identified 83 patients with AI grade 3 or 4 (mean 3.1 +/- 0.4) preoperatively (study group). This cohort was compared with 71 patients with AI grade 2 or less (mean 1.3 +/- 0.9; control group) with regard to mortality, operative variables, complications, need for reoperation, postoperative AI, and clinical presentation during follow-up. RESULTS: Patient demographics were comparable in both groups. However, Marfan's syndrome (32% versus 13%, p = 0.006) and acute type A aortic dissection (20% versus 8.4%, p = 0.059) were more frequent in the control group. In addition, bypass (177 +/- 60 minutes versus 160 +/- 36 minutes, p = 0.022) and cross clamp times (133 +/- 34 minutes versus 124 +/- 27 minutes, p = 0.049) were significantly longer in controls. Mortality was low in the study group and comparable with controls (30-day, 3.6% versus 4.2%; during follow-up, 3.8% versus 5.9%; p = not significant [NS]). Reoperation rate was almost identical in both groups (3.8% versus 4.4%, p = NS). Mean grade of AI was significantly higher in the study group early postoperatively (0.31 +/- 0.46 versus 0.18 +/- 0.42, p = 0.049) but comparable at the last visit (0.43 +/- 0.58 versus 0.42 +/- 0.62, p = NS). During follow-up neither thromboembolic complications nor bleeding events were noted in either group. Clinical performance at the last visit revealed no significant difference between the groups. CONCLUSIONS: Preoperative severe aortic insufficiency does not impair the excellent outcome seen after a mean of 3 years of follow-up in patients undergoing the reimplantation technique for valve-sparing aortic root reconstruction.

Adolescent↗

PubMed2002

The impact of spinal angiography on the neurological outcome after surgery on the descending thoracic and thoracoabdominal aorta.

BACKGROUND: Neurologic complications remain one of the major concerns in surgery on the descending thoracic and thoracoabdominal aorta. The impact of preoperative spinal angiography on postoperative neurologic outcome was assessed. METHODS: Between September 1993 and December 1999, 109 patients (mean age, 58.2 years; range, 24 to 77) underwent preoperative spinal angiography: 50 (45.9%) for aneurysm and 59 (54.1%) for chronic dissection. Sixty-one patients (56.0%) underwent replacement of the descending thoracic aorta whereas the thoracoabdominal aorta was replaced in 48 (44.0%) patients. All intercostal or lumbar arteries that had previously been visualized as the origin of the great radicular artery (GRA) were preserved. RESULTS: The origin of the GRA was located by spinal angiography in 65 of the 109 patients (59.6%). It was found between level T-5 and L-3 and on the left side in 75.4% (49 of 65) patients. In patients with aneurysms, it was identified less frequently (48%) compared with patients with chronic dissection (69.5%, p = 0.02). The overall operative mortality rate was 5.5% (6 of 109 patients). There were 7 patients (6.4%) with postoperative paraplegia. In 3 of them the origin of the GRA had been reimplanted. CONCLUSIONS: Even in patients with an identified and subsequently reimplanted GRA, postoperative paraplegia could not always be prevented. Spinal angiography has no impact on the neurologic outcome of thoracic and thoracoabdominal aortic replacement.

Adult↗

PubMed2002

Intraoperative acute type A dissection caused by an intra-aortic filter (EMBOL-X) in a patient undergoing mitral valve re-replacement for acute endocarditis.

We report on the case of a 60-year-old male patient who underwent mitral valve re-replacement for acute mechanical valve endocarditis. When an intra-aortic filter (EMBOL-X Inc, Mountain View, CA) was inserted through the arterial cannula in order to prevent embolization from a floating thrombus attached to the mitral valve prosthesis, our patient developed acute type A aortic dissection. This, to our knowledge, is the first report on this kind of complication using intra-aortic filter systems. Here we discuss a potential mechanism that might have led to the event of acute type A dissection in our case. Furthermore we point out strategies that might help to prevent this life-threatening complication in the future.

Aortic Dissection↗

PubMed2002

Clinical relevance of intracranial high intensity transient signals in patients following prosthetic aortic valve replacement.

OBJECTIVES: There has been frequent report on transcranially detected microembolic signals (HITS) following cardiac surgery using extracorporeal bypass support. The clinical relevance of HITS, however, has yet to be clarified. The incidence of thromboembolic events is increased following mechanical heart valve replacement. The purpose of this study was to quantify postoperative HITS after implantation of two types of prosthetic aortic valves and to compare both types of mechanical valves with respect to the generation of HITS. In addition, HITS rates were correlated with clinical, echocardiographical and laboratory findings. METHODS: Forty-two patients following implantation of either a Sorin Biomedica heart valve (n=22, group A) or a Tekna Duromedics mechanical valve (n=20, group B) were examined. A group of ten healthy volunteers served as control. Clinical, echocardiographic, carotid artery duplex and laboratory examinations were performed in all patients. A 60 min bilateral transcranial doppler monitoring of the medial cerebral artery (MCA) was also carried out in order to evaluate cerebral blood flow. RESULTS: In group A 14 of 22 patients were positive for HITS (53%), with an average of 16.4+/-19 HITS/pt.h. In group B 15 of 20 patients were HITS positive (75%) with an average amount of 14.4+/-24 HITS/pt.h. The incidence of HITS was not significantly different between the two groups. No correlation was seen between the HITS-rate/h and neurological findings, duplex sonographic results, mechanical valve size and anticoagulation regimen (P>0.05). However, a negative correlation was observed between patient age and HITS-rate (P=0.02) as well as between the NYHA degree and HITS-rate (P=0.018). The HITS-rate also correlated with postoperative time (P=0.042). No HITS were detected in the control group. CONCLUSIONS: HITS do not correlate with the individual clinical status and, thus, cannot predict the occurrence of neurological deficits in patients following mechanical aortic valve implantation.

Aged↗