PubMed Health⌕ Search

Biomedical subjects

M Havel

Publications and source records attributed to M Havel.

At least 19 recordsLinked to original sources
PubMed1995

Transoesophageal echocardiographic follow-up of patients with surgically treated aortic aneurysms.

In the present study, biplane transoesophageal echocardiography (TEE) was scheduled as part of an aneurysm surveillance programme during routine ambulatory follow-up of 37 patients following aortic aneurysm surgery. Time from surgery ranged from 3-72 months. Twenty-two patients had had aortic dissection and 15 non-dissecting aneurysms. Nineteen patients received an interposition graft of the ascending aorta, 12 valved conduit and six an interposition graft of the descending thoracic aorta. TEE showed enlargement of the sinus of Valsalva > 45 mm in seven patients. Dilatation > 45 mm of one or more aortic segments was found in four patients. An intimal flap was present in all patients, with primary aortic dissection if the initial dissection extended beyond the replaced segment. This was the case in 17 of 22 patients with aortic dissection. One to four intimal tears were identified in 15 of these patients. In all patients with intimal tears, flow was detected by colour flow Doppler in the false lumen. Thrombus formation was nil or minimal in the false lumen in 12 patients. TEE significantly influenced further management in 14 of 37 patients (38%). More frequent follow-up was scheduled in eight patients. Aortic surgery was performed electively for the second or third time in six patients based on TEE findings. We conclude that after surgical repair of aortic aneurysm, the incidence of pathological findings by TEE is high. These may have significant influence on further patient management and emphasize the need for careful follow-up.

Adult↗
PubMed1995

Surgical treatment of type A aortic dissections. Results with profound hypothermia and circulatory arrest.

Type A aortic dissection still presents an emergency situation in cardiac surgery that is associated with high morbidity and mortality rates. There has been a significant improvement in the surgical outcome since the introduction of deep hypothermia and circulatory arrest. In this study, we discuss our results after operative repair of ascending aortic dissections, using deep hypothermia and circulatory arrest. This study presents the results of 67 patients (43 men, 24 women) from 18 through 81 years of age (mean, 54 years) who underwent surgery for type A dissecting aneurysm over a period of 4 years. Type A dissection (52 acute and 15 chronic cases) was due to Marfan syndrome in 12 patients, to atherosclerotic disease of the aorta in 27 patients, and to traumatic injury in 1 patient. Hypertension as the only pathologic finding was observed in 27 patients. Deep hypothermia (confirmed by isoelectric electroencephalogram) and circulatory arrest were induced in all patients. Two patients died intraoperatively due to massive bleeding (intraoperative mortality, 3%). The 30-day mortality rate was 30% (n = 20). Causes of perioperative deaths in order of frequency were multi-organ failure (n = 11), myocardial infarction (n = 2), postoperative bleeding (n = 2), cerebrovascular insult (n = 2), and sepsis (n = 1). The mean intensive care unit stay of the surviving 47 patients (72%) was 8 days, followed by a mean of 21 additional days in the hospital. Our experience with profound hypothermia and circulatory arrest, used in combination with coated grafts, supports our conviction that this is the method of choice for the treatment of type A dissecting aneurysm.

Adolescent↗
PubMed1995

[Surgery of thoracic and thoraco-abdominal aneurysms using deep hypothermia and cardiovascular arrest with continuous administration of blood cardioplegia].

Between January 1991 and February 1993, 14 patients (3 female, 11 male) aged between 21 and 79 years (mean 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, in 3 patients coronary artery by pass grafting was performed before. All patients were operated using cardiopulmonary bypass with continuous blood cardioplegia, hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, 0-EEG) and posterolateral exposure. All patent lower intercostal and lumbar arteries (Th3-L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0, after replacement of the thoracoabdominal aorta 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurologic deficit, renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic and 18 days for patients after replacement of the thoracoabdominal aorta. Our results indicate the method of elective hypothermia and circulatory arrest effective in spinal cord protection. The increase in the tolerable duration of spinal cord ischemia supports the reimplantation of all intercostal and lumbar vessels.

Adult↗
PubMed1995

Aortic valve resuspension in ascending aortic aneurysm repair with aortic insufficiency.

BACKGROUND: The known complications of prosthetic valve replacement in patients with an ascending aortic aneurysm and secondary aortic regurgitation who frequently have a morphologically normal aortic valve have prompted interest in valve-sparing aneurysm repair procedures. The aim of this study was to define the echocardiographic criteria for identifying suitable candidates for ascending aortic aneurysm repair that spares the aortic valve. We also examined the perioperative and intermediate-term results of this innovative procedure. METHODS: Fifteen patients underwent ascending aortic replacement with resuspension of the native valve within a vascular prosthesis and reimplantation of the coronary ostia. Echocardiography was performed preoperatively and intraoperatively, before discharge, and during follow-up. Thirteen patients had nondissecting aneurysms, and 2 patients had a Standford type A aortic dissection. The mean age of the patients was 48 +/- 18 years. Only patients with morphologically normal aortic leaflets and leaflets of similar size were selected. RESULTS: There was one death perioperatively, and this was due to sepsis. The procedure failed in 1 patient, and a valved conduit was implanted during the same operation. In the 13 others the aortic annulus diameter was significantly reduced from 27.1 +/- 2.2 mm preoperatively to 22.2 +/- 1.9 mm postoperatively (p < 0.05). The severity of aortic insufficiency decreased from 2.9 +/- 0.7 to 0.6 +/- 0.4 (p < 0.05). The peak aortic gradient increased from 11.5 +/- 6.5 to 20.3 +/- 16 mm Hg. A slight increase in the aortic annulus diameter to 24.3 +/- 1.0 mm and normalization of the peak aortic gradient to 9.8 +/- 7.8 mm Hg were noted at follow-up. There was no significant increase in aortic insufficiency. CONCLUSIONS: In selected patients undergoing ascending aortic aneurysm repair who have normal aortic leaflets but secondary aortic regurgitation, the native valve can be spared through this novel operation. The aortic annulus size is reduced significantly, thereby effectively eliminating hemodynamically significant aortic regurgitation. The intermediate-term results are promising, but the long-term durability of this type of repair needs to be determined.

Adult↗
PubMed1995

[Results of valve-sparing correction of aortic valve insufficiency].

The risk of valve-related complications and the necessity of anticoagulation in patients with prosthetic valves, has led to new operative techniques in the correction of severe aortic insufficiency. In the last 2 years, 35 patients (mean age 41.3 years, range 10-80 years) with aortic insufficiency underwent reconstructive valves surgery. Eighteen patients had a commissuroplasty with or without triangular resection. In 5 patients with perforation, the valves could be reconstructed with a pericardial patch. In 12 patients with insufficiency due to aortic aneurysm, the valves were resuspended within the aortic prosthesis. In 2 patients the aortic valves were replaced intraoperatively because of unsatisfactory results. The perioperative mortality was 5.7%. The echocardiographic degree of aortic insufficiency decreased from 3.3 +/- 0.5 preoperatively to 0.45 +/- 0.53 postoperatively. Two patients were reoperated within the first week. Five of 23 patients at 1-year follow-up have mild to moderate aortic insufficiency. Mean ventricular dimensions and function at discharge and after 1-year follow-up are normal. With the new operative techniques described recently, valve-sparing corrections of aortic insufficiency are possible in an increasing number of patients, and autologous valve tissue can be saved. With more refinement of surgical technique, early postoperative results will further improve.

Adolescent↗
PubMed1994

Sinus of Valsalva aneurysm: a late complication after repair of ascending aortic dissection.

Surgical advances and the introduction of new more rapid and accurate diagnostic techniques have led to significant improvement in the survival of patients with aortic aneurysms. However, considerable long-term morbidity and mortality remains a concern. In the present study we report on the occurrence of sinus of Valsalva (SV) aneurysm after repair of the ascending aorta for aortic dissection as a significant long-term complication. Since transesophageal echocardiography (TEE) became available it has been used for the follow-up of 33 hospital survivors after ascending aortic replacement for a mean of 27 +/- 20 months. Those patients who received a valved conduit were excluded from this analysis. The aortic valve was conserved in 22 patients: 17 had a dissecting aneurysm involving the ascending aorta and 4 patients non-dissecting aneurysms. A sinus of Valsalva diameter > 45 mm was considered an aneurysm and was found in a total of 7 patients (33%), 5 being patients with aortic dissection. The overall reoperation rate on account of SV aneurysms was 24%. We conclude that SV aneurysm is a significant long-term complication of patients after repair of the ascending aorta. In the light of these results we have changed our operative policy of repair to include resorcin glue as a reinforcing agent or to perform more extensive repair.

Aortic Dissection↗
PubMed1994

Elective surgery for blunt cardiac trauma.

The cases of eight patients who underwent elective surgery for blunt cardiac trauma are presented. All but one experienced multiple trauma and the median Injury Severity Score was 26 (range, 18-59). A posttraumatic cardiac defect was diagnosed from 1 day up to 6.5 years (median, 3 weeks) after the accident. These included mitral regurgitation (n = 4), ventricular septal defect (n = 2), atrial septal defect with mitral regurgitation (n = 1), and ventricular aneurysm (n = 1). Elective cardiac surgery was performed from 4 weeks up to 12 years after the traumatic event (median, 18.5 months). A history of blunt chest trauma requires careful clinical follow-up supported by echocardiography in asymptomatic patients. Surgical therapy is performed according to standard techniques and the results are comparable with those of non-trauma surgery.

Adolescent↗
PubMed1994

Thoracoabdominal aneurysm repair: spinal cord protection using profound hypothermia and circulatory arrest.

Between January 1991 and February 1993, 14 patients (11 male, 3 female) between 21 and 79 years of age (median 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, and in three patients coronary artery bypass grafting had previously been performed. All patients were operated on a via a posterolateral thoracotomy using cardiopulmonary bypass with continuous blood cardioplegia and hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, flat-EEG). All patent lower intercostal and lumbar arteries (T3 to L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0%; after replacement of the thoracoabdominal aorta, mortality was 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurological deficit or renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic aorta and 18 days for patients after replacement of the thoracoabdominal aorta. Our results suggest that use of elective hypothermia and circulatory arrest for spinal cord protection is highly effective. We, therefore, recommend this method for complex reconstructions of the thoracoabdominal aorta.

Adult↗
PubMed1994

Aprotinin does not decrease early graft patency after coronary artery bypass grafting despite reducing postoperative bleeding and use of donated blood.

Forty-five male patients with planned coronary artery bypass operation were randomized in a double blind fashion to receive either 6 million kallikrein inactivator units of aprotinin (high-dose group), 2 million kallikrein inactivator units of aprotinin (low-dose group), or placebo (control group). Postoperative bleeding was significantly decreased in both aprotinin groups in comparison to that in the control group (590 ml [290 to 1800 ml] high-dose group and 650 ml [280 to 1900 ml] low-dose group versus 920 ml (350 to 2700 ml) control group, p < 0.001). There was no difference between the two aprotinin groups. The need for postoperative blood transfusion was significantly lower in the aprotinin groups (1.46 [0 to 4] blood units high-dose group and 1.65 [0 to 5] blood units low-dose group versus 2.43 [0 to 7] blood units control group, p < 0.05). All patients underwent coronary angiography between the seventh and twelfth postoperative day. No difference was found among the three groups in patency of vein grafts-93.8% in the high-dose group, 94.5% in the low-dose groups, and 93.3% in the control group. Therefore, aprotinin significantly reduced postoperative bleeding and transfusion requirement after coronary artery bypass grafting without influencing early graft patency.

Aprotinin↗
PubMed1994

[Emergency management of ruptured/dissecting aortic aneurysm--diagnosis and therapeutic strategies].

Between December 1991 and January 1994 fifteen patients with a ruptured abdominal aortic aneurysm and seven patients with a dissecting aortic aneurysm were treated in our emergency department. Dissection/rupture of an aortic aneurysm is still a dramatic event with poor outcome, whereby survival depends largely on early diagnosis. In most cases the diagnosis can be made with reasonable assurance by history taking and physical examination. The most frequent differential diagnoses are pulmonary embolism and myocardial infarction (thoracic aneurysms) and renal or biliary colic and lumbago (abdominal aneurysms). The largest delay in commencing therapy is caused by patients' hesitation to call the Emergency Medical Service. Chest X-ray, echocardiography and abdominal sonography are of high diagnostic value, computed tomography confirms the diagnosis in most cases. Our Emergency Department provides the facilities for rapid diagnosis and interdisciplinary preoperative management of dissecting/ruptured aortic aneurysms.

Adult↗
PubMed1993

[Valve saving correction of aneurysms of the ascending aorta with aortic insufficiency or annular dilatation].

The current technique to correct aneurysms of the ascending aorta with incompetence of the aortic valve or dilatation of the aortic root is the implantation of a valved conduit. In many cases however structurally normal aortic leaflets are resected by this technique and patients are at the risk of complications due to mechanical heart valve prostheses and the necessary anticoagulation respectively. By resuspension of the aortic valve into the aortic prostheses similar to the technique used at implantation of homograft valves, competence of the valve can be restored and the dilatation of the aortic annulus can be prevented or even reduced. Our article describes the successful, valve sparing correction of an acute aortic dissection type A with dilatation of the aortic annulus in a 43 year old patient and in another patient with ascending aortic aneurysm with aortic insufficiency.

Adult↗
PubMed1993

Anomalous origin of the left coronary artery: a review of surgical management in 13 patients.

Over the last decades, surgical management of anomalous left coronary artery originating from the pulmonary artery (ALCAPA) has seen a considerable evolution. Between 1965 and 1992, 13 children with age at operation ranging between 2 months and 11 years (mean 23 months) underwent one of 5 different surgical procedures: ligation (n = 3), direct aortic reimplantation (n = 7), subclavian (n = 1) or internal mammary (n = 1) artery anastomosis, or modified aortic implantation (Vigneswaran-procedure, n = 1). There were 3 early and one late deaths resulting in an overall mortality of 30.7%. Mortality was 66.7% in the ligation group, and 20% in the revascularization group (28.6% in the subgroup with direct aortic implantation). The one late death occurred 6 months after ligation. Follow-up ranges between 3 months and 21 years, mean 7.3 years. All but one survivors are in NYHA functional class I. Following operative correction, there was clear improvement in left ventricular performance. Our data give reason to suggest ALCAPA to be more frequent than considered so far. Early surgery is recommended in all patients with ALCAPA, regardless of age or symptomatic status. Reestablishment of a two-coronary system is considered the procedure of choice. All survivors require long-term follow-up controls of early recognition of residual or progressive cardiac problems.

Austria↗
PubMed1992

Early activation of hemostasis during cardiopulmonary bypass: evidence for thrombin mediated hyperfibrinolysis.

In 14 consecutive patients undergoing cardiopulmonary bypass for coronary bypass surgery the time course of coagulation and fibrinolysis markers were measured, e. g. plasma levels of thrombin-antithrombin III (TAT) complexes, cross-linked fibrin degradation products (XIFDP) and plasmin-alpha 2-antiplasmin complexes (PAP). TAT levels exceeded the 90% baseline percentile already during CPB (after opening of aortic clamp) in 10 patients, whereas PAP and XIFDP exceeded their 90% percentile in only one patient at this time. Concerning fibrinolysis markers PAP and XIFDP the majority of patients showed elevations higher than their 90% baseline percentile only 1 h postoperation. Correlation analysis revealed significant dependencies between TAT levels during and at the end of CPB and PAP levels 1 h postoperation (R = 0.55 and R = 0.56 respectively). Furthermore, 1 h postoperation XIFDP levels were significantly correlated with both TAT and PAP. Peak XIFDP levels at the same time correlated with blood loss via thoracic drains (R = 0.56). Thus, we suggest that hyperfibrinolysis in patients undergoing CPB is at least partly due to hypercoagulation. Clinically, this may implicate that intensified anticoagulation could prevent hyperfibrinolysis and reduce postoperative blood loss.

Adult↗
PubMed1992

Transesophageal echocardiography in the emergency surgical management of patients with aortic dissection.

The diagnostic accuracy and benefit of transesophageal echocardiography were investigated in 32 patients with suspected aortic dissection. Results of transesophageal echocardiography were compared with surgical assessment. The Stanford classification was used for differentiation of dissection type. Examination time was 5 to 15 minutes. Twenty-eight patients were correctly identified to have aortic dissection; four patients had nondissecting aneurysms of the ascending aorta. Both sensitivity and specificity for detection of aortic dissection were 100%. Type of dissection was misdiagnosed in one patient. Classification of dissection type was correct in 96%. The primary entry site was correctly identified in 25 patients (89%). Aortic regurgitation was found in 57% of patients. Pericardial effusion was detected in 21%, with tamponade in one patient. Myocardial infarction was suggested by transesophageal echocardiography in 7%, and 14% had significantly reduced left ventricular function. Eight patients underwent operation based on transesophageal echocardiography alone. Intraoperative transesophageal echocardiography, performed in 20 patients, verified retrograde flow in the true lumen after femoral cannulation. Transesophageal echocardiography documented postrepair persistence of the intimal flap in aortic segments that were not operated on in all patients. Secondary tears and flow in the false lumen were detected in 35% of patients. We conclude that transesophageal echocardiography allows expedient and accurate diagnosis and classification of aortic dissection, and we recommend it as the primary bedside diagnostic modality. It can especially identify patients requiring surgical intervention without further delay caused by other diagnostic procedures.

Adult↗
PubMed1992

New aspects of the degeneration of bioprosthetic heart valves after long-term implantation.

Bioprosthetic heart valves removed 76 to 150 months after implantation were morphologically investigated to correlate structural alterations with clinical failure modes. Traditional morphologic methods of evaluating valvular heterografts, such as microradiography and electron microscopy, were complemented by undecalcified ground sections, a new technique for analyzing the distribution of mineral deposits. Apart from well-investigated mechanisms that accelerate tissue degeneration, our observations point to additional facts: (1) phagocytosis of collagen fibrils and elastic material by macrophages and foreign body giant cells in areas near tears and perforations and (2) initial calcification indicated by delicate crystals in the intercellular space arranged in close relation to the periodicity of the cross-striation pattern of collagen fibrils. The present report not only calls attention to degenerative changes that are enhanced by mechanical stress but also underlines phagocytosis as an important mechanism in the destruction of bioprosthetic heart valves.

Bioprosthesis↗
PubMed1991

The progression of mild acute cardiac rejection evaluated by risk factor analysis. The impact of maintenance steroids and serum creatinine.

The natural course of mild acute cardiac allograft rejection (MAR) under cyclosporine-based therapy is generally considered benign, and usually antirejection therapy is not instituted. The present study was undertaken to determine the frequency of and the risk factors for progression of MAR into a clinically significant (moderate or severe) rejection on subsequent endomyocardial biopsy (EMB). Among 167 cardiac recipients, transplanted from 3/1984 to 4/1990, MAR under cyclosporine-based therapy was diagnosed on 220 EMBs. Depending upon the outcome on the subsequent EMB, MAR was categorized as progressive or nonprogressive. This served as the dependent variable for a stepwise logistic regression analysis evaluating 11 covariates as potential risk factors: perioperative antibody prophylaxis (ATG vs. OKT3), maintenance therapy, underlying disease, HLA-mismatches for A- and B + DR-loci, serum creatinine (mg/dl) and cyclosporine HPLC blood level (ng/ml) at diagnosis of MAR and at subsequent biopsy, recipient age, donor age. 40 (18.2%) of 220 MARs became progressive as opposed to 37 (7.3%) of a control cohort of 507 negative EMBs (P less than 0.0001). Stepwise logistic regression yielded the type of maintenance therapy (P = 0.0019) and serum creatinine level at diagnosis of MAR (P = 0.0615) as independent predictors of progression of MAR. After adjustment for influence of maintenance therapy and serum creatinine none of the cyclosporine variables provided any additional information. MARs without maintenance steroids and low serum creatinine levels had the highest risk (37.2% observed incidence) to develop moderate or severe rejection on subsequent EMB. This analysis supports evidence that diagnosis of MAR on EMB is associated with a considerable high progression rate into clinically significant rejection when compared to negative EMBs. Progression particularly occurs in MAR under steroid-free maintenance therapy and suggests early augmentation of immunosuppression. In terms of progression of MAR serum creatinine values, obviously indicating cyclosporine nephrotoxicity, appear to reflect the extent of cyclosporine-mediated immunosuppressive activity more properly than parameters of its bioavailability by measuring cyclosporine HPLC blood levels.

Adrenal Cortex Hormones↗
PubMed1991

The monoclonal HBA-71 antibody modulates proliferation of thymocytes and Ewing's sarcoma cells by interfering with the action of insulin-like growth factor I.

The monoclonal HBA-71 antibody recognizes a Ewing's sarcoma associated antigen, which is also highly expressed on the cell surface of human cortical thymocytes and islets of Langerhans among normal tissues. The antibody was found to inhibit partially the growth of ES tumor cell lines and to trigger proliferation in thymocyte cultures. The influence of growth factors and the effect of the HBA-71 antibody was further investigated in the present study. The growth of ES tumor cells was demonstrated to be dependent on the presence of insulin-like growth factor I or insulin. The HBA-71 antibody (25 micrograms/ml) enhanced the growth stimulatory effect of IGF-I under serum-free conditions. The expression of the HBA-71 epitope is modulated positively by IGF-I and insulin and negatively by dexamethasone and human growth hormone in ES/PNET tumor cells and thymocytes. IGF-I either alone or in combination with HBA-71 stimulated the proliferation of thymocytes under serum-free conditions whereas in complete medium, IGF-I stimulated thymidine incorporation and the HBA-71 antibody either alone or in the presence of IGF-I showed inhibitory activity most likely due to down-regulation of the receptor. These data demonstrate the important role of IGF-I in the growth of ES/PNET tumor cells as well in the proliferative activity of HBA-71 positive normal thymocytes. The biological activity of IGF-I in malignant thymocytes, pancreas tumors, fetal muscle, brain, granulosa and Sertoli cells has been documented in the literature.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗