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Biomedical subjects

A Haverich

Publications and source records attributed to A Haverich.

At least 253 records · Page 14Linked to original sources
PubMed1996

Thoracoscopic creation of a pericardial window for recurrent pericardial effusion after heart transplantation.

A 56-year-old man underwent orthotopic heart transplantation (Htx) for dilative cardiomyopathy. The postoperative course was uneventful despite the appearance of pericardial effusions during the first 6 months, which required repeated drainage therapy. Six months postoperatively a pericardial window was created using a thoracoscopic approach via the right pleural cavity. The course after this intervention was uncomplicated and there was no recurrence of the pericardial effusion during 18 months of follow-up.

Endoscopy↗
PubMed1996

Myocardial protection in chronic volume-overload hypertrophy of immature rat hearts.

OBJECTIVE: The benefit of cardioplegic cardiac arrest for protection of the immature myocardium is controversial. We therefore investigated the efficacy of (1) topical hypothermia alone (2) slow cooling by coronary perfusion hypothermia and (3) cardioplegic cardiac arrest plus topical cooling for protection of isolated immature rat hearts (age: 28 days). METHODS: The isolated perfused rat heart model was used. Hearts were subjected to 8 h of global ischemia at 10 degrees C. The study was conducted after clinically relevant conditions of volume-overload myocardial hypertrophy had been established non-invasively by lifelong feeding of a diet low in iron. Parameters of left ventricular function, endothelial function, the metabolic status and myocardial injury were measured. RESULTS: Topical hypothermia provided superior protection of hypertrophied hearts with recovery of maximum developed left ventricular pressure and rate of pressure rise at 41.2% +/- 22.3% and 34.5% +/- 20.7% (mean +/- standard deviation) of preischemic values (P < 0.05 versus slow cooling and versus cardioplegia plus topical hypothermia). The same pattern of recovery was observed among control hearts. The recovery of endothelial function following protection by topical hypothermia alone measured 55% +/- 41% in hypertrophied hearts and 62% +/- 37% in control hearts, but was not recordable in all other groups. In hypertrophied hearts post-ischemic myocardial high energy content was significantly improved with topical hypothermia alone for protection when compared to the other methods. Creatine kinase leakage during reperfusion did not differ significantly among the experimental groups. CONCLUSION: Rapid cooling by topical hypothermia along provides superior protection of hypertrophied- and non-hypertrophied-immature rat hearts to additional slow pre-arrest cooling. Use of St. Thomas' Hospital cardioplegic solution No.2 (STS 2) does not improve protection, and even hinders functional recovery in hypertrophied immature hearts. Endothelial injury caused by cold asanguinous perfusates, including cardioplegia, interferes with the recovery of vascular function, which in turn, may limit mechanical function.

Age Factors↗
PubMed1996

Early postoperative flow rates after internal thoracic artery grafting for the left coronary artery system.

OBJECTIVE: The low perioperative flow rates of internal thoracic artery (ITA) conduits have been regarded as a limitation of their use in critical coronary situations with a high myocardial blood demand. To clarify whether these restrictions are justified, early postoperative flow rates were determined. METHODS: Following bilateral ITA grafting, 48 of 106 patients (April 1993-September 1994) underwent recatheterization. Subsequent to control angiography between days 8 and 12, 20 of these patients were studied by intravascular Doppler techniques applied for ITA grafts supplying the left anterior descending artery (LAD) and branches of the circumflex system (CX) (n = 20). Doppler spectral analysis allowed for determination of the average peak velocity and diastolic-systolic velocity ratio. Vascular diameters were assessed by simultaneously performed quantitative angiography and mean flow rates were calculated. All parameters were recorded at rest and following selective stimulation with nitroglycerin (0.2 mg) and papaverine (12.5 mg) to evaluate the graft flow capacity. RESULTS: Baseline values of average peak velocity at rest were 24.6 +/- 11.5 cm/s for ITA-LAD conduits and 21.9 +/- 6.8 cm/s for ITA-CX pedicles. Following dilative stimulation with papaverine, a significant increase in average peak velocities were obtained for both locations (ITA-LAD: 47.3 +/- 17.1 cm/s, ITA-CX: 42.3 +/- 11.8 cm/s). The application of nitroglycerin had a similar effect (ITA-LAD: 42.6 +/- 15.3 cm/s, ITA-CX: 40.3 +/- 10.7 cm/s). The vascular diameters of ITA conduits remained unchanged on nitroglycerin stimulation, whereas papaverine effected significant dilatation in both locations. Flow rates at rest were not significantly different (ITA-LAD: 51.0 +/- 34.2 ml/min, ITA-CX: 44.7 +/- 16.4 ml/min) and maximal flow increase was observed following papaverine stimulation of the LAD conduits (116.1 +/- 90.6 ml/min). Dilative stimulation effected an increase in diastolic-systolic velocity ratios from average values at rest in a range between 34% and 41.7% for both groups and substances. CONCLUSIONS: The basic blood flow in functioning ITA grafts appears to be similar in conduits supplying the LAD and marginal branches. Flow rates between 50 and 60 ml/min at rest should meet myocardial demands, even in the LAD position. Increased flow rates were predominantly based on higher flow velocities with an increased diastolic flow proportion. Enlargement of the graft diameter may exert additional effects, at least following papaverine stimulation at a particular concentration.

Blood Flow Velocity↗
PubMed1996

Improved endothelial cell attachment on ePTFE vascular grafts pretreated with synthetic RGD-containing peptides.

OBJECTIVES: To assess endothelial cell (EC) attachment in seeding of expanded polytetrafluoroethylene (ePTFE) vascular prostheses by application of a new technique of coupling synthetic RGD-containing peptides with the graft surface. DESIGN: Prospective, open study. SETTING: University Department of Cardiovascular Surgery and Institute of Biochemistry. MATERIALS AND METHODS: ePTFE vascular grafts (group 1) uncoated (group 2) coated with fibronectin (group 3) coated with a RGD-containing peptide or (group 4) coated in a similar way to group 3 but without application of a RGD-peptide, were incubated for 30 min with adult human saphenous vein endothelial cells. After seeding, grafts were exposed to shear stress in an artificial flow circuit. EC attachment after seeding and retention after perfusion was assessed by scanning electron microscopy and image analysis. MAIN RESULTS: Both EC attachment and retention were significantly increased by coating with fibronectin in comparison to uncoated ePTFE. Graft coating with an RGD-peptide lead to the highest increase in EC attachment (30.6% +/- 2.1%) and retention after shear stress (62.9% +/- 7.5%) compared to fibronectin coated (26.0% +/- 3.3%/45.5% +/- 2.1%), uncoated (14.9% +/- 3.1%/13.9% +/- 7.9%) and similar coated ePTFE grafts without application of a RGD-peptide (10.5% +/- 1.1%/6.6% +/- 1.5%). CONCLUSIONS: EC attachment on uncoated ePTFE vascular prostheses is very weak. Our technique of coupling the ePTFE graft surface with cell adhesion promoting RGD-containing synthetic peptides significantly improved this decisive step in endothelial cell seeding of ePTFE grafts.

Adult↗
PubMed1996

Endothelial cell seeding of de-endothelialised human arteries: improvement by adhesion molecule induction and flow-seeding technology.

OBJECTIVES: To assess re-endothelialisation of denuded human arteries by two different seeding techniques using adhesion molecule induction and a dynamic flow-seeding. DESIGN: Prospective, open study. SETTING: University Department of Cardiovascular Surgery. MATERIALS AND METHODS: In the first group (I) segments of human common carotid arteries (n = 4) were balloon-denuded, short-time seeded with cultured adult human venous endothelial cells (EC) and exposed to a mock circulation. In the second group (II) (n = 4), EC were incubated with a synthetic RGD peptide (arginine-glycine-aspartate) prior to seeding with the aim of upregulating the cellular adhesion molecules and increasing EC attachment. In the third group (III) (n = 4), EC were seeded not using the common technique of instillating cells and sequentially rotating the graft but by a dynamic flow application. The percentage of EC-covered luminal surface was assessed by image analysis of scanning electron micrographs. RESULTS: EC attachment was significantly increased in groups II (73%) and III (94%) compared with group I (34%). In group III, a preconfluent monolayer could be established immediately after seeding. One hour of artificial perfusion resulted in no significant EC loss in any of the study groups. CONCLUSIONS: RGD-peptide preincubation improves EC seeding of biological surfaces. Because of accelerated seeding times it may have good potential for clinical applications. The flow-seeding technology may be indispensable if EC seeding of the vascular surface of complete organ systems is required.

Adult↗
PubMed1996

Do long-term results justify bridging to heart transplantation in patients with multi-organ dysfunction?

This retrospective study was performed to determine the influence of multi-organ dysfunction and the type of preoperative hemodynamic support on mortality after heart transplantation. All patients undergoing heart transplantation during a 6 year period were divided into 3 groups: group A patients (n = 110) had stable hemodynamics on oral medication, group B recipients (n = 41) received continuous i.v. catecholamine application, and in group C (n = 21) mechanical hemodynamic support was necessary. In groups B and C elevated serum creatinine and transaminase levels-reflecting renal and hepatic dysfunction-were detected more often and the survival rate was worse during the first six months (A: 85%, B: 71%, C: 52%, p < 0.01). In group C the prognosis of patients with multi-organ dysfunction was significantly worse compared to patients with normal renal and hepatic function (38% vs. 75%; p < 0.01). In recipients surviving for six months, there was no difference in long-term prognosis between the groups studied. It is concluded that heart transplantation in patients with multi-organ dysfunction on invasive hemodynamic support bears a significantly increased risk in the early postoperative period. In view of the current donor shortage the condition of other organs should be improved before transplantation as far as possible, even using long-term mechanical support.

Adult↗
PubMed1996

[MR diagnosis after a Ross operation].

PURPOSE: To determine the ability of MRI to diagnose morphological and functional changes in patients after Ross procedure. MATERIAL AND METHODS: During one year, 5 patients after Ross procedure were studied by MRI. T1-weighted spin-echo sequences in different orientations as well as cine sequences and a VENC sequence were used. RESULTS: In all patients the morphology including the postoperative changes could be visualised by MRI. The cine sequences provided functional information on valvular and ventricular function. VENC-MR yielded an exact quantification of the regurgitant fraction. CONCLUSION: MRI is capable of providing all important diagnostic information in patients after Ross procedure such as valvular and ventricular function and valvular and outflow tract morphology in a single examination.

Adolescent↗
PubMed1996

Positive inotropic effects of the calcium sensitizer CGP 48506 in failing human myocardium.

In trabeculae carneae from failing human myocardium, CGP 48506 increased the force of contraction, which reached 310 +/- 41% of predrug values at 100 mumol/l. Its stereoisomer CGP 48508 did not affect the force of contraction (100 mumol/l). The positive inotropic effect of CGP 48506 was not sensitive to 10 mumol/l carbachol. The positive inotropic effect of CGP 48506 was accompanied by increases in time to peak tension and time of relaxation amounting to 175 +/- 4% and 205 +/- 15% of control, respectively, at 100 mumol/l. CGP 48506 but not CGP 48508 sensitized skinned trabeculae from failing human myocardium to calcium with an EC50 value of 10 mumol/l. However, CGP 48506 and CGP 48508 (up to 300 mumol/l) did not affect the activity of PDE isoenzymes I to IV from failing human myocardium. CGP 48506 is the first inotropic agent with calcium-sensitizing properties in the human heart that has been found to be devoid of inhibitory activity on human cardiac PDE isoenzymes.

1-Methyl-3-isobutylxanthine↗
PubMed1996

[Coronary heart disease and impaired left ventricular function in patients over 80 years of age--is bypass operation justified?].

Between April 1988 and February 1995, 35 patients aged 80 years or older underwent elective coronary artery bypass grafting. Concomitant aortic valve replacement was performed in eight patients. Fifteen patients with moderate to severe left ventricular dysfunction (left ventricular ejection fraction (EF) 20 to 45%) (group I) were compared to 20 patients with an EF > 45% (group II). There were no differences according to age, NYHA classification and associated diseases. Group I patients had significantly more myocardial infarctions compared to group II (1.3 +/- 1.1 vs. 0.5 +/- 0.8; p < 0.05). Also more bypass grafts per patient were used in group I (3.1 +/- 0.9 vs. 2.3 +/- 0.9; p < 0.01). No differences between the groups were observed in the postoperative course. One patient of group II died from multiorgan failure (hospital mortality 2.2%). A follow-up could be performed in 32 of 34 hospital survivors (94%) 12.0 +/- 11.2 months (1-41 months) postoperatively. There was one non-cardiac death in each group. All hospital survivors improved by at least one NYHA functional class. Actuarial survival at 3 years is 91% in both groups. In patients aged 80 years or older with or without left ventricular dysfunction coronary artery bypass surgery can be performed with an acceptable risk and a functional benefit. Thus, elective operations should be performed in this age group despite left ventricular dysfunction.

Aged↗
PubMed1996

Cytomegalovirus induces interstitial lung disease in allogeneic bone marrow transplant recipient rats independent of acute graft-versus-host response.

Interstitial lung disease (ILD) after allogeneic bone marrow transplantation (BMTx) is an important clinical problem in terms of diagnosis, therapy, and pathogenesis. Graft-versus-host disease (GvHD) and cytomegalovirus (CMV) infection seem to be major risk factors for ILD, but their role in the pathogenesis is not well established. We previously reported CMV-induced ILD in allogeneic bone marrow recipient rats, which was prevented by antiviral drug treatment. In this paper, we describe the pathology of ILD in allogeneic bone marrow transplant recipient rats and the relation of ILD with CMV infection and GvHD. Brown Norway rats received an allogeneic (Lewis) BMTx and rat CMV infection, after an allogeneic (Lewis) lung transplantation and immunosuppression. CMV infection was recorded by the amount of infectious virus and viral antigens in the lung. ILD was monitored by the presence of diffuse histopathologic changes in the alveolar septal wall. GvHD was scored by the relative splenic weights and the presence of perivascular infiltrates in the lung. Cells expressing CMV antigens were more numerous in the alveolar septa of the allogeneic recipient lungs than in the syngeneic donor lungs (p < 0.05). The high viral load in the recipient lung of allogeneic BMTx recipient rats was accompanied by diffuse ILD, marked by extensive microvascular damage and congestion of the alveolar septa. ILD was observed neither in the syngeneic donor lung nor in both lungs of mock-infected animals. GvHD was not observed in rat-CMV-infected or in mock-infected animals. Our results indicate that CMV induces microvascular damage, resulting in ILD. This process is independent of GvHD.

Animals↗
PubMed1996

Enhancement of cytomegalovirus infection and acute rejection after allogeneic lung transplantation in the rat: virus-induced expression of major histocompatibility complex class II antigens.

BACKGROUND: Cytomegalovirus infection is considered a major complication after lung and heart-lung transplantation because it can trigger acute and chronic rejection. The potential mechanisms of lung transplant rejection induced by viral infection include the upregulation of expression of major histocompatibility complex antigens. To address this question, a model of rat cytomegalovirus infection and acute lung transplant rejection was established. METHODS: Lewis inbred strain rats received syngeneic (n = 25) or allogeneic (Brown-Norway inbred rat strain, n = 38) orthotopic left-side lung transplants. Triple-drug immunosuppression with cyclosporin A, methylprednisolone, and azathioprine was given from postoperative days 1 through 10. Rat cytomegalovirus was inoculated intraperitoneally on postoperative day 3. Two control groups, those infected with cytomegalovirus (n = 15) and those without rat cytomegalovirus infection (n = 6) were treated with identical immunosuppressive regimens. Animals were sacrificed on postoperative days 11, 15, 18, 20, and 25. The salivary glands and both lungs were removed for pathologic and immunohistochemical investigations. RESULTS: All animals inoculated with rat cytomegalovirus developed systemic viral infection on or after postoperative day 11, as confirmed by an assay of plaque-forming units and immunohistologic examination. Cytomegalovirus-induced expression of major histocompatibility complex class II antigens on vascular endothelial cells was seen in the nontransplanted lungs of rats, but no major histocompatibility complex class II antigens were detected on noninfected, nontransplanted lungs. Cytomegalovirus infection also was found to enhance major histocompatibility complex class II antigen expression on pneumocytes and leukocytes in rats. Acute rejection occurred in allogeneic transplants from postoperative days 15 through 25. The expression of class II antigens on endothelial cells, pneumocytes, and leukocytes was further enhanced during the course of allograft rejection in the cytomegalovirus-infected rats compared with the noninfected controls. In cytomegalovirus-positive rats, the rejection grade was higher than that in cytomegalovirus-negative rats on postoperative days 15 through 18. CONCLUSIONS: Our results indicate that cytomegalovirus induces and enhances the expression of major histocompatibility complex class II antigens on endothelial cells, pneumocytes and leukocytes. Upregulation by cytomegalovirus infection may trigger or promote acute rejection by alloantigenic T-lymphocyte stimulation after lung transplantation. By this mechanism it may strongly influence the long-term course of lung transplant rejection.

Acute Disease↗
PubMed1996

[Exogenous adenosine in cardioplegia].

The nucleoside adenosine is used clinically for the treatment of paroxysmal atrioventricular junctional tachycardia. Surgically oriented experimental studies indicate an improvement of myocardial protection when adenosine is administered as an adjunct to cardioplegic protection. This regards both postischemic functional recovery and the regeneration of myocardial energy-rich phosphates. However, as yet it remains to be determined which of the various effects of adenosine is truly protective. Likewise it is still unclear if the beneficial effects of "ischemic preconditioning" may be simulated by administration of adenosine. Current knowledge about this substance warrants careful evaluation of its protective capabilities in clinical studies during open-heart surgery.

Adenosine↗
PubMed1996

[Is heart surgery in over 80-year-old patients justified?].

Coronary artery bypass grafting and/or aortic valve replacement was performed in 68 patients aged 80 or older. These patients were compared to 743 patients younger than 80 years. In octogenerians cardiac surgery can be performed with an acceptable risk and a functional benefit.

Aged↗
PubMed1996

[Simultaneous operations of the carotid bifurcation and coronary vessels in moderate systemic hypothermia].

Comorbidity of coronary heart disease and carotid stenosis raises the question of surgical stratification. A simultaneous approach of carotid endarterectomy and coronary revascularization, both under conditions of moderate hypothermic extracorporeal circulation, was applied in 48 patients. Considering the complexity of the procedures required the 30-day mortality (2.1%) and perioperative incidence of permanent stroke (2.1%) or myocardial infarction (0%) appeared to be comparably low.

Aged↗
PubMed1995

Intramural hemorrhage of the thoracic aorta. Diagnostic and therapeutic implications.

BACKGROUND: Intramural hemorrhage (IMH) was recently identified at necropsy and anecdotally in vivo as a unique aortic syndrome (without entry and with no flap-like intraluminal component, such as overt aortic dissection). However, little is known about diagnosis, prognosis, and outcome of IMH. METHODS AND RESULTS: Between 1983 and 1993, 360 patients from two medical centers with clinical indications of aortic dissection were prospectively evaluated; they presented to the emergency department a median of 3.5 hours after onset of back or chest pain or other suggestive symptoms. Among 195 patients with aortic syndromes, 25 patients (12.8%) were diagnosed to have IMH of the thoracic aorta with no evidence of a primary intimal tear, flap, or overt dissection by multiple noninvasive imaging modalities, including magnetic resonance imaging (n = 12), contrast-enhanced computed tomography (n = 14), and transesophageal echocardiography (n = 3) in random order. There were 16 men and 9 women with a median age of 56 +/- 13 years (range, 15 to 80 years). Arterial hypertension was present in the majority (84%), and Marfan's syndrome was present in 3 patients (12%). IMH was diagnosed within 4 days of hospital admission (median, 2.5 hours). IMH involved the ascending aorta (type A) in 12 cases (48%), the aortic arch in 2 (8%), and the descending aorta (type B) in 11 cases (44%); imaging results were validated by crossmatching with intraoperative, pathomorphological, and/or angiographic findings. IMH was 8.5 +/- 5 cm in length and 2.0 +/- 1.2 cm in aortic wall thickness. Aortic regurgitation and pericardial and mediastinal effusion were present in 5 of 12 patients (42%) with type A IMH and 2 of 11 patients (18%) with type B IMH. IMH progression to overt dissection, rupture, and/or acute tamponade occurred in 8 of 25 patients (32%) within 24 to 72 hours, indicating the need for urgent intervention. The 30-day mortality rate of IMH afflicting the ascending aorta was 80% (4 of 5 cases) with medical treatment (sedation and blood pressure control) versus no mortality in 7 cases with early surgical repair (P < .01); after 1 year, 71.4% of surgically treated patients were alive versus 20% in the medical group (P < .05). IMH of the aortic arch resulted in an early mortality of 50% (1 of 2 patients) with medical treatment. In IMH confined to the descending thoracic aorta, survival with medical treatment was not different from surgical therapy; there was 1 early death among 6 patients with medical therapy and none out of 5 patients with surgery (P = NS). At 1-year follow-up, medical and surgical therapy groups had survival rates of 80% and 83%, respectively (P = NS). CONCLUSIONS: IMH is associated with a clinical profile and prognosis similar to classic dissection and may be considered an ominous precursor of overt aortic dissection. Tomographic noninvasive imaging ensures rapid, nontraumatic diagnosis of IMH. The outcome of IMH of the ascending aorta appears favorable only with immediate surgical repair.

Adolescent↗
PubMed1995

[Fatal Aspergillus sepsis following orthotopic heart transplantation].

In a 64-year-old man heart transplantation had been performed for ischaemic heart disease. 7 months later severe vascular disease in the transplant necessitated a second transplantation. Both procedures had been performed under immunosuppression (cyclosporine, azathioprine, prednisolone, antithymocyte globulin), with a subsequent prednisolone maintenance dose of 10 mg daily. At first there were no complications, but 31 days after the re-transplantation atrial flutter developed. Although this was quickly terminated by drugs, circulatory failure set in. Because of signs of infection (white blood cell count 29,800/microliters, 17% stab cells, C-reactive protein 24 mg/l) broad-spectrum antibiotics were administered, but without response. As a trial anti-rejection treatment was started (prednisolone 250 mg daily: antithymocyte globulin 100 mg daily for 4 days). When cytomegalovirus (CMV) infection was demonstrated, ganciclovir and CMV hyperimmunoglobulin were administered and slow improvement was noted. The finding of Aspergillus in tracheal secretion was interpreted as apathogenic colonization. The patient died from cardiorespiratory failure 57 days after the second transplantation. Autopsy revealed Aspergillus sepsis.

Aspergillosis↗
PubMed1995

Protection of the chronic hypoxic immature rat heart during global ischemia.

The benefit of cardioplegic cardiac arrest for the protection of immature myocardium is controversial. We therefore investigated the efficacy of (1) topical hypothermia alone, (2) slow cooling by coronary perfusion hypothermia, and (3) cardioplegic cardiac arrest for the protection of isolated immature rats hearts (28 days) during 8 hours of global ischemia at 10 degrees C. The study was conducted in hearts from rats that were kept hypoxemic by lifelong exposure to simulated high altitude. Left ventricular function, endothelial function, the metabolic status, and the extent of myocardial injury were all assessed. Topical hypothermia provided superior protection in hypoxic hearts, with recovery of the maximum developed left ventricular pressure by 70.6% +/- 18.0% (mean +/- standard deviation) of its preischemic value (p < 0.01 versus slow cooling and versus cardioplegic protection). The same pattern of recovery was observed among control hearts. The degree of recovery of endothelial function after sole topical hypothermia measured 54% +/- 36% in hypoxic hearts and 62% +/- 37% in control hearts, but was not recordable in any of the other groups. Creatine kinase leakage and the myocardial high-energy content did not differ significantly among any of the groups. Rapid cooling by topical hypothermia alone provides superior protection in chronic hypoxic, immature rat hearts versus the protection conferred by slow cooling. St. Thomas' Hospital cardioplegic solution II does not afford additional protection. Endothelial injury caused by cold asanguineous perfusates, including cardioplegia, interferes with the recovery of vascular function, which, in turn, may limit mechanical function.

Adenosine Triphosphate↗