PubMed Health⌕ Search

Biomedical subjects

W Harringer

Publications and source records attributed to W Harringer.

At least 55 records · Page 3Linked to original sources
PubMed1999

Lung transplantation--10-year experience.

OBJECTIVE: The experience at our institution with various forms of lung transplantation (heart-lung, double lung and single lung) from December 1987 to September 1998 is reviewed and discussed. METHODS: During this decade, 282 procedures (46 heart-lungs (HLTx), 142 double lungs (DLTx) and 94 single lungs (SLTx)) have been performed in 258 patients (140 male, 118 female; age: 38 +/- 13 years). Major indications included pulmonary fibrosis (n = 73), obstructive lung disease (n = 55), cystic fibrosis (n = 48), primary pulmonary hypertension (n = 36), secondary pulmonary hypertension (majority Eisenmenger's syndrome) (n = 30), and retransplantation (n = 24). RESULTS: Early postoperative mortality (<90 days) was 13.9% (n = 36). The 1-, 3-, and 5-year survival rates in all recipients was 77, 70 and 63%, respectively. There was no significant difference in 1-year survival rates between the different procedures (HLTx: 78%, DLTx: 77%, SLTx: 77%). Significantly better 1-year survival was achieved in patients with cystic fibrosis (89%), pulmonary fibrosis (81%), obstructive lung disease (74%), and Eisenmenger's syndrome (83%) when compared to patients with primary pulmonary hypertension (55%). Survival rates remained unchanged during this period despite expanding indications during the last years. Causes of death in 90 recipients (HLTx: n = 19, DLTx: n = 37, SLTx: n = 34) included sepsis (n = 42), obliterative bronchiolitis (n = 28), cardiac failure (n = 5), and early allograft dysfunction (n = 2). Freedom from bronchiolitis obliterans syndrome (BOS) (>stage I ISHLT) was 80% at 1 year and 45% at 5 years. CONCLUSIONS: Lung transplantation offers a true therapeutic option with good early and midterm results. Yet, chronic graft dysfunction represents a major obstacle for long-term benefit of this procedure.

Adolescent↗
PubMed1999

Valve-sparing repair after aortic root dissection following heart transplantation.

We describe the case of a 56-year-old male who presented with a Stanford type A dissection limited to the donor aorta 25 days after orthotopic heart transplantation. Transesophageal echocardiography revealed a newly developed aortic regurgitation grade III and a typical intimal tear 1 cm above the commissures. Surgical therapy included replacement of the ascending aorta with an aortic allograft and implantation of the native aortic valve inside the allograft as a modified David procedure.

Aortic Dissection↗
PubMed1999

Exogenous surfactant improves survival and surfactant function in ischaemia-reperfusion injury in minipigs.

Reperfusion injury is the major cause of early morbidity and mortality after lung transplantation. This complication has been experimentally linked to dysfunction of pulmonary surfactant. Therefore, the hypothesis that reperfusion injury might be preventable by exogenous surfactant treatment was tested. Left lungs of minipigs were exposed to 120 min of ischaemia, and the lungs were then reperfused for up to 7 h. Animals were divided into a control group and a surfactant group (n=5 each). The surfactant group received 50 mg x kg(-1) Alveofact intrabronchially via a bronchoscope at the beginning of the ischaemic period. Bronchoalveolar lavage was performed at baseline before ischaemia and 90 min after reperfusion. Surfactant treatment significantly improved short-term survival. Pulmonary vascular resistance increased markedly in control animals leading to right heart failure and death within 3 h after reperfusion whereas the surfactant-treated animals survived the 7 h observation period. After reperfusion, alveolar accumulation of neutrophils and exuded proteins was present in both groups to the same extent. Surfactant activity after reperfusion deteriorated markedly in the control group but was preserved in the surfactant group. In conclusion, early surfactant treatment alleviates the deterioration of surfactant function and improves survival in this minipig model of ischaemia-reperfusion injury.

Animals↗
PubMed1999

Inhaled nitric oxide as a prophylactic treatment against reperfusion injury of the lung.

BACKGROUND: Inhaled Nitric Oxide (NO) has been found to be effective in clinical treatment of reperfusion injury after lung transplantation. This study was designed to determine a possible prophylactic role to reduce severe reperfusion injury. METHODS: In 12 minipigs the left lung was selectively perfused with cold Euro-Collins solution. After 90 minutes of warm ischemia the lungs were reperfused and the contralateral pulmonary artery and main bronchus clamped. Hemodynamic and respiratory parameters were monitored for 7 hours. 6 animals were used as controls. 6 pigs formed the NO group and were ventilated continuously with 40 ppm nitric oxide (NO) starting 30 minutes prior to reperfusion. RESULTS: In the control group right heart failure developed within 1.9 +/- 0.8 hours of reperfusion. Lung compliance was significantly reduced. A significant increase of pulmonary vascular resistance (PVR) was found. All animals of the NO group survived the reperfusion period of 7 hours. PVR was decreased compared to controls (p = 0.03). AaDO2 was lower, but not significantly different. The dynamic compliance of the lung was significantly higher (p = 0.007) in the NO group. CONCLUSIONS: The prophylactic institution of inhaled NO reduces reperfusion injury of the lung. Short-term use of inhaled NO should be adopted as a prophylactic agent after transplantation of lungs preserved in Euro-Collins solution.

Administration, Inhalation↗
PubMed1999

Ten year survival after heart transplantation: palliative procedure or successful long term treatment?

OBJECTIVE: To investigate the long term outcome and prognostic factors after heart transplantation. SETTING: University hospital. SUBJECTS: 120 heart transplant patients (98 male, 22 female; underlying disease: dilated cardiomyopathy in 69, coronary artery disease in 42, miscellaneous in nine) who had undergone heart transplantation between October 1984 and October 1987. Immunosuppressive treatment was comparable in all patients and rejection episodes were treated in a uniform manner. METHODS: Functional status, quality of life, and potential predictors for long term survival were investigated. RESULTS: Actuarial survival rates were 65% at five years and 48% at 10 years; 58 patients survived > 10 years. The major causes of death were cardiac allograft vasculopathy (39%), acute rejection (18%), infection (11%), and malignancy (11%). Long term survivors had good exercise tolerance assessed by the New York Heart Association classification: 47 (81%) in grade I/II; 11 (19%) in grade III/IV. Echocardiography showed good left ventricular function in 48 patients. On angiography, severe allograft vasculopathy was present in only 16 patients (28%). Renal function was only slightly impaired, with mean (SD) serum creatinine of 148.5 (84.9) micromol/l. Multiple potential predictors of long term survival were analysed but none was found useful. CONCLUSIONS: Heart transplantation represents a valuable form of treatment. Survival for more than 10 years with a good exercise tolerance and acceptable side effects from immunosuppression can be achieved in about 50% of patients.

Adult↗
PubMed1999

Site of pleural drain insertion and early postoperative pulmonary function following coronary artery bypass grafting with internal mammary artery.

STUDY OBJECTIVES: Coronary artery bypass graft (CABG) surgery using the left internal mammary artery (LIMA) impairs postoperative pulmonary function. We studied the changes in pulmonary function and subjective pain relative to the site of chest tube insertion. DESIGN: Thirty patients undergoing CABG surgery using the LIMA were randomized into two groups. Group A (n = 15) received a left chest tube inserted from the midline (subxyphoid). Group B (n = 15) had a tube placed in the sixth intercostal space at the anterior axillary line. All of the patients underwent bedside pulmonary function testing preoperatively and on postoperative days (PODs) 1, 3, and 5. Pain sensation was quantified by a standardized score (1 to 10). RESULTS: A significant impairment of pulmonary function parameters was observed in both groups until POD 5. For group A, the decline in percent predicted (+/-SD) in the vital capacity (VC) from before surgery to POD 5 was, respectively, 92.3+/-30.6% to 56.9+/-12.6% (p < 0.001). For group B, the decline in the VC was from 88.0+/-18.2% to 55.5+/-14.8% (p < 0.001). The FEV1 declined concomitantly in group A from 86.2+/-18.2% to 50.8+/-12.1%, and in group B from 83.5+/-16.4% to 53.9+/-12.5% (p < 0.001). On POD 1, a significantly lower decrease in the VC was measured in group A than in group B, respectively: 45.3+/-15.5% vs 28.6+/-8.7% (p < 0.001). A significantly lower decrease in the FEV1 was also seen in group A than in group B, respectively: 36.9+/-12.9% vs 28.0+/-10.6% (p < 0.05). Pain experienced during deep inspiration was also significantly less in group A than in group B, respectively: 1.2+/-1.1 vs 2.5+/-0.9 (p < 0.01). CONCLUSIONS: Subxyphoid insertion of the pleural drain leads to a significantly lower impairment of pulmonary function and less subjective pain than insertion at the intercostal position. The drainage of the left pleural space is equally effective with both techniques.

Aged↗
PubMed1999

[Lung transplantation in Hanover: an interim balance-sheet after ten years].

BACKGROUND: We reviewed our experience with various forms of lung transplantation (heart-lung [HLTx], bilateral lung [BLTx] and single lung [SLTx]) from December 1987 to September 1998 at Hannover University. PATIENTS: In 258 patients 282 procedures (46 HLTx, 142 BLTx and 94 SLTx) were performed. Major indications were pulmonary fibrosis (n = 73), obstructive lung disease (n = 55), cystic fibrosis (n = 48), primary pulmonary hypertension (PPHT, n = 36), secondary pulmonary hypertension (n = 30) and retransplantation (n = 24). RESULTS: The 1-, 3- and 5-year survival rates in all 258 recipients were 77%, 70% and 63% respectively. Significantly better 1-year survival was noted in patients with cystic fibrosis (90%), pulmonary fibrosis (81%), obstructive lung disease (71%) and secondary pulmonary hypertension (83%) when compared to patients with primary pulmonary hypertension (58%). There was no significant difference in actuarial 1-year survival rates between the different procedures (HLTx 78%, BLTx 77%, SLTx 77%). Bronchiolitis obliterans syndrome (BOS) proved to be the major obstacle for long term survival. Actuarial freedom from BOS was 80% at 1 year and only 45% at 5 years. Various treatment strategies including augmentation of immunosuppression could only temporarily halt the deterioration of lung function in the majority of patients with BOS. CONCLUSIONS: Lung transplantation provides a true therapeutic option for patients with endstage lung disease. However, improved long term outlook will depend on a better understanding and treatment of bronchiolitis obliterans.

Adolescent↗
PubMed1998

[Aortic valve insufficiency in aneurysms of the ascending aorta: functional results following valve-sparing reconstruction].

BACKGROUND AND OBJECTIVE: Changes in geometry of the aortic root, especially a dilatation of the sinotubular junction, are the major causes of aortic valve regurgitation in ascending aortic aneurysm. In valves without structural defect, a valve sparing aortic root reconstruction may be a therapeutic option. Aim of this study was the assessment of functional results, in the early postoperative, and during follow-up, in a large patient cohort from one centre. PATIENTS AND METHODS: Between July 1993 and March 1998, a total of 48 valve sparing operations were performed at Hannover Medical School. Mean age of patients (34 males, 14 females) was 47.4 +/- 19 years. In a prospective design clinical, and echocardiographic examinations were performed pre-, intra and early postoperatively as well as 3.6 and then every 12 months during follow-up. Structural valve changes, systolic pressure gradients as well as the degree of diastolic regurgitation were evaluated. RESULTS: Aortic root reconstruction was successful in all patients; none died perioperatively. Extension of the underlying disease to the aortic arch was present in eleven, acute and chronic dissection of the ascending aorta (type A) in two and three patients, respectively. Echocardiographic follow-up over a mean period of 25.1 +/- 18.3 months (cumulatively 1204 months) revealed stable valve function in 41 patients without (n = 30) or with a minimal (n = 11) regurgitation. In three patients moderate valve regurgitation (grade 2) was observed, three patients (6.3%) had to be reoperated because of a progressive valve failure. Thromboembolic or bleeding complications were not observed. CONCLUSIONS: Valve sparing aortic root reconstruction is a promising alternative to the composite replacement of the ascending aorta. Low perioperative morbidity and mortality rates as well as favourable functional results were demonstrated. Long-term anticoagulation can be avoided. Long-term follow-up will be necessary to assess the definitive role of this new surgical approach.

Adult↗
PubMed1998

Cardiac valve endothelial cells: relevance in the long-term function of biologic valve prostheses.

OBJECTIVE: For reasons that are still unclear, biologic heart valve prostheses undergo degeneration after implantation. We studied the possible role of the immune system in this process. METHODS: We examined the expression of immunologically relevant molecules by human cardiac valve endothelium in situ and in vitro and studied re-endothelialization of implanted allogeneic and xenogeneic valvular surfaces using explanted bioprostheses and valves obtained from donor hearts at cardiac retransplantation. RESULTS: We demonstrate that human cardiac valve endothelial cells express molecules capable of initiating immune responses and might therefore play a role in the degeneration of viable cardiac valve prostheses. Also, we show evidence of re-endothelialization on the surfaces of xenografts and allografts but not on valves obtained from previously transplanted hearts. CONCLUSION: Inasmuch as valves from previously transplanted hearts seem to be free from degeneration, we conclude that reduction of the immunogenicity of allograft valve prostheses by HLA matching or immunosuppressive treatment might further improve long-term results after allograft valve replacement.

Antigens, CD↗
PubMed1998

Lung transplantation for cystic fibrosis--a single center experience over 8 years.

OBJECTIVE: Colonization of the lung and mediastinal lymph nodes with multi-resistant bacteria, diabetes and malnutrition represent potential risk factors for lung transplantation in cystic fibrosis. We therefore reviewed our experience in this patient population. METHODS: Between December 1988 and March 1997, 219 lung and heart-lung transplantations were performed at our institution. Of these, 39 procedures were done in 35 patients with cystic fibrosis. All candidates (mean age 26 years) were oxygen dependent (preoperative mean PO2: 44.8 +/- 9.1 Torr, preoperative mean PCO2: 53.4 +/- 10.5 Torr, one patient on respirator). Of the primary operations, 34 were performed as bilateral sequential lung transplants, one as a heart-lung transplantation. RESULTS: Mean duration on respirator for survivors was 3.1 (1-12) days, mean ICU and hospital stay were 4.7 (1-13) and 28 (12-79) days, respectively. The 3-month mortality rate was 5.7% (two patients died due to acute graft failure on days 36 and 73). Other causes of death in the follow-up were cerebral bleeding (one patient) and chronic graft failure (three patients). The survival rates were 91% at 1 year, 83% at 3 years and 76% at 5 years. In eight patients, a bronchiolitis obliterans syndrome (BOS) developed (in four cases grade 3). The freedom of BOS (grade 1 or more) at 1, 3 and 5 years was 87, 79 and 55%, respectively. Four retransplantations were performed. Of the 29 patients alive, only seven are physically limited. CONCLUSION: Bilateral lung transplantation for cystic fibrosis allows for acceptable early- and long-term results. Postoperative survival is not impaired by infection, diabetes and malnutrition. Long-term functional outcome seems to be comparable to lung transplantation in patients without infectious pulmonary disease.

Adult↗
PubMed1998

ON-X bileaflet valve in aortic position--early experience shows an improved hemodynamic profile.

BACKGROUND: Despite considerable progress during the last decades, mechanical heart valves still have significant disadvantages in performance compared to native valves. To optimize the hemodynamic profile, a new mechanical bileaflet valve (ON-X) was developed and introduced in 1997. It was the aim of this study to assess the feasibility, safety, and the early postoperative hemodynamics with this new valve in vivo. METHODS: We analyzed 19 patients (11 male, 8 female; 63.2 +/- 8.2 years; aortic stenosis: n = 13; aortic incompetence: n = 2; combined aortic lesion: n = 2), undergoing aortic valve replacement with this prosthesis (valve size 19 mm: n = 1; 21 mm: n = 6; 23 mm: n = 8; 25 mm: n = 4; additional CABG: n = 4). In addition to intraoperative pressure gradient measurements, echocardiography was performed early postoperatively and after 3 months, evaluating pressure loss, effective orifice area, and regression of left-ventricular hypertrophy. RESULTS: No major perioperative complications were observed. The echocardiographic evaluation demonstrated a significantly increased effective orifice area and lower transvalvular gradients in all valve sizes compared with literature values for the St. Jude Medical prosthesis. Effective regression of left-ventricular hypertrophy (-23.6%) was observed over the first three months. CONCLUSIONS: These preliminary data confirm the favorable hemodynamic characteristics of the ON-X valve as compared to standard bileaflet designs. Implantation was feasible and safe, and no major postoperative complications such as thrombembolic events were observed.

Aortic Valve↗
PubMed1998

Prediction of the onset of atrial fibrillation after cardiac surgery using the monophasic action potential.

OBJECTIVE: To show that the monophasic action potential (MAP) recorded continuously from human epicardium may be used to predict the imminent onset of atrial fibrillation or flutter (AF) following surgery, thus allowing prophylactic treatment to be started. PATIENTS: 22 patients (14 male, 8 female; mean (SD) age 64 (12) years) undergoing aortic valve replacement. SETTING: Tertiary referral centre. METHODS: Over a mean observation period of 8 (2.7) days (range 4 to 14), nine episodes of AF were seen in six patients. Before AF, specific and significant alterations of the MAP morphology were observed. In seven of nine episodes the MAP shortened (25 (4)% 60 minutes before AF), developed a triangular shape, and the plateau amplitude decreased from 5.3 (1.2) to 2 (0.2) mV. In the two remaining episodes the beat to beat variability of cycle length and MAP duration at 90% repolarisation (MAPd90) increased significantly from 24 (7) ms and 12 (8) ms (24 hours before AF) to 137 (27) ms and 56 (11) ms (30 minutes before AF) respectively. AF was successfully treated by the administration of sotalol in three cases and by a combination of verapamil and digoxin in a further four. Previously observed changes of MAPd90 and MAP morphology regressed after conversion to sinus rhythm. CONCLUSIONS: The continuous and intermediate term recording of the MAP from atrial epicardium appears to be a valid tool for detecting imminent AF after cardiac surgery with a high sensitivity (99%) and specificity (88%). Optimised antiarrhythmic treatment may thus be given selectively for prophylaxis.

Action Potentials↗
PubMed1997

Off-bypass coronary bypass grafting via minithoracotomy using mechanical epicardial stabilization.

BACKGROUND: Minimally or less invasive surgical coronary revascularization has gained increasing interest along with new techniques and devices designed for easier and safer procedures. Until recently, it appeared questionable whether grafting techniques with avoidance of cardiopulmonary bypass techniques would allow adequate results compared with conventional techniques using cardioplegic arrest. METHODS: Since June 1996, minimally invasive direct coronary artery bypass grafting procedures without cardiopulmonary bypass were intended in 24 patients (19 male, 5 female; age, 60.5 +/- 10.5 years) applying a special system (CardioThoracic Systems, Inc) for internal mammary artery access and epicardial surface stabilization approaching through an anterolateral minithoracotomy. Neither video-assisted preparation nor additional pharmacologic stabilization was applied. Concomitant risk factors and associated comorbidity were frequent. RESULTS: The procedure was completed in 23 patients, grafting the left anterior descending coronary artery (n = 21) or diagonal branches (n = 3, 1 sequential) as scheduled. In 1 case with internal mammary artery dissection, cardiopulmonary bypass and sternotomy became necessary. Simultaneous carotid endarterectomy was performed in 1 patient. There were two episodes of intraoperative ventricular fibrillation; no other major complications occurred. Postoperative evaluation was obtained in 16 patients (15 by angiography, 1 by Doppler echocardiography) so far and revealed adequate graft function and patency. CONCLUSIONS: Using specially designed instruments for internal mammary artery access and epicardial surface stabilization, minimally invasive direct coronary artery bypass grafting procedures via a minithoracotomy avoiding cardiopulmonary bypass techniques may be applied safely and successfully, even in increased risk constellations.

Cardiopulmonary Bypass↗
PubMed1997

Influence of bicaval anastomoses on late occurrence of atrial arrhythmia after heart transplantation.

BACKGROUND: The standard technique for orthotopic heart transplantation includes right and left atrial anastomoses, which potentially disturb the integrity of the donor atria. Consequently, electrophysiologic abnormalities such as atrial flutter and fibrillation may occur even late after heart transplanation. METHODS: Over a 3-year period, 39 heart transplantations were performed using a standard right atrial anastomosis (group A), and 40 were done using bicaval anastomoses (group B). In each group, data of 30 consecutive patients with a minimum follow-up of 9 months were reviewed retrospectively to assess the incidence of atrial arrhythmia after hospital discharge. RESULTS: Early postoperatively, there was no difference in the duration of temporary pacemaker requirement and incidence of permanent pacemaker implantation (group A, 7%; group B, 7%; not significant) between the two groups. In 12 patients in group A (40%), 16 episodes of atrial flutter and fibrillation were detected 20 to 205 days after heart transplantation. In group B, 1 patient (4%) suffered from atrial fibrillation on day 116 after the operation (p < 0.001). CONCLUSIONS: Preservation of the integrity of the right donor atrium by construction of bicaval anastomoses results in a significantly decreased incidence of atrial flutter and fibrillation after heart transplantation when compared with the standard technique.

Adult↗
PubMed1996

Therapy for lung failure using nitric oxide inhalation and surfactant replacement.

Nitric oxide inhalation and surfactant replacement therapy are relatively new concepts in the treatment of respiratory failure due to hypoxia and reperfusion injury after lung transplantation. We report on a patient in whom reperfusion injury of the lung developed after resuscitation and implantation of a biventricular assist device for sudden cardiac arrest. Lung failure developed within 12 hours after implantation of the biventricular assist device. Lung function was reestablished using combined therapy of nitric oxide and surfactant. Heart transplantation was performed successfully thereafter. This case indicates the potential role of a combined therapy of nitric oxide and surfactant in acute hypoxic lung failure.

Adult↗