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Biomedical subjects

W Harringer

Publications and source records attributed to W Harringer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Effects of minimal invasive coronary artery bypass on pulmonary function and postoperative pain.

BACKGROUND: Minimally invasive direct coronary artery bypass (MIDCAB) requires substantially smaller incisions than conventional coronary artery bypass grafting (CABG). We investigated whether this fact may lead to less postoperative pain and improved pulmonary function. METHODS: Preoperative and postoperative (days 1, 3, and 5) pulmonary function and postoperative pain were assessed in 15 patients undergoing MIDCAB (group A) by using a standardized score and were compared with 15 patients admitted for CABG (group B). RESULTS: Total operation time (140 minutes versus 189 minutes; p<0.001) and duration of mechanical ventilation (300 minutes versus 840 minutes; p<0.001) were significantly less in group A. Pulmonary function was comparable between the 2 groups on postoperative day 1 (POD 1). Vital capacity was significantly greater in group A on POD 3 (59.7% versus 40.6%; p<0.001) and on POD 5 (74.4% versus 53.9%; p<0.001). Similar results were found for forced expiratory volume in 1 second (group A versus B on POD 3: 56.3% versus 42.2%; p<0.05; and on POD 5: 68.4% versus 55.5%; p<0.01). Postoperative pain was significantly higher in group A (POD 1: score 5.5 versus 3.6; POD 3: 4.0 versus 2.9; p<0.01). CONCLUSIONS: MIDCAB procedures lead to better preservation of pulmonary function compared with conventional CABG despite greater postoperative pain.

Aged↗
PubMed2000

Capture of particulate emboli during cardiac procedures in which aortic cross-clamp is used. International Council of Emboli Management Study Group.

BACKGROUND: Previous studies have shown that atheroemboli are associated with neurologic complications following cardiac operation. Additionally, it has been demonstrated that embolization is closely related to the application and removal of ascending aortic cross-clamps. METHODS: A prospective registry of 304 patients was initiated to describe patient selection, procedures, particulate capture, and clinical outcomes after intraaortic filtration in patients undergoing cardiac surgical procedures with cardiopulmonary bypass and median sternotomy. Prior to the removal of the cross-clamp, the intraaortic filter (EMBOL-X Inc, Mountain View, CA) was deployed and left in place until the patient was weaned from extracorporeal circulation. Upon removal, filters were fixed in formalin and shipped to a core laboratory for examination. RESULTS: Mean patient age was 68 years (range 25 to 88 years), 40% had ascending aortic calcification, 59% of the procedures were coronary artery bypass grafting (CABG), 20% were valve replacement or repair, and 12% were a combination of CABG and valve surgery. Aortic cross-clamps were used in nearly all cases (302 of 304 patients); partial clamps were used in 84% of the CABG procedures. To date, 243 filters have been examined. Sixty-two percent of the filters analyzed revealed fibrous atheroma, 2% grumous atheroma, and 6% epiaortic debris. Platelet and fibrin strands were found in 52% of the filters and 22% contained evidence of thrombus or red blood cells. CONCLUSIONS: These findings from the International Council of Emboli Management Registry confirm that particulates are released during cardiac surgical procedures using the aortic cross-clamp. Continued observational and randomized studies are necessary to confirm the clinical relevance of particulate extraction.

Adult↗
PubMed2000

Mini-sternotomy for off-pump coronary artery bypass grafting.

The number of off-pump coronary artery bypass grafting procedures without cardiopulmonary bypass is steadily increasing. We report on a new, minimally invasive surgical approach for off-pump coronary revascularization in multivessel disease. A distal sternotomy is performed to gain access to the left and right internal thoracic arteries and to reach the left anterior descending coronary artery, diagonal branches, and right coronary artery for off-pump revascularization.

Coronary Artery Bypass↗
PubMed2000

Effects of sildenafil on cAMP and cGMP levels in isolated human cavernous and cardiac tissue.

OBJECTIVES: To further investigate the mechanism of action of sildenafil, a selective inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase 5 (PDE5), that has been proved to be effective in the treatment of male erectile dysfunction. We assessed the effects of sildenafil on the in vitro formation of cGMP and cyclic adenosine monophosphate (cAMP) in isolated human corpus cavernosum and cardiac muscle. METHODS: Isolated segments of human corpus cavernosum and cardiac muscle were exposed to increasing concentrations of sildenafil. The dose-dependent accumulation of cGMP and cAMP was determined in the tissue samples by means of radioimmunoassays. Responses of the isolated tissue preparations to sildenafil were compared with those obtained with the reference compounds sodium nitroprusside, forskolin, and milrinone. RESULTS: In the concentration range 0.01 to 1 microM, there was only a minor effect of sildenafil on cGMP levels in isolated human cavernous and cardiac tissues. In contrast, sildenafil was found to increase cAMP significantly in both cavernous and cardiac tissue in physiologic and supraphysiologic concentrations. The stimulation of cAMP by sildenafil was more pronounced in cavernous than in cardiac tissue. Concentrations of cGMP in the cardiac strips were unaltered by milrinone; cAMP was stimulated starting at a concentration of 0.05 microM. In the range of 0.1 to 1.0 microM, the in vitro effect of sildenafil on cAMP levels in the cardiac samples was almost equivalent to that of milrinone. CONCLUSIONS: Our findings provide a potential mechanism for the cardiovascular side effects that have been reported with sildenafil use, highlighting the fact that a "cross-talk" between cGMP and cAMP-dependent signal transduction pathways might exist in human cavernous and cardiac muscle that may be of pharmacologic significance.

Colforsin↗
PubMed2000

Ten years experience with lung and heart-lung transplantation in primary and secondary pulmonary hypertension.

OBJECTIVE: Patients with primary pulmonary hypertension (PPHT) have a worse natural outcome compared with those with secondary pulmonary hypertension in Eisenmenger's syndrome (ES) and chronic pulmonary embolism (CPE). Lung transplantation (SLTx, DLTx, HLTx) still remains the only therapeutical option for patients with this type of endstage lung disease. METHODS: From 1988 to 1998, 63 patients underwent lung transplantation for PPHT (n=29, 9 m, 20 f, 2 SLTx, 14 DLTx, 13 HLTx), ES (n=29, 13 m, 16 f, 2 SLTx, 3 DLTx, 24 HLTx) or CPE (n=5, 2 m, 3 f, 1 SLTx, 2 DLTx, 2 HLTx). Groups were comparable for NYHA functional class, preoperative pulmonary arterial pressure, recipient and donor age, ischemic time, necessity and duration of cardiopulmonary bypass and cross-match. RESULTS: The 1-, 3- and 5-year survival was 52, 40 and 35% for the PPHT-group, 83, 78 and 74% for the ES-group and 80, 60 and 60% for the CPE-group, respectively (P=0.026, P=0.033, P=0.082 for 1-, 3- and 5-year survival). Patients following DLTx showed a lower 1-year survival rate as compared with patients after HLTx both in PPHT patients (36 vs. 62%, P=0.091) and in ES patients (67 vs. 83%, P=0.213). The incidence of bronchiolitis obliterans syndrome was 29% at 1 year and 45% at 3 years for the PPHT-group vs. 17 and 65% for the ES-group (n. s. in between groups). Excluding postoperative ventilation time (PPHT-group: 26.8+/-24.0 days vs. ES-group: 16.1+/-30.8 days, P=0. 011) and a higher incidence of infectious causes of death (PPHT-group n=8 vs. ES-group n=1, P=0.017) groups were comparable with regard to their postoperative courses. CONCLUSIONS: It is concluded, that predominantly the underlying primary disease influences graft survival after lung transplantation in patients with pulmonary hypertension compared with all other patient and procedure dependent factors. Lung transplantation in patients with PPHT requires further investigations to achieve results comparable with other indications.

Adult↗
PubMed2000

[Harvesting the vena saphena magna for aortocoronary bypass operations--is the subcutaneous suture necessary?].

BACKGROUND: The need for stitching the subcutaneous layers after saphenous vein graft harvest for coronary artery bypass is discussed controversially. METHODS: We conducted a prospective study to determine whether subcutaneous stitches reduce the incidence of hematoma, infection and wound dehiscence after saphenous vein graft harvest in patients undergoing coronary artery bypass grafting. Patients were randomized either to group 1 (n = 100, subcutaneous suture) or group 2 (n = 46, without subcutaneous suture). Leg wounds were examined for hematoma, wound dehiscence, necrosis or secretion preoperatively and on day 2 and 5 after surgery. Furthermore, leg circumferences were measured at distinct areas. RESULTS: There were no significant differences in the incidence of wound complications. Especially, leg circumferences and incidence of hematomas (group 1: 36% versus group 2: 39%) as well as the length of hospital stay (group 1: 6.8 days versus group 2: 6.2 days) did not differ significantly. CONCLUSIONS: The subcutaneous suture following saphenectomy is unnecessary. A deterimental effect of an additional subcutaneous suture could not be demonstrated.

Aged↗
PubMed2000

Immunochemical evidence for a unique GPI-anchored carbonic anhydrase isozyme in human cardiomyocytes.

To clarify the controversial question of cell-specific distribution of carbonic anhydrase (CA) in the heart, endothelial cells and cardiomyocytes were isolated from porcine and human hearts and were characterized with cell-specific markers. CA activity was found in the microsomal fraction of both cell types. It was shown by Triton X-114 phase separation that both cell types possess a membrane-bound form of CA. These CAs share the same mechanism of membrane-anchoring via glycosylphosphatidylinositol (GPI), which excludes identity with transmembrane isoforms CA IX or CA XII. Western blotting analysis of human microsomes with anti-human CA IV antibodies revealed a marked difference in immunoreactivity. Endothelial CA activity resulted in 11-fold stronger CA IV bands compared with identical amounts of myocytic CA activity, indicating that cardiac endothelium and cardiomyocytes possess immunologically distinct forms of CA. We conclude that in human hearts CA IV is associated with the endothelium, whereas most of the CA in myocytes is not identical with one of the known CA isozymes. This suggests that cardiomyocytic CA is a novel isozyme.

Animals↗
PubMed2000

Hemoptysis following left ventricular aneurysm repair: a misleading clinical sign.

We report on a 66-year-old man with severe hemoptysis following coronary artery bypass grafting and repair of a left ventricular septal defect after acute myocardial infarction. Initial diagnosis was delayed by misleading clinical symptoms and radiologic studies. Due to subfebrile temperature and sputum culture positive for Pseudomonas aeruginosa, he had been treated with antibiotics before reoperation. At reoperation, replacement of all foreign material and reconstruction of the ventricular repair with bovine pericardium resulted in reinfection with the same organism despite prolonged antibiotic therapy after 6 months. Removal of the pericardial tissue with direct suture closure of the ventricles and interposition of omentum led to complete healing of the infection without reoccurrence after 2 years.

Aged↗
PubMed2000

[Advances and perspectives of heart-lung transplantation].

Thoracic organ transplantation has evolved as standard therapy in end-stage cardiac and pulmonary failure. Meanwhile more than 50,000 heart, 2500 heart-lung and 10,000 lung transplantations have been performed worldwide. Improvements in patient selection as well as in the postoperative management have led to 1-year survival rates of 70-90%. Long-term results are still influenced by the development of graft vessel disease, bronchiolitis obliterans syndrome and malignancies. Furthermore, indications and results of different procedures will be presented and new developments discussed.

Aged↗
PubMed1999

Ascending aortic replacement with aortic valve reimplantation.

BACKGROUND: Reimplantation of the native, structurally intact aortic valve within a Dacron tube graft in patients with aortic root aneurysms corrects annular ectasia and dilatation of the sinotubular junction. The durability of this valve repair with respect to the increased mechanical stress on valve cusps has been discussed, is quite controversial, and is yet unknown. METHODS AND RESULTS: From July 1993 to November 1998, a replacement of the ascending aorta with a repair of the aortic valve was performed in 75 patients (53 men and 22 women aged 50+/-19 years). Twenty-one patients (28%) had Marfan syndrome, and 11 patients (15%) had an aortic dissection, type Stanford A (6 acute, 5 chronic). In 17 patients (23%), concomitant replacement of the aortic arch was necessary. Clinical and echocardiographic follow-up was performed in 6- to 12-month intervals for a cumulative study period of 137 patient-years. No operative deaths occurred. Two patients (3%) died 5 and 20 months postoperatively. One additional patient experienced a transient ischemic attack within the first postoperative week. Three patients (4%) with progressive aortic insufficiency required aortic valve replacement after 9, 11, and 14 months. All other patients had no or mild aortic insufficiency. The repairs have now remained stable for </=65 months (mean, 22+/-20 months). Other valve-related complications did not occur. CONCLUSIONS: Our results demonstrate that this type of aortic valve repair achieves excellent results in selected patients. Perfect coaptation of valve cusps during the repair with no or only trace aortic insufficiency at initial echocardiography seems to be essential for durability.

Adolescent↗
PubMed1999

Surfactant replacement in reperfusion injury after clinical lung transplantation.

BACKGROUND: Reperfusion injury remains a significant risk factor in the immediate postoperative course after lung transplantation. We report on our initial clinical experience of surfactant replacement in reperfusion injury after clinical lung transplantation. METHODS AND RESULTS: In 31 consecutive patients, lung (8 single lung, 16 bilateral lung) or heart-lung (7) transplantation was performed. In 6 patients, severe reperfusion injury developed and was treated with continuously nebulized surfactant. Compliance of the allograft increased 40 +/- 25 % within 3 h following treatment with surfactant. Alveolar arterial oxygen gradient decreased by 23 +/- 11 % after 3 h and by 35 +/- 20 % after 6 h. Normal graft function was reestablished within 1-3 days after transplantation. All treated recipients were extubated until the 6th postoperative day. The 30-day mortality for the 31 recipients was 3.3 %, the 1-year survival 84 %. CONCLUSIONS: Surfactant replacement may become a clinical method for treatment of reperfusion injury after lung transplantation.

Adult↗
PubMed1999

C1-esterase inhibitor in graft failure after lung transplantation.

Graft failure after lung transplantation may occur immediately after transplantation due to reperfusion injury or later due to rejection and infection. Although the pathological mechanisms are not completely known, the clinical findings are similar to the adult respiratory distress syndrome. In this condition, the blood coagulation contact system and the complement system are activated, leading to a capillary leak syndrome. Activation of the contact as well as the complement system is regulated by a common inhibitor, C1-esterase inhibitor (C1-INH). We report on two patients who received high doses of C1-INH for 2 days during graft failure either due to reperfusion injury immediately after transplantation or due to an acute rejection 2 months after double-lung transplantation. In both cases of graft failure, a capillary leak syndrome occurred with pleural effusions of 7 l to more than 10 l per day. In case 1 disturbance of gas exchange during severe reperfusion injury could not be treated effectively with other treatment modalities like nitric oxide ventilation or surfactant administration. With the use of C1-INH, pleural effusions reduced within 12 h, leading to normal graft function within 4 days. In the second recipient, acute rejection forced the use of extracorporeal membrane oxygenation (ECMO) within 24 h despite immunosuppressive therapy. After administration of C1-INH, pleural effusions reduced from 19 l per day to 300 ml within 3 days of treatment. ECMO was discontinued after C1-INH treatment and the patient extubated 2 weeks later. This experience indicates that C1-INH may play a role in the management of capillary leak syndrome after lung transplantation.

Capillary Leak Syndrome↗
PubMed1999

[Coronary vasculopathy after heart transplantation--effect of temporal onset, severity and progression on long-term prognosis].

Despite considerable progress in the knowledge about pathophysiology of cardiac allograft vascular disease (CAVD), only few systematic studies are available, characterizing the natural course during long-term follow-up after heart transplantation (HTX). Therefore, we analyzed in 354 heart transplant recipients (305 male, 45.9 +/- 11.2 years, mean observation period 5.8 +/- 3.0 years, range 0.9-12.4 years) the results of 1129 coronary angiograms under the aspects of development, severity, localization, and progression of disease related to the prognosis of patients. As expected an increasing prevalence was found over time with a luminal obstruction > or = 30% in 83% of all patients more than 10 years after HTX. Coronary artery stenosis (> or = 50%) at initial diagnosis was predominantly localized in the LAD (46%) followed by RCX (31%) and RCA (23%). Angiographic risk profiles with an impaired prognosis could be identified in the form of an early development (< 4 years post HTX) of disease (p = 0.03), luminal obstruction > 50% (p = 0.001), and multivessel appearance at first diagnosis (p = 0.02) as well as in progressive forms of CAVD (p = 0.001). Summarizing, CAVD is a frequent finding in HTX recipients. Especially in patients with early onset, progressive, and advanced stages of disease it represents a prognostically limiting complication following HTX. Identification of the natural course is of major importance defining the need and efficacy of future palliative therapeutical approaches.

Adolescent↗
PubMed1999

Different approaches for minimally invasive closure of atrial septal defects.

BACKGROUND: To improve the acceptance of cosmetic results after closure of atrial septal defects, anterior or lateral thoracotomies are preferred rather than median sternotomies. Along with the availability of minimally invasive techniques, a further reduction in incision length appeared feasible while preserving thoracic stability. METHODS: Various minimally invasive approaches differing in the type of incision and mode of cannulation have been applied under conditions of normothermic ventricular fibrillation. In technique 1 (n = 5), a right parasternal mini-incision was combined with a central aortic and bicaval cannulation. Technique 2 (n = 2) was composed of an anterior submammary mini-incision with femoral arterial and central bicaval cannulation. To optimize the surgical access, the transincisional cannulation of the superior vena cava was replaced by a percutaneous cervical cannulation (technique 3, n = 17). RESULTS: Effective atrial septal defect closure assessed by intraoperative echocardiography was achieved in all patients. Central neurologic complications were completely absent. Besides temporary atrial fibrillation in one case, no other cardiac complications occurred. There were no cases with complicated wound healing. CONCLUSIONS: Along with modified cannulation techniques and intraoperative echocardiography, minimally invasive techniques can be safely applied for atrial septal defect closure. Submammary incisions were highly accepted and allowed for adequate surgical exposure.

Adolescent↗
PubMed1999

Aortic valve replacement: is the stentless xenograft an alternative to the homograft? Midterm results.

BACKGROUND: This study was performed to assess the midterm clinical results after aortic valve replacement (AVR) with stentless xenograft (SX) compared with cryopreserved aortic or pulmonary homografts (HX). METHODS: In 139 patients (<60 years) undergoing elective AVR, 59 HX and 80 SX were inserted. All patients were followed clinically and by color flow Doppler echocardiography for 45+/-12 months (range 31-58 months). RESULTS: There were 5 in-hospital deaths (3.5%): 4 HX and 1 SX (p = NS). The mean gradient was 6+/-2 mm Hg in HX versus 13+/-6 mm Hg in SX (p<0.001) and remained unchanged during follow-up. Actuarial survival (HX 77%, SX 80%), freedom from endocarditis (HX 91%, SX 99%), freedom from thromboembolic events (HX 98%, SX 90%), and freedom from reoperation (HX 98%, SX 100%) were comparable between groups after 58 months. CONCLUSIONS: Despite slightly higher transvalvular gradients, the stentless aortic valve achieved excellent midterm results, when compared with homografts.

Actuarial Analysis↗
PubMed1999

The use of gelatin-resorcin-formalin glue in acute aortic dissection type A.

OBJECTIVES: The Gelatin-resorcin-formalin (GRF) glue is widely used in the surgical treatment of dissecting aneurysms. This paper is focused on our experience with the GRF glue in cases, operated for acute aortic dissection type A. METHODS: Between September 1990 and December 1997, 164 patients were operated on for acute aortic dissection type A. In 148 patients GRF was used to reinforce the dissected layers proximal (n = 106) or distal (n = 144) of the grafted aortic segment. An intervention at the aortic valve was necessary in 93 instances. In 111 patients, an open distal anastomosis for replacement of the proximal aortic arch was performed. Thirty-seven additional patients underwent subtotal or total aortic arch replacement. RESULTS: Early postoperative mortality was 26.2% (43/164 patients). Another 16 patients died late postoperatively. Actuarial survival rates are 69.9% at 1 year, 62.5% at 3 years, 59.4% at 5 years and 56.1% at 7 years, post-operatively. Twenty-two reoperations were performed in 20 patients (16.5%). Nine of these patients had developed complications in aortic segments that underwent reconstruction by use of GRF during the primary intervention. Aortic root redissection was found in 7/9 patients intraoperatively, whereas 1/9 patients presented with a rupture near the distal graft to aortic anastomosis. CONCLUSIONS: The introduction of GRF glue has greatly facilitated the reconstruction of dissected aortic wall layers adjacent to the vascular graft. However, the use of the adhesive for aortic root reconstruction in acute aortic dissection type A may bear a significant risk of late postoperative proximal aortic redissection. Complications associated with the GRF glue are likely to be due to the toxic effects of the formalin component. Therefore, care should be taken that the amount of formalin administered to the glue components remains as low as possible.

Acute Disease↗
PubMed1999

Replacement of ascending aorta with aortic valve reimplantation: midterm results.

OBJECTIVE: Aneurysms of the aortic root lead to aortic valve incompetence due to dilatation of the sinotubular junction and annuloaortic ectasia. Reimplantation of the native, structurally intact aortic valve within a Dacron tube graft corrects annular ectasia as well as dilatation of sinotubular junction and aortic sinuses. Durability of this valve repair with respect to increased mechanical stress on valve cusps is discussed controversially and is yet unknown. METHODS: Since 7/93, replacement of the ascending aorta with repair of the aortic valve was performed in 48 patients (34 male, 14 female; 47+/-20 years) with aortic insufficiency and aneurysm of the aortic root. Fifteen patients (31%) had Marfan's syndrome and five patients (10%) had an aortic dissection type A (two acute, three chronic). In 11 patients (23%), concomitant replacement of the aortic arch was necessary utilizing elephant trunk technique in two patients. Additionally, one patient required mitral valve repair and two other patients coronary artery bypass grafts. Clinical and echocardiographic follow-up was performed in 6-12 month intervals for a cumulative study period of 100 patient years. RESULTS: There were no operative deaths. Two patients (4%) died 5 and 20 months postoperatively. One additional patient experienced a TIA within the first postoperative week. Three patients (6%) with an early postoperative aortic insufficiency (AI) > 1 required aortic valve replacement after 9, 11, and 14 months due to progressive AI. In these patients, distortion of the aortic root geometry led to valve incompetence. All other patients have no or mild aortic insufficiency. The repair now remains stable for up to 63 months (mean 25+/-18 months). Other valve related complications did not occur. CONCLUSIONS: Our results demonstrate that this type of aortic valve repair achieves excellent results in selected patients. Perfect coaptation of valve cusps during the repair with no or only trace AI at initial echocardiography seems to be essential for durability.

Adolescent↗