Biomedical subjects

J F Matthias Bechtel

Publications and source records attributed to J F Matthias Bechtel.

8 recordsLinked to original sources

PubMed2003

Local generation of C-reactive protein in diseased coronary artery venous bypass grafts and normal vascular tissue.

BACKGROUND: Venous coronary artery bypass grafts (CABGs) are prone to accelerated atherosclerosis. In atherosclerotic diseases, serum C-reactive protein (CRP) levels have become an important diagnostic and prognostic marker. The origin of CRP in this setting remains to be elucidated. METHODS AND RESULTS: Monoclonal anti-CRP identified CRP expression in medial and intimal alpha-actin-positive smooth muscle cells (SMCs) of diseased CABGs with type V and VI lesions and also of native saphenous veins of atherosclerotic individuals. In addition, patent coronary arteries with type IV and V but not with type I through III lesions exhibited intense SMC staining for CRP. Calcified desobliterates of occluded coronary arteries with end-stage disease did not show SMC staining for CRP and were consistently negative for CRP mRNA, as detected by means of real-time polymerase chain reaction. However, CRP mRNA was expressed in 11 of 15 diseased CABGs and also in 10 of 15 native veins. By contrast, only 3 of 18 internal mammary and 4 of 12 radial arteries with virtually no atherosclerosis were positive for CRP mRNA. CONCLUSIONS: CRP is produced by SMCs of atherosclerotic lesions with active disease but not in end-stage plaques. The role of CRP constitutively expressed by normal vascular tissue in vein graft disease has yet to be elucidated.

Arteriosclerosis↗

PubMed2003

Low-energy cardioversion versus medical treatment for the termination of atrial fibrillation after CABG.

BACKGROUND: Atrial fibrillation (AF) is the most frequent complication after cardiac surgery and can cause considerable morbidity. Low-energy cardioversion (LEC) using biatrial epicardial wires implanted during surgery has been shown to be effective and safe in conscious patients, but has not been directly compared with medical treatment so far. We therefore prospectively studied the efficacy of LEC in men 60 years of age and older. METHODS: Sixteen patients (mean +/- SD, 66.4 +/- 5.4 years) were randomized to LEC and 32 patients (66.3 +/- 5.0 years) to standarized medical treatment in the event of postoperative AF. Age, comorbidity, and surgical variables did not differ significantly between the groups. RESULTS: After cardiac surgery, AF occurred in 6 patients (38%) assigned to LEC and in 11 patients assigned to medical treatment (34%; p = NS). Low-energy cardioversion restored sinus rhythm in all but 1 patient, and 1 patient in the LEC group had early recurrence of AF. All other patients in the LEC group had prompt and stable restoration of sinus rhythm. Medical treatment was associated with the restoration of sinus rhythm in all patients. Although the total time in AF was decreased significantly by LEC (median 5 minutes versus 22 hours; p = 0.037), the length of postoperative hospitalization was not (5.1 +/- 1.4 days for the LEC group compared with 5.3 +/- 1.6 days for controls). CONCLUSIONS: Low-energy cardioversion significantly decreased the amount of time cardiac surgery patients spent in AF after the operation. Larger studies are needed to determine whether this new treatment modality has the ability to decrease morbidity associated with postoperative AF and is cost-effective.

Aged↗

PubMed2003

Up to 7 years' experience with valve-sparing aortic root remodeling/reimplantation for acute type A dissection.

BACKGROUND: Aortic valve-sparing operations for acute type A dissection are appealing and innovative but less well defined surgical techniques requiring further evaluation. METHODS: We reviewed all consecutive patients with acute type A dissection who underwent either the remodeling (group 1, n = 21) or the reimplantation valve-sparing technique (group 2, n = 15) since October 1994. Patients were followed up clinically and echocardiographically for as long as 41.3 months (group 1) and 87 months (group 2). RESULTS: Hospital mortality was 19% (n = 4) for group 1 and 20% (n = 3) for group 2. Permanent new neurologic symptomatology occurred in 1 patient (3.6%). Three patients in group 1 required reoperation owing to redissection. No patient had an aortic insufficiency of more than grade 1. No late neurologic or thrombembolic events occurred. There was no statistically significant difference between both groups with respect to clinical and hemodynamic data. CONCLUSIONS: Remodeling and reimplantation aortic valve-preserving operations in acute type A dissection can be performed with adequate perioperative risk and excellent midterm aortic valve function. We found no evidence of one technique being superior to the other, however durability of the remodeling technique needs critical consideration especially in Marfan syndrome and when glue is used.

Acute Disease↗

PubMed2003

A rise of MMP-2 and MMP-9 in bronchoalveolar lavage fluid is associated with acute lung injury after cardiopulmonary bypass in a swine model.

Postoperative acute lung injury (ALI) contributes to the morbidity and mortality following cardiopulmonary bypass (CPB). To determine whether the presence of matrix metalloproteinases (MMPs) is associated with ALI after CPB, MMP-2 and MMP-9 activities in bronchoalveolar lavage fluid (BALF) were compared with parameters indicating impaired gas exchange. In a prospective study, 17 minipigs were subjected to CPB for 60 min. Before and at five and 180 min after CPB, MMP-2 and MMP-9 were assayed in BALF and the arterial-alveolar gradient of oxygen tension (AaDO2), the pulmonary capillary wedge pressure (PCWP) and the water content of lung tissue samples (Wt) were evaluated and compared with baseline values. MMP-2 and MMP-9 increased significantly 5 minutes (2.1- and 6.2-fold, respectively) and 180 minutes (3.4- and 14.3-fold, respectively) post-CPB. AaDO2 and Wt, but not PCWP, increased significantly 180 minutes after CPB and only AaDO2, but not PCWP or Wt, was significantly correlated with MMP-2 (r = 0.66, p = 0.006) and MMP-9 (r = 0.62, p = 0.01). In conclusion, high levels of MMP-2 and MMP-9 in the pulmonary compartment are associated with ALI after CPB.

Animals↗

PubMed2003

Histopathological grading of ascending aortic aneurysm: comparison of patients with bicuspid versus tricuspid aortic valve.

BACKGROUND AND AIMS OF THE STUDY: Bicuspid aortic valve (BAV) is a common inherited condition that is often accompanied by ascending aortic aneurysm. A high level of histological wall abnormalities was reported to be present in non-dilated aortas of patients with BAV. In patients with tricuspid aortic valve, there appears to exist a direct relationship between the diameter of the ascending aorta and degree of histopathological aortic wall abnormalities. Whether this situation exists in patients with BAV has not yet been investigated. METHODS: Surgical and medical records of all patients undergoing surgery of the ascending aorta were reviewed. A total of 65 patients was identified in whom an aortic wall specimen was obtained intraoperatively. These specimens were systematically re-evaluated, and graded according to the severity of seven histopathological conditions: fibrosis, atherosclerosis, medionecrosis, cystic medial necrosis, smooth muscle cell orientation, elastic fiber fragmentation, and inflammation. RESULTS: BAVs were present in 26 patients (40%). Patients with BAV had significantly less aortic wall alterations than patients with tricuspid aortic valves (p < 0.001) in all variables examined. The severity of aortic wall abnormalities was significantly dependent on aortic diameter in patients with BAV as well as tricuspid aortic valve (p = 0.036 and 0.019), but dependent on age (p = 0.009) only in patients with tricuspid aortic valve. CONCLUSION: The study results provide evidence that ascending aortic aneurysm in patients with BAV differs clinically and histologically from that in patients with tricuspid aortic valve. Further studies are needed to elucidate the impact of inherited and acquired aortic wall abnormalities on the development of aneurysms.

Adult↗

PubMed2002

Is the kaolin or celite activated clotting time affected by tranexamic acid?

BACKGROUND: During cardiopulmonary bypass, the activated clotting time is frequently used for determination of anticoagulation, and either Celite or kaolin are used as activators. If aprotinin is administered concomitantly, the Celite activated clotting time (C-ACT) becomes significantly higher than the kaolin activated clotting time (K-ACT). Therefore, insufficient anticoagulation using C-ACT in the presence of aprotinin is a major concern. Whether the application of tranexamic acid (TA), a pharmacologic alternative to aprotinin, has similar effects has not been studied before. METHODS: An in vitro study using the blood of healthy volunteers was performed. Both C-ACT and K-ACT were measured at baseline, after adding TA, and after adding TA and heparin. In addition, 30 patients undergoing primary cardiac operations had simultaneous measurements of C-ACT and K-ACT after skin-incision, 5 minutes after the application of heparin and TA, every 30 minutes during cardiopulmonary bypass, and 10 minutes after the application of protamine. RESULTS: In vitro, C-ACT and K-ACT correlated significantly at each measurement. Tranexamic acid had no influence on the activated clotting time. In vivo, C-ACT and K-ACT did not differ significantly, but at each time C-ACT tended to be greater than K-ACT (p = 0.086). The average difference between K-ACT and C-ACT was stable before and after the application of TA (p = 0.85) but the variability of the differences significantly increased during cardiopulmonary bypass (p < 0.001). CONCLUSIONS: Application of TA does not seem to differentially affect the mean C-ACT and K-ACT. No recommendation seems warranted to prefer one activator over the other in patients receiving TA.

Aged↗

PubMed2002

Lung protection during total cardiopulmonary bypass by isolated lung perfusion: preliminary results of a novel perfusion strategy.

BACKGROUND: The present pilot study was conducted to evaluate the effect of isolated short-term lung perfusion during cardiopulmonary bypass (CPB) on inflammatory response and oxygenation. METHODS: A total of 24 patients undergoing elective cardiac surgery with routine CPB were prospectively assigned to three groups. Group I (n = 7), control subjects receiving neither lung perfusion nor ultrafiltration; group II (n = 9), patients undergoing lung perfusion; and group III (n = 8), patients undergoing lung perfusion plus ultrafiltration. Lung perfusion consisted of single-shot hypothermic pulmonary artery perfusion with oxygenated blood. Proteins indicative of leukocyte activation and lung injury were measured in plasma and bronchoalveolar lavage fluid (BALF). The alveolar-arterial oxygen gradient (A-aDO2) and the oxygenation index (PO2/FiO2) were also determined. RESULTS: Oxygenation values were best preserved in group III, followed by group II. After CPB, elastase-alpha1-proteinase inhibitor complex had increased in plasma in all groups; in BALF it increased in groups I and II, but not in group III. Alpha2-macroglobulin increased significantly in BALF in group I but not in groups II and III. CONCLUSIONS: These preliminary results provide some evidence that single-shot hypothermic lung perfusion with oxygenated blood at the beginning of CPB may have a protective effect on the lungs, especially when combined with ultrafiltration.

Adult↗

PubMed1998

Discrepancies between sizer and valve dimensions: implications for small aortic root.

BACKGROUND: Precise labeling of sizer and valve diameters is crucial for optimal valve selection especially in the small aortic root. This study examines the accuracy of manufacturers' markings on small aortic prostheses and sizers. METHODS: Sizer and valve dimensions of 22 different mechanical aortic prostheses (19 to 23 mm) were evaluated by caliper micrometer measurements. RESULTS: Nearly all sizers exceeded their marked dimensions by up to 1.0 mm. Measured tissue annulus diameters for 19-mm-labeled valves varied between 18.3 and 19.6 mm, for 21-mm valves from 20.5 to 21.6 mm, and for 23-mm valves from 22.4 to 23.5 mm, respectively. The orifice areas ranged from 1.5 to 2.06 cm2 for 19-mm valves, from 2.0 to 2.55 cm2 for 21-mm valves, and from 2.4 to 3.09 cm2 for 23-mm valves, respectively. CONCLUSIONS: Actual sizer dimensions and tissue annulus diameters of various small mechanical aortic prostheses varied considerably from their marked diameters. These differences should be considered to ensure the optimal prosthesis selection for each patient.

Aortic Valve↗