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Biomedical subjects

Thomas Schachner

Publications and source records attributed to Thomas Schachner.

32 records · Page 2Linked to original sources
PubMed2005

Hybrid coronary artery revascularization: logistics and program development.

Planning hybrid coronary artery revascularization--a combination of cardiac surgery with percutaneous procedures--requires, at first sight, a very complex logistical setup. Technical and equipment related details should be defined as early as possible in order to have time for training of all OR personnel involved. The most challenging aspect in OR-located hybrid coronary revascularization remains a very close cooperation of cardiac surgeons and interventional cardiologists. This teamwork does include indication findings and subsequent referral of multivessel coronary artery disease patients to hybrid procedures, as well as high individual flexibility of interventionalists and surgeons. The major prerequisite for this cooperation is a mutual acceptance of different revascularization approaches and the intent to combine their most striking advantages. Intraoperative graft angiography during coronary artery bypass grafting (CABG) procedures is one important step toward simultaneous hybrid coronary revascularization procedures. We describe our experience with on table angiography using a mobile C-arm for intraoperative imaging. This fluoroscopy system can in selected cases be used for simultaneous hybrid procedures.

Adult↗
PubMed2005

Does preoperative multislice computed tomography predict operative times in total endoscopic coronary artery bypass grafting?

OBJECTIVE: Multislice computed tomography (MSCT) is currently discussed as a potential tool for procedure planning in endoscopic heart surgery. We aimed to assess the influence of various thoracic measurements on operative times in arrested heart totally endoscopic coronary artery bypass grafting (AHTECAB). METHODS: 34 patients (aged 59 years, 71% male) scheduled for AHTECAB were examined prospectively with ECG-gated 16-channel MSCT angiography of coronary arteries and internal mammary arteries. All AHTECABs were single LIMA to LAD bypass operations using the Da Vinci telemanipulator and the ESTECH remote access perfusion system. RESULTS: The LIMA-LAD distances were: I (at origin of the first diagonal branch) 4.3 cm (2.5-6.0), II (aortic valve level) 3.7 cm (1.1-6.4), III (mitral valve level) 2.9 cm (0.7-5.0), and IV (basis cordis) 2.3 cm (0.6-4.3). The anterioposterior thoracic diameter was 12.4 cm (8.9-15.6), and the transverse diameter was 24.9 cm (21.1-26.8). LIMA-LAD distances I (P = .025, r = .396) and III (P = .042, r = .356) significantly correlated with the anastomotic time. Increased rotation of the heart to the left was associated with a decreased cardiopulmonary bypass time (p = .016, r = -.451). CONCLUSION: These data suggest that MSCT has the potential to predict operative times in robotic AHTECAB.

Coronary Angiography↗
PubMed2005

Assessment of health-related quality of life after coronary revascularization.

The use of patient-oriented outcomes, in particular health-related quality if life (HRQOL), to evaluate coronary revascularization is continuously increasing. Current data underline that patients undergoing conventional CABG show a tremendous improvement of HRQOL status as early as 3 months postoperatively. There seems to be no clear benefit concerning HRQOL for off-pump coronary surgery versus conventional CABG. The benefits of minimal invasive CABG via mini-thoracotomy are compromised by increased incidence of pain during the immediate postoperative period. Totally endoscopic approaches seem to be more effective with regard to pain reduction and resume of every day activities. Compared to catheter-based interventions there is evidence that conventional CABG offers significant advantages over PCI. The influence of drug-eluting stents and newer surgical techniques on HRQOL remains to be determined. Inclusion of HRQOL data in CABG and PCI databases can play a central role in order to identify patient groups who benefit the most from each revascularization strategy.

Angioplasty, Balloon, Coronary↗
PubMed2005

High-resolution 16-MDCT evaluation of radial artery for potential use as coronary artery bypass graft: a feasibility study.

OBJECTIVE: The objective of our study was to assess the feasibility of using 16-MDCT angiography for the preoperative assessment of the radial and ulnar arteries and the palmar arches in patients scheduled for radial artery harvesting for coronary artery bypass graft (CABG) surgery. CONCLUSION: Sixteen-MDCT angiography shows promise for the noninvasive preoperative assessment of the radial artery as a CABG donor site.

Aged↗
PubMed2004

Neointimal Hyperplasia in Coronary Vein Grafts: Pathophysiology and Prevention of a Significant Clinical Problem.

Abstract Neointimal hyperplasia in aortocoronary vein grafts represents a significant problem that, by itself or by development of vein graft atherosclerosis, leads to the return of symptoms and to major adverse cardiac events after coronary artery bypass grafting. The main causes of neointimal hyperplasia are surgical trauma, intraoperative ischemia reperfusion injury, and implantation of a vein into the arterial circulation. All these pathogenetic factors cause a loss of protective endothelial mediators. The initiating steps lead to the induction of a significant inflammatory response and to the production of mitogenic factors in the vascular wall. DNA synthesis in vascular smooth muscle cells is markedly up-regulated, and intracellular signal transduction leads to transcription of immediate early genes, which causes an intense proliferative response. Vascular smooth muscle cells proliferate, migrate through the internal elastic lamina with the support of proteases, and transform from contractile-type into secretory-type cells. A thick layer of neointima is formed. The prevention of neointimal hyperplasia includes meticulous surgical technique, the choice of a large target vessel, and adequate intraoperative storage of the vein graft. Local intraoperative therapy of the implanted graft has been successfully tested in the experimental setting with a variety of substances that tackle different steps in the pathologic mechanism. Systemic pharmacologic therapy in clinical use primarily consists of the use of platelet inhibitors and anticoagulants. The transfer of experimental knowledge to bedside application has been slow. Gene therapy represents a promising field for the improved management of vein graft neointimal hyperplasia.

Journal Article↗
PubMed2004

Effects of intracoronary shunts on coronary endothelial coating in the human beating heart.

BACKGROUND: Local occlusion of coronary arteries during beating heart revascularization leads to injury of the arterial wall especially disturbing the integrity of the endothelium. The aim of this study was to elucidate the effects of intracoronary shunts versus local occlusion with elastic silicone loops on the beating heart in human coronary arteries by scanning electron microscopy. METHODS: Coronary arteries of patients with dilated cardiomyopathy (n = 4) or ischemic heart disease (n = 8) undergoing heart transplantation were locally occluded either with a silicone loop or with a shunt inserted after arteriotomy. Unmanipulated segments of the coronary arteries served as controls. Integrity of the endothelial lining was observed with scanning electron microscopy. RESULTS: Scanning electron microscopy revealed a statistically significant higher injury after shunting compared with controls (p < 0.001) and vessel loop occlusion (p < 0.001). There was no difference between both patient groups according to control specimens or after manipulation. CONCLUSIONS: From this investigation we conclude that insertion of intracoronary shunts during beating heart surgery leads to severe endothelial denudation in human coronary arteries. Therefore, at present we recommend using intracoronary shunts selectively in cases in which critical ischemia or technical difficulties as a result of anatomic conditions are expected during anastomosis and avoiding routine shunt insertion into coronary arteries during beating heart revascularization.

Coronary Vessels↗
PubMed2004

Local application of rapamycin inhibits neointimal hyperplasia in experimental vein grafts.

BACKGROUND: Rapamycin is an immunosuppressive agent which also exhibits marked antiproliferative properties. Rapamycin coated stents have been demonstrated to suppress restenosis in experimental and clinical studies of percutaneous coronary catheter intervention. We investigated whether rapamycin can reduce neointima formation in a mouse model of vein graft disease. METHODS: C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a previously described cuff technique. In the treatment group, 100 microg or 200 microg of rapamycin was applied locally in pluronic gel. The control group did not receive local treatment. Grafts were harvested at 1, 2, 4, and 6 weeks and underwent morphometric analysis as well as immunohistochemical analysis. RESULTS: In grafted veins without treatment (controls), median intimal thickness was 9.6 (6.4 to 29)microm, 11.9 (7.9 to 39.9)microm, 46.6 (12.4 to 57.7)microm, and 57.5 (32.5 to 71.1)microm after 1, 2, 4, and 6 weeks, respectively. Treatment with 100 microg or 200 microg rapamycin showed a dose dependent reduction of intimal thickness. In the 200 microg rapamycin treatment group the intimal thickness was 4.3 (3.4 to 5.6)microm, 3.8 (3.2 to 6.3)microm, 17.1 (4.8 to 63)microm, and 33.9 (11.3 to 80.3)microm after 1, 2, 4, and 6 weeks, respectively. This difference of intimal thickness of 200 microg treated animals compared with controls was statistically significant at 1 and 2 weeks. Immunohistochemically the reduction of intimal thickness was associated with a decreased amount of infiltration of CD-8 positive cells and a decreased amount of metallothionein positive cells in the rapamycin treated grafts. CONCLUSIONS: We conclude that perivascular application of rapamycin inhibits neointimal hyperplasia of vein grafts in a mouse model. These results suggest that rapamycin may have a therapeutic potential for the treatment of vein graft disease.

Animals↗
PubMed2004

Factors associated with presence of ascending aortic atherosclerosis in CABG patients.

BACKGROUND: The indication for epiaortic scanning during coronary artery operation is still a matter of debate. Whether this test should be carried out selectively or on a routine basis is unclear. The aim of this study was to determine factors that predict the presence of atherosclerotic ascending aortic wall thickening in patients undergoing coronary artery bypass grafting (CABG). METHODS: A total of 500 CABG patients underwent epiaortic scanning using a high-frequency linear ultrasonic probe. Maximum ascending aortic wall thickness was measured and correlated with patient-related variables. RESULTS: Maximum ascending aortic wall thickness significantly correlated with age (p < 0.001), preoperative creatinine level (p = 0.004), European system for cardiac operative risk evaluation (EuroSCORE, p < 0.001), and maximum descending aortic wall thickness (p < 0.001). Body mass index and left ventricular ejection fraction showed no correlation with maximum ascending aortic wall thickness. Of the categorical variables, hypertension (p = 0.02), unstable angina (p = 0.04), chronic obstructive pulmonary disease (p = 0.02), cerebrovascular disease (p < 0.001), and peripheral vascular disease (p < 0.001) were associated with increased ascending aortic wall thickness whereas sex, diabetes, acute cases, and previous cardiac operation were not. Multivariate analysis revealed maximum descending aortic wall thickness (p < 0.001), cerebrovascular disease (p = 0.03), and peripheral vascular disease (p = 0.04) as independent variables significantly associated with maximum ascending aortic wall thickness. CONCLUSIONS: If epiaortic scanning is not carried out routinely for detection of ascending aortic arteriosclerosis it should at least be performed in patients with old age, hypertension, unstable angina, chronic obstructive pulmonary disease, cerebrovascular disease, peripheral vascular disease, elevated creatinine levels, higher EuroSCOREs, and increased wall thickness of the descending aorta.

Aged↗
PubMed2004

Perivascular application of C-type natriuretic peptide attenuates neointimal hyperplasia in experimental vein grafts.

OBJECTIVE: C-type natriuretic peptide (CNP), which is produced by vascular endothelial cells, exhibits anti-proliferative and anti-inflammatory effects. Cytotoxic T-lymphocytes may be involved in vein graft disease. Attenuation of vein graft disease necessitates a remodelling of the arterialized vein towards a more contractile phenotype which is characterized, among other factors, by the calponin amount. We investigated the effects of perivascularly applied CNP in a mouse model of vein graft disease. METHODS: C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a previously described cuff technique. In the treatment group, 10(-6)mol/l of CNP were applied locally in pluronic gel. The control group did not receive local treatment. Grafts were harvested at 1, 2, 4, and 8 weeks and underwent morphometric analysis as well as immunohistochemical analysis. RESULTS: In grafted veins without treatment (controls) median intimal thickness was 10 (6-29), 12 (8-40)microm, was 47 (12-58), and 79 (62-146)microm after 1, 2, 4 and 8 weeks, respectively. In the treatment groups, which received 10(-6)mol/l of CNP, the intimal thickness was 5 (3-6), 6 (4-15), 32 (5-54), and 43 (39-70)microm after 1, 2, 4 and 8 weeks, respectively. This reduction of intimal thickness was significant at 1, 2 and 8 weeks. Immunohistochemically, the reduction of intimal thickness was associated with a decreased infiltration of CD-8 positive cells and an increased amount of calponin in the CNP-treated grafts. CONCLUSION: We conclude that perivascular application of CNP inhibits neointimal hyperplasia of vein grafts in a mouse model. These results suggest that CNP may have a therapeutic potential for the prevention of vein graft disease.

Administration, Topical↗
PubMed2004

Experience on the way to totally endoscopic atrial septal defect repair.

BACKGROUND: Remote-access perfusion and robotics have enabled totally endoscopic closure of atrial septal defect (ASD) and patent foramen ovale (PFO). We report on a stepwise approach to a totally endoscopic procedure. METHODS: Seventeen patients (median age, 39 years; range, 21-55 years) underwent limited-access ASD or PFO closure. As a preparative step, the operation was carried out through minithoracotomy in 11 patients. In parallel, experience with robotic surgery was gained with totally endoscopic coronary artery bypass grafting procedures. After performance of ASD closures in dry-laboratory models using the da Vinci telemanipulation system, 6 patients were operated on in a totally endoscopic fashion. RESULTS: With the endoscopic approach, significant learning curves were noted for cardiopulmonary bypass time y(min) = 226 - 41 * ln(x) (P = .03) and aortic cross-clamp time y(min) = 134 - 42 * ln(x) (P = .01) (x = number of procedures). There was no hospital mortality, and no residual shunts were detected at postoperative echocardiography. Median ventilation time was 9 hours (range, 0-18 hours) for the minithoracotomy group and 6 hours (range, 4-19 hours) for the totally endoscopic group. Median intensive care unit stay was 20 hours (range, 18-24 hours) and 18 hours (range, 18- 120 hours), respectively. CONCLUSIONS: The implementation of robotic totally endoscopic closure of ASD or PFO in a heart surgery program seems to be safe. An intermediate step of performing the operations through minithoracotomy, adapting to remote access perfusion systems, and gaining experience in other robotic cardiac surgical procedures seems worthwhile. Learning curves are apparent, and adequate defect closure does not seem to be compromised by the totally endoscopic approach.

Adult↗
PubMed2004

The ESTECH remote access perfusion cannula in minimally invasive cardiac surgery.

INTRODUCTION: Peripheral access cardiopulmonary bypass (CPB) and endoclamping of the aorta are prerequisites for performance of minimal access or totally endoscopic cardiac surgery on the arrested heart. We present our experience with the ESTECH remote access perfusion (RAP) cannula in arrested-heart totally endoscopic coronary bypass grafting (AHTECAB) and atrial-septal defect (ASD) repair via minithoracotomy and totally endoscopic ASD repair. PATIENTS AND METHODS: Remote access CPB was performed in 30 patients (17 male), with a median age of 56 years (range, 21-70 years) using the ESTECH RAP cannula. Preoperatively all patients received a thoracic and abdominal CT scan. Operations were 20 AHTECAB, 5 ASD repair via minithoracotomy, and 5 robotically assisted totally endoscopic ASD repairs. Intraoperatively the patients were monitored by transesophageal echocardiography and bilateral radial artery pressure lines for correct placement of the balloon in the ascending aorta. RESULTS: Neither vascular perforation nor dissection of the aorta occurred during these surgeries. Full CPB was achieved in all patients. Because of location in a supraaortic branch fluoroscopic visualization of the guide wire was necessary in 2 of 30 cases. Once the aortic occlusion balloon was placed, repositioning was required in none of our cases. In one AHTECAB case rupture of the balloon occurred before starting the anastomosis. The cannula was replaced and the AHTECAB could be finished without complications. In one patient inguinal wound infection occurred, which was successfully revised surgically. No perioperative myocardial ischemia, stroke, or critical leg ischemia occurred, and no hospital death occurred. CONCLUSIONS: CPB and cardiac arrest can adequately be performed via a femoral access in minimally invasive cardiac surgery using the ESTECH RAP system. Intense preoperative patient evaluation and intraoperative monitoring are absolute prerequisites for safe application of the technique.

Adult↗
PubMed2003

Intraoperative angiography for quality control in MIDCAB and OPCAB.

We present our initial experience with intraoperative angiographic evaluation of coronary artery bypass grafts placed on the beating heart. Thirty-three grafts were investigated in 23 patients. Transfemoral angiography was performed using an OEC 9800 mobile C-arm. Spasm of the graft and/or target vessel was present in 11 grafts, two grafts were severely stenosed requiring surgical revision. In a third case an additional bypass graft was placed due to angiography findings. There was no hospital mortality and no significant perioperative myocardial ischemic event. All patients were free of angina 6 months postoperatively. Intraoperative angiography seems to reveal valuable information in beating heart coronary surgery.

Adult↗
PubMed2002

Axillary artery cannulation in surgery of the ascending aorta and the aortic arch.

Potential advantages of axillary artery perfusion instead of femoral perfusion are antegrade aortic flow with decreased risk of atheremboli, low risk of false lumen perfusion in aortic dissections, avoidance of groin manipulation, and a possibility of antegrade cerebral perfusion during cardiocirculatory arrest. In 20 patients undergoing proximal aortic surgery, perfusion via the axillary artery was performed with direct cannulation or with an end-to-side anastomosed Gore-Tex graft. In two patients conversion to femoral artery cannulation was necessary. There were no axillary complications, hospital mortality was three out of 22, and no stroke occurred.

Adult↗