Biomedical subjects

Sven Martens

Publications and source records attributed to Sven Martens.

17 recordsLinked to original sources

PubMed2005

Aortic leaflet replacement with the new 3F stentless aortic bioprosthesis.

PURPOSE: Clinical trials with the new 3F stentless aortic bioprosthesis began October 2001, and as one of the first centers to implant this prosthesis in humans, we would like to present our experiences with this new device. DESCRIPTION: The 3F aortic bioprosthesis is a stentless biological heart valve fabricated from three equal leaflets of equine pericardium, assembled in a tubular shape, and implanted in the native aortic root to replace the patient's diseased aortic leaflets. Between January 2002 and August 2002, 24 3F aortic bioprostheses were implanted at our institution. Effective orifice area, mean gradients, and ejection fraction were evaluated by echocardiography at discharge and at 12-month follow-ups after surgery. EVALUATION: At 12-month follow-ups, the 3F bioprosthesis showed a good hemodynamic performance with a significant drop of mean gradients to 10.3 mm Hg, a mean effective orifice area of 1.7 cm2, and a mean ejection fraction of 61.5%. CONCLUSIONS: The clinical performance of the new 3F aortic bioprosthesis is comparable with regular stentless aortic valves. However its unique design facilitates implantation.

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PubMed2005

Pericardial patch augmentation for reconstruction of incompetent bicuspid aortic valves.

PURPOSE: Reoperation rates after repair of bicuspid aortic valves are higher than for mitral valve reconstruction. Secondary changes and small coaptation surface render repair unreliable. Satisfactory results have been reported for patch augmentation for tricuspid aortic valves. We have applied this technique for the repair of bicuspid aortic valves. DESCRIPTION: Our technique retains the bicuspid morphology of the incompetent aortic valve. A strip of glutaraldehyde-fixed pericardium is sutured to the free edge of the fused leaflet. A large coaptation surface is created, and competence of the bicuspid valve is achieved. EVALUATION: Sixteen patients underwent reconstruction of their bicuspid aortic valves by pericardial patch augmentation. There were no intraoperative or postoperative deaths. The degree of aortic regurgitation was none to trivial for all patients at a mean follow-up of 3.1 +/- 3.4 months. Planimetric effective orifice areas ranged above 2 cm2. Mean aortic gradients were 8.2 +/- 4.8 mm Hg, and the mean height of coaptation surface was 14.7 +/- 2.1 mm. CONCLUSIONS: The pericardial patch augmentation technique increases coaptation surface, and thus provides reliable early competence of reconstructed bicuspid aortic valves.

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PubMed2005

Initial experience with a minimized extracorporeal bypass system: is there a clinical benefit?

BACKGROUND: Drawbacks of conventional cardiopulmonary bypass (CPB) are increased inflammatory response, deteriorated coagulation and systemic organ dysfunction. A closed extracorporeal circuit (CorX) features reduced foreign surface area and priming volume. Potential benefits were studied in comparing the CorX system with conventional CPB in arrested heart coronary artery bypass grafting (CABG). METHODS: Two hundred and four patients were randomly assigned either to CorX system (n = 101, group A) or a standard CPB with cardiotomy reservoir (n = 103, group B). Besides evaluation of perioperative data and routine blood samples, we focused on lung function and perioperative bleeding. Polymorphonuclear elastase (PMNE) and terminal complement complex (TCC) served to assess inflammatory response. RESULTS: Patient demographics and operative data did not differ between groups. Postoperative lung function was not significantly impaired comparing groups A and B. Intraoperative blood loss was significantly higher in group A compared with group B (1245 +/- 947 mL vs 313 +/- 282 mL, p < 0.0001) as well as the need of fresh frozen plasma. Postoperative chest drainage did not differ significantly between groups. Two patients in each group required re-exploration due to bleeding. One hour after CPB, PMNE as well as TCC were significantly lower in group A compared with group B (PMNE: 76 +/- 44 ng/mL vs 438 +/- 230 ng/mL, p < 0.0001; TCC: 16 +/- 8 IU/mL vs 29 +/- 19 IU/mL, p < 0.0001). CONCLUSIONS: The CorX system is safe and feasible in patients undergoing CABG. Despite of markedly reduced inflammatory reaction, no clinical benefit was observed.

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PubMed2005

Decreased intermediate term patency of automated proximal anastomoses evaluated by sequential ultrafast CT.

OBJECTIVE: The Symmetrytrade mark aortic connector creates proximal anastomoses of saphenous vein grafts using a nitinol implant. The device avoids partial clamping and thus possibly reduces neurologic complications. To evaluate graft patency, a single surgeon randomised study was performed in our institution. METHODS: Seventy-seven patients were randomised either to automated proximal anastomoses (group I, n=39, 61 vein grafts connected using the aortic connector, 47 as single, 15 as sequential bypasses) or controls (group II, n=38, 62 proximal anastomoses handsewn, 46 as single, 16 as sequential bypasses). Ultrafast CT-scans were performed on postoperative day 5 in 34 patients of group I and 16 patients of group II to evaluate early graft patency. Intermediate term patency was evaluated with ultrafast CT-scan in 30 patients of group I (46 grafts) and 25 patients of group II (39 grafts) 1 year after the operation. RESULTS: Two early graft occlusions were detected in group I (3.8%). In group II all evaluated grafts were patent 5 days after surgery. 11.4 months after surgery, seven out of 46 grafts were found occluded (15.2%) in group I. In the control group, only one occlusion was detected (2.6%). CONCLUSIONS: We observed a trend towards an increased occlusion rate 1 year after surgery with automated connector devices. For evaluation of long-term patency larger patient groups have to be evaluated. Other benefits of these devices have to be proven to promote their clinical application.

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PubMed2005

Emergency endovascular interventions for acute thoracic aortic rupture: four-year follow-up.

OBJECTIVE: High mortality and paraplegia rates associated with the surgical management of acute thoracic aortic ruptures limit its success. It was our objective to evaluate whether emergency endovascular interventions would improve the outcomes of these patients. METHODS: Sixty patients aged 28 to 83 years were admitted to our institution with an acute rupture of the thoracic aorta (27 ruptured aneurysms, 15 perforated type B dissections, 18 traumatic ruptures). Twenty-eight patients were treated surgically with cardiopulmonary bypass, and 32 patients were acutely treated with an endovascular stent graft. Medical records were reviewed for prehospital and emergency department data, operative findings, and outcomes. Patients were followed up at yearly intervals with high-resolution multidetector computed tomographic angiography. RESULTS: Perioperatively, there were 1 death (3.1%) among the 32 patients in the endovascular group and 5 deaths (17.8%) among the 28 patients in the surgical group. There were 4 late deaths in the endovascular group and 1 in the surgical group. There were 2 access failures in the endovascular group. There were 1 stroke in the endovascular group and 1 case of paraplegia in the surgical group. Three patients in the endovascular group had endovascular leaks develop that required reintervention. Two patients in the endovascular group had late thrombosis of the left subclavian artery. CONCLUSION: Despite encouraging early outcomes, midterm results suggest a trend toward increased reintervention and late complication rates in the endovascular group. Therefore continued surveillance of patients treated with stent grafts is necessary.

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PubMed2004

MDCT of the proximal anastomoses created by nitinol implants in coronary artery bypass grafting: a retrospective two-observer evaluation.

The purpose of this study was to investigate the proximal anastomosis of CABG grafts created by a nitinol aortic connector. After receiving CABG, 33 patients underwent CT examination of the heart. On the same patients, CT was performed on postoperative day 5 (4-row CT, group A) and again 1 year thereafter (16-row CT, group B). Twenty-three ACVB to RCX and 27 ACVB to RCA grafts were included. Every anastomosis was reviewed under different reformations (MIP, MPR and VRT). Interobserver correlation was determined. Five days postoperatively, 48/50 anastomoses were classified as patent. One year postoperatively, 42/50 anastomoses were classified as patent. In both groups, the aortic connector could be visualized with good quality: 1.82+/-1.10 (group A) and 1.93+/-1.22 (group B) for ACVB to RCA, similar results for ACVB to RCX grafts (MPR). Image quality at the aortic connector site did not display a significant difference for any reformation between groups (P>0.05). Within groups, MPR displayed better visualization than MIP and VRT (P<0.05). In the presence of metal implants, CT provides reliable data in evaluation of the proximal anastomosis. Sixteen-row CT does not bring a significant benefit to image quality. MPR displayed the best visualization within both groups.

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PubMed2004

Visualisation of non-invasive coronary bypass imaging: 4-row vs. 16-row multidetector computed tomography.

UNLABELLED: The purpose of this study was to investigate the image quality of coronary artery bypass graft visualization in 4- and 16-row multidetector CT using multiple imaging reformations. MATERIAL AND METHODS: One hundred sixteen patients underwent CT examination of the heart after receiving CABG. Group A (n=58) received 4-row MDCT; group B (n=58) received 16-row MDCT. Various bypass types such as LITA to LAD and venous grafts to the RCA and RCX were included in the study. A five-point Likert scale was used to grade image quality. Each bypass was reviewed under different imaging reformations: thin slap maximum intensity projection (MIP thin), multiplanar reformation (MPR) and volume rendering technique (VRT). Special attention was paid to the delineation of the distal anastomosis. Interobserver correlation was determined. RESULTS: From 289 bypass grafts examined, 279 (96.54%) were classified as patent and 10 (3.46%) as not patent. Except for the distal anastomosis, 16-row MDCT showed significantly better results for all segments of bypasses. Comparison of reformations within group A and B showed that MIP thin (P<0.05) and VRT (P<0.05) displayed better visualization as compared to MPR. CONCLUSION: Significantly better imaging of all bypass types is possible using 16-row MDCT as compared to 4-row MDCT. Assessment of the distal anastomosis yields no difference between 4- and 16-row technology.

Adult↗

PubMed2004

Automatic connector devices for proximal anastomoses do not decrease embolic debris compared with conventional anastomoses in CABG.

OBJECTIVE: Emboli generated during cardiac surgery have been associated with aortic clamping and manipulation. Proximal anastomotic devices are thought to be less traumatic by eliminating partial clamping, potentially resulting in fewer adverse outcomes. Intra-aortic filtration has been shown to effectively capture particulate debris. We compared the amount of debris released using intra-aortic filtration and the clinical outcomes between conventionally handsewn and automated proximal anastomoses. METHODS: Seventy-seven patients undergoing primary coronary artery bypass grafting with cardiopulmonary bypass were enrolled in a prospective randomized study. Patients were assigned to the anastomotic device Group I (Symmetry Aortic Connector, n = 39) or the conventional handsewn anastomosis control Group II (n = 38). Proximal anastomoses were performed before cardiopulmonary bypass in both groups. Intra-aortic Filter 1 (EMBOL-X)was deployed prior to partial clamping or puncturing the aorta for device application and removed after the proximal anastomosis was completed. Prior to cross-clamp removal, a second filter was inserted (Filter 2). A core laboratory performed quantitative and histologic analyses of the debris captured. Clinical outcomes included adverse events, neurocognitive test scores, graft patency, and mortality. RESULTS: Preoperative variables and risk factors were not significantly different between Groups I and II (EuroSCORE 3.9+/-2.6 vs. 4.2+/-2.5). Filter analyses showed no significant difference between Groups I and II in Filter 1 or 2 for either surface area of particles or total number of particles (P> 0.005). There was a significant decrease between Filters 1 and 2 in both Groups for surface area of particles (Group I: 18.5+/-23.8 mm2 vs. 10.7+/-16.3 mm2, P = 0.017; Group II: 15.0+/-15.4 mm2 vs. 6.9+/-.6.5 mm2, P = 0.004), and for total number of particles in Group II (8.6+/-3.7 vs. 7.1+/-2.4, P = 0.023). No significant differences were observed between Group I (device) and Group II (control) outcomes for myocardial infarction, neurocognitive deficit, stroke, length of stay, graft occlusion, or mortality. CONCLUSIONS: The application of proximal aortic connectors without partial clamping does not reduce particulate emboli or affect clinical outcomes compared with conventional anastomoses. Cross-clamping during cardiopulmonary bypass produces less particulate debris than conventional or automated proximal anastomoses performed off-pump, suggesting a major source of emboli is the anastomotic process.

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PubMed2003

Emergent endovascular stent grafting for perforated acute type B dissections and ruptured thoracic aortic aneurysms.

BACKGROUND: The purpose of our study was to demonstrate the effectiveness of endovascular stent grafts in the treatment of acutely ruptured thoracic aortic aneurysms and type B dissections as an alternative to the conventional surgical approach in an emergency setting. METHODS: From January 2001 to October 2001, we deployed 11 emergent endovascular stent grafts into the thoracic aorta. We treated seven ruptured aortic aneurysms and four acutely perforated type B dissections. Aortic rupture was confirmed preoperatively by spiral computed tomography. In all cases, hemothorax was present. The average interval from onset of symptoms to treatment was 28.5 hours. We used nine Talent and two Excluder stent grafts. RESULTS: Deployment of the stent grafts was successful in nine cases. There were two cases of access failure due to small caliber of iliac arteries, and 1 of these patients died shortly after the procedure was abandoned, At 12 months of follow-up, there were no cases of paraplegia, stent migration, or endoleaks. There was, however, one temporary renal failure, and 2 patients required mechanical ventilation for more than 48 hours. CONCLUSIONS: Our experiences with emergency endovascular stent grafting show that the procedure is technically feasible, with less morbidity and mortality than conventional open surgery, in high-risk patients.

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PubMed2003

Surgical versus endovascular treatment of acute thoracic aortic rupture: a single-center experience.

BACKGROUND: Surgical management of acute thoracic aortic ruptures is controversial, especially in patients with preexisting comorbidities; associated mortality and paraplegia rates remain high. It was our objective to evaluate whether treating these patients acutely with endovascular stent grafts would improve their outcome. METHODS: From November 1999 to February 2002 a total of 54 patients, age 28 to 83 years, were admitted to our institution with an acute rupture of the thoracic aorta (24 ruptured aneurysms, 14 perforated type B dissections, 16 traumatic ruptures). Twenty-eight patients were managed surgically using cardiopulmonary bypass (group 1), and 26 patients were treated acutely with an endovascular stent graft (group 2). The resuscitation protocol and interval from onset of symptoms to treatment was comparable in both groups. Medical records were reviewed for prehospitalization and emergency department data, operative findings, and outcomes. RESULTS: There were 5 of 28 deaths (17.8%) in the surgical group and 1 of 26 deaths (3.8%) in the endovascular group. In the surgical group 1 of 28 patients (3.6%) exhibited paraplegia; there were no cases of paraplegia in the endovascular group. There were 4 of 28 cases (14.3%) of renal failure in group 1 and 1 of 26 (3.8%) in group 2. In group 1, 8 patients (28.6%) required mechanical ventilation for more than 48 hours; there were 2 of 26 patients (7.7%) in group 2 with this ventilatory requirement. Three patients required a repeat thoracotomy for hemorrhage in the surgical group. There were two access failures in the endovascular group. CONCLUSIONS: In the treatment of acute ruptures of the thoracic aorta, the immediate outcome of patients treated with endovascular stent grafts appears to be better than with management by conventional surgical repair.

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PubMed2003

The clamshell approach for the treatment of extensive thoracic aortic disease.

OBJECTIVE: Management of extensive thoracic aortic disease may present an immense technical challenge. The choice of surgical access and subsequent exposure determines whether a single-stage or a 2-stage approach can be adopted. METHODS: Fifteen patients with extensive thoracic aortic disease underwent resection of the ascending aorta, the aortic arch, and varying segments of the descending aorta. Four patients had concomitant coronary artery bypass grafting and 3 patients had aortic valve reconstruction. All patients were treated with a single-stage approach via a bilateral anterior thoracosternotomy (clamshell incision). RESULTS: There was 1 hospital death (6.6%). Two patients required reoperation for bleeding (13.3%). Two patients needed mechanical ventilation for more than 48 hours. Three patients suffered a stroke (20%). Two patients (13.3%) had transient neurologic dysfunction. None of the patients had renal failure. There were no wound infections in this group. CONCLUSION: The single-stage approach, via a clamshell incision, is a safe and effective procedure for patients who require treatment of extensive thoracic aortic disease and concomitant cardiac lesions.

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PubMed2003

Cariporide (HOE642) limits S-100B release during cardiac surgery.

Cardiac surgery with cardiopulmonary bypass (CPB) results in transient cerebral swelling in most patients. Cognitive decline occurs in 24-57% of patients and 2-5% experience stroke. Serum levels of S-100B, a potential marker of increased blood-brain barrier permeability, increase during and early after surgery. The authors studied the effects of the novel Na /H exchange inhibitor cariporide (HOE642) on postoperative serum levels of S-100B and neuron-specific enolase (NSE) in 53 patients at high risk undergoing coronary artery bypass grafting. Patients were randomly assigned to one of four groups: I, placebo; II, 20 mg cariporide; III, 80 mg cariporide; IV, 120 mg cariporide). In addition, the leukocyte activation marker myeloperoxidase (MPO) and malondialdehyde (MDA), a marker for lipid peroxidation, were evaluated by enzyme-linked immunoassay. Postoperatively, five patients experienced transient ischemic attack or stroke. S-100B levels increased from 0.43 microg/l +/- 0.33 before operation to 2.27 microg/l +/- 0.69 1 hour after surgery in the placebo group. Preoperative S-100B levels in the HOE642 groups did not differ from the placebo group whereas, 1 hour after surgery, levels were significantly lower in groups II, III, and IV (1.63 microg/l +/- 0.2, 1.27 microg/l +/- 0.27, and 0.90 microg/l +/- 0.21, respectively). NSE, MPO, and MDA serum levels did not differ among groups. These findings may stimulate larger clinical studies to examine the effects of HOE642 on cerebral swelling and neurologic/cognitive outcome of cardiac surgery with CPB.

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PubMed2003

Emergent endovascular interventions for contained rupture of thoracic aortic aneurysms.

BACKGROUND: The purpose of our study was to assess in an emergency setting the feasibility of endovascular stent graft treatment of contained ruptures of thoracic aortic aneurysms. METHODS: Seven patients with contained ruptures of thoracic aortic aneurysms from a series of 54 endovascular interventions were treated by the deployment of an aortic stent graft. In all cases, hemothorax was present. Acute deployment was performed with the patient under general anesthesia, and access was gained via the common femoral or iliac arteries. After a follow-up o f 12 months, the patients were evaluated by computed tomography. RESULTS: One patient died perioperatively. The procedure was technically successful in 5 patients. Perioperatively and at follow-up, there were no cases of paraplegia, stent graft migration, or endoleaks. There were, however, 2 cases of access failure, 1 case of temporary renal failure, and 2 patients who required prolonged mechanical ventilation. CONCLUSION: The acute treatment of contained ruptures of thoracic aortic aneurysms is feasible. This form of treatment seems to be a promising option in the treatment of these high-risk patients.

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PubMed2003

Ultrafast computed tomography for quality control of automated proximal anastomoses.

BACKGROUND: The Symmetry aortic connector uses a nitinol implant to create proximal anastomoses with saphenous vein grafts. Multiple detector-row cardiac computed tomography (MDCT) is used as a noninvasive method of quality control at our institution. METHODS: In 50 elective coronary artery bypass grafting patients who participated in a randomized trial comparing automated with conventionally hand-sewn proximal anastomoses, MDC T was performed on postoperative day 5. Fifty-three automated Symmetry anastomoses were created in 34 patients (group 1). Twenty-five conventionally hand-sewn anastomoses created in 16 patients served as controls (group 2). Graft patency and the presence or absence of high-grade stenosis at the proximal anastomotic site were evaluated. RESULTS: In group 1, 2 (3.8%) of the grafts were found occluded at MDCT or coronary angiography, and no further relevant stenosis was observed. In group 2, at postoperative MDCT all grafts were found patent without significant narrowing of the proximal anastomotic site. CONCLUSIONS: The feasibility of proximal anastomoses using the Symmetry device has been reported. Patency control with invasive angiography has been performed by other groups. With MDCT, noninvasive evaluation of proximal anastomotic quality and graft patency is possible, even if nitinol is implanted.

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PubMed2002

The Heartflo device for distal coronary anastomoses: clinical experiences in 60 patients.

BACKGROUND: The Heartflo anastomotic device automates the suturing process with simultaneous delivery of 10 standard polypropylene sutures through the graft and the coronary vessel wall to construct the anastomosis. We performed clinical testing in 60 patients undergoing coronary artery bypass grafting. METHODS: One automated distal coronary anastomosis was initially placed in each patient, the other anastomoses were created with standard running sutures. After a "flat foot"-shaped prototype was deployed in 30 patients (group I), the design of the foot was modified and deployment of the new device performed in the next 30 patients (group II). RESULTS: In group I, automated anastomoses were completed in 16 patients (53%) using 1.7 +/- 1 additional stitches. In 26 group II patients (86%), a hemostatic anastomosis using 1.2 +/- 1 additional stitches was achieved. Anastomoses were completed in 19.0 +/- 3 minutes in group I and in 15.6 +/- 2 minutes in group II. CONCLUSIONS: We have shown the feasability of coronary anastomoses using the Heartflo device. The modified version improved tissue capture, resulting in a higher rate of completed anastomoses. Because anastomotic time is still prolonged, an easier suture management is mandatory in the next developmental step.

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PubMed2002

Vacuum-assisted suction drainage versus conventional treatment in the management of poststernotomy osteomyelitis.

OBJECTIVE: The purpose of our study was to compare vacuum-assisted suction drainage (VASD) to conventional wound management, in the treatment of poststernotomy osteomyelitis (SOM). METHODS: We included a total of 42 patients that developed poststernotomy osteomyelitis and required open wound management, between 1998 and 2000, in this study. Twenty of these patients were treated by VASD and the other 22 by conventional wound management. The patients were well comparable with regards to age, presenting postoperative day, infecting organism and risk factors for osteomyelitis. This was a retrospective study. RESULTS: The patients treated by VASD had a significantly reduced treatment duration (mean 17.2+/-5.8 vs. 22.9+/-10.8 days, P=0.009) and total hospital stay (mean 27.2+/-6.5 vs. 33.0+/-11.0 days, P=0.03). Perioperative mortality was similar, with one early death in each group. CONCLUSION: We conclude from our experience in the treatment of 42 patients with poststernotomy osteomyelitis that VASD shortened wound healing and hospital stay and thus proved to be an excellent alternative to conventional open management of these wounds.

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PubMed2002

Emergency endovascular interventions for ruptured thoracic and abdominal aortic aneurysms.

BACKGROUND: The purpose of our study was to show the effectiveness of endovascular stent grafts in the treatment of acutely ruptured abdominal and thoracic aortic aneurysms as an alternative to the conventional surgical approach in an emergency setting. METHODS: From October 1996 to October 1998 we deployed 9 emergent endovascular stent grafts--6 in the abdominal aorta and 3 in the thoracic aorta. Aortic rupture was confirmed before surgery with spiral-computed tomographic scan. The average interval from onset of symptoms to treatment was 4.5 hours. We used commercially manufactured stent grafts: 4 Corvita (Corvita Inc/Schneider Corp/Boston Scientific Corp, Natick, Mass), 3 Talent (World Medical Inc, Surise, Fla/Medtronic, Sunnyvale, Calif), and 2 Vanguard (Boston Scientific Corp, Natick, Mass). RESULTS: Deployment of the stent grafts was successful in all cases. Two patients died in the follow-up period (120 months) from myocardial infarction. No cases were seen of paraplegia or stent migration. However, 2 endoleaks, 1 in-stent stenosis, 1 temporary renal failure, and 1 brief episode of myocardial ischemia occurred. CONCLUSION: Our experiences with emergency endovascular stent grafting show that the procedure is technically feasible, with less morbidity and mortality than conventional open surgery, in selected patients.

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