Biomedical subjects

Thorsten Walles

Publications and source records attributed to Thorsten Walles.

25 records · Page 2Linked to original sources

PubMed2003

In vivo model for cross-species porcine endogenous retrovirus transmission using tissue engineered pulmonary arteries.

OBJECTIVE: Acellularised porcine scaffolds have been successfully used for cardiovascular tissue engineering. However, there is concern about the possibility of porcine endogenous retrovirus (PERV) transmission. In this study we developed an in vivo model for cross-species PERV transmission. METHODS: In vitro autologous repopulated porcine pulmonary arteries (n=6) were implanted in sheep in orthotopic position. Blood samples were collected regularly up to 6 months after implantation and tested for PERV by means of polymerase chain reaction and reverse transcriptase-polymerase chain reaction. Explanted tissue engineered pulmonary arteries were tested for PERV sequences. RESULTS: PERV DNA was detectable in acellularised porcine scaffolds. No PERV sequences were detectable 6 months after implantation of in vitro repopulated acellularised porcine pulmonary arteries and in all tested peripheral blood samples. CONCLUSIONS: Acellularised porcine matrix scaffolds can be used for cardiovascular tissue engineering of autologous grafts without risk of PERV transmission.

Animals↗

PubMed2003

Chronic experiences with a single lead dual chamber implantable cardioverter defibrillator system.

Monitoring of atrial rhythm in patients implanted with ICDs may improve accuracy in identifying supraventricular arrhythmias and, therefore, prevent inappropriate therapies. Since difficulties were found in dual chamber ICDs with separate leads, a new designed single lead dual chamber ICD system was tested. Twenty-five patients implanted with a Deikos A+ (single coil defibrillation lead with two atrial sensing rings combined with a dual chamber ICD with a high amplifying atrial channel) were tested. Atrial and ventricular signals were analyzed during sinus rhythm (SR) and sinus tachycardias (STs), atrial flutter and AF, and VT or VF. Follow-ups were performed after 1, 3, 6, 9, and 12 months after implantation. Analysis of EGM amplitudes of stored episodes revealed that atrial signals during atrial flutter (2.1 +/- 0.51 mV) were comparable to those of ST (2.2 +/- 0.5 mV). Atrial amplitudes during AF were significantly lower (0.81 +/- 0.5 mV, P<0.01). During VF atrial "sinus" signals (2 +/- 0.8 mV) were stable. Ventricular parameters did not differ from a standard ICD lead; defibrillation threshold was 11.4 +/- 4.5 J (16 patients). During intraoperative and prehospital discharge measurements, 97.1% of SR-P waves and 99.2% of atrial flutter waves were detected correctly. In AF 91.11% of atrial signals were detected. Analysis of 505 stored episodes showed that 96.8% of ST and 100% of atrial flutter and 100% of AF episodes have been classified correctly and no underdetection of VT/VF was found. The first experiences with the new VDD-ICD system show an increase of the specificity to detect ventricular tachycardias to a level comparable to dual chamber ICDs with two leads. The reliability of this system has to be proven in a prospective randomized study.

Defibrillators, Implantable↗

PubMed2002

Combined correction of an adult scimitar syndrome and coronary artery bypass grafting.

Combined scimitar syndrome and coronary artery disease is a rare combination of congenital and acquired cardiac disease in adults. Hence, no guidelines for surgical correction are available. We report on the case of a 60-year-old man with coronary artery disease and scimitar syndrome. The patient underwent arterial coronary revascularization and simultaneous correction of the scimitar syndrome utilizing a new surgical approach with a modified pericardium-baffle reconstruction of the anomalous right pulmonary vein.

Combined Modality Therapy↗

PubMed2002

Results of valve-sparing aortic root reconstruction in 158 consecutive patients.

BACKGROUND: This study assesses the durability and clinical outcome of valve-sparing aortic root reconstruction using the reimplantation technique in a single center cohort. METHODS: From July 1993 to July 2001, 158 patients underwent replacement of the ascending aorta with native valve reimplantation. Mean age of patients was 52 +/- 17 years (9 to 84 years), 103 were men (65%). Thirty-four patients (22%) suffered from Marfan's syndrome. Aortic dissection Stanford type A was present in 29 patients (19%) (22 acute, 7 chronic), and concomitant partial or total arch replacement was necessary in 57 patients (36%). One or more additional procedures were performed in 28 patients (18%). Mean follow-up was 36 +/- 25 months (0.4 to 96 months). RESULTS: Thirty-day mortality was 3.8% (6 patients), but only 2.2% in elective patients. Mean bypass time was 169 +/- 50 minutes (99 to 440 minutes), aortic cross-clamp time was 129 +/- 31 minutes (79 to 205 minutes). In patients undergoing arch replacement, circulatory arrest was 26 +/- 18 minutes (7 to 99 minutes). During follow-up, there were 5 (3.3%) cardiac-related late deaths. Grade of aortic insufficiency (AI) decreased from 2.3 +/- 1.1 (0 to 4) preoperatively to 0.23 +/- 0.44 (0 to 2) postoperatively (p < 0.0001). Six patients required aortic valve replacement, 4 of those due to progressive AI. Average grade of AI increased significantly to 0.42 +/- 0.61 (0 to 3) at latest evaluation (p = 0.002). Two patients experienced a transient ischemic attack within the first postoperative week. No further thromboembolic complications were noticed. All patients presented with a favorable exercise tolerance. CONCLUSIONS: The aortic valve reimplantation technique achieves excellent clinical outcome with few complications even in complex pathologies. Lack of anticoagulation and favorable durability encourage wider and earlier use of this technique.

Adolescent↗

PubMed2002

Valve-sparing aortic root reconstruction in patients with significant aortic insufficiency.

BACKGROUND: To assess the feasibility and outcome of the valve-sparing aortic root reimplantation technique in patients with severe preoperative aortic insufficiency (AI). METHODS: Within 8 years we have operated on 158 patients with aneurysms of the ascending aorta using the reimplantation technique. We identified 83 patients with AI grade 3 or 4 (mean 3.1 +/- 0.4) preoperatively (study group). This cohort was compared with 71 patients with AI grade 2 or less (mean 1.3 +/- 0.9; control group) with regard to mortality, operative variables, complications, need for reoperation, postoperative AI, and clinical presentation during follow-up. RESULTS: Patient demographics were comparable in both groups. However, Marfan's syndrome (32% versus 13%, p = 0.006) and acute type A aortic dissection (20% versus 8.4%, p = 0.059) were more frequent in the control group. In addition, bypass (177 +/- 60 minutes versus 160 +/- 36 minutes, p = 0.022) and cross clamp times (133 +/- 34 minutes versus 124 +/- 27 minutes, p = 0.049) were significantly longer in controls. Mortality was low in the study group and comparable with controls (30-day, 3.6% versus 4.2%; during follow-up, 3.8% versus 5.9%; p = not significant [NS]). Reoperation rate was almost identical in both groups (3.8% versus 4.4%, p = NS). Mean grade of AI was significantly higher in the study group early postoperatively (0.31 +/- 0.46 versus 0.18 +/- 0.42, p = 0.049) but comparable at the last visit (0.43 +/- 0.58 versus 0.42 +/- 0.62, p = NS). During follow-up neither thromboembolic complications nor bleeding events were noted in either group. Clinical performance at the last visit revealed no significant difference between the groups. CONCLUSIONS: Preoperative severe aortic insufficiency does not impair the excellent outcome seen after a mean of 3 years of follow-up in patients undergoing the reimplantation technique for valve-sparing aortic root reconstruction.

Adolescent↗

PubMed2002

Paradoxic aortic arch embolization with occlusion of the supraaortic arteries.

Pulmonary embolization usually occurs when thrombotic material that originates from deep venous thrombosis of the lower extremities is washed out into the pulmonary vasculature via the blood stream. However, in the presence of a patent foramen ovale (PFO), systemic paradoxic embolization may also occur (Am J Surg 176 (1998) 158). Here, we report on the case of a patient with a PFO, who developed paradoxic embolization of the aortic arch following deep venous thrombosis and massive pulmonary embolism.

Aorta, Thoracic↗

PubMed2002

Massive postoperative rhabdomyolysis following combined CABG/abdominal aortic replacement: a possible association with HMG-CoA reductase inhibitors.

OBJECTIVE: The beneficial effects of the treatment of hyperlipidemia in the secondary prevention of ischemic heart disease are well established. Pravastatin is a 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitor often prescribed for the treatment of hypercholesterolemia. Occasional side effects include increased creatine kinase levels and myalgias worsened by exertion, rarely presenting with severe myopathy and rhabdomyolysis resulting in myoglobinuria and renal failure. PATIENTS AND METHODS: We report on a case of a 68-year-old male patient who developed rhabdomyolysis, severe myoglobinuria, and acute renal failure following uneventful coronary bypass grafting surgery (CABG) combined with infrarenal replacement of the abdominal aorta. The patient presented with numerous risk factors for development of rhabdomyolysis following surgical intervention. We underscore important contributory factors and discuss differential diagnostic considerations e.g., malignant hyperthermia and neuroleptic malignant syndrome in such patients. CONCLUSIONS: Considering the high risk of perioperative mortality in patients that routinely take fat lowering substances, we suggest to discontinue the intake prior to surgical interventions.

Acute Kidney Injury↗