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Biomedical subjects

Roman Pfitzner

Publications and source records attributed to Roman Pfitzner.

8 recordsLinked to original sources
PubMed2004

[Low ejection fraction as risk factor after aortic valve replacement].

UNLABELLED: The aim of the study is to estimate the operative risk of aortic valve replacement for severe aortic valve stenosis in patients with distinctly impaired left ventricular function (ejection fraction below 40%). From the population of 2512 pts, who underwent aortic valve replacement in the years 1990 to 1999 because of acquired malformation, a group of 108 pts (4.3%), fulfilling the above mentioned conditions was selected. Between them prevailed men, 92 (85.2%), and the average age was 53.4 +/- 14.5. All pts remained in the NYHA functional class III/IV. The average ejection fraction was estimated 28.2 +/- 14.3%. The pts demonstrated concentric left ventricular hypertrophy, severe aortic valve calcifications, the average valvular area was 0.91 cm2, and the pressure gradient over the valve was 71 +/- 44 mmHg. The pts were operated on by different surgeons but after the same protocol of extracorporeal circulation and cardioplegia administration. Low output syndrome occurred in ca 40% of pts, and cardiac failure was the main cause of death. The hospital mortality was 8.6%, and it was over two times higher then the whole population of pts, who underwent aortic valve replacement. All survivors (91.4%) demonstrated clinical improvement already during the early observation. CONCLUSIONS: Low ejection fraction is an important risk factor of surgery for aortic valve stenosis. However, the elevated operative mortality, comparable to other institutions, may be accepted taking for consideration, that surgery is the only way of treatment and improvement may be expected in about 90% of pts, including anatomical and hemodynamic parameters, as well as life longevity and comfort. In the extreme cases the HTX should be considered.

Adult↗
PubMed2003

[Asymptomatic carotid stenosis: ACS].

Asymptomatic carotid stenosis (ACS) is the lesion located in the vicinity of the common carotid artery branching, without neurological symptoms caused by insufficient blood flow to the brain. Cerebrovascular diseases represent an important medical as well as social problem, since this is one of the leading causes of mortality and serious invalidity worldwide. Majority of brain insults are caused by stenosing atherosclerotic lesions of the carotid arteries. Thus, early surgical treatment may contribute to lessen this problem. Routine diagnosis of ACS include auscultation and ultra-sonographic examination of carotid arteries. Early detection of the disease enables proper medical prophylaxis and decision for surgical treatment (providing that expected benefit for the patient exceeds possible operative risk, i.e. < 3% of complication rate in experienced surgical wards). That's why of particular importance is to formulate multidisciplinary programs of insult prevention and to conduct multiinstitutional studies in order to establish clear cut indications for surgical treatment, particularly for the group of asymptomatic patients.

Carotid Stenosis↗
PubMed2003

Mineralization and organic phase modifications as contributory factors of accelerated degeneration in homograft aortic valves.

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess histological and mineralogical properties of leaflets in human, antibiotic-preserved aortic homograft valves (recovered during surgical replacement) in order to identify factors accounting for pathological changes leading to accelerated graft dysfunction. A comparison was made with aortic valves prepared for grafting, with a view to assessing morphological and mineralogical characteristics as a potential preimplantation risk factor. METHODS: Valve leaflets were examined with light and scanning electron microscopy. Mineralization was assessed histochemically, and also physicochemically by atomic absorption spectroscopy (AAS). RESULTS: All explanted homograft valve leaflets revealed prominent degenerative changes seen as decreased surface area, fibrosis, mineralization and focal thrombosis. Substantial loss of endothelium and fibroblasts, reduced collagen bundles crimping, inflammation (81%) and disappearance of layered structure (59%) was identified. The elastic elements were relatively stable, though a gradual age-dependent loss was observed in both groups. Accelerated mineralization was seen in all explanted homografts; inorganic deposits were composed mainly of hydroxyapatite. Two types of mineralization were identified: large limited nodular structures, and diffuse mineral deposits. Homografts with moderately elevated mineralization, well-preserved layered structure and sporadic infective changes proved to have the greatest durability. Homograft durability was also affected by the difference in host and donor age. CONCLUSION: Preimplantation factors affecting pathological changes determining homograft durability included morphological status of the graft itself and donor age; host-related factors included recipient age, endocarditis, native valve calcification, and host-donor matching (age difference between host and donor). A limited molecular mineralization may increase valvular durability, provided that no focal nodular calcifications exist that might adversely affect overall homograft integrity.

Adult↗