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Biomedical subjects

F Vermeulen

Publications and source records attributed to F Vermeulen.

8 recordsLinked to original sources
PubMed1992

The Intact porcine bioprosthesis: early world-wide clinical experience and analysis of a single institution's experience.

The Intact porcine bioprosthesis is a new-generation valve fixed under stress-free conditions and subjected to a mineralization-inhibiting treatment. The valve is undergoing multi-centre prospective clinical evaluation sponsored by Medtronic, Inc., with 19 centres participating world wide. Since April 1986, 1465 valves have been implanted in the aortic position (AVR, n = 965), mitral position (MVR, n = 438), or both (n = 62), and followed up to 5 years. The data recorded at our participating centre, with 115 valves implanted (AVR n = 93, MVR n = 22) closely match the overall event and death rates in the prospective study. Early mortality in the overall study is 5.6% in AVR and 6.6% in MVR; 3-year actuarial survival rates are 88.5% in AVR and 85.6% in MVR; structural valve-failure-free rates at 3 years are 99.8% in AVR and 98.5% in MVR; 3-year freedom from valve-related reoperation is 97.3% in AVR and 95.8% in MVR. The preferential use of bioprosthetic valves in patients aged 70 years and older with no other indication for anticoagulant treatment entails the not infrequent occurrence of patient/prosthesis mismatch in AVR. Hence, when implanting bioprostheses in old patients, the acceptance of some mismatch has to be weighed against the freedom from anticoagulation treatment and the expected long-term freedom from structural valve failure. Further long-term follow-up will be required to demonstrate the greater durability expected from the stress-free fixation and the anti-mineralization treatment.

Actuarial Analysis↗
PubMed1991

Measured attenuation correction using the Maximum Likelihood algorithm.

Quantitative determination of local radioactivity concentration in positron emission tomography (PET) requires a good attenuation correction procedure to reconstruct the emission image. Using a similar Maximum Likelihood (ML) algorithm as for the reconstruction of the emission image, a method is proposed to reconstruct a transmission image, i.e. a map of absorption coefficients. This reconstructed transmission image is then used to calculate the attenuation correction factors needed for the ML reconstruction of the emission image. This approach takes automatically into account the convolution step in the acquisition process (caused by various smoothing factors, e.g. the detector width). This results in appreciable noise suppression without loss of resolution due to filtering, thus making the reconstructed images easier to interpret. A comparison is made with other estimates for the measured attenuation correction using phantom studies.

Algorithms↗
PubMed1990

Intraoperative transesophageal color-coded Doppler echocardiography for evaluation of residual regurgitation after mitral valve repair.

Because mitral valve competence after mitral valve reconstruction is awkward to assess during this procedure, we evaluated in this respect transesophageal color-coded Doppler echocardiography in 23 patients undergoing mitral valve reconstruction for severe mitral regurgitation. Transesophageal echocardiographic examinations were performed after induction of anesthesia but before sternotomy (baseline), after mitral valve repair before decannulation, and at sternal closure, all at similar mean aortic pressure and echocardiographic instrument settings. The degree of mitral regurgitation by transesophageal color Doppler flow mapping was visually quantified on a 5-point scale (0 to 4), pending the left atrial extent of the regurgitant jet. This was compared with the degree of mitral regurgitation by left ventricular cineangiography performed within several weeks after operation and also visually quantified on a 5-point scale (0 to 4), with use of the right anterior oblique projection. There was good correlation between the two methods (r = 0.83; p less than 0.001). We conclude that residual mitral regurgitation, as assessed by transesophageal color flow mapping in the operating room, highly correlates with the ultimate mitral regurgitation by cineangiography. Therefore transesophageal echocardiography can be helpful for evaluation of mitral valve competence during mitral valve reconstruction, and hence, in case of repair failure, allow valve replacement in the same surgical session, thus avoiding reoperation.

Adolescent↗
PubMed1989

Surgical correction of descending thoracic aortic aneurysms with shunt or bypass techniques versus simple aortic cross-clamping.

Between June, 1972, and January, 1986, 57 patients underwent resection of a descending thoracic aortic aneurysm using a shunt or bypass for distal aortic perfusion (group I, n = 29) or simple aortic cross-clamping, routinely used since mid-1983 (group II, n = 28). There was a statistically significant difference in the mean age of the patients: in group II it was 14 years higher than in group I (group I: 52.8 years, group II: 66.5 years). Of these 57 patients, 8 died in hospital (group I: 6 patients, group II: 2 patients). Hospital mortality was strongly related to preoperative rupture and the incidence of intraoperative complications. Postoperative paraplegia occurred in 3 patients, all in group I, and could be related to ligation of four or more intercostal arteries between T8 and T12. Postoperative renal failure, necessitating dialysis in 5 patients, was strongly related to intraoperative hypotension, and also to emergency procedures and pre-existing renal dysfunction. Intraoperative haemorrhage occurred more often using shunting or bypass techniques. Mortality, paraplegia and renal failure showed a decreasing trend after abandoning the use of adjunctive perfusion.

Acute Kidney Injury↗
PubMedDate not supplied

[Presence of extracranial cerebral arterial lesions in patients undergoing open heart surgery: a planned approach to a single stage operation (author's transl)].

The combined approach of extracranial arterial lesions in patients undergoing open heart surgery decreases the high cardiac and neurological morbidity and mortality presented by patients operated sequentially. Besides the anatomically sound simultaneous approach of arch lesions and heart surgery, both to be operated by median sternotomy, the authors present their criteria used in the selection of neurologically symptomatic and asymptomatic patients with carotid and vertebral disease to be operated simultaneously. Results in 17 personal cases are presented.

Aorta, Thoracic↗