Jaap Hamming

Publications (3)5.88 Total impact

• Article: Limited value of digital subtraction angiography in the evaluation of cell-based therapy in patients with limb ischemia.

  Robert B van Tongeren, Jaap F Hamming, Saskia le Cessie, Arian R van Erkel, J Hajo van Bockel
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  ABSTRACT: Cell-based therapy has been proposed as a novel strategy for patients with severe peripheral arterial disease by stimulating vascular growth. In clinical studies of this therapy, the emphasis has been on demonstrating recovery of clinical parameters, rather than on evaluation of blood flow recovery. Angiography is still the gold standard for the assessment of lower leg arteries. Therefore, we studied the usefulness of angiography in the evaluation of cell-based therapy. Sixteen patients with critical leg ischemia (ischemic rest pain or ulcers), or persistent (>12 months) profound disabling claudication were unilaterally treated with autologous bone marrow-derived mononuclear cells. Pre- and 6 months post-treatment digital subtraction angiographies (DSA) were assessed and compared in a blinded fashion twice by a panel of seven vascular surgeons and interventional radiologists. Inter- and intraobserver variability on qualitative (poor/moderate/rich) and semi-quantitative (increase/no difference/decrease) assessment of collateral circulation were evaluated. Agreement was expressed inter- and intraclass correlation coefficients (CC). Inter- and intraobserver agreement was moderate for the qualitative grading of collateral extent (CC = 0.46 and 0.60, respectively). Agreement was moderate (inter-CC = 0.60) to good (intra-CC = 0.73) for comparing pre- and post-treatment DSA. Clinical response was based on limb salvage, pain-free walking distance, ankle-brachial pressure index and pain scores. No difference was observed in the extent of collateral circulation between pre- and post treatment DSA after separate analysis of clinical responding and non-responding patients (P = 0.92). DSA is not a suited modality for the evaluation of therapeutic angiogenesis.
  The international journal of cardiovascular imaging 09/2009; 26(1):19-25. · 2.15 Impact Factor
• Article: Ultrasonography and clinical observation in women with suspected acute appendicitis: a prospective cohort study.

  Pieter Poortman, Henk Oostvogel, Paul Lohle, Miguel Cuesta, Elly de Lange-de Klerk, Jaap Hamming
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  ABSTRACT: It was the aim of this study to evaluate the role of ultrasonography (US) and clinical observation in non-pregnant women of reproductive age with suspected appendicitis. In a prospective cohort study, US was performed in 234 women with suspected appendicitis. Based on US findings and clinical assessment, 3 patient categories were established. Group A: unequivocal signs--laparoscopy (regardless of US results); group B: equivocalsigns--positive US--laparoscopy; group C: equivocal signs--negative US--observation. US results were compared with surgery, observation and follow-up as the reference standard. The percentages of macroscopically infected appendices at laparoscopy in groups A, B and C were 76, 55 and 5%, respectively. Group A: US was false negative in 27 of 128 women (21%) and false positive in 12 of 40 women (30%). Group B plus C: US was false negative in 3 of 9 women (33%) and false positive in 5 of 57 women (9%). Forty-six of 55 patients (84%) completed observation. Because of a high false-negative rate, US as a sole imaging tool is of limited value both in women with unequivocal and equivocal signs of appendicitis. Observation is safe in women with equivocal signs of appendicitis.
  Digestive surgery 05/2009; 26(2):163-8. · 1.37 Impact Factor
• Source

  Available from: Dirk J Gouma

  Article: Surgical training in the Netherlands.

  Inne H M Borel-Rinkes, Dirk J Gouma, Jaap F Hamming
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  ABSTRACT: Surgical training in the Netherlands has traditionally been characterized by learning on the job under the classic master-trainee doctrine. Over the past decades, it has become regionally organized with intensive structural training courses, and a peer-based quality control system. Recently, the nationwide programme has been modernized further and now involves a systematic, competency-based education with structural training courses, formalized assessment and room for reflection by residents under the supervision of surgical teaching groups. To this end, a uniform web-based digital portfolio is being introduced to facilitate monitoring of the individual resident's progress. Though requiring inspirational leadership, commitment, and determination, this modernization has sparked enthusiasm among trainees and teachers.
  World Journal of Surgery 04/2008; 32(10):2172-7. · 2.36 Impact Factor