Karel Klop
Erasmus University Rotterdam
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Karel Klop.
Transplantation | 2014
Leonienke F. C. Dols; Niels F.M. Kok; Frank d'Ancona; Karel Klop; T.C. Tran; Johan F. Langenhuijsen; Türkan Terkivatan; Frank J. M. F. Dor; Willem Weimar; Ine M. M. Dooper; Jan N. M. IJzermans
Background Laparoscopic donor nephrectomy (LDN) has become the gold standard for live-donor nephrectomy, as it results in a short convalescence time and increased quality of life. However, intraoperative safety has been debated, as severe complications occur incidentally. Hand-assisted retroperitoneoscopic donor nephrectomy (HARP) is an alternative approach, combining the safety of hand-guided surgery with the benefits of endoscopic techniques and retroperitoneal access. We assessed the best approach to optimize donors’ quality of life and safety. Methods In two tertiary referral centers, donors undergoing left-sided nephrectomy were randomly assigned to HARP or LDN. Primary endpoint was physical function, one of the dimensions of the Short Form-36 questionnaire on quality of life, at 1 month postoperatively. Secondary endpoints included intraoperative events and operation times. Follow-up was 1 year. Results In total, 190 donors were randomized. Physical function at 1 month follow-up did not significantly differ between groups (estimated difference, 1.79; 95% confidence interval, −4.1 to 7.68; P=0.55). HARP resulted in significantly shorter skin-to-skin time (mean, 159 vs. 188 min; P<0.001), shorter warm ischemia time (2 vs. 5 min; P<0.001) and a lower intraoperative event rate (5% vs. 11%, P=0.117). Length of stay (both 3 days; P=0.135) and postoperative complication rate (8% vs. 8%; P=1.00) were not significantly different. Potential graft-related complications did not significantly differ (6% vs. 13%; P=0.137). Conclusions Compared with LDN, left-sided HARP leads to similar quality of life, shorter operating time, and warm ischemia time. Therefore, we recommend HARP as a valuable alternative to the laparoscopic approach for left-sided donor nephrectomy.
Transplantation | 2012
Karel Klop; Leonienke F. C. Dols; Niels F.M. Kok; Willem Weimar; Jan N. M. IJzermans
Background The increasing number of living kidney donors in the last decade has led to the development of novel surgical techniques for live-donor nephrectomy. The aim of the present study was to evaluate the current status of the surgical approach in Europe. Methods A survey was sent to 119 transplant centers in 12 European countries. Questions included the number of donors, the technique used, and the acceptance of donors with comorbidities. Results Ninety-six centers (81%) replied. The number of living donors per center ranged from 0 to 124. Thirty-one institutions (32%) harvested kidneys using open techniques only. Six centers (6%) applied both endoscopic and open techniques; 59 centers (61%) performed endoscopic donor nephrectomy only. Lack of evidence that endoscopic techniques provide superior results was the main reason for still performing open donor nephrectomy. In seven centers, a lumbotomy is still performed. Seventy-two centers (75%) accept donors with a body mass index of more than 30 kg/m2, the median upper limit in these centers was 35 kg/m2 (range, 31–40). Donors with an American Society of Anesthesiologists classification higher than 1 were accepted in 55% of the centers. Conclusions Live kidney donation in general and minimally invasive donor nephrectomy in particular are more commonly applied in Northern and Western Europe. However, a classic lumbotomy is still performed in a minority of centers. Because minimally invasive techniques have been proven superior, more attention should be given to educational programs in this field to let many kidney donors benefit.
Transplantation | 2012
Inez K. B. Slagt; Karel Klop; Jan N. M. IJzermans; Türkan Terkivatan
&NA; Urological complications are still a major problem postoperatively with a reported incidence of up to 30%, associated with significant morbidity, mortality, prolonged hospital stay and high medical costs. To date, there is no evidence favouring either an extravesical or an intravesical approach. The purpose of this systematic review and meta-analysis is to determine if an intravesical or extravesical anastomosis in kidney transplantation is to be preferred. Comprehensive searches were conducted in PubMed, Embase and the Cochrane Library. Reference lists were searched manually. The methodology was in accordance with the PRISMA statement. Two randomized controlled trials and seventeen cohort studies were identified. Based on the meta-analysis, outcome was in favour of the extravesical anastomosis. A relative risk (RR) for stenosis of 0.67 (confidence interval (CI), 0.48–0.93; p = 0.02), for leakage 0.55 (CI 0.39–0.80; p = 0.001) for the total number of urological complications 0.56 (CI 0.41–0.76; p < 0.001) and for haematuria of 0.41 (CI 0.22–0.76; p = 0.005) was demonstrated. Based on our results, we conclude that there is evidence in favour of the extravesical ureteroneocystostomy for having a smaller amount of urological complications in kidney transplantation.
Transplantation | 2013
Karel Klop; Leonienke F. C. Dols; Willem Weimar; Ine M. M. Dooper; Jan N. M. IJzermans; Niels F.M. Kok
Background Expanding the use of elderly live donors may help meet the demand for kidney transplants. The aim of this study was to quantify the effect of the surgical procedure on the quality of life (QOL) of elderly donors compared with younger donors. Methods Alongside three prospective studies (two randomized) running between May 2001 and October 2010, we asked 501 live donors to fill out the Short Form-36 questionnaire preoperatively and at 1, 3, 6, and 12 months postoperatively. We defined live donors 60 years or older as elderly. Between-group analyses regarding QOL were adjusted for baseline values and gender. Results One hundred thirty-five donors were older and 366 donors were younger than 60 years. The response rate was high, with 87% at 12 months postoperatively. Elderly donors less often scored as American Society of Anaesthesiology classification 1 (60% vs. 81%; P<0.001) indicating a higher rate of minor comorbidity. At 1 month postoperatively, between-group analysis showed a significant advantage in QOL in favor of the elderly group regarding the dimensions “bodily pain” (7 points; P=0.001), “role physical” (18 points; P<0.001), and “vitality” (5 points; P=0.008). At 3 months, “bodily pain” (3 points, P=0.04) and “role physical” (8 points, P=0.02) were still in favor of the older group. At 6 and 12 months, “physical function” was in favor of the younger group (3 and 5 points, respectively; P=0.04 and P<0.001). Conclusions This study demonstrates that elderly donors recover relatively fast. The perspective of excellent postoperative QOL may help convince elderly individuals to donate.
Transplant International | 2015
Shiromani Janki; Karel Klop; Ine M. M. Dooper; Willem Weimar; Jan N. M. IJzermans; Niels F.M. Kok
Previously reported short‐term results after live kidney donation show no negative consequences for the donor. The incidence of new‐onset morbidity takes years to emerge, making it highly likely that this will be missed during short‐term follow‐up. Therefore, evidence on long‐term outcome is essential. A 10‐year follow‐up on renal function, hypertension, quality of life (QOL), fatigue, and survival was performed of a prospective cohort of 100 donors. After a median follow‐up time of 10 years, clinical data were available for 97 donors and QOL data for 74 donors. Nine donors died during follow‐up of unrelated causes to donation, and one donor was lost to follow‐up. There was a significant decrease in kidney function of 12.9 ml/min (P < 0.001) at follow‐up. QOL showed significant clinically relevant decreases of 10‐year follow‐up scores in SF‐36 dimensions of physical function (P < 0.001), bodily pain (P = 0.001), and general health (P < 0.001). MFI‐20 scores were significantly higher for general fatigue (P < 0.001), physical fatigue (P < 0.001), reduced activity (P = 0.019), and reduced motivation (P = 0.030). New‐onset hypertension was present in 25.6% of the donors. Donor outcomes are excellent 10 years post‐donation. Kidney function appears stable, and hypertension does not seem to occur more frequently compared to the general population.
American Journal of Transplantation | 2015
Shiromani Janki; D. Verver; Karel Klop; A.L. Friedman; T. G. Peters; Lloyd E. Ratner; Jan N. M. IJzermans; Frank J. M. F. Dor
In 2006, a survey from the American Society of Transplant Surgeons disclosed significant and sometimes fatal hemorrhagic events in live donor nephrectomies (LDN) related to failure of clips, leading to the contraindication of the Weck® Hem‐o‐lok® clip for control of the renal artery during LDN. A survey regarding vascular control techniques, their perceived safety ratings and their failures was sent to 645 European Society for Organ Transplantation members who profiled their profession as “surgeon” and selected “kidney” as organ type. Two hundred forty‐three (41%) members responded, of whom 171 (63.3%) independently perform LDN. Their responses were analyzed. For arterial and venous vascular control, the GIA™ and TA™stapler are used most frequently, and were rated the safest. Of the 121 reported hemorrhagic events, slippage and dislodgement of clips occurred at least 58 times, while stapler malfunction occurred at least 40 times. One donor death from hemorrhage related to clip dysfunction was reported. Hemorrhagic complications of LDN with fatal and non‐fatal outcomes still occur. Strikingly, many surgeons do not use the vascular closing technique that they consider most safe. Failure of non‐transfixion techniques is associated with greater risks for the donor. Control of major vessels in LDN must employ transfixion techniques for optimal donor safety.
Transplantation | 2013
Karel Klop; Niels F.M. Kok; Leonienke F. C. Dols; Frank d'Ancona; E.M.M. Adang; Janneke Grutters; Jan N. M. IJzermans
Background Live kidney donation has a clear economical benefit over dialysis and deceased-donor transplantation. Compared with mini-incision open donor nephrectomy, laparoscopic donor nephrectomy (LDN) is considered cost-effective. However, little is known on the cost-effectiveness of hand-assisted retroperitoneoscopic donor nephrectomy (HARP). This study evaluated the cost-effectiveness of HARP versus LDN. Methods Alongside a randomized controlled trial, the cost-effectiveness of HARP versus LDN was assessed. Eighty-six donors were included in the LDN group and 82 in the HARP group. All in-hospital costs were recorded. During follow-up, return-to-work and other societal costs were documented up to 1 year. The EuroQol-5D questionnaire was administered up to 1 year postoperatively to calculate quality-adjusted life years (QALYs). Results Mean total costs from a healthcare perspective were
Kidney International | 2012
Karel Klop; Oguzhan Karatepe; Jan J. Weening; Madelon van Agteren; Frank J. M. F. Dor
8935 for HARP and
Surgical Endoscopy and Other Interventional Techniques | 2013
Karel Klop; Farah Hussain; Oguzhan Karatepe; Niels F.M. Kok; Jan N. M. IJzermans; Frank J. M. F. Dor
8650 for LDN (P=0.25). Mean total costs from a societal perspective were
Transplantation | 2012
Karel Klop; F. Hussain; O. Karatepe; J. IJzermans; Frank J. M. F. Dor
16,357 for HARP and