Biomedical subjects
Publications and source records attributed to Patrick Peeters.
Acute interstitial nephritis (AIN) is a common cause of acute renal failure. We report a case of AIN, confirmed by renal biopsy, that developed in a patient with typhoid fever due to a Salmonella hadar infection. AIN secondary to Salmonella infection is a rare complication that has only been described twice in the literature. Salmonella should be added to the list of possible causes of AIN.
OBJECTIVE: Several prosthetic materials have been used for femoropopliteal bypass grafting in patients with peripheral vascular disease in whom a venous bypass is not possible. Expanded polytetrafluoroethylene (ePTFE) is the most commonly used, but patency results have not always equaled those achieved with vein, especially in below-knee reconstructions. This study assessed the performance of a new heparin-bonded ePTFE vascular graft that was designed to provide resistance to thrombosis and thereby decrease early graft failures and possibly prolong patency. METHOD: From June 2002 to June 2003, 86 patients (62 men and 24 women; mean age, 70 years; 99 diseased limbs) were enrolled prospectively in a nonrandomized, multicenter study of the heparin-bonded ePTFE graft. Fifty-five above-knee and 44 below-knee (including 21 femorocrural) procedures were performed. Follow-up evaluations consisted of clinical examinations, ultrasonographic studies, and distal pulse assessments. Patency and limb salvage rates were assessed by using life-table analyses. RESULTS: All grafts were patent immediately after implantation. There were no graft infections or episodes of prolonged anastomotic bleeding. During the 1-year follow-up, 10 patients died, 15 grafts occluded, and 5 major amputations were performed. The overall primary and secondary 1-year patency rates were 82% and 97%, respectively. The limb salvage rate in patients with critical limb ischemia (n = 41) was 87%. Primary patency rates according to bypass type were 84%, 81%, and 74% for above-knee femoropopliteal, below-knee femoropopliteal, and femorocrural bypasses, respectively; the corresponding secondary patency rates were 96%, 100%, and 100%. CONCLUSIONS: In this study, the heparin-bonded ePTFE graft provided promising early patency and limb salvage results, with no device-related complications, in patients with occlusive vascular disease. Longer-term and randomized studies are warranted to determine whether this graft provides results superior to those achieved with other prostheses, especially in patients at increased risk of early graft failure, such as those undergoing below-knee bypass and those with poor run-off or advanced vascular disease.
OBJECTIVES: The study was conducted to identify patient and procedural parameters that negatively impact the 30-day rates for stroke, death and transient ischemic attack (TIA) after carotid artery stenting (CAS) and that might be modified or further studied in future efforts to improve CAS. METHODS: This was a retrospective investigation of a dual-center CAS database of 701 consecutive CAS patients (414 men; mean age, 72.4 +/- 8.4). A subset of patient-related, lesion-related, or procedure-related variables (age >or=80, left sided lesion, symptomatic, nicotine abuse, hypertension, diabetes mellitus, other peripheral vascular disease, hypercholesterolemia, embolic protection devices usage, predilation, ulcerated lesion, echolucent plaque, restenosis after surgery) were analyzed for association with occurrence of stroke, death, or TIA <or=30 days after CAS. The odds ratio (OR) and 95% confidence interval (CI) and P value were calculated for each variable to predict adverse outcome. RESULTS: The overall combined rate of stroke, death, and TIA within this database was 3.7% at 30 days. In the total population of 701 patients, only the OR of 2.7 for hypercholesterolemia (95% CI, 1.0 to 7.3; P = .041) was found to be significant. Subgroup analysis of the 304 symptomatic patients (43%) showed that open-cell stent designs and concentric EPD designs yielded an OR of 4.1 (95% CI, 1.4 to 12, P = .0136) and 3.3 (95% CI, 1.016 to 10, P = .0525), respectively, for 30-day stroke/death/TIA within this database. Analysis of open-cell stent designs and concentric EPD designs in patients with echolucent lesions yielded an OR of 3.1 (95% CI,1.2 to 8.2, P = .0343) and 3.7 (95% CI, 1.3 to 10, P = .0174), respectively, for 30-day stroke/death/TIA. CONCLUSIONS: We conclude that increased analysis of device design variables may be necessary. Particularly in symptomatic patients or with echolucent lesions, closed-cell design and eccentric filters seem superior. Prospective investigation comparing open-cell vs closed-cell stents and eccentric vs concentric filter devices may be warranted.
There is a wide variability in the utilization of peritoneal dialysis throughout Europe that cannot be explained by differences in medical factors alone. Over the last years, the utilization of peritoneal dialysis has even changed in individual countries. The main factors of this variation are not medical, but rather changes in reimbursement and other financial considerations. The overall structure of the health care in an individual country is to a large extent determining the use of a renal replacement therapy modality.
OBJECTIVES: Neurologic complications during carotid artery stenting (CAS) are most clearly associated with embolization of visible debris. Distal filter devices may provide cerebral protection by capturing clinically significant debris. However, they increase procedural time and expense and have their own set of complications. The current study was undertaken to identify the clinical factors predictive for the presence or absence of visible debris captured by distal filter devices during CAS. METHODS: Patients undergoing CAS with use of a distal filter device (n = 279) were prospectively entered into an investigational carotid registry. Recorded variables were classified as patient-, lesion-, or procedure-related. The filter was assessed for visible debris in each case. The odds ratio (OR) and 95% confidence interval (CI) were determined for each variable to predict visible debris. The ability of each variable to predict the absence of visible debris was assessed by calculating the individual negative predictive value (NPV). RESULTS: Visible debris was present in 169 filters (60.3%). There was an increased risk of visible debris found with several variables (OR, 95% CI): hypertension (2.9, 1.7 to 5.2), hypercholesterolemia (2.3, 1.4 to 3.9), stent diameter >9 mm (16.6, 9.0 to 30.0), and any neurologic event (4.2, 1.5 to 9.9). The NPV failed to exceed 0.80 (80%) for any variable. The NPV of the variables with a significantly elevated OR was as follows: hypertension (0.60), hypercholesterolemia (0.52), stent diameter >9 mm (0.75), and any neurologic event (0.38). CONCLUSIONS: Several clinical variables are associated with the presence of visible debris captured by distal filter devices. The current study failed to identify any variables capable of consistently predicting the absence of visible debris. These findings support the routine rather than the selective use of cerebral protection during CAS.
PURPOSE: To report the preliminary 3-month follow-up of a recently developed absorbable metal stent (AMS) for treatment of infrapopliteal lesions in patients with critical limb ischemia (CLI). METHODS: Between December 2003 and January 2004, 20 patients (10 men; mean age 76 years, range 59-96) with symptomatic critical limb ischemia (CLI) due to high-grade (80% to 100%) infrapopliteal stenoses received 1 or 2 AMS devices for suboptimal angioplasty. Clinical examination and color-flow duplex imaging were performed in all patients at discharge and at 1 and 3 months. RESULTS: Angiographic procedural success was achieved in all 20 patients. One patient died (non-procedure-related) during the periprocedural period. Three months after the procedure, primary clinical patency was 89.5% (17/19). No major or minor amputation was necessary in any of the patients, yielding a limb salvage rate of 100%. The average improvement in Rutherford class was 2.3 at the 3-month assessment. A comparison of postprocedural and 1-month color-flow duplex ultrasound and magnetic resonance images clearly indicated the ongoing absorption process of the AMS. CONCLUSIONS: After 3 months, the primary clinical patency and limb salvage rates suggest a potentially promising performance of these AMS devices in the treatment of below-knee lesions in CLI patients.
PURPOSE OF REVIEW: Delayed graft function is an important determinant of patient and graft survival. A complex of pathologic mechanisms intervenes in the pathophysiology of this outcome. This paper reviews the main processes involved in delayed graft function as they relate to five chronologically related stages: donor tissue quality, brain death and related stress, preservation variables, immune factors, and recipient variables. RECENT FINDINGS: Dialyzed delayed graft function and nondialyzed slow graft function both have a negative impact on graft survival and on the incidence of acute rejection. Expanded-criteria donors, older donors, and non-heart-beating donors are more frequently used. The long-term results of the use of well-selected non-heart-beating donors are surprisingly good. The process of ischemia/reperfusion injury is already initiated in the brain-death donor and continues during preservation of the graft. Graft-infiltrating T cells, heat shock proteins, and heme oxygenase-1 are implicated in the process. Modifications in immunosuppressive therapy and pharmacologic modulations have an effect on delayed graft function. Delayed graft function plays a part in the incidence of acute rejection, impaired graft function, and survival of patients and grafts. SUMMARY: This review discusses the current literature on several recent findings of pathophysiologic mechanisms of, and possible therapeutic interventions in, delayed graft function.
BACKGROUND: In patients with end-stage renal disease (ESRD), treated with haemodialysis, a high overall mortality is observed. A previous study showed that cardiac troponin T (cTnT) is a strong independent predictor of outcome in this population. In this study we investigated possible causes of cTnT increase and its relationship with a marker of oxidative stress. METHODS: In a group of 71 haemodialysis patients (36 male, 35 female, mean age 68.7+/-1.5 years) we determined cTnT and compared its presence with several biochemical parameters and with malondialdehyde (MDA), which is an indicator of oxidative stress. None of the patients suffered an acute coronary event during the observation period. Three measurements of cTnT and MDA were performed with a 2-week interval. Forty-nine patients underwent a transthoracic echocardiography. RESULTS: Twenty-nine patients (or 40.8%) had a positive cTnT determination (defined as cTnT >/=0.10 ng/ml). cTnT positive patients had significantly higher levels of MDA (P=0.0125), C-reactive protein (CRP) (P=0.04) and pre-dialysis urea (P=0.04). Regression analysis showed that both pre-dialysis urea and MDA independently influenced cTnT. No correlation was found with age, dialysis adequacy, post-dialysis urea, total cholesterol, white blood cell count, fibrinogen or any of the echocardiographical parameters. Presence of heart failure, diabetes or use of medication could not discriminate between cTnT positive and cTnT negative patients. MDA levels correlated positively with time on haemodialysis (P=0.0021). Echocardiography showed left ventricular hypertrophy in 88% of the examined patients and impaired wall motion in 35%. Patients with clinical signs of heart failure had a lower ejection fraction and worse wall motion score index. No correlation existed between echocardiographic findings and cTnT or MDA. Survival was independently predicted by cTnT (P=0.0025), MDA (P=0.0007), CRP (P=0.006) and age (P=0.0143). Patients with both cTnT and CRP increase had a survival of <50% at 1 year, compared with 90% in patients with both cTnT and CRP within the normal range and 80% when either CRP or cTnT was increased (chi(2)=12.127; P=0.0023). CONCLUSIONS: This study confirms that the presence of cTnT predicts prognosis in ESRD. The presence of cTnT is linked to oxidative stress, inflammation and uraemia. The absence of specific findings on EKG and echocardiography points towards subclinical myocardial damage caused by endothelial disturbances.
PURPOSE: To evaluate the performance of the FilterWire EX for the capture and removal of debris and prevention of embolic events during endovascular carotid interventions. METHODS: In the period from October 2001 to May 2002, 100 patients (60 men; mean age 72 years, range 48-90), 69 symptomatic with >or=50% internal carotid artery (ICA) stenosis and 31 asymptomatic with >or=70% stenosis were scheduled for carotid stenting with cerebral protection provided by the FilterWire EX system. Satisfactory performance of the filter was defined as effectiveness in preventing intraprocedural embolic events shown by visible debris in the filter and unchanged neurological status assessed by an independent neurologist. RESULTS: The placement and retrieval of the FilterWire EX was technically successful in 93 of 100 patients. Five delivery failures were due to severe ICA angulation; one stenosis was underestimated on preprocedural imaging, and one case was aborted following a major stroke during sheath manipulation before filter introduction. In 56.9% of the protected cases, the filter contained debris. One neurological event occurred 6 hours after the procedure: a transient ischemic attack from which the patient recovered fully after 2 hours. No other procedure-related events were recorded within 30 days of the procedure. The procedural success among the 93 patients stented under FilterWire EX protection was 98% (92% by intention to treat). CONCLUSION: The FilterWire EX appears to be an effective tool in the prevention of embolic events and in preserving neurological status during endovascular treatment of carotid artery stenosis.
Patients presenting with atherosclerosis of the extracranial carotid arteries may be offered carotid endarterectomy (CEA), carotid artery stenting (CAS), or medical therapy to reduce their risk of stroke. In many cases, the choice between treatment modalities remains controversial. An algorithm based on patients' neurologic symptoms, comorbidities, limiting factors for CAS and CEA, and personal preferences was developed to determine the optimal treatment in each case. This algorithm was then employed to determine therapy in 308 consecutive patients presenting to a single institution during one calendar year. Ninety-five (30.8%) patients presented with an asymptomatic carotid stenosis of more than 80% and 213 (69.2%) with a symptomatic stenosis of more than 50%. According to our algorithm, 59 (62.1%) of the 95 asymptomatic patients received CAS, 20 (21.1%) received CEA, and 16 (16.8%) received medical therapy. All symptomatic patients underwent intervention; 153 (71.8%) were treated with CAS and 60 (28.2%) with CEA. Combined 30-day stroke and death rates after CAS were 1.7% in asymptomatic patients and 2.6% in symptomatic patients. After CEA, these rates were 0% and 3.3%, respectively. Careful selection of treatment modality according to predetermined criteria can result in improved outcomes.
The different geometries and working principles of carotid stents (nitinol or cobalt chromium, open- or closed-cell configuration) provide each product with unique functional properties. The individual characteristics of each device may make it an attractive choice in one circumstance but render it less desirable in other situations. In approximately 75% of all procedures, all types of stents will achieve similar outcomes, making adequate device selection unnecessary. For the remaining quarter, careful preoperative screening is mandatory. In addition to eventual access issues, the choice of the optimal carotid stent depends mainly on arterial anatomy and lesion morphology. When treating a tortuous anatomy, stents with a flexible and comformable open-cell configuration are preferred. In arteries with a significant mismatch between common carotid artery and internal carotid artery diameter, cobalt chromium (Elgiloy) or tapered nitinol stents are selected. Lesions with suspected high emboligenicity are best covered with stents with a closed-cell configuration, whereas highly calcified lesions need treatment with nitinol stents. Thorough knowledge of the characteristics, advantages and disadvantages, and working principles of the different available stents is mandatory to optimally select the materials to be used for patients eligible for carotid revascularization.
Endovascular strategies for the treatment of critical infrageniculate peripheral arterial occlusive disease exist and are becoming the primary methodology for such lesions at many centers. Although technically feasible for experienced operators, the evidence to support this strategy for below the knee (BTK) interventions is still evolving. We studied the 6-month and 1-year outcomes of percutaneous transluminal angioplasty (PTA) alone, PTA with stenting, and excimer laser recanalization for BTK lesions in patients with critical limb ischemia. Between September 2002 and June 2005, 443 patients (355 Rutherford category 4, 82 category 5, 6 category 6) underwent intervention for 681 BTK lesions. Follow-up was performed at 6-month intervals after index intervention: limb salvage data were recorded and duplex ultrasonography was performed to measure the patency of treated areas. The primary patency and limb salvage rates of the entire population were 85.2% and 97.0% and 74.2% and 96.6% at 6 months and 1 year, respectively. Stratified for the treatment strategy (PTA alone in 79, PTA with stenting in 300 patients, and excimer laser in 64), 1-year primary patency rates were 68.6%, 75.5%, and 75.4%, whereas the limb salvage rates were 96.7%, 98.6%, and 87.9% for each modality, respectively. Endovascular intervention will become the primary treatment for BTK lesions in patients with critical limb ischemia, with 1-year primary patency and limb salvage rates that compare favorably with published surgical data. Prospective, randomized, multicenter trials will be needed to further establish the role of endovascular intervention in this challenging patient group.