Reduction in Renal Function After Renal Arteriography and After Renal Artery Angioplasty

AbstractObjective: to investigate the incidence and risk factors for renal function deterioration after renal angiography and angioplasty or stenting.Methods: a retrospective study of 85 consecutive patients undergoing selective renal artery arteriography (n=53) or renal artery angioplasty % (PTRA) stenting (n=32) for renal artery stenosis. Multivariate logistic regression analysis was used to determine independent predictors of deterioration of renal function, defined as an increase of serum creatinine by at least one third within 24h.Results: deterioration of renal function occurred in 13 patients (15%), [8/53 (15%) after angiography and 5/32 (16%) after PTRA/stenting]. Only pre-existing renal impairment (se-creatinine≥177μmol/l) (Odds ratio: 40; 95% confidence interval 1.2–72, p=0.02) and administered dosage of contrast agent (more than 225ml) (OR 67; 95% CI1 1.8–100, p=0.02) were independently associated with renal function deterioration.Conclusion: transient renal dysfunction after renal artery angiography or PTRA/stenting occurs in about 15% of patients, but persistent renal failure is uncommon. Pre-existing renal impairment and amount of contrast agent are independent risk factors. Endovascular treatment of renal artery stenosis is not associated with a higher risk of renal deterioration compared to selective renal angiography

Heme oxygenase-1 genotype and restenosis after balloon angioplasty: a novel vascular protective factor

AbstractObjectivesWe investigated the association of the heme oxygenase-1 (HO-1) promoter genotype with the inflammatory response and restenosis after balloon angioplasty.BackgroundHeme oxygenase-1, which is induced by balloon angioplasty, can inhibit neointima formation and vascular remodeling. A dinucleotide repeat in the HO-1 gene promoter shows a length polymorphism that modulates HO-1 gene transcription. Short (<25 guanosine thymidine [GT]) repeats are associated with a 10-fold greater up-regulation of HO-1 than are longer repeats.MethodsWe studied 381 consecutive patients who underwent femoropopliteal balloon angioplasty (n = 210) and comparison groups with femoropopliteal stenting (n = 68) and lower limb angiography (n = 103). C-reactive protein (CRP) was measured at baseline, 24, and 48 h. We evaluated patency at six months by duplex sonography and assessed the association of the length of GT repeats in the HO-1 gene promoter with postintervention CRP and restenosis.ResultsRestenosis within six months was found in 74 patients (35%) after balloon angioplasty and in 21 patients (31%) after stenting. After balloon angioplasty, carriers of the short length (<25 GT) dinucleotide repeats had a lower postintervention CRP at 24 h (p = 0.009) and 48 h (p < 0.001) and a reduced risk for restenosis (adjusted relative risk 0.43, 95% confidence interval: 0.24 to 0.71, p < 0.001) compared with patients with longer alleles. After stenting or angiography, we found no association between the HO-1 genotype with CRP or restenosis.ConclusionsThe HO-1 promoter genotype that controls the degree of HO-1 up-regulation in response to stress stimuli is associated with the postintervention inflammatory response and the restenosis risk after balloon angioplasty

Sustainable injection moulding: The impact of materials selection and gate location on part warpage and injection pressure

This paper presents an approach of how warpage (i.e. part deflection) and injection pressure of an intricate geometry could be minimised by selecting an optimal thermoplastic material and injection gate location (through which the molten plastic flows into the cavity). The numerical analyses for mould filling considered four gate locations along with a PP (polypropylene), PS (polystyrene) and a fibre-filled PP material (each had different shrinkage characteristics, mechanical property and viscosity). Results of the cavity filling simulations indicated that (on average) the largest and smallest warpage was predicted with the PP and PS respectively. The warpage of the fibre-filled PP showed the most gate location dependent behaviour. In addition, the lowest injection pressure was associated with the fibre-filled PP. For reduced pressure, the best and second best solutions for gate location were the top and middle ones. In addition, specific attention was paid to differential fibre orientation, as one of the most important factors responsible for part warpage. In an attempt to maximise the part stiffness, the fibre-filled PP was selected. It became clear that the gate location affected the melt flow evolution and therefore the fibre orientation. Simulation results showed that bidirectional flow and asymmetrical fibre distribution was achieved with the gate positioned at the mid-section of the part. Unidirectional flow and therefore symmetrical fibre distribution could be achieved by placing the gate at the top section of the part. The injection moulding experimental utilised the fibre-filled PP along with the two aforementioned gate locations. It was discovered that warpage was present when the middle gate was applied, but it was successfully eliminated using the top gate location. It can be stated that differential fibre orientation did not cause warpage, but the asymmetrical distribution of fibre orientation did. The information discussed in the paper may be particularly useful in the early mould/part design stages when any modification can still be easily and cost-effectively implemented. An important finding is that the final gate location should only be chosen after the thermoplastic material properties and melt flow direction have been taken into account. The successful reduction of warpage and injection pressure may help to reduce the amount of production waste and energy consumption, ensuring defect-free sustainable manufacturing

Pain inhibition is not affected by exercise-induced pain

Introduction: Offset analgesia (OA) and conditioned pain modulation (CPM) are frequently used paradigms to assess the descending pain modulation system. Recently, it was shown that both paradigms are reduced in chronic pain, but the influence of acute pain has not yet been adequately examined. Objectives: The aim of this study is to investigate OA and CPM after exercise-induced pain to evaluate whether these tests can be influenced by delayed-onset muscle soreness (DOMS) at a local or remote body site. Methods: Forty-two healthy adults were invited to 3 separate examination days: a baseline appointment, the consecutive day, and 7 days later. Participants were randomly divided into a rest (n 5 21) and an exercise group (n 5 21). The latter performed a single intensive exercise for the lower back. Before, immediately after, and on the following examination days, OA and CPM were measured at the forearm and the lower back by blinded assessor. Results: The exercise provoked a moderate pain perception and a mild delayed-onset muscle soreness on the following day. Repeatedmeasurements analysis of variance showed no statistically significantmaineffect for eitherOAorCPMat the forearmor lower back (P.0.05). Conclusion: Delayed-onset muscle soreness was shown to have no effect on the inhibitory pain modulation system neither locally (at the painful body part), nor remotely. Thus, OA and CPM are robust test paradigms that probably require more intense, different, or prolonged pain to be modulated

Pain and Disability in Low Back Pain Can be Reduced Despite No Significant Improvements in Mechanistic Pain Biomarkers

Objective: Altered balance in nociception in response to noxious stimuli is commonly reported in chronic low back pain (LBP). However, it is unclear whether an improvement in the clinical presentation is contingent on a reduction in pain sensitivity. This study investigated whether the quantitative sensory testing (QST) profile changes in people undergoing rehabilitation for LBP. Design: A prospective, observational case-control study. Methods: Forty males and females, 18-40 years' old, (20 with LBP) participated in two sessions. QST was performed at baseline and after discharge from rehabilitation (LBP) or after 3-8 weeks (controls). The QST battery consisted of determining pressure-pain thresholds (PPT) at the low back and shoulder, temporal summation of pain and conditioned pain modulation. Questionnaire data was used to determine pain (Numeric Rating Scale; NRS), disability (Roland-Morris Questionnaire, RMQ), Fear Avoidance Beliefs (FABQ) and The Örebro Musculoskeletal Pain Screening Questionnaire (ÖMPSQ) at baseline and discharge. The treatment effect was determined by calculating the Cohen's d. Results: No significant group x time interactions or main factor effect was found for any of the QST measures. The LBP group reported a significant reduction in NRS (P<0.0002, d=1.23), RMQ (P<0.0001, d=1.58), FABQ (P< 0.001, d=0.87) and in the ÖMPSQ (P<0.00001, d=1.44). Conclusions: The results indicate that an improvement of clinical LBP is not contingent upon changes in the pain sensory profile. The value of screening pain sensitivity in low back pain patients in primary care, needs to be investigated further, due to the patient population heterogeneity and the sensitivity of assessment methods

Neuropsychological Sequelae of Carotid Angioplasty with Stent Placement: Correlation with Ischemic Lesions in Diffusion Weighted Imaging

BACKGROUND AND PURPOSE: Few studies investigated the neuropsychological outcome after carotid angioplasty with stent placement (CAS), yielding partially inconsistent results. The present investigation evaluated the effect of CAS in patients with high-grade stenosis and assessed the predictive value of ischemic lesion number for postinterventional cognitive deterioration. METHODS: 22 patients were tested neuropsychologically before and six weeks after CAS. Cerebral ischemic changes were assessed with diffusion weighted imaging (DWI) prior to and after angioplasty. RESULTS: Pre- to postinterventional cognitive performance improved significantly in terms of verbal memory (t = -2.30; p<0.05), whereas significant deterioration was noted regarding verbal memory span (t = 2.31; p<0.05). 8 (36%) persons conformed to the criteria of cognitive improvement. 6 patients (27%) were postinterventionally classified as having deficits. Analysis yielded no statistically significant correlations between lesion quantity and cognitive change. CONCLUSION: Both improvement and deterioration of cognitive functioning was observed in our collective of patients, leaving the neuropsychological outcome after percutaneous transluminal angioplasty unpredictable in individual cases. The presence of acute ischemic lesions on DWI was found to be not tightly associated with cognitive dysfunction after CAS

Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial: A survival prediction model to facilitate clinical decision making

BackgroundAn intention-to-treat analysis of the Bypass versus Angioplasty in Severe Ischaemia of the Leg (BASIL) trial showed that in patients with severe lower limb ischemia (SLI) due to infrainguinal disease who survived for 2 years after intervention, initial randomization to a bypass surgery (BSX)-first vs balloon angioplasty (BAP)-first revascularization strategy was associated with improvements in subsequent overall survival (OS) and amputation-free survival (AFS) of about 7 and 6 months, respectively. This study explored the value of baseline factors to estimate the likelihood of survival to 2 years for the trial cohort (Cox model) and for individual BASIL trial patients (Weibull model) as an aid to clinical decision making.MethodsOf 452 patients presenting to 27 United Kingdom hospitals, 228 were randomly assigned to a BSX-first and 224 to a BAP-first revascularization strategy. Patients were monitored for at least 3 years. Baseline factors affecting the survival of the entire cohort were examined with a multivariate Cox model. The chances of survival at 1 and 2 years for patients with given baseline characteristics were estimated with a Weibull parametric model.ResultsAt the end of follow-up, 172 patients (38%) were alive without major limb amputation of the trial leg, and 202 (45%) were alive. Baseline factors that were significant in the Cox model were BASIL randomization stratification group, below knee Bollinger angiogram score, body mass index, age, diabetes, creatinine level, and smoking status. Using these factors to define five equally sized groups, we identified patients with 2-year survival rates of 50% to 90%. The factors that contributed to the Weibull predictive model were age, presence of tissue loss, serum creatinine, number of ankle pressure measurements detectable, maximum ankle pressure measured, a history of myocardial infarction or angina, a history of stroke or transient ischemia attack, below knee Bollinger angiogram score, body mass index, and smoking status.ConclusionsPatients in the BASIL trial were at high risk of amputation and death regardless of revascularization strategy. However, baseline factors can be used to stratify those risks. Furthermore, within a parametric Weibull model, certain of these factors can be used to help predict outcomes for individuals. It may thus be possible to define the clinical and anatomic (angiographic) characteristics of SLI patients who are likely—and not likely—to live for >2 years after intervention. Used appropriately in the context of the BASIL trial outcomes, this may aid clinical decision making regarding a BSX- or BAP-first revascularization strategy in SLI patients like those randomized in BASIL