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Biomedical subjects

P J Kent

Publications and source records attributed to P J Kent.

At least 19 recordsLinked to original sources
PubMed2006

The PADHOC device is a better guide to the actual incapacity suffered by claudicants than the gold standard constant load treadmill test.

BACKGROUND: The Constant Load Treadmill Test (CLTT) is currently the primary method used to measure walking impairment in patients with peripheral vascular disease. The aim of this study was to compare the CLTT and PADHOC device as assessments of walking impairment. METHODS: 55 patients with intermittent claudication underwent a CLTT and a Double Physiological Walking Test (DPWT) using the PADHOC device. Health-related quality of life was measured using the Short Form 36 and the Claudication Scale. RESULTS: The initial claudication and maximum walking distance from the first part of the DPWT showed the best correlation with domains of pain and physical function. CONCLUSIONS: The DPWT is more representative of the functional incapacity experienced by patients with intermittent claudication. We believe that the PADHOC is a suitable alternative to the CLTT in the assessment of this patient group.

Aged↗
PubMed2005

Intra-operative Doppler flow measurement do not predict 'at-risk' status of infrainguinal bypass grafts.

AIMS: Patients undergoing infrainguinal arterial reconstruction using vein conduits, frequently undergo intra-operative Doppler flow measurements to determine technical adequacy. The aim of this study was to determine the proportion of vein grafts with normal intra-operative haemodynamic parameters that were subsequently discovered to be 'at risk' on post-operative duplex surveillance scanning. METHODS: We prospectively collected data on 82, primary infrainguinal vein bypass grafts. Post papaverine graft flow and peripheral resistance were measured using the Scimed Opdop intra-operative Doppler machine. All grafts were determined to be technically adequate on the basis of measured peripheral resistance units (mPRU) being < or =1. At 1 week, a post-operative duplex surveillance scan was performed. At risk status was determined and compared to the intra-operative Doppler flow measurement. Statistical analysis was performed using the Mann-Whitney U-test. RESULTS: The post-operative duplex scan demonstrated that 53 (65%) of the 82 vein bypass grafts were diagnosed as being 'not at risk'; and 29 (35%) were regarded as at risk. When the groups were compared, there was no significant difference in intra-operative haemodynamic parameters between those not at risk and those at risk (P=0.19, Mann-Whitney U-test). The 1 month primary patency rate was 79% with a secondary patency rate of 100%. CONCLUSION: Despite normal intra-operative Doppler flow measurements, 35% of vein grafts were regarded as being at risk at the 1 week post-operative duplex surveillance scan. No single value may be universally applicable for identifying at risk grafts intraoperatively. Indeed, graft failure appears to be a multifactorial process.

Aged↗
PubMed2004

Randomized clinical trial of intraoperative autotransfusion in surgery for abdominal aortic aneurysm.

BACKGROUND: Perioperative homologous blood transfusion (HBT) is associated with adverse reactions and risks transmission of infection. It has also been implicated as an immunosuppressive agent. Intraoperative autotransfusion (IAT) is a potential method of autologous transfusion. METHODS: This was a single-centre randomized clinical trial of IAT in surgery for abdominal aortic aneurysm. Forty patients were randomized to IAT and 41 underwent surgery with HBT only. Patients in both groups received HBT to maintain haemoglobin levels above 8 g/dl. Transfusion requirements, and incidence of systemic inflammatory response syndrome (SIRS) and infection, were compared. RESULTS: Significantly fewer patients in the IAT group required HBT (21 versus 31; P = 0.038) and the median blood requirement per patient was 2 units lower (P = 0.012). There was a higher incidence of chest infection (12 versus four patients; P = 0.049) and SIRS (20 versus nine patients; P = 0.020) in the HBT group. Risk of SIRS was related to aortic cross-clamp time in the IAT group only. CONCLUSION: Use of autotransfusion effectively reduced the need for HBT and was associated with a reduced incidence of postoperative SIRS and infective complications.

Aged↗
PubMed2003

An audit of out of hours interventional vascular radiology.

BACKGROUND: in 1996 the Royal College of Radiologists established a set of guidelines for out of hours radiology. Part of the recommendations determined that all units should regularly assess their own out of hours workload. In light of these guidelines we have audited our units interventional radiology activity. METHODS: this was a retrospective study looking at the number of emergency angiograms and procedures performed over a 1-year period. Patients were identified from a vascular radiology database and case notes reviewed. RESULTS: a total of 1902 patients had angiograms with 686 having further procedures. Of these, 1093 patients (57%) having 380 procedures (55%) were under the care of a consultant vascular surgeon. Of the vascular surgical patients only 17 patients (1.6%) were actually investigated out of hours (1700-0800 weekdays and at weekends). 5/17 (29%) patients received thrombolysis and 7/17 (41%) had either an angioplasty or stent. Despite being a major vascular unit only 2/17 (12%) were patients referred from outside the units own trust. Following diagnostic angiography, 13/17 (76%) of patients had an intervention performed within the first 24h. CONCLUSION: in a unit performing a large number of angiograms only a small number of patients require out of hours emergency angiography and interventional vascular procedures. Our impression is that this is the result of a flexible and responsive in hour's service. At the present time extra-hospital referrals do not appear to generate large amounts of out of hours work. This level of out of hours activity has implications in the provision of vascular radiological services in the future.

Adult↗
PubMed2002

Femorofemoral venous bypass graft for the treatment of venous occlusion of the common femoral vein in a nine year old boy.

Unlike arterial disease, most vascular surgeons have very little experience in performing bypass procedures for venous obstruction especially when occurring in children. Given the lack of published literature when compared to arterial procedures, we report a successful venous crossover procedure following iatrogenic injury and subsequent occlusion of the right common femoral vein in a nine year old boy.

Arteriovenous Shunt, Surgical↗
PubMed2001

A new device for the measurement of disease severity in patients with intermittent claudication.

OBJECTIVES: To assess a new method of determining functional impairment in patients with intermittent claudication, the Double Physiological Walking Test (DPWT) using the PADHOC (Peripheral Arterial Disease Holter Control) device, against a standard treadmill test. DESIGN: Patients with intermittent claudication presenting to the department were considered for both the DPWT and a standard treadmill test. METHODS: initial claudicating distance, maximal walking distance and speed of walking were determined for both parts of the DPWT. Initial claudicating distance and maximal walking distance were determined from the treadmill test. Comparisons were made between the treadmill test and the DPWT. RESULTS: The treadmill test was unable to be performed in 22% of patients due to defined contraindications. There were strong correlations in both walking distances and disease severity when comparing the DPWT and the treadmill test. Patients in whom the treadmill test was contraindicated had significantly shorter walking distances on the DPWT than those who were able to complete a treadmill walking test. CONCLUSIONS: The DPWT correlates strongly with walking distances obtained from a standard treadmill test. However, the PADHOC can be used in a number of differing locations and settings as well as in patients in whom a treadmill test is contraindicated. It therefore has a role to play in the initial assessment of patients presenting with intermittent claudication.

Aged↗
PubMed2001

The analysis of sensitivity, specificity, positive predictive value and negative predictive value of cold provocation thermography in the objective diagnosis of the hand-arm vibration syndrome.

The diagnosis of digital artery vasospasm in the hand-arm vibration syndrome (HAVS) is clinically based, and the need for an accurate objective test to support the diagnosis has been highlighted. This study aims to analyse the potential of cold provocation thermography (CPT) to fulfill this role. CPT was performed on two groups of subjects: 10 controls and 21 patients with Raynaud's phenomenon (RP) secondary to HAVS. After taking a pre-cooling image, patients donned latex gloves and immersed their hands in water at a temperature of 5 degrees C for 1 min. The patients removed their hands from the water and discarded the gloves, and further images were taken every 30 s for 10 min. On each image, the temperatures of the tip and base were analysed for each digit. The sensitivity, specificity, positive and negative predictive values for fingertip temperatures only, fingertip and fingerbase temperatures combined, and fingertip temperature, fingerbase temperature and temperature gradient combined were determined. Patients with RP secondary to HAVS demonstrated significantly lower finger tip and base temperatures and lower digital temperature gradients at all time intervals when compared with controls (P < 0.01, Student's t-test). CPT has good sensitivity, specificity, positive predictive value and negative predictive value; it strongly supports the clinical diagnosis of digital vasospasm.

Adult↗
PubMed2001

A comparison between two methods of aesthesiometric assessment in patients with hand-arm vibration syndrome.

Hand-arm vibration syndrome (HAVS) is caused by prolonged exposure to vibration. The diagnosis and assessment of disease severity are subjective at present. The aim of this study was to determine sensorineural dysfunction in patients with HAVS using two methods of aesthesiometric assessment. We recruited three groups of age-matched subjects: 20 subjects diagnosed as having HAVS, 15 manual workers and 15 sedentary workers. We measured both two-point discrimination and depth sense perception using an aesthesiometer. We found that the two-point discrimination wheel was more accurate than the depth sense perception wheel at detecting levels of sensorineural dysfunction in subjects with HAVS. The increased sensitivity of the two-point disc would suggest that it should be used in preference to the depth sense disc for the assessment of sensorineural dysfunction in patients with HAVS.

Adult↗
PubMed2001

Cyclist's iliac syndrome: temporary relief by balloon angioplasty.

External iliac stenosis due to endofibrosis is a rare condition that predominantly affects top level cyclists. Short term symptomatic relief is reported in an Olympian after percutaneous transluminal angioplasty, which was performed to allow the patient to return to training without delay.

Adult↗
PubMed2000

Clinical examination of varicose veins--a validation study.

The aim of this study was to determine the accuracy of clinical tests compared to colour duplex imaging in patients with primary varicose veins using a prospective, blinded comparison study. A total of 44 patients (70 limbs) with primary, previously untreated varicose veins presenting to the vascular laboratory of a university teaching hospital were studied. The patients underwent physical examination using the cough test, the tap test, Trendelenbergs' test, Perthes' test and hand-held Doppler (HHD) assessment prior to undergoing colour duplex scanning. Reflux was detected on duplex scanning, at the sapheno-femoral junction in 39/70 limbs (54%), the long saphenous vein in 47/70 limbs (64%) and the sapheno-popliteal junction in 9/70 limbs (13%). The cough test had low sensitivity (0.59) and specificity (0.67). The tap test had low sensitivity (0.18) and high specificity (0.92). The Trendelenberg test had high sensitivity (0.91) but low specificity (0.15). Perthes' test had a high sensitivity (0.97) but low specificity (0.20). Hand-held Doppler assessment of reflux at the sapheno-femoral junction, in the long saphenous vein and at the sapheno-popliteal junction had high sensitivity (0.97, 0.82, and 0.80, respectively) and specificity (0.73, 0.92, and 0.90, respectively) of detecting reflux. Clinical tests used in the examination of patients with primary varicose veins are inaccurate. Assessment using hand-held Doppler is more accurate. Courses and clinical textbooks should be revised to replace these tests with instruction in how to use hand-held Doppler in the clinical examination of patients with varicose veins.

Adolescent↗
PubMed1999

Duplex-derived evidence of reflux after varicose vein surgery: neoreflux or neovascularisation?

BACKGROUND: Recurrent varicose veins remain a problem in surgical practice despite improvements to the preoperative investigation of, and surgery for varicose veins. Neovascularisation accounts for some cases of recurrence within a few years of surgery, but other factors relating to disease progression must also play a part. We investigated whether new venous reflux (neoreflux) could occur in the early postoperative period (within 6 weeks) following successful varicose vein surgery. METHODS: Eighteen-month prospective observational study in the dedicated vascular surgery unit of a university teaching hospital. Forty-six patients, with primary saphenofemoral junction reflux, awaiting varicose vein surgery were chosen consecutively from the waiting list. All saphenofemoral surgery was performed in a standardised fashion. Assessments were performed prior to, at 6 weeks and at 1 year after surgery. Duplex ultrasound was used to identify and locate sites of reflux. RESULTS: Neoreflux was present at the 6-week postoperative scan in nine limbs after varicose vein surgery (19.6%), and resolved in 55.6% of patients within 1 year. Neovascularisation was noted in two limbs at the 1-year scan. CONCLUSION: New sites of reflux, which may resolve spontaneously, occur in the early postoperative period despite adequate varicose vein surgery. It is our hypothesis that this is a manifestation of the effect of altered venous haemodynamics in a system of susceptible veins.

Adult↗
PubMed1998

The hand arm vibration syndrome: a review.

Since its first description over eight decades ago, the hand arm vibration syndrome-- vibration white finger as it was previously known--has become one of the most common prescribed diseases in the industrialized world. This article is intended to provide a broad review of existing evidence and knowledge regarding a disease which, for medicolegal reasons, demands attention from all medical personnel. Detailed discussion is presented regarding: the multifactorial aetiology of the syndrome; suggestions for clinical assessment, laboratory investigations and classification of disease severity; and strategies for the prevention and treatment of the syndrome.

Fingers↗
PubMed1998

The aetiology of Raynaud's phenomenon.

The literature on Raynaud's phenomenon (RP) describes a complex and confusing picture of abnormalities that has suggested a multifactorial aetiology. Current research suggests that the underlying disorder is related to a local fault at the level of the digital microcirculation. It is likely that many of the biological changes described in RP are secondary manifestations of this primary abnormality. The strong familial relationship of RP suggests a genetic link although this has not yet been characterized. An overactivity of the sympathetic nervous system appears less likely as a candidate for the primary abnormality and dysfunction at the level of the nerve, and vessel wall may be more important. Digital cutaneous neurones show a deficient release of the vasodilatory calcitonin gene related peptide in PR. This may represent a primary fault that is confounded by other factors, which are influenced by cold or emotional triggers. Vasoconstricting substances such as catecholamines, endothelin-1 and 5-hydroxytryptamine, which may all be released in response to cold exposure, could cause digital artery closure and the associated symptoms of RP. In some cases, this would trigger a cascade of neutrophil and platelet activation, which through the release of inflammatory mediators, contribute to the endothelial damage seen with more severe RP. It is hypothesised that disturbance to the intricate functioning of the endothelium, and secondary compensation at local or systemic level, may appear over time. There is, therefore, still a need to differentiate the true aetiological factors from those that are causal associations with Raynaud's phenomenon. Progress is slowly being made with better understanding of the intricacies between these factors and the microcirculation. Deepening our comprehension of the 'normal' mechanisms that influence microvascular blood flow is necessary to develop a better understanding of the pathophysiology of Raynaud's phenomenon.

Blood Platelets↗
PubMed1998

Exercise-induced neutrophil activation in claudicants: a physiological or pathological response to exhaustive exercise?

OBJECTIVES: To assess the effect of exhaustive exercise on neutrophil activation and degranulation in claudicants and controls. We investigated the hypothesis that neutrophil activation and degranulation are normal responses to exhaustive exercise in healthy patients. DESIGN: This was a controlled experimental two-group study. MATERIALS: Exercise was performed using a fixed workload treadmill test. Neutrophil activation was assessed by flow cytometry of whole blood labelled with anti-CD11b mouse IgG, and neutrophil degranulation in terms of plasma elastase measured by enzyme-linked immunosorbent assay. METHODS: Twenty-eight claudicants with stage 1 chronic leg ischaemia, and 22 healthy controls were recruited. Blood and urine samples were collected before and after treadmill exercise. Claudicants exercised to their maximum walking distance, and controls at a higher "fatigue" workload for a maximum of 20 min. RESULTS: Exercise produced a brief but significant neutrophilia in both groups. Neutrophil CD11b expression increased significantly after exercise only in the claudicants, and was associated with a significant rise in plasma neutrophil elastase. These indices remained unchanged in the control group at all time points despite exercise at a fatigue level. CONCLUSION: The inflammatory response associated with exercise in claudicants is not simply a physiological response to exhaustive exercise.

Aged↗
PubMed1998

Percutaneous transluminal angioplasty for intermittent claudication: evidence on which to base the medicine.

OBJECTIVES: This study aims to assess the impact of PTA on the quality of life (QoL) of claudicants and to analyse which patients and which arterial lesions derive the most benefit. DESIGN: A prospective observational study. MATERIALS: One hundred and seventeen claudicants undergoing PTA were studied; 35 patients had bilateral disease, whilst 82 had unilateral disease and underwent PTA to a solitary iliac lesion, solitary superficial femoral or a iliac lesion above a diseased superficial femoral artery in 24, 39 and 19 cases, respectively. METHODS: Patients completed the Short Form 36 (SF36) and EuroQol (EQ) QoL assessment instruments prior to and at 1, 3, 6, and 12 months following intervention. The SF36 produces a QoL profile, whilst the EQ produces two QoL indices. RESULTS: Claudication has a deleterious effect on QoL, especially in patients with multi-segment disease. PTA results in an immediate and lasting improvement in the QoL of claudicants. Unilateral claudicants undergoing PTA to a solitary iliac lesion demonstrate the most marked QoL benefits and 12 months post PTA report a QoL approaching that of an age-matched population. Patients with bilateral claudication undergoing unilateral PTA and unilateral claudicants undergoing PTA to a solitary SFA lesion demonstrate some QoL benefits, but at 12 months post PTA do not approach the QoL scores of an age-matched population. Unilateral claudicants undergoing iliac PTA above a diseased SFA demonstrate minimal QoL changes. CONCLUSIONS: These results should influence decision making in the management of claudication and it may be possible to prioritise PTA waiting lists to ensure patients with greatest potential benefit are treated with most urgency.

Adult↗
PubMed1998

Comparison of POSSUM and the Portsmouth predictor equation for predicting death following vascular surgery.

BACKGROUND: The Physiological and Operative Severity Score for enUmeration of Mortality and morbidity (POSSUM) scoring system has been proposed as an accurate predictor of death which takes account of case mix. It appears to overpredict death, and may have drawbacks which prevent accurate individual or subgroup analysis. An alternative system, the Portsmouth predictor equation for mortality (P-POSSUM) may have overcome these problems, but its apparent advantage could be related to inappropriate analysis of POSSUM predictions. METHODS: Some 312 patients having arterial procedures were studied. POSSUM and P-POSSUM scores were used to predict death and compared with actual outcomes. The observed:predicted (O:E) mortality ratios were calculated by two methods for each of the scoring systems. First the analysis devised by the inventors of POSSUM was used and second the method devised for P-POSSUM. RESULTS: The O:E ratio for POSSUM using its recommended 'exponential' method of analysis was 1.14, but it was 0.59 if the P-POSSUM 'linear' analysis was used. The O:E ratio for P-POSSUM using its correct method of analysis was 0.89, but it was 0.67 if the method of analysis devised for POSSUM was used. CONCLUSION: The O:E ratios for POSSUM and P-POSSUM were close to unity when the appropriate analysis was performed. Both POSSUM and P-POSSUM overpredicted death if the incorrect analysis was used.

Aged↗