Opera Occulta

With a mixture of pride and humility I began to turn the pages of the great leather-backed volumes which enclose the early Dissertations of the Royal Medical Society. It was something to be done with care, for the pages are brittle and cachetic. The regular, flowing, almost copper-plate writing is only s lightly faded and is eminently legible. We, who can achieve immaculate script only through the medium of machinery, might pause and consider the scholarship of our predecessors who wrote Greek, Latin or English with artists’ hands

A Prospective Study of Internal Carotid Artery Plication During Carotid Endarterectomy: Early Clinical and Duplex Outcome

AbstractObjective: internal carotid artery (ICA) plication prevents kinking and secures the distal intimal step following carotid endarterectomy (CEA). The aims of this prospective study were to quantify the proportion of patients in whom plication might be beneficial and determine whether plication is associated with an increased incidence of early restenosis and a reduction in postoperative thromboembolic complications. Methods: analysis of a prospectively gathered computerised database. Results: between 1 November 1992 and 31 December 1997, 228 consecutive CEAs were performed in 213 patients, of which 84 (37%) in 79 patients were plicated. Sixty endarterectomy sites have been examined by duplex ultrasonography at a median of 5 (range 1–44) months postoperatively. No abnormality was detected in 52 (87%), six (10%) had restenosis of <50% and two (3%) restenosis of 50–75%. All were asymptomatic. Three patients (3.6%), one of whom died, had an intraoperative neurological event and one patient (1.2%) had a postoperative cerebral haemorrhage. No patient suffered ICA thromboembolism. During the same time period 144 non-plicated CEAs were performed in 134 patients. Of these, one (0.7%) had an intraoperative and five (3.5%) had a postoperative neurological event. Five of these six complications were due to ICA thromboembolism. There was no mortality in the non-plicated group. Conclusion: ICA plication can be used to prevent kinking, secure the distal intimal step, has not, to date, been associated with increased early restenosis rate and has avoided postoperative ICA thromboembolism

The Use of Controls in the Assessment of Clinical Evidence

The prize-winning essay from the B.M.A. Essay Competition for Provisionally Registered General Practitioners. 1961. The essay is abridged.The incorporation of standards or controls into clinical experimentation has become, over the past decade, a widely accepted practice. So much so that there is a danger that the medical profession in general may become uncritical of the practical and, more important, the ethical problems involved. The subject should be under constant review.Are controls really necessary? How best can they be employed? How is the resulting evidence to be assessed? Under what circumstances can the use of controls be justified on ethical grounds

Most incompetent calf perforating veins are found in association with superficial venous reflux

AbstractPurpose: The indications for surgical perforator interruption remain undefined. Previous work has demonstrated an association between clinical status and the number of incompetent perforating veins (IPVs). Other studies have demonstrated that correction of IPV physiology results from abolition of saphenous system reflux. The purpose of this study was to identify which, if any, patterns of venous reflux and obstruction are particularly associated with IPV. Patients and Methods: Two hundred thirty patients and subjects (103 men, 127 women, 308 limbs) with varying grades of venous disease were examined both clinically and with duplex ultrasound scan. The odds ratios (ORs) for the presence of IPVs were calculated for different anatomical distributions of main-stem venous reflux and obstruction. The base group are those with no main-stem venous disease. Results: There were no significant associations between the proportions of limbs demonstrating IPVs and patient age or sex. The ORs for the presence of IPVs in association with other venous disease are as follows (age/sex adjusted): long saphenous vein reflux, OR = 1.86, range = 1.32-2.63; short saphenous vein reflux, OR = 1.36, range = 1.02-1.82; deep system venous reflux, OR = 1.61, range = 1.2-2.15; superficial system reflux, OR = 3.17, range = 1.87-5.4; and deep system obstruction, OR = 1.09, range = 0.51-2.33. The ORs for combinations of venous disorders were calculated. Combinations of disease produced higher odds for the presence of IPVs than those above, the highest being long saphenous vein, short saphenous vein, and deep reflux combined, OR = 6.85 (95% CI, 2.97-15.83; P =.0001). Conclusions: Although the presence of IPVs is associated with venous ulceration, the highest ORs for the presence of IPVs were found in patients with superficial disease alone or in combination with deep reflux. Many of these may be corrected by saphenous surgery alone. (J Vasc Surg 2001;34:774-8.

Chronic venous insufficiency: Clinical and duplex correlations. The Edinburgh Vein Study of venous disorders in the general population

AbstractObjective: The objective of this study was to determine the prevalence of chronic venous insufficiency (CVI) in the general population and to correlate its clinical features with sonographically proven venous reflux. Design of Study: The study design was a cross-sectional survey of the general population. Subjects and Method: Ambulatory men and women, aged 18-64 years, were selected randomly from 12 general practices. Subjects were examined for CVI. Eight segments of the deep and superficial veins were assessed for reflux by means of duplex scanning. Results: A total of 1566 subjects were screened (867 women, mean age 44.8 years; 699 men, mean age 45.8 years) of whom 124 were diagnosed as having CVI: 95, grade 1; 19, grade 2; and 10, grade 3. The age-adjusted prevalence for the whole population was 9.4% in men and 6.6% in women. Prevalence of CVI correlated closely with age and sex, being 21.2% in men >50 years and 12.0% in women >50 years. Heaviness and tension, and a feeling of swelling, aching, and itching, were significantly associated with worsening grade of CVI. CVI was significantly associated with reflux in all deep and superficial segments. The frequency of reflux in both superficial and deep segments increased with the clinical severity of disease. In 30.8% of subjects with CVI in the left leg, reflux was limited to the superficial system. Conclusions: The prevalence of CVI rises steeply with age. There is a strong correlation between venous symptoms and the presence and severity of CVI. CVI is associated in approximately one third of the subjects with incompetence limited to the superficial system and in these a good therapeutic outcome could be expected from surgery to the superficial veins. The severity of clinical features, including Basle CVI grade 1, correlates significantly with prevalence of valvular reflux in the deep and superficial systems. If leg ulcers are to be prevented by timely intervention, a better understanding of the natural history of the association between presenting features and disordered hemodynamics is required. (J Vasc Surg 2002;36:520-5.

The relationship between aortic wall distensibility and rupture of infrarenal abdominal aortic aneurysm

AbstractObjective: A more accurate means of prediction of abdominal aortic aneurysm (AAA) rupture would improve the clinical and cost effectiveness of prophylactic repair. The purpose of this study was to determine whether AAA wall distensibility can be used to predict time to rupture independently of other recognized risk factors. Methods: A prospective, six-center study of 210 patients with AAA in whom blood pressure (BP), maximum AAA diameter (Dmax), and AAA distensibility (pressure strain elastic modulus [Ep] and stiffness [β]) were measured at 6 months with an ultrasound scan-based echo-tracking technique. A stepwise, time-dependent, Cox proportional hazards model was used to determine the effect on time to rupture of age, gender, BP, Dmax, BP, Ep, β, and change in Dmax, Ep, and β adjusted for time between follow-up visits. Results: Median (interquartile range) AAA diameter was 48 mm (41 to 54 mm), median age was 72 years (68 to 77 years), and median follow-up period was 19 months (9 to 30 months). In the Cox model, female gender (hazards ratio [HR], 2.78; 95% CI, 1.23 to 6.28; P =.014), larger Dmax (HR, 1.36 for 10% increase in Dmax; 95% CI, 1.12 to 1.66; P =.002), higher diastolic BP (HR, 1.13 for 10% increase in BP; 95% CI, 1.13 to 1.92; P =.004), and a decrease in Ep (increase in distensibility) over time (HR, 1.38 for 10% decrease in Ep over 6 months; 95% CI, 1.08 to 1.78; P =.010) significantly reduced the time to rupture (had a shorter time to rupture). Conclusion: Women have a shorter time to AAA rupture. The measurement of AAA distensibility, diastolic BP, and diameter may provide a more accurate assessment of rupture risk than diameter alone. (J Vasc Surg 2003;37:112-7.

The virtual flow cytometer: A new learning experience and environment for undergraduate teaching

BackgroundThe use of simulations has been steadily rising in popularity in the biosciences, not only due to the COVID-19 pandemic restricting access to physical labs and equipment but also in the face of rising student numbers. In this study, we describe the development and implementation of a novel, open-access interactive simulation used to not only supplement a laboratory class but to enhance the student learning experience. The simulation provides students with the opportunity to interact with a virtual flow cytometer, design a simple experiment and then critically analyse and interpret raw experimental data.ResultsResults showed that this highly authentic assessment used a much broader range of the mark scheme acting as an excellent discriminatory for student ability compared to simple recall as assessed by multiple-choice questions. Overall, the student response to the new assessment was positive, highlighting the novelty of the assessment, however, some students did experience technical issues when the simulation was used for the first time.ConclusionSimulations can play a crucial role in the student learning cycle by providing a rich, engaging learning environment, however, they need to be used to supplement other hands-on experiences to ensure that students acquire the necessary kinematic skills expected of a successful science graduate

The relationship between aortic wall distensibility and rupture of infrarenal abdominal aortic aneurysm

AbstractObjective: A more accurate means of prediction of abdominal aortic aneurysm (AAA) rupture would improve the clinical and cost effectiveness of prophylactic repair. The purpose of this study was to determine whether AAA wall distensibility can be used to predict time to rupture independently of other recognized risk factors. Methods: A prospective, six-center study of 210 patients with AAA in whom blood pressure (BP), maximum AAA diameter (Dmax), and AAA distensibility (pressure strain elastic modulus [Ep] and stiffness [β]) were measured at 6 months with an ultrasound scan-based echo-tracking technique. A stepwise, time-dependent, Cox proportional hazards model was used to determine the effect on time to rupture of age, gender, BP, Dmax, BP, Ep, β, and change in Dmax, Ep, and β adjusted for time between follow-up visits. Results: Median (interquartile range) AAA diameter was 48 mm (41 to 54 mm), median age was 72 years (68 to 77 years), and median follow-up period was 19 months (9 to 30 months). In the Cox model, female gender (hazards ratio [HR], 2.78; 95% CI, 1.23 to 6.28; P =.014), larger Dmax (HR, 1.36 for 10% increase in Dmax; 95% CI, 1.12 to 1.66; P =.002), higher diastolic BP (HR, 1.13 for 10% increase in BP; 95% CI, 1.13 to 1.92; P =.004), and a decrease in Ep (increase in distensibility) over time (HR, 1.38 for 10% decrease in Ep over 6 months; 95% CI, 1.08 to 1.78; P =.010) significantly reduced the time to rupture (had a shorter time to rupture). Conclusion: Women have a shorter time to AAA rupture. The measurement of AAA distensibility, diastolic BP, and diameter may provide a more accurate assessment of rupture risk than diameter alone. (J Vasc Surg 2003;37:112-7.