Biomedical subjects
Mark Jackson
Publications and source records attributed to Mark Jackson.
Subclavian flap repair: review of 399 patients at median follow-up of fourteen years.
BACKGROUND: Conflicting results have been obtained for the same operation for repair of coarctation of the aorta by different institutes. The purpose of this study was to assess the results of subclavian flap aortoplasty (SFA) alone, performed on 399 patients in a single institute between 1966 and 1995. METHODS: Data were collected retrospectively from the congenital cardiac surgical database at the institute. RESULTS: The median age at operation was 22 days (3 days-49 months). One hundred thirty-four patients had isolated coarctation while 265 children had complex coarctation. Maximum follow-up was 24 years (median, 14 years). Overall mortality over the whole duration of follow-up was 24.8%. Mortality for isolated coarctation at first intervention was 7.4% (operative mortality, 2.6%) while it was 12.8% for complex coarctation. At second intervention the mortality for isolated coarctation was 5%. For the second, third, and fourth interventions the mortality for complex coarctation was 25%, 25%, and 27%, respectively. The survival for isolated coarctation at 1, 5, 10, and 20 years was 94%, 93.2%, 92.4%, and 88.4%, respectively, while it was 74.6%, 66.3%, 63%, and 61.4%, respectively, for complex coarctation. Of the total patients, 15.3% had interventions for recoarctation. The incidence of recoarctation was 13.6% on those patients operated on in the first month of life, while it was 3.6% in older children. A percentage of 3.3% of patients continue to be hypertensive and require medication. There was a significant difference between the systolic blood pressure and anthropometric measurements between the arms. Despite this none of the patients complained of effect on lifestyle. CONCLUSIONS: Despite improved early results the long-term mortality for coarctation remains high. Mortality is higher for complex coarctation as compared with isolated procedures. The incidence of recoarctation after SFA at long term is acceptable and is higher in patients operated on in the first month of life. The overall incidence of hypertension is quite low. Patients remained normotensive when operated upon at the age of 0.9 months. The SFA, no doubt, effects the limb development; however it does not cause limitation in the lifestyle.
Intrapleural instillation of autologous blood in the treatment of prolonged air leak after lobectomy: a prospective randomized controlled trial.
BACKGROUND: The aim of this study was to assess the value of instilling autologous blood into the pleural cavity to seal prolonged air leaks after lobectomy. METHODS: Of 319 lobectomies performed over an 18-month period, 22 patients (6.9%) experienced prolonged air leak (more than 5 days after surgery). Twenty patients consented to be randomly assigned to one of two treatment pathways. The study group received instillation of 120 mL autologous blood into their apical chest drain on the fifth postoperative day, and again if the air leak persisted on days 7 and 9 respectively. No anticoagulation was used for this blood. The control group continued to be treated by tube thoracostomy alone, but if the air leak was still present on the 10th postoperative day they "crossed over" and underwent intrapleural installation of blood as in the study group. RESULTS: After instillation of blood, the air leak was sealed by the next day in 58.6% of treatments. The median length of air leak was 5 days in the study group and 11 days in the control group (p < 0.001). Time to chest drain removal (median 6.5 days versus 12 days) and hospital discharge (median 8 days versus 13.5 days) were both significantly (p < 0.001) shorter in the study group. CONCLUSIONS: This technique is effective in sealing air leaks after lobectomy. It allows earlier chest drain removal and shortens hospital stay.
Medical Education past, present and future.
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Pharmacy management methods in Canada, including lower-cost therapy for heartburn.
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Circumstances and mode of in-hospital death in 5750 consecutive patients undergoing percutaneous transluminal coronary angioplasty.
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Exercise duration and peak systolic blood pressure are predictive of mortality in ambulatory patients with mild-moderate chronic heart failure.
BACKGROUND AND AIMS: It is a prevailing concept in chronic heart failure (CHF) that ventricular remodelling (evaluated via imaging) and neurohormonal activation (via biomarkers) exert major influences, such that the need to subject patients to haemodynamic evaluations and exercise testing has been questioned. We sought to investigate whether exercise and haemodynamic parameters lack independent prognostic value in a cohort of unselected ambulatory patients with mild-moderate CHF. METHODS: Eighty-five consecutive patients with stable CHF in New York Heart Association functional classes I-IV, aged 55 +/- 12 years, 84% males, left ventricular ejection fraction (LVEF) 37 +/- 15%, participated in this study. Survivors were followed for a median of 5.08 years. All subjects underwent cardiopulmonary exercise testing to measure standard parameters including peak oxygen consumption, exercise duration and blood pressure. A sample of venous blood was taken to determine the N-terminal pro-brain natriuretic peptide (N-BNP) level. Echocardiography was performed at rest to measure LVEF. Predictors of mortality were sought using the Cox proportional hazards model. RESULTS: All-cause mortality was 19% (16 deaths, 95% CI 11-29%). Age and LVEF did not independently predict mortality. Although various parameters including New York Heart Association class, peak oxygen consumption and N-BNP level were all predictive of outcome on univariate analysis, multivariate analysis identified reduced exercise duration and peak systolic blood pressure (SBP) to be the only independent predictors of all-cause mortality. Hazard ratios of 0.78 (95% CI 0.65-0.93, p = 0.007) and 0.79 (95% CI 0.66-0.95, p = 0.01) were associated with an increase in exercise duration of 1 min and 10 mm Hg peak SBP, respectively. CONCLUSIONS: Two simple parameters (exercise duration and peak SBP) that are easily measured by standard exercise testing are the strongest independent predictors of mortality which outperform LVEF and N-BNP in ambulatory patients with mild-moderate CHF.
Does treatment with ACE inhibitors or angiotensin II receptor antagonists prevent atrial fibrillation after dual chamber pacemaker implantation?
AIMS: A retrospective observational study was performed to test the hypothesis that a lower incidence of atrial fibrillation (AF) would be observed in patients treated with either angiotensin converting enzyme (ACE) inhibitors or angiotensin II receptor antagonists (AIIRAs) than those without these drugs, 1-year following implantation of a dual chamber pacemaker for all indications. METHODS: One hundred and sixty consecutive patients who underwent implantation of a dual chamber pacemaker between January and August 2002 were identified and their case notes were retrospectively analysed. The primary endpoint was the presence of persistent AF (confirmed by 12-lead ECG recorded from the visit to the pacemaker clinic) at 12-month follow-up. RESULTS: Overall, 8% patients developed new onset persistent AF at 1-year follow-up. The incidence of AF at 1-year was 4% in patients treated with ACE inhibitors, 8% in patients taking AIIRAs or 5% on either drug. Although a trend towards a higher incidence of AF was observed at 1-year (10%) in patients not receiving either of these drugs, this was not statistically significant (P = 0.21, drug vs. no drug). The incidence of AF in patients with a previous history of paroxysmal AF or cardioversion was significantly higher (23%) than those patients without (5%), P < 0.0001. An odds ratio (95% CI) of 7.9 (2.3-27.8) was obtained. CONCLUSION: To confirm these interesting initial results and to investigate this important relationship further, larger prospective randomised controlled studies are required.
A convergent synthesis of the 11-oxa prostaglandin analogue AL-12182.
[reaction: see text] The 11-oxa prostaglandin analogue AL-12182 1 has potent topical ocular hypotensive activity. A convergent and concise general synthesis of this class of prostanoid was developed employing a stereoselective coupling reaction between a tetrahydrofuran core electrophile and a nucleophilic omega side chain component, providing a route that should be suitable for commercial scale production. The tetrahydrofuran core was assembled from dimethyl d-malate using a stereoselective beta-hydroxy ester dianion alkylation reaction.
How do different indicators of cardiac pump function impact upon the long-term prognosis of patients with chronic heart failure?
BACKGROUND: The prognosis of patients with mild-moderate chronic heart failure (CHF) over a long-term follow-up period is more difficult to predict than for patients with more severe CHF in the short term. This study assessed the prognostic value of various indicators of cardiac pump function to gain insight into how different aspects of organ function impact upon prognosis. METHODS: Unselected, consecutive patients with CHF (n = 219, 166 men, mean [+/-SD] age 56 +/- 13 years) who underwent symptom limited cardiopulmonary treadmill exercise testing with noninvasive estimation of cardiac output using carbon dioxide rebreathing techniques were followed up for a median period of 8.6 +/- 1.0 years in survivors. Cardiac power output (CPO) was calculated from the product of cardiac output and mean arterial pressure and cardiac reserve was estimated by subtracting resting from peak exercise CPO or cardiac output (CO). RESULTS: All-cause mortality was 36% (78 deaths). Survivors had a significantly greater cardiac pumping reserve with the greatest difference seen in CPO reserve (+57%) and CO reserve (+49%) (both P < .001). Although various direct and indirect indicators of cardiac function were predictive of outcome on univariate analyses, multivariate analysis using the Cox proportional hazards model identified CO reserve to be the independent variable predictive of all-cause mortality, with a hazard ratio (95% CI) of 0.682 (0.612-0.757, P < .001) for each L/min increase in cardiac output reserve. Survival at 10 years in patients with tertiles of good, moderate, or poor cardiac output reserve was 89%, 63%, and 36.1%, respectively (P < .001). CONCLUSION: In this long-term follow-up study involving a cohort of unselected ambulatory patients with mild-moderate CHF, cardiac pumping reserve measured noninvasively by cardiopulmonary exercise testing was found to be the strongest independent predictor of prognosis.
Effect of peri-operative red blood cell transfusion on 30-day and 1-year mortality following coronary artery bypass surgery.
OBJECTIVE: The purpose of this study was to examine the effect of peri-operative red blood cell (RBC) transfusion on 30-day and 1-year mortality following coronary artery bypass grafting (CABG). METHODS: We retrospectively analysed 3024 consecutive patients who underwent isolated CABG between January 1999 and December 2001. Patient records were linked to the National Strategic Tracing Service, which records all mortality in the UK. Thirty-day and 1-year mortality were derived from Kaplan-Meier curves. Confounding variables were controlled for by constructing a propensity score for the probability of receiving a transfusion from core patient characteristics including the lowest recorded laboratory haemoglobin (LL Hb) from a clinical chemistry database (C statistic 0.81). The propensity score and the comparison variable (transfusion versus no transfusion) were included in a Cox proportional hazards analysis, allowing calculation of adjusted hazard ratios (HR) and Kaplan-Meier survival curves. RESULTS: Nine hundred and forty (31.1%) patients received RBC transfusion during or within 72h of surgery. Predictors of the need for transfusion were LL Hb and lower body mass index, use of cardiopulmonary bypass, female sex, number of grafts, renal dysfunction, increased age, extent of disease, and prior CABG; these factors were all included in the propensity score. After 1-year of follow-up, 122 (4.03%) deaths occurred. The crude HR for 1-year mortality in patients transfused was 3.0 (P<0.001). After adjusting for the propensity score, re-operation for bleeding, peri-operative blood loss and post-operative complications, the adjusted 30-day mortality was 1.9% in transfused patients compared to 1.1% in patients not transfused (P<0.05). The adjusted HR for 1-year mortality in patients transfused was 1.88 (P<0.01). CONCLUSIONS: Peri-operative RBC transfusion after CABG is associated with an increased risk of mortality during a 1-year follow-up period, with a large proportion of deaths occurring within 30-days.
Dermal traction on the Ilizarov frame.
We report a technique of skin traction, which harnesses the biological and mechanical properties of skin. We have used this technique in open fractures to close or reduce the size of the wound, thereby avoiding the use of split skin grafts or free flaps and their resultant additional morbidity. This report summarises our early experience with this technique in seven patients. We describe the technique and the results so far.
Quality of life outcomes after coronary artery bypass graft surgery: relationship to neuropsychologic deficit.
OBJECTIVES: Neuropsychologic assessment after coronary artery bypass graft surgery indicates cognitive deficits, but data on their effect on health-related quality of life are relatively sparse. The present study assessed neuropsychologic deficits, self-reported health-related quality of life, and mood, together with proxy rating of patients' activities after bypass surgery. More specifically, the study examines the relationship between these varied outcome measures. METHODS: A prospective longitudinal assessment of 71 male patients was performed over a 6-month period: 1 week before surgery and postoperatively at 2 and 6 months. Within-patient change was assessed with the neuropsychologic test battery and procedures recommended by the Consensus Panel, the Short Form-36 to measure self-reported health-related quality of life, and the Hospital Anxiety and Depression Scale questionnaire to assess anxiety and depression. Proxy ratings were documented with the Functional Activities Questionnaire. RESULTS: Poor preoperative health-related quality of life was largely unrelated to medical variables. Cognitive deficit was found in 42% of patients at 2 months and 22% of patients at 6 months. Physical health-related quality of life improved, but benefit for emotional and social functioning was unconvincing, especially over the short term. Although cognitive deficits were largely unrelated to Short Form-36 health-related quality of life, and only partially related to anxiety and depression, they were associated with proxy ratings of patient functioning. CONCLUSIONS: Physical health-related quality of life benefits were confirmed, but adverse cognitive change and only limited emotional benefit were evident after coronary artery bypass graft surgery. Perceived physical gains are unrelated to any cognitive deficit, but the latter correlated with the emotional status of the patient 6 months after surgery and are of concern to close relatives. These issues should be addressed in patient care.
The unique role of diamorphine in British medical practice: a survey of general practitioners and hospital doctors.
AIMS: Diamorphine (heroin) is one of the longest established medications with a 130-year history. In British medicine diamorphine is sometimes used as a maintenance treatment for opiate addiction but is also routinely used in clinical practice to treat a number of general medical conditions. These uses are very different but are often confused by observers of the British system. The routine clinical use of diamorphine in medicine is unique to the UK, but this is not well known outside the UK. The present study investigates the use of diamorphine to treat medical conditions by general practitioners and by hospital doctors. METHOD: In a survey of 141 medical practitioners who had prescribed diamorphine for the treatment of a medical condition, data were collected on conditions prescribed for, numbers of patients, dosage, routes of administration, duration of treatment, worries about prescribing diamorphine and observed adverse effects. FINDINGS: Many doctors had prescribed diamorphine to a large number of patients. The four main conditions for which diamorphine had been prescribed in the previous year were myocardial infarction, palliative care, pulmonary oedema, and post-operative pain. More than half of the sample (57%) reported no reservations about prescribing diamorphine. Of the doctors (n = 60, 43%) who expressed worries, this was most often about possible problems of respiratory depression or respiratory arrest. Respiratory arrest/failure was also the most frequent observed adverse effect. Relatively few doctors reported worries about addiction. CONCLUSIONS: Although diamorphine was widely used and most doctors regarded it as a useful medication, there remains insufficient research information about current clinical practice. At a time when diamorphine may be coming under increased scrutiny, more detailed information is required of its uses and applications.
A report of a case: anesthetic management of a parturient with severe thrombotic stenosis of a mechanical aortic valve--an exercise in coordination of subspecialties.
The pregnant woman with valvular heart disease presents significant challenges to the obstetric, anesthesiology, and cardiology teams. Although successful outcomes for both mother and fetus are possible with coordinated medical care, the patient with a prosthetic valve who requires systemic anticoagulation provides a dilemma of insufficient anticoagulation leading to valve thrombosis versus the risks of maternal perinatal hemorrhage or fetal effects from oral or parenteral anticoagulants. This case report describes the peripartum management of a patient at 27 weeks' gestation with thrombus on a prosthetic aortic valve.
An efficient, palladium-catalyzed, enantioselective synthesis of (2R)-3-butene-1,2-diol and its use in highly selective Heck reactions.
A robust and scalable procedure for the palladium-catalyzed dynamic kinetic asymmetric transformation of 3,4-epoxy-1-butene into (2R)-3-butene-1,2-diol with water as the cosolvent is reported. Examination of the effects of solvent and temperature led to the identification of conditions that permitted use of 0.025 mol % catalyst, providing (2R)-3-butene-1,2-diol in 84% isolated yield and 85% enantiomeric excess. Subsequent Heck reactions with a diverse range of coupling partners are described and the influence of their electronic nature on maintaining the enantiopurity of the diol is discussed.
Effect of stress on prefrontal cortex function.
Stress is the major epigenetic factor that contributes to the etiology, pathophysiology, and treatment outcome of most psychiatric disorders. Understanding the mechanisms by which stress contributes to these processes can have important implications for improving therapeutic outcome. Considering that a dysfunctional prefrontal cortex has been implicated in many psychiatric disorders, such as schizophrenia and mood disorders, delineating mechanisms by which stress affects prefrontal cortex (PFC) function is critical to our understanding of the role of stress in influencing the disease process. This paper will review recent mechanistic information about the effects of stress on dopamine and glutamate neurotransmission in the PFC.
Left internal mammary artery to the left anterior descending artery: effect on morbidity and mortality and reasons for nonusage.
BACKGROUND: The left internal mammary artery to the left anterior descending artery is recognized as the gold standard for revascularization. Several studies have shown the benefits of the left internal mammary artery. However, a substantial portion of patients undergoing coronary artery bypass grafting does not receive this conduit. We sought to identify reasons for nonusage of the left internal mammary artery to the left anterior descending artery, while evaluating short- and medium-term outcomes. METHODS: Between April 1997 and September 2001 a total of 4406 consecutive patients underwent coronary artery bypass grafting with revascularization to the left anterior descending artery. All data were collected prospectively except reasons for nonusage of the left internal mammary artery. Logistic regression and Cox proportional hazards analyses were used to adjust in-hospital and medium-term outcomes, respectively. Selection bias was controlled by constructing a propensity score. A case note review was carried out to determine reasons for nonusage. RESULTS: A total of 4047 patients (91.8%) received the left internal mammary artery to the left anterior descending artery leaving 359 patients (8.2%) who did not. We found no difference in hospital mortality or morbidity, however, patients receiving the left internal mammary artery had a survival advantage at 4 years. Reasons for not using the left internal mammary artery were damage to the conduit (n = 44), poor flow (n = 43), poor lung function (n = 45), unstable symptoms (n = 24), vascular problems (n = 12), and 19 patients with "other" reasons (previous radiotherapy, chest wall deformity, and obese patients). Case notes had no reason stated for 146 patients and reasons for 26 patients were unobtainable. CONCLUSIONS: Left internal mammary artery usage is not associated with any increase in hospital mortality and morbidity, but these patients have better medium-term survival. Injury on harvesting, poor flow, and poor lung function were the most common reasons for not using this conduit.