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J D Poloniecki

Publications and source records attributed to J D Poloniecki.

16 recordsLinked to original sources
PubMed2004

Risk-adjusted prediction of operative mortality in oesophagogastric surgery with O-POSSUM.

INTRODUCTION: The present study was designed to develop a dedicated oesophagogastric model for the prediction of risk-adjusted postoperative mortality in upper gastrointestinal surgery (O-POSSUM). METHODS: Using 1042 patients undergoing oesophageal (n = 538) or gastric (n = 504) surgery between 1994 and 2000 the Portsmouth predictor equation for mortality (P-POSSUM) scoring system was compared with a standard logistic regression O-POSSUM model and a multilevel O-POSSUM model using the following independent factors: age, physiological status, mode of surgery, type of surgery and histological stage. RESULTS: The overall mortality rate was 12.0 per cent (elective mortality rate 9.4 per cent and emergency mortality rate 26.9 per cent). P-POSSUM overpredicted mortality (14.5 per cent), particularly in the elective group of patients. The multilevel model offered higher discrimination than the single-level O-POSSUM and P-POSSUM models (area under receiver-operator characteristic curve 79.7 versus 74.6 and 74.3 per cent). When observed to expected outcomes were evaluated, the multilevel O-POSSUM model was found to offer better calibration (Hosmer-Lemeshow chi(2) statistic 10.15 versus 10.52 and 28.80). CONCLUSION: The multilevel O-POSSUM model provided an accurate risk-adjusted prediction of death from oesophageal and gastric surgery for individual patients. In conjunction with a multidisciplinary approach to patient management, the model may be used in everyday practice for perioperative counselling of patients and their carers.

Adult↗
PubMed2004

Development of a dedicated risk-adjustment scoring system for colorectal surgery (colorectal POSSUM).

BACKGROUND: The aim of the study was to develop a dedicated colorectal Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (CR-POSSUM) equation for predicting operative mortality, and to compare its performance with the Portsmouth (P)-POSSUM model. METHODS: Data were collected prospectively from 6883 patients undergoing colorectal surgery in 15 UK hospitals between 1993 and 2001. After excluding missing data and 93 patients who did not satisfy the inclusion criteria, 4632 patients (68.2 per cent) underwent elective surgery and 2107 had an emergency operation (31.0 per cent); 2437 operations (35.9 per cent) for malignant and 4267 (62.8 per cent) for non-malignant diseases were scored. Stepwise logistic regression analysis was used to develop an age-adjusted POSSUM model and a dedicated CR-POSSUM model. A 60:40 per cent split-sample validation technique was adopted for model development and testing. Observed and expected mortality rates were compared. RESULTS: The operative mortality rate for the series was 5.7 per cent (387 of 6790 patients) (elective operations 2.8 per cent; emergency surgery 12.0 per cent). The CR-POSSUM, age-adjusted POSSUM and P-POSSUM models had similar areas under the receiver-operator characteristic curves. Model calibration was similar for CR-POSSUM and age-adjusted POSSUM models, and superior to that for the P-POSSUM model. The CR-POSSUM model offered the best overall accuracy, with an observed : expected ratio of 1.000, 0.998 and 0.911 respectively (test population). CONCLUSION: The CR-POSSUM model provided an accurate predictor of operative mortality. External validation is required in hospitals different from those in which the model was developed.

Adult↗
PubMed2003

Evaluation of POSSUM and P-POSSUM scoring systems in patients undergoing colorectal surgery.

BACKGROUND: The Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM) and Portsmouth POSSUM (P-POSSUM) equations were derived from a heterogeneous general surgical population and have been used successfully as audit tools to provide risk-adjusted operative mortality rates. Their applicability to high-risk emergency colorectal operations has not been established. METHODS: POSSUM variables were recorded for 1017 patients undergoing major elective (n = 804) or emergency (n = 213) colorectal surgery in ten hospitals. Subgroup analysis was performed to investigate the predictive capability of POSSUM and P-POSSUM in emergency and elective surgery and in patients in different age groups. RESULTS: The overall operative mortality rate was 7.5 per cent (POSSUM-estimated mortality rate 8.2 per cent; P-POSSUM-estimated mortality rate 7.1 per cent). In-hospital deaths increased exponentially with age. Both scoring systems overpredicted mortality in young patients and underpredicted mortality in the elderly (P < 0.001). Death was underpredicted by both systems for emergency cases, significantly so at a simulated emergency caseload of 47.9 per cent (P < 0.05). CONCLUSION: There is a lack of calibration of POSSUM and P-POSSUM systems at the extremes of age and high emergency workload. This has important implication in clinical practice, as consultants with a high emergency workload may seem to underperform when these scoring systems are applied. Recalibration or remodelling strategies may facilitate the application of POSSUM-based systems in colorectal surgery.

Adult↗
PubMed2001

Initial energy setting, outcome and efficiency in direct current cardioversion of atrial fibrillation and flutter.

OBJECTIVES: The purpose of this study was to design a more efficient protocol for the electrical cardioversion of atrial arrhythmias. BACKGROUND: Guidelines for electrical cardioversion of atrial arrhythmias recommend starting with low energy shocks, which are often ineffective. METHODS: We recorded the sequence of shocks in 1,838 attempts at cardioversion for atrial fibrillation (AF) and 678 attempts at cardioversion for atrial flutter. These data were used to calculate the probability of success for each shock of a standard series and the probability of success with a single shock at each intensity. In 150 cases, a rhythm strip with the time of each shock allowed us to calculate the time expended on unsuccessful shocks. RESULTS: We analyzed the effects of 5,152 shocks delivered to patients for AF and 1,238 shocks delivered to patients for atrial flutter. The probability of success on the first shock in AF of > 30 days duration was 5.5% at < 200 J, 35% at 200 J and 56% at 360 J. In atrial flutter, an initial 100 J shock worked in 68%. In AF of >30 days duration, shocks of < 200 J had a 6.1% probability of success; this fell to 2.2% with a duration >180 days. In those with AF for >180 days, the initial use of a 360 J shock was associated with the eventual use of less electrical energy than with an initial shock of < or =100 J (581 +/- 316 J vs. 758 +/- 433 J, p < 0.01, Mann-Whitney U test). CONCLUSIONS: An initial energy setting of > or =360 J can achieve cardioversion of AF more efficiently in patients than traditional protocols, particularly with AF of longer duration.

Analysis of Variance↗
PubMed2001

Relation between severity of left-ventricular hypertrophy and prognosis in patients with hypertrophic cardiomyopathy.

BACKGROUND: A previous study suggested that severe left-ventricular hypertrophy (maximum wall thickness > or = 30 mm) in patients with hypertrophic cardiomyopathy is associated with a risk of sudden cardiac death sufficient to warrant consideration for implantation of a cardioverter defibrillator (ICD). However, the prognostic significance of left-ventricular hypertrophy in relation to other clinical risk factors is poorly characterised. METHODS: We studied 630 patients consecutively referred to one hospital in London, UK (mean age 37 years [SD 16]; 382 male; mean follow-up 59 months). Patients underwent two-dimensional and doppler echocardiography, upright exercise testing, and Holter monitoring. FINDINGS: 39 patients died suddenly or had an appropriate ICD discharge; nine died from progressive heart failure; 11 from other cardiovascular causes and 23 from non-cardiac causes. There was a trend towards higher probability of sudden death or ICD discharge with increasing wall thickness (p=0.029, relative risk per 5 mm increment 1.31 [95% CI 1.03-1.66]). Of the 39 patients who died suddenly or had an ICD discharge, ten had a wall thickness of 30 mm or more. Patients with wall thickness of 30 mm or more had higher probability of sudden death or ICD discharge than patients with wall thickness less than 30 mm (p=0.049, 2.07 [1.00-4.25]. When considered together, the number of additional risk factors (one to three) was a better predictor of risk of sudden death or ICD discharge than wall thickness (p=0.0001, relative risk per additional factor 2.00 [1.43-2.79] vs p=0.058, 1.26 per 5 mm increment [0.99-1.60]). There was no relation between the pattern of hypertrophy and survival. INTERPRETATION: The risk of sudden death associated with a wall thickness of 30 mm or more in patients without other risk factors is insufficient to justify aggressive prophylactic therapy. Most sudden deaths occurred in patients with wall thickness less than 30 mm, so the presence of mild hypertrophy cannot be used to reassure patients that they are at low risk.

Adult↗
PubMed2001

Immunization and symptoms of atopic disease in children: results from the International Study of Asthma and Allergies in Childhood.

OBJECTIVES: This study tested the hypothesis that immunization is related to the prevalence of atopic disease in childhood. METHODS: We used data from the International Study of Asthma and Allergies in Childhood to perform an ecologic analysis of national and local immunization rates for tuberculosis, diphtheria and tetanus toxoids and pertussis (DTP), and measles and prevalence of atopic disease symptoms (asthma, allergic rhinoconjunctivitis, and atopic eczema). RESULTS: In 13- to 14-year-old children, there were significant negative associations with local birth-year immunization rates for DTP and measles but none with rates for tuberculosis. No associations were found in 6- to 7-year-old children. No associations with national immunization rates were found. CONCLUSIONS: International variations in childhood atopic diseases are unlikely to be explained by variations in immunization.

Adolescent↗
PubMed2000

Performance data and the mortuary register.

OBJECTIVE: To compare departmental records of deaths after cardiac surgery with the hospital's information system. DESIGN: Matched pairs comparisons: (i) historic record compared with current record from another source; (ii) contemporary records from different sources; and (iii) timed records from different sources. SETTING: Regional cardiothoracic units at St George's and St. Thomas's Hospitals. SUBJECTS: 2664 cardiac surgical operations at St George's between January 1992 and June 1994, 215 deaths in the cardiac surgery database at St Thomas's between April 1993 and March 1997, 120 in-hospital deaths received by the mortuary at St George's during June 1999. MAIN OUTCOME MEASURES: The difference in the number of in-hospital deaths from departmental, hospital, and mortuary sources. RESULTS: Four of 2664 operations (0.15%) had been incorrectly coded as leaving hospital alive. Fewer than 80% of the actual number of deaths after cardiac surgery at St Thomas's had been recorded on either the departmental database or the hospital administration system. For 9% of deaths received in the mortuary, it took more than 6 working days for the hospital record to be updated, and at the time of reporting 1 case had not been updated after 14 working days: the date of death was inaccurate in 4/113 (3.5%) of cases. CONCLUSIONS: The mortuary staff can contribute to improving the accuracy of body counts. Death rates and performance data should not be published without statistical peer review.

Cardiac Surgical Procedures↗
PubMed1999

Relation of mean heart rate and heart rate variability in patients with left ventricular dysfunction.

The new finding was that mean heart rate and heart rate variability were more closely coupled in patients with more advanced LV dysfunction. Mean heart rate explained a larger portion of variance in heart rate variability in patients in the lowest LVEF quartile than in those in the highest one. These results support our hypothesis that sympathetic activation in patients with more severe LV dysfunction results in closer correlation between heart rate and heart rate variability. Generally, the correlation between mean heart rate and heart rate variability is weak because heart rate and heart rate variability represent different modalities of cardiovascular regulation. Mean heart rate is normally determined by the interactions of both the sympathetic and parasympathetic nervous systems, whereas modulation of these activities, with different gains, determines the magnitude of heart rate variability. This results in great complexity in control of the heart by the autonomic nervous system. However, heart rate is likely to be more dominantly regulated by the sympathetic nervous system because of vagal withdrawal in patients with more severe LV dysfunction. The effect of sympathetic cardiac modulation has been shown to be more sluggish than that of the parasympathetic nervous system in beat-to-beat regulation of heart rate. This may result in more blunted heart rate variability concomitantly with elevated mean heart rate. Thus, variation in heart rate variability in any given mean heart rate is likely to be lower than in patients with more preserved LV function, and hence with more complex cardiac autonomic regulation with involvement of the parasympathetic nervous system. Indeed, even the slopes of regression lines between mean heart rate and heart rate variability were similar in the first and fourth LVEF quartile; the intercept of the regression line was significantly higher in the fourth quartile than in the first one. This further supports our hypothesis.

Adult↗
PubMed1999

Double-blind placebo-controlled trial of digoxin in symptomatic paroxysmal atrial fibrillation.

BACKGROUND: Digoxin is commonly prescribed in symptomatic paroxysmal atrial fibrillation (AF) but has never been evaluated in this condition. METHODS AND RESULTS: From a multicenter registry, 43 representative patients with frequent symptomatic AF episodes were recruited into a randomized, double-blind crossover comparison of digoxin (serum concentration, 1.29+/-0.35 nmol/L) and placebo. The study end point was the occurrence of 2 AF episodes (documented by patient-activated monitors), censored at 61 days. The median time to 2 episodes was 13.5 days on placebo and 18.7 days on digoxin (P<0. 05). The relative risk (95% CI) of 2 episodes (placebo:digoxin) was 2.19 (1.07 to 4.50). A similar effect was seen on the median time to 1 episode: increased from 3.5 to 5.4 days (P<0.05), relative risk 1. 69 (0.88 to 3.24). The mean+/-SD ventricular rates during AF recordings during placebo and digoxin treatment were 138+/-32 and 125+/-35 bpm, respectively (P<0.01). Twenty-four-hour ambulatory ECG recordings did not show significant differences in the frequency or duration of AF or in ventricular rate. CONCLUSIONS: Digoxin reduces the frequency of symptomatic AF episodes. However, the estimated effect is small and may be due to a reduction in the ventricular rate or irregularity rather than an antiarrhythmic action.

Ambulatory Care↗
PubMed1997

Daily time series for cardiovascular hospital admissions and previous day's air pollution in London, UK.

OBJECTIVE: To test for a significant association between air pollution and emergency hospital admissions for circulatory diseases (international classification of diseases-9 390-459) in London, England, that would be consistent with a causal effect of pollution on the previous day. METHODS: Long term concurrent trends, temperature, humidity, day of the week, influenza epidemic of 1989, and cyclical covariations with periodicity > 20 days in daily measures of pollution and admissions for 1987-94 were allowed for. RESULTS: There were 373556 admissions. No association was found between O3 and circulatory diseases. Four other pollutants were associated with acute myocardial infarction and circulatory diseases combined. P values and attributable cases (95% confidence intervals) for acute myocardial infarction were: black smoke P = 0.003, 2.5% (0.8% to 4.3%); NO2 P = 0.002, 2.7% (0.8% to 4.6%); CO P = 0.001, 2.1% (0.7% to 3.5%); and SO2 P = 0.0006, 1.7% (0.7% to 2.6%). There were also associations between black smoke and angina (P = 0.02), NO2 and arrhythmia (P = 0.04), and CO and other circulatory diseases (P = 0.004), but none with heart failure. Acute myocardial infarction was the only diagnosis for which there were significant associations with and without adjustment for cyclical terms. The associations with acute myocardial infarction were significant only in the cool season. CONCLUSION: Population data were consistent with 1 in 50 heart attacks currently presenting at London hospitals being triggered by outdoor air pollution. Further research is now needed to investigate whether background concentrations of black smoke, NO2, CO, and SO2 are a preventable cause of myocardial infarction. These results, if applied to all myocardial infarctions in the United Kingdom, indicate a potential saving of 6000 heart attacks a year.

Air Pollutants↗
PubMed1994

Computation of multifactorial receiver operator and predictive accuracy characteristics.

The computation of the so-called receiver operator characteristics (i.e. functions that assign the maximum specificity to each value of sensitivity) is simple when the characteristics are based on univariate data. On the contrary, multivariate characteristics are difficult to compute, as the complexity of their calculation increases exponentially with the dimension of the data. This paper describes an algorithm for computation of multivariate receiver operator characteristics and derived functions (namely positive and negative predictive characteristics). The algorithm is based on several concepts that increase its computational efficiency. The most important of them is a pre-sorting of the data in each dimension and the division of each dimension into groups in which the positive and negative cases are 100% stratified. The paper also presents a risk stratification study that utilised this algorithm. The study was aimed at identifying those survivors of acute myocardial infarction who are at risk of early death. A cohort of 539 patients was stratified based on time-domain (three variables) and spectral turbulence (six variables) indices of signal-averaged electrocardiogram. The computing times of the algorithm in this study are presented in the text, and the efficiency of the computation is discussed in detail.

Algorithms↗
PubMed1991

Prognostic value of thallium-201 perfusion defects in idiopathic dilated cardiomyopathy.

To assess the prognostic significance of thallium-201 perfusion defects in patients with idiopathic dilated cardiomyopathy (IDC), 43 patients underwent thallium scintigraphy in addition to clinical, echocardiographic, angiographic and hemodynamic evaluation. Eleven patients had no significant thallium perfusion abnormality, 19 had multiple small defects and 13 had a large defect. During 3.2 +/- 2.2 years, 14 patients had disease-related mortality. The patients who died had a higher incidence of ventricular tachycardia (71 vs 31%; p less than 0.02), increased cardiothoracic ratio (60 +/- 6 vs 54 +/- 6; p = 0.005), decreased fractional shortening (11 +/- 6 vs 15 +/- 5; p less than 0.05), increased pulmonary wedge pressure (15 +/- 7 vs 10 +/- 6 mm Hg; p = 0.05), increased left ventricular end-diastolic pressure (21 +/- 8 vs 14 +/- 6 mm Hg; p = 0.02) and abnormal thallium perfusion defects (13 of 14 vs 16 of 26; p less than 0.05) compared with survivors. Age, gender, left ventricular end-systolic and end-diastolic dimensions, cardiac index and ejection fraction were not statistically different in the survivors versus the patients who died. Kaplan-Meier survival estimates at 1, 3 and 5 years were 100% in patients without significant perfusion abnormality; 89, 77 and 64%, respectively, in patients with multiple small defects; and 84, 76 and 30%, respectively, in patients with a large defect (p less than 0.025 by log rank test).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1990

Prognostic significance of radionuclide-assessed diastolic function in hypertrophic cardiomyopathy.

To evaluate the prognostic significance of diastolic function in hypertrophic cardiomyopathy (HC), technetium-99m gated equilibrium radionuclide angiography, acquired in list mode, was performed in 161 patients. Five diastolic indexes were calculated. During 3.0 +/- 1.9 years, 13 patients had disease-related deaths. With univariate analysis, these patients were younger (29 +/- 20 vs 42 +/- 16 years; p less than 0.05), had a higher incidence of syncope (p less than 0.025), dyspnea (p less than 0.001), reduced peak filling rate (2.9 +/- 0.9 vs 3.4 +/- 1.0 end-diastolic volume/s; p = 0.09) with increased relative filling volume during the rapid filling period (80 +/- 7 vs 75 +/- 12%; p = 0.06) and decreased atrial contribution (17 +/- 7 vs 22 +/- 11%; p = 0.07). Stepwise discriminant analysis revealed that young age at diagnosis, syncope at diagnosis, reduced peak ejection rate, positive family history, reduced peak filling rate, increased relative filling volume by peak filling rate and concentric left ventricular hypertrophy were the most statistically significant (p = 0.0001) predictors of disease-related death (sensitivity 92%, specificity 76%, accuracy 77%, positive predictive value 25%). Discriminant analysis excluding the diastolic indexes, however, showed similar predictability (sensitivity 92%, specificity 76%, accuracy 78%, positive predictive value 26%). To obtain more homogeneous groups for analysis, patients were classified as survivors (116) or electrically unstable (40), including sudden death, out-of-hospital ventricular fibrillation and nonsustained ventricular tachycardia during 48-hour ambulatory electrocardiography, and heart failure death or cardiac transplant (5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Atrial fibrillation in hypertrophic cardiomyopathy: a longitudinal study.

The clinical outcome of 52 consecutive patients with hypertrophic cardiomyopathy who developed paroxysmal (less than 1 week) or established (greater than or equal to 1 week) atrial fibrillation between 1960 and 1985 was examined retrospectively and compared with that of a matched group of patients with hypertrophic cardiomyopathy and sinus rhythm. Follow-up study until death or the present ranged from 6 months to 24 years (median 11 years) from diagnosis and from 6 months to 22 years (median 7 years) from the onset of atrial fibrillation. Atrial fibrillation was present in 6 patients at the time of diagnosis, whereas it developed subsequently in 46. The acute onset of arrhythmia was associated with a change in symptoms in 41 (89%) of the 46. After initial treatment of acute atrial fibrillation, sinus rhythm was restored in 29 (63%) of the 46 patients; 43 (93%) of the 46 returned to their original symptom class. Stepwise logistic regression revealed that shorter duration of arrhythmia and amiodarone therapy were the most powerful predictors of return to sinus rhythm. Sinus rhythm was maintained during a median follow-up period of 5.5 years in 22 of the 29 patients in whom it was restored after initial therapy. During follow-up study, 25 of the 52 patients were treated with conventional therapy alone and 7 with amiodarone alone. Amiodarone therapy was associated with maintenance of sinus rhythm, fewer alterations in drug therapy, fewer embolic episodes and fewer attempted direct current cardioversions (during a shorter follow-up period).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Acebutolol in the treatment of diabetic patients with hypertension.

A double-blind, parallel group comparison study was carried out in 20 diabetic patients with mild to moderate hypertension to assess the effectiveness and tolerance of acebutolol compared with placebo. After a 4-week wash-out period on placebo, patients received either 400 mg acebutolol or placebo once daily for 12 weeks and then placebo for a further 4 weeks. The results showed that acebutolol was more effective than placebo in lowering raised blood pressure in these patients. No deterioration in diabetic control occurred during the study and no significant side-effects of the drug were observed compared with placebo. In particular, the previously described side-effects of beta-blocker therapy in diabetic patients were not observed as a clinical problem in this study.

Acebutolol↗