Use of appropriate statistical tools in biomedical research: Current trend & status.

Background & objectives: Due to lack of appropriate statistical knowledge, published research articles contain various errors related to the design, analysis and interpretation of results in the area of biomedical research. If research contains statistical error, however, costly, it may be of no use and the purpose of the investigation gets defeated. Many biomedical research articles published in different peer reviewed journals may retain several statistical errors and flaws in them. This study aimed to examine the trend and status of application of statistics in biomedical research articles. Study design, sample size estimation and statistical measures are crucial components of a study. These points were evaluated in published original research articles to understand the use or misuse of statistical tools. Methods: Three hundred original research articles from the latest issues of selected 37 journals were reviewed. These journals were from the five internationally recognized publication groups (CLINICAL KEY, BMJ Group, WILEY, CAMBRIDGE and OXFORD) accessible through the online library of SGPGI, Lucknow, India. Results: Among articles assessed under present investigation, 85.3 per cent (n=256) were observational, and 14.7 per cent (n=44) were interventional studies. In 93 per cent (n=279) of research articles, sample size estimation was not reproducible. The simple random sampling was encountered rarely in biomedical studies even though none of the articles was adjusted by design effect and, only five articles had used randomized test. The testing of assumption of normality was mentioned in only four studies before applying parametric tests. Interpretation & conclusions: In order to present biomedical research results with reliable and precise estimates based on data, the role of engaging statistical experts need to be appreciated. Journals must have standard rules for reporting study design, sample size and data analysis tools. Careful attention is needed while applying any statistical procedure as, it will not only help readers to trust in the published articles, but also rely on the inferences the published articles draw.

Long-term outcomes post chronic total occlusion intervention-implications of completeness of revascularization.

BACKGROUND: Long term clinical outcomes post chronic total occlusion (CTO) intervention may depend not only on CTO success/failure alone but also on Completeness of revascularization. OBJECTIVES: To determine long term outcomes post CTO intervention and relate them to both success versus failure and Complete Revascularization (CR) versus Incomplete Revascularization (IR). METHODS: Consecutive patients taken up for CTO intervention with at-least one CTO vessel between Jan 2006 to Dec 2015 were included. Clinical, procedural and follow up details were recorded in a pre-specified custom made software. Primary endpoint of the study was survival free of major adverse event individual, death, myocardial infarction (MI), repeat revascularisation (percutaneous coronary intervention [PCI], or coronary artery bypass grafting (CABG) and recurrent or continued angina. Each individual adverse event was considered as a secondary end point. RESULTS: A total of 632 patients were enrolled in study with follow up data available in 549 (86%) constituting the study group with 490 (89.3%) success and 59 (11.7%) failure. Complete revascularization (CR) was obtained in 410 (74.7%). Follow up was median 2.9 years with inter-quartile range 1.1-4.8 years. Kaplan Meier survival analysis showed a better EFS with both CTO success versus failure (P = 0.03)and CR versus IR (P = 0.017). Individual adverse outcomes however were not significantly different in CTO success versus failure group but significantly better when analyzed with respect to CR versus IR including death (P = 0.049) and recurrent angina (P = 0.024). Repeat intervention and MI were not different by either analysis. CONCLUSIONS: Successful CTO PCI results in a better long term event free survival but the difference between the groups is more if analyzed with respect to completeness of revascularization rather than CTO success/failure alone.

Multiparametric imaging-based differentiation of lymphoma and glioblastoma: using T1-perfusion, diffusion, and susceptibility-weighted MRI.

AIM: To compare the diagnostic performance of T1 perfusion magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and susceptibility-weighted imaging (SWI) for differentiating primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM). MATERIALS AND METHODS: This retrospective study comprised a cohort of 70 patients with glioblastoma and 30 patients with PCNSL. T1 perfusion MRI-derived rCBV_corr (leakage corrected relative cerebral blood volume), apparent diffusion coefficient (ADC) derived from DWI, and intratumoural susceptibility signals intensity (ITSS) measured on SWI were evaluated in these 100 patients. The Mann-Whitney U-test was used for pairwise comparison between groups. The diagnostic performance for differentiating PCNSL from glioblastoma was evaluated by using univariate and multivariable logistic regression analyses and receiver operating characteristic (ROC) analysis. RESULTS: Minimum ADC, maximum rCBVs_corr, kep (back flux exchange rate), and ITSS scores were significantly lower in patients with PCNSL than in those with glioblastoma (p<0.05). On ROC analysis, ITSS showed the best discrimination ability for differentiation of GBM and PCNSL with an area under the ROC curve (AUC) of 0.80. rCBV_corr and ADC showed AUCs of 0.68 and 0.63, respectively. Multiparametric assessment using ADC, rCBV_corr, kep, and ITSS scores significantly increased the diagnostic ability for differentiating PCNSL from GBM as compared to mean ADC, mean rCBV_corr, and ITSS alone or a combination of these parameters. The multiparametric model could correctly discriminate 84% of tumours with a sensitivity and specificity of 90% and 70% with an AUC of 0.92. CONCLUSION: Multiparametric MRI evaluation using DWI, T1 perfusion MRI, and SWI enabled reliable differentiation of PCNSL and GBM in the majority patients, and these results support an integration of advanced MRI techniques for the diagnostic work-up of patients with these tumours.

Lack of association between Glu298Asp polymorphism and coronary artery disease in North Indians.

Nitric Oxide (NO) is an important molecule carrying number of different functions in humans. Published studies suggest that it may inhibit several key steps involved in the pathogenesis of atherosclerosis. Inhibition or reduction of NO due to Glu298Asp polymorphism may accelerate atherosclerosis. The aim of this study was to determine whether Glu298Asp polymorphism is implicated in the pathogenesis of coronary artery disease (CAD) among North Indian population from the state of Uttar Pradesh, India. We selected 253 CAD patients and 174 healthy, normotensive, non-diabetic controls, which were matched for gender and ethnicity. The Glu298Asp (rs1799983) variant was detected by genotyping subjects, using a polymerase chain reaction followed by restriction fragment length polymorphism. There was no significant difference found in the genotypic and allelic frequencies between patients and controls. Our study indicated that Glu298Asp polymorphism does not play any critical role in the pathogenesis of CAD, at least in North Indian population.

Patterns and determinants of dyslipidaemia in 'Young' versus 'Not so Young' patients of coronary artery disease: a multicentric, randomised observational study in northern India.

AIMS: The aims of the study were to ascertain difference in lipid levels of 'Young' onset of coronary artery disease (CAD) (≤ 45 years) vs. 'Not so Young' onset of CAD (≥ 55 years) among north Indians and also to investigate determinants of 'dyslipidaemia' in CAD patients. METHODS: This was a prospective, multicentric, randomised, observational study carried in eight centres of UP, India. All blood investigations were performed employing a central laboratory. RESULTS: Out of a total 435 patients studied, 218 were in the 'young group' (YG) and 235 were in the 'Not so Young Group' (NSYG). Dyslipidaemia was more common in YG as evident by significantly higher levels of total cholesterol, triglycerides, low- and very low-density lipoprotein cholesterol as compared to NSYG. Diabetes, hypertension, urban lifestyle, and family history of CAD were found to be important determinants of dyslipidaemia in YG. CONCLUSION: We conclude that lipid levels among north Indians are significantly higher in younger patients with CAD when compared with elderly.

Patient controlled sedation during central neuraxial anesthesia.

BACKGROUND: Patient controlled sedation (PCS) gives liberty to patients to choose the time of sedative administration to attain a desired level of comfort. AIMS: The PCS use was evaluated in patients during surgery under central neuraxial blockade. SETTINGS AND DESIGN: Prospective, cross-sectional, clinical study on consecutive patients in a tertiary care university hospital. MATERIALS AND METHODS: PCS technique, using propofol (1%) 2 ml in 2 min was used in 160 adult patients undergoing urologic procedures under central neuraxial block. We observed the time to first PCS activation by patient, duration of surgery, propofol dose, sedation score, hemodynamic stability, patient's acceptability, and the factors correlating with the PCS use. STATISTICAL ANALYSIS USED: Non-parametric two-tailed Pearson's test, univariate correlation analysis for the factors favoring PCS use followed by multivariate logistic regression analysis amongst correlating factors. RESULTS: In our cohort, the majority (83%) of the patients activated PCS during surgery under central neuraxial blocks at median time of 30 min and (17%) did not activate PCS. Female patients activated sedation earlier (median 15 min) than male patients (median 30 min). All patients were hemodynamically stable and without significant side effects. Multivariate analysis showed that sedative use significantly ( P < 0.05) correlated with female gender (odds ratio-3.54 [IR-2.64 to 4.73]) and prolonged surgery (>90 min). Majority (91%) of patients rated PCS technique excellent to good. CONCLUSIONS: PCS was very well accepted by patients during central neuraxial block. Propofol regimen (2 ml in 2 min) in PCS was safe, as it caused neither apnea nor significant hypotension.

Study to Test and Operationalize Preventive Approaches for CKD of Undetermined Etiology in Andhra Pradesh, India.

INTRODUCTION: High prevalence of chronic kidney disease (CKD) not associated with known risk factors has been reported from coastal districts of Andhra Pradesh. The Study to Test and Operationalize Preventive Approaches for Chronic Kidney Disease of Undetermined Etiology in Andhra Pradesh (STOP CKDu AP) aims to ascertain the burden (prevalence and incidence) of CKD, the risk factor profile, and the community perceptions about the disease in the Uddanam area of Andhra Pradesh. METHODS: Study participants will be sampled from the Uddanam area using multistage cluster random sampling. Information will be collected on the demographic profile, occupational history, and presence of conventional as well as nonconventional risk factors. Glomerular filtration rate (GFR) will be estimated using the Chronic Kidney Disease Epidemiology Collaboration equation, and proteinuria will be measured. All abnormal values will be confirmed by repeat testing after 3 months. Cases of CKD not associated with identified etiologies will be identified. Biospecimens will be stored to explore future hypotheses. The entire cohort will be followed up every 6 months to determine the incidence of CKD and to identify risk factors for decline in kidney function. Qualitative studies will be performed to understand the community perceptions and expectations with respect to the interventions. IMPLICATIONS: CKD is an important public health challenge in low- and middle-income countries. This study will establish the prevalence and determine the incidence of CKD not associated with known risk factors in a reported high-burden region, and will provide insights to help design targeted health systems responses. The findings will contribute to the policy development to tackle CKD in the region and will permit international comparisons with other regions with similar high prevalence.

Scales of measurement and presentation of statistical data.

Measurement scale is an important part of data collection, analysis, and presentation. In the data collection and data analysis, statistical tools differ from one data type to another. There are four types of variables, namely nominal, ordinal, discrete, and continuous, and their nature and application are different. Graphs are a common method to visually present and illustrate relationships in the data. There are several statistical diagrams available to present data sets. However, their use depends on our objectives and data types. We should use the appropriate diagram for the data set, which is very useful for easily and quickly communicating summaries and findings to the audience. In the present study, statistical data type and its presentation, which are used in the field of biomedical research, have been discussed.

Preceding infections and anti-ganglioside antibodies in patients with Guillain-Barré syndrome: a single centre prospective case-control study.

Preceding infections and anti-ganglioside antibodies were assessed among 80 Guillain-Barré syndrome (GBS) patients and 125 controls. Previous infections were more frequent among GBS patients than among controls (p <0.0001), and had a significant association with axonal subtype compared with acute inflammatory demyelinating polyneuropathy (AIDP) (29/46 vs. 10/34 patients; p <0.05). Campylobacter jejuni (26%) was the most common preceding infection among GBS patients, followed by Mycoplasma pneumoniae (15%). Anti-ganglioside antibodies were detected more frequently among GBS patients than among controls (65/80 vs. 13/125; p <0.001), and a higher proportion of axonal cases had these antibodies than did AIDP patients (43/46 vs. 22/34; p <0.01).

Trends, prospects and deprivation index of disability in India: Evidences from census 2001 and 2011.

BACKGROUND: Since the dawn of civilization, disabilities have existed in various dimensions of human life. World Health Organization (WHO) defines disability as an umbrella term, covering impairments, activity limitations, and participation restrictions. Globally, approximately 1 billion people have some form of disability, and approximately 20% have significant functioning impairments. OBJECTIVE: This study aims to estimate the level, trends and prospects of disability in 640 districts of India. Data for the present study has been taken from Census of India, 2001 and 2011. METHODS: A Disability Index was calculated at the district level, and state level indexing was done using the Disability Deprivation Index. The population for the year 2021 was projected using the exponential growth rate method. The Disability Deprivation Index was calculated using child labor, adult unemployment, illiteracy, and the ratio of beggars in the disabled population. RESULTS: The study reveals that the proportion of the disabled population in India was 2.10% in 2001, which increased to 2.21% in 2011. According to the Disability Deprivation Index, Maharashtra was the best-performing state in 2011. There were 4.90 million new cases of disability in India during 2001-11, out of which 1.52 million cases belonged to non-congenital disability. CONCLUSIONS: There is a rise in the disabled population in India, which needs special attention. The working status of the disabled is gloomy. The majority of the disabled people are non-working and need adequate rehabilitation measures that would facilitate employment.

Pan masala habits and risk of oral precancer: A cross-sectional survey in 0.45 million people of North India.

OBJECTIVES: This cross-sectional community based study was conducted to estimate the prevalence of consumption habits for non tobacco pan masala (ASU) and the risk of developing oral precancer in North India. METHODS: This study was conducted in the old town of Lucknow city in the state of Uttar Pradesh in India. Subjects residing for more than 6 months and aged 15 years or above, were enrolled in the study after their informed consent. A two page survey tool was used to collect the data. A three times more matched sample of non users was randomly obtained from this data to analyze and compare the final results. RESULTS: 0.45 million subjects were surveyed. Majority of tobacco users were in the age group of 20-35 years among males and 35-39 years among females. Consumption of non tobacco pan masala among males as well as females was most common in 15-19 years of age group. Prevalence of oral precancer (leukoplakia, submucous fibrosis, erythroplakia, lichen planus, smokers palate and verrucous hyperplasia) was 3.17% in non tobacco pan masala users and 12.22% in tobacco users. The odds of developing oral precancer in non tobacco pan masala users was 20.71 (18.79-22.82) and in tobacco users was 88.07 (84.02-92.31) at 95% confidence interval against non users of both. CONCLUSION: The odds of developing oral precancer even with consumption of pan masala is high, even when it is consumed without tobacco. It is hence recommended to discourage this habit.

Disparity in maternal, newborn and child health services in high focus states in India: a district-level cross-sectional analysis.

OBJECTIVES: To examine the level and trend in the coverage gap of a set of interventions of maternal and child health services using a summary index and to assess the disparity in usage of maternal and child health services in the districts of high focus states of India. DESIGN: Data for the present study are taken from the Annual Health Survey (AHS), 2010-2013 and Census of India, 2011. SETTINGS: This study used secondary data from states having higher mortality and fertility rates, termed as high focus states in India. PARTICIPANTS: District-level information regarding children aged 12-23 months and ever married women aged 15-49 years has been extracted from the AHS (2010-2013), and household amenities, female literacy and main workforce information has been obtained from the Census of India 2011. MEASURES: 2 summary indexes were calculated first for maternal and child health services and another for socioeconomic and development status, using data from AHS and Census. Cronbach's α was used to assess the internal consistency of the items used in the index. RESULTS: The result shows that the coverage gap is highest in Uttar Pradesh (37%) and lowest in Madhya Pradesh (21%). Converge gap and socioeconomic development are negatively correlated (r=-0.49, p=0.01). The average coverage gap was highest in the lowest quintile of socioeconomic development. There was an absolute change of 1.5% per year in coverage gap during 2009-2013. In regression analysis, the coefficient of determination was 0.24, ß=-30.05, p=0.01 for a negative relationship between socioeconomic development and coverage gap. CONCLUSIONS: There is a significant disparity in the usage of maternal and child healthcare services in the districts of India. Resource-rich people (urban residents and richest quintile) are way ahead of marginalised people (rural residents and poorest quintile) in the usage of healthcare services.

Left main PCI: An observational analysis from large single-centre experience.

BACKGROUND: Although trials have shown efficacy of unprotected left main percutaneous coronary intervention (uLMPCI), data from Indian subcontinent are lacking. Hence, we planned this observational analysis of single-center uLMPCI data. OBJECTIVES: To study long-term outcome after uLMPCI and identify predictors of adverse outcome. METHODS: Case details of 62 consecutive patients of uLMPCI between 2006 and 2013 were retrieved from a computerized database wherein detailed records were maintained. RESULTS: Mean follow-up duration was 669.8±404.2 days. Procedural success rate was 98.4%. Primary endpoint was composite of major adverse cardiovascular and cerebrovascular events (MACCE), which included cardiac death (CD), cerebrovascular accident (CVA), myocardial infarction (MI), and need for repeat intervention (RI) at three years. MACCE occurred in 13 (20.9%) patients. Cardiac death (CD), (including possible stent thrombosis), RI, and CVA occurred in 6 (9.7%), 5 (8%), and 2 (3.2%) patients, respectively. Overall three-year MACCE-free survival rate was 76.7%. Event-free survival rate was similar among patients who underwent uLMPCI alone and patients who underwent uLMPCI along with additional one-vessel PCI [(88.9% vs 81.8%), p=0.492], while survival rate was lower in patients who underwent uLMPCI along with PCI of additional two or more vessels (40%, p=0.036). Patients with syntax score ≤32 had higher event-free survival rate than those with syntax score >32 [(87.1% vs 33.3%), p=0.001]. Syntax score >32 was the only independent predictor of adverse outcome. CONCLUSION: uLMPCI is safe and effective alternative to CABG for LM alone and LM plus single-vessel disease with syntax score ≤32.

Role of bilirubin, vitamin C and ceruloplasmin as antioxidants in coronary artery disease [CAD].

A study has been carried out on 250 CAD patients to see how the serum levels of three antioxidants i.e., Vitamin C, Bilirubin and Ceruloplasmin are related to the CAD risk factors and characteristics in these patients. The number of severe category CAD patients declined by 7-18% with increasing serum levels of the three antioxidants and, triple vessel disease declined by 14-20%. A decline of 39% in Myocardial Infarction (MI) occurred with increasing serum Ceruloplasmin. Serum Ceruloplasmin was significantly lower in the MI group compared to the non MI group CAD patients. There was a steady and a significant decline in the mean values of serum levels of cholesterol, Triglyceride, VLDL cholesterol along with BMI with increasing serum level. The study indicates that with increasing serum levels of the three antioxidants studied, the % MI along with % Triple vessel disease and severity of CAD goes down suggesting that the modifiable risk factors have to be suitably modified in order to maintain a reasonably high level of these antioxidants, as the risk factors are inversely related to the serum antioxidant levels.

Epidemiology of substance abuse in the population of Lucknow.

BACKGROUND: Habit of consuming tobacco and areca-nut containing substances is in vogue in Lucknow as a part of the Nawabi culture. Hence, this study was planned with an aim to generate evidence for the prevalence of habits of substance abuse by the population of Lucknow and know their socio-demographic profile. METHODOLOGY: Population based cross-sectional study was conducted by organizing oral health check-up camps in randomly selected rural and urban parts of Lucknow, the capital city of Uttar Pradesh, which is the most populated state of India. Patients were enrolled after obtaining informed consent. A structured and validated questionnaire based tool was administered by a team of trained dental surgeons for collecting the desired information through interview and their oral cavity examination. RESULTS: A total of 3437 subjects were enrolled in the study, out of which 82.9% were male and 17.1% were female. Among them, 64.6% subjects belonged to rural domiciliary status, by religion, 80.6% and 18.5% of the subjects were Hindu and Muslims respectively. The most prevalent habit was consumption of smokeless tobacco substances, of which pan masala with tobacco (gutkha) was the most prevalent substance of abuse. CONCLUSION: Smokeless tobacco consumption was highly prevalent in the population surveyed. It is recommended to formulate and implement strong preventive strategies. Also, steps should be taken to increase the awareness of the harmful consequences of these habits.

Modulation of autoimmune diseases by nitric oxide.

Nitric oxide (NO) is an intercellular messenger that performs a number of functions, including neurotransmission, vasodilatation, inhibition of platelet aggregation, and modulation of leukocyte adhesion. NO has recently been shown to act as a potent cytotoxic effector molecule as well as to play an important role in the pathogenesis of organ-specific autoimmunity. NO may also modulate the immune response by interfering with Th1/Th2 balance in autoimmune diseases. This review will discuss the role of NO and nitric oxide synthase (NOS) in pathophysiologic and therapeutic implications in various autoimmune diseases with particular reference to T helper-1 (Th1) and T helper-2 (Th2) cytokines.

The magnetic resonance renogram in renal transplant evaluation using dynamic contrast-enhanced MR imaging.

To assess the role of the dynamic gadolinium DTPA (Gd-DTPA) magnetic resonance (MR) renogram in differentiating various causes of renal allograft dysfunction, contrast-enhanced MR imaging studies were performed in 5 normal renal allografts, 5 patients with acute rejection (AR), and 7 patients with cyclosporine nephrotoxicity. Time-versus-signal intensity (SI) curves were plotted. Normal renal allografts showed a rapid increase and slow decay, with a definite peak in cortical (CX) SI curves (peak mean signal intensity (Amax 338.6 +/- 46.5). The outer medullary (OM) (Amax 306.5 +/- 59) and inner medullary (IM) (Amax 263.4 +/- 47.4) curves did not show a definite peak. The OM curve slowly reached a steady state and caught up with the CX curve. AR episodes were characterized by a blunted uprise and delayed peak of CX (Amax 180 +/- 70.9) and a low-amplitude vascular phase with a slow constant uprise of the inner medullary curve (Amax 120.35 +/- 42.4). The OM signal intensity curve (Amax 150.73 +/- 78) failed to catch up with the CX curve. The maximum amplitude of SI curves in CsA-induced allograft dysfunction were low, with no definite peak, and CX, OM, and IM curves ran parallel to each other with a constant gap. Dynamic Gd-DTPA, MR imaging is a noninvasive technique that shows distinct characteristics in acute rejection, cyclosporine nephrotoxicity, and normally functioning renal allografts.

Variations of intracavitary applicator geometry during multiple HDR brachytherapy insertions in carcinoma cervix and its influence on reporting as per ICRU report 38.

PURPOSE: This paper examines the extent of variation in the applicator geometry during multiple high dose rate (HDR) intracavitary brachytherapy (ICBT) applications and its impact on reporting as per ICRU report 38. MATERIALS AND METHODS: Eighty orthogonal radiographs from 20 consecutive patients of carcinoma cervix (FIGO stages, IIA-IIIB) having four HDR ICBT applications of 6 Gy each at weekly intervals following teletherapy were evaluated. The applicator consisted of a flexible intrauterine tandem (IUT) independent of the ovoid assembly. The applicator geometry was evaluated in terms of: alpha angle, beta angle, intrauterine length (IUTL), interovoid (IOV), os to right ovoid (ORT) and os to left ovoid (OLT) distances along with vertical (VDL) and anteroposterior displacements (ADL) of the os with respect to the ovoids. The Cartesian co-ordinates (X, Y, and Z) of the IUT tip, centre of both ovoids and os were also measured. Doses to right point A (ARD), left point A (ALD), along with a reference volume of 6 Gy for ICRU height (IRH), width (IRW), thickness (IRT) and volume (IRV) were estimated for each application. RESULTS: Highly significant differences (P<0.001) between four insertions in any given patient across 20 patients for alpha angle, beta angle, IUTL, IOV, ORT, VDL, co-ordinates of the IUT, ovoids and os were observed, except for ADL (P=0.041) and OLT (P=0.247). As a consequence, variations were observed in ARD (P=0.027), ALD (P=0.017); IRH, IRW, IRT and IRV (all P<0.001). Applicator factors which influenced the various dose specification parameters were: beta angle and ORT for both ARD and ALD; UTLN, VDL and ORT for IRH; UTLN and IOV for IRW; UTLN for IRT and VDL for the 6 Gy IRV. CONCLUSIONS: A significant variation of the applicator geometry and its movement was observed in patients undergoing multiple HDR ICBT. This could have implications for reporting dose and volume specifications as required by ICRU report 38.

Prognostic factors for persistent distal renal tubular acidosis after surgery for posterior urethral valve.

Risk factors, including age at presentation, age at surgery, time between presentation and surgery, urodynamic abnormalities, and vesicoureteric reflux, were prospectively studied for the development of distal renal tubular acidosis (DRTA) before surgery and persistent DRTA after surgery in 24 boys with posterior urethral valve (PUV) with normal serum creatinine levels. DRTA was persistent in 11 of 17 boys (65%) at the end of follow-up after intervention. For the development of DRTA before surgery, only a longer time between presentation and surgery (intervening period) turned out to be a significant risk factor on multivariate analysis (beta = -0.13; P = 0.04). Boys with persistent DRTA after surgery had older age at presentation (P = 0.03), older age at surgery (P = 0.001), a longer intervening period (P = 0.0007), and bilateral or severe unilateral reflux (P = 0.04) before surgery. On univariate logistic regression, age at surgery (beta = -0.07; P = 0.04) and intervening period (beta = -0.13; P = 0.02) were found to be significant risk factors for persistent DRTA, but on multivariate analysis, only intervening period was found to be significant (beta = -0.13; P = 0.02). A delay in intervention after noticing voiding symptoms can predict a high incidence of DRTA before intervention and persistent DRTA after surgery in boys with PUV.

Management of persistent atrial fibrillation following balloon mitral valvotomy: safety and efficacy of low-dose amiodarone.

BACKGROUND AND AIM OF THE STUDY: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia encountered in clinical practice. In developing countries, rheumatic mitral stenosis (MS) is the most frequent underlying condition in patients with AF. Sinus rhythm (SR) is difficult to achieve and maintain in these patients, but would be more easily achieved with reduction of left atrial pressure after successful balloon mitral valvotomy (BMV). METHODS: Eighty-five patients with persistent AF following BMV received amiodarone (600 mg once daily for two weeks, 200 mg daily thereafter). Electrical cardioversion was performed in those with persistent AF (at six and 12 weeks of drug therapy). RESULTS: Among patients, 33 (39%) converted with amiodarone alone. Of 52 patients who underwent cardioversion at six weeks, 41 (79%) converted to SR. Overall, 87% of patients converted to SR. None of the 11 patients with persistent AF could be converted to SR, despite a second attempt with direct current (DC) cardioversion at 12 weeks. Those who converted to SR had significantly shorter AF duration (AFD) (2.7+/-1.1 versus 3.2+/-0.7 years) and smaller left atrial (LA) size (50.0+/-7.7 versus 57.9+/-4.7 mm). Patient age, gender, NYHA class, ejection fraction and post-BMV variables were comparable between the two groups. Successful maintenance of SR was possible in 61/74 (82%) patients at a mean follow up of 30.6+/-7.1 months (range: 16-43 months). Again, mean AFD was shorter (1.8+/-0.6 versus 3.0+/-0.7 years) and LA size smaller (48.9+/-7.5 versus 54.7+/-6.9 mm) among those who maintained SR. However, even in patients with AFD > or =2 years, successful conversion and maintenance of SR was possible in 74% and 62% of patients, respectively. Among patients with LA size > or =60 mm (n = 16), the corresponding value were 84% and 77%, respectively. On multivariate analysis, only AFD was a predictor of acute and long-term success. The probability of SR remaining in those with AFD <2 years at 21, 30 and 43 months was 96%, 95% and 94.6%, respectively, while for those with AFD > or =2 years these values were 62%, 48% and 40%. CONCLUSION: Low-dose amiodarone was safe and effective in restoring and maintaining SR in patients with AF and rheumatic heart disease.