Healthcare workers' knowledge and practice of the South African national tuberculosis management guidelines

BACKGROUND

Tuberculosis (TB) remains a global public health concern. The 2014 South African (SA) national TB management guidelines were developed to decrease the burden of TB, but implementation remains a challenge.

OBJECTIVES

 To estimate healthcare workers' level of knowledge about the national TB management guidelines and to assess the implementation of these guidelines.

METHODS

A cross-sectional descriptive study was conducted in four randomly selected health facilities in Dr Kenneth Kaunda district, North West Province, SA. We administered a TB knowledge questionnaire and reviewed TB registers and 204 patient files.

RESULTS

 A total of 38 participants completed the TB knowledge questionnaire. The majority were professional nurses (89%). The participants' mean (standard deviation) age was 46 (8) years, and the median (interquartile range) career length was 10 (8 - 17) years. Inadequate knowledge of the national TB management guidelines was revealed in 12 participants (32%). The review of the TB register showed that 163 153 patients were screened for TB. Of these, 9 308 (6%) had presumptive TB, 8 116 (87%) had an Xpert test and 1 292 (16%) had positive Xpert results. Overall, 1 150 (12%) of the patients with presumptive TB were diagnosed with drug-sensitive TB and started treatment based on laboratory results and a clinical diagnosis. Of this sample, 999 patients (87%) were treated successfully. The patient file review showed that a total of 197 patients (97%) received the correct treatment dose according to body weight and treatment phase. Smear microscopy was consistently done throughout the intensive and continuation phases of TB treatment. Body weight was monitored in 199 patients (98%). Contact investigation was conducted for 133 patients (65%), and there was evidence that child contacts aged <5 years were started on isoniazid preventive therapy. Only 110 patients (54%) had documented HIV status. Of these, 66 (60%) were HIV positive, and 39 (59%) of them received antiretroviral therapy. Body mass index was monitored in 55 patients (27%). Eighty (39%) of the patients with TB were women of childbearing potential, and only 8 (10%) of them had their pregnancy test results recorded. Treatment side-effects were reported in 17 patient files (8%); 13 (76%) were managed and 8 (62%) had resolved side-effects.

CONCLUSION

Most participants had adequate knowledge of the national TB management guidelines. A high TB treatment success rate was noted, along with some good practices. The study also highlights several knowledge and practice gaps that can be overcome by measures such as quality audits to improve record keeping. Adequate training of healthcare workers, sustaining and updating knowledge through continuous training, and strengthened supervision mechanisms to ensure compliance with the guidelines are recommended.

Machine learning based risk stratification of patients undergoing ventricular tachycardia ablation

Background

Monomorphic ventricular tachycardia (VT) is a potentially life-threatening condition. Although radiofrequency catheter ablation represents an effective treatment method for many of these patients, significant variability is observed in postprocedural mortality, which is attributable to multiple factors, including the high burden of comorbidities. Therefore, there is a great demand for an accurate risk stratification system.

Purpose

We sought to implement a machine learning pipeline to predict 1-year all-cause mortality in patients undergoing VT ablation.

Methods

For 265 consecutive patients who underwent VT ablation at our center, we retrospectively collected demographics, medical history, cardiovascular risk factors, laboratory results, echocardiographic measurements, and VT ablation-related parameters. To predict 1-year all-cause mortality based on these features, several supervised machine learning models were trained and evaluated using 5-fold cross-validation. We applied a recursive elimination technique to identify the optimal subset of input features. The area under the receiver operating characteristic curve (AUC) with a 95% confidence interval (CI) was calculated to quantify the models' performance. We also identified the most important predictors of mortality using Shapley values. As the final step, we used topological data analysis to discern and visualize patient subgroups with different mortality risk.

Results

57 (22%) patients died during the 1-year follow-up period. In predicting all-cause mortality, the best performance was achieved by a random forest model utilizing 18 input features [AUC: 0.73 (95% CI: 0.68–0.78)]. This model significantly outperformed other previously published risk scores such as the I-VT [AUC: 0.63 (95% CI: 0.55–0.70), p&lt;0.001 vs. random forest] or the PAINESD [AUC: 0.63 (95% CI: 0.55–0.71), p=0.009 vs. random forest]. The most important predictors of mortality were mitral E-wave deceleration time, cardiac resynchronization therapy, age, electrical storm, and hemoglobin concentration. In the topological network created based on the 18 input features of the best-performing random forest model, we could identify five patient subsets with different clinical characteristics and 1-year mortality rates (Figure 1).

Conclusions

Our machine learning model could efficiently predict 1-year all-cause mortality in patients undergoing VT ablation. Thus, it could facilitate the prompt identification of high-risk patients and the personalization of treatment and follow-up strategies, ultimately leading to improved outcomes.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart Program, as part of the National Research, Development and Innovation Fund of HungaryThematic Excellence Programme of the Ministry for Innovation and Technology in Hungary

Impact of high-power and very high-power short-duration radiofrequency ablation on procedure characteristics and first-pass isolation during pulmonary vein isolation

Introduction

High-power short-duration (HPSD) radiofrequency ablation has been proposed as a method for producing rapid and effective lesions for pulmonary vein isolation (PVI). We aimed to evaluate the procedural characteristics and the first-pass isolation (FPI) rate of HPSD and very high-power short-duration (vHPSD) ablation compared to low-power long-duration (LPLD) ablation technique.

Methods

156 patients with atrial fibrillation (AF) were enrolled and assigned to LPLD, HPSD, or vHPSD PVI. The energy setting was 30W, 50W, and 90W in the LPLD, HPSD, and vHPSD groups, respectively.

Results

Bilateral PVI was achieved in all cases. The procedure time was 85 [75–101] min, 79 [65–91] min, and 70 [53–83] min in the LPLD, HPSD, and vHPSD groups, respectively (p&lt;0.0001). Left atrial (LA) dwelling times were also decreased significantly with the increase of RF energy (61 [55–70] min, 53 [41–56] min, and 45 [34–52] min, in the LPLD, HPSD, and vHPSD groups, respectively, p&lt;0.0001). The total RF ablation time was 1567 [1366–1761] sec, 1398 [1021–1711] sec, and 336 [247–386] sec in the LPLD, HPSD, and vHPSD group, respectively (p&lt;0.0001). The bilateral FPI rate was 57%, 78%, and 80% in the LPLD, HPSD, and vHPSD groups, respectively (p=0.0097). On the left side, FPI was achieved in 66% in the LPLD, 92% in the HPSD, and 85% in the vHPSD ablation group (p=0.0015). FPI on the right side was achieved in 72% in the LPLD, 88% in the HPSD, and 88% in the vHPSD ablation group (p=0.0188). The univariate analysis revealed that the use of HPSD (both sides: OR=2.72, 95% CI 1.15–6.44, p=0.023; right side: OR=2.90, 95% CI 1.02–8.20, p=0.045; left side: OR=5.91, 95% CI 1.84–19.04, p=0.003) and vHPSD (both sides: OR=2.90, 95% CI 1.24–6.44, p=0.014; right side: OR=3.09, 95% CI 1.09–8.74, p=0.045; left side: OR=2.89, 95% CI 1.13–7.43, p=0.027) ablation techniques were associated with a higher probability of FPI. The mid-term arrhythmia-free survival was similarly high in all three groups.

Conclusion

Our prospective, observational cohort study showed that both HPSD and vHPSD RF ablation is effective, as it shortens procedure time and RF time and results in a higher rate of FPI compared to LPLD ablation. Moreover, the mid-term arrhythmia-free survival was similarly high in all three groups. In our study, no safety concerns were raised for HPSD or vHPSD ablation.

Funding Acknowledgement

Type of funding sources: None.

Factors predicting repeated ablation in ventricular tachycardia patients

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart Program

Background

Catheter ablation has emerged to be the principal treatment for recurrent ventricular tachycardia (VT). Previously, several predictors of VT recurrence have been described, such as LVESD, severe MR, incessant VT, ICD shocks and elevated LDH levels. However, factors predicting an additional ablation are unknown.

Purpose

We aimed to establish predictors of repeat ablation and compare to the predictors of ventricular arrhythmia recurrence during 1-year follow-up in structural heart disease.

Methods

Baseline medical history, laboratory results, imaging parameters, clinical properties of VTs, and procedural data were gathered in a structured database.

Results

Out of the 272 patients, 96 (35%) experienced recurrence and 36 (13%) had repeated procedures within 1 year. Independent predictors of recurrence were left ventricular end systolic diameter (HR = 1.516, p=0.015), severe mitral regurgitation (HR = 2.446, p = 0.002), incessant VT (HR = 1.64, p = 0.02), VT inducibility (HR = 3.71, p = 0.003), ICD shocks (HR = 1.95, p = 0.002) and elevated LDH levels (HR = 1.26, p = 0.003). Regarding redo ablation, elevated LDH level (HR = 1.64, p = 0.01), incessant VT (HR = 2.94, p &lt; 0.001), ICD shocks (HR = 2.38, p = 0.02), only exit point ablation (HR = 2.14, p = 0.023) were independent predictors, while hypertension (HR = 0.32, p = 0.03), longer transmitral E-wave deceleration time (HR = 0.47, p = 0.04), substrate modification (HR = 0.47, p = 0.044) were protective.

Conclusion

Predictors of repeat ablation overlap only partially with those of VT recurrence. Predictors implying higher risk VT episodes predict both recurrence and repeat ablation while factors associated with more severe left ventricular systolic dysfunction predict recurrence but not a redo procedure.

Impact of high-power and very high-power short-duration radiofrequency ablation on procedure characteristics and first-pass isolation during pulmonary vein isolation

Funding Acknowledgements

Type of funding sources: None.

Introduction

High-power short-duration (HPSD) radiofrequency ablation has been proposed as a method for producing rapid and effective lesions for pulmonary vein isolation.We aimed to evaluate the procedural characteristics and the FPI rate of HPSD and very high-power short-duration (vHPSD) compared to low-power long-duration (LPLD) ablation techniques.

Methods

156 patients with atrial fibrillation (AF) were enrolled and assigned to LPLD, HPSD, or vHPSD PVI. The energy setting was 30W, 50W, and 90W in the LPLD, HPSD, and vHPSD groups, respectively.

Results

Bilateral PVI was achieved in all cases. The procedure time was 85 [75-101] min, 79 [65-91] min, and 70 [53-83] min in the LPLD, HPSD, and vHPSD groups, respectively (p&lt;0,0001). LA dwelling times were also decreased significantly with the increase of RF energy (61 [55-70] min, 53 [41-56] min, and 45 [34-52] min, in the LPLD, HPSD, and vHPSD groups, respectively, p&lt;0.0001). The total RF ablation time was 1398 [1021-1711] sec, 1567 (1366-1761) sec, and 336 [247-386] sec in the LPLP, HPSD, and vHPSD group, respectively ( p&lt;0,0001). Bilateral FPI was rate was 57%, 78% and 80% in the LPLD, HPSD, and vHPSD groups, respectively (p=0,0097). On the left side, FPI was achieved in 66% in the LPLD, in 92% in the HPSD, and in 85% in the vHPSD ablation group (p=0.0015). FPI on the right side was achieved in 72% in the LPLD, in 88% in the HPSD, and in 88% in the vHPSD ablation group (p=0,0188). FPI rates were significantly higher in the HPSD group compared to the LPLD group: both sided FPI rate was 57% vs. 78% (p=0.021), left sided FPI rate was 66% vs. 92% (p=0.0015), and right sided FPI rate was 72% vs. 88% (p=0.0401). Further increase in the RF power did not result in a significant additional increase in the FPI rate. In the HPSD vs. vHPSD group both sided FPI rate was 78% vs. 80% (p=0,8080), left sided FPI rate was 92% vs. 85% (p= 0,5275), and right sided FPI rate was 88% vs. 88% (p= 0,7561). Univariate analysis revealed that the use of HPSD ablation technique is associated with a higher probability of FPI (both sides: OR=2.72, 95% CI 1.15-6.44, p=0.023; right side: OR=2.90, 95% CI 1.02-8.20, p=0.045; left side: OR=5.91, 95% CI 1.84-19.04, p=0.003). The mid-term arrhythmia-free survival was similarly high in all three groups.

Conclusion

Our prospective, observational cohort study showed that both HPSD and vHPSD RF ablation is effective, as it shortens procedure time and RF time and results in a higher rate of FPI compared to LPLD ablation. Moreover, the mid-term arrhythmia-free survival was similarly high in all three groups. In our study, no safety concerns were raised due to HPSD ablation.

Size of transcatheter patent foramen ovale closure device affects atrial function

Funding Acknowledgements

Type of funding sources: None.

Introduction

Interatrial communications such as patent foramen ovale (PFO) are common abnormalities. For most people they are accidental findings; however, in some cases lead to paradoxical embolization. Transcatheter closure of PFO in patients with cryptogenic stroke is associated with reduced rates of recurrent stroke. The size of closure device is established according to anatomical features of atria. However, the impact of atrial septal closure on atrial remodelling is less known.

Methods

We prospectively enrolled 108 patients with cryptogenic ischemic stroke and PFO eligible for transcatheter PFO closure. Thirty-three patients had 6 month clinical follow-up examinations (mean age 46 ± 13 years, 34% females). National Institute of Health Stroke Score (NIHSS) was calculated as marker of clinical severity of the index stroke. Presence of any shunt, atrial volumes and functional parameters were evaluated including left atrial (LA) reservoir, conduit and contraction function before PFO closure and 6 months after procedure. Beyond conventional transthoracic echocardiography (Philips Epiq CVx Ultrasound), two dimensional speckle tracking method was used to assess body surface area-indexed LA maximal volume (LAVmaxi), LA minimal volume (LAVmini), LA volume before left atrial contraction (LApreAi), LA ejection fraction (LAEF), LA reservoir strain (LASres), LA conduit strain (LAScond), LA contraction strain (LAScontr), LA peak systolic strain rates (LASRs), LA peak early diastolic strain rate (LASRe) and LA peak late diastolic strain rate (LASRa) using dedicated software on separate workstation (Cardiac Performance; TomTec Imaging, Unterschleissheim, Germany). Zero reference point was set at the onset of QRS wave.

Results

The index stroke was modest and non-disabling, with an NIHSS 3.2 ± 2.6. Baseline LA volumes and functions were in normal range (LAVi 27.4 ± 10.3 ml/m2; LASres 46.85 ± 19.6 %; LAScond 25.6 ± 15.4%; LAScontr 21.35 ± 12.15 %; LASRa -1.9 ± 0.77 s-1). The 6 month clinical follow-up examinations revealed no significant differences (all p values &gt;0.05) in atrial volumes and strain parameters. However, LASRa was significantly lower (-1.4 ± 0.82 s-1, p = 0.01). Closure device size (25mm vs 30mm) and smoking proved to be independent predictors of 25% decrease of LASRa (p = 0.06, p = 0.03, respectively). No new cerebral ischaemic events, aortic erosions, atrial fibrillation, significant residual shunts or device thrombosis and displacement were recorded during the follow-up. 

Conclusion

PFO-associated strokes in young and middle-aged individuals are mainly non-disabling. Transcatheter interatrial closure was safe and effective in our study without promoting unfavourable anatomical atrial remodelling during short-term follow-up, however, it may affect active atrial contraction. Smoking and larger devices may decrease the rate of atrial deformation at short-term follow-up. Shorter PFO occluders are preferable in case of anatomical applicability.

Venous thromboembolic disease in adults admitted to hospital in a setting with a high burden of HIV and TB

BACKGROUND

HIV and tuberculosis (TB) independently cause an increased risk for venous thromboembolic disease (VTE): deep vein thrombosis (DVT) and/or pulmonary embolism (PE). Data from high HIV and TB burden settings describing VTE are scarce. The Wells' DVT and PE scores are widely used but their utility in these settings has not been reported on extensively.

OBJECTIVES

To evaluate new onset VTE, compare clinical characteristics by HIV status, and the presence or absence of TB disease in our setting. We also calculate the Wells' score for all patients.

METHODS

A prospective cohort of adult in-patients with radiologically confirmed VTE were recruited into the study between September 2015 and May 2016. Demographics, presence of TB, HIV status, duration of treatment, CD4 count, viral load, VTE risk factors, and parameters to calculate the Wells' score were collected.

RESULTS

We recruited 100 patients. Most of the patients were HIV-infected (n=59), 39 had TB disease and 32 were HIV/TB co-infected. Most of the patients had DVT only (n=83); 11 had PE, and 6 had both DVT and PE. More than a third of patients on antiretroviral treatment (ART) (43%; n=18/42) were on treatment for <6 months. Half of the patients (51%; n=20/39) were on TB treatment for <1 month. The median (interquartile range (IQR)) DVT and PE Wells' score in all sub-groups was 3.0 (1.0 - 4.0) and 3.0 (2.5 - 4.5), respectively.

CONCLUSION

HIV/TB co-infection appears to confer a risk for VTE, especially early after initiation of ART and/or TB treatment, and therefore requires careful monitoring for VTE and early initiation of thrombo-prophylaxis.

Structural and functional atrial remodelling after transcatheter closure of patent foramen ovale

Introduction

Patent foramen ovale (PFO) is a common abnormality affecting more than 20% of the adult population. For most people they are accidental findings; however, in some the PFO can open widely enabling paradoxical embolisation. Randomised controlled trials have demonstrated in patients with cryptogenic stroke that transcatheter closure of PFO with a septal occluder device is associated with reduced rates of recurrent stroke. However, the impact of atrial septal closure on left atrial (LA) and right atrial (RA) structural and functional remodelling is less known.

Methods

We prospectively enrolled 53 patients with cryptogenic ischemic stroke and PFO eligible for transcatheter PFO closure (mean age 46±11 years, 44% females). National Institute of Health Stroke Score (NIHSS), and the modified Rankin score (mRS) were calculated as markers of clinical severity of the index stroke. Presence of any shunt, atrial volumes and functional parameters were evaluated including LA reservoir, conduit and contraction function before PFO closure and 12 months after procedure. Beyond conventional transthoracic echocardiography (Philips Epiq CVx Ultrasound), two dimensional speckle tracking method was used to assess body surface area-indexed LA maximal volume (LAVmaxi), LA minimal volume (LAVmini), LA volume before left atrial contraction (LApreAi), LA ejection fraction (LAEF), LA reservoir strain (LASres), LA conduit strain (LAScond), LA contraction strain (LAScontr), LA peak systolic strain rates (LASRs), LA peak early diastolic strain rate (LASRe) and LA peak late diastolic strain rate (LASRa) using dedicated software on separate workstation (Cardiac Performance; TomTec Imaging, Unterschleissheim, Germany).

Results

The index stroke was modest and non-disabling, with an NIHSS 3.37±2.63 and mRS 1.67±1.06. Baseline LA, RA volumes and dimensions were in normal range (LAVi 25.5±9.6 ml/m2; LA length 37.6±6.2 mm; LA width 40.4±7.1 mm; RA length 36.6±6.7 mm; RA width 39.5±8.6 mm). Thirty-seven patient had 12 month clinical follow-up examinations revealing no significant differences (all p values &gt;0.05) in atrial volumes, ejection fraction and strain parameters. LASRa was significantly lower after 12 month (p=0.03; baseline LASRa −1.7±0.7 s–1 vs follow-up LASRa −1.3±0.9 s–1) No new cerebral ischaemic events, aortic erosions, atrial fibrillation, significant residual shunts or device thrombosis and displacement were recorded during the follow-up.

Conclusion

PFO-associated strokes in young individuals are mainly non-disabling. Our study suggests that transcatheter interatrial closure is effective without promoting unfavourable atrial anatomical remodelling during short-term follow-up, however, it may affect active atrial contraction. Long-term follow-up examinations are needed to investigate the potential late impact of occluders on atrial anatomical, functional remodelling.

Funding Acknowledgement

Type of funding source: None

A Simple Scale for Screening Lower-Extremity Arterial Disease as a Possible Cause of Low Back Pain: a Cross-sectional Study Among 542 Subjects

BACKGROUND

Epidemiological, imaging, and anatomical studies suggest an association between proximal arterial atherosclerosis and development of low back pain (LBP).

OBJECTIVES

We aimed to define (1) the frequency and (2) factors associated with exercise-induced proximal ischemia (EIPI) in individuals with LBP and (3) develop a clinical screening scale.

DESIGN

Monocentric cross-sectional study.

PARTICIPANTS

All patients with history of ongoing LBP referred to our exercise investigation laboratory for exercise transcutaneous oximetry (ex-tcPO₂) between January 2011 and December 2017 (n = 542; mean age, 65.4 ± 10.9; 83.9% men).

MAIN MEASURES

EIPI was defined as a decrease from rest of oxygen pressure (DROP) below - 15 mmHg on the lumbar and/or buttock probes. Ex-tcPO₂ is a reliable validated tool for diagnosing EIPI in comparison with arteriography and computed tomography angiography. Ex-tcPO₂ was performed on a treadmill until symptom manifestation or exhaustion. Clinical data were collected using interview questionnaires, medical file review, and clinical examination.

KEY RESULTS

EIPI was diagnosed in 282 patients (52%). Age ≤ 70 years (OR, 2.22; 95% CI, 1.35-3.57; p = 0.002), a history of proximal revascularization (OR, 2.64; 95% CI, 1.50-4.65; p = 0.001), use of antiplatelet medication (OR, 1.71; 95% CI, 0.96-3.06; p = 0.069), a relationship between exercise and LBP (OR, 2.61; 95% CI, 1.49-4.57; p = 0.001), and an abnormal ankle to brachial index (OR, 2.87; 95% CI, 1.77-4.66; p < 0.0001) were identified as EIPI predictors. Using these items, we developed a screening scale that showed an area under the receiver operating characteristics curve of .756. At a score of ≥ 3, the sensitivity, specificity, and accuracy for EIPI were 84%, 55%, and 71%, respectively.

CONCLUSIONS

EIPI was common among our patients with LBP undergoing ex-TcPO₂. Our screening scale could help better select the patients who require angiography.

Mitochondrial pathway of apoptosis and necrosis contribute to tenofovir disoproxil fumarate-induced renal damage in rats

Tenofovir disoproxil fumarate (TDF) is currently the only nucleotide analogue reverse-transcriptase inhibitor that is approved by the Food and Drug administration (FDA), USA, for the treatment of human immunodeficiency virus (HIV) infection. In recent days, renal toxicity is becoming common i HIV patients treated with TDF. However, the mechanism of tenofovir nephrotoxicity is not clear. We hypothesized that mitochondrial pathway of apoptosis, poly [ADP-ribose] polymerase (PARP) overactivation and neutrophil infiltration may contribute to tenofovir-induced renal damage. Renal damage was induced in adult male Wistar rats by the oral administration of 600 mg/kg body weight daily for five consecutive weeks. Kidneys were removed and used for histological and biochemical analyses. Apoptosis was detected by terminal deoxynucleotidyl transferase biotin-deoxyuridine triphosphate nick end-labelling (TUNEL) assay and caspase 3 activity and protein expression; mitochondrial pathway of apoptosis by cyt c release; and PARP activation by immunofluorescence, immunohistochemistry and Western blot techniques. Myeloperoxidase (MPO) activity was measured as a marker of neutrophil infiltration. TDF administration resulted in increased number of TUNEL-positive cells, activation of caspase 3 and release of cyt c from mitochondria into the cytosol in the kidneys. There was increased nuclear localization of PARP as well as increase in its protein level in the TDF-treated rat kidneys. In addition, renal MPO activity was increased ninefold as compared to controls. The results of the present study show that mitochondrial apoptotic pathway, PARP overactivation and neutrophil infiltration contribute to tenofovir-induced renal damage in rats.

Post-exercise ankle blood pressure and ankle to brachial index after heavy load bicycle exercise

The American Heart Association (AHA) recommendations for diagnosing peripheral artery disease (PAD) after exercise are a decrease >20% of ankle brachial index (ABI) or >30 mm Hg of ankle systolic blood pressure (ASBP) from resting values. We evaluated ABI and ASBP values during incremental maximal exercise in physically active and asymptomatic patients. Patients (n = 726) underwent incremental bicycle tests with pre- and post-exercise recording of all four limbs arterial pressures simultaneously. Univariate and multivariate analyses were performed to define the correlation between post-exercise ABI with various clinical factors, including age. Thereafter, the population was divided into groups of age: less than 40 (G < 40), from 40 to 44 (G40/44) from 45 to 49 (G45/49), from 50 to 54 (G50/54), from 55 to 59 (G55/59), from 60 to 64 (G60/64), and 65 and above (G ≥ 65) years. Results are mean ± SD. * is two-tailed P < .05 for ANOVA with Dunnett's post-hoc test from G40. Changes from rest in ASBP were -3 ± 22 (G < 40), -2 ± 20 (G40/44), 4 ± 22* (G45/49), 10 ± 25* (G50/54), 18 ± 21* (G55/59), 23 ± 27* (G60/64), and 16 ± 22* (G ≥ 65) mm Hg. Decreases from rest in ABI were 32 ± 9 (G < 40), 33 ± 9 (G40/44), 29 ± 8 (G45/49), 27 ± 10* (G50/54), 24 ± 7* (G55/59), 22 ± 12* (G60/64), and 21 ± 12* (G ≥ 65) % of resting ABI. Maximal incremental exercise results in ABI and ASBP changes are mostly dependent on age. The AHA limits for post-exercise ABI are inadequate following maximal incremental bicycle testing. Future studies detecting PAD in active patients should account for the effect of age.

Mitochondrial complex I defect resulting from exercise-induced lower limb ischemia in patients with peripheral arterial disease

This study aims to compare the structural and mitochondrial alterations between muscle segments affected by exercise-induced ischemia and segments of the same muscle without ischemia, in the same subject. In a prospective analysis, 34 patients presenting either peripheral arterial disease or chronic coronary syndrome without any evidence of peripheral arterial disease were eligible for inclusion based on findings indicating a need for either a femoro-popliteal bypass or a saphenous harvesting for coronary bypass. Before surgery, we assessed the level of exercise-induced ischemia in proximal and distal sections of the thigh by the measurement of transcutaneous oxygen pressure during an exercise treadmill test. Distal and proximal biopsies of the sartorius muscle were procured during vascular surgical procedures to assess mitochondrial function and morphometric parameters of the sartorius myofibers. Comparisons were made between the distal and proximal biopsies, with respect to these parameters. Thirteen of the study patients that initially presented with peripheral arterial disease had evidence of an isolated distal thigh exercise-induced ischemia, associated with a 35% decrease in the mitochondrial complex I enzymatic activity in the distal muscle biopsy. This defect was also associated with a decreased expression of the manganese superoxide dismutase enzyme and with alterations of the shapes of the myofibers. No functional or structural alterations were observed in the patients with coronary syndrome. We validated a specific model ischemia in peripheral arterial disease characterized by muscular alterations. This "Distal-Proximal-Sartorius Model" would be promising to explore the physiopathological consequences specific to chronic ischemia. NEW & NOTEWORTHY We compared proximal versus distal biopsies of the sartorius muscle in patients with superficial femoral artery stenosis or occlusion and proof of, distal only, regional blood flow impairment with exercise oximetry. We identified a decrease in the mitochondrial complex I enzymatic activity and antioxidant system impairment at the distal level only. We validate a model to explore the physiopathological consequences of chronic muscle ischemia.

Neurovascular microcirculatory vasodilation mediated by C-fibers and Transient receptor potential vanilloid-type-1 channels (TRPV 1) is impaired in type 1 diabetes

Microvascular dysfunction may have an early onset in type 1 diabetes (T1D) and can precede major complications. Our objectives were to assess the endothelial-dependent (acetylcholine, ACh; and post-occlusive hyperemia, PORH), non-endothelial-dependent (sodium nitroprusside, SNP) and neurovascular-dependent (local heating, LH and current induced vasodilation, CIV) microcirculatory vasodilation in T1D patients compared with matched control subjects using a laser speckle contrast imager. Seventeen T1D patients - matched with 17 subjects according to age, gender, Body-Mass-Index, and smoking status - underwent macro- and microvascular investigations. The LH early peak assessed the transient receptor potential vanilloid type 1 channels (TRPV1) mediated vasodilation, whereas the plateau assessed the Nitirc-Oxyde (NO) and endothelium-derived hyperpolarizing factor (EDHF) pathways. PORH explored sensory nerves and (EDHF), while CIV assessed sensory nerves (C-fibers) and prostaglandin-mediated vasodilation. Using neurological investigations, we observed that C-fiber and A-delta fiber functions in T1D patients were similar to control subjects. PORH, CIV, LH peak and plateau vasodilations were significantly decreased in T1D patients compared to controls, whereas there was no difference between the two groups for ACh and SNP vasodilations. Neurovascular microcirculatory vasodilations (C-fibers and TRPV 1-mediated vasodilations) are impaired in TD1 patients whereas no abnormalities were found using clinical neurological investigations. Clinicaltrials: No. NCT02538120.

Aging effect on microcirculation: A multiscale entropy approach on laser speckle contrast images

PURPOSE

It has long been known that age plays a crucial role in the deterioration of microvessels. The assessment of such deteriorations can be achieved by monitoring microvascular blood flow. Laser speckle contrast imaging (LSCI) is a powerful optical imaging tool that provides two-dimensional information on microvascular blood flow. The technique has recently been commercialized, and hence, few works discuss the postacquisition processing of laser speckle contrast images recorded in vivo. By applying entropy-based complexity measures to LSCI time series, we present herein the first attempt to study the effect of aging on microcirculation by measuring the complexity of microvascular signals over multiple time scales.

METHODS

Forearm skin microvascular blood flow was studied with LSCI in 18 healthy subjects. The subjects were subdivided into two age groups: younger (20-30 years old, n = 9) and older (50-68 years old, n = 9). To estimate age-dependent changes in microvascular blood flow, we applied three entropy-based complexity algorithms to LSCI time series.

RESULTS

The application of entropy-based complexity algorithms to LSCI time series can differentiate younger from older groups: the data fluctuations in the younger group have a significantly higher complexity than those obtained from the older group.

CONCLUSIONS

The effect of aging on microcirculation can be estimated by using entropy-based complexity algorithms to LSCI time series.

Spectrum of Factors Triggering Endothelial Dysfunction in PIH

INTRODUCTION

Pre-eclampsia (PE) is a major cause of maternal and fetal/neonatal mortality and morbidity. The aetiology and pathogenesis of PE is yet to be completely understood. Evidence shows that, Endothelial Dysfunction (ED) plays a pivotal role in the genesis of this multi-system disorder that develops in PE and eclampsia.

AIM

To determine the circulating levels of factors Malondialdehyde (MDA), Ferric Reducing Ability of Plasma-α (FRAP), Tumour Necrosis Factor (TNF-α), sFlt-1, VEGF, PlGF, Nitric Oxide (NO) that influence the ED.

MATERIALS AND METHODS

Study groups consisted of Normotensive pregnant women (N), preeclamptic women (PE) and eclamptic women (E) with 100 subjects in each group in the 3^rd trimester of pregnancy. They were investigated for MDA, FRAP, TNF-α, sFlt-1, VEGF, PlGF, NO. Statistical analysis was done using Analysis of Variance (ANOVA).

RESULTS

When compared to controls MDA, TNF-α, sFlt-1 levels were found to be significantly high and FRAP, VEGF, PIGF and NO levels were significantly low in PE and E group. E showed a significantly high level of MDA, TNF-α, sFlt-1 and low levels of FRAP, VEGF, PIGF, NO when compared to PE group.

CONCLUSION

Our study substantiated the fact, that oxidative stress, imbalance between anti-angiogenic factors and pro- angiogenic factors exists in Pregnancy Induced Hypertension (PIH) condition. This imbalance is directly related to the ED, the hallmark of PE. So oxidative stress, VEGF, PlGF and sFlt-1 can be used as markers to analyze the onset and progression of the disease.

Predicting groundwater redox status on a regional scale using linear discriminant analysis

Reducing conditions are necessary for denitrification, thus the groundwater redox status can be used to identify subsurface zones where potentially significant nitrate reduction can occur. Groundwater chemistry in two contrasting regions of New Zealand was classified with respect to redox status and related to mappable factors, such as geology, topography and soil characteristics using discriminant analysis. Redox assignment was carried out for water sampled from 568 and 2223 wells in the Waikato and Canterbury regions, respectively. For the Waikato region 64% of wells sampled indicated oxic conditions in the water; 18% indicated reduced conditions and 18% had attributes indicating both reducing and oxic conditions termed "mixed". In Canterbury 84% of wells indicated oxic conditions; 10% were mixed; and only 5% indicated reduced conditions. The analysis was performed over three different well depths, <25m, 25 to 100 and >100m. For both regions, the percentage of oxidised groundwater decreased with increasing well depth. Linear discriminant analysis was used to develop models to differentiate between the three redox states. Models were derived for each depth and region using 67% of the data, and then subsequently validated on the remaining 33%. The average agreement between predicted and measured redox status was 63% and 70% for the Waikato and Canterbury regions, respectively. The models were incorporated into GIS and the prediction of redox status was extended over the whole region, excluding mountainous land. This knowledge improves spatial prediction of reduced groundwater zones, and therefore, when combined with groundwater flow paths, improves estimates of denitrification.

Association of interleukin-28B rs12979860 and rs8099917 polymorphisms with sustained viral response in hepatitis C virus genotype 1 and 3 infected patients from the Indian subcontinent

BACKGROUND

Polymorphisms of the IL28B gene (rs12979860 and rs8099917) have been shown to impact treatment responses in hepatitis C virus (HCV) infected patients. The association of these polymorphisms with sustained viral response (SVR) has been studied in HCV genotype 3 infected patients in India, but not in genotype 1.

OBJECTIVES

This study aimed to determine the association of IL28B gene polymorphisms and other host and viral factors with treatment response in patients with HCV genotype 1 and 3 infection.

MATERIALS AND METHODS

DNA from 42 HCV-infected patients on antiviral therapy was analysed for the IL28B polymorphisms using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Bidirectional sequencing was performed on a subset of samples for verification of PCR-RFLP results. Information on age, weight, height, diabetic status, pre-treatment viral load and alanine aminotransferase (ALT) levels was obtained from clinical records. The IL28B genotypes and the other factors were analysed for their association with SVR.

RESULTS

The frequency distribution of rs12979860 CC/CT/TT genotypes was found to be 66.7%, 26.2% and 7.1%, respectively. For rs8099917 genotype, the TT/GT/GG distribution was 73.8%, 21.4% and 4.8%, respectively. SVR was seen in 61.9% of cases (55.6% in genotype 1 and 62.5% in genotype 3). CC genotype at rs12979860 and TT genotype at rs8099917 were significantly higher in responders (P = 0.013 and 0.042, respectively). Lower baseline ALT and rapid viral response were also found to be associated with SVR. On logistic regression analysis, CC genotype at rs12979860 emerged as the most powerful predictor of treatment response.

CONCLUSION

IL28B polymorphisms are strong predictors of SVR in patients from the Indian subcontinent infected with HCV genotype 3 and genotype 1.

Characterization of hepatitis B virus surface antigen variability and impact on HBs antigen clearance under nucleos(t)ide analogue therapy

For hepatitis B virus (HBV)-related chronic infection under treatment by nucleos(t)ide analogues (NUCs), HBsAg clearance is the ultimate therapeutic goal but very infrequent. We investigated how HBV envelope protein variability could lead to differential HBsAg clearance on NUCs. For 12 HBV genotype D patients receiving NUCs, six resolvers (HBsAg clearance) were compared to six matched nonresolvers (HBsAg persistence). PreS/S amino acid (aa) sequences were analysed with bioinformatics to predict HBV envelope antigenicity and aa covariance. To enrich our analyses on very rare resolvers, these were compared with other HBV genotype D strains in three characterized clinical cohorts including common chronically infected patients. The sT125M+sP127T combination was observed in four nonresolvers of six, corroborated by aa covariance analysis, associated with a lower predicted antigenicity than sT125T+sP127P. Concordant features within this HBV key functional domain, at positions 125 and 127, were reported from two of the three comparative cohorts. In our hands, a lower ELISA reactivity of HBV-vaccinated mice sera was observed against the sT125M mutant. In the S gene, 56 aa changes in minor variants were detected in non-resolvers, mainly in the major hydrophilic region, vs 28 aa changes in resolvers. Molecular features in patients showing HBsAg persistence on NUCs argue in favour of a different aa pattern in the HBV S gene compared to those showing HBsAg clearance. In nonresolvers, a decrease in HBs 'a' determinant antigenicity and more frequent mutations in the S gene suggest a role for the HBV envelope characteristics in HBsAg persistence.

Mother to child transmission of hepatitis B virus: a cause for concern

Mother to child transmission of hepatitis B virus (HBV) is an important public health issue. India introduced HBV vaccine in 10 states as part of its Universal Immunization Program (UIP). Here we show evidence of mother-to-child transmission of HBV in three families from Jharkhand and Bihar states where HBV vaccination is not yet included in the UIP. This report illustrates the need for active screening of HBV in pregnant women and implementation of HBV vaccine across all states in India to reduce the burden of disease.

Prevalence of non-responsiveness to an indigenous recombinant hepatitis B vaccine: a study among South Indian health care workers in a tertiary hospital

BACKGROUND AND AIM

Health care workers (HCW) are at higher risk of contracting HBV infection. Non-response to HBV vaccine is one of the major impediments to prevent healthcare associated HBV infection (HAHI). We estimated the prevalence of non-responsiveness to initial 3-dose regimen of an indigenous recombinant HBV vaccine (GeneVac-B) among South Indian HCWs and typed the HLA in non-responders.

STUDY DESIGN AND METHOD

Of the 778 subjects screened over 1 year, 454 completed all three doses of the hepatitis B vaccination. Anti-HBs titers were estimated by microparticle enzyme immunoassay AxSYM AUSAB, (Abbott, Germany). HLA typing was done using SSP-PCR assay AllSet+™ Gold SSP (Invitrogen, USA).

RESULTS

The overall seroconversion rate (anti-HBs>10 mIU/mL) was 98.89% wherein 90.8% had titers>1000mIU/mL, 7.6% had titers 100-1000mIU/mL, 0.43% had titers<100 mIU/mL and 1.1% were non-responsive (<10 mIU/mL) to the initial 3-dose regimen. Antibody titers<1000 mIU/mL were significantly associated with the highest quartile of body mass index (BMI) (P<0.001). We found no significant difference in seroprotection rate between gender (P=0.088). There was no difference in seroprotection rates among various ethnic groups (P=0.62). Subjects who were non-responsive in our study had at least one HLA allele earlier known to be associated with non-responsiveness to the vaccine.

CONCLUSION

Our findings suggest that non-response to HBV vaccine is not a major impediment to prevent HAHI. Robust seroprotection rates can be achieved using this indigenous HBV vaccine. However, gender and BMI might influence the level of anti-HBs titers. We recommend the use of this cost effective HBV vaccine as well as postvaccination anti-HBs testing to prevent HAHI among HCWs.

A Study on the Level of Oxidative Stress and Inflammatory Markers in Type 2 Diabetes Mellitus Patients with Different Treatment Modalities

INTRODUCTION

The prevalence of type 2 diabetes mellitus is increasing worldwide in all the age group. UKPDS study had shown that good glycaemic control is maintained by the administration of insulin in addition to hypoglycaemic drugs. But, hyperinsulinemia might cause vascular complications in T2DM. Oxidative stress and inflammation are common in diabetes and plays an important role in vascular complications.

AIM

The study has been designed to estimate and compare the level of oxidative stress and inflammation in type 2 diabetic patients under different treatment modalities.

MATERIALS AND METHODS

Sixty Type 2 diabetic subjects undergoing treatment were selected from Government Hospital and VMKV Medical College & Hospital at Salem. The subjects were divided into two groups based on treatment modalities, hypoglycaemic drugs subjects as Group-I (30) and hypoglycaemic drugs & Insulin subjects in Group-II (30). BMI was calculated by standard formula and Fasting blood sugar (FBS), postprandial blood sugar (PPBS), glycated haemoglobin (HbA1c), Lipid profile, oxidative stress (MDA) and inflammatory markers were measured by well established methods. SPSS 16.0 version was used for statistical analysis.

RESULT

In our study we have found significantly high levels of BMI, MDA and hsCRP (25.5±2.79, 2.73±1.65, 1.98±0.85) in Group II subjects when compared to Group I subjects (23.4±3.09, 2.23±1.76, 1.168±1.124).

CONCLUSION

Since risk factors like BMI, MDA and hsCRP were high in Diabetes mellitus patients on both oral hypoglycaemic drugs and insulin, they are more susceptible to cardiovascular diseases. Evaluation of these markers at regular interval can reduce the incidence of vascular complications in Type 2 DM patients.

Adefovir nephrotoxicity in a renal allograft recipient

Adefovir dipivoxil, an oral prodrug of adefovir, is used in the treatment of lamivudine-resistant hepatitis B virus (HBV) infection. Nephrotoxicity manifesting as proximal renal tubular dysfunction and acute tubular necrosis (ATN) were commonly reported in the past, when higher doses were used for the treatment of human immunodeficiency virus infection. However, nephrotoxicity is rare at lower doses that are currently recommended for the treatment of HBV infection. A 31-year-old female was detected to be hepatitis B surface antigen positive months after a kidney transplant. The patient was initiated on lamivudine, but developed resistance after 1 year of treatment, at which time low-dose adefovir was added. The patient developed renal allograft dysfunction after 10 months of starting adefovir. Serum creatinine increased from 1.1 mg/dl to 1.9 mg/dl, along with progressively increasing sub-nephrotic proteinuria. Renal allograft biopsy revealed features of ATN. After discontinuation of adefovir, proteinuria resolved and renal dysfunction improved slowly over the next 2 years. Adefovir-induced nephrotoxicity, although uncommon at lower doses, needs to be considered in the differential diagnosis of renal dysfunction and sub-nephrotic proteinuria occurring in patients receiving adefovir for prolonged periods.

Evidence for a vasomotor cyclo-oxygenase dependent mechanism of sensitization at the cutaneous level

AIMS

Current-induced vasodilation (CIV) is an axon-reflex response observed during monopolar current application such as iontophoresis. Cyclo-oxygenase derivates (COD) participate in CIV and act as sensitizing agents at the anodal level. Mechanisms involved during cathodal current application (CCA) are partially unknown. In a randomized double-blind crossover trial, we tested in 16 healthy subjects (i) the influence of the inter-stimulation interval (I-I) by comparing CIV following all-at-once 10 s CCA against 2 × 5 s CCA with intervals ranging from15 s-16 min and (ii) the participation of COD in CIV using 1 g aspirin or placebo intake.

METHODS

Measurements were repeated 2 h and 14 days after treatment. Laser Doppler flowmetry assessed cutaneous blood flow, reported in multiples of baseline.

RESULTS

Before treatment, peak vasodilation 10 min after the last current application (CVCstim2 ) increased compared with baseline whatever the I-I. Increase in CVCstim2 from baseline was greater for the 4 min (9.4 (5.3, 10.9) times; median (1(st) percentile, 3(rd) percentile)) and higher I-Is compared with all-at-once delivery (3.0 (2.1, 4.3) times, P < 0.05). The response was similar after placebo but aspirin abolished this vasodilation (increase by 1.2 (1.1, 1.3) times for all-at-once delivery and by 1.5 (1.3, 1.7) ± 0.3 times for 4 min interval, 2 h after aspirin intake) that recovered after 14 days.

CONCLUSIONS

This confirms the participation of COD in CIV with CCA and their sensitizing action. This model can represent an attractive way to study the axon-reflex and sensitizing function of COD in humans.

Genotypes of hepatitis C virus in the Indian sub-continent: a decade-long experience from a tertiary care hospital in South India

BACKGROUND

Hepatitis C virus (HCV) is a leading cause of chronic liver disease (CLD) that can progress to cirrhosis and hepatocellular carcinoma. Genotypes of HCV can vary in pathogenicity and can impact on treatment outcome.

OBJECTIVES

To study the different genotypes among patients with HCV related CLD attending a tertiary care hospital in south India during 2002-2012.

STUDY DESIGN

Study subjects were those referred to clinical virology from the liver clinic. Genotyping was performed using the genotype specific core primers in nested polymerase chain reaction (PCR), 5' non-coding regions based PCR- restriction fragment length polymorphism and NS5B sequencing methods. With the latter method, obtained sequences were compared with published GenBank sequences to determine the genotype.

RESULTS

Of the 451 samples tested, HCV genotype 3 was found to be the most predominant (63.85%). Other genotypes detected were genotype 1 (25.72%), genotype 2 (0.002%), genotype 4 (7.5%) and genotype 6 (2.7%). Genotype 3 was the common genotype in patients from Eastern India while genotype 1 and 4 were mainly seen in South Indian patients. Genotype 6 was seen exclusively in patients from North-Eastern India. Two other patients were infected with recombinants of genotype 1 and 2.

CONCLUSIONS

In this study spanning a decade, HCV genotype 3 and genotype 1 were found to be the predominant genotypes in the Indian sub-continent. Genotype 4 and genotype 6 appeared to show some geographic restriction. A continued monitoring of HCV genotypes is essential for the optimum management of these chronically infected patients. In addition, knowledge of circulating genotypes could impact on future vaccine formulations.

Earlier therapeutic effects associated with high dose (2.0 mg) Ranibizumab for treatment of vascularized pigment epithelial detachments in age-related macular degeneration

SUMMARY STATEMENT

Intravitreal high dose (2 mg) ranibizumab may lead to quicker resolution of choroidal neovascularization (CNV) and associated retinal pigment epithelial detachment in eyes with exudative age-related macular degeneration, although it may possibly correlate with RPE tears in certain cases.

PURPOSE

This prospective study compared the outcomes of 0.5 vs 2.0 mg intravitreal ranibizumab injections (RI) for treating vascularized pigment epithelial detachment (vPED) due to age-related macular degeneration.

METHODS

Patients with vPED were randomized to receive 2.0 vs 0.5 mg RI monthly for 12 months or for 4 months and then repeated on a pro-re nata basis. Optical coherence tomography, fundus photography, and fluorescein and indocyanine-green angiography were obtained at baseline and subsequent specific intervals. Outcome measures were best-corrected standardized visual acuities, central 1-mm thickness, surface area (SA), greatest linear diameter (GLD), heights (PED and CNV), and amount of subretinal fluid (SRF) and cystoid macular edema (CME).

RESULTS

Both groups yielded reductions of the central 1-mm thickness, PED and CNV SA and PED height and GLD, SRF, and CME. Vision improvement and reduction in SRF and PED height occurred earlier for eyes receiving the 2.0 mg dose. Cataract progression was similar but RPE tears developed more often with the 2.0 mg dose.

CONCLUSIONS

There were similar visual and anatomical outcomes at the end of the study; however, the higher dose yielded more rapid reductions and more complete resolution of the PED, although there was possible increased tendency for an RPE tear with the higher dose.

Antiviral efficacy of adefovir dipivoxil in the treatment of chronic hepatitis B subjects from Indian subcontinent

Adefovir is one of the therapeutic options for the treatment of chronic hepatitis B. A total of 30 adefovir-experienced subjects with the median treatment duration of 12 (interquartile range (IQR) 6-18) months were studied. Virological response was measured by hepatitis B virus deoxyribonucleic acid (HBV DNA) levels. HBV reverse transcriptase (rt) domains were sequenced for the identification of resistance mutations. Among the 30 subjects, two (7%) showed virological response and 19 (63%) were non-responders. The virological response for the remaining nine (30%) subjects was not determined. On sequence analysis, two subjects were identified with rtI169L and rtA181V mutation after 9 months and 18 months of adefovir treatment, respectively. Though the frequencies of adefovir resistance mutations are low, a large majority of subjects showed non-response. Therefore, adefovir in the management of HBV should be used judiciously.