Left Bundle Branch Pacing vs Left Ventricular Septal Pacing vs Biventricular Pacing for Cardiac Resynchronization Therapy

BACKGROUND

Left bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are considered to be acceptable as LBBAP strategies. Differences in clinical outcomes between LBBP and LVSP are yet to be determined.

OBJECTIVES

The purpose of this study was to compare the outcomes of LBBP vs LVSP vs BIVP for CRT.

METHODS

In this prospective multicenter observational study, LBBP was compared with LVSP and BIVP in patients undergoing CRT. The primary composite outcome was freedom from heart failure (HF)-related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, postprocedural NYHA functional class, and electrocardiographic and echocardiographic parameters.

RESULTS

A total of 415 patients were included (LBBP: n = 141; LVSP: n = 31; BIVP: n = 243), with a median follow-up of 399 days (Q1-Q3: 249.5-554.8 days). Freedom from the primary composite outcomes was 76.6% in the LBBP group and 48.4% in the LVSP group (HR: 1.37; 95% CI: 1.143-1.649; P = 0.001), driven by a 31.4% absolute increase in freedom from HF-related hospitalizations (83% vs 51.6%; HR: 3.55; 95% CI: 1.856-6.791; P < 0.001) without differences in all-cause mortality. LBBP was also associated with a higher freedom from the primary composite outcome compared with BIVP (HR: 1.43; 95% CI: 1.175-1.730; P < 0.001), with no difference between LVSP and BIVP.

CONCLUSIONS

In patients undergoing CRT, LBBP was associated with improved outcomes compared with LVSP and BIVP, while outcomes between BIVP and LVSP are similar.

Sustained Apnea for Epicardial Access With Right Ventriculography: The SAFER Epicardial Approach

BACKGROUND

Epicardial access (EA) has emerged as an increasingly important approach for the treatment of ventricular arrhythmias and to perform other interventional cardiology procedures. EA is frequently underutilized because the current approach is challenging and carries a high risk of life-threatening complications.

OBJECTIVE

The purpose of this study was to determine the efficacy and safety of the SAFER (Sustained Apnea for Epicardial Access With Right Ventriculography) epicardial approach.

METHODS

Consecutive patients who underwent EA with the SAFER technique were included in this multicenter study. The primary efficacy outcome was the successful achievement of EA. The primary safety outcomes included right ventricular (RV) perforation, major hemorrhagic pericardial effusion (HPE), and bleeding requiring surgical intervention. Secondary outcomes included procedural characteristics and any complications. Our results were compared with those from previous studies describing other EA techniques to assess differences in outcomes.

RESULTS

A total of 105 patients undergoing EA with the SAFER approach from June 2021 to February 2023 were included. EA was used for ventricular tachycardia ablation in 98 patients (93.4%), left atrial appendage closure in 6 patients (5.7%), and phrenic nerve displacement in 1 patient (0.9%). EA was successful in all subjects (100%). The median time to EA was 7 minutes (IQR: 5-14 minutes). No cases of RV perforation, HPE, or need of surgical intervention were observed in this cohort. Comparing our results with previous studies about EA, the SAFER epicardial approach resulted in a significant reduction in major pericardial bleeding.

CONCLUSIONS

The SAFER epicardial approach is a simple, efficient, effective, and low-cost technique easily reproducible across multiple centers. It is associated with lower complication rates than previously reported techniques for EA.

Performance of the REAL-AF Same-Day Discharge Protocol in Patients Undergoing Catheter Ablation of Atrial Fibrillation

BACKGROUND

Same-day discharge (SDD) after catheter ablation of atrial fibrillation (AF) has been widely adopted. Nevertheless, planned SDD has been performed by using subjective criteria rather than standardized protocols.

OBJECTIVES

The goal of this study was to determine the efficacy and safety of the previously described SDD protocol in a prospective multicenter study.

METHODS

Using the REAL-AF (Real-world Experience of Catheter Ablation for the Treatment of Paroxysmal and Persistent Atrial Fibrillation) SDD protocol eligibility criteria (stable anticoagulation, no bleeding history, left ventricular ejection fraction >40%, no pulmonary disease, no procedures within 60 days, and body mass index <35 kg/m2), operators prospectively determined whether patients undergoing ablation of AF were candidates for SDD (SDD vs non-SDD groups). Successful SDD was achieved if the patient met the protocol discharge criteria. The primary efficacy endpoint was the success rate of SDD. The primary safety endpoints were readmission rates as well as acute and subacute complications. The secondary endpoints included procedural characteristics and freedom from all-atrial arrhythmias.

RESULTS

A total of 2,332 patients were included. The REAL-AF SDD protocol identified 1,982 (85%) patients as potential candidates for SDD. The primary efficacy endpoint was achieved in 1,707 (86.1%) patients. The readmission rate for SDD vs non-SDD group was similar (0.8% vs 0.9%; P = 0.924). The SDD group had a lower acute complication rate than the non-SDD group (0.8% vs 2.9%; P < 0.001), and there was no difference in the subacute complication rate between groups (P = 0.513). Freedom from all-atrial arrhythmias was comparable between groups (P = 0.212).

CONCLUSIONS

In this large, multicenter prospective registry, the use of a standardized protocol showed the safety of SDD after catheter ablation of paroxysmal and persistent AF. (Real-world Experience of Catheter Ablation for the Treatment of Paroxysmal and Persistent Atrial Fibrillation [REAL-AF]; NCT04088071).

Association of lung recruitment and change in recruitment-to-inflation ratio from supine to prone position in acute respiratory distress syndrome

Prone positioning is an evidence-based treatment for patients with moderate-to-severe acute respiratory distress syndrome. Lung recruitment has been proposed as one of the mechanisms by which prone positioning reduces mortality in this group of patients. Recruitment-to-inflation ratio (R/I) is a method to measure potential for lung recruitment induced by a change in positive end-expiratory pressure (PEEP) on the ventilator. The association between R/I and potential for lung recruitment in supine and prone position has not been studied with computed tomography (CT) scan imaging. In this secondary analysis, we sought to investigate the correlation between R/I measured in supine and prone position with CT and the potential for lung recruitment as measured by CT scan. Among 23 patients, the median R/I did not significantly change from supine (1.9 IQR 1.6-2.6) to prone position (1.7 IQR 1.3-2.8) (paired t test p = 0.051) but the individual changes correlated with the different response to PEEP. In supine and in prone position, R/I significantly correlated with the proportion of lung tissue recruitment induced by the change of PEEP. Lung tissue recruitment induced by a change of PEEP from 5 to 15 cmH₂O was 16% (IQR 11-24%) in supine and 14.3% (IQR 8.4-22.6%) in prone position, as measured by CT scan analysis (paired t test p = 0.56). In this analysis, PEEP-induced recruitability as measured by R/I correlated with PEEP-induced lung recruitment as measured by CT scan, and could help to readjust PEEP in prone position.

Global Longitudinal Strain Is Associated with Mortality in Patients with Multiple Myeloma

Patients with multiple myeloma (MM) are at a high risk for developing cardiovascular complications. Global longitudinal strain (GLS) can detect early functional impairment before structural abnormalities develop. It remains unknown if reduced GLS is associated with reduced survival in patients with MM. We conducted a retrospective cohort analysis of patients diagnosed with MM between 1 January 2000 and 31 December 2017 at our institution. Patients with a 2D transthoracic echocardiogram completed within 1 year of MM diagnosis, left ventricular ejection fraction (LVEF) greater than 40%, and no history of myocardial infarction prior to MM diagnosis were included. GLS was measured using an artificial-intelligence-powered software (EchoGo Core), with reduced GLS defined as an absolute value of <18%. The primary outcome of interest was overall survival since myeloma diagnosis. Our cohort included 242 patients with a median follow up of 4.28 years. Fifty-two (21.5%) patients had reduced average GLS. Patients with reduced GLS were more likely to have an IVSd ≥ 1.2cm, E/E' > 9.6, LVEF/GLS > 4.1, higher LV mass index, and low-voltage ECG. A Total of 126 (52.1%) deaths occurred during follow-up. Overall survival was lower among patients with reduced GLS (adjusted HR: 1.81, CI: 1.07-3.05).

Assisted reality device to guide cardiac implantable device programming in distant rural areas

BACKGROUND

Patients with cardiac implantable electronic devices (CIEDs) living in rural areas have difficulty obtaining follow-up visits for device interrogation and programming in specialized healthcare facilities.

OBJECTIVE

To describe the use of an assisted reality device designed to provide front-line workers with real-time online support from a remotely located specialist (Realwear HTM-1; Realwear) during CIED assistance in distant rural areas.

METHODS

This is a prospective study of patients requiring CIED interrogation using the Realwear HMT-1 in a remote rural population in Colombia between April 2021 and June 2022. CIED interrogation and device programming were performed by a general practitioner and guided by a cardiac electrophysiologist. Non-CIED-related medical interventions were allowed and analyzed. The primary objective was to determine the incidence of clinically significant CIED alerts. Secondary objectives were the changes medical interventions used to treat the events found in the device interrogations regarding non-CIED related conditions.

RESULTS

A total of 205 CIED interrogations were performed on 139 patients (age 69 ± 14 years; 54% female). Clinically significant CIED alerts were reported in 42% of CIED interrogations, consisting of the detection of significant arrhythmias (35%), lead malfunction (3%), and device in elective replacement interval (3.9%). Oral anticoagulation was initiated in 8% of patients and general medical/cardiac interventions unrelated to the CIED were performed in 52% of CIED encounters.

CONCLUSION

Remote assistance using a commercially available assisted reality device has the potential to provide specialized healthcare to patients in difficult-to-reach areas, overcoming current difficulties associated with RM, including the inability to change device programming. Additionally, these interactions provided care beyond CIED-related interventions, thus delivering significant social and clinical impact to remote rural populations.

Current practice in transvenous lead extraction in Latin America: Latin American Heart Rhythm Association survey

BACKGROUND

Transvenous lead extraction (TLE) is standard of care for the management of patients with cardiac implantable electronic device infection or lead-related complications. Currently, objective data on TLE in Latin America is lacking.

OBJECTIVE

To describe the current practice standards in Latin American centers performing TLE.

METHODS

An online survey was sent through the mailing list of the Latin American Heart Rhythm Society. Online reminders were sent through the mailing list; duplicate answers were discarded. The survey was available for 1 month, after which no more answers were accepted.

RESULTS

A total of 48 answers were received, from 44 different institutions (39.6% from Colombia, 27.1% from Brazil), with most respondents (82%) being electrophysiologists. Twenty-nine institutions (66%) performed <10 lead extractions/year, with 7 (16%) institutions not performing lead extraction. Although most institutions in which lead extraction is performed reported using several tools, mechanical rotating sheaths were cited as the main tool (66%) and only 13% reported the use of laser sheaths. Management of infected leads was performed according to current guidelines.

CONCLUSION

This survey is the first attempt to provide information on TLE procedures in Latin America and could provide useful information for future prospective registries. According to our results, the number of centers performing high volume lead extraction in Latin America is smaller than that reported in other continents, with most interventions performed using mechanical tools. Future prospective registries assessing acute and long-term success are needed.

Long-Term Outcomes of Left Atrial Appendage Electrical Isolation in Patients With Nonparoxysmal Atrial Fibrillation

Background:

Left atrial appendage electrical isolation (LAAEI) has been proposed for the treatment of nonparoxysmal atrial fibrillation (AF). The long-term clinical outcomes of this approach remain unclear. The objective of our study was to investigate the incremental benefit and safety of LAAEI in patients undergoing catheter ablation for nonparoxysmal AF.

Methods:

Propensity score-matched analysis was performed using a prospective registry database from 2010 to 2014. All patients in the LAAEI group were matched based on baseline characteristics, echocardiographic parameters, and procedural ablation techniques.

Results:

We identified 1842 patients who underwent catheter ablation for nonparoxysmal AF. Propensity score matching yielded 1092 patients, 546 patients with LAAEI, and 546 patients without LAAEI. At 5-year follow-up, overall freedom from all-atrial arrhythmia recurrence, off-antiarrhythmic drugs, in patients who underwent LAAEI was 68.9% versus 50.2% in those who underwent standard ablation alone ( P <0.001). Acute complication rates were similar between groups (LAAEI 1.3% versus non-LAAEI 0.73%, P =0.36). At 5-year follow-up, 382 (70%) patients in the LAAEI group remained on oral anticoagulation versus 217 (39.7%) in the non-LAAEI group. At 5-year follow-up, thromboembolic events occurred in 15/546 (2.75%) in the LAAEI group and 4/546 (0.73%) in the non-LAAEI group ( P =0.01). No thromboembolic events occurred in either group on-oral anticoagulation. In patients who were off-oral anticoagulation, at 5-year follow-up, thromboembolic events occurred in 15/164 (9.1%) in the LAAEI group and 4/329 (1.2%) in the non-LAAEI group ( P <0.001).

Conclusions:

At 5-year follow-up, LAAEI was associated with significantly higher freedom from all-atrial arrhythmia recurrence in patients with persistent and long-standing persistent AF without increasing acute procedural complication rate. In patients off-oral anticoagulation, there appears to be a higher risk of thromboembolic events in the LAAEI group.

Cavotricuspid isthmus line in patients undergoing catheter ablation of atrial fibrillation with or without history of typical atrial flutter: A meta-analysis

BACKGROUND

Pulmonary vein isolation (PVI) is the mainstay of catheter ablation (CA) for paroxysmal atrial fibrillation (AF). However, for persistent and long-standing persistent AF, there are no established strategies to improve the success rate of CA. Despite studies indicating that prophylactic cavotricuspid isthmus (CTI) ablation provides no or limited incremental benefit in patients with AF, it is still routinely performed worldwide.

OBJECTIVE

We sought to examine whether CTI ablation for AF is associated with improvement in recurrence of all-atrial arrhythmias, compared with PVI alone in patients with and without typical atrial flutter (AFL).

METHODS

A systematic review of PubMed, Cochrane, and Embase was performed for clinical studies including AF patients, reporting outcomes of CTI + PVI versus PVI alone. The primary efficacy endpoint was recurrence of all-atrial arrhythmias.

RESULTS

Five studies comprising 1400 patients undergoing CTI + PVI versus PVI alone were included; 1110 patients had AF without AFL, and 290 patients had coexistent AF and AFL. After a mean follow-up of 14.4 ± 4.8 months, CTI + PVI was not associated with improvement in recurrence of all-atrial arrhythmias when compared with PVI alone (risk ratio [RR]: 1.29; 95% confidence interval [CI]: 0.93-1.79;p = .13). In the subgroup analysis, there were no differences between both groups in patients with AF without AFL (RR: 1.55; 95% CI: 0.96-2.48; p = .07), and in patients with AF and AFL (RR: 0.91; 95% CI: 0.6-1.39; p = .68).

CONCLUSION

In AF patients, irrespective of the presence of typical AFL, additional CTI ablation is not associated with improvement in recurrence of all-atrial arrhythmias, compared with PVI alone.

Safety of catheter ablation for atrial fibrillation in the octogenarian population

INTRODUCTION

Catheter ablation (CA) has been shown to be an effective treatment for atrial fibrillation (AF). The complication rates and outcomes among octogenarians remain poorly studied. We aimed to compare trends, morbidity, and mortality associated with CA for AF among octogenarians versus those less than 80 years old.

METHODS

Using weighted sampling from the National Inpatient Sample database, we identified patients with a primary diagnosis of AF and a primary procedure of CA (2004-2013). Our primary outcome was mortality. Secondary outcomes included incidence of major and minor complications.

RESULTS

Among 86,119 patients who underwent CA for AF, 3,482 were 80 years old or older. Complications were significantly more frequent in octogenarians; [16.2% (564 of 3,482) versus 9.8% (8,092 of 82,637), P < 0.001]. Of note, there was no significant difference for the composite of major complications; [3.6% (124 of 3482) in octogenarians versus 2.8% (2286 of 82637), P = 0.20]. The total mortality rate was not significant in a multivariate regression analysis (odds ratio [OR], 0.96; 95% confidence interval [CI], 0.35-2.64; P = .94). The presence of chronic renal failure (OR, 4.19; 95% CI, 2.75-6.36; P < 0.001), anemia (OR, 1.75; 95% CI, 1.03-2.97; P = .04), and chronic pulmonary disease (OR, 1.75; 95% CI, 1.11-2.62; P = .015) were predictors of major complications in octogenarians.

CONCLUSION

Catheter ablation for AF in octogenarians does not confer a higher mortality risk than in those less than 80 years old. The procedure is associated with a higher rate of overall complications but there was no difference in terms of major complications or death. The presence of anemia, CKD or pulmonary disease were predictors of major complications in octogenarians.

Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy

We measure the energy emitted by extensive air showers in the form of radio emission in the frequency range from 30 to 80 MHz. Exploiting the accurate energy scale of the Pierre Auger Observatory, we obtain a radiation energy of 15.8±0.7(stat)±6.7(syst)  MeV for cosmic rays with an energy of 1 EeV arriving perpendicularly to a geomagnetic field of 0.24 G, scaling quadratically with the cosmic-ray energy. A comparison with predictions from state-of-the-art first-principles calculations shows agreement with our measurement. The radiation energy provides direct access to the calorimetric energy in the electromagnetic cascade of extensive air showers. Comparison with our result thus allows the direct calibration of any cosmic-ray radio detector against the well-established energy scale of the Pierre Auger Observatory.

Measurement of the depth of maximum of extensive air showers above 10{18} eV

We describe the measurement of the depth of maximum, X{max}, of the longitudinal development of air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed by the fluorescence detector of the Pierre Auger Observatory in coincidence with at least one surface detector station are selected for the analysis. The average shower maximum was found to evolve with energy at a rate of (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) g/cm{2}/decade above this energy. The measured shower-to-shower fluctuations decrease from about 55 to 26 g/cm{2}. The interpretation of these results in terms of the cosmic ray mass composition is briefly discussed.

Enhancement in liver SREBP-1c/PPAR-alpha ratio and steatosis in obese patients: correlations with insulin resistance and n-3 long-chain polyunsaturated fatty acid depletion

Sterol receptor element-binding protein-1c (SREBP-1c) and peroxisome proliferator-activated receptor-alpha (PPAR-alpha) mRNA expression was assessed in liver as signaling mechanisms associated with steatosis in obese patients. Liver SREBP-1c and PPAR-alpha mRNA (RT-PCR), fatty acid synthase (FAS) and carnitine palmitoyltransferase-1a (CPT-1a) mRNA (real-time RT-PCR), and n-3 long-chain polyunsaturated fatty acid (LCPUFA)(GLC) contents, plasma adiponectin levels (RIA), and insulin resistance (IR) evolution (HOMA) were evaluated in 11 obese patients who underwent subtotal gastrectomy with gastro-jejunal anastomosis in Roux-en-Y and 8 non-obese subjects who underwent laparoscopic cholecystectomy (controls). Liver SREBP-1c and FAS mRNA levels were 33% and 70% higher than control values (P<0.05), respectively, whereas those of PPAR-alpha and CPT-1a were 16% and 65% lower (P<0.05), respectively, with a significant 62% enhancement in the SREBP-1c/PPAR-alpha ratio. Liver n-3 LCPUFA levels were 53% lower in obese patients who also showed IR and hipoadiponectinemia over controls (P<0.05). IR negatively correlated with both the hepatic content of n-3 LCPUFA (r=-0.55; P<0.01) and the plasma levels of adiponectin (r=-0.62; P<0.005). Liver SREBP-1c/PPAR-alpha ratio and n-3 LCPUFA showed a negative correlation (r=-0.48; P<0.02) and positive associations with either HOMA (r=0.75; P<0.0001) or serum insulin levels (r=0.69; P<0.001). In conclusion, liver up-regulation of SREBP-1c and down-regulation of PPAR-alpha occur in obese patients, with enhancement in the SREBP-1c/PPAR-alpha ratio associated with n-3 LCPUFA depletion and IR, a condition that may favor lipogenesis over FA oxidation thereby leading to steatosis.

Individual radiation therapy patient whole-body phantoms for peripheral dose evaluations: method and specific software

This study presents a method aimed at creating radiotherapy (RT) patient-adjustable whole-body phantoms to permit retrospective and prospective peripheral dose evaluations for enhanced patient radioprotection. Our strategy involves virtual whole-body patient models (WBPM) in different RT treatment positions for both genders and for different age groups. It includes a software tool designed to match the anatomy of the phantoms with the anatomy of the actual patients, based on the quality of patient data available. The procedure for adjusting a WBPM to patient morphology includes typical dimensions available in basic auxological tables for the French population. Adjustment is semi-automatic. Because of the complexity of the human anatomy, skilled personnel are required to validate changes made in the phantom anatomy. This research is part of a global project aimed at proposing appropriate methods and software tools capable of reconstituting the anatomy and dose evaluations in the entire body of RT patients in an adapted treatment planning system (TPS). The graphic user interface is that of a TPS adapted to obtain a comfortable working process. Such WBPM have been used to supplement patient therapy planning images, usually restricted to regions involved in treatment. Here we report, as an example, the case of a patient treated for prostate cancer whose therapy planning images were complemented by an anatomy model. Although present results are preliminary and our research is ongoing, they appear encouraging, since such patient-adjusted phantoms are crucial in the optimization of radiation protection of patients and for follow-up studies.

Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV

The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

Upper limit on the diffuse flux of ultrahigh energy tau neutrinos from the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory is sensitive to Earth-skimming tau neutrinos that interact in Earth's crust. Tau leptons from nu(tau) charged-current interactions can emerge and decay in the atmosphere to produce a nearly horizontal shower with a significant electromagnetic component. The data collected between 1 January 2004 and 31 August 2007 are used to place an upper limit on the diffuse flux of nu(tau) at EeV energies. Assuming an E(nu)(-2) differential energy spectrum the limit set at 90% C.L. is E(nu)(2)dN(nu)(tau)/dE(nu)<1.3 x 10(-7) GeV cm(-2) s(-1) sr(-1) in the energy range 2 x 10(17) eV< E(nu)< 2 x 10(19) eV.

Abeta ion channels. Prospects for treating Alzheimer's disease with Abeta channel blockers

The main pathological features in the Alzheimer's brain are progressive depositions of amyloid protein plaques among nerve cells, and neurofibrillary tangles within the nerve cells. The major components of plaques are Abeta peptides. Numerous reports have provided evidence that Abeta peptides are cytotoxic and may play a role in the pathogenesis of AD. An increasing number of research reports support the concept that the Abeta-membrane interaction event may be followed by the insertion of Abeta into the membrane in a structural configuration which forms an ion channel. This review summarizes experimental procedures which have been designed to test the hypothesis that the interaction of Abeta with a variety of membranes, both artificial and natural, results in the subsequent formation of Abeta ion channels We describe experiments, by ourselves and others, that support the view that Abeta is cytotoxic largely due to the action of Abeta channels in the cell membrane. The interaction of Abeta with the surface of the cell membrane may results in the activation of a chain of processes that, when large enough, become cytotoxic and induce cell death by apoptosis. Remarkably, the blockage of Abeta ion channels at the surface of the cell absolutely prevents the activation of these processes at different intracellular levels, thereby preserving the life of the cells. As a prospect for therapy for Alzheimer's disease, our findings at cellular level may be testable on AD animal models to elucidate the potential role and the magnitude of the contribution of the Abeta channels for induction of the disease.

Serum folate and homocysteine levels in obese females with non-alcoholic fatty liver

OBJECTIVE

Folate depletion and hyperhomocysteinemia increase the risk for hepatic alcoholic damage and promote oxidative stress in animals. In addition, some investigators have reported an inverse association between serum folate and body mass index and a positive correlation between total homocysteine and fat mass. We investigated whether there is an association between serum folate and total homocysteine concentrations with the presence of non-alcoholic fatty liver disease (NAFLD) in obese subjects.

METHODS

Forty-three obese (body mass index > or =35 kg/m2) patients who underwent bariatric surgery and hepatic biopsy were included. Serum total homocyteine, folate and vitamin B12 concentrations and hepatic enzymes were measured. Liver biopsies were graded for the presence of fat, inflammation, and fibrosis on a scale from 0 to 3. A total histologic score was calculated based on the sum of partial scores. Severe NAFLD was defined as a total score of at least 4 or severe steatosis (partial score for fat = 3).

RESULTS

Severe NAFLD was present in 17 patients. Serum folate concentration was significantly lower in obese patients with NAFLD than in those with normal liver or minimal alterations (9.3 +/- 3.5 versus 12.2 +/- 3.1 ng/mL, P = 0.005). Serum total homocysteine and vitamin B12 concentrations were similar in both groups. An inverse correlation between serum folate concentration and body mass index was observed (r = -0.31, P = 0.046).

CONCLUSIONS

In this study, severe NAFLD in obese subjects was associated with lower serum folate concentrations and serum homocysteine and vitamin B12 concentrations were not associated with liver damage in obese subjects.

Oxidative stress-related parameters in the liver of non-alcoholic fatty liver disease patients

Oxidative stress is implicated in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). In the present study, hepatic and plasma oxidative stress-related parameters were measured and correlated with clinical and histological findings in 31 NAFLD patients showing increased body mass index. Liver protein carbonyl content was enhanced by 403% in patients with steatosis (n=15) compared with control values (n=12), whereas glutathione content, superoxide dismutase (SOD) activity and the ferric reducing ability of plasma (FRAP) were decreased by 57%, 48% and 21% (P<0.05) respectively. No changes in microsomal p-nitrophenol hydroxylation and the total content of cytochrome P450 (CYP) or CYP2E1 were observed. Patients with steatohepatitis (n=16) exhibited protein carbonyl content comparable with that of controls, whereas glutathione content, SOD and catalase activities were decreased by 27%, 64% and 48% (P<0.05). In addition, FRAP values in patients with steatohepatitis were reduced by 33% and 15% (P<0.05) when compared with controls and patients with steatosis respectively, whereas p-nitrophenol hydroxylation (52%) and CYP2E1 content (142%) were significantly increased (P<0.05) compared with controls. It is concluded that oxidative stress is developed in the liver of NAFLD patients with steatosis and is exacerbated further in patients with steatohepatitis, which is associated with CYP2E1 induction. Substantial protein oxidation is followed by proteolysis of the modified proteins, which may explain the co-existence of a diminished antioxidant capacity and protein oxidation in the liver of patients with steatohepatitis.

[Method of radiotherapy planning for head and neck tumors using simulated CT images and radiographic data, developed at the Gustave Roussy Institute]

The paper deals with the recent improvements introduced in the most usual method applied in the Institut Gustave Roussy radiotherapy department for obtaining the anatomical data of patients treated for head and neck tumors. For each of these patients, five to seven transverses slices and a lateral radiographic film are taken from a Mecaserto simulator-CT. The anatomical representation of the patient sagittal plane is carried out from the digitalisation of the radiographic film on a Vidar Vxr-12 Plus film scanner and integrated into the Dosigray dose calculation programme in order to be used as a support for the laying out of the dose distribution in reference to the treatment. The sagittal anatomical representation obtained from the radiographic film digitalisation is compared with the one resulting from the interpolation between a limited number of irregularly-spaced transverse slices taken on the simulator-CT. The method using the simulator-scanner transverse slices and the radiographic film digitalisation represents an interesting alternative for obtaining an anatomy simulation representative of the patient in hospitals where a scanner is not available full-time for the needs of the radiotherapy process.

[Intensity modulation by inverse planning: preliminary results]

An inverse planning algorithm for determining the intensity of modulated beams that generates conformal radiotherapy dose distributions is presented. This algorithm is based on the mathematical analysis of the singular values decomposition. It is integrated in the DOSIGRAY 3D treatment planning software. The dose is calculated by the separation of the primary and scattered radiation. We presented, for a prostate cancer, the modulated intensity profiles and the optimal dose distribution obtained by the inverse optimization software developed and integrated in the treatment planning system. We obtained a region with high doses which geometrically conforms the target volume and spares the neighboring critical structures. This preliminary study showed the feasibility and the managing of the singular value decomposition to generate conformal dose distribution in a clinical environment.

Identification of Microthoracius mazzai (Phthiraptera: Anoplura) as an economically important parasite of alpacas

The hematophagous sucking louse Microthoracius mazzai Werneck, 1932, is redescribed and identified as a parasite of alpacas, Lama pacos L. Specimens were collected on animals 10-14 mo old, located on a large community farm at 4,600 m above sea level in the Peruvian Andes. In total, 26 scanning electron microscope (SEM) figures are included that highlight salient and differential characteristics, especially the unique elongated spindle-shaped head, which is almost as long as its abdomen. Alpacas, 1 of the 4 species of South American camelids, are important for their production of high-quality wool in the Andes Mountain range countries, especially Peru and Bolivia; to a lesser degree Chile; and more recently Argentina, where breeding and disease control programs are receiving increased technical support. Information is given on the prevalence of lice infestations in the flock, clinical signs, and economic losses. We report the efficacy of moxidectin (SC, 200 mcg/kg, b.w.) in a repeated treatment program of 7-10 d, which is currently used for mange control in these ruminants.

Present role of classic open choledochostomy in the surgical treatment of patients with common bile duct stones

Open choledochostomy still represents an important step of biliary surgery, even during the era of laparoscopic surgery. Although its application has decreased with the widespread use of endoscopic retrograde cholangiopancreatography (ERCP) and papillotomy, still there are some patients in whom it is necessary to perform open choledochostomy and place a T-tube. The morbidity and mortality rates depend mainly on the presence or absence of an acute suppurative cholangitis, rather than the performance of the choledochostomy. In patients with mild cholangitis or those no cholangitis and less than 60 years of age, the mortality rate is lower than that observed after ERCP. This procedure is still an important technique for surgeons dedicated to biliary surgery, and therefore several technical aspects of common bile duct exploration are important to remember.

Prevalence of common bile duct stones according to the increasing number of risk factors present. A prospective study employing routinely intraoperative cholangiography in 477 cases

BACKGROUND/AIMS

To determine if the use of Intraoperative choliangiography (IOC) should be routinely performed and, if not, which criteria should be used to select patients requiring IOC during open or laparoscopic cholecystectomy.

METHODOLOGY

495 Patients with 1 or more gallstones were included in a two-year study. Twelve clinical, laboratory, ultrasonographic and intraoperative factors were chosen and evaluated in all cases. Prior to cholecystectomy, IOC was performed after having identified the common bile duct (CBD) and cystic duct. The majority of the patients were operated on by the same surgeon to avoid differences in criteria and techniques. Statistical evaluation made use of the exact Fisher test and chi square test and, a p-value less than 0.05 was considered as significant.

RESULTS

IOC could be performed in 479 out of the 495 cases. IOC resulted in a normal CBD in 76.0%, had a false positive in 2.7%, a false negative in 0.48%, and a presence of 1 or more stones in the CBD in 20.9%. The study revealed that when none of the 12 risk factors were present, there were no cases with CBD stones. As the number of risk factors increased, so did the number of cases presenting with CBD stones.

CONCLUSION

Not all 12 risk factors show the same index of predictability; only 5 in particular (jaundice, ultrasound diameter CBD 7 mm, bilirubin over 26 umol/it, cystic duct > 4 mm and CBI, diameter over 9 mm) showed a high rate of predictability. However, when careful measurement and evaluation of risk factors for CBD stones are undertaken, it is possible to avoid the routine use of IOC.

Laparoscopic highly selective vagotomy: technical considerations and preliminary results in 119 patients with duodenal ulcer or gastroesophageal reflux disease

The technical considerations and preliminary results of 119 patients submitted to laparoscopic highly selective vagotomy are presented. There were 33 with duodenal ulcers, 31 with duodenal ulcers plus gastroesophageal reflux, and 55 with gastroesophageal reflux. Operating time varied from 120 to 160 minutes. Six complications occurred: four perforations of the gastric fundus and two bleeding episodes. Conversion to open surgery was done in four cases and reoperation in one case. No deaths occurred, and the mean hospital stay was 3 days. The mean follow-up was 16 months, being 94% of the cases with Visick I or II and 6% with Visick III or IV. This technique is completely feasible by laparoscopic procedure and reproduces exactly what has been done with the laparotomy approach.

Counts of bacteria and pyocites of choledochal bile in controls and in patients with gallstones or common bile duct stones with or without acute cholangitis

BACKGROUND/AIMS

The number of colonies of bacteria and the number of pyocites present per ml of choledochal bile was studied.

PATIENTS AND METHODS

There were 42 controls, 100 patients with symptomatic gallstones, 42 patients with common duct stones without cholangitis and 24 patients with common duct stones and acute cholangitis.

RESULTS

Control subjects had no bacteria present at gallbladder bile. Only 3% of patients with gallstones had more than 10(5) colonies per ml which increased to 36% in patients with common duct stones without cholangitis and to 84% among patients with acute cholangitis (p < 0.001). There were more polybacterial flora among patients with acute cholangitis and anaerobic bacteria were not seen in patients with gallstones. Patients with acute cholangitis had significantly more pyocites present at choledochal bile.

CONCLUSION

There is a direct correlation between the number of colonies present per ml of choledochal bile and the severity of biliary tract disease. Patients with acute cholangitis had significantly more pyocites present at choledochal bile compared to gallstones or patients with CBD stones without cholangitis.

Simultaneous bacteriologic assessment of bile from gallbladder and common bile duct in control subjects and patients with gallstones and common duct stones

OBJECTIVES

To determine the simultaneous prevalence of bacteria in bile from the gallbladder and common bile duct and to determine the influence of the number of stones present on bacteriologic findings.

METHODS

A prospective study was performed in 467 subjects divided into seven groups: 42 control subjects with normal biliary tracts, 221 patients with symptomatic gallstone disease, 12 patients with hydropic gallbladder, 52 patients with acute cholecystitis, 67 patients with common bile duct stones without cholangitis, 49 patients with common bile duct stones and acute cholangitis, and 24 patients with previous cholecystectomy and common bile duct stones. In all except controls, bile samples from the gallbladder and common bile duct were taken simultaneously for aerobic and anaerobic cultures.

RESULTS

Control subjects had no bacteria in gallbladder bile. Patients with gallstones, acute cholecystitis, and hydropic gallbladder had similar rates of positive cultures in the gallbladder and common bile duct, ranging from 22% to 46%, but the rate was significantly higher in patients with common bile duct stones without cholangitis (58.2%). Patients with cholangitis or previous cholecystectomy had a high rate of positive cultures of common duct bile (93% to 100%). Age greater than 60 years had a significant influence on the rate of positive bile cultures. There was no relationship between the number of stones in the gallbladder or common bile duct and the percentage of positive cultures. In 98% of the patients, the same bacteria were isolated from gallbladder and common duct bile.

CONCLUSIONS

In normal subjects, no bacteria were present in the biliary tract. Among patients with common bile duct stones, there was an increasing percentage of positive cultures according to the severity of the disease. Age had an important influence, but sex and the number of common bile duct stones had no influence on positive cultures.

Bacteriological studies of liver parenchyma in controls and in patients with gallstones or common bile duct stones with or without acute cholangitis

BACKGROUND/AIMS

The presence of aerobic and/or anaerobic bacteria in the liver parenchyma, gallbladder bile, and common bile duct was investigated.

MATERIALS AND METHODS

There were 15 control subjects, 32 cases with symptomatic gallstones, 16 patients with common bile duct stones without acute cholangitis and 8 cases with common bile duct stones with an acute suppurative cholangitis.

RESULTS

No bacteria were isolated in controls. The percentage of positive cultures in liver parenchyma increased in proportion to the severity of the biliary tract disease. There was no clear correlation between normal and altered hepatic histology and the presence or absence of bacteria except in patients with acute cholangitis.

CONCLUSIONS

When biliary tract obstruction is present, the biliary tract is more vulnerable to invasion of bacteria and therefore increases the chance of spread into the liver parenchyma.

Results of Heineke-Mikulicz type choledochoplasty in benign biliary strictures

During a 20-year period from 1970 to 1991, a total of 30,800 patients underwent biliary tract surgery at the Department of Surgery, University of Chile Clinical Hospital. Of these, seven female adults with a mean age of 39.7 years (range 29 to 54) were considered for analysis in this study. The results of the Heineke-Mikulicz type choledochoplasty repair in patients with short localized strictures of the biliary tract were analyzed in these patients. In six cases, the repair was performed at a mean time of 20 months after cholecystectomy and accidental injury of the common bile duct; in one case it was carried out during cholecystectomy and repair of a Mirizzi type II cholecysto-hepatic fistula. This patient remained asymptomatic during a follow-up of 120 months. Of the six cases on whom choledochoplasty was performed as treatment of short strictures, five patients (83%) developed a new stricture at a mean time of 14 months after surgery; a hepatico-jejunostomy was performed in all. After this procedure, only one patient was re-operated again, and all remained asymptomatic long after surgery. We believe that this Heineke-Mikulicz type choledochoplasty, which has been recommended in short distal strictures, is not advisable as a definitive surgical repair for this kind of stricture.

Prospective randomized study comparing three surgical techniques for the treatment of gastric outlet obstruction secondary to duodenal ulcer

A prospective randomized clinical trial was performed in order to evaluate the results of three surgical techniques for the treatment of gastric outlet obstruction secondary to duodenal ulcer. Ninety patients with clinical and laboratory evidence of gastric retention were enrolled. After laparotomy, patients underwent either highly selective vagotomy (HSV) + gastrojejunostomy, HSV + Jaboulay gastroduodenostomy, or selective vagotomy (SV) + antrectomy. One patient died after HSV + Jaboulay gastroduodenostomy due to postoperative acute pancreatitis. There were no differences in the postoperative course of the three groups. Patients were followed for a mean of 98 months (range: 30 to 156 months). There was a significantly better result after HSV + gastrojejunostomy than after Jaboulay anastomosis (p < 0.01), but not after SV + antrectomy. Gastric acid reduction was similar in the small group of patients studied. We propose HSV + gastrojejunostomy as the treatment of choice in patients with duodenal ulcer and gastric outlet obstruction.

Risk factors and classification of acute suppurative cholangitis

A prospective study was performed in 1282 patients with common bile duct stones to determine the clinical and laboratory parameters that could predict cholangitis, and the factors associated with greater severity of cholangitis. Patients were divided into two groups, with or without acute cholangitis, depending on the macroscopic appearance of bile aspirated from the common bile duct during surgery. Acute cholangitis was diagnosed when the aspirated fluid was turbid or clearly pus; the typical Charcot's triad was present in only 22 per cent of patients with acute cholangitis. Several clinical and laboratory parameters were significantly more common in these patients and, depending on their number, the probability of acute cholangitis increased significantly. The operative mortality rate was 1.2 per cent for patients without cholangitis and 11.9 per cent for patients with cholangitis. Depending on the number of factors present, patients with cholangitis were divided into three groups: mild acute cholangitis without mortality; moderate acute cholangitis with a mortality rate of 5.6 per cent; and severe acute cholangitis with a mortality rate of 27.5 per cent. The present classification allows the group of patients needing prompt endoscopic or surgical drainage to be identified.

[Diagnosis of gastroesophageal reflux by radioisotopic techniques]

We evaluated 148 patients (mean age 45 years) with clinically evident gastroesophageal reflux. A radioisotopic test with 99mTc sulphur-colloid was performed in all; endoscopy in 146, biopsy in 24, acid reflux test and manometric evaluation in 141 and radiologic studies in 85. Sensitivity of the different techniques was: radioisotopes 92%, radiology 87%, acid reflux test 84%; endoscopy 63% and manometric studies 61%. Severity of reflux and esophagitis was adequately predicted from radioisotopic evaluation. We conclude that this radioisotopic test is highly reliable for the diagnosis of gastroesophageal reflux.

Treatment of residual common bile duct stones after cholecystectomy

This study was conducted to determine the occurrence of "open" residual common bile duct stones after cholecystectomy to establish predisposing factors and possible alternative treatments. Correct diagnosis of choledocholithiasis before or during surgery, adequate exploration of the common bile duct, and suitable selection of technical procedures are the most important points in preventing retained CBD stones. If these occur, an adequate alternative treatment may prove helpful. Classical "clysis" of the bile duct is least recommended because of its high failure rate. The best method of chemical dissolution seems to be the use of mono-octanoin with 60% good results and a no-response rate of 30-40%. Instrumental extraction has been reported to be very successful (80-98%). Endoscopic sphincterotomy is currently the most frequently employed procedure for retained CBD stones, especially in poor risk patients. The reported success rate is 82-93% according to literature, with an extremely low mortality (0.2%). Reoperation should be resorted to only if all the other methods fail. Sphincteroplasty or choledochoduodenostomy, whenever indicated, are good alternative operations, with a mortality rate of approx. 3.5%.

Factors affecting mortality in patients over 70 years of age submitted to surgery for gallbladder or common bile duct stones

Chile is the country with the highest incidence of gallstone disease in the world. Nearly 44% of the women and 25% of the men over 20 years of age have gallstones. Biliary tract surgery accounts for about 35% of all the operations performed in Chilean general hospitals. The present paper aims at assessing the risk factors associated with a higher mortality in patients over 70 years of age subjected to elective or emergency surgery for gallstones or common bile duct stones. No specific factors of mortality were found in the group of elderly patients subjected to elective cholecystectomy. There was also no correlation between types of cholecystitis and postoperative mortality. However, acute suppurative cholangitis made the postoperative mortality rate increase almost 20-fold in patients with common bile duct stones. The mortality also shows a steep increase (up to 12%) if cholecystectomy is performed in acute cholecystitis. Cholecystostomy seems to be associated with a low mortality risk and hence should be appropriate in exceptionally high-risk patients, but is not considered useful by the authors in necrotic or gangrenous cholecystitis, or in cases with common bile duct stones and cholangitis. Postoperative mortality in patients submitted to cholecystectomy alone seems to depend exclusively on the concomitant presence of medical complications, mainly of a respiratory and cardiovascular nature. Septic complications are important causes of postoperative mortality in emergency cholecystectomy. Patients at high surgical risk are those suspected of cholangitis, those over 80 years of age, and those suffering from Charcot's triad, anemia, uremia, leukocytosis, hyperbilirubinemia or hypoprothrombinemia; in these, an endoscopic procedure could be chosen.