Outcomes of conduction system pacing for cardiac resynchronization therapy in patients with heart failure: A multicenter experience

BACKGROUND

Whether conduction system pacing (CSP) is an alternative option for cardiac resynchronization therapy (CRT) in patients with heart failure remains an area of active investigation.

OBJECTIVE

The purpose of this study was to assess the echocardiographic and clinical outcomes of CSP compared to biventricular pacing (BiVP).

METHODS

This multicenter retrospective study included patients who fulfilled CRT indications and received CSP. Patients with CSP were matched using propensity score matching and compared in a 1:1 ratio to patients who received BiVP. Echocardiographic and clinical outcomes were assessed. Response to CRT was defined as an absolute increase of ≥5% in left ventricular ejection fraction (LVEF) at 6 months post-CRT.

RESULTS

A total of 238 patients were included. Mean age was 69.8 ± 12.5 years, and 66 (27.7%) were female. Sixty-nine patients (29%) had His-bundle pacing, 50 (21%) had left bundle branch area pacing, and 119 (50%) had BiVP. Mean follow-up duration in the CSP and BiVP groups was 269 ± 202 days and 304 ± 262 days, respectively (P = .293). The proportion of CRT responders was greater in the CSP group than in the BiVP group (74% vs 60%, respectively; P = .042). On Kaplan-Meier analysis, there was no statistically significant difference in the time to first heart failure hospitalization (log-rank P = .78) and overall survival (log-rank P = .68) between the CSP and BiVP groups.

CONCLUSION

In patients with heart failure and reduced ejection fraction, CSP resulted in greater improvement in LVEF compared to BiVP. Large-scale randomized trials are needed to validate these outcomes and further investigate the different options available for CSP.

Stellate ganglion instrumentation for pharmacological blockade, nerve recording, and stimulation in patients with ventricular arrhythmias: Preliminary experience

BACKGROUND

Stellate ganglion blockade (SGB) can control ventricular arrhythmias (VAs), but outcomes are unclear. Percutaneous stellate ganglion (SG) recording and stimulation in humans has not been reported.

OBJECTIVE

The purpose of this study was to assess the outcomes of SGB and the feasibility of SG stimulation and recording in humans with VAs.

METHODS

Two patient cohorts were included-group 1: patients undergoing SGB for drug-refractory VAs. SGB was performed by injection of liposomal bupivacaine. Incidence of VAs at 24 and 72 hours and clinical outcomes were collected; group 2: patients undergoing SG stimulation and recording during VA ablation; a 2-F octapolar catheter was placed at the SG at the C7 level. Recording (30 kHz sampling, 0.5-2 kHz filter) and stimulation (up to 80 mA output, 50 Hz, 2 ms pulse width for 20-30 seconds) was performed.

RESULTS

Group 1 included 25 patients [age 59.2 ± 12.8 years; 19 (76%) men] who underwent SGB for VAs. Nineteen patients (76.0%) were free of VA up to 72 hours postprocedure. However, 15 (60.0%) had VAs recurrence for a mean of 5.47 ± 4.52 days. Group 2 included 11 patients (mean age 63 ± 12.7 years; 82.7% men). SG stimulation caused consistent increases in systolic blood pressure. We recorded unequivocal signals with temporal association with arrhythmias in 4 of 11 patients.

CONCLUSION

SGB provides short-term VA control, but has no benefit in the absence of definitive VA therapies. SG recording and stimulation is feasible and may have value to elicit VA and understand neural mechanisms of VA in the electrophysiology laboratory.

Substrate Ablation by Multivein, Multiballoon Coronary Venous Ethanol for Refractory Ventricular Tachycardia in Structural Heart Disease

BACKGROUND

Ablation of ventricular tachycardia (VT) in the setting of structural heart disease often requires extensive substrate elimination that is not always achievable by endocardial radiofrequency ablation. Epicardial ablation is not always feasible. Case reports suggest that venous ethanol ablation (VEA) through a multiballoon, multivein approach can lead to effective substrate ablation, but large data sets are lacking.

METHODS

VEA was performed in 44 consecutive patients with ablation-refractory VT (ischemic, n=21; sarcoid, n=3; Chagas, n=2; idiopathic, n=18). Targeted veins were selected by mapping coronary veins on the epicardial aspect of endocardial scar (identified by bipolar voltage <1.5 mV), using venography and signal recording with a 2F octapolar catheter or by guidewire unipolar signals. Epicardial mapping was performed in 15 patients. Vein segments in the epicardial aspect of VT substrates were treated with double-balloon VEA by blocking flow with 1 balloon while injecting ethanol through the lumen of the second balloon, forcing (and restricting) ethanol between balloons. Multiple balloon deployments and multiple veins were used as needed. In 22 patients, late gadolinium enhancement cardiac magnetic resonance imaged the VEA scar and its evolution.

RESULTS

Median ethanol delivered was 8.75 (interquartile range, 4.5-13) mL. Injected veins included interventricular vein (6), diagonal (5), septal (12), lateral (16), posterolateral (7), and middle cardiac vein (8), covering the entire range of left ventricular locations. Multiple veins were targeted in 14 patients. Ablated areas were visualized intraprocedurally as increased echogenicity on intracardiac echocardiography and incorporated into 3-dimensional maps. After VEA, vein and epicardial ablation maps showed elimination of abnormal electrograms of the VT substrate. Intracardiac echocardiography demonstrated increased intramural echogenicity at the targeted region of the 3-dimensional maps. At 1 year of follow-up, median of 314 (interquartile range, 198-453) days of follow-up, VT recurrence occurred in 7 patients, for a success of 84.1%.

CONCLUSIONS

Multiballoon, multivein intramural ablation by VEA can provide effective substrate ablation in patients with ablation-refractory VT in the setting of structural heart disease over a broad range of left ventricular locations.

Advanced Techniques for Ethanol Ablation of Left Ventricular Summit Region Arrhythmias

BACKGROUND

Coronary venous ethanol ablation (VEA) can be used as a strategy to treat ventricular arrhythmias arising from the left ventricular summit, but collateral flow and technical challenges cannulating intramural veins in complex venous anatomies can limit its use. Advanced techniques for VEA can capitalize on collateral vessels between target and nontarget sites to improve success.

METHODS

Of 55 patients with left ventricular summit ventricular arrhythmia, advanced techniques were used in 15 after initial left ventricular summit intramural vein mapping failed to show suitable targets for single vein, single-balloon VEA. All patients had previous radiofrequency ablation attempts. Techniques included: double-balloon for distal protection to block distal flow and target the proximal portion of a large intramural vein where best signal was proximal (n=6); balloons in 2 different left ventricular summit veins for a cross-fire multivein VEA (n=4); intramural collateral vein-to-vein cannulation to reach of targeted vein via collateral with antegrade ethanol and proximal balloon block (n=2); prolonged ethanol dwell time for vein sclerosis of large intramural vein and subsequent VEA (n=3); and intramural collateral VEA (n=1).

RESULTS

Fifteen (8 females) patients (age 60.6±17.6 years) required advanced techniques. Procedure time was 210±49.9 minutes, fluoroscopy time was 25.3±14.1 minutes, and 113±17.9 cc of contrast was utilized. A median of 7 cc of ethanol was delivered (range, 4-15 cc). Intraprocedural radiofrequency ablation was delivered before ethanol in 9 out of 15 patients but failed. Ethanol achieved acute success in all 15 patients. Ethanol was used as the sole treatment in two patients. At a median follow-up of 194 days, one patient experienced recurrence.

CONCLUSIONS

Advanced techniques capitalizing on venous anatomy can enable successful VEA and selective targeting of arrhythmogenic sites, by blocking distal flow, utilization of collaterals between nontarget and target veins and multivein VEA. Understanding individual anatomy is critical for VEA success.

PET-Driven, Voltage-Guided Atrial Endomyocardial Biopsy Clinches the Diagnosis of Cardiac Sarcoidosis

Endomyocardial biopsy (EMB) is used in diagnosing infiltrative and other suspected cardiomyopathies. We present a case in which positron emission tomography– and electroanatomic mapping-guided EMB of the atrial septum confirmed the diagnosis of cardiac sarcoidosis in a patient with negative findings on ventricular and lymph node biopsy. (Level of Difficulty: Advanced.)

Role of chronic continuous intravenous lidocaine in the clinical management of patients with malignant type 3 long QT syndrome

BACKGROUND

Type 3 long QT syndrome (LQT3) is caused by pathogenic, gain-of-function variants in SCN5A leading to a prolonged action potential, ventricular ectopy, and torsades de pointes. Treatment options include pharmacotherapy, cardiac denervation, and/or device therapy. Rarely, patients with malignant LQT3 require cardiac transplantation.

OBJECTIVE

The purpose of this study was to evaluate the role of chronic continuous intravenous (IV) lidocaine as a therapeutic option for select patients with LQT3 refractory to standard therapy.

METHODS

We performed a retrospective review of patients evaluated and treated at Mayo Clinic and identified 4 of 161 patients with LQT3 (2.5%) who were refractory to standard therapies and therefore treated with IV lidocaine.

RESULTS

There were 4 patients (2 female [50%]). The median age at first IV lidocaine infusion was 2 months (interquartile range 1.5-4.8 months), and the median cumulative duration on IV lidocaine was 11.5 months (interquartile range 8.7-17.8 months). The main indication for IV lidocaine in all patients was persistent ventricular arrhythmias. Before IV lidocaine, all patients received an implantable cardioverter-defibrillator, and while on intermittent IV lidocaine, all patients underwent bilateral cardiac sympathetic denervation. Additionally, 2 (50%) patients had cardiac ablation for premature ventricular complexes. In all patients, lidocaine infusion resulted in a significant reduction of LQT3-triggered cardiac events. The main side effects of IV lidocaine observed were dizziness (n = 2, 50%) and seizures (n = 2, 50%). During follow-up, 3 of 4 (75%) patients underwent orthotopic cardiac transplantation. The remaining patient continues to receive IV lidocaine bolus for rescue as needed.

CONCLUSION

For patients with LQT3 who are refractory to standard treatment, chronic IV lidocaine infusion can be used as a potential "bridge to transplant."

Venous anatomy of the left ventricular summit: Therapeutic implications for ethanol infusion

BACKGROUND

Venous ethanol ablation (VEA) is effective for treatment of left ventricular (LV) summit (LVS) arrhythmias. The LVS venous anatomy is poorly understood and has inconsistent nomenclature.

OBJECTIVE

The purpose of this study was to delineate the LVS venous anatomy by selective venography and 3-dimensional (3D) mapping during VEA and by venous-phase coronary computed tomographic angiography (vCTA).

METHODS

We analyzed (1) LVS venograms and 3D maps of 53 patients undergoing VEA; and (2) 3D reconstructions of 52 vCTAs, tracing LVS veins.

RESULTS

Angiography identified the following LVS veins: (1) LV annular branch of the great cardiac vein (GCV) (19/53); (2) septal (rightward) branches of the anterior ventricular vein (AIV) (53/53); and (3) diagonal branches of the AIV (51/53). Collateral connections between LVS veins and outflow, conus, and retroaortic veins were common. VEA was delivered to target arrhythmias in 38 of 53 septal, 6 of 53 annular, and 2 of 53 diagonal veins. vCTA identified LVS veins (range 1-5) in a similar distribution. GCV-AIV transition could either form an angle close to the left main artery bifurcation (n = 16; 88° ± 13°) or cut diagonally (n = 36; 133°±12°) (P ≤.001). Twenty-one patients had LV annular vein. In 28 patients only septal LVS veins were visualized in vCTA, in 2 patients only diagonal veins and in 22 patients both septal and diagonal veins were seen. In 39 patients the LVS veins reached the outflow tracts and their vicinity.

CONCLUSION

We provide a systematic atlas and nomenclature of LVS veins related to arrhythmogenic substrates. vCTA can be useful for noninvasive evaluation of LVS veins before ethanol ablation.

Sleep Apnea and Atrial Fibrillation: Role of the Cardiac Autonomic Nervous System

Sleep apnea is highly associated with atrial fibrillation (AF), and both diseases are highly prevalent in the United States. The mechanistic underpinnings that contribute to their association remain uncertain, but numerous possible mechanisms have been proposed, including dysfunction of the cardiac autonomic nervous system (ANS). Studies have reported that apnea induces hyperactivity of the ANS, leading to increases in AF susceptibility. This review compiles the latest evidence on the role of the ANS in sleep-apnea-induced AF.

Alcohol Ablation for Ventricular Tachycardia

Catheter-based radiofrequency (RF) ablation is an effective, well-established therapy for ventricular tachycardia (VT). However, a large number of patients still have recurrences, particularly those with substrates arising from intramural locations that are inaccessible through endo- or epicardial catheter approaches. Several unconventional ablation techniques have been proposed to treat RF-refractory VT, including transarterial coronary ethanol ablation and retrograde coronary venous ethanol ablation. We review the evidence regarding the mechanisms, procedural aspects, and alcohol ablation outcomes for ventricular arrhythmias.

Atrial Fibrillation Ablation Using Vein of Marshall Ethanol Infusion

Catheter ablation has become a cornerstone treatment for atrial fibrillation (AF). Pulmonary vein isolation is the accepted approach for paroxysmal AF ablation, but it is less effective for persistent AF. The vein of Marshall (VOM) is located in the epicardial left atrium and can be a source of AF triggers as well as a tract for autonomic nerves. It directly communicates with the underlying myocardium, including the left atrial ridge and the posterior mitral isthmus. This review discusses the latest evidence regarding the mechanisms, procedural aspects, and outcomes of VOM ethanol infusion when used as an adjunct to pulmonary vein isolation in patients with persistent AF.

Determinants of outcome impact of vein of Marshall ethanol infusion when added to catheter ablation of persistent atrial fibrillation: A secondary analysis of the VENUS randomized clinical trial

BACKGROUND

The Vein of Marshall Ethanol for Untreated Persistent AF (VENUS) trial demonstrated that adding vein of Marshall (VOM) ethanol infusion to catheter ablation (CA) improves ablation outcomes in persistent atrial fibrillation (AF). There was significant heterogeneity in the impact of VOM ethanol infusion on rhythm control.

OBJECTIVE

The purpose of this study was to assess the association between outcomes and (1) achievement of bidirectional perimitral conduction block and (2) procedural volume.

METHODS

The VENUS trial randomized patients with persistent AF (N = 343) to CA combined with VOM ethanol or CA alone. The primary outcome (freedom from AF or atrial tachycardia [AT] lasting longer than 30 seconds after a single procedure) was analyzed by 2 categories: (1) successful vs no perimitral block and (2) high- (>20 patients enrolled) vs low-volume centers.

RESULTS

In patients with perimitral block, the primary outcome was reached 54.3% after VOM-CA and 37% after CA alone (P = .01). Among patients without perimitral block, freedom from AF/AT was 34.0% after VOM-CA and 37.0% after CA (P = .583). In high-volume centers, the primary outcome was reached in 56.4% after VOM-CA and 40.2% after CA (P = .01). In low-volume centers, freedom from AF/AT was 30.77% after VOM-CA and 32.61% after CA (P = .84). In patients with successful perimitral block from high-volume centers, the primary outcome was reached in 59% after VOM-CA and 39.1% after CA (P = .01). Tests for interaction were significant (P = .002 for perimitral block and P = .04 for center volume).

CONCLUSION

Adding VOM ethanol infusion to CA has a greater impact on outcomes when associated with perimitral block and performed in high-volume centers. Perimitral block should be part of the VOM procedure.

Incidence and Prognosis of Pericarditis After ST-Elevation Myocardial Infarction (from the Acute Coronary Syndrome Israeli Survey 2000 to 2013 Registry Database)

There are scarce contemporary data regarding the incidence and prognosis of early postmyocardial infarction pericarditis (PMIP). Thus, we retrospectively analyzed 6,282 patients with ST-segment elevation myocardial infarction (STEMI) enrolled with known PMIP status in the Acute Coronary Syndrome Israeli Survey 2000 to 2013 registry. The primary outcome was the composite of all-cause mortality, nonfatal myocardial infarction, cerebrovascular event, stent thrombosis, or revascularization. The secondary outcomes were mortality and length of stay during the acute hospitalization. Overall, 76 patients with STEMI had PMIP (1.2%). PMIP incidence gradually decreased from 170 per 10,000 in 2000 to 110 per 10,000 in 2013, respectively (35% reduction, p for trend = 0.035). Patients with PMIP were younger (median 58.0 vs 61.0; p = 0.045), had less hypertension, higher cardiac biomarkers, and more frequently reduced left ventricular ejection fraction (87.0% vs 67.0%; p = 0.001). Patients with PMIP had longer time to reperfusion (225 minutes vs 183 minutes; p = 0.016) and length of stay (7.0 vs 5.0 days; p < 0.001). The composite end point occurred similarly in patients with and without PMIP (10.5% vs 13.2%, respectively). There was no significant difference in 30-day, 1-year, and 5-year survival. In conclusion, PMIP is a relatively rare complication of STEMI in the coronary reperfusion era, portends worse short-term but not long-term outcomes, and is associated with bigger infarct size.

Transcatheter versus surgical aortic valve replacement in patients at low surgical risk: A meta-analysis of randomized trials and propensity score matched observational studies

BACKGROUND

Although transcatheter aortic valve replacement (TAVR) is officially indicated for high risk aortic stenosis (AS) patients, the procedure is increasingly being performed in patients who are not at high surgical risk, including a substantial number of low risk patients. However, data on the benefit of TAVR in this patient population is limited.

METHODS

We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) and observational studies with propensity score matching (PSM) of TAVR versus surgical aortic valve replacement (SAVR) in patients who are at low surgical risk. The primary outcome was all-cause mortality. The secondary outcomes included stroke, myocardial infarction, bleeding, and various procedural complications.

RESULTS

Six studies (2 RCTs and 4 PSM studies) totaling 3,484 patients were included. Follow-up ranged from 3 months to 3 years (median 2 years). The short-term mortality was similar with either TAVR or SAVR (2.2% for TAVR and 2.6% for SAVR, RR 0.89, 95% CI 0.56-1.41, P = 0.62), however, TAVR was associated with increased risk for intermediate-term mortality (17.2% for TAVR and 12.7% for SAVR, RR 1.45, 95% CI 1.11-1.89, P = 0.006). In terms of periprocedural complications, TAVR was associated with reduced risk for bleeding and renal failure and an increase in vascular complications and Pacemaker implantation.

CONCLUSIONS

In patients who are at low surgical risk, TAVR seems to be associated with increased mortality risk. Until more data in this population is available, SAVR should remain the treatment of choice for these patients.

Transcatheter Aortic Valve Implantation Futility Risk Model Development and Validation Among Treated Patients With Aortic Stenosis

Risk-benefit assessment for transcatheter aortic valve implantation (TAVI) is still evolving. A sizeable group of patients do not fully benefit from intervention despite a technically successful procedure. All patients who underwent TAVI with device success and with no Valve Academic Research Consortium (VARC)-2 defined complications were included. Various demographic data, clinical details, and echocardiographic findings were examined. The outcome was defined as 1-year composite of mortality, stroke, lack of functional-class improvement (by New York Heart Association class), and readmissions (≥1 month after the procedure). Logistic regression was used to fit the prediction model. We used a 10-fold cross-validation to validate our results. Of 543 patients, 435 met the inclusion criteria. The mean age was 82 (±6.5) years, 43% were men, and the mean Society of Thoracic Surgeons score was 6.6 (±4.7). At 1 year, 66 of 435 patients (15%) experienced the study end point. The final logistic regression model included diabetes, baseline New York Heart Association functional class, diastolic dysfunction, need for diuretics, mean gradient, hemoglobin level, and creatinine level. The area under the curve was 0.73 and was reduced to 0.71 after validation, with a 97% specificity using a single cutoff. Dividing to low-, medium-, and high-risk groups for futility produced a corresponding prevalence of 6%, 19%, and 59% futility. A web application for the prediction model was developed and provided. In conclusion, this prediction score may provide an important insight and may facilitate identification of patients who, despite a technically successful and uncomplicated procedure, have risk that may outweigh the benefit of a contemplated TAVI.

Prognosis of STEMI Patients with Multi-Vessel Disease Undergoing Culprit-Only PCI without Significant Residual Ischemia on Non-Invasive Stress Testing

Aims

In about 50–80% of ST-segment elevation myocardial infarction (STEMI) patients there is significant atherosclerotic disease in other coronary arteries in addition to the culprit vessel. There is substantial controversy as to the optimal revascularization approach in these patients. We sought to compare the outcomes of STEMI patients with multi-vessel disease (MVD) treated with culprit-only primary percutaneous coronary intervention (PPCI) without significant ischemia on subsequent non-invasive testing, to those of STEMI patients with single-vessel disease (SVD).

Methods and Results

Between 2001–2010, 1,540 consecutive patients treated with primary PCI for STEMI were prospectively observed and entered into a comprehensive clinical database. The primary end point was a composite of major adverse cardiac events (MACE), consisting of mortality, re-infarction and revascularization within 1 and 3 years following PPCI (excluding events occurring during the first 30 days). Patients with cardiogenic shock were excluded. The study included 720 patients with SVD and 185 patients with MVD who underwent culprit-only PPCI and had no residual ischemia on subsequent non-invasive stress testing. Patients with MVD were older, more likely to have hypertension or previous MI and less likely to be smokers and present with anterior MI than patients with SVD. One and 3-year MACE rates were similar between the groups. On cox proportional-hazards regression MVD without residual ischemia was not independently associated with MACE and its components.

Conclusions

STEMI patients with MVD treated with culprit only-PCI without significant residual ischemia on non-invasive stress testing appear to have similar prognosis to STEMI patients with SVD.

Antibiotics for asymptomatic bacteriuria

BACKGROUND

Asymptomatic bacteriuria is commonly detected in women aged up to 60 years, patients with diabetes, and the elderly. The benefit of antibiotic treatment for this condition is controversial.

OBJECTIVES

To assess the effectiveness and safety of antibiotics treatment for asymptomatic bacteriuria in adults. Specific objectives were to assess 1) the effectiveness of antibiotics for preventing development of symptomatic UTI, UTI-related complications, overall mortality, UTI-related mortality, and resolution of bacteriuria; 2) the development of resistance to antibiotic treatment by comparing resistance of grown bacteria in urine before and after therapy; and 3) the frequency of adverse events.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register up to 24 February 2015 through contact with the Trials' Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing antibiotics to placebo or no treatment for asymptomatic bacteriuria in adults were included. The outcomes of interest were the development of symptomatic urinary tract infection (UTI), complications, death, any adverse event, development of antibiotic resistance, bacteriological cure, and decline in kidney function.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed study quality. Statistical analyses were performed using the random effects model and the results expressed as risk ratios (RR) with 95% confidence intervals (CI).

MAIN RESULTS

We included nine studies (1614 participants) in this review. Symptomatic UTI (RR 1.11, 95% CI 0.51 to 2.43), complications (RR 0.78, 95% CI 0. 35 to 1.74), and death (RR 0.99, 95% CI 0.70 to 1.41) were similar between the antibiotic and placebo or no treatment arms. Antibiotics were more effective for bacteriological cure (RR 2.32, 95% CI 1.11 to 4.83) but also more adverse events developed in this group (RR 3.77, 95% CI 1.40 to 10.15). No decline in the kidney function was observed across the studies; minimal data were available on the emergence of resistant strains after antimicrobial treatment.The included studies were of medium and high quality, used different treatments for different durations of treatment and follow-up, different populations, but this did not appear to influence the results of review.

AUTHORS' CONCLUSIONS

No differences were observed between antibiotics versus no treatment of asymptomatic bacteriuria for the development of symptomatic UTI, complications or death. Antibiotics were superior to no treatment for the bacteriological cure but with significantly more adverse events. There was no clinical benefit from treating asymptomatic bacteriuria in the studies included in this review.

Efficacy and safety of chloramphenicol: joining the revival of old antibiotics? Systematic review and meta-analysis of randomized controlled trials

OBJECTIVES

Chloramphenicol is an old broad-spectrum antibiotic. We assessed its efficacy and safety.

METHODS

This was a systematic review and meta-analysis. Electronic databases were searched to identify randomized controlled trials (RCTs) that assessed patients, of any age, with systemic bacterial infections that can cause sepsis and compared chloramphenicol alone versus other antibiotics. No restrictions on the date of publication, language or publication status were applied. The primary outcome assessed was overall mortality.

RESULTS

Sixty-six RCTs fulfilled the inclusion criteria, and these included 9711 patients. We found a higher mortality with chloramphenicol for respiratory tract infections [risk ratio (RR) 1.40, 95% CI 1.00-1.97] and meningitis (RR 1.27, 95% CI 1.00-1.60), both without heterogeneity. The point estimate was similar for enteric fever, without statistical significance. No statistically significant difference was found between chloramphenicol and other antibiotics regarding treatment failure, except for enteric fever (RR 1.46, 95% CI 1.07-2.00, without heterogeneity). This difference derived mainly from studies comparing chloramphenicol with fluoroquinolones (RR 1.85, 95% CI 1.07-3.2). There were no statistically significant differences between chloramphenicol and other antibiotics in terms of adverse events, including haematological events, except for anaemia, which occurred more frequently with chloramphenicol (RR 2.80, 95% CI 1.65-4.75, I(2) =0%), and gastrointestinal side effects, which were less frequent with chloramphenicol (RR 0.67, 95% CI 0.46-0.99, I(2) =0%). Many of the studies included were sponsored by pharmaceutical companies marketing the comparator drug to chloramphenicol, and this might have influenced the results.

CONCLUSIONS

Chloramphenicol cannot be recommended as a first-line treatment for respiratory tract infections, meningitis or enteric fever as alternatives are probably more effective. Chloramphenicol is as safe as treatment alternatives for short antibiotic courses. RCTs are needed to test this treatment against MDR organisms when better alternatives do not exist.

Beta lactam antibiotic monotherapy versus beta lactam-aminoglycoside antibiotic combination therapy for sepsis

BACKGROUND

Optimal antibiotic treatment for sepsis is imperative. Combining a beta lactam antibiotic with an aminoglycoside antibiotic may provide certain advantages over beta lactam monotherapy.

OBJECTIVES

Our objectives were to compare beta lactam monotherapy versus beta lactam-aminoglycoside combination therapy in patients with sepsis and to estimate the rate of adverse effects with each treatment regimen, including the development of bacterial resistance to antibiotics.

SEARCH METHODS

In this updated review, we searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11); MEDLINE (1966 to 4 November 2013); EMBASE (1980 to November 2013); LILACS (1982 to November 2013); and conference proceedings of the Interscience Conference of Antimicrobial Agents and Chemotherapy (1995 to 2013). We scanned citations of all identified studies and contacted all corresponding authors. In our previous review, we searched the databases to July 2004.

SELECTION CRITERIA

We included randomized and quasi-randomized trials comparing any beta lactam monotherapy versus any combination of a beta lactam with an aminoglycoside for sepsis.

DATA COLLECTION AND ANALYSIS

The primary outcome was all-cause mortality. Secondary outcomes included treatment failure, superinfections and adverse events. Two review authors independently collected data. We pooled risk ratios (RRs) with 95% confidence intervals (CIs) using the fixed-effect model. We extracted outcomes by intention-to-treat analysis whenever possible.

MAIN RESULTS

We included 69 trials that randomly assigned 7863 participants. Twenty-two trials compared the same beta lactam in both study arms, while the remaining trials compared different beta lactams using a broader-spectrum beta lactam in the monotherapy arm. In trials comparing the same beta lactam, we observed no difference between study groups with regard to all-cause mortality (RR 0.97, 95% CI 0.73 to 1.30) and clinical failure (RR 1.11, 95% CI 0.95 to 1.29). In studies comparing different beta lactams, we observed a trend for benefit with monotherapy for all-cause mortality (RR 0.85, 95% CI 0.71 to 1.01) and a significant advantage for clinical failure (RR 0.75, 95% CI 0.67 to 0.84). No significant disparities emerged from subgroup and sensitivity analyses, including assessment of participants with Gram-negative infection. The subgroup of Pseudomonas aeruginosa infections was underpowered to examine effects. Results for mortality were classified as low quality of evidence mainly as the result of imprecision. Results for failure were classified as very low quality of evidence because of indirectness of the outcome and possible detection bias in non-blinded trials. We detected no differences in the rate of development of resistance. Nephrotoxicity was significantly less frequent with monotherapy (RR 0.30, 95% CI 0.23 to 0.39). We found no heterogeneity for all these comparisons.We included a small subset of studies addressing participants with Gram-positive infection, mainly endocarditis. We identified no difference between monotherapy and combination therapy in these studies.

AUTHORS' CONCLUSIONS

The addition of an aminoglycoside to beta lactams for sepsis should be discouraged. All-cause mortality rates are unchanged. Combination treatment carries a significant risk of nephrotoxicity.

Macrolides vs. quinolones for community-acquired pneumonia: meta-analysis of randomized controlled trials

The relative efficacy, safety and ecological implications of macrolides vs. quinolones in the treatment of community-acquired pneumonia (CAP) are debatable. We performed a systematic review and meta-analysis of randomized controlled trials comparing any macrolide vs. any quinolone for the treatment of CAP among adult inpatients or outpatients, as monotherapy or both in combination with a beta-lactam. We did not limit inclusion by pneumonia severity, publication status, language or date of publication. The primary outcomes assessed were 30-day all-cause mortality and treatment failure. Two authors independently extracted the data. Fixed effect meta-analysis of risk ratios (RRs) with 95% confidence intervals was performed. Sixteen trials (4989 patients) fulfilling inclusion criteria were identified, mostly assessing outpatients with mild to moderate CAP. All-cause mortality was not significantly different for macrolides vs. quinolones, RR 1.03 (0.63-1.68, seven trials), with a low event rate (2%). Treatment failure was significantly lower with quinolones, RR 0.78 (0.67-0.91, 16 trials). The definition of failure used in the primary studies was not clearly representative of patients' benefit. Microbiological failure was lower with quinolones, RR 0.63 (0.49-0.81, 13 trials). All adverse events, adverse events requiring discontinuation and any premature antibiotic discontinuation were significantly more frequent with macrolides, mainly on account of gastrointestinal adverse events. Resistance development was not assessed in the trials. Randomized controlled trials show an advantage of quinolones in the treatment of CAP with regard to clinical cure without need for antibiotic modification at end of treatment and gastrointestinal adverse events. The clinical significance of this advantage is unclear.

Antibiotic prophylaxis in cardiac surgery: systematic review and meta-analysis

BACKGROUND

Antibiotic prophylaxis is recommended in cardiac surgery. Current debate concerns the type of antibiotic(s), dosing and the duration of prophylaxis.

METHODS

Systematic review of randomized controlled trials comparing one antibiotic regimen versus another in cardiac surgery. We searched The Cochrane Library, PubMed, LILACS, conference proceedings and bibliographies. Two reviewers independently extracted the data. The primary outcome was deep sternal wound infections (DSWIs). Meta-analysis was performed using the Mantel-Haenszel fixed-effect method. Risk ratios (RRs) with 95% confidence intervals (95% CIs) are reported.

RESULTS

Fifty-nine trials were included. There were no significant differences in DSWI or all other categories of surgical site infections (SSIs) for antibiotic prophylaxis with β-lactams comprising a Gram-negative spectrum of coverage versus prophylaxis targeting Gram-positive bacteria, but the former led to a significantly lower rate of post-operative pneumonia (RR 0.68, 95% CI 0.51-0.90) and all-cause mortality (RR 0.66, 95% CI 0.47-0.92). In trials comparing different antibiotic regimens for different durations, prophylaxis duration of ≤24 h post-operation led to higher rates of DSWI (RR 1.83, 95% CI 1.25-2.66), any sternal SSI, surgical interventions for SSI and endocarditis compared with longer duration prophylaxis. There was no advantage of regimens lasting >48 h post-operation. In the comparison of glycopeptides versus β-lactams, an advantage of glycopeptides was observed when comparators were given for similar duration and for β-lactams when given for a longer duration than the glycopeptides. There was no significant advantage of high antibiotic dosing.

CONCLUSIONS

Evidence supports second- or third-generation cephalosporins for cardiac surgery prophylaxis and points at a possible advantage of prophylaxis prolongation up to 48 h post-operatively.

Efficacy and safety of tigecycline: a systematic review and meta-analysis

BACKGROUND

Tigecycline is a novel glycylcycline that exhibits broad-spectrum antibacterial activity. Recently, the US FDA issued a warning concerning increased mortality with tigecycline in randomized controlled trials (RCTs).

METHODS

We conducted a systematic review and meta-analysis of RCTs that compared tigecycline with any other antibiotic regimen for the treatment of any infection. A comprehensive search, without publication status or other restrictions, was conducted. The primary outcome was overall 30 day mortality. The secondary outcome included clinical and microbiological failure, superinfections and adverse events (AEs). The trials' risks of bias and their effects on results were assessed. Two reviewers independently extracted the data. Individual trials' relative risks (RRs) were pooled using a fixed effect meta-analysis.

RESULTS

Fifteen trials (7654 patients) were included. Overall mortality was higher with tigecycline compared with other regimens [RR 1.29, 95% confidence interval (CI) 1.02-1.64, without heterogeneity]. The type of infection assessed and the trials' reported risks of bias did not affect this result. Clinical failure was significantly higher with tigecycline (RR 1.16, 95% CI 1.06-1.27) and non-statistically significant higher rates of microbiological failure were demonstrated (RR 1.13, 95% CI 0.99-1.30). Development of septic shock was significantly more frequent with tigecycline (RR 7.01, 95% CI 1.27-38.66). Superinfections were significantly more common with tigecycline and so were AEs, including all AEs and AEs requiring discontinuation.

CONCLUSIONS

In the light of the increased mortality, probably explained by decreased clinical and microbiological efficacy, clinicians should avoid tigecycline monotherapy in the treatment of severe infections and reserve it as a last-resort drug.