D-dimer for the prediction of left atrial appendage thrombosis: daydream or reality? A meta-analysis

Introduction

Left atrial appendage thrombosis (LAAT) is a dangerous condition that mainly affects patients with atrial fibrillation (AF) or those with mitral stenosis (MS), increasing their risk of stroke. Transesophageal echocardiography (TEE) is the gold standard for the diagnosis of LAAT but some technical issues and the suboptimal sensitivity in identifying small thrombi, especially within a side lobe, can limit its clinical usefulness. Reliable non-invasive diagnostic methods could be useful in clinical practice. D-dimer, a fibrin degradation product already commonly used in the diagnostic work-up of conditions such as venous thromboembolism, may have a role as a non-invasive marker of LAAT.

Purpose

To evaluate the diagnostic performance of D-dimer for the detection of LAAT in patients with AF and/or MS, using TEE as the reference standard.

Methods

We searched the literature for studies that evaluated the ability of D-dimer to predict LAAT. For each study a 2x2 table of D-dimer positivity and LAAT presence was constructed. Sensitivity, specificity, positive predictive value and negative predictive value were calculated. Considering the different diagnostic thresholds used in the included studies, the overall sensitivity and specificity were calculated using a hierarchal summary receiver operating characteristic (HSROC) model and a SROC curve was generated.

Results

6 studies, evaluating 1380 patients of whom 154 had LAAT, were included in the analysis. The prevalence of LAAT in the studies ranged from 9% to 26%, with a median of 12%. The mean age was 60±13 years, 63% were male. The mean left atrial diameter was 43±3 mm. The D-dimer diagnostic threshold ranged from 200 mcg/l to 1150 mcg/l. The overall sensitivity calculated with the HSROC model was 85%±28% and the overall specificity was 82%±29%. The negative predictive value was 98%. Figure 1 shows the summary ROC curve: individual studies are depicted by a clear circle; the red circle marks the pooled sensitivity and specificity across the 6 studies. The red dot-dashed-curve marks the boundary of the 95% credible region for the pooled estimates of sensitivity and specificity.

Conclusions

Our analysis shows that D-dimer has a good diagnostic performance with a very high negative predictive value for LAAT and therefore it might be of clinical aid for ruling out the presence of LAAT in patients with AF and/or MS. Further studies are needed to determine the best diagnostic threshold.

Figure 1

Funding Acknowledgement

Type of funding source: None

P569Efficacy and safety of direct Xa oral inhibitors versus warfarin in patients with atrial fibrillation and cancer: a meta-analysis of randomized controlled trials

Background

Patients with cancer are at higher risk of atrial fibrillation (AF) compared with the general population. Furthermore, cancer per se and anti-cancer treatments have been associated with thromboembolic complications and increased bleeding risk. Considering that only 12% of cancer patients can achieve a stable International Normalized Ratio target and the frequent need for invasive procedures, warfarin is not an ideal option. Direct oral anticoagulants may theoretically represent a valid alternative although their use in this population has been scarcely investigated.

Purpose

To compare efficacy and safety of direct oral Xa inhibitors (DOXaI) versus warfarin in patients with atrial fibrillation and cancer.

Methods

We searched electronic databases for randomized controlled trials (RCTs) that analyzed the use of DOXaI versus warfarin in patients with AF and cancer. The primary efficacy outcome was stroke or systemic embolism (SE). The secondary efficacy outcomes were ischemic stroke, myocardial infarction and all-cause death. The primary safety outcome was major bleeding; secondary safety outcomes were major or clinically relevant non-major bleeding, intracranial bleeding and any bleeding. The net clinical benefit was estimated as the composite of the two primary outcomes. A sensitivity analysis was performed to better define the incidence of these outcomes in patients with active cancer. The statistical software ProMeta 3 was used to estimate the risk ratio with a random-effect model.

Results

3 RCTs counting a total of 3029 cancer patients (1682 on DOXaI and 1347 on warfarin), 1354  of whom with active cancer (856 on DOXaI and 502 on warfarin), were included in the analysis. Mean age was 75.6 ± 1.2 years, and 32% were female. Mean follow-up period was 2.2 ± 0.6 years. The most common cancer sites were prostate (23%), gastrointestinal tract (22.2%), breast (12.1%) and genitourinary tract (10.6%). The mean CHADS2 score was 2.9 ± 0.6 and the mean HAS-BLED score was 2.6 ± 0.4.

There were no significant differences in the risk of stroke or SE (RR 0.76; 95% CI 0.52-1.10) as well as for all the other secondary efficacy outcomes. DOXaI significantly reduced the incidence of major bleeding in the overall cancer population (RR 0.79; 95% CI 0.63-0.99; p = 0.039); this finding was consistent also in patients with active cancer (RR 0.79; 95% CI 0.59-1.05) although the effect was not statistically significant.  DOXaI also significantly reduced intracranial bleeding in overall cancer population (RR 0.12; 95% CI 0.02-0.63; p = 0.013) and any bleeding in active cancer patients (RR 0.87; 95% CI 0.77-0.98; p = 0.026). Furthermore, DOXaI significantly reduced the composite endpoints of major bleeding and stroke or SE in overall cancer population (RR 0.78; 95% CI 0.64-0.94; p = 0.008).

Conclusions

Our metanalysis shows that, in patients with atrial fibrillation and cancer, DOXaI are safer and have a similar efficacy compared with warfarin.

Abstract Figure. Primary efficacy and safety outcomes

P1915Time to freeze - An updated meta-analysis on the efficacy and safety of cryoballoon versus radiofrequency ablation for atrial fibrillation

Background and aim

Pulmonary vein isolation (PVI) is the cornerstone of atrial fibrillation (AF) ablation. Its efficacy to prevent recurrent arrhythmias in patients nonresponsive to antiarrhythmic drugs is proven. This procedure has a higher efficacy rate in patients with paroxysmal AF (PAF) compared with persistent AF (sustained AF - SAF). Radiofrequency (RF) ablation represents a standard of care for PVI, while, cryoballoon (CB) ablation has emerged as a valid alternative therapy. The aim of the present meta-analysis was to explore the comparative efficacy, and safety of CB compared with RF ablation for AF.

Methods

We searched PubMed and EMBASE for studies that investigated the comparative efficacy and safety of CB versus RF ablation for AF. The efficacy outcome was AF recurrence after the procedure. The safety outcomes were: incidence of pericardial effusion or cardiac tamponade, permanent phrenic nerve palsy, transient phrenic nerve palsy, vascular complications and major bleedings. The performance outcomes were: procedural time and fluoroscopy time. Random-effects Risk Ratios (RRs) were estimated using a DerSimonian-Laird model. Two subgroup sensitivity analyses were performed to stratify the result on the efficacy outcome according to type of AF (PAF versus SAF) and study design (randomized clinical trial (RCT) versus observational study (OS)).

Results

12 RCT and 34 OS were included in the analysis (n=13103). Mean follow-up was 14±6 months. 37 studies included only patients with PAF, while, 2 studies included only patients with SAF and the remaining 7 studies included both patients with SAF or PAF. Overall, CB ablation reduced the incidence of AF recurrence compared with RF ablation (RR 0.85; 95% CI 0.77–0.95; P=0.002 - Figure). However, this reduction was not consistent in the RCT subgroup (RR 0.90; 95% CI 0.72–1.13) and it was marginally non-significant in the SAF subgroup (RR 0.76; 95% CI 0.57–1.01). Regarding the safety outcomes, although CB had a significantly higher rate of transient nerve palsy compared with RF procedure (RR 7.46; 95% CI 4.67–11.90) this difference became non-significant when considering permanent phrenic nerve palsy (RR 1.24; 95% CI 0.66–2.34). Moreover, CB was related to a lower incidence of pericardial effusion or cardiac tamponade compared with RF (RR 0.51; 95% CI 0.37–0.69) and there was no significant difference in vascular complications or major bleedings between the two strategies. Focusing on performance outcomes, CB ablation had a shorter procedural time compared with RF (mean difference −20 minutes; 95% CI −30 to −10; P<0.001); whereas, there was no significant difference in fluoroscopy time between the two.

CB vs. RF in preventing AF recurrence

Conclusions

This large study level meta-analysis demonstrates that CB is at least as effective as RF ablation in preventing arrhythmic recurrence both in patients with PAF and SAF. Moreover, our study suggests that CB has a safer profile and shorter procedural time compared with RF ablation.

A gas chromatography-mass spectrometry untargeted metabolomics approach to discriminate Fiore Sardo cheese produced from raw or thermized ovine milk

Thermization is a sub-pasteurization heat treatment of cheese milk (at 57-68°C for 15-30 s) aimed to reduce the number of undesirable microbial contaminants with reduced heat damage to the indigenous milk enzymes. In this work, the effects of milk thermization on the compositional parameters, proteolysis indices, free fatty acid levels, and low molecular weight metabolite profiles of ovine cheese were studied. Cheese samples at different ripening stages and produced in 2 different periods of the year were analyzed. While the effects of milk thermization on cheese macro-compositional parameters and free fatty acid levels were not evident due to the predominant effects of milk seasonality and cheese ripening stage, the gas chromatography-mass spectrometry based metabolomics approach of ovine cheese produced from raw and thermized milk highlighted strong differences at the metabolite level. Discriminant analysis applied to gas chromatography-mass spectrometry data provided an excellent classification model where cheese samples were correctly classified as produced from raw or thermized milk. The metabolites that mostly changed due to the thermization process belonged to the classes of free amino acids and saccharides. Gas chromatography-mass spectrometry-based metabolomics has proven to be a valid tool to study the effect of mild heat treatments on the polar metabolite profile in ovine cheese.

Statin use and risk of new-onset diabetes: A meta-analysis of observational studies

BACKGROUND AND AIMS

Meta-analyses of randomized control trials investigating the association between incident diabetes and statin use showed an increased risk of new-onset diabetes (NOD) from 9% to 13% associated with statins. However, short follow-up period, unpowered sample size, and lack of pre-specified diagnostic criteria for diabetes detection could be responsible of an underestimation of this risk. We conducted a meta-analysis of published observational studies to evaluate the association between statins use and risk of NOD.

METHODS AND RESULTS

PubMed, EMBASE and MEDLINE databases were searched from inception to June 30, 2016 for cohort and case-control studies with risk of NOD in users vs nonusers, on ≥1000 subjects followed-up for ≥1 year. Two review authors assessed study eligibility and risk of bias and undertook data extraction independently. Pooled estimates were calculated by a random-effects model and between-study heterogeneity was tested and measured by I² index. Furthermore, stratified analyses and the evaluation of publication bias were performed. Finally, the meta-analysis included 20 studies, 18 cohort and 2 case-control studies. Overall, NOD risk was higher in statin users than nonusers (RR 1.44; 95% CI 1.31-1.58). High between-study heterogeneity (I² = 97%) was found. Estimates for all single statins showed a class effect, from rosuvastatin (RR 1.61; 1.30-1.98) to simvastatin (RR 1.38; 1.19-1.61).

CONCLUSIONS

The present meta-analysis confirms and reinforces the evidence of a diabetogenic effect by statins utilization. These observations confirm the need of a rigorous monitoring of patients taking statins, in particular pre-diabetic patients or patients presenting with established risk factors for diabetes.

Pentraxin 3 (PTX3) plasma levels and carotid intima media thickness progression in the general population

BACKGROUND AND AIM

Pentraxin 3 (PTX3) is an essential component of the humoral arm of innate immunity and, like C-reactive protein, is independently associated with the risk of developing vascular events. Aim of this study was to investigate, in two large population-based surveys, the Bruneck Study and the PLIC Study, whether PTX3 plasma levels predict the progression of common carotid artery intima-media thickness (CCA-IMT), a surrogate marker of atherosclerosis, in the general population during 5 or 6 years of follow-up.

RESULTS

In the Bruneck Study, PTX3 plasma levels did not predict a faster progression of CCA-IMT either in the carotid artery or in the femoral artery. This finding was confirmed in the PLIC Study where subjects within the highest tertile of PTX3 did not show an increased progression of CCA-IMT. PTX3 plasma levels were also not associated with the fastest maximum IMT progression. In summary, in more than 2400 subjects from the general population, PTX3 plasma level is neither an independent predictor of progression of subclinical atherosclerosis in different arterial territories, including carotid and femoral arteries nor of incident cardiovascular events.

CONCLUSION

These findings support the relevance of investigating the predictive value of PTX3 plasma levels only in specific settings, like overt CVD, heart failure or acute myocardial infarction.

Large temperature dependence of the number of carriers in co-doped BaFe(2)As(2)

Using angle-resolved photoemission spectroscopy, we study the evolution of the number of carriers in Ba(Fe(1-x)Co(x))(2)As(2) as a function of Co content and temperature. We show that there is a k-dependent energy shift compared to density functional calculations, which is large below 100 K at low Co contents and reduces the volume of hole and electron pockets by a factor 2. This k shift becomes negligible at high Co content and could be due to interband charge or spin fluctuations. We further reveal that the bands shift with temperature, changing significantly the number of carriers they contain (up to 50%). We explain this evolution by thermal excitations of carriers among the narrow bands, possibly combined with a temperature evolution of the k-dependent fluctuations.

Low-energy models for correlated materials: bandwidth renormalization from Coulombic screening

We provide a prescription for constructing Hamiltonians representing the low-energy physics of correlated electron materials with dynamically screened Coulomb interactions. The key feature is a renormalization of the hopping and hybridization parameters by the processes that lead to the dynamical screening. The renormalization is shown to be non-negligible for various classes of correlated electron materials. The bandwidth reduction effect is necessary for connecting models to materials behavior and for making quantitative predictions for low-energy properties of solids.

How many patients need statin treatment in a low-cardiovascular-risk country? Low-density lipoprotein-cholesterol target and distance from target distribution in an Italian cohort

BACKGROUND AND AIM

To assess cardiovascular risk distribution, distribution of individual low-density lipoprotein (LDL)-cholesterol target and distance of LDL cholesterol from the target in a representative sample of the Italian population.

METHODS AND RESULTS

Cross-sectional, population-based study of a representative sample of the Italian adult population, comprising 5458 individuals (from 40 to 79 years of age, both sexes) from general practices in Italy. Of the subjects, 65.2% were in the low-cardiovascular-risk class, whereas 10.5%, 18.3% and 6.0% had moderate, high, and very high cardiovascular risk profiles, respectively; 8.2% of the subjects were treated with statins at enrolment. Of the cohort, 68.3% displayed LDL-cholesterol values below their LDL target, as calculated according to their individual risk profile. Among the 31.7% 'not at target', 42.3% were ≤ 15%, 44.3% were between 15% and 40% and 13.4% were >40% over their LDL target.

CONCLUSIONS

About two-thirds of adults in a low-cardiovascular-risk country, such as Italy, have LDL-cholesterol levels 'at target', as defined in current guidelines. Accordingly, the remaining subjects require a lifestyle or pharmacological intervention to reach their target; 24% of the total cohort, in detail, need to be treated with a statin (or to continue the prescribed statin treatment) to reach the proper LDL target. This type of data analysis might help to optimise resource allocation in preventive medicine.

Toll-like receptor signaling in amyotrophic lateral sclerosis spinal cord tissue

Increasing evidence indicates that inflammatory responses could play a critical role in the pathogenesis of motor neuron injury in amyotrophic lateral sclerosis (ALS). Recent findings have underlined the role of Toll-like receptors (TLRs) and the receptor for advanced glycation endproducts (RAGE) in the regulation of both innate and adaptive immunity in different pathologies associated with neuroinflammation. In the present study we investigated the expression and cellular distribution of TLR2, TLR4, RAGE and their endogenous ligand high mobility group box 1 (HMGB1) in the spinal cord of control (n=6) and sporadic ALS (n=12) patients. The immunohistochemical analysis of TLR2, TLR4 and RAGE showed increased expression in reactive glial cells in both gray (ventral horn) and white matter of ALS spinal cord. TLR2 was predominantly detected in cells of the microglia/macrophage lineage, whereas the TLR4 and RAGE was strongly expressed in astrocytes. Real-time quantitative PCR analysis confirmed the increased expression of both TLR2 and TLR4 and HMGB1 mRNA level in ALS patients. In ALS spinal cord, HMGB1 signal is increased in the cytoplasm of reactive glia, indicating a possible release of this molecule from glial cells. Our findings show increased expression of TLR2, TLR4, RAGE and HMGB1 in reactive glia in human ALS spinal cord, suggesting activation of the TLR/RAGE signaling pathways. The activation of these pathways may contribute to the progression of inflammation, resulting in motor neuron injury. In this context, future studies, using animal models, will be important to achieve a better understanding of these signaling pathways in ALS in view of the development of new therapeutic strategies.

Genetics of acute lung injury: past, present and future

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are major health problems worldwide. Critical care physicians have long recognized that there are patients who progress poorly despite therapy while others do unexpectedly better than it might be predicted. It is now well accepted that these responses might be related to variations in the genome. However, little is known about the genes that are responsible for susceptibility and outcome in ALI and ARDS. The search for genetic variants determining susceptibility and predicting outcome is still a developing field. The identification of important associations between genotype and clinical outcomes will have an impact on the development of more efficient genotype- or phenotype-guided therapies for patients with ALI/ARDS. Using this point of view, we will discuss some of the advances in genetic association studies in relation to the occurrence and severity of ALI/ARDS. In addition, we will also discuss the strategic and medical implications of using genetic testing to detect or predict the occurrence and prognosis of ALI/ARDS.

Issues affecting molecular staging in the management of patients with melanoma

Prediction of metastatic potential remains one of the main goals to be pursued in order to better assess the risk subgroups of patients with melanoma. Detection of occult melanoma cells in peripheral blood (circulating metastatic cells [CMC]) or in sentinel lymph nodes (sentinel node metastatic cells [SNMC]), could significantly contribute to better predict survival in melanoma patients. An overview of the numerous published studies indicate the existence of several drawbacks about either the reliability of the approaches for identification of occult melanoma cells or the clinical value of CMC and SNMC as prognostic factors among melanoma patients. In this sense, characterization of the molecular mechanisms involved in development and progression of melanoma (referred to as melanomagenesis) could contribute to better classify the different subsets of melanoma patients. Increasing evidence suggest that melanoma develops as a result of accumulated abnormalities in genetic pathways within the melanocytic lineage. The different molecular mechanisms may have separate roles or cooperate during all evolutionary phases of melanocytic tumourigenesis, generating different subsets of melanoma patients with distinct aggressiveness, clinical behaviour, and response to therapy. All these features associated with either the dissemination of occult metastatic cells or the melanomagenesis might be useful to adequately manage the melanoma patients with different prognosis as well as to better address the different melanoma subsets toward more appropriate therapeutic approaches.

Molecular alterations at chromosome 9p21 in melanocytic naevi and melanoma

BACKGROUND

The chromosome 9p21 and its CDKN locus, with the p16 tumour suppressor gene (CDKN2A), are recognized as the genomic regions involved in the pathogenesis of melanoma.

OBJECTIVES

To elucidate further the role of such regions during the different phases of melanocytic tumorigenesis.

METHODS

Tissue sections from naevi, primary and metastatic melanomas were investigated by fluorescence in situ hybridization for allelic loss at the 9p21 chromosome and by immunochemistry for p16CDKN2A expression.

RESULTS

Dysplastic naevi and primary or secondary melanomas were found to carry hemizygous deletions within the entire 9p21 region at similar frequencies (varying from 55% to 62%). Allelic deletion spanning the CDKN locus was observed at significantly increased rates moving from early (7%) to advanced (28%) primary melanomas and to secondary melanoma lesions (37%) (P=0.018). Also, inactivation of the p16 gene (CDKN2A) was absent in naevi and present at steadily increasing rates moving from primary melanomas (7% early lesions to 17% advanced lesions) to melanoma metastases (62%) (P=0.004).

CONCLUSIONS

Our findings indicate that, in a model of sequential accumulation of genetic alterations, 9p21 deletions may play a role in melanocytic transformation and tumour initiation whereas rearrangements at the CDKN locus, and p16 gene (CDKN2A) inactivation may contribute to tumour progression.

Mitochondrial DNA assessment in adipocytes and peripheral blood mononuclear cells of HIV-infected patients with lipodystrophy according to a validated case definition

BACKGROUND

Several studies have compared mitochondrial DNA (mtDNA) content in tissue from HIV-1-infected patients on highly active antiretroviral therapy with and without evidence of lipodystrophy, the diagnosis of which was based on subjective clinical assessment.

OBJECTIVES

The aim of this study was to assess the utility of mtDNA quantification as a marker of HIV-associated lipodystrophy as diagnosed using a published validated case definition.

METHODS

We assessed mtDNA content in adipocytes from both thigh and lumbar subcutaneous adipose tissue (n=19), and in peripheral blood mononuclear cells (PBMC) (n=26), obtained from 26 HIV-1-infected patients classified as having lipodystrophy (n=17) or not having lipodystrophy (n=9) according to the validated definition derived from the Lipodystrophy Case Definition Study.

RESULTS

The adipocyte and PBMC mtDNA contents did not significantly differ between patients with and without lipodystrophy. Lipodystrophy patients had been treated for significantly longer times, especially with dideoxynucleoside analogues. In both groups, the thigh adipocyte mtDNA content was significantly greater than that of the lumbar region. When all patients were considered together, a statistically significant negative correlation was found between thigh adipocyte mtDNA content and stavudine treatment duration.

CONCLUSIONS

Longer exposure to dideoxynucleoside analogues was associated with lipodystrophy, and longer exposure to stavudine was correlated with lower mtDNA content in thigh adipocytes. However, a single measurement of adipocyte mtDNA content in this limited sample of patients could not distinguish between patients with and without clinical lipodystrophy. The observed variation in mtDNA content between different subcutaneous adipose tissue depots argues for harmonization of future studies regarding which depot to biopsy.

Serial RT-PCR detection of circulating tumour cells as a marker of disease progression in patients with malignant melanoma

18009

Background: Detection of circulating malignant cells (CMCs) through a reverse transcriptase-polymerase chain reaction (RT-PCR) assay seems to be a demonstration of systemic disease. We here evaluated the prognostic role of RT-PCR assays in serially-taken peripheral blood samples from patients with malignant melanoma (MM). Methods: One hundred forty-nine melanoma patients with disease stage ranging from I to III were consecutively collected in 1997. A multi-marker RT-PCR assay was used on peripheral blood samples obtained at time of diagnosis and every 6 months during the first two years of follow-up (total: 5 samples). Univariate and multivariate analyses were performed after 83 months of median follow-up. Results: Detection of at least one circulating mRNA marker was considered a signal of the presence of CMC (referred to as PCR-positive assay). A significant correlation was found between the rate of recurrences and the increasing number of PCR-positive assays (P = 0.007). Presence of CMC in a high number (≥2) of analysed blood samples was significantly correlated with a poor clinical outcome (disease-free survival: P = 0.019; overall survival: P = 0.034). Multivariate analysis revealed that presence of a PCR-positive status does play a role as independent prognostic factors for overall survival in melanoma patients, adding precision to the predictive power of the disease stage. Conclusions: Our findings indicated that serial RT-PCR assay may identify a high risk subset of melanoma patients with occult cancer cells constantly detected in blood circulation. Prolonged presence of CMCs seems to act as a surrogate marker of disease progression or a sign of more aggressive disease.

No significant financial relationships to disclose.

Greater and more rapid depletion of mitochondrial DNA in blood of patients treated with dual (zidovudine+didanosine or zidovudine+zalcitabine) vs. single (zidovudine) nucleoside reverse transcriptase inhibitors

BACKGROUND

Most toxicities associated with nucleoside analogue reverse transcriptase inhibitors (NRTIs) are thought to result from mitochondrial toxicity. These toxicities include peripheral neuropathy, pancreatitis, lactic acidosis, and peripheral lipoatrophy. Unfortunately, there are no validated laboratory markers for clinically assessing, let alone predicting, the onset of mitochondrial toxicity associated with NRTI therapy.

OBJECTIVES

To provide preliminary evidence of the potential clinical utility of an assay which has been developed for quantifying mitochondrial DNA (mtDNA) in clinical samples from HIV-infected patients.

METHODS

A single-tube duplex real-time DNA-nucleic acid sequence-based amplification (NASBA) assay (Mitox, Primagen, Amsterdam, the Netherlands) was used to quantify mtDNA in cryopreserved peripheral blood mononuclear cells (PBMC) obtained from HIV-1-infected patients during their prior participation in a randomized placebo-controlled trial comparing zidovudine (ZDV) monotherapy with combinations of ZDV plus either dideoxycytidine (ddC) or didanosine (ddI) (the Delta trial). Patients were antiretroviral naïve prior to entering the trial. Samples obtained during the initial 48 weeks of treatment were tested.

RESULTS

A significant decline of mtDNA, both in an intent-to-treat and in an as-treated analysis, was observed in patients treated with ZDV+ddC and ZDV+ddI, but not with ZDV alone, consistent with the results expected from the degree of mtDNA depletion described for each of these drugs in vitro.

CONCLUSIONS

This single-tube duplex real-time DNA-NASBA assay was shown to measure mtDNA accurately in PBMC. Treatment with a combination of two NRTIs was associated with greater reductions in mtDNA than obtained for ZDV monotherapy. The relevance of these results in predicting treatment toxicity requires further evaluation.