Obesity and Peripheral Artery Disease: Current Evidence and Controversies.

PURPOSE OF REVIEW: Obesity is a significant public health problem and a major risk factor for the development and progression of atherosclerosis and its cardiovascular manifestations. Lower extremity peripheral artery disease (PAD) affects 3%-10% of the Western population and, if left untreated, can lead to devastating outcomes with both an increased risk of morbidity and mortality. Interestingly, the association between obesity and PAD remains debatable. Whereas it is well known that PAD and obesity frequently overlap in the same patients, many studies have demonstrated a negative association between obesity and PAD and a protective effect of obesity on disease development and progression, a phenomenon described as the "obesity paradox." Possible mechanisms for this paradox may include genetic background, as assessed by mendelian randomization studies, adipose tissue dysfunction, and body fat distribution rather than adiposity, while other factors, such as sex, ethnicity, sarcopenia in the elderly population, or aggressive treatment of co-existing metabolic conditions in individuals with obesity compared to those with normal weight, could have some impact as well. RECENT RINDINGS: Few reviews and meta-analyses examining systematically the relationship between obesity and PAD exist. The impact of PAD development due to the presence of obesity remains largely controversial. However, the most current evidence, backed by a recent meta-analysis, suggests a potential protective role of a higher body mass index on PAD-related complications and mortality. In this review, we discuss the association between obesity and PAD development, progression, and management, and the potential pathophysiologic mechanisms linking the two diseases.

Meta-analysis Comparing Transradial Versus Transfemoral Secondary Access in Transcatheter Aortic Valve Implantation.

Up to a quarter of vascular complications during transcatheter aortic valve implantation (TAVI) result from secondary access via the femoral artery (FA). The radial artery (RA) is increasingly used as an alternative to the FA for secondary access in TAVI. Limited data exist on the outcomes of RA secondary access versus FA secondary access. We therefore conducted a systematic review and meta-analysis comparing secondary access sites. PubMed, EMBASE, Scopus, Cochrane library and CINAHL were searched systematically for studies comparing RA and FA as secondary access sites for TAVI. Primary outcomes of interest were vascular complications and major bleeding. Secondary outcomes included all-cause mortality, stroke and myocardial infarction (MI). Risk ratio (RR), standardized mean difference and corresponding 95% confidence intervals (CI) were calculated using a random effects model. Six observational studies comprising 6,373 patients (RA: 1,514, FA: 4,859) met inclusion criteria. Secondary access was utilized for aortography during valve deployment and to manage primary access site complications. Procedural characteristics were similar in both groups. RA was associated with a lower risk of major bleeding (RR: 0.51, 95% CI: 0.40 to 0.64, p <0.00001). No statistically significant difference was observed in the incidence of overall vascular complications, however, the risk of major vascular complications was lower with RA (RR: 0.45, 95% CI: 0.32 to 0.63, p <0.00001). The incidence of stroke and all-cause mortality was lower in RA, whereas no difference was observed in the risk of MI. In conclusion, our meta-analysis suggests that RA secondary access is associated with better outcomes for TAVI than FA.

Sex-Specific Outcomes in Cardiovascular Device Evaluations.

Background: Females have historically been underrepresented in cardiovascular device trials. As a result, differences in outcomes for males and females are not possible to be determined in subanalyses. Materials and Methods: Against a backdrop of troubling trends in cardiovascular outcomes for females, we provide a narrative review on the differences in outcomes observed in females undergoing device evaluations in multiple fields of cardiovascular medicine, including coronary revascularization, structural heart disease, and heart failure. We also review predictors of cardiovascular trial nonparticipation as it may provide avenues by which female enrollment in cardiovascular device trials can be improved. Results: Advances have been made in structural heart therapy, where female representation in transcatheter aortic valve replacement studies was nearly 50%. For other indications, coronary revascularization and heart failure, there was clearly a disparity in female recruitment. On average, female representation was 25% in major clinical trials evaluating drug eluting stents, implantable cardioverter defibrillators, cardiac resynchronization defibrillators, and ventricular assist devices. As a result, the best treatment recommendations for females in these fields are currently guided by outcomes evaluated primarily in males. Conclusions: Female enrollment in device clinical trials for coronary revascularization and heart failure has lagged, leaving uncertainty in making benefit/risk assessments of device therapy. The predictors of female nonparticipation in clinical trials can inform a comprehensive strategy to facilitate and enrich the enrollment of females in cardiovascular device trials. This is critical to ensure that sex differences can be considered in treatment selection, so that patients can receive the best available care.

Anti-Inflammatory Effects of HDL (High-Density Lipoprotein) in Macrophages Predominate Over Proinflammatory Effects in Atherosclerotic Plaques.

OBJECTIVE: HDL (high-density lipoprotein) infusion reduces atherosclerosis in animal models and is being evaluated as a treatment in humans. Studies have shown either anti- or proinflammatory effects of HDL in macrophages, and there is no consensus on the underlying mechanisms. Here, we interrogate the effects of HDL on inflammatory gene expression in macrophages. Approach and Results: We cultured bone marrow-derived macrophages, treated them with reconstituted HDL or HDL isolated from APOA1Tg;Ldlr-/- mice, and challenged them with lipopolysaccharide. Transcriptional profiling showed that HDL exerts a broad anti-inflammatory effect on lipopolysaccharide-induced genes and proinflammatory effect in a subset of genes enriched for chemokines. Cholesterol removal by POPC (1-palmitoyl-2-oleoyl-glycero-3-phosphocholine) liposomes or ß-methylcyclodextrin mimicked both pro- and anti-inflammatory effects of HDL, whereas cholesterol loading by POPC/cholesterol-liposomes or acetylated LDL (low-density lipoprotein) before HDL attenuated these effects, indicating that these responses are mediated by cholesterol efflux. While early anti-inflammatory effects reflect reduced TLR (Toll-like receptor) 4 levels, late anti-inflammatory effects are due to reduced IFN (interferon) receptor signaling. Proinflammatory effects occur late and represent a modified endoplasmic reticulum stress response, mediated by IRE1a (inositol-requiring enzyme 1a)/ASK1 (apoptosis signal-regulating kinase 1)/p38 MAPK (p38 mitogen-activated protein kinase) signaling, that occurs under conditions of extreme cholesterol depletion. To investigate the effects of HDL on inflammatory gene expression in myeloid cells in atherosclerotic lesions, we injected reconstituted HDL into Apoe-/- or Ldlr-/- mice fed a Western-type diet. Reconstituted HDL infusions produced anti-inflammatory effects in lesion macrophages without any evidence of proinflammatory effects. CONCLUSIONS: Reconstituted HDL infusions in hypercholesterolemic atherosclerotic mice produced anti-inflammatory effects in lesion macrophages suggesting a beneficial therapeutic effect of HDL in vivo.

Mutations in fast skeletal troponin I, troponin T, and beta-tropomyosin that cause distal arthrogryposis all increase contractile function.

Distal arthrogryposes (DAs) are a group of disorders characterized by congenital contractures of distal limbs without overt neurological or muscle disease. Unexpectedly, mutations in genes encoding the fast skeletal muscle regulatory proteins troponin T (TnT), troponin I (TnI), and beta-tropomyosin (beta-TM) have been shown to cause autosomal dominant DA. We tested how these mutations affect contractile function by comparing wild-type (WT) and mutant proteins in actomyosin ATPase assays and in troponin-replaced rabbit psoas fibers. We have analyzed all four reported mutants: Arg63His TnT, Arg91Gly beta-TM, Arg174Gln TnI, and a TnI truncation mutant (Arg156ter). Thin filaments, reconstituted using actin and WT troponin and beta-TM, activated myosin subfragment-1 ATPase in a calcium-dependent, cooperative manner. Thin filaments containing either a troponin or beta-TM DA mutant produced significantly enhanced ATPase rates at all calcium concentrations without alternating calcium-sensitivity or cooperativity. In troponin-exchanged skinned fibers, each mutant caused a significant increase in Ca2+ sensitivity, and Arg156ter TnI generated significantly higher maximum force. Arg91Gly beta-TM was found to have a lower actin affinity than WT and form a less stable coiled coil. We propose the mutations cause increased contractility of developing fast-twitch skeletal muscles, thus causing muscle contractures and the development of the observed limb deformities.