Underuse of Cardiovascular Medications in Individuals With Known Lower Extremity Peripheral Artery Disease: HCHS/SOL

Background

Underuse of cardiovascular medications for secondary prevention among individuals with peripheral artery disease (PAD) has been reported. Little is known about PAD treatment status in the Hispanic/Latino population in the United States, who may have limited access to health care and who have worse clinical outcomes than non‐Hispanic individuals.

Methods and Results

We studied the use of cardiovascular therapies in 1244 Hispanic/Latino individuals recruited from 4 sites in the United States, including 826 individuals who reported diagnosis of PAD by physician and 418 individuals with coronary artery disease alone, in the Hispanic Community Health Study/Study of Latinos. We compared the prevalence of using antiplatelet therapy, lipid‐lowering therapy and antihypertensive therapy by PAD and coronary artery disease status. Among those with PAD, we studied factors associated with taking cardiovascular medications, including demographic and socioeconomic factors, acculturation, access to health care and comorbidities, using multivariable regression models. The overall prevalence for individuals with PAD taking antiplatelet therapy, lipid‐lowering therapy and, among hypertensive individuals, antihypertensive therapy was 31%, 26% and 57%, respectively. Individuals of Mexican background had the lowest use for all classes of cardiovascular medications. Older age, number of doctor visits and existing hypertension and diabetes mellitus were significantly associated with taking cardiovascular therapies in adjusted models. Compared with those with PAD alone, individuals with PAD and concurrent coronary artery disease were 1.52 (95% CI, 1.20–1.93) and 1.74 (1.30–2.32) times more likely to use antiplatelet agents and statins according to multivariable analysis. No significant difference of antihypertensive medication use was found among PAD patients with or without coronary artery disease.

Conclusions

Hispanic/Latino individuals with known PAD underuse cardiovascular medications recommended in clinical guidelines. More efforts should be directed to improve treatment in this important group.

Delineating effect of corn microRNAs and matrix, ingested as whole food, on gut microbiota in a rodent model

Dietary microRNAs (miRNAs) are thought to regulate a wide range of biological processes, including the gut microbiota. However, it is difficult to separate specific effect(s) of miRNA from that of the food matrix. This study aims to elucidate the specific effect(s) of dietary corn miRNAs, ingested as a whole food, on the gut microbiota. We developed an autoclave procedure to remove 98% of miRNA from corn. A mouse feeding study was conducted comparing autoclaved corn to nonautoclaved corn and purified corn miRNA. Compared to nonspecific nucleotides and corn devoid of miRNAs, feeding purified corn miRNAs or corn to C57BL/6 mice via gavage or diet supplementation for two weeks lead to a decrease in total bacteria in the cecum. The effect appeared to be due to changes in Firmicutes. Additionally, corn matrix minus miRNA and processing also affected gut bacteria. In silico analysis identified corn miRNAs that aligned to Firmicutes genome sequences lending further support to the interaction between corn miRNAs and this bacterium. These data support interactions between plant food miRNA, as well as matrix, and the gut microbiota exist but complex. However, it provides additional support for mechanism by which bioactive dietary components interact with the gut microbiota.

Gut Microbiota-Dependent Trimethylamine N-oxide and Cardiovascular Outcomes in Patients With Prior Myocardial Infarction: A Nested Case Control Study From the PEGASUS-TIMI 54 Trial

Background Trimethylamine N-oxide (TMAO) may have prothrombotic properties. We examined the association of TMAO quartiles with major adverse cardiovascular events (MACE) and the effect of TMAO on the efficacy of ticagrelor. Methods and Results PEGASUS-TIMI 54 (Prevention of Cardiovascular Events in Patients With Prior Heart Attack Using Ticagrelor Compared to Placebo on a Background of Aspirin - Thrombolysis in Myocardial Infarction 54) randomized patients with prior myocardial infarction to ticagrelor or placebo (median follow-up 33 months). Baseline plasma concentrations of TMAO were measured in a nested case-control study of 597 cases with cardiovascular death, myocardial infarction, or stroke (MACE) and 1206 controls matched for age, sex, and estimated glomerular filtration rate [eGFR]. Odds ratios (OR) were used for the association between TMAO quartiles and MACE, adjusting for baseline clinical characteristics (age, sex, eGFR, region, body mass index, hypertension, hypercholesterolemia, diabetes mellitus, smoking, peripheral artery disease, index event, aspirin dosage and treatment arm), and cardiovascular biomarkers (hs-TnT [high-sensitivity troponin T], hs-CRP [high-sensitivity C-reactive protein], NT-proBNP [N-terminal-pro-B-type natriuretic peptide]). Higher TMAO quartiles were associated with risk of MACE (OR for quartile 4 versus quartile 1, 1.43, 95% CI, 1.06-1.93, P trend=0.015). The association was driven by cardiovascular death (OR 2.25, 95% CI, 1.28-3.96, P trend=0.003) and stroke (OR 2.68, 95% CI, 1.39-5.17, P trend<0.001). After adjustment for clinical factors, the association persisted for cardiovascular death (ORadj 1.89, 95% CI, 1.03-3.45, P trend=0.027) and stroke (ORadj 2.01, 95% CI, 1.01-4.01, P trend=0.022), but was slightly attenuated after adjustment for cardiovascular biomarkers (cardiovascular death: ORadj 1.74, 95% CI, 0.88-3.45, P trend=0.079; and stroke: ORadj 1.82, 95% CI, 0.88-3.78, P trend=0.056). The reduction in MACE with ticagrelor was consistent across TMAO quartiles (P interaction=0.92). Conclusions Among patients with prior myocardial infarction, higher TMAO levels were associated with cardiovascular death and stroke but not with recurrent myocardial infarction. The efficacy of ticagrelor was consistent regardless of TMAO levels. Registration URL: https://www.clini​caltr​ials.gov; Unique identifiers: PEGASUS-TIMI 54, NCT01225562.

Associations of Peripheral Artery Disease With Calf Skeletal Muscle Mitochondrial DNA Heteroplasmy

Background Patients with peripheral artery disease (PAD) undergo frequent episodes of ischemia-reperfusion in lower extremity muscles that may negatively affect mitochondrial health and are associated with impaired mobility. We hypothesized that skeletal muscle from PAD patients will show high mitochondrial DNA heteroplasmy, especially in regions more susceptible to oxidative damage, such as the displacement loop, and that the degree of heteroplasmy will be correlated with the severity of ischemia and mobility impairment. Methods and Results Mitochondrial mutations and deletions and their relative abundance were identified by targeted mitochondrial DNA sequencing in biopsy specimens of gastrocnemius muscle from 33 PAD (ankle brachial index <0.9) and 9 non-PAD (ankle brachial index >0.9) subjects aged ≥60 years. The probability of heteroplasmy per DNA base was significantly higher for PAD subjects than non-PAD within each region. In adjusted models, PAD was associated with higher heteroplasmy than non-PAD (P=0.003), but the association was limited to microheteroplasmy, that is heteroplasmy found in 1% to 5% of all mitochondrial genomes (P=0.004). Heteroplasmy in the displacement loop and coding regions were significantly higher for PAD than non-PAD subjects after adjustment for age, sex, race, and diabetes mellitus (P=0.037 and 0.004, respectively). Low mitochondrial damage, defined by both low mitochondrial DNA copy number and low microheteroplasmy, was associated with better walking performance. Conclusions People with PAD have higher "low frequency" heteroplasmy in gastrocnemius muscle compared with people without PAD. Among people with PAD, those who had evidence of least mitochondrial damage, had better walking performance than those with more mitochondrial damage. Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02246660.