Diagnosis and Risk Assessment of Lower Extremity Peripheral Arterial Disease

Risk of undiagnosed coronary artery disease associated with infrapopliteal artery occlusion from a multicenter study

Peripheral artery disease (PAD) is associated with high cardiovascular mortality. Which part of PAD with lower extremities is related to coronary artery disease (CAD) remains unknown. We hypothesized that PAD including infrapopliteal artery (IPA) occlusion was associated with CAD. A total of 260 patients who have no history of CAD or the anginal symptom, complain of the claudication or critical limb ischemia and underwent peripheral angiography were retrospectively analyzed. IPA occlusion was diagnosed with peripheral angiography, and CAD was diagnosed with the coronary angiography. A multivariate logistic regression analysis was performed to determine the predictors of silent CAD. Among them, a total of 146 patients (56.2%) had IPA occlusion. Baseline characteristics were significantly different between two groups as to the proportions of age, male, dyslipidemia (with vs. without IPA occlusion; 72.4 ± 10.8 vs. 69.1 ± 10.2; 62.3% vs. 75.4%; 38.6% vs. 52.6%, respectively, all comparisons P < 0.05). Notably, the prevalence of CAD was significantly higher in patients with IPA occlusion (50.7% vs. 34.2%, P = 0.008). On a multivariate analysis, IPA occlusion was an independent predictor for the presence of silent CAD (OR, 1.94; CI, 1.09-3.44, P = 0.024), but aortoiliac artery occlusion (OR, 1.16; CI, 0.53-2.56, P = 0.71) and femoropopliteal artery occlusion (OR, 1.02; CI, 0.57-1.83, P = 0.96) were not. IPA occlusion was associated with silent CAD. Vascular surgeons, interventional radiologists, as well as interventional cardiologists should recognize IPA occlusion as a risk factor of silent CAD.

Circulating Small Non-coding RNAs as Biomarkers for Recovery After Exhaustive or Repetitive Exercise

Circulating microRNAs have proven to be reliable biomarkers, due to their high stability, both in vivo in the circulation, and ex vivo during sample preparation and storage. Small nucleolar RNAs (snoRNAs) are a different type of small non-coding RNAs that can also be reliably measured in plasma, but have only been studied sporadically. In this study, we aimed to identify RNA-biomarkers that can distinguish between different exercise regimes and that entail clues about muscle repair and recovery after prolonged exhaustive endurance exercise. We compared plasma microRNA profiles between two cohorts of elite cyclists, subjected to two different types of exercise regimes, as well as a cohort of patients with peripheral artery disease (PAD) that were scheduled to undergo lower limb amputation, due to critical limb ischemia. In elite athletes, muscle tissue recovers quickly even after exhaustive exercise, whereas in PAD patients, recovery is completely impaired. Furthermore, we measured levels of a specific group of snoRNAs in the plasma of both elite cyclists and PAD patients. Using a multiplex qPCR screening, we detected a total of 179 microRNAs overall, of which, on average, 161 microRNAs were detected per sample. However, only 30 microRNAs were consistently expressed in all samples. Of these, two microRNAs, miR-29a-3p and miR193a-5p, that responded differently two different types of exercise, namely exhaustive exercise and non-exhaustive endurance exercise. Using individual rt/qPCR, we also identified a snoRNA, SNORD114.1, which was significantly upregulated in plasma in response to endurance exercise. Furthermore, two microRNAs, miR-29a-3p and miR-495-3p, were significantly differentially expressed in athletes compared to PAD patients, but only following exercise. We suggest that these two microRNAs could function as markers of impaired muscle repair and recovery. In conclusion, microRNAs miR-29a-3p and miR-193a-5p may help us distinguish between repeated exhaustive and non-exhaustive endurance exercise. MicroRNA miR-29a-3p, as well as miR-495-3p, may further mark impaired muscle recovery in patients with severe critical limb ischemia. Furthermore, we showed for the first time that a circulating snoRNA, SNORD114.1, is regulated in response to exercise and may be used as biomarker.

Intraindividual Variability and Association of Human Collateral Supply to Different Arterial Regions

The intraindividual variability and association of human collateral functional supply to different arterial regions is unknown. The primary study end point was collateral flow index (CFI) as obtained in the coronary artery (CA), renal artery (RA), left superficial femoral artery (SFA), and left subclavian artery (SCA) of the same individual. CFI is the ratio between simultaneously recorded mean arterial occlusive pressure divided by mean aortic pressure both subtracted by mean central venous pressure. In 100 patients admitted for diagnostic coronary angiography, CFI was assessed in 3 arterial regions (CA, RA, and SFA), 13 patients underwent CFI measurements in all 4 territories. By quantitative coronary angiography, 82 patients had a stenosis <50% in diameter in the CA who underwent CFI measurement. CFI in the CA, RA, left SFA, and left SCA region amounted to 0.110 ± 0.093, 0.119 ± 0.082, 0.512 ± 0.147, and 0.563 ± 0.155, respectively (p <0.0001). There was a direct and linear correlation between CA and SFA CFI: CFI_SFA = 0.47 + 0.47CFI_CA (r(2) = 0.05; p = 0.0259). In patients with CFI values in all 4 arterial regions, an inverse linear relation between left SFA and left SCA CFI was observed: CFI_SCA = 0.91-0.67CFI_SFA (r(2) = 0.36; p = 0.0305). In conclusion, intraindividual, preexistent collateral function is widely varying between different arterial supply areas. On average, collateral flow ranges from approximately 12% in comparison to flow during arterial patency in the coronary and renal circulation to over 50% in the left SFA and left SCA, that is, circle of Willi's territory. CA and SFA CFIs are directly related to each other.

Methods of symptom evaluation and their impact on peripheral artery disease (PAD) symptom prevalence: a review

Peripheral artery disease (PAD) is a common progressive atherosclerotic occlusive disease that causes insufficient blood flow to the lower extremities. The symptom that health care professionals most often associate with PAD is claudication. However, patient reporting of claudication is highly variable. A structured literature review was conducted to evaluate how PAD symptoms are identified, defined, and categorized. This review focuses on the development and performance characteristics of PAD symptom questionnaires and the identification of a spectrum of leg symptoms beyond classic claudication. Additionally, potential confounders of PAD symptom reporting and strategies for a more comprehensive assessment of PAD symptoms are discussed. Overall, there is a lack of consistency in the utilization of PAD claudication questionnaires which impacts PAD symptom reporting and categorization. Based on this review, atypical symptoms are commonly reported, but poorly understood. Additional research is needed to gain a better understanding of the presentation of atypical symptoms, as well as the role of age, gender, race, and comorbid conditions on the symptom experience of patients with PAD.

Genetic architecture underlying variation in extent and remodeling of the collateral circulation

RATIONALE

Collaterals are arteriole-to-arteriole anastomoses that connect adjacent arterial trees. They lessen ischemic tissue injury by serving as endogenous bypass vessels when the trunk of 1 tree becomes narrowed by vascular disease. The number and diameter ("extent") of native (preexisting) collaterals, plus their amount of lumen enlargement (growth/remodeling) in occlusive disease, show remarkably wide variation among inbred mouse strains (eg, C57BL/6 and BALB/c), resulting in large differences in tissue injury in models of occlusive disease. Evidence suggests similar large differences exist among healthy humans.

OBJECTIVE

To identify candidate loci responsible for genetic-dependent collateral variation.

METHODS AND RESULTS

Cerebral collateral number and diameter were determined in 221 C57BL/6xBALB/c F2 progeny, followed by linkage analysis to identify quantitative trait loci (QTL) for collateral number and diameter. Four QTL were obtained for collateral number, including epistasis between 2 loci. A QTL that was identical to the strongest QTL for collateral number on chromosome 7 (logarithm of the odds [LOD]=29, effect size=37%) was also mapped for collateral diameter (LOD=17, effect size=30%). Chromosome substitution strain analysis confirmed this locus. We also obtained a unique QTL on chromosome 11 for collateral remodeling after middle cerebral artery occlusion. Association mapping within the chromosome 7 QTL interval using collateral traits measured for 15 inbred strains delineated 172-kbp (P=0.00002) and 290-kbp (P=0.0004) regions on chromosome 7 containing 2 and 7 candidate genes, respectively.

CONCLUSIONS

We conclude that collateral extent and remodeling are unique, highly heritable complex traits, with 1 QTL predominantly affecting native collateral number and diameter.

Prevalência da doença arterial obstrutiva periférica em doentes com insuficiência renal crônica

Contexto: A doença arterial obstrutiva periférica tem sido reconhecida como um sensível marcador de aterosclerose sistêmica e preditora de eventos cardiovasculares. Apesar da alta prevalência da doença cardiovascular, há poucos estudos sobre a doença arterial obstrutiva periférica em pacientes com insuficiência renal crônica em tratamento hemodialítico. Objetivo: Determinar a prevalência de doença arterial obstrutiva periférica em pacientes com insuficiência renal crônica em uma clínica de referência para tratamento hemodialítico no estado de Sergipe. Métodos: Trata-se de um estudo transversal, realizado no período de junho a novembro de 2008, em uma clínica de referência para tratamento de pacientes com insuficiência renal crônica. Foram caracterizados como portadores de doença arterial obstrutiva periférica os pacientes que apresentavam índice tornozelo-braquial (ITB) ≤ 0,9. Resultados: De uma população de 239 pacientes com insuficiência renal crônica, foram avaliados 201. Destes, 28 (14%) apresentavam insuficiência arterial periférica com ITB ≤ 0,9. A idade variou de 24 a 82 anos, com média de 52 anos. A hipertensão e a dislipidemia foram os fatores de risco mais frequentes. Dos pacientes com doença arterial obstrutiva periférica, 89% eram dislipidêmicos, 71% hipertensos e 29% tinham coronariopatias. Conclusão: A prevalência de doença arterial obstrutiva periférica em doentes com insuficiência renal crônica foi de 14%.

[Chronic critical ischemia of the lower leg: pretherapeutic imaging and methods for revascularization]

Each year 1-2% of patients with peripheral arterial occlusive disease (pAOD) develop critical limb ischemia (CLI), characterized by rest pain and peripheral ulcer or gangrene. This aggravation of the disease is accompanied by an increase of the 1-year mortality rate up to 25% and a similarly increased frequency of major amputation. We can choose between conservative, endovascular, and surgical procedures for an adequate therapy of the underlying vascular stenoses or occlusions. Yet, clear therapeutic recommendations only exist for suprapopliteal lesions. However, in a number of cases, especially in diabetics, target lesions have an infrapopliteal location. Since endovascular procedures have undergone significant improvement in the last few years, the following review discusses methods for infrapopliteal revascularization taking into consideration the newest publications on this topic.