Liedl, David

Introduction: Patients with concomitant peripheral artery disease (PAD) and heart failure (HF) are known to have increased morbidity and mortality. Though they share common risk factors, the utility of HF screening in patients with PAD remains controversial and without international consensus. We sought to clarify whether PAD is an independent risk factor for HF. Methods: We performed a retrospective analysis of adult patients without a history of heart failure who underwent ankle brachial index (ABI) measurement for any indication between 1995-2020. Patients were then stratified by ABI: PAD with low ABI (<1.10), healthy (ABI= 1.10-1.39), and PAD with elevated ABI (>1.39). The associations between PAD and incident diagnosis of heart failure, systolic dysfunction (HF with reduced ejection fraction, HFrEF), and diastolic dysfunction (HF with preserved ejection fraction, HFpEF) were assessed. All patient and outcomes variables were obtained using the institutional electronic health record. Multivariable Cox proportional regression was used to calculate hazard ratios (HR) with 95% confidence intervals (CI) after adjusting for age, sex, hypertension, diabetes, and active tobacco use. Results: The cohort included 36,816 patients (median follow-up 4.21 years), of whom 2,116 (5.7%) were diagnosed with HF. Among HF patients, 1,110 (3.0%) had HFrEF and 1,006 (2.7%) had HFpEF. Both low and elevated ABI groups were associated with an increased risk of HF, both HFrEF, and HFpEF. After multivariable analysis, PAD with elevated ABI was associated with higher overall HF risk (HR, 2.36 [95% CI, 2.03, 2.73]) than low ABI (HR, 1.56 [95% CI, 1.40, 1.74]) when compared to normal ABI. Similarly, PAD with elevated ABI was associated with greater risk of HFrEF (HR, 2.37 [95% CI, 1.93, 2.92]) and HFpEF (HR, 1.82 [95% CI, 1.48, 2.25]) than PAD with low ABI (HFrEF: HR 1.77 [95% CI, 1.52, 2.07], HFpEF: HR 1.31 [95% CI, 1.12, 1.52]). Conclusions: PAD, especially with elevated ABI, is an independent risk factor for heart failure even after adjusting for common HF risk factors. Our findings support HF screening in PAD patients, but longitudinal data on HF morbidity and mortality is necessary to evaluate the value of this practice.

Introduction: Peripheral arterial disease (PAD) increases cardiovascular (CV) morbidity and mortality, but remains underdiagnosed and undertreated. Several trials support low-dose rivaroxaban in PAD treatment, although this has yet to be widely adopted in clinical practice. The effect of warfarin and direct oral anticoagulants (DOACs) on comprehensive PAD outcomes warrants further study. Hypothesis: Anticoagulant therapy, particularly DOACs, improves CV outcomes in PAD. Methods: We conducted a retrospective study of patients who underwent ankle-brachial index testing (ABI) from 1996 – 2020 at Mayo Clinic. We included patients with PAD defined by abnormal ABI (<1.0 or >/=1.4). Prolonged (>6 months) DOAC or warfarin use was compared to no anticoagulant therapy. Multivariable (MV) regression, controlling for baseline CV risk factors, was used. Results: 21,891 patients had abnormal ABI readings; 3,093 were on warfarin and 267 were on DOAC for any indication. Anticoagulation improved mortality, with DOACs superior to warfarin. DOACs improved critical limb ischemia (CLI)/amputation in univariate analysis, although this was not significant in MV. Patients with poorly compressible vessels (ABI >/=1.4) had increased limb outcomes compared to reduced ABI (<1.0). Ischemic stroke and myocardial infarction occurred more frequently in those on anticoagulation, but the risk was less for DOACs vs. warfarin. Notably, both anticoagulant groups had greater baseline comorbidity than the non-anticoagulant group; the DOAC and warfarin groups were similar. Major bleeding (6.7%) was increased in both anticoagulant groups, but less so with DOACs and this was similar to the bleeding risk seen with aspirin (HR 1.20). Conclusion: Anticoagulant therapy improved mortality in a large cohort of PAD patients. The risk of limb events appears improved in those on DOACs. DOACs showed improved risk profiles compared to warfarin regarding CV and bleeding outcomes.

Abstract Context Peripheral artery disease (PAD) is highly prevalent in the general population, affecting up to 25% of patients 55 years of age or older. There is a known association with acute ischemic stroke, but limited large cohort studies exist pertaining to the relationship between PAD severity and incident ischemic stroke. Objectives To evaluate the risk of incident ischemic stroke and mortality along the spectrum of low and elevated ankle brachial index (ABI) measurement. Methods We performed a retrospective extraction of ABI data of all adult patients who underwent lower extremity physiology study for any indication from January 1, 1996 to June 30, 2018 in the Mayo Clinic health system. PAD was categorized into severe, moderate, mild, and borderline based on ABI measurements and poorly compressible arteries (PCA). These were compared with normal ABI measurements. Associations of PAD/PCA with new ischemic stroke events and all cause mortality were analyzed. Hazard ratios (HR) were calculated using multivariable Cox proportional regression with 95% confidence intervals. Results A total of 39,834 unique patients were included with a median follow up duration of 4.59 years. All abnormal ABI groups, except borderline PAD, were associated with increased risk of incident ischemic stroke after multivariate regression compared to normal ABI. A severity-dependent association was observed between PAD and ischemic stroke with moderate (HR, 1.22 [95% CI, 1.10–1.35]) and severe (HR, 1.19 [95% CI, 1.02–1.40]) categories conferring similar risk in comparison to normal ABI. Patients with PCA carried the greatest ischemic stroke risk (HR, 1.30 [95% CI, 1.15–1.46]). Similarly, abnormal ABI groups were associated with a significant risk for all cause mortality in a severity-dependent manner, with severe PAD conferring the greatest risk (HR, 3.07 [95% CI, 2.88–3.27]). Conclusions This study adds to the growing body of evidence that both PAD and PCA are independent risk factors for incident ischemic stroke and all cause mortality. The association of PAD severity and PCA with risk of ischemic stroke may help clinicians with risk stratification and determining treatment intensity.

Abstract The calf muscle pump is a major determinate of venous return in the legs but has not been studied as a risk factor for venous thromboembolism (VTE). A population-based cohort study of Olmsted County, Minnesota residents was performed using calf pump function (CPF) measurements from venous plethysmography studies from 1998 to 2015. Patients with a history of VTE were excluded. Nursing validated VTE outcomes from the Rochester Epidemiology Project were identified after the index study date, and patients with reduced CPF (rCPF) were compared with patients with normal CPF. A total of 1532 patients with recorded CPF (28% air and 72% strain gauge plethysmography) were included; 591 (38.5%) had normal CPF, 353 (23.0%) had unilateral rCPF, and 588 (38.3%) had bilateral rCPF. Any VTE occurred in 87 patients (5.7%) after a median follow-up of 11.7 years (range, 0-22.0 years). Comparing patients with bilateral reduced to bilateral normal CPF, the unadjusted hazard ratio (HR) for incident VTE was 2.0 (95% confidence interval [CI], 1.2-3.4) and after adjusting for age, BMI, and Charlson Comorbidity Index, the HR was 1.68 (95% CI, 0.98-2.89). The adjusted HR for ipsilateral deep vein thrombosis was evaluated in 3064 legs comparing legs with reduced to normal CPF and was 1.71 (95% CI, 1.03-2.84). Mortality was significantly higher in both the bilateral (P &lt; .001) and unilateral (P &lt; .001) rCPF groups compared with normal CPF. Our results demonstrate that CPF is a risk factor for VTE in an otherwise low-risk ambulatory population and might be a useful component in risk stratification models.

Background: Venous return from the lower extremities is pumped upwards to the right side of the heart in a process that is facilitated by one-way valves and the venous muscle pump, of which the calf muscle pump is a major contributor1-3. Venous plethysmography can quantitatively assess calf pump function (CPF). The association between the CPF and venous thromboembolism (VTE) has not been investigated. Methods: Venous plethysmography (VP) data (strain gauge or air plethysmography) from the Mayo Clinic Vascular Lab database (1998-2015) of CPF (bilaterally reduced, unilaterally reduced, and bilateral normal) were examined in Olmsted County Residents. The Rochester Epidemiology Project (REP) captures the population of Olmsted County and contains demographic information, medical diagnoses, hospital admissions, and surgical procedures as well as validated VTE events and death. Patients with signs of obstructed outflow in either extremity on the venous plethysmography (a possible sign of acute or chronic deep vein thrombosis) study were excluded. Patients with a history of VTE diagnosed before the physiologic study were also excluded. If more than one measurement of calf muscle pump function was performed, only the first measurement was used. The primary outcome was a composite of any VTE, including proximal and distal deep vein thrombosis (DVT) and pulmonary embolism (PE). Results: 1703 Olmsted County residents had venous plethysmography studies performed. MN research authorization was denied in 64 patients and 107 were excluded for any documented VTE preceding index VP study. 1532 patients with recorded CPF (28% air and 72% strain gauge plethysmography) were studied: 591 (38.5%) had normal CPF, 353 (23.0%) had unilateral reduced CPF (rCPF), and 588 (38.3%) had bilateral rCPF. The mean age was 64.4 (SD 18.4), 68.9% were female, and the mean BMI was 29.5 (SD 6.4). Any VTE occurred in 87 patients (5.7%) after a mean follow up of 10.9 years (range 0-22.0 years). Isolated lower extremity DVT (excluding concurrent PE) occurred in 49 patients and PE+/-DVT occurred in 38 patients. Death occurred in 352 patients (23%). Bilateral rCPF compared to bilateral normal CPF was associated with VTE (p=0.007), DVT only (p=0.02) and death (p&lt;0.001) but not PE+/-DVT (p=0.13). Unilateral rCPF compared to bilateral normal CPF was not associated with VTE, but was associated with death (p&lt;0.001). Kaplan-Meier curves for VTE and death are shown in Figure 1. The hazard ratio for bilateral rCPF compared to bilateral normal CPF for VTE was 2.0 (95% CI 1.2-3.4) and for DVT only was 2.2 (95% CI 1.1-4.2). A sensitivity analysis for the main outcome of VTE did not show significant interaction based on the type of plethysmography (strain vs. air), by age stratified at 65 years, sex, or BMI stratified at 30 (p&gt;0.1 for each comparison). Conclusion: In this population-based study of Olmsted County residents with no prior VTE, rCPF function as measured by venous plethysmography is associated with increased risk for VTE, particularly lower extremity proximal DVT. More research is required to understand what additional measures of venous physiology influence these findings and whether CPF could be used in VTE risk stratification. Disclosures No relevant conflicts of interest to declare.

Abstract Introduction Antiplatelet therapy is the cornerstone of treatment for many atherosclerotic vascular pathologies including peripheral arterial disease (PAD). Patients with PAD often have comorbid conditions that require complex antithrombotic therapy, i.e. combined antiplatelet and anticoagulation. Methods All adult patients undergoing ankle brachial index (ABI) measurements were included in the study. ABI values between 1.00 and 1.40 were considered normal, and values below 1.00 or above 1.40 were considered PAD. Demographic, comorbidity and outcome data were obtained using diagnostic codes from the electronic health record. Three medication classes were analyzed: aspirin, non-aspirin oral antiplatelets (e.g. P2Y12 inhibitors) and oral anticoagulants (warfarin and the direct oral anticoagulants). Medication use was determined for patients who had been on a medication for at least one year. Cox proportional hazard analysis for the time to first bleeding event was analyzed. Bleeding was defined as any bleeding requiring medical evaluation (including clinically-relevant non-major bleeding and major bleeding). Results In all, 40,144 patients were included in the analysis (mean age 66±15, 43% female). Patients with PAD were more likely to be on double therapy (one antiplatelet with anticoagulation) (28% vs 19%) and triple therapy (dual antiplatelet with anticoagulation) (10% vs 4%). Unadjusted hazard ratios for bleeding risk showed increased risk of bleeding for patients with PAD (1.18, 95% confidence interval [CI]: 1.08–1.29), though the association is no longer present after adjustment for antithrombotic therapy. Adjusting for age, sex and PAD class, compared to no antithrombotic therapy, there was increased risk of bleeding for monotherapy (1.91, 95% CI: 1.61–2.26), double therapy (3.40, 95% CI: 2.89–4.00) and triple therapy (5.00, 95% CI: 4.21–5.96). Among medications, aspirin and anticoagulant use was independently associated with the greatest increase in risk of bleeding. Conclusion Patients in PAD are at increased risk of bleeding secondary to antithrombotic therapy. Complex antithrombotic therapy with double or triple therapy confer additional bleeding risk, particularly regimens containing aspirin and oral anticoagulants. Funding Acknowledgement Type of funding source: None

Abstract Introduction Given the potential side effects and the lack of data on its efficacy, the role of statins in the very elderly (age 75+) with peripheral arterial disease (PAD) is uncertain. Previous studies have shown significant mortality benefit in very elderly patients with coronary artery disease, but the effect in PAD has not been evaluated. Methods Very elderly patients aged 75 to 80 with at least five years of follow-up who underwent ankle-brachial index (ABI) measurement were included. PAD was defined as either low ABI &lt;0.90 or high ABI &gt;1.40. Demographic, medication use, comorbidity and mortality data was obtained using the electronic medical record. Univariate and multivariate Cox proportional hazard analyses were performed. Results In total, 4,560 very elderly subjects with PAD were included in the analysis. The median age was 77 (interquartile range 76–79) and 39% were female. 3,462 (76%) had low ABI while 1098 (24%) had high ABI. Univariate analysis showed that patients on statins were more likely to be male, have diabetes, have coronary artery disease, and have hyperlipidemia. Overall, 1,355 (30%) patients died in the five-year period. Unadjusted all-cause mortality hazard ratios for patients with low or high ABI with statin use was 0.66 (95% confidence interval [CI]: 0.57–0.75) and 0.80 (95% CI: 0.66–0.97), respectively. After adjusting for age, sex, coronary artery disease and diabetes, statin use in low and high ABI was still associated with significant reductions in risk of all-cause mortality of 0.59 (95% CI: 0.51–0.67) and 0.66 (95% CI: 0.54–0.80), respectively. The survival curve for very elderly patients with PAD by statin use is shown in Figure 1. Conclusion Statin use in the very elderly was associated with lower risk of all-cause mortality in the five-year period after diagnosis of PAD. There appears to be a mortality benefit with statin use in the very elderly with PAD, though careful consideration of benefits and side effects should be individualized in this age group. Figure 1 Funding Acknowledgement Type of funding source: None

Calf muscle pump (CMP) promotes venous return from the lower extremity and contributes to preload and cardiac output. Impaired CMP function may reflect a measure of frailty or cumulative disease burden or may impede cardiac function. The study objective was to test the hypothesis that impaired CMP negatively impacts survival. Consecutive adult patients who underwent venous strain gauge plethysmography at the Mayo Clinic Gonda Vascular Laboratory (January 1, 1998 – December 31, 2011) were assessed for overall survival. Patients with venous incompetence, venous obstruction or unilateral calf pump dysfunction were excluded. Risk of mortality was assessed with Cox proportional hazard ratios and after adjusting for Charlson Comorbidity Index variables. Over the study period, 2728 patients were included in the analysis. Compared to patients with normal CMP, those with impaired CMP were older ( p < 0.001), predominantly female ( p = 0.01) and had higher mean Charlson scores ( p < 0.001). Patients with impaired CMP had a higher mortality rate at 5 (8.9% vs 2.4%), 10 (17.5% vs 5.9%), and 15 years (22.8% vs 8.3%) compared to those with normal CMP ( p < 0.001 for each comparison). Of patients with heart failure, those with impaired CMP had worse survival at each 5-year increment compared to those with normal CMP ( p < 0.05 at each increment). In conclusion, impaired CMP appears to be an independent predictor of poor outcomes after adjusting for variables within the Charlson Comorbidity Index. The association between impaired CMP, heart failure, and mortality may represent a negative impact on circulatory function or a surrogate measure of frailty.

Background Ankle‐brachial indexes ( ABI ) are a noninvasive diagnostic tool for peripheral arterial disease and a marker of increased cardiovascular risk. ABI is calculated using the highest systolic blood pressure of the 4 ankle arteries (bilateral dorsalis pedis and posterior tibial). Accordingly, patients may be assigned a normal ABI when the result would be abnormal if calculated using one of the other blood pressure readings. Cardiovascular outcomes for patients with discordant ABI s are undescribed. Methods and Results We performed a retrospective study of patients who underwent ABI measurement for any indication between January 1996 and June 2018. Those with normal ABI s (1.00–1.39) were included. We compared patients with all 4 normal ABI s (calculated using all 4 ankle arteries; n=15 577, median age 64.0 years, 54.4% men) to those with discordant ABI s (at least 1 abnormal ABI ≤0.99; n=2095, median age 66.0 years, 47.8% men). The outcomes assessed were ischemic stroke, myocardial infarction, and all‐cause mortality. Compared with patients with concordant normal ABI s, patients with discordant ABI s were older; women; smoked; and had chronic kidney disease, coronary artery disease, diabetes mellitus, chronic obstructive pulmonary disease, hypertension, or prior stroke. Patients with discordant ABI s had a greater risk of myocardial infarction (hazard ratio [HR], 1.31; 95% CI, 1.10–1.56), ischemic stroke ( HR, 1.53; 95% CI, 1.37–1.72), and all‐cause mortality ( HR, 1.27; 95% CI, 1.16–1.39), including after adjustment for baseline comorbidities. Conclusions Discordant ABI results were associated with an increased risk of myocardial infarction, stroke, and all‐cause mortality in the studied population. Clinicians should examine ABI calculations using all 4 ankle arteries to better characterize a patient's cardiovascular risk.

Abstract Background Peripheral arterial disease is a marker of aggressive atherosclerosis. The ankle brachial index (ABI) is a simple and non-invasive tool to diagnose peripheral arterial disease (PAD). Patients with PAD are at increased risk for ischemic strokes and other cardiovascular diseases. Purpose To evaluate the association of abnormal ABI and poorly compressible vessels with ischemic stroke in a large patient cohort. Methods We analyzed lower extremity vascular studies of all patients with ABI measurements at a tertiary care hospital between January 1996 and August 2018. PAD is defined as ABI<1.0, and poorly or non-compressible (PC/NC) arteries as ABI>1.4 while ABI between 1.0–1.4 is normal. Association of these ABIs with new ischemic stroke events post ABI measurement were analyzed after adjusting for high risk confounders such as atrial fibrillation. Hazard ratios (HR) were calculated using multivariable Cox proportional regression with 95% confidence intervals. Results In total, 38,016 unique patients (mean age 66.1±14.8 years, female 42.3%) were included. Abnormal ABI was found to be more prevalent among elderly male patients compared to patients with normal ABI. In contrast to non-PAD patients, both PAD and PC/NC patients as defined by ABI had a statistically significant risk of ischemic stroke, with PAD conferring the greatest risk compared to PC/NC vessels. The data is summarized in Table 1. Table 1 Unadjusted HR p-value Adjusted HR p-value PAD vs. No PAD 2.77 (2.62, 2.92) <0.001 2.10 (1.98, 2.22) <0.001 PC/NC vs. No PAD 2.11 (1.95, 2.28) <0.001 1.38 (1.26, 1.51) <0.001 PAD vs. PC/NC 1.37 (1.28, 1.46) <0.001 1.37 (1.28, 1.48) <0.001 Adjusted and unadjusted hazard ratios with p-values. HR adjusted for age, sex, atrial fibrillation, ischemic stroke, transient ischemic attack, chronic heart failure, diabetes mellitus, hyperlipidemia, hypertension, and coronary artery disease. PAD = Peripheral artery disease and PC/NC = poorly compressible/non-compressible. Conclusion This study adds to the growing body of evidence that PAD and poorly-compressible vessels are independently associated with an increased risk of ischemic stroke. Given the associated risk of cerebrovascular disease, clinicians should aggressively treat to minimize risk factors in those with abnormal ABIs.