Wennberg, Paul W.

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.

Abstract Introduction Lower extremity physiologic studies are an important non-invasive diagnostic tool in peripheral arterial disease (PAD). PAD and atrial fibrillation (AF) are associated with increased cardiovascular and all-cause mortality. Purpose To evaluate the association between PAD and new-onset AF and the risk of stroke. Methods We performed a study of all patients without AF undergoing ankle-brachial index (ABI) for any indication between January 1996 to June 2018. The ABI cut-off were as follows: abnormal ABI (0–0.99), normal ABI (1.00–1.39) and poor vessel compressibility (PC) (1.40+). Demographic, comorbidity, and outcome variables were extracted using the electronic medical record. Results Overall, 34,441 patients (mean age 66.8±14.3, 57.3% male, 88.2% white) were included in the study with a median follow-up of 7.2 years (interquartile range, 3.0–12.9 years). Multivariate Cox proportional hazard analysis showed increased risk of new-onset AF for male sex, older age, hypertension, coronary artery disease, cerebrovascular disease, chronic kidney disease stage III or greater, congestive heart failure, chronic obstructive pulmonary disease, and cancer (all p<0.0001). After adjustment, ABI results were significantly associated with new-onset AF, particularly poorly-compressible vessels (adjusted HR: 1.42 (1.30–1.55), p<0.0001) compared to abnormal ABI (adjusted HR: 1.12 (1.05–1.20), p=0.0012). Patients with atrial fibrillation were more likely to experience ischemic stroke (39.2% versus 16.1%, p<0.0001). Conclusion Abnormalities in ABI results, particularly poorly-compressible vessels, are independently associated with new-onset atrial fibrillation in a large ambulatory cohort. While the mechanism cannot be assessed, common inflammatory mechanisms and increased vascular stiffness may play an important role. Identification of AF in these at-risk patients may improve cardiovascular outcomes.

Abstract Background Based on previously published data, routine myocardial perfusion imaging in diabetics is not recommended. Selecting patients with diabetes and high risk cardiovascular features could be important to improve the yield of physiologic assessment of the coronary arteries disease and subsequently patient outcome. Purpose We posed the question whether nuclear stress testing has a better yield by selecting diabetic individuals with known vascular disease. Methods We analyzed records for 15,392 diabetics from 1996 to 2009 with and without vascular disease. Vascular disease is defined as carotid vascular disease, abdominal aortic aneurysm, or peripheral arterial disease. There was 2457 myocardial perfusion studies performed within 2 years of the vascular evaluation. We studied the results of these stress testing in each group and evaluated for the presence of myocardial ischemia. Multivariate Cox proportional regression was used to calculate hazard ratios (HR) with 95% confidence intervals after adjusting for age, gender. Results Of those who underwent myocardial perfusion studies 1819 were diabetic with vascular disease group A (mean age 67.8, 70.5% female) and 638 were diabetic without vascular disease group B (mean age 64.5 years, 67.1% female). There was at least one reversible defect suggest myocardial ischemia in 225 and 758 studies in group A and B respectively. Comparing outcome based on the presence of myocardial ischemia in group A without vascular disease, those with vascular disease did have an increased risk of myocardial infarction (adjusted HR: 1.630, 95% CI: 1.281–2.074) and death (adjusted HR: 1.646, 95% CI: 1.413–1.918). Conclusion Myocardial perfusion imaging is a reasonable test in patients with diabetes and vascular disease. The presence of myocardial ischemia is more common and is associated with worse cardiovascular outcome. Acknowledgement/Funding None

Background Automated individualized risk prediction tools linked to electronic health records ( EHR s) are not available for management of patients with peripheral arterial disease. The goal of this study was to create a prognostic tool for patients with peripheral arterial disease using data elements automatically extracted from an EHR to enable real‐time and individualized risk prediction at the point of care. Methods and Results A previously validated phenotyping algorithm was deployed to an EHR linked to the Rochester Epidemiology Project to identify peripheral arterial disease cases from Olmsted County, MN, for the years 1998 to 2011. The study cohort was composed of 1676 patients: 593 patients died over 5‐year follow‐up. The c‐statistic for survival in the overall data set was 0.76 (95% confidence interval [CI], 0.74–0.78), and the c‐statistic across 10 cross‐validation data sets was 0.75 (95% CI, 0.73–0.77). Stratification of cases demonstrated increasing mortality risk by subgroup (low: hazard ratio, 0.35 [95% CI, 0.21–0.58]; intermediate‐high: hazard ratio, 2.98 [95% CI, 2.37–3.74]; high: hazard ratio, 8.44 [95% CI, 6.66–10.70], all P <0.0001 versus the reference subgroup). An equation for risk calculation was derived from Cox model parameters and β estimates. Big data infrastructure enabled deployment of the real‐time risk calculator to the point of care via the EHR . Conclusions This study demonstrates that electronic tools can be deployed to EHR s to create automated real‐time risk calculators to predict survival of patients with peripheral arterial disease. Moreover, the prognostic model developed may be translated to patient care as an automated and individualized real‐time risk calculator deployed at the point of care.

Nitric oxide (NO) is an important endothelium-derived relaxing factor that functions via activation of soluble guanylyl cyclase and cGMP generation in vascular smooth muscle. Recently, studies have described the synthesis and secretion of C-type natriuretic peptide (CNP) from endothelial cells. This peptide also mediates relaxation via cGMP but through activation of particulate guanylyl cyclase. We tested the hypothesis that endothelium-dependent relaxations to acetylcholine or bradykinin in isolated canine coronary arteries involve both releases of NO and CNP. Rings of canine coronary arteries were incubated with either inhibitors of NO production ( NG-monomethyl-l-arginine,l-NMMA) or the natriuretic peptide receptor antagonist HS-142-1. CNP caused concentration-dependent relaxations of rings with and without endothelium. These relaxations were attenuated by HS-142-1. Relaxations to acetylcholine and bradykinin were attenuated byl-NMMA alone but not attenuated by HS-142-1 alone. Coinhibition withl-NMMA and HS-142-1 significantly inhibited acetylcholine- and bradykinin-induced relaxation to a magnitude greater than either inhibitor alone. In summary, a novel interaction between the NO and the natriuretic peptide system is demonstrated by increased attenuation of endothelium-dependent relaxations to acetylcholine and bradykinin when both NO synthase and natriuretic peptide receptors are inhibited. These investigations support the concept of release of multiple endothelium-derived factors in response to acetylcholine- and bradykinin-receptor stimulation in endothelial cells, which may include CNP, as well as NO.

Patients with end-stage renal disease undergoing kidney transplant often have diffuse atherosclerosis and high cardiovascular morbidity and mortality rates. We analyzed the correlation of peripheral arterial disease (PAD), here quantified by an abnormal ankle–brachial index (ABI) measured within the 5 years prior to kidney transplant, with graft failure and mortality rates (primary end points) after adjusting for known cardiovascular risk factors (age, sex, smoking history, hypertension, diabetes, stroke, known coronary artery disease or heart failure, years of dialysis). Of 1055 patients in our transplant population, 819 had arterial studies within the 5 years prior to transplant. Secondary end points included myocardial infarction; cerebrovascular accident; and limb ischemia, gangrene, or amputation. Low ABI was an independent and significant predictor of organ failure (OR, 2.77 (95% CI, 1.68–4.58), p<0.001), secondary end points (HR, 1.39 (95% CI, 0.97–1.99), p<0.076), and death (HR, 1.84 (95% CI, 1.26–2.68), p=0.002). PAD was common in this population: of 819 kidney transplant recipients, 46% had PAD. Low ABI was associated with a threefold greater risk of graft failure, a twofold greater risk of death after transplant, and a threefold greater risk of secondary end points. Screening for PAD is important in this patient population because of the potential impact on long-term outcomes.

Background Lower extremity peripheral arterial disease (PAD) is a common medical condition causing substantial morbidity. Limited data exist on whether discrepancies in PAD prevalence exist between the lower extremities using resting ankle-brachial indices (ABIs) and postexercise pressures. Objective We predicted the prevalence of PAD between the lower extremities. Methods and Results Consecutive patients who had undergone a noninvasive arterial lower extremity study at Mayo Clinic, Rochester, MN, between January 1996 and December 2012 with suspected PAD were retrospectively reviewed. We identified 12,312 consecutive patients who underwent an arterial lower extremity and an exercise treadmill study. Prevalence of PAD was assessed at rest and after exercise using two criteria: a resting ABI ≤ 0.90 and a postexercise pressure decrease of > 30 mm Hg. Mean age was 67 ± 12 years and there were 4,780 (39%) women studied. At rest, we found a higher prevalence of PAD on the left extremity (27.4%) compared with the right (24.6%) (p < 0.0001). After exercise, we found a higher prevalence of PAD on the right extremity (25.1%) compared with the left (19.0%) (p < 0.0001). These discrepancies between the prevalence of PAD at rest and after exercise were present in women and men. Conclusion Using validated criteria of a resting ABI of ≤ 0.90 and postexercise ankle pressure decrease > 30 mm Hg, our results suggest that there is a significantly higher prevalence of PAD in the left lower extremity at rest, in contrast to a greater prevalence of abnormal postexercise testing in the right lower extremity. The reason(s) of these discrepancies remain to be studied.

1. While the natriuretic peptides (atrial, brain and C-type) mediate potent endothelium-independent vasorelaxing actions in vitro, the role of the endogenous natriuretic peptide system in vascular regulation in vivo remains unclear. 2. HS-142-1 is a novel natriuretic peptide receptor antagonist derived from a fungus named Aureobasidium sp. which selectively blocks particulate guanylate cyclase-linked natriuretic peptide A and B receptors that bind atrial, brain and C-type natriuretic peptide, and thus attenuates the generation of cGMP. 3. To characterize the vascular actions of the endogenous natriuretic peptide system in the control of basal coronary and systemic haemodynamics, six normal male mongrel anaesthetized dogs were studied while a second group of five dogs served as a control. HS-142-1 was given as an intravenous bolus at 3 mg/kg and was studied over five 20 min periods. 4. No significant difference after HS-142-1 was observed in mean arterial pressure, heart rate, cardiac output, right atrial pressure, pulmonary capillary wedge pressure or systemic vascular resistance compared with control. In contrast, a significant increase in coronary vascular resistance and decrease in coronary blood flow were observed which were different from the baseline values and the responses of the control group. 5. These studies demonstrate that HS-142-1 produces vasoconstriction in the coronary circulation. We conclude that the endogenous natriuretic peptide system, which is of cardiac and endothelial cell origin, is an important regulator of basal coronary vascular tone.