Circulation: Clinical Summaries
Original Research Put Into Perspective for the Practicing Clinician
- Central Sympathetic Inhibition to Reduce Postablation Atrial Fibrillation Recurrences in Hypertensive Patients: A Randomized, Controlled Study
- Prevalence and Prediction of Coronary Artery Disease in Patients With Liver Cirrhosis: A Registry-Based Matched Case–Control Study
- MHC Class II–Restricted Antigen Presentation by Plasmacytoid Dendritic Cells Drives Proatherogenic T Cell Immunity
- Diabetes Mellitus, Prediabetes, and Incidence of Subclinical Myocardial Damage
- Patient Access and 1-Year Outcomes of Percutaneous Coronary Intervention Facilities With and Without On-Site Cardiothoracic Surgery: Insights From the Veterans Affairs (VA) Clinical Assessment, Reporting, and Tracking (CART) Program
- Impact of Annual Operator and Institutional Volume on Percutaneous Coronary Intervention Outcomes: A 5-Year United States Experience (2005–2009)
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Central Sympathetic Inhibition to Reduce Postablation Atrial Fibrillation Recurrences in Hypertensive Patients: A Randomized, Controlled Study
Pulmonary vein isolation has become a mainstay in the treatment of atrial fibrillation (AF), especially drug-refractory AF. However, even in patients with paroxysmal AF, recurrence is not uncommon, especially after a single procedure. This prospective, controlled study showed that the addition of the centrally acting sympathoinhibitory agent moxonidine to standard antihypertensive treatment resulted in considerable reduction in recurrences, although there were no significant differences in blood pressure levels between the 2 treatment groups (standard antihypertensive treatment plus moxonidine or placebo) over the study follow-up. The hypothesis that this beneficial effect must be related to central inhibition of the sympathetic system is supported by existing evidence that triggering of AF episodes in paroxysmal AF involves a combined (simultaneous or sequential) activation of both limbs of the autonomic system. In this sense, it is a plausible suggestion that moxonidine disrupts the autonomic activation pattern, which has been shown to precede AF occurrences. Of note, the studied population included only patients with hypertension, and, as a result, extrapolation to nonhypertensive patients should be done with caution. However, the effect of moxonidine did not appear to be mediated by reductions in blood pressure, suggesting that this treatment could be of benefit for the general population of postablation patients (although this is only conjecture). In any case, given that hypertensive patients are a substantial subset of AF patients undergoing ablation (≈40% to 45% in recent series), the potential clinical benefit from moxonidine in this setting is of considerable import. See p 1346.
Prevalence and Prediction of Coronary Artery Disease in Patients With Liver Cirrhosis: A Registry-Based Matched Case–Control Study
There has been controversy over whether liver cirrhosis confers protection against coronary atherosclerosis or aggravates it. Because coronary artery disease (CAD) has a crucial impact on clinical prognosis in cirrhotic patients, especially after major surgery such as liver transplantation, it is very important to assess cardiovascular risk and prevent serious cardiac outcomes in these patients, especially during perioperative periods. In this large, registry-based, matched case–control study, we investigated the prevalence of silent CAD in asymptomatic patients with liver cirrhosis and matched controls with healthy livers, based on noninvasive computerized coronary angiographic images. We found that the prevalence of obstructive CAD was ≈8% in both cirrhotics and controls, although the former were at higher risk of nonobstructive CAD, which has a more benign course. In addition, obstructive or nonobstructive CAD was not related to liver function and coagulation parameters in the cirrhotic patients but to presumptive cardiovascular risk factors such as older age, male sex, hypertension, and diabetes mellitus, along with alcohol-related cirrhosis. Our comprehensive findings could provide important practical information relevant to cardiac workup specific for CAD, where a more rigorous type of workup should be considered in the presurgical period of cirrhotic patients displaying the above risk factor(s), in place of the current universal screening guidelines for individuals with normal livers, especially in the case of potential candidates for liver transplantation. See p 1353.
MHC Class II–Restricted Antigen Presentation by Plasmacytoid Dendritic Cells Drives Proatherogenic T Cell Immunity
Atherosclerosis is an inflammatory vascular disease driven in part by adaptive immune responses to low-density lipoprotein (LDL) cholesterol–derived antigens. The subtype of antigen-presenting cells responsible for activation of LDL-specific proatherogenic T cell responses has remained elusive. Plasmacytoid dendritic cells (pDCs) bridge innate and adaptive immune responses and are important regulators of immuno-inflammatory diseases. Here, we used genetic approaches to investigate the role of pDCs in atherosclerosis. We show that selective pDC deficiency in vivo reduces atherosclerosis in Ldlr–/– mice. To examine the role of antigen presentation by pDCs in atherosclerosis, we generated Ldlr–/– mice with selective MHCII deficiency in pDCs. Remarkably, these mice also developed reduced atherosclerosis compared with controls. The atheroprotective effect of selective MHCII deficiency in pDCs was associated with significant reductions of proatherogenic T cell–derived interferon-γ and lesional T cell infiltration, and was abrogated in CD4+ T cell–depleted animals. Because pDCs and T cells infiltrate both early and advanced atherosclerotic lesions in humans, we speculate that our results will also bear relevance to the human disease. However, direct testing of this hypothesis is still required, and additional studies are needed to determine the contribution of pDC-mediated immunity at later stages of disease development. In conclusion, we present new evidence that MHCII-restricted antigen presentation by pDCs drives proatherogenic T cell immunity. The results shed new light on the role of adaptive immune responses in atherosclerosis and may have implications for the design of specific therapeutic strategies. See p 1363.
Diabetes Mellitus, Prediabetes, and Incidence of Subclinical Myocardial Damage
Persons with prediabetes and diabetes mellitus are at high risk for cardiovascular events. However, the relationships of prediabetes and diabetes mellitus to the development of subclinical myocardial damage are unclear. We evaluated the associations of diabetes mellitus and prediabetes with the development of subclinical myocardial damage, as assessed by an incident elevation (≥14 ng/L) in cardiac troponin T measured with a highly sensitive assay during 6 years of follow-up. We also evaluated the subsequent risk of cardiovascular events and deaths by diabetes mellitus status among those persons with and without incident elevations in the high-sensitivity assay for cardiac troponin T. We found that both prediabetes and diabetes mellitus were independently associated with the development of subclinical myocardial damage. Furthermore, those persons with evidence of incident subclinical myocardial damage were at high risk for the future mortality and cardiovascular events, particularly heart failure. These results support a possible deleterious effect of hyperglycemia on the myocardium, possibly reflecting a microvascular cause. With the growing dual epidemics of obesity and diabetes mellitus, these results underscore the importance of preventing progression to early hyperglycemic states and the development of diabetes mellitus. Our results suggest that primary and secondary prevention of atherosclerotic disease in diabetes mellitus, for example via statin therapy, may not be sufficient to fully address the cardiac risk associated with hyperglycemic states. There is a possibility that the major improvements we have seen in cardiovascular morbidity and mortality over the past several decades may be disrupted by the epidemic of diabetes mellitus and prediabetes. See p 1374.
Patient Access and 1-Year Outcomes of Percutaneous Coronary Intervention Facilities With and Without On-Site Cardiothoracic Surgery: Insights From the Veterans Affairs (VA) Clinical Assessment, Reporting, and Tracking (CART) Program
The safety of percutaneous coronary intervention (PCI) at medical facilities without on-site cardiothoracic (CT) surgery has been established in clinical trials. However, the comparative effectiveness of this strategy in real-world practice, including impact on patient access and outcomes, is uncertain. The Veterans Affairs (VA) health care system has used this strategy, with strict quality oversight, since 2005, and can provide insight into this question. Eighteen of 59 PCI facilities in the VA system do not have on-site CT surgery and performed PCI on 6616 (27.1%) of 24 387 patients receiving PCI in the VA system between October 2007 and September 2010. The availability of these 18 facilities reduced the median drive time of patients to the nearest PCI facility by 90.8 minutes. Compared with PCI facilities with on-site CT surgery, similar rates of procedural adverse outcomes and 1-year mortality and MI rates were seen at facilities without on-site CT surgery. The findings were not modified by either PCI indication or PCI volume. This study suggests that providing PCI facilities without on-site CT surgery in an integrated health care system with quality oversight improves patient access without comprising procedural or 1-year outcomes. See p 1383.
Impact of Annual Operator and Institutional Volume on Percutaneous Coronary Intervention Outcomes: A 5-Year United States Experience (2005–2009)
There has been a recent decline in total number of percutaneous coronary interventions (PCIs) performed. Many interventional cardiologists and hospitals have therefore experienced a fall in procedural volumes. The current clinical competency guidelines are primarily based on expert opinion because there is paucity of data regarding effects of operator or institutional volume on outcomes. We assessed the current recommendations in this cross-sectional study consisting of 457 498 PCI procedures (representing a total of 2 243 209 PCIs performed in the United States during 2005–2009) from multiple hospitals across the nation. We found that procedures performed by high-volume operators and at high-volume institutions have significant impact on mortality, complications, length of hospital stay, and hence the total cost of in-hospital care. We also report other patient- and hospital-related factors affecting the outcomes during PCI-related hospitalizations. See p 1392.
- © 2014 American Heart Association, Inc.
- Diabetes Mellitus, Prediabetes, and Incidence of Subclinical Myocardial Damage
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