Circulation: Clinical Summaries
Original Research Put Into Perspective for the Practicing Clinician
- Randomized, Controlled Trial of the Safety and Effectiveness of a Contact Force–Sensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study
- Utility of Nontraditional Risk Markers in Individuals Ineligible for Statin Therapy According to the 2013 American College of Cardiology/American Heart Association Cholesterol Guidelines
- Impact of Diabetes Mellitus on Hospitalization for Heart Failure, Cardiovascular Events, and Death: Outcomes at 4 Years From the Reduction of Atherothrombosis for Continued Health (REACH) Registry
- Downregulation of MicroRNA-126 Contributes to the Failing Right Ventricle in Pulmonary Arterial Hypertension
- Caval Penetration by Inferior Vena Cava Filters: A Systematic Literature Review of Clinical Significance and Management
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Randomized, Controlled Trial of the Safety and Effectiveness of a Contact Force–Sensing Irrigated Catheter for Ablation of Paroxysmal Atrial Fibrillation: Results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) Study
A major advancement in the field of atrial fibrillation ablation has been the advent of radiofrequency ablation catheters with the capability of sensing the contact force (CF) between the catheter tip and tissue. It would stand to reason that knowledge of CF would allow more optimal lesion delivery during atrial fibrillation ablation and improve procedural efficacy. Here, we report the results of the TactiCath Contact Force Ablation Catheter Study for Atrial Fibrillation (TOCCASTAR) trial, a multicenter, prospective trial that randomized 300 patients with paroxysmal atrial fibrillation to ablation with a CF-sensing catheter or to a standard radiofrequency ablation catheter in the control group. Primary effectiveness at 12 months was 67.8% in the CF group and 69.4% in the control group (P=0.0073 for noninferiority), which met criteria for noninferiority, and safety was not different between the groups. These results are not surprising, given that operators were not given CF guidelines for ablation. During this trial, CF guidelines based on results from other concurrent studies become available, prompting a retrospective analysis of the data. When the CF group was divided into an optimal group (≥90% ablations with ≥10 g) and a nonoptimal group, primary effectiveness was 75.9% versus 58.1% (P=0.018), respectively. These results demonstrate the clear benefit of good contact between catheter and tissue during atrial fibrillation ablation, which may improve procedural efficacy. See p 907.
Utility of Nontraditional Risk Markers in Individuals Ineligible for Statin Therapy According to the 2013 American College of Cardiology/American Heart Association Cholesterol Guidelines
The 2013 American College of Cardiology/American Heart Association cholesterol guidelines recommended using additional risk markers at specific thresholds to help with clinical decision making in selected individuals who are not in 1 of the 4 statin-benefit groups and for whom a decision to initiate statin therapy is otherwise unclear (Class II). The markers mentioned included low-density lipoprotein cholesterol ≥160 mg/dL; other genetic hyperlipidemias; family history of premature atherosclerotic cardiovascular disease (ASCVD); high-sensitivity C-reactive protein ≥2 mg/dL; coronary artery calcium score ≥300 Agatston units or ≥75th percentile for age, sex, and ethnicity; lifetime ASCVD risk; and ankle-brachial index <0.9. Prospective data from participants of the Multi-Ethnic Study of Atherosclerosis and 10-year adjudicated ASCVD events were used to assess the yield of this recommendation in those with <7.5% 10-year risk. Using a calibrated Pooled Cohort Equation, we showed that majority (57%) of the ASCVD events occurred in those who were not statin eligible (10-year calibrated Pooled Cohort Equation–estimated risk <7.5% at baseline), emphasizing the need for further ASCVD risk stratification in this subgroup in the population. This was not the case when the actual Pooled Cohort Equation (not calibrated) was used (only 16% ASCVD events occurred). Abnormal results of coronary artery calcium, high-sensitivity C-reactive protein, and family history of ASCVD (above the recommended thresholds) resulted in revised higher risk estimates in small subcohorts of the group with <7.5% risk estimated by the calibrated Pooled Cohort Equation. The yield of genetic hyperlipidemia and lifetime ASCVD risk was not evaluated in this analysis. See p 916.
Impact of Diabetes Mellitus on Hospitalization for Heart Failure, Cardiovascular Events, and Death: Outcomes at 4 Years From the Reduction of Atherothrombosis for Continued Health (REACH) Registry
This analysis of patients with diabetes mellitus from the Reduction of Atherothrombosis for Continued Health (REACH) registry, an international study of patients at high risk of atherothrombosis or established atherothrombosis, found that cardiovascular events were more frequent in patients with diabetes mellitus. In the current era, 1 of 6 patients with diabetes mellitus in the REACH registry experienced a cardiovascular death, myocardial infarction, or stroke during 4 years of follow-up. Thus, the presence of diabetes mellitus continues to be a significant risk factor for ischemic events despite the use of evidence-based therapies in a contemporary, international cohort of patients. In addition, the presence of diabetes mellitus was associated with a 33% greater odds of hospitalization for heart failure. This risk was present both in patients with diabetes mellitus and established atherosclerosis and in those with diabetes mellitus and only risk factors for atherosclerosis. The association between diabetes mellitus and heart failure was seen in patients with prior ischemic events (myocardial infarction, stroke), diabetes mellitus and known atherothrombosis but no prior ischemic events, and those with diabetes mellitus with risk factors only for atherothrombosis. These findings suggest that it is possible that the mechanism of the association between diabetes mellitus and heart failure could be related to a process specific to patients with diabetes mellitus rather than an increased burden of atherothrombosis. In an era in which there is increasing emphasis on chronic disease management, these findings highlight the significance of diabetes mellitus and the continued need for therapies that improve outcomes in this high-risk population. See p 923.
Downregulation of MicroRNA-126 Contributes to the Failing Right Ventricle in Pulmonary Arterial Hypertension
Despite recent therapeutic advances, pulmonary arterial hypertension (PAH) remains a devastating disease, with a 3-year survival of 55% to 65%. Although the initial insult involves the pulmonary vasculature, survival of patients with PAH is determined predominantly by the response of the right ventricle (RV) to the increased afterload. Although elevated afterload is responsible for RV failure in PAH, the progressive decline in RV function is a multifaceted disease process. Significant interindividual variability is observed in RV adaptation, suggesting that disease-specific myocardial involvement likely contributes to cardiac dysfunction in PAH. Disorders of metabolism, adrenergic signaling, contractile function, and angiogenesis have been proposed as determinants of RV failure in PAH. However, little is known about the molecular mechanisms involved or, more important, about RV-specific interventions that could preserve RV function in PAH. Using a translational approach, we provide evidence that RV failure in human PAH is associated with microRNA-126 downregulation, accounting for capillary rarefaction within the RV and the transition from compensated to decompensated RV. Our findings also show that microRNA-126 modulation restores the PAH RV endothelial cell angiogenic potential in vitro, as well as RV microvascular density and function in vivo. The present study thus confirms the implication of microRNAs and capillary rarefaction in the cause of RV failure in human PAH. More important, the present study confirms that RV failure in PAH is potentially reversible through cardiac-targeted therapies. Consequently, modulation of RV angiogenesis represents a novel and attractive therapeutic target while we await the development of PAH therapies that reduce RV afterload more effectively. See p 932.
Caval Penetration by Inferior Vena Cava Filters: A Systematic Literature Review of Clinical Significance and Management
Limited caval penetration is required to secure inferior vena cava filters to the caval wall; however, unintended progressive caval penetration can also cause complications, resulting in pain, bleeding, or other potential serious conditions. Frequently underrecognized by clinicians, the penetration rate can be as high as 33.9% on the basis of our study results, and 19.0% of those penetrations showed evidence of organ/structure involvement on computed tomography scan. Indeed, symptomatic patients accounted for nearly 1/10th of all penetrations. Interventions with unplanned endovascular treatment or filter retrieval with or without surgery was required in 4.8% of all penetrations. Although endovascular retrieval of the symptomatic filter is the treatment of choice, open surgery may be required for permanent filters or for high-risk patients. Conservative management can be pursued if the filter is still clinically indicated or if removal is not possible. A temporary or optional filter might be preferred over permanent filters because retrievable filters offer the option to treat the complication once an adverse event occurs. A filter with symptomatic penetration or a severely penetrated but clinically asymptomatic filter should be removed, particularly those filters with organ or structure violation. See p 944.
- © 2015 American Heart Association, Inc.
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