Circulation: Clinical Summaries
Original Research Put Into Perspective for the Practicing Clinician
- Association Between Maternal Chronic Conditions and Congenital Heart Defects: A Population-Based Cohort Study
- Participation in Cardiac Rehabilitation and Survival After Coronary Artery Bypass Graft Surgery: A Community-Based Study
- Cocaine-Induced Vasoconstriction in the Human Coronary Microcirculation: New Evidence From Myocardial Contrast Echocardiography
- Stress Cardiac Magnetic Resonance Imaging Provides Effective Cardiac Risk Reclassification in Patients With Known or Suspected Stable Coronary Artery Disease
- Drug-Eluting Balloon in Peripheral Intervention for Below the Knee Angioplasty Evaluation (DEBATE-BTK): A Randomized Trial in Diabetic Patients With Critical Limb Ischemia
- Impact of Aortic Valve Replacement on Outcome of Symptomatic Patients With Severe Aortic Stenosis With Low Gradient and Preserved Left Ventricular Ejection Fraction
- Sterol Regulatory Element Binding Protein 2 Activation of NLRP3 Inflammasome in Endothelium Mediates Hemodynamic-Induced Atherosclerosis Susceptibility
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Association Between Maternal Chronic Conditions and Congenital Heart Defects: A Population-Based Cohort Study
This Canadian study attempted to quantify the association between maternal medical conditions/illnesses and congenital heart defects (CHDs) among infants. The analysis was based on a large population-based cohort of 2 278 838 mother-infant pairs, including infants with CHDs diagnosed at birth or at rehospitalization any time in infancy. The prevalence of CHDs in Canada (excluding Quebec) was 116.2 cases per 10 000 live births, and the overall trend in CHDs declined from 2002 to 2010. Several maternal characteristics and conditions were strongly associated with CHDs in the offspring. Risk factors for CHD included maternal age ≥40 years (adjusted odds ratio [aOR], 1.48; 95% confidence interval [CI], 1.39–1.58), multifetal pregnancy (aOR, 4.53; 95% CI, 4.28–4.80), diabetes mellitus (type 1: aOR, 4.65; 95% CI, 4.13–5.24; type 2: aOR, 4.12; 95% CI, 3.69–4.60), hypertension (aOR, 1.81; 95% CI, 1.61–2.03), thyroid disorders (aOR, 1.45; 95% CI, 1.26–1.67), congenital heart disease (aOR, 9.92; 95% CI, 8.36–11.8), systemic connective tissue disorders (aOR, 3.01; 95% CI, 2.23–4.06), and epilepsy and mood disorders (aOR, 1.41; 95% CI, 1.16–1.72). Approximately 4.8% and 2.6% of the CHD cases could be attributed to multifetal pregnancy and maternal age ≥35 years, respectively, at the population level. As a whole, 14% of those CHD cases could be prevented if the above-mentioned risk factors were eliminated from the population. Understanding these relationships and probable causes may provide an opportunity to promote preconception health and primary prevention and help to facilitate targeted screening for lethal and very severe heart defects. See p 583.
Participation in Cardiac Rehabilitation and Survival After Coronary Artery Bypass Graft Surgery: A Community-Based Study
Cardiac rehabilitation (CR) is a program of structured exercise training, aggressive risk factor control, and lifestyle management for patients recovering from a recent cardiac event. There is strong evidence from both randomized controlled trials and observational studies that CR reduces mortality among patients with myocardial infarction and percutaneous coronary intervention; however, the evidence is less well established among patients with coronary artery bypass graft (CABG) surgery, and there has been some recent controversy about the effectiveness of CR. No randomized controlled trial has ever specifically tested CR among patients with CABG. Observational studies have either been small or limited to elderly patients. Consequently, we performed a community-based detailed analysis of the long-term, all-cause mortality changes associated with CR participation after CABG in 846 mixed-age patients. After 10 years of follow-up, CR attendance was associated with a 45% reduction in long-term mortality. Our findings support national guidelines that strongly recommend referral to CR for all patients after CABG. See p 590.
Cocaine-Induced Vasoconstriction in the Human Coronary Microcirculation: New Evidence From Myocardial Contrast Echocardiography
Cocaine is the second most widely abused drug in the world (second only to marijuana) and constitutes a major cause of cardiovascular disease, especially acute coronary syndrome. The incidence of cocaine-induced acute coronary syndrome has increased steadily over the last 2 decades as cocaine use has increased worldwide. Treatment of cocaine-induced acute coronary syndrome, however, remains largely empirical because the underlying pathogenesis is incompletely understood and an efficient method to evaluate putative countermeasures is lacking. Using myocardial contrast echocardiography in cocaine-naïve healthy young adults, we show that a nonintoxicating low-dose intranasal cocaine challenge evokes a sizeable decrease in myocardial perfusion. Moreover, the predominant effect is to decrease myocardial capillary blood volume rather than microvascular flow velocity, suggesting a specific action of cocaine to constrict terminal feed arteries. These findings establish myocardial contrast echocardiography as an efficient, noninvasive method for future studies to elucidate the underlying mechanism of cocaine-induced coronary vasoconstriction and to evaluate potential countermeasures in a controlled clinical research setting. See p 598.
Stress Cardiac Magnetic Resonance Imaging Provides Effective Cardiac Risk Reclassification in Patients With Known or Suspected Stable Coronary Artery Disease
Recent results from the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial suggest that an initial strategy of mechanical reperfusion may not improve cardiac outcomes beyond optimized medical therapy in patients with stable coronary artery disease (CAD). Nevertheless, a subgroup of patients with significant myocardial ischemia may still benefit from coronary revascularization, and current practice guidelines recommend that CAD patients at high risk for adverse events be considered for revascularization. Given increasing concern over effective resource utilization in cardiac imaging, establishing evidence indicating how cardiac imaging successfully influences clinical decision making is imperative. We studied 815 consecutive patients referred for evaluation of myocardial ischemia by stress cardiac magnetic resonance imaging, finding that inducible ischemia had the strongest association with major adverse cardiovascular events that include cardiac death or myocardial infarction after adjustment for clinical predictors, previous CAD, and left ventricular ejection fraction. Absence of inducible ischemia by cardiac magnetic resonance imaging was associated with low annual rate of events in the entire population and in a subgroup with CAD. Adding inducible ischemia to a clinical risk model reclassified >90% of patients at moderate pretest risk, with corresponding observed event rates of 0.3%/y and 4.9%/y for low- and high-risk posttest groups, respectively. These results demonstrate that cardiac magnetic resonance imaging effectively reclassifies risk beyond clinical risk predictors, specifically in the moderate pretest risk subgroup and in patients with previous CAD. Stress cardiac magnetic resonance imaging offers an effective strategy to safely manage some patients without the need for invasive angiography. See p 605.
Drug-Eluting Balloon in Peripheral Intervention for Below the Knee Angioplasty Evaluation (DEBATE-BTK): A Randomized Trial in Diabetic Patients With Critical Limb Ischemia
Critical limb ischemia, characterized by ischemic rest pain or tissue loss, represents the most advanced state of peripheral artery disease, burdened by extremely high morbidity and mortality. Critical limb ischemia generally occurs in diabetics with extensive atherosclerotic disease of the below-the-knee vessels. The optimal strategy for treating critical limb ischemia patients, however, has not been clearly defined, and the 1-year restenosis rate after balloon angioplasty (percutaneous transluminal angioplasty) of long lesions in below-the-knee arteries may be as high as 70%. The Drug-Eluting Balloon in Peripheral Intervention for Below the Knee Angioplasty Evaluation (DEBATE-BTK) is the first randomized study evaluating the efficacy, in terms of 12-month restenosis and target lesion revascularization, of drug-eluting balloons compared with standard percutaneous transluminal angioplasty in diabetic patients with de novo long atherosclerotic lesions and critical limb ischemia undergoing revascularization of below-the-knee arteries. Our study demonstrates that the drug-eluting balloons significantly reduced 12-month restenosis, regardless of lesion length, revascularization technique, and baseline vessel conditions. The advantage conferred by drug-eluting balloons on restenosis resulted in a significant decrease in clinically driven target lesion revascularization, and this benefit is further compounded by the more favorable distribution of Rutherford classes at follow-up and faster index ulcer healing in the drug-eluting balloon group. See p 615.
Impact of Aortic Valve Replacement on Outcome of Symptomatic Patients With Severe Aortic Stenosis With Low Gradient and Preserved Left Ventricular Ejection Fraction
Severe aortic stenosis (AS) is defined echocardiographically by an aortic valve area ≤1 cm2 (indexed aortic valve area ≤0.6 cm2/m2) and a mean transvalvular gradient ≥40 mm Hg. Because symptoms of AS may be caused by other common comorbidities in the elderly, decision making about the management of AS can be difficult when discrepancies occur between aortic valve area and mean transvalvular gradient. In particular, when mean transvalvular gradient is only moderate but aortic valve area is consistent with severe AS, the clinician may be reluctant to base a decision on aortic valve area because this derived measurement is susceptible to inaccuracy and because the gradient may be perceived as being not much greater than that of a prosthetic valve. Although patients with reduced left ventricular ejection fraction have traditionally been associated with severe AS and a low gradient, this condition may also occur with preserved ejection fraction with either reduced or preserved stroke volume. There are limited reports of the outcome of these patients with surgery and medical management. The present study compared the outcome of 123 patients treated with aortic valve replacement and 137 medically treated symptomatic patients with low-gradient severe AS with a low transvalvular mean gradient (29.1±5.3 mm Hg) despite preserved left ventricular ejection fraction (60.2±7.1%). A propensity score was created to explore the independent effects of aortic valve replacement. The main findings were that aortic valve replacement was independently associated with better outcome in patients with low-gradient severe AS and that the magnitude of benefit of aortic valve replacement was not associated with stroke volume. These results suggest that if symptomatic low-gradient severe AS is confirmed after the exclusion of possible measurement errors, aortic valve replacement is associated with better survival, irrespective of the flow pattern. See p 622.
Sterol Regulatory Element Binding Protein 2 Activation of NLRP3 Inflammasome in Endothelium Mediates Hemodynamic-Induced Atherosclerosis Susceptibility
Atherosclerosis preferentially develops at branches and curvatures in the arterial tree, and the disturbed flow pattern imposed in the endothelium in these regions plays a major role in the preferentially localized atherosclerosis. In this study, we show that disturbed flow increases endothelial innate immunity via NLRP3 inflammasome in vitro and in vivo. The underlying mechanism involves the induction of sterol regulatory element binding protein 2 (SREBP2), which transactivates NADPH oxidase 2 and NLRP3. The increased innate immunity in endothelium predisposes hyperlipidemia to result in the focal nature of atherosclerosis. This newly defined SREBP2/NLRP3 inflammasome pathway suggests that SREBP2 could be a therapeutic target to prevent atherosclerosis initiation, which is in line with the antiatherosclerosis effect of interleukin-1β antagonism. See p 632.
- © 2013 American Heart Association, Inc.
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