INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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Interventional Cardiology
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Switching From Heparin or Enoxaparin to Bivalirudin Reduces Bleeding Complications.
The ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) trial demonstrated that bivalirudin reduced bleeding complications compared to both unfractionated heparin (UFH) and enoxaparin plus a glycoprotein IIb/IIIa inhibitor in patients having intervention. However, there is concern that switching from one regimen to another may increase bleeding complications. In the ACUITY trial, patients switched to bivalirudin had similar rates of ischemia, but were only one-half as likely to have major bleeding as those who remained on UFH/enoxaparin. Similar results were found in patients who were not pre-treated with UFH or enoxaparin. These results suggest that bivalrudin consistently reduces bleeding complications and may be used even when patients have already received either UFH or enoxaparin. See page 1734. See figure.
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Vascular Disorders
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Statins Appear to Be Beneficial for Coronary Spasm.
Recent evidence suggests that endothelial dysfunction is important for the pathophysiology of coronary spasm. The SCAST (Statin and Coronary Artery Spasm Trial) studied 64 patients who had spasm provoked by the intracoronary administration of acetylcholine (Ach). Subjects were then treated with a calcium-channel blocker and one-half were randomized to also receive fluvastatin. The Ach challenge was repeated after 6 months. Fluvastatin significantly reduced the number of coronary segments with induced spasm. The addition of fluvastatin appears to reduce coronary spasm although the mechanism is unclear. See page 1742. See figure.
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Vascular Disorders
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Significant Interactions Found Between Endothelium and Thrombin Receptor.
Thrombin is central to the coagulation cascade and also induces vascular effects via protease-activated receptor type 1 (PAR-1). Gumundsdóttir and colleagues performed a series of elegant experiments to identify the effects of thrombin on the vasculature using SFLLRN which is a peptide that mimics activation of the PAR-1 receptor. The PAR-1 activation was found to induce arterial vasodilation, which required a functioning endothelium, and venoconstriction, which was endothelium independent. These findings provide evidence of a major interaction between the endothelium and thrombin in vivo. See page 1749.
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Heart Failure
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Obesity and Inflammation Predict Risk of New Onset CHF.
Although obesity is considered a risk factor for congestive heart failure (CHF), the mechanisms remain unclear. Bahrami and colleagues used data from the MESA (Multi-Ethnic Study of Atherosclerosis) study to identify risk factors for new onset CHF. The absolute risk of CHF in nonobese participants was 10 in 1,000, this risk increased to 16 in 1,000 for obese participants. While obesity was associated with incident CHF, this association was no longer significant after adding inflammatory markers (interleukin-6 or C-reactive protein) to the multivariable model. These results suggest that the link between obesity and CHF may be higher levels of inflammation. See page 1775.
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Heart Rhythm Disorders
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Atrial Fibrillation Leads to Prothrombotic State.
In order to determine whether atrial fibrillation (AF) causes platelet activation, Akar and colleagues collected blood samples from the coronary sinus of patients before and after 15 min of intentionally induced AF. These results were compared to a control group that underwent right atrial pacing without inducing AF. In AF patients, but not controls, there was increased platelet expression of P-selectin, increased thrombin production, and decreased nitric oxide formation. These findings show that AF causes local cardiac platelet activation within minutes of onset and demonstrates how AF may contribute to a hypercoagulable state. See page 1790.
Related Articles
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Safety and Efficacy of Switching From Either Unfractionated Heparin or Enoxaparin to Bivalirudin in Patients With Non–ST-Segment Elevation Acute Coronary Syndromes Managed With an Invasive Strategy: Results From the ACUITY (Acute Catheterization and Urgent Intervention Triage strategY) Trial
- Harvey D. White, Derek P. Chew, James W. Hoekstra, Chadwick D. Miller, Charles V. Pollack, Jr, Frederick Feit, A. Michael Lincoff, Michel Bertrand, Stuart Pocock, James Ware, E. Magnus Ohman, Roxana Mehran, and Gregg W. Stone
J. Am. Coll. Cardiol. 2008 51: 1734-1741.
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Effects of a 3-Hydroxy-3-Methylglutaryl Coenzyme A Reductase Inhibitor, Fluvastatin, on Coronary Spasm After Withdrawal of Calcium-Channel Blockers
- Hirofumi Yasue, Yuji Mizuno, Eisaku Harada, Teruhiko Itoh, Hitoshi Nakagawa, Masafumi Nakayama, Hisao Ogawa, Shinji Tayama, Takasi Honda, Seiji Hokimoto, Shuichi Ohshima, Youichi Hokamura, Kiyotaka Kugiyama, Minoru Horie, Michihiro Yoshimura, Masaki Harada, Shiroh Uemura, Yoshihiko Saito for the SCAST (Statin and Coronary Artery Spasm Trial) Investigators
J. Am. Coll. Cardiol. 2008 51: 1742-1748.
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Role of the Endothelium in the Vascular Effects of the Thrombin Receptor (Protease-Activated Receptor Type 1) in Humans
- Ingibjörg J. Guðmundsdóttir, Ninian N. Lang, Nicholas A. Boon, Christopher A. Ludlam, David J. Webb, Keith A. Fox, and David E. Newby
J. Am. Coll. Cardiol. 2008 51: 1749-1756.
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Novel Metabolic Risk Factors for Incident Heart Failure and Their Relationship With Obesity: The MESA (Multi-Ethnic Study of Atherosclerosis) Study
- Hossein Bahrami, David A. Bluemke, Richard Kronmal, Alain G. Bertoni, Donald M. Lloyd-Jones, Eyal Shahar, Moyses Szklo, and João A.C. Lima
J. Am. Coll. Cardiol. 2008 51: 1775-1783.
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Acute Onset Human Atrial Fibrillation Is Associated With Local Cardiac Platelet Activation and Endothelial Dysfunction
- Joseph G. Akar, Walter Jeske, and David J. Wilber
J. Am. Coll. Cardiol. 2008 51: 1790-1793.
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Interventional Cardiology
Vascular Disorders
