INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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Clinical Trial
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Proximal Embolic Protection May Be Superior to Distal Protection for SVG Lesions.
Embolic complications during stenting of saphenous vein graft (SVG) lesions are reduced, but not eliminated, by distal protection devices; some of these emboli may be released by passage of the device through the diseased segment. The PROXIMAL trial tested a new system that is deployed proximally to the lesion; antegrade flow through the vessel is occluded by a balloon and the debris is aspirated after stent deployment. Patients were randomized to either the new device or standard distal protection. In this small, noninferiority trial there were no statistical differences in the rate of major adverse cardiac events at 30 days; however, many of the trends favored proximal protection. See page 1442. See figure.
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Acute Coronary Syndromes
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CD4+CD28null T Lymphocytes May Increase Plaque Instability.
Previous work has shown that patients with unstable angina (UA) have an increased frequency of CD4+ T lymphocytes with defective expression of CD28; these cells seem to release large amounts of interferon- , which may activate monocytes and macrophages. Liuzzo and colleagues measured the number of these cells in patients presenting with UA. CD4+CD28null T-cell frequency was higher in patients with multiple admissions for UA than in those with one or no admissions (control patients with coronary artery disease). On multivariate logistic regression analysis, CD4+CD28null T-cell frequency was an independent predictor of future acute coronary events. The expansion of CD4+CD28null T cells may play a pathogenic role in converting stable plaques into unstable lesions. See page 1450. See figure.
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Cardiac Imaging
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The Prognostic Utility of MSCT Depends on Pretest Probability of CAD.
The clinical utility of a test result requires knowledge of the sensitivity and specificity of the test as well as an assessment of the pretest probability. Meijboom and colleagues calculated the pretest probability for significant coronary artery disease (CAD) in 254 symptomatic patients based on the type of chest discomfort and their risk factors. All subjects had both multislice computed tomography (MSCT) and traditional angiography. The post-test probability of significant CAD after a negative CT scan was 17% in the high-risk group versus 0% for the low- and intermediate-risk groups. After a positive MSCT test result, 96% of high-risk patients had significant CAD versus only 68% in the low-risk group. The authors conclude that MSCT is useful in symptomatic patients with a low or intermediate pretest probability of significant CAD, and a negative CT scan reliably rules out CAD in this group. However, there is limited utility of MSCT in patients with a high pretest probability of CAD. See page 1469. See figure.
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Cardiac Resynchronization Therapy
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Animal Model Questions Benefit of CRT in Patients With RBBB.
Cardiac resynchronization therapy (CRT) is effective for patients with discordant contraction, although most data pertains to left bundle branch block (LBBB) delays. With right bundle branch block (RBBB), the lateral wall contracts early so that left ventricular (LV) pre-excitation may not be needed. Byrne and colleagues used radiofrequency ablation to induce either LBBB or RBBB in dogs with tachycardia-induced LV dysfunction. Cine magnetic resonance imaging and micromanometer catheters were then used to compare different pacing modes. Despite similar QRS widening and LV function, mechanical dyssynchrony was less in RBBB. Cardiac resynchronization therapy had correspondingly less effect on hearts with RBBB than those with LBBB. This study suggests limited benefits to CRT in patients with RBBB. See page 1484. See figure.
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Congenital Heart Disease
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RV Restrictive Filling Predicts Symptoms in Patients With Pulmonic Stenosis.
Lam and colleagues previously reported that antegrade pulmonary arterial (PA) flow in late diastole occurs when right ventricular (RV) end-diastolic pressure exceeds PA diastolic pressure. This flow suggests poor compliance of the RV or restrictive RV physiology. For this study, the prevalence of RV restrictive filling was studied in subjects with moderate to severe isolated pulmonic stenosis (PS). Forty-two percent of patients had restrictive RV physiology; these patients were more symptomatic. Restrictive RV physiology appears to be common in PS patients and correlates with decreased exercise tolerance. See page 1491. See figure.
Related Articles
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The PROXIMAL Trial: Proximal Protection During Saphenous Vein Graft Intervention Using the Proxis Embolic Protection System: A Randomized, Prospective, Multicenter Clinical Trial
- Laura Mauri, David Cox, James Hermiller, Joseph Massaro, Joyce Wahr, Sew Wah Tay, Michael Jonas, Jeffrey J. Popma, Jim Pavliska, Dennis Wahr, and Campbell Rogers
J. Am. Coll. Cardiol. 2007 50: 1442-1449.
[Abstract]
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Unusual CD4+CD28null T Lymphocytes and Recurrence of Acute Coronary Events
- Giovanna Liuzzo, Luigi M. Biasucci, Graziana Trotta, Salvatore Brugaletta, Michela Pinnelli, Giovanna Digianuario, Vittoria Rizzello, Antonio G. Rebuzzi, Carlo Rumi, Attilio Maseri, and Filippo Crea
J. Am. Coll. Cardiol. 2007 50: 1450-1458.
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64-Slice Computed Tomography Coronary Angiography in Patients With High, Intermediate, or Low Pretest Probability of Significant Coronary Artery Disease
- W. Bob Meijboom, Carlos A.G. van Mieghem, Nico R. Mollet, Francesca Pugliese, Annick C. Weustink, Niels van Pelt, Filippo Cademartiri, Koen Nieman, Eric Boersma, Peter de Jaegere, Gabriel P. Krestin, and Pim J. de Feyter
J. Am. Coll. Cardiol. 2007 50: 1469-1475.
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Diminished Left Ventricular Dyssynchrony and Impact of Resynchronization in Failing Hearts With Right Versus Left Bundle Branch Block
- Melissa J. Byrne, Robert H. Helm, Samantapudi Daya, Nael F. Osman, Henry R. Halperin, Ronald D. Berger, David A. Kass, and Albert C. Lardo
J. Am. Coll. Cardiol. 2007 50: 1484-1490.
[Abstract]
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Restrictive Right Ventricular Physiology: Its Presence and Symptomatic Contribution in Patients With Pulmonary Valvular Stenosis
- Yat-Yin Lam, Mehmet G. Kaya, Omer Goktekin, Michael A. Gatzoulis, Wei Li, and Michael Y. Henein
J. Am. Coll. Cardiol. 2007 50: 1491-1497.
[Abstract]
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Clinical Trial
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