INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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Myocardial Infarction and Stroke
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Not All PFOs Pose a Stroke Risk.
Sastry and colleagues sought to study the relationship between venous-to-arterial shunts and arterial embolic events. A total of 100 patients age 16 to 39 years who have had either a myocardial infarction (MI) or an ischemic stroke were compared to 100 controls. All subjects were evaluated for venous-to-arterial shunts with a transcranial Doppler protocol that detects microbubbles injected intravenously. Subjects were classified as no shunt, significant shunt, or major shunt based on the number of microbubbles that were detected in the arteries. There was no association between MI and shunt; only major shunts were associated with stroke which had an odds-ratio of almost 3. This study suggests that small venous-to-arterial shunts pose little risk for stroke or MI. See page 686. See figure.
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Invasive Cardiology
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Meta-Analysis Suggests Isosmolar is Superior to Low-Osmolar Contrast.
Previous studies have related the osmolarity of the angiographic contrast with the risk of contrast induced nephropathy (CIN), but the benefit afforded from isosmolar contrast media (IOCM, 290 mOsm/kg) compared to low-osmolar contrast media (LOCM, 600 to 800 mOsm/kg) has not been definitively proven. McCullough and colleagues pooled data from almost 3000 patients who had been randomized to either IOCM or LOCM for various intra-arterial procedures from 16 trials. IOCM use was associated with significantly smaller increases in postprocedure serum creatinine levels (0.06 mg/dl vs. 0.10 mg/dl). The difference was wider for higher risk patients such as those with baseline renal insufficiency or diabetes. CIN, defined strictly as an increase of serum creatinine >1 mg/dl, was approximately 10 times less with IOCM versus LOCM. This meta-analysis indicates that the supraphysiologic osmolarity of LOCM does induce some renal damage which can be reduced with isosmolar products. See page 698. See figure.
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Lipids and Cardiovascular Disease
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Reduced Cholesterol Absorption Associated With Improved Prognosis in Elderly Patients.
Researchers in Finland studied almost 400 elderly subjects with previous atherosclerotic events, to determine the prognostic value of measuring cholesterol absorption. Cholesterol absorption was assessed with the serum cholestanol to cholesterol concentration ratio; a lower level reflects decreased cholesterol absorption. After 4 years of follow-up, the baseline serum total and low-density lipoprotein-cholesterol levels did not predict future events, but risk did increase with increasing levels cholesterol absorption. Understanding the relationship between cholesterol absorption, cholesterol synthesis, and cardiovascular risk will improve our ability to identify patients at risk and find new targets for intervention. See page 708. See figure.
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Heart Rhythm Disorders
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Improved Quality of Life With Maintenance of Sinus Rhythm.
While it appears that there is no mortality benefit to using anti-arrhythmic medications to maintain sinus rhythm (SR) in patients with atrial fibrillation (AF), there is ongoing debate regarding its effects on symptoms. Singh and colleagues report on data collected from the SAFE-T trial that assigned patients to sotalol, amiodarone, or placebo. Rather than reporting the effect of any of these medications on quality of life (QOL), subjects were stratified by their rhythm at specified follow-up dates. Sinus rhythm was associated with improvements in most measures of QOL and with improved treadmill duration. The authors conclude that: "In patients with persistent AF, restoration and maintenance of SR was associated with improvements in QOL measures and exercise performance." See page 721. See figure.
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Heart Rhythm Disorders
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AV Node Ablation May Be Necessary for CRT Benefit in Patients With AF.
While cardiac resynchronization therapy (CRT) improves left ventricular (LV) function in patients with reduced ejection fraction and prolonged QRS, the utility of CRT in patients with atrial fibrillation (AF) is not clear. Gasparini and colleagues developed a protocol whereby the frequency of biventricular pacing was assessed in patients with AF and CRT. If, despite adequate rate-controlling medications the percentage of paced beats was <85%, patients were referred for atrioventricular node ablation. Over 4 years of follow-up, patients who had been ablated showed similar improvements in LV size and functional capacity as patients with sinus rhythm. Patients who remained in AF without undergoing ablation showed no improvements. This study suggests that patients with AF and other standard criteria for CRT should undergo AV nodal ablation at the time of CRT implantation. See page 734. See figure.
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Cardiac Imaging
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Utility of MDCT to Assess for CAD in Post-Cardiac Transplant Patients.
Most institutions that perform cardiac transplants specify that all subjects undergo annual coronary angiography to assess for asymptomatic coronary atherosclerosis which is the leading cause of death in patients who survive more than one year. While multi-detector computed tomography (MDCT) has shown acceptable accuracy in many patient groups, the cardiac denervation associated with transplantation often leads to mild tachycardias that are not responsive to beta-blockade and may interfere with the spatial resolution of MDCT. Sigurdsson and colleagues performed MDCT and coronary angiography in 54 transplant recipients. The average heart rate during the scan was 90 beats/min, yet 95% of the coronary segments were deemed analyzable by MDCT. MDCT correctly identified 15 of the 16 (94%) transplant patients classified by quantitative coronary angiography as having occlusive coronary artery disease and 29 of the 37 patients without significant stenosis (78%). This study suggests that MDCT may have a role in replacing annual coronary angiography in post-cardiac transplant patients. See page 772.
Related Article
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Young Adult Myocardial Infarction and Ischemic Stroke: The Role of Paradoxical Embolism and Thrombophilia (The YAMIS Study)
- Sanjay Sastry, Graham Riding, Julie Morris, David Taberner, Nicola Cherry, Anthony Heagerty, and Charles McCollum
J. Am. Coll. Cardiol. 2006 48: 686-691.
[Abstract]
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Myocardial Infarction and Stroke
Invasive Cardiology
