INSIDE THIS ISSUE OF JACC
Inside This Issue of JACC
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Interventional Cardiology
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DES May Impair Collateral Formation.
Meier and colleagues hypothesized that because drug-eluting stents (DES) delay healing of the endothelium, they may also delay the formation of collateral circulation that is normally stimulated by cytokines and growth factors released from the endothelium. A total of 120 patients who had received either a DES or a bare-metal stent were matched for the severity of in-stent restenosis and the time since stent implantation. The collateral flow index (CFI) was calculated by measuring the pressure in the vessel distal to the stent during balloon inflation inside the stent. The CFI was diminished in the DES group and patients with DES were more likely to have ST-segment elevation during balloon occlusion. This study suggests that DES may impair collateral formation up to 6 months after stent implantation. See page 15.
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Heart Failure
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Isosorbide Dinitrate/Hydralazine Safe With Low SBP.
Studies have shown that low systolic blood pressure (SBP) is a negative prognostic indicator in patients with congestive heart failure, and there is reluctance to start vasodilatory medications in patients with low blood pressure (BP) for fear of causing orthostasis. Anand and colleagues examined the role of SBP in the A-HeFT study. Although mortality was 2 times higher when the initial SBP was below the median of 126 mm Hg, the benefits of isosrbide dinitrate/hydralazine were apparent regardless of the starting BP. Whereas patients with low initial SBP were more likely to report dizziness with isosrbide dinitrate/hydralazine than with placebo, the discontinuation rates for low BP symptoms were not different. This study suggests that patients with systolic dysfunction and low BP can still benefit from vasodilator therapy. See pages 32 and 40. See figure.
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Heart Rhythm Disorders
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Microvolt T-Wave Alternans Identifies Patients Who Benefit From ICD Therapy.
Chow and colleagues collected the results of microvolt T-wave alternans (MTWA) testing from over 700 patients with ischemic cardiomyopathy (left ventricular ejection fraction <35%). One-half of these patients received implantable cardioverter-defibrillators (ICDs), but this was not randomized or dependent on the results of MTWA testing. For the two-thirds of patients who tested non-negative for MTWA, ICD implantation reduced the subsequent risk of death by over 50%. There was no benefit in those who tested negative. The number needed to treat with an ICD to save one life was 9 among MTWA-non-negative patients and 76 among MTWA-negative patients, suggesting that MTWA may be a useful method for determining which patients with ischemic cardiomyopathies should undergo ICD implantation. See pages 50 and 59.
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Thyroid Heart Disease
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Cardiovascular Effects of Hyperthyroidism Continue After Treatment.
Although it is generally recognized that hyperthyroidism can cause transient cardiovascular effects, little is known about the prevalence of these symptoms or whether these symptoms resolve as patients return to a euthyroid state. Osman and colleagues collected detailed information about cardiac symptoms in almost 400 patients with hyperthyroidism and compared them to a matched cohort. The same evaluations were then repeated as the thyroid abnormalities were treated. Patients with hyperthyroidism were much more likely to report symptoms of palpitations and dyspnea and approximately 8% had evidence of atrial fibrillation; they were also more likely to have a fall in systolic blood pressure upon standing. These differences remained even after patients were restored to a euthyroid state. Cardiovascular abnormalities are common in patients with overt hyperthyroidism at presentation, but some abnormalities persist despite effective antithyroid therapy. See page 71.
Related Article
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Coronary Collateral Function Long After Drug-Eluting Stent Implantation
- Pascal Meier, Rainer Zbinden, Mario Togni, Peter Wenaweser, Stephan Windecker, Bernhard Meier, and Christian Seiler
J. Am. Coll. Cardiol. 2007 49: 15-20.
[Abstract]
[Full Text]
[PDF]
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Interventional Cardiology
Heart Failure