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CARDIOVASCULAR NEWS
Year : 2005  |  Volume : 6  |  Issue : 3  |  Page : 90-92 Table of Contents     

Cardiovascular News


Date of Web Publication18-Jun-2010

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How to cite this article:
. Cardiovascular News. Heart Views 2005;6:90-2

How to cite this URL:
. Cardiovascular News. Heart Views [serial online] 2005 [cited 2020 Aug 10];6:90-2. Available from: http://www.heartviews.org/text.asp?2005/6/3/90/64018

Relationship between procedure indications and outcomes of percutaneous coronary interventions

An American College of Cardiology/American Heart Association (ACC/AHA) Task Force periodically revises and publishes guidelines with evidence-based recommendations for appropriate use of percutaneous coronary intervention (PCI). Some studies have suggested that closer adherence to guidelines can reduce variations in care, can improve quality, and may ultimately result in better outcomes, but this finding is incompletely understood. Guidelines themselves must change to be responsive to continuously evolving clinical practice. Our goal here was to investigate whether any relationship existed between the most recent ACC/AHA recommended indications for PCI and short term in-hospital outcomes.

The ACC National Cardiovascular Data Registry for the period of January 1, 2001, through March 31, 2004 was analyzed. We excluded PCI procedures performed for acute myocardial infarction (ST-segment elevation myocardial infarction); all others were grouped by their indications according to the standard ACC/AHA scheme: Class I, evidence and/or agreement that PCI is useful and effective; Class IIa, conflicting evidence and/or divergent opinions, weight is in favor; Class IIb, usefulness/efficacy is less well established; and Class III, evidence and/or agreement that PCI is not useful or effective and may be harmful.

Clinical success was defined as angiographic success (<20% residual stenosis) at all lesions attempted without the adverse events of myocardial infarction, same-admission bypass surgery, or death. There were 412 617 PCI procedures included in the analysis. Frequency of indications was as follows: Class I, 64%; Class IIa, 21%; Class IIb, 7%; and Class III, 8%. Clinical success declined across the indications classes (92.8%, 91.7%, 89%, and 85.5%, respectively; P<0.001), whereas adverse events increased.

In this large survey of contemporary PCI practice, most procedures were performed for Class I indications. A significant relationship between evidence-based indications recommended by the ACC/AHA Task Force and in-hospital outcomes was noted.

Prevention of fatal arrhythmias in high-risk subjects by fish oil

The long-chain n-3 fatty acids in fish have been demonstrated to have antiarrhythmic properties in experimental models and to prevent sudden cardiac death in a randomized trial of post-myocardial infarction patients. Therefore, we hypothesized that these n-3 fatty acids might prevent potentially fatal ventricular arrhythmias in high-risk patients.

Four hundred two patients with implanted cardioverter/defibrillators (ICDs) were randomly assigned to double-blind treatment with either a fish oil or an olive oil daily supplement for 12 months. The primary end point, time to first ICD event for ventricular tachycardia or fibrillation (VT or VF) confirmed by stored electrograms or death from any cause, was analyzed by intention to treat. Secondary analyses were performed for "probable" ventricular arrhythmias, "on-treatment" analyses for all subjects who had taken any of their oil supplements, and "on-treatment" analyses only of those subjects who were on treatment for at least 11 months. Compliance with double-blind treatment was similar in the 2 groups; however, the noncompliance rate was high (35% of all enrollees). In the primary analysis, assignment to treatment with the fish oil supplement showed a trend toward a prolonged time to the first ICD event (VT or VF) or of death from any cause (risk reduction of 28%; P=0.057). When therapies for probable episodes of VT or VF were included, the risk reduction became significant at 31%; P=0.033. For those who stayed on protocol for at least 11 months, the antiarrhythmic benefit of fish oil was improved for those with confirmed events (risk reduction of 38%; P=0.034).

Although significance was not achieved for the primary end point, this study provides evidence that for individuals at high risk of fatal ventricular arrhythmias, regular daily ingestion of fish oil fatty acids may significantly reduce potentially fatal ventricular arrhythmias.

Ghrelin improves endothelial function in patients with metabolic syndrome

Metabolic syndrome accelerates the atherosclerotic process, the earliest event of which is endothelial dysfunction. Ghrelin, a gastric peptide with cardiovascular actions, has been shown to inhibit proatherogenic changes in experimental models. The effect of ghrelin administration on endothelial function in patients with metabolic syndrome was investigated.

Endothelium-dependent and independent vasodilator responses to intra-arterial infusion of increasing doses of acetylcholine and sodium nitroprusside (SNP), respectively, were assessed by strain-gauge plethysmography before and after local administration of human ghrelin (200 ΅g/min). During saline, the vasodilator response to acetylcholine was significantly blunted (P = 0.008) in patients with metabolic syndrome (n = 12, 5 female) compared with controls (n = 12, 7 female), whereas the vasodilator response to SNP was not different between groups (P = 0.68). In patients with metabolic syndrome, basal plasma ghrelin was significantly lower than in controls (P = 0.02). In these patients, ghrelin infusion markedly increased intravascular concentrations of the peptide (P < 0.001) and resulted in a potentiation of the vasodilator response to acetylcholine (P = 0.001 versus saline) but not to SNP (P = 0.22). This effect was likely related to enhanced nitric oxide bioavailability because, in a group of patients with metabolic syndrome (n = 6, 2 female), ghrelin had no effect on the vasodilator response to acetylcholine (P = 0.78 versus saline) after nitric oxide inhibition by NG-monomethyl-L-arginine.

The findings in this study indicate that Ghrelin reverses endothelial dysfunction in patients with metabolic syndrome by increasing nitric oxide bioactivity, thereby suggesting that decreased circulating levels of the peptide, such as those found in metabolic syndrome patients, might play a role in the pathobiology of atherosclerosis.

Risk of high blood pressure among young men increases with the degree of immaturity at birth

Survivors of preterm birth constitute a new generation of young adults, but little is known about their long-term health. Swedish investigators studied the association between gestational age (GA) and risk of high blood pressure (HBP) in young Swedish men.

This population-based cohort study included 329 495 Swedish men born in 1973 to 1981 who were conscripted for military service in 1993 to 2001. Multivariate linear- and logistic-regression analyses were performed. Main outcome measures were systolic and diastolic BPs at conscription. Linear-regression analyses showed that systolic BP increased with decreasing GA (regression coefficient -0.31 mm Hg/wk, P<0.001). Systolic and diastolic BPs both increased with decreasing birth weight for GA, but the association with systolic BP was most evident (regression coefficient -0.67 mm Hg per SD score in birth weight for GA, P<0.001). Compared with men born at term (GA, 37 to 41 weeks), the adjusted odd ratios (95% confidence intervals [CIs]) for high systolic BP ( 140 mm Hg) were as follows: moderately preterm (33 to 36 weeks), 1.25 (1.19 to 1.30); very preterm (29 to 32 weeks), 1.48 (1.30 to 1.68); and extremely preterm (24 to 28 weeks), 1.93 (1.34 to 2.76). Being SGA was associated only with an increased risk of high systolic BP among men born at 33 weeks or later. The risk estimates for high diastolic BP (90 mm Hg) increased with decreasing GA, but the risk reached significance only among men born moderately preterm.

The study concluded that preterm birth, a common pregnancy complication, is a risk factor for HBP in young men. The risk of high systolic BP associated with birth weight for GA is modified by GA, suggesting that perinatal contributions to BP elevation later in life may be induced by different biological pathways.

Comparison of bare-metal stenting with minimally invasive bypass surgery for stenosis of the left anterior descending coronary artery a 5-year follow-up

Randomized trials comparing stenting with minimally invasive direct coronary artery bypass surgery in patients with isolated proximal left anterior descending lesions have shown a significantly higher reintervention rate for stenting and similar results for mortality and reinfarction at short-term follow-up. Long-term follow-up data are sparse.

Patients with isolated proximal left anterior descending stenosis were randomized to either surgery (n = 110) or bare-metal stenting (n = 110). At 5 years, follow-up data were obtained with respect to the primary end point of death, reinfarction, or repeated target vessel revascularization. Clinical symptoms were assessed by the Canadian Cardiovascular Society (CCS) classification. Follow-up information was completed for 216 patients (98.2%), and mean follow-up was 5.6 - 1.2 years. With respect to mortality (surgery, 12%; stenting, 10%; P = 0.54) and reinfarctions (surgery, 7%; stenting, 5%; P = 0.46), there were no differences between treatment strategies. The need for repeated target vessel revascularization was significantly higher after stenting (32%) compared with surgery (10%; P < 0.001). Clinical symptoms improved significantly in both treatment groups compared with baseline; however, there was a favorable trend for surgery (stenting: CCS, 2.6 - 0.9 to 0.5 - 0.8, P < 0.001; surgery: CCS, 2.6 - 0.9 to 0.3 - 0.6, P < 0.001; P=0.05, stenting versus surgery).

At the 5-year follow-up, minimally invasive bypass surgery and bare-metal stenting showed similar results for the end points of mortality and reinfarctions. However, the reintervention rate is higher after stenting, and the relief in clinical symptoms is slightly better after surgery.

Reverse remodeling of the left cardiac chambers after catheter ablation after 1 year in a series of patients with isolated atrial fibrillation

Isolated atrial fibrillation (AF) is associated with mild enlargement of the left atrium (LA) and left ventricular (LV) diastolic dysfunction. The impact of ablation of isolated AF on left chamber size and function is unclear, and whether diastolic dysfunction is the cause or the consequence of AF remains unknown. The objective of this prospective study was to evaluate the impact of sinus rhythm restoration by catheter ablation on LV diastolic dysfunction, LA morphology, and mechanical function.

Forty-eight patients with isolated AF were studied by serial echocardiographic studies at baseline and at 1-, 3-, 6-, 9-, and 12-month intervals after radiofrequency ablation. LA dimensions and mechanical function and LV systolic and diastolic functions were evaluated at each time interval. Diastolic function was assessed with conventional Doppler parameters and new indexes such as tissue Doppler imaging, mitral flow propagation velocity, and combined criteria. LV diastolic dysfunction was present in paroxysmal and chronic AF patients with a reduction of tissue Doppler imaging lateral early diastolic peak velocity in 37% (P<0.001) and 48% (P<0.01), respectively, compared with healthy control subjects.

At the end of the follow-up, LA area decreased significantly by 18% (P<0.001) in paroxysmal and 23% (P<0.05) in chronic AF patients. Diastolic function improved significantly with an increase in lateral early diastolic peak velocity of 29% (P<0.001) in paroxysmal AF and 46% (P<0.05) in chronic AF patients. A significant increase in LV ejection fraction was also noted for both groups: 7.7% and 18.8%, respectively.

This study demonstrates reverse morphological remodeling of the LA and improvement of LV diastolic and systolic functions after restoration of sinus rhythm by ablation for isolated AF. Because patients with isolated AF have none of the traditional causes of LV diastolic dysfunction, our findings suggest that AF may be partly the cause rather than the consequence of diastolic dysfunction.




 

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