The clinical and angiographic spectrum of isolated,nondominant, left circumflex coronary disease

Sixteen of 994 patients with arteriosclerotic heart disease and dominant right coronary arteries had isolated left circumflex obstruction. Of these, 6 patients had significant (75%) narrowing in the main circumflex, 10 in 1 of the marginal branches and 1 in the atrioventricular groove branch. Angina was mild in 5, moderate to severe in 8, and unstable in 1. Four patients had prior myocardial infarction (MI), and 1 had a recent MI complicated by posterior papillary muscle rupture. The EKG was normal in 5, showed an MI in 2, LBBB in 1, RBBB in 2, ST-T wave changes in 3, LVH in 2, and atrial fibrillation in 2. Left ventricular angiography performed in the right anterior oblique projection revealed normal contraction in 9 patients, apical hypokinesis in 4, posterobasal hypokinesis in 1, and diffuse hypokinesis in 2. The left ventricular end diastolic pressure was normal in 11 patients and elevated in 5. The cardiac index was normal in 12 patients and reduced in 2. Isolated, nondominant, left circumflex coronary disease is an uncommon entity in symptomatic patients. However, when present, it may produce significant clinical and hemodynamic impairment.     

Impact of Changing Definitions for Myocardial Infarction: A Report from the AMIS Registry

Background

To assess the impact of the new definitions of myocardial infarction, we retrospectively analyzed 9190 patients from 63 hospitals with reported peak troponin values included between 2001 and 2007 in the Swiss AMIS (Acute Myocardial Infarction in Switzerland) Plus registry.

Methods

Patients were classified as belonging to the “classic” myocardial infarction group (peak total CK or CK-MB above the upper limit of normal, or troponin T [TnT] >0.1 μg/L or troponin I [TnI] >0.1-0.8 μg/L [depending on the assay]) or “new” myocardial infarction group (TnT >0.01 μg/L or TnI >0.01-0.07 μg/L).

Results

There were 489 patients in the “new” group who were similar to the 8701 “classic” patients in terms of age, sex, and prevalence of both diabetes and renal failure, but more frequently had a history of prior coronary artery disease, hypertension, and hyperlipidemia. At admission, they less frequently had ST elevation on their electrocardiogram, were more frequently in Killip class I, and received less primary percutaneous coronary intervention. Hospital mortality was 3.5% in the “new” and 6.7% in the “classic” myocardial infarction group (P = .004). In a subset of patients with a longer follow-up, mortality at 3 and 12 months was 1% and 5.6%, respectively, for “new” and 1.6% and 4%, respectively, for “classic” myocardial infarction (NS).

Conclusions

Patients with minimal elevation of serum troponin have smaller infarctions, less aggressive treatment, fewer early complications, and a better early prognosis than patients with higher serum biomarker levels. After discharge, however, their prognosis currently appears no different from that of patients with a “classic” myocardial infarction event.     

Cardiac Pain, Sympathetic Afferents, and Life-Threatening Arrhythmias

Cardiac Pain, Sympathetic Afferents, and Life-Threatening Arrhythmias. Myocardial ischemia activates receptors of sympathetic and vagal afferent fibers. Although both afferent pathways are excited, this article primarily focuses on the sympathetic pathways. Increased sympathetic afferent activity to cells of the spinal cord can lead to cardiac pain and reflex sympathetic hyperactivity that can be quite arrhythmogenic. Complicating factors that affect the relationship arises from activation of vagal afferent fibers. Sympathetic afferent fibers in the ventricle appear to be composed of mechanosensitive and chemosensitive receptors. Sympathetic afferent fibers excite cells of origin of the spinothalamic tract, the classical pain pathway that transmits information about noxious somatic and visceral episodes to areas of the brain involved with pain perception. Activation of selected brainstem nuclei, the vagus, and the dorsal columns can suppress afferent information from the heart that excites spinothalamic tract cells. Excitation of sympathetic afferent fibers initiates a series of cardiovascular reflexes, some of which may affect cardiac electrical stability significantly. Increased arrhythmogenesis can be reduced when C₈-T₅ dorsal roots are transected. Stimulation of cardiac nerves that involve the left stellate ganglion can produce life-threatening arrhythmias, particularly if combined with myocardial ischemia or infarction. Through reflex mechanisms, activation of sympathetic afferent fibers can suppress activity of vagal efferent fibers. If prevention of cardiac pain through reduced firing or inhibition of cells in the spinothalamic tract reduces afferent sympathetic activity that occurs during acute myocardial ischemia, it would be logical to surmise that another significant benefit would follow, namely reduced risk for malignant arrhythmias.     

Percutaneous replacement of pulmonary valve using the Edwards-Cribier percutaneous heart valve: first report in a human patient.

We report on the use of the Edwards-Cribier percutaneous heart valve (PHV) in a stenotic right ventricle to pulmonary artery homograft in a 16-year old patient who underwent the Ross operation. Initially, the homograft was stented and at the same procedure, the PHV was deployed inside it. This is the first human case of the application of this valve in the pulmonary valve position.     

Feasibility of the PCI through 6F diagnostic catheters.

BACKGROUND: The choice of guiding catheter for optimal back-up support is critical in order to achieve a successful PCI. Diagnostic 6 French (F) catheters have an internal lumen diameter as large as 5F guiding catheters. The aim of this study was to demonstrate for the first time the feasibility of performing PCI with Cordis 6F diagnostic catheters in selected coronary lesions. METHODS: 32 coronary stents were implanted using 6F diagnostic catheters in 27 eligible patients at the Montreal Heart Institute. The inclusion criteria were TIMI angiographic score < B2 in native coronary arteries or in coronary artery bypass grafts. Bifurcations and left main disease were not included. RESULTS: Eighty-five percent of the patients underwent PCI for acute coronary syndromes (ACS). PCI was performed in 5 lesions (19%) of the left coronary circulation; in 21 lesions (78%) of the right coronary artery and in one lesion (4%) of the 1st obtuse marginal branch of the circumflex artery, through a left mammary artery bypass. Only stents suitable for 5F guiding catheters were used. The largest stent was 4.0 mm in diameter and 32 mm in length. Direct stenting was performed in 75% of patients. The angiographic success for PCI of target lesions was 100%, without clinical or angiographic complications. CONCLUSIONS: In selected cases, diagnostic 6F catheters can be used for PCI with 5F compatible balloons and stents. PCI via a diagnostic catheter may provide even better back-up support and allows for significant resources and time savings, especially in patients with ACS.     

Spontaneous coronary artery dissection and associated CT coronary angiographic findings: a case report and review

We report a case of an acute coronary syndrome in a 21-year-old male with invasive coronary angiography and computed tomography (CT) coronary angiography showing a spontaneous dissection of the left anterior descending artery. To our knowledge the CT coronary angiographic appearance of spontaneous coronary artery dissection has been reported only once before. We describe the role CT coronary angiography may have in the evaluation of coronary dissection as well as potential treatment options.     

Pilot Results of the Early Detection by Ultrasound of Carotid Artery Intima-Media Thickness Evaluation (EDUCATE) study

BACKGROUND: Limitations of current models for risk stratification are known. Noninvasive imaging is being advocated as an adjunct to improve risk prediction; however, studies documenting outcomes are rare. Therefore, we aimed to evaluate the negative and positive predictive values of carotid atherosclerosis for future cardiovascular events. METHODS: The Early Detection by Ultrasound of Carotid Artery intima media Thickness Evaluation (EDUCATE) study prospectively enrolled 253 consecutive young to middle-aged adults undergoing elective coronary angiography. Bilateral carotid ultrasound and lipid profiles were performed. Carotid atherosclerosis was defined as intima media thickness >/=1.0 mm in the main body, or focal plaque within the body, bulb, or proximal branch. Future events included major (death, myocardial infarction, stroke) and minor (revascularization and new onset heart failure). RESULTS: Of the enrolled patients 236 completed all tests; mean age was 51 +/- 8 years; 58% women. Sensitivity, specificity, and negative predictive values for carotid atherosclerosis in predicting severe coronary artery disease were 72%, 49% and 79%, with an odds ratio (OR) of 2.2 (95% confidence interval [CI] 1.2-4.0). Of patients suffering major events, 90% had carotid atherosclerosis. Only 1 of 95 without carotid atherosclerosis experienced a major event. Kaplan-Meier analysis revealed differences in event-free survival in favor of subjects without carotid atherosclerosis for major (P = .051) and any event (P = .015). Cox analysis revealed a hazard ratio (HR) of 2.7 (95% CI 1.2-6.2; P = .020) for predicting future events. The relationship remained significant after adjusting for traditional risk factors (HR 2.5, 95% CI 1.1-5.9; P = .034). CONCLUSIONS: Carotid atherosclerosis is associated with severe coronary artery disease and future events. Negative carotid ultrasound is associated with excellent prognosis.     

Stunning of the myocardium: An update

Summary When severely ischemic myocardium is reperfused, prolonged myocardial dysfunction—a phenomenon named myocardial stunning—frequently occurs. Stunning also occurs in a variety of other situations. These include myocardium located adjacent to infarcted tissue, transient increase in myocardial O₂ demands in the presence of incomplete coronary obstruction, during both systole and diastole, in isolated perfused hearts rendered ischemir or anoxic, and in a variety of clinical situations, such as following ischemic arrest in cardiac surgery, thrombolytic reperfusion, and after episodes of severe ischemia in Prinzmetal's angina or unstable angina. Although the fundamental mechanism (s) responsible for myocardial stunning has not been elucidated, in experimental preparations calcium antagonists, free-radical scavengers, and neutrophil depletion have each been found to be helpful in minimizing it.     

Changes of diastolic function induced by cigarette smoking: an echocardiographic study in patients with coronary artery disease.

In 28 chronic smokers (11 women, 17 men, 53 +/- 10 years old) with coronary artery disease (greater than 75% stenosis), left ventricular (LV) relaxation and filling behavior was assessed before and after inhalation of 0.9 mg nicotine (1 cigarette) by echocardiography. The following acute nicotine-mediated changes were noted (one-sided Wilcoxon test): heart rate increased from 67 to 81 beats/min (p greater than .001); the early diastolic flow (E wave) integral decreased from 49 to 39 mm (p less than .001); the late diastolic flow integral (A wave) increased from 36 to 41 mm (p less than .01). Consecutively, the ratio between E and A wave flow integrals decreased from 1.4 to 0.9 (p less than .001); the atrial contribution to LV filling rose from 42 to 53% (p less than .001); and the isovolumetric relaxation period increased from 89 to 122 ms (p less than .001). In cigarette smokers with coronary artery disease acute administration of nicotine hence causes a shift of mitral blood flow from early (E wave) to late (A wave) diastole and a prolongation of the isovolumetric relaxation time. Thus, cigarette smoking significantly affects LV diastolic function independently of its role as a risk factor for coronary atherosclerosis.