Current Cardiology Reviews (v.8, #1)
Cyanotic Congenital Heart Disease The Coronary Arterial Circulation by Joseph K. Perloff (1-5).
Background: The coronary circulation in cyanotic congenital heart disease (CCHD) includes the extramural coronary arteries, basal coronary blood flow, flow reserve, the coronary microcirculation, and coronary atherogenesis. Methods: Coronary arteriograms were analyzed in 59 adults with CCHD. Dilated extramural coronaries were examined histologically in six patients. Basal coronary blood flow was determined with N-13 positron emission tomography in 14 patients and in 10 controls. Hyperemic flow was induced by intravenous dipyridamole pharmacologic stress. Immunostaining against SM alpha-actin permitted microcirculatory morphometric analysis. Non-fasting total cholesterols were retrieved in 279 patients divided into four groups: Group A---143 cyanotic unoperated, Group B---47 rendered acyanotic by reparative surgery, Group C---41 acyanotic unoperated, Group D---48 acyanotic before and after operation. Results: Extramural coronary arteries were mildly or moderately dilated to ectatic in 49/59 angiograms. Histologic examination disclosed loss of medial smooth muscle, increased medial collagen, and duplication of internal elastic lamina. Basal coronary flow was appreciably increased. Hyperemic flow was comparable to controls. Remodeling of the microcirculation was based upon coronary arteriolar length, volume and surface densities. Coronary atherosclerosis was absent in both the arteriograms and the necropsy specimens. Conclusions: Extramural coronary arteries in CCHD dilate in response to endothelial vasodilator substances supplemented by mural attenuation caused by medial abnormalities. Basal coronary flow was appreciably increased, but hyperemic flow was normal. Remodeling of the microcirculation was responsible for preservation of flow reserve. The coronaries were atheroma-free because of the salutory effects of hypocholesterolemia, hypoxemia, upregulated nitric oxide, low platelet counts, and hyperbilirubinrmia.
Synergy Between Direct Coronary Stenting Technique and Use of the Novel Thin Strut Cobalt Chromium Skylor™ Stent: the Mace in Follow Up Patients Treated with Skylor Stent [MILES Study] by Arturo Giordano, Michele Polimeno, Nicola Corcione, Luciano Fattore, Luigi Di Lorenzo, Giuseppe Biondi-Zoccai, Paolo Ferraro, Maria Fiammetta Romano (6-13).
BACKGROUND: Despite significant improvements in stent platform, currently available bare-metal stents (BMS) are still associated with restenosis. Thin-strut design cobalt-chromium alloys hold the promise of improving results of BMS, especially when implanted with direct technique. We performed an observational study to appraise outcomes of the novel Skylorand#8482; stent, stratifying outcomes according to stenting technique. METHODS and RESULTS: We included all consecutive patients undergoing coronary stenting with Skylorand#8482; at 2 centers between 2006 and 2009. The primary end-point was the long-term rate of major adverse cardiac events (MACE, i.e. death, myocardial infarction (MI), coronary artery bypass grafting (CABG) or target vessel revascularization (TVR)). As pre-specified analysis, we compared patients undergoing direct stenting versus those stent implantation following predilation. A total of 1020 patients were included (1292 Skylorand#8482; stents), with procedural success obtained in 99and#x25;. Comparing patients undergoing direct stenting (66and#x25;) versus pre-dilation (34and#x25;) at 16and#xB1;7 months of follow-up, MACE had occurred in, respectively, 8and#x25; versus 14and#x25; (p=0.001), with death in 1and#x25; versus 2= (p=0.380), MI in 1and#x25; versus 2and#x25; (p=0.032), CABG in 0.2and#x25; versus 2and#x25; (p=0.012), and TVR in 6and#x25; versus 9and#x25; [p=0.071]. Even at multivariable analysis with propensity adjustment, direct stenting was associated with significantly fewer MACE [hazard ratio 0.60 [0.38-0.93], p=0.024]. CONCLUSIONS: This observational study suggests the presence of a beneficial synergy between direct coronary stenting technique and use of the novel thin-strut cobalt-chromium Skylorand#8482; stent in real-world patients undergoing PCI.
On the Analysis of Fingertip Photoplethysmogram Signals by Mohamed Elgendi (14-25).
Photoplethysmography (PPG) is used to estimate the skin blood flow using infrared light. Researchers from different domains of science have become increasingly interested in PPG because of its advantages as non-invasive, inexpensive, and convenient diagnostic tool. Traditionally, it measures the oxygen saturation, blood pressure, cardiac output, and for assessing autonomic functions. Moreover, PPG is a promising technique for early screening of various atherosclerotic pathologies and could be helpful for regular GP-assessment but a full understanding of the diagnostic value of the different features is still lacking. Recent studies emphasise the potential information embedded in the PPG waveform signal and it deserves further attention for its possible applications beyond pulse oximetry and heart-rate calculation. Therefore, this overview discusses different types of artifact added to PPG signal, characteristic features of PPG waveform, and existing indexes to evaluate for diagnoses.
Myocardial Revascularization for the Elderly: Current Options, Role of Off-pump Coronary Artery Bypass Grafting and Outcomes by Shahzad G. Raja (26-36).
The increase in life expectancy has confronted cardiac surgery with a rapidly growing population of elderly patients requiring surgical myocardial revascularization. Recent advances in surgical and anesthetic techniques and improvements in postoperative care have made coronary artery bypass grafting an established therapeutic option for the treatment of coronary artery disease in this group of patients. However, conventional coronary artery bypass grafting on cardiopulmonary bypass is associated with significant risk and related morbidity and mortality in the elderly. In recent years off-pump coronary artery bypass grafting has emerged as a safe and less invasive strategy for surgical myocardial revascularization. Off-pump coronary artery bypass grafting by avoiding the deleterious effects of cardiopulmonary bypass can offer potential benefits to elderly patients requiring surgical myocardial revascularization. This review article provides an overview of the age-related cardiovascular changes, epidemiology of coronary artery disease in the elderly and focuses on outcomes of surgical myocardial revascularization with special emphasis on the impact of off-pump coronary artery bypass surgery in the elderly.
Evidence-Based Percutaneous Closure of the Left Atrial Appendage in Patients with Atrial Fibrillation by Silvio Leal, Raul Moreno, Manuel de Sousa Almeida, Jose Aniceto Silva, Jose L. Lopez- Sendon (37-42).
Atrial fibrillation is the most common cardiac arrhythmia, and its prevalence is increasing. Cardioembolic stroke, most of the times secondary to thrombus formation in the left atrial appendage, is its most feared and life threatening consequence. Oral anticoagulation with vitamin-K-antagonists is currently the most used prophylaxis for stroke in patients with atrial fibrillation; unfortunately, its benefits are limited by a narrow therapeutic window and an increased risk for bleeding, making it often undesired. Percutaneous occlusion of the left atrial appendage is a novel alternative strategy for cardioembolic stroke prophylaxis in patients with atrial fibrillation at a high risk of stroke but with contraindication for long-term oral anticoagulation therapy. At present, several devices have been developed specifically for percutaneous occlusion of the left atrial appendage. Current results show good feasibility and efficacy for these devices, with a high rate of successful implantation, although also associated with the inherent potential periprocedural complications. This work reviews the current state of the art of percutaneous left atrial appendage closure for stroke prophylaxis in patients with atrial fibrillation.
Tissue Doppler Imaging in Coronary Artery Diseases and Heart Failure by Michele Correale, Antonio Totaro, Riccardo Ieva, Armando Ferraretti, Francesco Musaico, Matteo Di Biase (43-53).
Recent studies have explored the prognostic role of TDI-derived parameters in major cardiac diseases, such as coronary artery disease (CAD) and heart failure (HF). In these conditions, myocardial mitral annular systolic (Sand#x2019;) and early diastolic (Eand#x2019;) velocities have been shown to predict mortality or cardiovascular events. In heart failure non invasive assessment of LV diastolic pressure by transmitral to mitral annular early diastolic velocity ratio (E/Eand#x2019;) is a strong prognosticator, especially when E/Eand#x2019; is > or =15. Moreover, other parameters derived by TDI, as cardiac time intervals and Myocardial Performance Index, might play a role in the prognostic stratification in CAD and HF. Recently, a threedimensional (3-D) TDI imaging modality, triplane TDI, has become available, and this allows calculation of 3-Dvolumes and LV ejection fraction. We present a brief update of TDI.
Acute Cardioembolic Cerebral Infarction: Answers to Clinical Questions by Adria Arboix, Josefina Alio (54-67).
Cardioembolic cerebral infarction (CI) is the most severe subtype of ischaemic stroke but some clinical aspects of this condition are still unclear. This article provides the reader with an overview and up-date of relevant aspects related to clinical features, specific cardiac disorders and prognosis of CI. CI accounts for 14-30and#x25; of ischemic strokes; patients with CI are prone to early and long-term stroke recurrence, although recurrences may be preventable by appropriate treatment during the acute phase and strict control at follow-up. Certain clinical features are suggestive of CI, including sudden onset to maximal deficit, decreased level of consciousness at onset, Wernickeand#x2019;s aphasia or global aphasia without hemiparesis, a Valsalva manoeuvre at the time of stroke onset, and co-occurrence of cerebral and systemic emboli. Lacunar clinical presentations, a lacunar infarct and especially multiple lacunar infarcts, make cardioembolic origin unlikely. The most common disorders associated with a high risk of cardioembolism include atrial fibrillation, recent myocardial infarction, mechanical prosthetic valve, dilated myocardiopathy and mitral rheumatic stenosis. Patent foramen ovale and complex atheromatosis of the aortic arch are potentially emerging sources of cardioembolic infarction. Mitral annular calcification can be a marker of complex aortic atheroma in stroke patients of unkown etiology. Transthoracic and transesophageal echocardiogram can disclose structural heart diseases. Paroxysmal atrial dysrhyhtmia can be detected by Holter monitoring. Magnetic resonance imaging, transcranial Doppler, and electrophysiological studies are useful to document the source of cardioembolism. In-hospital mortality in cardioembolic stroke (27.3and#x25;, in our series) is the highest as compared with other subtypes of cerebral infarction. Secondary prevention with anticoagulants should be started immediately if possible in patients at high risk for recurrent cardioembolic stroke in which contraindications, such as falls, poor compliance, uncontrolled epilepsy or gastrointestinal bleeding are absent. Dabigatran has been shown to be non-inferior to warfarin in the prevention of stroke or systemic embolism. All significant structural defects, such as atrial septal defects, vegetations on valve or severe aortic disease should be treated. Aspirin is recommended in stroke patients with a patent foramen ovale and indications of closure should be individualized. CI is an important topic in the frontier between cardiology and vascular neurology, occurs frequently in daily practice, has a high impact for patients, and health care systems and merits an update review of current clinical issues, advances and controversies.
Circulatory Syndrome: An Evolution of the Metabolic Syndrome Concept! by Ali Reza Khoshdel, Shane L.Carney, Alastair Gillies (68-76).
The metabolic syndrome has been a useful, though controversial construct in clinical practice as well as a valuable model in order to understand the interactions of diverse cardiovascular risk factors. However the increasing importance of the circulatory system in particular the endothelium, in both connecting and controlling organ function has underlined the limitations of the metabolic syndrome definition. The proposed and#x201C;Circulatory Syndromeand#x201D; is an attempt to refine the metabolic syndrome concept by the addition of recently documented markers of cardiovascular disease including renal impairment, microalbuminuria, arterial stiffness, ventricular dysfunction and anaemia to more classic factors including hypertension, dyslipidemia and abnormal glucose metabolism; all of which easily measured in clinical practice. These markers interact with each other as well as with other factors such as aging, obesity, physical inactivity, diet and smoking. The final common pathways of inflammation, oxidative stress and hypercoagulability thereby lead to endothelial damage and eventually cardiovascular disease. Nevertheless, the Circulatory (MARC) Syndrome, like its predecessor the metabolic syndrome, is only a small step toward an understanding of these complex and as yet poorly understood markers of disease.
Beta Blocker Use After Acute Myocardial Infarction in the Patient with Normal Systolic Function: When is it “Ok” to Discontinue? by Anna Kezerashvili, Kevin Marzo, Joshua De Leon (77-84).
Beta-Blockers [BB] have been used extensively in the last 40 years after acute myocardial infarction [AMI] as part of therapy and in secondary prevention. The evidence for and#x201C;routineand#x201D; therapy with beta-blocker use post AMI rests largely on results of trials conducted over 25 years ago. However, there remains no clear recommendation regarding the appropriate duration of treatment with BBs in post AMI patients with normal left ventricular ejection fraction [LVEF] who are not experiencing angina, or who require BB for hypertension or dysrhythmia. Based on the latest ACC/AHA guidelines, BBs are recommended for early use in the setting of AMI, except in patients who are at low risk and then indefinitely as secondary prevention after AMI. This recommendation was downgraded to class IIa in low risk patients and the updated 2007 ACC/AHA guidelines suggest that the rationale for BB for secondary prevention is from limited data derived from extrapolations of chronic angina and heart failure trials. In this review, we examine the key trials that have shaped the current guidelines and recommendations. In addition, we attempt to answer the question of the duration of BB use in patients with preserved LVEF after acute MI, as well as which subgroups of patients benefits most from post AMI use of beta blockers.