Recent updates on therapeutic targeting of lipoprotein(a) with RNA interference.

PURPOSE OF REVIEW: RNA interference (RNAi)-based therapies that target specific gene products have impacted clinical medicine with 16 FDA approved drugs. RNAi therapy focused on reducing plasma lipoprotein(a) [Lp(a)] levels are under evaluation. RECENT FINDINGS: RNAi-based therapies have made significant progress over the past 2 decades and currently consist of antisense oligonucleotides (ASO) and small interfering RNA (siRNA). Chemical modification of the RNA backbone and conjugation of siRNA enables efficient gene silencing in hepatocytes allowing development of effective cholesterol lowering therapies. Multiple lines of evidence suggest a causative role for Lp(a) in atherosclerotic cardiovascular disease, and recent analyses indicate that Lp(a) is more atherogenic than low density lipoprotein- cholesterol (LDL-C). These findings have led to the 'Lp(a) hypothesis' that lowering Lp(a) may significantly improve cardiovascular outcomes. Four RNAi-based drugs have completed early phase clinical trials demonstrating >80% reduction in plasma Lp(a) levels. Phase 3 clinical trials examining clinical outcomes with these agents are currently underway. SUMMARY: Currently, four RNAi-based drugs have been shown to be effective in significantly lowering plasma Lp(a) levels. Clinical outcome data from phase 3 trials will evaluate the Lp(a) hypothesis.

Role of Cyp2c19 Genotype-Guided Antiplatelet Therapy After Percutaneous Coronary Intervention.

PURPOSE OF REVIEW: Identification of a reliable discriminatory test to accurately stratify patient responses to antiplatelet therapy following coronary revascularization has become increasingly desirable to optimize therapeutic efficacy and safety. RECENT FINDINGS: The expansion of platelet function testing to include genotype assessment has been an evolutionary journey, initially fraught with confounding results. However, more recent and rigorous data analysis suggests that genotype testing- guided, tailored antiplatelet therapy may hold promise in optimizing treatment of patients after coronary intervention. Current evidence increasingly supports the use of genotype guided CYP2C19 testing to better match the post coronary intervention patient with the most efficacious and least risky antiplatelet inhibitor. The risk stratification of poor, intermediate, and good metabolizers of these drugs with such testing promises to yield clinical dividends in terms of morbidity, mortality and cost control, in this growing patient population.

Sleep apnea and cardiovascular risk.

PURPOSE OF REVIEW: Obstructive sleep apnea (OSA) is associated with several cardiovascular risk predictors that have only recently begun to be studied in detail. The strong association between OSA and hypertension, coronary artery disease, congestive heart failure, and sudden cardiac death underscores its significant impact on cardiovascular health. This brief review considers the links between OSA and cardiovascular risk. RECENT FINDINGS: OSA is an important contributor to endothelial dysfunction and damage, while repetitive hypoxia and hypercarbia contribute to autonomic dysfunction and sympathetic stimulation. In turn, these derangements have deleterious hematologic effects, including hypercoagulability and abnormal platelet aggregability, which are important in the pathogenesis of atherothrombotic disease. SUMMARY: The varied deleterious effects of OSA on cardiovascular health stem from a unique 'perfect storm' of hypoxic oxidative stress, autonomic dysregulation, endothelial damage, and inflammation occurring at the microvascular level. Further research may disentangle these multiple etiologic threads and provide a better understanding of the underlying pathophysiological relationship between OSA and cardiovascular disease.

REAFFIRMING THE CORE VALUES OF ACADEMIC CARDIOLOGY.

Academic medical centers are rapidly evolving into academic health systems with expanding clinical activity. These changes coupled with financial pressures due to decreased clinical reimbursements and failure of the NHLBI budget to keep pace with inflation are challenging the ability to succeed in all our missions. New governance structures and financial models may be necessary to success in our research and educational missions.

Treatment of Hypertension Among Non-Cardiac Hospitalized Patients.

PURPOSE OF REVIEW: This review provides a contemporary perspective and approach for the treatment of hypertension (HTN) among patients hospitalized for non-cardiac reasons. RECENT FINDINGS: Elevated blood pressure (BP) is a common dilemma encountered by physicians, but guidelines are lacking to assist providers in managing hospitalized patients with elevated BP. Inpatient HTN is common, and management remains challenging given the paucity of data and misperceptions among training and practicing physicians. The outcomes associated with intensifying BP treatment during hospitalization can be harmful, with little to no long-term benefits. Data also suggests that medication intensification at discharge is not associated with improved outpatient BP control. Routine inpatient HTN control in the absence of end-organ damage has not shown to be helpful and may have deleterious effects. Since routine use of intravenous antihypertensives in hospitalized non-cardiac patients has been shown to prolong inpatient stay without benefits, their routine use should be avoided for inpatient HTN control. Future large-scale trials measuring clinical outcomes during prolonged follow-up may help to identify specific circumstances where inpatient HTN control may be beneficial.

Acute Toxicity from Topical Cocaine for Epistaxis: Treatment with Labetalol.

BACKGROUND: Topical cocaine is sometimes used for the treatment of epistaxis, as it has both potent anesthetic and vasoconstrictive properties. Cocaine has unpredictable cardiovascular effects, such as sudden hypertension, tachycardia, coronary arterial vasoconstriction, and dysrhythmia. CASE REPORT: We report a case of acute iatrogenic cardiovascular toxicity from the use of topical cocaine in a 56-year-old man presenting to the Emergency Department with profound epistaxis. To prepare for cauterization and nasal packing, the patient received 4% topical cocaine-soaked nasal pledgets. He became hypertensive, tachypneic, tachycardic, and dysphoric immediately after administration. To directly counter these adverse hyperadrenergic effects, the patient was given 10 mg intravenous labetalol, a mixed ß- and α-blocker. This instantly normalized his vital signs and adverse subjective effects. His epistaxis was successfully treated, and he was discharged 1 h later. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: We believe that emergency physicians should be aware of the unpredictable acute cardiovascular toxicity of topical cocaine. Labetalol represents an effective first-line treatment, which, unlike benzodiazepines, directly counters the pharmacologic effects of cocaine and has no respiratory or sedative side effects. Labetalol, with its mixed ß/α-blocking properties, also mitigates the potential for "unopposed α-stimulation."

Transformative Impact of Proteomics on Cardiovascular Health and Disease: A Scientific Statement From the American Heart Association.

The year 2014 marked the 20th anniversary of the coining of the term proteomics. The purpose of this scientific statement is to summarize advances over this period that have catalyzed our capacity to address the experimental, translational, and clinical implications of proteomics as applied to cardiovascular health and disease and to evaluate the current status of the field. Key successes that have energized the field are delineated; opportunities for proteomics to drive basic science research, facilitate clinical translation, and establish diagnostic and therapeutic healthcare algorithms are discussed; and challenges that remain to be solved before proteomic technologies can be readily translated from scientific discoveries to meaningful advances in cardiovascular care are addressed. Proteomics is the result of disruptive technologies, namely, mass spectrometry and database searching, which drove protein analysis from 1 protein at a time to protein mixture analyses that enable large-scale analysis of proteins and facilitate paradigm shifts in biological concepts that address important clinical questions. Over the past 20 years, the field of proteomics has matured, yet it is still developing rapidly. The scope of this statement will extend beyond the reaches of a typical review article and offer guidance on the use of next-generation proteomics for future scientific discovery in the basic research laboratory and clinical settings.

Inaccuracy of estimated resting oxygen uptake in the clinical setting.

BACKGROUND: The Fick principle (cardiac output = oxygen uptake ( O2)/systemic arterio-venous oxygen difference) is used to determine cardiac output in numerous clinical situations. However, estimated rather than measured O2 is commonly used because of complexities of the measurement, though the accuracy of estimation remains uncertain in contemporary clinical practice. METHODS AND RESULTS: From 1996 to 2005, resting O2 was measured via the Douglas bag technique in adult patients undergoing right heart catheterization. Resting O2 was estimated by each of 3 published formulae. Agreement between measured and estimated O2 was assessed overall, and across strata of body mass index, sex, and age. The study included 535 patients, with mean age 55 yrs, mean body mass index 28.4 kg/m2; 53% women; 64% non-white. Mean (±standard deviation) measured O2 was 241 ± 57 ml/min. Measured O2 differed significantly from values derived from all 3 formulae, with median (interquartile range) absolute differences of 28.4 (13.1, 50.2) ml/min, 37.7 (19.4, 63.3) ml/min, and 31.7 (14.4, 54.5) ml/min, for the formulae of Dehmer, LaFarge, and Bergstra, respectively (P<0.0001 for each). The measured and estimated values differed by >25% in 17% to 25% of patients depending on the formula used. Median absolute differences were greater in severely obese patients (body mass index > 40 kg/m2), but were not affected by sex or age. CONCLUSIONS: Estimates of resting O2 derived from conventional formulae are inaccurate, especially in severely obese individuals. When accurate hemodynamic assessment is important for clinical decision-making, O2 should be directly measured.

Integrative computational and experimental approaches to establish a post-myocardial infarction knowledge map.

Vast research efforts have been devoted to providing clinical diagnostic markers of myocardial infarction (MI), leading to over one million abstracts associated with "MI" and "Cardiovascular Diseases" in PubMed. Accumulation of the research results imposed a challenge to integrate and interpret these results. To address this problem and better understand how the left ventricle (LV) remodels post-MI at both the molecular and cellular levels, we propose here an integrative framework that couples computational methods and experimental data. We selected an initial set of MI-related proteins from published human studies and constructed an MI-specific protein-protein-interaction network (MIPIN). Structural and functional analysis of the MIPIN showed that the post-MI LV exhibited increased representation of proteins involved in transcriptional activity, inflammatory response, and extracellular matrix (ECM) remodeling. Known plasma or serum expression changes of the MIPIN proteins in patients with MI were acquired by data mining of the PubMed and UniProt knowledgebase, and served as a training set to predict unlabeled MIPIN protein changes post-MI. The predictions were validated with published results in PubMed, suggesting prognosticative capability of the MIPIN. Further, we established the first knowledge map related to the post-MI response, providing a major step towards enhancing our understanding of molecular interactions specific to MI and linking the molecular interaction, cellular responses, and biological processes to quantify LV remodeling.

Myofibroblasts and the extracellular matrix network in post-myocardial infarction cardiac remodeling.

The cardiac extracellular matrix (ECM) fills the space between cells, supports tissue organization, and transduces mechanical, chemical, and biological signals to regulate homeostasis of the left ventricle (LV). Following myocardial infarction (MI), a multitude of ECM proteins are synthesized to replace myocyte loss and form a reparative scar. Activated fibroblasts (myofibroblasts) are the primary source of ECM proteins, thus playing a key role in cardiac repair. A balanced turnover of ECM through regulation of synthesis by myofibroblasts and degradation by matrix metalloproteinases (MMPs) is critical for proper scar formation. In this review, we summarize the current literature on the roles of myofibroblasts, MMPs, and ECM proteins in MI-induced LV remodeling. In addition, we discuss future research directions that are needed to further elucidate the molecular mechanisms of ECM actions to optimize cardiac repair.

The tell-tale heart: molecular and cellular responses to childhood anthracycline exposure.

Since the modern era of cancer chemotherapy that began in the mid-1940s, survival rates for children afflicted with cancer have steadily improved from 10% to current rates that approach 80% (60). Unfortunately, many long-term survivors of pediatric cancer develop chemotherapy-related health effects; 25% are afflicted with a severe or life-threatening medical condition, with cardiovascular disease being a primary risk (96). Childhood cancer survivors have markedly elevated incidences of stroke, congestive heart failure (CHF), coronary artery disease, and valvular disease (96). Their cardiac mortality is 8.2 times higher than expected (93). Anthracyclines are a key component of most curative chemotherapeutic regimens used in pediatric cancer, and approximately half of all childhood cancer patients are exposed to them (78). Numerous epidemiologic and observational studies have linked childhood anthracycline exposure to an increased risk of developing cardiomyopathy and CHF, often decades after treatment. The acute toxic effects of anthracyclines on cardiomyocytes are well described; however, myocardial tissue is comprised of additional resident cell types, and events occurring in the cardiomyocyte do not fully explain the pathological processes leading to late cardiomyopathy and CHF. This review will summarize the current literature regarding the cellular and molecular responses to anthracyclines, with an important emphasis on nonmyocyte cardiac cell types as well as those that mediate the myocardial injury response.

Cardiac assessment in pediatric mice: strain analysis as a diagnostic measurement.

Echocardiography is a robust tool for assessing cardiac function in both humans and laboratory animals. Conventional echocardiographic measurements, including chamber dimensions, wall thickness, and ejection fraction are routinely obtained to assess cardiac function in mice. Recently, myocardial strain and strain rate measurements have been added to functional assessments to provide additional details on regional abnormalities that are not evident using conventional measurements. To date, all studies of strain and strain rate in mice or rats have involved adult animals. This study serves to outline methods for acquiring echocardiographic images in pediatric mice and to provide myocardial strain and strain rate values for healthy C57BL/6J mice between 3 and 11 weeks old. Between weeks 3 and 11, left ventricular radial strain ranged from 32 to 43% and longitudinal strain ranged from -15 to -19%, with analysis over time showing no significant changes with aging (radial strain, P = 0.192 and longitudinal strain, P = 0.264; n = 4 for each time point evaluated). In conclusion, myocardial strain analysis in pediatric mice is technically feasible and has potential application in studying the pathophysiology of pediatric cardiovascular disease.

Sexual activity and ischemic heart disease.

Human sexuality is an important aspect of health and quality of life. Many patients with ischemic heart disease - and their partners - are concerned that sexual activity could exacerbate their cardiac condition, possibly causing myocardial infarction or cardiac death. Patients with ischemic heart disease who wish to initiate or resume sexual activity should be evaluated with a thorough medical history and physical examination. Sexual activity is reasonable for individuals with no or mild angina and those who can exercise ≥ 3-5 METS without angina, excessive dyspnea, or ischemic ST segment changes. For the patient who is considered not be at low cardiovascular (CV) risk or in whom the CV risk is unknown, an exercise stress test is reasonable in order to determine his or her exercise capacity and to ascertain if symptoms or ischemia may occur. Regular exercise and cardiac rehabilitation can be effective in reducing the risk of CV complications associated with sexual activity for the patient with ischemic heart disease.

Effect of percutaneous coronary intervention on quality of life: a consensus statement from the Society for Cardiovascular Angiography and Interventions.

Percutaneous coronary intervention (PCI) decreases ischemic complications of acute coronary syndromes. The benefits of PCI in stable ischemic heart disease (SIHD) depend on its effect on quality of life (QoL), including angina, physical activity, and emotional well-being. PCI decreases angina and the need for anti-anginal medications, and increases exercise capacity and QoL, compared with baseline status and compared with medical therapy without PCI. These benefits are greater when QOL is markedly impaired by severe angina before the procedure. When considering treatment options for symptomatic SIHD, physicians should consider and provide objective data regarding QoL effects for each treatment strategy. QoL outcomes should be considered in clinical trials, appropriate use criteria, practice guidelines, and reimbursement policies for PCI.

Treatment of acute coronary syndrome: part 2: ST-segment elevation myocardial infarction.

OBJECTIVE: Familiarize clinicians with recent information regarding the diagnosis and treatment of ST-segment elevation myocardial infarction. DATA SOURCES: PubMed search and review of relevant medical literature. SUMMARY: Definition, pathophysiology, clinical presentation, diagnosis, and treatment of ST-segment elevation myocardial infarction are reviewed. CONCLUSIONS: Patients with ST-segment elevation myocardial infarction benefit from prompt reperfusion therapy. Adjunctive antianginal, antiplatelet, antithrombotic, beta blocker, angiotensin-converting enzyme inhibitor, and statin agents minimize ongoing cardiac ischemia, prevent thrombus propagation, and reduce the risk of recurrent cardiovascular events.