The effect of infectious diseases is profound, and their morbidity and mortality have only escalated in recent years. Between 1980 and 1992, mortality in the United States as a result of infectious diseases increased 58%, age-adjusted mortality increased 39%, and mortality in men exceeded that in women by almost five times. The leading causes of infectious death in 1992 were respiratory tract infections, HIV/AIDS, and septicemia, with attributed mortality per 100,000 being 30.3, 13.2, and 7.7, respectively. During the same 12-year interval, mortality from heart infections increased slightly from 1.1 to 1.5 per 100,000 and dropped from the fourth to the fifth leading cause of infectious death.1

The increase in infectious disease mortality is alarming. Despite the advent of antimicrobial therapies in the 1940s, infectious diseases continue to emerge and reemerge, especially in light of growing resistance to antibiotics. Antibiotic therapy has decreased the mortality of infectious cardiovascular diseases from nearly 100% in untreated cases. Current mortality rates depend on the location and extent of the cardiovascular infection, the type of organism and its sensitivity to antibiotics, the presence of prosthetic material, and patient age. Most patients with a cardiovascular infection survive, but the consequences can be many. When there is progressive damage to a valve, cardiac failure may ensue and valve replacement is necessary; cardiac failure, however, may not be completely reversed postoperatively. Emboli can be large and disabling and may result in renal dysfunction or failure, an acute stroke or meningitis, or splenic, coronary, or pulmonary infarction. Septic abscesses may develop in various organs; when they occur in the heart, surgery is usually necessary. Disease specific to the myocardium may result in chronic cardiomyopathy. Infectious disease of the pericardium may lead to chronic pericardial constriction. Even when an infection is thought to be completely treated, relapse or recurrence has been known to occur.

This issue of The Journal of Cardiovascular Nursing (13:2) highlights those elements that affect the causes and cures of cardiovascular diseases. The infecting pathogens are old and new, well-known and more obscure. Their eradication by antibiotics is usually successful, but constantly changing pathogen sensitivities require prudent antibiotic selection, specificity, and controlled use. When an antibiotic is inappropriately used or overused, a pathogen may develop resistance. There are many reasons why a person develops a cardiovascular infection, but being immunocompromised is a high risk factor. There are all kinds of acute and chronic cardiac and vascular infections, and the medical or surgical treatment possibilities depend on a variety of factors. One example of a cardiovascular infection with an associated high mortality rate is prosthetic valve endocarditis that requires surgical valve replacement.

Jackson, Rickman, and Pugliese begin this issue by reviewing the identification of and interventions for various infectious pathogens, both old and new. Old pathogens, particularly those that are emerging as highly virulent or resistant, and newly emerging infectious agents depend on a variety of factors for their spread and survival. Poverty, urban decay, medical advances that require concomitant immunosuppression, overuse of antibiotics, and microbial changes in virulence and drug resistance contribute to the spread of pathogens. Emerging infectious diseases are alarming, some because they were thought to be under control but have adapted and developed new virulence or resistance and others because they are unfamiliar and opportunistic. As with most problems, the key strategy for control or cure is prevention. The Centers for Disease Control and Prevention have developed a number of strategies to reduce the threat of emerging infectious diseases. The focus of these strategies is prevention-oriented public health policy, including coordinated public health efforts to develop and use surveillance systems and prevention and control programs.

Infections are cured by antimicrobials, but their overuse can cause pathogen resistance to such drugs. Guglielmo reviews the basic indications for prophylaxis, empiric therapy, and therapeutic use of antimicrobials. However, understanding that certain diseases and other causes can mimic the fevers and elevated white blood cell count of infection can prevent the unnecessary use of antimicrobials. Knowledge of the pharmacology, adverse effects, and toxicity profile of antimicrobials is critical in their selection. For a cardiovascular patient, antibiotic prophylaxis must be carefully considered and selected, reviewing general procedure-associated pathogens, such as Staphylococcus aureus, and procedure-specific prophylaxis for the prevention of endocarditis in at-risk patients. The American Heart Association in collaboration with the American Dental Association bases its recommendations for procedure-specific antibiotic prophylaxis on the pathogens known to colonize the oral cavity, and upper respiratory, gastrointestinal, and genitourinary tracts. The recommendations address uncomplicated and complicated procedures and the associated degree of patient risk. There are alternative antibiotic recommendations for penicillin-allergic patients.

Despite the vagaries of infectious agents, the degree of risk for developing a cardiovascular infection depends in large part on a patient's immunocompetence, in addition to preexisting cardiac or vascular conditions. Schell reviews physical and chemical barriers and immune system components and how they protect the body. The immune system is compromised by all of the following:

* conditions, such as malnutrition, pregnancy, diabetes, chronic alcohol or opioid use, renal and liver failure, and hematologic malignancies;

* diseases, such as systemic lupus erythematosus, rheumatoid arthritis, and viral infections;

* therapies, such as radiation therapy; and

* drugs, including corticosteroids and immunosuppressive agents.

The risk of developing a cardiovascular infection is influenced by the use of invasive devices or catheters, prosthetic graft material, or procedures that introduce a pathogen.

Cardiac infections are not particularly common, but they attack vulnerable patients, and their effect is devastating. Sparacino reviews the infectious causes and associated virulence, clinical manifestations, diagnosis, and treatment of endocarditis, prosthetic valve endocarditis, myocarditis, and pericarditis. Cardiac infections are often difficult to initially diagnose because the symptoms are either insidious or nonspecific until an infection is well-established. The infection depends on an organism's virulence and a host's susceptibility. Medical treatment includes antibiotic therapy in addition to pharmacologic hemodynamic support. Surgical intervention is necessary sometimes when heart failure is refractory to medical therapy, tissue or fluid samples are needed for diagnostic tests, or drainage of the pericardium may prevent constrictive complications. Although the mechanisms and sequelae of endocarditis, myocarditis, and pericarditis are well documented, the relationship between atheromatous lesions and infections is less well-known. Currently there is heightened interest about this relationship, especially the strong causal association among certain pathogens, such as Chlamydia pneumoniae, cytomegalovirus, and Helicobacter pylori, and the pathophysiology of atherothrombogenesis and coronary heart disease. There is also interest in whether reinfection is a trigger for acute myocardial infection.

Antimicrobial resistance is a significant cause and effect of cardiovascular infections, and resistance influences severity. Gylys discusses the mechanisms for development and spread of resistance. Resistant pathogens are not usually lethal per se, but their effect is evident in associated morbidity, increased illness severity and duration, and fewer, more expensive antibiotics. The mechanisms for developing microbial resistance are societal and molecular. Societal causes are misuse and overuse of antibiotics, inappropriate antibiotic selection, and failure to recognize resistance. Molecular mechanisms are usually a result of enzyme development or mutation that destroys the antibiotic or renders it ineffective. Bacteria are malevolent, because they can also transfer their gene coding for resistance to other organisms.

Vascular infections are even less common than cardiac infections, but they are just as serious and associated with high morbidity and mortality. Wipke-Tevis reviews the causes, pathophysiology, risk factors, and treatment. Vascular surgery is sterile, and vascular infections are usually secondary to progressive surgical wound infections and complicated by co-morbid conditions. Prosthetic graft infections are a dreaded complication, because of the associated high rate of limb amputation and death. The co-morbid conditions that increase the risk of vascular infection include, but are not limited to, diabetes, ischemic leg ulcers, and smoking. Groin graft infections are easier to diagnose than aortic graft infections, but the diagnostic tests most suggestive of infection are able to show a morphologic abnormality, such as a perigraft fluid collection, anastomotic aneurysm, hematoma, or aorto-enteric fistula. Graft infections treatment depends on the graft location and extent of infection, and a patient's condition.

Prosthetic valve endocarditis is one of the most serious cardiac infections. The clinical and patient outcome depend on the infecting organism, prompt recognition and treatment, the amount of myocardial damage, and embolic or immunologically mediated end organ damage. Hubner describes a case study of a patient with prosthetic valve endocarditis. The case study exemplifies the type of patient who is at risk, even with a two-decade interval since the initial prosthetic valve replacement. Postoperative complications are exacerbated by preoperative congestive heart failure, active infection at the time of surgery, and a history of pulmonary disease and prior embolic events. Antibiotic selection is a challenge because of negative valve tissue culture results. This patient required extensive acute and rehabilitative care, comprehensive teaching about continuing risk factors and the need for antibiotic prophylaxis, and emotional support and encouragement for a successful recovery.

Nursing care is essential in the care and treatment of a patient with a cardiovascular infection. Prevention is paramount, because a cardiovascular infection is associated with significant morbidity and mortality. The cardiovascular nurse's assessment of risk factors will help to identify a patient with a preexisting cardiac, vascular, or immunosuppressed condition, for whom the risk of intravenous contamination during a procedure or with an intravenous or intracardiac device is significant. The first step of nursing care is always a thorough assessment. In the article by McCauley, Lloyd, and Doherty, an elderly man with tachycardia of an unknown source must be thoroughly assessed before ruling out an infectious etiology to his dysrhythmia.

Prevention includes patient and family education, and nursing care that includes meticulous handwashing, antiseptic wound care and intravenous insertion site preparation and care, care of intravenous fluid admixture and delivery, and wound care. Nursing care also includes understanding the pathogenesis of cardiovascular infections, so that signs and symptoms are assessed and recognized early. The nursing management of a patient with a cardiovascular infection includes conscientious antibiotic administration, frequent assessment and monitoring of symptoms and physiologic indicators, and promptidentification of sequelae. The nursing responsibility extends to teaching patients about the importance of good nutrition, physical activity, and reduction of modifiable risk factors, such as tobacco smoking and blood glucose control.

As issue editor, I would like to thank each of the authors for sharing their knowledge and expertise with The Journal of Cardiovascular Nursing's readership.

-Patricia S.A. Sparacino, MS, RN, FAAN

Clinical Nurse Specialist; UCSF Stanford Health Care; Associate Clinical Professor; Department of Physiological Nursing, School of Nursing; University of California, San Francisco; San Francisco, California

Issue Editor

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