Cardiology

chapter 25 Cardiology



INTRODUCTION AND OVERVIEW


Cardiovascular disorders are encountered very frequently in the primary care setting. In developed or affluent countries, cardiovascular disease is still the most common cause of mortality, accounting for 38% of all deaths,1 and a significant cause of disability, particularly due to cerebrovascular disease and congestive cardiac failure. One in five Australians are affected by cardiovascular disease.2 Cardiovascular disorders are due to pathologies that arise in the:






The most common presenting complaints associated with cardiac disorders include angina, dyspnoea, palpitations and syncope. Of all cardiac conditions, the most common is coronary heart disease or ischaemic coronary syndrome.


This chapter explores the basic elements of assessing the cardiovascular system and then describes the major cardiovascular conditions presenting in the primary healthcare setting. Lifestyle and complementary therapy recommendations are made, where they can be supported by evidence.



THE INTEGRATIVE APPROACH IN CARDIOLOGY


Integrative cardiology refers to incorporation of what has been termed complementary and alternative medicine (CAM) into orthodox medical practice, including herbs, vitamins and non-herbal dietary supplements as well as therapies conducted around issues such as bioenergetics (e.g. acupuncture and energy fields) and mind–body medicine.


In 2005 the American College of Cardiology published an expert consensus document titled, ‘Integrating complementary medicine into cardiovascular medicine’.3 The authors noted that there was considerable debate regarding the clinical utility of alternative medicine practices, that these practices were widely employed by patients with cardiovascular disease and that there was a need for further research. The authors noted that ‘integrating CAM into medicine must be guided by compassion, but enhanced by science and made meaningful through solid doctor/patient relationships. Most importantly CAM involves a commitment from the clinician to the caring of patients on a physical, mental and spiritual level’.3a


Treatment of patients with cardiovascular disease follows the usual general principles of management. Lifestyle measures are employed first, then relevant CAMs, followed by drug therapy and, finally, invasive procedures and surgery.



ASSESSMENT OF THE CARDIOVASCULAR SYSTEM



CARDIOVASCULAR HISTORY


A detailed history needs to be obtained on the presenting symptoms. Based on the presenting complaint, further information should be elicited, including the following:






The above four remain the most common cardiac presentations. Once adequate information has been obtained on the presenting complaint, information about past cardiovascular history should be obtained. Any previous cardiac pathology places the patient at a high risk of recurrent similar events.









CARDIOVASCULAR EXAMINATION


The cardiovascular examination should be tailored according to the symptoms and other relevant information obtained in the history.



















CLINICAL ASSESSMENT OF THE CARDIOVASCULAR SYSTEM IN PATIENTS PRESENTING WITH POTENTIAL CARDIAC EVENTS


This section gives an outline of a structured approach to cardiovascular assessment in patients presenting with signs and symptoms indicating a significant problem of cardiac origin.


In the clinical assessment of the cardiovascular system, the most important first step is to ensure that the patient is not in imminent life-threatening danger due to cardiovascular compromise.






Urgent steps to be taken in this setting include the following:






Once the patient’s clinical stability is established, a more thorough assessment can be started.



CARDIOVASCULAR INVESTIGATIONS


Cardiovascular investigations should be guided by the differential diagnoses arrived at based on the history and the physical examination. Most patients require an ECG, a full blood count, electrolyte profile and renal function indices. Those presenting with chest pain should be further investigated for cardiac damage by performing serial serum troponin levels.


Following is a list of common cardiac investigations with indications:










RISK FACTORS FOR CARDIOVASCULAR DISEASE


Coronary artery disease remains the major cause of morbidity and mortality among the adult population in developed countries around the world. Much progress has been made in preventing and treating coronary artery disease over the past 50 years, but it is still a major health burden. Identifying and addressing coronary risk factors can effectively prevent the development and progression of coronary artery disease and cardiac events.


Non-modifiable coronary risk factors include male gender, postmenopausal state in the female, advancing age and certain ethnicities (such as indigenous groups, Pacific Islanders and African Americans).


Modifiable coronary risk factors include:











In hypercholesterolaemia, high low-density lipoprotein (LDL) and triglyceride (TG) levels are associated with heightened risk, while high high-density lipoprotein (HDL) level has a protective effect. Chronic kidney disease, proteinuria and peripheral vascular disease are important coronary risk factors. Familial hypercholesterolaemia and homocysteinuria are associated with coronary artery disease at a young age.


Psychological factors such as chronic stress and depression can contribute significantly to the aetiology and progression of cardiovascular disease, largely due to their association with sympathetic nervous system over-activation and high allostatic load. These effects are summarised in Figure 25.2.



There are also novel risk factors that have been described in the recent past. These include hyperhomocysteinaemia, high-sensitivity C-reactive protein elevation (h-CRP), elevation of lipoprotein(a) (Lpa) and hyperuricaemia. The association of these risk factors to coronary artery disease is variable and the precise means of effectively controlling these, and the absolute benefit from reducing the incidence of coronary events by doing so, are still unclear.





HYPERCHOLESTEROLAEMIA




In the management of high cholesterol levels, lifestyle measures such as dietary discretion, increased physical activity and weight loss should be given first priority. Those who fail lifestyle modification or those at high overall cardiovascular risk can be commenced on lipid-lowering therapy. Although they do not reduce lipid levels as significantly as some pharmaceuticals, omega-3 fatty acids are most effective in reducing cardiac and all-cause mortality. For LDL lowering, statins remain the most potent class of drugs, but they have significant side effects, such as muscle pain and weakness, and reduced cognitive ability. Many patients resist prescription of statins because of concern about side effects. It is important that the patient is offered an alternative plan in addition to lifestyle measures, including:









HYPERTENSION






Left untreated, hypertension can lead to disorders of various organ systems (target organ damage).










Management


Initial management of hypertension should involve lifestyle changes and weight loss as the first step. Lifestyle changes that can bring the blood pressure down include reduction in alcohol consumption, reduction in salt consumption, recreational physical activity and mental relaxation. For more severe hypertension, lifestyle changes alone will not be enough to bring the blood pressure into the desirable range and so medications are likely to be required.


A medication review for pro-hypertensive agents (see Boxes 25.1 and 25.2) needs to be performed.




However, any patient at very high overall cardiovascular risk, such as Aboriginals or Torres Strait Islanders, diabetics and those who have suffered end-organ damage, should be commenced on antihypertensive therapy in addition to the institution of positive lifestyle changes.



First-line


If lifestyle modification fails to bring about significant improvement in blood pressure, medical therapy needs to be commenced.












Pharmaceutical


When selecting antihypertensive drugs, consider potentially favourable and unfavourable effects on coexisting conditions.


Common pharmaceutical agents used in the treatment of hypertension:










According to the National Heart Foundation Guidelines of 2008, ACEs, ARBs and thiazide diuretics are to be considered first-line pharmaceutical agents.19 In cases of resistant hypertension, further investigations should be carried out to exclude a secondary cause such as renal artery stenosis or hyperaldosteronism.



CARDIOVASCULAR DISEASES



ISCHAEMIC CHEST PAIN



Chronic stable angina


Ischaemic chest pain that is brought on by exertion, after a meal or emotional stress is known as chronic stable angina. The pathology is usually a stenotic coronary lesion due to stable cholesterol plaque.





Management















Acute coronary syndrome: unstable angina and myocardial infarction


Unstable angina is chest pain of ischaemic origin that is increasing in severity and/or frequency or that has an onset at rest.


Acute myocardial infarction (AMI) is a medical emergency. Any patient with high cardiovascular risk presenting with persistent chest pain at rest should be suspected of having an AMI until proved otherwise. It is important to remember that female patients often do not present with the classic retrosternal chest tightness and therefore atypical features in the high-risk female patient should not be ignored.






Management of acute myocardial infarction


The primary objective is to restore blood flow to the infarct-related myocardium. If the ECG shows a STEMI:








The long-term management plan should be based on a firm partnership between the patient and the primary care doctor.










Preparation for coronary artery bypass surgery


In recent years the increasing incidence of high-risk and elderly patients presenting for major surgery has presented a challenge for surgeons, due to the associated increased mortality and complication rate and costs. Novel ways need to be found to improve the results of surgery in these patients. Over the past 10 years at the Alfred Hospital and the Baker Heart Research Institute in Melbourne, Australia, researchers led by Professor Franklin Rosenfeldt have developed regimens of metabolic therapy with the pyrimidine precursor, orotic acid, and the antioxidant and mitochondrial respiratory chain component, coenzyme Q10.24 Using test tube studies, animal models and human studies, they have shown that these regimens improve the response of the ageing and failing heart to hypoxia, ischaemia/reperfusion injury and aerobic stress such as occur during cardiac surgery.2429 To these original regimens, omega-3 fatty acids (fish oil supplements) and the antioxidant alpha-lipoic acid were added in an attempt to provide better clinical outcomes. The use of coenzyme Q10 supplementation as standalone treatment was validated in a clinical trial, and the entire combination of therapeutic strategies in a 1-year pilot study.25,26,30 Compared with placebo, treated patients demonstrated improved energy production in the heart muscle, increased resistance to hypoxic stress, one-day shortened hospital stay and improved postoperative quality of life.


A 3-year prospective randomised clinical trial of this integrated ‘preoperative rehabilitation’ program has been completed at the Alfred Hospital. This study demonstrated that patients experienced reduced length of stay, reduced troponin 1 release, indicating less damage to the myocardium, and, for coronary artery bypass patients, reduced incidence of postoperative atrial fibrillation, and provided a cost saving. In addition, the treatment was well tolerated and patients expressed overwhelming satisfaction with the program (results presented at the Cardiac Society of Australia and New Zealand Annual Meeting, Christchurch 2007 and at the American Heart Association Annual Scientific Sessions, Orlando Florida, November 2007, paper not yet submitted for publication).


It is on this basis that Dr Lesley Braun and Professor Franklin Rosenfeldt developed the Integrative Cardiac Surgery Wellness Program at the Alfred Hospital, which builds research conducted on site and published studies and meta-analyses demonstrating the benefits of such programs.3134 It also incorporates research produced by hospital-based integrative cardiology and health promotion units already established in the United States (such as the Mayo Clinic and the Cleveland Clinic).

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Jun 3, 2017 | Posted by in GENERAL SURGERY | Comments Off on Cardiology

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