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Pathology

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Description

Cardiovascular disease refers to the class of diseases that involve the heart and/or blood vessels (arteries and veins). While the term technically refers to any disease that affects the cardiovascular system, it is usually used to refer to those related to atherosclerosis (arterial disease). These conditions have similar causes, mechanisms, and treatments.

Over 50 million Americans have cardiovascular problems, and most other Western countries face high and increasing rates of cardiovascular disease. It is the number 1 cause of death and disability in the United States and most European countries. By the time that heart problems are detected, the underlying cause (atherosclerosis) is usually quite advanced, having progressed for decades. There is therefore increased emphasis on preventing atherosclerosis by modifying risk factors, such as healthy eating, exercise and avoidance of smoking.

Discussion

Forms

Cardiovascular disease usually occurs as a result of arterial damage. The symptoms and treatments depend on which set (or sets) of arteries are affected.

In coronary heart disease, atherosclerotic plaques (inflamed fatty deposits in the blood vessel wall) obstruct the coronary arteries (blood vessels supplying the heart). Narrowing of arteries is called arterial stenosis. When the blockages become severe enough, the blood flow to the heart is restricted (cardiac ischemia), especially during increased demand (i.e. during exertion or emotion). This results in angina pectoris. The acute stage of coronary heart disease occurs when one of the plaques ruptures, forming a thrombus (blood clot) that acutely occludes the whole artery. The portion of the heart muscle supplied by that artery dies; this is known as a myocardial infarction (or a heart attack in lay parlance). This may result in the death of the patient if the affected area is large enough. If the patient survives, congestive heart failure may result.

Similarly, inflammation and blood clots may obstruct the cerebral arteries (those supplying the brain). As the disease progresses, an artery may be transiently blocked, causing cerebral ischemia. This results in a transient ischemic attack (TIA), called a mini-stroke in lay parlance. If the obstruction is severe, a cerebrovascular accident, or stroke may result, due to the death of brain tissue supplied by the artery.

In peripheral artery disease, obstruction occurs in the arteries of the arms or legs. This results initially in pain, during temporary obstruction, and finally in tissue death and gangrene if not treated.

There are many specific illnesses that may occur in association with these and other cardiovascular disease. In addition to the ones mentioned above, these include hypertension (high blood pressure), arterial aneurysms (arterial enlargement and weakening), cardiomegaly (abnormal enlargement of the heart), tachycardia/bradycardia/arrhythmia (fast/slow/irregular heart rates), cardiac arrest (heart stoppage), cardiomyopathy (heart muscle weakness), heart valve regurgitation (leakage), and heart valve stenosis (narrowing).

Risk factors

There are many risk factors which predispose to various forms of cardiovascular disease. These include the following:

  • Age
  • Diabetes mellitus
  • Hypercholesterolemia (elevated cholesterol levels) and less than excellent lipoprotein particle profile (cholesterol subtypes)
  • Tobacco smoking
  • Higher fibrinogen and PAI-1 blood concentrations
  • Elevated homocysteine, or even upper half of normal
  • Elevated blood levels of asymmetric dimethylarginine
  • High blood pressure
  • ABO blood group A or AB
  • Obesity, especially central or female-type obesity; apart from being linked to diabetes, this form of obesity independently increases cardiovascular risk, presumedly by inducing an inflammatory and procoagulant state
  • Genetic factors/Family history of cardiovascular disease
  • Physical inactivity
  • Being a member of the female sex

Although men have a higher rate of cardiovascular disease than women, it is also the number one health problem for women in industrialized countries. After menopause, the risk for women approaches that of men. Hormone replacement therapy alleviates a number of post-menopausal problems, but appears to increase the risk of cardiovascular disease.

Abstracts

Myocardial infarction in women under 50 years of age

Rosenberg L, Miller DR, Kaufman DW, Helmrich SP, Van de Carr S, Stolley PD, Shapiro S

JAMA 1983 Nov 25;250(20):2801-2806

  • Risk factors for first nonfatal myocardial infarction (MI) in women younger than age 50 years were evaluated in a case-control study of 255 women with MI and 802 controls. The relative risk of MI increased with the amount smoked. The estimated risk of MI for current smokers of 35 or more cigarettes per day was ten times that of women who never smoked; an estimated 65% of MIs were attributable to cigarette smoking. The relative risk of MI increased markedly with increasing levels of total plasma cholesterol and decreasing levels of high-density lipoproteins, and the effects of the two factors appeared to be independent. Other factors significantly associated with MI were hypertension, angina pectoris, diabetes mellitus, blood group A, and a history of MI or stroke before age 60 years in a mother or sibling. Factors not significantly associated with MI were obesity, history of preeclamptic toxemia, and type A personality. Women who were postmenopausal appeared to have a lower risk of MI than premenopausal women of similar ages. Of the identified risk factors, the most prominent was cigarette smoking, a habit that is amenable to change.
Factor VIII, ABO blood group and the incidence of ischaemic heart disease

Br J Haematol 1994 Nov;88(3):601-607 Meade TW, Cooper JA, Stirling Y, Howarth DJ, Ruddock V, Miller GJ MRC Epidemiology and Medical Care Unit, Wolfson Institute of Preventive Medicine, Medical College of St Bartholomew's Hospital, London.

  • Relations of factor VIII activity, FVIIIC, and von Willebrand factor antigen (vWFAg), with ischaemic heart disease (IHD) were examined in 1393 men aged between 40 and 64 years at entry to the Northwick Park Heart Study (NPHS) who experienced 178 first major episodes of IHD during an average follow-up period of 16.1 years. Thus, an increase of 1 standard deviation in FVIIIC raised the risk of fatal IHD by about 28%. vWFAg was also significantly associated with fatal events. FVIIIC and vWFAg were strongly correlated (r = 0.57) and in statistical terms there may be little to choose between them in long-term studies of IHD. Taking account of evidence that haemophiliacs seem to experience less IHD than expected, high factor VIII levels may contribute to the incidence of IHD by increasing thrombogenic potential. The incidence of IHD was significantly higher in those of blood group AB than in those of groups O or B, particularly for fatal events. There was no evidence that the FVIIIC and vWFAg associations with IHD are determined by ABO group. The factor VIII and ABO blood group effects therefore appeared to be independent. GroupAB may be a genetic markers of characteristics influencing other indices of IHD risk such as short stature, NPHS men (though not women) of group AB being about 2 cm shorter than those of other groups.
ABO and Rh blood groups in cardiovascular pathology

[Article in Russian] Meshalkin EN, Okuneva GN, Vlasov IuA, Vel'tmander NN Kardiologiia 1981 Apr;21(4):46-50

  • A relationship between erythrocytic antigens of the ABO and Rh blood systems and cardiovascular pathology was revealed by comparing the distribution of blood groups in 13,175 patients and 7,800 donors. Prevalence of A gene and Rh+ phenotype in congenital and acquired heart diseases and ischemic heart disease was found. The frequency of B gene is increased in patients with acquired heart diseases.
Association between polymorphic blood markers and risk factors for cardiovascular disease in a large pedigree

George VT, Elston RC, Amos CI, Ward LJ, Berenson GS

Genet Epidemiol 1987;4(4):267-275 Department of Biometry and Genetics, Louisiana State University Medical Center, New Orleans 70112-1393.

  • A large pedigree with high prevalence of heart disease is investigated to analyse the association between polymorphic blood markers and quantitative risk factors for cardiovascular disease. The analysis incorporates a familial correlation structure among the individuals in the pedigree and a generalized power transformation to induce approximate residual normality of the risk factors. A total of 380 marker/risk factor combinations are analysed, and at the normal 1% significance level, positive associations are found between the A antigen of the ABO locus and both serum total cholesterol and low-density lipoprotein cholesterol, and negative associations are found between the B antigen of the ABO locus and serum total cholesterol, and between the B allele of acid phosphatase (AP) locus and systolic blood pressure
ABO blood groups and coronary heart disease (CHD). A study in subjects with severe and latent CHD

Thromb Haemost 1980 Jun 18;43(2):137-140 Erikssen J, Thaulow E, Stormorken H, Brendemoen O, Hellem A

  • The view based on epidemiological and laboratory data that blood group A subjects (=A) have clinically significant higher thrombotic potential than blood group 0 subjects (=O), is supported by the present finding of a significantly higher platelet retention in A than 0. The completely normal AB0 distribution found among 71 cases of proven latent CHD, and the disproportionate excess of 0 vs. A in a consecutive series of 191 coronary artery bypass candidates apparently conflict with epidemiological data indicating a higher risk of achieving CHD in A than 0. The conflict may be solved by suggesting a) that the "thrombotic proneness" in A compared with 0 causes a poorer prognosis in CHD among the former, leaving a disproportionate excess of 0 among longterm CHD survivors, and b) that AB0-related factors have had an insignificant, independent impact on the evolution of preclinical coronary artery disease in our 71 men with latent CHD.
ABO blood-group phenotypes and pathogenesis of cardiovascular diseases. Congenital, rheumatic and coronaric heart disease and arterial hypertension

G Ital Cardiol 1975;5(5):744-751 Galeazzi L, Gualandri V

  • Many cases of cardiovascular diseases have been examined in reference to the distribution of ABO blood-groups, in order to calculate the relative risk of disease and the hemogroupal distributive significance in our samples as related to those of other authors, using combined calculation. The analysis concerned the following cases: 746 with arterial hypertension, 3258 with congenital heart disease, 4503 with articular rheumatism, 1047 with acquired valvulopathia, and respective controls. It was found that blood-group phenotypes represent an important biophysiopathological action in regard to articular rheumatism and its cardiac consequences, in myocardial infarction and in hypertension, males only. It shows itself in: -- a significant negative association with group O and positive association with group A in the myocardial infarction; -- a significant negative association with group O and positive for the others in the valvulopathic (rheumatic) diseases; -- a positive association with A phenotype and negative with B in arterial hypertension, males only; -- no association with ABO blood-groups and congenital heart disease.
ABO blood groups, age and work in ischaemic heart disease

Atherosclerosis 1975 May;21(3):459-461 Allan TM

  • In a series of male survivors of ischaemic heart disease there were fewer patients belonging to the risk-factor blood group (group A) before than after age 55 who were either non-infarction patients in light work or infarction patients in active or heavy work. Conversely, there were more A's before than after age 55 who were either non-infarction patients in active or heavy work or infarction patients in light work.
ABO blood group and ischaemic heart disease in British men

BMJ 1990 Jun 30;300(6741):1679-1682 Whincup PH, Cook DG, Phillips AN, Shaper AG Department of Public Health and Primary Care, Royal Free Hospital, School of Medicine, London.

  • OBJECTIVE--To establish whether ABO blood group is related to ischaemic heart disease on an individual and geographic basis in Britain. DESIGN--Prospective study of 7662 men with known ABO blood group selected from age-sex registers in general practices in 24 British towns. END POINTS--Eight year follow up of fatal and nonfatal ischaemic heart disease events achieved for 99% of study population. RESULTS--Towns with a higher prevalence of blood group O had higher incidences of ischaemic heart disease. In individual subjects, however, the incidence of ischaemic heart disease was higher in those with group A than in those with other blood groups (relative risk 1.21, 95% confidence limits 1.01 to 1.46). Total serum cholesterol concentration was slightly higher in subjects of blood group A. No other cardiovascular risk factor (including social class) was related to blood group. CONCLUSIONS--Blood group A is related to the incidence of ischaemic heart disease in individual subjects. Geographic differences in the distribution of ABO blood groups do not explain geographic variation in rates of ischaemic heart disease in Britain. The findings do not support the view that ABO blood group and social class are related.

Attribution

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