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General Reference

Nejm 1993;329:247 [women]

Pathophys and Cause

Cause:Multiple, including elevated cholesterol (Nejm 1981;304:65); smoking, passive (Nejm 1999;340:920) and active, correlates most w pack-years not w quitting (Jama 1998;279:119); hypertension; genetic, especially in women; Hgb A1C level >5 (Ann IM 2004;141:413, 421, 475). Possibly induced by Chlamydia pneumoniaeendovascular infection in cardiovascular disease (Jama 1999;281;427, 461—though 1 wk rx w azithromycin to pts w stable CAD does not decr recurrence; Nejm 2005;352:1637, 1646, 1706), as well as vascular dementia (Jags 2005;53:583), or other causes of inflammation indicated by elevated CRP levels (Nejm 2002;347:1557, 1615; Jama 1999;282:2131, 2169) and interleukin-6 (Jama 2002;288:980); but no correlation between chlamydial IgG titers and ASHD found in women (Ann IM 1999;131:573)

Pathophys:(Nejm 1999;340:115) Wall stress causes fibrous plaques, which later infiltrate with cholesterol; impaired fibrinolysis may also play a role in genesis. Onset by age 18 yr (Nejm 1986;314:138). Hemorrhage into plaque causes sudden occlusions

Epidemiology

Increased incidence in Western countries although it has decreased in last 25 yr, half due to decrease in risk factors and half due to medical rx (Nejm 1996;334:884) w improving post-MI survival (Nejm 1998;339:861)

Increased in diabetes, hypertension, obesity (Nejm 1990;322:882), inflammation as measured by sCRP and h/o acute infections (Nejm 2004;351:2599, 2611), air pollution (Nejm 2007;356:447), smokers perhaps via inflammation (CRP) and homocysteine levels (Ann IM 2003;138:891), pseudoxanthoma elasticum, myotonic dystrophy, alkaptonuria and ochronosis; homocystinuria/emia (Homocystinuria (Homocyst[e]inemia)) consumers of food w partially hydrogenated transfatty acids (Nejm 2006;354:1601); hyperlipidemias (Hyperlipidemias) especially LDL elevations often associated w apolipoprotein (epsilon) E4 allele (Jama 1994;272:1666), and w elevated lipoprotein (alpha.gif) (Jama 1996;276:544); sleep disorders (Am J Med 2000;108:396); adults who were low-birth-weight children to age 2+ yr (Nejm 2005;353:1802, 1848).

Weak (ACP J Club 1998;129(2):50) or no association w triglyceride elevations alone, although they are markers for other risk factors (Nejm 1993;328:1220)

Decreased in moderate (7-20 drinks/wk) alcohol drinkers (Jama 1999;282:239; Nejm 1997;337:1705, Ann IM 1997;126:372, Nejm 1995;332:1245; 1993;329:1829), via increased TPA as well as HDL (Jama 1994;272:929) and flavins in red wine which appears to decr cancer mortality in addition (Ann IM 2000;133:411); in runners (Nejm 1980;303:1159), and otherwise regularly exercising men (Nejm 1998;338:94, 1993;328:533, 538, 574; 1993;329:1829) and women (Jama 2001;285:1447) via protective elevations of HDL cholesterol component; with high fiber diets (20+ gm qd) (Jama 1999;281:1995) like those high in fruits and vegetables (Ann IM 2001;134:1106); with increased fish intake of omega-3 or N-3 fatty acids (see Atherosclerosis); Mediterranean diet (Nejm 2003;348:2599)

Signs and Symptoms

Sx:Claudication, angina, MI, sudden death, TIA/CVA, abdominal angina

Si:Renal hypertension; bruits, absent peripheral pulses; CVAs; arcus senilis in Caucasians age <50 yr (Nejm 1974;291:1323) is a risk factor independent even of cholesterol levels (Am J Publ Hlth 1990;80:1200); retinal fundal vessel plaques, arterial narrowing correlates w MI risk in women but not men (Jama 2002;287:1153)

Complications

All of above

Lab and Xray

Lab:

Chem:Cholesterol (Hypercholesterolemia) Apolipoprotein A2 (Nejm 2000;343:1149) (components of HDL) may be better predictors

Hem: sCRP levels >1.55 mg/L, of doubtful utility (Nejm 2004;350:1450) but may ID candidates for primary statin preventive rx (Nejm 2008;359:2195, 2280)

Path:Lipid in foam macrophages and smooth muscle; free cholesterol crystals between intima and media

Xray:Electron beam CT screening of unproven value (Nejm 1998;339:1964, 1972, 2014, 2018)

Treatment

Rx:

Prevent (Ann IM 2005;142:393)

  • Stopping smoking
  • Cholesterol LDL elevation rx (Klinefelter's Syndrome) to get <100 mg % (Nejm 1997;336:153, Circ 1994;89:1329) at least in pts w ASHD; helps both by decreasing plaques and by preventing coronary artery spasm (Nejm 1995;332:481, 488); low saturated rather than low total fat diet (Jama 2002;288:2519) incr fruits vegetables and whole grains; Indo-Mediterranean (Lancet 2003;360:1455, Nejm 2003;348:2599)
  • Cholesterol HDL depression; try to get over 60, at least over 40 w niacin (Nejm 2009;361:2113, 2180)
  • Alcohol at 2-3 drinks qd decreases mortality by 25% (Am J Publ Hlth 1993;83:805)
  • Omega-3 or N-3 fatty acids, as qd capsule (Lancet 1999;354:447) or 1 fatty fish meal/day-mo decreases incidence of cardiac arrest by up to 50% (Jama 2002;287:1815; ACP J Club 2000;132:6; Nejm 1997;336:1046), which also decr stroke risk by 50% (Jama 2001;285:304) and sudden death (Nejm 2002;346:1113); counteracted by mercury content of fish (Nejm 2002;347:1747) but risk/benefit ratio worth it (Jama 2006;296:1885)
  • Carbohydrate reduction and replacement with vegetable fats and protein (Nejm 2006;355:1991)
  • Exercise (Jama 2001;285:1447; 1998;279:440) moderate (2-3 mph) walking 1-2 hr/wk; total more important than intensity; increases fibrinolysis (Nejm 1980;302:987)
  • Rx of diabetes and hypertension
  • ASA 80-320 mg (Nejm 2005;352:1293 [women]; USPSTF in Ann IM 2002;136:157; ACP J Club 2001;135:88) po qd decr MIs (men) and CVAs (women) especially if CRP chronically elevated (Nejm 1996;336:973, 1014); primary prevention in diabetics (Jama 2008;300:2134); effect is counteracted by ibuprofen but not acetaminophen or diclofenac (Voltaren) (Med Let 2004;46:61)
  • ACE inhibitors in pts w diabetes or vascular disease and other risk factors decr MI, sudden death, and CVAs, even if normal EF, NNT-4 = 14 (Nejm 2000;342:454)
  • No help from:
    • Folic acid and/or vit B6, and/or vit B12 and may incr cancer and mortality (Jama 2010;303:2486; 2009;302:2119, 2152; 2008;299:2027; 300:795)
    • sCRP (Jama 20098;302:49,92; Ann IM 2006;145:35, 70), no point in reduction strategies
    • Vit E, antioxidant; DBCTs show deleterious, all cause mortality and CHF effect (Ann IM 2005;142:37; Jama 2005;294:52; 293:1338; Nejm 2001;345:1583; 2000;342:154; Jama 2002;288:2432). No stroke reduction either (Ann IM 1999;13:963)
    • EDTA chelation of various heavy metals (Med Let 1994;36:48)
    • beta.gif-carotene (Nejm 1996;334:1145, 1150, 1189, Jama 1996;275:693, 699—ERT) (Estrogen Replacement Therapy) of disease, various tertiary maneuvers to fix damage especially surgery, eg, angioplasty/CABG, femoral-popliteal bypass, etc; plus dietary measures, eg, "Mediterranean diet" reduces subsequent mortality from 5% to 1% (Arch IM 1998;158:1181; Lancet 1994;343:1454) and can reverse ASHD vessel diameter narrowing (Jama 1998;280:2001; Ann IM 1994;121:348)