Nicotine and Ischaemic Heart Disease

In฀smokers฀20฀cigarettes฀daily฀with฀existing฀CAD,฀perfusion฀in฀several฀myocardial฀ regions฀was฀improved฀when฀cigarette฀consumption฀was฀replaced฀in฀part฀by฀nicotine฀patches฀ 14฀and฀21฀mg฀Table฀ 6.3 .฀Perfusion฀defects฀were฀improved฀signiicantly฀even฀within฀this฀ short฀period฀Table฀ 6.3 .฀There฀was฀a฀reduction฀in฀perfusion฀defect฀size฀as฀exhaled฀CO฀ levels฀fell;฀this฀reduction฀occurred฀despite฀an฀increase฀in฀patients’฀treadmill฀exercise฀dura- tion฀and฀higher฀serum฀nicotine฀levels฀compared฀with฀controls฀although฀cigarette฀con- sumption฀had฀fallen฀ [55] ฀Another฀study฀in฀156฀smokers฀20฀cigarettes฀daily฀with฀CAD฀ conirmed฀the฀reduction฀in฀angina฀frequency฀during฀nicotine฀replacement฀therapy฀after฀ they฀had฀stopped฀smoking฀ [199] .

6.4 Concluding Remarks

The฀ smoking-induced฀ changes฀ in฀ the฀ cardiovascular฀ system฀ described฀ in฀ this฀ chapter฀ should฀sufice฀to฀ensure฀that฀smoking฀is฀viewed฀very฀much฀more฀critically฀in฀future. • ฀ In฀ particular,฀ extensive฀ findings฀ indicate฀ that฀ the฀ combustion฀ products฀ of฀ tobacco฀ in฀ mainstream฀ and฀ side-stream฀ smoke฀ are฀ primarily฀ responsible฀ for฀ the฀ harmful฀ effects฀ repeatedly฀ ascribed฀ to฀ nicotine.฀ While฀ numerous฀ authors฀ have฀ implicated฀ nicotine฀ in฀ terms฀ of฀ vasoconstrictor฀ effects,฀ the฀ large฀ body฀ of฀ evidence฀ accumulated฀ following฀ administration฀of฀nicotine฀for฀smoking฀cessation฀or฀at฀least฀for฀smoking฀reduction฀now฀ militates฀against฀the฀theory฀that฀nicotine฀might฀trigger฀a฀myocardial฀infarction฀or฀stroke฀ or฀promote฀PAOD.฀Experimental฀animal฀work฀appears฀to฀indicate฀that฀the฀toxic฀products฀ of฀tobacco฀smoke฀may฀also฀undergo฀bioactivation฀in฀the฀tissues฀of฀the฀blood฀vessels. • ฀ The฀interrelationships฀depicted฀in฀Fig.฀ 6.10 ฀are฀intended฀to฀illustrate฀these฀concepts฀once฀ again.฀Smokers฀rarely฀perceive฀themselves฀to฀be฀at฀increased฀risk฀in฀terms฀of฀myocardial฀ infarction฀or฀bronchial฀carcinoma.฀In฀a฀comprehensive฀survey฀of฀both฀diseases,฀these฀ risks฀ were฀ acknowledged฀ by฀ only฀ 39฀ and฀ 49฀ of฀ respondents฀ respectively,฀ and฀ less฀ educated฀ smokers฀ were฀ deinitely฀ less฀ likely฀ to฀ perceive฀ any฀ increased฀ personal฀ risk฀ [200] .฀Comprehensive฀analysis฀of฀the฀effects฀of฀nicotine฀on฀the฀development฀of฀arterio- sclerosis฀continues฀to฀be฀controversial฀and฀unclear,฀even฀though฀the฀alkaloid฀is฀known฀to฀ activate฀the฀sympathetic฀nervous฀system.฀In฀experimental฀animal฀studies฀nicotine฀has฀ been฀suspected฀of฀accelerating฀the฀progression฀of฀arteriosclerosis฀activation฀of฀fatty฀ acid฀metabolism,฀reduced฀HDL฀turnover;฀on฀the฀other฀hand,฀however,฀there฀are฀no฀ind- ings฀to฀support฀an฀increase฀in฀hypertension฀or฀activation฀of฀platelet฀aggregation฀ [201] . • ฀ Short-term฀interventions฀involving฀primary฀prevention฀programmes฀over฀several฀weeks฀ physical฀exercise,฀temporary฀smoking฀cessation฀do฀not฀improve฀vascular฀endothelial฀ function฀in฀adults฀with฀increased฀coronary฀risk฀factors฀ [202] . • ฀ Furthermore,฀the฀level฀of฀smoking-related฀information฀available฀in฀some฀countries฀is฀ truly฀ deplorable.฀ Even฀ smokers฀ who฀ have฀ survived฀ an฀ acute฀ myocardial฀ infarction฀ receive฀only฀inadequate฀advice฀from฀the฀physicians฀treating฀them.฀According฀to฀one฀ study฀conducted฀in฀Israel,฀only฀62฀of฀such฀patients฀reported฀receiving฀anti-smoking฀ advice฀ [63] . Reference ฀ 1.฀Doll฀R,฀Peto฀R,฀Wheatley฀K,฀Gray฀R,฀Sutherland฀I฀1994฀Mortality฀in฀relation฀to฀smoking:฀ 40฀years’฀observations฀on฀male฀British฀doctors.฀BMJ฀3096959:901–911 ฀ 2.฀Hammond฀EC,฀Garinkel฀L฀1969฀Coronary฀heart฀disease,฀roke,฀and฀aortic฀aneurysm.฀Factors฀ in฀the฀etiology.฀Arch฀Environ฀Health฀192:167–182 ฀ 3.฀Abbott฀RD,฀Yin฀Y,฀Reed฀DM,฀Yano฀K฀1986฀Risk฀of฀stroke฀in฀male฀cigarette฀smokers.฀N฀Engl฀ J฀Med฀31512:717–720 ฀ 4.฀Adamson฀J,฀Humphries฀SE,฀Ostergaard฀JR,฀Voldby฀B,฀Richards฀P,฀Powell฀JT฀1994฀Are฀cere- bral฀aneurysms฀atherosclerotic?฀Stroke฀255:963–966 ฀ 5.฀Fitzgerald฀GA,฀Oates฀JA,฀Nowak฀J฀1988฀Cigarette฀smoking฀and฀hemostatic฀function.฀Am฀ Heart฀J฀1151฀Pt฀2:267–271 ฀ 6.฀Fowkes฀FG฀1988฀Epidemiology฀of฀atherosclerotic฀arterial฀disease฀in฀the฀lower฀limbs.฀Eur฀ J฀Vasc฀Surg฀25:283–291 ฀ 7.฀Kannel฀WB,฀Shurtleff฀D฀1973฀The฀Framingham฀study.฀Cigarettes฀and฀the฀development฀of฀ intermittent฀claudication.฀Geriatrics฀282:61–68 ฀ 8.฀Haustein฀KO฀1999฀Smoking,฀cardiovascular฀diseases฀and฀possibilities฀for฀treating฀nicotine฀ dependence.฀Wien฀Med฀Wochenschr฀1491:19–24 ฀ 9.฀Haustein฀KO,฀Krause฀J,฀Haustein฀H,฀Rasmussen฀T,฀Cort฀N฀2002฀Effects฀of฀cigarette฀smoking฀ or฀nicotine฀replacement฀on฀cardiovascular฀risk฀factors฀and฀parameters฀of฀haemorheology.฀J฀ Intern฀Med฀2522:130–139 10.฀LaCroix฀ AZ,฀ Lang฀ J,฀ Scherr฀ P,฀ Wallace฀ RB,฀ Cornoni-Huntley฀ J,฀ Berkman฀ L,฀ et฀ al฀ 1991฀ Smoking฀and฀mortality฀among฀older฀men฀and฀women฀in฀three฀communities.฀N฀Engl฀J฀Med฀ 32423:1619–1625 Nicotine Carbon monoxide Apoplexia Sudden heart death Tissue hypoxia, myocardial hypoxia, Myocardial ischaemia CO-Hb ? BP, HR at diminished oxygen transport Sympathetic nervous system Myocardial contractility ? vasoconstriction ? Acute myocardial infarction Benzpyrenes, glycoproteins Platelet aggregation, fibrinogen,Oxo-LDL, Formation of O-radicals, Damaged endothial cells Atherogenesis, hypertension, peripheral arterial occlusive disease Fig. 6.10 ฀฀฀Effects฀of฀nicotine฀and฀the฀combustion฀products฀of฀cigarette฀smoke.฀BP฀blood฀pressure,฀ HR฀heart฀rate