Angina pectoris 狭心症 a syndrome characterized by paroxysmal, constricting pain below the sternum, most easily precipitated by exertion or excitement and caused by ischemia of the heart muscle, usually due to a coronary artery disease, as arteriosclerosis. Angina: (語源) any attack of painful spasms characterized by sensations of choking or suffocating. < L angina quinsey, for * ancina < Gk strangulation, hanging 病態治療原則男性、中年季節：冬寒冷暴露次の有名な絵を見て，狭心症の発作につながる因子を挙げよ大食後重い荷物階段登りタバコ前胸部痛図４-２心筋酸素需要・供給と狭心症の病態収縮力血圧（後負荷）心拍数左心室圧心室容積酸素供給酸素需要冠動静脈酸素含有量の較差心筋酸素分布冠血流量大動脈圧 (拡張期) 冠血管抵抗壁張力静脈還流（前負荷）虚血自覚症状狭心痛心電図異常代謝障害心室機能不全 ST下降（労作性狭心症）乳酸・Ｈ+ の産生壁運動異常 ST上昇（安静時狭心症）Ｋ +の漏出拡張終期圧上昇不整脈アデノシン遊離心拍出量低下狭心痛の部位と放散心拍出量の分配率と酸素消費臓器脳心臓肝臓腎臓骨格筋皮膚その他全身血流量 O2消費量 ml/ 分（臓器100g当たり） ml/ 分（全臓器当たり）分配率（％）ml/ 分（全臓器当たり）消費率（％） 57 750 15 46 20 70 200 4 27 11 95 1,350 27 33 14 420 1,200 24 16 7 3 850 16 70 30 7 350 7 5 2 400 7 36 16 5,100 100 233 100 動脈血には20 vol% の酸素が含まれている O2 extraction vol% CaO2 – CvO2 心臓11.5%，脳6.4、肝臓4.1、腎臓1.3、骨格筋静止時4.3、最大運動時17.2 Lead V4 at rest (top) and after 4.5 min of exercise (bottom). There is 0.3 mV of horizontal ST-segment depression, indicating a positive test for ischemia. Coronary Angiography Stenosis: narrowing of the artery, due most likely to atherosclerosis. Damage to the intima due to atherosclerosis is a major cause of thrombosis in the arteries. The resultant ischemia of the myocardium can lead to ischemic necrosis, i.e., an infarct [Myocardial Infarction]. 1.What therapeutic agent can be used to lyse the clots in coronary vessels? 冠動脈硬化 Coronary atherosclerosis 内膜下のプラーク生成血栓生成の可能性 Spasm発生の可能性冠動脈血栓 Coronary thrombosis 内皮細胞機能血小板マクロファージ増殖型平滑筋細胞図2-20参照、さらに病理学で学んでください。 Dynamic coronary obstruction Spasm Rest angina tone tone Dynamic coronary obstruction • This figure shows how the caliber of eccentric coronary artery stenoses may change, with considerable variation in the degree of stenosis resistance and the propensity to produce angina. • Both increased vascular tone (first two examples, spasm & tone ) and decreased vascular tone (third example) are depicted. 狭心症 angina pectoris の分類 (p.139) 安定狭心症器質性（労作性） Stable (typical) angina プリンツメタル型狭心症 Prinzmetal (variant) angina 冠動脈攣縮型（異型）不安定狭心症梗塞前 Unstable (crescendo) angina 安定狭心症・安定プラークによる冠状動脈（ＬＡＤ，ＬＣＸ，ＲＣＡ）の内腔狭窄『酸素需要＞酸素供給』→休息により改善冠動脈攣縮 spasm 血管平滑筋の過剰収縮冠血管狭窄冠血流量減少プリンツメタル型狭心症 •冠状動脈のspasm （攣縮）による（plaque プラークの近傍） •休息・睡眠時 ←運動・血圧・心拍数に無関係 •喫煙がリスクファクター •より若年で発症。予後比較的良好。 •ST-segment elevation ←貫壁性の虚血不安定狭心症 (Preinfarction angina) ・不安定プラークの崩壊（アテローム内出血、機械的ストレス↑） →血栓形成・Vasospasm→一時的内腔閉塞・心筋梗塞へ移行しやすい →動脈硬化病変が不安定であり、続発性の血栓形成が起こりやすい・頻度が増大、発作の延長。休息時にも起こる。動脈硬化から見た狭心症閉塞性血栓 1 白色血栓症動脈壁の異常血小板とフィブリンが主役閉塞性血栓 2 赤色血栓症プラークの破綻凝固因子が主役図4-１冠動脈硬化およびスパスムと狭心症治療薬の位置付け中膜血栓症の可能性平滑筋層（収縮・弛緩）内皮内腔内膜冠拡張薬 Ca拮抗薬Ｋ + チャネル開口薬など脂質・アテローム冠動脈スパスム（攣縮） β遮断薬動脈硬化（器質的狭窄）亜硝酸化合物、抗血小板薬抗脂血症治療薬 Correction of the imbalance increasing delivery (by increasing coronary flow) nitrates (nitroglycerin) vasodilators (Ca antagonists, KCOs) coronary bypass grafts or angioplasty (PTCA) percutaneous transcatheter coronary angioplasty decreasing oxygen demand (by decreasing cardiac work) b-blockes, nitrates nitrates (nitroglycerin) vasodilators (Ca antagonists, KCOs) 図４-２心筋酸素需要・供給と狭心症の病態収縮力血圧（後負荷）心拍数左心室圧心室容積酸素供給酸素需要冠動静脈酸素含有量の較差心筋酸素分布冠血流量大動脈圧 (拡張期) 冠血管抵抗壁張力 small oxygen debt: extract about 75% of available oxygen ‘tachycardia’-- harmful 静脈還流（前負荷）虚血自覚症状狭心痛心電図異常 ST下降（労作性狭心症）代謝障害 + 乳酸・Ｈの産生心室機能不全 ST上昇（安静時狭心症）Ｋ +の漏出拡張終期圧上昇不整脈アデノシン遊離心拍出量低下壁運動異常冠状動脈の分岐（A）と血流量変化（B）. 時間 (秒）心周期中に冠状動脈の血流は変化する。 2本の点線の間は心室の拍出期で、大動脈圧は高いが、左心室の内圧がさらに高いために左冠状動脈の血流は減少している。(図15-24，生理学テキスト） Artery blocked by thrombus on fissured atherosclerotic plaque Zone of perfusion (area at risk) next Myocardium 0 hr 2 hr 24 hr Obstructed coronary art. Endocardium area at risk Zone of necrosis Zone of necrosis Epicardium Progression of myocardial necrosis after coronary artery occlusion. Necrosis begins in a small zone of the myocardium beneath the endocardial surface in the center of the ischemic zone. This entire region of myocardium (dashed outline) depends on the occluded vessel for perfusion and is the area at risk. Note that a very narrow zone of myocardium immediately beneath the endocardium is spared from necrosis because it can be oxygenated by Principle of stress radionuclide imaging for the detection of coronary artery disease. (1) a normal coronary artery and an artery with significant stenosis (top), (2) the myocardial territory (perfusion image), and (3) the ventricular wall (wall motion image) supplied by each artery. Distribution of regional myocardial blood flow • The distribution of regional myocardial blood flow in the myocardium is heterogeneous, i.e., there is less blood flowing in the ischemic myocardial bed (blue area) than in the normal myocardial bed. Coronary blood flow at rest and during stress (x ～5) 最大運動時 Coronary blood flow at rest and during stress (1) At rest, coronary blood flow is similar in the normal artery and in the artery with stenosis. Resting coronary blood flow in the diseased artery is maintained at a normal level and is sufficient to meet resting metabolic myocardial demands because of recruitment of coronary reserve (dilatation of the resistance vasculature) in the distal coronary bed. During exercise, myocardial metabolic demands increase and more myocardial nutrient blood flow is required. Coronary reserve is increased as a result of dilatation of the coronary resistance vessels in the peripheral coronary bed. Coronary blood flow at rest and during stress (2) In the territory of the normal coronary artery, the resistance vessels dilate and coronary blood flow is increased by 2 to 2.5 times. In the abnormal coronary bed, which is distal to the significant coronary stenosis, resistance vessels are already dilated and little if any further dilatation is possible. Increased metabolic demands thus cannot be met, and the relatively hypoperfused myocardium becomes ischemic.