稍微來介紹一下我們對於心臟外科最常聽到的手術-冠狀動脈繞道手術.

幾乎每個人都有聽過冠狀動脈繞道手術,也都知道當心肌梗塞時(AMI)不失為另一種選擇,但是可能很多人都不是很清楚繞道手術(CABG)本身的適應症是什麼?首先先講較為人討論的CABG for emergent condition,根據2011 ACCF_AHA guildline,當AMI後產生postinfarction mechenical complication: 1) Ventricular septal rupture, 或是 2) Mitral valve insufficiency--通常為papillary muscle inafction/rutpure, 甚至產生3) Free wall rupture. 以上都為emergent CABG的 indication.此外,還有一種情形也是符合emergent CABG：當病人因為心肌梗塞而產生cardiogenic shock時,不管發生時間的長短,都應該盡快做緊急的CABG「class Ib」.最後當病人因為AMI而變成Vf時（ventricular fibrillation）也是需要進行緊急的CABG「class Ic」

當一些緊急的情況下冠狀動脈繞道手術的適應症都介紹完後,我們來看一下elective CABG的適應症吧:

I. Chronic stable angina (Canadian class I/II)-- usually mean reversible ischemia status of coronary vessels
   a. It is usually well relieved by CABG, even though not permanently so; it can also be favorably influenced by modern medical treatment, and under many circumstances by PCI 
   b. Depend on all the patient-specific risk factors for unfavorable outcome events in patients with ischemic heart disease
(通常這類的病人,預後算相對好的,對於CABG, PCI, 甚至medical Tx的反應都不錯; 所以CABG在這裡的indicaiton就變成是一個individual clinical decision)
@當然特別說一下,一般來說,1SD(sigle vessel disease)的病人是不建議做CABG的
＃Canadian class的簡介：他是一個對於angina的分期
    --> class I : Angina only during strenuous physical activity
    --> class II: Angina only during physical activity (簡單來說就是運動更容易有症狀,譬如稍微劇烈就不行了)
    --> class III: Angina within daily activity
    --> class IV : Angina at rest

   c.  2 SD : two vessel diseases
      1. CABG is not routinely indicated with mild angina
      2. CABG is indicated when P-LAD was involved or impaired LV function
  (這類的病人,一般來說PCI的預後不比CABG差,但是當lesion involves P-LAD時,或者是EF很差的病人CABG的優勢就出來了)

   d. 3 SD: three vessel diseases
      1. P-LAD involve : CABG (2 SD伴隨P-LAD都已經是CABG比較好了,3 SD當然也是)
      2. P-LAD no=> LV
                          * If LV dysfunction: CABG (though similar survival to medical Tx, CABG showed better prognosis)--這裡必須強調一點,EF差確實常常是CABG的indication但是太差卻又不適合開刀(CABG become uncertain when EF<30%)
                          * If LV good: CABG/PCI similar to medical Tx (如果LV function是好的,那麼CABG和PCI的效果是差不多的)

II. Chronic stable angina (Canadian class III/IV)--真對於這類的病人,儘管medical Tx可能是有效的,但是intervention的介入還是需要的(Despite optimal medical treatment, intervention is usually advisable)

  a. 1 SD: PCI was recommened (though no mortality benefit, increase freedom from angina)

      * If proximal LAD or EF<50% was the case : 我們會建議CABG(因為做PCI會比CABG約3倍的機會產生 recurrent angina; 5倍的機會需要再一次intervention)
   b. 2 SD: CABG was recommened, 尤其是對P-LAD or renal dysfunction的病人(此時CABG的功效雖然沒有比PCI突出很多,但是5年內的reintervention卻明顯下降很多)
   c. 3 SD: 
      1. P-LAD involve: CABG (基本上本身是3 VD又伴隨P-LAD當然需要CABG)
      2. P-LAD no=> LV
                          * If LV dysfunction: CABG (predominant survival benefit)--However, risks and benefit of CABG become more uncertain when
                             EF<30%
                          * If LV good: CABG
       (若P-LAD並沒有涉及到,則需要看LV的功能如何,如果EF功能很差,則建議CABG--除非EF差到<30%; 若LV功能是好的,其實也是建議CABG)

III. 講完stable angina後,我們該來看一下unstable angina CABG的地位了,以下將是CABG的indication:
    *這類的病人,medical treatment initially是一定要的,而internvention介入的時間點並不需要emergent,urgent即可.除非有hemodynamic unstable等情形才需要emergent surgery.

   a. 1 SD or double vessel disease with/without P-LAD
   b. 3 vessel disease or double vessel disease + DM/EF<50% +(involve P-LAD): CABG
      * If 2 SD with P-LAD only without DM/EF<50%: CABG(PCI is an alternative)
      * If 2 SD without P-LAD: PCI initally try
(3 VD當然一定是CABG; 然而2 VD又伴隨DM/EF<50%且同時有P-LAD時也是CABG; 若2 VD同時有P-LAD但是並沒有DM/EF<50%時 ,CABG還是indication,但是PCI也是一種選擇; 若2 VD並沒有伴隨P-LAD時, PCI是可以先試試看)

看完後,剛開始可能有一點痛苦,仔細消化後應該會漸入佳境,辛苦大家了