Coronary Artery Disease ie Stable Ischemic HD

Question 1

Definition

Answer 1

• Stable Ischemic Heart Disease, CAD, and Atherosclerosis of Coronary Arteries are all synonyms
• They represent the Progressive Growth of an Atheromatic Plaque (Atheroma, Lipid-Laden Plaque, Lipid Core with a Fibrocollagenous Cap) that induces the Progressive Narrowing of an Artery’s Lumen
• Once past Critical Stenosis (ie 70% obstructed), sx will appear during times of Increased Demand, the Heart beating faster and harder, Angina with Exertion
• This is called Demand Ischemia: Sx are provoked by Increased Exertion though the Degree of Stenosis remains Unchanged. The Ischemia provokes Sx
• A reduction in the Demand (Resintg) Relieves the Ischemia and thus the Angina
• The patient experiences these things without a Myocardial Infarction, presents to the clinic, and will not have sx at the time of presentation

Question 2

Vs. MI

Answer 2

• In this session, we discuss IHD from the perspective of Slowly Progressive Stenosis of a coronary vessel.
• This information will be relevant in the next lesson, where we discuss IHD from the perspective of the Supply Ischemia Spectrum, UA, NSTEMI, and STEMI, collectively termed ACS, referred to as the diagnosis of Myocardial Infarction–where there is a Sudden and Rapid Occlusion of the Already Stenosed Coronary Artery secondary to Plaque Rupture and Thrombosis
• The two states share the same Pathogensis, Tx, and Diagnostics–through we want to build the story of Chronic Stable Angina separately from ACS

Question 3

Spectrum of Coronary Atherosclerosis = CAD = IHD

Asymptomatic IHD

Answer 3

1. Patients may have evidence of Athersclerosis but not know it. This is Asymptomatic IHD

Question 4

Spectrum of Coronary Atherosclerosis = CAD = IHD

Stable Angina

Answer 4

1. Stable Angina
   
   1. The presence of Known IHD and Demand Ischemia, called Stable IHD (SIHD).
   2. The patients have Angina with exertion.
   3. They will present Outpatient, without Elevation of the Biomarkers or ST Segments, and will not be having Angina at the time of the interview

Question 5

Spectrum of Coronary Atherosclerosis = CAD = IHD

Unstable Angina

Answer 5

1. Represents the NONTOTAL Occlusive form of Rupture and Thrombosis
2. It is identified by Angina AT REST OR PROVOKED by significantly LESS EXERTION
3. Cardiac Enzymes will NOT be elevated and there will be NO ST Segment Changes

Question 6

Spectrum of Coronary Atherosclerosis = CAD = IHD

NSTEMI

Answer 6

1. A Non ST Segment Elevation MI
2. Is also a Non-occlusive Rupture and Thrombosis
3. There are symptoms AT REST
4. The Cardiac Biomarkers ARE ELEVATED
5. but the ECG WILL NOT demonstrate ST Elevations

Question 7

Spectrum of Coronary Atherosclerosis = CAD = IHD

STEMI

Answer 7

1. STEMI represents the Occlusive Rupture and Thrombosis of the Atheroma, 100% Occlusion of the Coronary Vessel
2. Transmural ISchemia will result in Transmural Infarct if not intervened on
3. The patient will have Angina ON REST
4. The Biomarkers WILL eventually Elevate if not Elevated already
5. and there will be ST elevation in TWO OR MORE anatomically contagious leads

The Urgency Escaltes from Asymptomatic through STEMI, though disposition is divided into Outpatient (Asymptomatic and Stable)< Inpatient (UA and NSTEMI), and Cath Lab (STEMI)

Question 8

What is Angina

Answer 8

• Angina means chest pain
• Formerly, and because the first heavily studied patient population was old veterans (old men), the classic illness script for sx of Myocardial Ischemia were Substernal Chest Pain radiating Up the Jaw and Down the Left Arm, in a patient who is Cold, Clammy and with a sense of Impending Doom
• It is now known that there are many Anginal Equivalents.
• Essentially, any symptom of the “associated sx” category, could be the only symptom.
• What is most important is to know what the patient experienced during their LAST ISCHEMIC EVENT
  
  • Even through different Arteries may be affected, sx are usually the same in the same patient
  • The point is that the sx are provoked when Demand Increases and are Alleviated when Demand Decreases
  • For that Patient, Stable angina Sx will be the Same Sx of a STEMI at rest.
  • But if the Patient is not already known to have Obstructure CAD, the only way to know that the Exertional Sx is truly that patient’s Angina is to diagnose the that patient with CAD.
  • You do that by combining all the elements of the case → Hx, Physical, RF, Laboratories, an Imaging–before deciding on a Diagnostic Test
  • And which diagnostic Test is chosen depending on the LEVEL OF CERTAINTY of the diagnosis and the AGE of the patient.
  • Because this is the Stable IHD, the Atherosclerotic Disease WITHOUT Rupture and Thrombosis, the px will Present IWTHOUT ACTIVE sx, will not require Acute Diagnostics, and will not receive Acute Therapies.

Question 9

Sx

Answer 9

1. Chest Pain →
   
   1. Sx of Chest Pain are most likely to be angina if the px has had that sx before, which was Provoked by Exertion and Relieved by Rest
   2. Nitroglycerin is a Ventilator that Drops Preload, Reducing the amount of work the heart must perform
   3. Like Rest, a Decreased Amount of work Decreases the demand.
   4. a Pain that Improves with Nitroglycerin is more likely to be Angina
2. Dyspnoea, N+V, and Presyncope → Comon sx associated with eh Chest Pain of Cardiac Ischemia may be the only Presenting Sx.
   
   1. If the Chest Pain and the a/s both Respond to Exertion and Rest, the chances of Ischemia Go up

Question 10

RF

Answer 10

1. The patient’s Medical History influences the Likelihood of Atherosclerosis
2. Nonmodifiable
   
   1. Family history of Early Infarction (1st degree relative <55 in males or <65 in females)
   2. Age (45 and up for Males, 55 and up for Females)
3. Modifiable RF are the same as for Atherosclerosis
   
   1. Hypertension,
   2. Dyslipidemia
   3. Obesity
   4. Smoking
   5. Coronary Artery Disease Equivalents
      
      1. Diabetes,
      2. CKD
      3. Atherosclerotic Disease anywhere else (Vasculopathy)
   6. The more of them, the worse they are, the higher the risk.

Question 11

IX: Labs

Answer 11

1. Because they are not presenting with Sx, a Troponin-I and 12 Lead ECG ARE NOT NECESSARY
   
   1. Though evidence of Old Infarcts on the 12-lead may useful, there is no need to rule out a STEMI
   2. The assumption is that, in this lesson, the patient presents with a HISTORY of Angina and not Active Sx.
   3. Even if it is a NEW diagnosis of CAD, if the patients presents with Acute CP and is Symptomatic, get an eCG, and act as if the clinic is an urgent care.
   4. 2. Instead, the patient must be interpreted as either Low, Intermediate or High Risk
2. Low Risk Patients should not receive testing (maybe CAC)
3. Intermediate Risk and High Risk Patients get some form of Noninvasive Testing (Anatomic or Functional)
4. Stress Testing and CCTA
   
   1. If a patient has crossed the Threshold–there is a High Enough Probability of CAD that they need a Diagnostic Test–Some Diagnostic Test is performed
   2. Because the patient DOES NOT have Active sx and is in the Outpatient Setting, the Labs needed to Diagnose ACS are not needed here.
   3. The choice is between Anatomical Testing with Coronary CT Angio and Functional Testing with a Stress Test
   4. There are more options but these two illustrate the concepts.
   5. CCTA
      
      1. Is better at ruling out Obstructive CAD, and, when NEGATIVE, carries a TWO YEAR WARRANTY against Acute Ischemic Events.
      2. CCTA is therefore best used in patients with Non-Obstructive Lesions and low Chance of Disease Burden
      3. As Age is the single greatest RF for Atherosclerosis, choose CCTA to rule out Younger Patients (<65 years old)
   6. Stress Testing
      
      1. Conversely, Stress Testing is more likely to Positively Diagnose patients with Obstructive Disease and more likelihood of more Disease Burder.
      2. For patients 65 and older, use a Stress Test
      3. A Stress Test involves some form of Inducing increased Myocardial Demand (Stress) and evaluating the HEart’s Response to that demand (test)
      4. Stress comes in the form of Exercise or Pharmacological Induction
      5. Test can be a 12 lead ECG, ECHO, MRI, or Nuclear Scan
      6. The best test is an Exercise Treadmill 12-lead ECG.
         
         1. I is cheap, easy to perform, and has no radiation exposure
         2. The patient must be able to walk on a treadmill as the stress, and endure a normal baseline 12 lead ECG as the test
         3. A Positive Test is the Provocation of that patient’s Angina and ST Segment Changes, both of which go away when the patient rests
         4. A Negative Exercise Treadmill Stress Test says only that any Atherosclerosis has not reached Critical Stenosis. It doe snot rule out Coronary aRtery Disease, only makes ti very unlikely that there is a Plaque Nearing Rupture and Thrombosis.
      7. Pharmacological Induction could be via an Increase in the HR (Dobutamine), Induction of Coronary Steal (Dipryamidole), or Various other mechanisms you will not have to choose from. Use Pharamolcogical Induction when the patient cannot walk
      8. ECHO Testing is used when the Baseline 12-lead eCG is Abnormal, but the EF is normal.
         
         1. It works on the premise that dead things don’t move and Ischemic Myocardium acts like Dead Tissue.
         2. At Rest, Healthy Myocardium will Contract and Relax, while Dead, Scarred tissue will not
         3. With Increased Demand, at-risk tissue will become Ishcmeic and undergo Myocardial Stunning, and won’t move.
         4. The area of the Heart that Contracted at Rest, but does not move with Exertion is tissue that needs Repurfusion, a Positive Test
      9. Nuclear Testing is chosen when the 12 lead and the ECHO are both abnormal → A Negative Nuclear Stress Test Carries a 1-year Warranty, as compared tot the CCTA’s 2 year warrant, fitting with the Concept that the CCTA rules out disease, while a ST rules IN a disease
5. If any Non-Invasive Test is positive, the patient goes to a Confirmatory Invasive Coronary Angiogram, a Left Heart Cath.. (ICA)
   
   1. ICA, Left Heart Catheterization, Angiography, and Diagnostic Cath are all synonyms
   2. ICA is the Insertion of a Wire into an Artery (Radial or Femoral), the Threading of that Wire to the Coronary Ostia on the Aortic Valve, and the Injection of Contrast Dyde into the Coronary Vessels.
   3. The Cardiologist watches in real time on the screen as the Contrast fills the Vessels
   4. Multiple /views are obtained and Contrast is injected in each Ostium
   5. The Objective is to Identify the Number and Location of Obstructive Lesions (>50% Stenosis), as well as the Size of the Artery and how Close to the Ostia the Lesion is
   6. This informations informs HWO will Treat and HOW
   7. For a small number of relatively Small Vessels that are easily reached with a Wire, an Interventionist will open the Lesions with Angioplasty and Stents
   8. For a Larger number of Vessels, or those that re not easily reached, or a Major Proximal Vessel, a surgeon will perform a CABG.
   9. Only Obstructive Lesions should be corrected or Bypassed

Question 12

Percutaneous Coronary Intervention

Answer 12

1. PCI, Balloon Angioplasty, Stenting, and Therapeutic Cath are essentially Synonyms
2. via a Guideiwre, the Inteventionalist Threads a Balloon into the Coronary Ostium and to the Site of a Lesion
3. The Balloon’s Inflation Smushes al the Plaque-Stuff into the Wall of the Artery, Restoring the Lumen, which is confirmed by the Absence of any Stenosis after more Lumen, but will not prevent the Atheroma from Reforming (the Plaque-Stuff is still present after the Balloon is Removed)
4. To keep the Plaque-Stuff out of the Lumen, a Stent can be Placed.
   
   1. A Bare-Metal Stent (BMS), a cge longer than the lesion, is left in place
   2. Because the Stent is Foreign, the Immune System Overgrows as if it were an Atheroma, essentially Recreating the Stenosis caused by the Plaque, called Restenosis.
   3. This takes time, but not as much time as the Necrotic Lipid Core
   4. To resist Restenosis, Stents that Counteract the Immune System were created: Drug Eluting Stents: DES
   5. In Stent Thrombosis
      
      1. Essentially Rupture and Thrombosis because of the Stent, is prevented with Antiplatelets: Aspirin and the P2Y12 Inhibitors.
      2. When used together, they are called Dual Antiplatelet Therapy (DAPT)
      3. for BMS, DAPT is required for ONE MONTH
      4. For DES, CAPT is required for ONE YEAR
      5. The benefit of Preventing In Stent Thrombosis and the Risk of Bleeding are Balanced on an Individual Basis
      6. If there is No Bleeding and Low Risk for Bleeding, continue DAPT beyond 12 months
      7. DAPT can be Discontinued BEFORE 12 months if there is a Bleed or Bleeding risk is high
      8. DAPT to Monotherapy with Aspirin has been shown safe at 6 months, and DAPT to Monotherapy with a P2Y12 shown safe at 3 months.

Question 13

Coronary Artery Bypass Graft Lite

Answer 13

1. CABG is covered in Subspeciality Surgery in greater detail
2. A CABG is performed for Multiple Vessels or for one Large Important one
3. The reason for that is the Left Internal Mammary Artery (LIMA) is used to Bypass the most important Blockage
4. This requires only one Anastomosis and results in Perfusion of that coronary Vessel in Systole, as opposed to Diastole
5. All other Bypasses will be a Saphenous Vein Graft Harvested form one fo the Legs, connecting the Proximal Aorta to the Coronary Artery Distal to the Obstruction
6. Even though there is no Metal like with Stents, DAPT is used after CABG as well

Question 14

Medical Therapy for Stable IHD

Answer 14

1. The Lesion is corrected (by stent or bypass)
2. Medical Therapy is designed to
   
   1. Treat Atherosclerosis with a STATIN
      
      1. Atorvstatin 40mg, 80mg
      2. Rosuvstatin 20mg, 40mg
   2. Prevent Rupture and Thrombosis with ASPRIN 81mg
   3. Prevent Ischemic Injury and HF with BB and ACE/ARBs
      
      1. HR: Metoprolol
      2. BP: Carvedilol
      3. For patients WITHOUT a hx of Infarction and with a Normal EF, BB may be discontinued if there are no other indications
      4. ACE/ARB: Any work, use ARBs
   4. In cases of Stent or Bypass and with no Contraindications because of Bleeding, DAPT (Aspiring with a P2Y12 Inhibitor) is added for Life (or until Bleed Risk gets Unacceptably high
3. A patient may continue to have Angina, most often in Lesions that are not amenable to Procedural Correction
4. Thus, after maximizing the BB and ACE/ARB, if Exertional Angina persists, use Anti-Anginals.
5. If the BP remains Elevated, the Hypertension Medications that also provide Anginal Relief are the Dihydropyridine CCBs, such as Amlodipine, and the Nitrate Isosorbide Mononitrate.
6. The other Nitrate, Nitroglycerin, can be used on an As-Needed Schedule
7. The last ditch effort medication for Palliation of Refractory Disease only is Ranolazine