13. Cardiovascular Disease Flashcards
Define hypertension
How is it diagnosed?
How is it classified?
Persistently elevated arterial blood pressure of 130/80 or higher in adults
Diagnosed by 2 elevated readings of at least 130/80 mmHg on 2 or more visits
AHA and ACC update to JNC7 classification:
- Normotension <120/80
- Elevated 120-129/<80
- Stage I 130-139/80-89
- Stage II >140/90
Calcium channel blockers
Decrease influx of calcium ions resulting in vasodilation and reduction in blood pressure (amlodipine, felodipine, diltiazem, verapamil)
ACE inhibitors
Block conversion of angiotensin I to angiotensin II. (angiotensin II is responsible for vasoconstriction and liberating aldosterone). Inhibiting vasoconstriction and decreasing the effects of aldosterone results in a reduction of blood pressure (lisinopril, fosinopril, enalapril, captopril, ramipril).
Angiotensin II receptor blockers (ARBs)
Block effects of angiotensin II through antagonism of angiotensin II receptors leading to decreasing vasoconstriction and aldosterone secretion (losartan, valsartan, olmesartan, telmisartan).
Beta blockers
Block beta-adrenergic receptors resulting in a decrease in myocardial contractility, decrease in renin production, and relaxation of smooth muscles (metoprolol, atenolol, esmolol, carvedilol, labetalol)
Thiazide diuretics
Block reabsorption of NaCl in the distal convoluted tubule of the nephron leading to a contracted intravascular volume (hydrochlorothiazide, chlorthalidone).
Vasodilators
Work by decreasing vascular smooth muscle tone (hydralazine, sodium nitroprusside)
Alpha-2 adrenergic agonist
Works on central adrenergic receptors leading to decreased norepinephrine release (clonidine)
Direct renin inhibitor
Prevents renal release of renin with subsequent decrease in angiotensin II production (aliskiren)
What is hypertensive urgency
BP >180/120 with no signs/symptoms of end organ dysfunction
Refer to physician
How is hypotension treated intraoperatively
Ephedrine and phenylephrine. Be cautious of reflex bradycardia with phenylephrine usage.
Patients taking these medications are more prone to anesthesia-induced hypotension
ACE inhibitors and ARBs
AHA recommendation of epinephrine dose for “cardiac” patients
0.04mg of epinephrine(40 ug)
What is a hypertensive crisis?
BP 180/120 with signs/symptoms of myocardial ischemia, bradycardia, hypertensive encephalopathy, dyspnea, chest pain, confusion, nausea/vomiting, headache, seizures, and pulmonary edema.
Treatment is gradual reduction of BP to not lead to hypotension and subsequent myocardial ischemia and cerebrovascular ischemia.
What is atherosclerosis?
Pathophysiology
Hardening of the arteries due to lipid accumulation within the arterial wall.
Damage to endothelium
Lipoproteins traverse intima and leukocytes are recruited via chemotaxis
Macrophages imbibe LDL to form foam cells
Smooth muscle cells of media layer secrete exctracellular matrix that traps the lipoprotein and gives bulk to the lesion.
Matrix gives rise to fibrous cap. As lesion increases in size, fibrous cap thins. Rupturing of the fibrous cap exposes thrombotic lipid core, which may lead to ACS.
What is metabolic syndrome?
Cluster of HTN, hyperlipidemia, insulin resistance, and abdominal obesity
What is ischemic heart disease (IHD)?
Disease process secondary to stenotic coronary arteries that leads to ischemic sequelae from a myocardial oxygen supply and demand imbalance.
What is stable angina?
Transient chest discomfort due to a fixed atheromatous plaque secondary to a myocardial oxygen supply and demand imbalance.
- Dyspnea on exertion
- Retrosternal chest pain that may radiate to arm or jaw
- “Pressure” on chest
- Symptoms appear when vessel is at least 70% stenotic and cease with rest
Diagnostic workup angina
EKG may show ST depression or T wave inversion.
Stress testing to assess cardiac reserve.
Pharmacologic testing with dipyridamole thallium in persons unable to exercise.
Echocardiogram used to assess wall function, EF, and valvular function.
Coronary angiography is used to assess stenotic coronary arteries (gold standard).
What is acute coronary syndrome (ACS)?
Disease processes along a continuum secondary to a ruptured atherosclerotic plaque with subsequent formation of a thrombus within the coronary vessel.
What is unstable angina?
Occurs secondary to a coronary thrombus that is partially occlusive. Patients have chest pain that is not relieved by rest. Can see signs of ischemic changes on an EKG with negative cardiac enzymes.
Non-ST segment elevation MI vs. ST segment elevation MI
Non-STEMI: due to a partially occlusive thrombus that results in a subendocardial infarction.
STEMI: occlusive thrombus that results in a transmural infarct
Nitrates
cause venodilation which decreases preload (determinant of wall stress) and dilates coronary arteries.
How are beta blockers and calcium channel blockers used to treat ischemic heart disease?
Decrease oxygen demand by decreasing HR and contractility
Treatment of MI
Morphine (analgesia, anxiolysis)
Oxygen (increases O2 supply to myocardium)
Nitrates (improve coronary flow)
Aspirin (decrease platelet aggregation)
Beta-blockers: decrease myocardial oxygen demand
Transfer to hospital for PCI with stent deployment or fibrinolytic therapy if hospital does not have interventional cardiology capabilities.
What is congestive heart failure (CHF)?
Condition characterized by the inability of the heart to pump enough blood to meet the metabolic demands of the body