Angina
Clinical Syndrome
Myoacrdial ischemia
Precordial discomfort
Precipitated by exertion
Relieved by rest or sublingual Nitroglycerin
Radiation: Pain secondary to Myocardial ischenia or injury can radiate along medial aspect of left arm, to jaw , shoulders and epigastrium. Pain of Ureteral stones can radiate down to genitals. Pain of dissecting aneurysm radiates to back.
Different organs or anatomical locations.
Cardiovascular: Angina
Acute myocardial infraction
Pericarditis
Aortic dissectionGastrointestinal: Reflux esophagitis
Esophageal spasm
Esophageal rupturePulmonary: Pneumothroax
Pleuritis/pneumonia
Pulmonary embolus/infarctionMusculoskeletal: Traumatic injury
Costochondritis
Herpes zosterSomatization: Anxiety
Differential diagnosis
Angina:
Mostly felt beneath Sternum
Vague ache to crushing sensation
Radiates to left shoulder, inside left arm, into throat, jaws, epigastrium
Triggered by physical activity, cold air
Usually persists no more than few minutes (5-10 minuts)
Discomfort relieved by rest and Nitroglycerine
Acute myocardial infarction:
Crushing chest pain with or without radiation.
Lasts longer >20 minutes
Not relieved by rest or Nitroglycerine
Diaphoresis, nausea or vomiting
ECG changes
Cardiac enzymes results
Reflux esophagitis:
Esophageal spasm may be severe and centered in the chest although it may also bore to the back.
This pain could also be relieved by nitroglycerin
Worse in supine position
Worse following meals
relieved by antacids or acid blockers
Somatization: One of the most common office complaints is a primary care setting is chest "pain" or discomfort. The complaint often reflects somatization. A point should be made that not all pain is organic; therefore, the physician should pursue psychosocial stresses which may be the initiator of this problem.
Pericarditis. Precardiac, sharp, persistent. Worse in recumbent position Relieved by sitting.
Dissecting aorta. Sharp stabbing pain radiating to back. Asymmetry of pulses.
Chest wall Lesions
Musculo-skeletal injury:
Muscular skeletal pain often is localized along with point tenderness.
Sometimes it mimics pleuritic pain during inspiration.
Pneumothorax: Pain is sudden in onset, localized, sharp, worse on deep breathing and coughing. Associated with shortness of breath.
Pleuritis/pneumonia Pain is sudden in onset, localized, sharp, worse on deep breathing and coughing. Associated with productive cough, fever and chills.
Coronary arterial system.
Right and Left main coronary arteries.
There is some collateral circulation but they mostly behave like end arteries.
Regulation of blood flow to myocardium
Physiology of coronary flow
Increased myocardial activity requires more blood flow ( exercise, LV hypertrophy)
Direct from ventriclar chamber to myocardium. (small contribution)
Patho-physiology of Myocardial ischemia
Critical coronary artery obstruction (>70%)
Atherosclerosis
Spasm (Idiopathic, Cocaine)
Increased cardiac work
Calcific Aortic stenosis
Hypertrophic subaortic stenosis
Myocardial O2 demand exceeds the ability of the coronary arteries to supply oxygenated blood.
Coronary sinus blood pH falls/Cellular K loss occurs/EKG abnormalities appear
Ventricular performance deteriorates/LV diastolic pressure rises
Hypoxic metabolites/Discomfort
"The presence of atherosclerosis is not the same as the risk the disease presents. More people die
with atherosclerosis than die of it! "
Risk factors
Hypertension
Diabetes Mellitus
Hypercholesterolemia
Cigarette smoking
Family history of ischemic heart disease
HDL:
Good cholesterol.
Facilitates "reverse cholesterol transport" which helps clear the body of cholesterol
LDL:
Bad cholesterol when it exceeds normal levels.
Most atherogenic lipoprotein
Delivers cholesterol to peripheral tissues cells
Reults in clearance of a low-affinity "scavenger" pathway trigggering cascade of events leading to the development of foam cells
Diagnostic strategy
Diagnosis based primarily on history of characteristic pain
Reversible ischemic ECG changes ( ST segment depression, decreased R-wave height, intraventricular or bundle branch conduction disturbances, ventricular extra systoles)
Characteristic relief of discomfort with sub-lingual Nitroglycerin
Exercise stress ECG testing:
Response of ECG to graded exercise
Ischemic response supports Angina
With chest pain specificity 70%: sensitivity 90% in men
Negative test is a reliable indicator of no disease.
Coronary angiography
Documents the extent of anatomic coronary artery occlusion
Obstruction is physiologically significant when the luminal diameter is reduced >70%
Supplemental testing
We need to consider Exercise test and Coronary angiogram
It would be reasonable to obtain an exercise test and, depending on the result of that test, proceed with a cardiac catheterization.
One could easily argue, however, given the multiple risk factors and the high prior probability of coronary artery disease, that a negative exercise test may well be considered a false negative and one would go ahead with a Coronary Angiogram anyway. If that is one reasoning, then the exercise test would be a waste of time and money.
Drug therapy
Strategy (Revisit Pathophysiology to plan a therapeutic option)
Widen this frame for better visualization
Decrease Myocardial Oxygen demand/Coronary artery vasodilatation:
Sublingual nitroglycerine
Organic nitrates are excellent drugs for the treatment of stable angina. The
organic nitrates (R-O-NO2) combine with cysteine (R-SH) in the vessel wall to form a
nitrosothiol that releases nitric oxide (NO). The organic nitrates decrease ventricular
wall stress (oxygen demand) by reducing both preload and after load {wall stress = (P x r)/
(2 x wall thickness)} This results from a primary action on venous capacitance vessels
with a more minor effect on arterioles. Organic nitrates may also exert favorable effects
on oxygen supply. The reduced ventricular pressure during both diastole and systole will
decrease extra vascular coronary resistance (compressive forces). Organic nitrates also
dilate collateral vessels and will cause a small dilation of stenotic coronary arteries
when the stenosis is eccentric.
Dramatic relief within 1.5 to 3 minutes
Dose may be repeated after 5 minutes three times if there is no relief
Patient should carry the tablets always
Drug looses potency/ prescribe small amounts frequently
Long-acting nitrates
If sublingual nitroglycerine worked well but Mr. Solomon wanted something that
prevented his attacks then you could consider switching to a nitroglycerine patch, or
isosorbide dinitrate. Continuous nitrate therapy is not recommended due to the depletion
of cysteine in the vascular smooth muscle and the development of tolerance. A nitrate-free
interval of at least 8 hours is recommended between repeated doses.
Protection against Myocardial Ischemia
Beta-blockers and or calcium channel blockers.
If organic nitrate therapy alone was inadequate to control Mr. Solomons angina, then the combination of an organic nitrate and beta-blocker or an organic nitrate with a calcium channel antagonist (verapamil, diltiazem, long acting dihydrophyridine derivative) would provide greater protection against ischemia. Triple therapy consisting of an organic nitrate, beta-blocker and calcium channel blocker might also be considered. The short acting dihydropyridine derivatives (nifedipine) have been shown to increase mortality in patients with coronary artery disease and should not be prescribed.
Beta-blockers block sympathetic stimulation of the heart (reduce Systolic pressure, heart rate, contractility, cardiac output) and reduce myocardial O2 demand.
Calcium channel blockers are vasodilators and are useful when angina is due to spasm or associated with Hypertension.
Alter risk factors
Smoking: Start smoking cessation programs
Hypertension: Anti-hypertensive medication to lower blood pressure (specific agents yet to be covered in the therapeutics lectures-defer)
Hypercholesterolemia: An HMG-CoA reductase inhibitor to lower cholesterol
HMG-CoA reductase inhibitors block the rate limiting enzyme for the synthesis of
cholesterol. Serum cholesterol levels fall not only from a reduced synthetic rate but from
an up-regulation of LDL receptors in hepatocytes and an increased rate of LDL catabolism
from the circulating pool. The HMG-CoA inhibitors (lovastatin, simvastatin,
pravastatin),
have been shown in clinical trials to reduce the rate of progression of coronary
artherosclerotic lesion and to increase the frequency of regression. These agents have
also been shown to reduce the risk of death due to coronary artery disease and risk of
nonfatal myocardial infarction. The goal of this therapy (combined with dietary
restrictions) is to reduce serum cholesterol to <190 mg/dL.
Prevent Coronary thrombosis: Aspirin
Since aspirin reduces the risk of heart attack (coronary thrombosis) in patients
with coronary artery disease there is a strong indication for daily aspirin (160 mg/day)
therapy. Aspirin causes irreversible inhibition of platelet cyclooxygenase, decreased
thromboxane A2 production and decreased platelet aggregation. Then aspirin is given as
prophylactic therapy to reduce the risk of intracoronary thrombosis and would probably
have little effect on Mr. Solomons angina.
Options we have to relieve mechanical obstruction of Coronary arteries
Angioplasty:
Involves insertion of a balloon tipped catheter into an artery at the site of partial obstruction
Inflation of the balloon can rupture the intima and media and dramatically dilate the obstruction
It is an alternative to bypass surgery in a patient with suitable anatomic lesions
Stents can be placed can be placed to reduce reocclusion
Coronary Artery Bypass Surgery
Venous graft
Internal mammary artery graft