Ischemic heart diseases

Oral surgery lecture 2

Ischemic heart diseases:
These diseases are mostly due to atherosclerosis of coronary artery. However, other factors may cause these diseases. These conditions usually occur due to imbalance in the oxygen supply and demand to the heart. Congestive heart failure could be the result of these conditions. There are two types of Angina pectoris either stable and unstable angina. Stable angina usually occurs after eating, exercise, and emotional stress and relieves after rest. There is no change in severity and duration of the attack. Unstable angina, on the other hand, occurs during rest and there is progression in the frequency of the attack. The more risky one is the unstable angina which might be followed by MI. The cause of atherosclerosis of coronary artery is still unknown; however, it could be associated with many factors such as hypertension, cigarette smoking, hyperlipidemia and diabetes mellitus.
Dentist should be aware of these diseases as stress and anxiety of dental procedure in addition to the vasoconstrictor in local anesthesia may trigger these conditions. Anti-coagulant or anti-platelets drugs may be prescribed for those patients which cause local bleeding during or after tooth extraction.
Sign and symptoms:
Substernal pain is the most common clinical presentation of angina pectoris. The pain could be radiated to the upper arms , lower jaw, palate and tongue. However, sometimes pain might be felt in the lower jaw or even upper arms and there is no central chest pain. Therefore, dentist should be aware of these conditions especially when there is no affected tooth/teeth present in the lower jaw.
Patient with angina pectoris could present with dyspnea and palpitation. Syncope (loss of consciousness) is another symptom which occurs due to decrease blood supply to the brain. Patient with myocardial infarction has the same clinical features of angina pectoris. However, chest pain in case of MI lasts 15 minutes and does not disappear after rest or medications; whereas in angina pectoris it takes about 3 minutes and relieves by rest or medications.
The signs of these diseases are few and associated with underlying cause. However, sometimes high blood pressure could be noticed. When the condition develops to congestive heart failure ,the signs could be more clearer such as distention of the neck veins, ascites and cyanosis
Medical management:
Nitroglycerin is commonly used in the treatment of angina pectoris. Nitroglycerin acts as vasodilators and hence increases blood supply to the heart. There are many forms of nitroglycerin either as sublingual tablets, oral tablets and dermal application. Beta-blockers, calcium channels blockers and Ranolazine can be used to manage ischemic heart disease as well. Anti-coagulants drugs could be prescribed for patient with ischemic heart disease to fasten blood flow and prevent its coagulation.



Dental management:
1- Patient with stable angina:
- Short morning appointment (avoid early morning).
- Dental chair should be in semi supine position.
- Check vital signs (blood pressure and pulse rate).
- An anti-anxiety protocol can be used 2-5 mg benzodiazepam at bed time and 1-2 hours before dental appointment. Nitrous oxide can be used as well.
- Patient should be advised to bring his/her own medication (nitroglycerin tablets) to dental clinic.
- Administer prophylactic nitroglycerine sublingually if dental procedure is expected to cause anginal attack.
- Plain anesthesia is more preferable; however, local anesthesia containing low adrenaline concentration 0.036 mg also can be used.
- Avoid gingival retraction cord containing epinephrine.
- Avoid anti-cholinergic drugs such as atropine and scopolamine. why?
- Aspirin which acts as anti-platelets could be prescribed to patient with angina pectoris. Daily taking of this drug may cause local bleeding during or after tooth extraction. However, such bleeding can be managed by local pressure.
- Pre-treatment checking of prothrombin time (12-13 seconds) and international normalized ratio(INR) for Patients on anti-coagulant drugs such as warfarin is mandatory. Prothrombin time should be two times less than the normal range and the INR <3. Reduction or cessation of these medications is the responsibility of patient s physician and not the dentist.
- If patient becomes fatigued or develops a change in pulse rate, discontinue and reschedule dental treatment .
- General anesthesia should be avoided.

2- Patient with unstable angina and mycardiac infarction of less than 6 months:
- Elective dental treatment should be postponed. However, urgent treatment should be done in dental care unite in the hospital. Consultation with patient s physician is mandatory to determine patient status.
- Pre-treatment at home:
a- Benzodiazepam 5-10 mg at bed time and 1 hour before surgical procedure.
b- Long acting dermal application of nitroglycerin.
- Pre-treatment at dental clinic:
a- Check vital signs.
b- Establish intravenous line.
c- Sublingual nitroglycerin to prevent anginal attack during dental treatment.
- During treatment:
a- Use nitrous oxide inhalation
b- Check pulse rate.
c- Benzodiazepam I.V should be given.
d- Prophylactic nitroglycerin sublingually.
e- Pain free procedure is very important. Use plain anesthesia or local anesthesia containing 0.036 mg adrenaline. Aspiration during giving anesthesia is important.

- If patient develops chest pain during dental procedure:
a- Stop dental procedure.
b- Give the patient one tablet nitroglycerine sublingually and wait for 5 minutes. If pain disappears either continue the procedure or postpone.
c- If pain does not disappear, check the vital signs; if the condition is stable give him another tablet sublingually and wait for another 5 minutes. If pain disappears either postpone or continue the procedure.
d- If pain does not disappear, then check the vital sign and if stable give him/her another sublingual tablet and wait for another 5 minutes. If pain disappears either postpone or continue. If pain does not disappear after 15 minutes of giving 3 tablets nitroglycerine, MI should be suspected and call the ambulance to transfer the patient to an emergency unite.