History of Myocardial Infarction

8.3 History of Myocardial Infarction

Section I: Clinical Scenario and Dental Considerations

Clinical Scenario

A 63‐year‐old male presents for an urgent dental appointment complaining of discomfort from his upper right front tooth (#11). This tooth has become increasingly painful since the filling was lost 2 days ago.

Medical History

  • Myocardial infarction (MI) 5 years earlier
  • Arterial hypertension (without target organ impairment)
  • Dyslipidaemia
  • Type 2 diabetes (poorly controlled)
  • Severe chronic obstructive pulmonary disease (GOLD stage III)
  • Obstructive sleep apnoea syndrome (receiving continuous positive airway pressure therapy [CPAP])
  • Morbid obesity (BMI= 46 kg/m2)


  • Acetylsalicylic acid
  • Nebivolol
  • Amlodipine
  • Tiotropium bromide
  • Fluticasone
  • Metformin
  • Simvastatin

Dental History

  • Last visit to a dentist ~6 years ago; did not return for regular care as he could not cope when the dental chair was reclined due to difficulty breathing/increasing dental anxiety
  • Prior to this, reports visiting the dentist regularly, with several fillings undertaken
  • Used to wear a removable lower denture prosthesis but can no longer tolerate it
  • Brushes his teeth irregularly

Social History

  • Single; no children
  • Lives with his 87‐year‐old mother
  • On a minimal disability allowance
  • Walks with difficulty
  • Came to the dental clinic in taxi
  • Frequently cannot leave his home because of fatigue and/or dyspnoea
  • Smokes 10 cigarettes/day (although he has tried to quit the habit)
  • Alcohol: <7 units a week

Oral Examination

  • Poor oral hygiene
  • #11 tender on palpation
  • Caries in #11, #12 and #33
  • Missing teeth #14, #15, #24, #25, #33–37 and #45–47
  • Grade 1 mobility of #31 and #41

Radiological Examination

  • Orthopantomogram undertaken (Figure 8.3.1)
  • Significant alveolar bone loss in the mandibular incisors
  • Root canal fillings and intraradicular posts in #13, #27 and #44
  • Root canal filling and dentine pin in #32
  • Fillings with secondary caries in #21, #22 and #44

Structured Learning

  1. You determine that #11 is non‐vital. The patient does not want to lose the tooth and requests root canal treatment. What may compromise the success of this treatment option?
    Photo depicts orthopantomogram demonstrating loss of multiple teeth and deterioration of dental health (M/L).

    Figure 8.3.1 Orthopantomogram demonstrating loss of multiple teeth and deterioration of dental health.

    • Patient may not be able to cope with multiple or longer appointments due to his multiple comorbidities and fatigue
    • Access may be compromised (i.e. unable to recline the patient fully due to dyspnoea/chronic obstructive pulmonary disease, further airway compromise in relation to morbid obesity), presence of obesity‐related decubitus ulcers
    • Adverse effects of the antihypertensive drugs (orthostatic hypotension)
    • Co‐operation may be limited due to dental anxiety
    • May not be able to tolerate rubber dam due to airflow restriction and dental anxiety
    • Underlying diabetes may reduce likelihood of success of endodontic treatment (impaired immunity/wound healing)
    • Potentially increased bleeding due to medication and underlying hypertension
    • Oral hygiene poor and irregular dental attendance
    • #11 poor restorability; horizontal bone loss
  2. Following a discussion of the factors which may compromise the outcome of endodontic treatment of #11, the patient still wishes to proceed. What additional factors are considered important in assessing the risk of managing this patient?
    • Social
      • Reduced mobility
      • Dependence on adapted taxis
      • Limited financial means
      • No suitable escort
      • Dental anxiety
    • Medical
      • History of MI and higher risk of a repeat episode (multiple risk factors including smoking, raised BMI, hypertension, diabetes)
      • Risk of a hypertensive crisis (see Chapter 8.1)
      • Bleeding tendency due to antithrombotic agents and arterial hypertension
      • Severe limitation of air flow due to advanced chronic obstructive pulmonary disease (see Chapter 9.1)
      • Risk of hypoglycaemia/hyperglycaemia, delayed wound healing and infections due to diabetes mellitus (see Chapter 5.1)
      • Diabetes mellitus also increases the risk of a silent MI (diabetic neuropathy)
      • Morbid obesity and related commodities; may require a bariatric dental chair/facilities as most standard dental chairs have a weight limit of ~20 stone/127 kg (see Chapter 16.4)
      • Drug interactions and adverse effects
    • Dental
      • Multiple missing teeth
      • Unable to wear the previous lower denture
      • Poor prognosis for the remaining teeth (e.g. #43)
      • Poor oral hygiene and irregular toothbrushing
      • Irregular dental attendance
  3. Why does dental treatment potentially increase the risk of a further MI?
    • Dental treatment‐related pain and stress increase the amount of catecholamine released in blood
    • This results in elevated heart rate and blood pressure; these in turn can reduce the oxygen demand–supply balance in the myocardium and induce myocardial ischaemia
    • In addition, elevated blood catecholamine levels may induce platelet aggregation and coronary spasms, leading to MI
    • Conversely, blood pressure reduction due to neurogenic shock or syncope triggered during dental treatment reduces coronary blood flow, increasing the risk of thrombotic occlusion in stenotic sections of the coronary arteries
  4. Should this patient be seen for treatment in a hospital or primary care setting?
    • A hospital setting is preferred
    • Although the MI event was 5 years earlier, this patient has multiple comorbidities which increase his risk, including:
      • Severe chronic obstructive pulmonary disease
      • Uncontrolled hypertension
      • Uncontrolled diabetes
      • Morbid obesity
      • Additional risk factor of dental anxiety which may further compromise the existing cardiac and respiratory conditions
  5. The patient’s care is transferred to a hospital dental service. A medical review is sought prior to scheduling dental treatment as the patient complains of non‐specific symptoms of increasing fatigue and dizziness. An ECG confirms that the patient has had a silent MI. What impact does this have on planned dental treatment?
    • Previously it was suggested that only conservative emergency dental treatment procedures should be undertaken during the first 6 months after a MI
    • This advice was based on historical evidence which indicated that for patients with histories of MI within 3 months, the incidence of reinfarction due to general anaesthesia or surgery was as high as 37%; the reinfarction rate decreased to 18% over a 3 month period from 3 to 6 months after MI onset, and to approximately 6% thereafter
    • Management of patients at risk of MI has significantly improved over the last 20 years
    • It has been recognised that although the incidence of reinfarction remains relatively high after major surgical interventions, such as thoracic surgery and vascular surgery, it is considerably lower after minor surgeries under local anaesthesia (e.g. dental extraction and pulpectomy), if the correct support is in place
    • Supportive measures include anxiety management, premedication with nitrates, minimum use of a local anaesthetic with vasoconstrictor, and monitoring of blood pressure, heart rate and ECG in a hospital environment
    • Furthermore, lack of satisfactory dental treatment to eliminate significant dental infection could aggravate myocardial ischaemia, with the pain itself acting as an inducer
    • Severe toothache also interferes with sleep and food intake, causing further physiological and psychological stress
    • Hence the general consensus is that dental treatment should be delayed for 6 weeks
    • However, for this patient, there are additional risk factors in relation to smoking, uncontrolled diabetes and hypertension, in addition to morbid obesity; close liaison with the medical team to address these issues should be in place to reduce the overall risk
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Nov 6, 2022 | Posted by in Implantology | Comments Off on History of Myocardial Infarction

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