The definitions for levels of evidence (A-D) and classes of recommendation (I-III) are provided at the end of the "Major Recommendations" field.
Hypertension
- If blood pressure is high and there is time enough time before surgery to reduce it with proper medications, do so; Class I, Level of Evidence D.
- If blood pressure is high and there is not enough time before surgery to reduce it with proper medications, administer a cardioselective beta-1 receptor blocker with rapid onset (esmolol) to keep the blood pressure from rising during intubation. Clonidine can be used when esmolol is contraindicated; Class I, Level of Evidence C.
- The antihypertensive medication (including angiotensin converting enzyme [ACE] inhibitors) must be continued during the perioperative period, including on the day of the procedure. Class I, Level of Evidence D.
- If the patient's potassium level is low, intravenous administration of potassium is recommended; Class I, Level of Evidence D.
- The reintroduction of antihypertensive medication, preferably the one that the patient was using before surgery, should be done as soon as possible. Class I, Level of Evidence D.
- Volume management should be rigorous during the perioperative period. Class I, Level of Evidence C.
Congestive Heart Failure (CHF) Class I, Level of Evidence D
- Assessment of patients with CHF symptoms must focus on determining its etiology and the patients functional class (New York Heart Association [NYHA])
- Treatment must be optimized before surgery and patient must continue to take medications during the entire perioperative period (including the day of surgery)
- Anesthetic agents that depress myocardial contractility must be avoided in patients with CHF
- Volume management must be rigorous. Invasive monitoring can be useful during the intraoperative and early postoperative periods of patients with severely depressed cardiac function
- Careful evaluation of the fluid and electrolyte balance must be done
Valvular Heart Disease
- Patients with valvular heart disease should be referred to a cardiologist before surgery; Class I, Level of Evidence D.
- Patients with valvular lesion, especially aortic stenosis, with indication for corrective surgery, should have their heart disease corrected before being submitted to non-cardiac surgery whenever possible; Class I, Level of Evidence C.
- Control of blood volume and electrolytic disorders must be given special attention during the entire perioperative period; Class I, Level of Evidence D.
- When appropriate, prophylaxis of infective endocarditis should be done; Class I, Level of Evidence D.
- The level of anticoagulation must be well adjusted in order to avoid hard-to-control bleeding. The use of heparins should follow current guidelines; Class I, Level of Evidence C.
Cardiac Arrhythmias and Conduction Disorders
Cardiac Arrhythmias
Refer for Cardiologist Assessment
- Patients with symptoms that are associated with
- Low output or syncope, structural heart disease associated with compromised left ventricular systolic function and/or myocardial ischemia; Class I, Level of Evidence D.
- Tachyarrhythmia in patients with ventricular preexcitation syndrome with sudden onset and termination, without clinical findings or adequate treatment; Class I, Level of Evidence D.
- Tachyarrhythmias, regardless of structural heart disease, in patients with well-defined, frequent and recent symptoms of tachycardia episodes of sudden onset and termination; Class IIa, Level of Evidence D.
- Low output or syncope in elderly patients with a resting heart rate below 50 bpm; Class IIa, Level of Evidence D.
- In the absence of symptoms
- In patients with permanent atrial fibrillation to assess control of heart rhythm; Class IIa, Level of Evidence D.
- In patients with very frequent ventricular arrhythmias or repetitive ventricular arrhythmias associated with structural heart disease; Class IIa, Level of Evidence D.
Atrioventricular (AV) and Intraventricular Conduction Disorders
Refer for Cardiologist Assessment
- Patients with AV blocks
- Severe AV blocks: Type II second-degree AV block, 2:1 AV block, paroxysmal or permanent complete AV block or AV dissociation; Class I, Level of Evidence D.
- Mild AV block in the resting electrocardiogram (ECG) but with symptoms that suggest low output or syncope; Class IIa, Level of Evidence D.
- Intraventricular blocks
- Trifascicular block; Class IIa, Level of Evidence D.
- Bifascicular block in the resting electrocardiogram (ECG) but with symptoms that suggest low output or syncope; Class IIa, Level of Evidence D.
Implantable Pacemakers and Cardioverter-Defibrillators
In the Preoperative Period
- Determine if the patient uses a single or dual chamber pacemaker, resynchronizer, defibrillator or multiple prostheses; Class I, Level of Evidence D.
- Check the identification card, radiological identification number or hospital records to determine what type of device the patient is using; Class I, Level of Evidence D.
- Determine if the patient depends on the pacemaker by reviewing previous assessments, asking the patient if they had syncopes or dizziness before the implant or decreasing the timing of the device to the lowest rate and observing if an escape focus occurs and its stability; Class I, Level of Evidence D.
- Determine the function of the pacemaker. This requires a specific previous assessment of the device and adjusting the settings. If it is impossible to adjust its settings, check if there is an effective pacemaker pacing artifact (that generates pacing) in the ECG; Class IIb, Level of Evidence D.
In the Intraoperative Period
- All patients must be monitored by continuous ECG and plethysmography (or auscultation, pulse palpation or ultrasound) regardless of the type of anesthesia; Class I, Level of Evidence C.
- Electrocautery Class I, Level of Evidence D
- Continuous cardiac monitoring with ECG monitor and pulse oximetry (heart rhythm monitoring is possible even during electrocautery)
- Use bipolar electrocautery. If bipolar is not available, use monopolar electrocautery but place the grounding pad far from the pacemaker and make sure to use a conducting gel
- Ground the electrocautery device properly by connecting it to a good grounding wire
- Limit the use of the electrocautery probe as much as possible and to very short periods and always monitor the ECG or heart rate
- If bradycardia or tachycardia occur during electrocautery (because of electromagnetic interference), place a magnet over the pacemaker every time the electrocautery probe is used. Note that if the magnet is placed correctly, the pacemaker stimulates the heart with a fixed heart rate
- Avoid using arrhythmogenic agents during anesthesia (sympathicomimetic and/or atropine-like agents)
- Avoid volume overload and if possible, keep the patient in the slightly elevated reclined position
- Remind the patient to return to the pacemaker checkup clinic after the postoperative recovery period so that the original settings can be restored and the pacemaker reassessed.
- Radiofrequency ablation: place the grounding pads far from the generator and leads and do not allow the ablation catheter to touch the pacemaker's leads Class I, Level of Evidence C
- Lithotripsy (Drach, Weber, & Donovan, 1990): do not focus the lithotripsy beam toward the pacemaker and leads. Turn off atrial stimulation when using ECG-triggered lithotripsy; Class IIa, Level of Evidence D
- Cardioversion or defibrillation Class I, Level of Evidence D
- Internal cardioversion is preferred in patients with internal (implantable) cardioverter-defibrillator (ICD) since it uses less energy, biphasic pulse and internal safety resources of the device itself
- Prefer cardioverters that come with adhesive pads. Place them anteroposteriorly, according to the polarity informed by the manufacturer. Avoid the standard placement of the pads (between the base and tip of the heart – parallel to the leads) since the myocardium may be injured by the tip of the lead
- Attach the pads as far as possible from the generator and leads
- Use as little energy as possible. Modern cardioverters delivering biphasic shocks should be preferred
- Place a magnet over the generator of the pacemaker (not over that of the ICD because if a magnet remains over them for more than 30 seconds, it can disable the antitachycardia function). This attitude leads to two different responses: the sensing circuit of older pacemakers invariably shuts down when a magnet is placed over them and become asynchronous. Conversely, modern rate-responsive devices are programmable and can have different behaviours. Thus, placing a magnet over the generator does not necessarily protect the device during a cardioversion.
- Verify the sensing and pacing thresholds after the procedure. Consider reassessing the device in 24 hours and monitor the patient during this time.
In the Postoperative Period: Class I, Level of Evidence D
- Heart rate and rhythm must be continuously monitored during the postoperative period
- Cardioversion/defibrillation equipment and resources for cardiac stimulation must be available
- If the functions of the pacemaker were changed for surgery, reprogram it back to its usual settings as soon as possible
Organ Transplants
- Use non-invasive methods to determine if kidney and liver transplant candidates with risk factors for coronary artery disease have ischemic heart disease; Class IIa, Level of Evidence D.
- When revascularization is indicated for patients with coronary artery disease, it should precede transplant surgery; Class IIa, Level of Evidence D.
- Investigate if liver transplant candidates have pulmonary hypertension before submitting them to liver transplant; Class IIa, Level of Evidence D.
- Transplant indication must be reassessed if there is severe comorbidity with unfavorable short-term prognosis; Class I, Level of Evidence D.
Heart Disease and Pregnancy
Recommendations on Additional Tests (National Commission on Radiation Protection, 1987)
- Resting or dynamic ECG and Doppler echocardiogram do not pose any risk for mother or fetus; Class I, Level of Evidence D.
- Chest x-ray should not be used routinely during pregnancy; Class I, Level of Evidence C.
- Myocardial scintigraphy is not advised because the fetus can be exposed to ionizing radiation. If absolutely necessary, use technetium-99m and thalium-201 scintigraphy; Class IIb, Level of Evidence C.
- Galium-67 scintigraphy is always contraindicated during pregnancy; Class I, Level of Evidence C.
- When hemodynamic studies are needed, make sure to protect the abdomen; Class I, Level of Evidence C.
- Nuclear magnetic resonance is not contraindicated during pregnancy; Class I, Level of Evidence C.
Recommendations for Surgeries in Pregnant Women
- Delaying indication for surgery and surgery itself are the main causes for morbidity and mortality
- The second trimester of pregnancy is the safest for the mother and fetus
- Conventional surgical techniques should not be modified because of pregnancy
- Serial assessment of fluid and electrolyte balance and hematocrit and hemoglobin levels
- The pregnant uterus should not be allowed to compress the inferior vena cava during surgery
- An efficient analgesia prevents preterm birth
- Gastrointestinal decompression prevents emesis and aspiration
- Insure efficient pre-oxygenation before induction and intubation
- Prevent paralytic ileus
- Avoid using too much crystalloid solution in the intraoperative infusion
- Avoid using solutions containing glucose when delivery is imminent to reduce the risk of neonatal hypoglycemia
- Insert a Foley catheter to prevent build up of urine in the bladder
- Maintain the standard antibiotic therapy
- Pay special attention to lower limb edema as it increases the risks of phlebitis caused by prolonged inactivity and postoperative thromboembolism
- Do not encourage early ambulation to avoid preterm birth
- Administer vaginal progesterone to prevent premature labor (250 mg/day)
Recommendations for Prevention of Thromboembolism
- Heparin is the anticoagulant of choice for pregnant women as it does not cross the placental barrier and is not harmful to the fetus ("Brazilian consensus," 1999); Class I, Level of Evidence A.
- Although still controversial, preoperative anticoagulation therapy for high risk patients is 12 UI/kg/hour of nonfractionated intravenous (iv) heparin controlled by activated partial thromboplastin time (1.5 times the relation of partial thromboplastin times [PTTs]) or 1 mg/kg/day of low-molecular-weight heparin (enoxaparin) at 12-hour intervals. For patients at moderate risk, the recommendation is 10,000 UI of subcutaneous nonfractionated heparin at 12-hour intervals or subcutaneous low-molecular-weight heparin (enoxaparin) at 40 mg/day. Suspend the use of non-fractionated heparin 4 hours before surgery and low-molecular-weight heparin 18 hours before surgery, reintroducing them 6 hours after surgery ("Brazilian consensus," 1999). Class IIb, Level of Evidence C.
Dental Procedures
General Recommendations
- Patients on optimal medication therapy for heart disease can safely undergo dental procedures and do not require special care; Class I, Level of Evidence D.
- The use of anesthetics with vasoconstrictors should be avoided during acute phases of coronary events, cardiac arrhythmias with rapid ventricular response, hyperadrenergic states or left ventricular outflow obstruction; Class I, Level of Evidence D.
- Pacemakers and automatic internal cardiac defibrillators are not affected by high or low rotation speed drills, amalgam mixer, electrical pulp testing, laser, electric toothbrushes, endodontic ultrasound and radiography. There are specific recommendations for electrocautery (see Section F-I.3, Safe cardiac stimulation, in the original guideline document); Class I, Level of Evidence C.
Recommendations for Dental Procedures in Patients on Anticoagulation Therapy
- Warfarin should not be discontinued in patients who are not at high risk of bleeding; Class I, Level of Evidence D.
- Patients at high risk of bleeding should stop warfarin and the procedure could be done when international normalized ratio (INR) is under 1.5. If the patient is at high risk of thrombosis, heparin should be given thereafter, discontinued 4 hours before surgery, reintroduced as soon as possible after the procedure and maintained until INR >2.0; Class I, Level of Evidence D.
- Patients submitted to dental treatments that cause local bleeding can rinse their mouths with aqueous solutions of tranexamic or epsilon-aminocaproic acid without the need to discontinue anticoagulation therapy; Class I, Level of Evidence D.
Dental Procedures and Prevention of Infective Endocarditis
In this situation, the physician should consider the patient's susceptibility to infective endocarditis and the likelihood of the procedure contaminating the blood with a microorganism that is capable of causing infective endocarditis.
The dental procedures that are most likely to cause bacteremia are: subgingival placement of antibiotic fibers or strips, teeth extraction, dental implants or reimplants, endodontic and periodontal procedures, placement of orthodontic bands and procedures that cause significant bleeding. High-risk patients should always receive antibiotic prophylaxis when submitted to these procedures.
Definitions:
Levels of Evidence
- Sufficient evidence from multiple randomized trials or meta-analyses
- Limited evidence from single randomized trial or non-randomized studies
- Evidence only from case reports and series
- Expert opinion or standard of care
Class of Recommendation
Class I: Conditions for which there is evidence for and/or general agreement that the procedure/therapy is useful and effective
Class II: Conditions for which there is conflicting evidence and/or a divergence of opinion about the usefulness/efficacy of performing the procedure/therapy
Class IIa: Weight of evidence/opinion is in favor of usefulness/efficacy
Class IIb: Usefulness/efficacy is less well established by evidence/opinion
Class III: Conditions for which there is evidence for and/or general agreement that the procedure/therapy is not useful/effective and in some cases may be harmful
