Cardiac Risk in Non-cardiac Surgery — MCQs
What is the correct sequence of medication administration for pre-operative prophylaxis in pheochromocytoma?
Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
Which of the following drugs need not be stopped before surgery?
A lady presents with grade 3 dyspnea, severe mitral stenosis, and atrial fibrillation, with an increased ventricular rate and a clot in the left atrium. Which of the following should not be done?
Which one of the following is not a component of THORACOSCORE?
A 55-year-old male, known smoker, complains of calf pain while walking. He experiences calf pain while walking but can continue walking with effort. Which grade of claudication does this patient fall under?
Which of the following is not used in controlling heart rate intraoperatively?
Blood loss during major surgery is best estimated by:
Patient shows ST depression, troponin rise 6h post-surgery. Next best step is:
A patient posted for Lap Cholecystectomy had drug eluting stent placed two years back. Patient has no symptoms since then. Which of the following set of investigation should be done in this patient?
Cardiac Risk in Non-cardiac Surgery Indian Medical PG Practice Questions and MCQs
Question 1: What is the correct sequence of medication administration for pre-operative prophylaxis in pheochromocytoma?
- A. Beta blockade followed by alpha blockade
- B. Simultaneous alpha and beta blockade
- C. Alpha blockade followed by beta blockade (Correct Answer)
- D. Alpha blockade only
Explanation: ***Alpha blockade followed by beta blockade*** - **Alpha blockade** should always be initiated first to control **hypertension** and prevent a **hypertensive crisis** during surgery. This is critical because pheochromocytoma causes excessive catecholamine release, leading to profound vasoconstriction. - **Beta blockade** is then added only after adequate alpha blockade has been achieved to control **tachycardia** and arrhythmias, preventing **unopposed alpha-adrenergic stimulation** which could paradoxically worsen hypertension. *Simultaneous alpha and beta blockade* - Administering both simultaneously is dangerous because **beta blockade** can mask the effects of inadequate alpha blockade. - This can lead to **unopposed alpha-adrenergic stimulation** after beta blockade, causing severe **vasoconstriction** and hypertensive crisis. *Beta blockade followed by alpha blockade* - Initiating with **beta blockade** without prior **alpha blockade** is absolutely contraindicated in pheochromocytoma. - This can lead to severe and potentially fatal **hypertension** due to **unopposed alpha-adrenergic stimulation** as beta blockade prevents vasodilation. *Alpha blockade only* - While essential for initial management, **alpha blockade alone** might not fully control all symptoms, especially **tachycardia** and **arrhythmias** caused by high circulating catecholamine levels. - Adding a **beta blocker** after achieving adequate alpha blockade helps in controlling these cardiac effects, optimizing patient preparation for surgery.
Question 2: Most sensitive method of monitoring cardiovascular ischemia in the perioperative period is -
- A. NIBP
- B. ECG
- C. Pulse oximeter
- D. TEE (Correct Answer)
Explanation: ***TEE*** - **Transesophageal echocardiography (TEE)** is the most sensitive method for detecting perioperative myocardial ischemia because it can visualize **regional wall motion abnormalities** and changes in **ventricular function** much earlier than ECG. - **Ischemia** directly impairs the contractility of the affected myocardium, leading to subtle changes in wall motion that TEE can identify. *NIBP* - **Non-invasive blood pressure (NIBP)** monitoring can detect **hemodynamic changes** (like hypotension or hypertension) that may precede or accompany ischemia. - However, these changes are **non-specific** and occur relatively late, making NIBP a less sensitive indicator of early ischemia. *ECG* - **Electrocardiography (ECG)** monitors the electrical activity of the heart and can detect **ST-segment changes** indicative of ischemia. - While useful, ECG changes may appear later than wall motion abnormalities, and **silent ischemia** can be missed if the leads are not optimally placed or if the ischemia does not produce significant electrical changes. *Pulse oximeter* - A **pulse oximeter** measures **oxygen saturation** in the peripheral blood. - It is primarily used to assess **respiratory function** and tissue oxygenation, and it does not directly monitor myocardial ischemia or cardiac function.
Question 3: Which of the following drugs need not be stopped before surgery?
- A. High Dose Aspirin
- B. Metformin
- C. Digitalis (Correct Answer)
- D. Warfarin
Explanation: ***Digitalis*** - **Digitalis (digoxin)** is often continued through surgery, especially in patients with **heart failure** or **atrial fibrillation** to maintain cardiac function. - Its cessation could precipitate **cardiac decompensation** or arrhythmias, which are high-risk events during surgery. *High Dose Aspirin* - **High-dose aspirin** should generally be stopped before surgery due to its **antiplatelet effects**, increasing the risk of perioperative bleeding. - The duration of discontinuation depends on the type of surgery and individual patient risk. *Metformin* - **Metformin** should be stopped before surgery due to the risk of **lactic acidosis**, especially in situations involving **renal impairment** or hypoperfusion associated with surgery. - It's typically held on the day of surgery and for 24-48 hours post-operatively, depending on renal function. *Warfarin* - **Warfarin** is a strong oral anticoagulant that must be discontinued before most surgeries to prevent **excessive bleeding**. - It is typically stopped 5 days pre-op, and patients often receive **bridging therapy** with heparin, depending on their risk for thromboembolism.
Question 4: A lady presents with grade 3 dyspnea, severe mitral stenosis, and atrial fibrillation, with an increased ventricular rate and a clot in the left atrium. Which of the following should not be done?
- A. Rate control with diltiazem
- B. Warfarin therapy
- C. Open mitral commissurotomy and removal of clot
- D. Electrical cardioversion (Correct Answer)
Explanation: ***Electrical cardioversion*** - Due to the presence of a **left atrial clot**, electrical cardioversion is contraindicated as it carries a high risk of **systemic embolism** if the clot dislodges. - Cardioversion should only be considered after **anticoagulation** and confirmation that no left atrial clot is present, typically via transesophageal echocardiography (TEE). *Rate control with diltiazem* - **Diltiazem** is a calcium channel blocker commonly used for **rate control in atrial fibrillation** by slowing AV nodal conduction [1]. - While rate control is important in this patient, especially with severe mitral stenosis, it does not directly address the immediate high risk of **embolism** from the clot [2]. *Warfarin therapy* - **Warfarin** is indicated for **anticoagulation** to prevent further clot formation and reduce the risk of embolism in patients with atrial fibrillation and a documented left atrial clot [2]. - However, warfarin itself will not acutely resolve an existing clot or address the immediate hemodynamic issues, and it requires a therapeutic INR before interventions like cardioversion can be considered. *Open mitral commissurotomy and removal of clot* - **Open mitral commissurotomy** is a surgical procedure to address severe mitral stenosis and can simultaneously allow for direct removal of a **left atrial clot**. - While this is a definitive treatment for both the stenosis and the clot, it is an invasive surgical option and not something to "not be done" if indicated, although risks need to be weighed.
Question 5: Which one of the following is not a component of THORACOSCORE?
- A. Performance status
- B. Complication of surgery (Correct Answer)
- C. Priority of surgery
- D. ASA grading
Explanation: ***Complication of surgery*** - THORACOSCORE is a **risk prediction model** for thoracic surgery used to estimate the *probability of mortality and significant morbidity*, but it does not account for the complications of surgery itself as a component. - The score uses **pre-operative patient characteristics** and co-morbidities to predict outcomes, not post-operative events. *Performance status* - **Performance status**, such as the **ECOG scale**, is a crucial component of THORACOSCORE, reflecting the patient's general health and functional capacity prior to surgery. - A lower performance status (indicating poorer functional ability) increases the predicted risk in THORACOSCORE. *Priority of surgery* - The **priority of surgery** (e.g., elective, urgent, emergency) is an important factor in THORACOSCORE, as emergency procedures generally carry a higher risk. - This variable helps to capture the urgency and associated physiological stress on the patient at the time of presentation for surgery. *ASA grading* - The **American Society of Anesthesiologists (ASA) physical status classification system** is a component of THORACOSCORE, assessing the patient's overall health status and anesthetic risk. - A higher ASA grade (indicating more severe systemic disease) contributes to a higher predicted risk in the THORACOSCORE model.
Question 6: A 55-year-old male, known smoker, complains of calf pain while walking. He experiences calf pain while walking but can continue walking with effort. Which grade of claudication does this patient fall under?
- A. Grade I (Mild claudication)
- B. Grade II (Moderate claudication) (Correct Answer)
- C. Grade III (Severe claudication)
- D. Grade IV (Ischemic rest pain)
Explanation: ***Grade II (Moderate claudication)*** - **Grade II claudication** is characterized by **intermittent claudication** where the patient experiences pain while walking but can **continue walking with effort**. - This level of claudication reflects a moderate degree of peripheral arterial disease, where blood flow is sufficiently compromised to cause pain with exertion but not severe enough to force immediate cessation of activity. - The patient in this scenario can continue ambulation despite discomfort, which is the defining feature of this grade. *Grade I (Mild claudication)* - **Grade I claudication** involves discomfort or pain that the patient can **tolerate without significantly altering their gait or pace**. - In this stage, the pain is minimal, and the patient may perceive it as a dull ache or mild fatigue rather than true pain. - Walking can continue without significant effort or limitation. *Grade III (Severe claudication)* - **Grade III claudication** is marked by pain that is **severe enough to stop the patient from walking within a short distance** (typically less than 200 meters). - The pain forces the patient to rest and recover before they can resume walking. - This represents significant functional limitation in daily activities. *Grade IV (Ischemic rest pain)* - **Grade IV**, also known as **critical limb ischemia**, involves **pain even at rest**, especially in the feet or toes, often worsening at night when the limb is elevated. - This stage indicates severe arterial obstruction and is frequently associated with **ulcers, non-healing wounds, or gangrene**. - This represents advanced peripheral arterial disease requiring urgent intervention. **Note:** This grading system is a simplified clinical classification. The standard medical classifications for peripheral arterial disease are the **Fontaine classification** (Stages I-IV) and **Rutherford classification** (Categories 0-6).
Question 7: Which of the following is not used in controlling heart rate intraoperatively?
- A. Verapamil
- B. Esmolol
- C. Propanolol/Metoprolol
- D. Procainamide (Correct Answer)
Explanation: ***Procainamide*** - While an antiarrhythmic, **procainamide** is primarily used for the treatment of various *atrial* and *ventricular arrhythmias* and *Wolff-Parkinson-White syndrome*, not for heart rate control alone. - Its mechanism involves blocking sodium channels and some potassium channels, affecting myocardial excitability and conduction. *Verapamil* - **Verapamil** is a **non-dihydropyridine calcium channel blocker** frequently used intraoperatively to **slow heart rate** by acting on the sinoatrial and atrioventricular nodes. - It is effective in treating *supraventricular tachycardias* (SVT) and controlling ventricular rate in *atrial fibrillation* or *flutter*. *Esmolol* - **Esmolol** is a **short-acting, cardioselective beta-1 adrenergic blocker** that is often administered intraoperatively due to its rapid onset and offset of action. - It is used to quickly **decrease heart rate** and blood pressure, particularly in response to surgical stress or in cases of *supraventricular tachycardia*. *Propranolol/Metoprolol* - **Propranolol** (non-selective) and **Metoprolol** (cardioselective) are **beta-adrenergic blockers** commonly used to **reduce heart rate** and myocardial oxygen demand. - They are effective in managing *tachycardia*, *hypertension*, and preventing *myocardial ischemia* during surgery.
Question 8: Blood loss during major surgery is best estimated by:
- A. Transesophageal USG Doppler
- B. Visual assessment
- C. Suction bottles (Correct Answer)
- D. Cardiac output by thermodilution
Explanation: ***Suction bottles*** - Measuring the volume of fluid collected in **suction bottles** (after subtracting irrigating fluid) provides a direct and quantifiable estimate of blood loss. - This method is widely used in surgery due to its **simplicity and relative accuracy** for assessing blood collected from the surgical field. *Transesophageal USG Doppler* - This technique primarily assesses **cardiac function** and **blood flow dynamics**, not directly quantifying blood loss. - While it can indicate hypovolemia, it doesn't provide a precise measurement of the volume of blood lost. *Visual assessment* - **Visual estimation** of blood loss by surgical staff is notoriously inaccurate and can lead to significant underestimation or overestimation. - It is highly subjective and depends on factors like lighting, the color of the blood-soaked materials, and individual experience. *Cardiac output by thermodilution* - **Thermodilution** is used to measure cardiac output, which can reflect hemodynamic status and help guide fluid resuscitation. - It does not directly quantify the amount of blood lost but rather assesses the **body's response** to blood loss.
Question 9: Patient shows ST depression, troponin rise 6h post-surgery. Next best step is:
- A. 12-lead ECG
- B. Echocardiogram
- C. Cardiology consult (Correct Answer)
- D. Start heparin
Explanation: ***Cardiology consult*** - A cardiology consult is the most appropriate next step given the presence of **ST depression** and a **troponin rise** post-surgery, indicating a likely myocardial infarction (MI). - This allows for prompt comprehensive evaluation, risk stratification, and initiation of specialized cardiac management by an expert. *12-lead ECG* - While a 12-lead ECG is an important diagnostic tool, the patient's existing **ST depression** suggests it has already been performed or noted. - A repeat ECG might be useful for tracking changes, but it doesn't replace the need for expert cardiac evaluation and management. *Echocardiogram* - An echocardiogram can assess **cardiac function**, wall motion abnormalities, and valvular issues, which are relevant in MI. - However, it's a diagnostic test that should be ordered and interpreted in the context of a broader cardiac workup, which a cardiologist can best coordinate. *Start heparin* - **Heparin** is an anticoagulant that may be part of the management for an MI, especially in certain types or for prevention of clot extension. - However, initiating anticoagulation should be done after a thorough assessment of the patient's cardiac status, bleeding risk post-surgery, and in consultation with cardiology, rather than as the immediate next best step.
Question 10: A patient posted for Lap Cholecystectomy had drug eluting stent placed two years back. Patient has no symptoms since then. Which of the following set of investigation should be done in this patient?
- A. Coronary angiography, Thallium scan
- B. ECG, CBC, Coronary angiography
- C. ECG, CBC, Stress echocardiography (Correct Answer)
- D. ECG, CBC, Stress echocardiography, coronary angiography
Explanation: **ECG, CBC, Stress echocardiography** - A patient with a **drug-eluting stent (DES)** placed two years prior, who is now asymptomatic, typically requires a **non-invasive cardiac assessment** before surgery. [1] - **Stress echocardiography** is an appropriate investigation to assess for inducible ischemia in an asymptomatic patient with a history of DES, especially when determining readiness for non-cardiac surgery. [1] *Coronary angiography, Thallium scan* - **Coronary angiography** is an invasive procedure and is generally not indicated for asymptomatic patients two years post-DES unless there are new symptoms or high-risk findings on non-invasive tests. [2] - A **Thallium scan** (myocardial perfusion scintigraphy) is a valid stress test, but **stress echocardiography** provides similar information regarding ischemia and ventricular function without radiation exposure. [1] *ECG, CBC, Coronary angiography* - While **ECG** and **CBC** are standard preoperative tests, **coronary angiography** is an invasive procedure and is not the first-line investigation for an asymptomatic patient two years post-DES without other indications. [2] - The patient's asymptomatic status suggests that invasive testing is not immediately warranted for surgical clearance. *ECG, CBC, Stress echocardiography, coronary angiography* - Performing both **stress echocardiography** and **coronary angiography** in an asymptomatic patient two years after DES placement is **redundant** and subjects the patient to an unnecessary invasive procedure. [1], [2] - The results of a non-invasive stress test like stress echocardiography would guide the need for any further invasive intervention.
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