A 64-year-old man presents to his physician for a scheduled follow-up visit. He has chronic left-sided heart failure with systolic dysfunction. His current regular medications include captopril and digoxin, which were started after his last episode of symptomatic heart failure approximately 3 months ago. His last episode of heart failure was accompanied by atrial fibrillation, which followed an alcohol binge over a weekend. Since then he stopped drinking. He reports that he has no current symptoms at rest and is able to perform regular physical exercise without limitation. On physical examination, mild bipedal edema is noted. The physician suggested to him that he should discontinue digoxin and continue captopril and scheduled him for the next follow-up visit. Which of the following statements best justifies the suggestion made by the physician?

Digoxin is useful to treat atrial fibrillation, but does not benefit patients with systolic dysfunction who are in sinus rhythm.

Long-term digoxin therapy produces significant survival benefits in patients with heart failure, but at the cost of increased heart failure-related admissions.

Both captopril and digoxin are likely to improve the long-term survival of the patient with heart failure, but digoxin has more severe side effects.

Captopril is likely to improve the long-term survival of the patient with heart failure, unlike digoxin.

Digoxin does not benefit patients with left-sided heart failure in the absence of atrial fibrillation.

A 35-year-old woman presents as a new patient to a primary care physician. She hasn't seen a doctor in many years and came in for a routine check-up. She has no specific complaints, although she has occasional shortness of breath with mild activity. On physical exam, her vital signs are as follows: HR 80, BP 110/70, RR 14. On auscultation, her lungs are clear with equal breath sounds bilaterally. When listening over the precordium, the physician hears a mid-systolic click followed by a late systolic murmur that is loudest over the apex. Valsalva increases the murmur. Which of the following is NOT a possible complication of this patient's underlying problem?

Bleeding from acquired von Willebrand disease

A 66-year-old female with hypertension and a recent history of acute ST-elevation myocardial infarction (STEMI) 6 days previous, treated with percutaneous transluminal angioplasty (PTA), presents with sudden onset chest pain, shortness of breath, diaphoresis, and syncope. Vitals are temperature 37°C (98.6°F), blood pressure 80/50 mm Hg, pulse 125/min, respirations 12/min, and oxygen saturation 92% on room air. On physical examination, the patient is pale and unresponsive. Cardiac exam reveals tachycardia and a pronounced holosystolic murmur loudest at the apex and radiates to the back. Lungs are clear to auscultation. Chest X-ray shows cardiomegaly with clear lung fields. ECG is significant for ST elevations in the precordial leads (V2-V4) and low-voltage QRS complexes. Emergency transthoracic echocardiography shows a left ventricular wall motion abnormality along with a significant pericardial effusion. The patient is intubated, and aggressive fluid resuscitation is initiated. What is the next best step in management?

Immediate transfer to the operating room

Immediate cardiac catheterization

Intra-aortic balloon counterpulsation

Administer dobutamine 5-10 mcg/kg/min IV

A 29-year-old man is brought to the emergency room 6 hours after the onset of severe epigastric pain and vomiting. His heart rate is 110/min and blood pressure is 98/72 mm Hg. He is diagnosed with acute pancreatitis, and fluid resuscitation with normal saline is initiated. Which of the following is the most likely immediate effect of fluid resuscitation in this patient?

Increase in myocardial oxygen demand

Increase in plasma oncotic pressure

Increase in glomerular filtration fraction

Increase in volume of distribution

A 28-year-old male presents to his primary care physician with complaints of intermittent abdominal pain and alternating bouts of constipation and diarrhea. His medical chart is not significant for any past medical problems or prior surgeries. He is not prescribed any current medications. Which of the following questions would be the most useful next question in eliciting further history from this patient?

"Can you tell me more about the symptoms you have been experiencing?"

"Does the diarrhea typically precede the constipation, or vice-versa?"

"Is the diarrhea foul-smelling?"

"Please rate your abdominal pain on a scale of 1-10, with 10 being the worst pain of your life"

"Are the symptoms worse in the morning or at night?"

A 70-year-old man with severe ischemic cardiomyopathy (EF 25%) has recurrent ventricular tachycardia despite optimal medical therapy and ICD placement. Cardiac MRI shows a large anteroseptal scar with viable myocardium in the lateral and inferior walls. He has three-vessel coronary disease. His daughter is advocating for heart transplantation, but he has multiple comorbidities including obesity (BMI 37) and active tobacco use. Evaluate the management priority and rationale.

CABG with surgical ventricular reconstruction and continued medical optimization

Left ventricular assist device as destination therapy

Catheter ablation of VT with continued ICD monitoring

Cardiac resynchronization therapy upgrade and medication adjustment

List for heart transplantation immediately given severe cardiomyopathy

A 49-year-old woman with myasthenia gravis undergoes CT chest showing a 5 cm anterior mediastinal mass with irregular borders. Biopsy confirms thymoma (WHO type B2). She has well-controlled myasthenic symptoms on pyridostigmine. Staging shows no distant metastases, but the mass abuts the pericardium without clear invasion. Evaluate the optimal treatment approach.

Thymectomy with possible en bloc pericardial resection, followed by adjuvant radiation

Increase immunosuppression then delayed surgery in 6 months

Radiation therapy alone to preserve myasthenia control

Immediate thymectomy followed by observation

Neoadjuvant chemotherapy, then thymectomy and adjuvant radiation

A 58-year-old man with coronary artery disease requires CABG. Preoperative angiography shows 90% left main stenosis, 95% proximal LAD stenosis, 80% circumflex stenosis, and chronic total occlusion of the RCA with collaterals. He has diabetes, renal insufficiency (Cr 2.1), and previous stroke. Evaluate the optimal grafting strategy to maximize long-term patency and outcomes.

LIMA to LAD, radial artery to circumflex, vein graft to RCA

Bilateral internal mammary arteries with supplemental vein grafts

Off-pump CABG with sequential vein grafts only

All saphenous vein grafts to minimize operative time

LIMA to LAD, saphenous vein grafts to remaining vessels

Mechanical circulatory support devices for USMLE Step 2 CK: High-Yield Surgery Lessons

⚙️ The Heart's Helpers

Mechanical Circulatory Support (MCS) devices are used for cardiogenic shock or advanced heart failure. They unload the ventricle and improve end-organ perfusion.

Intra-Aortic Balloon Pump (IABP): Counter-pulsation device. Inflates during diastole to ↑ coronary perfusion; deflates during systole to ↓ afterload.
Percutaneous VADs (e.g., Impella): Catheter-based axial flow pump placed across the aortic valve. Directly unloads the LV by pumping blood to the aorta.
Ventricular Assist Device (VAD): Surgically implanted pump. Used as a bridge-to-transplant or as destination therapy.
VA-ECMO: Provides full cardiopulmonary support, bypassing the heart and lungs.

⭐ Continuous-flow LVADs can cause acquired von Willebrand syndrome due to shear stress on vWF multimers, leading to a high risk of GI bleeding from arteriovenous malformations (AVMs).

💔 Pathophysiology - When the Pump Fails

Cardiogenic shock is profound cardiac pump failure, causing end-organ hypoperfusion despite adequate intravascular volume. The fundamental equation is $CO = HR \times SV$.

Primary Insult: ↓ Myocardial contractility → ↓ Stroke Volume (SV) & Cardiac Output (CO).
Maladaptive Compensation:
- Baroreceptor reflex → ↑ Sympathetic tone & ↑ SVR (afterload).
- RAAS activation → ↑ volume (preload).
Vicious Cycle: ↑ Afterload & ↑ Preload further strain the failing ventricle, increasing myocardial O₂ demand and worsening ischemia.

⭐ In cardiogenic shock, the heart operates on the flat/descending part of the Frank-Starling curve; increasing preload (fluids) worsens pulmonary congestion without improving CO.

Frank-Starling curves: normal vs. failing heart

⚙️ Management: Choosing the Right Device

Selection is multifactorial, guided by:

Goal of Therapy: Bridge to Recovery (BTR), Transplant (BTT), Candidacy (BTC), or Destination Therapy (DT).
Required Duration: Short-term (<30 days) vs. Long-term (months-years).
Hemodynamic Severity: INTERMACS profile (1=crashing, 7=stable).
Patient Factors: RV function, ambulation potential, end-organ function, anticoagulation tolerance.

⭐ INTERMACS profiles are key. Profile 1 ("Crash and Burn") requires immediate, temporary support (e.g., ECMO). Stable, inotrope-dependent patients (Profile 4, "Resting Symptoms") are prime candidates for durable LVADs as Bridge to Transplant (BTT) or Destination Therapy (DT).

⚠️ Complications - When Good Tech Goes Bad

📌 Mnemonic: BITH-R (Bleeding, Infection, Thrombosis, Hemolysis, Right Heart Failure).

Bleeding: Most common.
- GI Bleeding: Due to acquired von Willebrand Syndrome (AVWS) from shear stress on vWF multimers & angiodysplasia from non-pulsatile flow.
Thrombosis:
- Pump Thrombosis: Suspect with ↑ power consumption, hemolysis.
- Stroke/TIA: Embolic events.
Infection:
- Driveline infection is most frequent; can lead to sepsis.
Hemolysis: Mechanical RBC destruction.
- Labs: ↑ LDH, ↑ plasma-free Hb, ↓ haptoglobin.
Right Heart Failure: Common after LVAD placement; RV fails to handle increased preload.

⭐ Continuous-flow LVADs cause loss of pulsatility, leading to arteriovenous malformations (AVMs) in the GI tract, a major cause of recurrent bleeding.

⚡ Biggest Takeaways

IABP: Inflates in diastole to ↑ coronary perfusion; deflates in systole to ↓ afterload. Contraindicated in aortic regurgitation.

LVADs: A bridge-to-transplant or destination therapy. High risk of thrombosis, stroke, and GI bleeding (acquired vWD).

ECMO: V-A for cardiopulmonary support (cardiogenic shock); V-V for isolated respiratory failure (ARDS).

Impella: Percutaneous pump directly unloads the LV across the aortic valve, reducing myocardial oxygen demand.

Universal risks: thrombosis, bleeding (anticoagulation-related), infection, and hemolysis.

Continue reading on Oncourse

CONTINUE READING — FREE

or get the app

App Store|Google Play