A 62-year-old man comes to the emergency department for severe, acute right leg pain. The patient's symptoms began suddenly 4 hours ago, while he was reading the newspaper. He has poorly-controlled hypertension and osteoarthritis. He has smoked one pack of cigarettes daily for 31 years. Current medications include lisinopril, metoprolol succinate, and ibuprofen. He appears to be in severe pain and is clutching his right leg. His temperature is 37.4°C (99.3°F), pulse is 102/min and irregularly irregular, respirations are 19/min, and blood pressure is 152/94 mm Hg. The right leg is cool to the touch, with decreased femoral, popliteal, posterior tibial, and dorsalis pedis pulses. There is moderate weakness and decreased sensation in the right leg. An ECG shows absent P waves and a variable R-R interval. Right leg Doppler study shows inaudible arterial signal and audible venous signal. Angiography shows 90% occlusion of the right common femoral artery. In addition to initiating heparin therapy, which of the following is the most appropriate next step in management?

Surgical bypass of the affected vessel

Percutaneous transluminal angioplasty

Amputation of the affected limb

A 57-year-old man is brought to the emergency department by his family because of several episodes of vomiting of blood in the past 24 hours. He has a history of alcoholic cirrhosis and is being treated for ascites with diuretics and for encephalopathy with lactulose. His vital signs include a temperature of 36.9°C (98.4°F), pulse of 85/min, and blood pressure of 80/52 mm Hg. On examination, he is confused and unable to give a complete history. He is noted to have jaundice, splenomegaly, and multiple spider angiomas over his chest. Which of the following is the best initial management of this patient?

Combined vasoactive and endoscopic therapy

A 62-year-old man comes to the physician because of a 5-day history of swelling in his left arm. Two months ago, he was diagnosed with a deep venous thrombosis in the left calf. He has had a 7-kg (15-lb) weight loss in the last 3 months. He has smoked 1 pack of cigarettes daily for the past 25 years. His only medication is warfarin. Physical examination shows warm edema of the left forearm with overlying erythema and a tender, palpable cord-like structure along the medial arm. His lungs are clear to auscultation bilaterally. Duplex sonography shows thrombosis of the left basilic and external jugular veins. Which of the following is the most appropriate next step to confirm the underlying diagnosis?

Transesophageal echocardiography

Serum antiphospholipid antibody level

A 29-year-old woman, gravida 1, para 1, comes to the physician for the evaluation of a painful mass in her left breast for several days. She has no fevers or chills. She has not noticed any changes in the right breast. She has no history of serious illness. Her last menstrual period was 3 weeks ago. She appears anxious. Her temperature is 37°C (98.6°F), pulse is 80/min, respirations are 13/min, and blood pressure is 130/75 mm Hg. Examination shows a palpable, mobile, tender mass in the left upper quadrant of the breast. Ultrasound shows a 1.75-cm, well-circumscribed anechoic mass with posterior acoustic enhancement. The patient says that she is very concerned that she may have breast cancer and wishes further diagnostic testing. Which of the following is the most appropriate next step in the management of this patient?

Reassurance and clinical follow-up

A 27-year-old man is witnessed falling off his bicycle. The patient rode his bicycle into a curb and hit his face against a rail. The patient did not lose consciousness and is ambulatory at the scene. There is blood in the patient's mouth and one of the patient's teeth is found on the sidewalk. The patient is transferred to the local emergency department. Which of the following is the best method to transport this patient's tooth?

Wrapped in gauze soaked in normal saline

A 58-year-old man presents to the Emergency Department after 3 hours of intense suprapubic pain associated with inability to urinate for the past day or two. His medical history is relevant for benign prostatic hyperplasia (BPH) that has been under treatment with prazosin and tadalafil. Upon admission, he is found to have a blood pressure of 180/100 mm Hg, a pulse of 80/min, a respiratory rate of 23/min, and a temperature of 36.5°C (97.7°F). He weighs 84 kg (185.1 lb) and is 175 cm (5 ft 7 in) tall. Physical exam, he has suprapubic tenderness. A bladder scan reveals 700 ml of urine. A Foley catheter is inserted and the urine is drained. Initial laboratory tests and their follow up 8 hours after admission are shown below. Admission 8 hours after admission Serum potassium 4.2 mmol/L Serum potassium 4.0 mmol/L Serum sodium 140 mmol/L Serum sodium 142 mmol/L Serum chloride 102 mmol/L Serum chloride 110 mmol/L Serum creatinine 1.4 mg/dL Serum creatinine 1.6 mg/dL Serum blood urea nitrogen 64 mg/dL Serum blood urea nitrogen 62 mg/dL Urine output 250 mL Urine output 260 mL A senior attending suggests a consultation with Nephrology. Which of the following best justifies this suggestion?

Estimated glomerular filtration rate (eGFR)

Serum blood urea nitrogen (BUN)

A 48-year-old woman is brought to the emergency department because of a 1-hour history of sudden-onset headache associated with nausea and vomiting. The patient reports she was sitting at her desk when the headache began. The headache is global and radiates to her neck. She has hypertension. She has smoked one pack of cigarettes daily for the last 10 years. She drinks alcohol occasionally. Her father had a stroke at the age 58 years. Current medications include hydrochlorothiazide. She is in severe distress. She is alert and oriented to person, place, and time. Her temperature is 38.2°C (100.8°F), pulse is 89/min, respirations are 19/min, and blood pressure is 150/90 mm Hg. Cardiopulmonary examination shows no abnormalities. Cranial nerves II–XII are intact. She has no focal motor or sensory deficits. She flexes her hips and knees when her neck is flexed while lying in a supine position. A CT scan of the head is shown. Which of the following is the most appropriate intervention?

Administer intravenous alteplase

Administer intravenous vancomycin and ceftriaxone

Perform decompressive craniectomy

Interventional radiology procedures for USMLE Step 1: High-Yield Anatomy Lessons

Intro to IR - Needles, Wires, & Access

Access Core: Needles → Wires → Catheters/Sheaths.
Needles: For initial puncture.
- Types: Beveled (Francine), Cutting (Chiba), Trocar (sharp stylet).
Guidewires: Rail for catheter passage.
- J-tip: Atraumatic, avoids intimal injury.
- Glidewire: Hydrophilic coating for tight lesions.
Catheters: Sized in French units ($1\text{ Fr} = 1/3\text{ mm}$).

Seldinger Technique Steps

⭐ The Seldinger technique is the cornerstone of gaining safe vascular and non-vascular access.

Vascular Procedures - Plumbing & Blockages

Angioplasty & Stenting:
- Mechanically widens stenotic vessels (e.g., atherosclerosis, fibromuscular dysplasia).
- Procedure: A balloon is inflated within the vessel, often followed by placing a metal stent to maintain patency.
- Key Indications: Peripheral artery disease (PAD), renal artery stenosis (RAS), coronary artery disease (CAD).
Catheter-Directed Thrombolysis & Thrombectomy:
- Targets acute blockages from clots.
- Thrombolysis: Infuses a fibrinolytic agent (e.g., tPA) directly into the thrombus.
- Thrombectomy: Aspirates or mechanically destroys the clot.
- Indications: Acute limb ischemia, massive pulmonary embolism (PE), extensive deep vein thrombosis (DVT).
Embolization:
- Deliberate occlusion of a blood vessel to stop flow.
- Agents: Coils, particles, glue.
- Uses: Control active bleeding (trauma, GI bleed), treat tumors (chemoembolization), uterine fibroid embolization (UFE).

Angiogram: Coil embolization of bleeding visceral artery

⭐ TIPS Procedure: The Transjugular Intrahepatic Portosystemic Shunt (TIPS) creates a low-resistance channel between the portal vein and a hepatic vein. This decompresses the portal system but can precipitate or worsen hepatic encephalopathy by shunting ammonia-rich blood past the liver.

Non-Vascular Work - Biopsies, Drains, & Ablations

Image-Guided Biopsy
- Types: Core needle (histology) vs. Fine-Needle Aspiration/FNA (cytology).
- Guidance: Ultrasound (real-time, no radiation), CT (superior resolution), or MRI.
- Indications: Characterize masses (e.g., liver, lung, kidney, thyroid).
- Contraindications: Uncorrectable coagulopathy, unsafe access path.
Percutaneous Drainage
- Purpose: Evacuate fluid collections (e.g., abscesses, seromas, bilomas).
- Technique: Seldinger technique is standard for catheter placement.
- Management: Monitor output quality/quantity; flush to maintain patency.

⭐ In abscess drainage, successful therapy is marked by decreasing, less purulent output (e.g., purulent → serosanguinous).

Tumor Ablation
- Goal: Destroy unresectable tumors (HCC, RCC, lung mets).
- Modalities:
  - Radiofrequency (RFA): Frictional heat.
  - Microwave (MWA): Faster, larger zones, resists heat sink.
  - Cryoablation: Freeze/thaw cycles induce cell death.

CT-guided core needle biopsy of liver lesion

IR Safety - Contrast & Complications

Iodinated Contrast:
- Contrast-Induced Nephropathy (CIN): Risk ↑ if eGFR < 30. Prevent with robust IV hydration.
- Allergic-like Reactions: Premedicate patients with a prior reaction using corticosteroids.
Gadolinium Contrast:
- Nephrogenic Systemic Fibrosis (NSF): High risk in severe renal dysfunction (eGFR < 30).

⭐ Hold Metformin for 48h post-contrast if eGFR < 30 or in acute kidney injury (AKI). This prevents potential for lactic acidosis.

High‑Yield Points - ⚡ Biggest Takeaways

Transjugular Intrahepatic Portosystemic Shunt (TIPS) treats refractory ascites or variceal bleeding but risks worsening hepatic encephalopathy.

Catheter-directed embolization is a primary treatment for acute hemorrhage, such as in GI bleeds or pelvic trauma.

Percutaneous drainage is preferred over open surgery for most abdominal abscesses.

Percutaneous nephrostomy provides emergent decompression for an obstructed urinary system, especially with infection.

IVC filters are for pulmonary embolism prophylaxis when anticoagulation is contraindicated.

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