A 23-year-old man comes to the emergency department with an open wound on his right hand. He states that he got into a bar fight about an hour ago. He appears heavily intoxicated and does not remember the whole situation, but he does recall lying on the ground in front of the bar after the fight. He does not recall any history of injuries but does remember a tetanus shot he received 6 years ago. His temperature is 37°C (98.6°F), pulse is 77/min, and blood pressure is 132/78 mm Hg. Examination shows a soft, nontender abdomen. His joints have no bony deformities and display full range of motion. There is a 4-cm (1.6-in) lesion on his hand with the skin attached only on the ulnar side. The wound, which appears to be partly covered with soil and dirt, is irrigated and debrided by the hospital staff. Minimal erythema and no purulence is observed in the area surrounding the wound. What is the most appropriate next step in management?

Application of moist sterile dressing + tetanus vaccine

Apposition of wound edges under tension + rifampin

Surgical treatment with skin flap + ciprofloxacin

Surgical treatment with skin graft + tetanus vaccine

Tension-free apposition of wound edges + sterile dressing

A 58-year-old man is brought to the emergency department by his family because of severe upper back pain, which he describes as ripping. The pain started suddenly 1 hour ago while he was watching television. He has hypertension for 13 years, but he is not compliant with his medications. He denies the use of nicotine, alcohol or illicit drugs. His temperature is 36.5°C (97.7°F), the heart rate is 110/min and the blood pressure is 182/81 mm Hg in the right arm and 155/71 mm Hg in the left arm. CT scan of the chest shows an intimal flap limited to the descending aorta. Intravenous opioid analgesia is started. Which of the following is the best next step in the management of this patient condition?

Emergency surgical intervention

Oral metoprolol and/or enalapril

A 64-year-old woman has progressively worsening abdominal pain 5 hours after an open valve replacement with cardiopulmonary bypass. The pain is crampy and associated with an urge to defecate. The patient reports having had 2 bloody bowel movements in the last hour. Her operation was complicated by significant intraoperative blood loss, which prolonged the operation and necessitated 2 transfusions of red blood cells. She has hypercholesterolemia and type 2 diabetes mellitus. The patient received prophylactic perioperative antibiotics and opioid pain management during recovery. Her temperature is 37.9°C (98.9°F), pulse is 95/min, and blood pressure is 115/69 mm Hg. Examination shows a soft abdomen with mild tenderness to palpation in the left quadrants but no rebound tenderness or guarding. Bowel sounds are decreased. Rectal examination shows blood on the examining finger. Which of the following is the most likely underlying cause of this patient's symptoms?

Decreased blood flow to the splenic flexure

Embolization of superior mesenteric artery

Atherosclerotic narrowing of the intestinal vessels

Small outpouchings in the sigmoid wall

Infection with Clostridioides difficile

A 58-year-old man presents to the emergency department for evaluation of intermittent chest pain over the past 6 months. His history reveals that he has had moderate exertional dyspnea and 2 episodes of syncope while working at his factory job. These episodes of syncope were witnessed by others and lasted roughly 30 seconds. The patient states that he did not have any seizure activity. His vital signs include: blood pressure 121/89 mm Hg, heart rate 89/min, temperature 37.0°C (98.6°F), and respiratory rate 16/min. Physical examination reveals a crescendo-decrescendo systolic murmur in the right second intercostal area. An electrocardiogram is performed, which shows left ventricular hypertrophy. Which of the following is the best next step for this patient?

Computed tomography (CT) chest scan without contrast

Cardiac chamber catheterization

Transesophageal echocardiography

A 67-year-old man presents to the emergency department with abdominal pain that started 1 hour ago. The patient has a past medical history of diabetes and hypertension as well as a 40 pack-year smoking history. His blood pressure is 107/58 mmHg, pulse is 130/min, respirations are 23/min, and oxygen saturation is 98% on room air. An abdominal ultrasound demonstrates focal dilation of the aorta with peri-aortic fluid. Which of the following is the best next step in management?

Serial annual abdominal ultrasounds

Counsel the patient in smoking cessation

Urgent surgery within the next day

A 72-year-old woman comes to the physician for follow-up care. One year ago, she was diagnosed with a 3.8-cm infrarenal aortic aneurysm found incidentally on abdominal ultrasound. She has no complaints. She has hypertension, type 2 diabetes mellitus, and COPD. Current medications include hydrochlorothiazide, lisinopril, glyburide, and an albuterol inhaler. She has smoked a pack of cigarettes daily for 45 years. Her temperature is 37°C (98.6°F), pulse is 90/min, respirations are 12/min, and blood pressure is 145/85 mm Hg. Examination shows a faint abdominal bruit on auscultation. Ultrasonography of the abdomen shows a 4.9-cm saccular dilation of the infrarenal aorta. Which of the following is the most appropriate next step in management?

Elective endovascular aneurysm repair

Adjustment of cardiovascular risk factors and follow-up ultrasound in 12 months

Adjustment of cardiovascular risk factors and follow-up ultrasound in 6 months

Adjustment of cardiovascular risk factors and follow-up CT in 6 months

Aortic surgery basics for USMLE Step 1: High-Yield Surgery Lessons

🛣️ Anatomy - The Body's Superhighway

Anatomy of the Aorta with Segments and Major Branches

Aortic Segments:
- Root: Aortic valve, sinuses of Valsalva, coronary ostia.
- Ascending: Root to brachiocephalic artery.
- Arch: Gives off brachiocephalic, L. common carotid, L. subclavian arteries. 📌 "BCS" mnemonic.
- Descending: Thoracic (to diaphragm) & Abdominal (to iliac bifurcation).
Wall Layers (Inside → Out):
- Intima: Endothelium.
- Media: Elastin & smooth muscle.
- Adventitia: Vasa vasorum & nerves.

⭐ The vasa vasorum supplies the outer aortic wall. Its disruption (e.g., tertiary syphilis) can cause medial necrosis, leading to thoracic aortic aneurysms.

💔 Pathology - Leaks, Bulges, & Tears

Aortic Aneurysm: Localized dilation >1.5x normal diameter.
- True: Involves all 3 layers (e.g., Atherosclerotic, Marfan).
- Pseudo (False): Contained rupture; wall defect (e.g., trauma, iatrogenic).
- Rupture risk ↑ with radius (Law of Laplace: $T \propto P \times r$).
Aortic Dissection: Intimal tear creates a false lumen. Primary risk: HTN. Presents with tearing chest/back pain.

⭐ Aortic root dissection/rupture is the most common cause of death in untreated Marfan syndrome due to fibrillin-1 gene defects.

Aortic Dissection Progression

🔎 Radiology - Spotting the Trouble

CXR: Initial test. Key finding: widened mediastinum (>8 cm). Can show pleural effusion (hemothorax).
CTA (CT Angiography): Definitive diagnostic test for acute aortic syndromes and pre-op planning. Identifies intimal flap, hematoma, and branch involvement.
TEE: Bedside choice for unstable patients. Excellent for ascending aorta, aortic valve, and detecting tamponade.
MRA: Alternative to CTA; avoids radiation. Used for chronic dissection follow-up.

⭐ CTA is the gold standard for diagnosing acute aortic dissection, offering rapid, detailed anatomical mapping crucial for surgical decisions.

🔪 Management - Scalpels and Stents

Open Surgical Repair:
- The traditional standard. Involves direct replacement of the diseased aortic segment with a synthetic (Dacron) graft.
- Preferred for: Young patients, connective tissue disease (e.g., Marfan), or anatomy unsuitable for endovascular options.
- ⚠️ High morbidity: Requires large incision and aortic cross-clamping.
Endovascular Repair (EVAR/TEVAR):
- Minimally invasive placement of a stent-graft via femoral artery access.
- Preferred for: Older, high-risk surgical candidates with suitable anatomy (adequate proximal/distal "landing zones").

AAA management: EVAR vs. open repair decision pathway

⭐ Endoleak: Persistent blood flow into the aneurysm sac outside the stent-graft post-EVAR/TEVAR. The most common complication, requires lifelong surveillance as it indicates treatment failure and risk of rupture.

💥 Complications - The Aftermath

Neurologic: Stroke (embolic); Spinal Cord Ischemia (esp. thoracoabdominal repair).
Renal: Acute Kidney Injury (AKI) from hypoperfusion, atheroemboli, or contrast. Monitor creatinine.
Cardiac: Myocardial infarction, arrhythmias (post-op A-fib is common).
Gastrointestinal: Mesenteric ischemia (SMA territory) → severe pain, acidosis; high mortality.
Vascular/Graft: Hemorrhage, thrombosis, infection, pseudoaneurysm, endoleak (EVAR-specific).

⭐ Anterior Spinal Artery Syndrome: A feared complication of descending aortic surgery. Presents with bilateral flaccid paralysis and loss of pain/temperature sensation below the injury. Dorsal columns (proprioception, vibration) are spared.

⚡ Biggest Takeaways

Type A aortic dissection (ascending) is a surgical emergency; Type B (descending) is managed medically first with strict BP control.

CT Angiography (CTA) is the gold standard for diagnosing both aortic dissection and aneurysms.

Repair an abdominal aortic aneurysm (AAA) if >5.5 cm, rapidly expanding, or symptomatic.

Screen men aged 65-75 with a smoking history for AAA using ultrasound.

Anterior spinal artery syndrome is a feared complication of thoracoabdominal aortic repair, causing paraplegia.

Patients with Marfan syndrome require prophylactic aortic surgery at smaller diameters due to high dissection risk.

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