Think Aorta: Hypertensive Emergencies and Dissection

A thirty-five-year-old with chest pain, a bit sweaty, a bit anxious, and a blood pressure that's frankly high. In a lot of departments that patient gets a troponin, a D-dimer, possibly a label of anxiety — and goes home. If that pain was an acute type A dissection, they are not going to get better.

In this episode Mike and Calum work through hypertension and the acute aortic syndromes as they actually present — the intensive care half of the topic. The theatre half, on deep hypothermic circulatory arrest, is the next episode.

Please note: the drugs and doses discussed are either local Wythenshawe practice or suggestions quoted from international guidance. Take the principles, and check your own guidelines and local policy for the numbers.

We start with a distinction people use interchangeably and shouldn't: emergency versus urgency. It hangs entirely on hypertension-mediated organ damage — acute damage to the heart, retina, brain, kidneys or large arteries — and the counterintuitive consequence is that severe hypertension without organ damage does not mandate emergency treatment. Meanwhile HMOD can occur at normal blood pressure readings, because the rate of change matters more than any threshold.

Then the disease itself. The syndromes that should raise your suspicion — Marfan, Turner, bicuspid aortic valve, Ehlers-Danlos — and the trap that these patients are usually not under surveillance, because nobody has ever diagnosed them. Stanford and DeBakey classification, roughly one percent mortality per hour for the first forty-eight hours, and the contrasting logic for a chronic aneurysm, where you watch and wait until 5.5 cm in the ascending aorta or 6.5 cm descending.

We're fair about why it gets missed, and honest about the consequence: treat it as an ACS or a PE and you anticoagulate a patient who was going to bleed anyway. What they need is a CT chest and a phone call to a cardiac centre.

Finally, the pharmacology done properly. Why heart rate matters as much as pressure — shear stress relates to dP/dt, so you're blunting the impulse, not just the number. Labetalol versus esmolol, the personalities and downsides of GTN, magnesium and hydralazine, and the two ways to hurt someone with treatment: overtreatment and overshoot, causing watershed infarction, mesenteric ischaemia and acute kidney injury. Plus the thing to do before any antihypertensive at all — treat the pain. We close with phaeochromocytoma (alpha blockade first, always) and PRES, the one that needs the scan as well as the clinical picture.

Chapters

• (00:00) Cold open — the chest pain that gets sent home
• (01:20) Emergency vs urgency: it's the organ damage, not the number
• (03:30) The syndromes — and why nobody has diagnosed them
• (05:30) Stanford, DeBakey, and one percent an hour
• (07:20) The chronic aneurysm: watch, or operate?
• (09:00) Why type A dissections get missed
• (10:40) Preoperative goals and anti-impulse therapy
• (12:30) The drugs and their personalities
• (14:20) Overtreatment, overshoot — and treating pain first
• (15:50) Phaeochromocytoma: alpha before beta, always
• (17:00) PRES — the one that needs the scan
• (18:00) Wrap-up

Key takeaways

• A hypertensive emergency is defined by acute hypertension-mediated organ damage, not by the number — and HMOD can occur at normal blood pressures
• Hypertensive urgency, without organ damage, does not mandate emergency treatment
• Patients presenting with dissection are often undiagnosed — it may be the first time anyone has looked at them properly
• Type A is any dissection involving the ascending aorta; roughly 1% mortality per hour for the first 48 hours
• Chronic aneurysm is different logic: surveillance, then operate above 5.5 cm ascending or 6.5 cm descending
• It gets missed as ACS, PE, acute abdomen or anxiety — and those patients arrive anticoagulated
• Treat pain first, then anti-impulse therapy: shear stress is about dP/dt, not just peak pressure
• Target systolic 100–120 and a rate of 60–70, using an infusion rather than boluses to avoid overshoot
• Alpha blockade before beta in phaeochromocytoma — beta blockade alone is contraindicated
• PRES is a clinical and radiological diagnosis, and can occur in normotensive patients

References / further reading

• Davies EA, Charlesworth M, Agarwal S. Hypertensive emergencies. BJA Education 2024
• Isselbacher EM et al. 2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease. Circulation2022
• Erbel R et al. 2014 ESC Guidelines on the diagnosis and treatment of aortic diseases. Eur Heart J 2014
• van den Born BJ et al. ESC Council on Hypertension position document on the management of hypertensive emergencies. Eur Heart J Cardiovasc Pharmacother 2019
• Williams B et al. 2018 ESC/ESH Guidelines for the management of arterial hypertension. Eur Heart J 2018
• Connor D, Boumphrey S. Perioperative care of phaeochromocytoma. BJA Education 2016
• Fischer M, Schmutzhard E. Posterior reversible encephalopathy syndrome. J Neurol 2017

This podcast is for medical education for healthcare professionals. It is not clinical advice. Drugs and doses discussed reflect local practice or quoted international guidance at the time of recording — always follow your own centre's guidelines and current local policy.