Empty, Not Vasoplegic: Aortic Stenosis After Surgery

It's two in the morning. Your patient had an aortic valve replacement this afternoon — good ventricle, off bypass without a fuss — and the noradrenaline has crept up again. Your general intensive care instinct says work out why they're vasoplegic and turn the pressors up. In this specific patient, that instinct is wrong. Nine times out of ten they aren't vasoplegic. They're empty. In this episode Mike and Calum work through aortic stenosis and the problems it creates on the cardiac unit. This is the intensive care half; the cath lab half, on TAVI and sedation, is the next episode. Please note: the fluids and practice described are Wythenshawe-specific. Take the principles, and check your own guidelines. We start with why that patient is empty. Aortic stenosis is mechanically an outflow tract obstruction, so the ventricle hypertrophies against it — and this afternoon the surgeon fixed the obstruction, but the ventricle didn't get the memo. A thick, stiff, non-compliant ventricle is exquisitely preload-dependent, and reaching for the vasopressor instead of the fluid will have you chasing that patient all night. Expect to give five litres in twenty-four hours, expect them to be overloaded a few days later, and don't reach for albumin on day zero — because by the time it arrives, your patient is another litre behind. Then the disease itself. Why symptoms are the prognostic trigger — a one-year mortality of fifty percent from the moment they appear — and the murky world of low-gradient aortic stenosis, where the gradient depends on a ventricle that can still generate it. The sickest patients are precisely the ones the measurement fails on, underestimating severity and overestimating valve area. We cover the velocity ratio, which is dimensionless and sidesteps the problem, the four classes of severe aortic stenosis, dobutamine stress echo for pseudo-severe disease, and why gated CT with a calcium score has displaced echo as the most important scan for structural heart disease. We also cover the heart team and why anaesthetists and intensivists belong on it (we're generalists, and we're good at assessing risk — where once we were simply the brake at the end of the process), the causes of aortic stenosis, and what a right heart catheter actually tells you. Finally, two things that land on the reg overnight. Out-of-hospital cardiac arrest — where the principles are the same wherever the patient is, and the cardinal rule is not to prognosticate early, because the picture genuinely changes and the story matters as much as the tests. And pacing: AAI is fine after grafts but dangerous after valve surgery, VVI backup at 30–40 is your safety net, interrogate the box daily, restore community settings before discharge — and if a patient arrests, look at the pacing box before you open the chest. Chapters (00:00) Cold open — the pressors that keep climbing (01:20) Why the post-AVR ventricle is empty, not vasoplegic (03:10) Five litres in twenty-four hours (04:40) Why not albumin on day zero (06:00) AS pathophysiology, and why symptoms change everything (07:40) Low-gradient AS: when the gradient lies (09:20) The velocity ratio and the calcium score (11:00) The heart team, and why we're on it (12:40) Causes of AS, and the right heart catheter (14:00) Out-of-hospital arrest: don't prognosticate early (16:00) Pacing: AAI after grafts, VVI backup after valves (18:00) When TAVI patients come to ICU (19:10) Wrap-up Key takeaways The post-AVR patient with a hypertrophied ventricle is preload-dependent — when the pressure sags they're usually empty, not vasoplegic Five litres in 24 hours is normal here; expect overload and diuretics a few days later Don't use albumin on day-zero hearts — it arrives too late to help, and there's no evidence one fluid beats another Symptoms are the trigger in aortic stenosis: one-year mortality of 50% from the moment they appear In low-gradient disease the gradient lies — it underestimates severity and overestimates valve area The velocity ratio is dimensionless, so it sidesteps the geometric assumptions and the need for a high gradient Gated CT with a calcium score has displaced echo as the key scan in structural heart disease Anaesthetists and intensivists belong on the heart team because we're generalists and we assess risk Never prognosticate early after an out-of-hospital arrest — go multimodal, and weigh the story alongside the tests AAI is fine after grafts but dangerous after valve surgery; VVI backup at 30–40 is the safety net If a patient arrests on the unit, look at the pacing box first References / further reading Vahanian A et al. 2021 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J 2021 Otto CM et al. 2020 ACC/AHA Guideline for the Management of Patients With Valvular Heart Disease. Circulation 2021 Pibarot P, Dumesnil JG. Low-flow, low-gradient aortic stenosis with normal and depressed left ventricular ejection fraction. J Am Coll Cardiol 2012 Clavel MA et al. Aortic valve calcification by computed tomography in aortic stenosis. J Am Coll Cardiol 2013 Nolan JP et al. European Resuscitation Council and ESICM guidelines 2021: post-resuscitation care. Intensive Care Med 2021 Dankiewicz J et al. TTM2: hypothermia versus normothermia after cardiac arrest. NEJM 2021 Royal College of Anaesthetists. 7th National Audit Project (NAP7): perioperative cardiac arrest. 2023 Charlesworth M et al. Anaesthesia support for transcatheter heart valve interventions: a narrative review. Anaesthesia 2025 This podcast is for medical education for healthcare professionals. It is not clinical advice. Fluids, drugs and practice described reflect local Wythenshawe protocol at the time of recording — always follow your own centre's guidelines and current local policy.