A 78-year-old female is admitted to ICU following aortic valve replacement for severe aortic stenosis.Her co-morbidities include ischaemic heart disease, peripheral vascular disease, hypertension, type 2 diabetes, emphysema and chronic kidney disease.
The operation was prolonged and difficult requiring repair of a right ventricular injury and emergency coronary artery bypass graft. The patient required adrenaline, noradrenaline and an intra-aortic balloon pump to separate from cardiopulmonary bypass.
At 4 hours post-operatively, she becomes progressively more hypotensive with increasing noradrenaline doses. List the potential causes for her shock state. (60% marks)
With respect to severe aortic stenosis, list the available alternatives to open valve replacement, with the respective advantages and disadvantages. (40% marks)
a)
Hypovolaemic • Bleeding
Cardiogenic • Acute MI • Graft obstruction • Diastolic dysfunction • RV failure • Pacing problem • Pulmonary hypertension
Distributive • Long bypass time • Occult sepsis (e.g. GI tract ischaemia) • Relative adrenal dysfunction • Nutritional deficiency
Obstructive • Pericardial tamponade • Left Ventricular Outflow Tract Obstruction • Prosthetic valve obstruction • Tension Pneumothorax (may be loculated due to previous surgery) • IABP failure / dyssynchrony/ malposition
Combination of above e.g. Aortic dissection
b)
Medical management only +/- palliation. Considered if prognosis of comorbidities is worse than natural history of AS. Avoids risks of surgery.
Medical management + balloon valvuloplasty. BAV may provide some symptomatic benefit albeit at the risk of complications from femoral vessels/ annular rupture. May also be useful diagnostically to see if dyspnoea improves.
TAVI – femoral access probably unlikely to be possible due to PVD, transapical or transoartic much higher risk but possible. Less invasive.
When you fix an aortic stenosis and it all goes well, frequently the patient will become hypertensive instead, which is clearly not what we see here. The table of potenstial reasons for shock is offered below, and it is similar to what is offered in the chapter about approaching the haemodynamically unstable post-pump patient.
Immediately recognisable on direct inspection
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Immediately recognisable on routine investigations
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Excluded by inspection and investigations
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In light of the offered scenario, several of these possibilities are more likely than the others:
Alternatives to open valve surgery can be listed, but the "advantages/disadvantages" question is an opening to a tabulated response. The best literature reference for this would probably be something like the UpToDate article, which gives you a choice between surgery, TAVI and conservative medical therapy. The 2016 article by Fattouch et al is also a good overview (and free).
Alternative |
Advantages |
Disadvantages |
Transfemoral |
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Transapical transcatheter aortic valve implantation |
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Balloon valvuloplasty |
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Conservative management |
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Frederick A. Hensley, Jr., M.D., Donald E. Martin, M.D., Glenn P. Gravlee, M.D. A Practical Approach to Cardiac Anaesthesia, 3rd ed. Sibylle A. Ruesch and Jerrold H. Levy. CHAPTER 9. The Postcardiopulmonary Bypass Period: A Systems Approach. 2003 by LIPPINCOTT WILLIAMS & WILKINS
André, Arthur C. St, and Anthony DelRossi. "Hemodynamic management of patients in the first 24 hours after cardiac surgery." Critical care medicine 33.9 (2005): 2082-2093.
Rodés-Cabau, Josep, et al. "Transcatheter aortic valve implantation for the treatment of severe symptomatic aortic stenosis in patients at very high or prohibitive surgical risk: acute and late outcomes of the multicenter Canadian experience." Journal of the American College of Cardiology 55.11 (2010): 1080-1090.
Alkhouli, Mohamad, et al. "Morbidity and Mortality Associated With Balloon Aortic Valvuloplasty." Circulation: Cardiovascular Interventions 10.5 (2017): e004481.
Linke, Axel, et al. "Treatment of aortic stenosis with a self-expanding transcatheter valve: the International Multi-centre ADVANCE Study."European heart journal 35.38 (2014): 2672-2684.
Schymik, Gerhard, et al. "Long-term results of transapical versus transfemoral TAVI in a real world population of 1000 patients with severe symptomatic aortic stenosis." Circulation: Cardiovascular Interventions 8.1 (2015): e000761.
Cao, Christopher, et al. "Systematic review and meta-analysis of transcatheter aortic valve implantation versus surgical aortic valve replacement for severe aortic stenosis." Annals of cardiothoracic surgery 2.1 (2013): 10-23.
Murashita, Takashi, et al. "Clinical Outcomes After Transapical and Transfemoral Transcatheter Aortic Valve Insertion: An Evolving Experience."The Annals of thoracic surgery 102.1 (2016): 56-61.
Keeble, Thomas R., et al. "Percutaneous balloon aortic valvuloplasty in the era of transcatheter aortic valve implantation: a narrative review." Open Heart3.2 (2016): e000421.
van den Brand, Marcel, et al. "Histological changes in the aortic valve after balloon dilatation: evidence for a delayed healing process." British heart journal 67.6 (1992): 445-449.
Fattouch, Khalil, Sebastiano Castrovinci, and Patrizia Carità. "Aortic valve stenosis: treatments options in elderly high-risk patients." Journal of geriatric cardiology: JGC 13.6 (2016): 473-474.