Management of the Crashing Aortic Stenosis Patient

Author: David Lebowitz, MD (@DrDaveLebo, EM Attending Physician, Assistant Professor of Emergency Medicine at University of Central Florida College of Medicine) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Brit Long, MD (@long_brit, EM Chief Resident at SAUSHEC, USAF)

Case 1: On your next shift, a 68 year-old female presents with shortness of breath that started last night. Her Temperature is 98.5 Fahrenheit, Heart Rate 97, Respiratory Rate 26, Oxygen saturation 88% on room air, and Blood Pressure 210/115. Based on your exam you suspect a CHF exacerbation; however, you auscultated a systolic murmur. Upon review of her medical record, you find that she was diagnosed with severe aortic stenosis based on her last echocardiogram.

Case 2: At the end of your shift, a 75 year-old male with a history of aortic stenosis presents with decreased responsiveness. His Temperature is 99.1 Fahrenheit, Heart Rate 92, Respiratory Rate 24, Oxygen Saturation 93% on room air, and Blood Pressure 70/34.

The most common valvular heart abnormality is Aortic Stenosis. Congenital bicuspid aortic valves can frequently lead to stenosis due to calcifications. Calcification of the normal aortic valve as well as rheumatic heart disease can advance to aortic stenosis.^[i] Once symptomatic with aortic stenosis, the mortality rate is around 25% per year.^[ii]

Diagnosis of new onset aortic stenosis in the Emergency Department can be difficult. Patients may present with syncope, angina, and/or dyspnea, but this depends on the severity of disease. On exam, a murmur may be auscultated that is classically a crescendo-decrescendo systolic ejection murmur that radiates to the carotids. ECG commonly shows signs of left-ventricular hypertrophy and nonspecific ST-wave and T-wave abnormalities. Chest radiography may depict a boot shaped heart. Echocardiogram is the diagnostic test of choice.^[iii]

Stable patients with new onset symptomatic aortic stenosis should be evaluated for valve replacement.^[iv] Patients with severe congestive heart failure and pulmonary edema present us with a treatment dilemma. Antihypertensive medications have been associated with a sudden decline in cardiac output which can cause severe hypotension. According to the 2014 AHA/ACC Valvular Heart Disease Guidelines, vasodilator therapy may lower the afterload which can improve cardiac output. Vasodilators, such as nitroprusside can be used in patients with severe aortic stenosis and NYHA class IV heart failure, but they should be under invasive hemodynamic monitoring.^{[v] [vi]} One trial showed that nitroprusside leads to improved cardiac output in a subset of patients in the intensive care setting.^[vii] Since this was studied in patients under hemodynamic monitoring in the intensive care setting, one must use caution in applying this in the Emergency Department. However, a recent retrospective chart review studied patients with moderate and severe aortic stenosis and pulmonary edema who were given nitroglycerin in the Emergency Department. They did not find a significant difference in the rates of clinically relevant hypotension between patients with moderate aortic stenosis, severe aortic stenosis, and patients without aortic stenosis.^[viii] It is unclear though if vasodilators actually improve outcomes in this subset of patients in the Emergency Department.

Aortic Stenosis patients who present with cardiogenic shock can be resuscitated with intravenous fluids, as they are preload dependent. Inotropic medications such as dopamine and dobutamine can also be used in patients in shock, but definitively, these patients will need aortic valve replacement.^[ix] Severe aortic stenosis patients who are unstable in cardiogenic shock or acute pulmonary edema should be considered for percutaneous aortic balloon dilatation for stabilization, acting as a bridge to valve replacement.^[x]

Summary: The management of the critically ill aortic stenosis patient can be very challenging. These patients need a valve replacement, so consulting cardiothoracic surgery as soon as possible is prudent. The crashing aortic stenosis patient in cardiogenic shock should be resuscitated with fluids and inotropic medications such as dopamine and dobutamine. The hypertensive aortic stenosis patient with acute pulmonary edema, should be management cautiously. Nitroprusside can be considered, but it has only been studied in patients undergoing invasive hemodynamic monitoring in the ICU setting. Based on recent data, nitroglycerin may be safe in the ED setting, but this should be used with caution, and it is unknown if this even improves outcomes.

References / Further Reading

^[i] Chen RS, Bivens MJ, & Grossman SA. Diagnosis and Management of Valvular Heart Disease in Emergency Medicine. Emerg Med Clin N Am 2011;29:801-810

^[ii] Carabello BA, Paulus WJ. Aortic Stenosis. The Lancet 2009;373:956-966

^[iii] Carabello BA, Paulus WJ. Aortic Stenosis. The Lancet 2009;373:956-966

^[iv] Carabello BA, Paulus WJ. Aortic Stenosis. The Lancet 2009;373:956-966

^[v] Nishimura, RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC Valvular Heart Disease Guideline for the Management of Patients with Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;63(22):e57-e185.

^[vi] Khot UN, Novaro GM, Popovic ZB, et al. Nitroprusside in Critically Ill Patients with Left Ventricular Dysfunction and Aortic Stenosis. N Eng J Med. 2003;348:1756-63

^[vii] Khot UN, Novaro GM, Popovic ZB, et al. Nitroprusside in Critically Ill Patients with Left Ventricular Dysfunction and Aortic Stenosis. N Eng J Med. 2003;348:1756-63

^[viii] Claveau D, Piha-Gossack A, Friedland SN, et al. Complications Associated with Nitrate Use in Patients Presenting with Acute Pulmonary Edema and Concomitant Moderate or Severe Aortic Stenosis. Ann Emerg Med 2015;66(4):355-362

^[ix] Chen RS, Bivens MJ, & Grossman SA. Diagnosis and Management of Valvular Heart Disease in Emergency Medicine. Emerg Med Clin N Am 2011;29:801-810

^[x] Nishimura, RA, Otto CM, Bonow RO, et al. 2014 AHA/ACC Valvular Heart Disease Guideline for the Management of Patients with Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;63(22):e57-e185.