Thirsty (for knowledge) Thursday

 

Patient is 72 yo F wtih PMH of HTN, severe aortic stenosis presented to ED with dizziness and shortness of breath, progressively worse over the last 2 weeks, both symptoms worse with exertion. Patient progressively becomes hypotension to 70’s/40’s but still responsive, you strongly suspect this is secondary to the patient’s severe aortic stenosis. What is the pressor of choice in aortic stenosis?

In hypotensive patients with aortic stenosis, Phenylephrine is the vasopressor choice.
Aortic stenosis is the most common cardiac valve lesion in the United States. The underlying cause is progressive calcification and sclerosis of the aortic valve leaflets, due either to a congenital condition (Bicuspid Aortic Valve is found in 1-2% of the population), natural aging calcification, rheumatic valvular disease, or hypercalcemic underlying conditions. The classic triad of symptoms is angina, syncope, and congestive heart failure. Most common EKG findings are evidence of LVH and Left heart strain. [1]

The rationale is 3-fold: (a) if left ventricular afterload is fixed secondary to the stenotic valve, increasing peripheral vascular resistance will not affect the already fixed afterload caused by the lesion; (b) increases in diastolic blood pressure will presumably increase coronary perfusion pressure, and thus myocardial oxygenation; and (c) reflexive bradycardia reduces myocardial stress and oxygen consumption. [2,3]

References

1. O’Gara P, Loscalzo J. Chapter 237. Valvular Heart Disease. In: Longo DL, Fauci AS, Kasper DL, Hauser SL, Jameson J, Loscalzo J. eds. Harrison’s Principles of Internal Medicine, 18e. New York, NY: McGraw-Hill; 2012.

2. Robert H Thiele, Edward C Nemergut, Carl Lynch . The clinical implications of isolated alpha(1) adrenergic stimulation.
Anesth. Analg.: 2011, 113(2);297-304

3. Goertz AW, Lindner KH, Sch├╝tz W, Schirmer U, Beyer M, Georgieff M. Influence of phenylephrine bolus administration on left ventricular filling dynamics in patients with coronary artery disease and patients with valvular aortic stenosis. Anesthesiology. 1994 Jul;81(1):49-58.