Introduction: Use of nitrates is considered contraindicated in severe aortic stenosis (AS) despite lack of scientific evidence to this effect.
Objective: . To evaluate the safety of nitrates in patients presenting with acute pulmonary edema and concomitant moderate or severe AS.
Methhods: A retrospective cohort study was conducted at two Canadian hospitals. Patients admitted with congestive heart failure who received intravenous or sublingual nitroglycerin from 2008 to 2013 were identified. Aortic stenosis presence and severity were defined based on to the American College of Cardiology and American Heart Association guidelines.1 Sixty-five patients with severe AS presenting with pulmonary edema were found to have received nitroglycerin. They were matched to an equal number of patients with moderate AS and patients without AS. Both the group with severe and moderate AS were independently compared to the group without AS. The primary outcome was clinically relevant hypotension, defined as hypotension leading to any of the following predefined events: nitroglycerin discontinuation, intravenous fluid bolus, vasopressor use or cardiac arrest. The main secondary outcome was the occurrence of sustained hypotension, defined as a systolic blood pressure below 90 mmHg lasting 30 minutes or more. Factors predicting clinically relevant hypotension were evaluated.
Results: We included 195 patients equally divided between the three groups. There was no association between AS status and clinically relevant hypotension with an adjusted OR of 0.97 (95% CI 0.40-2.37) and 0.99 (95% CI 0.41-2.41) for moderate and severe AS, respectively. There was a trend towards more sustained hypotension in the group with severe AS with an adjusted OR of 2.34 (95% CI 0.91-6.01). Using multiple logistic regression with model selection, factors more predictive of clinically relevant hypotension were female sex, lower initial systolic blood pressure, higher furosemide dose and use of noninvasive ventilation.
Conclusion: Moderate and severe AS is not associated with more clinically relevant hypotension when using nitroglycerin for acute pulmonary edema. Severe AS may be associated with more sustained hypotension but not requiring increased intervention.
