Preoperative Factors That Predict Recurrence After Repair of Discrete Subaortic Stenosis

Abstract

Background: Several factors predict reintervention for subaortic stenosis (SubAS): age, preoperative left ventricular outflow tract gradient, distance from the obstructive subaortic ridge to the aortic valve, and peeling of membrane from the aortic/mitral valves. We sought to develop a prediction rule to categorize risk of reintervention for recurrent SubAS and guide follow-up in patients with discrete SubAS.

Methods: We retrospectively reviewed patients who underwent SubAS resection between 1984 and 2016. Our primary outcome was reintervention for recurrent SubAS after discharge. Kaplan-Meier estimates were used for time-to-event analysis of any reintervention. Multivariable models were used to create a prediction rule. We excluded patients without 3 years of follow-up.

Results: Of 172 patients, 21 (12.2%) required reintervention. The characteristics predicting reintervention were age younger than 2 years (P < .001), preoperative left ventricular outflow tract gradient of 65 mm Hg or more (P = .011), peeling of membrane from the mitral valve (P < .001), distance from the membrane to the aortic valve of less than 5 mm (P < .001), prior complex operation (P = .035), other left-sided heart lesions (P = .008), and aortic annulus z-score of -2.5 or less (P < .001). Our final prediction rule includes age, membrane to aortic valve distance, and other left-sided heart lesions each scored as 1 point. For patients with a score of 1 or less, 4% required a reintervention compared with 34% with a score of 2 or more.

Conclusions: A prediction rule that incorporates the patient's age at the index operation, membrane to aortic valve distance, and associated left-sided heart lesions can determine the likelihood of reintervention for recurrent SubAS.