Surgical pathology of subaortic septal myectomy not associated with hypertrophic cardiomyopathy: a study of 98 cases (1996-2000).
BACKGROUND
No series have described the surgical pathology of subaortic septal myectomy in patients with conditions other than hypertrophic cardiomyopathy (HCM).


METHODS
Medical records and microscopic slides were reviewed from 98 non-HCM patients undergoing septal myectomy at Mayo Clinic Rochester from 1996 to 2000. Concurrently, 204 other patients had myectomy for HCM.


RESULTS
The study group (65 women, 33 men) ranged in age from 1.5 to 92 years (mean, 61). Seventy underwent surgery for aortic stenosis (Group 1), 25 for congenital subaortic stenosis (Group 2) and 3 for other conditions (Group 3). Group 1 patients were older than Group 2 patients (72 vs. 26 years; P<.0001). Microscopic evaluation showed myocyte hypertrophy (97%), vacuolization (35%), left bundle branch tissue (26%) (33% in Group 1 vs. 8% in Group 2; P=.02) and disarray (19%); interstitial fibrosis (92%), inflammation (10%) and amyloidosis (7%, all prealbumin type, all Group 1, >80 years old); arterial thickening (18%) and dysplasia (12%), and dilated venules (6%); and endocardial fibrosis (74%) (64% in Group 1 vs. 100% in Group 2; P=.0001) and chronic inflammation (17%).


CONCLUSIONS
Of 302 patients undergoing subaortic septal myectomy, 32% had conditions other than HCM. Myocyte disarray was present in 19% of patients without HCM (and was absent in 21% of HCM patients in a companion study). Thus, disarray alone cannot be used reliably to include or exclude a diagnosis of HCM in small surgical specimens. Because amyloid was found unexpectedly in seven elderly patients, we recommend routine amyloid staining on surgical myectomy tissue from patients >/=65 years old.
Allen
Rachel D
RD
Mayo Medical School, Mayo Clinic, 200 First Street S.W., Rochester, MN, USA.
Edwards
William D
WD
Tazelaar
Henry D
HD
Danielson
Gordon K
GK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000682:Amyloid / Q000378:metabolism; D001011:Aorta / Q000473:pathology*; D001024:Aortic Valve Stenosis / Q000209:etiology / Q000473:pathology* / Q000601:surgery; D006348:Cardiac Surgical Procedures; D002312:Cardiomyopathy, Hypertrophic / Q000209:etiology / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006346:Heart Septum / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D006352:Heart Ventricles / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000473:pathology; D012189:Retrospective Studies; D014694:Ventricular Outflow Obstruction / Q000150:complications / Q000473:pathology* / Q000601:surgery
D000682:Amyloid