Impact of sex on timing and clinical outcome of septal myectomy for obstructive hypertrophic cardiomyopathy

Background: Sex disparities are common in hypertrophic cardiomyopathy (HCM). Previous research has shown that at time of myectomy, women are older, have greater impairment of diastolic function and more advanced cardiac remodeling. The clinical impact of these differences is unknown. Method: This study included 162 HCM patients (61% men) who underwent septal myectomy. Time to treatment was calculated in relation to symptom onset and diagnosis. Pre- and post-operative echocardiographic data were collected. Sex differences were assessed at baseline and in time-to-event survival analyses for the composite endpoint of all-cause mortality, cardiac transplantation, re-intervention and aborted sudden cardiac death. Results: Women were generally older at time of myectomy (57 vs. 49 years, p < 0.01), with similar time to treatment as measured from symptom onset (2.3 [1.3–6.0] vs. 2.8 [1.1–5.3] years, p > 0.05), but a shorter time since diagnosis compared to men (2.6 [1.2–7.0] vs. 4.3 [2.4–8.3] years, p = 0.02). Mean wall thickness and left atrial diameter were the same for men and women, but were higher in women when correcting for body surface area (absolute: 20 vs. 19 mm, 48 vs 46 mm, p ≥ 0.05; corrected: 9.7 vs. 11.2 mm/m², 23.4 vs. 26.3 mm/m², p < 0.01). After 5.9 [3.0–9.1] years, 15% of men and 8% of women had reached the composite endpoint (p > 0.05). Conclusion: In conclusion, although women present later in life and seem to have more advanced disease on echocardiography, time until myectomy was similar and clinical outcomes after myectomy are favourable for both men and women.