Obstructive hypertrophic cardiomyopathy was associated with higher ejection fraction (69% vs 67%, P<0.001) and worse long-term survival over a median 87-month follow-up (131 all-cause deaths).
Cohort (n=1,533)
Yes
Does obstructive hypertrophic cardiomyopathy (HOCM) compared to non-obstructive HCM affect long-term survival and echocardiographic features?
HOCM and a hypercontractile phenotype are associated with worse long-term survival and distinct echocardiographic features, including higher resting coronary flow and left atrial volume, compared to non-obstructive HCM.
Abstract Background The presence of the significant left ventricular outflow tract gradient (LVOTG) changes clinical symptoms, prognosis and treatment in hypertrophic cardiomyopathy enabling the classification into its obstructive (HOCM) and non-obstructive form (non-HOCM). However, the more detailed functional characteristics and comparison of these forms remains poorly known. Purpose To compare the demographic, clinical and echocardiographic features between non-HOCM (defined as LVOTG 30 mmHg) and HOCM patients enrolled into multi-centred study in years 1996-2024 as well as to analyse their long –term prognosis in relation to registered LVOTG. Methods We enrolled 1533 HCM patients (age 51 ± 15 years, 965 males, 63%) with ejection fraction (EF) ≥50%, referred for rest transthoracic echocardiography (TTE) in 27 centers, nevertheless quantitative assessment of LVOTG was available in 1252 patients. Survival analysis was performed in a subset of 1200 patients with follow-up information. Beyond standard TTE, the number of B-lines, the maximal diastolic velocity of coronary flow in left anterior descending artery (LAD) as well as left ventricular force defined as the ratio of systolic blood pressure plus LVOTG divided by left ventricular end-systolic volume was assessed with specification of hypercontractile phenotype (HP) as the highest force quartile. Additionally age and sex matched control group was included. Results Compared to non-HOCM patients, HOCM showed a bit higher body mass index (27 ± 4 vs 26 ± 4 kg/m2, p = 0.001), were often burdened with diabetes and hypertension, presented more advanced NYHA class and higher risk of SCD, see Table. In the echocardiographic assessment HOCM presented lower end-systolic left ventricular volume (LV ESV: 27 ± 14 vs 29 ± 13 ml, p = 0.014) although maintained equal stroke volume and even higher ejection fraction (EF: 69 ± 8% vs 67 ± 7%, p 0.001), cardiac output (CO: 4.3 ± 1.7 vs 4.0 ± 1.4 l/min, p 0.001) and force in comparison to counterparts without LVOTG. This high-contractility performance was however sustained at the cost of larger left atrium volume index (LAVI: 49 ± 19 vs 40 ± 15 ml/m2, p 0.001), higher coronary flow velocity (43 ± 12 vs 27 ± 13 cm/s, p 0.001) as well as more frequent B-lines in the lung assessment. During a median follow-up of 87 months (interquartile range 45 – 143 months), 131 all-cause deaths occurred and not only patients with HOCM but also those with HP showed the worse long-term survival, see Figure. Conclusion HOCM remains the form of HCM burdened with more overt clinical symptoms, signs and prognosis. On the other hand LVOTG seems to be important but not always necessary element of this presentation, which seems to be related even more tightly to general hypercontractility phenotype reflected by higher force and resting coronary flow.Table.Non-HOCM vs HOCM comparison Figure.Force and LVOTG prognostic value
Wierzbowska-Drabik et al. (Thu,) conducted a cohort in Hypertrophic cardiomyopathy (n=1,533). Obstructive hypertrophic cardiomyopathy (HOCM) vs. Non-obstructive hypertrophic cardiomyopathy (non-HOCM) was evaluated on All-cause death. Obstructive hypertrophic cardiomyopathy was associated with higher ejection fraction (69% vs 67%, P<0.001) and worse long-term survival over a median 87-month follow-up (131 all-cause deaths).