Demographic-based LVH thresholds improves HCM diagnosis

An individual’s age, sex, and body size can affect the normal heart maximum wall thickness (MWT), and using a fixed left ventricular hypertrophy (LVH) threshold of ≥15 mm tends to skew the diagnosis of LVH in patients with hypertrophic cardiomyopathy (HCM) and people with comorbidities, reveals a study.

Researchers measured left ventricular MWT in a reference cohort of healthy adults (n=5,067, no comorbidities), a population cohort (n=43,239, with comorbidities), and an HCM cohort from six international centres (n=2,424). They used cardiovascular magnetic resonance (CMR) and a validated artificial intelligence algorithm for the measurements.

The reference cohort was used to set demographically adjusted LVH thresholds and invidualized z-scores based on age, sex, and body surface area (BSA), which were utilized in assessing other cohorts.

Using the traditional ≥15-mm threshold identified 1,854 participants (4.3 percent) in the population cohort as hypertrophic, with a significant skew by sex (89 percent male). On the other hand, demographic-adjusted LVH thresholds, ranging from 10 to 17 mm, lowered the confirmation to 945 individuals (2.2 percent) and reduced the sex skew (56 percent male).

Similar decreases in bias with age, weight, and height also occurred. In the HCM cohort, the male-to-female ratio was 2:1.

Several patients were diagnosed with HCM despite having MWT below the traditional LVH threshold (<15 mm): 18 percent of male participants and 27 percent of female participants. The use of demographic-adjusted LVH thresholds reduced these figures to 15 percent of male patients and 7 percent of female patients (p<0.0001).

In addition, female patients showed a lower absolute MWT (18 vs 19 mm; p<0.001) but higher MWT z-scores (5.1 vs 4.5; p=0.05).

“A demographic-adjusted approach for LVH improves ascertainment and diagnostic accuracy,” the researchers said.