Prognostic value of exercise tolerance test for predicting cardiovascular disease in asymptomatic individuals with heterozygous familiar hypercholesterolemia

Myocardial strain impairment, heterozygous familial hypercholesterolemia and systemic arterial hypertension: Is there a link?

Dyslipidemia is known as a strong risk factor for premature atherosclerotic cardiovascular disease and increased morbidity and mortality and can have an adverse effect on left ventricular function due to direct or indirect macrovascular and/or microvascular damage. Speckle-tracking echocardiography allows the assessment of subclinical cardiac dysfunction in different diseases on the basis of myocardial deformation indices, and decrease in longitudinal and circumferential strain was shown in patients with heterozygous familial hypercholesterolemia (heFH) without comorbidities. In this issue of the journal a new study presents the results in a well-defined population which included asymptomatic treatment-naive heFH individuals without known coronary/peripheral arterial disease, with normal left ventricular ejection fraction and no other risk factors as formal arterial hypertension or diabetes mellitus. A slight impairment of global longitudinal strain was present, despite normal standard echocardiographic parameters. Also, the higher rise in systolic and diastolic blood pressure of heHF patients during exercise treadmill test might reflect early preclinical hypertension. High cholesterol level may have produced endothelial dysfunction, which has been shown to be related to the extent of atherosclerotic process and cardiovascular damage. Relevant findings are reported on left ventricular strain reduction and increase in systolic/diastolic blood pressure in asymptomatic heFH males. The relationship between myocardial strain impairment and developing systemic arterial hypertension in hypercholesterolemic patients could be the subject of further subsequent investigation.

Reduced global longitudinal strain at rest and inadequate blood pressure response during exercise treadmill testing in male heterozygous familial hypercholesterolemia patients

Background

Heterozygous familial hypercholesterolemia (heFH) is a genetic disorder leading to premature coronary artery disease (CAD). We hypothesized that the subclinical pathophysiologic consequences of hypercholesterolemia may be detected before the occurrence of clinically overt CAD by stress testing and myocardial strain imaging.

Patients-methods

We evaluated the treadmill tests (ETTs) of 46 heFH men without known arterial hypertension/diabetes mellitus/vasculopathy like CAD and of 39 healthy men matched for age, baseline systolic/diastolic blood pressure (BP) and heart rate (HR), using Bruce protocol. Global longitudinal strain (GLS) of the left ventricle (LV) additionally to ejection fraction was obtained.

Results

heFH men reached a significantly higher peak systolic and diastolic BP compared to controls (p = 0.002 and p < 0.001, respectively). Mean rate pressure product was significantly higher in heFH patients (p = 0.038). Both duration of the ETT and workload in metabolic equivalents was lower in the heFH group (p < 0.001 and p < 0.001, respectively). Baseline to peak rise of systolic and diastolic BP in heFH men was higher (p = 0.008 and p < 0.001 for systolic and diastolic BP, respectively). Furthermore, heFH men had higher rise of HR from baseline to peak, compared to controls; (p = 0.047). GLS in heHF men was slightly decreased (p = 0.014), although the ejection fraction was similar in both groups.

Conclusion

heFH men have a higher rise in systolic/diastolic BP during ETT, which may reflect early, preclinical hypertension. Furthermore, slight impairment of LV GLS is present, despite the absence of apparent myocardial dysfunction in conventional 2D echocardiography.