Determinants of microvascular dysfunction in normotensive offsprings of hypertensive parents

Objective: Microvascular dysfunction usually precedes the onset of hypertension. We hypothesized that offspring of offsprings of hypertensive parents (OHP) would have coronary microvascular dysfunction. Yet, the determinants of microvascular dysfunction in OHP are not fully determined. We, therefore, studied coronary flow reserve (CFR) in OHP in relation to ambulatory blood pressure and lipid profiles. Subjects and Methods: One hundred and twenty-five healthy normotensive offsprings with family history of hypertension and 40 age- and sex-matched healthy normotensive offsprings without family history of hypertension (ONP) were enrolled for the study. All participates underwent transthoracic color Doppler echocardiography at rest and during adenosine (0.14 mg/kg) infusion. CFR was calculated as the ratio between hyperemic diastolic coronary flow to the resting diastolic coronary flow. All participates had ambulatory blood pressure monitoring. In addition, lipid profile was obtained, and triglycerides (TGs)/high-density lipoprotein cholesterol (HDL-C) was calculated. Results: CFR was significantly reduced among OHP compared with ONP (P < 0.001). Moreover, 61 of the OHP (49%) had CFR <2.0. OHP had an exaggerated morning blood pressure surge (MBPS) compared with ONP (P < 0.001). TG/HDL-C was significantly higher in OHP with reduced CFR compared with both OHP without reduced CFR and ONP (P < 0.001). TG/HDL-C was negatively correlated with CFR (P < 0.001). Furthermore, TG/HDL-C ratio was positively correlated with MBPS (P < 0.001). Multivariate analysis showed that BPMS and TG/HDL-C were independent predictors for reduced CFR in OHP (P < 0.001). Receiver-operating characteristic analysis showed that TG/HDL-c ratio ≥3.8 and MBPS ≥49 mmHg were the optimal cutoff values to predict reduced CFR among OHP, with (area under the curve = 0.91 and 0.92, respectively; P < 0.001). Conclusion: Our study suggests that microvascular function is significantly impaired in OHP. TG/HDL-C ratio and MBPS are independently associated with reduced CFR. These relationships could potentially reflect a subclinical precursor of cardiovascular risks and future hypertension, a premise that warrants close follow-up.