Impaired coronary microvascular reactivity in youth with bipolar disorder

Abstract

AbstractBackgroundCardiovascular disease (CVD) is excessively prevalent and premature in bipolar disorder (BD), even after controlling for traditional cardiovascular risk factors. The increased risk of CVD in BD may be subserved by microvascular dysfunction. We examined coronary microvascular function in relation to youth BD.MethodsParticipants were 86 youth, ages 13–20 years (n= 39 BD,n= 47 controls). Coronary microvascular reactivity (CMVR) was assessed using quantitativeT2magnetic resonance imaging during a validated breathing-paradigm. QuantitativeT2maps were acquired at baseline, following 60-s of hyperventilation, and every 10-s thereafter during a 40-s breath-hold. Left ventricular structure and function were evaluated based on 12–15 short- and long-axis cardiac-gated cine images. A linear mixed-effects model that controlled for age, sex, and body mass index assessed for between-group differences in CMVR (time-by-group interaction).ResultsThe breathing-paradigm induced a significant time-related increase inT2relaxation time for all participants (i.e. CMVR;β= 0.36,p< 0.001). CMVR was significantly lower in BDv.controls (β= −0.11,p= 0.002). Post-hoc analyses found lowerT2relaxation time in BD youth after 20-, 30-, and 40 s of breath-holding (d= 0.48,d= 0.72,d= 0.91, respectively; allpFDR< 0.01). Gross left ventricular structure and function (e.g. mass, ejection fraction) were within normal ranges and did not differ between groups.ConclusionYouth with BD showed evidence of subclinically impaired coronary microvascular function, despite normal gross cardiac structure and function. These results converge with prior findings in adults with major depressive disorder and post-traumatic stress disorder. Future studies integrating larger samples, prospective follow-up, and blood-based biomarkers are warranted.