Systolic blood pressure ≤110 mm Hg is associated with severe coronary microvascular ischemia and higher risk for ventricular arrhythmias in hypertrophic cardiomyopathy

Abstract

Background: Coronary microvascular dysfunction (CMD) and hypertension (HTN) occur frequently in hypertrophic cardiomyopathy (HCM), but whether blood pressure (BP) influences CMD and outcomes is unknown.

Objective: The purpose of this study was to test the hypothesis that HTN is associated with worse CMD and outcomes.

Methods: This retrospective study included 690 HCM patients. All patients underwent cardiac magnetic resonance imaging, echocardiography, and rhythm monitoring; 127 patients also underwent rest/vasodilator stress ¹³NH₃ positron emission tomography myocardial perfusion imaging. Patients were divided into 3 groups based on their rest systolic blood pressure (SBP) (group 1 ≤110 mm Hg; group 2 111-140; group 3 >140 mm Hg) and were followed for development of ventricular tachycardia (VT)/ventricular fibrillation (VF), heart failure (HF), death, and composite outcome.

Results: Group 1 patients had the lowest age and left ventricular (LV) mass but the highest prevalence of nonobstructive hemodynamics and restrictive diastolic filling. LV scar was similar in the 3 groups. Group 1 had the lowest rest and stress myocardial blood flow (MBF) and highest SDS (summed difference score). Rest SBP was positively correlated with stress MBF and negatively correlated with SDS. Group 1 had the highest incidence of VT/VF, whereas the incidences of HF, death, and composite outcome were similar among the 3 groups. In multivariate analysis, rest SBP ≤110 mm Hg was independently associated with VT/VF (hazard ratio 2.6; 95% confidence interval 1.0-6.7; P = .04).

Conclusion: SBP ≤110 mm Hg is associated with greater severity of CMD and coronary microvascular ischemia and higher incidence of ventricular arrhythmias in HCM.

Keywords: Hypertrophic cardiomyopathy; Myocardial blood flow; Rest systolic blood pressure; Summed difference score; Ventricular fibrillation; Ventricular tachycardia.

Graphical abstract

Figure 1

Flowchart illustrating hypertrophic cardiomyopathy (HCM) patient selection. BP = blood pressure; PET = positron emission tomography.

Figure 2

Distribution of rest systolic blood pressure (SBP) and rest diastolic blood pressure (DBP) in hypertrophic cardiomyopathy patients. Group 1: Rest SBP ≤110 mm Hg; group 2: rest SBP 111–140 mm Hg; group 3: rest SBP >140 mm Hg.

Figure 3

Scatter plots of stress myocardial blood flow (MBF) and left ventricular mass index (LVMI) (A), rest systolic blood pressure (SBP) (B), rest mean arterial blood pressure (MAP) (C), and rest pulse pressure (PP) (D). In hypertrophic cardiomyopathy, left ventricular mass is negatively correlated with hyperemic (stress) MBF, whereas rest (prevasodilator) SBP, MAP, and PP are positively correlated with hyperemic MBF.

Figure 4

Kaplan Meier curves of ventricular tachycardia (VT/ventricular fibrillation (VF) (A), heart failure (HF) (B), all-cause death (C), and composite outcome (D) in hypertrophic cardiomyopathy patients. Group 1: Rest SBP ≤110 mm Hg; group 2: rest SBP 111–140 mm Hg; group 3: rest SBP >140 mm Hg. Group 1 patients had the highest incidence of VT/VF; however, HF, all-cause death, and the composite outcome were similar across the 3 groups.

Supplemental Figure 1