Effect of Diffuse Subendocardial Hypoperfusion on Left Ventricular Cavity Size by 13 N-Ammonia Perfusion PET in Patients With Hypertrophic Cardiomyopathy.

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  • Additional Information
    • Source:
      Publisher: Excerpta Medica Country of Publication: United States NLM ID: 0207277 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-1913 (Electronic) Linking ISSN: 00029149 NLM ISO Abbreviation: Am J Cardiol Subsets: MEDLINE
    • Publication Information:
      Original Publication: New York, NY : Excerpta Medica
    • Subject Terms:
      Coronary Circulation* ; Stroke Volume*; Cardiomyopathy, Hypertrophic/*diagnostic imaging ; Heart Ventricles/*diagnostic imaging ; Myocardial Ischemia/*diagnostic imaging; Adult ; Aged ; Ammonia ; Cardiomyopathy, Hypertrophic/physiopathology ; Female ; Humans ; Male ; Middle Aged ; Myocardial Ischemia/physiopathology ; Myocardial Perfusion Imaging ; Nitrogen Radioisotopes ; Positron-Emission Tomography ; Radiopharmaceuticals
    • Abstract:
      Vasodilator-induced transient left ventricular (LV) cavity dilation by positron emission tomography (PET) is common in patients with hypertrophic cardiomyopathy (HC). Because most patients with PET-LV cavity dilation lack obstructive epicardial coronary artery disease, we hypothesized that vasodilator-induced subendocardial hypoperfusion resulting from microvascular dysfunction underlies this result. To test this hypothesis, we quantified myocardial blood flow (MBF) (subepicardial, subendocardial, and global MBF) and left ventricular ejection fraction (LVEF) in 104 patients with HC without significant coronary artery disease, using 13 NH 3 -PET. Patients with HC were divided into 2 groups, based on the presence/absence of LV cavity dilation (LVvolume stress /LVvolume rest >1.13). Transient PET-LV cavity dilation was evident in 52% of patients with HC. LV mass, stress left ventricular outflow tract gradient, mitral E/E', late gadolinium enhancement, and prevalence of ischemic ST-T changes after vasodilator were significantly higher in patients with HC with LV cavity dilation. Baseline LVEF was similar in the 2 groups, but LV cavity dilation + patients had lower stress-LVEF (43 ± 11 vs 53 ± 10; p <0.001), lower stress-MBF in the subendocardial region (1.6 ± 0.7 vs 2.3 ± 1.0 ml/min/g; p <0.001), and greater regional perfusion abnormalities (summed difference score: 7.0 ± 6.1 vs 3.9 ± 4.3; p = 0.004). The transmural perfusion gradient, an indicator of subendocardial perfusion, was similar at rest in the 2 groups. Notably, LV cavity dilation + patients had lower stress-transmural perfusion gradients (0.85 ± 0.22, LV cavity dilation + vs 1.09 ± 0.39, LV cavity dilation - ; p <0.001), indicating vasodilator-induced subendocardial hypoperfusion. The stress-transmural perfusion gradient, global myocardial flow reserve, and stress-LVEF were associated with LV cavity dilation. In conclusion, diffuse subendocardial hypoperfusion and myocardial ischemia resulting from microvascular dysfunction contribute to development of transient LV cavity dilation in HC.
      (Copyright © 2016 Elsevier Inc. All rights reserved.)
    • Accession Number:
      0 (Nitrogen Radioisotopes)
      0 (Radiopharmaceuticals)
      7664-41-7 (Ammonia)
    • Publication Date:
      Date Created: 20161025 Date Completed: 20170501 Latest Revision: 20170501
    • Publication Date:
      20231215
    • Accession Number:
      10.1016/j.amjcard.2016.08.085
    • Accession Number:
      27771003