Correlation Between Myocardial Deformation and Coronary Artery Tortuosity in Patients With Hypertrophic Cardiomyopathy
Condition: Myocardial Deformation; Coronary Artery Anomaly; Hypertrophic Cardiomyopathy; Genetic Mutation; Prognosis
MeSH terms: Cardiomyopathies; Cardiomyopathy, Hypertrophic; Hypertrophy
Study type: Observational

Summary: 
      Correlation between Myocardial Deformation and Coronary Tortuosity and Analysis of Genetic
      Factors Among Hypertrophic Cardiomyopathy Patients
    

Detailed description: 
      Excessive tortuosity of the coronary arteries (TCA) is a somewhat common finding in patients
      referred for coronary angiography, reported in 14-40% of patients referred for angiography.
      The presence of TCA has been associated with chest pain and myocardial perfusion
      abnormalities during stress in the absence of obstructive coronary artery disease. Fluid
      dynamic modeling suggests that stress-induced ischemia may be attributable to a reduction in
      distal coronary artery perfusion pressure from viscous and turbulence energy losses. The
      physiologic reasons for TCA are unclear. The roles of TCA on prognosis of HCM are also needed
      to explore. Pre-clinical studies where elastases and collagenases were used to alter arterial
      morphology together with genetic and pathologic analysis of rare clinical disorders such as
      arterial tortuosity syndrome have indicated that arterial tortuosity arises from
      abnormalities in arterial elastin fibers and extracellular matrix. Apart from inherited
      disorders, some but not all studies have linked TCA with hypertension and female sex, and
      with increased left ventricular (LV) mass from pressure but not volume overload and smaller
      heart size.

      Hypertrophic cardiomyopathy (HCM) is associated with an increased left ventricular (LV) wall
      thickness. HCM is the most common genetic heart disease, characterized by marked clinical and
      morphologic heterogeneity. Diagnosis is usually based on the echocardiographic finding of
      unexplained left ventricular (LV) hypertrophy, defined by increased wall thickness in 1 or
      more LV segments. LV mass is generally assumed to be increased in patients with
      phenotypically expressed HCM, based largely on early pathological studies. TCA among HCM
      patients have not been studied. So, firstly, we choose HCM and non-HCM patients to
      investigate the relationship between TCA and HCM, and further explore the potential roles of
      TCA for prognosis in HCM.

      In HCM patients, disruption of the ordered arrangement of myofibers alters normal cardiac
      mechanical function, resulting in temporal and spatial heterogeneity in regional myocardial
      contractility. Although global LV function is generally unaltered, asynchrony and asynergy in
      regional function lead to delayed diastolic relaxation and impaired diastolic filling. Whilst
      LV ejection fraction is frequently normal in both, LV strain assessment could differentiate,
      compared to normal person. Cardiovascular magnetic resonance (CMR), by virtue of its
      high-resolution volumetric reconstruction of the LV chamber, currently affords a highly
      accurate and reproducible quantitative assessment of mass . So secondly, we sought to
      establish if cardiovascular magnetic resonance myocardial feature tracking (CMR-FT), an
      emerging method allowing accurate assessment of myocardial deformation, differentiates
      between HCM with or without TCA. Additionally, we want to explore the potential genetic
      factor on TCA in HCM.

      This is a single-center, retrospective, case control study that will evaluate the difference
      of TCA between HCM and non-HCM, and explore the prognostic roles of TCA in the first part. In
      the second part, we will use CMR-FT to compare the myocardial strain between HCM with or
      without TCA and analyze the relationship of strain and TCA. In the third part, we choose HCM
      patients and non-HCM to investigate potential genetic factors for TCA in HCM.
    

Intervention name(s): no intervention
Intervention type(s): Other
Intervention description(s): there is no intervention, we just chose patients diagnosed with hypertrophic cardiomyopathy and underwent CAG, and patients without hypertrophic cardiomyopathy as control ,the two groups are matched with age, gender and hypertension.
Observational model: Case-Control
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        Patients with hypertrophic cardiomyopathy and without hypertrophic cardiomyopathy
        undergoing coronary angiography and echocardiography
      
Biospecimen description: 
      blood
    
Keywords: hypertrophic cardiomyopathy; tortuosity of coronary arteries; myocardial strain; prognosis; genetic mutation