Evaluation of Systemic Microvascular Endothelial Dysfunction in Patients Presenting With Infective Endocarditis
Condition: Infective Endocarditis
MeSH terms: Endocarditis, Bacterial; Endocarditis
Study type: Observational

Summary: 
      Infective endocarditis (IE) is a severe clinical condition with a high in-hospital and 5-year
      mortality. It has a growing incidence, both related to healthcare and possibly to changes in
      prophylaxis recommendations regarding oral procedures. Though not a new disease, several
      aspects in its clinical and laboratory diagnosis remain to be better studied and innovated.
      The evaluation of systemic microvascular disease has proven crucial in the investigation and
      comprehension of pathophysiology of cardiovascular diseases, as well as a tool for early
      diagnosis and prediction of complications. Few studies deal with microcirculation in patients
      with IE, and so far none utilizing speckle contrast imaging and functional capillary density.
      The present study will contribute to the investigation of microcirculatory changes in IE and
      possibly to earlier diagnosis of the condition and/or of its severity and complications. The
      aim of the study is to evaluate the changes in microvascular bed of patients with both acute
      and subacute endocarditis by speckle contrast imaging and skin video-capillaroscopy.
    

Detailed description: 
      This is a cohort study that will include adult patients with active definite infective
      endocarditis by the modified Duke criteria admitted to our center for treatment. A control
      group of healthy volunteers, paired by sex and age, will be included. The microcirculatory
      tests will be performed in an undisturbed quiet room with a defined stable temperature (23 ±
      1 °C) after a 20-minute rest in the supine position. Functional capillary density (FCD)
      defined as the number of spontaneously perfused capillaries per square millimeter of skin
      area will be assessed by video-microscopy system with an epi-illuminated fiber-optic
      microscope containing a 100-W mercury vapor lamp light source and an M200 objective with a
      final magnification of 200×. Images will be acquired and saved for posterior off-line
      analysis using a semi-automatic integrated system (Micro-vision Instruments, Evry, France).
      The mean capillary density for each patient will be calculated as the arithmetic mean of
      visible (i.e., spontaneously perfused) capillaries in three contiguous microscopic fields of
      1mm2 each. Capillary recruitment (capillary reserve) will be evaluated using post-occlusive
      reactive hyperemia (PORH) after arm ischemia for 3 min. Microvascular reactivity will be
      evaluated using an laser speckle contrast imaging (LSCI) system with a laser wavelength of
      785 nm (PeriCam PSI system, Perimed, Sweden) in combination with iontophoresis of
      acetylcholine (ACh), as an endothelium dependent substance, and nitroprusside (endothelium
      independent) for noninvasive and continuous measurement of cutaneous microvascular perfusion
      changes (in arbitrary perfusion units, APU).
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patients with infective endocarditis according to Duke criteria
      
Keywords: infective endocarditis; systemic microcirculation