Data set characterizing the systemic alterations of microvascular reactivity and capillary density, in patients presenting with infective endocarditis

This article represents data associated with a prior publication from our research group, under the title: Evaluation of microvascular endothelial function and capillary density in patients with infective endocarditis using laser speckle contrast imaging and video-capillaroscopy [1]. Patients with definite infective endocarditis, under stable clinical conditions, were prospectively included. The clinical and laboratory features are presented for each of them in raw form. Microvascular reactivity was evaluated using a laser speckle contrast imaging (LSCI) system with a laser wavelength of 785 nm. LSCI was used in combination with the iontophoresis of acetylcholine (ACh) or sodium nitroprusside (SNP) for the noninvasive, continuous measurement of cutaneous microvascular perfusion changes in arbitrary perfusion units (APU). The images were analyzed using the manufacturer's software. One skin site on the ventral surface of the forearm was chosen for the experiment. Microvascular reactivity was also evaluated using post-occlusive reactive hyperemia, whereby arterial occlusion was achieved with supra-systolic pressure (50 mmHg above the systolic arterial pressure) using a sphygmomanometer for three minutes. Following the release of pressure, maximum flux was measured. Data on cutaneous microvascular density were obtained using intravital video-capillaroscopy. The data obtained may be helpful by showing the usefulness of laser-based noninvasive techniques in systemic infectious diseases other than sepsis, in different clinical settings and countries.

Systemic microvascular reactivity was evaluated using a laser speckle contrast imaging system with (PeriCam PSI system, Perimed, Järfälla, Sweden); Cutaneous capillary density was assessed by high-resolution intra-vital color microscopy (Moritex, Cambridge, UK). Data on patients' clinical and laboratory features were obtained prospectively from their electronic and written notes Data format Raw data on patients' clinical and laboratory features, analyzed data on microvascular parameters obtained Experimental factors The results were presented as the mean 7SD. For values that did not follow a Gaussian distribution, the medians (25th -75th percentiles) were presented (Shapiro-Wilk normality test). The results were analyzed using either twotailed unpaired Student's t-tests or repeated measures ANOVAs when appropriate Experimental features Microvascular reactivity was evaluated using a laser speckle contrast imaging (LSCI) system with a laser wavelength of 785 nm (PeriCam PSI system, Perimed, Järfälla, Sweden). LSCI was used in combination with the iontophoresis of acetylcholine (ACh) or sodium nitroprusside (SNP) for the noninvasive, continuous measurement of cutaneous microvascular perfusion changes in arbitrary perfusion units (APU). The images were analyzed using the manufacturer's software (PIMSoft, Perimed, Järfälla, Sweden). One skin site on the ventral surface of the forearm was chosen for the experiment Data source location National Institute of Cardiology, Ministry of Health, Rio de Janeiro, Brazil Data accessibility All data are presented in the present article

Value of the data
These data may be valuable to show the usefulness of laser-based noninvasive techniques in systemic infectious diseases in different clinical settings and in various countries.
These data describe important systemic microvascular features of patients with definite infective endocarditis (IE) and may serve as a benchmark for the detection of microvascular alterations useful in the diagnosis and management of patients with IE.
These data may be useful for future studies comparing different methodological approaches in the field of study of the microcirculation in infectious diseases.

Data
These data describe the main features of the systemic microvascular alterations detected in patients presenting with definite infective endocarditis, according to the modified Duke criteria. Both endothelium-dependent and -independent microvascular reactivity were evaluated, using cutaneous micro-iontophoresis of acetylcholine or sodium nitroprusside in the forearm, respectively, associated with laser-based technology. Endothelium-dependent microvascular reactivity was also evaluated using post-occlusive reactive hyperemia in the forearm. The data concerning cutaneous microvascular density were obtained using intravital video-capillaroscopy.

Study design and place
This is a comparative study that included patients with a confirmed diagnosis of infective endocarditis who were admitted to the National Institute of Cardiology (NIC) at the Ministry of Health in Rio de Janeiro, Brazil. The NIC is a national reference center for the treatment and research of cardiovascular diseases. Its staff is composed of cardiologists, cardiothoracic surgeons, infectious diseases' specialists, specialized nursing staff, physiotherapists and pharmacists as well as technical staff. The investigative resources include echocardiography, computed tomography, magnetic resonance imaging and scintigraphy. The NIC has outpatient units, four intensive care units and operating theatres where approximately 1300 cardiac surgeries are performed yearly.

Study participants and recruitment
The present study was conducted in accordance with the Declaration of Helsinki 1975, which was revised in 2000, and was approved by the Institutional Review Board (IRB) of the National Institute of Cardiology in Rio de Janeiro, Brazil under protocol # CAAE 52871216.0.0000 and registered at Clin-icalTrials.gov (NCT02940340). Study participants were informed on the nature of the protocol and gave written consent.   The eligibility criteria were as follows: i) confirmed IE according to the modified Duke criteria [2]; ii) inpatient treatment at the NIC; iii) clinical stability at the time of the intervention as evaluated by the investigator; iv) age Z 18 years and v) cardiac surgery performed more than 15 days prior to the protocol date [3,4]. The exclusion criterion was a confirmed previous diagnosis of diabetes mellitus.

Study variables
The variables included were as follows (Table 1): demographic data (sex and age), medical conditions prior to the diagnosis of IE (systemic arterial hypertension, renal failure on conservative or dialytic treatment, smoking, chronic valvular disease, cardiac surgery or percutaneous procedures), predisposing conditions to IE (previous episode of IE, rheumatic valve disease, congenital heart disease, intravenous drug use, valve prosthesis and intracardiac devices), medications in use (angiotensin-converting enzyme inhibitors (ACEi), angiotensin receptor blockers (ARB), statins, betablockers, diuretics), data referring to the episode of IE, such as timing of presentation (acute IE was defined as the presentation of signs and symptoms within one month of diagnosis, and subacute IE as that presenting for more than one month at the time of diagnosis), mode of acquisition (communityacquired and health care-related; the second defined as IE occurring more than 72 hours following hospital admission or acquired within two months of an invasive procedure), etiologic agents. These latter were divided into four groups for analysis: i) viridans group streptococci, including those with blood culture negative, since we have previously shown by PCR of excised valves that viridians streps are the most frequent agents in our scenario IE [5]; ii) aggressive staphylococci (including Staphylococcus aureus both methicillin susceptible and resistant and S. lugdunensis; iii) coagulase negative staphylococci and iv) enterococci. We also evaluated affected structures and left ventricular function, evaluated as normal or moderately to severely compromised at the time of diagnosis of IE; left ventricular ejection fraction was not used as a parameter for heart dysfunction as it is often overestimated in moderate to severe valvular regurgitation, the predominant lesion in IE. Other variables studied were pulmonary artery systolic pressure (PASP), as an indirect measure of myocardial dysfunction, embolic and non-embolic complications (paravalvular abscess, prosthetic dehiscence, atrioventricular block, new cardiac failure, new renal failure); antibiotic and surgical treatment and laboratory data (C-reactive protein levels, CRP, hemoglobin, hematocrit, leukocyte count, and serum creatinine levels).

Intervention
The evaluation of microvascular endothelial function in patients with infective endocarditis was performed using laser speckle contrast imaging. These results were compared to those previously obtained from age and sex-matched healthy volunteers [6]. The systemic microvascular data obtained from this group of healthy volunteers were used as reference microcirculatory values of individuals free of systemic diseases. The healthy volunteers did not present with arterial hypertension, diabetes, dyslipidemia or any other systemic pathology.

Evaluation of microcirculatory reactivity
The microcirculatory tests were performed in the morning between 8 A.M. and 12 P.M. in an undisturbed, quiet room with a defined stable temperature (23 7 1°C), following a 20-min rest period in the supine position. The room temperature was monitored and adjusted if necessary using air conditioning. The acclimatization period lasted until the patient's skin temperature stabilized [7]. We have previously demonstrated that following 15-20 min of acclimatization, the skin temperature stabilizes at approximately 29°C [8]. Table 4 Values of systemic microvascular flow expressed as cutaneous microvascular conductance (CVC), calculated as arbitrary perfusion units (APU) divided by mean arterial pressure, in mmHg, obtained after post-occlusive reactive hyperemia in patients presenting with infective endocarditis (n ¼ 10) or age-and sex-matched healthy individuals (n ¼ 25).

Evaluation of skin microvascular flow and reactivity
Microvascular reactivity was evaluated using a laser speckle contrast imaging (LSCI) system with a laser wavelength of 785 nm (PeriCam PSI system, Perimed, Järfälla, Sweden), as previously described [9] (Fig. 1). LSCI was used in combination with the iontophoresis of acetylcholine (ACh) or sodium nitroprusside (SNP) for the noninvasive, continuous measurement of cutaneous microvascular perfusion changes in arbitrary perfusion units (APU) (Tables 2-4). The images were analyzed using the manufacturer's software (PIMSoft, Perimed, Järfälla, Sweden). One skin site on the ventral surface of the forearm was randomly chosen for the recordings. Hair, broken skin, areas of skin pigmentation and visible veins were avoided, and a single drug-delivery electrode was installed using adhesive discs (LI 611, Perimed, Järfälla, Sweden). A vacuum cushion (AB Germa, Kristianstad, Sweden) was used to reduce the recording artifacts generated by arm movements. The iontophoresis of ACh 2% w/v or SNP 2% w/v (Sigma Chemical CO, USA) was performed using a micropharmacology system (PF 751 PeriIont USB Power Supply, Perimed, Sweden) with increasing anodal currents of 30, 60, 90, 120, 150 and 180 μA for 10-second intervals that are spaced 1 min apart, and the total charges were 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 mC. The dispersive electrode was attached approximately 15 cm away from the iontophoresis chamber. The results of the pharmacological tests were expressed both as peak values (representing the maximal vasodilation observed following the highest dose of ACh or SNP) and as the area under the curve of vasodilation. The measurements of skin blood flow were divided by mean arterial pressure values to provide the cutaneous vascular conductance (CVC) in APUs/mmHg.  Table 5 Values of skin capillary density, obtained using high-resolution intra-vital color video-microscopy, in patients presenting with infective endocarditis (n ¼ 9) or age-and sex-matched healthy individuals (n ¼ 30). Microvascular reactivity was also evaluated using a physiological test known as post-occlusive reactive hyperemia (PORH). During the PORH test, arterial occlusion was achieved with supra-systolic pressure (50 mmHg above the systolic arterial pressure) using a sphygmomanometer for three minutes. Following the release of pressure, maximum flux was measured. PORH was not performed in four patients due to technical reasons.

Capillaroscopy by intravital video-microscopy
The dorsum of the non-dominant middle phalanx was used for image acquisition, while keeping the patient sitting comfortably. The arm was positioned at the level of the heart and immobilized using a vacuum cushion (a specially constructed pillow filled with polyurethane foam that can be molded to any desired shape by creating a vacuum, from AB Germa, Kristianstad, Sweden). Capillary density, i.e., the number of spontaneously perfused capillary loops per square millimeter of skin area, was assessed by high-resolution intra-vital color microscopy (Moritex, Cambridge, UK), as previously described and validated [8,10,11]. We used a 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 were acquired and saved for posterior off-line analysis using a semi-automatic integrated system (Saisam, Microvision Instruments, Evry, France). The mean capillary density for each patient was calculated as the arithmetic mean of visible (i.e., spontaneously perfused) capillaries in three contiguous microscopic fields of 1 mm 2 each ( Fig. 2 and Table 5). The mean number of skin spontaneously perfused capillaries at rest is considered to represent the functional capillary density, as previously described [12]. The features of the study subjects were not available to the investigator during capillary counting. Reproducibility was assessed by examining an identical area of skin. Intra-observer repeatability of data analysis was assessed by reading the same images blindly on two separate occasions (n ¼ 15, coefficient of variability 4.3%).

Statistical analysis
The results were presented as the mean 7SD. For values that did not follow a Gaussian distribution, the medians (25th-75th percentiles) were presented (Shapiro-Wilk normality test). The results were analyzed using either two-tailed unpaired Student's t-tests or repeated measures ANOVAs when appropriate. The independent (unpaired) t-test was used because we compared two unrelated groups, in which the participants (healthy individuals or patients with IE) in each group are different. P values o 0.05 were considered statistically significant. Clinical and laboratory data were shown descriptively. The correlations between the intervention study results (microvascular reactivity) and features of the disease, such as the number of days of presentation, presence of embolic complications and etiological agent, were determined using Pearson's test if the data are found to be of normal distribution (parametric). If the distribution was not normal (non-parametric), Spearman's test was used for the analysis. The identification of potential outliers was performed using the ROUT method (robust regression and outlier removal), which is based on the False Discovery Rate (FDR), with a specified value of Q ¼ 1%.The statistical package used for the statistical analyses was Prism version 6.0 (GraphPad Software Inc. La Jolla, CA, USA) and the R version 3.1.0.