Ability and efficiency of an automatic analysis software to measure microvascular parameters

Abstract

Analysis of the microcirculation is currently performed offline, is time consuming and operator dependent. The aim of this study was to assess the ability and efficiency of the automatic analysis software CytoCamTools 1.7.12 (CC) to measure microvascular parameters in comparison with Automated Vascular Analysis (AVA) software 3.2. 22 patients admitted to the cardiothoracic intensive care unit following cardiac surgery were prospectively enrolled. Sublingual microcirculatory videos were analysed using AVA and CC software. The total vessel density (TVD) for small vessels, perfused vessel density (PVD) and proportion of perfused vessels (PPV) were calculated. Blood flow was assessed using the microvascular flow index (MFI) for AVA software and the averaged perfused speed indicator (APSI) for the CC software. The duration of the analysis was also recorded. Eighty-four videos from 22 patients were analysed. The bias between TVD-CC and TVD-AVA was 2.20 mm/mm (95 % CI 1.37-3.03) with limits of agreement (LOA) of -4.39 (95 % CI -5.66 to -3.16) and 8.79 (95 % CI 7.50-10.01) mm/mm. The percentage error (PE) for TVD was ±32.2 %. TVD was positively correlated between CC and AVA (r = 0.74, p < 0.001). The bias between PVD-CC and PVD-AVA was 6.54 mm/mm (95 % CI 5.60-7.48) with LOA of -4.25 (95 % CI -8.48 to -0.02) and 17.34 (95 % CI 13.11-21.57) mm/mm. The PE for PVD was ±61.2 %. PVD was positively correlated between CC and AVA (r = 0.66, p < 0.001). The median PPV-AVA was significantly higher than the median PPV-CC [97.39 % (95.25, 100 %) vs. 81.65 % (61.97, 88.99), p < 0.0001]. MFI categories cannot estimate or predict APSI values (p = 0.45). The time required for the analysis was shorter with CC than with AVA system [2'42″ (2'12″, 3'31″) vs. 16'12″ (13'38″, 17'57″), p < 0.001]. TVD is comparable between the two softwares, although faster with CC software. The values for PVD and PPV are not interchangeable given the different approach to assess microcirculatory flow.

A new complimentary web‐based tool for manual analysis of microcirculation videos: Validation of the Capillary Mapper against the current gold standard AVA 3.2

“…Figure presents the respective Bland‐Altman plots for TVD and PVD (n = 50). Percentage error of microcirculatory variables and groups did not exceed the cut‐off of >30% for interchangeability of two methods to determine microcirculatory variables …”

“…In addition, percentage error was calculated (1.96 standard deviation of the mean bias for both software programs divided by the mean of the reference method) . Recently Carsetti et al assumed that new software to determine microcirculatory variables can be considered interchangeable when the percentage error does not exceed >30% . Asymptotic, two‐sided P ‐values smaller than 0.05 were taken as statistically significant.…”

“…However, the analysis of microcirculatory videos is still dependent on the individual investigator, because available programs allow only manual or semi‐manual analyses. This risk of bias would be eliminated with software for automatic analysis, but such programs have so far proven insufficiently accurate on testing . In addition, the few commercially available software packages that have been validated are quite expensive .…”

Journal of Clinical Monitoring and Computing 2017/2018 end of year summary: monitoring—and provocation—of the microcirculation and tissue oxygenation

“…Important advances have been made in recent time in order to bring HVMs to the bedside of critical ill patients, however, issues relating to reliability and feasibility of their clinical application persist as demonstrated by Damiani et al [32] and Carsetti et al [33]. The study by Damiani et al in the October 2017 issue of this journal shows how video quality influences the evaluation of sublingual microcirculation in critically ill patients.…”

“…The work by Carsetti et al [33] in the August 2017 issue of this journal illustrates the second major issue that we are facing: the feasibility as well as the utility of the microcirculatory assessment is diminished by it being time-consuming and operator-dependent and thus, there is an urgent need for a reliable automated analysis software. Carsetti et al compare the automatic analysis software CytoCamTools 1.7.12 (CC) to the most commonly used manual software Automated Vascular Analysis (AVA) 2.2. in terms of TVD of PVD and PPV of small vessels (< 20 µm), as well as a semi-quantitative (AVA) or quantitative (CC) assessment of the type of flow present.…”