Postmortem diagnosis of acute coronary insufficiency and chronic ischemic heart disease by spectrally selective laser autofluorescence polarimetry

Abstract

Background

Myocardial tissue contains a significant number of natural fluorophores. Since each fluorophore has its own characteristic of absorption and emission spectrum, the obtained data carry information about the internal structure of the myocardium.

Myocardial tissue contains a significant number of natural fluorophores. Since each fluorophore has its own characteristic of absorption and emission spectrum, the obtained data carry information about the internal structure of the myocardium.

Methods

In acute coronary insufficiency, as a manifestation of acute hemic hypoxia of cardiomyocytes, there is a reduction of all cytochromes of the respiratory chain with electrons, which can be recorded using the method of laser autofluorescence polarization microscopy. The technique included the following stages:

1. irradiation of a biological tissue sample with a plane-polarized laser beam/

2. measurement of intensity distribution in the plane of an autofluorescence image/

3. statistical analysis of intensity distributions of autofluorescence images.

Comparative analysis of the obtained data showed that the differences between the values of the average statistical moments Mi=1/2/3/4(I) of all orders were statistically significant. At the same time, intergroup overlap is observed for all histograms N(M1).

The most sensitive statistical moments characterizing the N(If ) histograms were identified.

In acute coronary insufficiency, as a manifestation of acute hemic hypoxia of cardiomyocytes, there is a reduction of all cytochromes of the respiratory chain with electrons, which can be recorded using the method of laser autofluorescence polarization microscopy. The technique included the following stages:

1. irradiation of a biological tissue sample with a plane-polarized laser beam/

2. measurement of intensity distribution in the plane of an autofluorescence image/

3. statistical analysis of intensity distributions of autofluorescence images.

Comparative analysis of the obtained data showed that the differences between the values of the average statistical moments Mi=1/2/3/4(I) of all orders were statistically significant. At the same time, intergroup overlap is observed for all histograms N(M1).

The most sensitive statistical moments characterizing the N(If ) histograms were identified.

Results

The obtained data show that samples of both groups demonstrate different intensity distributions of their autofluorescence images.

In the plane of sections of myocardial tissue samples from acute coronary insufficiency and chronic ischemic heart disease, a wide range of protein fiber stacking directions was observed. When studied by this method, the fibrillar network of both types of samples was very similar.

In myocardial tissue affected by acute coronary insufficiency, the porphyrin concentration is higher. Quantitatively, this is manifested in an increase in the half-width of the histogram N(I) and a shift of its extremum towards larger values of І.

The obtained data show that samples of both groups demonstrate different intensity distributions of their autofluorescence images.

In the plane of sections of myocardial tissue samples from acute coronary insufficiency and chronic ischemic heart disease, a wide range of protein fiber stacking directions was observed. When studied by this method, the fibrillar network of both types of samples was very similar.

In myocardial tissue affected by acute coronary insufficiency, the porphyrin concentration is higher. Quantitatively, this is manifested in an increase in the half-width of the histogram N(I) and a shift of its extremum towards larger values of І.

Conclusions

Thus, laser autofluorescence polarization microscopy has significant potential for use as a diagnostic method.

Comparative analysis of the operational characteristics of the polarization-variable autofluorescence method revealed optimal parameters for differentiation of both types of myocardium – statistical moments of the 3rd-4th orders: Se(M3/4) = 86,7% – 93,6%/ Sp(M3/4) = 85,7% – 87,3%/ Ac(M3/4) = 87,3% – 90,4%.

Thus, spectrally selective fluorescence mapping of porphyrins proved effectiveness for the differential diagnosis of postmortem myocardial changes due to acute coronary insufficiency and differentiation with chronic ischemic heart disease. Se(M3/4) ∼90% and Ac(M3/4) ∼ 90% corresponded to the excellent quality of the diagnostic test according to the provisions of evidence-based medicine.

Thus, laser autofluorescence polarization microscopy has significant potential for use as a diagnostic method.

Comparative analysis of the operational characteristics of the polarization-variable autofluorescence method revealed optimal parameters for differentiation of both types of myocardium – statistical moments of the 3rd-4th orders: Se(M3/4) = 86,7% – 93,6%/ Sp(M3/4) = 85,7% – 87,3%/ Ac(M3/4) = 87,3% – 90,4%.

Thus, spectrally selective fluorescence mapping of porphyrins proved effectiveness for the differential diagnosis of postmortem myocardial changes due to acute coronary insufficiency and differentiation with chronic ischemic heart disease. Se(M3/4) ∼90% and Ac(M3/4) ∼ 90% corresponded to the excellent quality of the diagnostic test according to the provisions of evidence-based medicine.