ESTRO 2024 - Abstract Book

S5294

Radiobiology - Normal tissue radiobiology

ESTRO 2024

Results:

Cardiac irradiation increased diastolic LV wall thickness from 2.1±0.1 mm to 2.8±0.2 mm (p=0.0004), indicating radiation-induced LV remodelling. Cardiac output (figure 1), a measure for LV function, decreased from 100.2±3.2 ml/min to 73.0±7.0 ml/min (p=0.0004) after heart irradiation. Administration of Captopril significantly improved both parameters to 2.0±0.1 mm (p=0.0002) and 91.6±4.5 ml/min (p=0.05), respectively, compared to heart irradiation alone. Combined heart and lung irradiation increased LV posterior wall thickness to 2.7±0.2mm (p=0.04) and decreased cardiac output to 69.7±5.7 ml/min (p<0.0001). Captopril treatment did not improve this. Posterior wall thickness remained increased compared to non-irradiated controls with 2.4±0.2 mm (p<0.0001), while cardiac output stayed reduced at 64.4±6.8 ml/min (p<0.0001). Masson-trichrome staining showed that Captopril reduced collagen deposition in LV tissue. However, after combined heart and lung irradiation, Captopril could not prevent severe collagen deposition (figure 2).

Figure 1: cardiac output 38 weeks after irradiation, with and without captopril treatment.

Figure 2: Masson trichrome staining visualizes collagen deposition in LV tissue 38 weeks after irradiation, with and without captopril treatment.

Conclusion: