PMC8018559_01
Pulmonary angiography. (A) Before BPA, (B) during balloon dilatation, (C) after BPA. Organized thrombi in the segmental and subsegmental pulmonary arteries (arrow).
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Pulmonary angiography showed organized thrombi in the segmental or subsegmental pulmonary arteries (Figure 1A).
Lung perfusion scintigraphy before treatment (A) and after treatment (B).
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A transthoracic echocardiogram (TTE) showed severe PH, and lung perfusion scintigraphy showed multiple segmental perfusion defects, which are consistent with CTEPH (Figure 2A). Lung perfusion defects detected by scintigraphy had improved markedly (Figure 2B). Enlargement of the RV and TAPSE were improved after treatment, and GLS-LV remained within the normal range (Figure 4G-I and Table 2).
Clinical course of the patient and changes in various circulation parameters and CAVI.
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The mean pulmonary artery pressure (mPAP) was 51 mmHg, and pulmonary vascular resistance (PVR) was 13.6 wood units (Figure 3). Although his BP was in the normal range, systemic vascular resistance (SVR) was enhanced (Figure 3). Subsequently, symptoms improved from the World Health Organization functional class (WHO-FC) III to II, and brain natriuretic peptide (BNP) level was normalized (Figure 3). After riociguat administration, mPAP and PVR decreased, and CO increased (mPAP 51 mmHg to 41 mmHg, PVR 13.6 wood units to 5.5 wood units, CO 3.3 L/min to 4.8 L/min, Figure 3). The CAVI also improved from 10.0 to 9.1 after riociguat administration, along with the reduction of SVR (26.2 wood units to 18.2 wood units), but BP did not decrease (Figure 3). Six months after the final BPA, mPAP was 19 mmHg, which was within the normal range (Figure 3). Moreover, CAVI decreased to 5.8, which was extremely low for his age (Figure 3).
Changes in echocardiographic findings during treatment. Apical 4-chamber view, short axis view and bull's-eye showing segments of the left ventricle to determine GLS are shown in order. Before riociguat administration (A-C), after riociguat administration (D-F) and after BPA (G-I).
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Moreover, the enlarged RV compressed the interventricular septum, which was shifted leftward (Figure 4A and B). GLS-LV at diagnosis of CTEPH was 10.3%, indicating that LV dysfunction and the impairment of longitudinal strain (LS) was observed in both septal and non-septal LV segments (Figure 4C).  TTE also indicated that GLS-LV improved to 17.2%, and the compression of the LV was released, but PH and RV enlargement still existed (Figure 4D-F). Enlargement of the RV and TAPSE were improved after treatment, and GLS-LV remained within the normal range (Figure 4G-I and Table 2).