PMC4730648_01
Functional assessment and imaging of chronic thromboembolic material in the pulmonary circulation. a VE/VCO2 ratio during exercise. Lower values indicate better ventilatory efficiency. Compared to a matching athlete (male, 46 y, 177 cm, 70 kg), impaired ventilatory efficiency is visible, reflecting ventilation/perfusion mismatch. b Ventilation-/perfusion (V/Q) scan showing large defects in the right upper lobe and in the left lower lobe. c V/Q scan 12 months after PEA, showing a substantial reduction of previously documented perfusion defects. d Surgical specimen. Successful bilateral pulmonary endarterectomy of wall-adherent thrombotic material with advanced fibrotic remodelling
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Fig1
However, compared to an athlete with a matching exercise capacity, his ventilatory efficiency during exercise was reduced, expressed by an elevated ratio of minute ventilation to CO2 output (VE/VCO2), indicating a ventilation-/perfusion mismatch during exercise (Fig. 1a). A pulmonary ventilation/perfusion scan revealed large bilateral perfusion defects (Fig. 1b), which could be confirmed by CT scan. The patient successfully underwent surgery 3 months after initial presentation (surgical specimen, Fig. 1d). One year after PEA; a follow-up ventilation-/perfusion scan showed minor residual defects (Fig. 1c).
Non-invasive serial measurements in a 43-year old, athletic patient with CTED and normal pulmonary hemodynamics. a CPET results. Constant improvement of ventilatory efficiency after surgery, reflected by decreasing VE/VCO2 ratio and increasing peak PETCO2 values. Delayed improvement of peak VO2. b Results of other non-invasive diagnostic tools established for serial follow-up in PH. Delayed improvement of ventricular function. Constant results of 6-minute walking distance
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Fig2
PEA. Peak oxygen uptake was reduced to 94 % of predicted values, however ventilatory efficiency had improved, reflected by a lower VE/VCO2 ratio (Fig. 2a). Ventilatory efficiency was not normalized but further improved, documented by a lower VE/VCO2 ratio compared to all previous tests (Fig. 2a). In accordance with these findings, CPET showed a sustained improvement of peak oxygen uptake and of ventilatory efficiency, reflected by a decreased VE/VCO2 ratio and substantially higher peak PETCO2 values during exercise (Fig. 2a). TAPSE and NTpro-BNP levels had returned to normal (Fig. 2b).