Distensibility Index: Results are shown in Figure 5 and Table 2. DI of the AAO and MPA was not significantly different either in or between volunteers and patients and there was also no significant difference in the DI of RPA and LPA in volunteers. Compared with patients, DI of the RPA in the control group was significantly higher than DI of LTX and native lung arteries (p<0.05), whereas DI of the LPA was not significantly different from the DI of the patient’s pulmonary vessels; however, overall DI showed higher values in the control group. Changes in vessel area of RPA and LPA as well as LTX and native pulmonary artery over the cardiac cycle in one volunteer and one patient are demonstrated in Figure 6.
Discussion
Since the transplantation of an isolated lung has become an important surgical option in the treatment of end-stage lung disease, there is much interest in the postoperative behavior of the right side of the heart and the pulmonary circulation. Canadian health mall read more Early reports of SLTX for pulmonary fibrosis described a significant decrease in PVR and pulmonary artery pressure following successful transplantation. These promising hemodynamic changes after SLTX lead to a further extension of SLTX indications to other groups of patients with pulmonary vascular diseases associated with pulmonary hypertension as an alternative to combined heart-lung transplantation.
Responses of right heart function to LTX are well described. They consist primarily of an increase in right ventricular ejection fraction and stroke volume accompanied by a decrease in end-systolic and diastolic right ventricular volumes. In addition, the posttransplant normalization of PVR is reflected by a decrease in preejection periods and an increase in acceleration times as assessed by duplex-Doppler echocardiography of the pulmonary valve.
However, the assessment of pulmonary hemodynamics and especially the determination of differential lung perfusion requires invasive techniques, such as cardiac cathetherization or the application of radioactive isotopes. Since cardiac cathetherization is prone to several complications, its application is restricted and it is not an ideal follow-up technique.

Table 2—DI Calculated in AAO, MPA, RPA, and LPA and in LTX and Native Pulmonary Artery, Both in SLTX Patients and Normal Subjects

Mean SD
Normal subjects
AAO 0.2 0.13
MPA 0.2.3 0.12
RPA 0.38 0.11
LPA 0.3 0.08
Patients
AAO 0.14 0.07
MPA 0.23 0.15
LTX 0.24 0.1
Native 0.21 0.06

Figure 5. DI, calculated in AAO, MPA, RPA, and LPA of normal subjects and in AAO, MPA, native, and transplanted pulmonary artery of SLTX patients.Figure 5. DI, calculated in AAO, MPA, RPA, and LPA of normal subjects and in AAO, MPA, native, and transplanted pulmonary artery of SLTX patients.

Figure 6. Profiles of vessel area over cardiac cycle. Top: RPA and LPA of a normal volunteer; bottom: native and transplanted pulmonary artery of a SLTX patient.Figure 6. Profiles of vessel area over cardiac cycle. Top: RPA and LPA of a normal volunteer; bottom: native and transplanted pulmonary artery of a SLTX patient.