Introduction: Chronic pulmonary embolic disease causes pulmonary hypertension and heart failure. Pulmonary endarterectomy (PEA) is now established as an effective surgical treatment  by removing the obstacle to pulmonary blood flow and hence improving the symptoms of right sided heart failure. While it is understood that load dependent cardiac indices are positively affected, this study aimed at examining load independent indices by evaluating the immediate effect of PEA on right ventricle (RV) and left ventricle (LV) function by pressure volume loops.
Method: We studied RV function in 13 patients (5M:8F) (aged 28-72 years) undergoing elective PEA. Pressure volume loops were generated by a conductance catheter to assess load independent indices of systolic (end systolic pressure volume relationship, ESPVR - mmHg/mL; preload recruitable stroke work, PRSW) and diastolic function (end diastolic pressure volume relationship: EDPVR - mmHg/mL). The end diastolic volume (EDV - mL), dP/dTmax (mmHg/s), time constant of diastolic relaxation (tau - msec), effective arterial elastance (Ea, mmHg/mL), and a measure of ventriculoarterial (V-A) coupling (Ea/Ees), (where Ees is the end systolic elastance) were also measured. In 6 of the patients the same measurements were obtained simultaneously in the LV. All measurements were made with the chest and pericardium open at held end expiration. Data are mean (SD) and statistical analysis was conducted using paired T test.
Results: Immediately after PEA the mean PA pressure was reduced from 50 (16) to 32 (10) mmHg (P < 0.001). Only RV and LV tau were significantly reduced by immediate surgical correction (RV: 48 (13) fell to 38 (10) ms; LV: 65 (47) fell to 38 (4) ms). There was a tendency for RVEDV to fall (149 (80) mL to 103 (62) mL. HR, dP/dTmax, Ea and Ea/Ees, ESPVR, EDPVR and PRSW were not significantly different.
Conclusion: In this study, load independent indices of systolic and diastolic function, as well as V-A coupling indices, were unchanged immediately after PEA. Bi-ventricular diastolic relaxation is however improved, presumably as a result of reduced RV afterload and dilatation.
1 Jamieson SW, Kapelanski DP, Sakakibara N, et al. Pulmonary endarterectomy: experience and lessons learned in 1,500 cases. Ann Thorac Surg