Effect of pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension on stroke volume response to exercise.

In pulmonary hypertension, exercise is limited by an impaired right ventricular (RV) stroke volume response. We hypothesized that improvement in exercise capacity after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) is paralleled by an improved RV stroke volume response. We studied the extent of PEA-induced restoration of RV stroke volume index (SVI) response to exercise using cardiac magnetic resonance imaging (cMRI). Patients with CTEPH (n = 18) and 7 healthy volunteers were included. Cardiopulmonary exercise testing and cMRI were performed before and 1 year after PEA. For cMRI studies, pre- and post-operatively, all patients exercised at 40% of their preoperative cardiopulmonary exercise testing-assessed maximal workload. Post-PEA patients (n = 13) also exercised at 40% of their postoperative maximal workload. Control subjects exercised at 40% of their predicted maximal workload. Preoperatively, SVI (n = 18) decreased during exercise from 35.9 ± 7.4 to 33.0 ± 9.0 ml·m(2) (p = 0.023); in the control subjects, SVI increased (46.6 ± 7.6 vs 57.9 ± 11.8 ml·m(-2), p = 0.001). After PEA, the SVI response (ΔSVI) improved from -2.8 ± 4.6 to 4.0 ± 4.6 ml·m(2) (p <0.001; n = 17). On exercise at 40% of the postoperative maximal workload, SVI did not increase further and was still significantly lower compared with controls. Moreover, 4 patients retained a negative SVI response, despite (near) normalization of their pulmonary hemodynamics. The improvement in SVI response was accompanied by an increased exercise tolerance and restoration of RV remodeling. In conclusion, in CTEPH, exercise is limited by an impaired stroke volume response. PEA induces a restoration of SVI response to exercise that appears, however, incomplete and not evident in all patients.

Surie S ，van der Plas MN ，Marcus JT ，Kind T ，Kloek JJ ，Vonk-Noordegraaf A ，Bresser P ... -  《-》

Pulmonary vascular and right ventricular reserve in patients with normalized resting hemodynamics after pulmonary endarterectomy.

Patients with normalized mean pulmonary artery pressure (mPAP) after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) do not always regain normal exercise capacity. We evaluated right ventricular function, its interaction with both pulsatile and resistive afterload, and the effect of sildenafil during exercise in these patients. Fourteen healthy controls, 15 CTEPH patients, and 7 patients with normalized resting mPAP (≤25 mm Hg) post-PEA underwent cardiopulmonary exercise testing, followed by cardiac magnetic resonance imaging with simultaneous invasive mPAP measurement during incremental supine cycling exercise. Peak oxygen consumption and peak heart rate were significantly reduced in post-PEA and CTEPH patients compared to controls. The mPAP-cardiac output slope was steeper in post-PEA patients than in controls and similar to CTEPH. Relative to controls, resting right ventricular ejection fraction was reduced in CTEPH, but not in post-PEA patients. In contrast, peak exercise right ventricular ejection fraction was reduced both in post-PEA and CTEPH patients. Exercise led to reduction of pulmonary arterial compliance in all groups. Nevertheless, resting pulmonary arterial compliance values in CTEPH and post-PEA patients were even lower than those in controls at peak exercise. In post-PEA patients, sildenafil did not affect resting hemodynamics nor right ventricular function, but decreased the mPAP/cardiac output slope and increased peak exercise right ventricular ejection fraction. Exercise intolerance in post-PEA patients is explained by abnormal pulmonary vascular reserve and chronotropic incompetence. The mPAP/cardiac output slope and pulmonary arterial compliance are sensitive measures demonstrating abnormal resistive and pulsatile pulmonary vascular function in post-PEA patients. These abnormalities are partially attenuated with sildenafil.

Claessen G ，La Gerche A ，Dymarkowski S ，Claus P ，Delcroix M ，Heidbuchel H ... -  《Journal of the American Heart Association》

Right ventricular load at exercise is a cause of persistent exercise limitation in patients with normal resting pulmonary vascular resistance after pulmonary endarterectomy.

Bonderman D ，Martischnig AM ，Vonbank K ，Nikfardjam M ，Meyer B ，Heinz G ，Klepetko W ，Naeije R ，Lang IM ... -  《-》

Evaluation of improvement in exercise capacity after pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension: correlation with echocardiographic parameters.

The study evaluates the alterations in exercise capacity of chronic thromboembolic pulmonary hypertension (CTEPH) patients after pulmonary endarterectomy (PEA) and investigates the echocardiographic parameters associated with the degree of functional recovery. Thirty consecutive patients with the diagnosis of CTEPH (17 males; mean age, 45.9 ± 15.1 years) who had been referred for PEA operation were included in the study. Each patient underwent transthoracic echocardiography and 6-minute walk test (6-MWT) before and 6 months after PEA. After PEA, 6-MWT distances significantly increased (242.8 ± 112.8 m vs. 423.6 ± 89.1 m, p < 0.001), whereas systolic pulmonary artery pressures and right ventricular dimensions significantly decreased (86 ± 25.1 mm Hg vs. 41.9 ± 15.6 mm Hg, p < 0.001 and 42.1 ± 10.1 mm vs. 35.3 ± 5.6 mm, p < 0.001, respectively). Magnitude of change in 6-MWT distance (Δ-6-MWT) was found to be correlated with concomitant change in tricuspid annular plane systolic excursion and left ventricular myocardial performance index (r: 0.518, p: 0.004 and r: -0.385, p: 0.043, respectively). Linear regression analysis revealed preoperative 6-MWT distance as an independent negative predictor of delta-6-MWT (beta: -0.89, t: -3.97, p: 0.001). CTEPH patients with more severely depressed exercise capacity at baseline displayed relatively greater degree of functional recovery after PEA in our study. Improvement in functional capacity was found to be correlated with improvement in parameters reflecting right ventricular functions rather than improvement in pulmonary artery pressure after PEA operation.

Kepez A ，Sunbul M ，Kivrak T ，Eroglu E ，Ozben B ，Yildizeli B ，Mutlu B ... -  《-》

Pulmonary Hemodynamic Response to Exercise in Chronic Thromboembolic Pulmonary Hypertension before and after Pulmonary Endarterectomy.

Richter MJ ，Sommer N ，Gall H ，Voswinckel R ，Seeger W ，Mayer E ，Wiedenroth CB ，Rieth A ，Grimminger F ，Guth S ，Ghofrani HA ... -  《-》