Pulmonary Thromboendarterectomy in 106 Patients With Chronic Thromboembolic Pulmonary Hypertension

Pulmonary thromboendarterectomy in chronic thromboembolic pulmonary hypertension: the Spanish experience

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) can be cured by pulmonary endarterectomy (PEA). It is considered the best and only curable treatment option for patients with accessible lesions evaluated as optimal candidates. We describe the experience of the two reference centers in Spain, in order to reinforce the need for referring CTEPH patients to a specialized center to be assessed by a Multidisciplinary Expert Team.

METHODS

We included a population of 338 patients who met the definition for CTEPH and underwent PEA between January 2007 and December 2019. The surgery was indicated in almost 60% of patients assessed. Demographic, anthropometric, hemodynamic and echocardiographic features are listed for PEA patients. Immediate and one-year postoperative outcomes as well as overall mortality were analyzed.

RESULTS

Mean age was 53.5±15.0 years, 53.8% were men; a total of 68.5% were in WHO functional class III-IV; and most of them were in a preoperative hemodynamic condition: mean pulmonary arterial pressure (mPAP) was 46.5±13.1 mmHg and mean pulmonary vascular resistance (PVR) was 764.5±392.8 dyn·s·cm-5. PEA surgery was performed with cardiopulmonary bypass (CBP) and circulatory arrest, with very few complications [including neurological, postoperative reperfusion edema, extracorporeal membrane oxygenation (ECMO) implant and cardiac failure] and optimal postoperative results, where exercise capacity increased and mPAP and PVR values decreased significantly. Presence of persistent pulmonary hypertension (PH) at the six-month right heart catheterization was evaluated. A 3.3% perioperative mortality was achieved. Overall, one-, three- and five-year survival rates were analyzed by Kaplan-Meier's method (94.8%, 93.3% and 90.5% respectively), as well as for residual PH patients. Mortality risk factors were assessed.

CONCLUSIONS

Outstanding PEA results were seen in the immediate, one-year and long-term outcomes. The incidence of complications, including in-hospital mortality and long-term mortality were also below European rates.

A computational model of contributors to pulmonary hypertensive disease: impacts of whole lung and focal disease distributions

Pulmonary hypertension has multiple etiologies and so can be difficult to diagnose, prognose, and treat. Diagnosis is typically made via invasive hemodynamic measurements in the main pulmonary artery and is based on observed elevation of mean pulmonary artery pressure. This static mean pressure enables diagnosis, but does not easily allow assessment of the severity of pulmonary hypertension, nor the etiology of the disease, which may impact treatment. Assessment of the dynamic properties of pressure and flow data obtained from catheterization potentially allows more meaningful assessment of the strain on the right heart and may help to distinguish between disease phenotypes. However, mechanistic understanding of how the distribution of disease in the lung leading to pulmonary hypertension impacts the dynamics of blood flow in the main pulmonary artery and/or the pulmonary capillaries is lacking. We present a computational model of the pulmonary vasculature, parameterized to characteristic features of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension to help understand how the two conditions differ in terms of pulmonary vascular response to disease. Our model incorporates key features known to contribute to pulmonary vascular function in health and disease, including anatomical structure and multiple contributions from gravity. The model suggests that dynamic measurements obtained from catheterization potentially distinguish between distal and proximal vasculopathy typical of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension. However, the model suggests a non-linear relationship between these data and vascular structural changes typical of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension which may impede analysis of these metrics to distinguish between cohorts.

Time trends of pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is considered as a rare but severe complication after acute pulmonary embolism and is potentially curable by pulmonary endarterectomy. We aimed to evaluate, over an 11-year period, time trends of in-hospital outcomes of pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension patients and to investigate predictors of the in-hospital course. We analyzed data on the characteristics, comorbidities, treatments, and in-hospital outcomes for all chronic thromboembolic pulmonary hypertension patients treated with pulmonary endarterectomy in the German nationwide inpatient sample between 2006 and 2016. Overall, 1398 inpatients were included. Annual number of pulmonary endarterectomy increased from 67 in 2006 to 194 in 2016 (P < 0.001), in parallel with a significant decrease of in-hospital mortality (10.9% in 2008 to 1.5% in 2016; P < 0.001). Patients' characteristics shifted slightly toward older age and higher prevalence of chronic renal insufficiency and obesity over time, whereas duration of hospital stay decreased over time. Independent predictors of in-hospital mortality were age (OR 1.03 (95%CI: 1.01-1.05); P = 0.001), right heart failure (2.55 (1.37-4.76); P = 0.003), in-hospital complications such as ischemic stroke (6.87 (1.06-44.70); P = 0.044) and bleeding events like hemopneumothorax (24.93 (6.18-100.57); P < 0.001). Annual pulmonary endarterectomy volumes per center below 10 annual procedures were associated with higher rates of adverse in-hospital outcomes. Annual numbers of chronic thromboembolic pulmonary hypertension patients treated with pulmonary endarterectomy increased markedly in Germany between 2006 and 2016, in parallel with a decrease of in-hospital mortality. Our findings suggest that perioperative management of pulmonary endarterectomy, institutional experience, and patient selection is crucial and has improved over time.

Do Right Heart Hemodynamic Improvements Persist After Pulmonary Thromboendarterectomy?

The survival benefits of pulmonary thromboendarterectomy (PTE) for the treatment of chronic thromboembolic pulmonary hypertension have been well described. However, the significance of right heart hemodynamic changes and their impact on survival remains poorly understood. We sought to characterize the effects of these changes. We conducted a single center, retrospective review of 159 patients who underwent PTE between 1993 and 2015. Echocardiographic and right heart catheterization data were compared longitudinally before and after PTE in order to establish the extent of hemodynamic response to surgery. Kaplan Meier estimates were used to characterize patient survival over time. Univariable and multivariable Cox proportional hazards regression models were used to assess factors associated with long-term mortality. Among the 159 patients studied, 74 (46.5%) were male with a median age of 55 (IQR: 42-66). One-, 5-, 10-, and 15-year survival was 91.0% (95% CI: 86.6-95.6), 79.6% (73.5-86.3), 66.5% (59.2-74.7), and 56.2% (48.1-65.8). Of the 9 candidate risk factors that were evaluated, only advanced age and increased cardiopulmonary bypass time were found to be significantly associated with increased risk of mortality. Pre- and postsurgical echocardiographic imaging data, when available, revealed a median reduction in right ventricular systolic pressure of 29.0 mm Hg (P < 0.0001) and improvement of tricuspid regurgitation (P < 0.0001), both of which appeared to be sustained across long-term follow-up. Improvements in right heart hemodynamics and tricuspid valvular regurgitation persist on long term surveillance following PTE. While patient selection is often driven by the distribution of disease, close postoperative follow up may improve outcomes.

Guidelines on the Diagnosis and Treatment of Pulmonary Hypertension: Summary of Recommendations

Pulmonary hypertension is a hemodynamic disorder defined by abnormally high pulmonary artery pressure that can occur in numerous diseases and clinical situations. The causes of pulmonary hypertension are classified into 5 major groups: arterial, due to left heart disease, due to lung disease and/or hypoxemia, chronic thromboembolic, with unclear and/or multifactorial mechanisms. This is a brief summary of the Guidelines on the Diagnostic and Treatment of Pulmonary Hypertension of the Spanish Society of Pulmonology and Thoracic Surgery. These guidelines describe the current recommendations for the diagnosis and treatment of the different pulmonary hypertension groups.