Pulmonary thromboendarterectomy-the Royal Papworth experience

Can my echo work as a crystal ball? - Echocardiographic parameters predicting residual pulmonary hypertension after pulmonary endarterectomy

INTRODUCTION AND OBJECTIVES

Pulmonary endarterectomy should be considered in all patients with chronic thromboembolic pulmonary hypertension. Twenty five percent of patients maintain pulmonary hypertension after pulmonary endarterectomy, with therapeutic and prognostic implications. We aimed to evaluate echocardiographic parameters at diagnosis as predictors for development of residual pulmonary hypertension.

METHODS

Retrospective, observational, unicentric study of patients with confirmed chronic thromboembolic pulmonary hypertension who underwent pulmonary endarterectomy between January 2010 and October 2024. All patients underwent transthoracic echocardiogram at diagnosis. After pulmonary endarterectomy, patients had a right heart catheterization to exclude residual pulmonary hypertension (mean pulmonary artery pressure ≥30 mmHg). Right heart echocardiographic parameters were assessed and compared.

RESULTS

Thirty-nine patients had chronic thromboembolic pulmonary hypertension and underwent pulmonary endarterectomy during the follow-up period. Mean age at diagnosis was 57.3 years-old. Eighteen patients had documented residual pulmonary hypertension. Tricuspid annular plane systolic excursion (p=0.010), end-diastolic right ventricular area (p<0.001), end-systolic right ventricular area (p<0.001), fractional area change (p=0.006), tricuspid annular plane systolic excursion/pulmonary artery systolic pressure ratio (p=0.002), diastolic (p=0.002) and systolic eccentric ratio (p=0.036) were significantly different between the two groups. End-systolic right ventricular area and end-diastolic right ventricular area were independently associated with residual pulmonary hypertension (p=0.023 and p=0.013), and those with end-diastolic right ventricular area above 27.13 cm2 (area under the curve [AUC] 0.88, sensitivity 89%, specificity 85%, odds ratio 44) and end-systolic right ventricular area >19.54 cm2 (AUC 0.875, sensitivity 88%, specificity 85%, odds ratio 38.5) had higher probability of developing residual pulmonary hypertension after pulmonary endarterectomy.

CONCLUSION

This study shows that certain echocardiographic parameters could be predictors of development of residual pulmonary hypertension after pulmonary endarterectomy; however, validation in larger cohorts is mandatory.

Pulmonary Thromboendarterectomy: The Potentially Curative Treatment of Choice for Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a consequence of unresolved organized thromboembolic obstruction of the pulmonary arteries, which can cause pulmonary hypertension and right ventricular failure. Owing to its subtle signs, determining its exact incidence and prevalence is challenging. Furthermore, CTEPH may also present without any prior venous thromboembolic history, contributing to underdiagnosis and undertreatment. Diagnosis requires a high degree of suspicion and is ruled out by a normal ventilation/perfusion ratio scintigraphy. Additional imaging by computed tomography and/or conventional angiography, as well as right heart catheterization, are required to confirm CTEPH and formulate treatment plans. Pulmonary thromboendarterectomy is the treatment of choice for eligible patients and can be potentially curative. Pulmonary thromboendarterectomy has a low mortality rate of 1% to 2% at expert centers and offers excellent long-term survival. Furthermore, recent advances in the techniques allow distal endarterectomy with comparable outcomes. Alternative treatment options are available for those who may not be operable or have prohibitive risks, providing some benefit. However, CTEPH is a progressive disease with low long-term survival rates if left untreated. Given excellent short- and long-term outcomes of surgery, as well as the benefits seen with other treatment modalities in noncandidate patients, it is crucial that precapillary pulmonary hypertension and CTEPH are ruled out in any patient with dyspnea of unexplained etiology. These patients should be referred to expert centers where accurate operability assessment and appropriate treatment strategies can be offered by a multidisciplinary team.

Outcomes of Multidisciplinary Care at a Chronic Thromboembolic Pulmonary Hypertension Center

Recent international guidelines recommend a multidisciplinary evaluation and care model for patients with chronic thromboembolic pulmonary hypertension (CTEPH), but there is a paucity of supporting data. The aim of this study was to describe the outcomes of a multidisciplinary team approach to the comprehensive care of CTEPH patients. This single-center cohort study enrolled 166 consecutive adult patients undergoing CTEPH treatment evaluation from 2016 to 2022 at a tertiary care, academic regional referral and comprehensive CTEPH center with pulmonary thromboendarterectomy (PTE) and balloon pulmonary angioplasty (BPA) capabilities. Patients underwent PTE, BPA, or medical management after consensus evaluation by a multidisciplinary team including pulmonary hypertension physicians, surgeons, interventional cardiologists, and radiologists. 86% (142/166) of patients underwent interventional therapies; 100 (60%) underwent PTE and 42 (25%) BPA. Of the 24 (14%) medically treated patients, 13 patients were offered but deferred intervention; 11 patients had non-intervenable disease. 30-day mortality in both PTE and BPA was 0%. 1- and 3-year survival was 99% and 96% for PTE, 100% and 93% for BPA, 79% and 79% for medical management. Patients who underwent PTE had the best hemodynamic response (∆PVR: PTE -278.8 ± 366.9 dyne/sec/cm5; BPA -15.9 ± 171.8 dyne/sec/cm5; medical -60.2 ± 233.1 dyne/sec/cm5; p = 0.001), largest improvement in Borg Dyspnea Scale; [PTE -1.0 (-2.8 to 0.0), BPA + 0.5 (-0.8 to 5.0), medical +1.0 (0.75 to 3.0), p = 0.01], and most improvement in NYHA functional class [% improving at least 1 functional class: PTE 64% (47/73), BPA 18% (5/28), medical 21% (4/19), p = 0.0004].

Impact of the establishment of a multidisciplinary national chronic thromboembolic pulmonary hypertension board on a monocentric surgical endarterectomy program

OBJECTIVES

Chronic thromboembolic pulmonary hypertension is a rare disease, characterized by delays in diagnosis and curative surgical treatment. After establishing a surgical pulmonary endarterectomy centre in Switzerland and due to a historically low resection rate of 14%, a national multidisciplinary evaluation board was established in January 2018. Herein, we summarize the impact of the board on our programme.

METHODS

Patients discussed in the national chronic thromboembolic pulmonary hypertension board from January 2018 to December 2023 were included. Clinical characteristics, treatment allocation and survival were compared between patients undergoing surgery, patients refusing surgery and non-operable patients. Fisher's exact test or three-way ANOVA and Kaplan-Meier analyses were used.

RESULTS

188 patients were discussed at our national chronic thromboembolic pulmonary hypertension board; 131 (70%) presented with operable disease, 77 (41%) were referred for pulmonary endarterectomy and 34 (18%) of operable patients declined surgery. There is a significant difference in survival between these groups (P = 0.048). One- and 2-year survival in the subgroup undergoing pulmonary endarterectomy was 97% and 79%, respectively, while 1- and 2-year survival in the subgroup refusing pulmonary endarterectomy was 91% and 76%, respectively. The pulmonary endarterectomy rate has increased from a historical low of 14-41% since establishing the board.

CONCLUSIONS

Establishing an interdisciplinary board is essential to address diagnostic and management challenges in chronic thromboembolic pulmonary hypertension patients. The Swiss national chronic thromboembolic pulmonary hypertension board played an important role in substantially increasing the rate of curative surgery.

The volume-outcome relationship for pulmonary endarterectomy in chronic thromboembolic pulmonary hypertension

BACKGROUND

We conducted a volume-outcome meta-analysis of pulmonary endarterectomy procedures for chronic thromboembolic pulmonary hypertension to objectively determine the minimum required annual case load that can define a high-volume centre.

METHODS

Three electronic databases were systematically queried up to 1 May 2024. Centres were divided in volume tertiles. The primary outcomes were early mortality and long-term survival. Restricted cubic splines were used to demonstrate the volume-outcome relationship and the elbow-method was applied to define high-volume centres. Long-term survival was assessed using Cox frailty models.

RESULTS

We included 51 centres (52 consecutive cohorts) and divided them into tertiles (T1: <6 cases per year; T2: 6-15 cases per year, T3: >15 cases per year), comprising a total 11 345 patients (mean age 52.3 years). Overall early mortality was 6.0% (T1: 11.6%; T2: 7.2%; T3: 5.2%; p<0.001), for which a significant nonlinear volume-outcome relationship was observed (p=0.0437) with a statistically determined minimal required volume of 33 cases per year (95% CI 29-35 cases), and a modelled volume of 40 cases per year corresponding to a 5.0% mortality rate. Nevertheless, early mortality still progressively declined in higher volume centres (from 6.7% to 5.4% to 2.9% in centres performing 16-50, 51-100 and >100 procedures annually). In addition, a significant volume effect was observed for long-term survival (adjusted hazard ratio per tertile 0.75, 95% CI 0.63-0.89; p=0.001).

CONCLUSION

There is a significant association between procedural volume and early mortality in pulmonary endarterectomy. An annual procedural volume of >33-40 cases per year may be used to define a high‑volume centre, although higher volumes still lead to progressively lower mortality rates.

Chronic thromboembolic pulmonary hypertension: A comprehensive review of pathogenesis, diagnosis, and treatment strategies

Chronic thromboembolic pulmonary hypertension (CTEPH) is part of group 4 of the pulmonary hypertension (PH) classification and generally affects more than a third of patients referred to PH centers. It is a three-compartment disease involving proximal (lobar-to-segmental) and distal (subsegmental) pulmonary arteries that are obstructed by persistent fibrothrombotic material, and precapillary pulmonary arteries that can be affected as in pulmonary arterial hypertension. It is a rare complication of pulmonary embolism (PE), with an incidence of around 3% in PE survivors. The observed incidence of CTEPH in the general population is around six cases per million but could be three times higher than this, as estimated from PE incidence. However, a previous venous thromboembolic episode is not always documented. With advances in multimodality imaging and therapeutic management, survival for CTEPH has improved for both operable and inoperable patients. Advanced imaging with pulmonary angiography helps distinguish proximal from distal obstructive disease. However, right heart catheterization is of utmost importance to establish the diagnosis and hemodynamic severity of PH. The therapeutic strategy relies on a stepwise approach, starting with an operability assessment. Pulmonary endarterectomy (PEA), also known as pulmonary thromboendarterectomy, is the first-line treatment for operable patients. Growing experience and advances in surgical technique have enabled expansion of the distal limits of PEA and significant improvements in perioperative and mid- to long-term mortality. In patients who are inoperable or who have persistent/recurrent PH after PEA, medical therapy and/or balloon pulmonary angioplasty (BPA) are effective treatment options with favorable outcomes that are increasingly used. All treatment decisions should be made with a multidisciplinary team that includes a PEA surgeon, a BPA expert, and a chest radiologist.

Not Just CTEPH: A Narrative Review on the Spectrum Approach to Postpulmonary Embolism Conditions

Three mutually exclusive entities can underlie a postpulmonary embolism syndrome (PPES): not obstructed postpulmonary embolism syndrome (post-PE dyspnea), chronic thromboembolic pulmonary disease (CTEPD), and chronic thromboembolic pulmonary hypertension (CTEPH). Cardiorespiratory impairment in CTEPH and CTEPD underlies respiratory and hemodynamic mechanisms, either at rest or at exercise. Gas exchange is affected by the space effect, the increased blood velocity, and, possibly, intracardiac right to left shunts. As for hemodynamic effects, after a period of compensation, the right ventricle dilates and fails, which results in retrograde and anterograde right heart failure. Little is known on the pathophysiology of post-PE dyspnea, which has been reported in highly comorbid with lung and heart diseases, so that a "two-hit" hypothesis can be put forward: it might be caused by the acute myocardial damage caused by pulmonary embolism in the context of preexisting cardiac and/or respiratory diseases. More than one-third of PE survivors develops PPES, with only a small fraction (3-4%) represented by CTEPH. A value of ≈3% is a plausible estimate for the incidence of CTEPD. Growing evidence supports the role of CTEPD as a hemodynamic phenotype intermediate between post-PE dyspnea and CTEPH, but it still remains to be ascertained whether it constantly underlies exercise-induced pulmonary hypertension and if it is a precursor of CTEPH. Further research is needed to improve the understanding and the management of CTEPD and post-PE dyspnea.

Balloon pulmonary angioplasty for proximal chronic thromboembolic pulmonary hypertension in patients ineligible for pulmonary endarterectomy

Balloon pulmonary angioplasty (BPA) to treat chronic thromboembolic pulmonary hypertension (CTEPH) is generally reserved for distal obstruction precluding pulmonary endarterectomy (PEA) but can be used in patients with proximal disease who are at high surgical risk or refuse surgery. This single-center retrospective study compared BPA efficacy in patients with proximal versus distal CTEPH. Of the 478 patients, 36 had proximal disease, follow-up was 11.6 months and mean number of BPA 6. After BPA, PVR, and mean pulmonary artery pressure decreased significantly in the proximal and distal groups (from 6.5 to 4.0 WU and 39 to 31 mmHg and from 7.6 to 3.8 WU and 44 to 31 mmHg, respectively, p < 0.001 for all comparisons). NYHA class also improved significantly in both groups, from 3 to 2, whereas the 6-min walk distance, cardiac output, and serum NT pro-BNP showed significant improvements only in the distal group. Thus, when PEA for CTEPH is technically feasible but not performed due to severe comorbidities or patient refusal, BPA can produce significant hemodynamic improvements, albeit less marked than in patients with distal disease. Better patient selection to BPA might improve outcomes in patients with proximal disease who are ineligible for PEA.

Long-term effects of pulmonary endarterectomy on pulmonary hemodynamics, cardiac function, and exercise capacity in chronic thromboembolic pulmonary hypertension

BACKGROUND

Long-term changes in exercise capacity and cardiopulmonary hemodynamics after pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH) have been poorly described.

METHODS

We analyzed the data from 2 prospective surgical CTEPH cohorts in Hammersmith Hospital, London, and Amsterdam UMC. A structured multimodal follow-up was adopted, consisting of right heart catheterization, cardiac magnetic resonance imaging, and cardiopulmonary exercise testing before and after PEA. Preoperative predictors of residual pulmonary hypertension (PH; mean pulmonary artery pressure >20 mm Hg and pulmonary vascular resistance ≥2 WU) and long-term exercise intolerance (VO2max <80%) at 18 months were analyzed.

RESULTS

A total of 118 patients (61 from London and 57 from Amsterdam) were included in the analysis. Both cohorts displayed a significant improvement of pulmonary hemodynamics, right ventricular (RV) function, and exercise capacity 6 months after PEA. Between 6 and 18 months after PEA, there were no further improvements in hemodynamics and RV function, but the proportion of patients with impaired exercise capacity was high and slightly increased over time (52%-59% from 6 to 18 months). Long-term exercise intolerance was common and associated with preoperative diffusion capacity for carbon monoxide (DLCO), preoperative mixed venous oxygen saturation, and postoperative PH and right ventricular ejection fraction (RVEF). Clinically significant RV deterioration (RVEF decline >3%; 5 [9%] of 57 patients) and recurrent PH (5 [14%] of 36 patients) rarely occurred beyond 6 months after PEA. Age and preoperative DLCO were predictors of residual PH post-PEA.

CONCLUSIONS

Restoration in exercise tolerance, cardiopulmonary hemodynamics, and RV function occurs within 6 months. No substantial changes occurred between 6 and 18 months after PEA in the Amsterdam cohort. Nevertheless, long-term exercise intolerance is common and associated with postoperative RV function.

How Would I Treat My Own Chronic Thromboembolic Pulmonary Hypertension in the Perioperative Period?

Chronic thromboembolic pulmonary hypertension (CTEPH) results from an incomplete resolution of acute pulmonary embolism, leading to occlusive organized thrombi, vascular remodeling, and associated microvasculopathy with pulmonary hypertension (PH). A definitive CTEPH diagnosis requires PH confirmation by right-heart catheterization and evidence of chronic thromboembolic pulmonary disease on imaging studies. Surgical removal of the organized fibrotic material by pulmonary endarterectomy (PEA) under deep hypothermic circulatory arrest represents the treatment of choice. One-third of patients with CTEPH are not deemed suitable for surgical treatment, and medical therapy or interventional balloon pulmonary angioplasty presents alternative treatment options. Pulmonary endarterectomy in patients with technically operable disease significantly improves symptoms, functional capacity, hemodynamics, and quality of life. Perioperative mortality is <2.5% in expert centers where a CTEPH multidisciplinary team optimizes patient selection and ensures the best preoperative optimization according to individualized risk assessment. Despite adequate pulmonary artery clearance, patients might be prone to perioperative complications, such as right ventricular maladaptation, airway bleeding, or pulmonary reperfusion injury. These complications can be treated conventionally, but extracorporeal membrane oxygenation has been included in their management recently. Patients with residual PH post-PEA should be considered for medical or percutaneous interventional therapy.

Systematic pulmonary embolism follow-up increases diagnostic rates of chronic thromboembolic pulmonary hypertension and identifies less severe disease: results from the ASPIRE Registry

BACKGROUND

Diagnostic rates and risk factors for the subsequent development of chronic thromboembolic pulmonary hypertension (CTEPH) following pulmonary embolism (PE) are not well defined.

METHODS

Over a 10-year period (2010-2020), consecutive patients attending a PE follow-up clinic in Sheffield, UK (population 554 600) and all patients diagnosed with CTEPH at a pulmonary hypertension (PH) referral centre in Sheffield (referral population estimated 15-20 million) were included.

RESULTS

Of 1956 patients attending the Sheffield PE clinic 3 months following a diagnosis of acute PE, 41 were diagnosed with CTEPH with a cumulative incidence of 2.10%, with 1.89% diagnosed within 2 years. Of 809 patients presenting with pulmonary hypertension (PH) and diagnosed with CTEPH, 32 were Sheffield residents and 777 were non-Sheffield residents. Patients diagnosed with CTEPH at the PE follow-up clinic had shorter symptom duration (p<0.01), better exercise capacity (p<0.05) and less severe pulmonary haemodynamics (p<0.01) compared with patients referred with suspected PH. Patients with no major transient risk factors present at the time of acute PE had a significantly higher risk of CTEPH compared with patients with major transient risk factors (OR 3.6, 95% CI 1.11-11.91; p=0.03). The presence of three computed tomography (CT) features of PH in combination with two or more out of four features of chronic thromboembolic pulmonary disease at the index PE was found in 19% of patients who developed CTEPH and in 0% of patients who did not. Diagnostic rates and pulmonary endarterectomy (PEA) rates were higher at 13.2 and 3.6 per million per year, respectively, for Sheffield residents compared with 3.9-5.2 and 1.7-2.3 per million per year, respectively, for non-Sheffield residents.

CONCLUSIONS

In the real-world setting a dedicated PE follow-up pathway identifies patients with less severe CTEPH and increases population-based CTEPH diagnostic and PEA rates. At the time of acute PE diagnosis the absence of major transient risk factors, CT features of PH and chronic thromboembolism are risk factors for a subsequent diagnosis of CTEPH.

Evaluation and Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is a treatable form of pulmonary hypertension and right heart failure. CTEPH (group 4 pulmonary hypertension) is caused by persistent organized thromboembolic obstruction of the pulmonary arteries from incompletely resolved acute pulmonary embolism. CTEPH also may present without prior VTE history, which can contribute to its underrecognition. The true incidence of CTEPH is unclear, but is estimated to be approximately 3% after acute pulmonary embolism. V˙/Q˙ scintigraphy is the best screening test for CTEPH, with CT scan imaging and other advanced imaging methods now playing a larger role in disease detection and confirmation. Perfusion defects on V˙/Q˙ scintigraphy in the setting of pulmonary hypertension are suggestive of CTEPH, but pulmonary angiography and right heart catheterization are required for confirmation and treatment planning. CTEPH potentially is curative with pulmonary thromboendarterectomy surgery, with mortality rates of approximately 2% at expert centers. Advances in operative techniques are allowing more distal endarterectomies to be performed successfully with favorable outcomes. However, more than one-third of patients may be considered inoperable. Although these patients previously had minimal therapeutic options, effective treatments now are available with pharmacotherapy and balloon pulmonary angioplasty. Diagnosis of CTEPH should be considered in all patients with suspicion of pulmonary hypertension. Treatments for CTEPH have advanced with improvements in outcomes for both operable and inoperable patients. Therapy should be tailored based on multidisciplinary team evaluation to ensure optimal treatment response.

Can regional cerebral oxygen saturation monitoring during circulatory arrest time predict postoperative neurological dysfunction in patients undergoing surgical pulmonary thromboendarterectomy? Useful index for short- and long-term outcomes

A hypothermic circulatory arrest is usually used to correct thoracic aorta pathologies. The emergency treatment of acute type A aortic dissection and elective repair of aortic arch pathologies are the most common indications for using hypothermic circulatory arrest. A hypothermic circulatory arrest can also be used for surgical pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension. Intervals with total circulatory arrest offer a clear surgical field for thrombus and emboli removal from the pulmonary artery branches. The price to pay for intermittent circulatory arrest during pulmonary thromboendarterectomy is postoperative neurological dysfunction due to brain hypothermia and hypoperfusion. A noninvasive method for cerebral monitoring during cardiac surgery is real-time regional cerebral oxygen saturation (rSO2 ). Liu et al. report that continuous monitoring of rSO2 during surgical pulmonary thromboendarterectomy may reduce the long cerebral hypoperfusion time and prevent postoperative neurological dysfunction.