Mid term effects of pulmonary thromboendarterectomy on clinical and cardiopulmonary function status

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.

Chronic thromboembolic pulmonary hypertension: realising the potential of multimodal management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare complication of acute pulmonary embolism. Important advances have enabled better understanding, characterisation, and treatment of this condition. Guidelines recommending systematic follow-up after acute pulmonary embolism, and the insight that CTEPH can mimic acute pulmonary embolism on initial presentation, have led to the definition of CTEPH imaging characteristics, the introduction of artificial intelligence diagnosis pathways, and thus the prospect of easier and earlier CTEPH diagnosis. In this Series paper, we show how the understanding of CTEPH as a sequela of inflammatory thrombosis has driven successful multidisciplinary management that integrates surgical, interventional, and medical treatments. We provide imaging examples of classical major vessel targets, describe microvascular targets, define available tools, and depict an algorithm facilitating the initial treatment strategy in people with newly diagnosed CTEPH based on a multidisciplinary team discussion at a CTEPH centre. Further work is needed to optimise the use and combination of multimodal therapeutic options in CTEPH to improve long-term outcomes for patients.

Pulmonary endarterectomy and balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension: Comparison of changes in hemodynamics and functional capacity

The treatment of choice for chronic thromboembolic pulmonary hypertension (CTEPH) is pulmonary endarterectomy (PEA). Balloon pulmonary angioplasty (BPA) is an emerging option for inoperable patients. Comparisons of the hemodynamic and functional outcome between these treatments are scarce. In this single-center observational cohort study, we compared hemodynamics by right heart catheterization and peak oxygen consumption before and 5 months (±14 days) after either PEA or BPA. Comprehensive evaluation and selection for PEA or BPA was performed by an expert CTEPH team. Fourty-two and fourty consecutive patients were treated with PEA or BPA, respectively. Demographics were similar between groups. Both PEA and BPA significantly reduced mean pulmonary artery pressure (from 46 ± 11 mmHg at baseline to 28 ± 13 mmHg at follow-up; p < 0.001 and from 43 ± 12 mmHg to 31 ± 9 mmHg; p < 0.001) and pulmonary vascular resistance (from 686 ± 347 dyn s cm-5 at baseline to 281 ± 197 dyn s cm-5 at follow-up; p < 0.001 and from 544 ± 322 dyn s cm-5 to 338 ± 180 dyn s cm-5; p < 0.001), with significantly lower reductions for both parameters in the former group. However, cardiopulmonary exercise testing revealed no significant between group differences in exercise capacity. Diffusion capacity for carbon monoxide at baseline was the only follow-up predictor for peak VO2. In our study, PEA reduced pulmonary pressures more than BPA did, but similar improvements were observed for exercise capacity. Thus, while long term data after BPA is lacking, BPA treated CTEPH patients can expect physical gains in line with PEA.

Exercise hyperventilation and pulmonary gas exchange in chronic thromboembolic pulmonary hypertension: Effects of balloon pulmonary angioplasty

BACKGROUND

Excessive ventilation (V̇E) and abnormal gas exchange during exercise are features of chronic thromboembolic pulmonary hypertension (CTEPH). In selected CTEPH patients, balloon pulmonary angioplasty (BPA) improves symptoms and exercise capacity. How BPA affects exercise hyperventilation and gas exchange is poorly understood.

METHODS

In this longitudinal observational study, symptom-limited cardiopulmonary exercise tests and carbon monoxide lung diffusion (DLCO) were performed before and after BPA (interval, mean (SD): 3.1 (2.4) months) in 36 CTEPH patients without significant cardiac and/or pulmonary comorbidities.

RESULTS

Peak work rate improved by 20% after BPA whilst V̇E at peak did not change despite improved ventilatory efficiency (lower V̇E with respect to CO₂ output [V̇CO₂]). At the highest identical work rate pre- and post-BPA (75 (30) watts), V̇E and alveolar-arterial oxygen gradient (P(Ai-a)O₂) decreased by 17% and 19% after BPA, respectively. The physiological dead space fraction of tidal volume (VD/VT), calculated from measurements of arterial and mixed expired CO₂, decreased by 20%. In the meantime, DLCO did not change. The best correlates of P(Ai-a)O₂ measured at peak exercise were physiological VD/VT before BPA and DLCO after BPA.

CONCLUSIONS

Ventilatory efficiency, physiological VD/VT, and pulmonary gas exchange improved after BPA. The fact that DLCO did not change suggests that the pulmonary capillary blood volume and probably the true alveolar dead space were unaffected by BPA. The correlation between DLCO measured before BPA and P(Ai-a)O₂ measured after BPA suggests that DLCO may provide an easily accessible marker to predict the response to BPA in terms of pulmonary gas exchange.

Balloon pulmonary angioplasty vs. pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension: a systematic review and meta-analysis

Although balloon pulmonary angioplasty (BPA) and pulmonary endarterectomy (PEA) are effective in chronic thromboembolic pulmonary hypertension (CTEPH), the comparison of their efficacy and safety is still unclear. We identified studies through a systematic review of PubMed, Cochrane Library, and Embase and used a random effects meta-analysis model to synthesize estimates of weighted mean differences or combined effect size. In total, 54 studies were included in this meta-analysis. The survival rates at perioperative/in-hospital period, 2 years, and 3 years were 100%, 99%, and 97%, respectively, in BPA group and 93%, 90%, and 88%, respectively, in PEA group. The variation of 6-min walk distance was 141.80 m in BPA and 100.73 m in PEA when the follow-up was 1-6 months. At < 1-month, 1-6-month, and > 12-month follow-up, the changed results of mean pulmonary arterial pressure were - 18.31, - 17.00, and - 12.97 mmHg in BPA group and - 18.93, - 21.21, and - 21.35 mmHg in PEA group. At < 1-month and 1-6-month follow-up, the changed values of pulmonary vascular resistance were - 542.24 and - 599.77 dyne•s•cm^-5 in PEA group and - 443.49 and - 280.00 dyne•s•cm^-5 in BPA group. In addition, there was more wide variety of complications in PEA group than in BPA group. BPA might have higher survival rate (perioperative/in-hospital period, 2-year and 3-year follow-up) and fewer types of complications compared with PEA. The improvement in exercise capacity (1-6-month follow-up) in the BPA group might be more pronounced than in PEA group. Moreover, PEA might be superior in improvement of hemodynamic parameters (< 1-month, 1-6-month, and > 12-month follow-up).

Factors predicting outcome after pulmonary endarterectomy

Objective

Few studies have reported predictive factors of outcome after pulmonary endarterectomy (PEA) in chronic thromboembolic pulmonary hypertension. The purpose of this study was to determine factors influencing mortality and predictors of hemodynamic improvement after PEA.

Methods

A total of 383 consecutive patients who underwent PEA between January 2005 and December 2009 were retrospectively reviewed. Among them, 150 were fully reevaluated 7.5±1 months after PEA by NYHA class, 6–minute walk distance (6MWD), percentage of predicted carbon monoxide transfer factor (TL_CO) and right heart catheterisation.

Results

Mortality rates at 1 month, 1 year and 3 years were 2.8%, 6.9% and 7.5%, respectively. Preoperative pulmonary vascular resistance (PVR) independently predicted 1-month, 1- and 3-year mortality and age predicted mortality at 1 year and 3 years. Significant improvement in NYHA class and 6MWD were observed and PVR decreased from 773±353 to 307±221 dyn.sec.cm^-5 (p<0.001). In 96 patients (64%), PVR decreased by at least 50% and/or was reduced to lower than 250 dyn.sec.cm^-5. Preoperative cardiac output (CO) and TL_CO predicted hemodynamic improvement.

Conclusion

PEA is associated with an excellent long-term survival and a marked improvement in clinical status and hemodynamics. Some preoperative factors including PVR, CO and TL_CO can predict postoperative outcomes.

Severe Pulmonary Arteriopathy Is Associated with Persistent Hypoxemia after Pulmonary Endarterectomy in Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by occlusion of pulmonary arteries by organized chronic thrombi. Persistent hypoxemia and residual pulmonary hypertension (PH) following successful pulmonary endarterectomy (PEA) are clinically important problems; however, the underlying mechanisms remain unclear. We have previously reported that residual PH is closely related to severe pulmonary vascular remodeling and hypothesize that this arteriopathy might also be involved in impaired gas exchange. The purpose of this study was to evaluate the association between hypoxemia and pulmonary arteriopathy after PEA.

METHODS AND RESULTS

Between December 2011 and November 2014, 23 CTEPH patients underwent PEA and lung biopsy. The extent of pulmonary arteriopathy was quantified pathologically in lung biopsy specimens. We then analyzed the relationship between the severity of pulmonary arteriopathy and gas exchange after PEA. We observed that the severity of pulmonary arteriopathy was negatively correlated with postoperative and follow-up PaO2 (postoperative PaO2: r = -0.73, p = 0.0004; follow-up PaO2: r = -0.66, p = 0.001), but not with preoperative PaO2 (r = -0.373, p = 0.08). Multivariate analysis revealed that the obstruction ratio and patient age were determinants of PaO2 one month after PEA (R2 = 0.651, p = 0.00009). Furthermore, the obstruction ratio and improvement of pulmonary vascular resistance were determinants of PaO2 at follow-up (R2 = 0.545, p = 0.0002). Severe pulmonary arteriopathy might increase the alveolar-arterial oxygen difference and impair diffusion capacity, resulting in hypoxemia following PEA.

CONCLUSION

The severity of pulmonary arteriopathy was closely associated with postoperative and follow-up hypoxemia.

Exercise physiological responses to drug treatments in chronic thromboembolic pulmonary hypertension

We tested the hypothesis that patients with chronic thromboembolic pulmonary hypertension (CTEPH) that was deemed to be inoperable were more likely to respond to drugs for treating pulmonary arterial hypertension (PAH) by using cardiopulmonary exercise (CPX) testing than those with CTEPH that was deemed to be operable. We analyzed CPX testing data of all patients with CTEPH who were treated with PAH drugs and had undergone CPX testing before and after treatment at a single pulmonary hypertension center between February 2009 and March 2013. Suitability for pulmonary endarterectomy (PEA) was decided by experts in PEA who were associated with a treatment center. The group with inoperable CTEPH included 16 patients, the operable group included 26 patients. There were no differences in demographics and baseline hemodynamic data between the groups. Unlike patients in the operable group, after drug treatment patients with inoperable CTEPH had a significantly higher peak V̇o2 (P < 0.001), work load (P = 0.002), and oxygen pulse (P < 0.001). In terms of gas exchange, there was an overall net trend toward improved V̇e/V̇co2 in the group with inoperable CTEPH, with an increased PaCO2 (P = 0.01), suggesting reduced hyperventilation. No changes were observed in patients with operable CTEPH. In conclusion, treatment with PAH drug therapy reveals important pathophysiological differences between inoperable and operable CTEPH, with significant pulmonary vascular and cardiac responses in inoperable disease. Drug effects on exercise function observed in inoperable CTEPH cannot be translated to all forms of CTEPH.

Pulmonary vascular diseases

Diseases of the pulmonary vasculature are a cause of increased pulmonary vascular resistance (PVR) in pulmonary embolism, chronic thromboembolic pulmonary hypertension (CTEPH), and pulmonary arterial hypertension or decreased PVR in pulmonary arteriovenous malformations on hereditary hemorrhagic telangiectasia, portal hypertension, or cavopulmonary anastomosis. All these conditions are associated with a decrease in both arterial PO2 and PCO2. Gas exchange in pulmonary vascular diseases with increased PVR is characterized by a shift of ventilation and perfusion to high ventilation-perfusion ratios, a mild to moderate increase in perfusion to low ventilation-perfusion ratios, and an increased physiologic dead space. Hypoxemia in these patients is essentially explained by altered ventilation-perfusion matching amplified by a decreased mixed venous PO2 caused by a low cardiac output. Hypocapnia is accounted for by hyperventilation, which is essentially related to an increased chemosensitivity. A cardiac shunt on a patent foramen ovale may be a cause of severe hypoxemia in a proportion of patients with pulmonary hypertension and an increase in right atrial pressure. Gas exchange in pulmonary arteriovenous malformations is characterized by variable degree of pulmonary shunting and/or diffusion-perfusion imbalance. Hypocapnia is caused by an increased ventilation in relation to an increased pulmonary blood flow with direct peripheral chemoreceptor stimulation by shunted mixed venous blood flow.

An Australian tertiary referral center experience of the management of chronic thromboembolic pulmonary hypertension

The objective of this study was to report the outcome of pulmonary endarterectomy (PEA) surgery performed for chronic thromboembolic pulmonary hypertension (CTEPH) at a single tertiary center. The prospective study consisted of 35 patients with surgically amenable CTEPH undergoing PEA between September 2004 and September 2010. The main outcome measures were Functional (New York Heart Association [NYHA] class, 6-Minute Walk Distance), hemodynamic (echocardiography, right heart catheterization, and cardiac MRI), and outcome data (morbidity and mortality). Following PEA, there were significant improvements in NYHA class (pre 2.9±0.7 vs. post 1.3±0.5, P < 0.0001), right ventricular systolic pressure (pre 77.4±24.8 mmHg vs. post 45.1±24.9 mmHg, P = 0.0005), 6-Minute Walk Distance (pre 419.6±109.4 m vs. post 521.6±83.5 m, P = 0.0017), mean pulmonary artery pressure (pre 41.8±15.3 mmHg vs. post 24.7±8.8 mmHg, P = 0.0006), and cardiac MRI indices (end diastolic volume pre 213.8±49.2 mL vs. post 148.1±34.5 mL, P < 0.0001; ejection fraction pre 40.7±9.8 mL vs. post 48.1±8.9 mL, P = 0.0069). The mean cardiopulmonary bypass time was 258.77±26.16 min, with a mean circulatory arrest time of 43.83±28.78 min, a mean ventilation time of 4.7±7.93 days (range 0.2-32.7), and a mean intensive care unit stay of 7.22±8.71 days (range 1.1-33.8). Complications included reperfusion lung injury (20%), persistent pulmonary hypertension (17.1%), slow respiratory wean (25.7%), pericardial effusion (11.4%), and cardiac tamponade (5.7%). 1-year mortality post-procedure was 11.4%. Pulmonary endarterectomy can be performed safely with relatively low mortality.

Diagnostic evaluation and management of chronic thromboembolic pulmonary hypertension: a clinical practice guideline

BACKGROUND

Pulmonary embolism is a common condition. Some patients subsequently develop chronic thromboembolic pulmonary hypertension (CTEPH). Many care gaps exist in the diagnosis and management of CTEPH patients including lack of awareness, incomplete diagnostic assessment, and inconsistent use of surgical and medical therapies.

METHODS

A representative interdisciplinary panel of medical experts undertook a formal clinical practice guideline development process. A total of 20 key clinical issues were defined according to the patient population, intervention, comparator, outcome (PICO) approach. The panel performed an evidence-based, systematic, literature review, assessed and graded the relevant evidence, and made 26 recommendations.

RESULTS

Asymptomatic patients postpulmonary embolism should not be screened for CTEPH. In patients with pulmonary hypertension, the possibility of CTEPH should be routinely evaluated with initial ventilation/perfusion lung scanning, not computed tomography angiography. Pulmonary endarterectomy surgery is the treatment of choice in patients with surgically accessible CTEPH, and may also be effective in CTEPH patients with disease in more 'distal' pulmonary arteries. The anatomical extent of CTEPH for surgical pulmonary endarterectomy is best assessed by contrast pulmonary angiography, although positive computed tomography angiography may be acceptable. Novel medications indicated for the treatment of pulmonary hypertension may be effective for selected CTEPH patients.

CONCLUSIONS

The present guideline requires formal dissemination to relevant target user groups, the development of tools for implementation into routine clinical practice and formal evaluation of the impact of the guideline on the quality of care of CTEPH patients. Moreover, the guideline will be updated periodically to reflect new evidence or clinical approaches.

Management of massive and submassive pulmonary embolism, iliofemoral deep vein thrombosis, and chronic thromboembolic pulmonary hypertension: a scientific statement from the American Heart Association

Venous thromboembolism (VTE) is responsible for the hospitalization of >250 000 Americans annually and represents a significant risk for morbidity and mortality. Despite the publication of evidence-based clinical practice guidelines to aid in the management of VTE in its acute and chronic forms, the clinician is frequently confronted with manifestations of VTE for which data are sparse and optimal management is unclear. In particular, the optimal use of advanced therapies for acute VTE, including thrombolysis and catheter-based therapies, remains uncertain. This report addresses the management of massive and submassive pulmonary embolism (PE), iliofemoral deep vein thrombosis (IFDVT),and chronic thromboembolic pulmonary hypertension (CTEPH). The goal is to provide practical advice to enable the busy clinician to optimize the management of patients with these severe manifestations of VTE. Although this document makes recommendations for management, optimal medical decisions must incorporate other factors, including patient wishes, quality of life, and life expectancy based on age and comorbidities. The appropriateness of these recommendations for a specific patient may vary depending on these factors and will be best judged by the bedside clinician.

Chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension is one of the few forms of pulmonary hypertension that is surgically curable. It is likely underdiagnosed and must be considered in every patient presenting with pulmonary hypertension to avoid missing the opportunity to cure these patients. This article discusses the epidemiology, risk factors, natural history, diagnosis, and preoperative evaluation of patients with this disorder. Also covered are putative mechanisms for the conversion of acute emboli into fibrosed thrombembolic residua. Mechanical obstruction of the central pulmonary vasculature is rarely the sole cause of the pulmonary hypertension, and a discussion of the small vessel arteriopathy present in these patients is offered. Technical aspects of pulmonary endartectomy and the data supporting its role are discussed, as are the limited data on pulmonary arterial hypertension specific medical therapies for patients deemed noncandidates for the operation.

Multipotent mesenchymal progenitor cells are present in endarterectomized tissues from patients with chronic thromboembolic pulmonary hypertension

Factors contributing to the development of a fibrotic vascular scar and pulmonary vascular remodeling leading to chronic thromboembolic pulmonary hypertension (CTEPH) are still unknown. This study investigates the potential contribution of multipotent progenitor cells and myofibroblasts to the development and progression of CTEPH. Histological examination of endarterectomized tissues from patients with CTEPH identified significant neointimal formation. Morphological heterogeneity was observed in cells isolated from these tissues, including a network-like growth pattern and the formation of colony-forming unit-fibroblast-like colonies (CFU-F). Cells typically coexpressed intermediate filaments vimentin and smooth muscle alpha-actin. Cells were characterized by immunofluorescence and quantitated by fluorescent-activated cell sorting (FACS) for the presence of cell surface markers typical of mesenchymal progenitor cells; cells were >99% CD44(+) CD73(+), CD90(+), CD166(+); >80% CD29(+); 45-99% CD105(+); CD34(-) and CD45(-). Cells were capable of adipogenic and osteogenic differentiation, determined by Oil Red O and Alizarin Red staining, respectively. Additionally, a population of Stro-1(+) cells, a marker of bone marrow-derived stromal cells (4.2%), was sorted by FACS and also capable of adipogenic and osteogenic differentiation. In conclusion, this study is the first to identify a myofibroblast cell phenotype to be predominant within endarterectomized tissues, contributing extensively to the vascular lesion/clot. This cell may arise from transdifferentiation of adventitial fibroblasts or differentiation of mesenchymal progenitor cells. The unique microenvironment created by the stabilized clot is likely a factor in stimulating such cellular changes. These findings will be critical in establishing future studies in the development of novel and much needed therapeutic approaches for pulmonary hypertension.

[Image-guided minimally invasive treatment of pulmonary arterial hypertension due to embolic disease]

OBJECTIVE

Although surgical pulmonary thromboendarterectomy is the treatment of choice for pulmonary hypertension due to chronic thrombotic and/or embolic disease, minimally invasive endovascular techniques such as angioplasty or placement of a metallic stent can provide acceptable results when surgery is not indicated or has been refused by the patient.

PATIENTS AND METHODS

Eight patients (5 men, 3 women; mean age, 62.6 years) were treated. The patients were in New York Heart Association (NYHA) class III or IV and had a mean pulmonary artery pressure of 40 mm Hg and more, a capillary wedge pressure of 15 mm Hg or less, or a Miller index greater than 0.5. In all cases, diagnosis was based on Doppler echocardiography, pulmonary angiography, hemodynamic evaluation, and ventilation-perfusion scintigraphy. All patients received fibrinolytic therapy and underwent angioplasty. A metallic stent was implanted in 3 patients. Follow-up echocardiographic assessment and ventilation-perfusion scans were scheduled at 1, 3, 6, and 12 months.

RESULTS

The procedures were technically successful in all cases. The mean follow-up period was 18.7 months. Minor complications were extrasystoles (3 cases), slight bruising at the site of puncture (1 case), and rectal bleeding that resolved without treatment (1 case). One patient died from an unknown cause 24 hours after the procedure. In all other cases, improvements were noted in NYHA functional class, in hemodynamics demonstrated by echocardiography, and in vascular structure as shown by arteriography and scintigraphy.

CONCLUSIONS

Minimally invasive endovascular interventions can help improve pulmonary arterial hypertension due to chronic thrombotic and/or embolic disease in patients for whom medical or surgical treatment is not possible.

Role of NT-proBNP and 6MWD in chronic thromboembolic pulmonary hypertension

BACKGROUND

This study aims to evaluate the role of NT-proBNP and six minute walking distance (6MWD) in the pre- and post-operative assessment of subjects undergoing pulmonary endarterectomy (PEA) for chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

Subjects undergoing PEA between August 2004 and July 2006 were assessed at baseline and 3 months post-operatively with resting haemodynamics, NT-proBNP and 6MWD.

RESULTS

A number of 111 subjects underwent surgery, of which 102 were included. 15 subjects died before their 3 month assessment. Non-survivors had significantly worse preoperative NT-proBNP and 6MWD (4728 pg/mL vs 1863 pg/mL, p=0.001, 182.4 m vs 263.5 m, p=0.001). Taking pre-operative cut-off values of 1200 pg/mL for NT-proBNP and 345 m for 6MWD, both tests had high negative predictive value for predicting mortality (97.3% and 100%, respectively). Amongst survivors, peri-operative changes in NT-proBNP and 6MWD correlated with changes in total pulmonary resistance (TPR) (r=0.49, p<0.001 and r=-0.46, p<0.001). Post-operatively, both NT-proBNP and 6MWD also correlated with mPAP (r=0.65, p<0.001 and r=-0.50, p<0.001) and PVR (r=0.63, p<0.001 and r=-0.47, p<0.001). The ability of NT-proBNP to predict persistent pulmonary hypertension was significantly confounded by age, but not gender, BMI or renal function.

CONCLUSIONS

Pre-operative evaluation with NT-proBNP and 6MWD helps risk-stratify patients prior to PEA. Post-operatively, both markers correlate with changes in disease burden and right ventricular function. These results suggest that both NT-proBNP and 6MWD offer effective 'bedside' tools for the long term follow up of patients with CTEPH.

Chronic thromboembolic pulmonary hypertension

The description of organized thrombus in major pulmonary arteries can be found in autopsy reports dating back to the late nineteenth and early twentieth centuries. Not until the 1950s was the antemortem diagnosis and clinical syndrome of chronic thrombotic obstruction of the major pulmonary arteries better characterized. The first surgical attempt to remove the adherent thrombus from the vessel wall occurred in 1958. This operation provided the conceptual foundation for the distinction between acute and chronic thromboembolic disease of the pulmonary vascular bed, and established that an endarterectomy, and not an embolectomy, would be necessary if a surgical remedy for this disease was to be successful.

Intravenous Epoprostenol in Inoperable Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Pulmonary thromboendarterectomy may be a cure for patients with chronic thromboembolic pulmonary hypertension (CTEPH) with proximal obstruction. Conversely, short-term prognosis is poor for inoperable CTEPH patients with distal obstruction. Vascular remodeling lesions can be found in lungs of patients with CTEPH. Little is known about epoprostenol therapy in inoperable distal CTEPH patients.

METHODS

We conducted a retrospective analysis of 27 consecutive patients with inoperable distal CTEPH, who were in New York Heart Association Functional Class (NYHA FC) III (n = 20) or IV (n = 7) and treated with long-term intravenous epoprostenol.

RESULTS

Before epoprostenol initiation (baseline), 6-minute walk distance (6MWD) was 265 +/- 117 m, right atrial pressure 13 +/- 5 mm Hg, mean pulmonary artery pressure (mPAP) 56 +/- 9 mm Hg, cardiac index (CI) 1.9 +/- 0.3 liters/min/m2, total pulmonary resistance (TPR) 29.3 +/- 7.0 U/m2 and mixed venous oxygen saturation 52 +/- 8%. After 3 months of epoprostenol (n = 23; mean epoprostenol dose 16 +/- 2 ng/kg/min), NYHA FC improved by one class in 11 of 23 patients, 6MWD increased by 66 m (p < 0.0001), and hemodynamics also improved (mPAP: 51 +/- 8 mm Hg, p = 0.001; CI: 2.3 +/- 0.4 liters/min/m2, p = 0.0003; TPR: 23.0 +/- 5.0 U/m2, p < 0.0001). At last evaluation (n = 18; 20 +/- 8 months), mean dose of epoprostenol was 30 +/- 8 ng/kg/min, NYHA FC was improved in 9 of 18 patients and there was sustained improvement in 6MWD (+46 m, p = 0.03) and hemodynamic parameters. Survival at 1, 2 and 3 years was 73%, 59% and 41%, respectively.

CONCLUSIONS

Long-term treatment with intravenous epoprostenol improves exercise capacity and hemodynamic parameters in patients with inoperable distal CTEPH. Epoprostenol may be used as bridge therapy in CTEPH patients awaiting lung transplantation.

Postoperative management of the patient undergoing pulmonary endarterectomy

The postoperative care of the patient undergoing pulmonary endarterectomy presents challenges that occur not only with other types of cardiac surgery but also with significant respiratory system changes related to alterations in pulmonary blood flow. Postoperative mortality associated with this procedure has declined substantially over the years as a consequence of improved evaluative procedures and selective surgical referral, advances in surgical technique, and an understanding of the unique postoperative complications that may occur. However, postoperative acute lung injury and residual pulmonary hypertension continue to represent major causes of mortality associated with this procedure and represent areas where additional investigative efforts are necessary. Here we describe the unique hemodynamic and respiratory changes that occur in the postoperative pulmonary endarterectomy patient and an evidence-based approach to their optimal management.

Reverse right ventricular remodeling after pulmonary endarterectomy in patients with chronic thromboembolic pulmonary hypertension: Utility of magnetic resonance imaging to demonstrate restoration of the right ventricle

OBJECTIVES

Pulmonary arterial hypertension causes right ventricular remodeling; that is, right ventricular dilatation, hypertrophy, and leftward ventricular septal bowing. We studied the effect of pulmonary endarterectomy on the restoration of right ventricular remodeling in patients with chronic thromboembolic pulmonary hypertension by magnetic resonance imaging.

METHODS

In 17 patients with chronic thromboembolic pulmonary hypertension, before and at least 4 months after pulmonary endarterectomy, and in 12 healthy controls, right ventricular and left ventricular end-diastolic and end-systolic volumes (milliliters) and mass (grams per meter squared) and leftward ventricular septal bowing (1 divided by the radius of curvature in centimeters) were determined by magnetic resonance imaging.

RESULTS

Before pulmonary endarterectomy, right ventricular volumes, left ventricular end-diastolic volume, right ventricular mass, and leftward ventricular septal bowing differed significantly between patients with chronic thromboembolic pulmonary hypertension and healthy control subjects. After pulmonary endarterectomy, pulmonary hemodynamics improved, and right and left ventricular volumes and leftward ventricular septal bowing normalized; right ventricular mass decreased significantly (46 +/- 14 to 31 +/- 9 g x m(-2), P< .0005), but did not completely normalize. The change in total pulmonary resistance correlated with the change in right ventricular ejection fraction (r = 0.50, P < .05), right ventricular mass (r = 0.63, P < .01), and leftward ventricular septal bowing (r = 0.50, P < .05).

CONCLUSIONS

Right ventricular remodeling was observed in patients with chronic thromboembolic pulmonary hypertension and restored almost completely after a hemodynamically successful pulmonary endarterectomy. Magnetic resonance imaging is a valuable tool to evaluate cardiac remodeling and function in patients with chronic thromboembolic pulmonary hypertension, both before and after pulmonary endarterectomy.

Pulmonary endarterectomy

Chronic thromboembolic pulmonary hypertension is a condition that is recognised in an increased percentage of patients. Pulmonary endarterectomy is recognised as being the only curative option for a subgroup of those patients, but anaesthesiologists and intensivists face many challenges in how they manage these patients perioperatively. Ultimately, it is the combination of skills in a multidisciplinary team that leads to a successful procedure and dramatically improves patient's quality of life and life expectancy.

Long-Term Recovery of Exercise Ability After Pulmonary Endarterectomy for Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

The exercise capacity of patients with thromboembolic pulmonary hypertension was investigated to clarify the long-term effects of pulmonary endarterectomy. This capacity was assessed by measuring cardiopulmonary factors during cardiopulmonary exercise testing at the maximal level of exercise and a 6-minute walk test at the submaximal level. Their survival rate was also determined.

METHODS

We conducted a retrospective review of the clinical records of 102 patients who underwent pulmonary endarterectomy (63 women; median age, 53 years).

RESULTS

Eight (7.8%) hospital mortalities were encountered. Three late mortalities due to fulminant hepatitis, breast cancer, and pneumonia in a patient under steroid therapy were unrelated to pulmonary endarterectomy. The actual survival rate including hospital mortalities was 90.9% at 3 years and 84.0% at 5 years. All hemodynamic measurements significantly improved and reached a plateau 1-month after endarterectomy. The cardiopulmonary exercise test at the maximal exercise level revealed that peak oxygen uptake (V(O2)) baseline was 13.8 +/- 3.2 mL/min/kg, and at 1-month was 16.2 +/- 4.2 mL/min/kg (p = 0.0015) and ventilatory response to carbon dioxide production (V(E)-V(CO2)) slope baseline was 46.5 +/- 8.4 mL/min/kg, and at 1-month was 39.9 +/- 7.4 (p = 0.0006), which gradually and significantly improved during the first year after endarterectomy (peak V(O2), 19.9 +/- 3.9 mL/min/kg [p < 0.0001] and V(E)-V(CO2) slope, 33.2 +/- 5.4 mL/min/kg [p <0.0001]). The 6-minute walk test, which reflects the systemic response at the submaximal level of functional capacity, showed that the walking distance gradually and significantly increased for up to 1 year after endarterectomy (baseline, 358 +/- 102 meters [m]; at 1-month, 433 +/- 105 m; and at 1-year, 490 +/- 80 m [p < 0.0001]) and then reached a plateau.

CONCLUSIONS

After pulmonary endarterectomy, the hemodynamic recovery occurred immediately, and the patients' exercise capacity improved during the year. The 6-minute walk test was a good indicator to assess the recovery of exercise capacity.

Outcomes of Pulmonary Endarterectomy Surgery

Chronic thromboembolic pulmonary hypertension has emerged as one of the leading causes of severe pulmonary hypertension. This disease is estimated to occur in approximately 1 to 5% of all patients who have previously developed an acute pulmonary embolism, although the true prevalence is suspected to be much higher. Chronic thromboembolic pulmonary hypertension is characterized by intraluminal thrombus organization, fibrous stenosis, and vascular remodeling of pulmonary vessels. Pulmonary endarterectomy is an operation that is considered curative for thromboembolic pulmonary hypertension and is therefore superior to transplantation for this condition. This article focuses on the surgical outcomes of patients undergoing pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension and discusses the currently known factors that affect survival after this operation.

Mid-term efficacy of beraprost, an oral prostacyclin analog, in the treatment of distal CTEPH: a case control study

BACKGROUND

Prostanoids are a well-established therapy for pulmonary arterial hypertension (PAH), and observational studies suggest their efficacy even in chronic thromboembolic pulmonary hypertension (CTEPH) patients.

OBJECTIVE

To compare the effects of 6 months of treatment with beraprost, an orally-active prostacyclin analog, in patients with distal CTEPH and PAH.

DESIGN

Case-control study.

POPULATION

Sixteen patients with severe pulmonary hypertension (NYHA II-IV), eight with distal CTEPH matched with eight patients with idiopathic PAH for similar effort tolerance.

METHODS

All patients were in stable clinical and hemodynamic condition for 3 months with maximal standard therapy. During the titration phase (4 weeks) beraprost was increased to maximal tolerated dose (mean daily dosage: CTEPH 275 +/- 47 microg, PAH 277 +/- 47 microg) in adjunction of standard therapy, patients were followed-up for 6 months.

MAIN OUTCOME MEASURES

World Heart Organization (WHO) functional class, exercise capacity measured by distance walked in 6 min, and systolic pulmonary pressure (echocardiography), were evaluated at baseline, and at 1-, 3- and 6-month interval.

RESULTS

At 6 months WHO class decreased significantly in both groups (CTEPH from 2.7 +/- 0.6 to 2.0 +/- 0.24, p < 0.05; PAH from 3.0 +/- 0.26 to 2.1 +/- 0.25, p < 0.05), similarly the 6-min walk distance increased significantly from baseline (CTEPH from 312 +/- 31 to 373 +/- 29 m, p < 0.003; PAH from 303 +/- 31 to 347 +/- 29, p < 0.0003). Systolic pulmonary artery pressure showed a trend toward lower value (CTEPH from 85 +/- 7 m to 81 +/- 6 mm Hg, p = NS; PAH from 89 +/- 7 to 82 +/- 5, p = NS). During the observation period we did not have any death. The drug was well-tolerated with minor side-effects.

CONCLUSION

In patients with CTEPH beraprost had similar mid-term clinical and hemodynamic improvements than in patients with PAH.

Outcomes of pulmonary endarterectomy for treatment of extreme thromboembolic pulmonary hypertension

OBJECTIVE

Pulmonary endarterectomy is the operation of choice for thromboembolic pulmonary hypertension. As the largest referral center for thromboembolic pulmonary hypertension in the world, we are frequently asked whether patients with extreme pulmonary hypertension (pulmonary artery systolic pressure >100 mm Hg) can safely undergo this operation with therapeutic benefit.

METHODS

To determine whether patients with pulmonary artery systolic pressures of greater than 100 mm Hg have favorable outcomes after pulmonary endarterectomy, we reviewed the outcomes of 743 patients who underwent this operation between 1999 and 2004. We compared hemodynamic and outcome parameters of 65 patients (group 1: 26 male and 39 female patients; mean age, 49.5 years) who had preoperative pulmonary artery systolic pressures of greater than 100 mm Hg with 678 patients (group 2: 314 male and 364 female patients; mean age, 50.3 years) with preoperative pulmonary artery systolic pressures of less than 100 mm Hg.

RESULTS

Group 1 patients had a greater overall diminution in pulmonary vascular resistance (mean decrease: 926.7 +/- 511.1 vs 546.4 +/- 365.1 dynes x sec x cm(-5), P < .01) and reduction in pulmonary artery systolic pressure (mean decrease: 50.5 +/- 18.7 vs 27.2 +/- 18.6 mm Hg, P < .05), with similar improvement in cardiac output (mean increase: 1.53 +/- 1.47 vs 1.55 +/- 1.58 L/min) compared with values seen in group 2 patients. Although length of hospital stay was similar for the 2 groups, overall perioperative survival was slightly lower in group 1 patients (89.2% [58/65] for group 1 vs 96.5% [654/678] for group 2). Patients with extreme pulmonary hypertension manifest a higher rate of postoperative reperfusion edema, leading to longer days of intubation compared with group 2 patients.

CONCLUSIONS

Pulmonary endarterectomy can be performed safely in patients with severe thromboembolic pulmonary hypertension. The magnitude of preoperative pulmonary artery systolic pressure or pulmonary vascular resistance is not a contraindication for surgical intervention. Indeed, patients with extreme pulmonary hypertension might benefit the most from this operation.

Acute pulmonary embolism: an update on diagnosis and management

Pulmonary embolism (PE) is a common problem. Given the significant overlap of symptoms and signs between the presentation of PE and acute coronary syndromes, it becomes clear that cardiologists must be familiar with the diagnosis and treatment of PE. The critical issue is always to consider PE in the diagnosis of chest pain. It is then important to determine the likelihood of the diagnosis. For patients at moderate-to-high risk, helical CT provides a rapid and noninvasive diagnostic tool. Several other imaging studies are also available including ventilation/perfusion (V/Q) scan, magnetic resonance imaging, and pulmonary arteriography. Echocardiography can also provide valuable prognostic information. Several biomarkers including the d-dimers, troponins, and natriuretic peptides may provide additional information. The cornerstone of treatment includes anticoagulation. For patients with massive or submassive PE, thrombolysis and embolectomy should be considered. Finally, both primary and secondary prevention are critical to the long-term health of the patient.

Qualidade de vida antes e após tromboendarterectomia pulmonar: resultados preliminares

INTRODUÇÃO: A hipertensão pulmonar secundária a tromboembolismo crônico é uma doença grave, debilitante e associada a elevada mortalidade. A tromboendarterectomia pulmonar é o tratamento de escolha para o seu tratamento. OBJETIVO: Avaliar o impacto da tromboendarterectomia sobre a qualidade de vida dos pacientes com hipertensão pulmonar secundária a embolia crônica de pulmão através do questionário SF-36 Health Survey. MÉTODO: O questionário SF-36 Health Survey foi aplicado em treze pacientes antes da cirurgia e ao menos 3 meses depois da tromboendarterectomia. RESULTADOS: Sete indivíduos do sexo feminino e seis do masculino, com idade média de 45,7± 18,3 anos, submetidos a tromboendarterectomia completaram o estudo. Todos os domínios do questionário, com exceção da saúde mental, melhoraram no pós operatório. CONCLUSÃO: A tromboendarterectomia pulmonar produziu uma melhora significativa na qualidade de vida dos pacientes.

Paediatric pulmonary vascular disease

Pulmonary vascular disease comprises any congenital or acquired pathology of the intrinsic pulmonary vessels with the unique feature of pulmonary arteries carrying unsaturated blood and pulmonary veins carrying oxygenated blood. Pulmonary hypertension (PH) ensues when pulmonary vascular disease affects at least 50% of the capillary resistance vessels, i.e. pulmonary pre-acinar and intra-acinar arteries (so-called pre-capillary PH), or when pressure in the pulmonary venous system distal to the capillaries rises above a mean of 15 mmHg (so-called post-capillary PH). PH is defined by a mean pulmonary arterial pressure above 25 mmHg at rest. Vasoconstriction, remodelling and thrombosis of small pulmonary arteries lead to an increase in pulmonary vascular resistance. The consequence is failure of the afterload-intolerant right ventricle. In this review, pulmonary vascular disease in children will be addressed according to the 2003 World Health Organisation (Venice) classification of PH.

Pulmonary thromboendarterectomy surgery

Considerable progress has been made over the past decade in understanding the etiology, prevalence, natural history, and therapeutic approach to chronic thromboembolic pulmonary hypertension. Pulmonary endarterectomy is now widely recognized as the definitive treatment for chronic pulmonary hypertension resulting from thromboembolic disease. This article focuses on the surgical treatment of chronic thromboembolic pulmonary hypertension.

Chronic Thromboembolic Pulmonary Hypertension: Pre- and Postoperative Assessment with Breath-hold MR Imaging Techniques

PURPOSE

To evaluate the potential of breath-hold magnetic resonance (MR) imaging techniques in morphologic and functional assessment of patients with chronic thromboembolic pulmonary hypertension (CTEPH) before and after surgery.

MATERIALS AND METHODS

Thirty-four patients with CTEPH were examined before and after pulmonary thromboendarterectomy (PTE). For morphologic assessment, contrast material-enhanced MR angiography was used; for assessment of hemodynamics, velocity-encoded gradient-echo sequences and cine gradient-echo sequences along the short axis of the heart were performed. Contrast-enhanced MR angiography was compared with selective digital subtraction angiography (DSA) for depiction of central thromboembolic material and visualization of the pulmonary arterial tree. Functional analysis included calculation of left and right ventricular ejection fractions and peak velocities, net forward volumes per heartbeat, and blood volume per minute in the left and right pulmonary arteries and ascending aorta. Flow measurements were compared with invasively measured mean pulmonary arterial pressure (MPAP) and pulmonary vascular resistance (PVR) measurements. Nonparametric Wilcoxon and sign tests were used for statistical analysis.

RESULTS

MR angiography revealed typical findings of CTEPH (intraluminal webs and bands, vessel cutoffs, and organized central thromboemboli) in all patients. It depicted pulmonary vessels up to the segmental level in all cases. For subsegmental arteries, DSA revealed significantly more patent vessel segments than did MR angiography (733 versus 681 segments, P <.001). MR angiography revealed technical success of surgery in 33 of 34 patients. Patients had reduced right ventricular ejection fractions and pulmonary peak velocities that significantly increased after PTE (P <.001 for both). Right ventricular ejection fraction had good correlation with PVR (r = 0.6) and MPAP (r = 0.7). The postoperative decrease in MPAP correlated well with the increase in right ventricular ejection fraction (r = 0.8). Postoperatively, there was complete reduction of a preoperatively existing bronchosystemic shunt volume in 33 of 34 patients.

CONCLUSION

Breath-hold MR imaging techniques enable morphologic and semiquantitative functional assessment of patients with CTEPH.

Chronic thromboembolic pulmonary hypertension

During the past 2 decades, there has been a steady rise in the number of patients with chronic thromboembolic pulmonary hypertension (CTEPH) undergoing surgery and in the number of programs worldwide dedicated to the diagnosis and management of this patient population. This article discusses the natural history and clinical presentation of CTEPH, the evaluation of patients for pulmonary thromboendarterectomy, and the outcomes following surgery, along with a brief review of the procedure as performed at the University of California, San Diego.

Surgical Treatments/Interventions for Pulmonary Arterial Hypertension

While considerable advances have been achieved in the medical treatment of pulmonary arterial hypertension (PAH) over the past decade, surgical and interventional approaches continue to have important roles in those patients for whom medical therapy is unavailable or has been unsuccessful. These techniques include pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension, thoracic transplantation, and atrial septostomy. This chapter will provide evidence-based recommendations for the selection and timing of surgical and interventional treatments of PAH for physicians involved in the care of these complex patients.

Pulmonary thromboendarterectomy almost 50 years after the first surgical attempts

With increased experience in preoperative evaluation, surgical approach and postoperative care of chronic thromboembolic pulmonary hypertension, pulmonary thromboendarterectomy can be performed with an acceptably low risk of death. Most patients, even those in a very compromised state, have excellent, long lasting results.