Single photon emission computed tomography in chronic thromboembolic pulmonary hypertension

Background and objective: The management of chronic thromboembolic pulmonary hypertension (CTEPH) is largely dependent on the extent of obstruction in the pulmonary arteries. Planar perfusion scans are commonly used to quantify perfusion defects in CTEPH patients. However, planar scans typically under‐represent the extent of vascular obstruction in CTEPH. We conducted this study to test the hypothesis that SPECT lung perfusion scans are more accurate than planar scans for determining the location and extent of perfusion defects in patients with CTEPH. Methods: Planar ventilation scans, planar and SPECT perfusion scans were performed preoperatively in patients undergoing pulmonary thromboendarterectomy for treatment of CTEPH. Two clinical experts independently documented the segmental anatomy of the vascular obstructions by reviewing clinical records, pulmonary and CT angiograms, and surgical specimens. A nuclear medicine expert documented the segmental anatomy of the perfusion defects observed by planar and SPECT scans independently. Results: Clinical/pathological evaluation disclosed 241 obstructed and 99 unobstructed lung segments in 17 patients. Sensitivity for detecting obstructed segments was significantly higher for SPECT than for planar scanning (63.5 ± 3.1% vs 42.7 ± 3.2%, respectively; P < 0.01). Specificities of SPECT and planar scanning were not significantly different (62.6 ± 4.8% vs 76.8 ± 4.2%, respectively; P = 0.092). Conclusions: The SPECT is more sensitive than planar perfusion scanning for identifying obstructed segments in CTEPH. However, even SPECT under‐represents the true extent of the vascular occlusions in CTEPH.     

Prostacyclin therapy before pulmonary thromboendarterectomy in patients with chronic thromboembolic pulmonary hypertension

OBJECTIVES: The continuous IV administration of prostacyclin improves pulmonary hemodynamics and prognosis in patients with primary pulmonary hypertension. We investigated whether the administration of prostacyclin therapy to patients before they undergo pulmonary thromboendarterectomy ameliorates pulmonary hypertension in patients with the most severe form of chronic thromboembolic pulmonary hypertension (CTEPH). METHODS: Of the 33 patients with CTEPH who were candidates for pulmonary thromboendarterectomy, 12 patients with severe pulmonary hypertension (pulmonary vascular resistance, > 1,200 dyne. s. cm(-5)) received IV prostacyclin prior to undergoing pulmonary thromboendarterectomy. Right heart catheterization and plasma brain natriuretic peptide (BNP) measurements were repeated at baseline, immediately before surgery, and 1 month after surgery. RESULTS: During a mean (+/- SEM) follow-up period of 46 +/- 12 days, the IV administration of prostacyclin resulted in a 28% decrease in pulmonary vascular resistance (1,510 +/- 53 to 1,088 +/- 58 dyne. s. cm(-5); p < 0.001) before surgery. Prostacyclin therapy markedly decreased plasma BNP level (547 +/- 112 to 188 +/- 30 pg/mL; p < 0.01), suggesting improvement in right heart failure. Pulmonary thromboendarterectomy caused a further reduction of pulmonary vascular resistance (302 +/- 47 dyne. s. cm(-5)) and plasma BNP levels (60 +/- 11 pg/mL) compared to each preoperative value (p < 0.05). Operative mortality rates were relatively low (8.3%) in patients with the most severe form of CTEPH. CONCLUSION: The IV administration of prostacyclin caused beneficial hemodynamic effects in patients with severe CTEPH and may serve as pretreatment for patients undergoing pulmonary thromboendarterectomy.     

Chronic thromboembolic and pulmonary arterial hypertension share acute vasoreactivity properties

BACKGROUND: Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are the major classes of pulmonary hypertensive disorders according to the World Health Organization; both lead to right heart failure and death. A better understanding of disease mechanisms has led to the suggestion that the thromboembolic and nonthromboembolic types of pulmonary hypertension may share pathophysiologic features. We therefore compared acute vasoreactivity and proximal pulmonary artery compliance in patients with PAH and CTEPH during the initial diagnostic heart catheterization. METHODS: Right heart catheterization using a flow-directed Swan-Ganz catheter was performed in patients with CTEPH (n = 22) and PAH (n = 35). Pulmonary hemodynamics were assessed at baseline, during the inhalation of 40 ppm of nitric oxide, and 30 min after the inhalation of 10 mug of iloprost. To assess the proximal pulmonary artery compliance, the pulse pressure (PP) [systolic-diastolic pressure] and the fractional PP (PPf) [divided by the mean pressure] were calculated. RESULTS: Both vasodilators produced similar hemodynamic improvement, and the difference between CTEPH and PAH was not significant. The baseline PP and PPf did not vary between the two groups. CONCLUSION: Patients with PAH and CTEPH show similar acute vasoreactivity to inhaled nitric oxide and iloprost, and have similar pulmonary artery compliance. These findings support the presence of some shared pathophysiologic pathways in both disorders and may lead to therapeutic implications in patients with inoperable CTEPH.     

Chronic thromboembolic pulmonary hypertension: anticoagulation and beyond

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CT scan findings in chronic thromboembolic pulmonary hypertension: predictors of hemodynamic improvement after pulmonary thromboendarterectomy

STUDY OBJECTIVES: The aim was to correlate CT scan findings with hemodynamic measurements in patients who had undergone pulmonary thromboendarterectomy (PTE) and to evaluate whether CT scan findings can help to predict surgical outcome.Patients and method: Sixty patients who underwent PTE and preoperative helical CT scanning were included. Preoperative and postoperative hemodynamics were correlated with preoperative CT imaging features. RESULTS: The diameter of the main pulmonary artery (PA) and the ratio of the PA and the diameter of the ascending aorta correlated with preoperative mean pulmonary artery pressure (PAP) [r = 0.42; p < 0.001; and r = 0.48; p < 0.0001, respectively]. There was a significant correlation of subpleural densities with preoperative pulmonary vascular resistance (PVR) [r = 0.44; p < 0.001] and of the number of abnormal perfused lobes with preoperative PAP (r = 0.66; p < 0.0001) and PVR (r = 0.76; p < 0.0001). Postoperative PVR correlated negatively with the presence and extent of central thrombi (r = -0.36; p = 0.007) and dilated bronchial arteries (p = 0.03) seen on preoperative CT scans. Sixty percent of patients (3 of 5 patients) without visible central thromboembolic material on CT scans had an inadequate hemodynamic improvement in contrast to 4% of patients (2 of 51 patients) with central thrombi (p = 0.003). Preoperative PVR (r = 0.31; p = 0.018) and the extent of abnormal lung perfusion (r = 0.37; p = 0.007) and of subpleural densities (r = 0.32; p = 0.017) were positively correlated with postoperative PVR. CONCLUSIONS: In patients with thromboembolic pulmonary hypertension, CT scan findings can help to predict hemodynamic improvement after PTE. The absence of central thrombi is a significant risk factor for inadequate hemodynamic improvement.     

Chronic thromboembolic pulmonary hypertension: A review of current practice

Pulmonary artery hypertension is a complex and multi-faceted disease process with numerous etiologies. Chronic thromboembolic pulmonary hypertension (CTEPH) is an underdiagnosed and highly treatable form of pulmonary hypertension. In this disease, certain patients with a history of pulmonary thromboembolic disease go on to develop elevated pulmonary artery pressures, shortness of breath, and progressive right heart failure. This article will review the epidemiology, pathophysiology, diagnosis and treatment of CTEPH with a review of pulmonary thromboendarterectomy surgery.     

Diagnosis with helical CT and echocardiography of patients with suspected chronic thromboembolic pulmonary hypertension

Chronic Thromboembolic Pulmonary Hypertension (CTEPH) is a serious disease with a very high mortality after variable periods of time. Early diagnosis of CTEPH is critical because thromboendarterectomy can improve survival, hemodimamics and functional capacity. Based on our experience we have performed a review of diagnostic techniques. Echocardiography, pulmonary angiography, fiberoptic angioscopy, helical CT an MRI. For each diagnostic procedure we have analysed its accuracy, invasiveness and easiness of use. We conclude that currently the most useful techniques are echocardiography (to asses pulmonary hypertension), and helical CT which is a good alternative to pulmonary angiography and can detect very specific findings such as dilatation of central pulmonary arteries, eccentric localized thrombi and mosaic attenuation of the pulmonary parenchyma. Even more accurate findings can be expected by the use of multislice CT, which could allow to asses the degree of narrowing of the pulmonary vessels and bronchial circulation.     

Noncalcified pulmonary hamartomas: computed tomography enhancement patterns with histologic correlation

The objective of this study was to correlate contrast-enhanced computed tomography images of noncalcified hamartomas with histologic specimens to find specific computed tomography enhancement patterns. Over 4 years, 30 noncalcified hamartomas were surgically resected. Enhanced computed tomography images of these hamartomas were reviewed and correlated with histologic findings. Contrast-enhancing septa were present in 24 of 30 hamartomas (80%). Five hamartomas (15%) showed a nonspecific enhancement pattern. The presence of an air bronchogram was a rare finding (5%). Comparison between computed tomography images and pathologic specimens showed that areas with less enhancement corresponded to cartilagineus tissue, and enhancing septa corresponded to loose connective tissue within the cartilagineus core. The rare finding of an air bronchogram corresponded to bronchial epithelium within cartilagineus tissue.     

Dynamic ECG changes after thromboendarterectomy in a patient with chronic thromboembolic pulmonary hypertension and C protein deficiency

A case of a 44-year-old-man with chronic thromboembolic pulmonary hypertension (PH) and C-protein deficiency, with a history of previous acute pulmonary embolism is presented. The ECG showed negative T waves in leads: II, III, aVF and V(1)-V(6). The follow-up echocardiography revealed severe PH with the right ventricular systolic pressure (RVSP) - 95-100 mm Hg, markedly enlarged right ventricular end-diastolic diameter (RVEDD), and decreased left ventricular end-diastolic diameter (LVEDD). The patient was in NYHA III/IV class. He was referred for pulmonary thromboendarterectomy. Three months after thromboendarterectomy echocardiography showed marked reduction of RVEDD, increased LVEDD, RVSP - 50-55 mm Hg. The 3 months follow-up ECG showed normalisation to positive T waves. The patient was in NYHA class I and he stayed on the anticoagulation therapy.     

Chronic thromboembolic pulmonary hypertension: clinical picture and surgical treatment.

Chronic, major vessel thromboembolic pulmonary hypertension (CTEPH), is an uncommon condition which, in the past, was an autopsy curiosity. Advances in diagnostic approaches, surgical techniques and postoperative management have transformed this disorder into a potentially curable form of pulmonary hypertension. The predominant symptom is unexplained dyspnoea on exertion. In patients with this complaint, CTEPH should be considered. Numerous pitfalls exist along the diagnostic path. Perfusion lung scans point toward the diagnosis, but often underestimate the extent of central arterial obstruction. Pulmonary angiography is the key diagnostic procedure, but the many patterns of thrombus organization-recanalization require a base of experience for proper interpretation. Criteria for selection of patients for surgery are evolving, but assurance of thrombus accessibility to surgery is critical. Surgical thromboendarterectomy bears no resemblance to acute pulmonary embolectomy. Recognition of thrombus (versus normal intima), meticulous dissection and a bloodless surgical field are essential for adequate restoration of pulmonary vascular patency. Multiple complications may arise postoperatively, and detailed attention to these is required for patient survival. With a co-ordinated, multi-specialty team effort, however, haemodynamic and clinical outcomes have been rewarding and persist long-term. Surgical mortality should steadily decline with such a co-ordinated effort, as well as earlier diagnosis and advances in surgical and postoperative management techniques.     

Physical activity in incident patients with pulmonary arterial and chronic thromboembolic hypertension

Introduction

The cardinal symptom of pulmonary hypertension (PH) is dyspnea on exertion, leading to decreased activity in daily living. The aim of this study was to analyze daily physical activity in incident patients with arterial or chronic thromboembolic PH (PAH/CTEPH) and to investigate its correlation with pulmonary hemodynamics, symptoms, exercise capacity, and other outcomes.

Methods

Incident patients with PAH/CTEPH had a 1-week activity assessment by the arm-worn accelerometer SenseWear within − 3 months/+ 2 weeks of the diagnostic right heart catheterization (RHC) and baseline assessments including 6-minute walking distance (6MWD). Activity was correlated to RHC data at rest and exercise and to other outcomes.

Results

Thirty-nine PH-patients (24 PAH, 15 CTEPH, 23 females, 65(54;73) years, mean pulmonary artery pressure (mPAP) 38(30;46) mmHg, cardiac output (CO) 5.2(4.6;6.3) l/min, 6MWD 458(300;593) m) were included. 64% had a sedentary lifestyle ( < 5000 steps/day), 26% were moderately active (5000–9999 steps/day), and 10% were active. In a multivariate stepwise regression analysis including age, gender, 6MWD and hemodynamics at rest and during exercise (heart rate, mPAP, stroke volume), the 6MWD was the only independent predictor of steps/day (B = 16.8 (95% CI 11.6–22.0), p < 0.001).

Conclusion

Daily physical activity as steps/day assessed in incident patients with PAH/CTEPH did not well correlate with invasive hemodynamics at rest or during exercise, but very well with the 6MWD. Whether daily activity assessments provide additional information to simple walk distance on risk factor profiles during follow-up in patients with PAH/CTEPH remains to be clarified.

     

Chronic thromboembolic pulmonary hypertension associated with endomyocardial fibrosis of the right ventricle

Chronic thromboembolic pulmonary hypertension is a rare sequela to an acute untreated or recurrent pulmonary embolism. The mechanisms that underlie the failure to resolve the thrombus are still uncertain. As most patients are not diagnosed until a relatively late stage, little is known about the course of their illness. We report the case of a 51-year-old woman who had previously been diagnosed with and operated on for endomyocardial fibrosis of the right ventricle and who developed chronic thromboembolic pulmonary hypertension several years later.     

Thoracic research scholarship 1988: pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension at the University of California, San Diego

At the University of California, San Diego pulmonary thromboendarterectomy (PTE) has emerged as an effective measure in the treatment of chronic thromboembolic pulmonary hypertension. Unresolved emboli become organized by incorporation into the vascular wall and may form strictures, webs, bands and/or membranous occlusions and cause pulmonary hypertension refractory to medical treatment. When pulmonary vascular resistance exceeds 300 dyn.sec.cm-5 and the vascular wall changes are located to begin at or proximal to the lobar artery level, surgery is indicated. The operation is performed using cardiopulmonary bypass, deep hypothermia and periods of circulatory arrest. The dissection of each segmental artery is carried out in the media layer from separate incisions in the right and left pulmonary artery at the level of the pericardial flexion. Pulmonary reperfusion edema may complicates the postoperative course, and pulmonary hemorrhage, respiratory insufficiency necessitating prolonged ventilatory support and secondary multi organ failure are main causes of hospital mortality. Between October 1984 and September 1988 103 patients with a mean age of 50 +/- 16 years underwent PTE. Consequently, pulmonary vascular resistance could be reduced from 788 +/- 370 to 299 +/- 150 dyn.sec.cm-5 and cardiac index increased from 2.0 +/- 0.6 to 3.2 +/- 0.8 l/min-m2. Hospital mortality was 11.7% (12/103 patients). Thus, pulmonary thromboendarterectomy effectively reduces pulmonary hypertension at an acceptable low risk. The results indicate that patients should be diagnose and referred for surgery as early as possible.