| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2006;82:630-636
© 2006 The Society of Thoracic Surgeons
a Department of Cardiovascular Surgery, National Cardiovascular Center
b Department of Cardiology, National Cardiovascular Center
c Department of Thoracic Surgery, Fujita Health University
Accepted for publication March 27, 2006.
* Address correspondence to Dr Ogino, Department of Cardiovascular Surgery, National Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan (Email: hogino{at}hsp.ncvc.go.jp).
 |
Abstract |
|---|
 Top Abstract IntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
METHODS: Between 1995 and 2004, 88 patients underwent surgery for CTEPH. Mean pulmonary artery pressure and pulmonary vascular resistance were 46 mm Hg (range, 23 to 70 mm Hg) and 986 dynes · sec–1 · cm–5 (298 to 2,231 dynes · sec–1 · cm–5). The pulmonary artery lesion was proximally located in 51 patients, subsegmental in 34 patients, and peripheral in 3 patients. Pulmonary endarterectomy was performed using cycles of 15-minute intermittent circulatory arrest followed by 10-minute reperfusion at 16°C to 18°C.
RESULTS: The median durations of circulatory arrest, cardiopulmonary bypass, and surgery were 58, 217, and 355 minutes, respectively. Percutaneous extracorporeal membrane oxygenation was used in 8 patients (9.1%) who had difficulty being weaning from cardiopulmonary bypass. Three recent patients for whom this was performed promptly were weaned and survived. There were 7 hospital deaths (8.0%, including 6 30-day deaths) from pulmonary bleeding in 2 patients, residual pulmonary hypertension in 3, rupture of bulla in 1, and empyema in 1. In the 81 survivors, mean pulmonary artery pressure and pulmonary vascular resistance fell significantly after surgery (p < 0.0001, each case). Age more than 60 years was a risk factor for hospital mortality on multivariate analysis. Although distal pulmonary artery disease including subsegmental and peripheral lesions was not a significant risk factor for mortality, it did influence patient recovery: the frequency of percutaneous extracorporeal membrane oxygenation was higher and hemodynamic improvement less pronounced in patients with distal disease. The actuarial survival rate was 90.7% at 3 years and 86.4% at 5 years. None of the patients have suffered recurrence. The event-free rate was 97.1% at 3 years and 93.5% at 5 years. Of the 68 patients surviving for more than 1 year after surgery, 67.6% were successfully weaned from home oxygen therapy and 13.2% required only occasional use of oxygen.
CONCLUSIONS: Pulmonary endarterectomy can be safely performed with relatively low mortality and favorable prognosis with long-term survival, although it should be performed carefully for patients with distal disease.
|
Introduction |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
|
Patients and Methods |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
|
|
Before 2001, an inferior vena cava filter was routinely inserted before surgery [8]. However, since 2001, it has been used in only limited patients at risk of pulmonary embolism due to deep vein thrombosis in the major veins. Postoperatively, anticoagulation therapy was performed with intravenous low-molecular-weight heparin for the first week followed by oral warfarin therapy with a target international normalized ratio of around 2.0. Normally, postoperative cardiac catheterization and pulmonary arteriography were performed 1 month after surgery to determine pulmonary artery pressure and cardiac output.
Data Collection and Statistical Analysis
Medical records were reviewed. Continuous variables are expressed as the mean ± SD or median (range), and categorical variables as percentages. Follow-up was 100% complete. We retrospectively reviewed the overall outcome of pulmonary endarterectomy and investigated risk factors for early mortality using multivariate logistic regression analysis. Statistical analysis was performed using Statview (SAS Institute, Cary, North Carolina) statistical software, with p values less than 0.05 considered significant. Student's t test was used to compare outcomes for proximal and distal disease. Kaplan-Meier estimates were used to calculate survival and event-free rates.
|
Results |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
There were 7 in-hospital deaths (8.0%), including 6 operative (30-day) deaths: 2 due to pulmonary bleeding, 3 due to residual pulmonary hypertension, 1 due to rupture of bulla, and 1 due to empyema. Five patients (71.4%) had distal pulmonary artery disease, except for 2 patients with proximal disease in the early era (1995, 1997). One of these early patients was critically ill and underwent surgery on an emergent basis. Recent mortality rate, since 2000, has improved to 4.8%, compared with 15.3% before 2000 (p=0.095). In the 81 survivors, the mean pulmonary artery pressure fell significantly from 45.2 ± 8.6 mm Hg before to 18.6 ± 7.3 mm Hg after surgery (p< 0.0001). Pulmonary vascular resistance also improved significantly from 1,028 ± 400 dynes · sec–1 · cm–5 to 320 ± 215 dynes · sec–1 · cm–5 (p < 0.0001). In the 8 patients (9.1%) with severe preoperative tricuspid regurgitation due to pulmonary hypertension, tricuspid annuloplasty was performed, using Kay's method in 3 patients and DeVega's technique in 5 patients. With their results included, tricuspid regurgitation was improved postoperatively: before surgery it was grade IV (severe) in 13, grade III (moderate) in 23, grade II (slight) in 19, grade I (mild) in 10, and absent in 1, whereas after surgery it was grade III in 3, grade II in 11, grade I in 36, and absent in 16 patients.
On long-term follow-up, 1 patient each died of breast cancer, sudden death during hemodialysis for chronic renal failure, and pneumonia (total, 3.7%). The actuarial survival rate was 90.7% at 3 years and 86.4% at 5 years (Fig 3). No patients suffered recurrence of CTEPH; the rate of freedom from related events, which included pneumothorax in 1 patient, congestive right heart failure in 1 patient, and acute pulmonary embolism in 1 patient, was 97.1% at 3 years and 93.5% at 5 years (Fig 4). Postoperative improvement in NYHA class was clearly observed (Fig 5). Of the 68 patients surviving for more than 1 year after surgery, 67.6% were successfully weaned from home oxygen therapy and 13.2% required oxygen only occasionally, during sleep or exercise. Only 19.1% have remained on home oxygen therapy, and even for them, the amount of oxygen required has been considerably reduced (Fig 5).
|
|
|
|
|
Comment |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
In the present retrospective study, the overall outcome of 8.0% early mortality and 3.7% late mortality was considered satisfactory, given that the surgery involved is difficult and evolving. Since 2000, mortality has improved to 4.8%, even though higher-risk patients with distal disease are now increasingly accepted for surgery. On postoperative evaluation of the survivors, mean pulmonary artery pressure and pulmonary vascular resistance also significantly declined. These favorable surgical results are similar to those reported by the San Diego group [5, 6]. However, our results differed from previous results in certain respects. In the present series, the incidences of distal disease classified as type III or IV were higher than those reported by the San Diego group. Their 500-patient cohort included 37.4% type I patients, 49% type II, 12% type III, and 1.6% type IV patients [6], and 86.4% had proximal disease that was easily accessible. In our series, 58.0% of patients had proximal disease, whereas the other 42.0% had distal disease, an incidence much higher than that reported by the San Diego group of 13.6%.
One of the reasons for this may be a difference between Japan and the United States in frequency of acute pulmonary embolism. In the United States, approximately 600,000 people suffer from this condition each year. It is estimated that 90% of them survive, and 0.1% to 0.2% have recurrent emboli and CTEPH [5]. In Japan, acute pulmonary embolism has been reported to occur in fewer than 4,000 people per year [9], less than one tenth the incidence in the United States. The incidence of deep vein thrombosis is also estimated to be much lower in Japan, although a recent increase due to Westernization of the Japanese diet has been reported. This large difference in incidence is believed to be due to a racial difference in blood coagulation between Caucasians and Japanese [9]. Correspondingly, the prevalence we found of type I disease including fresh thrombi, was lower than that reported by the San Diego group: only about 20% of the 52.0% of patients with proximal disease, or 10.4% of all patients, were classified as type I in our series. That is less than one third the incidence noted by the San Diego group (37.4%). In CTEPH, vascular obstruction is caused by two mechanisms: (1) direct occlusion of the vessel lumen, and (2) induction of secondary endothelial changes including cellular hyperplasia, webbing, and incomplete clot remodeling [4]. The incidence of CTEPH caused by the first mechanism may be lower in Japanese patients. As a result, a larger number of difficult cases with distal disease were included in our series. Our surgical approach may have been too aggressive, in view of our limited surgical experience; we have thus far encountered only one twentieth the number of patients treated by the San Diego group. We need to establish our own appropriate indications for such high-risk surgery based on our present growing surgical experience.
A previous study found that the largest risk factor for hospital mortality remains the degree of operability, as assessed by pulmonary vascular resistance [5]. There was a difference in outcome in that study between patients with pulmonary vascular resistance less and those with resistance greater than 1,000 dynes · sec–1 · cm–5. A statistical study also demonstrated that severe hemodynamic disease with pulmonary vascular resistance greater than 1,100 dynes · sec–1 · cm–5 and mean pulmonary artery pressure greater than 50 mm Hg is associated with a high probability of operative mortality [10]. Another retrospective study found that patient age and clinical deterioration of pulmonary hypertension are preoperative factors related to hospital mortality [11]. In the present study, age greater than 60 years was a significant risk factor for hospital mortality on multivariate analysis. Six of our 7 patients suffering hospital death were more than 60 years of age, and 2 of the patients were 72 years old.
This type of surgery involves deep hypothermia and prolonged CPB, which can adversely affect organ function throughout body, especially that of the lungs. Prolonged respiratory care including high positive airway pressure is also needed in critically ill patients after surgery. Furthermore, most elderly persons tend to have some impairment of pulmonary function and fragility of pulmonary arteries and lung tissue. Chronic thromboembolic pulmonary hypertension surgery might thus be too invasive for them. In the present series, 2 patients died of pulmonary bleeding, 1 of rupture of bulla and 1 of empyema. This finding differs from the San Diego series, in which the majority of hospital deaths were due to residual pulmonary hypertension and reperfusion injury [5, 6]. The San Diego experience showed that the outcome is determined by the operative classification of thromboembolic disease [4–6]. In our series, the mortality rate of patients with distal disease was higher than that of patients with proximal disease, though the difference between groups was not significant (p = 0.126), probably because 2 patients with proximal disease died early (1995 and 1997) in our series. However, as expected, there were differences in the frequency of use of ECMO and postoperative improvement in hemodynamics between the two groups.
In patients with CTEPH, functional tricuspid regurgitation tends to develop owing to long-standing severe pulmonary hypertension, which induces dilatation of the right ventricle and tricuspid annulus. Right ventricular function also deteriorates with severe pulmonary hypertension, resulting in progressive right heart failure. The presence of these changes can significantly affect the outcome of CTEPH surgery. Menzel and coworkers [7] and the San Diego group [12] do not recommend simultaneous performance of tricuspid annuloplasty with pulmonary endarterectomy, since functional tricuspid regurgitation improved in 70% of patients with large reduction of pulmonary artery pressure after successful pulmonary endarterectomy. We found similar reductions in severity of tricuspid regurgitation. However, the remaining 30% of patients in the San Diego group had persistent, unresolved tricuspid regurgitation due to residual pulmonary hypertension, even after surgery. There was a trend toward longer hospital stay for these patients. Patients with persistent severe tricuspid regurgitation had a 12-fold higher incidence of atrial fibrillation than those exhibiting improvement of tricuspid regurgitation. Menzel and colleagues [7] have published similar results. No significant predictors of residual tricuspid regurgitation were found in either group [7, 12]. However, in the San Diego group, distal thromboembolic disease, mainly type III, was more prevalent among patients with persistent severe tricuspid regurgitation.
We also encountered such patients with more pronounced tricuspid regurgitation, of grade III or IV, due to distal disease. Since pulmonary endarterectomy would be difficult to perform in these patients, residual pulmonary hypertension tends to persist in them. In this study, tricuspid annuloplasty was performed using suture techniques in 8 such high-risk patients, in whom tricuspid regurgitation was dramatically reduced, enabling smooth recovery. We encountered two interesting high-risk patients with distal disease and severe pulmonary hypertension, who were weaned successfully from CPB without ECMO after effective tricuspid annuloplasty, even with severe (above systemic) residual pulmonary hypertension. In these patients, cardiac output increased considerably, with remarkable improvement in hemodynamics and symptoms, although no significant reduction in pulmonary artery pressure was found. We therefore recommend tricuspid annuloplasty for high-risk patients with severe pulmonary hypertension due to distal pulmonary artery disease. In our recent patients, tricuspid ring annuloplasty has been performed to prevent recurrence of tricuspid regurgitation, and we recommend this procedure for high-risk CTEPH patients.
A further unique feature of our series is that ECMO was used to assist circulation when patients were critically ill postoperatively as a result of residual pulmonary hypertension or pulmonary bleeding. There can be some increase in pulmonary artery resistance after surgery due to effects of CPB, hypothermia, and reperfusion injury of the lungs. In high-risk patients with severe pulmonary hypertension due to distal disease, weaning from CPB is difficult in the presence of hypotension and hypoxia. This situation may be associated with serious pulmonary (airway) bleeding due to residual pulmonary hypertension. Weaning becomes much more difficult if hypoxia worsens. Use of ECMO to assist circulation is thus reasonable, as it involves both heart and lung and maintains adequate systemic circulation and oxygenation. Early in our series, it was used in 3 patients with some delay, because it was the only means of keeping the patients alive. In contrast, for the 5 recent patients requiring it, ECMO was promptly performed. Four of these patients were weaned successfully and 3 survived, although two 72-year-old patients died. One of them, a 72-year-old woman, had surgical bleeding and required reexploration several times for hemostasis during ECMO. Her pulmonary function deteriorated with pulmonary bleeding and pneumonia, resulting in hospital death, although she was weaned once from ECMO. The other, a 72-year-old man, who failed to be weaned, had pulmonary artery reocclusion due to fresh thrombi, because heparin was not used to prevent surgical bleeding during the 24-hour period after commencement of ECMO. During that time, ECMO flow was 4 L/min, and close to systemic flow, thereby reducing that in the native pulmonary arteries. Subsequently, thrombus formation occurred in these arteries. Reexploration to remove the thrombi proved too invasive for survival.
We recommend prompt use of ECMO for critical patients who cannot be weaned from CPB owing to residual pulmonary hypertension. In these cases, patients should be carefully monitored for surgical bleeding under heparin use or thrombus formation under reduced pulmonary artery circulation. In patients with an inferior vena cava filter, venous cannulation through the femoral vein to the right atrium might be difficult. In our experience, this was possible in most patients, although it failed in 1. We have tried other methods of treatment including preoperative intravenous prostacyclin [13], an orally active prostacyclin analogue [14], and meticulous postoperative respiratory care using high positive end expiratory pressure and recruitment [15] and nitric oxide inhalation [16].
In our experience, which featured a learning curve for surgery, in at least 2 patients who died of residual pulmonary hypertension due to distal disease and 1 patient in whom ECMO was used without hemodynamic improvement, the surgery should have been refrained. Clearly, patients with peripheral (type IV) lesions should not undergo pulmonary endarterectomy. However, it may be difficult to diagnose type IV lesions preoperatively only by pulmonary arteriography. Furthermore, in patients with type III disease, the indications for surgery are still somewhat controversial. Some patients have type III lesions resembling type IV disease, while others have type III lesions resembling type II disease. Particularly in the former case, it is difficult based on pulmonary arteriography alone to determine whether surgery can be safely performed. Although we have attempted assessment by intravascular ultrasound, this was not accurate enough for decision-making concerning surgery. Endoscopic evaluation is recommended, but it is also not sufficient. We therefore wish to stress that high pulmonary vascular resistance without gross changes proximally on pulmonary arteriography signifies secondary vasculopathy, an inoperable change and a degree of postoperative pulmonary hypertension that would likely hinder recovery, as noted in a previous report [5].
Limitations
The number of patients in this study might not have been large enough for accurate determination of factors predictive of mortality. The period of the study was also too long for the number of patients included, with an average of fewer than 16 patients per year. We have had a significant learning curve in our intraoperative and postoperative management as well as our surgical techniques.
In conclusion, pulmonary endarterectomy can be performed safely with relatively low mortality, hemodynamic improvement, and satisfactory long-term prognosis, although it should be performed carefully for patients with distal disease.
|
Member and Individual Subscriber Access to the Online Annals |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
Society members and non-members alike who do not know their CTSNet user name and password should follow the link "Forgot your user name or password?" that appears below the boxes where you are asked to enter this information when you try to gain full-text access. Your user name and password will be e-mailed to the e-mail address you designate.
In lieu of the above procedure, if you have forgotten your CTSNet username and/or password, you can always send an email to CTSNet via the feedback button from the left navigation menu on the homepage of the online Annals or go directly to http://ats.ctsnetjournals.org/cgi/feedback.
We hope that you will view the online Annals and take advantage of the many features available to our subscribers as part of the CTSNet Journals Online. These include inter-journal linking from within the reference sections of Annals' articles to over 350 journals available through the HighWire Press collection (HighWire provides the platform for the delivery of the online Annals). There is also cross-journal advanced searching, eTOC Alerts, Subject Alerts, Cite-Track, and much more. A listing of these features can be found at http://ats.ctsnetjournals.org/help/features.dtl.
We encourage you to visit the online Annals at http://ats.ctsnetjournals.org and explore.
|
References |
|---|
|
TopAbstractIntroductionPatients and MethodsResultsCommentMember and Individual Subscriber...References |
|---|
This article has been cited by other articles:
|
|
 |
|
  M. Berman, S. Tsui, A. Vuylsteke, A. Snell, S. Colah, R. Latimer, R. Hall, J. E. Arrowsmith, J. Kneeshaw, A. A. Klein, et al. Successful extracorporeal membrane oxygenation support after pulmonary thromboendarterectomy. Ann. Thorac. Surg., October 1, 2008; 86(4): 1261 - 1267. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. H. Freed, B. M. Thomson, S. S.L. Tsui, J. J. Dunning, K. K. Sheares, J. Pepke-Zaba, and D. P. Jenkins Functional and haemodynamic outcome 1 year after pulmonary thromboendarterectomy Eur. J. Cardiothorac. Surg., September 1, 2008; 34(3): 525 - 530. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. G. Corsico, A. M. D'Armini, I. Cerveri, C. Klersy, E. Ansaldo, R. Niniano, E. Gatto, C. Monterosso, M. Morsolini, S. Nicolardi, et al. Long-term Outcome after Pulmonary Endarterectomy Am. J. Respir. Crit. Care Med., August 15, 2008; 178(4): 419 - 424. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Matsuda, H. Ogino, K. Minatoya, H. Sasaki, N. Nakanishi, S. Kyotani, J. Kobayashi, T. Yagihara, and S. Kitamura Long-term recovery of exercise ability after pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension. Ann. Thorac. Surg., October 1, 2006; 82(4): 1338 - 1343. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
