Chronic Thromboembolic Pulmonary Hypertension

By Peter F. Fedullo, MD

Print This | TOC | Previous | Next

---

Surgical Selection, Surgical Approach, and Outcome

The intent of the extensive evaluation process is to establish the need for surgical intervention, determine the surgical accessibility of the chronic thromboemboli, and estimate the risk of thromboendarterectomy as well as the anticipated hemodynamic outcome in the individual patient. The majority of patients who undergo thromboendarterectomy exhibit a pulmonary vascular resistance > 300 dyneásácm^-5. At centers reporting their experience with thromboendarterectomy surgery, preoperative pulmonary vascular resistance is typically in the range of 700 to 1,100 dyneásácm^-5 (Table 2).^18-29 Patients without substantially altered pulmonary hemodynamics, such as those with involvement of one main pulmonary artery, those with unusually vigorous lifestyle expectations, and those who live at altitude, may also be considered for surgery to alleviate the exercise impairment associated with their high dead-space and minute ventilatory demands. Surgery is also offered to patients with normal pulmonary hemodynamics or only mild levels of pulmonary hypertension at rest who develop significant levels of pulmonary hypertension with exercise.

Table 2ÑPublished Results for Pulmonary Thromboendarterectomy Since 1997*

Year	Author	Location	Patients, No.	Preop PVR, dyneásácm-5	Postop PVR, dyneásácm-5	Mortality, %
1997	Nakajima18	Japan	30	937 ± 45	299 ± 16	13.3
1997	Mayer19	Germany	32	967 ± 238	301 ± 151	9.3
1998	Gilbert20	Baltimore, MD	17	~700 ± 200	~170 ± 80	23.5
1998	Miller21	Philadelphia, PA	25	NA	NA	24
1999	Dartevelle22	France	68	1,174 ± 416	519 ± 250	13.2
1999	Ando23	Japan	24	1,066 ± 250	268 ± 141	20.8
2000	Jamieson24	San Diego, CA	457	877 ± 452	267 ± 192	7
2000	Mares25	Austria	33	1,478 ± 107à	975 ± 93à	9.1
2000	Mares25	Austria	14	1,334 ± 135à	759 ± 99à	21.4
2000	Rubens26	Canada	21	765 ± 372	208 ± 92	4.8
2000	DÕArmini27	Italy	33	1,056 ± 344	196 ± 39¤	9.1
2001	Tscholl28	Germany	69	988 ± 554	324 ± 188	10.1
2001	Masuda29	Japan	50	869 ± 299#	344 ± 174#	18
*Preop = preoperative; postop = postoperative; PVR = pulmonary vascular resistance, mean ± SD; NA=not available.
Estimate derived from a graph.
àResults expressed as pulmonary vascular resistance index.
¤Data in 23 patients at 3-month follow-up.
#34 patients by sternotomy, 16 patients by thoracotomy.

An absolute criterion for surgery is the presence of accessible chronic thrombi. Current surgical techniques allow removal of organized thrombi whose proximal extent is in the main and lobar arteries and, depending on surgical skill and experience, those involving the proximal segmental arteries. The presence of comorbid conditions that may adversely affect perioperative mortality or morbidity as well as long-term survival must also be considered before surgical referral. Advanced age and the presence of collateral disease do not represent absolute contraindications to thromboendarterectomy, although they do influence risk assessment. The one exception to this guideline is the presence of severe underlying obstructive or restrictive parenchymal lung disease. In this circumstance, thromboendarterectomy may result in hemodynamic improvement but often does not ameliorate the gas exchange consequences of the underlying parenchymal lung disease.

The only therapeutic alternative for patients not deemed to be candidates for thromboendarterectomy is lung transplantation. Preliminary results suggest that selected patients may benefit from chronic epoprostenol therapy.³⁰

The details of the surgical procedure itself are beyond the scope of this review but have been comprehensively reviewed elsewhere.²⁴ However, several features of the procedure should be emphasized. First, although a thoracotomy approach has been utilized in the past, the standard approach now involves median sternotomy, cardiopulmonary bypass, and periods of hypothermic circulatory arrest. A sternotomy approach provides access to the central pulmonary vessels of both lungs and avoids the potential for disruption of the extensive bronchial collateral circulation and pulmonary adhesions that may develop following pulmonary artery obstruction. Second, the procedure is a true thromboendarterectomy and not an embolectomy. The neointima must be meticulously dissected away from the native intima, and considerable surgical experience with this procedure is required to identify the correct operative plane (Fig 3).

Figure 3. Specimen obtained at the time of pulmonary thromboendarterectomy. Note fibrotic appearance with extensions into multiple segmental-level pulmonary arteries.

 

In series of patients undergoing thromboendarterectomy since 1996, in-hospital mortality rates as high as 24% have been reported (Table 2).^18-29 In experienced, larger-volume programs with a programmatic commitment to the care of these patients, however, mortality rates of 4 to 7% are typical (Fig 4). The major causes of death, beyond those associated with other open-heart cardiac procedures, are reperfusion pulmonary edema and residual pulmonary hypertension.^18,31 For survivors, both the short-term and long-term hemodynamic outcomes are favorable. The pulmonary artery pressure and pulmonary vascular resistance are dramatically reduced and at times normalized. In published series, the mean reduction in pulmonary vascular resistance has approximated 70% and a pulmonary vascular resistance in the range of 200 to 350 dyneásácm^-5 can be achieved.^18-29 A corresponding improvement in right ventricular function determined by echocardiography, gas exchange, exercise capacity, and quality of life has also been reported.^32-35 Most patients initially in New York Heart Association functional Class III or IV before surgery return to Class I or II postoperatively and are able to resume normal activities.

Figure 4. Number of surgically treated cases and deaths in 1,389 patients undergoing thromboendarterectomy at University of California, San Diego Medical Center between 1986 and 2001.

 

Lifelong anticoagulant therapy is strongly recommended after thromboendarterectomy. A number of patients in whom anticoagulation was discontinued or maintained at a subtherapeutic level experienced recurrent thromboembolism, and several of them required a second thromboendarterectomy.

---

Print This | TOC | Previous | Next

3300 Dundee Road • Northbrook, Illinois 60062-2348 • (847) 498-1400 • (800) 343-2227
Copyright ©1999-2008 American College of Chest Physicians. All Rights Reserved.
ACCP Privacy Policy | ACCP Web Site Terms of Use