Clinical Status

The evaluation of potential LVRS candidates starts with a complete history, physical examination, and routine laboratory studies. Important clinical issues include patient age, smoking history, bronchitic disease component, nutritional status, level of disability, extent of systemic steroid requirements, cardiac status, presence of pulmonary hypertension, presence of other significant lung diseases, and presence of other significant medical diseases.

The age of the patient appears to be an important prognostic factor. While at Columbia Presbyterian Medical Center (CPMC) and other centers, patients over age 80 have successfully undergone LVRS, most studies suggest that patients over the age of 70 face increased perioperative risks, and higher mortality (20,21). In the CPMC experience, patients over age 70 have a predicted 4-yr mortality of more than 60% compared with a 40% mortality under age 70. Most centers do not view age over 70 yr as an absolute contraindication to LVRS, although most suggest that only the most ideal of these elderly patients should be considered for surgery. In this regard, in order to be enrolled in the NETT, patients over age 70 must have an FEV1 greater than 15% of predicted.

Most patients with emphysema are elderly. However, younger patients (under age 55) occasionally present with significant emphysema. Many of these patients have the | -1 antitrypsin deficiency variant. Most of these have a lower lobe predominance of disease, as opposed to the upper lobe predominance seen in most cases of emphysema. Patients with | -1 antitrypsin deficiency have undergone LVRS. Results in these patients have been less impressive, with benefits of shorter duration than in other patients. In these younger patients, LVRS may simply be a "bridge" to transplantation, as Cooper initially suggested.

The link between cigarette smoking and development of emphysema has been well documented (22,23). Active cigarette smokers have a much more marked yearly reduction in FEV1 than nonsmokers or former smokers (24). In addition, cigarette smokers face higher postoperative risks of bronchitic exacerbation, atelectasis, or pneumonia (25). Most centers require that potential LVRS candidates stop smoking at least 4 mo prior to evaluation. Patients in the NETT undergo regular serum cotinine testing. If not using nicotine-preventive products, plasma cotinine levels must be less than 31.7 ng/mL. If using nicotine preventive products arterial carboxyhemoglobin levels must be less than 2.5%.

Most patients with COPD have the bronchitic form of the disease (26). LVRS is not appropriate for these patients. Many patients with emphysema have a bronchitic component. The greater the bronchitic component, the less likely LVRS will be of benefit. In addition, the greater the bronchitic component, the higher the risk of postoperative complications, including atelectasis, pneumonia, and respiratory failure. For these reasons, a history of recurrent bronchial infections or significant daily sputum production is viewed as a contraindication to LVRS.

Nutritional status is a concern in patients with advanced emphysema (27). Studies suggest that more than 20% of outpatients with significant COPD, andmore than 50% of hospitalized COPD patients are malnourished (28,29). Nutritional status also correlates with mortality risk. Emphysema patients below 80% ofideal body weight face 3-yr mortality rates over 30%. Despite enteral and parenteral modalities aimed at improving nutritional parameters, these patients remain severely functionally limited. In the CPMC experience, malnourished patients undergoing LVRS have had significantly higher morbidity and mortality. Most centers exclude patients with unplanned weight loss over 10% of usual weight in the 90 d prior to evaluation. Whereas patients with significant emphysema are rarely overweight, obesity also confers a higher postoperative risk of morbidity and mortality. Therefore, NETT patients must have a body mass index (BMI) < 31.1 kg/m2 in men or < 32.3 kg/m2 in women.

Level of disability and degree of limitation are critically important issues. Because results of LVRS are impossible to guarantee, and benefits of LVRS vary and are not permanent, and also because the procedure carries major risks, candidates for LVRS must be severely limited. Although severity of limitation usually correlates with the severity of reduction in FEVb there is considerable variability (30). Different patients with the same level of FEV1 can have very different degrees of limitation and very different degrees of dyspnea. Therefore, there is general agreement that dyspnea indices and quality-of-life assessments are important parts of any LVRS evaluation. Some potential LVRS candidates may be too limited to undergo the procedure. If, after completing pulmonary rehabilitation, patients are still unable to walk more than 140 m in 6 min, most investigators do not believe they are appropriate LVRS candidates.

Patients with severe emphysema are at risk of developing pulmonary hypertension from a combination of loss of the pulmonary capillary bed and disturbances in gas exchange (31,32). Some authors have suggested that in certain patients, LVRS can actually improve pulmonary hemodynamics (33). However, this is an area of major concern to pulmonolgists and thoracic surgeons caring for these patients (34-36). Whereas surgeons aim to resect areas of lung with decreased vascular perfusion on CAT scan or perfusion lung scan, a certain amount of capillary bed is invariably removed. Thus, the potential of worsening pulmonary hypertension exists, especially iftoo much functioning lung is removed. If peak systolic pulmonary artery pressure (PAP) on echocardiogram evaluation is equal to or over 45 mmHg, right-heart catheterization is suggested. If this degree of systolic pulmonary hypertension (or mean PAP r 35 mmHg) is found on catheterization, the patient is not a candidate for LVRS. Screening echocardiograms may also give information about left-ventricular function and valvular problems that could require cardiac consultation before making decisions regarding LVRS eligibility.

Most patients with emphysema are former cigarette smokers and are also at risk for coronary artery disease (31). Because of their respiratory limitations, typical anginal symptoms may not be present. A clinical history suggesting unstable angina, a myocardial infarction within 6 mo, an S3 gallop or a history of CHF within 6 mo, a left-ventricular ejection fraction < 45%, syncope, or significant ventricular ectopy may be viewed as possible contraindications for the procedure and require cardiac clearance before proceeding. Many of these patients may not be able to complete a treadmill exercise study. Therefore, most centers suggest performing dobutamine radionuclide cardiac scanning in these patients. A positive study would require cardiac consultation before deciding whether LVRS remains an option.

Cardiopulmonary exercise testing helps delineate cardiac, pulmonary, and deconditioning components of a patient's generalized disability (37,38). It plays a role in outlining the degree of limitation, and helps set up an appropriate pulmonary rehabilitation program (see Chapter 2). In the NETT, one of the main study outcomes is maximum exercise performance, and repeat cardiopulmonary exercise studies are the crucial part of that evaluation. There is no question about the importance of these tests in ongoing research studies of LVRS. However, at present, the ultimate role of cardiopulmonary exercise testing in clinical LVRS evaluations remains somewhat unclear.

Patients facing LVRS obviously are severely limited. Any other pulmonary or medical problems could adversely effect surgical and long-term results. Significant kyphoscoliosis, bronchiectasis, or pleural or interstitial lung disease would preclude surgery. Evidence of a systemic disease or malignancy that is expected to compromise survival would be a contraindication to the procedure. Uncontrolled hypertension with systolic blood pressure > 200 mmHg or diastolic blood pressure >110 mmHg could significantly increase operative risks, and would have to be better controlled before proceeding with LVRS. Dependence on high-dose systemic steroids raises additional concerns, including the risk of osteoporosis, which could compromise postoperative recovery (39). In addition, because emphysema is not a steroid-responsive disease, significant systemic steroid dosing may suggest a greater asthmatic or bronchitic component. The NETT eliminates patients using more than 20 mg of prednisone daily.

At this time, prior lung resection surgery, including prior LVRS, is viewed as a contraindication because procedures performed in this setting have been complicated and usually poorly tolerated. Adhesions from prior procedures can dramatically increase air leak and bleeding risks. At CPMC and other centers, unilateral LVRS has been performed in patients with old pleural disease on the contralateral side, and in patients status post prior contralateral lung resection including prior unilateral LVRS. Whereas the procedure can be safely performed in this setting, results are generally not as good as with the bilateral LVRS procedure (40,41).

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