Expanding Knowledge of Lung Volume Reduction

Regional ventilation and distribution of emphysema - a quantitative comparison

The distribution of ventilation and emphysema throughout the lung was compared in 20 emphysematous patients who were candidates for lung volume reduction surgery. Ventilation distribution among 1.6-cm-high stripe regions was obtained in supine position by planar gamma camera scintigraphy after inhalation of technegas. Results from nine healthy subjects provided normal stripe count rates. Patient count rates were expressed as the difference from predicted normal stripe count rate (DeltaSVI). Thus, DeltaSVI is a relative index of abnormal ventilation. Emphysema was assessed quantitatively by a density mask method on corresponding slices of high resolution computed tomography (HRCT). The results show that in the majority of patients, there is a highly significant relationship between the degree of stripe hypoventilation and the amount of distribution of emphysema, but in some patients no such relationship is found. We speculate that the distribution of airway obstruction not necessarily follows the distribution of emphysema, which could explain the lack of concordance between ventilation and emphysema distribution in some patients. We conclude that ventilation scintigraphy contains complementary information to lung HRCT.

Sustained improvements in dyspnea and pulmonary function 3 to 5 years after lung volume reduction surgery

OBJECTIVES

To determine long-term survival rates of patients who underwent lung volume reduction surgery (LVRS) for emphysema and the factors associated with longer survival, and to evaluate levels of perceived dyspnea and health-related quality of life (HRQL) after a follow-up period of 3 to 5.5 years.

DESIGN

Retrospective observational study.

SETTING

Academic medical center

METHODS

Telephone and postal surveys were used to obtain patient dyspnea scores and HRQL scores. Hospital databases and state registries were searched to determine patient survival and pulmonary function.

RESULTS

Of 54 patients undergoing LVRS, 29 patients (18 men and 11 women) were available for follow-up, which ranged from 36 to 66 months (mean +/- SE, 51 +/- 1.5 months). There was significant sustained improvement in modified Medical Research Council scores compared to pre-LVRS: 2.19 +/- 0.19 vs 2.88 +/- 0.14 (p = 0.0000). Eleven of 22 patients demonstrated an increase in all three Mahler baseline dyspnea index grades of at least one level. Baseline body mass index (BMI) and post-LVRS length of stay (LOS) were significantly associated with survival: survivor vs deceased baseline BMI, 24.2 +/- 0.6 vs 21.4 +/- 0.5 (p = 0.002), and post-LVRS LOS, 15.4 +/- 1.7 days vs 28.7 +/- 5.3 days (p = 0.015). Compared to pre-LVRS, 20 patients with mean follow-up time of 45 months demonstrated significant sustained improvements in FEV(1) percentage of predicted (31.4 +/- 2.1% vs 39.8 +/- 3.5%, p = 0.038), total lung capacity percentage of predicted (136 +/- 4% vs 122 +/- 3%, p = 0.0004), and residual volume percentage of predicted (237 +/- 14% vs 172 +/- 11%, p = 0.0001). Patient HRQL measured using the Dartmouth Primary Care Co-operative Quality of Life questionnaire was more favorable than that reported in aged-care settings. Caregiver burden scale scores indicate caring for a recipient of LVRS carries similar burden to that for caring for individuals with other chronic illnesses.

CONCLUSIONS

In this population, a majority of the LVRS patients survived for >/= 3 years. Among survivors, dyspnea and lung function benefits were seen. Baseline BMI and postoperative LOS were significantly associated with survival.

Patients at high risk of death after lung-volume-reduction surgery

BACKGROUND

Lung-volume-reduction surgery is a proposed treatment for emphysema, but optimal selection criteria have not been defined. The National Emphysema Treatment Trial is a randomized, multicenter clinical trial comparing lung-volume-reduction surgery with medical treatment.

METHODS

After evaluation and pulmonary rehabilitation, we randomly assigned patients to undergo lung-volume-reduction surgery or receive medical treatment. Outcomes were monitored by an independent data and safety monitoring board.

RESULTS

A total of 1033 patients had been randomized by June 2001. For 69 patients who had a forced expiratory volume in one second (FEV1) that was no more than 20 percent of their predicted value and either a homogeneous distribution of emphysema on computed tomography or a carbon monoxide diffusing capacity that was no more than 20 percent of their predicted value, the 30-day mortality rate after surgery was 16 percent (95 percent confidence interval, 8.2 to 26.7 percent), as compared with a rate of 0 percent among 70 medically treated patients (P<0.001). Among these high-risk patients, the overall mortality rate was higher in surgical patients than medical patients (0.43 deaths per person-year vs. 0.11 deaths per person-year; relative risk, 3.9; 95 percent confidence interval, 1.9 to 9.0). As compared with medically treated patients, survivors of surgery had small improvements at six months in the maximal workload (P= 0.06), the distance walked in six minutes (P=0.03), and FEV1 (P<0.001), but a similar health-related quality of life. The results of the analysis of functional outcomes for all patients, which accounted for deaths and missing data, did not favor either treatment.

CONCLUSIONS

Caution is warranted in the use of lung-volume-reduction surgery in patients with emphysema who have a low FEV1 and either homogeneous emphysema or a very low carbon monoxide diffusing capacity. These patients are at high risk for death after surgery and also are unlikely to benefit from the surgery.