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Incidence of Atrial Fibrillation after Extrapleural Pneumonectomy versus Pleurectomy in patients with Malignant Pleural Mesothelioma

Friday, August 29, 2008

Source: Interactive Cardiovascular and Thoracic Surgery

The two most common surgeries for the treatment of pleural mesothelioma are extrapleural pneumonectomy (EPP) and pleurectomy-decortication (PD). Both are considered radical surgery and both have been associated with significant postoperative complications, with EPP being the more radical procedure and the one more likely to have serious side effects. One of the side effects seen in both procedures is atrial fibrillation (AF), a type of irregular heartbeat where the upper chambers of the heart (the atria) quiver and beat in a chaotic fashion instead of properly contracting in a controlled and efficient manner. AF can increase a person’s chance of developing a blood clot that can travel to the brain and cause a stroke, or even death, so it’s clearly a serious condition to watch out for. Even as contemporary surgical techniques have reduced the gross number of surgical complications, side effects are always possible, so research is being conducted to investigate the conditions under which they can occur.

An article was recently published in the journal Interactive Interactive Cardiovascular and Thoracic Surgery that compared the incidence of atrial fibrillation in mesothelioma patients after EPP and P/D. The study was designed to discover which procedure was more likely to cause AF and what co-factors were most likely to affect this causation.

Overview of the Study

To investigate the incidence of atrial fibrillation following extrapleural pneumonectomy and pleurectomy, the authors of the article conducted a retrospective analysis of patients who were treated for pleural mesothelioma between November 2001 and October 2003. 130 patients were initially identified, but the study only looked at 127 of them because three patients had experienced atrial fibrillation at some point prior to the surgeries under consideration. The study specifically looked at the number of patients that experienced atrial fibrillation within three days of surgery and it used the patients who did not experience AF as the control group. The authors conducted a statistical analysis that utilized and reported on single variable causation factors, as well as a multivariate analysis that reported on the likelihood of AF when a number of interacting variables were considered as co-factors.

Results

127 patients were specifically included in the study results. 70 patients underwent an EPP and 57 underwent pleurectomy-decortication. Within the total patient population, the study sample included 45 patients who experienced atrial fibrillation within three days of surgery, leaving a control sample of 82 patients. 36 patients in the study sample underwent EPP, while only 9 underwent P/D.

The authors compared the two groups along a number of standard classification variables, but the only statistically significant, single variable differences between the two groups were incidence of AF and cell histology. Along with the higher incidence of postop AF, the EPP group also had a larger number of epithelial mesothelioma cases as compared to the P/D group. There is no indication that cell histology has any relationship to likelihood of atrial fibrillation, but EPP was found to be a definite risk factor for AF.

Other factors that appeared to contribute to the likelihood of AF were EPP + patient age and pre-existing structural abnormalities in the heart. The authors found that patients older than 65 had a significantly higher risk of AF after undergoing EPP than did patients who were younger than 65 that also underwent EPP. When studying echocardiogram results from a subgroup of the patient population, they found that those patients whose results suggested structural abnormalities were also at increased risk of atrial fibrillation. However, EPP was still the primary risk factor.

Deploying both univariate and multivariate analyses of the following variables and patient characteristics did not reveal any significant increase in risk: gender, affected side, preoperative heart rate, heart disease or preoperative use of beta-blockers.

Conclusion

Extrapleural pneumonectomy is the one of the most important techniques in the treatment of pleural mesothelioma because it allows the most extensive resection of malignant tissue, so limiting post-op complications is clearly an important factor for patient health. Contemporary surgical methods have definitely reduced the incidences of associated side effects, but this study has clearly shown that the nature of the procedure itself be a risk factor for atrial fibrillation. The authors suggest that the “increased pulmonary pressure and right atrial stress after complete removal of one lung causes right heart distention in the early postoperative phase” and that this could “increase the risk of arrhythmias” in patients who undergo the procedure. Because of this, they recommend that steps be taken to prepare for AF or that measures be enacted to limit the heart stress associated with EPP.

Labels: epp, mesothelioma, pd, treatments

posted by Belluck & Fox at 3:51 PM
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