In this study, we report our contemporary indications, risk factors, and outcomes for pericardiectomy. In this modern, 16-year experience, we found intermediate and long-term outcomes differed dramatically by etiology with post-radiation patients continuing to have a dismal outcome. Moreover, hypoalbuminemia and hyperbilirubinemia were predictors of adverse short and long-term outcomes. Additionally, although the etiologic distribution of our patients has changed over time, with a decreasing number of post-radiation patients, short and long-term survival appears to be similar regardless of the era of operation.
Previous studies have reported widely ranging outcomes following pericardiectomy, with perioperative mortality ranging from 5.6% to as high as 11%.[1
] In our series, we report an in-hospital mortality of 7.1% which is similar to several modern series.[1
] As has been previously reported,[3
] we found dramatically different intermediate and long-term survival depending on etiology. When stratified by etiology, on both univariate and multivariable analysis, post-radiation pericarditis was associated with significantly lower 1, 5, and 10-year survival than idiopathic or postoperative pericarditis. Additionally, although it did not reach statistical significance, postoperative pericarditis tended to be associated with lower survival than idiopathic pericarditis but better survival than post-radiation pericarditis. These findings are consistent with previous studies suggesting poor long-term survival for patients with post-radiation pericarditis.[1
] The outcomes of radiation-induced pericarditis are so dismal, that some have suggested pericardiectomy is futile for this patient population.[6
] However, our series demonstrates acceptable perioperative mortality with a 1-year survival over 50%, despite a higher percentage requiring CPB, suggesting that at least half of these patients may benefit from this operation. Therefore, in carefully selected patients with radiation-induced pericarditis we still offer pericardiectomy.
On multivariable analysis, post-radiation pericarditis was significantly associated with an increased hazard of intermediate and long-term mortality. Not surprisingly, the need for cardiopulmonary bypass was also associated with increased 30-day mortality, likely denoting either a more difficult pericardiectomy or a sicker patient requiring a concomitant procedure. Interestingly, our models found increasing bilirubin and hypoalbuminemia to also be predictive of mortality. Increasing bilirubin is likely a surrogate for the degree of heart failure caused by severe pericarditis. Such heart failure likely results in cardiac cirrhosis secondary to a combination of decreased hepatic perfusion and increased hepatic congestion. Several previous studies have found increased total bilirubin to be predictive of mortality after heart transplantation and thus its association with increased mortality after pericardiectomy is not surprising.[11
] Similarly, several previous reports have suggested that hypoalbuminemia may be a powerful predictor of malnutrition and overall poor health in the cardiac surgery population.[13
] Thus patients with severe hypoalbuminemia have increased perioperative and long-term mortality.
The impact of pericardial calcification on outcomes is controversial. Although some studies have identified pericardial calcification as a significant risk factor for increased mortality, several have not.[8
] In the largest US series to date, Bertog et al.[3
] did not find pericardial calcification to be associated with increased mortality. In our study, calcific pericarditis was not a risk factor for either early or late morality.
In analyzing our case mix over the study period, we found that post-radiation pericarditis has comprised a decreasing percentage of our population over time. Although there has certainly been an increase in the number of cases of postoperative pericarditis in our series and others,[8
] we also observed a decrease in the absolute numbers of radiation-induced pericarditis requiring pericardiectomy. Whether this represents an actual decrease in the incidence of post-radiation pericarditis, secondary to increasingly narrow fields of radiation and better shielding, or whether this represents some type of selection or referral bias warrants further investigation. Interestingly, this change in case mix has not resulted in a change in overall survival.
The optimal surgical approach is controversial. While some authors have suggested that complete pericardiectomy is best performed via a median sternotomy,[17
] others have argued in favor of a left anterolateral thoracotomy.[4
] In our series, a median sternotomy was utilized in over 90% of cases and a total pericardiectomy was performed in over 95% of the cases. In the largest series to date, Chowdhury et al.[4
] found that total pericardiectomy was associated with increased survival compared to partial pericardiectomy. In their series, the predominant surgical approach was an anterolateral thoracotomy. Thus, as others have suggested, it is not the surgical approach but rather the extent of pericardiectomy that is important.[1
] We agree with previous reports that a total pericardiectomy should be performed whenever possible since it is associated with improved outcomes and prevents recurrence.[4
] Therefore, although surgical approach is largely a matter of surgeon preference, we favor a median sternotomy as it facilitates excellent exposure to adequately perform a complete pericardiectomy.[3
] Moreover, in cases requiring a concomitant procedure, a median sternotomy permits easy access for cardiopulmonary bypass. Although many of our patients required cardiopulmonary bypass, this was mostly secondary to a concomitant procedure. Thus we agree with others who have suggested that cardiopulmonary bypass is not necessary for a total pericardiectomy.[4
] However, dense epicardial scarring can result in incidental ventriculotomies and thus preparation for emergent cardiopulmonary bypass is prudent.
Our study is a retrospective study and despite our efforts to control for confounding data and selection bias, it is not possible to control for all confounders. Additionally, as a single-center study, our sample size is relatively small and thus susceptible to a type II error. Our findings should be considered in light of these limitations.
Although our cardiac surgery database is extensive, some variables are not captured well. In particular, tuberculosis skin test results cannot be extracted in a retrospective fashion. Tuberculosis is an uncommon etiology of pericarditis in the Western world. None of our patients showed clinical evidence for tuberculosis and the final pathology of all the patients was negative for acid fast staining organisms and granulomatous inflammation. However, the absence of tuberculosis skin testing results is a limitation.
In conclusion, although survival varies significantly by etiology, pericardiectomy continues to be a safe operation for constrictive pericarditis. Post-radiation pericarditis, hypoalbuminemia, and hyperbilirubinemia are significant risk factors for decreased long-term survival. Finally, while the etiologic spectrum has changed over time, these changes have not affected outcomes.