Discussion
The COPPS trial was designed to assess the efficacy and safety of colchicine for the primary prevention of the PPS. This study is an important step ahead in the series of randomized trials addressing important issues in the management of pericardial diseases, designed and conducted by Massimo Imazio. Colchicine is efficacious, inexpensive, and safe medication proven for the treatment and prevention of pericarditis. The exact mechanism of colchicine action is not fully understood. Most of the pharmacological effects of colchicine on cells involved in inflammation appear to be related to its capacity to disrupt microtubules.[10] Colchicine inhibits the process of microtubule self-assembly by binding b-tubulin with the formation of tubulin–colchicine complexes. This action takes place either in the mitotic spindle or in the interphase stage, thus colchicine inhibits the movement of intercellular granules and the secretion of various substances. By this mechanism, colchicine is able to inhibit various leucocytes functions, and this effect should be the most significant for the anti-inflammatory action. Moreover, colchicine shows a preferential concentration in leucocytes and its peak concentration may be more than 16 times the peak concentration in plasma. This seems to be related to its therapeutic effect.
In the COPPS study, colchicine significantly reduced the incidence of the PPS and its related complications providing evidence for the first time that pharmacological prevention of the PSS is possible and safe. Most of the PPS events (85% of all PPS) occurred in the first month, and thus a preventive treatment with colchicine for the first 4 weeks following surgery seems appropriate. No severe side effects were documented, and gastrointestinal side effects were equally distributed between the colchicine and placebo groups. Diarrhoea is relatively common, affecting up to 10% of patients on colchicine treatment for pericarditis. The use of weight-adjusted doses without a loading dose and especially lower doses (i.e.
0.5 mg/day to 0.5 mg bid.) may be a way to reduce this side effect, improving drug compliance. The major study limitation is related to the definition of the PPS since there is no general agreement on this issue. The definition used in the study was taken from the preliminary study from Israel [11] assuming that the diagnosis can be established If at least 2 out of the following 5 diagnostic criteria are present:
- Fever lasting beyond the first post-operative week without evidence of systemic or focal infection
- Pleuritic chest pain
- Friction rub
- Evidence of pleural effusion
- Evidence of new or worsening pericardial effusion
Nevertheless, in the COPPS study, colchicine showed to reduce all 5 above listed major components of the PPS showing a true preventive effect even on several components of the pleuro-pericardial involvement after cardiac surgery.
Although postoperative pericardial effusion is frequent and potentially severe, few randomized, controlled trials have examined treatment for this condition. Recommendation given in the ESC Guidelines [12] to treat postoperative pericardial effusion with NSAIDs was based on the results of the double-blind, placebo-controlled, randomized study by Horneffer et al. [13] applying a 10-day course of ibuprofen or indomethacin. Of 1019 adult patients undergoing cardiac operations during a 14-month period, a diagnosis of postpericardiotomy syndrome was made in 187, and 149 were enrolled in the study. Diagnosis was based on the presence of at least two of the following: fever, anterior chest pain, and friction rub. Drug efficacy was defined as the resolution of at least two of these criteria within 48 hours of drug initiation. Ibuprofen and indomethacin were 90.2% and 88.7% effective, respectively, and both were significantly more effective than placebo (62.5%, p = 0.003). The occurrence of side effects, including nausea, vomiting, renal failure, and fluid retention, was low in all groups (13.1% for ibuprofen, 16.1% for indomethacin, and 16.7% for placebo [p = not significant). Length of hospital stay, incidence of ischemic events, and accumulation of significant pericardial effusions were similar in all groups. The results of this study suggested that both ibuprofen and indomethacin provide safe and effective symptomatic treatment for postpericardiotomy syndrome.
The COPPS trial was designed according to the results of the preliminary prospective, randomized, double-blind study on primary prevention of postpericardiotomy syndrome performed by Finkelstein et al [11] in 163 patients who underwent cardiac surgery in two centres in Israel. On the 3rd postoperative day, the patients were randomly assigned to receive colchicine (1.5 mg/day) or placebo for 1 month. All were evaluated monthly for the first 3 postoperative months for development of postpericardiotomy syndrome. Of the 111 patients who completed the study, 47 (42.3%) received colchicine and 64 (57.7%) placebo. There was no statistically significant difference between the groups in clinical or surgical characteristics. The postpericardiotomy syndrome was diagnosed in 19 patients (17.1%), 5/47 cases (10.6%) in the colchicine group and 14/64 (21.9%) in the placebo group. However the study was underpowered and the difference showed only a trend toward statistical significance (p < 0.135). This dilemma was resolved by the COPPS trial that was sufficiently powered to address this important question.
Conclusion:
Colchicine is safe and efficacious in the primary prevention of the PPS and its related complications and may halve the risk of developing the syndrome following cardiac surgery. Such a finding is particularly important for clinical practice because the post-operative management may be complex, troublesome and empirical anti-inflammatory therapy may not be efficacious. Primary prevention of postperiocardiotomy syndrome using short-term perioperative steroid treatment or intrapericardial steroid treatment or its combination with colchicine should be still further evaluated.