Recurrent pericarditis: the importance of guideline-based treatment for reducing recurrences. A single centre experience.

.Introduction Acute pericarditis, while generally considered a benign disease, may relapse in a sizable proportion of cases. Although innovative therapies, such as anti-IL1 drugs, have emerged as promising treatment options, the criteria for selecting patients for these therapeutic strategies remain inadequately defined. Furthermore, the role of inappropriate first-line treatments in potentially increasing the likelihood of relapses is not well defined, highlighting the need for strict adherence to guideline-defined treatment protocols from the first presentation of the disease and a precise characterization of relapsing pericarditis cases to identify patients candidates to third-line therapies. Purpose The aims of the study are: 1) to describe the clinical features of a single-center pericarditis patients’ cohort, 2) to evaluate the appropriateness, efficacy, and side effects of pericarditis medical therapy, 3) to identify prognostic predictors for pericarditis relapse, with particular focus on the role of inappropriate first-line medical therapies in favoring recurrences. Methods This study included patients diagnosed with pericarditis (according to the 2015 ESC criteria) prospectively enrolled and followed-up at the Cardioimmunology clinic of the Azienda Ospedale Università di Padova between 1993 and 2023. Data were collected using the REDCap electronic spreadsheet, including demographic, clinical, ECG, imaging and biochemical features at diagnosis and follow-up. The appropriateness of medical treatments was evaluated based on 2015 ESC Guidelines. Results The study included 249 patients. Our study cohort consisted of 149 males (60%) with a median age at diagnosis of 48 years (IQR 29, 63). Idiopathic or presumed infectious pericarditis was most prevalent (79%). Pericarditis due to systemic immune-mediated diseases was rare (10%). C-reactive protein at diagnosis was overall abnormal (91%). Follow up duration was of 17 months (IQR=9, 34). Inappropriate initial treatment with NSAIDs and steroids tended to be associated with future recurrences (respectively p=0.067 and p=0.069). On multivariable analysis, several baseline prognostic factors for relapse were identified: abnormal troponin at diagnosis (OR = 1.041, p < 0.001), unceasing presentation (OR = 8.685, 95% p=0.003), recurrent presentation (OR = 12.220, p=0.004)), and younger age (OR = 1.041, p < 0.001). After first-line treatment optimization, of the 22% of patients who presented relapses, 55% were effectively treated, and third line therapies such as anti-IL1 inhibitors were reserved to only 45% of initially defined recurrent pericarditis cases. Conclusion An incorrect first line therapy of a first episode of pericarditis diagnosis may be linked with future recurrences. Elevated troponin levels, recurrent or unceasing presentation, and younger age at diagnosis are predictors of pericarditis relapses, which should be treated strictly following a guideline-based approach. Third line therapies such as anti-IL1 agents may be reserved to a minority of properly selected relapsing pericarditis cases.