Intraoperative Polymerase Chain Reaction from Cardiac Valve Tissue Is Beneficial for Guiding Further Therapy in Patients with Infective Endocarditis

Abstract

Background: Infectious endocarditis (IE) remains a critical condition despite all the medical advances in recent decades. Reliable pathogen identification is indispensable for precise therapy. The aim of this study was to evaluate the diagnostic and therapeutic benefit of additional polymerase chain reaction (PCR) in comparison with microbiological culture alone based on intraoperative tissue sampling for patients operated on due to IE. Methods: A total of 224 patients diagnosed with acute or subacute IE were analyzed. Intraoperatively resected infectious tissue was analyzed using both PCR and microbiological culture. Subsequently, the results of the detection of bacteria obtained based on intraoperative measurements from tissue via culture and PCR were compared with preoperative blood culture results. Furthermore, we evaluated the therapeutic impact of the culture and/or PCR results obtained from cardiac tissue. Results: The 224 patients were 63 ± 17 years old, and 64 (29%) were female. In total, 149 (67%) suffered from aortic valve endocarditis, 45 (45%) had mitral valve endocarditis, and 39 (18%) were afflicted with double-valve endocarditis. Prosthetic valve endocarditis was present in 70 (31%) patients. Pathogens were detected in 70% of the cases analyzed via PCR using cardiac valve tissue and in 25% of those analyzed via a culture of cardiac valve tissue; this figure was only 64% for preoperative blood culture. Overall, a pathogen was identified in 197 patients (88%), leading to antibiotic therapy. Targeted antibiotic therapy, based on the PCR results, was carried out in 37 cases and was conducted based on a culture from cardiac valve tissue in three cases. Finally, in 12% of patients, the causative pathogen remained unclear. Conclusions: For patients suffering endocarditis, PCR analysis is indispensable and superior to preoperative blood culture and intraoperative culture in detecting bacteria. Based on PCR testing, antibiotic therapy can be individually adjusted. The high precision of pathogen identification may lead to a significant reduction in IE-associated morbidity and mortality.