pHimpedanciometria para o diagnóstico da síndrome do refluxo: novas perspectivas


Marzio Frazzoni, Nicola de Bortoli, Leonardo Frazzoni, Salvatore Tolone, Vincenzo Savarino, Edoardo Savarino
Dig Dis Sci 2017; 62:1881–1889 Doi: 10.1007/s10620-017-4625-8

Neste trabalho os autores propõe um novo método de avaliação do exame de pHmetria com impedância para o diagnóstico de doença de refluxo gastroesofágico. A primeira é a Contração Peristáltica Pós-Refluxo Induzida por Deglutição (PSPW), que ocorre dentro de 30 segundos após o episódio de refluxo, e expressa por PSPW (%): número de refluxos seguidos por contração dentro de 30 segundos/ número total de refluxos. A outra variável é a Impedância Basal Noturna Média (MNBI), em Ohms, media da impedância basal em parte distal do esôfago medida em três períodos de 10 minutos, excluindo períodos de refluxo, deglutição e queda no pH, com o paciente deitado. O valores considerados como normais são > 61% para o PSPW e >2292 Ohms para o MNBI. Estas duas medidas tem alta sensibilidade e capacidade de diferenciar esofagite erosiva de doença não erosiva, e diferenciar estas duas da pirose funcional.

Impedance-pH monitoring for diagnosis of reflux disease: new perspectives
Marzio Frazzoni, Nicola de Bortoli, Leonardo Frazzoni, Salvatore Tolone, Vincenzo Savarino, Edoardo Savarino
Dig Dis Sci 2017; 62:1881–1889 doi: 10.1007/s10620-017-4625-8

Heartburn is the most specific symptom of gastroesophageal reflux disease (GERD). In clinical practice, heartburn relief by a proton pump inhibitor (PPI) trial does suffice to confirm GERD. However, an objective diagnosis of GERD is required before anti-reflux endoscopic or surgical
interventions, independently from PPI response. Thus, since normal findings at upper endoscopy are detected in the majority of patients with heartburn, reflux monitoring is often required. When traditional catheter-based or wireless pH tests are used, reflux episodes are conventionally identified
by pH drops below 4.0 units. Combined impedance-pH monitoring has the advantage to provide a comprehensive assessment of both physical and chemical properties of refluxate and the distinction between acid and weakly acidic refluxes, both proven to cause heartburn. Unfortunately, the conventional impedance-pH parameters, namely acid exposure time and number of reflux events, are characterized by suboptimal diagnostic sensitivity, and the reliability of symptom–reflux association indexes remains questionable. Therefore, novel impedance parameters, namely the postreflux swallow-induced peristaltic wave (PSPW) index and the mean nocturnal baseline impedance (MNBI), have recently been proposed in order to achieve a better diagnostic yield. In fact, they proved to be highly accurate in distinguishing reflux-related from reflux-unrelated heartburn, off- as well as on-PPI therapy. Currently, manual review of impedance-pH tracings is needed because of the modest accuracy of available software tools for automated analysis. PSPW index and MNBI are highly applicable and reproducible, and their calculation requires a few additional minutes during the manual review of impedance-pH tracings. So far, we believe that PSPW index and MNBI are ready for prime time and should become part of the standard analysis of impedance-pH tracings for GERD diagnosis in patients with endoscopy-negative heartburn.