Esophageal assessments of left ventricular filling pressures: A proof-of-concept study

OBJECTIVE: We sought to evaluate if left ventricular filling pressures can be assessed from the esophagus. BACKGROUND: The invasive assessment of left ventricular filling pressures is of importance in the evaluation and monitoring of critically ill patients. The left atrium is in very close proximity to the esophagus. We hypothesized that the temporal pressure decay characteristics of an esophageal fluid volume positioned at the level ofthe left atrium should depend on the atrial and left ventricular filling pressure. MATERIALS AND METHODS: In five pigs an esophageal balloon was placed at the level ofthe left atrium. The balloon was then pressurized to 50 mmHg followed by an automated release that allowed us to directly record the pressure decay, while simultaneously recording left atrial pressures. An algorithm was developed to estimate atrial pressures. We also tested if invasive transesophageal atrial pressures can be recorded via an ultrasound guided left atrial puncture. RESULTS: Noninvasive transesophageal assessments of left atrial pressures are feasible. The left atrial pressure directly affects the esophageal pressure decay and correlates with the transition point from an exponential pressure decay to a more linear decay (r = 0.949). This approach also allows for the assessment of atrial waveforms. We could also demonstrate that invasive transesophageal pressure measurements are feasible and safe. CONCLUSIONS: The esophagus allows for reproducible less invasive assessments of left ventricular filling pressures and atrial pressure waveforms. This close spatial relationship provides an alternative access site for diagnostic and therapeutic cardiac procedures.