Left ventricular outflow tract and mid-cavity obstruction may cause false-positive dobutamine stress echocardiograms

ECHOCARDIOGRAPHY IN THIRTY AMERICAN FLAMINGOS (PHOENICOPTERUS RUBER) AND A CASE OF SUSPECTED NEURALLY MEDIATED REFLEX SYNCOPE

Heart disease in birds contributes to premature death and is usually detected postmortem. Echocardiography is a sensitive and noninvasive diagnostic modality but reported standard values for many species of birds, including American flamingos (Phoenicopterus ruber), are unavailable. Echocardiography was opportunistically performed on 30 unsedated American flamingos during their annual routine health examination. Structural heart disease was not found in any of the examined birds. However, 18 birds showed varying degrees of dynamic intraventricular obstruction. Echocardiographic parameters are reported. Benign neurocardiogenic weakness or syncopal events during handling were suspected in three birds. Stress combined with an intraventricular obstruction is believed to have triggered a cascade of parasympathetic innervation and sympathetic inhibition, similar to neurally mediated reflex syncope in humans.

Clinical implications of inducible left ventricular outflow tract obstruction among patients undergoing liver transplant evaluation

Introduction

Patients with end stage liver disease (ESLD) have a hyperdynamic state due to decreased systemic vascular resistance and increased cardiac output. Preoperative evaluation with dobutamine stress echocardiography (DSE) is used to risk-stratify patients prior to liver transplant. We sought to identify the impact of inducible left ventricular outflow tract obstruction (LVOTO) on DSE on post-operative liver transplant outcomes.

Methods

Patients with ESLD who underwent liver transplant at Cleveland Clinic between January 2007 and August 2016 were identified. Pre-operative DSE data, and post-operative intensive care unit (ICU) data were extracted. Patients with inducible LVOTO were compared to those without LVOTO.

Results

Of the 515 patients identified who underwent DSE prior to liver transplant, 165 (30%) were female, and 95 (18%) had LVOTO. There were no major differences in baseline characteristics between the two groups. In the LVOTO group, rest gradients were 10.8 ± 3 mm Hg while peak gradients were 90 ± 48.2 mm Hg. No significant differences in ICU length of stay or duration of mechanical ventilation between both groups were noted. There were 21 deaths at 30 days. There were 2 (2.1%) deaths in the LVOTO group, versus 19 (4.5%) deaths in the non LVOTO group (p = 0.28). Higher Model for End Stage Liver Disease (MELD) scores predicted longer duration of mechanical ventilation and ICU length of stay.

Conclusion

Inducible LVOTO on DSE does not adversely affect the short-term outcomes post liver transplant. Presence of inducible LVOTO should not be the mere reason to deny liver transplant among patients with ESLD.

Early dynamic left intraventricular obstruction is associated with hypovolemia and high mortality in septic shock patients

Introduction

Based on previously published case reports demonstrating dynamic left intraventricular obstruction (IVO) triggered by hypovolemia or catecholamines, this study aimed to establish: (1) IVO occurrence in septic shock patients; (2) correlation between the intraventricular gradient and volume status and fluid responsiveness; and (3) mortality rate.

Method

We prospectively analyzed patients with septic shock admitted to a general ICU over a 28-month period who presented Doppler signs of IVO. Clinical characteristics and hemodynamic parameters as well as echocardiographic data regarding left ventricular function, size, and calculated mass, and left ventricular outflow Doppler pattern and velocity before and after fluid infusions were recorded.

Results

During the study period, 218 patients with septic shock were admitted to our ICU. IVO was observed in 47 (22 %) patients. Mortality rate at 28 days was found to be higher in patients with than in patients without IVO (55 % versus 33 %, p < 0.01). Small, hypercontractile left ventricles (end-diastolic left ventricular surface 4.7 ± 2.1 cm²/m² and ejection fraction 82 ± 12 %), and frequent pseudohypertrophy were found in these patients. A rise ≥12 % in stroke index was found in 87 % of patients with IVO, with a drop of 47 % in IVO after fluid infusion.

Conclusion

Left IVO is a frequent event in septic shock patients with an important correlation with fluid responsiveness. The mortality rate was found to be higher in these patients in comparison with patients without obstruction.