Speckle- Tracking Echocardiography for the Staging of Diastolic Dysfunction: The Correlation Between Strain-Based Indices and the Severity of Left Ventricular Diastolic Dysfunction.

OBJECTIVES: Left ventricular diastolic function can be assessed by various methods. Tissue Doppler imaging is among the most commonly used techniques. However, this imaging is angle- dependent, affected by loading conditions, and susceptible to myocardial tethering. Speckle- tracking echocardiography also can measure strain-based indices to assess diastolic function, and it has fewer limitations than tissue Doppler imaging. Using speckle- tracking echocardiography, the authors evaluated the correlation between the stage of diastolic dysfunction and strain-based indices in patients undergoing cardiac surgery to determine whether strain-based indices can be used intraoperatively to identify the extent of left ventricular diastolic dysfunction. DESIGN: Retrospective clinical study. SETTING: Single university hospital. PARTICIPANTS: Fifty-eight patients undergoing cardiac surgery (December 2017 to December 2019). INTERVENTIONS: None. Measurement and Main Result: Preoperative echocardiographic reports and intraoperative echocardiographic images of the participants were studied. The correlation between the stage of left ventricular diastolic dysfunction and strain-based indices (including early diastolic peak longitudinal strain and tissue deceleration time) were evaluated. Early diastolic peak longitudinal strain rate significantly correlated with the stage of diastolic dysfunction (r = -0.7 and p < 0.0001). Tissue deceleration time significantly correlated with the stage of diastolic dysfunction in patients with diastolic abnormality (r = -0.4 and p = 0.02). When patients with normal diastolic function were included, this correlation was not significant (r= -0.25 and p = 0.05). CONCLUSIONS: Intraoperatively measured early diastolic peak longitudinal strain rate and tissue deceleration time correlated with the severity of diastolic dysfunction in patients undergoing cardiac surgery.

Intraoperative assessment of left-ventricular diastolic function by two-dimensional speckle tracking echocardiography: relationship between pulmonary capillary wedge pressure and peak longitudinal strain rate during isovolumetric relaxation in patients undergoing coronary artery bypass graft surgery.

OBJECTIVES: Two-dimensional speckle tracking echocardiography has advantages over tissue Doppler imaging during isovolumetric relaxation for predicting left-ventricular end-diastolic pressure in non-surgical patients. Considering the direct and indirect effects of general anesthesia on hemodynamics, we examined correlations between strain-based indices during isovolumetric relaxation and pulmonary capillary wedge pressure in anesthetized patients. Moreover, we determined applicable cut-off values for strain-based indices to predict pulmonary capillary wedge pressure ≥15 mmHg intraoperatively. DESIGN: Retrospective clinical study. SETTING: Single university hospital. PARTICIPANTS: Thirty adult patients with preserved ejection fraction undergoing coronary artery bypass grafting. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two-dimensional speckle tracking echocardiography was used to measure strain rate during isovolumetric relaxation (SRIVR) and to calculate the mitral early diastolic inflow (E) to SRIVR ratio (E/SRIVR). Tissue Doppler imaging was used to calculate the E to early diastolic velocity at the lateral mitral annulus ratio (lateral E/e'). SRIVR and E/SRIVR showed strong correlations with pulmonary capillary wedge pressure (r = 0.80 and 0.73, respectively; p < 0.001 and p < 0.001). Lateral E/e' correlated with pulmonary capillary wedge pressure (r = 0.42; p < 0.05). SRIVR predicted high pulmonary capillary wedge pressure better than lateral E/e' did (areas under the receiver operating characteristic curves, 0.94-vs. 0.47, respectively). SRIVR <0.2 s-1 had a sensitivity of 100% and a specificity of 81% for predicting pulmonary capillary wedge pressure ≥15 mmHg. CONCLUSIONS: SRIVR is superior to tissue Doppler indices for predicting pulmonary capillary wedge pressure intraoperatively in patients with coronary artery disease and preserved ejection fraction.

Intraoperative Assessment of Coronary Artery Stenosis by 2D Speckle-Tracking Echocardiography: The Correlation Between Peak Strain Rate During Early Diastole and the Severity of Coronary Artery Stenosis in Patients Undergoing Coronary Artery Bypass Grafting.

OBJECTIVES: The effects of inhalation anesthetics on cardiac function and the low correlation between transthoracic and transesophageal echocardiographic measurements may alter the ability of transesophageal echocardiography-derived strain rate during early diastole to detect coronary artery stenosis in anesthetized patients. The authors assessed the correlation between coronary artery stenosis and strain-based parameters during early diastole in heart failure patients with preserved ejection fraction undergoing coronary artery bypass grafting. DESIGN: Retrospective clinical study. SETTING: Single university hospital. PARTICIPANTS: Thirty-two adult patients with preserved ejection fraction undergoing coronary artery bypass grafting between December 2016 and December 2018. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Transesophageal echocardiography images and coronary artery angiographies of the participants were studied. The correlation between the severity of coronary artery stenosis and strain-based indices measured in the corresponding left ventricular segments were assessed. Receiver operating characteristic curve analysis of strain rate during early diastole was used to predict the presence of coronary artery stenosis ≥70%. Regarding the severity of coronary artery stenosis, it demonstrated a strong and inverse correlation with strain rate during early diastole (r = -0.71, p < 0.001), but showed no significant correlation with time to peak strain rate during early diastole (r = 0.19, p = 0.18). Strain rate during early diastole ≤1.5 s-1 had a sensitivity of 77% and a specificity of 87% for predicting coronary artery stenosis ≥70% (area under the curve, 0.88). CONCLUSIONS: Strain rate during early diastole significantly correlates with the severity of coronary artery stenosis in anesthetized patients suffering from heart failure with preserved ejection fraction.

Spinal neuromodulation as a novel surgical option for failed back surgery syndrome following rhBMP exuberant bony growth in instrumented lumbar fusion: A case report and literature review.

BACKGROUND: Bone morphogenic protein (BMP) for instrumented lumbar fusion was approved in 2002, and since then has led to an increasing incidence of BMP-related neuropathic pain. These patients are usually resistant to conventional medical therapy and frequently undergo multiple surgical revisions without any pain relief. CASE DESCRIPTION: A 58-year-old male was referred to the author's outpatient clinic after four lumbar surgeries did not provide satisfactory pain relief. During his 10 years of suffering from low back pain after an injury, the patient was resistant to conventional and interventional treatment options. He was experiencing severe back pain rated 10/10, as well as right lower extremity pain, numbness, tingling, and motor deficits. Outside spine specialists had performed revision surgeries for BMP-related exuberant bone formation at L5-S1, which included the removal of the ipsilateral hardware and debridement of intradiscal and intraforamina heterotrophic exuberant bony formation. The author implanted the patient with a permanent continuous spinal cord stimulator, after which he achieved complete pain relief (0/10) and restoration of motor, sensory, autonomic, and sphincter functions. CONCLUSION: This is the first reported case of restorative function with neuromodulation therapy in a BMP-induced postoperative complication, which is considered as a primarily inflammatory process, rather than nerve root compression due to exuberant bony formation. We hypothesize that neuromodulation may enhance blood flow and interfere with inflammatory processes, in addition to functioning by the accepted gate control theory mechanism. The neuromodulation therapy should be strongly considered as a therapeutic approach, even with confirmed BMP-induced postoperative radiculitis, rather than proposing multiple surgical revisions.

Vasculopathy, Ischemia, and the Lateral Lumbar Interbody Fusion Surgery: Report of Three Cases.

Multi-modal neurophysiologic monitoring consisting of triggered and spontaneous electromyography and transcranial motor-evoked potentials may detect and prevent both acute and slow developing mechanical and vascular nerve injuries in lateral lumbar interbody fusion (LLIF) surgery. In case report 1, a marked reduction in the transcranial motor-evoked potentials on the operative side alerted to a 28% decrease in mean arterial blood pressure in a 54-year-old woman during an L3-4, L4-5 LLIF. After hemodynamic stability was regained, transcranial motor-evoked potentials returned to baseline and the patient suffered no postoperative complications. In case report 2, a peroneal nerve train-of-four stimulation threshold of 95 mA portended the potential for a triggered electromyography false negative in a 70-year-old woman with type 2 diabetes, peripheral neuropathy, and body mass index of 30.7 kg/m undergoing an L3-4, L4-5 LLIF. Higher triggered electromyography threshold values were applied to this patient's relatively quiescent triggered electromyography and the patient suffered no postoperative complications. In case report 3, the loss of right quadriceps motor-evoked potentials detected a retractor related nerve injury in a 59-year-old man undergoing an L4-5 LLIF. The surgery was aborted, but the patient suffered persistent postoperative right leg paresthesia and weakness. These reports highlight the sensitivity of peripheral nerve elements to ischemia (particularly in the presence of vascular risk factors) during the LLIF procedure and the need for dynamic multi-modal intraoperative monitoring.