John F. Sedgwick

The Role of Echocardiography in the Management of Patients Supported by Extracorporeal Membrane Oxygenation

Extracorporeal life support can be viewed as a spectrum of modalities based on modifications of a cardiopulmonary bypass circuit to provide cardiac and respiratory support, which can be used for extended periods, from hours to several weeks. Extracorporeal membrane oxygenation (ECMO) is among the most frequently used forms of extracorporeal life support. It can be configured for venovenous blood flow, to provide adequate oxygenation and carbon dioxide removal in isolated refractory respiratory failure, or in a venoarterial configuration, when support is required for cardiac and/or respiratory failure. Echocardiography plays a fundamental role throughout the entire journey of a patient supported on ECMO. It provides information that assists in patient selection, guides the insertion and placement of cannulas, monitors progress, detects complications, and helps in determining cardiac recovery and the weaning of ECMO support. Although there are extensive published data regarding ECMO, particularly in the pediatric population, there is a paucity of data outlining the role of echocardiography in guiding the management of adult patients supported by ECMO. ECMO is likely to become an increasingly used form of cardiorespiratory support within the critical care setting. Hence, clinicians and sonographers who work within echocardiography departments at institutions with ECMO programs require specific skills to image these patients.

Update on Echocardiography in the Management of Infective Endocarditis

Echocardiography is the major imaging modality used for the diagnosis of infective endocarditis (IE). It is also useful in detecting the complications of IE which often necessitate surgical intervention and strongly influence patient outcomes. Transesophageal echocardiography (TEE), with proven superiority over transthoracic echocardiography (TTE) for the detection of vegetations and complications such as abscess, should be performed in the vast majority of cases especially when TTE image quality is poor or implanted devices are present. Three-dimensional (3D) TEE provides enhanced display of anatomic-spatial relationships allowing more precise delineation of complex pathology, particularly of the mitral valve and annulus. Importantly, echocardiographic findings can be non-specific and should always be interpreted in the context of the pre-test probability of IE based on careful clinical assessment. IE remains a challenging disease associated with variable clinical presentations, and high mortality. Whenever IE is suspected, echocardiography should be utilized early for both diagnosis and detection of complications.

Tri-leaflet mitral valve variant of hypertrophic obstructive cardiomyopathy: Comprehensive assessment with 3-D transesophageal echocardiography

We report 2 cases of tri-leaflet mitral valve incidentally identified with perioperative transesophageal echocardiography (TEE) during surgical septal myectomy. 3-D TEE in both cases was crucial in confirming the diagnosis. A tri-leaflet mitral valve is an extremely rare finding. It has been associated with other congenital anomalies of the heart and is usually related to an anterior mitral leaflet cleft [1]. To our knowledge, this is the third case report in the literature [2,3] imaged with 3-D TEE illustrating three leaflets, with a distinct division arising at the region of the posterior scallop (P2) in the setting of HOCM. The first case is a 63 year old male patient with HOCM presented with gradual worsening dyspnea on exertion over 10 years. There was history of exercise-related syncope. The transthoracic echocardiogram (TTE) revealed significant LVOT obstruction with gradient of 106 mm Hg at rest and 127 mm Hg on Valsalva manoeuvre. There was moderate mitral regurgitation (grade 2/4 MR) at rest. The pre-pump TEE showed a tricuspid mitral valve with distinct anterior, medial and lateral leaflets. There was also a small partial small cleft at the tip of A2 scallop region. This was appreciated on 3-D imaging as well as from a deep trans-gastric view (see Fig. 1: Videos 1 and 2). The LVOT gradient was 7 mm Hg post-myectomy. There was a reduction in mitral regurgitation post-resection with residual MR arising from the A2 cleft.

Contrast microsphere enhancement of the tricuspid regurgitant spectral Doppler signal - Is it still necessary with contemporary scanners?

Background Accurate evaluation of the tricuspid regurgitant (TR) spectral Doppler signal is important during transthoracic echocardiographic (TTE) evaluation for pulmonary hypertension (PHT). Contrast enhancement improves Doppler backscatter. However, its incremental benefit with contemporary scanners is less well established. The aim of this study was to assess whether the TR spectral Doppler signal using contemporary scanners was improved using a second generation contrast agent, Definity® (CE), compared to unenhanced TTE (UE). Methods Analysis of patients who underwent UE then CE TR interrogation was performed. TR signal was evaluated by an experienced reader and graded 1 (clear-high level of confidence of interpretation and complete spectral Doppler envelope), 2 (suboptimal with medium-low level of confidence of interpretation and incomplete envelope), 3 (poor-absent and no measurable spectral Doppler signal). Maximal TR velocity (TRV) was defined as peak velocity that could be clearly identified. An inexperienced sonographer read 30 randomly selected studies. Results 176 TTE were performed in 173 patients (mean age 57 ± 14.8 years). Wilcoxon signed rank test demonstrated significant improvement (p < 0.0001) in TR spectral Doppler signal quality with CE TTE. Mean score CE TTE vs. TTE = 2.32 ± 0.85 vs. 2.56 ± 0.75 respectively (p < 0.0001). Mean maximal TRV CE TTE vs. UE TTE = 2.61 ± 0.44 m/s vs. 2.54 ± 0.49 m/s respectively (p < 0.0001). The inexperienced reader had a greater improvement in scoring CE TTE signals vs. UE TTE (p < 0.0001). Conclusion In the era of contemporary scanners, CE improved the ability to detect and measure TRV, except in those with clear unenhanced TR spectral Doppler signals or greater than mild tricuspid regurgitation.

Advanced Echocardiography for the Diagnosis and Management of Infective Endocarditis

Echocardiography is fundamental for the management of infective endocarditis (IE) across all stages of the illness including diagnosis, surveillance during medical therapy, identification of prognostic markers, planning perioperative intervention, postoperative assessment, and follow-up after completion of definitive therapy. Modern era echocardiography (echo) offers outstanding temporal and spatial image resolution, providing the opportunity for early diagnosis of this life-threatening infection. Emerging imaging modalities, such as real-time three-dimensional (3D) echocardiography, offer a novel way of readily visualizing the extent of intracardiac infection and the relationship of pathology to adjacent cardiac structures, well before surgical intervention, without radiation exposure or significant risk to the patient. Echocardiography can have a positive impact on the management of every stage of this disease, with the opportunity to improve outcomes.

Infected patent foramen ovale (PFO)

A 59 years old man presented with a late anterior STEMI, some hours after severe chest pain. He proceeded to primary angioplasty and stenting his proximal LAD artery. An intra-aortic balloon pump inserted for cardiogenic shock at the time of primary angioplasty. Contrast enhanced transthoracic echocardiography using Definity showed extensive regional wall motion abnormalities and an estimated ejection fraction of 14 %. A PICC line was inserted for intravenous inotropic support. The patient however, became febrile during his hospitalization. Blood cultures were taken and subsequently grew a hospital acquired MSSA secondary to PICC line insertion. A Trans-esophageal echocardiography was performed that demonstrated extensive thickening of the inter-atrial septum at the level of the fossa ovalis with an associated filamentous strand and globular mass that was mobile in the right atrium (measuring 9 mm by 10 mm), (panels A, B, C, D, E and F). Features were consistent with complex infection of a patent foramen ovale with right atrial extension (video 1, 2, 3 and video 4). Thrombus was felt to be less likely in the context of bacteremia and recent PICC line insertion, with positioning deep in the right atrium adjacent to the PFO. The patient was felt to be too high surgical risk for surgical debridement of the infected mass.

Obstructive mechanical valve thrombosis: utility of 3D trans-oesophageal echocardiography

A 73-year-old man presented to a tertiary Cardiothoracic Hospital with NYHA Class III dyspnoea and orthopnoea on the background history of bileaflet mechanical mitral valve replacement 20 years ago following an episode of infective endocarditis. Neurosurgery, to evacuate a subdural hematoma, had occurred 4 months earlier with warfarin reversal. In the period following neurosurgery, INR levels had been …

3-D Transoesophageal echocardiography for guiding percutaneous stenting of pulmonary vein stenosis

A 45-year-old woman presented with increasing dyspnoea and right-sided pleuritic chest pain 3 months post-catheter ablation for paroxysmal atrial fibrillation. A CT scan suggested that the right inferior pulmonary vein was completely occluded at the ostium. Transoesophageal echocardiography assessment of the right inferior pulmonary vein (RIPV on Panels A and B ) identified a narrow turbulent colour flow jet confirming …

The Role of Transoesophageal and Serial Echocardiography with a Normal Transthoracic Study And Clinical Suspicion of Staphylococcus aureus Infective Endocarditis

Methods: Lead explant data was reviewed for cases of cardiac device infection (CDI) since 2002. Echocardiographic findings and blood cultures for each patient were analysed to identify cases of true CDRIE, to differentiate from isolated pocket-site infection. Results: 377patients underwent lead extraction (total of 684 leads) of which 142were for CDI, and of those, 41 cases of CDRIE. Overall, CDRIE constituted 29% of all cases of CDI. Location of device lead vegetations were: within the RA [29/35], RV [5/35], SVC [1/35]. Mean vegetation size: 14mm x 6mm. Lead vegetations were associated with concomitant valve involvement in nine cases [26%], most commonly tricuspid valve [8/9]. Isolated valve involvement was seen mostly on TV [4/6 patients] with left-sided involvement being less common [AV-1/6; MV 1/6]. Main causative organisms were Staphylococcus aureus [34%] and Staphylococcus epidermidis [20%] with culture negative [5%]. Seventeen of 35 patients underwent both TTE and TOE, of which six had CDRIE correctly diagnosed on TTE. Overall, the sensitivity of TTE for detection of lead vegetations (with or without valvular involvement) was 37%. Conclusion: TTE alone is suboptimal to exclude CDRIE due to the low sensitivity and TOE should be considered in all patients with negative TTE and clinical suspicion of lead or valvular infection. http://dx.doi.org/10.1016/j.hlc.2013.05.479

The Utility of Three-dimensional Transoesophageal Echocardiography in the Assessment of Prosthetic Para-valvular Regurgitation

meanMV gradient before exercise was 1.35± 0.05mmHg and increased to 4.00± 0.16mmHg post-stress (p< 0.001). This represented a 196% increase in the gradients. In the last 40 patients, the left ventricular outflow tract (LVOT) velocity profiles were also measured, as an indicator of increased cardiac output with exertion. The LVOT mean gradient increased from 2.3± 0.74mmHg to 4.1± 1.72mm Hg (p< 0.001). This was only a 78% increase in these gradients. Conclusion: This study provides a normal range for the effect of exercise on normal mitral valve gradients. Additionally, trans-mitral valve gradients increased substantially more than the LVOT stroke volume (i.e. cardiac output). These data suggest that the mitral valve apparatus acts as a sphincter with exercise, becoming relatively stenotic, out of proportion to increases in cardiac output.