Transesophageal imaging of the mid to distal left pulmonary artery in congenital heart disease

Transesophageal Echocardiography in Tetralogy of Fallot

Transesophageal echocardiography (TEE) plays an important role in the anatomical, functional, and hemodynamic assessment of patients with congenital heart disease (CHD). This imaging approach has been applied to both children and adults with a wide range of cardiovascular malformations. Extensive clinical experience documents significant contributions, particularly in the perioperative setting. In fact, in the current medical era, many consider this technology to be an essential adjunct to surgical and anesthetic management in CHD. This review focuses on the applications of TEE in patients with tetralogy of Fallot (TOF), the most common form of cyanotic heart disease. Emphasis is given to the perioperative use of this imaging modality and benefits derived during the prebypass and postbypass periods. Limitations and pitfalls relevant to the TEE assessment in patients with this anomaly are also addressed.

Intraoperative Epiaortic Ultrasound Scanning Guides Operative Strategies and Identifies Patients at High Risk during Coronary Artery Bypass Grafting

Objective

Epiaortic ultrasound (EU) reliably reveals ascending aortic atherosclerosis (AAA), allowing strategies to minimize the risk of embolization or plaque disruption during coronary artery bypass grafting. Our objective was to delineate if EU-guided intervention improved outcomes.

Methods

Patients undergoing coronary artery bypass grafting (2004–2007) were categorized by EU grade (grade 1–2 [mild] vs. 3–5 [moderate/severe]) and the use of an aortic clamp. A propensity score estimated probability of clamp use was based on 45 risk factors. Multiple logistic regression models measured the association between outcomes—death, stroke, myocardial infarction, and major adverse cardiac and cerebrovascular events (MACCE)—and the primary variables (grade and clamp use), adjusted for propensity score.

Results

Grade was available in 4278 patients. Patients with grade 3 to 5 AAA had an increased risk of death (adjusted odds ratios (AOR) 3.11; P < 0.001), stroke (AOR 2.12; P < 0.001), and MACCE (AOR 2.58; P < 0.001). Aortic clamping (any clamp, all grades) led to a higher risk of stroke (AOR 2.77; P = 0.032). EU altered aortic manipulation in 530 patients (12.4%). In this group, patients with high grade aortas had similar rates of death, stroke or MACCE, when compared with patients with low-grade aortas.

Conclusions

EU alters surgical strategy. Patients with grade 3 to 5 AAA are at increased risk of death, stroke, and MACCE compared with patients with grade 1 to 2 AAA. Clamping the aorta (any grade) increases the risk for stroke. Aortic clamping should be avoided in patients with grade 3 to 5 AAA, but EU may minimize morbidity and mortality if a clamp must be used.

The influence of epiaortic ultrasonography on intraoperative surgical management in 6051 cardiac surgical patients

BACKGROUND

Intraoperative echocardiography has become a mainstay monitor of cardiac function and a popular diagnostic tool in patients undergoing cardiac procedures. Previous reports suggest that epiaortic ultrasonography (EU) is superior to transesophageal echocardiography and manual palpation in identifying ascending aortic atheroma. Its impact on surgical decision making has not been thoroughly investigated, however.

METHODS

We retrospectively analyzed the medical records of 6051 consecutive patients who underwent EU of their ascending aorta during cardiac operations between 1996 and 2006 to determine a potential impact on intraoperative surgical decision making. Aortic atheroma was graded according to standard classification. Neurologic complications were evaluated according to the Society of Thoracic Surgeon definition for stroke and transient ischemic attack (TIA).

RESULTS

The overall impact of EU on surgical decision making was 4.1% and included a change in the technique for inducing cardiac arrest in 1.8%, aortic atherectomy or replacement surgery in 0.8%, requirement for off-pump coronary artery bypass grafting (CABG) in 0.6%, avoidance of aortic cross-clamping and use of ventricular fibrillatory arrest in 0.5%, change in arterial cannulation site in 0.2%, or avoidance of aortic cannulation in 0.2%. The greatest affect of EU was observed in patients undergoing combined CABG with aortic/mitral valve procedures (6.7%). The smallest impact was seen in patients undergoing mitral valve operations (1.4%). Aortic atheroma was more frequent on the anterior aspect of the aorta (n = 171) in patients with a change in surgical plan than on the posterior aspect (n = 78). The overall stroke rate was lower in patients with intraoperative EU compared with all patients undergoing surgical procedures.

CONCLUSIONS

Epiaortic ultrasonography is a useful technique to detect ascending aortic atheroma, has a significant impact on surgical decision making in more than 4% of cardiac surgical patients, and might result in improved perioperative neurologic outcome.

Transesophageal echocardiography for detecting extrapulmonary thrombi during pulmonary embolectomy

BACKGROUND

Pulmonary embolectomy is an evolving surgical procedure for the treatment of severe pulmonary embolism. In addition to removing pulmonary thromboemboli, the achievement of optimal results also requires identification and extraction of intrathoracic, extrapulmonary thromboemboli from the right atrium, right ventricle, and the superior or inferior vena cava. Otherwise, these thromboemboli may become the source of recurrent pulmonary embolism. Intraoperative transesophageal echocardiography is frequently used during pulmonary embolectomy as a guide for the surgeon and a monitor of cardiac performance. However, its utility for detecting concurrent intrathoracic, extrapulmonary thromboemboli has not been thoroughly investigated.

METHODS

The study population included 50 consecutive patients undergoing emergent pulmonary embolectomy. Results from preoperative diagnostic studies including transthoracic echocardiography; ventilation/perfusion scan, pulmonary angiography, and computed tomography were reviewed, along with the intraoperative echocardiographic reports for the presence of intrathoracic extrapulmonary thromboemboli. In addition, the surgical operative notes were consulted to determine the impact of intraoperative transesophageal echocardiography on surgical decision making.

RESULTS

Extrapulmonary intrathoracic thromboemboli were identified preoperatively in 8 patients (16%). Intraoperatively, thromboemboli were identified in 5 additional patients by transesophageal echocardiography, adding to a total of 13 patients with extrapulmonary thrombi (26%). Intraoperative transesophageal echocardiography provided the sole source of evidence that directed surgical management in 10% (5 of 50) of all patients undergoing pulmonary emboletcomy.

CONCLUSIONS

Intraoperative transesophageal echocardiography identified intrathoracic, extrapulmonary thomboemboli in 26% of patients undergoing pulmonary embolectomy, resulting in an alteration of surgical management in 10% of patients. These findings support the critical role of intraoperative echocardiography during pulmonary embolectomy.

Utility of intraoperative transesophageal echocardiography for diagnosis of pulmonary embolism

Pulmonary embolism (PE) is associated with significant perioperative morbidity and mortality. Transesophageal echocardiography (TEE) may permit direct visualization of PE or secondary signs of pulmonary artery (PA) obstruction. However, its utility in diagnosing PE in the intraoperative setting has yet to be defined. Therefore, we performed intraoperative TEE examinations in 46 patients immediately before pulmonary embolectomy. TEE examinations were reviewed for signs of thromboemboli within the right, left, and main PA, and secondary signs of acute PA obstruction (right ventricular dysfunction, moderate-to-severe tricuspid regurgitation, leftward bowing of the interatrial septum). The definitive location of thromboemboli was determined from the surgical record. Echocardiographic evidence for the presence of PE was correctly demonstrated in 46% of all patients (n = 21 of 46). However, the sensitivity for direct visualization of thromboemboli at any specific location was only 26%. TEE was least sensitive for thromboemboli in the left PA (17%). TEE evidence of right ventricular dysfunction was observed in 96%, tricuspid regurgitation in 50%, and leftward interatrial septal bowing in 98% of examinations. Therefore, the use of intraoperative TEE to diagnose acute PE via direct visualization is limited. Indirect TEE evidence of PA obstruction may be helpful in supporting a diagnosis of PE.