On-line multiplane transesophageal echocardiography for balloon mitral commissurotomy

Initial experience of using intracardiac echocardiography (ICE) for guiding balloon mitral valvuloplasty (BMV)

BACKGROUND AND AIMS

BMV is an established treatment for rheumatic mitral valve stenosis. The procedure is historically guided by fluoroscopy, and the role of intracardiac echocardiogram (ICE) guidance is not well defined. We report our initial experience of using ICE to guide BMV procedures.

METHODS

During BMV procedure, ICE catheter was inserted into the right atrium from the right femoral vein, and the septal puncture was monitored by ICE, as well as positioning of the balloon in the mitral valve. Comparisons were made between ICE, transthoracic echocardiography (TTE), and catheterization derived hemodynamic measurements (cath).

RESULTS

Seventeen patients with mitral stenosis underwent the procedure. The mean age was 44.4 ± 21 years. The mean MV area increased from 0.9 ± 0.1 cm(2) to 1.7 ± 0.2 cm(2), P < 0.0001 and the mean gradient decreased from 12.6 ± 5.8 mmHg to 4.9 ± 1.8 mmHg, P < 0.001. Atrial septum puncture and guidance of the balloon into the MV apparatus were obtained in all patients under ICE guidance. Severe MR developed in one patient and was readily detected by ICE. ICE derived gradient measurements were comparable to those obtained by TTE, and cath.

CONCLUSION

ICE guidance of BMV is feasible, and useful in monitoring safe septal puncture, optimizing balloon positioning, and in detecting complications. The hemodynamic measurements obtained were comparable to those obtained by TTE, and cath.

Echocardiography-guided interventions

A major advantage of echocardiography over other advanced imaging modalities (magnetic resonance imaging, computed tomographic angiography) is that echocardiography is mobile and real time. Echocardiograms can be recorded at the bedside, in the cardiac catheterization laboratory, in the cardiovascular intensive care unit, in the emergency room-indeed, any place that can accommodate a wheeled cart. This tremendous advantage allows for the performance of imaging immediately before, during, and after various procedures involving interventions. The purpose of this report is to review the use of echocardiography to guide interventions. We provide information on the selection of patients for interventions, monitoring during the performance of interventions, and assessing the effects of interventions after their completion. In this document, we address the use of echocardiography in commonly performed procedures: transatrial septal catheterization, pericardiocentesis, myocardial biopsy, percutaneous transvenous balloon valvuloplasty, catheter closure of atrial septal defects (ASDs) and patent foramen ovale (PFO), alcohol septal ablation for hypertrophic cardiomyopathy, and cardiac electrophysiology. A concluding section addresses interventions that are presently investigational but are likely to enter the realm of practice in the very near future: complex mitral valve repairs, left atrial appendage (LAA) occlusion devices, 3-dimensional (3D) echocardiographic guidance, and percutaneous aortic valve replacement. The use of echocardiography to select and guide cardiac resynchronization therapy has recently been addressed in a separate document published by the American Society of Echocardiography and is not further discussed in this document. The use of imaging techniques to guide even well-established procedures enhances the efficiency and safety of these procedures.

Intra-cardiac echocardiography guided trans-septal puncture in patients with dilated left atrium undergoing percutaneous transvenous mitral commissurotomy

Percutaneous transvenous mitral commissurotomy (PTMC) is an effective treatment for mitral stenosis, but trans-septal puncture carries a certain risk of complications. There have been few reports on phase-array intra-cardiac echocardiography (ICE) guidance in trans-septal puncture for PTMC, especially in patients with dilated left atrium or distorted anatomy. Herein, we report our preliminary experience with ICE-guided trans-septal puncture in patients with dilated left atrium (>or=5.5 cm) who underwent PTMC. From June 2005 to March 2006, there were nine consecutive patients with symptomatic mitral stenosis and left atrium size larger than 5.5 cm who underwent trans-septal puncture for PTMC with the ICE guidance in this institution by a same operator. The procedural and catheterization results were analyzed. Using ICE guidance, the success rate for trans-septal puncture was 100% for all patients with dilated left atrium (>or=5.5 cm). The trans-septal procedures were free of major and minor complications and the patients were not exposed to contrast medium. Mitral valve area increased significantly from 1.0+/-0.2 cm(2) to 1.9+/-0.2 cm(2). Our preliminary result showed that ICE safely and effectively guided trans-septal puncture for PTMC in patients with dilated left atrium (>or=5.5 cm), thus eliminating contrast medium usage and avoiding unnecessary longer X-ray exposure.

Feasibility of simplifying balloon mitral valvuloplasty by obviating left-sided cardiac catheterization using on-line guidance with transesophageal echocardiography

STUDY OBJECTIVES

The purpose of this study was to evaluate the feasibility of simplifying balloon mitral valvuloplasty through the obviation of left-sided cardiac catheterization using on-line guidance with transesophageal echocardiography in patients with mitral stenosis.

SETTING

A tertiary care medical center

DESIGN

Patients who were eligible for balloon mitral valvuloplasty were enrolled into the study if they had no evidence of ischemic heart disease. Sixty-six patients (50 women and 16 men) met the criteria. Balloon mitral valvuloplasty was performed through right-sided cardiac catheterization using adjunctive on-line guidance with transesophageal echocardiography. Left-sided catheterization was obviated.

MEASUREMENT AND RESULTS

Balloon mitral valvuloplasty was smoothly performed in all patients. Successful dilatation (postprocedural mitral orifice area, > 1.5 cm(2); or increment in mitral orifice area, >or= 50%) was achieved in 50 patients (75.8%). The mean (+/- SD) mitral orifice area increased from 1.08 +/- 0.23 cm(2) to 1.68 +/- 0.39 cm(2) (p = 0.0000). There were no in-hospital deaths, no patients with cardiac tamponade, or complications necessitating an emergency cardiac operation. The mean fluoroscopy time was 7.6 +/- 3.9 min, and the total procedure time was 50.2 +/- 15.0 min.

CONCLUSION

It is feasible and safe to simplify balloon mitral valvuloplasty by obviating left-sided cardiac catheterization in selected patients with mitral stenosis using adjunctive on-line guidance with transesophageal echocardiography.

Intra-atrial thrombolytic therapy for dissolution of chronic left atrial thrombi in patients undergoing balloon mitral commissurotomy

The purpose of this study was to evaluate the solubility of left atrial thrombi to thrombolytics after failure of long-term anticoagulant therapy in patient with mitral stenosis. One hundred and eighty-one consecutive patients with mitral valve area < or = 1.5 cm(2) and without severe mitral regurgitation were screened with echocardiography; 30 were found to have left atrial thrombi. Follow-up echocardiography performed 7.4 +/- 5.6 months after warfarin therapy revealed that 8/30 of patients had complete dissolution and 3/30 had partial dissolution of the thrombi. Thirteen patients with residual isolated appendageal thrombi underwent balloon mitral commissurotomy and were randomized into four groups at the end of balloon mitral commissurotomy: group A, receiving intra-atrial infusion of heparin and tissue plasminogen activator (t-PA; n = 4); group B, heparin and streptokinase (n = 3); group C, heparin (n = 3); and group D, acting as control (n = 3). It was found that only two patients in the t-PA group had their thrombi either completely or partially dissolved within 48 hr. Thus, this study suggests that t-PA may have the potential of dissolving chronic left atrial thrombi.

Intraoperative multiplane transesophageal echocardiography for guiding direct myocardial gene transfer of vascular endothelial growth factor in patients with refractory angina pectoris

Gene transfer for therapeutic angiogenesis represents a novel treatment for patients with chronic angina refractory to standard medical therapy and not amenable to conventional revascularization. We sought to assess the role of intraoperative multiplane transesophageal echocardiography (MPTEE) in guiding injection of naked DNA encoding vascular endothelial growth factor (VEGF) into the left ventricular (LV) myocardium of patients with refractory angina. After exposing the LV myocardium via a limited lateral thoracotomy, each of 17 patients in this series received 4 separate injections of VEGF DNA into different myocardial sites. Initial injections in the first patient produced intracavitary microbubbles, indicating injection of DNA into the LV chamber. Subsequently, each injection was preceded by a test injection of agitated saline. The absence of microbubbles while visualizing the LV cavity during the test injection verified that the ensuing injection of DNA would not be inadvertently squandered in the LV chamber itself. Intracavitary LV microbubbles were observed by MPTEE in 13 of 64 (20.3%) saline test injections and in 8 of 16 (50.0%) patients in which saline test injection was used, leading to adjustments in needle position. MPTEE imaging detected a previously unknown large, apical left ventricular thrombus in one patient, thereby preventing inadvertent injection of VEGF DNA through the myocardium into the thrombus. Imaging during and after injection verified no deleterious impact on LV function. We conclude that MPTEE is a useful tool for ensuring that myocardial gene therapy performed by direct needle injection results in gene transfer to the LV myocardium.

Intraoperative Echocardiography for the Patient Undergoing Minimally Invasive Heart Surgery

Minimally invasive heart surgeries are commonly used to avoid large surgical incisions and facilitate early extubation and recovery after cardiac surgeries. Trans esophageal echocardiography (TEE) is especially valu able in minimally invasive cardiac surgery because the inherently limited access to the thorax and mediasti num impairs direct visualization of the heart. TEE influ ences the clinical decision making process in several ways. Changes to the anesthetic management include alteration in volume loading in the presence of diastolic dysfunction or left ventricular outflow tract obstruction, as well as augmenting coronary perfusion pressure and implementing coronary vasodilators for new regional wall motion abnormalities. Changes to the surgical plans include replacement or repair for regurgitant valves, placement of intra-aortic balloon pumps for persistent regional wall motion abnormalities, and changing the surgical approach in the presence of severe aortic disease. Currently, two approaches are commonly used in minimally invasive cardiac surgery. The first approach, port-access minimally invasive car diac surgery, continues to use cardiopulmonary bypass. This approach relies extensively on TEE to correctly place endovascular devices necessary for cardiopulmo nary bypass in addition to routine assessment of car diac function. The second approach, minimally invasive direct coronary artery bypass, involves performing the revascularization on a beating heart. Here, TEE is essen tial for assessment of ventricular function if ischemic preconditioning is used as a strategy for myocardial protection.