Swaminathan Karthik

Three-Dimensional Echocardiographic Assessment of Changes in Mitral Valve Geometry After Valve Repair

BACKGROUND Application of annuloplasty rings during mitral valve (MV) repair has been shown to significantly change the mitral annular geometry. Until recently, a comprehensive two-dimensional echocardiographic evaluation of annular geometric changes was difficult owing to its nonplanar orientation. In this study, an analysis of the three-dimensional intraoperative transesophageal echocardiographic evaluation of the MV annulus is presented before and immediately after repair. METHODS We performed three-dimensional geometric analysis on 75 patients undergoing MV repair during coronary artery bypass graft surgery for mitral regurgitation or myxomatous mitral valve disease. Geometric analysis of the MV was performed before and immediately after valve repair with full rings and annuloplasty bands. The acquired three-dimensional volumetric data were analyzed in the operating room. Specific measurements included annular diameter, leaflet lengths, the nonplanarity angle, and the circularity index. Before and after repair data were compared. RESULTS Complete echocardiographic assessment of the MV was feasible in 69 of 75 patients (92%) within 2 to 3 minutes of acquisition. Placement of full rings resulted in an increase in the nonplanarity angle or a less saddle shape of the native mitral annulus (137 +/- 14 versus 146 +/- 14; p = 0.002. By contrast, the nonplanarity angle did not change significantly after placement of partial rings. CONCLUSIONS Mitral annular nonplanarity can be assessed in the operating room. Application of full annuloplasty rings resulted in the mitral annulus becoming more planar. Partial annuloplasty bands did not significantly change the nonplanarity angle. Neither of the two types of rings restored the native annular planarity.

Transesophageal Echocardiography Simulator: A New Learning Tool

RANSESOPHAGEAL ECHOCARDIOGRAPHY (TEE)is a minimally invasive monitoring modality. The initialuse of TEE was limited to the acquisition of images in patientswith suboptimal echo windows during transthoracic echocar-diography. Its role has exponentially expanded to become al-most a standard of care during cardiac surgery and a valuableprocedural adjunct.

Intraoperative Application of Geometric Three-Dimensional Mitral Valve Assessment Package: A Feasibility Study

OBJECTIVE To study the feasibility of using 3-dimensional (3D) echocardiography in the operating room for mitral valve repair or replacement surgery. To perform geometric analysis of the mitral valve before and after repair. DESIGN Prospective observational study. SETTING Academic, tertiary care hospital. PARTICIPANTS Consecutive patients scheduled for mitral valve surgery. INTERVENTIONS Intraoperative reconstruction of 3D images of the mitral valve. RESULTS One hundred and two patients had 3D analysis of their mitral valve. Successful image reconstruction was performed in 93 patients-8 patients had arrhythmias or a dilated mitral valve annulus resulting in significant artifacts. Time from acquisition to reconstruction and analysis was less than 5 minutes. Surgeon identification of mitral valve anatomy was 100% accurate. CONCLUSIONS The study confirms the feasibility of performing intraoperative 3D reconstruction of the mitral valve. This data can be used for confirmation and communication of 2-dimensional data to the surgeons by obtaining a surgical view of the mitral valve. The incorporation of color-flow Doppler into these 3D images helps in identification of the commissural or perivalvular location of regurgitant orifice. With improvements in the processing power of the current generation of echocardiography equipment, it is possible to quickly acquire, reconstruct, and manipulate images to help with timely diagnosis and surgical planning.

CRITICAL CARE ISSUES FOR THE NEPHROLOGIST: Low‐dose Dopamine in the Intensive Care Unit

For much of the last four decades, low‐dose dopamine has been considered the drug of choice to treat and prevent renal failure in the intensive care unit (ICU). The multifactorial etiology of renal failure in the ICU and the presence of coexisting multisystem organ dysfunction make the design and execution of clinical trials to study this problem difficult. However, in the last decade, several meta‐analyses and one large randomized trial have all shown a lack of benefit of low‐dose dopamine in improving renal function. There are multiple reasons for this lack of efficacy. While dopamine does cause a diuretic effect, it does very little to improve mortality, creatinine clearance, or the incidence of dialysis. Evidence is also growing of its adverse effects on the immune, endocrine, and respiratory systems. It may also potentially increase mortality in sepsis. It is the opinion of the authors that the practice of using low‐dose dopamine should be abandoned. Other drugs and treatment modalities need to be explored to address the serious issue of renal failure in the ICU.

Real-time Three-dimensional Echocardiography for Left Atrial Appendage Ligation

A 77-yr-old woman was scheduled to undergo left atrial appendage (LAA) excision and bilateral pulmonary vein isolation through successive right and left mini-thoracotomy incisions for chronic atrial fibrillation. We used a conventional two-dimensional (2D) imaging probe/system (IE-33 Philips Medical Systems, Andover, MA) for a comprehensive transesophageal echocardiographic (TEE) examination and LAA interrogation. Starting from the midesophageal fourchamber plane, the LAA was visualized at 5° increments from 0° to 180° and the presence of spontaneous echo contrast or thrombus was excluded. LAA ejection velocity using pulse wave Doppler in the midesophagus at 0° and 90° rotation was 20 cm/s. Initially, the right-sided pulmonary veins were isolated through a right mini-thoracotomy incision. A left mini-thoracotomy was then performed and LAA excision was performed with a stapling device after left pulmonary venous isolation. Post-LAA excision 2D examination demonstrated a possible “incomplete” excision of the base of the LAA, which appeared as a residual “stump/pouch” of the LAA (Fig. 1) (Video 1; please see video clips available at www.anesthesia-analgesia.org). Because of limited TEE windows secondary to right lateral decubitus position and the small size of the pouch, definite flow could not be demonstrated using color flow Doppler (CFD) despite decreasing the Nyquist limit to 25 cm/s. To confirm our diagnosis of incomplete excision, we decided to use the real-time threedimensional (RT3D) TEE imaging probe on the same system for LAA visualization. Specifically, we used the “3D zoom” mode, which enables live 3D imaging of the intracardiac structures. An en-face view of the staple suture line from within the left atrium (LA) was obtained (Video 1). We were able to appreciate a small residual pouch. This residual LAA was then reexcised with simultaneous visualization with the “live” RT3D system. Positioning and placement of the stapling device was adjusted with simultaneous observation of disappearance of the pouch on the RT3D image. We then observed in “real-time” the application of the staples on the residual defect and its disappearance. Complete excision of the residual stump was also confirmed as absence of the previously visualized defect at the base of the LAA on 2D image as well (Video 1).

Intraoperative Assessment of Perivalvular Mitral Regurgitation: Utility of Three-Dimensional Echocardiography

A M E m c HE APPLICATION OF transesophageal echocardiography (TEE) for the assessment of prosthetic valve function is onsidered a category II indication.1 Although direct surgical xamination of the prosthetic mitral valve is considered the gold standard,” TEE provides a “dynamic” assessment of the alve under varying loading conditions.2 Three-dimensional 3D) TEE imaging may provide additional information to imrove the description of prosthetic valve function and the ocation of perivalvular leaks. The incorporation of color-flow oppler information in the 3D image may also help visualize he complex and eccentric mitral regurgitation (MR) jets. The vailability of this vital information in a timely fashion can help mprove the quality of intraoperative valve assessment. Conventional 2-dimensional (2D) transesophageal echocariography (TEE) is widely used intraoperatively in mitral valve urgery during both valve repair and valve replacement proceures.3 The identification of prosthetic mitral valve dysfunction n the immediate post–cardiopulmonary bypass (CPB) period an provide useful information as to the need for immediate orrective surgery. Previous application of 3D TEE for the ssessment of prosthetic valves in the immediate post-CPB eriod was hampered by the time necessary to acquire and econstruct the 3D volume sets. With the advent of faster econstructive software and hardware, intraoperative 3D echoardiography may provide additional information and improve patial orientation and communication regarding prosthetic alve regurgitation.4 This case report describes a clinical sceario in which the use of 3D echocardiographic reconstruction nd analysis during the post-CPB assessment facilitated idenification and location of a perivalvular leak misidentified with D imaging.

3D TEE and systolic anterior motion in hypertrophic cardiomyopathy.

Real-time 3-dimensional echocardiography allows for better visualization and understanding of morphology-to-function correlation among 3-dimensional cardiac phenomena than was possible with 2-dimensional echocardiography in the past (Online [Videos 1][1] and [2][2]) ([1][3]) ([Fig. 1][4]). One such

Myocardial Performance Index Is a Predictor of Outcome After Abdominal Aortic Aneurysm Repair

OBJECTIVE Perioperative measurement of the myocardial performance index (MPI) with transesophageal echocardiography in patients undergoing elective abdominal aortic aneurysm repair and its association with outcome. DESIGN A prospective observational study. SETTING A tertiary care university hospital. PARTICIPANTS Patients undergoing elective abdominal aortic aneurysm repair. INTERVENTION Perioperative transesophageal echocardiography. MEASUREMENTS Fifty-one consecutive patients undergoing elective abdominal aortic aneurysm repair were enrolled in the study. The MPI was calculated by using pulse-wave Doppler from the midesophageal window and the deep transgastric position of the probe. In addition, diastolic function was measured as the slope of the transmitral flow propagation velocity, and ejection fraction was calculated as a measure of ventricular systolic function. Comparisons between subjects with uncomplicated versus adverse outcomes were made by using a Mann-Whitney U test. Comparison of the incidence of adverse outcome among subjects with normal and elevated MPIs was made by using a Fisher exact test. Statistical significance was set at p < 0.05. RESULTS It was possible to calculate MPI in all patients with transesophageal echocardiography perioperatively. Patients with adverse postoperative outcomes had an elevated MPI as compared with those without any adverse outcome (0.50 v 0.30, p < 0.001). Also, an MPI of > or = 0.36 was associated with a statistically significant higher incidence of complications (congestive heart failure/prolonged intubation) (p < 0.001). CONCLUSIONS The MPI is an easily obtained echocardiographic measure of global ventricular performance, which can be measured perioperatively and may be useful as a prospective risk stratification index for patients undergoing elective abdominal aortic aneurysm surgery.

Current status of dynamic parameters of fluid loading.

Perioperative fluid management plays a critical role in the outcomes of surgical patients. There is an ongoing controversy between advocates of a liberal fluid management regimen and a more restrictive fluid replacement strategy. Traditional fluid management emphasizes the replacement of fluid deficits from fasting, insensible, and evaporative losses as well as estimating maintenance fluid and blood loss. Such calculations are thought to overestimate fluid requirements and lead to interstitial fluid accumulation and weight gain. Another approach uses the measurement of central venous pressures and pulmonary artery diastolic or wedge pressures as measures of cardiac preload. But these parameters have been shown to be completely unrelated to cardiac preload both in healthy volunteers as well as the critically ill. Recently a more restrictive fluid management regimen has been proposed, which involves replacing only definite fluid losses. This fluid strategy was shown to improve outcomes in certain critically ill surgical populations. Brandstrup et al demonstrated in a randomized trial that postoperative complications were fewer in the fluid restricted group of patients undergoing colon surgery. McArdle et al showed that positive fluid balance is predictive of major adverse events and increased high

Demonstration of Unilateral Absence of the Palmar Arch Without Collateral Circulation

A 27-year-old surgical resident from South America noticed occasional tingling in her right hand on awakening. She performed a modified Allen test1 on her own hands and noticed a subtle line of demarcation on the palm of her right hand accompanied by induction of similar tingling sensations. The demarcation was not seen on the left hand. We suspected an incomplete palmar arch, and to better demonstrate these findings, we wrapped the patient’s right hand with a latex bandage to exsanguinate the extremity. …