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Biomedical subjects

Craig R Asher

Publications and source records attributed to Craig R Asher.

At least 19 recordsLinked to original sources
PubMed2005

Utility of transesophageal echocardiography in identification of thrombogenic milieu in patients with atrial fibrillation (an ACUTE ancillary study).

The ACUTE trial randomly assigned patients who had atrial fibrillation (AF) of >2 days' duration to a transesophageal echocardiographically guided or a conventional strategy before cardioversion. In the 571 patients who underwent transesophageal echocardiography (TEE) in the ACUTE trial, we assessed the relative predictive value of baseline data derived by history, transthoracic echocardiography, and TEE for prediction of thrombus and adjudicated embolism (thromboembolism) as a composite end point. TEE was performed at 70 centers in 571 patients, 549 in the transesophageal echocardiographically guided group and 22 crossovers in the conventional group. Six patients (1.1%) who had embolism and 79 (13.8%) who had thrombi were identified in this group. Thrombus was completely resolved in 76.5% of patients who had repeat transesophageal echocardiographic procedures after 31.7 +/- 7.5 days of anticoagulation. For patients who had embolic events, none had a transesophageal echocardiographically identified thrombus; 5 of 6 (83.3%) had >/=1 transesophageal echocardiographic risk factors (including spontaneous echocardiographic contrast, aortic atheroma, patent foramen ovale, atrial septal aneurysm, mitral valve strands), and 4 of 6 (66.66%) had subtherapeutic anticoagulation or no anticoagulation. Clinical, transthoracic echocardiographic, and transesophageal echocardiographic risk factors contributed significantly to the prediction of composite thrombus/embolism. However, transesophageal echocardiographic thromboembolic risk factors were the strongest predictors of thromboembolism and provided statistically significant incremental value (chi-square 38.0, p <0.001) for identification of risk. Thus, in addition to thrombus identification, TEE has significant incremental value in the identification of patients who had high thromboembolic risk. In conclusion, this study supports the role of TEE and anticoagulation monitoring in patients who have atrial fibrillation and is useful for identifying thromboembolic risk factors.

Aged↗
PubMed2005

Time to move to the right--the study of right ventricular systolic performance: too long neglected.

Although the evidence that right ventricular (RV) function has significant impact on cardiac hemodynamics and outcome is indisputable, its evaluation has been hampered by problems with image quality, geometric variability, and the absence of a standard of reference. A resurgence of research activity has sought to discern the pathophysiology of RV dysfunction and to explore new methods for measuring performance. Noninvasive techniques such as tissue Doppler echocardiography, three-dimensional echocardiography, and magnetic resonance imaging provide new quantitative information and may improve prediction of outcomes. These advances in technology, and the recognition that RV systolic function is essential in many conditions, provide the impetus for future studies. This review highlights the past and present efforts to incorporate RV systolic function into the mainstream of cardiology practice.

Diagnostic Imaging↗
PubMed2005

Non-invasive evaluation of orthotopic heart transplant rejection by echocardiography.

BACKGROUND: Heart transplant recipients require frequent myocardial biopsies to screen for acute rejection. The purpose of this study was to identify demographic and echocardiographic factors associated with transplant rejection and develop a predictive model, which may reduce the number of cardiac biopsies. METHODS: From January 1998 to December 2001, we performed 406 echocardiographic studies on 264 heart transplant patients who had biopsies performed on the same day. Two-dimensional, pulsed and tissue Doppler echocardiographic variables were compared between patients with and without rejection, and their predictive ability for detecting rejection was determined by uni- and multivariate analyses. RESULTS: In 268 biopsies there was no significant rejection (ISHLT Grade <==II), whereas 138 showed rejection (ISHLT Grade > or =IIIa). By multivariate analysis, pericardial effusion, isovolumic relaxation time (IVRT) <90 milliseconds and mitral inflow E/A ratio >1.7, diameter of inferior vena cava and duration of pulmonary vein atrial reversal were independently associated with rejection. Because the odds ratios were similar for all 5 predictors, a simplified model was developed based on the sum of the number of abnormal predictors present (0 to 5). The probability of rejection increased from 15.9%, in the absence of any predictor, to 39.7%, 52.0% and 71.1%, if 1, 2 or 3 predictors were present, respectively. CONCLUSIONS: Recipient age, pericardial effusion, IVRT and ratio of pulsed Doppler E/A are significant predictors of acute cardiac allograft rejection. However, no single predictor or combination of predictors were powerful enough to eliminate surveillance endomyocardial biopsies.

Adult↗
PubMed2005

A right atrial mass and a pseudomass.

Right atrial (RA) masses are rare entities often detected incidentally during imaging studies. Leading etiologies of right atrial masses are tumor, thrombi, and vegetations. We present two cases of right atrial masses, a cardiac lipoma and an artifact. Clinical and echocardiographic characteristics of benign cardiac tumors are reviewed. We then highlight the importance of considering artifact in the differential diagnosis of atrial masses. Finally, we discuss echocardiographic characteristics of right atrial masses that may provide clues for diagnosis. Right atrial masses, often detected incidentally during imaging studies, are uncommon and can be due to many etiologies including tumors, thrombus, vegetations, normal variants, and artifacts. We describe 2 patients with RA masses detected on routine transthoracic echocardiogram.

Aged↗
PubMed2004

Usefulness of real-time three-dimensional echocardiography for evaluation of myectomy in patients with hypertrophic cardiomyopathy.

Real-time 3-dimensional echocardiography was performed in 10 patients with obstructive hypertrophic cardiomyopathy (HC) before and after myectomy and in 6 controls. The exact location of systolic anterior motion of the mitral leaflet was shown in all patients with HC with a predominant involvement of the medial portion in 4 patients and the middle portion in 6 patients. The smallest area of the left ventricular outflow tract was significantly smaller in patients with HC than in controls (1.4 +/- 0.7 vs 5.1 +/- 1.2 cm(2), p <0.01), significantly increased after myectomy (4.8 +/- 1.8 cm2, p <0.01) and was associated with a reduction of the pressure gradient at rest from 63 +/- 41 to 15 +/- 5 mm Hg (p <0.01).

Adult↗
PubMed2004

Association of race with complications and prognosis following acute coronary syndromes.

The baseline characteristics, complications, and survival of 489 black and 6,890 non-black patients with acute coronary syndromes were studied. Important racial differences were observed in demographic features, atherosclerosis risk factors, and treatment strategies; however, despite these differences, no independent difference was observed in clinical outcomes according to race. The 1-year mortality rate was 2.9% for black patients and 2.5% for non-black patients (p = 0.93).

Acute Disease↗
PubMed2004

Pericarditis.

Pericarditis is a common disorder that has multiple causes and presents in various primary-care and secondary-care settings. New diagnostic techniques have improved the sampling and analysis of pericardial fluid and allow comprehensive characterisation of cause. Despite this advance, pericarditis is most commonly idiopathic, and radiation therapy, cardiac surgery, and percutaneous procedures have become important causes. Pericarditis is frequently self-limiting, and non-steroidal anti-inflammatory agents remain the first-line treatment for uncomplicated cases. Integrated use of new imaging methods facilitates accurate detection and management of complications such as pericardial effusion or constriction. Differentiation of constrictive pericarditis from restrictive cardiomyopathy remains a clinical challenge but is facilitated by tissue doppler and colour M-mode echocardiography. Most pericardial effusions can be safely managed with an echo-guided percutaneous approach. Pericardiectomy remains the definitive treatment for constrictive pericarditis and provides symptomatic relief in most cases. In the future, the pericardial space might become a conduit for treatments directed at the pericardium and myocardium.

Acute Disease↗
PubMed2004

Comparison of ability to identify left atrial thrombus by three-dimensional tomography versus transesophageal echocardiography in patients with atrial fibrillation.

We sought to determine the potential use of recently introduced cardiac 3-dimensional computed tomography as an alternative to transesophageal echocardiography for examination of the left atrial appendage. Our data suggest that computed tomography is a potential alternative for assessing the anatomy of the left atrial appendage and for detecting thrombi.

Atrial Fibrillation↗
PubMed2004

Conduction system abnormalities in patients with obstructive hypertrophic cardiomyopathy following septal reduction interventions.

We observed the impact of percutaneous transluminal septal myocardial ablation (PTSMA) and myectomy on the conduction system in patients with obstructive hypertrophic cardiomyopathy (HC). Septal reduction intervention is capable of eliminating the left ventricular outflow tract obstruction in patients with obstructive HC; however, conduction system abnormalities are frequent consequences of these procedures. A standard 12-lead electrocardiogram and Doppler echocardiogram were obtained in 204 patients who underwent PTSMA (n = 70) or myectomy (n = 134) before and at average of 3 months after intervention. Of 146 patients who had normal conduction systems before intervention, the duration of the QRS complex was significantly prolonged from 98 +/- 15 to 130 +/- 25 ms (p <0.0001), with right bundle branch block (RBBB) developing in 62% patients after PTSMA, and from 100 +/- 13 to 154 +/- 20 ms (p <0.0001), with left bundle branch block (LBBB) developing in 93% patients after myectomy. No significant difference in the QRS duration was found in the remaining 58 patients who had preexisting conduction abnormalities after intervention. In 174 patients without a preexisting permanent pacemaker, a pacemaker was implanted in 22% versus 13% of patients who underwent PTSMA (overall and without preexisting conduction block, respectively) and 10% versus 2% of patients with myectomy. The duration of baseline QRS was an independent predictor for the requirement of a permanent pacemaker (p <0.0001). Thus, RBBB often develops after PTSMA and LBBB is very frequently produced by myectomy. A possible requirement of a permanent pacemaker should always be considered before intervention when patients have preexisting RBBB or LBBB.

Bundle-Branch Block↗
PubMed2004

Noninvasive quantification of regional myocardial function using Doppler-derived velocity, displacement, strain rate, and strain in healthy volunteers: effects of aging.

Quantification of regional function can be performed using Doppler tissue echocardiography to evaluate myocardial velocity, tissue displacement, strain, and strain rate. Although these techniques have been validated in animal experiments and early clinical trials, there are only limited measurements in healthy populations to use as reference data. In 100 healthy volunteers, left ventricular myocardial velocity, displacement, strain, and strain rate were measured using Doppler tissue echocardiography. Measurements were obtained from basal, mid, and apical segments of walls visualized from left ventricular apical 4- and 2-chamber views. Analysis of covariance was used to examine the effects of age and wall segment position. All parameters showed a strong dependence on wall segment position. Although myocardial velocities and strain rate showed significant dependence on age, displacement and peak systolic strain measures were less affected. Like pulsed Doppler mitral inflow velocity, tissue velocity and strain rate show age-related changes.

Adolescent↗
PubMed2004

Evaluation of ventricular synchrony using novel Doppler echocardiographic indices in patients with heart failure receiving cardiac resynchronization therapy.

Cardiac resynchronization therapy improves hemodynamics in selected patients with heart failure. Mechanic asynchrony parameters that may guide patient selection or therapy optimization are still being investigated. A biventricular (BiV) pacemaker was implanted in 34 patients with dilated ischemic, idiopathic, or valvular cardiomyopathy, and a QRS duration of > or =130 milliseconds. Two-dimensional standard and Doppler tissue echocardiography was performed during right ventricular (RV), left ventricular (LV), BiV, and no pacing in a random and blinded manner. LV and BiV pacing increased stroke volume (P <.02 for both) and ejection fraction (P <.001 for both). Regional contractility assessed by displacement, strain rate, and peak systolic strain was improved in some segments (P <.05) during LV and BiV pacing. A homogenization of segmental contractions was observed during LV and BiV pacing as evaluated by net systolic displacement and segmental myocardial performance index. LV and BiV pacing provides benefits that can be quantified by echocardiography.

Analysis of Variance↗
PubMed2003

Importance of mitral valve repair associated with left ventricular reconstruction for patients with ischemic cardiomyopathy: a real-time three-dimensional echocardiographic study.

BACKGROUND: Left ventricular (LV) reconstruction surgery leads to early improvement in LV function in ischemic cardiomyopathy (ICM) patients. This study was designed to evaluate the impact of mitral valve (MV) repair associated with LV reconstruction on LV function 1-year after surgery in ICM patients assessed by real-time 3-dimensional echocardiography (3DE). METHODS AND RESULTS: Sixty ICM patients who underwent the combination surgery (LV reconstruction in 60, MV repair in 30, and revascularization in 52 patients) were studied. Real-time 3DE was performed and LV volumes were obtained at baseline, discharge, 6-month and >or=12-month follow-up. Reduction in end-diastolic volumes (EDV) by 29% and in end-systolic volumes by 38% were demonstrated immediately after surgery and remained at subsequent follow-up (P<0.0001). The LV ejection fraction significantly increased by about 10% at discharge and was maintained >or=12-month (P<0.0001). Although the LV volumes were significantly larger in patients with MV repair before surgery (EDV, 235+/-87 mL versus 193+/-67 mL, P<0.05), they were similar to LV volumes of the patients without MV repair at subsequent follow-ups. However, the EDV increased from 139+/-24 mL to 227+/-79 mL (P<0.01) in 7 patients with recurrent mitral regurgitation (MR). Improvement in New York Heart Association functional class occurred in 81% patients during late follow-up. CONCLUSIONS: Real-time 3DE demonstrates that LV reconstruction provides significant reduction in LV volumes and improvement in LV function which is sustained throughout the 1-year follow-up with 84% cardiac event free survival. If successful, MV repair may prevent LV redilation, while recurrent MR is associated with increased LV volumes.

Echocardiography, Three-Dimensional↗
PubMed2003

Transesophageal echocardiography to guide cardioversion in patients with atrial fibrillation: ACUTE trial update.

The Assessment of Cardioversion Using Transesophageal Echocardiography (ACUTE) trial was the first randomized prospective study to compare the conventional strategy of 3 weeks of anticoagulation before direct current cardioversion (DCC) for atrial fibrillation (AF) to a transesophageal echocardiography (TEE) guided approach with an expedited course of anticoagulation. This was a multicenter, international study with 70 sites enrolling 1222 patients between 1994-1999. The primary endpoint of composite embolic events and secondary endpoints including bleeding, functional status, prevalence of sinus rhythm, and death were assessed at 8 weeks following randomization. The ACUTE trial demonstrated that the TEE guided approach was safe and effective. There was no difference in the primary outcome of embolic events for the 2 strategies (0.8% TEE group vs. 0.5% conventional group, p =.50). There was a difference between the groups with respect to the number of bleeding events, with minor and major bleeding seen in 2.9% of patients in the TEE guided group and 5.5% in the conventional group (relative risk 0.53, 95% confidence interval 0.30-0.93, p = 0.03). The remaining secondary endpoints did not differ. Clinicians now have a viable alternative approach to cardioversion for patients with AF. Several factors influence the choice of strategies including (1) severity of symptoms and hemodynamic effect; (2) level and chronicity of anticoagulation; (3) risks of bleeding; (4) duration of AF and likelihood of reversion; and (5) risk and likelihood of left atrial thrombi. Future studies, such as ACUTE II are ongoing, with the aim of using low molecular weight heparin to further streamline the TEE guided approach to DCC and shorten hospital stay and costs.

Anticoagulants↗
PubMed2003

Transesophageal echocardiography in patients with atrial fibrillation.

Over the past decade transesophageal echocardiography (TEE) has become an integral tool in the management of patients with AF. Thrombi can be readily detected and the function of the left atrium and left atrial appendage (LAA) can be easily assessed by this modality. With this knowledge, informed decisions regarding anticoagulation, cardioversion, and the likelihood of restoring and maintaining sinus rhythm can be made. An alternative TEE-guided strategy for achieving sinus rhythm in patients with AF is now available with efficacy and safety similar to the conventional approach. Refinements of this strategy may include the use of low molecular weight heparin to avoid hospitalization in patients planned for cardioversion. Further uses of TEE in patients with AF are in their early stages including evaluation of patients following pulmonary vein radiofrequency ablation and those undergoing percutaneous or surgical closure of the LAA.

Atrial Fibrillation↗
PubMed2002

Survival after aortic valve replacement for severe aortic stenosis with low transvalvular gradients and severe left ventricular dysfunction.

OBJECTIVE: We sought to assess whether aortic valve replacement (AVR) among patients with severe aortic stenosis (AS), severe left ventricular (LV) dysfunction and a low transvalvular gradient (TVG) is associated with improved survival. BACKGROUND: The optimal management of patients with severe AS with severe LV dysfunction and a low TVG remains controversial. METHODS: Between 1990 and 1998, we evaluated 68 patients who underwent AVR at our institution (AVR group) and 89 patients who did not undergo AVR (control group), with an aortic valve area < or = 0.75 cm(2), LV ejection fraction < or = 35% and mean gradient < or = 30 mm Hg. Using propensity analysis, survival was compared between a cohort of 39 patients in the AVR group and 56 patients in the control group. RESULTS: Despite well-matched baseline characteristics among propensity-matched patients, the one- and four-year survival rates were markedly improved in patients in the AVR group (82% and 78%), as compared with patients in the control group (41% and 15%; p < 0.0001). By multivariable analysis, the main predictor of improved survival was AVR (adjusted risk ratio 0.19, 95% confidence interval 0.09 to 0.39; p < 0.0001). The only other predictors of mortality were age and the serum creatinine level. CONCLUSIONS: Among select patients with severe AS, severe LV dysfunction and a low TVG, AVR was associated with significantly improved survival.

Adult↗