Physician-performed point-of-care echocardiography using a laptop platform compared with physical examination in the cardiovascular patient

Diagnostic accuracy and cost-effectiveness of a pocket-sized transthoracic echocardiographic imaging device

BACKGROUND

The recently introduced pocket-sized portable transthoracic echocardiography (pTTE) is accurate for measurement of cardiac chamber size and function as well as for assessment of valvular regurgitation. This study aimed to compare the diagnostic accuracy of the pocket-sized pTTE with the standard TTE (sTTE) and assess its cost-effectiveness.

HYPOTHESIS

The use of pocket-sized pTTE, as an initial screening tool, may be feasible, accurate and cost-effective in the diagnostic strategy of cardiac abnormalities.

METHODS

The study subjects were 200 patients scheduled for sTTE and an electrocardiogram (ECG). Each patient underwent pTTE examination with the Vscan (GE Medical Systems, Milwaukee, WI) immediately after sTTE. The findings of pTTE and the ECG were compared with the results of sTTE. Cost-effectiveness was calculated.

RESULTS

There was a strong agreement in the detection of abnormal findings between pTTE and sTTE (agreement = 90%), whereas the agreement between the ECG and sTTE was 65%. When pTTE or the ECG was used as an initial screening tool prior to sTTE, similar cost reduction was obtained (approximately 30%) by reducing the number of referrals for sTTE. However, the negative predictive value of a diagnostic strategy with pTTE (92%) was superior to that with an ECG (67%).

CONCLUSIONS

This study demonstrates that the pocket-sized pTTE provides accurate detection of cardiac structural and functional abnormalities beyond the ECG. In addition, the use of pTTE as an initial screening tool prior to sTTE is cost-effective, suggesting that the pocket-sized pTTE is poised to alter the current diagnostic strategy in clinical practice.

Advances in pediatric cardiac intensive care

Pediatric cardiac critical care has made, and continues to make, significant strides in improving outcomes. It is a measure of these successes that much of the discussion in this article does not focus on the reduction of mortality, but rather on perioperative management strategies intended to improve neurologic outcomes. The care of children with critical cardiac disease will continue to rely on broad and collaborative efforts by specialists and primary care practitioners to build on this foundation of success.

Pocket-size imaging device: effectiveness for ward-based transthoracic studies

AIMS

Pocket-size imaging devices (PSID) are now available; their potential role in a hospital environment has been investigated but still remains undefined.

METHODS AND RESULTS

We evaluated the effectiveness of PSID in 92 patients referred for bedside transthoracic echocardiogram (TTE). Patients were included where there was a focused clinical question: quantification of left ventricular function (LVF); presence of regional wall motion abnormalities (RWMA); evidence of pericardial effusion, exclusion of significant valve pathology. Each patient underwent an echocardiography evaluation using PSID and TTE. In 83 patients [k = 90%, 95% CI (82.2-95.4)], it was possible to answer the clinical question by PSID examination alone. There was agreement between the findings of PSID and TTE in 86 cases [79%; k = 47%, 95% CI (12.8-82.0)], in three cases, the clinical question was not answered by both modalities. When the clinical question was focused on LVF, the agreement was excellent [k = 96%, 95% CI (95.3-97.9)], as was the agreement in the detection of RWMA [k = 94.57%, 95% CI (82.4-95.1)]. There was also good concordance in the detection of valve pathology and pericardial effusion. Using PSID, the reduction in the scanning and reporting time was 66%. The cost-effectiveness analysis produced very favourable results: with PSE, we obtained an overall cost saving per scan of 76%, compared with TTE.

CONCLUSION

This study demonstrates that PSID can provide a valuable alternative to TTE in the presence of focused clinical questions and can provide an efficient way of delivering a ward-based transthoracic echo service.

Prevalence of asymptomatic left ventricular systolic dysfunction in at-risk medical inpatients

BACKGROUND

Asymptomatic left ventricular systolic dysfunction is an important risk factor for heart failure and death. Given the availability of patients, trained personnel, and equipment, the hospital is an ideal setting to identify and initiate treatment for left ventricular systolic dysfunction. The purpose of this study was to determine the prevalence of asymptomatic left ventricular systolic dysfunction in patients 45 years of age or older with at least one clinical heart failure risk factor admitted to a general medical service.

METHODS

Bedside, hand-carried echocardiography provided quantitative assessment of left ventricular systolic function in 217 medical inpatients 45 years of age or older who had at least one heart failure risk factor. Patients with known or suspected heart failure or with an assessment of left ventricular function in the past 5 years were excluded. We measured the prevalence of asymptomatic left ventricular systolic dysfunction, defined by left ventricular ejection fraction of 50% or lower, and its association with heart failure risk factors.

RESULTS

Of 207 patients with interpretable images, 11 (5.3%) had a left ventricular ejection fraction of 50% or lower. Patients with left ventricular systolic dysfunction had more heart failure risk factors than those without left ventricular systolic dysfunction (3.09±0.8 vs 2.5±1.0, P=.04). The total number of heart failure risk factors trended towards an association with a greater prevalence of asymptomatic left ventricular systolic dysfunction, but this did not reach significance (odds ratio 1.74; 95% confidence interval, 0.97-3.12, P=.06).

CONCLUSIONS

Asymptomatic left ventricular systolic dysfunction is present in about 1 of every 20 general medical inpatients with at least one risk factor for heart failure. Because treatment of asymptomatic left ventricular systolic dysfunction may reduce morbidity, further studies examining the costs and benefits of using hand-carried ultrasound to identify this important condition in general medical inpatients are warranted.

Review article: Clinical impact of non-cardiologist-performed transthoracic echocardiography in emergency medicine, intensive care medicine and anaesthesia

There is increased realisation of the emerging role of point-of-care transthoracic echocardiography (TTE) as 'ultrasound-assisted examination', given the low sensitivity of clinical examination for cardiovascular pathologies and the time-critical nature of these pathologies. There is evidence that point-of-care TTE provides higher accuracy in patient assessment and management, with potential prognostic impact by assessing the severity of cardiac dysfunction and response to treatment. Point-of-care TTE is increasingly used by non-cardiologists, as a diagnostic, screening or monitoring tool. The literature shows that TTE identifies new clinical findings, and conversely can accurately rule out clinically important pathologies. Recent reports have examined more advanced ultrasound devices and patients in the critical care settings of emergency medicine, intensive care and anaesthesia. The diagnostic capability of new portable devices is improving rapidly and outdating its predecessors, thereby improving confidence in echocardiography findings.

Diagnostic influence of cardiovascular screening by pocket-size ultrasound in a cardiac unit

AIMS

We aimed to study the diagnostic influence of adding a routine cardiovascular ultrasound screening of the cardiac anatomy and function, the pericardium, the pleura and the abdominal great vessels by the new pocket-size ultrasound device (pUS) with grey scale and colour Doppler imaging.

METHODS AND RESULTS

In 119 randomly selected patients admitted to a cardiac unit at a non-university hospital, routinely adding a cardiovascular ultrasonography of only 4.4 min with a pocket-size device corrected the primary diagnosis in 16% of patients. In addition, 29% had the primary diagnosis verified and in 10% an additional important diagnosis was made. Higher age predicted any diagnostic influence of pUS screening with an increase of 61% (P=0.003) per 10 years of higher age. Overall, the pUS screening had a sensitivity and specificity with respect to detecting at least moderate pathology of 97 and 93%. Positive and negative predictive values were 93 and 87%, respectively. In the sub-group of subjects with a change in the primary diagnosis following pUS there was no false-negative or false-positive findings.

CONCLUSION

Screening by pUS assessed vascular and cardiac anatomy and function accurately and enabled correction of the diagnosis in 16% of patients admitted to a cardiac unit. In 55% of the participants, the cardiovascular ultrasound screening had important diagnostic influence. We suggest that it would be appropriate to implement strategies and systems for routinely adding an ultrasound cardiovascular examination to patients in cardiac units.

The Dutch experience of open access echocardiography

Cardiac disease is not easy to recognise in general practice. An echocardiogram is an excellent way to provide information about left ventricular mass and diastolic (dys)function and the presence of valvular heart disease. To improve diagnostic care of cardiac patients, an open access echocardiography service was established in the referral area of our hospital, where general practitioners were able to ask for an echocardiogram without referring the patient to the cardiologist. Between December 2002 and October 2006 echocardiograms were requested for 471 patients. Thirteen percent of the patients referred for dyspnoea and 3% of patients with a cardiac murmur had a left ventricular ejection fraction <40%. In 28% of patients no cardiac abnormality could be found. If we looked at the prevalence of hypertension in the referred patients, this was very high with a prevalence of up to 60% in the older age groups. If we included hypertension in the analysis, only 16% of patients had no structural cardiac or vascular abnormality. The study shows that the advantage of open access echocardiography in the Netherlands is that the general practitioner is able to make a better diagnosis and unnecessary referrals of patients with suspected cardiac disease can be avoided. (Neth Heart J 2007;15:342-7.).

Validation of the smallest pocket echoscopic device's diagnostic capabilities in heart investigation

We hypothesized that, based on greyscale imaging and color Doppler capabilities, a new pocket ultrasound device (PUD) could accurately record cardiologic diagnostic findings. One hundred patients referred for conventional clinical indications underwent a standard echocardiography. Subsequently, a second physician blinded to the results performed an evaluation using the PUD on the same patients. Study end-points were echocardiographic window quality; left ventricular (LV) morphology; function; hypertrophy; right ventricular, atrial and vena caval morphologies; aortic and mitral valvulopathies; and pericardial structure. Using a scale of three grades, concordance in image quality proved good with a kappa coefficient (κ) of 0.71. Concordances between systems were excellent for LV function and morphology (κ = 0.91 and 0.96). Concordance for LV hypertrophy was good (κ = 0.74). Concordances for mitral regurgitation grades were 0.90, 0.95 and 1.00, respectively. In conclusion, a new PUD enabled scanning examinations, which showed good concordance of basic and qualitative diagnostic capability to standard echocardiographic instruments.

Hand-carried ultrasound devices in pediatric cardiology: clinical experience with three different devices in 110 patients

BACKGROUND

The aims of this study were to determine the usefulness of hand-carried ultrasound devices in pediatric cardiology and to compare the performance of three different hand-carried ultrasound devices in a pediatric cardiology outpatient clinic and intensive care unit.

METHODS

One hundred ten patients (49 male; mean age, 6.4 ± 5.2 years; range 0.1-38 years) with congenital heart defects or innocent heart murmurs were examined using Siemens Acuson P10, Siemens Acuson P50, and Philips CX 50 systems. The quality of images and the accuracy of B-mode measurements were compared with those obtained using a standard echocardiographic system (Philips iE33).

RESULTS

Fifty-nine patients were examined with the Siemens Acuson P10, 29 with the Siemens Acuson P50, and 22 with the Philips CX 50 system. There were no significant differences in B-mode measurements. The Acuson P10 system, however, showed significantly lower image quality, with 64.54% of all studies considered of excellent quality compared with 92.83% with the Acuson P50 and 95.52% with the CX 50 (P < .05) and a mean quality score (1 = fair, 5 = excellent) of 3.5 versus 4.57 with the Acuson P50 and 4.86 with the CX 50 (P < .05). This was attributed to the limited capacity for accurate diagnosis in children with body weights < 10 kg and complex heart defects.

CONCLUSION

Hand-carried ultrasound devices represent a valuable alternative to standard echocardiographic systems in pediatric cardiology. In particular, systems including all echocardiographic modalities offer unlimited versatility in outpatient and intensive care.

Improved cardiovascular diagnostic accuracy by pocket size imaging device in non-cardiologic outpatients: the NaUSiCa (Naples Ultrasound Stethoscope in Cardiology) study

Miniaturization has evolved in the creation of a pocket-size imaging device which can be utilized as an ultrasound stethoscope. This study assessed the additional diagnostic power of pocket size device by both experts operators and trainees in comparison with physical examination and its appropriateness of use in comparison with standard echo machine in a non-cardiologic population.

Three hundred four consecutive non cardiologic outpatients underwent a sequential assessment including physical examination, pocket size imaging device and standard Doppler-echo exam. Pocket size device was used by both expert operators and trainees (who received specific training before the beginning of the study). All the operators were requested to give only visual, qualitative insights on specific issues. All standard Doppler-echo exams were performed by expert operators.

One hundred two pocket size device exams were performed by experts and two hundred two by trainees. The time duration of the pocket size device exam was 304 ± 117 sec. Diagnosis of cardiac abnormalities was made in 38.2% of cases by physical examination and in 69.7% of cases by physical examination + pocket size device (additional diagnostic power = 31.5%, p < 0.0001). The overall K between pocket size device and standard Doppler-echo was 0.67 in the pooled population (0.84 by experts and 0.58 by trainees). K was suboptimal for trainees in the eyeball evaluation of ejection fraction, left atrial dilation and right ventricular dilation. Overall sensitivity was 91% and specificity 76%. Sensitivity and specificity were lower in trainees than in experts.

In conclusion, pocket size device showed a relevant additional diagnostic value in comparison with physical examination. Sensitivity and specificity were good in experts and suboptimal in trainees. Specificity was particularly influenced by the level of experience. Training programs are needed for pocket size device users.

Usefulness of a new miniaturized echocardiographic system in outpatient cardiology consultations as an extension of physical examination

BACKGROUND

The aim of this study was to assess the usefulness of a new miniaturized echocardiographic system (MS) to perform bedside echocardiography in initial outpatient cardiology consultations, in addition to physical examination.

METHODS

One hundred eighty-nine patients referred for initial cardiology outpatient consultations at two tertiary hospitals in two countries were studied. Each patient was submitted to physical examination followed by MS assessment. Scanning time, the number of examinations with abnormal results after physical examination and the MS, and the information obtained by physical examination alone and followed by the MS (in terms of its importance in reaching a diagnosis, in the necessity of performing routine echocardiography, and in the decision to release the patient from the outpatient clinic) were assessed.

RESULTS

The scanning time with the MS was 180 ± 86 seconds. Its use after physical examination led to diagnoses in 141 patients (74.6%) and to an additional 37 patients (19.6%) being released from the outpatient clinic. After physical examination followed by MS assessment, only 64 patients (33.9%) were sent to the echocardiography lab. The MS modified the decision of whether to send a patient to the echocardiography lab, with referral determined by the MS in 27 patients (14.3%) and no referral determined by the MS in 58 patients (30.7%).

CONCLUSIONS

The new MS caused a negligible increase in the duration of consultations. It showed additive clinical value over physical examination, increasing the number of diagnoses, reducing the use of unnecessary routine echocardiography, increasing the number of adequate echocardiographic studies, and determining a large number of releases from the outpatient clinic.

New pocket echocardiography device is interchangeable with high-end portable system when performed by experienced examiners

BACKGROUND

Cardiovascular status is a crucial determinant in the pre-operative assessment of patients for surgery as well as for the handling of patients with acute illness. We hypothesized that focus-assessed transthoracic echocardiography (FATE) could be performed with the subject in the semi-recumbent position. The aim was also to test whether the image quality of Vscan is interchangeable with a conventional high-quality portable echocardiography system. Furthermore, we evaluated the time needed to achieve an interpretable four-chamber view and to complete a full FATE examination.

METHODS

Sixty-one subjects were included. All subjects were examined in accordance with the FATE protocol in the semi-recumbent position on two different systems: the novel Vscan pocket device and the high-quality portable Vivid i system. Two evaluations were performed. In group A (n=30), the focus was on image quality. In group B (n=31), the focus was on the time consumed.

RESULTS

Group A: All patients (100%) had at least one image suitable for interpretation and no significant difference in image quality (P=0.32) was found between the two different systems. Group B: The mean value for the total time consumed for a full FATE was 69.3 s (59.8-78.8) on the Vscan and 63.7s (56.7-70.8) on the Vivid i, with no significant difference among the scanners (P=0.08).

CONCLUSION

The Vscan displays image quality interchangeable with larger and more expensive systems. The apparatus is well suited for performing a FATE examination in a 1-day surgery setting and could very well also be applicable in almost any situation involving patients with acute illness.

Hospitalist use of hand-carried ultrasound: preparing for battle

Hand-carried ultrasound (HCU) is a burgeoning technology at a critical point in its development as a general diagnostic technique. Despite the known safety and accuracy of ultrasound in radiology and echocardiography, the use of HCU to augment physical diagnosis by all physicians has yet unrealized potential. In order to incorporate ultrasound into a diagnostic model of routine bedside application, simple imaging and training protocols must first be derived and validated. Simplified cardiac ultrasound exams have already been validated to detect evidence-based targets such as subclinical atherosclerosis, heart failure, and elevated central venous pressures. However, for general examination of the acutely ill patient, it is the internist-hospitalist who should derive a full-body ultrasound examination, balancing training requirements with the numerous clinical applications potentially available. As the hospital's leading diagnostician with ultrasound expertise available in-house, the hospitalist could develop HCU so as to triage and refer more appropriately and limit unnecessary testing and hospital stays. Active involvement by hospitalists now in the planning of outcome, validation, and training studies, will be invaluable in the formation of an "ultrasound-assisted" physical examination in the future and will promote competent, cost-effective applications of HCU within general medical practice.

Hand-carried ultrasound performed by hospitalists: does it improve the cardiac physical examination?

OBJECTIVE

The traditional physical examination of the heart is relatively inaccurate. There is little information regarding whether cardiac hand-carried ultrasound performed by noncardiologists adds to the accuracy of physical examinations. The purpose of this study was to determine whether hand-carried ultrasound can add to the accuracy of hospitalists' cardiac physical examinations.

METHODS

During a focused training program in hand-carried echocardiography, 10 hospitalists performed cardiac examinations of 354 general medical inpatients first by physical examination and then by hand-carried ultrasound. Eligible inpatients included those for whom a conventional hospital echocardiogram was ordered. We measured how frequently the hospitalists' cardiac examination with or without hand-carried ultrasound matched or came within 1 scale level of an expert cardiologist's interpretation of the hospital echocardiogram.

RESULTS

Adding hand-carried ultrasound to the physical examination improved hospitalists' assessment of left ventricular function, cardiomegaly, and pericardial effusion. For left ventricular function, using hand-carried ultrasound increased the percentage of exact matches with the expert cardiologist's assessment from 46% to 59% (P=.005) and improved the percentage of within 1-level matches from 67% to 88% (P=.0001). The addition of hand-carried ultrasound failed to improve the assessments of aortic stenosis, aortic regurgitation, and mitral regurgitation.

CONCLUSION

Adding hand-carried ultrasound to physical examination increases the accuracy of hospitalists' assessment of left ventricular dysfunction, cardiomegaly, and pericardial effusion, and fails to improve assessment of valvular heart disease. The clinical benefit achieved by improved immediacy of this information has not been determined. An important limitation is that the study assessed only 1 level of training in hand-carried ultrasound.

The prevalence and clinical impact of pulmonary artery sling on school-aged children: a large-scale screening study

BACKGROUND

Airway obstruction is a leading cause of mortality and morbidity in patients with pulmonary artery sling (PAS). Early identification of PAS is imperative for prompt initiation of appropriate treatments.

OBJECTIVE

Our aim was to investigate the prevalence and clinical impact of PAS on school-aged children through a large-scale pre-sports participation cardiovascular screening (PPCVS) study.

METHODS

A total of 186,213 school-aged children underwent portable two-dimensional echocardiography (2DE) study in a PPCVS study between 2001 and 2004 in Taichung City, Taiwan. We prospectively collected data on the prevalence of PSA, demographics, clinical features, tracheo-bronchial anomalies (TBA), on computed tomography (CT), pulmonary function test (PFT), follow-up data in 1 year, and clinical outcomes.

RESULTS

PAS was identified in 11 children (8 males/3 females) with a median age of 13 years (range: 7.2-13.7 years). The prevalence of PAS was 1 in 17,000 school-aged children. The majority of children with PAS had recurrent broncho-pulmonary infections (90.9%) and asthmatic cough (81.8%), which had a low positive predictive value of PAS (<1%). Seven patients had diffused complete cartilaginous rings. The other four patients were found to have prominent localized external compression of the trachea or bronchus. No coexisting intracardiac anomalies were found. Two patients had mental retardation. Seven patients underwent surgical correction without mortality or major complications. After surgery, significant improvement in PFT was shown in forced expiratory volume in 1 s (FEV1) and functional vital capacity (FVC).

CONCLUSIONS

This is the first study to determine the prevalence of PAS as 59 per million school-aged children by a large-scale screening using 2DE. Although the majority of children with PAS have associated TBA and impaired pulmonary function, all patients with PAS were unrecognized due to non-specific symptoms. Early identification of PAS and surgery result in significant improvement in pulmonary function.

The impact of evolving hand-carried echocardiographic technology on outpatient physical examination accuracy in pediatric cardiology

BACKGROUND

Cardiac auscultory skills are declining. Hand-carried ultrasound (HCU) has been proposed as a method to enhance diagnostic accuracy of the physical examination (PE). However, features of HCU devices are varied.

OBJECTIVE

The aim of this study was to compare the diagnostic accuracies of an experienced pediatric cardiac PE alone vs. the PE combined with the assistance of an HCU device when using 2 HCU devices with different capabilities. The results were compared with conventional echo as the reference standard.

METHODS

All outpatients seen by a single pediatric cardiologist underwent physical examination and HCU. Two HCU devices were compared. The first HCU device (HCU-1) had limited options with only 2-dimensional echo, limited Doppler, and a single transducer frequency (2.5 MHz). The second HCU device (HCU-2) was a unit with greater transducer choices and a wider variety of applications. A single echocardiologist performed the PEs & HCUs. Conventional echoes were performed by a pediatric sonographer and interpreted by a second pediatric echocardiologist. Examination accuracies centered on 3 broad areas including: cardiac shunts, valvular insufficiency, and valvular anatomy. The accuracy of the PE alone was compared with the accuracy of the combined PE & HCU-1 vs. PE & HCU-2.

RESULTS

Thirty patients total (3 months-19 years, 4-82 kg) were evaluated. Eighteen were examined with HCU-1 and 12 were examined with HCU-2. The accuracy of the combined PE & HCU-1 did not improve accuracy over the PE alone. However, the accuracy of the combined PE & HCU-2 was greater than the PE alone.

CONCLUSIONS

Use of a limited HCU device does not improve diagnostic accuracy over an experienced PE alone and may actually worsen diagnostic accuracy in some cases. However, the improvements in newer HCU devices may enhance diagnostic accuracy over the PE alone, even for experienced physicians.

Bedside echocardiography in the assessment of the critically ill

Advances in ultrasound technology continue to enhance its diagnostic applications in daily medical practice. Bedside echocardiographic examination has become useful to properly trained cardiologists, anesthesiologists, intensivists, surgeons, and emergency room physicians. Cardiac ultrasound can permit rapid, accurate, and noninvasive diagnosis of a broad range of acute cardiovascular pathologies. Although transesophageal echocardiography was once the principal diagnostic approach using ultrasound to evaluate intensive care unit patients, advances in ultrasound imaging, including harmonic imaging, digital acquisition, and contrast for endocardial enhancement, has improved the diagnostic yield of transthoracic echocardiography. Ultrasound devices continue to become more portable, and hand-carried devices are now readily available for bedside applications. This article discusses the application of bedside echocardiography in the intensive care unit. The emphasis is on echocardiography and cardiovascular diagnostics, specifically on goal-directed bedside cardiac ultrasonography.

Specific skill set and goals of focused echocardiography for critical care clinicians

Echocardiography in the critical care setting can provide crucial information about the patient's cardiac anatomy, ejection fraction, valvular function, and volume status. There is a need for more involvement by intensivists in performing focused echocardiographic studies as this modality has been well shown to improve patient care. Several factors limit the widespread use of this technology by intensivists that are noncardiologists. One of them is the lack of formal didactic and practical training programs in "goal-directed" echocardiography specifically oriented for the critical care specialist. Although it is clear that extensive training and experience are needed to perform and interpret a complete echocardiographic study, a growing body of literature demonstrates that noncardiology medical professionals can be trained to acquire and interpret echocardiographic imaging in a goal-directed or "focused" manner with an acceptable overall level of accuracy. Performance of such focused echocardiography by intensivists has been shown to provide new information not assessable by physical examination, and often leads to change in therapeutic management at the bedside. Echocardiography using the transthoracic approach is a noninvasive imaging modality and is of great value in the critical care setting because of its portability, widespread availability, and rapid diagnostic capability. Programs for intensivists should cover both the transthoracic and transesophageal approach. Focused training with the transthoracic approach should be offered to all intensivists, while training with the transesophageal approach should be offered to intensivists who desire more advanced training. This article will go over important issues regarding current and potential avenues for training of critical care physicians in performance of focused bedside echocardiography.

Cost‐Effective Strategies to Screen for Left Ventricular Systolic Dysfunction in the Community—A Concept

Early detection of heart failure caused by left ventricular systolic dysfunction (LVSD) is important, since early treatment has been shown to retard the progression of heart failure. While traditional echocardiography remains the standard for the detection of LVSD, electrocardiography and serum brain natriuretic peptide have also been shown to predict LVSD. Recently, hand-held echocardiography systems have been shown to have high predictive accuracy for assessment of LVSD. With the availability of the above bedside and relatively less-costly techniques, compared with traditional echocardiography, the major question now is what is the most cost-effective strategy for screening subjects for LVSD. To date, no studies have systematically addressed this issue, but preliminary data are becoming available. This review article discusses the pros and cons of various investigative strategies and likely cost-effectiveness of each strategy to screen for LVSD.

Noninvasive cardiac imaging in the evaluation of suspected acute coronary syndromes

Optimal management of patients presenting with chest pain to the emergency department is a major challenge, both in terms of a diagnostic dilemma and consumption of resources. The triage of such patients can be aided vastly by the appropriate use of noninvasive imaging. Noninvasive imaging modalities such as echocardiogram, radionuclide perfusion studies, positron emission tomography, cardiac magnetic resonance imaging and computed tomography have all been demonstrated to have favorable diagnostic and prognostic value, with an enhanced sensitivity to detect acute ischemia. A normal noninvasive evaluation in the appropriate clinical setting presents a strong argument against acute ischemia as an etiology of the chest pain. Randomized trials of both rest and stress imaging in the emergency department have confirmed a reduction in unnecessary hospitalizations and cost savings without compromising the safety of the patient. Cardiac magnetic resonance and computed tomography would provide an insight into subendocardial ischemia, the detection of which has previously been difficult, using single-photon emission tomography and echocardiography. In this review, novel hot-spot imaging modalities are discussed including infarct-avid imaging agents and ischemia-avid imaging agents, thus elucidating the pathophysiology of reperfusion-induced cell death. These agents represent work in evolution and are likely to be used routinely in the future as understanding of coronary syndromes and coronary artery disease becomes clearer.

A Pilot Study of the Clinical Impact of Hand-Carried Cardiac Ultrasound in the Medical Clinic

BACKGROUND

Small, hand-carried ultrasound devices have become widely available, making point-of-care echocardiograms (echos) accessible to all medical personnel as a means to augment and improve the increasingly inefficient physical examination. This study was designed to determine the clinical utility of hand-carried echo by medical residents in clinical decision making.

METHODS

Nine residents underwent brief, practical echo training to perform and interpret a limited hand-carried echo as an integral component of their office examination. The residents' hand-carried echo consisting of four basic views to define left ventricular (LV) function and wall thickness, valvular disease, and any pericardial effusions was compared to one performed by a level III echocardiographer.

RESULTS

Seventy-two consecutive medical clinic patients were enrolled with an average image acquisition time of 4.45 minutes. Residents obtained diagnostic images in 94% of the cases and interpreted them correctly 93% of the time. They correctly identified 92% of the major echo findings and 78% of the minor findings. Their diagnosis of LV dysfunction, valvular disease, and LV hypertrophy improved by 19%, 39%, and 14% with hand-carried echo compared to history and physical alone. Management decisions were reinforced in 76% and changed in 40% of patients with the use of hand-carried echo.

CONCLUSION

This study demonstrates that it is possible to train medical residents to perform an effective and reasonably accurate hand-carried echo during their physical examination, which can impact clinical management.

Handcarried ultrasound measurement of the inferior vena cava for assessment of intravascular volume status in the outpatient hemodialysis clinic

Accurate intravascular volume assessment is critical in the treatment of patients who receive chronic hemodialysis (HD) therapy. Clinically assessed dry weight is a poor surrogate of intravascular volume; however, ultrasound assessment of the inferior vena cava (IVC) is an effective tool for volume management. This study sought to determine the feasibility of using operators with limited ultrasound experience to assess IVC dimensions using hand-carried ultrasounds (HCU) in the outpatient clinical setting. The IVC was assessed in 89 consecutive patients at two outpatient clinics before and after HD. Intradialytic IVC was recorded during episodes of hypotension, chest pain, or cramping. High-quality IVC images were obtained in 79 of 89 patients. Despite that 89% of patients presented at or above dry weight, 39% of these patients were hypovolemic by HCU. Of the 75% of patients who left HD at or below goal weight, 10% were still hypervolemic by HCU standards. Hypovolemic patients had more episodes of chest pain and cramping (33 versus 14%, P = 0.06) and more episodes of hypotension (22 versus 3%, P = 0.02). The clinic with a higher prevalence of predialysis hypovolemia had significantly more intradialytic adverse events (58 versus 27%; P = 0.01). HCU measurement of the IVC is a feasible option for rapid assessment of intravascular volume status in an outpatient dialysis setting by operators with limited formal training in echocardiography. There is a poor relationship between dry weight goals and IVC collapsibility. Practice variation in the maintenance of volume status is correlated with significant differences in intradialysis adverse events.

Efficacy of Ultrasound-assisted Stress Testing Using a Hand-carried Ultrasound Device for Diagnosis of Coronary Artery Disease

BACKGROUND

Exercise echocardiography is an effective means of noninvasively detecting coronary artery disease (CAD), and hand-carried cardiac ultrasound (HCU) devices are now being used to diagnose CAD in emergency rooms and at bedsides.

OBJECTIVE

To compare the efficacies of exercise echocardiography with an HCU device (EchoCG-HCU) and exercise electrocardiography (ECG) in the diagnosis of CAD.

METHODS

Fifty-eight patients underwent symptom-limited treadmill exercise testing. Two-dimensional echocardiographic images were obtained from standard parasternal and apical windows at rest and immediately after exercise using an HCU device (180 PLUS SonoSite Inc, Bothell, Wash). Wall motion was scored for each of 16 left ventricular segments using a 5-point grading system. The development of new or worsening wall motion was considered to be indicative of ischemia.

RESULTS

When identifying CAD using exercise ECG, the sensitivity ws 63%, the specificity was 72%, and the diagnostic accuracy was 69%. By comparison, with exercise EchoCG-HCU the sensitivity was 68%, the specificity was 90%, and the diagnostic accuracy was 83%. Moreover, the specificity of exercise EchoCG-HCU was significantly higher than that of exercise ECG (p < .05).

CONCLUSION

Exercise EchoCG-HCU is at least as useful as exercise ECG for diagnosing CAD.

Easy Access Echocardiography for the General Practicioner: Results from the Parkstad Area in The Netherlands

Heart failure has a low incidence in general practice but is not easy to recognize in this setting. Frequently a normal electrocardiogram and a normal level of brain natriuretic peptide can exclude heart failure as a cause for dyspnea. Unfortunately the positive predictive value of both techniques is low. Imaging with echocardiography can then give the clue to the correct diagnosis. Also correct diagnosis of cardiac murmurs is not easy in general practice. Therefore an open access echocardiographic service was established in the south of the Netherlands. According to the existing services in the United Kingdom general practitioners in this area were able to ask for an echocardiogram without referring the patient to the cardiologist. During a period of 19 months 131 patients were referred to the Centre of Medical Diagnostics for an echocardiogram. In 12% of the patients referred for dyspnea a left ventricular ejection fraction lower than 40% was found. Fourty nine percent of the patients had diastolic dysfunction. In 33% heart failure could be excluded. In 62% of the patients referred for a cardiac murmur cardiac pathology could be found. In 38% of the patients the cardiac murmur could be established as a functional murmur. The service was found to improve practice by most of the general practitioners.

Teaching cardiac auscultation: effectiveness of a patient-centered teaching conference on improving cardiac auscultatory skills

OBJECTIVES

To assess the cardiac auscultatory skills of health care professionals before and after an actual (not simulated) patient-centered cardiac auscultation conference and to determine the effectiveness of this clinical teaching method on Improving diagnostic proficiency.

SUBJECTS AND METHODS

Seventy-eight participants at a conference on cardiac auscultation completed preconference and postconference examinations on their ability to diagnose a wide variety of heart sounds and murmurs. Among those tested, 46 (59%) were physicians: 17 (22%) were cardiologists, 19 (24%) were medical Interns or residents, 7 (9%) were cardiology fellows, 2 (3%) were general practitioners, and 1 (1%) was a pediatrician. Thirty-two (41%) of this group of respondents were nonphysicians: 14 (18%) were nurse practitioners, 9 (12%) were nurses, 6 (8%) were physician assistants, 2 (3%) were medical students, and 1 (1%) was a nonmedical professional. All participants were tested on 14 clinically Important cardiac auscultatory events directly recorded from actual (not simulated) patients and transmitted via wireless Infrared stethophones. The auscultatory events tested were wide physiologic splitting of S2 in right bundle branch block, fixed S2 splitting and systolic murmur in atrial septal defect, midsystolic click and late systolic murmur of mitral valve prolapse, S4 gallop, S3 gallop, opening snap of mitral stenosis, innocent systolic murmur, systolic murmur of mitral regurgitation, systolic murmur of tricuspid regurgitation, systolic murmur of hypertrophic obstructive cardiomyopathy, continuous murmur of patent ductus arteriosus, pericardial friction rub, prosthetic valve sounds, and alternation of heart sounds, heart murmurs, and the S3 gallop in congestive heart failure.

RESULTS

On the basis of the analysis of the 78 participants who completed preconference and postconference evaluations of the 14 selected cardiac auscultatory events, a preconference Identification score of 26.3% and a postconference score of 44.7% were observed. This represents a statistically significant overall Improvement in diagnostic proficiency (P < .001).

CONCLUSIONS

Cardiac auscultatory skills among today's health care professionals are extremely poor, regardless of the level and/or type of training of the professional. An actual (not simulated) patient-centered teaching conference is an effective clinical method of improving cardiac auscultatory skills and diagnostic proficiency of health care professionals.

Comparison of effectiveness of hand-carried ultrasound to bedside cardiovascular physical examination

This study compared the accuracy of cardiovascular diagnoses by medical students operating a small hand-carried ultrasound (HCU) device with that of board-certified cardiologists using standard physical examinations. Sixty-one patients (38% women; mean age 70 +/- 19 years) with clinically significant cardiac disease had HCU studies performed by 1 of 2 medical students with 18 hours of training in cardiac ultrasound and physical examinations by 1 of 5 cardiologists. Diagnostic accuracy was determined by standard echocardiography. Two-hundred thirty-nine abnormal findings were detected by standard echocardiography. The students correctly identified 75% (180 of 239) of the pathologies, whereas cardiologists found 49% (116 of 239) (p <0.001). The students' diagnostic specificity of 87% was also greater than cardiologists' specificity of 76% (p <0.001). For nonvalvular pathologies (115 findings), students' sensitivity was 61%, compared with 47% for cardiologists (p = 0.040). There were 124 clinically significant valvular lesions (111 regurgitations, 13 stenoses). Students' and cardiologists' sensitivities for recognizing lesions that cause a systolic murmur were 93% and 62% (p <0.001), respectively. Students' sensitivity for diagnosing lesions that produce a diastolic murmur was 75%; cardiologists recognized 16% of these lesions (p <0.001). The diagnostic accuracy of medical students using an HCU device after brief echocardiographic training to detect valvular disease, left ventricular dysfunction, enlargement, and hypertrophy was superior to that of experienced cardiologists performing cardiac physical examinations.

Bedside Ultrasonography in the ICU

This is the second of a two-part review on the application of bedside ultrasonography in the ICU. In this part, the following procedures will be covered: (1) echocardiography and cardiovascular diagnostics (second part); (2) the use of bedside ultrasound to facilitate central-line placement and to aid in the care of patients with pleural effusions and intra-abdominal fluid collections; (3) the role of hand-carried ultrasound in the ICU; and (4) the performance of bedside ultrasound by the intensivist. The safety and utility of bedside ultrasonography performed by adequately trained intensivists has now been well demonstrated. This technology, as a powerful adjunct to the physical examination, will become an indispensable tool in the management of critically ill patients.

The rate at which residents learn to use hand-held echocardiography at the bedside

PURPOSE

Because there is little information about the training that general internists require to perform hand-carried cardiac ultrasonography (HCU), we studied the rate of learning of a group of medical residents performing HCU after minimal formal training.

METHODS

Medical residents on the inpatient services at Johns Hopkins Bayview Medical Center received formal training in HCU consisting of 15-30 minutes of didactic instruction about the principles of echocardiography, followed by ongoing one-on-one instruction in performing HCU and subsequent ongoing one-on-one training from a certified echocardiography technician as they were doing scans. The residents were shown how to position the patient to obtain 2-dimensional echo images from the parasternal short and long axes and apical 4-chamber views, and how to obtain color-flow Doppler images across the mitral and aortic valves. Residents were asked to determine whether pericardial effusion was present and to assess left ventricular size, left ventricular function, and the mitral and aortic valves. The residents performed cardiac physical examination and HCU independently on patients who had a conventional transthoracic echocardiogram (CTTE) performed within 24 hours of the HCU. The residents' HCU results were compared with the CTTE results by a cardiologist specializing in echocardiography. The rates at which residents gained technical proficiency and skills in interpreting their studies were measured by linear regression to fit various outcome variables against their experience at scanning as gauged by the number of scans performed.

RESULTS

Thirty medical residents performed a total of 231 HCU studies. Linear regression models showed that the residents' overall technical proficiency skills improved at the rate of 0.79 (95% confidence interval [CI] 0.53-1.04) points on an overall assessment index (0-3 scale) per 10 scans completed. Interpretation accuracy improved at a rate of 1.01 (95% CI 0.69-1.39) points per 10 scans as measured by an interpretation accuracy index (0-3 scale). Because scanning efforts and instruction in HCU occurred during residents' usual rotation duties, some residents gathered experience in HCU slowly and sporadically.

CONCLUSION

This study, the first prospective, experimental effort of its kind, shows that residents as a group learned important aspects of HCU scanning and interpretation at a reasonably rapid rate.

Hand-held echocardiography: its use and usefulness

In recent years, several echocardiographic hand-held devices have been developed and are now available for a growing number of cardiologists. After the first clinical use 25 years ago, hand-held echocardiography (HHE) is now earning important commercial positions. Their transportability permits echo performance out the echo-labs and offers the possibility to make diagnosis in intensive care unit, emergency room, outpatient clinic, at the bedside, and even in ambulance. Experiences in the clinical setting have demonstrated the ability of HHE to detect multiple diseases including abdominal aortic aneurysms, left ventricular hypertrophy, regional wall motion abnormalities, pericardial and pleural effusions. At the present time, four varieties of HHE have to be recognized: the first includes high-cost, miniaturized machines, similar to the most advanced instrumentations, provided by new tools and imaging transfer systems; a second intermediate, middle-cost variety encompasses devices corresponding to standard echocardiography, but not miniaturized; according to the definition of the American Society of Echocardiography, a third and a fourth category comprise machines of weight lower than 2.7 kg, battery supplied and appropriately defined as "portable cardioschopes", which can be utilized as a technical refinement of physical examination. The use of HHE opens main controversy concerning their diagnostic accuracy, the opportunity to establish in which clinical settings they should be used and the identification of both potential users and required competence level. Preliminary experiences show the possibility to improve and anticipate diagnosis of several cardiovascular diseases but also the need to plan specific ultrasound training to avoid incorrect use of HHE.

The Use of Hand-carried Ultrasound in the Hospital Setting-A Cost-effective Analysis

OBJECTIVES

We sought to assess the accuracy of hand-carried ultrasound (HCU) in the prediction of a normal study, and its cost-effectiveness in reducing the number of standard departmental echocardiograms (SDE) performed on hospital inpatients.

METHODS

The setting was a district general hospital. Participants were 157 consecutive inpatients, mean age 68 (range: 18-97) years, 95 men (61%), referred for SDE. HCU was performed at the bedside as part of the clinical assessment. SDE was performed routinely. Main outcome measures were: (1) assessment of the accuracy of HCU in detection of a normal or abnormal study as determined by SDE; and (2) a cost-effectiveness analysis.

RESULTS

Indications for echocardiography were: left ventricular (LV) function assessment, n = 101 (64.3%); valvular abnormalities, n = 11 (7%); arrhythmia, n = 4 (2.6%); miscellaneous, n = 10 (6.4%); and no reason stated, 31 (19.7%). The sensitivity, specificity, and positive and negative predictive values of HCU predicting a completely normal scan were 74%, 96%, 94%, and 81%, respectively, and of predicting normal LV function in requests specific for LV function assessment were 81%, 100%, 100%, and 77%, respectively. If either all inpatients or those with requests for LV function assessment underwent HCU initially, and only those with abnormal scans underwent further SDE, there would be a 29% and 22% reduction in departmental workload and a cost saving of pound sterling 23,000 and pound sterling 30,000, respectively.

CONCLUSION

HCU is an accurate method of identifying patients with normal hearts as determined by SDE. Its routine use is cost-effective and can significantly reduce the number of SDE that need be performed.

Use of a hand-carried ultrasound device by critical care physicians for the diagnosis of pericardial effusions, decreased cardiac function, and left ventricular enlargement in pediatric patients

Prompt diagnosis of children with suggested cardiac disease in the acute care setting is critical for initiation of life-saving therapy. We hypothesized that pediatric critical care physicians could perform limited portable echocardiography in children. Portable hand-carried cardiac ultrasound units with 2.5-MHz phased-array transducers were used (Optigo, Philips Medical Systems, Andover, Mass). Noncardiologists were trained through a 1-hour introductory course and 2 hours of practical training. Portable echocardiography performed by noncardiologists was compared with a standard echocardiogram for diagnostic accuracy. In all, 23 patients (age 3 months-20 years) were screened during 18 months. The presence or absence of a pericardial effusion was correctly diagnosed in 21 of 23 patients (91%). Left ventricular size was correctly determined in 22 of 23 patients (96%). Left ventricular systolic function was correctly diagnosed in 22 of 23 patients (96%). These results show that, with appropriate instruction, pediatric critical care physicians are effective using limited portable echocardiography.

Effectiveness of echocardiographic imaging by nurses to identify left ventricular systolic dysfunction in high-risk patients

Recognizing left ventricular (LV) systolic dysfunction is critical. The investigators sought to evaluate whether nurses could be trained to use a hand-carried ultrasound (HCU) device to screen for LV systolic dysfunction in high-risk patients. Sixty-three patients from an outpatient diabetes clinic underwent brief echocardiographic examinations by nurses using HCU devices. Of the 63 patients enrolled in the study, 3 (4.7%) had LV systolic dysfunction. The nurses correctly identified these 3 patients as having LV systolic dysfunction (sensitivity 100%, negative predictive value 100%). The identification of occult LV systolic dysfunction in diabetic patients may allow the initiation of therapies known to improve prognosis.

Feasibility and potential clinical utility of goal-directed transthoracic echocardiography performed by noncardiologist intensivists using a small hand-carried device (SonoHeart) in critically ill patients

OBJECTIVE

This study was designed to assess the clinical applicability of a small, handheld, portable transthoracic echocardiography device by noncardiologist intensivists.

DESIGN

Prospective, observational study. After 10 one-hour tutorials, intensivists performed a limited transthoracic echocardiography (TTE) (2-4 views, without Doppler or M-mode) examination with the 5.6-lb SonoHeart Echo System (SonoSite, Bethell, WA) on critically ill patients admitted to the surgical intensive care unit. After initial cardiac clinical assessment in 90 patients, a limited TTE was performed by an intensivist to assess left ventricular (LV) function and LV volume status. Each study was immediately reviewed and repeated by an echocardiographer to determine the technical quality of the TTE and the accuracy of the intensivist's interpretation. Data were analyzed and presented in proportions using descriptive statistics.

SETTING

Surgical intensive care unit of an academic medical center.

PARTICIPANTS

Ninety critically ill adult patients.

INTERVENTIONS

After initial cardiac clinical assessment, a limited TTE was performed by an intensivist to assess LV size and function, to rule out significant pericardial effusions, and to estimate circulatory volume.

RESULTS

Intensivists successfully performed a diagnostic limited TTE in 94% of patients and interpreted their studies correctly in 84%. Limited TTE provided new cardiac information and changed management in 37% of patients. TTE added useful information in an additional 47% of patients but did not alter immediate management. The mean "goal-directed TTE" acquisition time was 10.5 +/- 4.2 minutes.

CONCLUSION

After a brief formal training in using this handheld echocardiographic system in intensive care unit patients, surgical intensivists successfully performed and correctly interpreted a limited TTE in critically ill patients. Limited TTE provided new information and altered management in a significant number of patients. This study supports incorporating bedside goal-directed, limited TTE into intensivists' training programs.