Indexing left ventricular wall thickness to body surface area improves prognostic value.

BACKGROUND: Guidelines provide normal ranges of left ventricular (LV) wall thicknesses (WT) without indexing. We hypothesized that indexing WT to body surface area (BSA) improves prognostic value. METHODS: We examined the relationship between WT and BSA in 9737 patients undergoing echocardiography without risk factors for LV hypertrophy other than obesity. We compared WT to BSA and examined the relationship of WT and LV mass index (LVMI) to mortality. RESULTS: There is a linear relationship between BSA and septal and posterior WT (r = 0.38, P < 0.001 for each). Higher quartiles of BSA were associated with increased WT (P < 0.001). After adjusting for age and gender, greater mean WT (MWT) (Hazards Ratio [HR] 1.10 per mm, 95% Confidence Interval [CI] 1.04-1.16, P = 0.001, C-statistic 0.66), LVMI (HR 1.01, 95% CI 1.001-1.01, P = 0.01, C-statistic 0.66), and indexed MWT (HR 1.34 per mm/m2 , 95% CI 1.23-1.47, P < 0.001, C-statistic 0.67) are each associated with increased mortality, with indexed MWT having the highest prognostic value. Each decile of indexed MWT ≥8th decile was associated with increased mortality compared to the 1st decile (P < 0.01 for each). Individuals with indexed MWT ≥8th decile (≥5.0 mm/m2 ) had increased adjusted mortality (HR 1.67, 95% CI 1.43-1.94, P < 0.001, C-statistic 0.67); this had improved prognostic value over guideline definitions of increased MWT (C-statistic 0.66) or LVMI (P = NS). CONCLUSIONS: We observe a linear relationship between BSA and WT. Indexing WT improves mortality prediction over LVMI and nonindexed WT. These findings support indexing WT to BSA.

A Pharmacy Blueprint for Electronic Medical Record Implementation Success.

OBJECTIVE: Implementation of an integrated, electronic medical record (EMR) has been promoted as a means of improving patient safety and quality. While there are a few reports of such processes that incorporate computerized prescriber order entry, pharmacy verification, an electronic medication administration record (eMAR), point-of-care barcode scanning, and clinical decision support, there are no published reports on how a pharmacy department can best participate in implementing such a process across a multihospital health care system. METHOD: This article relates the experience of the design, build, deployment, and maintenance of an integrated EMR solution from the pharmacy perspective. It describes a 9-month planning and build phase and the subsequent rollout at 8 hospitals over the following 13 months. RESULTS: Key components to success are identified, as well as a set of guiding principles that proved invaluable in decision making and dispute resolution. Labor/personnel requirements for the various stages of the process are discussed, as are issues involving medication workflow analysis, drug database considerations, the development of clinical order sets, and incorporation of bar-code scanning of medications. Recommended implementation and maintenance strategies are presented, and the impact of EMR implementation on the pharmacy practice model and revenue analysis are examined. CONCLUSION: Adherence to the principles and practices outlined in this article can assist pharmacy administrators and clinicians during all medication-related phases of the development, implementation, and maintenance of an EMR solution. Furthermore, review and incorporation of some or all of practices presented may help ease the process and ensure its success.

Antireflective surface structures in glass by self-assembly of SiO2 nanoparticles and wet etching.

We describe the fabrication of an antireflective surface structure with sub-wavelength dimensions on a glass surface using scalable low-cost techniques involving sol-gel coating, thermal annealing, and wet chemical etching. The glass surface structure consists of sand dune like protrusions with 250 nm periodicity and a maximum peak-to-valley height of 120 nm. The antireflective structure increases the transmission of the glass up to 0.9% at 700 nm, and the transmission remains enhanced over a wide spectral range and for a wide range of incident angles. Our measurements reveal a strong polarization dependence of the transmission change.

The impact of percutaneous coronary intervention on ischemic mitral regurgitation.

BACKGROUND AND AIM OF THE STUDY: The study aim was to determine if significant ischemic mitral regurgitation (IMR) is adequately addressed in patients undergoing multi-vessel percutaneous coronary intervention (PCI). METHODS: The cardiac catheterization laboratory database at the authors' institution was accessed over a five-year interval to identify those patients who had undergone multi-vessel PCI. Both, pre- and post-revascularization echocardiographic data were retrieved, and clinical data, MR presence and severity, and outcomes were each assessed. RESULTS: In total, 150 patients (100 males, 50 females; mean age 63 +/- 12 years) underwent PCI. Of these 150 patients, pre-procedural echocardiograms were not performed in 54 cases (35%); hence, the study group comprised 96 patients with both pre- and postprocedural echocardiograms. Of these patients, 21 (22%) had moderate or greater (2+) IMR. The severity of the IMR did not change significantly after multivessel PCI (2 +/- 0.8+ preoperatively versus 1.9 +/- 1.0+ postoperatively). CONCLUSION: Clinically significant IMR occurred not infrequently among patients treated with multivessel PCI, but the severity did not change with percutaneous revascularization, despite this being predominantly complete. In more than one-third of the patients, adequate pre-PCI echocardiography was unavailable, which suggested the possibility that not all IMR had been identified.

Mitral valve prolapse with left atrial enlargement out of proportion to mitral regurgitation.

Chronic severe mitral regurgitation (MR) is associated with compensatory dilation of the left atrium (LA) and left ventricle (LV). However, LA enlargement is not unique to patients with MR. Herein are reported the details of nine patients with mitral valve prolapse (MVP) and no more than mild MR, but in whom the LA enlargement is out of proportion to the MR severity. Because of the potential to overestimate MR severity using an integrative echocardiography/Doppler approach that includes evidence of chamber dilation in the diagnosis of severe MR, there may be significant clinical implications if the connective tissue abnormality underlying MVP or other factors results in an independent enlargement of the left atrium.

Pilot study of cardiac magnetic resonance imaging for detection of embolic source after ischemic stroke.

BACKGROUND: Transesophageal echocardiography (TEE) is the standard for evaluating cardioembolic sources of stroke, although many strokes remain cryptogenic after TEE. Cardiac magnetic resonance (CMR) imaging may have advantages over TEE. We performed a prospective pilot study comparing CMR to TEE after stroke to assist in planning future definitive studies. METHODS: Individuals with nonlacunar stroke within 90 days of undergoing clinical TEE were prospectively identified and underwent a 1.5 Tesla research CMR scan. Exclusion criteria included >50% relevant cervical vessel stenosis and inability to undergo nonsedated CMR. A descriptive comparison of cardioembolic source (intracardiac thrombus/mass, aortic atheroma ≥ 4 mm, or patent foramen ovale [PFO]) by study type was performed. RESULTS: Twenty patients underwent CMR and TEE a median of 6 days apart. The median age was 51 years (interquartile range [IQR] 40, 63.5), 40% had hypertension, 15% had diabetes, 25% had a previous stroke/transient ischemic attack, 5% had atrial fibrillation, and none had coronary disease or heart failure. No patient had intracardiac thrombus or mass detected on either study. Aortic atheroma ≥ 4 mm thick was identified by TEE in 1 patient. CMR identified aortic atheroma as <4 mm in this patient (3 mm on CMR compared with 5 mm on TEE). PFO was identified in 6 of 20 patients on TEE; CMR found only 1 of these. CONCLUSIONS: In this pilot study, TEE identified more potential cardioembolic sources than CMR imaging. Future studies comparing TEE and CMR after stroke should focus on older subjects at higher risk for cardiac disease to determine whether TEE, CMR, or both can best elucidate potential cardioembolic sources.

Prevalence and characteristics of unoperated patients with severe aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Although aortic valve replacement (AVR) is the preferred therapy for severe symptomatic aortic stenosis (AS), a substantial number of patients with indications for surgery do not undergo AVR. The study aim was to address, at multiple geographic locations and practice settings, the prevalence of unoperated patients with severe AS, and to explore potential barriers to intervention. METHODS: The medical records at 10 centers of various size and geographic distribution were reviewed retrospectively to identify patients with clinically severe AS (echocardiography/Doppler mean gradient > or = 40 mm Hg, effective orifice area < 1.0 cm2, or an overall interpretation of severe AS; and no clinical contradiction of severe AS). Demographic, clinical and outcomes data were recorded, including referral to a cardiothoracic surgeon (CTS), performance of AVR, and rationale when no AVR was performed. RESULTS: Of 952 patients who met the criteria for clinically severe AS, 497 (52%) were referred to a CTS for evaluation for AVR; subsequently, 395 patients (41%) underwent AVR and 557 (59%) were unoperated. Trends were similar across the institutions. Symptoms were present in 666 (79%) of 842 patients with available data, including 296 of 340 (87%) operated patients and 370 of 502 (74%) unoperated patients. Those patients referred to a CTS were younger, more often male, had higher aortic valve gradients, and more often were symptomatic. The dominant reasons cited for not undergoing AVR were comorbidities or high operative risk, advanced age or limited life expectancy, asymptomatic status, and patient or family refusal. The one-year survival was 94 +/- 2% for operated patients, and 69 +/- 3% for unoperated patients (66 +/- 3% for unoperated symptomatic and 78 +/- 5% for unoperated asymptomatic patients). CONCLUSION: In this multicenter survey, only about one-half of the patients with severe AS were referred to a CTS, and only about 40% underwent AVR. Three-quarters of unoperated patients were symptomatic. Referral to a CTS appeared more likely in the setting of symptoms of angina rather than heart failure or syncope, and elevated echocardiographic gradient rather than low valve area. Many patients who likely could benefit from AVR do not undergo evaluation for the condition, and similar observations were made at multiple medical institutions.

Exercise hemodynamics in valvular heart disease.

Exercise hemodynamics play an important role in the evaluation and management of patients with both severe stenotic or regurgitant valve lesions. Exercise testing in patients with valvular heart disease can help to unmask latent symptoms and define the timing of surgical intervention. Additionally, exercise-induced hemodynamics are an important tool to assess prosthetic valve function. This review summarizes both background literature and recent publications that assess the use of exercise hemodynamics in the evaluation and management of valvular heart disease.

Evaluation of mechanical heart valve size and function with ECG-gated 64-MDCT.

OBJECTIVE: The purpose of our study was to determine whether CT can accurately evaluate mechanical heart valve size and function. MATERIALS AND METHODS: Sixty-two patients with mechanical valves (37 single-disc, 27 bileaflet; 59 aortic, 5 mitral) were evaluated with ECG-gated 64-MDCT and transthoracic echocardiography; a subset of 10 patients underwent cinefluoroscopy. Two readers independently interpreted each study. RESULTS: The mean age of the patients was 46.4 +/- 14.4 years; 50 were men and 12 were women. There was excellent correlation, and differences between CT readers were absent to small in measuring the opening angle (r = 0.96, p < 0.001; 76.7 +/- 9.0 degrees vs 76.8 +/- 9.6 degrees , p = 0.73), annulus diameter (r = 0.96, p < 0.001; 25.9 +/- 3.3 vs 25.9 +/- 3.2 mm, p = 0.62), and geometric orifice area (r = 0.98, p < 0.001; 3.8 +/- 0.9 vs 3.6 +/- 0.8 cm(2), p < 0.001). There was strong correlation without difference in opening angle between CT and cinefluoroscopy (r = 0.77, p < 0.001; 79.2 degrees +/- 9.8 degrees vs 77.2 degrees +/- 15.5 degrees , p = 0.45). Compared with manufacturer specifications, CT reported opening angles that were smaller for single-disc valves (n = 36, 67.4 degrees +/- 5.7 degrees vs 75 degrees , p < 0.001) and similar for bileaflet valves (n = 42 for 21 valves, 83.8 degrees +/- 3.9 degrees vs 85 degrees , p = 0.05), valves, with small underestimation with CT versus specifications in annulus diameter (n = 41; r = 0.75, p < 0.001; 26.4 +/- 3.0 vs 27.5 +/- 3.3 mm, p = 0.003), and geometric orifice area (n = 35; r = 0.90, p < 0.001; 3.7 +/- 0.7 vs 3.8 +/- 0.8 cm(2), p = 0.04). Each disc closed fully on CT; none had more than mild regurgitation on echocardiography. CONCLUSION: CT can measure the size and function of mechanical valves with high interobserver agreement and results similar to specifications. The opening angle with CT strongly correlates with cinefluoroscopy. CT is promising for the assessment of mechanical valves.

Exercise stress testing in asymptomatic severe aortic stenosis.

Aortic valve replacement is the accepted therapy for patients with severe symptomatic aortic stenosis (AS). However, the timing of surgery in asymptomatic patients is less well defined, as some -- but not all -- asymptomatic patients are at increased risk. Exercise stress testing is an attractive means to assess risk in such patients, as it is readily available, standardized, physiological, and presents a controlled environment in which to assess whether patients truly are asymptomatic. This review summarizes existing literature and current guideline recommendations addressing exercise testing in asymptomatic patients with AS, and provides a recommendation for its use in a subset of patients.

In vitro two-dimensional echocardiographic imaging of a stented porcine bioprosthetic valve: the bent strut artifact.

BACKGROUND: Echocardiographic imaging of a stented valve bioprosthesis can reveal apparent inward deflection of one or more struts. It could be assumed that this finding is related to actual strut distortion as opposed to an artifact of off-axis imaging. OBJECTIVE: To determine whether normal (nondistorted) bioprosthetic struts can appear by artifact to be bent inward on two-dimensional echocardiographic imaging. METHODS: A production-quality porcine bioprosthetic aortic valve was imaged in vitro using standard two-dimensional echocardiographic techniques. Apparent strut distortion on echocardiographic imaging was investigated relative to prosthesis orientation to the transducer. RESULTS: The appearance of inward strut distortion was produced when two of three struts were simultaneously imaged, including imaging in an off-axis long axis orientation and from above or below the prosthesis. CONCLUSION: Apparent inward distortion of bioprosthetic struts can be simulated in vitro using a normal, nondistorted valve, and is common if two struts are simultaneously imaged. A finding of inward distortion of strut tips on in vivo imaging should be used with caution, since the finding may not be representative of actual strut anatomy.

EELS of niobium and stoichiometric niobium-oxide phases--Part II: quantification.

A comprehensive electron energy-loss spectroscopy (EELS) study of niobium (Nb) and stable Nb-oxide phases (NbO, NbO2, Nb2O5) was carried out. Part II of this work is devoted to quantitative EELS by means of experimental k-factors derived from the intensity ratio of the O-K edge and the Nb-M4,5 or Nb-M2,3 edges for all three stable Nb-oxides. The precision and accuracy of the quantification are investigated with respect to the influence of intensity-measurement energy windows, background subtraction, and sample thickness. Integration-window widths allowing optimum accuracy are determined. Owing to background-subtraction errors, the Nb-M4,5 edges rather than Nb-M2,3 are preferred for quantification. Different approaches are applied to improve the precision with regard to thickness-related errors. Thus, a precision up to +/-1.5% is achieved by averaging spectra from all three reference oxides to determine a k-factor using Nb-M4,5. Using the experimental k-factor, the determination of atomic concentration ratios CNb/CO in the range of 0.4 (Nb2O5) to 1 (NbO) was found to be possible with an accuracy of 0.6% (relative deviation between measured and nominal composition), whereas ratios of calculated partial ionization cross sections lead to less accurate results.

EELS of niobium and stoichiometric niobium-oxide phases--Part I: plasmon and near-edges fine structure.

A comprehensive electron energy-loss spectroscopy study of niobium (Nb) and stable Nb-oxide phases (NbO, NbO2, Nb2O5) was carried out. In this work (Part I), the plasmons and energy-loss near-edge structures (ELNES) of all relevant Nb edges (Nb-N2,3, Nb-M4,5, Nb-M2,3, Nb-M1, and Nb-L2,3) up to energy losses of about 2600 eV and the O-K edge are analyzed with respect to achieving characteristic fingerprints of Nb in different formal oxidation states (0 for metallic Nb, +2 for NbO, +4 for NbO2, and +5 for Nb2O5). Chemical shifts of the Nb-N2,3, Nb-M4,5, Nb-M2,3, and Nb-L2,3 edges are extracted from the spectra that amount to about 4 eV as the oxidation state increases from 0 for Nb to +5 for Nb2O5. Four different microscopes, including a 200 keV ZEISS Libra with monochromator, were used. The corresponding wide range of experimental parameters with respect to the primary electron energy, convergence, and collection semi-angles as well as energy resolution allows an assessment of the influence of the experimental setup on the ELNES of the different edges. Finally, the intensity of the Nb-L2,3 white-line edges is correlated with niobium 4d-state occupancy in the different reference materials.

Effect of Race on Echocardiographic Measures of Cardiac Structure and Function.

The relations between race and cardiac structure and function are incompletely understood. We hypothesized that race-specific differences in echocardiography measurements exist. We compared the relation between echocardiography measurements and race among 12,429 nonobese adults without known cardiovascular disease who underwent echocardiography. We compared measurements between whites (n = 10,508), blacks (n = 792), Asians (n = 628), Hispanics (n = 315), Native Americans (n = 34), and multiracial/other (n = 152) cohorts. Multivariate analysis compared measurements indexed to body surface area (BSA) between races and adjusted for variables including age, gender, and mean blood pressure. Mean age was 46.9 ± 17.4 years and 60.5% were women. After multivariable adjustment and using whites as a baseline, there were significant differences (p <0.05) in left ventricular end-diastolic diameter/BSA for blacks (-0.5 mm/m2), Asians (0.4 mm/m2), Hispanics (0.2 mm/m2), and multiracial/others (0.1 mm/m2); septal wall thickness/BSA for blacks (0.4 mm/m2) and Asians (0.1 mm/m2); posterior wall thickness/BSA for blacks (0.4 mm/m2), Asians (0.1 mm/m2), Hispanics (0.04 mm/m2), and multiracial/others (0.03 mm/m2); left atrial diameter/BSA for Asians (0.2 mm/m2), Hispanics (0.3 mm/m2), and multiracial/others (0.1 mm/m2); septal and lateral e' for blacks (-0.7 cm/s; -0.9 cm/s); and peak tricuspid regurgitation gradient for blacks (4.3 mm Hg) and Asians (-0.9 mm Hg). Race is associated with significant differences in left ventricular size, left atrial size, mitral annular velocity, and tricuspid regurgitation gradient. Normal reference ranges for echocardiography measurements should utilize racially diverse cohorts to prevent misclassification of echocardiography findings based on race.

Differences in Echocardiographic Measures of Aortic Dimensions by Race.

It is not clear whether there are differences in aortic dimensions by race. Our hypothesis was that race-specific differences in aortic size exist. We compared the relation between race and aortic dimensions among 15,295 adults without known risk factors for cardiovascular disease or aortic dilatation, who underwent clinically indicated transthoracic echocardiography. We compared inner edge-to-inner edge measurements between whites (n = 12,932), blacks (n = 958), Asians (n = 827), Hispanics (n = 366), Native Americans (n = 38), and others (n = 174). Multivariate analysis compared measurements indexed with body surface area (BSA) between races and adjusted for variables including age, gender, and mean blood pressure. Mean age was 49.9 ± 17.6 years, and 58.7% were female. On gender-specific comparisons, there were significant differences in aortic size between races (p <0.001 for each). Using whites as a baseline, multivariable analysis demonstrated that blacks had smaller BSA-indexed aortic sinus (-0.34 mm/m2, p <0.001) and ascending aorta (-0.43 mm/m2, p <0.001) dimensions; Asians had larger BSA-indexed aortic sinus (0.36 mm/m2, p <0.001), ascending aorta (0.41 mm/m2, p <0.001), and aortic arch (0.20 mm/m2, p = 0.002) dimensions; Hispanics had larger BSA-indexed aortic arch dimensions (0.15 mm/m2, p = 0.01); Native Americans had increased BSA-indexed aortic arch dimensions (0.32 mm/m2, p = 0.01); and other races had increased BSA-indexed aortic arch dimensions (0.11 mm/m2, p = 0.03). In a cohort without known risk factors for aortic dilatation, race is associated with significant differences in aortic dimensions. In conclusion, these findings suggest that reference ranges for aortic size should be established using racially diverse cohorts to prevent misdiagnosis of aortic dilatation based on race.

Persistent pulmonary hypertension after mitral valve surgery: does surgical procedure affect outcome?

BACKGROUND AND AIM OF THE STUDY: Recently published data suggest that prosthesis-patient mismatch is common after mitral valve replacement (MVR), and manifests as persistent pulmonary hypertension. The study aim was to determine the prevalence and severity of pulmonary hypertension after mitral valve surgery, including mitral valve repair, and to determine whether surgery type affects the prevalence of post-operative pulmonary hypertension. METHODS: Matched preoperative and > or =1 year postoperative Doppler estimates of right ventricular systolic pressure (RVSP) were evaluated in a cohort of 179 patients who underwent MVR or repair (33 after bioprosthetic valve replacement, 20 after mechanical valve replacement, 43 after physiological valve repair (predominantly for myxomatous disease), 78 after undersized annuloplasty for functional regurgitation, and five after repair of rheumatic stenosis). RESULTS: Patients undergoing repair of function mitral regurgitation had a lower left ventricular ejection fraction. The postoperative mean transmitral gradient was slightly higher for patients after bioprosthetic valve replacement (6.9 +/- 2.6 mmHg) compared to mechanical valve replacement (5.2 +/- 2.8 mmHg; p = 0.03), physiological repair (5.2 +/- 2.8 mmHg; p = 0.05), or repair of functional regurgitation (5.5 +/- 2.8 mmHg; p = 0.02). Pulmonary hypertension was common (present in 78% of patients before and 64% after surgery), and there were no significant differences between groups in the prevalence of postoperative pulmonary hypertension. The RVSP tended to decrease in all groups, but reached statistical significance only for patients undergoing bioprosthetic replacement (-9 +/- 24 mmHg; p = 0.04), mechanical replacement (-10 +/- 14 mmHg; p = 0.003) or physiological repair (-6 +/- 16 mmHg; p = 0.01). CONCLUSION: Pulmonary hypertension is common before and after mitral valve surgery. Although there were at least trends toward lower pulmonary artery pressures regardless of surgery type, significant decreases were noted only after MVR and physiological repair. A slightly higher postoperative mean transmitral gradient after bioprosthetic valve replacement may have contributed to postoperative pulmonary hypertension. The physiological repair of organic, non-rheumatic mitral regurgitation appears to offer favorable hemodynamics and a relatively low rate of postoperative pulmonary hypertension.

CT and MRI features of pseudoaneurysms of the mitral-aortic intervalvular fibrosa.

OBJECTIVE: To describe the CT and MR features of pseudoaneurysms of the mitral-aortic intervalvular fibrosa (PMAIVF). MATERIALS AND METHODS: This retrospective study included 9 patients with a diagnosis of PMAIVF who had CT or MRI within 3months of echocardiography. Echocardiography images were reviewed by a cardiologist and CT and MRI images were reviewed by two experienced cardiothoracic radiologists. RESULTS: Recognizable imaging features of PMAIVFs were communication with the Left ventricular outflow tract, location between the anterior leaflet of the mitral valve and the aortic valve, systolic expansion and diastolic collapse. CONCLUSION: CT and MRI show characteristic appearances of PMAIVFs and are complementary to echocardiography.