Doppler echocardiography of 119 normal-functioning St Jude Medical mitral valve prostheses: a comprehensive assessment including time-velocity integral ratio and prosthesis performance index.

The purpose of this study was to provide, in a large number of patients, comprehensive Doppler echocardiographic assessment of normal St Jude Medical mitral valve prosthesis function using Doppler-derived hemodynamic variables, including the mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio and prosthesis performance index. The pressure half-time was less than 130 milliseconds in all patients, and all but one patient had either a peak early mitral diastolic velocity of 2 m/s or less or a mitral valve prosthesis-to-left ventricular outflow tract time-velocity integral ratio of less than 2.2. There was a significant (P < .001) negative correlation between the prosthesis performance index and prosthesis size. This negative correlation suggests that there is more efficient use of the in vitro geometric orifice area with smaller prostheses.     

Proliferation of the surface-connected intracytoplasmic membranous network in skeletal muscle disease.

A surface-connected intracytoplasmic membranous (SCIM) network proliferates in skeletal muscle diseases and in myotubes grown in vitro. The authors observed frequent occurrence of "coated" microdomains in the form of budding vesicles in the proliferated components of this network and suspected a potential role the proliferated membranes might have in the endocytosis of molecules into myotubes undergoing repair or regeneration. Five-day-old myotubes in culture were incubated at 37 C and between 2 and 4 C with two tracers, Lucifer yellow and ferritin, both known to enter other types of cells via a fluid-phase endocytotic pathway. The differential penetration of Lucifer yellow at 37 C and below 2-4 C was examined by fluorescence microscopy and by electron microscopy. Lucifer yellow was rendered electron-opaque by photoreacting it with an intense light in the presence of DAB. Ferritin penetration at 37 C and between 2 and 4 C was compared and quantitated ultrastructurally. The authors found that endocytosis of the tracers into myotubes and eventually into lysosomes took place after the tracers had diffused into the lumen of the proliferated SCIM network. These processes were inhibited below 4 C. This finding, coupled with the presence of "coated" microdomains in the proliferated membranes, led us to suspect that the SCIM network may have a role in membrane turnover of metabolically active diseased muscle cells undergoing regeneration.     

Plasma HIV-1 RNA decline within the first two weeks of treatment is comparable for nevirapine, efavirenz, or both drugs combined and is not predictive of long-term virologic efficacy: A 2NN substudy

BACKGROUND: The initial rate of plasma HIV-1 RNA (pVL) decline has been proposed as a marker of early efficacy of antiretroviral therapy (ART) and a possible predictor of late efficacy. We compared the rate of pVL decline in patients starting ART with nevirapine (NVP), efavirenz (EFV), or both drugs combined in addition to lamivudine (3TC) and stavudine (d4T). METHODS: Analysis of the viral decay constant (VDc) during the first 2 weeks of treatment in patients enrolled in the 2NN study who remained on allocated treatment. RESULTS: The median VDc (log10 copies per day, [interquartile range]) was similar for NVP (0.30 [0.25-0.36], EFV (0.31 [0.27-0.37]), and NVP + EFV (0.30 [0.27-0.36]). Patients with a baseline pVL >100,000 copies/mL were 8.7 (95% confidence interval [CI]: 6.2-12.3) times more likely to have a VDc >75th percentile. A high VDc was not associated with plasma drug concentration or with a decreased risk of virologic failure at week 48 after the start of therapy (hazard ratio = 0.8, 95% CI: 0.6-1.2). CONCLUSION: NVP, EFV, or NVP + EFV in combination with 3TC and d4T show similar rates of pVL decline during the first 2 weeks of treatment. The VDc with these regimens is not predictive of late virologic efficacy.     

Clinical utility of routine screening for abdominal aortic aneurysm during echocardiography

BACKGROUND: The aim of this study was to determine the clinical utility of transthoracic echocardiography (TTE) as a screening method for the detection of abdominal aortic aneurysms (AAA). PATIENTS AND METHODS: Each patient who was referred to the echocardiography laboratory TTE was included into the study. After complete cardiac assessment the abdominal aorta was evaluated. Patients with a known, a clinically suspected, or a previously operated AAA were excluded. RESULTS: During the study period, 14,876 patients underwent TTE. 13,166 (88.5%) of the patients were 50 years and older. Of these 6953 (52.8%) were men and 6213 (47.2%) were women. A total of 108 (0.82%; 95% confidence interval (CI) 0.67-0.99) clinically unsuspected AAA of at least 3 cm in diameter (range 3 cm-6.8 cm) were detected. There were 93 (86.1%) men and 15 (13.9%) women with a mean age of 73.8 years (range 59-90). In 7 patients an AAA was suspected by TTE but not verified on subsequent abdominal ultrasound, as the diameter of the abdominal aorta was less than 3 cm. The prevalence of an AAA in patients 50 years and older was 1.34% (95% CI 1.08-1.64) for men and 0.24% (95% CI 0.14-0.40) for women. In patients less than 50 years old no aneurysm was detected. Seventeen patients who were found to have an AAA with a mean diameter of 4.4 cm (range 3-6 cm) underwent successful elective conventional AAA repair after a mean interval of 13.9 months (range 0.2-49 months) following the initial diagnosis. CONCLUSIONS: TTE performed in a highly selected cardiac patient group in a tertiary referral center is not a useful tool to screen for clinically unsuspected abdominal aortic aneurysms due to the low prevalence. The detection of an aneurysm should be confirmed by conventional abdominal ultrasound.     

Two dimensional echocardiographic demonstration of an unusual complication of aortic infective endocarditis

The two dimensional echocardiographic findings of aortic root abscess have been described. The echocardiographic findings in a patient with aortic valve endocarditis complicated by abscess formation, tear in the intima of the ascending aorta, and rupture of abscess cavity into the right ventricle are reported.     

The Preoperative Evaluation of Infective Endocarditis via 3-Dimensional Transesophageal Echocardiography

Transesophageal echocardiography continues to have a central role in the diagnosis of infective endocarditis and its sequelae. Recent technological advances offer the option of 3-dimensional imaging in the evaluation of patients with infective endocarditis. We present an illustrative case and review the literature regarding the potential advantages and limitations of 3-dimensional transesophageal echocardiography in the diagnosis of complicated infective endocarditis.A 51-year-old man, an intravenous drug user who had undergone bioprosthetic aortic valve replacement 5 months earlier, presented with prosthetic valve endocarditis. Preoperative transesophageal echocardiography with 3D rendition revealed a large abscess involving the mitral aortic intervalvular fibrosa, together with a mycotic aneurysm that had ruptured into the left atrium, resulting in a left ventricle-to-left atrium fistula. Three-dimensional transesophageal echocardiography enabled superior preoperative anatomic delineation and surgical planning. We conclude that 3-dimensional transesophageal echocardiography can be a useful adjunct to traditional 2-dimensional transesophageal echocardiography as a tool in the diagnosis of infective endocarditis.     

Patent foramen ovale in cryptogenic stroke: current understanding and management options

There is increasing interest in the association between patent foramen ovale (PFO) and documented stroke of unknown cause, commonly referred to as cryptogenic stroke. We reviewed the literature and, on the basis of the available data, designed a diagnostic and treatment algorithm for patients with PFO and cryptogenic stroke. Patent foramen ovale is relatively common in the general population, but its prevalence is higher in patients with cryptogenic stroke. Importantly, paradoxical embolism through a PFO should be strongly considered in young patients with cryptogenic stroke. There is no consensus on the optimal management strategy, but treatment options include antiplatelet agents, warfarin sodium, percutaneous device closure, and surgical closure. High-risk features in the patient's history (ie, temporal association between Valsalva-inducing maneuvers and stroke, coexisting hypercoagulable state, recurrent strokes, and PFO with large opening, large right-to-left shunt, or right-to-left shunting at rest, and a coexisting atrial septal aneurysm) should prompt PFO closure.