Complete Transesophageal Assessment of the Aortic Valve Using the Continuity Equation in Equivocal Cases of Aortic Stenosis.

BACKGROUND: The continuity equation (CE) used for evaluating aortic stenosis (AS) is based on values obtained from transthoracic echocardiography (TTE) with the assumption that the left ventricular outflow tract (LVOT) has a circular shape. Transesophageal echocardiography (TEE) may be used for accurate measurement of the LVOT cross-sectional area (CSA). Previous studies have focused on fusion from TEE for LVOT-CSA measurement and TTE for velocity time integrals (VTI) calculations. OBJECTIVES: To assess aortic valve area (AVA) using parameters obtained exclusively from TEE as an alternative approach. METHODS: Thirty patients with equivocal AS based on TTE were evaluated using TEE for further assessment. RESULTS: The mean pressure gradient across the aortic valve (AV) was 38 ± 5.9 and 37.9 ± 7.6 mmHg in TTE and TEE, respectively, P = 0.42. LVOT-CSA was larger in TEE (3.6 ± 0.3 vs. 3.4 ± 0.3 cm2, P = 0.049). VTI over the AVA was similar (98.54 ± 22.8 and 99.52 ± 24.52 cm in TTE and TEE, respectively, P = 0.608), while VTI across the LVOT was higher when measured by TTE (24.06 ± 5.8 vs. 22.03 ± 4.3 cm, P < 0.009). Using the CE, AVA was 0.82 ± 0.3 vs. 0.83 ± 0.17 cm2 in TEE vs. TTE, respectively, P = 0.608. Definitive grading was achieved in all patients (26 patients defined with severe AS and 4 with moderate). CONCLUSIONS: In equivocal cases of AS, full assessment using TEE may be a reliable modality for decision making.

Cardiac assessment accuracy by students using palm-held ultrasound compared to physical examination by skilled cardiologists: a pilot study with a single medical student.

BACKGROUND: Despite the inherent limitations of the traditional cardiac physical examination (PE), it has not yet been replaced by a more accurate method. METHODS: We hypothesized that a single medical student, following a brief training (two academic hours) with the PHU, will better identify abnormal findings including significant valvular diseases, pericardial effusion and reduced LV function, as compared to PE performed by senior cardiologists and cardiology fellows. Transthoracic echocardiogram (TTE) served as a 'gold standard'. RESULTS: Seventy-seven patients underwent TTE, of them 64 had an abnormal finding. PE identified 34 patients with an abnormal finding compared to 52 identified by PHU (p < 0.05). Ejection fraction (EF) below 50% was found in 35 patients on TTE, compared to only 15 and 6 patients by PE and PHU, respectively (p < 0.05). There was no difference in valvular dysfunction diagnosis detected by PE and medical students using PHU. The overall accuracy of PHU compared to TTE was 87%, with a specificity of 94% and sensitivity of 64% (the low sensitivity was driven mainly by EF assessment), whereas the accuracy of PE was 91%, specificity 91% and sensitivity 38% (again driven by poor EF assessment). CONCLUSIONS: Cardiac evaluation using PHU by a single medical student was able to demonstrate similar accuracy as PE done by cardiac specialists or cardiology fellows. The study topic should be validated in future studies with more medical students with a very brief training of cardiac ultrasound.

In-vitro assessment of the thrombolytic efficacy of therapeutic ultrasound.

BACKGROUND: Ultrasound is mainly used as a diagnostic tool. Several studies demonstrated that therapeutic ultrasound (TUS) can enhance thrombolysis, but the optimal mechanical parameters to achieve this biological effect are still unknown. METHODS: We assembled 46 blood clots in a closed in-vitro circulatory model. Clots were randomly divided into 7 groups, control group and six TUS groups of three frequencies (0.3, 0.5, 0.7 MHz) and six intensities (0.75, 1.5, 3, 237.7, 475, 950 W/cm2). Treatment was composed of 12 repetitions, 5 min US application and 3 min pause, lasting 93 min in total. Clots' weight and flow rate were measured before and after the treatment. RESULTS: Mean initial clot weight (0.318 ±â€¯0.129 g) and flow (0.53 ±â€¯0.31 ml/min) were comparable among the experimental groups. We found a final clot weights reduction (0.15 ±â€¯0.05, 0.16 ±â€¯0.06, 0.09 ±â€¯0.07, 0.21 ±â€¯0.09, 0.17 ±â€¯0.09, 0.17 ±â€¯0.07 and 0.18 ±â€¯0.02 g in groups 1 through 6, respectively) and a flow increase (30.61 ±â€¯19.76, 52.1 ±â€¯25.44, 28.78 ±â€¯8.15, 43.93 ±â€¯20.03, 40.86 ±â€¯18.25 and 45.10 ±â€¯22.20 ml/min in groups 1-6, respectively) in all TUS groups. Clot weight change (%) and flow increase reveals that the TUS profile f = 0.5 MHz I = 1.5 W/cm2 was most efficacious. In the control group, clot weight change was +6.3% of baseline and flow increase of 4.4% of baseline, whereas -75.4% of baseline and 209.3% of baseline in the f = 0.5 MHz I = 1.5 W/cm2 profile were noted, respectively. CONCLUSIONS: Our study proved that TUS at low frequency (0.5 MHz) is most effective, whereas changing the intensity of TUS has only a minor effect on clot lysis magnitude.

The subvalvular apparatus in rheumatic mitral stenosis: methods of assessment and therapeutic implications.

The assessment of the structure and function of the subvalvular apparatus (SVA) in patients with rheumatic mitral stenosis (MS) is complex, yet is of major importance prior to therapeutic decision making. Currently available methods of assessment are neither sufficiently accurate nor feasible. We review anatomic and functional aspects of the SVA and define SVA involvement in rheumatic MS. The role of various noninvasive and invasive methods for evaluating the integrity and function of SVA in rheumatic MS, as well as clinical implications and pitfalls in assessment of SVA are also discussed.